Presence of lesser trochanter fragments is a risk factor for malrotation in subtrochanteric femoral fractures: A multicenter, retrospective, observational study

BACKGROUND: Subtrochanteric femoral fractures are challenging injuries that are often associated with complications such as malrotation. Although imaging indicators such as the lesser trochanter sign are commonly used to achieve proper rotational alignment during surgery, their reliability diminishes in the presence of lesser trochanter fragments. This study investigated the relationship between lesser trochanter fragments and rotational deformities in patients treated with antegrade intramedullary nailing for subtrochanteric fractures. METHODS: This multicenter retrospective analysis included 40 patients who underwent surgery for subtrochanteric fractures. Femoral anteversion was measured using preoperative and postoperative computed tomography images. Patients were divided into two groups based on the severity of rotational deformities. Predictive factors were evaluated using univariate and multivariate regression analyses. RESULTS: Lesser trochanter fragments were significantly associated with large rotational deformities (P < 0.001). Among patients in the large deformity group (>9°), 65.0 % had lesser trochanter fragments; however, among patients in the small deformity group (≤9°), only 10.0 % had lesser trochanter fragments. Other factors such as age, sex, operative time, and blood loss were not significantly different between the severe deformity and minor deformity groups. The presence of lesser trochanter fragments was an independent predictor of the absolute value of rotational deformity (P < 0.001) CONCLUSION: The presence of lesser trochanter fragments is a critical risk factor for postoperative rotational deformities. In such cases, visual landmarks are compromised; therefore, we recommend using objective intraoperative verification techniques rather than relying solely on the lesser trochanter shape sign to prevent malalignment.