Abstract
Objective: We compared intraoperative joint stability between the direct anterior approach (DAA) and the posterolateral approach (PLA) in total hip arthroplasty (THA).
Methods: In 59 patients undergoing primary THA (DAA group: 23 patients, PLA group: 36 patients), intraoperative posterior stability was evaluated by measuring the maximum range of internal rotation (IR) with or without subluxation in various positions of flexion and adduction. Anterior stability also was evaluated by measuring the range of external rotation (ER) in flexion 0° and adduction 0°. The ratio of subluxation in each position was calculated.
Results: The posterior stability was evaluated, and in flexion 45° and adduction 0°, the range of IR was 71.1°±12.1° (average±SD) in the DAA group and 70.1°±9.5° in the PLA group. In flexion 90° and adduction 0°, the range of IR was 55.5°±7.5° in the DAA group and 52.9°±12.3° in the PLA group. In flexion 90° and adduction 20°, the range of IR in the DAA group (47.0°±9.6°) was lower than that in the PLA group (41.1°±12.7°), although the difference was not statistically significant. The ratio of subluxation was significantly lower in the DAA group than in the PLA group in each position. The anterior stability was also evaluated, and the range of ER in the DAA group (45.7°±9.0°) was significantly greater than that in the PLA group (34.8°±7.8°); the ratio of subluxation was also significantly greater in the DAA group.
Conclusion: We compared intraoperative joint stability between the DAA group and PLA group in patients undergoing THA. DAA was suggested to be useful for improving posterior stability. Further studies on the level of anterior stability in both approaches are needed.
