This observational study compared the outcomes of 271 cases of hip osteoarthritis receiving primary total hip replacement (patients 65 years of age and older) from numerous surgeons in 12 Baltimore region hospitals from 1991-1993. The independent variables studied were: (a) totally non-cemented prostheses (non-cemented femoral component, non-cemented acetabular component) versus hybrid prostheses (cemented femoral component, non-cemented acetabular component), and (b) lateral or anterolateral surgical approach versus posterior surgical approach. Outcomes included complications during the initial hospitalization, hospital length of stay, hospital cost, readmission, and reported and/or observed physical, instrumental, neuromuscular and affective functioning and pain at 2, 6, and 12 months post surgery. Results indicated that, while the totally non-cemented prosthesis was more costly, there were no statistically significant differences in clinical or functional outcomes between the non-cemented and the hybrid prostheses up to 12 months post surgery. Also, while the posterior surgical approach was associated with a non-statistically significant higher rate of dislocation, overall, there was improved function and reduced pain in the first 12 months post-surgery associated with this approach.