Fast track hip and knee arthroplasty: impact of different hospital care levels.

Objectives: Total knee and hip replacements are among the most common surgical procedures. Optimization of the treatment process is of great relevance and requires verification of effectiveness in different settings. The PROMISE study was carried out to achieve this. Methods: An optimized treatment process was implemented in 3 German hospitals with different levels of care. A total of 1,887 patients were included. The WOMAC Score was established as the outcome parameter at 3, 6 and 12 months after surgery. A mixed model for repeated measurements was used to estimate site-specific effects as well as the limits of the corresponding confidence intervals. To demonstrate homogeneous results across all sites, these outcomes needed to fall within a range defined by the overall effect ± the minimally clinically important difference (MCID), using a 95 % confidence interval. Results: All site-specific results ranged from (points [CI-limits]) -29.2 [-29.7; -28.7] to -24.4 [-24.5; -24.3] and were therefore within the range defined by the overall treatment effect and the MCID (25.4 ± 10). Conclusions: We could demonstrate homogeneous site-specific effects of the optimized process in the three most different settings of the German healthcare system. Therefore, an essential prerequisite for a system-wide rollout has been met.