The effect of intramedullary bone plug on femoral stem migration of hydroxyapatite-coated hip arthroplasty.

This study investigated the effect of intramedullary corticocancellous bone plug on the fixation and stability of hydroxyapatite-coated femoral stems in total hip arthroplasty (THA). Intramedullary corticocancellous bone plug was used in 30 patients with hydroxyapatite-coated femoral stems (group A) and a consecutive series of 30 patients with hypdroxyapatite-coated stems without bone plug served as the control group (group B). Patients underwent clinical and radiographic follow-up for at least 2 years. The addition of corticocancellous bone plug to the hydroxyapatite-coated stem significantly improved clinical and radiographic results. The mean Harris Hip Score at 3 and 6 months postoperatively was 92 and 94 in group A, and 84 and 87 points in group B (P<.004 and P<.001, respectively). There was no significant difference between groups at 1 year postoperatively and thereafter. The predominant cause for the difference was the thigh pain score, which was reduced at both 3 and 6 months in group A compared to group B (P<.01 and P<.05, respectively). There also were statistical differences between the two groups regarding radiographic signs. The evidence of endosteal bone formation in group A patients was superior at 3 and 6 months (P<.001 and P<.01, respectively). The appearance of a radiolucent line was significant in group B patients at 3 and 6 months (P<.001). Femoral stem migration of 3 mm was noted in three group B patients versus no group A patients (P<.05). These short-term clinical and radiographic results suggest corticocancellous bone plug can provide early pain relief and durable implant fixation, but long-term follow-up should be considered.