Characteristics of intramedullary nail breakage in pertrochanteric femur fractures: a summary of 70 cases

OBJECTIVE: To reveal noteworthy characteristics of intramedullary (IM) nail breakage in pertrochanteric femur fractures. MATERIALS AND METHODS: The data from 6 patients with IM nail breakage in our hospital between August 2008 and May 2018 were reviewed retrospectively. With an additional 64 cases reported in articles in the PubMed database prior to October 2019, a total of 70 cases were reviewed and analysed; epidemiological patient data and data on the initial trauma, fracture type, nail selected for the original surgery, time from surgery to breakage, mechanism and location of breakage, status of fracture healing, salvage treatment and prognosis were assessed. RESULTS: Seventy patients with pertrochanteric fractures, including 2 stable fractures and 68 unstable fractures, experienced IM nail breakage at a mean of 9.4 months after the initial surgery. Among them, 9 (12.9%) occurred within 3 months, 23 (32.9%) between 3 and 6 months and 38 (54.3%) after 6 months. The mean age was 72.3 years, and 16 (22.9%) patients were younger than 65 years old. When nail breakage occurred, 66 fractures (94.3%) exhibited delayed union/non-union. Self-dynamisation was found in 12 cases (17.1%). The salvage procedures included 4 partial/total implant removal procedures, 17 hemi/total hip arthroplasty procedures, 3 conservative treatment procedures, and 46 revised osteosyntheses, of which 7 cases (15.2%) sustained secondary implant failure. No significant differences were found between the failure rates of IM nails and extramedullary(EM) devices (odds ratio [OR], 3.429; 95% confidence interval [CI], 0.632–18.877; p = 0.330). CONCLUSION: IM nail breakage is a rare complication lack of time regularity and mostly occurs in unstable pertrochanteric fractures in the presence of delayed union/non-union. Osteosynthesis revision can be conduct by a new IM nail or EM device but considerable secondary failure rate is noteworthy. Self-dynamisation may be a warning sign of nail breakage.