Disease Progression After Unicompartmental Arthroplasty: Add a Compartment or Revise to Total Knee Arthroplasty?

BACKGROUND

Five percent to 7% of unicompartmental knee arthroplasties (UKA) require revision for disease progression in untreated compartment(s), most commonly to total knee arthroplasty (TKA). TKA requires removal of bone and usually the anterior cruciate ligament. Preserving the UKA and converting to a bicompartmental arthroplasty (BCA) by performing a second UKA is an alternative.

METHODS

The results of 73 UKA-BCA patients were compared to 75 patients treated by UKA-TKA revision. Knee Society, Knee Osteoarthritis Outcome Score Joint Replacement, and patient satisfaction scores were collected by a blinded therapist. Patients were asked about their implant preference and recovery. Twenty-two UKA-BCA revision patients had a UKA (6) or TKA (16) in the contralateral knee; thus, a direct comparison of UKA-BCA to both UKA and TKA was possible.

RESULTS

Of the UKA-BCA patients, 69 (94%) had excellent or good, 2 (3%) fair, and 2 (3%) poor outcomes with 1 patient requiring revision to TKA. Of patients with a TKA in the contralateral knee, 13 (81%) preferred the UKA-BCA replacement and 3 (19%) preferred the TKA. All patients said the UKA-BCA revision recovery was similar or easier than their initial UKA. Of UKA-TKA revisions, 59 (79%) had excellent or good, 9 (12%) fair, and 7 (9%) poor outcomes. There was 1 wound infection and 1 re-revision in the UKA-BCA group and 1 wound infection and 3 re-revisions in the UKA-TKA group. The Knee Osteoarthritis Outcome Score Joint Replacement and Knee Society Scores were better for UKA-BCA compared to UKA-TKA.

CONCLUSION

UKA-BCA is a successful treatment for disease progression following UKA.