Evaluation of Stiffness in the Tensor Fasciae Latae and Iliotibial Band After Direct Anterior Approach Total Hip Arthroplasty

Background This study aimed to evaluate postoperative changes in the stiffness of the tensor fasciae latae (TFL) and iliotibial band (ITB) after total hip arthroplasty via the direct anterior approach. Associations with hip alignment, pain, and hip range of motion (ROM) were also investigated. Methods Forty-eight patients (64 hips) undergoing primary total hip arthroplasty from April to November 2023 were included. Shear wave elastography (SWE), an ultrasound-based technique that quantifies tissue stiffness, was used to measure TFL and ITB stiffness preoperatively and daily during the first postoperative week. Changes over time and correlations between SWE values and femoral offset (FO), leg length, pain during gait, and hip ROM were assessed. Results SWE values of the TFL and ITB (higher values indicate greater stiffness) were higher than preoperative values on postoperative days 1–5 (TFL) and 1–4 (ITB) ( P < .01) and were no longer significantly different by postoperative day 6 and postoperative day 5, respectively. Greater FO increase was associated with higher SWE values of the TFL and ITB on postoperative day 1 ( P < .01). Higher SWE values were associated with greater pain during gait on postoperative days 2–7 ( P ≤ .01) and with reduced hip adduction and extension ROM ( P < .05). Conclusions Early postoperative TFL and ITB stiffness were higher than preoperative values. On postoperative day 1, greater FO increase was associated with higher TFL and ITB stiffness. Postoperative stiffness was also associated with greater pain during gait and reduced hip adduction and extension ROM early postoperatively.