Observational study of operating room times for knee and hip replacement surgery at nine U.S. community hospitals.

Knee (N = 185) and hip (N = 140) replacement cases were studied at nine community hospitals in the midwestern United States to determine whether certain management interventions could decrease case durations and reduce labor costs. Substantive (10 min) reductions in operating room (OR) time per case were not associated with: 1) increases in OR staffing, such as the addition of a surgical assistant; 2) complete elimination of all delays; or 3) increases in anesthesiologists' presence in the ORs. Substantive (10 min) increases in OR time per case were not associated with: 1) reductions in anesthesiologists' presence in the ORs or 2) changes in case scheduling to run fewer ORs, with some cases starting later in the day. Even if these factors had been associated with differences in OR time per case, any changes resulting from management interventions would still not have reduced labor costs. At these hospitals, OR nursing and anesthesia labor costs were fixed costs, because the OR workload averaged only 5.6 hr of cases per day.