Unicompartmental knee arthroplasty has been used to treat elderly,
low-demand patients, but the literature is sparse regarding the use of this
procedure for younger, active patients. The purpose of the present
retrospective study was to evaluate the results of unicompartmental knee
arthroplasty in younger, more active patients.
Forty-one patients underwent forty-six consecutive unicompartmental knee
arthroplasties with use of the Miller-Galante system between 1988 and 1996.
All of the patients were sixty years of age or younger and all were physically
active. The Hospital for Special Surgery knee score and the University of
California at Los Angeles activity assessment were used to rate the function
and to determine the activity level of each patient, respectively. Serial
radiographs were used to evaluate the status of prosthetic fixation,
femorotibial alignment, and the progression of arthrosis in the unreplaced
compartment. Long-term survivorship was calculated with use of Kaplan-Meier
The mean duration of follow-up was eleven years. Of the forty-five knees
that were available for follow-up, three had been revised. The Hospital for
Special Surgery score was excellent for thirty-nine (93%) of the remaining
forty-two knees and good for three. The University of California at Los
Angeles activity assessment score was 6.6 ± 1.4 for the knees in which
the original prosthesis had been retained and 7.3 ± 1.5 for those in
which it had been revised. Two asymptomatic patients had revision of a modular
tibial component because of substantial radiographic evidence of polyethylene
wear; one of these patients had exchange of the polyethylene insert and the
tibial tray, and the other had exchange of the polyethylene insert only. A
third patient underwent revision total knee arthroplasty because of continuing
knee pain and a progressive tibial radiolucent line that was >2 mm in
width. The average postoperative femorotibial alignment was 5° of valgus.
Nine knees had progression of arthritis in the unresurfaced compartment; none
of these knees were revised, and none of the patients had deterioration in the
Hospital for Special Surgery score. Kaplan-Meier analysis demonstrated an
eleven-year survivorship of 92%.
At an average duration of follow-up of eleven years, unicompartmental knee
arthroplasty was associated with pain relief and excellent function in a
cohort of patients who had been sixty years of age or younger and active at
the time of surgery.