OBJECTIVES: Reducing variations in outcomes for total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures will be critical for providing high-value care. While research has found that hospital outcomes are better for patients treated by high-volume providers, most research has examined annual volumes, despite the fact that volumes may fluctuate substantially by month. The objective was to evaluate the association of monthly surgeon and hospital volume on hospital outcomes, including the presence of complications, readmission within 30 days, hospital length of stay and hospital cost of care.

METHODS: Patient discharge-level data were obtained from the Vizient Clinical Database for 264 academic medical centers and their affiliated hospitals. The sample included all discharges with a THA or TKA procedure between June 2013 and May 2016. Surgeon and hospital volumes were assessed on a monthly basis and classified into monthly volume quartiles (. A composite volume variable was created for surgeon and hospital volume quartiles (high surgeon-high hospital, high surgeon-low hospital, low surgeon-high hospital, and low surgeon-low hospital volume). Multivariable regression models were fit to test the association between each hospital outcome with volume, controlling for patient and hospital characteristics.

RESULTS: Fifty-nine percent of 146,336 THA patients and 50% of the 224,652 TKA patients were treated by a high surgeon-high hospital volume provider. Patients with high surgeon-high hospital volume providers were less likely to be readmitted within 30 days, have shorter LOS and lower hospital costs than patients treated by lower volume providers for both THA and TKA procedures. Outcomes were the worst for patients treated by low surgeon-low hospital volume providers

CONCLUSIONS: Maintaining consistently high surgeon and hospital volumes may be a strategy for improving the value of care for THA and TKA procedures.