Influence of Implant Characteristics on Functional Outcomes After Total Hip Arthroplasty: An Ambispective Observational Study

Abstract Background Implant characteristics, such as fixation method, femoral head size, and bearing surface, may influence outcomes after total hip arthroplasty (THA). Data from India regarding their impact on patient-reported outcome measures (PROMs) are limited. Methods An ambispective observational study was conducted on 57 patients (72 hips) who underwent primary THA. Patients were subgrouped by fixation type (cemented vs. uncemented), head size (28 mm vs. 32 mm), and bearing surface (metal-on-polyethylene vs. ceramic-on-polyethylene surface). Outcomes were assessed using the Modified Harris Hip Score (mHHS), Oxford Hip Score (OHS), and Forgotten Joint Score (FJS-12) preoperatively and at serial follow-ups up to one year. Results Uncemented stems showed significantly higher PROMs at one year compared with cemented stems (mHHS: 89.1 vs. 82.2, p < 0.001; OHS: 45.2 vs. 42.7, p = 0.004; FJS-12:82.4 vs. 74.2, p = 0.002). Femoral heads measuring 32 mm were associated with superior FJS-12 scores compared with 28 mm heads (83.1 vs. 76.5, p = 0.031), although differences in mHHS and OHS were not significant. The bearing surface type had no significant impact on the outcomes. The overall complication rate was 16.7%, with dislocations more frequent in smaller head sizes. Conclusion Implant-related factors significantly affect functional outcomes after THA. Uncemented fixation and larger femoral heads were associated with improved PROMs, whereas the bearing surface type had no effect at one year. PROM-based evaluations can guide implant selection and should be incorporated into future multicenter studies in the Indian population.