Effects and Complications of Hip Arthroplasty After Failure of Internal Fixation in Stable and Unstable Intertrochanteric Femoral Fractures.

Objective: Conversion to hip arthroplasty (cHA) is a widely utilized and effective surgical intervention for addressing the failure of internal fixation in intertrochanteric femoral fractures (FIF-INF). Although previous studies have confirmed that the failure rate of internal fixation is higher in unstable intertrochanteric femoral fractures, but whether the efficacy and complications of cHA after failure differ from those in stable fractures remains unclear. This study aimed to evaluate and compare the clinical and radiological outcomes, as well as the incidence of complications associated with hip arthroplasty over a minimum follow-up period of 3 years after the failure of internal fixation in both stable and unstable intertrochanteric femoral fractures.

Methods: This multicenter study retrospectively analyzed patients who underwent hip arthroplasty subsequent to the failure of FIF-INF from December 2012 to December 2020 at various participating research centers. Cases demonstrating excellent and acceptable quality fracture reduction, as defined by the criteria established by Chang et al., were included. According to AO/OTA classification criteria of intertrochanteric fractures, the fractures were classified into stable fractures (31-A1) and unstable fractures (31-A2, A3). There were 47 patients with stable fractures and 56 patients with unstable fractures. Clinical and radiological evaluations were conducted for all patients. This study employed independent samples t-tests, χ² tests or Fisher's exact test, and both univariate and multivariate logistic regression analyses.

Results: A total of 103 patients were analyzed. The HHS in the stable group improved from a preoperative mean of 47.08 ± 5.50 to 89.13 ± 4.75 at the final follow-up, whereas that in the unstable group increased from 45.43 ± 6.36 to 83.87 ± 4.67. The improvement scores for the stable and unstable groups were 42.05 ± 4.69 and 38.81 ± 3.06, respectively, with a statistically significant difference (p < 0.0001). VAS scores decreased from the preoperative levels of 7.13 ± 0.92 and 7.61 ± 0.82 to 2.36 ± 0.87 and 2.91 ± 0.79, respectively, indicating a significant reduction in pain in both groups; however, the unstable group reported more severe postoperative pain (p = 0.001). The incidence of postoperative complications following cHA was significantly greater in the unstable group (28.57%) than in the stable group (10.64%) (p = 0.047).

Conclusion: cHA is an effective treatment modality for the failure of internal fixation in intertrochanteric femoral fractures. Compared with stable fractures, patients with initial unstable fractures that have failed experience a greater incidence of postoperative complications, relatively poorer joint function, and more pronounced pain following cHA.