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Results of Computer-Assisted Knee Replacement

In this study, the results for two groups of knee replacement surgery were compared. Patients in both groups were operated on using the smallest incision possible. The first group had a unicompartmental knee arthroplasty UKA). Just the medial side (closest to the other knee) was replaced.

The second group had a total knee replacement (TKR). The surgeon used a computer-assisted minimally invasive surgery (CA-TKR). The incision for the CA-TKR group was slightly longer than for the UKA group. But it was less than the traditional open-incision method for TKR.

Patients in both groups were matched by age, severity of arthritis, gender, and range of motion (as recorded before the operation). Results were measured by comparing a wide range of variables. These included motion, function, and weight-bearing status. Surgical time, length of hospital stay, and costs were also reviewed.

The UKA group had a higher functional score on the Knee Society test given. More patients in the UKA group had full range of motion (120 degrees of knee flexion) compared with the CA-TKR group. Three times as many patients in the UKA group could walk more than one kilometer (0.62 miles).

Hospital stay, total cost, and complications were higher in the CA-TKA group. The authors conclude that computer-assisted technology allows more accurate implant placement. Even so, the overall results aren't as good as with the UKA. Added cost for more expensive implants, technology, and longer time in the hospital with CA-TKA point to the UKA as a better choice. This is especially true for older patients with medial compartment arthritis.

References: N. Confalonieri, MD, et al. Navigated Shorter Incision or Smaller Implant in Knee Arthritis? In Clinical Orthopaedics and Related Research. October 2007. No. 463. Pp. 63-67.

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