Purpose To evaluate the accuracy of navigation‐assisted arthroscopic osteochondroplasty by focusing on the total volume and location of residual deformities, specifically by assessing the total amount and areas of residual deformities and determining whether residual cam deformities result in simulated residual impingement in postoperative computed tomography (CT)‐based computer simulations. Methods We analyzed pre‐ and postoperative CT data of patients with cam‐type or combined‐type femoroacetabular impingement who underwent navigation‐assisted arthroscopic osteochondroplasty between November 2022 and May 2024. Preoperative planning included a virtual cam resection simulation to improve internal rotation by 10°. Three‐dimensional models were created using Mimics and 3‐matic software. Residual volume was calculated as a percentage of the planned resection volume, and residual thickness was quantified using a 3‐mm threshold. Postoperative CT simulations at 0° adduction and 90° flexion were used to evaluate residual impingement. Results Of 26 patients (27 hips) who underwent CT‐based navigation‐assisted arthroscopic osteochondroplasty, 4 hips were excluded due to congenital hip disorders, missing planning data, or magnification inconsistencies, leaving 23 hips in 22 patients for analysis. The residual volume was 1149.3 (634.6‐1427.2) mm 3 , accounting for 57.1 (37.4‐67.6)% of the planned resection volume. Areas with a residual thickness >3 mm accounted for 5.4 (1.7‐15.1%). Residual regions were predominantly in the distal lateral area (91.3%) and showed a high concordance with the residual impingement area (κ = 0.72). The planned resection volume was 2113.0 mm 3 (1576.3‐3164.5), and the actual resected volume was 1784.3 mm 3 (1283.1‐2473.9), showing a significant difference ( P = .04). Conclusions Even with navigational assistance, insufficient cam resection and associated residual impingement may persist. The residual volume comprised 57.1% of the planned resection, with regions >3‐mm thick accounting for 5.4%. The distal lateral region had substantial concordance with postoperative impingement areas. Level of Evidence Level IV, retrospective therapeutic case series.
Ogura et al. (Thu,) studied this question.