BackgroundOsteoarthritis (OA) is one of the primary causes of pain and disability worldwide leading to patients having some of the worst health-related quality of life (QOL). The purpose of our study was to investigate the progression of the generic and disease-specific QOL of osteoarthritic patients going through total hip or knee replacement surgery and the factors that might alter the effect of surgery on QOL.MethodsA longitudinal study was performed based on data collected from 120 OA patients who filled in the short version of the WHO’s generic measure of quality of life (WHOQOL-BREF) and the disease-specific Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) before and after surgery.ResultsDomains related to physical health status showed relatively lower scores in patients before surgery. Patients reported a significant increase of QOL after surgery in the WHOQOL-BREF physical domain, especially if they were from the younger group (< 65 years, p = 0.022) or had a manual job (p = 0.008). Disease-specific QOL outcome results indicate that overall patients gained significantly better QOL in all domains of the WOMAC score. Patients with hip OA seemed to have the most benefit of their operation as they reported better outcome in WOMAC pain (p = 0.019), stiffness (p = 0.010), physical function domains (p = 0.011) and total score (p = 0.007) compared to knee OA patients.ConclusionThere was a statistically significant improvement in all domains concerning physical functions in the study population. Patients also reported significant improvement in the social relationship domain, which indicates that OA itself as well as its management might have a profound effect on patients’ life beyond the reduction of their pain.