Reconstruction with a cage outlives patients with metastatic disease involving the acetabulum.

AIM: The aim of this study was to determine whether patients treated with a caged reconstruction for metastatic acetabular disease would have a construct survival superior to that of their life expectancy. PATIENTS AND METHODS: We undertook a retrospective study, in a single centre in the United Kingdom, reviewing outcomes for 19 patients (20 hips) treated with a cage reconstruction for metastatic disease of their acetabulum over 6 years. Inclusion criteria were those with an impending fracture of the acetabulum, metastatic dissociation, fracture of the acetabulum and or femur and those whose life expectancy was considered by the oncology team to be >6 months. RESULTS: In all patients the Restoration GAP II acetabular cage (Stryker, Howmedica Osteonics Corp, NJ, USA) was used in conjunction with a cemented acetabular cup and cemented femoral stem. The mean age at the time of surgery was 68 (44-87) years with breast cancer being the most common primary malignancy (31%) followed by prostate cancer (26%).Radiological survivorship estimates were 94.1% (95% CI, 99.2-65.0) at 12 and 24 months, 70.6% (95% CI, 93.6-16.0) at 36 months and 35.3% (95% CI, 78.2-1.2) at 48 months. There were 3 radiological failures of the implant due to disease progression. Complications occurred in 3 patients with 2 developing deep infection which was treated with suppressive antibiotic therapy following aspiration of the hip. 1 patient suffered a hip dislocation following trauma which was successfully reduced closed and no further intervention was required. CONCLUSIONS: This study represents the first published case series of the use of the GAP II cage in patients with metastatic acetabular disease. The construct generally outlives the patient and hence is suitable for the treatment of acetabular metastases.

Cement-a-TAN Temporary Proximal Femoral Replacement for Staged Joint Replacement - A Case Report.

INTRODUCTION: Infected non-unions of proximal femoral fractures are difficult to treat. If debridement and revision fixation is unsuccessful, staged revision arthroplasty may be required. Non-viable tissue must be resected; coupled with the introduction of an antibiotic-eluting temporary spacer before definitive reconstruction. Tissue microbiological diagnosis and targeted antibiotic therapy are required. In cases of significant proximal femoral bone loss, spacing options are limited. CASE REPORT: We present a case of a bisphosphonate-induced subtrochanteric fracture that progressed to infected non-union. Despite multiple washouts and two revision fixations, the infection remained active with an unfavorable antibiogram. The patient required staged revision arthroplasty including a proximal femoral resection. To improve function through maintaining leg length and offset, the Cement-a-TAN was fabricated. It is a custom-made antibiotic-eluting articulating temporary spacer. Using a trochanteric entry cephalocondylar nail as a scaffold, bone cement was molded around the nail to fashion an anatomical and patient-specific proximal femoral spacer. Following resolution of the infection, the Cement-a-TAN was removed and a proximal femoral arthroplasty was successfully performed. CONCLUSION: Cement-a-TAN is an excellent temporary spacing technique in staged proximal femoral replacement for infected non-union of the proximal femur where there has been significant bone loss. It preserves mobility and maintains leg length, offset, and periarticular soft-tissue tension, while offering good stability.

A comparison of the validity and reliability of established bone stock loss classification systems and the proposal of a novel classification system.

The classification and management of aseptic loosening of total hip arthroplasty remains a distinct challenge to the modern orthopaedic surgeon. The aim of this study was to assess the inter-observer and intra-observer reliability of commonly used classification systems for the assessment of bone stock loss in revision hip surgery. Radiographs of 23 femoral and 32 acetabular components in 30 patients were assessed using the Paprosky, AAOS and Endo-Klinik classification systems. A novel classification system was introduced and also used to assess the radiographs. Assessment was undertaken by 3 surgeons on 2 separate occasions and the inter- and intra- observer reliability calculated. The novel classification system showed a good to very good intra-observer reliability for both femoral and acetabular components (0.77-1.0; p<0.001), performing better than the other systems assessed. The novel femoral system demonstrated moderate to good inter-observer agreement (0.46-0.73), performing as well as the Paprosky (0.63-0.80) and AAOS (0.63-0.68) femoral systems. The novel acetabular system demonstrated fair to moderate inter-observer reliability (0.35-0.51) performing better than the AAOS acetabular classification (0.07-0.10) and as well as the Paprosky acetabular classification system (0.59-0.60). We propose this novel system as an alternative method for assessing bone stock loss in revision hip surgery.