Journal of Hand Surgery
Volume 29, Issue 1 , Pages 144-147, January 2004

Radial nerve palsy associated with high-energy humeral shaft fractures 1

  • David Ring, MD

      Affiliations

    • Corresponding Author InformationReprint requests: David Ring, MD, Massachusetts General Hospital, Ambulatory Care Center 525, 15 Parkman St, Boston, MA 02114, USA
    • Harvard Medical School, Hand and Upper Extremity Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA
    • ,
  • Kingsley Chin, MD

      Affiliations

    • Harvard Combined Orthopaedic Residency, Boston, MA, USA
    • ,
  • Jesse B Jupiter, MD

      Affiliations

    • Harvard Medical School, Hand and Upper Extremity Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA

Received 20 February 2003; received in revised form 4 September 2003; accepted 4 September 2003.

Article Outline

Abstract 

Purpose

To determine whether the radial nerve should be explored when there is a complete sensory and motor deficit after a high-energy fracture of the humeral diaphysis.

Methods

Twenty-four patients aged 16 years or older with a high-energy, diaphyseal fracture of the humerus and complete motor and sensory radial nerve palsy were reviewed retrospectively. Eleven fractures were open—6 of these were part of a very complex upper-extremity injury (multiple ipsilateral fractures in 3 patients and near amputation in 3). All 11 patients with open fractures and 3 of 13 patients with closed injuries had radial nerve exploration.

Results

All 6 patients with a transected radial nerve had an open humerus fracture and were part of a complex upper-extremity injury. Five of 6 had primary repair of the radial nerve, and none recovered. All 8 intact explored nerves and 9 of 10 unexplored nerves recovered; the only nonrecovery occurred in a patient treated with closed intramedullary rod fixation who may have had iatrogenic nerve injury. The average time to initial signs of recovery was 7 weeks (range, 1–25 weeks). The average time to full recovery was 6 months (range, 1–21 months).

Conclusions

Transection of the radial nerve is usually associated with open fractures of the humerus that are part of a very complex upper-extremity injury. The results of primary nerve repair in this circumstance are poor, likely related to an extensive zone of injury and the need for nerve grafting. Intact nerves and nerve palsies that are part of a closed fracture nearly always recover, even after high-energy injuries. Because the first signs of nerve recovery and complete recovery of the nerve can be quite delayed, patience is merited before considering tendon transfers.

Keywords:  Radial nerve, nerve injury, fracture, humerus

 

The management of radial nerve dysfunction associated with fracture of the humeral diaphysis is disputed. In most cases the radial nerve is intact and the prognosis for complete or near complete recovery is good.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 Radial nerve transection is uncommon and is usually associated with an open fracture.4 Exploration of open fractures with radial nerve dysfunction is now generally agreed on, but all of the recommendations for exploring the radial nerve in closed injuries have been challenged, including those based on fracture location and morphology (the so-called Holstein-Lewis6 fracture) and the need to explore fractures associated with a change in nerve function after manipulation of the fracture.1, 11, 14, 17 Nonetheless, investigators continue to consider immediate exploration of closed injuries if there is a high-energy injury mechanism (Allen D, Mudgal CS, Patterson BM; Poster presented at the 16th Annual Meeting of the Orthopaedic Trauma Association, 2000 October 12–14, 2000, San Antonio, TX). We reviewed patients aged 16 years and older with complete radial nerve palsy who were treated at our institution after a high-energy fracture of the humeral diaphysis. We sought to determine whether the data support routine exploration of the radial nerve.

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Methods 

Forty-two patients with fracture of the diaphyseal humerus associated with dysfunction of the radial nerve treated at Massachusetts General Hospital between during a 12-year period were reviewed retrospectively under a protocol approved by the Human Research Committee. Only patients who received their initial fracture care at Massachusetts General Hospital were included—later referrals were excluded. Low-energy injuries (defined as simple falls from a standing height) were excluded. Twenty-four high-energy injuries satisfied the following inclusion criteria: (1) age 16 years or older at the time of injury, (2) complete sensory and motor nerve palsy, and (3) evaluation to complete nerve recovery or exploration or at least 2 years. Six patients were excluded because of inadequate follow-up time.

The parameters examined included the prevalence of lacerated nerves and unrecovered nerves, the times to the first signs of recovery and to full recovery, and the results of nerve and fracture treatment.

There were 18 men and 6 women with an average age of 27 years (range, 16–41 y). The mechanism of injury was a motor vehicle accident in 16 patients, a fall from a height in 4 patients, a crush injury in 2 patients, and an explosion and a gun shot wound, respectively, in 1 patient each. Eleven fractures were open (type 2 in 5 patients and type 3 in 6 patients according to the classification of Gustilo and Anderson18) and 13 were closed injuries.

Six of the 11 open injuries were extremely complex. Three were associated with multiple ipsilateral upper-extremity fractures, and 3 patients had associated injury to the brachial artery and the ulnar and/or median nerves and extensive muscle injury (near amputation).

Five fractures of the humerus were associated with diaphyseal forearm fractures (the so-called floating elbow). In 8 patients the fracture of the humerus was associated with injury to another limb or organ system (polytrauma). Nine fractures were isolated injuries (6 closed, 3 open).

All 11 patients with open fractures and 3 of 13 patients with closed injuries had radial nerve exploration. Three additional fractures were treated operatively but the nerve was not seen, including the only patient treated with (closed) intramedullary rod fixation. In the remaining 16 surgically treated patients, the humerus was repaired with a plate and screws. Seven patients were treated nonsurgically (functional bracing).

The fracture involved the proximal third of the humerus in 3 patients (2 spiral or oblique, 1 transverse), the middle third in 11 patients (3 comminuted, 3 spiral or oblique, 5 transverse), and the distal third in 10 patients (4 comminuted, 5 spiral or oblique, 1 transverse).

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Results 

Nerve exploration 

Six of 18 explored patients had nerve transection. This represented all 6 patients with complex open injuries (100%), 6 of 11 open fractures (54%), and 6 of 24 high-energy injuries (25%). Five transected nerves were repaired primarily using a microscope, and one with extensive crushing and avulsion of the median, ulnar, and radial nerves creating large defects was not repaired. None of the repaired nerves recovered.

One closed nerve injury that did not recover was explored at a second surgery for nonunion of the humerus fracture and was found to be severely damaged. This patient had been treated with closed intramedullary rod fixation—it is impossible to know whether nerve injury occurred at the time of the injury, during the dissection for nonunion, or, as has been previously reported,19 during the closed intramedullary rod insertion.

Nerve recovery—intact nerves and closed injuries 

All 8 patients with intact explored nerves and 9 of 10 patients with unexplored nerves (excluding the injury treated by closed intramedullary rod fixation) recovered. The average time to initial signs of recovery was 7 weeks (range, 1–25 weeks). Signs of recovery were delayed greater than 6 months in 1 patient. The average time to full recovery was 6 months (range, 1–21 months). Nerve conduction velocity and electromyogram studies were obtained in 7 patients at various times during recovery. Patients with no clinical signs of nerve recovery had no signs of recovery on nerve conduction velocity and electromyogram either.

Fracture outcomes 

Two patients required a second surgery for repeat internal fixation and autogenous cancellous bone grafting to obtain union; another was treated for a deep infection. All of the fractures eventually healed and the infection was quiescent at final evaluation.

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Discussion 

The study of radial nerve palsy associated with humeral shaft fractures is limited by the relative infrequency of this injury. As with prior studies of this injury we had to rely on retrospective review of medical records. This approach has obvious weaknesses, including more limited data regarding functional outcome—return of active wrist and digit extension against gravity was consistently recorded, but a more detailed evaluation was not reliably found. In this setting we have emphasized the clear findings that primary repair of lacerated radial nerves does not work and that intact radial nerves nearly always recover; we do not have sufficient detail in the data to determine the effect of injury type on time to recovery or other more specific questions.

Lacerated nerves 

Laceration of the radial nerve in association with a closed diaphyseal fracture of the humerus is unusual, even when the fracture is the result of a high-energy injury mechanism.2, 5, 7, 9, 11, 14, 15, 17 Radial nerve laceration is strongly associated with open fracture of the humerus.4, 11, 14 Our data suggest that only the highest-energy injuries—near amputations and extensive upper-extremity injuries—are associated with nerve laceration. Consequently, radial nerve laceration associated with fracture of the humerus is rarely a sharp, discrete injury. It is usually associated with extensive crush, stretch, and even avulsion of the nerve.20, 21

It is therefore not surprising that the results of primary suture of a lacerated radial nerve associated with fracture of the humerus are poor. None of the 5 repaired nerves in our series recovered. This stands in contrast to the better than 70% recovery of useful radial nerve function after later nerve grafting of injured radial nerves.20, 21 The only other series to document the results of primary repair of lacerated radial nerves in association with a humerus fracture observed somewhat better results.4

We recommend exploring the radial nerve only when the fracture of the humerus is open. When nerve exploration is performed, a direct lateral exposure of the humerus can improve access to both the proximal and distal ends of the nerve.22 Lacerated radial nerves should be repaired—at a second surgery when the wound is stable and clean and when the level of nerve injury (neuroma) is clearly demarcated—by cutting the nerve ends back to healthy nerve fascicles and grafting the resulting defects.20

Recovery of intact nerves 

Failure of an intact nerve (or a presumed intact nerve—closed injury) to recover is unusual. This was most common in the series of Bostman et al1 (15%), Packer et al9 (6%), and Sim et al16 (10%) but has been less than 5% in other series.2, 7, 11, 14, 15, 17 Our data support the fact that intact and presumed-intact (closed injury) radial nerves nearly always recover.

One must therefore question the importance of the findings of frequent nerve entrapment, contusion, crushing, etc in studies in which radial nerve fractures associated with humerus fractures were usually explored.5, 9, 10, 17 It is reasonable to assume that nonoperatively treated patients would have similar findings if they were operated on, and yet they nearly always recover.

Management of intact and presumed-intact nerves with delayed recovery 

Only a few radial nerve injuries treated closed or known to be intact on exploration will fail to recover. This relatively infrequent problem is the focus of the most difficult management issues. At what point should nerve exploration or nerve grafting be considered for a nerve that is slow to recover? Are there any diagnostic tests such as electromyogram that might help with this determination? What is the role of late nerve exploration and grafting—which is associated with uncertain and often incomplete recovery and requires an additional long period of disability while waiting for recovery—as compared with tendon transfers, which provide a predictably good restoration of hand opening but cannot restore fine independent extension movements?

Some of the observations in prior studies—many of which we also observed—are that (1) electromyogram findings parallel clinical findings and show signs of recovery no more than a month before it is clinically evident,10, 14 (2) the first signs of nerve recovery can be delayed longer than 6 months14, 15 (observed in 1 patient in this series); and (3) complete nerve recovery can take 2 years or more.15 In other words, although most patients recover quickly, a small subset of patients face a long period of disability waiting for full recovery and only a few never recover. Given these observations and the utility and predictable results of tendon transfers for radial nerve palsy, the patient’s needs and perspective will have a strong influence on management decisions. The role of nerve conduction velocity and electromyogram in the management of radial nerve palsy associated with a fracture of the humerus is uncertain because it cannot distinguish between a severed nerve and an unrecovered intact nerve and does not detect recovery much earlier than physical examination.

Patients who want to be splint-free and are satisfied with a hand that opens but does not have fine independent extension might consider tendon transfers if there is no recovery of nerve function within 6 months of the injury. Patients who are functional and comfortable wearing a low-profile radial nerve brace may be more patient during this period, and a period of 12 months may be worthwhile. Nerve exploration for possible grafting of nerve lesions may be most appropriate in patients who are motivated to put up with long recovery periods and an uncertain outcome in an attempt to regain independent finger extension and in patients with multiple nerve injuries in whom tendon transfer may be less feasible or less desirable. In these patients, nerve exploration might be considered if there are no signs of recovery by 6 months.

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References 

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  • 1 No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

PII: S0363-5023(03)00504-5

doi:10.1016/j.jhsa.2003.09.013

Journal of Hand Surgery
Volume 29, Issue 1 , Pages 144-147, January 2004

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