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Surgical and Nonsurgical Management of Mallet Finger: A Systematic Review

Published:November 22, 2017DOI:https://doi.org/10.1016/j.jhsa.2017.10.004

      Purpose

      The current literature describes multiple surgical and nonsurgical techniques for the management of mallet finger injuries, and there is no consensus on the indications for surgical treatment. The objective of this study was to determine, through a literature review, if any conclusions can be drawn concerning the indications for surgery in mallet finger injuries; the treatment outcomes of surgical versus nonsurgical management; the most effective methods of surgical and nonsurgical treatment; and the most common treatment complications of mallet finger injuries.

      Methods

      A systematic review of multiple databases was performed. English language clinical studies evaluating therapeutic interventions for mallet fingers that reported objective, standardized outcome measures were included. Basic science studies, cadaveric studies, conference abstracts, level V evidence studies, studies lacking statistical data, and tendinous injuries other than mallet fingers were excluded. Salvage procedures and studies evaluating exclusively chronic lesions were also excluded.

      Results

      Forty-four studies that reported clinical outcomes for the treatment of mallet finger injuries, 22 evaluating surgical treatments and 17 studies investigating nonsurgical treatments were included. The average distal interphalangeal joint extensor lag was 5.7° after surgical treatment and 7.6° after nonsurgical treatment. Complication rates of surgical and nonsurgical interventions were comparable (14.5% and 12.8%, respectively). Five studies directly compared the outcomes of surgical with nonsurgical management, with mixed results and recommendations.

      Conclusions

      Both surgical and nonsurgical treatments of mallet finger injuries lead to excellent clinical outcomes. Insufficient evidence is available to determine when surgical intervention is indicated. Based on our literature review, it appears that these treatments are equivalent and should be individualized to the patient.

      Type of study/level of evidence

      Therapeutic IV.

      Key words

      Mallet finger injuries are common tendon injuries in the finger. The extensor tendon of the distal interphalangeal (DIP) joint may sustain damage of varying degrees, from partial tear to complete rupture, as characterized by Doyle’s classification system
      • Doyle J.R.
      Extensor tendons: acute injuries.
      (Table 1, Fig. 1). The goal of management is to restore active DIP joint extension and prevent a swan neck deformity (DIP joint extensor lag and proximal interphalangeal joint hyperextension). Most mallet finger lesions can be treated nonsurgically by splinting, with the principal challenge being patient compliance.
      Table 1Doyle Classification
      TypeCharacteristics
      IClosed injury ± avulsion fracture
      IIOpen injury (laceration at or around DIP joint)
      IIIOpen injury + loss of skin and substance of the extensor tendon
      IVA: Growth plate fracture (pediatric)

      B: Fracture fragment involves 20% to 50% of articular surface (adult)

      C: Fracture fragment involves >50% of articular surface (adult)
      Figure thumbnail gr1
      Figure 1Doyle classification of mallet injuries.
      There is no consensus regarding the indications for surgical intervention. Traditionally, surgeons recommended surgery for injuries involving more than one-third of the DIP joint articular surface
      • Hamas R.S.
      • Horrell E.D.
      • Pierret G.P.
      Treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      • Houpt P.
      • Dijkstra R.
      • Storm van Leeuwen J.B.
      Fowler's tenotomy for mallet deformity.
      and those with subluxation or displacement.
      • McCue F.C.
      • Abbott J.L.
      The treatment of mallet finger and boutonniere deformities.
      • Stark H.H.
      • Gainor B.J.
      • Ashworth C.R.
      • Zemel N.P.
      • Rickard T.A.
      Operative treatment of intra-articular fractures of the dorsal aspect of the distal phalanx of digits.
      • Takami H.
      • Takahashi S.
      • Ando M.
      Operative treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      Others have proposed nonsurgical management for almost all cases of mallet finger injuries, challenging the surgical indications.
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      • Weber P.
      • Segmuller H.
      [Non-surgical treatment of mallet finger fractures involving more than one third of the joint surface: 10 cases].
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      • Facca S.
      • Nonnenmacher J.
      • Liverneaux P.
      [Treatment of mallet finger with dorsal nail glued splint: retrospective analysis of 270 cases].
      To our knowledge, only 1 decision algorithm is described in the literature,
      • Salazar Botero S.
      • Hidalgo Diaz J.J.
      • Benaida A.
      • Collon S.
      • Facca S.
      • Liverneaux P.A.
      Review of acute traumatic closed mallet finger injuries in adults.
      and it dictates the nonsurgical treatment of almost all mallet fingers, including injuries with fractures involving more than one-third of the articular surface with volar subluxation. Surgical treatment is advocated by these authors if the subluxation cannot be reduced by splinting.
      The objective of this study was to determine through a literature review if any conclusions can be drawn concerning the indications for surgery in mallet finger injuries; the treatment outcomes of surgical versus nonsurgical management; the most effective methods of surgical and nonsurgical treatment; and the most common treatment complications of mallet finger injuries.

      Materials and Methods

      We conducted a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses
      • Moher D.
      • Liberati A.
      • Tetzlaff J.
      • Altman D.G.
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.
      guidelines (Fig. 2). The search strategy was based on “mallet finger,” and the authors independently confirmed the search on March 5, 2017. The following databases were used: PubMed, Scopus, CINAHL, The Cochrane Library, and clinicaltrials.gov. Results from web search engines and references of included articles were reviewed for potentially relevant studies missed by the initial search. All abstracts were manually screened, and the full text of all studies with potential for final inclusion was evaluated for eligibility by the first author.
      Figure thumbnail gr2
      Figure 2Search strategy according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Forty-four studies were identified for inclusion, which are separated into 3 categories.
      Inclusion criteria required English language clinical studies evaluating any therapeutic intervention of mallet finger injury that reported an objective, standardized outcome measure with evidence level IV or higher. Basic science studies, cadaveric studies, conference abstracts, and studies not reporting clinical data were excluded. To eliminate the variability between salvage procedures and primary mallet injury treatments, we excluded studies that evaluated operations for mallet fingers that had previously failed nonsurgical treatment, as well as studies that exclusively investigated chronic lesions.
      The quality of all included studies was independently evaluated by both authors using the Quality Appraisal Tool (QAT) (Table 2; and Appendix A, Appendix B, Appendix C, available on the Journal's Web site at www.jhandsurg.org).
      • Roy J.S.
      • MacDermid J.C.
      • Woodhouse L.J.
      Measuring shoulder function: a systematic review of four questionnaires.
      Originally described by MacDermid et al,
      • MacDermid J.C.
      • Walton D.M.
      • Law M.
      Critical appraisal of research evidence for its validity and usefulness.
      this 12-item appraisal tool assesses the methodological characteristics of each study. Each item receives a score of 0, 1, or 2, indicating omission, partial fulfillment, and complete fulfillment of the item, respectively. Higher quality studies receive higher scores and therefore a higher percentage rating. If there was any disagreement in scoring, the authors reached agreement through discussion.
      Table 2Quality Appraisal Tool
      • MacDermid J.C.
      • Walton D.M.
      • Law M.
      Critical appraisal of research evidence for its validity and usefulness.
      ItemDescription
      1Thorough literature review to define the research question
      2Specific inclusion/exclusion criteria
      3Specific hypotheses
      4Appropriate scope of psychometric properties
      5Sample size calculation/justification
      6Appropriate retention/follow-up
      7Authors referenced specific procedures for administration, scoring, and interpretations of procedures
      8Measurement techniques were standardized
      9Data were presented for each hypothesis
      10Appropriate statistics-point estimate
      11Appropriate statistical error estimates
      12Valid conclusions and clinical recommendation
      Each item was assigned a score of 0, 1, or 2. Studies received a score of 0 if an item was omitted or not performed. A score of 1 was assigned for partial completion of an item. The maximum score of 2 was assigned for total fulfillment of the item.
      Continuous variable data were reported as mean and standard deviations from the mean. Categorical variable data were reported as frequency with percentages. Associations were reported as odds ratio with the corresponding 95% confidence interval. Statistical significance was set at P < .05.

      Results

      Forty-four studies were identified for final inclusion and analysis, with 22 evaluating surgical treatments, 17 evaluating nonsurgical treatments, and 5 studies comparing surgical with nonsurgical treatments. The Mean QAT rating of all studies was 73.4% ± 16.9% (range, 33.3% to 100%).

      Surgical treatment of mallet finger

      A total of 511 mallet fingers underwent surgery (Table 3). Four hundred and eighty cases were bony (associated fracture) injuries (93.9%), and 31 were tendinous (soft tissue only) injuries (6.1%). Of the 22 studies, 20 evaluated exclusively bony injuries. Two studied only soft tissue injuries. Thirteen studies used the Crawford criteria
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      to grade their outcomes (Table 4), and all other studies reported the mean DIP joint extension lag as an objective outcome measure. Several studies included standardized evaluation criteria such as the 3-tiered classification, described by Abouna and Brown
      • Abouna J.M.
      • Brown H.
      The treatment of mallet finger. The results in a series of 148 consecutive cases and a review of the literature.
      (Table 5) and Warren and Norris.
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.
      The average DIP joint extension deficit was 5.7°. There was no clinically notable difference in primary outcomes between bony and tendinous injuries in these studies. The mean postoperative DIP joint extensor deficit of the 480 bony injuries was 5.5° versus 7.5° for the 31 soft tissue injuries.
      Table 3Clinical Studies Evaluating Surgical Treatment of Mallet Finger
      AuthorsNo. of CasesBony vs SoftInterventionIndications for OperationResults
      Crawford Criteria EGFP (%)
      Percentages may not sum to 100 because of rounding.
      DIP Joint Extension Deficit (°)Other Evaluation Criteria Used
      Specific criteria for outcome categories were unique to the study unless otherwise specified.
      Complications
      Hamas et al
      • Hamas R.S.
      • Horrell E.D.
      • Pierret G.P.
      Treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      (1978)
      11BonyORIF K-wire + trans-DIP K-wireFractures >1/3 articular surface20
      Inoue
      • Inoue G.
      Closed reduction of mallet fractures using extension-block Kirschner wire.
      (1992)
      14BonyClosed reduction using extension-block K-wire (Ishiguro)Fractures >1/3 articular surface ± subluxated distal phalanxE57, G29, F7, P70
      Bischoff et al
      • Bischoff R.
      • Buechler U.
      • De Roche R.
      • Jupiter J.
      Clinical results of tension band fixation of avulsion fractures of the hand.
      (1994)
      51BonyTension band fixation wiringFractures >25% articular surface and rotated, distal phalanx subluxation1520% excellent, 39% satisfactory, 41% poor24 total complications: 4 skin breakdown, 6 infection, 3 secondary displacement, 6 nail growth disruption, 1 AVN, 1 secondary tendon rupture, 4 resorption of fragment
      Nakamura and Nanjyo
      • Nakamura K.
      • Nanjyo B.
      Reassessment of surgery for mallet finger.
      (1994)
      15SoftSutures + trans-DIP K-wire, early mobilizationPatients who required fine manual dexterity667% excellent or good, 20% fair, 13% poor0
      Darder-Prats et al
      • Darder-Prats A.
      • Fernandez-Garcia E.
      • Fernandez-Gabarda R.
      • Darder-Garcia A.
      Treatment of mallet finger fractures by the extension-block K-wire technique.
      (1998)
      22BonyClosed reduction using extension-block K-wire (Ishiguro)Fractures >1/3 articular surfaceE82, G14, F5-1 skin necrosis, 1 tendon rupture
      Bauze and Bain
      • Bauze A.
      • Bain G.I.
      Internal suture for mallet finger fracture.
      (1999)
      10BonySutures + trans-DIP K-wireFractures >30% articular surface11VAS and plain radiographs2 nail deformities, 1 superficial infection, 1 pin track infection
      Takami et al
      • Takami H.
      • Takahashi S.
      • Ando M.
      Operative treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      (2000)
      33BonyORIF with K-wiresFractures >1/3 articular surface with rotation, joint subluxation4Cosmetic: 73% excellent, 27% good1 fragmentation of a bone fragment and displacement of bone
      Hofmeister et al
      • Hofmeister E.P.
      • Mazurek M.T.
      • Shin A.Y.
      • Bishop A.T.
      Extension block pinning for large mallet fractures.
      (2003)
      24BonyClosed reduction using extension-block K-wire (Ishiguro)Fractures >25% articular surface or DIP subluxationE38, G54, F84Warren and Norris

      92% success, 4% improved, 4% failure
      2 superficial pin-site infections, 2 slight displacement of reduction
      Pegoli et al
      • Pegoli L.
      • Toh S.
      • Arai K.
      • Fukuda A.
      • Nishikawa S.
      • Vallejo I.G.
      The Ishiguro extension block technique for the treatment of mallet finger fracture: indications and clinical results.
      (2003)
      65BonyClosed reduction using extension-block K-wire (Ishiguro)Large bone fragment, palmar subluxation of loss of DIP joint congruity or extension lag >30°E46, G32, F20, P21 pin tract infection, 2 nail deformities
      Sorene and Goodwin
      • Sorene E.D.
      • Goodwin D.R.
      Tenodermodesis for established mallet finger deformity.
      (2004)
      16SoftTenodermodesis (sutures + trans-DIP K-wire)Fractures >1/3 articular surface should undergo ORIF, functionally important loss of extension in established lesions, cosmetic

      Passively correctable deformity with a good articular surface should undergo tenodermodesis
      950% excellent, 37.5% good, 12.5% fair0
      Teoh and Lee
      • Teoh L.C.
      • Lee J.Y.
      Mallet fractures: a novel approach to internal fixation using a hook plate.
      (2007)
      9BonyORIF with the “hook” plate techniqueFractures >1/3 articular surface, volar subluxation of distal phalanxE44, G560Warren and Norris

      100% success
      0
      Lee et al
      • Lee Y.H.
      • Kim J.Y.
      • Chung M.S.
      • Baek G.H.
      • Gong H.S.
      • Lee S.K.
      Two extension block Kirschner wire technique for mallet finger fractures.
      (2009)
      32BonyTwo extension block K-wire techniqueFractures >1/3 articular surface ± subluxated distal phalanxE69, G25, F63 nail ridging, 2 superficial infection, 2 transient nail deformity, 1 mild scarring at dorsal pin
      Lee et al
      • Lee S.K.
      • Kim K.J.
      • Yang D.S.
      • Moon K.H.
      • Choy W.S.
      Modified extension-block K-wire fixation technique for the treatment of bony mallet finger.
      (2010)
      29BonyTwo extension block K-wires + trans-DIP K-wireFractures >30% articular surface ± subluxated distal phalanxE73, G21, F640
      Kang and Lee
      • Kang H.J.
      • Lee S.K.
      Open accurate reduction for irreducible mallet fractures through a new pulp traction technique with primary tendon repair.
      (2012)
      16BonyOpen reduction, oblique wire fixation w/ pulp traction + primary extensor repairFractures >30% articular surface + subluxated distal phalanx, displacement >3 mm irreducible extension block pinningE69, G19, F12.53 transient nail deformity, 2 cases flexion lag 5° to 10°, 3 cases extension lag 5° to 10°
      Kakinoki et al
      • Kakinoki R.
      • Ohta S.
      • Noguchi T.
      • et al.
      A modified tension band wiring technique for treatment of the bony mallet finger.
      (2013)
      13BonyTension band wiring fixationApplicable for mallet fractures of all sizes and time after injury077% very satisfied, 23% satisfied1 osteophyte formation, 1 DIP joint motion restriction
      Miura
      • Miura T.
      Extension block pinning using a small external fixator for mallet finger fractures.
      (2013)
      12BonyExternal fixator + K-wireFractures >1/3 articular surfaceE10, G220
      Neuhaus et al
      • Neuhaus V.
      • Thomas M.A.
      • Mudgal C.S.
      Type IIb bony mallet finger: is anatomical reduction of the fracture necessary?.
      (2013)
      3BonyClosed reduction and internal fixation w/ K-wiresClosed bony mallet finger with subluxation00
      Acar et al
      • Acar M.A.
      • Guzel Y.
      • Gulec A.
      • Uzer G.
      • Elmadag M.
      Clinical comparison of hook plate fixation versus extension block pinning for bony mallet finger: a retrospective comparison study.
      (2015)
      32BonyHook plate fixation (n = 13) vs Extension block pinning (Ishiguro) (n = 19)Fractures >1/3 articular surface, volar subluxation of distal phalanxE62, G38 vs E53, G473 vs 4DASH: 0.5 vs 1.8

      VAS: 0.0 vs 0.6
      Hook plate: 3 nail deformity

      Extension block pinning: 1 nail deformity, 2 dorsal prominence, 1 degenerative joint
      Miranda et al
      • Miranda B.H.
      • Murugesan L.
      • Grobbelaar A.O.
      • Jemec B.
      PBNR: percutaneous blunt needle reduction of bony mallet injuries.
      (2015)
      12BonyPercutaneous blunt needle reductionFractures >1/3 articular surface, minimal bony contact postreduction, volar subluxation of distal phalanx51 dorsal bump with mild fragment displacement
      Imoto et al
      • Imoto F.S.
      • Leao T.A.
      • Imoto R.S.
      • Dobashi E.T.
      • de Mello C.E.
      • Arnoni N.M.
      Osteosynthesis of mallet finger using plate and screws: evaluation of 25 patients.
      (2016)
      25BonyORIF hook plate and screwFractures >1/3 articular surface, volar subluxation of distal phalanxE40, G600
      Kim et al
      • Kim D.H.
      • Kang H.J.
      • Choi J.W.
      The “Fish Hook” technique for bony mallet finger.
      (2016)
      26BonyK-wire catches dorsal fragment (fish hook) + trans-DIP K-wireFractures >1/3 articular surface, volar subluxation of distal phalanxE77, G19, F430
      Zhang et al
      • Zhang W.
      • Zhang X.
      • Zhao G.
      • Gao S.
      • Yu Z.
      Pressing fixation of mallet finger fractures with the end of a K-wire (a new fixation technique for mallet fractures).
      (2016)
      41BonyK-wire pressing fixation of fragment + trans-DIP K-wireFractures >1/4 articular surfaceE85, G10, F2, P246 nail deformity, 3 arthritis, 1 mild swan-neck deformity
      When 2 or more sets of results are reported with “vs,” the scores belong to each intervention method respectively in the order described.
      AVN, Avascular necrosis; DASH, Disabilities of the Arm, Shoulder and Hand; DIP, distal interphalangeal; EGFP, E (excellent), G (good), F (fair), P (poor); ORIF, open reduction internal fixation; VAS, visual analog scale.
      Percentages may not sum to 100 because of rounding.
      Specific criteria for outcome categories were unique to the study unless otherwise specified.
      Table 4Crawford Criteria (1984) Assessment of Mallet Finger Outcomes
      GradeCharacteristics of DIP Joint
      ExcellentFull extension

      Full flexion

      No pain
      GoodExtension deficit 0° to 10°

      Full flexion

      No pain
      FairExtension deficit 10° to 25°

      Any flexion loss

      No pain
      PoorExtension deficit >25°

      Persistent pain
      DIP, distal interphalangeal.
      Table 5Abouna and Brown Criteria (1968)
      GradeCharacteristics of DIP Joint
      SuccessExtension deficit <5°

      Normal flexion

      No stiffness
      ImprovedExtension deficit 6° to 15°

      Normal flexion

      No stiffness
      FailureExtension deficit >15°

      Any flexion loss

      DIP stiffness
      DIP, distal interphalangeal.
      The most commonly described surgical techniques included trans-DIP joint K-wire fixation, open reduction internal fixation with K-wire, and open suture repair of the tendon plus trans-DIP joint K-wire fixation (tenodermodesis). Acar et al
      • Acar M.A.
      • Guzel Y.
      • Gulec A.
      • Uzer G.
      • Elmadag M.
      Clinical comparison of hook plate fixation versus extension block pinning for bony mallet finger: a retrospective comparison study.
      were the only authors to directly compare 2 different surgical techniques, and it was the only surgical study that was evidence level III, with all other articles therapeutic level IV.

      Indications for surgical treatment

      The most frequently described surgical indications were size of fracture (more than one-third of articular surface involvement) (82.6%) and subluxation of the distal phalanx (60.9%). Cosmetic reasons and patients requiring fine manual dexterity were also cited as surgical indications, each appearing once in these studies (4.5%).

      Complications of surgical treatment

      A total of 74 complications (rate 14.5%) were reported (Table 3), with the most common being nail deformity (5.5%) and infection (2.5%). Other reported complications included secondary displacement of the reduction (1.4%), skin breakdown (1.2%), arthritis (0.8%), resorption of the bone fragment (0.8%), tendon rupture (0.4%), 1 instance of avascular necrosis of the fragment (0.2%), and 1 swan neck deformity (0.2%).

      Nonsurgical treatment of mallet finger

      A total of 1,098 mallet fingers in 17 studies were managed nonsurgically (Table 6). Seven hundred and twenty cases were soft tissue-only injuries. Two hundred and ninety-six cases had bony involvement. The type of injury was unspecified for 82 cases in the studies by Evans and Weightman
      • Evans D.
      • Weightman B.
      The Pipflex splint for treatment of mallet finger.
      and Tocco et al;
      • Tocco S.
      • Boccolari P.
      • Landi A.
      • et al.
      Effectiveness of cast immobilization in comparison to the gold-standard self-removal orthotic intervention for closed mallet fingers: a randomized clinical trial.
      the former study did not comment on injury type, whereas the latter mentioned soft tissue and bony injuries but did not specify how many of each they treated. The majority of studies, 12 of 17 (70.6%), included both bony and soft tissue mallet finger injuries and did not separate them in their outcomes analyses. Three studies investigated only soft tissue injuries, and 1 study investigated only bony mallet finger injuries with fracture fragments greater than one-third of the articular surface.
      Table 6Clinical Studies Evaluating Conservative Treatment of Mallet Finger
      AuthorsNo. of CasesBony vs SoftIntervention (Length of Immobilization)Treatment IndicationsRecommendationResults
      Crawford Criteria EGFP (%)
      Percentages may not sum to 100 because of rounding.
      DIP Joint Extension Deficit (°)Other Evaluation Criteria Used
      Specific criteria for outcome categories were unique to the study unless otherwise specified.
      Complications
      Crawford
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      (1984)
      15162 soft

      89 bony
      Stack splint

      (molded polythene splint)

      (8 wk)
      Tendon rupture or lacerationOpen reduction should only be reserved for distal phalanx subluxationsE64, G15, F11, P8-1 contact dermatitis
      Kinninmonth and Holburn
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      (1986)
      5442 soft

      12 bony
      Perforated thermopliable splint (n = 27) vs Stack splint (n = 27)

      (6–12 wk)
      All mallet fingers in their EDPerforated splint is superior to conventional splint, does not require removal for hygiene purposes89% vs 67% good/excellent for perforated vs conventional splints1 irritation secondary to exposure to hand disinfectant
      Evans and Weightman
      • Evans D.
      • Weightman B.
      The Pipflex splint for treatment of mallet finger.
      (1988)
      25UnknownPiplex splint, DIP joint extension, PIP joint flexion

      (5.8 wk; range 3–11 wk)
      Rupture or avulsion of extensor insertionPreventing full PIP extension shortens treatment time60% <10

      28% 10–20

      12% >20
      0
      Hovgaard and Klareskov
      • Hovgaard C.
      • Klareskov B.
      Alternative conservative treatment of mallet-finger injuries by elastic double-finger bandage.
      (1988)
      2521 soft

      4 bony
      Elastic double-finger bandage, allowing some degree of flexion

      (6–8 wk)
      Closed injuriesThis hygienic and simple bandage is equally effective as splinting368% good

      28% fair

      4% poor
      0
      Warren et al
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.
      (1988)
      10774 soft

      33 bony
      Stack splint (n = 58) vs Abouna splint (n = 49)

      (6 wk continuous + 2 wk night only)
      Exclude large bony fragment, fresh open injuries, epiphyseal injuries in childrenBoth splints are effective in many types of mallet finger. There is no category of injury not worth treating.

      Stack splint is preferred by the patient because of comfort
      Abouna and Brown:

      33% vs 39% success

      19% vs 14% improved

      48% vs 47% failure
      Abouna splint: 3 skin lacerations due to bare wire being exposed
      Shankar and Goring
      • Shankar N.S.
      • Goring C.C.
      Mallet finger: long-term review of 100 cases.
      (1992)
      10042 soft

      58 bony
      Stack splint (molded polythene splint)

      (6–9 wk)
      Closed injury w/ fracture <1/3 joint surfaceMallet fingers without substantial fracture can be treated with Stack splint1218 fingers became obstructive, 50 cold intolerance, 5 constant pain
      Maitra and Dorani
      • Maitra A.
      • Dorani B.
      The conservative treatment of mallet finger with a simple splint: a case report.
      (1993)
      6050 soft

      10 bony
      Custom-made padded aluminum alloy splint (n = 30) vs Stack splint (n = 30)

      (6 wk continuous + 3 wk night only)
      Closed injury w/o large fracture fragmentCustom-made padded aluminum splint equally effective as Stack splint but caused fewer skin complicationsAbouna and Brown:

      37% vs 33% success

      20% vs 20% improved

      43% vs 47% failure
      Custom aluminum splint: 1 dorsal ulcer, 1 skin maceration

      Stack splint: 3 dorsal ulcer, 6 skin maceration, 1 tape allergy
      Garberman et al
      • Garberman S.F.
      • Diao E.
      • Peimer C.A.
      Mallet finger: results of early versus delayed closed treatment.
      (1994)
      4027 soft

      13 bony
      Stack splint or aluminum foam splint (no difference in outcome)

      (7 wk; range 6–10 wk continuous + 4 wk night only)
      Closed injury w/ fracture <1/3 joint surface, no DIP joint subluxationRecommend splinting for closed mallet fingers w/ fracture <1/3 articular surface and no subluxation

      No difference in timing of presentation (4 d vs 8 wk)
      9Abouna and Brown (modified):

      80% success

      20% failure
      0
      Foucher et al
      • Foucher G.
      • Binhamer P.
      • Cange S.
      • Lenoble E.
      Long-term results of splintage for mallet finger.
      (1996)
      156146 soft

      10 bony
      Perforated thermoplastic splint

      (8 wk)
      Closed injury w/ fracture <1/3 joint surfacePerforated splint provided excellent results for closed mallet finger w/ fractures <1/3 articular surface70
      Lester et al
      • Lester B.
      • Jeong G.K.
      • Perry D.
      • Spero L.
      A simple effective splinting technique for the mallet finger.
      (2000)
      3727 soft

      10 bony
      Foam-padded aluminum splint

      (4–5 wk)
      Closed injuryRecommend splinting of DIP joint in 0° extension as opposed to hyperextensionE81, G14, F/P5Warren and Norris

      95% success

      5% failure
      0
      Richards et al
      • Richards S.D.
      • Kumar G.
      • Booth S.
      • Naqui S.Z.
      • Murali S.R.
      A model for the conservative management of mallet finger.
      (2004)
      3426 soft

      8 bony
      Custom-made thermoplastic splint

      (6 wk)
      Closed injury w/ fracture <1/3 joint surfaceCustom-made splint may be preferable to a standard splintAbouna and Brown:

      88% success

      12% failure
      0
      Kalainov et al
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      (2005)
      22BonyThermoplastic extension splint

      (5.5 wk + 3 wk night only)
      Closed and displaced fractures w/ >1/3 joint surfaceSupports splinting for closed and displaced mallet fractures >1/3 surface9VAS, ADL tolerance2 transient skin infection
      Pike et al
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      (2010)
      77SoftVolar aluminum (n = 27) vs dorsal aluminum (n = 26) vs custom thermoplastic splints (n = 24)

      (6 wk)
      Acute (<28d) Doyle 1 injury (closed injury ± fracture <1/3 joint surface)No statistically significant lag difference between these 3 splints6MHQDorsal padded aluminum splint: 1 full-thickness ulceration

      6 minor complications (2 in each group): irritation and altered sensation
      O’Brien and Bailey
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      (2011)
      6437 (14, 12, 11) soft

      27 (7, 9, 11) bony
      Stack (n = 21) vs dorsal aluminum (n = 21) vs custom thermoplastic splints (n = 22)

      (8 wk)
      Acute (<14d) Doyle 1 injury (closed injury ± fracture <1/3 joint surface)Custom thermoplastic splint less likely to result in treatment failure, but no extensor lag differenceE65, G18, F16, P23VASStack splint: 19 complications

      Dorsal aluminum: 8 complications

      Thermoplastic: 5 complications

      (12 Skin irritation/maceration, 9 poor splint fit, 4 splint dissatisfaction, 4 splint breakage, 3 pain)
      Tocco et al
      • Tocco S.
      • Boccolari P.
      • Landi A.
      • et al.
      Effectiveness of cast immobilization in comparison to the gold-standard self-removal orthotic intervention for closed mallet fingers: a randomized clinical trial.
      (2013)
      57Soft and small bony (<1/3)

      Not separated
      Quickcast splint (n = 27) vs lever-type thermoplastic splint (n = 30)

      (6–8 wk)
      Closed injury, ≥20° DIP joint lag passively correctable, fracture <1/3 joint surfaceCast immobilization more effective than the traditional approach—less edema and improved extensor lag5 vs 9Garberman success scaleCast: 4 trace maceration at latest follow-up

      Thermoplastic splint: 4 trace maceration at latest follow-up
      Altan et al
      • Altan E.
      • Alp N.B.
      • Baser R.
      • Yalcin L.
      Soft-tissue mallet injuries: a comparison of early and delayed treatment.
      (2014)
      45SoftExtension splinting–early vs delayed treatment (no difference in outcome)

      (6 wk)
      Closed tendinous injury (Doyle 1a)Conservative management of tendinous mallet finger is effective even if delayed presentation (up to 4 wk)E72 vs E59
      Good, fair, and poor results not reported, difference not statistically significant.
      71 skin maceration
      Saito and Kihara
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      (2016)
      44SoftTwo-step splint technique (n = 22) vs conventional splint (n = 22)

      (6 wk continuous + 2–4 wk night only)
      Acute (<14d) closed injury ± fracture, no subluxationInitial immobilization in 2-step splint is a good immobilization technique. Prefer 2-step splint over conventional7.5 vs 16Abouna and Brown:

      60% vs 10% success

      35% vs 40% improved

      5% vs 50% failure
      0
      When 2 or more sets of results are reported with “vs,” the scores belong to each intervention method respectively in the order described.
      ADL, activities of daily living; DIP, distal interphalangeal; EGFP, E (excellent), G (good), F (fair), P (poor); PIP, proximal interphalangeal; VAS, visual analog scale.
      Percentages may not sum to 100 because of rounding.
      Specific criteria for outcome categories were unique to the study unless otherwise specified.
      Good, fair, and poor results not reported, difference not statistically significant.
      All but one of these studies evaluated some form of splinting. Hovgaard and Klareskov
      • Hovgaard C.
      • Klareskov B.
      Alternative conservative treatment of mallet-finger injuries by elastic double-finger bandage.
      evaluated an elastic double-finger bandage for the treatment of mallet finger. The outcomes were overall favorable with nonsurgical treatment options. The majority of nonsurgical treatment studies reported DIP joint extension deficit as an outcome measure. Many also employed Abouna and Brown and Crawford criteria to grade outcomes. The average DIP joint extension deficit was 7.6°.
      Of the 17 studies, 9 were evidence level IV,
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      • Evans D.
      • Weightman B.
      The Pipflex splint for treatment of mallet finger.
      • Hovgaard C.
      • Klareskov B.
      Alternative conservative treatment of mallet-finger injuries by elastic double-finger bandage.
      • Shankar N.S.
      • Goring C.C.
      Mallet finger: long-term review of 100 cases.
      • Garberman S.F.
      • Diao E.
      • Peimer C.A.
      Mallet finger: results of early versus delayed closed treatment.
      • Foucher G.
      • Binhamer P.
      • Cange S.
      • Lenoble E.
      Long-term results of splintage for mallet finger.
      • Lester B.
      • Jeong G.K.
      • Perry D.
      • Spero L.
      A simple effective splinting technique for the mallet finger.
      • Richards S.D.
      • Kumar G.
      • Booth S.
      • Naqui S.Z.
      • Murali S.R.
      A model for the conservative management of mallet finger.
      1 study was evidence level III (retrospective cohort),
      • Altan E.
      • Alp N.B.
      • Baser R.
      • Yalcin L.
      Soft-tissue mallet injuries: a comparison of early and delayed treatment.
      3 studies were evidence level II (randomized controlled trials with <80% follow-up),
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      and 4 studies were evidence level Ib (randomized controlled trials).
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.
      • Maitra A.
      • Dorani B.
      The conservative treatment of mallet finger with a simple splint: a case report.
      • Tocco S.
      • Boccolari P.
      • Landi A.
      • et al.
      Effectiveness of cast immobilization in comparison to the gold-standard self-removal orthotic intervention for closed mallet fingers: a randomized clinical trial.
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      The most commonly evaluated nonsurgical treatment for mallet finger included Stack splints, custom thermoplastic splints, and foam-padded aluminum splints. The mean length of continuous immobilization among all the studies was 7.0 ± 1.2 weeks. No studies reported differences in outcomes between tendinous-only versus bony injuries.
      Seven studies directly compared the outcomes of 2 or more different types of splints. Most of these studies did not find statistically different outcomes in DIP joint extension deficit. Kinninmonth and Holburn
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      compared a perforated thermoplastic splint to a conventional Stack splint, contending that the perforated splint gave superior results, although no statistical analysis was performed. Warren et al
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.
      compared Stack and Abouna splints, and although both splints were deemed effective, the Stack splint was preferred by patients because of comfort. Maitra and Dorani’s study
      • Maitra A.
      • Dorani B.
      The conservative treatment of mallet finger with a simple splint: a case report.
      found equal effectiveness between a custom-made padded aluminum splint and the Stack splint, but the aluminum splint caused fewer skin complications. Pike et al
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      compared a volar aluminum splint, dorsal aluminum splint, and a custom thermoplastic splint, and found no statistically significant difference in extensor deficit. O’Brien and Bailey
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      compared Stack splints, dorsal aluminum splints, and custom thermoplastic splints, and found no difference in extensor lag. Tocco et al
      • Tocco S.
      • Boccolari P.
      • Landi A.
      • et al.
      Effectiveness of cast immobilization in comparison to the gold-standard self-removal orthotic intervention for closed mallet fingers: a randomized clinical trial.
      compared a Quickcast splint to a thermoplastic splint, and found that casting led to less edema and improved extensor lag, although there were no statistically significant differences. Saito and Kihara
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      compared a 2-step splint technique to a conventional figure-eight splint; the 2-step technique resulted in significantly better outcomes based on extension deficit and the Abouna-Brown criteria.

      Indications for nonsurgical treatment

      The most commonly reported indications for nonsurgical treatment were closed injury (82.4%) and a fracture fragment size <1/3 of the joint surface area (58.8%). Four studies (23.5%) explicitly required the absence of subluxation.
      • Garberman S.F.
      • Diao E.
      • Peimer C.A.
      Mallet finger: results of early versus delayed closed treatment.
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      Three studies (17.6%) required presentation to be acute (either within 14 or 28 d from injury).
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      One study specifically studied fractures with sizes >1/3 of the joint surface area.
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.

      Complications of nonsurgical treatment

      A total of 140 complications were reported (rate, 12.8%), almost all of which were mild and transient, including cold intolerance (4.6%) and mild skin issues (4.2%), such as skin irritation, transient infection, allergy, maceration, laceration, and ulcers. Only 1 case of serious full-thickness skin ulceration was reported, which occurred with a dorsal-padded aluminum splint and which required antibiotics.
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      Other reported complications included splint breakage, splint dissatisfaction, and persistent pain.

      Comparison between nonsurgical and surgical treatment of mallet finger

      A total of 174 cases were evaluated in 5 studies that directly compared nonsurgical (N = 96) with surgical (N = 78) treatment (Table 7). At least 90 cases (51.7%) involved a bony injury and 43 cases were solely tendinous (24.7%). One study did not specify how many of each injury type were included.
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      Three studies exclusively investigated bony injuries.
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      • Groebli Y.
      • Riedo L.
      • Della Santa D.
      • Marti M.C.
      Mallet fractures.
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      One study included both soft and bony injuries in its 2 treatment arms, reporting no difference in outcome between the injury types.
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      All studies compared splinting with trans-DIP joint K-wire treatment. One was level Ib (randomized controlled trial),
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      and the other 4 studies were evidence level III (retrospective cohort studies).
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      • Groebli Y.
      • Riedo L.
      • Della Santa D.
      • Marti M.C.
      Mallet fractures.
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      The recommendations and outcomes were varied.
      Table 7Clinical Studies Comparing Outcomes of Conservative Treatment Versus Surgical Treatment
      AuthorsNo. off CasesBony vs SoftConservative InterventionSurgical TreatmentResults
      RecommendationDIP Joint Extension Deficit (°)Other Evaluation Criteria UsedComplications
      Auchincloss
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      (1982)
      22

      19
      UnknownPryor and Howard splintTrans-DIP K-wireComparable results. Internal K-wire fixation may be better if delayed presentation10 vs 6Stark, Boyes, and Wilson

      50% vs 58% good

      32% vs 37% improved

      18% vs 5% unchanged
      Splint: 3 severe local irritation

      Surgery: 2 infection
      Wehbe and Schneider
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      (1984)
      15

      6
      BonyPalmar, dorsal aluminum-foam or Stack splint, castPull-out wire suture + K-wire internal fixation + trans-DIP K-wireMost mallet fractures can be treated conservatively, regardless of joint subluxation and size/amount of fragment displacement15 (combined)Splint: 1 superficial maceration, 2 erythema of DIP joint

      Surgery: 1 lost reduction, 1 pull-out button detachment, 1 lost splint and had arthrodesis that remained painful
      Groebli et al
      • Groebli Y.
      • Riedo L.
      • Della Santa D.
      • Marti M.C.
      Mallet fractures.
      (1987)
      4

      17
      BonyPryor polythene splintOpen reduction, trans-DIP K-wire + pull-out w/ hookAbandon conservative treatment early if no reduction. Surgery must be performed soon after injury. Splint is preferable if delayed presentation (>15 d)50% vs 53% excellent (DIP joint any deficit <10°)

      50% vs 28% moderate (DIP joint any deficit >10°)

      0% vs 18% failure (stiffness or arthrodesis)
      Splint: 0

      Surgery: 3 dystrophic pulp w/ hypoesthesia, 3 cold sensitivity
      Lubahn
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      (1989)
      11

      19
      BonyLink-type or dorsal aluminum-foam splintTrans-DIP K-wire + ORIF with K-wireOpen treatment preferable for fractures >1/3 articular surface and joint subluxation20–30 vs 0–2035° vs 55° average ROMSplint: 1 dorsal skin slough

      Surgery: 1 pin tract infection
      Renfree et al
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      (2016)
      44

      17
      10 bony, 34 soft vs 8 bony, 9 softCustom thermoplastic splintTrans-DIP K-wireRecommend extension splint for most closed soft or bony mallet injuries. K-wire fixation requires less stringent compliance, advantageous depending on occupation10 vs 5Splint: 1 swan neck deformity, 1 decubitus ulcer

      Surgery: 1 cellulitis, 1 pin migration, 1 swan neck deformity removed from final data analysis as the patient received both splint and pinning
      When 2 or more sets of results are reported with “vs,” the scores belong to each intervention method respectively in the order described.
      DIP, distal interphalangeal; ORIF, open reduction internal fixation; ROM, range of motion.
      Two studies found comparable clinical results between splinting and surgery. Auchincloss
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      and Renfree et al
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      did find improved DIP joint extension deficit with surgical treatment compared with splinting, but both suggested the treatments were comparable from a clinical standpoint. Auchincloss
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      suggested that internal K-wire fixation might achieve better results with delayed presentation.
      In contrast, a study by Groebli et al
      • Groebli Y.
      • Riedo L.
      • Della Santa D.
      • Marti M.C.
      Mallet fractures.
      reported that splinting is preferred over surgery in cases of delayed presentation (>15 d). However, these authors recommended surgery if incongruity of the joint surface persisted and for all open injuries. Lubahn
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      contends that surgery is preferable in cases with joint subluxation and fractures involving more than one-third of the articular surface, because he found improved DIP joint extensor lag and cosmetic appearance in those cases. In contrast, Wehbe and Schneider
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      recommend nonsurgical treatment for most mallet fingers regardless of joint subluxation or size of fracture.

      Discussion

      Indications for surgery in mallet finger injuries

      A 2008 Cochrane review by Handoll and Vaghela
      • Handoll H.H.
      • Vaghela M.V.
      Interventions for treating mallet finger injuries.
      analyzing 4 randomized clinical trials determined that there was insufficient evidence to recommend specific surgical indications. The majority of the surgical studies in this systematic review recommended using the size of the fracture fragment (82.6%) and subluxation of the distal phalanx (60.9%) as operative indications. Of note, failure of nonsurgical treatment was also one of the most commonly reported surgical indications encountered in the overall literature; over a third (35%) of the initial 43 surgical articles cite “failure of conservative treatment” as an indication for operation (Fig. 2). However, we excluded articles that studied operations for injuries that previously failed nonsurgical treatment as well as articles that studied exclusively chronic injuries (>28 d at presentation). We felt it would be inappropriate to compare salvage procedures with the primary treatment of mallet finger. On that basis, 22 surgical studies remained in our final analysis.
      Although not explicitly stated in the surgical articles, open injuries are likely indications for surgical management as well. We infer this based on the fact that 14 of 17 articles (82.4%) describing nonsurgical treatments required that the injury be closed in the patients they evaluated. In addition, the 3 articles that did not specify this requirement are the 3 oldest nonsurgical articles,
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      • Evans D.
      • Weightman B.
      The Pipflex splint for treatment of mallet finger.
      none of which received a full QAT score for detailing specific inclusion/exclusion criteria or demographic information (Appendix B). Therefore, it is possible that all patients treated nonsurgically in these studies sustained only closed injuries. Alternatively, almost none of the surgical studies specify how many of their injuries were open or closed. As a result, we were unable to directly compare outcomes of open versus closed mallet finger injuries under the various treatment methods.

      Treatment outcomes of surgical versus nonsurgical management

      Lubahn
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      compared splinting with surgery, and recommended surgical management for patients who desire better outcomes for functional or cosmetic reasons. Renfree et al
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      also compared splinting with K-wire fixation and contended that surgery is justified in patients who might have difficulty working with a splint, such as health care professionals or musicians. Overall, surgery may offer a slightly decreased, but likely clinically insignificant, mean DIP joint extension deficit compared with nonsurgical management, based on the interstudy calculations of 5.7° and 7.6°, respectively. This small advantage would be consistent with the 3 studies that directly compared splinting and surgery
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      and which found improved DIP extensor lag in surgical cases compared with cases treated with splinting. However, these authors still recommended nonsurgical treatment for most cases of mallet injury, as a slight quantitative advantage in extensor lag with surgery may not be clinically significant.
      There are those who recommend nonsurgical management for almost all mallet finger injuries, even in cases with large fracture fragments and distal phalanx subluxation.
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      • Weber P.
      • Segmuller H.
      [Non-surgical treatment of mallet finger fractures involving more than one third of the joint surface: 10 cases].
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      • Facca S.
      • Nonnenmacher J.
      • Liverneaux P.
      [Treatment of mallet finger with dorsal nail glued splint: retrospective analysis of 270 cases].
      Wehbe and Schneider
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      directly compared splinting with surgery, and they found that surgical treatment offered no advantage while increasing morbidity. Kalainov et al
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      evaluated the use of a thermoplastic splint in closed and displaced mallet finger fractures involving greater than one-third of the articular surface, finding good results and no difference in outcomes between those with DIP joint subluxation and those without.

      Most effective methods of surgical and nonsurgical treatment

      The optimal treatment for mallet finger injuries remains controversial. The large majority of surgical techniques involved some use of trans-DIP joint K-wire fixation. All but one nonsurgical management technique involved some form of splinting. Both surgical and nonsurgical techniques described in these studies generally yielded favorable outcomes with high proportions of cases receiving an “excellent”/“good” grade according to the Crawford criteria.
      There is also no consensus on how to best evaluate patient outcomes. Most of the included studies reported DIP joint extension deficit, but the clinical significance of this measure is debatable, as some authors contend that there is no correlation between extension lag and patient satisfaction.
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      • Gruber J.S.
      • Bot A.G.
      • Ring D.
      A prospective randomized controlled trial comparing night splinting with no splinting after treatment of mallet finger.
      • Okafor B.
      • Mbubaegbu C.
      • Munshi I.
      • Williams D.J.
      Mallet deformity of the finger. Five-year follow-up of conservative treatment.
      The Crawford criteria was the most commonly employed classification system. It is a 4-tiered grading system based on extension/flexion loss of the DIP joint and pain (Table 3) with high clinical relevance.
      • Salazar Botero S.
      • Hidalgo Diaz J.J.
      • Benaida A.
      • Collon S.
      • Facca S.
      • Liverneaux P.A.
      Review of acute traumatic closed mallet finger injuries in adults.
      The 3-tiered grading system described by Abouna and Brown
      • Abouna J.M.
      • Brown H.
      The treatment of mallet finger. The results in a series of 148 consecutive cases and a review of the literature.
      (Table 5) based on DIP joint extension/flexion and stiffness was also commonly used. The Michigan Hand Outcomes Questionnaire,
      • Chung K.C.
      • Hamill J.B.
      • Walters M.R.
      • Hayward R.A.
      The Michigan Hand Outcomes Questionnaire (MHQ): assessment of responsiveness to clinical change.
      visual analog scale, and Disabilities of the Arm, Shoulder, and Hand
      • Gummesson C.
      • Atroshi I.
      • Ekdahl C.
      The Disabilities of the Arm, Shoulder and Hand (DASH) outcome questionnaire: longitudinal construct validity and measuring self-rated health change after surgery.
      were also employed to measure patient satisfaction and tolerance of activities of daily living.

      Treatment complications of mallet finger injuries

      This systematic review demonstrated complication rates of 12.8% (nonsurgical) and 14.5% (surgical). The most common complications of surgical treatment were nail deformities and infection. Surgery was more likely to result in serious complications such as secondary displacement of the reduction, tendon rupture, and skin necrosis. In contrast, there was only 1 serious complication reported with nonsurgical treatment, where a full-thickness skin ulceration occurred with a dorsal-padded aluminum splint. The most common complications of nonsurgical treatment were mild and transient skin issues such as irritation, laceration, and maceration. Although cold intolerance was the complication with the highest number of reported cases, all 50 cases were described in a single study,
      • Shankar N.S.
      • Goring C.C.
      Mallet finger: long-term review of 100 cases.
      making it less likely to be the most common complication of nonsurgical treatment in general.
      Overall, our nonsurgical and surgical complication rates of 12.8% and 14.5%, respectively, are lower than some previously reported rates. A study by Stern and Kastrup
      • Stern P.J.
      • Kastrup J.J.
      Complications and prognosis of treatment of mallet finger.
      suggests that the complication rate of splinting is as high as 45%, and of surgery as high as 53%. King et al
      • King H.J.
      • Shin S.J.
      • Kang E.S.
      Complications of operative treatment for mallet fractures of the distal phalanx.
      reported surgical complication rates of 41%. Other studies have suggested that complications occur less frequently with surgery compared with nonsurgical treatments, which differs from our findings.
      • Salazar Botero S.
      • Hidalgo Diaz J.J.
      • Benaida A.
      • Collon S.
      • Facca S.
      • Liverneaux P.A.
      Review of acute traumatic closed mallet finger injuries in adults.
      Our findings are similar to previously published reports that complications of surgical intervention are more severe than those of nonsurgical treatment, with nail deformity and infection being the most common. Overall, the treatments analyzed appeared to be very effective in preventing swan neck deformities, with a total of 2 mild occurrences isolated to 2 studies. One occurred in a patient having received an operation involving trans-DIP joint K-wire fixation (Zhang et al
      • Zhang W.
      • Zhang X.
      • Zhao G.
      • Gao S.
      • Yu Z.
      Pressing fixation of mallet finger fractures with the end of a K-wire (a new fixation technique for mallet fractures).
      ). The other was observed in a patient treated by splinting who presented with a long-term swan neck deformity (Renfree et al
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      ). An additional case of swan neck deformity did occur in Renfree et al’s study, but it was excluded from their final data analysis because the patient underwent both splinting and pinning.

      Bony versus tendinous mallet finger injuries

      It is reasonable to think that management would differ between bony (associated fracture) injuries and tendinous (soft tissue only) injuries. However, outcomes appear to be comparable when the associated fracture is small (<1/3 joint surface). Indeed, most nonsurgical management studies included both small bony and soft tissue injuries without separating them; none of these studies report a difference in outcomes between these 2 injury types. Moreover, Doyle type I injuries do include both isolated tendon injuries and small avulsion fractures. It was not possible to separate them in our analysis, because the vast majority of the studies did not separate out the type, and there would have only been a small number of studies left to evaluate.
      Most of the studies regarding surgical management, however, evaluated various operations on only bony mallet fingers; 2 surgical articles also evaluated open suture repair of the tendon plus trans-DIP joint K-wire fixation on isolated tendinous mallet fingers. Our analysis suggests no important differences in postoperative outcomes between these injury types, although we were not able to perform formal statistical tests, because individual patient data were not always reported.

      Impact of time from injury to presentation

      There remains controversy in the literature regarding the impact that delay from injury and presentation has on outcomes. We excluded all studies investigating exclusively chronic injuries as we aimed to analyze primary treatments rather than salvage procedures. The average time to presentation was less than 28 days in all included studies specifying chronicity of injury. However, many of these articles did include patients with delayed presentation. Including both chronic and acute injuries may affect conclusions drawn from interstudy analyses, but we did not find differences in outcomes. Only one of the surgical articles separates patients who were treated acutely, subacutely, and chronically (>30 d), and the authors found no difference in outcome based on chronicity.
      • Hofmeister E.P.
      • Mazurek M.T.
      • Shin A.Y.
      • Bishop A.T.
      Extension block pinning for large mallet fractures.
      Five studies evaluating nonsurgical treatments stratified patients by the time of presentation. Similar to the sole surgical study, none of these studies report any association of outcomes with regard to delay in treatment; 3 studies specifically contend that there was no difference,
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      • Garberman S.F.
      • Diao E.
      • Peimer C.A.
      Mallet finger: results of early versus delayed closed treatment.
      • Altan E.
      • Alp N.B.
      • Baser R.
      • Yalcin L.
      Soft-tissue mallet injuries: a comparison of early and delayed treatment.
      whereas the other 2 offered neither statistical analysis nor commentary.
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.

      Study limitations

      This systematic review is limited by the level of evidence and qualities of the studies analyzed. Although most studies did report similar objective criteria to measure treatment outcomes, many studies employed different grading systems. Only 4 of these 44 studies performed power analyses (see Appendix B for nonsurgical articles). Moreover, the lack of congruity in injury type and patient-specific characteristics such as comorbidities further prohibited a meta-analysis. We used weighted means from individual studies for comparison. Certain studies had to be excluded from quantitative comparison if they reported only ranges or categories of treatment results, precluding calculation of a mean value. There were inconsistencies in reporting treatment complications, and when multiple complications occurred in a single case, an accurate complication rate was difficult to determine. Patient adherence to treatment was often not reported, and therefore the efficacy of any treatment modality may not have been accurate.
      The majority of the studies included were evidence level IV. Studies with higher evidence levels that did compare 2 or more treatment techniques were small, nonblinded trials that often had substantial loss to follow-up, making them susceptible to detection bias and transfer bias. Selection bias was also present, as many of these studies were retrospective reviews. However, the methodological quality of the studies analyzed in this systematic review was overall quite strong, with a QAT rating of 73.4%—comparable with that of the original study where this tool was employed (mean, 71.3%).
      • Roy J.S.
      • MacDermid J.C.
      • Woodhouse L.J.
      Measuring shoulder function: a systematic review of four questionnaires.
      A number of different surgical and nonsurgical treatments of mallet finger injury offer excellent clinical outcomes. Although some splints may be preferred for various reasons, there are no statistically significant differences in outcome. There is a dearth of recent studies that compare surgical with nonsurgical treatments of mallet finger injuries. There remains insufficient evidence to determine when surgical intervention is indicated. Based on our literature review, it appears that these treatments are equivalent and treatment should be individualized to the patient.

      Appendix

      Appendix AMethodological Quality of Operative Studies Assessed by the Quality Appraisal Tool
      StudyItem Number; Item Evaluation Criteria
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.
      (Maximum = 2; Minimum = 0)
      Total (%)
      Authors (Year)123456789101112
      Hamas et al
      • Hamas R.S.
      • Horrell E.D.
      • Pierret G.P.
      Treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      (1978)
      21100221110150.00
      Inoue
      • Inoue G.
      Closed reduction of mallet fractures using extension-block Kirschner wire.
      (1992)
      12001220110145.83
      Bischoff et al
      • Bischoff R.
      • Buechler U.
      • De Roche R.
      • Jupiter J.
      Clinical results of tension band fixation of avulsion fractures of the hand.
      (1994)
      22111221110162.50
      Nakamura and Nanjyo
      • Nakamura K.
      • Nanjyo B.
      Reassessment of surgery for mallet finger.
      (1994)
      12111221221275.00
      Darder-Prats et al
      • Darder-Prats A.
      • Fernandez-Garcia E.
      • Fernandez-Gabarda R.
      • Darder-Garcia A.
      Treatment of mallet finger fractures by the extension-block K-wire technique.
      (1998)
      22121222221287.50
      Bauze and Bain
      • Bauze A.
      • Bain G.I.
      Internal suture for mallet finger fracture.
      (1999)
      21111122222279.17
      Takami et al
      • Takami H.
      • Takahashi S.
      • Ando M.
      Operative treatment of mallet finger due to intra-articular fracture of the distal phalanx.
      (2000)
      22111121210266.67
      Hofmeister et al
      • Hofmeister E.P.
      • Mazurek M.T.
      • Shin A.Y.
      • Bishop A.T.
      Extension block pinning for large mallet fractures.
      (2003)
      22210222221283.33
      Pegoli et al
      • Pegoli L.
      • Toh S.
      • Arai K.
      • Fukuda A.
      • Nishikawa S.
      • Vallejo I.G.
      The Ishiguro extension block technique for the treatment of mallet finger fracture: indications and clinical results.
      (2003)
      22110221211270.83
      Sorene and Goodwin
      • Sorene E.D.
      • Goodwin D.R.
      Tenodermodesis for established mallet finger deformity.
      (2004)
      22101221210266.67
      Teoh and Lee
      • Teoh L.C.
      • Lee J.Y.
      Mallet fractures: a novel approach to internal fixation using a hook plate.
      (2007)
      12111222221279.17
      Lee et al
      • Lee Y.H.
      • Kim J.Y.
      • Chung M.S.
      • Baek G.H.
      • Gong H.S.
      • Lee S.K.
      Two extension block Kirschner wire technique for mallet finger fractures.
      (2009)
      22211221121279.17
      Lee et al
      • Lee S.K.
      • Kim K.J.
      • Yang D.S.
      • Moon K.H.
      • Choy W.S.
      Modified extension-block K-wire fixation technique for the treatment of bony mallet finger.
      (2010)
      22210222221283.33
      Kang and Lee
      • Kang H.J.
      • Lee S.K.
      Open accurate reduction for irreducible mallet fractures through a new pulp traction technique with primary tendon repair.
      (2012)
      22111222221283.33
      Kakinoki et al
      • Kakinoki R.
      • Ohta S.
      • Noguchi T.
      • et al.
      A modified tension band wiring technique for treatment of the bony mallet finger.
      (2013)
      22120222221283.33
      Miura
      • Miura T.
      Extension block pinning using a small external fixator for mallet finger fractures.
      (2013)
      21220222222287.50
      Neuhaus et al
      • Neuhaus V.
      • Thomas M.A.
      • Mudgal C.S.
      Type IIb bony mallet finger: is anatomical reduction of the fracture necessary?.
      (2013)
      22110221111162.50
      Acar et al
      • Acar M.A.
      • Guzel Y.
      • Gulec A.
      • Uzer G.
      • Elmadag M.
      Clinical comparison of hook plate fixation versus extension block pinning for bony mallet finger: a retrospective comparison study.
      (2015)
      22221222222295.83
      Miranda et al
      • Miranda B.H.
      • Murugesan L.
      • Grobbelaar A.O.
      • Jemec B.
      PBNR: percutaneous blunt needle reduction of bony mallet injuries.
      (2015)
      21100221221162.50
      Imoto et al
      • Imoto F.S.
      • Leao T.A.
      • Imoto R.S.
      • Dobashi E.T.
      • de Mello C.E.
      • Arnoni N.M.
      Osteosynthesis of mallet finger using plate and screws: evaluation of 25 patients.
      (2016)
      22110221121166.67
      Kim et al
      • Kim D.H.
      • Kang H.J.
      • Choi J.W.
      The “Fish Hook” technique for bony mallet finger.
      (2016)
      22111221121170.83
      Zhang et al
      • Zhang W.
      • Zhang X.
      • Zhao G.
      • Gao S.
      • Yu Z.
      Pressing fixation of mallet finger fractures with the end of a K-wire (a new fixation technique for mallet fractures).
      (2016)
      22221222221291.67
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.
      Appendix BMethodological Quality of Conservative Studies Assessed by the Quality Appraisal Tool
      StudyItem Number; Item Evaluation Criteria
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: Sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.
      (Maximum = 2; Minimum = 0)
      Total (%)
      Authors (Year)123456789101112
      Crawford
      • Crawford G.P.
      The molded polythene splint for mallet finger deformities.
      (1984)
      01001211110241.67
      Kinninmonth and Holburn
      • Kinninmonth A.W.
      • Holburn F.
      A comparative controlled trial of a new perforated splint and a traditional splint in the treatment of mallet finger.
      (1986)
      21100021211150.00
      Evans and Weightman
      • Evans D.
      • Weightman B.
      The Pipflex splint for treatment of mallet finger.
      (1988)
      20100110110133.33
      Hovgaard and Klareskov
      • Hovgaard C.
      • Klareskov B.
      Alternative conservative treatment of mallet-finger injuries by elastic double-finger bandage.
      (1988)
      01101011110133.33
      Warren et al
      • Warren R.A.
      • Norris S.H.
      • Ferguson D.G.
      Mallet finger: a trial of two splints.
      (1988)
      22210222211279.17
      Shankar and Goring
      • Shankar N.S.
      • Goring C.C.
      Mallet finger: long-term review of 100 cases.
      (1992)
      22110221221275.00
      Maitra and Dorani
      • Maitra A.
      • Dorani B.
      The conservative treatment of mallet finger with a simple splint: a case report.
      (1993)
      21210212222279.17
      Garberman et al
      • Garberman S.F.
      • Diao E.
      • Peimer C.A.
      Mallet finger: results of early versus delayed closed treatment.
      (1994)
      21210221221275.00
      Foucher et al
      • Foucher G.
      • Binhamer P.
      • Cange S.
      • Lenoble E.
      Long-term results of splintage for mallet finger.
      (1996)
      11101221210154.17
      Lester et al
      • Lester B.
      • Jeong G.K.
      • Perry D.
      • Spero L.
      A simple effective splinting technique for the mallet finger.
      (2000)
      21110221221270.83
      Richards et al
      • Richards S.D.
      • Kumar G.
      • Booth S.
      • Naqui S.Z.
      • Murali S.R.
      A model for the conservative management of mallet finger.
      (2004)
      22110122211270.83
      Kalainov et al
      • Kalainov D.M.
      • Hoepfner P.E.
      • Hartigan B.J.
      • Carroll Ct
      • Genuario J.
      Nonsurgical treatment of closed mallet finger fractures.
      (2005)
      22220222222291.67
      Pike et al
      • Pike J.
      • Mulpuri K.
      • Metzger M.
      • Ng G.
      • Wells N.
      • Goetz T.
      Blinded, prospective, randomized clinical trial comparing volar, dorsal, and custom thermoplastic splinting in treatment of acute mallet finger.
      (2010)
      22222122222295.83
      O’Brien and Bailey
      • O'Brien L.J.
      • Bailey M.J.
      Single blind, prospective, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger.
      (2011)
      22222122222295.83
      Tocco et al
      • Tocco S.
      • Boccolari P.
      • Landi A.
      • et al.
      Effectiveness of cast immobilization in comparison to the gold-standard self-removal orthotic intervention for closed mallet fingers: a randomized clinical trial.
      (2013)
      22220222222291.67
      Altan et al
      • Altan E.
      • Alp N.B.
      • Baser R.
      • Yalcin L.
      Soft-tissue mallet injuries: a comparison of early and delayed treatment.
      (2014)
      22222122221291.67
      Saito and Kihara
      • Saito K.
      • Kihara H.
      A randomized controlled trial of the effect of 2-step orthosis treatment for a mallet finger of tendinous origin.
      (2016)
      222222222222100.00
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: Sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.
      Appendix CMethodological Quality of Conservative Versus Operative Studies Assessed by the Quality Appraisal Tool
      StudyItem Number; Item Evaluation Criteria
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.
      (Maximum = 2; Minimum = 0)
      Total (%)
      Authors (Year)123456789101112
      Auchincloss
      • Auchincloss J.M.
      Mallet-finger injuries: a prospective, controlled trial of internal and external splintage.
      (1982)
      22211122221283.33
      Wehbe and Schneider
      • Wehbe M.A.
      • Schneider L.H.
      Mallet fractures.
      (1984)
      22211021221275.00
      Groebli et al
      • Groebli Y.
      • Riedo L.
      • Della Santa D.
      • Marti M.C.
      Mallet fractures.
      (1987)
      22211221111275.00
      Lubahn
      • Lubahn J.D.
      Mallet finger fractures: a comparison of open and closed technique.
      (1989)
      22001220110150.00
      Renfree et al
      • Renfree K.J.
      • Odgers R.A.
      • Ivy C.C.
      Comparison of extension orthosis versus percutaneous pinning of the distal interphalangeal joint for closed mallet injuries.
      (2016)
      22211221221283.33
      Item 1: thorough literature review to define the research question; item 2: specific inclusion/exclusion criteria; item 3: specific hypotheses; item 4: appropriate scope of psychometric properties; item 5: sample size calculation/justification; item 6: appropriate retention/follow-up; item 7: authors referenced specific procedures for administration, scoring, and interpretation of procedures; item 8: measurement techniques were standardized; item 9: data were presented for each hypothesis; item 10: appropriate statistics—point estimate; item 11: appropriate statistical error estimates; item 12: valid conclusions and clinical recommendations.

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