Bone restoration after revision hip arthroplasty with femoral bone defects using extensively porous-coated stems with cortical strut allografts

BACKGROUND: Stress shielding and bone loss of the femur are of great concern after revision total hip arthroplasty (THA) with extensively porous-coated stems, especially in a femur with already bone loss. The femoral bone remodeling patterns after revision THA with femoral bone defects using extensively porous-coated stems with cortical strut allografts remain unclear. METHODS: We retrospectively reviewed 47 patients who underwent revision THA using extensively porous-coated stems combined with cortical strut allografts and 75 patients without allografts. The minimum follow-up was 2 years. Femoral bone remodeling signs, including stress shielding, bone restoration in bone defect area, distal cortical hypertrophy, and femoral width, were compared between patients with and without cortical strut allografts. Clinical outcomes were also compared between two groups. RESULTS: Patients with cortical strut allografts showed less severe stress shielding (P = 0.01) than patients without allografts. Patients with allografts had more osseous restoration in bone defect area than patients without allografts (63.8% vs 30.7%, P < 0.001). Femoral width was significantly higher in femur with allografts than in femur without allografts at the immediate postoperative stage and latest follow-up (both P < 0.001). The hip function score, re-revision rate, and complications were comparable between two groups. CONCLUSION: The application of cortical strut allografts can decrease the severity of stress shielding, augment osseous restoration in bone defect area and improve femoral bone stock after revision THA using extensively porous-coated stems.