Original article

Influence of the femoral head size on early postoperative gait restoration after total hip arthroplasty

ZHOU Yi-xin, GUO Sheng-jie, LIU Qing, TANG Jing and LI Yu-jun

Keywords: total hip arthroplasty; femoral head; Harris Hip Score; gait analysis 北京积水潭医院矫形骨科周一新

Background  We investigated the effects of using large-diameter femoral heads in total hip prostheses on early postoperative gait restoration in patients undergoing total hip arthroplasty (THA).

Methods  We collected data for 19 primary THAs using 28-mm metal-on-polyethylene heads (conventional group) and for 12 THAs (BHR group) using metal-on-metal femoral heads with an average size of 45 mm (range, 40–49 mm). All patients had unilateral femoral head avascular necrosis. All patients underwent Harris Hip Scores evaluation and gait analysis with the IDEEA device at the same 3 time points which were before surgery and then at 1 month and again at 3 months after surgery, and the parameters measured were walking speed, stride length (SL), single limb support (SLS), cycle duration (CD), and swing power (SP). Harris Hip Scores and gait analysis parameters for both groups were compared.

Results  Intraclass comparison indicated that Harris Hip Scores, speed scores, and gate parameter measures in both groups improved significantly with the passage of time; Interclass comparison showed no significance between Harris1m postop – Harrispreop and Harris3m postop – Harrispreop in both groups. The speed in the BHR group at 1 month and at 3 months after surgery was significantly higher than that of conventional group. At 1 month after surgery, each mean for SLnormal – SLaffected, (SLSnormal – SLSaffected)/CD, and SPnormal – SPaffected in the BHR group was significantly lower than that for the conventional group. At 3 months after surgery, the differences between means for both groups for SLnormal – SLaffected, (SLSnormal – SLSaffected)/CD, and SPnormal – SPaffected were not significant, but the mean of SPnormal – SPaffected in the BHR group was significantly lower than that in the conventional group.

Conclusions  Our data show that large-diameter femoral heads in THA provide better early gait restoration than do conventional-size femoral heads.

Chin Med J 2009;122():