Treatment of peri-implant refracture after intramedullary nail fixation for intertrochanteric fractures

Abstract

To investigate the occurrence, treatment, and effectiveness of peri-implant refracture after intramedullary nail fixation for intertrochanteric fractures. The clinical data of 16 patients with peri-implant refracture after intramedullary nail fixation for intertrochanteric fractures who met the inclusion criteria between April 2014 and November 2019 were retrospectively analyzed. There were 7 males and 9 females with an average age of 78.4 years (range, 65-93 years). The 14 cases of initial intertrochanteric fractures were classified according to the classification of AO/Orthopaedic Trauma Association (AO/OTA): 5 cases of type A1, 7 cases of type A2, and 2 cases of type A3; the other 2 cases were intertrochanteric combined with subtrochanteric fractures (Seinsheimer type Ⅴ). According to the classification of peri-implant refracture which was proposed by Chan et al., there were 10 cases of type 1 (6 cases of type 1A, 3 cases of type 1B, 1 case of type 1C) and 6 cases of type 2 (4 cases of type 2A and 2 cases of type 2B). The average interval between refracture and initial surgery was 14.6 months (range, 1-52 months). The incidence of peri-implant refracture in short nail group (the length of intramedullary nail used in initial surgery≤240 mm) was 1.92% (11/573), while the incidence of long nail group (the length of intramedullary nail used in initial surgery≥340 mm) was 1.66% (5/301), showing no significant difference between the two groups ( χ 2=0.073, P=0.786). The peri-implant refractures were revised with extended intramedullary nail (5 cases) or fixed with additional limited invasive stabilization system (11 cases). The average operation time was 115.8 minutes (range, 78-168 minutes) and the average intraoperative blood loss was 283.1 mL (range, 120-500 mL). One patient died of myocardial infarction at 3 months after operation, and the other 15 patients were followed up 9-46 months (mean, 16.8 months). The peri-implant refractures healed at 14-20 weeks (mean, 16.4 weeks) after operation. There was no complications such as incision infection, nonunion, internal fixator loosening and rupture, screw cutting-out, and the second refracture during the follow-up. At last follow-up, all injured limbs regained walking function, and the Hospital for Special Surgery (HSS) score was 56-92 (mean, 80.2). The results were classified as excellent in 2 cases, good in 10, fair in 2, and poor in 1, with the excellent and good rate of 80%. Stress concentration at the tip of initial intramedullary nail and distal interlocking screw aera is the main cause of peri-implant refracture after intramedullary nail fixation for intertrochanteric fractures. Revision with extended intramedullary nail or fixation with limited invasive stabilization system according to the length of initial intramedullary nail and the type of refracture can get satisfactory effectiveness.