[Is it possible to calculate minimum provider volumes for total knee replacement using routine data? Results of a threshold value analysis of German quality assurance data for inpatient treatment].

AIM OF THE STUDY: The aim of this study was to calculate, for the first time, minimum provider volumes in total knee replacement using routine German data.
MATERIALS AND METHODS: In patients with primary total knee replacement (TKR), the relationship between hospital volume per year and risk of "insufficient mobility" (primary quality indicator) and "wound infection" (secondary quality indicator) was calculated by means of logistic regression models.
RESULTS: For both indicators, a statistically significant relationship between hospital volume and outcome could be demonstrated. Other risk factors such as age and ASA status also had a significant influence, but did not appear as important confounders. The risk for the secondary quality indicator "infection" decreased constantly with increasing hospital volume, thus the curve was very flat. This supports the hypothesis that high volume hospitals have a higher quality level than low volume hospitals. A threshold value could be calculated. However, the explanation value for hospital volume was too low to derive a threshold level that clearly discriminates between good and bad quality of care. The relationship between the primary quality indicator "insufficient mobility" and hospital volume unexpectedly showed a U-shaped distribution. This questions the concept of a minimum provider volume regulation for primary total knee replacement for the quality indicator "insufficient mobility". Therefore, in this case no quantitative threshold values were calculated.
CONCLUSION: This analysis supports the hypothesis of a volume-outcome relationship in primary total knee replacement. However, a minimum provider volume that clearly discriminates between good and bad quality of care could not be calculated on the basis of these German quality assurance data.