BIOMECHANICS OF THE HIP JOINT IN GOLFERS WITH A HISTORY OF HIP LABRAL TEARS

Abstract

Hip labral tears among golfers are becoming more recognized and effectively treated. These injuries are likely caused by repetitive stress placed on the soft tissue of the hip during the golf swing. PURPOSE To determine if golfers with a hip labral tear demonstrate different kinematic and kinetic characteristics of the injured hip during the golf swing. METHODS Ten healthy golfers (handicap: 9.5 ± 7.3; BW 825 ± 151N; HT 1.77±.07m) and 5 golfers (handicap: 12.4 ± 7.6; BW 790 ± 182N; HT 1.76±.10m) with a labral tear of the right hip participated in the study. All golfers were right handed. Two injured golfers were pre-surgery while 3 had surgery to excise the torn labrum. A 3D biomechanical analysis of the golf swing was performed using a 6 camera, 120 Hz kinematics system interfaced with 2 force plates. Joint angles, forces, and moments of the right hip were evaluated at the top of the backswing (TBS), middle of the downswing (MDS), and at ball impact (BI). A Mann-Whitney nonparametric test was used to compare group differences (± = .05). RESULTS At TBS, injured golfers generated less hip abduction moment (3.1 ± 2.7% vs 6.1 ± 1.8% BW*HT). At BI, injured golfers had less abduction than did the healthy golfers (16.4 ± 3.2± vs 21.5 ± 4.2±). No other significant differences were found. Injured golfers tended to have more flexion (17.4 ± 12.2± vs 12.3 ± 8.5±, p = .22) at TBS and compressive force in MDS (59.0 ± 24.5% vs 48.7 ± 5.9% BW, p = .28). CONCLUSION Frontal plane differences were noted between the healthy and injured golfers. It is not known whether these differences contributed to or resulted from the injury. A plausible hypothesis for the etiology of the labral tear may be that a decreased abduction moment and increased sagittal plane motion at TBS and decreased abduction at BI are related to an increased compressive force in the downswing that may cause the hip labral tear after repetitive microinjury.