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The Use of Distal Ulnar Hounsfield Units to Predict Future Fragility Fracture Risk

  • Theodora C. Dworak
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD
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  • Scott C. Wagner
    Correspondence
    Corresponding author: Scott C. Wagner, MD, Department of Orthopaedics, Rothman Institute at Thomas Jefferson University, 925 Chestnut Street, Philadelphia, PA 19107.
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD

    Department of Orthopaedics, Rothman Institute at Thomas Jefferson University, Philadelphia, PA
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  • Kyle E. Nappo
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD
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  • George C. Balazs
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD
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  • Patrick D. Grimm
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD
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  • Donald F. Colantonio
    Affiliations
    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD
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  • Scott M. Tintle
    Affiliations
    Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD

    Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD

    Department of Orthopaedic Surgery, University of Pennsylvania Health System, Philadelphia, PA
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      Purpose

      Distal ulnar Hounsfield unit (HU) measurements obtained from computed tomography (CT) scans of the wrist can be used to accurately screen for low bone mineral density. It is unknown whether HU measurements can also predict the risk of future fragility fractures. Therefore, the purpose of this study was to determine if the HU values of the distal ulna correlate to fragility fracture risk.

      Methods

      An electronic database of radiographs at a single institution was searched for all wrist CT scans, obtained for any reason, between January 1, 2002, and December 31, 2008, to allow a minimum of 5-year follow-up. Manual measurement of HU on sequential coronal CT slices of the distal ulnar head was taken, and mean values were recorded. Previously determined cutoff values for the diagnosis of low bone mineral density were implemented to stratify patients as at risk or not at risk for future fragility fracture. Medical records were then manually reviewed for the occurrence of any future fragility fracture (hip, spine, proximal humerus, or rib).

      Results

      There were 161 CTs in 157 patients and 34 fragility fractures in 21 patients, with a prevalence of 13.4%. The mean HU in the fragility fracture group was significantly lower (134.2 vs 197.1 HU). The percentage of low HU patients with fragility fractures was significantly higher (22.7% vs 3.8%). The odds ratio for fragility fracture in the low HU group was 7.4 (95% confidence interval, 2.1–26.2). Using previously determined cutoff values, the sensitivity and specificity of distal ulna HU values for identifying patients who would sustain at least 1 future fragility fracture were 85.7% and 55.2%, respectively.

      Conclusions

      Patients with low distal ulnar HU were significantly more likely to sustain a subsequent fragility fracture. A determination of distal ulnar HUs represents a quick, simple tool to identify patients potentially at risk for fragility fractures.

      Type of study/level of evidence

      Prognostic IV.

      Key words

      Osteoporosis is defined as decreased bone mineral density (BMD) in the setting of disrupted bone architecture.
      • Nelson H.D.
      • Haney E.M.
      • Dana T.
      • Bougatsos C.
      • Chou R.
      Screening for osteoporosis: an update for the U.S. Preventive Services Task Force.
      • Gehrig L.M.
      • Collinge C.
      • Kaufman J.
      • Lane J.M.
      • O'Connor M.I.
      • Tosi L.L.
      Osteoporosis: management and densitometry for orthopaedic surgeons.
      Patients diagnosed with osteoporosis are at increased risk for fragility fractures of the hip, forearm, spine, and ribs.
      • Kim T.I.
      • Choi J.H.
      • Kim S.H.
      • Oh J.H.
      The adequacy of diagnosis and treatment for osteoporosis in patients with proximal humeral fractures.
      These fractures come with a substantial economic burden because the median inpatient cost for patients sustaining fragility fractures is reported to be 2.7 times greater than for preventive measures in prefracture patients, or matched patients without fractures.
      • Budhia S.
      • Mikyas Y.
      • Tang M.
      • Badamgarav E.
      Osteoporotic fractures: a systematic review of U.S. healthcare costs and resource utilization.
      These costs are expected to rise to 25.3 billion dollars by the year 2025 as a result of the aging population, and an increasing proportion of males who are predicted to be affected by osteoporosis.
      • Budhia S.
      • Mikyas Y.
      • Tang M.
      • Badamgarav E.
      Osteoporotic fractures: a systematic review of U.S. healthcare costs and resource utilization.
      The 5-year mortality after fragility fracture is significantly greater than the mortality rates in age-matched populations.
      • Bliuc D.
      • Nguyen N.D.
      • Milch V.E.
      • Nguyen T.V.
      • Eisman J.A.
      • Center J.R.
      Mortality risk associated with low-trauma osteoporotic fracture and subsequent fracture in men and women.
      Previous efforts for preventing fragility fractures have focused on implementing scoring systems such as Fracture Risk Assessment Tool (FRAX) or qualitative ultrasound (QUS); however, such scoring systems typically require multiple data points.
      • Villa P.
      • Lassandro A.P.
      • Moruzzi M.C.
      • et al.
      A non-invasive prevention program model for the assessment of osteoporosis in the early postmenopausal period: a pilot study on FRAX and QUS tools advantages.
      • Marques A.
      • Ferreira R.J.
      • Santos E.
      • Loza E.
      • Carmona L.
      • da Silva J.A.
      The accuracy of osteoporotic fracture risk prediction tools: a systematic review and meta-analysis.
      • Cormier C.
      • Koumakis E.
      • Souberbielle J.C.
      Choosing the tool for osteoporosis risk prediction.
      Recent literature has explored the evaluation of BMD on routine computed tomography (CT) scans of the spine, abdomen, and wrist obtained for reasons other than BMD evaluation.
      • Marinova M.
      • Edon B.
      • Wolter K.
      • Katsimbari B.
      • Schild H.H.
      • Strunk H.M.
      Use of routine thoracic and abdominal computed tomography scans for assessing bone mineral density and detecting osteoporosis.
      • Lee S.
      • Chung C.K.
      • Oh S.H.
      • Park S.B.
      Correlation between bone mineral density measured by dual-energy X-ray absorptiometry and Hounsfield units measured by diagnostic CT in lumbar spine.
      • Pickhardt P.J.
      • Pooler B.D.
      • Lauder T.
      • del Rio A.M.
      • Bruce R.J.
      • Binkley N.
      Opportunistic screening for osteoporosis using abdominal computed tomography scans obtained for other indications.
      • Schreiber J.J.
      • Anderson P.A.
      • Rosas H.G.
      • Buchholz A.L.
      • Au A.G.
      Hounsfield units for assessing bone mineral density and strength: a tool for osteoporosis management.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      • Johnson C.C.
      • Gausden E.B.
      • Weiland A.J.
      • Lane J.M.
      • Schreiber J.J.
      Using Hounsfield units to assess osteoporotic status on wrist computed tomography scans: comparison with dual energy X-ray absorptiometry.
      Hounsfield unit (HU) measurements of the lumbar spine correlate with BMD, thus providing a simple tool for screening for patients who may benefit from a further work-up of BMD or even medical treatment.
      • Wagner S.C.
      • Formby P.M.
      • Helgeson M.D.
      • Kang D.G.
      Diagnosing the undiagnosed: osteoporosis in patients undergoing lumbar fusion.
      • Schreiber J.J.
      • Kamal R.N.
      • Yao J.
      Simple assessment of global bone density and osteoporosis screening using standard radiographs of the hand.
      Similarly, recent literature has compared HU values of distal radius CT scans from distal radius fracture patients with controls and found significantly lower distal radius HU in the fracture group.
      • Schreiber J.J.
      • Gausden E.B.
      • Anderson P.A.
      • Carlson M.G.
      • Weiland A.J.
      Opportunistic osteoporosis screening–gleaning additional information from diagnostic wrist CT scans.
      Two recent publications compared dual-energy x-ray absorptiometry (DXA) information with HU measurements in the distal ulna
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      and the capitate and significant relationships between HU values on wrist CT and BMD, as determined by the DXA scan, were found.
      • Johnson C.C.
      • Gausden E.B.
      • Weiland A.J.
      • Lane J.M.
      • Schreiber J.J.
      Using Hounsfield units to assess osteoporotic status on wrist computed tomography scans: comparison with dual energy X-ray absorptiometry.
      However, the utility of these measurements in predicting susceptibility for future fragility fractures has never been evaluated.
      The purpose of the present study was to determine if HU values of the distal ulna predict future fragility fracture risk by applying previously established screening HU cutoff values to a sample of patients with wrist CT scans, obtained for various indications. We hypothesize that CT scans of the distal radius, often obtained as part of a routine wrist pain work-up, could be used as a screening tool for osteoporosis and identify patients at risk for fragility fracture (defined as fractures of the hip, spine, proximal humerus, or ribs) over a minimum of 5 years of follow up.

      Methods

      After institutional review board approval, our institution’s Picture Archiving and Communication System (IMPAX) was queried for wrist CT scans completed between January 2002 and December 2008. We began the analysis in 2014, thereby ensuring at least 5 years of follow-up after the CT scan. Patients were excluded from the study if they were below 45 years of age or had incomplete data regarding imaging or BMD data. We also excluded patients who had less than 12 months of continuous documented clinical follow-up from the time of their CT scan. We assumed that patients routinely received health care in our closed military health care system if they had follow-up within the first 12 months following their CT scan. The reason for this assumption is that in the military health care system, it is possible to obtain authorization for care at a civilian provider if appropriate services are not available at the nearest military treatment facility. If a patient did not have complete follow-up records in the first year after the CT scan, we assumed that he/she was receiving at least some level of treatment outside the military, and thus had to be excluded. If, however, the patient had continuous, documented follow-up for a minimum of 12 months, we assumed that all care was being received within the military system, and any subsequent fragility fractures would be documented. All patients’ medical records were then reviewed at a minimum of 5-year follow-up, as noted above. HU measurements were performed using the IMPAX software measured on sequential slices of the CT scan using a best-fit circle to the area of the distal ulna, as previously described by Wagner et al.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      Patients’ electronic medical records were reviewed to determine patients’ age and sex. In addition, the radiology portion of the chart was reviewed to determine if the patients sustained any subsequent fragility fractures dated after their original wrist CT scan. The location, laterality, and mechanism of injury for these fractures were determined by the chart review.

      Risk analysis

      A previous study directly comparing HU values of the distal ulna and forearm DXA T-scores determined that in patients with forearm T-scores consistent with low BMD, the minimum screening HU threshold was below 146 HU.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      Using the techniques previously described,
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      we measured distal ulnar HU and applied these cutoff values to categorize our patients into the following groups: within normal limits (WNL) HU (patients with HU greater than or equal to 146) and low HU (patients with HU values less than 146). We then determined the number of fragility fractures in each group to subsequently calculate sensitivity, specificity, and negative predictive values of this measurement tool in its ability to predict future fragility fracture over a minimum of 5 years of follow-up (Fig. 1).
      Figure thumbnail gr1
      Figure 1A representative example of the technique for measuring distal ulnar Hounsfield units, as described by Wagner et al.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      A-C Three sequential coronal computed tomography (CT) scan slices at the level of the distal radial-ulnar joint are used, with the circular region of interest being localized to the cancellous area within the distal ulnar head. A mean is calculated for the 3 measurements, a confidence range is generated, and the 95% confidence value is subtracted to identify a minimum value that is used as the cutoff for the patient.

      Statistical analysis

      A 2-tailed t-test was used to compare mean ages and HU values between fracture and nonfracture groups. Chi-square analysis was used to compare categorical values between these same groups. Furthermore, an odds ratio was calculated to compare the comparative likelihood of having a future fragility fracture if the distal HU measurement was below 146 HU.

      Source of funding

      There was no external funding for this project.

      Results

      One hundred sixty-one CT scans were reviewed in 157 patients, of whom 83 (52.9%) were female and 74 (47.1%) were male. Average follow-up was 9.3 years, with a minimum of 5 years. The average age of the patients in the fragility fracture group was higher than the nonfracture group, but this finding did not reach statistical significance (59.7 years vs 54.9 years, respectively; P = .06). However, the percentage of female patients in the fracture group was significantly greater than that in the nonfracture group, 73.0% vs 49.6% (P < .05).

      Indications for CT

      CT scans of the wrist were obtained for distal radius fractures (DRF) 57.5% of the time, with the remaining scans obtained for other indications (Table 1). When including patients who received bilateral wrist CT scans only once, there were 80 individual patients with distal radius fractures (51.0%) and 77 (49.0%) with other indications for the scan. The mean age of patients in the DRF group was 56.3 years and was 55.0 years in the non-DRF group. We were unable to show significant differences in age, male to female ratio, or the percentage worked up for osteoporosis with DXA scans: 42.2% vs 30.8% (P > .05), respectively. In addition, there was no difference in the percentage of subsequent fragility fractures between the distal radius fracture and no fracture groups: 16.3% vs 16.9%. However, there was a significantly lower mean HU in the DRF group (170.9HU vs 207.2HU) than in the non-DRF group (P < .05).
      Table 1Indication for Wrist CT Scan (n = 160)
      IndicationN (%)
      Distal radius fracture92 (57.5%)CT acutely after trauma/fall (n = 126)
      Scaphoid or rule out scaphoid fracture20 (12.5%)
      Triquetral avulsion fracture4 (2.5%)
      Isolated ulna fracture4 (2.5%)
      Hamate fracture3 (1.9%)
      Base of fifth metacarpal fracture2 (1.3%)
      Capitate fracture1 (0.6%)
      Wrist pain18 (11.3%)CT not after acute trauma/fall (n = 34)
      Arthritis/SLAC wrist5 (3.1%)
      Follow-up distal radius fracture fixation2 (1.3%)
      Postoperative from fusion procedure2 (1.3%)
      Bone or mass evaluation2 (1.3%)
      Distal radius fracture malunion1 (0.6%)
      Distal radioulnar joint assessment1 (0.6%)
      Kienbock’s disease1 (0.6%)
      Follow-up SL reconstruction1 (0.6%)
      Follow-up scaphoid fracture fixation1 (0.6%)
      CT, computed tomography, SL, scapholunate; SLAC, scapholunate advanced collapse.

      Subsequent fragility fractures

      Thirty-four subsequent fragility fractures, which include hip, spine, rib, or proximal humerus (excluding those distal radius fractures sustained before the initial CT scan), were found in 21 patients for an overall prevalence of 13.4% over a minimum of 5 years of follow-up (Table 2). The mean distal ulnar HU value obtained on CT scan before the subsequent fragility fracture was significantly lower in the fragility fracture group than in the nonfracture group, 134.2 vs 197.1 HU (P < .05). The rate of osteoporosis work-up, which we defined as the percentage of patients obtaining a DXA scan at any point after the CT, was significantly higher in the fragility fracture group compared with the nonfracture group, 52.4% vs 32.4% (P = .05).
      Table 2Groups Based on Distal Ulna Hounsfield Unit (HU) Measurement
      VariableHU ≤ 146HU > 146P-value
      No. of patients79 (50.3%)78 (49.7%)
      No of fragility fractures/no. of patients (%)29, 18 (22.7%)5, 3 (3.8%)<.001
      Indicates statistical significance (P < .05).
      Odds ratio of future fracture (95% confidence interval)7.4 (2.1-26.2)0.12 (0.04-0.35)<.05
      Indicates statistical significance (P < .05).
      Indicates statistical significance (P < .05).

      Hounsfield stratification

      As noted previously, a prior study determined a minimum distal ulnar HU threshold for the screening of low BMD and osteoporosis. Using these cutoff values, 49.7% of the patients probably had BMD WNL, and 50.3% would be considered at risk for low BMD. The percentage of fragility fractures was higher in the low HU group compared with the WNL group: 24.1% vs 3.8% (P < .05). The odds ratio for fragility fractures in the low HU group was calculated to be 7.4 (95% confidence interval, 2.1–26.2; P < .05) (Table 2). Of the 21 patients with fragility fractures, 90.5% (19/21) had minimum screening HU values below our cutoff, compared with 57.4% in the nonfracture group, yielding a sensitivity of 85.7% and specificity of 55.2%. In our sample, with a future fragility fracture prevalence of 13.4%, the positive and negative predictive values for distal ulnar HU were 22.8% and 96.2% for future fragility fractures, respectively.

      Discussion

      We found that patients with fragility fractures of the hip, spine, proximal humerus, or ribs had significantly lower distal ulnar HU measurements than those without fragility fractures, when using the measurement technique described by Wagner et al.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      Although a simple and straightforward evaluation of BMD would be ideal, possible surrogate measures for BMD such as distal ulnar HU would be highly beneficial to the hand surgeon, as there is a myriad of evidence suggesting that orthopedic patients often are not appropriately referred for BMD evaluation after fragility fractures.
      • Baba T.
      • Hagino H.
      • Nonomiya H.
      • et al.
      Inadequate management for secondary fracture prevention in patients with distal radius fracture by trauma surgeons.
      • Balasubramanian A.
      • Tosi L.L.
      • Lane J.M.
      • Dirschl D.R.
      • Ho P.R.
      • O'Malley C.D.
      Declining rates of osteoporosis management following fragility fractures in the U.S., 2000 through 2009.
      • Neuman M.D.
      • Kennelly A.M.
      • Tosi L.L.
      Breakout session: sex/gender and racial/ethnic disparities in the care of osteoporosis and fragility fractures.
      CT scans of the wrist are commonly performed to evaluate distal radius fractures or for other indications, and prior studies have found that low HU values of the distal ulna and capitate are associated with decreased BMD of the forearm and hip, as well as the lumbar spine.
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      • Johnson C.C.
      • Gausden E.B.
      • Weiland A.J.
      • Lane J.M.
      • Schreiber J.J.
      Using Hounsfield units to assess osteoporotic status on wrist computed tomography scans: comparison with dual energy X-ray absorptiometry.
      • Bevevino A.J.
      • Dickens J.F.
      • Potter B.K.
      • Dworak T.
      • Gordon W.
      • Forsberg J.A.
      A model to predict limb salvage in severe combat-related open calcaneus fractures.
      There is some suggestion in the literature that wrist CT scans can thus be used as a screening tool for BMD assessment, but to our knowledge, no prior study has evaluated the application of HU cutoff values to a population to assess the risk of fragility fracture. We found that patients with low distal ulnar HU, below our predetermined cutoff values, were more likely to sustain a subsequent fragility fracture. Previous studies have suggested that a history of prior distal radius fracture is a predictive factor for subsequent fracture.
      • Beattie K.
      • Adachi J.
      • Ioannidis G.
      • et al.
      Estimating osteoporotic fracture risk following a wrist fracture: a tale of two systems.
      • Cuddihy M.T.
      • Gabriel S.E.
      • Crowson C.S.
      • O'Fallon W.M.
      • Melton III, L.J.
      Forearm fractures as predictors of subsequent osteoporotic fractures.
      Interestingly, we were unable to show a difference in the rate of subsequent fragility fractures between the distal radius fracture group and no fracture groups, and there was a low rate of osteoporosis work-up in the group that had sustained a distal radius fracture as the initial indication for the CT scan.
      We found that the previously determined HU cutoff value of 146 HU had a negative predictive value of 96.2% and a sensitivity of 85.7% for future fragility fracture risk. A previous study compared FRAX with QUS for diagnostic algorithms; both had lower negative predictive values, 43.6% and 45.1%, respectively.
      • Villa P.
      • Lassandro A.P.
      • Moruzzi M.C.
      • et al.
      A non-invasive prevention program model for the assessment of osteoporosis in the early postmenopausal period: a pilot study on FRAX and QUS tools advantages.
      There was little improvement in the prediction when FRAX and QUS were used in combination (PPV 82.9% and NPV 39.0%).
      Schreiber et al
      • Schreiber J.J.
      • Gausden E.B.
      • Anderson P.A.
      • Carlson M.G.
      • Weiland A.J.
      Opportunistic osteoporosis screening–gleaning additional information from diagnostic wrist CT scans.
      recently evaluated the HU of patients with distal radius fractures, and compared them with age-matched controls. They found the fracture group to have a significantly lower HU value than the nonfracture group in multiple locations in the wrist, and subsequently recommended a distal radius HU cutoff value of 218 for females and 246 for males.
      • Schreiber J.J.
      • Gausden E.B.
      • Anderson P.A.
      • Carlson M.G.
      • Weiland A.J.
      Opportunistic osteoporosis screening–gleaning additional information from diagnostic wrist CT scans.
      However, this value was not correlated with actual DXA data or future fracture risk. In a follow-up paper, they found that HU values at the capitate were significantly correlated with central BMD, and recommended using wrist CT scans for BMD screening.
      • Johnson C.C.
      • Gausden E.B.
      • Weiland A.J.
      • Lane J.M.
      • Schreiber J.J.
      Using Hounsfield units to assess osteoporotic status on wrist computed tomography scans: comparison with dual energy X-ray absorptiometry.
      These findings were similar to those of Wagner et al,
      • Wagner S.C.
      • Dworak T.
      • Grimm P.
      • Balazs G.C.
      • Tintle S.
      Measurement of distal ulnar Hounsfield units accurately predicts bone mineral density of the forearm.
      but neither of these previous studies evaluated the impact of HU measurements on ascertaining fragility fracture risk. The current study shows an association with decreased distal ulnar HU and fragility fracture risk.
      Our study is limited in that it is a retrospective review of patients completed at a single institution. We had to assume that our patients, being part of the military health care system, had complete follow-up documentation, though it is possible that some patients subsequently were referred into other local civilian systems and spuriously decreased our observed fragility fracture prevalence. However, we did attempt to minimize this potential confounder by excluding any patients without continuous orthopedic follow-up for the 12 months subsequent to the initial CT scan. The present study includes both patients with wrist fracture and those without fractures; however, those patients obtaining a CT scan of the wrist had some clinical complaint that warranted a CT scan and thus may not be considered true asymptomatic controls. In addition, there were significantly more females who sustained a fragility fracture than males, and the prevalence of fragility fractures may be different in the civilian population, which can affect the positive and negative predictive values. Furthermore, abnormal bone is only one part of a multifactorial etiology contributing to fragility fracture risk. Although our method only takes into account this one aspect, an advantage is that it proves to have similar predictive values as other described methods without the input of a detailed patient’s history.
      In addition, it is perhaps most important to note that because of the high prevalence of previous distal radius fractures in our study sample, which was the original indication for a wrist CT scan, the sensitivity and specificity determined are likely spuriously elevated. It is possible that the predictive capacity of distal ulnar HU as a screening mechanism for patients at risk for fragility fractures would be decreased across a normal population. In our comparison of the groups with and without distal radius fractures, we found that the rate of work-up for osteoporosis was only 42% in the DRF group, and though higher than the non-DRF group (31%), is still alarmingly low.
      The determination of distal ulnar HUs is a relatively quick tool to accurately identify patients at risk for fragility fractures following routine work-up of wrist pathology with the CT scan. The technique requires no additional testing or manipulation of the images and can easily be determined during the work-up of patients with or without distal radius fractures. This method can be used in combination with, and in addition to, traditional screening methods for osteoporosis to help improve the diagnosis and treatment of those patients most at risk for future fragility fracture.

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