Outcome of unicompartmental knee arthroplasty in patients receiving worker's compensation.

Nineteen patients with a worker's compensation board (WCB) claim treated by unicompartmental knee arthroplasty for medial compartment osteoarthritis were compared to 20 patients who had no WCB claim. In WCB patients, the mean Knee Society Score (KSS) improved from 47.4 to 76.9; the mean Knee Society function score, from 43.8 to 75; and the mean Knee society pain score, from 6.9 to 29.4. In non-WCB patients, the mean KSS improved from 43.3 to 90.7; the mean Knee Society function score, from 44.7 to 90; and the mean Knee Society pain score, from 3.6 to 41.7. The difference in improvement of KSS between the two groups was significant (P = .008). The postoperative KSS in the non-WCB patients was significantly higher than that of the WCB group (P = .007). There was no difference between the incidences of conversion to total knee arthroplasty.