Is hydroxyapatite coating necessary to improve survivorship of porous-coated titanium femoral stem?

We compared the clinical and radiologic results in 55 patients (110 hips) associated with proximally porous-coated titanium stems that were identical in geometry but differed with regard to proximal surface treatment (with or without hydroxyapatite coating). The mean age at the time of the operation was 46.3 years (27-63 years), and mean length of follow-up was 15.6 years (15-16 years). The mean Harris hip score in both groups improved from 39 points and 41 points, respectively, to 93 and 91 points, respectively, at the last follow-up. After 16 years, the cumulative survival for the stem was 100% in both groups and for the cup was 89% in both groups. After long-term follow-up, hydroxyapatite coating on the porous surfaces did not improve or diminish the results of total hip arthroplasty.