Midterm Outcomes After Reconstruction of Superolateral Acetabular Defects Using Flying Buttress Porous Tantalum Augments During Revision Total Hip Arthroplasty

BackgroundPorous tantalum augments are versatile tools in reconstructing complex acetabular defects during revision total hip arthroplasty (THA). This study examines the clinical and radiographic outcomes of porous tantalum augments placed in the type I (flying buttress) configuration at two to 17-year follow-up in the largest cohort to-date in the literature.MethodsWe retrospectively analyzed 59 consecutive revision THAs involving the use of flying buttress augments between 2003 and 2018. The mean patient age and follow-up duration were 63.9 ± 11.6 years (range, 35-87) and 8 years (range, 2-17), respectively. The Oxford hip score was used to assess clinical outcome. The modified Moore classification was used to assess acetabular augment and shell osseointegration. Kaplan-Meier survival analysis with 95% confidence interval (CI) was used to assess implant survivorship.ResultsThe mean Oxford hip score improved from 15.9 ± 6.2 preoperatively to 35.0 ± 6.5 at a mean follow-up of eight years (P < .0001). Radiographic assessment using the modified Moore classification demonstrated five signs of osseointegration in 49 hips (83.1%), four signs in six hips (10.2%), three signs in one hip (1.7%), and one sign in one hip (1.7%). Kaplan-Meier analysis demonstrated ten-year survivorship of 88.9% (95% CI 74.4-95.4) with all-cause revision as end point and 94.3% (95% CI 83.1-98.2) with revision for acetabular aseptic loosening as end point.ConclusionTreatment of superolateral acetabular defects during revision THA using porous tantalum augments placed in the type I (flying buttress) configuration provides excellent implant survivorship and favorable clinical outcomes at mid-term follow-up.Level of EvidenceTherapeutic Level IV.     

Acetabular reconstruction in revision total hip arthroplasty

The number of total hip arthroplasty (THA) procedures performed annually continues to rise. Specific challenges, including acetabular bone loss, are commonly encountered at the time of revision surgery, and orthopaedic surgeons must be prepared to address them. This review focuses on topics related to acetabular reconstruction, including pre-operative patient evaluation (clinical and radiographic), pre-operative planning, common causes of acetabular failure, classification of acetabular bone loss, methods of acetabular reconstruction, and clinical results based on reconstruction method. Pre-operative patient evaluation for revision THA begins with a thorough history and physical examination as well as laboratory workup to rule out infection. Detailed radiographic evaluation and pre-operative planning are also essential and will facilitate communication amongst all members of the operative team. Although there are several ways to describe acetabular bone loss, the Paprosky classification system – defined by anterosuperior and posteroinferior acetabular column integrity – is the system most commonly used today and will guide treatment strategy. Several treatment strategies have been developed and may be termed either “cemented” (e.g. impaction grafting, ring and cage construction, structural allograft) or “uncemented” (e.g. hemispheric shell ± porous metal augment, cup-cage, custom triflange acetabular component). Although each strategy has its advantages and disadvantages, the general principles remain the same. Successful treatment depends upon detailed pre-operative assessment, planning, and team-based plan execution. Uncemented techniques that allow for biologic fixation are preferred. In the special case of pelvic discontinuity, acetabular distraction is the authors’ preferred technique. Longer term studies are still needed to evaluate the longevity of each of the various reconstruction methods presented.     

Revision for Aseptic Loosening of Highly Porous Acetabular Components in Primary Total Hip Arthroplasty: An Analysis of 20,993 Total Hip Replacements

BackgroundHighly porous-coated titanium acetabular components have a high coefficient of friction and ultraporous surfaces to enhance bone ingrowth and osseointegration in total hip arthroplasty (THA). There have been concerns with the development of early radiolucent lines and aseptic loosening of highly porous acetabular components. It is unclear whether these concerns relate to a specific implant or the entire class. The aim of this study is to compare the revision rates for aseptic loosening of highly porous acetabular combinations in primary THA using data from a large joint replacement registry.MethodsData were retrieved from the Australian Orthopedic Association National Joint Replacement Registry for the study period September 1999 to December 2019. All primary THA procedures recorded and performed for osteoarthritis using the most common combinations for each highly porous acetabular component with highly cross-linked polyethylene and a 32-mm or 36-mm femoral head were included. The primary outcome measure was revision for aseptic loosening of the acetabular component. Results were adjusted for patient age and gender.ResultsThere were 20,993 primary THA procedures performed for osteoarthritis using a highly porous acetabular component across 6 combinations. Relative to the POLARSTEM/R3 (StikTite), the Exeter V40/Tritanium had a significantly higher risk of revision for aseptic loosening of the acetabular component (hazard ratio 0.21, 95% confidence interval 0.06-0.74, P = .014). There was no difference between any other highly porous acetabular component combination and no late revisions for aseptic loosening.ConclusionHighly porous-coated titanium acetabular components have low rates of aseptic loosening with long-term follow-up. A difference between components may exist.Level of EvidenceLevel III.     

Total hip arthroplasty in acetabular fractures

Total Hip Arthroplasty (THA) is a well-accepted treatment for established hip arthritis following acetabular fractures. If a conservatively managed or operated case progresses to non-union/mal-union failing to restore the joint integrity, it may eventually develop secondary arthritis warranting a total hip arthroplasty. Also, in recent years, acute total hip arthroplasty is gaining importance in conditions where the fracture presents with pre-existing hip arthritis, is not amenable to salvage by open reduction and internal fixation, or, a poor prognosis is anticipated following fixation.There are several surgical challenges in performing total hip arthroplasty for acetabular fractures whether acute or delayed. As a separate entity elderly patients pose a distinct challenge due to osteoporosis and need stable fixation for early weight bearing alleviating the risk of any thromboembolic event, pulmonary complications and decubitus ulcer. The aim of surgery is to restore the columns for acetabular component implantation rather than anatomic fixation. Meticulous preoperative planning with radiographs and Computed Tomography (CT) scans, adequate exposure to delineate the fracture pattern, and, availability of an array of all instruments and possible implants as backup are the key points for success. Previous implants if any should be removed only if they are in the way of cup implantation or infected. Press fit uncemented modern porous metal acetabular component with multiple screw options is the preferred implant for majority of cases. However, complex fractures may require major reconstruction with revision THA implants especially when a pelvic discontinuity is present.     

Total hip arthroplasty in acetabular fractures

Total Hip Arthroplasty (THA) is a well-accepted treatment for established hip arthritis following acetabular fractures. If a conservatively managed or operated case progresses to non-union/mal-union failing to restore the joint integrity, it may eventually develop secondary arthritis warranting a total hip arthroplasty. Also, in recent years, acute total hip arthroplasty is gaining importance in conditions where the fracture presents with pre-existing hip arthritis, is not amenable to salvage by open reduction and internal fixation, or, a poor prognosis is anticipated following fixation.There are several surgical challenges in performing total hip arthroplasty for acetabular fractures whether acute or delayed. As a separate entity elderly patients pose a distinct challenge due to osteoporosis and need stable fixation for early weight bearing alleviating the risk of any thromboembolic event, pulmonary complications and decubitus ulcer. The aim of surgery is to restore the columns for acetabular component implantation rather than anatomic fixation. Meticulous preoperative planning with radiographs and Computed Tomography (CT) scans, adequate exposure to delineate the fracture pattern, and, availability of an array of all instruments and possible implants as backup are the key points for success. Previous implants if any should be removed only if they are in the way of cup implantation or infected. Press fit uncemented modern porous metal acetabular component with multiple screw options is the preferred implant for majority of cases. However, complex fractures may require major reconstruction with revision THA implants especially when a pelvic discontinuity is present.     

The value of computed tomography based navigation in revision total hip arthroplasty

Purpose

This study investigates the accuracy of a computed tomography (CT)-based navigation system for accurate acetabular component placement during revision total hip arthroplasty (THA).

Methods

We performed a retrospective review of 30 hips in 26 patients who underwent cementless revision THA using a CT-based navigation system; the control group consisted of 25 hips in 25 patients who underwent cementless primary THA using the same system. We analysed the deviation of anteversion and inclination angles among the pre-operative plan, intra-operative records from the navigation system and data from postoperative CT scans.

Results

There were no significant differences between groups (P < 0.05) in terms of mean deviation between pre-operative planning and postoperative measurements or between intraoperative records and postoperative measurements.

Conclusion

CT-based navigation in revision THA is a useful tool that enables the surgeon to implant the acetabular component at the precise angle determined in pre-operative planning.     

Evaluation of a porous tantalum uncemented acetabular cup in revision total hip arthroplasty: clinical and radiological results of 60 hips

Long-term survival of the acetabular component in revision total hip arthroplasty (THA) is determined by initial implant stability and bone ingrowth. Highly porous Trabecular Metal (TM, Zimmer, Inc, Warsaw, Ind) facilitates ingrowth and may be an ideal material for revision THA. The outcome and survivorship of a TM, nonmodular, uncemented acetabular cup were assessed in 60 consecutive patients undergoing revision THA (mean follow-up, 42 months; range, 14-68 months). Most (55/60) acetabular cups were implanted without screw fixation. Mean Harris Hips Scores improved from 74.8 preoperatively to 94.4 at last follow-up. Serial radiographs demonstrated excellent bone apposition and bone graft incorporation. Complications were limited to 7 cases of dislocation and 1 revision for aseptic loosening. The TM acetabular cup appears suitable for use in revision THA and warrants further study.     

Anatomic placement of the acetabular implant in cementless total hip arthroplasty does not adversely affect the implant survival and patient satisfaction

ObjectiveThis study aimed to evaluate if the acetabulum's conservative reaming with preservation of the medial acetabular bone and anatomic placement of the acetabular implant in cementless total hip arthroplasty (THA) has any adverse effect on the radiological outcome, long term implant survival and patient satisfaction.Methods106 consecutive patients were identified from a single surgeon practice who underwent cementless THA from 2005 to 2010. Twenty-one were lost to follow up, and five patients died unrelated to THA. Eighty patients were available for the study. The mean follow-up was 8.6 years (range 5.7–11.6). The mean age was 61.9 years. Immediate pre- and postoperative radiographs were reviewed to calculate combined offset (Acetabular offset – AO, plus Femoral offset – FO). Implant failure, aseptic loosening, revision surgery, patient satisfaction and complications were assessed on long-term follow-up.ResultsAcetabular component survival was 100% with no aseptic failure. None of the patients had revision surgery for any cause. The mean difference in the acetabular offset and combined offset postoperatively was within 3 mm. One patient had a dislocation, and one had a prosthetic joint infection (PJI). 95% of the patients in this series would recommend the hip replacement procedure to others, with a mean satisfaction score of 8.7 (range; 1–10).ConclusionConservative acetabular reaming with preservation of medial acetabulum bone with the anatomic placement of the acetabular implant in cementless THA is safe with no adverse effects on implant survival and patient satisfaction. It offers the advantage of preserving the patient's bone stock, which would potentially be of significant advantage to the patient and the surgeon in case of revision arthroplasty.     

Highly Porous Titanium Acetabular Components in Primary and Revision Total Hip Arthroplasty: A Systematic Review

BackgroundA number of papers have been published reporting on the clinical performance of highly porous coated titanium acetabular cups in primary and revision total hip arthroplasty (THA). However, no systematic review of the literature has been published to date.MethodsThe US National Library of Medicine (PubMed/MEDLINE), Embase, and the Cochrane Database of Systematic Reviews were queried for publications utilizing the following keywords: “tritanium” OR “highly-porous” AND “titanium” OR “acetabular” AND “trabecular” AND “titanium”.ResultsOverall, 16 studies were included in this review (11,366 cases; 60% females, 2-7 years mean follow-up). The overall survival rate of highly porous titanium acetabular components in primary cases was 99.3% (10,811 of 10,886 cases), whereas the rate of aseptic loosening was 0.1%. The overall survival rate of the highly porous titanium acetabular components in revision THA cases was 93.5% (449 of 480 cases), whereas the rate of aseptic loosening was 2.1%.ConclusionThere was moderate quality evidence to show that the use of highly porous titanium acetabular components in primary and revision THA cases is associated with satisfactory clinical outcomes in the short- and medium-term, without showing any evidence of cup migration or radiolucency. Taking into consideration that there is no evidence yet regarding the long-term survivorship of these components, we feel that further research of higher quality is required to generate more evidence-based conclusions regarding the longevity of highly porous titanium acetabular implants compared with conventional titanium counterparts.     

人工全髋关节置换术后髋臼假体初始不稳定原因分析及处理

目的探讨初次人工全髋关节置换术后髋臼假体初始不稳定的原因及处理方法。方法回顾性分析2003年1月-2010年6月初次人工全髋关节置换术后出现髋臼假体初始不稳定行髋臼翻修术的19例患者临床资料。男11例,女8例;年龄55～79岁,平均67.2岁。左髋9例,右髋10例。应用骨水泥型髋臼假体7例,非骨水泥型12例。初次置换术后3周～6个月行翻修术,平均4.5个月。分析髋臼假体初始不稳定的原因,比较翻修术前后髋臼假体骨覆盖率及髋关节功能Harris评分。结果髋臼假体初始不稳定与髋臼的处理、假体的选择及放置角度、骨水泥操作技术不当等有关。翻修术后l例出现坐骨神经麻痹,7周后自行恢复;1例髋臼前壁轻微骨折,3个月后骨折愈合。术后切口均Ⅰ期愈合,无关节假体周围感染、血管损伤、假体脱位、下肢深静脉血栓形成等并发症发生。术后患者均获随访,随访时间11～73个月,平均28个月。患者均未出现髋臼假体初始不稳定。髋臼假体骨覆盖率由初次置换时的67.9%±5.5%提高至翻修术后87.7%±5.2%,差异有统计学意义(t=11.592,P=0.003)。末次随访时Harris评分为(84.4±4.6)分,较术前的(56.5±9.3)分显著提高(t=11.380,P=0.005)。结论术前详细计划、选择合适的假体、妥善处理髋臼、按合理角度植入髋臼假体有助于获取良好的髋臼假体初始稳定性。     

Cementless jumbo cups for revision of failed Furlong prosthesis. A case series

BackgroundRevision of failed total hip arthroplasty (THA) presents great challenge to any orthopaedic surgeon especially in the presence of acetabular defects where the main goal is to achieve durable fixation of prosthetic components to bone which is the key to successful revision surgery.MethodsSeventeen patients (17 hips) with mean age of 52 (40–61) years had revision surgery for aseptic failure of Furlong hydroxyapatite-ceramic-coated (HAC) prosthesis using cementless jumbo cups. Patients were reviewed clinically and radiographically with mean follow-up of 3.5 years (2–6). No patient was lost to follow up.ResultsAll revised acetabular components showed polyethylene wear, severe metallosis, with acetabular defects IIB (4/17), and IIIA (13/17) according to Paprosky classification. The femoral component was well fixed in all cases but one patient had stem revision for femoral fracture mal-union. There was one early post-operative infection; there was no postoperative dislocation, sciatic nerve injury, periprosthetic fracture or deep venous thrombosis. At last follow-up, no progressive radiolucencies or acetabular migration was identified. The mean Harris hip score improved from 42 (24–59) pre-operatively to 85 (72–92).ConclusionGood clinical results and radiographic stability were obtained at short term follow up after acetabular revision using cementless jumbo cups, which justify its use in revision surgery even in the face of major acetabular defects. Furlong HAC femoral component gives excellent long-term survival in young and active patients with a survival rate of 94% at 18.6 years.     

颗粒松质骨压紧植骨全髋关节置换术治疗创伤性髋关节炎的疗效

目的探讨颗粒松质骨压紧植骨全髋关节置换术(THA)治疗髋臼骨折继发创伤性髋关节炎的疗效。方法1998年12月-2005年5月,对15例髋臼骨折继发创伤性髋关节炎患者行颗粒松质骨压紧植骨THA,所有患者髋臼假体均采用骨水泥固定,颗粒骨均取自体骨,术后24h后开始被动活动,3个月后开始全负重锻炼。临床随访采用Harris髋关节评分(HSS)系统评分,对任何原因引起髋臼假体翻修均视为临床失败。根据Conn等影像学评价法观察颗粒骨长人情况,根据DeLee的三区法测量臼杯、骨水泥与移植骨间的界面宽度,臼杯的移位程度则依据其相对于泪点间线的距离而定。结果14例患者获得平均4．3年(1．0-7．5年)随访,HHS评分由术前平均42分(10-62分)提高到随访结束时平均84分(58-98分)。1例髋部有轻度疼痛,无患者行翻修手术。大部分髋部恢复了其正常的旋转中心,仅有2例高出对侧0．8 mm。大多数患者影像学表现稳定,2例在Ⅰ区和Ⅲ区出现进行性增宽的透亮带,1例在Ⅲ区出现非进行性增宽的透亮带。1例臼杯假体在术后7年出现明显移位(6 mm),但并没有行翻修手术。结论颗粒骨压紧植骨技术作为一种生物学髋臼重建方法,其联合THA治疗髋臼骨折后继发创伤性关节炎伴髋臼缺损的疗效令人满意,能够恢复髋关节的正常解剖和功能活动。     

THA翻修术中髋臼骨缺损的处理策略

目的探讨全髋关节置换术（THA）翻修术中髋臼骨缺损重建的方法及疗效。方法回顾1999年6月至2007年5月,在THA翻修术中处理的髋臼骨缺损112例（117髋）。根据Saleh KJ的改良分型法,Ⅰ型缺损14髋、Ⅱ型缺损26髋、Ⅲ型缺损47髋、Ⅵ型缺损16髋、Ⅴ型缺损14髋。分别采用大直径非骨水泥假体臼、非骨水泥假体臼＋松质颗粒植骨、骨水泥假体臼＋Cage＋松质颗粒植骨和骨水泥假体臼＋定制型假体＋松质颗粒植骨,对不同类型骨缺损进行修复。术后定期随访,采用Harris方法评估髋关节功能,根据X线片判断假体是否有松动,移植骨是否愈合。结果随访时间平均45（13～118）个月。除4髋因脱位或假体周围骨折进行再翻修外,其余效果良好。术后Harris评分平均86.2分,较术前平均改善40.6分。X线片无假体松动下沉,可见移植骨-宿主骨交界处有连续性小梁骨通过。结论在THA翻修术中,大部分髋臼骨缺损可使用较大型号非骨水泥假体或加松质颗粒植骨进行修复;对于影响假体稳定性的较大缺损,使用骨水泥假体臼＋Cage＋松质颗粒植骨的方法可获得良好效果;定制型假体在处理严重髋臼骨缺损中有具独特优势,有良好的临床应用前景。     

Acetabular cup positioning in revision total hip arthroplasty with Paprosky type III acetabular defects: Martell radiographic analysis

Purpose

This study evaluates acetabular cup position in the setting of revision total hip arthroplasty (THA) with severe acetabular bone defects.

Methods

With a definition of safe zone of abduction (30–50°) and anteversion (5–25°), acetabular cup position was measured by a digital image analysis program for 34 patients with Paprosky type III acetabular bone defects.

Results

There were 24 cups (71 %) for abduction and 26 cups (76 %) for anteversion located in the safe zone. Nineteen cups (56 %) were within the safe zone for both abduction and anteversion. There was no dislocation, however one cup out of the safe zone resulted in early cup failure due to aseptic loosening.

Conclusions

The acetabular cup positioning in patients with Paprosky type III defects was 'optimal' in half of the cases. The prevalence of optimal acetabular cup position was similar to those reported in primary THA, suggesting that the presence of a large acetabular bone defect may not be a significant risk factor for suboptimal acetabular cup positioning in the setting of revision THA.     

Clinical and Radiological Outcome of Acetabular Reconstruction Rings in Complex Primary and Revision Total Hip Arthroplasty

BackgroundAcetabular reconstruction in complex primary and revision total hip arthroplasty (THA) with bone loss poses a great challenge. We aim to evaluate the medium-term clinical and radiological outcome of reconstruction rings used in these difficult situations. MethodsWe retrospectively reviewed a consecutive series of acetabular reconstructions with Muller ring or Bursh-Schneider cage from January 2009 to December 2016. The reconstruction rings were used in 66 hips (65 patients). There were 41 complex primary THA and 25 revision THA. The mean follow-up period was 76 months (range, 37–167 months). Clinical evaluation includes the assessment of Harris hip score, visual analogue scale (VAS) score, limb length discrepancy, and activities of daily living. The radiographs were analyzed for any signs of loosening, osteolysis, acetabular migration, and heterotopic ossification.ResultsThe overall survival rate was 95% for revision in aseptic loosening and 87% for any reason at an average follow-up of 6.3 years. Twelve patients died and 9 patients were lost to follow-up leaving 45 patients for final functional analysis. Among the 45 patients, excellent to good results were seen in 33 patients, fair results were seen in 5 patients, poor results were seen in seven patients. Two patients had aseptic loosening and another two patients developed deep chronic infection awaiting two-stage revision.ConclusionReconstruction rings still place a role in the armamentarium for complex acetabular reconstruction. It helps to reliably restore the bone stock, have an acceptable survival rate and satisfactory functional outcome at medium to long-term follow-up.     

Does the Risk of Rerevision Vary Between Porous Tantalum Cups and Other Cementless Designs After Revision Hip Arthroplasty?

Clinical Orthopaedics and Related Research® - Earlier results with porous tantalum acetabular cups in revision THA generally have been favorable. Recently there has been some evidence...     

3D Printed Acetabular Components for Complex Revision Arthroplasty

Recent studies have shown high early failure rates with Cup Cage constructs in complex revision surgery for Paprosky 3B acetabular defects. As a result, the use of 3D printed custom-made acetabular components has become more common. In this case series, we present two cases that demonstrate the latest advancement in 3D printed implants for severe acetabular bone loss. The follow up was 3 and 7 years. Neither patient has undergone revision surgery of the acetabular component to date. One patient sustained a femoral peri-prosthetic fracture requiring plate fixation. This case study demonstrates that 3D printed implants have excellent intraoperative and immediate postoperative outcomes in revision surgery for severe acetabular bone defects.     

髋臼加强环联合同种异体骨植骨重建髋臼在髋关节翻修中的应用

目的总结髋臼加强环(Cage)联合同种异体骨植骨重建髋臼在髋关节翻修术中的应用及疗效。方法 2006年2月-2010年8月,对14例(14髋)行人工全髋关节翻修术的重度髋臼骨缺损患者采用Cage联合同种异体骨植骨重建髋臼。男6例,女8例;年龄45～76岁,平均59.2岁。初次置换至此次翻修术时间为5～12年,平均7.2年。翻修原因:感染8例,骨溶解及假体松动6例。术前髋关节功能Harris评分为(37.7±5.3)分。髋臼骨缺损按照美国骨科医师协会(AAOS)分型标准:Ⅲ型8例,Ⅳ型6例。结果术后切口均Ⅰ期愈合,无坐骨神经损伤、下肢深静脉血栓形成等并发症发生。患者均获随访,随访时间14～62个月,平均44个月。患者疼痛症状均明显缓解或消失。末次随访时髋关节Harris评分为(89.7±3.2)分,与术前比较差异有统计学意义(t=—44.40,P=0.04)。X线片示髋臼假体均无松动,植骨未见明显吸收,并逐渐与宿主骨融合。结论在髋关节翻修时,采用Cage联合同种异体骨植骨能有效修复髋臼骨缺损并重建髋臼,近期疗效满意,远期疗效尚需进一步随访观察。     

The Harris-Galante cementless THA: a 19- to 25-year follow-up study

The goal of this study was to evaluate the long-term survivorship of primary cementless total hip arthroplasty (THA) using Harris-Galante porous I acetabular and Harris-Galante porous femoral components. From July 1985 to December 1991, we performed primary cementless THA on 76 hips (70 patients). Twenty-nine patients (31 hips) died due to causes unrelated to the THA, and 6 patients (7 hips) were lost to follow-up. Of 76 hips (70 patients) studied, 38 hips (35 patients) were available for follow-up at a mean 22.5 years (range, 19-25 years) postoperatively. Mean patient age at index procedure was 51.2 years (range, 42-65 years). Average Harris Hip Score was 40.5 points preoperatively and 85.8 points at final follow-up. No patient had an early or late postoperative deep infection. Radiographically, the acetabular component fixation was stable in all 38 hips. The femoral component was bone-ingrown in 26 hips, stable-fibrous in 10, and unstable in 2. One unstable hip required revision of the femoral component. Dissociation of the polyethylene liner occurred in 3 hips without fractures of the metal locking tines and required revision of the polyethylene liner and the articular head. A total of 4 hips had documented revision, and 1 femoral component failed radiographically. The survival rate with the endpoint defined as revision surgery and radiographic loosening was 86.8% at 22.5 years of follow-up. Mean polyethylene wear was 0.085 mm/year (range, 0.031-0.15 mm). This study found that the Harris-Galante porous I acetabular and Harris-Galante porous femoral components produce excellent long-term results.     

Acetabular reinforcement ring in primary total hip arthroplasty: a minimum 10-year follow-up

INTRODUCTION: We report the results of a titanium acetabular reinforcement ring with a hook (ARRH) in primary total hip arthroplasty (THA), which was introduced in 1987 and continues to be used routinely in our center. The favorable results of this device in arthroplasty for developmental dysplasia and difficult revisions motivated its use in primary THA. With this implant only minimal acetabular reaming is necessary, anatomic positioning is achieved by placing the hook around the teardrop and a homogenous base for cementing the polyethylene cup is provided. MATERIALS AND METHODS: Between April 1987 and December 1991, 241 THAs with insertion of an ARRH were performed in 178 unselected, consecutive patients (average age 58 years; range 30-84 years) with a secondary osteoarthrosis in 41% of the cases. RESULTS: At the time of the latest follow-up, 33 patients (39 hips) had died and 17 cases had been lost to follow-up. The median follow-up was 122 months with a minimum of 10 years. Eight hips had been revised, leaving 177 hips in 120 living patients without revision. Six cups were revised because of aseptic loosening. Two hips were revised for sepsis. The mean Merle d'Aubigné score for the remaining hips was 16 (range 7-18) at the latest follow-up. For aseptic loosening, the probability of survival of the cup was 0.97 (95% confidence interval, 0.94-0.99). However, analysis of radiographs implied loosening in seven other cups without clinical symptoms. CONCLUSIONS: The results of primary THA using an acetabular reinforcement ring parallel the excellent results of these implants often observed in difficult primary and revision arthroplasty at a minimum of 10 years. Survivorship is comparable to modern cementless implants. Medial migration that occurs with loosening of the acetabular component seems to be prevented with this implant. Radiographic loosening signs can exist without clinical symptoms.