Abstract
Background
Patient reported outcome measures (PROMs) are increasingly used to monitor recovery paths and the outcome of orthopedic procedures. One of the focus areas is endoprosthetic joint care. Unfavorable post-surgery PROM scores might indicate adverse recovery paths. As of now, an adequate definition of thresholds for recommending an adaptation of therapy does not exist. The same is true for thresholds defining treatment success.
Methods
To address this research gap, minimal clinical improvement differences and patient acceptable symptom states are estimated using anchor-based methods. Moreover, to better capture the variance in patients' recovery paths, we calculate thresholds for subgroups of patients exhibiting similar pre-operative PROM scores. For this purpose, we use patient data from two German hospitals, covering roughly 6,000 total hip and knee replacement patients treated between 2016 and 2018. Patients answered standard PROM (WOMAC, EQ-5D) and tailored patient satisfaction questionnaires prior to surgery as well as three and twelve months after surgery.
Results
Whereas we found similar threshold values for total hip and knee replacement patients at the 12 months mark, threshold values after 3 months are systematically better for hip patients than for knee patients. Moreover, we find that thresholds depend on pre-surgery PROM scores. Patients with low pre-surgery scores recover slower, patients in mid-quartiles show large score improvements, and patients in the highest quartile show only mild improvements.
Conclusions
The study shows that when defining thresholds, it should not only be discriminated by indication but also by patient's pre-surgery condition. This pre-surgery condition can best be described by pre-surgery PROM scores. Further, to implement thresholds into standard care, policy makers need to collaborate with public sickness funds and hospitals to refine thresholds based on nation-wide data.
Key messages
An adequate definition of PROM score thresholds is necessary to be able to evaluate intervention recommendations and treatment success after surgery. So far, existing research is limited. Recovery paths and therefore PROM score thresholds differ between indications and are dependent on patients’ pre-surgery condition, best described by pre-surgery PROM scores.