Impact of preoperative chronic pain diagnosis on unicompartmental knee arthroplasty surgery: Analysis of healthcare utilization and patient reported outcomes.

BACKGROUND

This study investigates (i) clinically relevant improvements in patient-reported outcome measures (PROMs), (ii) satisfaction rates at one-year post-unicompartmental knee arthroplasty (UKA), and (iii) patterns of healthcare utilization (HCU) in patients with and without preoperative chronic pain.

METHODS

A total of 1275 patients who underwent primary elective unilateral UKAs at a large tertiary academic center in the United States between 2016 and 2022 were included in the cohort. Electronic medical record (EMR) was used to identify a preoperative diagnosis of chronic pain using ICD coding. The included PROMs were the KOOS Pain, PS, JR. Clinically relevant improvements were evaluated using established minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) threshold achievement.

RESULTS

There were 234 (18.4 %) with a chronic pain diagnosis before their UKA. Chronic pain was not associated with failure to reach MCID improvement in any of the KOOS subscales. However, it was associated with failure to reach PASS in KOOS Pain, but not KOOS PS or KOOS JR. Chronic pain was not associated with dissatisfaction at 1-year after UKA (p = 0.112). There was no difference in discharge to home/home healthcare between chronic pain and non-chronic pain patients (p = 0.706). Similarly, there was no statistically significant difference in 90-day readmissions between the two groups (p = 0.38). After adjusting for possible confounding variables, patients with a preoperative chronic pain diagnosis were not associated with a prolonged LOS (p = 0.298).

CONCLUSION

Chronic pain patients reported similar 1-year satisfaction and self-perceived improvement in knee function and pain relief to their non-chronic pain counterparts. Surgeons may use these results to reassure and set optimistic expectations in these patients.