Abstract
INTRODUCTION
Golf is considered low-impact sport, but concerns exist about whether golf swing can be performed in safe manner after THA. The purpose of this study was to clarify dynamic hip kinematics during golf swing after THA using image-matching techniques.
METHODS
This study group consisted of eight right-handed recreational golfers with 10 primary THAs. Each operation was performed using a posterolateral approach with combined anteversion technique. Nine of ten polyethylene liners used had elevated portion of 15°. Continuous radiographic images of five trail and five lead hips during golf swing were recorded using a flat panel X-ray detector (Fig. 1) and analyzed using image-matching techniques (Fig. 2). The relative distance between the center of cup and femoral head and the minimum liner-to-stem distance were measured using a CAD software program. The cup inclination, cup anteversion, and stem anteversion were measured in postoperative CT data. Hip kinematics, orientation of components, and cup-head distance were compared between patients with and without liner-to-stem contact by Mann-Whitney U test.
RESULTS
At the top of backswing, lead hips showed 26 ± 11° ER, and trail hips showed 24 ± 19° IR. At the end of follow-through, lead hips showed 24 ± 19° IR, and trail hips showed 24 ± 12° ER. The mean cup inclination and anteversion, stem anteversion, and combined anteversion were 40 ± 5°, 18 ± 11°, 33 ± 14°, and 50 ± 8°, respectively. The minimum liner-to-stem distance showed the smallest value of 3 ± 4 mm at the maximum ER. Bone-to-bone and bone-to-implant impingements were not observed in all hips at all phases. The liner-to-stem contact was observed in four hips with elevated liners (two trail and two lead hips; Fig 3). Patients with elevated liner-to-stem contact demonstrated significantly (p < .05) larger maximum ER and larger cup anteversion than patients without contact. The mean cup-head distance was 0.9 ± 0.5 mm of translation. No significant difference was found in the flexion/extension and adduction/abduction at the maximum ER, cup inclination, combined anteversion, and cup-head distance between patients with and without contact.
DISCUSSION
Golf swing produced approximately 50° of axial rotations in both lead and trail hips after THA. The mean cup-head distances showed less than 1.0 mm, and there was no significant difference between patients with and without neck-liner contact. Therefore, we consider that dynamic stability without excessive hip rotations or subluxation was demonstrated during golf swing. Despite no evidence of component malpositioning, elevated liner-to-stem contact was observed in 40% of hips with significantly larger ER and cup anteversion. Because the liner-to-stem contact may be a concern with regard to the long-term prognosis following THA, further attention must be given to the anteversion of the components and the use of elevated liner at the time of surgery.
To view tables/figures, please contact authors directly.
