Hospital volume has been suggested to be one of the best indicators of adverse orthopedic events in patients undergoing THR surgery. We therefore evaluated the effect of hospital volume on the length of stay, re-admissions, and complications of THR at the population level in Finland.

30,266 THRs performed for primary osteoarthritis were identified from the Hospital Discharge Register. Hospitals were classified into 4 groups according to the number of THRs performed on an annual basis over the whole study period: 1–50 (group 1), 51–150 (group 2), 151–300 (group 3), and > 300 (group 4).

In 2005, the length of the period of surgical treatment was 5.5 days in group 4 and 6.8 days in group 1 (the reference group). During the whole study period (1998–2005), the length of surgical treatment period was shorter in group 4 than in group 1 (p < 0.001). The odds ratio for dislocations (0.7, 95% CI: 0.6–0.9) was lower in group 3 than in group 1.

Hip replacements performed in high-volume hospitals reduce costs by shortening the length of stay, and they may reduce the dislocation rate.