Ji Hyung-Min, Won Seok-Hyung, Han Jun, Won Ye-Yeon
Siheung 21C Hospital, Republic of Korea.
Department of Orthopaedics, Ajou University School of Medicine, Republic of Korea.
Injury. 2017 Jun;48(6):1170-1174. doi: 10.1016/j.injury.2017.03.022. Epub 2017 Mar 21.
Restoring preoperative horizontal femoral offset (FO) promised good functional outcome in patients receiving total hip arthroplasty. However, relatively little was known regarding the clinical relevance of restoring the offset in patients with bipolar hemiarthroplasty to treat displaced femoral neck fracture. Therefore, the objective of this study was to evaluate postoperative FO accurately and verify its relation with functional outcome.
One hundred elderly patients who received bipolar hemiarthroplasty to treat displaced femoral neck fracture were identified. Preoperative CT scanning of contralateral hip joint and reconstruction of images led to rotation-free FO. By referencing postoperative implant specification and comparing to measured values in Picture Archive and Communication System, rotation-free postoperative FO and the amount of change were acquired. Postoperative Harris Hip Score (HHS) and Modified Barthel Index (MBI) were evaluated to measure functional outcome at 12-month after the surgery. Patients with significant FO change were identified. Multiple regression analysis was conducted to determine if the FO change might independently affect the outcome regardless of confounding factors.
The mean preoperative offset was 37.4±2.5 increased by 12.7±9.6% after the surgery. Only 25.0% of postoperative offset after hemiarthroplasty was changed within ±5% of preoperative offset. A total of 45.0% of postoperative offset changed within ±10% while 77.0% of postoperative offset changed within ±20%. 23% of patients whose FO changed more than 20% showed significantly worse outcome score than the patients whose FO change remained within ±20% of initial value. Mean MBI and HHS were negatively correlated with FO change. After adjusting for confounding factors, significant correlation remained between modification of FO and MBI, but not between FO change and HHS (B=4.576; β=0.235; 95% confidence interval of B: 0.534 to 8.135).
FO was not properly restored in 23% of subjects receiving bipolar hemiarthroplasty due to femoral neck fracture. FO restoration independently predicted fair MBI after the surgery. Therefore, surgeons should pay attention to restoring FO with meticulous templating.
恢复术前股骨水平偏移（FO）有望使接受全髋关节置换术的患者获得良好的功能预后。然而，对于采用双极半髋关节置换术治疗移位型股骨颈骨折的患者，恢复偏移的临床相关性相对知之甚少。因此，本研究的目的是准确评估术后FO，并验证其与功能预后的关系。
纳入100例接受双极半髋关节置换术治疗移位型股骨颈骨折的老年患者。对健侧髋关节进行术前CT扫描并重建图像，得出无旋转的FO。通过参考术后植入物规格并与图像存档与通信系统中的测量值进行比较，获得无旋转的术后FO及其变化量。在术后12个月评估Harris髋关节评分（HHS）和改良Barthel指数（MBI）以衡量功能预后。确定FO变化显著的患者。进行多元回归分析，以确定FO变化是否可能独立于混杂因素影响预后。
术前平均偏移为37.4±2.5，术后增加了12.7±9.6%。半髋关节置换术后只有25.0%的术后偏移在术前偏移的±5%范围内变化。共有45.0%的术后偏移在±10%范围内变化，而77.0%的术后偏移在±20%范围内变化。FO变化超过20%的患者中有23%的预后评分明显低于FO变化保持在初始值±20%范围内的患者。平均MBI和HHS与FO变化呈负相关。在调整混杂因素后，FO的改变与MBI之间仍存在显著相关性，但FO变化与HHS之间不存在显著相关性（B=4.576；β=0.235；B的95%置信区间：0.534至8.135）。
23%因股骨颈骨折接受双极半髋关节置换术的患者中，FO未得到妥善恢复。FO的恢复独立预测术后良好的MBI。因此，外科医生应通过细致的模板操作注意恢复FO。
