The long-term efficacy of unicompartmental arthroplasty of the knee.

Abstract

In a retrospective study of 48 consecutive patients (63 knees) treated by a medial unicompartmental arthroplasty for degenerative arthritis, all of the operations were performed by a single surgeon. Only Compartmental II femoral prostheses were used, coupled with either a Robert Brigham or Compartmental II tibial prosthesis that was greater than 6 mm in thickness. All components were cemented. Forty-four knees were available for follow-up examination that was performed five to 12 years postoperatively (mean, 7.4 years) by one examiner. There were 43 satisfactory results (89.6% of knees), one fair (2.1%), and four revisions (8.3%). Two knees (4.5%) had roentgenographic evidence of disease progression. Valgus alignment did not appear necessary for a satisfactory result, although most knees were within 4 degrees of neutral. Unicompartmental knee arthroplasty is indicated in properly selected patients. When properly performed, this procedure should last longer than five years.