How do you know when it's time for a knee joint replacement? When pain is not relieved by any other means. Quite often, the patient has severe arthritis as seen on X-ray.
A 75-year old woman with a leg amputation below the knee is presented in this report. Her case is unusual because most people with an amputated leg have less arthritis in that leg. They tend to use the "good" leg more and favor the amputated side, putting less stress on the joint.
In this case the patient had severe arthritis in both knees. At first she had the knee replaced on the nonamputated side. When she could no longer move the knee on the amputated side, that knee joint was replaced. A joint replacement on an amputated leg has more than the usual risks. For this woman, decreased blood flow led to the amputation in the first place. A joint replacement increases her risk of a second amputation further up the leg (mid-thigh).
Physical therapy started the day after surgery. She went home on the eighth day, when she could use a wheelchair without help. Eight months later she was pain-free and could walk without help up to 100 yards (the length of a football field).
The doctors on this case report that the joint replacement operation was modified a little for a leg amputation below the knee. They show a good result with joint replacement first on the nonamputated side. This way the patient could put weight on the nonamputated side when the time came time to replace the second knee.
The authors conclude that a knee joint replacement is possible for someone with severe arthritis in the knee of an amputated leg.
John R. Crawford, BSc, FRCS, and Nigel Coleman, FRCS. Total Knee Arthroplasty in a Below-Knee Amputee: A Case Report. In The Journal of Arthroplasty. August 2003. Vol. 18. No. 5. Pp. 662-665.'