The use of endoprosthesis implants is frequent for tumours involving the proximal third of the femur and not amenable to primary arthroplasty or internal fixation. In this population, these implants are preferentially cemented given poor bone quality associated with systemic diseases and treatments. Loosening is a common complication of these implants that have been linked to poor bone quality, type of implants and importantly cementing technique. Thus, these techniques vary between different surgeons and based mainly on previous experience. One of the most successful cementing techniques in the arthroplasty literature is the French paradox. This technique involves removing the cancellous bone of the proximal femoral metaphysis and selects the largest stem to tightly fit the created cavity delineated by cortical bone. Cementing the implant results in a very thin cement layer that fills the inconsistent gaps between the metal and the bone. To our knowledge, no previous report exists in the literature assessing loosening in proximal femur replacement using the French paradox cementing technique. In this study, we sought to examine (1) rates of loosening in proximal femur replacement, and (2) the oncological outcomes including tumour recurrence and implant related complications. A retrospective study of 42 patients underwent proximal femur replacement between 1990 and 2018 at our institution. Of these, 30 patients met our inclusion criteria. Two independent reviewers have evaluated the preoperative and the most recent postoperative radiographs using the International Society of Limb Salvage (ISOLS) radiographic scoring system and Gruen classification for femoral stem loosening. Additionally, the acetabulum was evaluated for erosion according to the criteria of Baker et al. The mean age of this cohort was 60.5 (19–80), with 60% being males. The primary origin was metastatic in 17 (56.7%) patients, bone sarcoma in 10 (33.3%) patients and soft tissue sarcoma in 3 (10%) patients. Pathological fractures were present in 11 (36.7%) patients. Seven (23.3%) patients had prior intramedullary nailing. Preoperative radiotherapy was used in 8 (26.7%) and postoperative radiotherapy in 17 (56.7%) patients. The mean clinical follow-up was 25.2±26.3 months and the mean radiographical follow-up was 24.8±26 months. The mean ISOLS score for both reviewers was found to be 89±6.5% and 86.5±6.1%, respectively. Additionally, the first reviewer found two patients to be possibly loos (6.7%) compared to one (3.3%) patient for the second reviewer. No components scored as probably or definitely loose and non-required revision for either loosening or metal failure. Furthermore, both reviewers showed no acetabular erosion in 25 (83.3%) and 24 (80%) patients, respectively. On the other hand, the overall rate of complications was 36.6% with 11 complications reported in 30 patients. Local recurrence occurred in five (16.6%) patients. Prosthetic Dislocation was the most frequent complications with eight dislocations in four patients. Despite complications, our results showed no radiographic evidence of stem loosening. Cementing proximal femur prosthesis with a tight canal fit and with a thin cement mantle appears to be a viable option at short and medium term

Abstract. Background. Atypical femur fracture (AFF) is a well known complication of Bisphosphonate therapy. Due to prolonged suppression of bone re-modelling in these fractures, surgical complications are difficult to manage. The aim of this study was to analyze the causes of surgical complications in AFF fixations and provide algorithm for management. Method. In this retrospective 10-year study (2010–2020), we identified patients surgically treated for AFF. We included patients who underwent revision surgery for any cause. Data collection included demographics, surgical complications, details of revision surgery and time to union. Result. Out of 57 patients who were operated for AFF, 17 underwent revision fixation. The average age was 69 with only 2 males. Around two-third (64%) were sub-trochanteric fractures and method of fixation in 64% cases was intra-medullary nail. The most common complication was non-union (12), followed by stress fracture and infection in 3 and 2 cases respectively. In most cases inadequate reduction and sub-optimal fixation was perceived as cause of failure except two cases which got infected. Revision fixation in all cases included improved bone contact (non-union site osteotomy), use of bone morphogenic proteins and improved fixation with augmentation device (either nail or plate). Follow up at 1 year showed fracture union in 12 cases, remaining 5 revision fixations failed, 3 of which were managed with proximal femur replacement. Conclusion. High rate of non-union after fixation in AFF. Optimizing the fixation construct results in union in most cases. However, arthroplasty should be considered in elderly patients with poor bone quality