Late dislocation is associated with recurrence after total hip arthroplasty

Purpose

This study was conducted to examine the risk factors for recurrent dislocation after total hip arthroplasty (THA) and test the hypothesis that late dislocations are associated with recurrence.

Methods

A total of 1,250 hips in 1,017 patients were retrospectively reviewed. All operations were performed through the posterolateral approach with posterior soft tissue repair. An early or late dislocation was defined as a dislocation occurring before or after one year postoperatively, respectively.

Results

Dislocation occurred in 36 hips (2.9 %) and 20 of them experienced recurrence. Recurrent dislocations were observed in ten out of 25 hips (40.0 %) with early dislocation; however, ten out of 11 hips (90.9 %) with late dislocation experienced recurrence (p = 0.0046). Multivariate analysis revealed that late dislocation was significantly associated with recurrence with odds ratio of 5.94 per year. Seven in 20 hips with recurrent dislocation required surgical treatment.

Conclusion

Late dislocation significantly contributed to the development of recurrent dislocations.     

Late dislocation after total hip arthroplasty

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.     

Early dislocation after total hip arthroplasty

Background The average incidence of dislocation after total hip arthroplasty is approximately 3%. However, the choice of surgical approach can affect the rate of postoperative dislocation. A 5.8% dislocation rate has previously been reported when a posterolateral approach was used compaired with 2.3% when an anterolateral approach was used. The aim of this study was therefore to assess the dislocation rate after total hip replacement with the posterolateral approach.Methods: Between January 1992 and December 1998, a posterolateral approach was used for 427 consecutive primary total hip replacements. There were 291 women and 136 men. The average age of the women was 71 years (range 40–91 years) and the average age of the men was 65 years (range 34–86 years). The one-year dislocation rate was recorded.Results: A total of 24 hip replacements (6 in men and 18 in women) dislocated. The one-year dislocation rate was 6/136 = 4.4% for men and 18/291 = 6.2% for women. The overall one-year dislocation rate was therefore 24/427 = 5.6%. The average delay between the operation and the dislocation was 7 weeks (range 1 day to 1 year).Conclusions Our results seem to confirm a high postoperative dislocation rate when the posterolateral approach is used. Most dislocations occured within the first 3 months after the surgery. An unexpected annual variation in the dislocation rate was found. No explanations was found for this variation.     

Early dislocation after total hip arthroplasty

We studied prospectively 499 cases of primary total hip arthroplasty done through an anterolateral approach to establish the early dislocation rate when restrictions on postoperative mobilization were not imposed. There were 3 early dislocations (within 6 weeks of surgery). All were reduced closed, and every patient subsequently achieved a stable hip without further intervention. Our results suggest that a low early dislocation rate can be achieved using an anterolateral approach without the need to restrict patients' postoperative mobilization. It may not be appropriate, however, to remove these restrictions when using other surgical approaches to the hip.     

骨密度降低是女性患者全髋关节置换术后非骨水泥髋臼杯移位的高危因素

目的:探讨骨密度降低在女性患者中对非骨水泥臼杯位移的影响。方法:收集2013年10月至2015年11月遵义医学院第三附属医院骨科一病区收治的34例全髋关节置换术患者,均为女性,均为髋关节骨性关节炎。基于术前双能X线骨密度仪测量(DXA)的最低值,将患者分为骨密度正常组或低骨密度组(-3.5≤T≤-1)。骨密度组正常10例,年龄55~64岁;低骨密度组24例,年龄58~72岁。两组患者行全髋关节置换术时均植入非骨水泥陶瓷对陶瓷髋关节假体(Depuy美国),内衬系统均为Pinnacle杯。术中髋臼杯保持外展角45°、前倾角15°,基于立体影像测量分析(RSA)追踪术后3、6、12和24个月髋臼杯位移情况。结果:低骨密度组与正常骨密度组在臼杯位移的RSA测量差异有统计学意义。低骨密度组较正常骨密度组在术后前3个月内,臼杯的迁移差异有统计学意义。位移主要发生在X轴(95%置信区间0.01~0.31,P=0.006)和Y轴(95%置信区间0.20~0.39,P=0.003)。最初的旋转发生在单独的Z轴(95%置信区间-0.26~0.81,P=0.006)。结论:女性患者在全髋关节置换术后3个月,骨密度降低增加了非骨水泥杯的位移。     

Prognosis of dislocation after total hip arthroplasty

One hundred sixty-one dislocations after cemented total hip arthroplasty, with a mean follow-up period of 8 years after dislocation, were reviewed with the aim of establishing the prognosis. There were 84% single and 16% recurrent dislocations. Closed reduction was successful in 81% of cases. Thirty-seven percent of dislocations were early (within 5 weeks), 36% occurred in patients who had had previous surgery, and in 47% there was nonunion of the trochanter. There was a two-way interaction between these factors, and all factors were significant for recurrent dislocation. Twenty-six (16%) recurrent dislocations required surgery. The most common causes of recurrent dislocation demonstrated at operation were component malposition (58%) and failure of the abductor mechanism (42%). In total, 96% of cases were successfully treated.     

Cup size and risk of dislocation after primary total hip arthroplasty

We evaluated the relationship between cup diameter and dislocation risk in patients undergoing primary total hip arthroplasty (THA) with a 28-mm head. There were 50 dislocations, 28 of which occurred in 2221 (1.3%) THAs with a cup diameter smaller than 56 mm and 22 in 513 (4.3%) with a cup diameter of 56 mm or larger. Dislocation risk varied between 0.6% and 2.4% in the smaller cup group and between 4.1% and 5.2% in the larger cup group. The risk was substantially higher in the large cup group (unadjusted odds ratio, 3.5; 95% confidence interval, 2.0-6.2). Multivariable logistic regression revealed an adjusted odds ratio of 2.4 (95% confidence interval, 1.2-4.9). Patients with THA (28-mm head) had more than twice the risk of dislocation with cup size of 56 mm or higher compared to patients with smaller cups.     

Study of hip joint dislocation after total hip arthroplasty

The present study was undertaken to identify the factors responsible for hip joint dislocation after total hip arthroplasty, laying emphasis on analysis of the background variables of the patients. Of the 317 hips included in the study, ten (3.2%) dislocated. Only the anteversion angle of the cup differed significantly between the dislocation group and the dislocation-free group. The safe zone of the anteversion angle seems to be between 20 and 30 degrees. but it is also essential to set the antetorsion angle of the stem to match the shape of individual bones to create a more stable hip joint. This safe zone may be expanded by the additive effect of antetorsion angle of the stem.     

Trochanteric advancement for recurrent dislocation after total hip arthroplasty

Twenty-one patients had trochanteric advancement after experiencing an average of 3.9 dislocations in a mean period of 46 weeks following total hip arthroplasty. Before trochanteric advancement was performed, component malposition and mechanical impingement were excluded as causes of dislocation. Radiographic measurements revealed that the trochanter was advanced an average of 16 +/- 7.7 mm (1 SD). Four patients, all with rheumatoid arthritis, had trochanteric migration greater than 1 cm. Seventeen of the 21 hips had no further dislocations following trochanteric advancement, with mean follow-up period of 2.7 years. Two patients dislocated because of extremes in hip position and had no further dislocations. Two patients dislocated who had trochanteric migration greater than 1 cm. Only one patients with a technically satisfactory trochanteric advancement continued to dislocate repeatedly. In patients without component malposition or obvious sources of impingement, trochanteric advancement is an effective and safe procedure for prevention of recurrent dislocations after total hip arthroplasty.     

The incidence of implant fractures after total hip arthroplasty

Purpose

Implant fractures after total hip arthroplasty (THA) are considered as rare in clinical practice. Nevertheless they are relevant complications for patients, physicians, and the public health system leading to high socioeconomic burdens. The aim of this study was to assess the incidence of fractures after THAs in a comparative analysis of clinical studies and worldwide arthroplasty register datasets.

Methods

We calculated the pooled incidence of revision operations after fractures of THAs in a comparison of clinical studies published in Medline-listed journals and annual reports of worldwide arthroplasty registers in a structured literature analysis based on a standardised methodology.

Results

Included clinical studies (sample-based datasets) were mono-centre trials comprising a cumulative number of approximately 70,000 primary implantations whereas worldwide national arthroplasty register datasets referred to 733,000 primary implantations, i.e. approximately ten times as many as sample-based datasets. In general, sample-based datasets presented higher revision rates than register datasets with a maximum deviation of a 14.5 ratio for ceramic heads, respectively. The incidence of implant fractures in total hip arthroplasty in pooled worldwide arthroplasty register datasets is 304 fractures per 100,000 implants. In other words, one out of 323 patients has to undergo revision surgery due to an implant fracture after THA in their lifetime.

Conclusions

Implant fractures in total hip arthroplasty occur in a relevant number of patients. The authors believe that comprehensive arthroplasty register datasets allow more general evaluations and conclusions on that topic in contrast to clinical studies.     

Dual mobility cups in total hip arthroplasty

Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in orthopaedics. With the increase in the number of THAs performed in the world in the next decades, reducing or preventing medical and mechanical complications such as post-operative THA instability will be of paramount importance, particularly in an emerging health care environment based on quality control and patient outcome. Dual mobility acetabular component (also known as unconstrained tripolar implant) was introduced in France at the end of the 1970s as an alternative to standard sockets, to reduce the risk of THA dislocation in patients undergoing primary THA in France. Dual mobility cups have recently gained wider attention in the United States as an alternative option in the prevention and treatment of instability in both primary and revision THA and offer the benefit of increased stability without compromising clinical outcomes and implant longevity. In this article, we review the use of dual mobility cup in total hip arthroplasty in terms of its history, biomechanics, outcomes and complications based on more than 20 years of medical literature.     

全髋关节置换术后早期脱位研究进展

髋关节脱位是全髋关节置换(THA)后仅次于假体松动的主要并发症之一,多发生于术后早期(3个月内).尽管其发生已大大减少,但仍是影响THA疗效的早期并发症之一,对患者的精神和身体打击很大,如何防治一直是关注的焦点.该文就近年来THA后早期脱位研究进展作一综述.     

Metal-backed acetabular cups in total hip arthroplasty

Metal backing for the acetabular component of a total hip replacement, initially designed to allow replacement of the polyethylene liner, has since been universally accepted as a means of decreasing peak stresses at the interfaces of bone and cement. We studied the results of 238 total hip replacements that had been performed between 1980 and 1983 and that differed only in that 138 of the acetabular components had a metal backing and 100 were made of polyethylene only. Kaplan-Meier survival analysis, with three different modes of failure (radiolucency, loosening, and revision), showed a significant increase in the rate of failure of the metal-backed acetabular cup compared with the all-polyethylene cup: radiolucency, 39 compared with 23 per cent (p less than 0.0001); loosening, 4 compared with 2 per cent (p less than 0.0001); and revision, 6 compared with 2 per cent (p less than 0.0034). It was concluded that metal backing cannot be recommended for a cemented acetabular component of a total hip-replacement system.     

Locked inferior fracture dislocation after total hip arthroplasty

Acetabular fracture in conjunction with dislocation after total hip arthroplasty is a rarely reported event. We describe such a case with a unique fracture dislocation pattern, whereby the prosthetic femoral component dislocated inferiorly, fracturing the pelvis, and was locked in this position. The patient was treated with closed reduction under anesthesia and the fracture healed without further surgical intervention. However, she has experienced subsequent instability episodes and we have recommended revision surgery.     

Periprosthetic femoral fractures after total hip arthroplasty

BACKGROUND: The management of periprosthetic fracture following a total hip arthroplasty is difficult, requiring expertise in both trauma and revision surgery. With rising numbers of patients in the population living with hip prostheses in situ, the frequency of these fractures is increasing, and controversy remains over their ideal management. The objective of this study was to review all periprosthetic fractures at a single institution to identify injury and treatment patterns and their associated clinical outcomes. METHODS: Fifty-four periprosthetic fractures in 50 patients were reviewed to determine the relative frequency of fracture types, their complication rates and the clinical outcomes. Patient data were obtained through review of the clinical notes and individual patient follow up. Clinical outcomes were evaluated using the Oxford Hip Score and Harris Hip Score. RESULTS: The 54 fractures were classified using the Vancouver system, most of which were type B1 (20) or type B2 (10). The mean time to union for all fracture types was 4.6 months. A high non-union rate was seen among fractures fixed operatively. Fifteen per cent of fractures went on to develop loosening following treatment, suggesting an underrecognition at the time of injury. The average Harris Hip Score was 73.1 and Oxford Hip Score 30.3 for all fracture types at a mean follow up of 3.3 years. In the 15 patients treated with revision surgery, the most common complication was dislocation (27%). CONCLUSION: Treatment of patients with periprosthetic fractures requires recognition of the challenging nature of these injuries, the associated poor prognosis and the high complication rate.     

改良EPSTR预防全髋置换术后脱位

目的：探讨改良EPSTR法预防全髋置换术后脱位的临床疗效。方法：2006年1月至2007年5月,在85例（87髋）全髋置换中采用改良EPSTR法对后路结构进行修补,男39例,女46例;年龄62～85岁,平均69.5岁。新鲜股骨颈骨折58髋,股骨头坏死25髋,髋关节骨关节炎3髋,股骨粗隆间骨折内固定失败1髋。结果：85例均获随访,时间8～24个月,平均15个月,没有发现髋关节后脱位、髋关节外旋挛缩畸形和大转子骨折,术后6个月Harris评分平均为（89.2±4.5）分。结论：改良EPSTR法是一种预防全髋置换术后脱位的有效和简捷的方法,具有临床应用价值。     

Reduced risk of reoperation after treatment of femoral neck fractures with total hip arthroplasty

Background and purpose — Femoral neck fractures (FNFs) are commonly treated with some kind of arthroplasty, but evidence on whether to use hemiarthroplasty (HA) or total hip arthroplasty (THA) is lacking. HA reduces the risk of dislocation, but may lead to acetabular erosion. THA implies longer surgery and increased bleeding. THA may result in better function and health-related quality of life, but evidence is contradictory. We compared HA and THA and in terms of revision, reoperation and death.

Patients and methods — Data were extracted from the Swedish Hip Arthroplasty Register for 11,253 patients with acute FNF receiving cemented HA or THA during 2008–2012. 2,902 patients with THA were matched by propensity score matching with as many patients with HA based on age, sex, BMI, and ASA classification. We used competing risks survival regression with reoperation or death and revision or death as endpoints.

Results — THA patients had significantly reduced risk of revision (absolute risk reduction 0.51; 95% CI 0.39–0.67) and reoperation (0.58; 0.46–0.74). THA was associated with an almost 50% reduced mortality (risk ratio as competing risk for reoperation 0.51; 0.46–0.57).

Interpretation — In our national register study of femoral neck fractures, THA had a lower risk than HA for further surgical procedures related to the hip. The reasons for lower mortality after THA are not known. Despite matching, there might be a selection of more healthy patients for this procedure, and other factors unknown to us, with or without relation to the choice of implant.     

全髋关节置换术后脱位的原因分析及处理

[目的]探讨全髋关节置换术后发生脱位的原因、处理及预防方法.[方法]自1996～2004年在本院行全髋关节置换患者共850例,发生置换术后脱位7例,其中男4例,女3例;平均年龄67岁;通过对术前病史、手术入路、术后脱位的时间以及发生脱位的方向进行回顾性研究以探讨脱位的原因、处理以及如何预防.[结果]本组发生全髋关节置换术后脱位7例,其中5例(5/7)为初次全髋关节置换术后脱位,2例(2/7)为翻修手术后脱位;4例(4/7)有既往髋部手术史;1例有脑部手术后精神异常,不配合治疗;脱位方向均为前脱位;所有患者均采用正外侧入路即改良Hardinge入路.髋臼假体外展角2例(2/7)大于55°.发生脱位时间自术后当天至术后27个月,其中5例发生于术后3个月以内.所有7例患者在脱位后均首先给以麻醉下闭合复位、下肢皮牵引6周治疗,其中6例患者获得稳定并未再复发性脱位;1例患者在复位后3个月内又连续2次脱位,并在复位过程中发生髋臼松动,给以手术翻修髋臼调整外展角后获得稳定.[结论]导致全髋关节置换术后脱位的危险因素主要包括髋部手术史、术后患者不能严格按照医嘱进行康复训练、手术人路以及假体位置不良等.对于大多数脱位患者而言,闭合复位以及皮牵引6周是有效的治疗方法,对于复发性脱位的患者在分析脱位原因后可通过翻修手术获得髋关节的稳定.