A Case-Control Comparison of Single-Stage Bilateral vs Unilateral Medial Unicompartmental Knee Arthroplasty

We aimed to compare postoperative pain, functional recovery, and patient satisfaction among patients receiving one-stage medial bilateral or medial unilateral UKA (unicompartmental knee arthroplasty). Our main hypothesis was that during the first 72 postoperative hours, patients who underwent medial bilateral UKA did not consume more analgesics than those who underwent medial unilateral UKA.

A prospective case-control study was undertaken involving 148 patients (74 one-stage medial bilateral vs 74 medial unilateral Oxford UKA). The primary outcome was evaluation of the postoperative total consumption of analgesics from 0 to 72 hours. Next, the postoperative evolution of pain scores and functional recovery were assessed. Oxford Knee Scores were assessed preoperatively at 6 and 12 months with the occurrence of clinical or radiological complications. Finally, patient satisfaction was evaluated at the final follow-up.

The cumulative sums of analgesic consumption (0-72 hours) calculated in the morphine equivalent dose were 21.61 ± 3.70 and 19.11 ± 3.12 mg in the patient and control groups, respectively (P = .30). Moreover, there were no significant differences in terms of pain scores (P = .45), functional recovery (P = .59, .34), length of stay (P = .18), Oxford Knee Scores (P = .68, .60), complications (P = .50), patient satisfaction (P = .66), or recommendations for intervention (P = .64).

Patients who undergo one-stage medial bilateral UKA do not experience more pain and do not consume more analgesics than those who undergo medial unilateral UKA. A bilateral procedure is not associated with a lower recovery or a higher rate of complications, as functional outcomes at 6 and 12 months are similar to those of unilateral management.