The cases of ten total knee arthroplasty after a proximal tibial osteotomy were compared with those of 50 primary total knee arthroplasty for osteoarthritis. The groups were matched according to age of patients, length of follow-up and type of prosthesis used. On the basis of HSS, an excellent or good result was obtained in 90% of patients who had had arthroplasty after osteotomy and in 94% of patients after a primary arthroplasty. Though some intraoperative difficulty may be encountered in a secondary prosthesis, osteotomy does not compromise a subsequent arthroplasty.