Conversion total hip arthroplasty with a proximally modular, distal fixation reconstruction prosthesis following cephalomedullar nail failure

Background: The goals of intertrochanteric hip fracture (IHF) treatment are stable fixation, early mobilisation and function restoration. If the attempt to reduce, stabilise and fracture healing utilising a femoral cephalomedullar nail (CMN) fails, options for subsequent attempts are limited. Purpose: Evaluate the clinical and radiographic outcomes of conversion total hip arthroplasty (THA) using a modular stem following a CMN failure. Materials and methods: We retrospectively reviewed a consecutive series of patients with an IHF between 2012 and 2014 to identify CMN patients that went on to the subsequent failure and conversion to THA utilising a modular femoral stem (MFS). In all cases, MP Reconstruction Prosthesis (Waldemar Link, Hamburg, Germany) was implanted. Primary clinical outcomes were assessed using Harris Hip Score (HSS) before conversion procedure, 3 months, 6 months and recent office visit post-conversion THA thereafter. The secondary outcome was to analyse intra and postoperative complications. Serial radiographs at each follow-up interval were assessed for clinical success or to confirm adverse events. Results: 28 patients were included in the study; 17 were females. The average age was 72.7 years (SD +/- 10.5); the average time from the index procedure to conversion THA was 12.6 months (SD +/- 3.5). At baseline, average HHS was 42.1 (SD +/- 3.6), improved to 80.7 (SD +/- 5.1) at 3 months, 86.0 (SD +/- 3.9) at 6-months which levelled off to 86.1 (SD +/- 4.0) at final follow-up. There were 4 (14%) post-conversion complications: 2 dislocations, 1 superficial wound infection, 1 patient with symptomatic abductor deficiency. All 4 cases were conservatively treated successfully, the implants were retained, and the patients progressed without further issue. Conclusions: MFSs allow to successfully treat failed CMN and adverse variations in femoral anatomy with a device that will permit simultaneous correction of leg length, offset and version to relieve pain, restore function and create a durable prosthetic to host composite.