The medium-term results of the Stanmore non-invasive extendible endoprosthesis in the treatment of paediatric bone tumours

In skeletally immature patients, resection of bone tumours and reconstruction of the lower limb often results in leg-length discrepancy. The Stanmore non-invasive extendible endoprosthesis, which uses electromagnetic induction, allows post-operative lengthening without anaesthesia. Between 2002 and 2009, 55 children with a mean age of 11.4 years (5?to 16) underwent reconstruction with this prosthesis; ten patients (18.2%) died of disseminated disease and one child underwent amputation due to infection. We reviewed 44 patients after a mean follow-up of 41.2 months (22 to 104). The mean Musculoskeletal Tumor Society score was 24.7 (8 to 30) and the Toronto Extremity Salvage score was 92.3% (55.2% to 99.0%). There was no local recurrence of tumour. Complications developed in 16 patients (29.1%) and ten (18.2%) underwent revision. The mean length gained per patient was 38.6?mm (3.5 to 161.5), requiring a mean of 11.3?extensions (1 to 40), and ten component exchanges were performed in nine patients (16.4%) after attaining the maximum lengthening capacity of the implant. There were 11?patients (20%) who were skeletally mature at follow-up, ten of whom had equal leg lengths and nine had a full range of movement of the hip and knee. This is the largest reported series using non-invasive extendible endoprostheses after excision of primary bone tumours in skeletally immature patients. The technique produces a good functional outcome, with prevention of limb-length discrepancy at skeletal maturity.     

骨肿瘤初次保肢手术后生物性重建失败的肿瘤假体翻修术

目的评估骨肿瘤初次保肢手术后生物性重建失败的肿瘤假体翻修的疗效。方法2004至2006年，13例骨肉瘤和3例骨巨细胞瘤患者在香港威尔斯亲王医院接受手术治疗。15例患者应用同种异体骨重建，另1例患者应用带血管腓骨移植重建骨缺损。应用肿瘤型假体进行翻修手术的重建。翻修术后患者膝关节活动范围良好时，订制的可延长假体接受延长手术。结果患者平均年龄23．2岁（13～43岁），平均随诊26．4个月（6～47个月）。翻修手术的原因包括：7例患者出现同种异体骨骨折或软骨下骨塌陷，5例患者骨不愈合，3例患者异体骨感染，1例患者膝关节僵硬。翻修手术的假体包括10例患者应用订制型假体，其他患者应用组合式假体。翻修手术的部位包括9例股骨远端假体，6例胫骨近端假体和1例股骨中段假体。订制假体中6例是可延长假体，假体的延长方式中5例是微创延长、1例无创延长。翻修手术后，膝关节活动改善，平均从18．1°（0°-90°）至91．9°（50°-120°）。下肢缩短不等长畸形从平均5cm（2-11．5cm）纠正至平均1．5cm（0-4cm）。翻修术后患肢功能MSTS评分从34．6％改善到89．2％。翻修术后2例患者出现部分皮肤坏死，1例患者出现腓总神经麻痹，以后部分恢复，1例患者出现胫骨裂纹骨折；没有感染和植入物失败。结论保肢手术后生物学重建失败所引起下肢缩短和僵硬，应用人工假体翻修是可行的，早期效果令人鼓舞。膝关节僵硬患者可获得良好的关节活动度。严重的下肢缩短畸形通过可伸长假体逐渐获得纠正。     

Extendible replacements of the proximal tibia for bone tumours

Limb salvage is now customary in the treatment of primary bone tumours. The proximal tibia is a frequent site for these neoplasms but reconstruction, especially in children, is a formidable challenge. We reviewed 20 children with extendible replacements of the proximal tibia, all with a minimum follow-up of five years. Five died from their disease and, of the remaining 15, four had above-knee amputations for complications. Infection occurred in seven patients; in five it was related to the lengthening procedure. Aseptic loosening is inevitable in the younger children and only two have avoided a revision, amputation or other major complication; both were aged 12 years at the time of the initial surgery. Despite this, 11 children are alive with a functioning leg and a mean Musculoskeletal Tumour Society functional score of 83%. The lengthening mechanisms used in our series required extensive open operations. We are now using a simpler, minimally invasive, technique which we hope will decrease the incidence of complications. At present, the use of extendible prostheses of the proximal tibia remains an experimental procedure.     

High complication rate after extendible endoprosthetic replacement of the proximal tibia: a retrospective study of 42 consecutive children

Background and purpose — The long-term outcome of reconstruction with extendible prostheses after resection of tumors the proximal tibia in children is unknown. We investigated the functional outcome, complication rate and final limb salvage rate after this procedure.

Patients and methods — 42 children who had a primary extendible replacement of the proximal tibia for bone tumor with a Stanmore implant between 1992 and 2013 were identified in the department’s database. All notes were reviewed to identify the oncological and functional outcomes, the incidence of complications and the rate of amputation. 20 children were alive at final follow-up. Median follow-up time was 6 years and minimum follow-up for surviving patients was 3 years.

Results — The overall limb salvage rate was 35/42; amputation was needed in 7 children. 15 implants were revised with a new implant. The Musculoskeletal Tumor Society Score was 73% (40–93) at final follow-up. The overall complication rate was 32/42. Soft tissue problems were the most common mode of complication, noted in 15 children, whereas structural failure and infection occurred in 12 children each. Use of prostheses with non-invasive lengthening was associated with a higher infection rate as compared with conventional ones (4/6 vs. 8/36) and inferior limb survival.

Interpretation — Extendible replacements of the proximal tibia allow for limb salvage and satisfactory late functional outcome but have a high rate of complications. The use of non-invasive lengthening implants has not shown any benefit compared with conventional designs and is, rather, associated with higher risk for infection and amputation.     

Non-invasive expandable prosthesis in musculoskeletal oncology paediatric patients for the distal and proximal femur. First results

Purpose

The non-invasive expandable prosthesis for skeletally immature patients is used after limb salvage surgery following tumor resection. The aim of the study was to assess the effectiveness of this treatment.

Methods

Seven paediatric patients with femoral tumors had resection and limb salvage with an uncemented non-invasive growing prosthesis. Mean age at the time of surgery was 9.8 (range 8–12) years. There were six distal femur osteosarcomas and one proximal femur Ewing sarcoma. Six total knee prosthesis were implanted at the time of primary tumor resection and one bipolar hip prosthesis was a revision from a failed osteoarticular hip allograft. Functional outcomes and emotional acceptance were assessed using the MSTS score.

Results

The mean follow-up was 65.3 months (range 29–91) months. Two patients died of pulmonary metastasis and there was no local recurrence. The mean femoral resection was 18 cm (range 17–19) on the knee, and 24 cm on the hip. Mean total expansion was 36.4 mm (range 12.3–63.5). The mean MSTS score after rehabilitation was 26.3 (range 21–29). There was one lengthening device failure, one late infection and one patient who required iliofemoral bypass grafting surgery for a pelvic metastasis. No local recurrence occurred.

Conclusions

The non-invasive expandable prosthesis reduces the final limb-length discrepancy in growing patients with an acceptable function and appears to have an advantage as compared to invasive expandable prostheses which require multiple surgical procedures, but the complications rate is still high.

     

Revision arthroplasty with use of a total femur prosthesis

BACKGROUND: Surgeons performing revision arthroplasties of the hip and knee are confronted with a growing number of patients with extensive loss of bone stock. Implantation of a total femur prosthesis is a possible method of treatment of such patients. The purpose of this study was to assess the functional outcomes and the complications associated with total femur replacements used in revision arthroplasty. METHODS: We evaluated the results associated with 100 total femur prostheses that had been implanted during revision arthroplasty in 100 consecutive patients without infection. The mean duration of follow-up was five years. The prosthesis was implanted because of a complication of a total hip replacement in seventy-seven patients, because of a complication of a total knee replacement in four, and because of a complication affecting the diaphysis of the femur in nineteen. Thirty-nine patients had sustained a periprosthetic fracture, usually in combination with loosening of the prosthesis, before the revision. The radiographs made at the time of the latest follow-up were evaluated for signs of loosening and material failure. The preoperative and postoperative function of the hip and knee was assessed according to the Enneking score. Five patients were lost to follow-up. RESULTS: Sixty-five patients (68%) had no complications. Deep infection was found in twelve patients (13%); dislocation, in six (6%); material failure, in three (3%); patellar problems, in two (2%); and peroneal nerve palsy, in one (1%). The mean preoperative Enneking score for hip function was 1.25 points, and it improved to 3.29 points postoperatively. The mean Enneking score for knee function was 2.09 points preoperatively and 3.29 points postoperatively. CONCLUSIONS: We believe that the total femur prosthesis is a useful implant for patients with extensive bone loss at revision arthroplasty. While the infection rate was high, the overall functional results for both the hip and the knee were rated as better than good with the Enneking classification.     

Management of septic complications following modular endoprosthetic reconstruction of the proximal femur

In a retrospective single-centre study 170 consecutive patients were included who received a Kotz modular prosthesis after resection of bone tumours of the proximal femur to evaluate the management of prosthetic infection. Infection occurred in 12 of 166 patients available for follow-up (six males; six females; mean age, 47 years; range, ten to 75 years) after a mean of 39 months (range, one to 166 months; infection rate, 7.2%). Mean follow-up was 54 months (range, four to 200 months). One patient died of septic shock. Two patients were treated by wound revision only. Treatment of infection in the remaining patients was one-stage revision in eight and hip disarticulation in one. Infection control by one-stage revision was achieved in five of eight patients; re-infection occurred in three patients and was successfully treated by further revision in all of them. The overall success rate for controlling infection was 83.3%.     

Cementless revision total hip arthroplasty without allograft in severe proximal femoral defects

This study evaluates the difficult reconstructive challenge of severe proximal femoral bone loss. We present intermediate-term results of 46 hips with extensive proximal femoral bone loss that underwent revision total hip arthroplasty using cementless distal fixation without supplemental allograft. All were evaluated with the Harris hip score at a minimum of 2 years. Radiographs were assessed using the Engh fixation scale. At a mean of 6.4 (range 2-12) years, 43 of the 46 prostheses were functioning well. Two patients required revision for symptomatic loosening, and 1 prosthesis remains radiographically loose with a fair clinical score. Mean Harris hip score was 77 at last follow-up. There were 6 intraoperative femur fractures, 9 dislocations, 10 cases of severe stress shielding, and no infections.     

The results of a proximally-coated cementless femoral component in total hip replacement: a five- to 12-year follow-up

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading.     

Segmental proximal femoral bone loss and revision total hip replacement in patients with developmental dysplasia of the hip: the role of allograft prosthesis composite

The treatment of substantial proximal femoral bone loss in young patients with developmental dysplasia of the hip (DDH) is challenging. We retrospectively analysed the outcome of 28 patients (30 hips) with DDH who underwent revision total hip replacement (THR) in the presence of a deficient proximal femur, which was reconstructed with an allograft prosthetic composite. The mean follow-up was 15 years (8.5 to 25.5). The mean number of previous THRs was three (1 to 8). The mean age at primary THR and at the index reconstruction was 41 years (18 to 61) and 58.1 years (32 to 72), respectively. The indication for revision included mechanical loosening in 24 hips, infection in three and peri-prosthetic fracture in three. Six patients required removal and replacement of the allograft prosthetic composite, five for mechanical loosening and one for infection. The survivorship at ten, 15 and 20 years was 93% (95% confidence interval (CI) 91 to 100), 75.5% (95% CI 60 to 95) and 75.5% (95% CI 60 to 95), respectively, with 25, eight, and four patients at risk, respectively. Additionally, two junctional nonunions between the allograft and host femur required bone grafting and plating. An allograft prosthetic composite affords a good long-term outcome in the management of proximal femoral bone loss in revision THR in patients with DDH, while preserving distal host bone.     

Clinical and radiological evaluation of revision hip arthroplasty using the cement-in-cement technique

We reviewed 44 consecutive revision hip replacements in 38 patients performed using the cement-in-cement technique. All were performed for acetabular loosening in the presence of a well-fixed femoral component. The mean follow-up was 5.1 years (2 to 10.1). Radiological analysis at final follow-up indicated no loosening of the femoral component, except for one case with a continuous radiolucent line in all zones and peri-prosthetic fracture which required further revision. Peri-operative complications included nine proximal femoral fractures (20.4%) and perforation of the proximal femur in one hip. In five hips wiring or fixation with a braided suture was undertaken but no additional augmentation was required. There was an improvement in the mean Japanese Orthopaedic Association score from 55.5 (28 to 81) pre-operatively to 77.8 (40 to 95) at final follow-up (p < 0.001). Revision using a cement-in-cement technique allows increased exposure for acetabular revision and is effective in the medium term. Further follow-up is required to assess the long-term results in the light of in vitro studies which have questioned the quality of the cement-in-cement bond.     

可延长假体在儿童恶性骨肿瘤保肢术中的应用

目的 探讨可延长假体在儿童恶性骨肿瘤保肢术中的初步应用效果.方法 回顾性分析2002年1月至2007年12月我科收治的22例原发性恶性骨肿瘤患儿,应用可延长假体开展保肢手术.女11例,男11例;平均年龄10.7(6～13)岁.部位:股骨下段18例,胫骨上段3例,股骨上段1例.骨肉瘤20例,尤文肉瘤2例,Enneking分期均为ⅡB期.所有患儿均术前穿刺活检以明确诊断,并接受规范的新辅助化疗.结果 22例患儿均获得随访,生存患儿平均随访37.63(24～86)个月,局部复发率为4.55%(1/22),肺转移发生率为18.18%(4/22),1例死于术后化疗并发症.术后14例患儿共延长34次,每次延长约1cm,得以延长的患儿双下肢基本等长,长度差平均为0.4(0～1.0)cm.参照国际骨与软组织肿瘤协会(MSTS)功能评估标准,最终MSTS评分平均为76.67%(23/30).配对t检验显示延长组患儿延长前后患肢功能差异无统计学意义.术后假体相关并发症:假体周围感染1例,膝关节倾斜、假体松动下沉和皮下感染各1例.结论 在儿童保肢手术中应用可延长假体的初步结果显示,其既能重建广泛切除肿瘤后的骨缺损,又能解决切除儿童骨骺引发的肢体不等长,具有良好的临床应用前景.     

定制肿瘤型关节假体髓外柄断裂的有限翻修技术

 目的 介绍定制肿瘤型关节假体髓外柄断裂的有限翻修方法,并评价其临床应用效果。方法 3例患者行定制肿瘤型关节假体置换术后发生假体髓外柄断裂,男2例,女1例;年龄分别为25岁、51岁和52岁。原发肿瘤部位及病理组织学类型分别为股骨远端骨肉瘤、股骨远端复发性骨巨细胞瘤及股骨近端软骨肉瘤。假体髓外柄断裂分别发生于术后11个月、34个月和28个月,均无明显外伤史,为行走时发生假体断裂。假体断裂处位于股骨远端假体髓外柄结合部和股骨近端假体的股骨颈基底部。依据假体断裂后髓内柄固定牢固及髓外柄残留足够长度的情况,为避免常规翻修手术中较困难的原假体髓内柄及骨水泥取出,设计了股骨近端和远端翻修假体进行有限翻修,该翻修假体由套筒部和关节部组成,材质及关节部外形与原假体相同,翻修时保留原假体髓内柄,将翻修假体套接于残留的髓外柄,骨水泥及挤压螺钉固定,同时更换磨损的配件,从而完成有限翻修。术后常规功能锻炼,定期随访观察翻修假体稳定性及肢体功能恢复情况。结果 3例患者假体断裂原因为股骨远端假体髓外柄结合部、股骨近端假体股骨颈基底部疲劳断裂各1例,股骨远端假体髓外柄结合部松动、锁钉断裂1例。翻修术后分别随访1个月、103个月和110个月,1例骨巨细胞瘤患者发生软组织内肿瘤复发而再行肿瘤切除术。至末次随访时,3例患者翻修假体固定牢固、无松动。MSTS评分肢体功能评分分别为66.7%、86.7%和83.3%。结论 定制肿瘤型关节假体由于疲劳或结构失效可发生断裂,套接式翻修假体可保留固定牢固的原假体髓内柄而行有限翻修,降低了手术难度,有利于肢体功能的尽快恢复。     

Revision of the Kotz type of tumour endoprosthesis for the lower limb

In 251 patients over a period of 15 years an uncemented Kotz modular femoral and tibial reconstruction mega prosthesis was implanted after resection of a malignant tumour of the lower limb. Twenty-one patients (8.4%) underwent revision for aseptic loosening, again using an uncemented prosthesis, and five of these required a further revision procedure. The median follow-up time from the first revision was 60 months (11 to 168) and after a second revision, 33 months (2 to 50). The probability of a patient avoiding aseptic loosening for ten years was 96% for a proximal femoral, 76% for a distal femoral and 85% for a proximal tibial implant. At the time of follow-up all radiographs were assessed according to the International Symposium of Limb Salvage criteria. The first radiological signs of aseptic loosening were always seen at the most proximal or distal part of the anchorage stem at a mean of 12 months (4 to 23) after the first implantation. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed a mean of 88% of normal function.     

Femoral revision with the Wagner SL revision stem : evaluation of one hundred and twenty-nine revisions followed for a mean of 4.8 years.

BACKGROUND: It is difficult to achieve a successful revision total hip replacement when a patient has severe proximal femoral bone loss. The Wagner SL revision stem has some theoretical advantages, but the durability of this prosthesis is not known. METHODS: We reviewed the results of 129 revisions of the femoral component with a Wagner SL revision stem in 123 patients. The indication for revision was aseptic loosening in ninety-seven hips, periprosthetic fracture in thirteen (one of which also had an infection), and septic loosening in sixteen. In the three remaining hips, a Wagner revision stem was inserted during a second-stage reimplantation after the performance of a Girdlestone resection arthroplasty to treat chronic deep infection. The prerevision defects were classified with the system described by Pak et al. as well as with our system. A functional evaluation of the patients and a survival analysis of the revision stems were performed. RESULTS: The mean duration of follow-up was 4.8 years (range, two months to 11.1 years). Six revision stems required repeat revision. With removal of the stem for any cause or the worst case (removal of the stem for any cause and/or lost to follow-up) as the end point, cumulative survival at 11.1 years was 93.9% and 92.8%, respectively. The mean Merle d'Aubigné score improved from 7.7 points preoperatively to 14.8 points at the latest follow-up examination. The most recent radiographs showed good or excellent restoration of the proximal part of the femur in 113 hips (88%). CONCLUSIONS: Because of the encouraging results of implantation of this femoral component with distal fixation, we will continue to use it in the majority of femoral revisions. However, the need for regular follow-up remains, since the rate of complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture, and late infection may increase in the future.     

Extensible endoprostheses for bone tumors of the proximal femur in children

Between 1983 and 1996, nine children were treated with extensible endoprosthetic replacements of the proximal femur after resection of primary bone tumors. Four patients died of their disease. The remaining five patients were observed for an average follow-up period of 7.6 years. In these five patients, the authors performed an average of 10.2 operations per patient, including five lengthenings and a mean total extension of 69.7 mm per patient. Acetabular loosening and hip dislocations were the most frequent complications. Only two patients have not had a revision or a major complication. Despite this, four children are alive with a functioning lower limb and a mean Musculoskeletal Tumor Society functional score of 77.6%. Extensible endoprosthesis of the proximal femur is a viable alternative to hip disarticulation and in selected children offers an opportunity for near-normal development of the lower limb by allowing equalization of limb length and the ability to walk without the use of mobility aids.     

Long-term followup of uncemented tumor endoprostheses for the lower extremity.

Between 1982 and 1989, 100 primary lower limb reconstructions were done using the Kotz Modular Femur Tibia Reconstruction System after resection of a malignant tumor. In 32 patients a proximal femur prosthesis was implanted, in 40 patients a distal femur prosthesis was implanted, in 19 patients a proximal tibia component was implanted, in four patients a total femur prosthesis was implanted, and in five patients a total knee prosthesis was implanted. The Kaplan-Meier estimate of the overall survival rate of the prostheses was 85% after 3 years, 79% after 5 years, and 71% after 10 years. The most common reason for implant failure was aseptic loosening in 27% of patients (11 patients; range, 10-121 months) after the initial operation. The other reasons for revision surgery were implant fracture (n 5 4) and infection (n 5 4). Early repair of prostheses-related minor complications, such as worn polyethylene bushings, resulted in a statistically significant reduction of implant failure. After a median followup of 127.5 months after the initial surgery, 51 patients had died and eight patients were lost to followup. Forty-one patients were evaluated clinically and radiologically using the Musculoskeletal Tumor Society score and the radiologic implant evaluation system of the International Symposium on Limb Salvage; these 41 patients had a mean of 80% (range, 40%-100%) of the normal functional capability.     

Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty

BACKGROUND: Periprosthetic femoral fractures following total hip arthroplasty are becoming more prevalent. When a fracture occurs in a femur with substantial proximal bone deficiency, the surgical options for revision are limited. One option includes the use of a proximal femoral allograft. METHODS: We retrospectively assessed the results and complications of the use of a proximal femoral allograft to treat twenty-five Vancouver type-B3 periprosthetic fractures in twenty-four patients. The mean duration of follow-up was 5.1 years. Clinical results were graded with use of the Harris hip score. Radiographs were assessed for evidence of trochanteric union, host-allograft union, allograft resorption, and component loosening or fracture. Failure of the procedure was defined as the need for revision surgery requiring graft removal. RESULTS: The mean postoperative Harris hip score was 70.8. At the time of the final follow-up, twenty-one of the twenty-four patients reported no or mild pain and twenty-three patients were able to walk; fifteen required a walking aid. The greater trochanter united in seventeen of the twenty-five hips, and osseous union of the allograft to the host femur occurred in twenty hips. There was mild graft resorption in four hips and moderate graft resorption in two. Four (16%) of the twenty-five hips required repeat revision. CONCLUSIONS: The use of a proximal femoral allograft for the treatment of a Vancouver type-B3 periprosthetic femoral fracture can provide a satisfactory result in terms of pain relief and function at five years.     

Are Complications Associated With the Repiphysis? Expandable Distal Femoral Prosthesis Acceptable for Its Continued Use?

Background

Reconstruction of the distal femur after resection for malignant bone tumors in skeletally immature children is challenging. The use of megaprostheses has become increasingly popular in this patient group since the introduction of custom-made, expandable devices that do not require surgery for lengthening, such as the Repiphysis^® Limb Salvage System. Early reports on the device were positive but more recently, a high complication rate and associated bone loss have been reported.

Questions/purposes

We asked: (1) what are the clinical outcomes using the Musculoskeletal Tumor Society (MSTS) scoring system after 5-year minimum followup in patients treated with this prosthesis at one center; (2) what are the problems and complications associated with the lengthening procedures of this implant; and (3) what are the specific concerns associated with revision of this implant?

Methods

At our institute, between 2002 and 2007, the Repiphysis^® expandable prosthesis was implanted in 15 children (mean age, 8 years; range, 6–11 years) after distal femoral resection for malignant bone tumors. During this time, the general indication for use of this implant was resection of the distal femur for localized malignant bone tumors in pediatric patients. Alternative techniques used for this indication were modular prosthetic reconstruction, massive (osteoarticular or intercalary) allograft reconstruction, or rotationplasty. Age and tumor extension were the main factors to decide on the surgical indication. Of the 15 patients who had this prosthesis implanted during reconstruction surgery, five died with the implant in situ or underwent amputation before 5 years followup and the remaining 10 were evaluated at a minimum of 5 years (mean, 104 months; range, 78–140 months). No patients were lost to followup. These 10 patients were long-term survivors and underwent the lengthening program. They were included in our study analysis. The first seven lengthening procedures were attempted in an outpatient setting; however, owing to pain and burning sensations experienced by the patients, the procedures failed to achieve the desired lengthening. Therefore, other procedures were performed with the patients under general anesthesia. We reviewed clinical data at index surgery for all 15 patients. We further analyzed the lengthening procedures, implant survival, radiographic and functional results, for the 10 long-term survivors. Functional results were assessed according to the MSTS scoring system. Complications were classified according to the International Society of Limb Salvage (ISOLS) classification system.

Results

Nine of the 10 survivors underwent revision of the implant for mechanical failure. They had a mean MSTS score of 64% (range, 47%–87%) before revision surgery. At final followup the 10 long-term surviving patients had an average MSTS score of 81% (range, 53%–97%). In total, we obtained an average lengthening of 39 mm per patient (range, 17–67 mm). Exact expansion of the implant was unpredictable and difficult to control. Nine of 10 of the long-term surviving patients underwent revision surgery of the prosthesis—eight for implant breakage and one for stem loosening. At revision surgery, six patients had another type of expandable prosthesis implanted and three had an adult-type megaprosthesis implanted. In five cases, segmental bone grafts were used during revision surgery to compensate for loss of bone stock.

Conclusions

We could not comfortably expand the Repiphysis^® prosthesis in an outpatient setting because of pain experienced by the patients during the lengthening procedures. Furthermore, use of the prosthesis was associated with frequent failures related to implant breakage and stem loosening. Revisions of these procedures were complex and difficult. We no longer use this prosthesis and caution others against the use of this particular prosthesis design.

Level of Evidence

Level IV, therapeutic study.     

Three-dimensional custom-designed cementless femoral stem for osteoarthritis secondary to congenital dislocation of the hip

A clinical and radiological study was conducted on 97 total hip replacements performed for congenital hip dislocation in 79 patients between 1989 and 1998 using a three-dimensional custom-made cementless stem. The mean age at operation was 48 years (17 to 72) and the mean follow-up was for 123 months (83 to 182). According to the Crowe classification, there were 37 class I, 28 class II, 13 class III and 19 class IV hips. The mean leg lengthening was 25 mm (5 to 58), the mean pre-operative femoral anteversion was 38.6 degrees (2 degrees to 86 degrees ) and the mean correction in the prosthetic neck was -23.6 degrees (-71 degrees to 13 degrees ). The mean Harris hip score improved from 58 (15 to 84) to 93 (40 to 100) points. A revision was required in six hips (6.2%). The overall survival rate was 89.5% (95% confidence interval 89.2 to 89.8) at 13 years when two hips were at risk. This custom-made cementless femoral component, which can be accommodated in the abnormal proximal femur and will correct the anteversion and frontal offset, provided good results without recourse to proximal femoral corrective osteotomy.