Time-Dependent Prediction Models for Individual Prognosis of Chronic Postsurgical Pain following Knee Replacement Based on an Extensive Multivariable Data Set.

(1) Background: Clinically useful prediction models for chronic postsurgical pain (CPSP) in knee replacement (TKA) are lacking. (2) Methods: In our prospective, multicenter study, a wide-ranging set of 91 variables was collected from 933 TKA patients at eight time points up to one year after surgery. Based on this extensive data pool, simple and complex prediction models were calculated for the preoperative time point and for 6 months after surgery, using least absolute shrinkage and selection operator (LASSO) 1se and LASSO min, respectively. (3) Results: Using preoperative data only, LASSO 1se selected age, the Revised Life Orientation Test on pessimism, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-subscore pain and the Timed "Up and Go" Test for prediction, resulting in an area under the curve (AUC) of 0.617 and a Brier score of 0.201, expressing low predictive power only. Using data up to 6 months after surgery, LASSO 1se included preoperative Patient Health Questionnaire-4, Knee Injury and Osteoarthritis Outcome Score (KOOS)-subscore pain (pain) 3 months after surgery (month), WOMAC pain 3 and 6 months, KOOS subscore symptoms 6 months, KOOS subscore sport 6 months and KOOS subscore Quality of Life 6 months. This improved the predictive power to an intermediate one (AUC 0.755, Brier score 0.168). More complex models computed using LASSO min did little to further improve the strength of prediction. (4) Conclusions: Even using multiple variables and complex calculation methods, the possibility of individual prediction of CPSP after TKA remains limited.

[Discharge readiness versus discharge-Results of the PROMISE study]. / Entlassbarkeit versus Entlassung ­ Ergebnisse der PROMISE-Studie.

BACKGROUND: In the context of optimized treatment processes for knee and hip replacements, lengths of stay are given for Germany that clearly exceed the internationally published ones. In this context, the present analysis of data from the PROMISE study deals with the relationship between discharge readiness and discharge. METHODS: In the PROMISE study, a jointly developed, optimized standard of care was established in three hospitals of different levels of care and realized for a typical, largely unselected cohort of patients. Among others, data were collected on achievement of discharge criteria (DC) and actual discharge. Univariate comparisons were performed by chi-square tests or the Mann-Whitney­U tests. RESULTS: A total of 1782 patients were included, of whom a mean of 85.3% achieved all previously defined DCs at a mean of 2.4 (median 2) days postoperatively. Discharge for this group occurred after a mean of 5.4 (median 5) days. 14.7% of the participants did not achieve at least one DC. This group was discharged after a mean of 6.5 (median 6) days. Significant differences in outcomes were observed for different subgroups. CONCLUSION: The so-called DCs are used as relative criteria. Achievement generally does not result in timely discharge. If this were to happen, internationally established lengths of stay would also be a reality in Germany. What actually determines discharge from inpatient treatment remains open. A variety of medical, organizational, structural and financial factors could be of importance.