The outcome of failed knee arthrodesis following total knee arthroplasty.

After failure of total knee arthroplasty, arthrodesis was attempted in 120 cases, and unsuccessful in 25 (21%). Failure of arthrodesis was defined as nonunion persisting one year after arthrodesis or reoperation to obtain union. The number of attempts at arthrodesis ranged from one to four. The most frequent reasons for reoperation were persistent pain and instability. Most failures were caused by poor apposition owing to bone loss. Union was obtained in ten knees (average follow-up period, 44.5 months), but not in 11 (average, 35.3 months).