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Something Fishy in the Knee after UKA

Unicompartmental knee arthroplasty (UKA) is the replacement of just one side of a knee joint. It's used most often for osteoarthritic changes on one side of the femur. The femur is the thighbone, which has two rounded, knuckle-like projections where it meets the knee. These bumps are called condyles. The condyles form the top half of the knee joint. A UKA
replaces one of the condyles.

These authors report the case of a 66-year-old woman who had a lateral UKA. In a lateral UKA, the outer condyle of the knee joint is replaced. Everything went well for about 16 months. Then she started having pain along the outside edge of her knee. It was persistent, especially when she bent her knee. The doctors thought there might be a loose piece of cement or plastic in the joint.

An arthroscopic exam was done. In this procedure, the doctors insert a long, thin instrument with a tiny camera into the joint. The camera projects onto a TV screen so the doctor can see the inside of the knee. In this case, the doctors could see that her meniscus (cartilage) was getting caught between two parts of the implant.

A special hook was used to free the meniscus. It was then shaved down so it couldn't get caught again. The patient was pain-free right after the operation. By the end of two weeks she had almost all her motion back. Within six months she had regained her knee strength as well. The authors conclude that arthroscopic exams can be done after a UKA. Care must be taken to avoid infection, but the operation is safe and simple.

References: Mian Munawar Shah, FRCS, and Shamael Ahmed Yunus, FRCS. Bucket-Handle Tear in Retained Meniscus after Unicompartmental Knee Arthroplasty: A Case Report. In Arthroplasty. August 2003. Vol. 18. No. 5. Pp. E51-E53.

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