A 2-year prospective clinical and bone density evaluation, with a subset undergoing radiostereometric analysis, using...

Total hip arthroplasty (THA) is common though the investigation of new prostheses requires a practical, step-wise introduction. This study reports the 2-year clinical results and periprosthetic bone mineral density (BMD) changes, along with a subset undergoing Radiostereometric analysis (RSA), in patients undergoing primary cemented THA using a new highly polished, double tapered, collarless femoral stem (Absolut).

Between August 2013 and December 2016, 47 patients with a mean age of 74.2 years (range 36-89) underwent 51 THAs with the Absolut. All patients underwent clinical assessment pre-surgery and at 6 weeks, 3, 12 and 24 months using the Oxford and Harris Hip Scores, as well as Dual Energy X-ray Absorptiometry (DEXA) to assess BMD within 2-4 weeks post-surgery, 12 and 24 months. RSA was undertaken in a patient subset (the first n = 30) early post-surgery (1-2 days) and 3, 12 and 24 months.

All clinical scores significantly improved (p < 0.05). RSA revealed a mean subsidence of 0.78 mm at 3 months, 1.23 mm at 12 months and 1.51 mm at 24 months. Anterior-posterior and medial-lateral translation was negligible. A significant increase (p = 0.020) in BMD was observed in Gruen zone 1, though no significant changes were observed for any other zone up until 2 years. Two patients acquired an early post-operative deep vein thrombosis that were treated accordingly and resolved, with no further complications or re-operations.

The Absolut cemented femoral stem demonstrated good outcomes, BMD changes consistent with sound prosthesis integration and patterns of post-operative micromotion observed in other successful cemented stems.