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Positioning Unicompartmental Knee Arthroplasty Implant Using Minimally Invasive Surgery

There are two ways to implant a knee replacement. The standard method is with an open incision. More recently, computer-aided systems have made it possible to do minimally invasive surgery (MIS). With MIS, a very small incision is made.

There are concerns about the accuracy of implant positioning using the MIS method. In this study, two groups of patients are compared. All patients received a unicompartmental knee arthroplasty (UKA). This is the replacement of just one side of the joint.

One group had the open incision surgery. The second group had the MIS. All surgeries were done by the same experienced knee reconstruction surgeon. X-rays were used to measure angles and orientation of the UKA implant. The results showed no difference in implant accuracy between the two groups. Operating time and rate of complications were also similar.

Long-term studies are still needed to look for any links between limb alignment and long-term survival of the implant. It's possible that poor implant position will alter limb alignment and result in faster wear and tear.

Some studies have already shown reduced function in patients with malalignment. More studies are needed to compare open versus MIS UKA. Factors to compare include rates of recovery, accuracy of implant position, function, and cost.

References: Jean-Yves Jenny, MD, et al. The Rationale for Navigated Minimally Invasive Unicompartmental Knee Replacement. In Clinical Orthopaedics and Related Research. October 2007. No. 463. Pp. 58-62.

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