The fate of sagittal alignment in tapered uncemented femoral components in total hip arthroplasty: 889 hips followed for a minimum of 10 years

Aseptic loosening is rare after primary total hip arthroplasty (THA) with mostly uncemented tapered stems; however, different factors can modify the results. We question whether 3 different current femoral components and/or the surgical technique affect the clinical and radiological outcome after a minimum follow-up of 10 years.

889 uncemented tapered stems implanted from 1999 to 2007 were evaluated for a minimum follow-up of 10 years. Group 1 (273 hips) shared a conical shape and a porous-coated surface, group 2 (286 hips) a conical splined shape and group 3 (330 hips) a rectangular grit-blasted stem. Groups 1 and 2 were implanted through a posterolateral approach and group 3 using an anterolateral approach. Clinical outcomes and anteroposterior and sagittal radiographic analyses were compared.

No thigh pain was reported in unrevised patients. Mean Harris Hip score was lower for patients in group 3 for pain and function at all intervals. 14-year implant survival for aseptic loosening was 98.2% (95% confidence interval [CI] 96.2–100) in group 3. No revision for aseptic loosening was found with the other designs. A stem position outside neutral limits in the sagittal alignment (p = 0.001, hazard ratio: 6.17, 95% CI, 2.05–18.61) was associated with aseptic loosening in group 3.

Most current uncemented straight tapered femoral components can provide adequate bone fixation in primary THA after 10 years. Conical stems inserted through a posterolateral approach are more reliable than rectangular ones inserted through an anterolateral approach.