Dworak Theodora C, Wagner Scott C, Nappo Kyle E, Balazs George C, Grimm Patrick D, Colantonio Donald F, Tintle Scott M
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, 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.
J Hand Surg Am. 2018 Nov;43(11):1010-1015. doi: 10.1016/j.jhsa.2018.04.017. Epub 2018 Jun 8.
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.
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).
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.
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.
通过腕部计算机断层扫描（CT）获得的尺骨远端亨氏单位（HU）测量值可用于准确筛查低骨密度。目前尚不清楚HU测量值是否也能预测未来脆性骨折的风险。因此，本研究的目的是确定尺骨远端的HU值是否与脆性骨折风险相关。
在一个机构的电子数据库中搜索2002年1月1日至2008年12月31日期间因任何原因进行的所有腕部CT扫描，以便进行至少5年的随访。在尺骨远端头部的连续冠状CT切片上手动测量HU，并记录平均值。采用先前确定的低骨密度诊断临界值，将患者分为有未来脆性骨折风险或无风险。然后人工查阅病历，了解是否发生任何未来脆性骨折（髋部、脊柱、肱骨近端或肋骨）。
157例患者中有161次CT扫描，21例患者发生34次脆性骨折，患病率为13.4%。脆性骨折组的平均HU显著较低（134.2对197.1 HU）。发生脆性骨折的低HU患者百分比显著更高（22.7%对3.8%）。低HU组脆性骨折的比值比为7.4（95%置信区间，2.1 - 26.2）。使用先前确定的临界值，尺骨远端HU值识别至少发生1次未来脆性骨折患者的敏感性和特异性分别为85.7%和55.2%。
尺骨远端HU低的患者发生后续脆性骨折的可能性显著更高。测定尺骨远端HU是一种快速、简单的工具，可用于识别有脆性骨折潜在风险的患者。
研究类型/证据水平：预后性IV级。
