Osteoarthritis is associated with increased failure of proximal femoral fracture fixation.

PURPOSE: The purpose of this study was to evaluate whether the presence of hip osteoarthritis at the time of hip fracture increases treatment failure rates when using either a sliding hip screw (SHS) or proximal femoral nail (PFN) for fracture fixation. METHODS: A retrospective study of a consecutive series of 455 women and 148 men (median age, 83.8 years) treated with SHS or PFN was performed. Osteoarthritis was evaluated based on pre-operative radiographs using the Kellgren and Lawrence grading system. Treatment failure, which was defined as non-union, avascular necrosis, backing out of the implant, cut out of the proximal screws, peri-prosthetic fracture, implant breakage, or conversion to hemi- or total hip arthroplasty, was evaluated for a follow-up period of four to seven years. Optimal placement of the implant (tip-apex distance (TAD) and 3-point fixation) and the effects of age, sex, the quality of reduction, implant type, fracture stability, fracture type, and time to failure were considered confounders of the relationship between failure and osteoarthritis (OA). RESULTS: Among the 32 cases (5.3%) of treatment failure, 12 (2%) showed evidence of osteoarthritis. After controlling for age, sex, the quality of reduction, implant type, fracture stability, fracture type, and TAD, osteoarthritis was associated a greater than threefold increase in treatment failure compared with that of patients without pre-operative evidence of osteoarthritis (OR, 3.26; 95% CI, 1.4-7.65; P = 0.006). CONCLUSIONS: After adjusting for potential confounding factors, radiographic evidence of hip osteoarthritis at the time of hip fracture increases the incidence of treatment failure.

Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study.

BACKGROUND: Unstable proximal femoral fractures are common and challenging for the orthopaedic surgeon. Often, these are treated with intramedullary nails. The most common mode of failure of any device to treat these fractures is cut-out. The Synthes proximal femoral nail antirotation (PFNA) is unique because it is the only proximal femoral intramedullary nail which employs a helical blade in lieu of a lag screw. The optimal tip-apex distance is 25 mm or less for a dynamic hip screw. The optimal blade tip placement is not known for the PFNA. AIM: The aim of this study is to determine if the traditional tip-apex distance rule (<25 mm) applies to the PFNA. METHOD: A retrospective study of all proximal femoral fractures treated with the PFNA in Western Australian public teaching hospitals between August 2006 and October 2007 was performed. Cases were identified from company and theatre implant use records. Patient demographic data was obtained from hospital records. Fractures were classified according to Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation. Fracture reduction, distal locking type and blade position within the head (tip-apex distance and Cleveland zone) were recorded from the intraoperative and immediate postoperative radiographs. Postoperative radiographs obtained in the routine treatment of patients were studied for review looking primarily for cut-out. Clinical outcomes were measured with the Oxford hip score. RESULTS: One hundred eighty-eight PFNAs were implanted during the study period, with 178 cases included in this study. Ninety-seven patients could be followed up clinically. There were 18 surgical implant-related failures (19%). The single most common mode of failure was cut-out in six cases (6.2%). Three cut-outs (two medial perforation and one varus collapse) occurred with tip-apex distance (TAD) less than 20 mm. There was no cut-out in cases where the TAD was from 20-30 mm. There were three implant-related failures (nail fracture, missed nail and loose locking screw), four implant-related femoral fractures, two non-unions, two delayed unions and one loss of reduction. CONCLUSION: The PFNA is a suitable fixation device for the treatment of unstable proximal femoral fractures. There were still a relatively large number of cut-outs, and the tip-apex distance in the failures showed a bimodal distribution, not like previously demonstrated with dynamic hip screw. We propose that the helical blade behaves differently to a screw, and placement too close to the subchondral bone may lead to penetration through the head.