von Knoch Marius, Berry Daniel J, Harmsen W Scott, Morrey Bernard F
Mayo Clinic, 200 First Street S.W., Rochester, MN 55902, USA.
J Bone Joint Surg Am. 2002 Nov;84(11):1949-53. doi: 10.2106/00004623-200211000-00007.
Some patients have a dislocation for the first time many years after a total hip arthroplasty, but little is known about the risk factors and outcomes associated with late dislocation. The purposes of this study were (1) to determine the prevalence of late dislocation after total hip arthroplasty, (2) to characterize demographic and other factors associated with such late dislocations, and (3) to report the outcomes of such late dislocations.
Between 1969 and 1995, 19,680 primary total hip arthroplasties were performed in 15,964 patients at our institution. According to a prospective surveillance protocol, the patients were followed routinely at regular intervals and were specifically queried at each time-point about whether (and, if so, when) the hip had dislocated. First dislocations that occurred five years or more after the operation were defined as late dislocations.
Five hundred and thirteen (2.6%) of the 19,680 hips dislocated. Of the 513 hips, 165 (0.8% of the entire cohort; 32% of the dislocated hips) first dislocated five or more years after the primary arthroplasty. The median time until the occurrence of these late dislocations was 11.3 years (range, five to 24.9 years) after the operation. Late dislocation was more frequent than early dislocation in women (p = 0.03), and late dislocation was associated with a younger age at the time of the primary total hip arthroplasty (median, sixty-three years) than was early dislocation (median, sixty-seven years) (p = 0.02). Clinical factors associated with late dislocation included previous subluxations without dislocation in twenty patients, a substantial episode of trauma in eleven patients, and onset of marked cognitive or motor neurologic impairment in eleven patients. Radiographically, the late dislocation occurred in association with polyethylene wear of >2 mm in eighteen hips, with implant loosening with migration or a change in position in eight, and with initial malposition of the acetabular implant (anteversion of <0 degrees or >30 degrees or abduction of >55 degrees) in thirty. Late dislocation recurred in ninety (55%) of the 165 hips and was treated with a reoperation in fifty-five hips (33% of the hips with late dislocation; 61% of the hips with recurrent dislocation).
Late dislocation is more common than was previously thought. Several separate processes, some distinct from those associated with early dislocation, can lead to late dislocation. Late dislocation can occur in association with a long-standing problem with the prosthesis that manifests late (such as malposition of the implant or recurrent subluxation), it can occur in association with a new problem (such as neurologic decline, an episode of trauma, or polyethylene wear), or it can occur in association with any combination of these factors. The likelihood of the first late dislocation recurring is high.
一些患者在全髋关节置换术后多年首次发生脱位，但对于晚期脱位的危险因素及相关预后知之甚少。本研究的目的是：（1）确定全髋关节置换术后晚期脱位的发生率；（2）描述与此类晚期脱位相关的人口统计学及其他因素；（3）报告此类晚期脱位的预后情况。
1969年至1995年间，我们机构为15964例患者实施了19680例初次全髋关节置换术。根据前瞻性监测方案，对患者进行定期常规随访，并在每个时间点专门询问髋关节是否（若有，何时）发生脱位。将术后五年或更长时间发生的首次脱位定义为晚期脱位。
19680例髋关节中有513例（2.6%）发生脱位。在这513例脱位髋关节中，165例（占整个队列的0.8%；占脱位髋关节的32%）在初次置换术后五年或更长时间首次发生脱位。这些晚期脱位发生的中位时间为术后11.3年（范围为5至24.9年）。女性晚期脱位比早期脱位更常见（p = 0.03），与早期脱位相比，晚期脱位与初次全髋关节置换时年龄较轻（中位年龄63岁）相关（早期脱位中位年龄67岁）（p = 0.02）。与晚期脱位相关的临床因素包括20例患者既往有半脱位但未脱位、11例患者有严重创伤事件以及11例患者出现明显认知或运动神经功能障碍。影像学检查显示，18例髋关节晚期脱位与聚乙烯磨损>2mm有关，8例与植入物松动伴移位或位置改变有关，30例与髋臼植入物初始位置不当（前倾角<0度或>30度或外展角>55度）有关。165例髋关节中有90例（55%）晚期脱位复发，55例髋关节（占晚期脱位髋关节的33%；占复发脱位髋关节的61%）接受了再次手术治疗。
晚期脱位比之前认为的更常见。几个不同的过程，其中一些与早期脱位相关的过程不同，可导致晚期脱位。晚期脱位可与假体长期存在的问题（如植入物位置不当或反复半脱位）后期表现相关，可与新出现的问题（如神经功能衰退、创伤事件或聚乙烯磨损）相关，也可与这些因素的任何组合相关。首次晚期脱位复发的可能性很高。
