Dynamic Hip Kinematics during the Golf Swing after Total Hip Arthroplasty

Background: Although most surgeons allow their patients to play golf after total hip arthroplasty (THA), the effect on the implant during the golf swing is still unclear. Purpose: To evaluate hip kinematics during the golf swing after THA. Study Design: Descriptive laboratory study. Methods: Eleven hips in 9 patients who underwent primary THA were analyzed. All patients were right-handed recreational golfers, and these 11 hips included 6 right hips and 5 left hips. Periodic radiographic images of the golf swing were taken using a flat-panel x-ray detector. Movements of the hip joint and components were assessed using 3-dimensional-to-2-dimensional model-to-image registration techniques. Liner-to-neck contact and translation of the femoral head with respect to the acetabular cup (cup-head translation) were examined. Hip kinematics, orientation of components, and maximum cup-head translation were compared between patients with and without liner-to-neck contact. Results: On average, the golf swing produced approximately 50° of axial rotation in both lead and trail hips. Liner-to-neck contact was observed in 4 hips with elevated rim liners (2 lead hips and 2 trail hips) at maximum external rotation. Neither bone-to-bone nor bone-to-implant contact was observed at any phases of the golf swing in any of the hips. Four hips with liner-to-neck contact had significantly larger maximum external rotation (37.9° ± 7.0° vs 20.6° ± 9.9°, respectively; P =.01) and more cup anteversion (26.5° ± 6.1° vs 10.8° ± 8.9°, respectively; P =.01) than hips without liner-to-neck contact. No significant differences between hips with and without contact were found for cup inclination (42.0° ± 2.5° vs 38.1° ± 5.5°, respectively; P =.22), combined anteversion (45.3° ± 8.9° vs 51.4° ± 7.9°, respectively; P =.26), or maximum cup-head translation (1.3 ± 0.3 mm vs 1.5 ± 0.4 mm, respectively; P =.61). Conclusion: In this analysis, the golf swing did not produce excessive hip rotation or cup-head translation in any hips. However, liner-to-neck contact during the golf swing was observed in 36% of the hips, with unknown effects on the long-term results. Clinical Relevance: Golf is an admissible sport after THA because dynamic hip stability was observed. However, the implant position, especially cup anteversion and the use of elevated rim liners, promoted liner-to-neck contact.