Abstract
We report the case of a 30-year-old patient initially treated for a proximal femoral Ewing's sarcoma when 12 years old. Index treatment comprised tumour resection and total hip arthroplasty. Two years later revision for aseptic loosening was performed. Subsequently, six further surgical revisons were performed for varying causes. At the age of 23 years the proximal femur was resected and a proximal femoral endoprosthesis implanted.
Eighteen years after initial diagnosis the patient presented with recurrent aseptc loosening. Both the proximal femur and acetabulum were reconstructed. For acetabular reconstruction a structural allograft and a tantalum cup were utilised. Reconstruction of the femur utilsed extensive wire mesh and circlage wiring with impaction bone allograft into which a femoral stem was implanted.
At one-year follow-up the patient was pain free, had no evidence of infection with satisfactory radiographs and no evidence of implant loosening. This is the first case reporting an extended proximal femoral reconstruction with a wire mesh in combination with impaction bone grafting in an aseptic loosened proximal femoral replacement following Ewing's Sarcoma.
Keywords
Introduction
As the need for total hip arthroplasty increases, the incidence of extensive proximal femoral bone loss will increase as a consequence of massive osteolysis, stress shielding and multiple revisions (1–2–3–4–5). Proximal femoral bone stock deficiency provides a major challenge for revision hip arthroplasty and is likely to account for a significant future caseload (6). Various surgical techniques have been advocated including impaction bone grafting (7, 8), distal press-fit fixation (9, 10) and massive endoprosthetic reconstruction (11–12–13). Individual studies have reported a 58% to 84% survivorship of endoprosthetic reconstruction (or megaprostheses) with an average follow-up ranging from five to ten years (11–12–13). A recent retrospective review of 403 proximal femoral replacements from five institutions reported a 10- and 15-year survival rate of 75%, with mechanical causes being the most common mode of failure (14).
If megaprostheses fail due to proximal bone deficiency, proximal allograft reconstruction may be an alternative to total femoral replacement, especially in young patients (15). We report a surgical technique to reconstruct the proximal femur with a wire mesh and impaction allogenic bone grafting. The clinical outcome at one-year follow-up is reported.
Case Report
In February 2011 a 28-year-old male patient presented to our institution with severe pain and impared mobility due to a loosened left MUTARS tumour-proximal femoral replacement. In 1994 at an age of 12 years the patient was first diagnosed with Ewing's sarcoma of the proximal left femur. At that time the tumour was radically resected and a total hip arthroplasty (THA) perfomed. The patient was additionally treated with adjuvant chemoradiotherapy.
Two years later a two-stage exchange of the THA due to a periprosthetic joint infection with staphylococcus epidermidis was performed. During revision the proximal femur was resected and a proximal femoral endoprosthesis implanted.
Fifteen years later the patient presented to our institution, with left calf pain and 8 cm shortening of the left leg. The Harris Hip Score (HHS) was 22. Radiographs showed both evidence of both implant loosening (Fig. 1) and a severe bone defect of the proximal femur (Type IV according to the classification system of Paprosky). Results of joint aspiration yielded no evidence of infection.
Preoperative radiograph of the pelvis with severe bone loss and distinctive signs of loosening and subsidence.
During one-stage revision surgery the implant was removed and extensive tissue debridement perfomed (Fig. 2a). Acetabular reconstruction utilised a structural allograft graft fixed with two traction screws and a tantalum cup augmented with two central screws. The distal femur was filled and impacted with bone flakes. Then the middle third of the femur, where only one third of the former circumference remained, was reconstituted using wire mesh held by three circlage wires (Fig. 2b). Allogenic bone chips were then impacted into the reconstructed femur (Fig. 2c), followed by cementing of the stem of a modular prosthesis (MP, Waldemar LINK, Germany) with Copal-Cement (Fig. 2d).
Intraoperative pictures: a) after debridement of the femoral stem; b) proximal femoral reconstruction using a wire gauze and three wire cerclages; c) bone impaction grafting; d) after cementing the prosthesis using a modular revision stem (MP) by Link Company.
Postoperatively, the patient was mobilised starting on day two after surgery with restricted weight bearing of 10 kg for six weeks. Full weight bearing was allowed after ten weeks.
At one-year post surgery HHS was increased to 63, the patient had no analgesic requirements and was able to walk short distances independently but required walking stick for longer distances. Residual leg length discrepancy was managed with a shoe-raise. Follow-up x-rays were satisfactory with no evidence of loosening or subsidence and good bone graft incorporation (Fig. 3).
Postoperative radiograph of the pelvis follow up one year after operation.
Discussion
Technological and surgical innovations have resulted in improved implant survival in patients undergoing primary THA (4). Despite this and in parallel however, the burden of revision THA is expected to substantially increase (16) and predicted to expand by 137% between the years 2005 and 2030, with an estimated 100000 cases in the United States in 2030 (17). In this context femoral impaction bone allografting has been utilised to restore bone stock in revision total hip arthroplasty. As the technique of femoral impaction bone grafting has evolved, so the reported results in terms of clinical outcome and survivorship have also improved (18–19–20–21–22).
Buttaro et al (15) reported the outcome of 14 patients with 15 hips, all of them with severe femoral bone loss (Type IIIb-IV Paprosky). The study shows a survival rate of 100% after one and 86% after six years of follow-up.
Alternative treatment options in cases of severe bone deficiency of the proximal femur are limited. Options are limited and include implantation of another customised lengthening tumour prosthesis, a distally fixed cemented long stem or a total femur replacement.
The current literature is equivocal in that both revision procedures using megaprostheses or allograft transplants show similar outcomes (23, 24). Both procedures present an alternative treatment in case of failure of our procedure.
Overall, studies reporting cemented fixation into the distal host bone have shown a higher rate of aseptic loosening or fracture when compared to uncemented distal fixation. Whilst differences were not statistically significant, the benefit of uncemented distal fixation includes the reduced risk of junctional nonunion between the host femur and allograft (25). However, the optimal stem design for use with impaction grafting remains controversial (26). Currently it is not possible to conclude from the literature, whether a long or a short stem should be used with impaction grafting (27, 28) but there is evidence that the addition of strut allografts may provide mechanical stability and increase bone stock (29, 30).
Another possible solution in this clinical setting is a total femoral replacement. Friesecke et al (31) reports the early outcome (mean 5 years) of 100 patients with total femoral replacements. They reported satisfactory functional results with an overall 68% survival rate, an infection rate of 13% but complications in 22% of cases (including nerve palsy, dislocation, implant fracture and patellar dislocation and pain). The case presented has a high potential risk of reinfection. Reinfection rates after revision arthroplasty surgery ranges from 3.2% to 13% (32–33–34) and especially patients with arthroplasty due to bone malignancies (including the use of neo/adjuvant radiotherapy) show increased infection rates when compared with ‘routine’ arthroplasty indications (35). Such complex cases require expertise in revision surgery, a multidisciplinary approach to treat/exclude infection, extensive and versatile bone bank facilities and the availability of multiple revision arthroplasty implant system. Consequently, complex salvage procedures such as this should only be performed in specialist centres with a multidisciplinary approach and expertise in complex revision arthroplasty surgery.