Prioritization of patients on scheduled waiting lists: validation of a scoring system for hip and knee arthroplasty

The hip and knee replacement priority criteria tool (HKPT) is 1 of 5 tools developed by the Western Canada Waiting List Project for setting priorities among patients awaiting elective procedures. We set out to assess the validity of the HKPT priority criteria score (PCS) and map the maximum acceptable waiting times (MAWTs) for patients to levels of urgency.

Two studies were used to assess convergent and discriminant validity. In study 1, consecutive patients on a waiting list for hip or knee arthroplasty were assessed by orthopedic surgeons from the 4 provinces in Western Canada, using the HKPT and data on patient age, gender, joint site, type of surgery (primary or revision), 2 measures of surgeon-rated patient urgency, and diagnosis. In study 2, 6 patients were videotaped during a consultation interview with the surgeon and were assessed by a group of experts. We measured function with the PCS and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

In study 1, we assessed 394 patients, and in study 2, 19 raters assessed the 6 patients. Correlations between the PCS and other measures of physician-rated urgency were strong, ranging from 0.78 to 0.89. For a subgroup of 60 patients, correlation between the PCS and function as measured with the WOMAC was 0.48, and correlation was greater (0.45-0.56) between items measuring similar constructs (e.g., pain at rest) than those measuring different constructs (0.21-0.40). In study 2, median MAWTs ranged from 4 to 24 weeks for 5 levels of urgency based on PCS percentiles.

Results from this study support the validity of the PCS as a measure of surgeon-rated urgency for hip or knee arthroplasty. Evaluative studies are needed to assess the validity and acceptability of the tools and the establishment of MAWTs in clinical practice.