Department of Orthopaedic Surgery, Kyung Hee University Hospital at Gangdong, School of Medicine, Kyung Hee University, #149, Sangil-dong, Gangdong-gu, Seoul 134-727, South Korea.
J Bone Joint Surg Am. 2011 May;93 Suppl 2:99-106. doi: 10.2106/JBJS.J.01771.
Loosening, femoral neck fracture, and metal ion release have been well documented after hip resurfacing arthroplasty, but impingement between the acetabular cup and the femoral neck has not. The goal of this study was to analyze radiographic findings that were presumed to represent impingement of the neck after hip resurfacing arthroplasty, and to describe the mechanism of impingement.
Of the 635 hips (579 patients) that underwent hip resurfacing arthroplasty between September 1998 and May 2008, forty hips (6.3%) with positive radiographic findings were available for this study. The mean age of the patients was 34.9 years and there were thirty-five men and five women. The average follow-up was sixty-eight months (twenty-four to 132 months). Radiographic evaluation included an analysis of neck-shaft angle, inclination of the acetabular cup, head-neck ratio, lateral protrusion of the cup, anterior protrusion of the cup, and stem angle to the axis of the femoral neck.
Impingement between the acetabular cup and the femoral neck occurred in 6.3% of hips and appeared at an average of seven months after surgery. There was no further change two years postoperatively. The impingement findings did not correlate with the clinical outcome, but all instances of impingement were located in the lateral or anterolateral part of the femoral neck along the arc from the center of the femoral head to the lateral edge of the socket. No significant factors were found to be related to the occurrence of impingement.
Femoral-neck impingement should be differentiated from notching, narrowing, stress-shielding, or osteolysis of the femoral neck. Although we found no significant factors to explain the impingement found in the hips in our study, it appears that repetitive extreme motion of the involved hip and malposition of the implants can cause impingement after hip resurfacing arthroplasty.
髋关节表面置换术后已充分记录到松动、股骨颈骨折和金属离子释放，但尚未记录到髋臼杯与股骨颈之间的撞击。本研究的目的是分析髋关节表面置换术后被认为代表股骨颈撞击的影像学发现，并描述撞击的机制。
1998 年 9 月至 2008 年 5 月期间进行髋关节表面置换术的 635 髋（579 例患者）中，有 40 髋（6.3%）存在阳性影像学发现，符合本研究要求。患者的平均年龄为 34.9 岁，男 35 例，女 5 例。平均随访时间为 68 个月（24-132 个月）。影像学评估包括颈干角、髋臼杯倾斜度、头颈比、杯外侧突出、杯前突和柄与股骨颈轴线的夹角。
髋臼杯与股骨颈之间发生撞击的发生率为 6.3%，平均发生于术后 7 个月。术后 2 年无进一步变化。撞击发现与临床结果无关，但所有撞击均位于股骨颈的外侧或前外侧部分，沿股骨头中心到髋臼外侧缘的弧形分布。未发现与撞击发生相关的显著因素。
股骨颈撞击应与股骨颈切迹、变窄、应力遮挡或骨溶解相鉴别。尽管我们在本研究中未发现髋关节撞击的显著因素，但髋关节表面置换术后反复的剧烈运动和植入物位置不当似乎会导致撞击。
