Nine studies (n=1,764) were included in the meta-analysis: four RCTs and five comparative observational studies. The sample size ranged from 30 to 1,152. Included studies were judged as good quality using the measure of quality assessment. Reviewers achieved excellent agreement in assessing study quality. The mean follow-up duration of included studies was 6.5 years (ranging from two to 13 years). There were 12 stem failures in total.
When the studies were pooled, hydroxyapatite porous coating of femoral stems compared with porous coating alone was associated with a non-significant difference in overall stem survival from aseptic loosening (RR 1.0, 95% CI: 1.00, 1.01, p=0.95) and a non-significant difference in the postoperative Harris Hip Scores (WMD 0.07, 95% CI: -0.06, 0.21, p=0.29).
There was no evidence of statistically significant heterogeneity for the outcome measures. No evidence of publication bias was found according to the visual scanning of funnel plots. Surgical complications were also reported in the review.