Comparison of Bone Remodeling Between Collum Femoris-Preserving Stems and Ribbed Stems in 1-Stage Bilateral Total Hip Arthroplasty

BACKGROUND: This study examined a cohort of patients who underwent bilateral THAs. CFP prostheses and ribbed prostheses were each used on both sides. We assessed the midterm clinical, radiological, and bone remodeling outcomes around prosthesis of these patients. MATERIAL/METHODS: From January 2009 to January 2013, 53 patients were enrolled in our study. We clinically evaluated all patients by recording Harris hip and Oxford hip scores. Some radiological indicators of the femoral prosthesis position were measured. Periprosthetic bone remodeling was assessed via bone mineral density (BMD) measurements. RESULTS: The mean preoperative HHS of the CFP group and ribbed group were no significantly different (P=0.570). The neck-shaft angle in the ribbed group was significantly greater than in the CFP group (P<0.001). The CFP group had a greater offset (P<0.001). There was no significant difference in leg-length discrepancy (P=0.727) or Engh score between the 2 groups at the last follow-up (P=0.858). The preoperative BMD was increased at the last follow-up in Gruen zones 3 and 5 (P<0.05) and decreased in Gruen zones 1 and 7 (P<0.05) on the CFP side. BMD was increased in Gruen zone 4 (P=0.007) on the ribbed side. Pearson correlations and rate of complications were not significantly different. CONCLUSIONS: Both the CFP and ribbed stem significantly improved the preoperative HHSs and OHSs. The bone remodeling of the CFP stem was more concentrated in the middle and distal regions of the prosthesis, while that of the ribbed stem was more concentrated in the proximal portion of the prosthesis.