Denosumab showed no effect on periprosthetic bone density five years after uncemented total hip arthroplasty.

This study represents a secondary exploratory analysis of a previously published phase-2 randomized controlled trial. The population consisted of 54 non-osteoporotic patients who underwent uncemented total hip arthroplasty, with a mean follow-up of 5.6 years (range 4.3 to 7.3 years). The intervention involved two doses of denosumab, compared against a placebo control group.

At 12 months, the primary outcome assessed periprosthetic bone mineral density (pBMD). By the 5-year follow-up, the sum of pBMD in acetabular Digas zones showed an estimated mean difference of 0.042 g/cm² (95% CI -0.31 to 0.35; P = 0.8) between groups. Similarly, the sum of pBMD in femoral Gruen zones demonstrated an estimated mean difference of -0.06 g/cm² (95% CI -0.55 to 0.43; P = 0.8). No statistically significant differences were observed for patient-reported outcome measures or the incidence of heterotopic ossification.

A gradual decline in periprosthetic bone mineral density was evident over the follow-up period for both groups. Safety data, including adverse events, serious adverse events, discontinuations, and tolerability, were not reported in this analysis. The study authors noted that whether longer treatment duration or a sequential post-denosumab regimen could influence long-term bone preservation remains unknown.

The adjusted between-group difference and its 95% confidence interval indicated no statistically or clinically relevant effect of denosumab on periprosthetic bone density at five years. Given the exploratory nature of this analysis and the absence of significant findings, current evidence does not support the use of denosumab for long-term periprosthetic bone preservation in this population.