Knees for You Guide to Knee Replacement

Navigated, minimally invasive TKA offers better early results than conventional approach

By Robert Trace
September 2007

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SEOUL - Investigators reported that patients who received total knee arthroplasty via a navigated, minimally invasive approach demonstrated better functional scores at 9 months, including less blood loss and pain, compared with conventional procedure patients.

However, the researchers failed to see those differences at 1- and 2-year follow-ups.

In the prospective study, researchers compared clinical and radiological results using navigation-assisted minimally invasive (NA-MIS) and conventional techniques in bilateral total knee arthroplasty (TKA).

The research team followed 42 patients who received simultaneous bilateral TKA (84 TKAs), said Eun-Kyoo Song, MD, of Chonham National University Hwasun Hospital in Korea. They followed the patients for a minimum of 2 years and performed clinical evaluations - including range of motion (ROM), Hospital for Special Surgery (HSS) and WOMAC tests - at 3 and 6 months, and at 1 and 2 years postoperatively.

"We also compared patient subjective preferences as well as radiological [accuracies] between the two groups at 1-year postop," Song said at the 15th Triennial Congress of the Asia Pacific Orthopaedic Association (APOA).

Patients' range of motion and deformity were comparable preoperatively. The preoperative HSS scores were 68.5 in the NA-MIS group and 66.5 in the conventional group; these scores improved to 93.6 and 92.5 at 1 year postoperatively, respectively, he said.

Knees had a higher average HSS score in the NA-MIS group than in the conventional group up to 6 months postsurgery, but this difference vanished after 9 months. Likewise, "The total WOMAC scores were also better in the NA-MIS group up to 6 months out, but not after 9 months," Song added.

The ROM scores were comparable in both groups through all follow-up periods. Still, "More patients said they liked MIS better because they felt it provided better range of motion and less pain," Song said.

The radiological results were similar in both groups at 2 years, he added.

For more information:

Song E-K, Seon J-K, Park S-J, et al. Prospective comparative study between navigation-assisted minimally invasive and conventional techniques in bilateral total knee arthroplasties. F016-1. Presented at the 15th Triennial Congress of the Asia Pacific Orthopaedic Association. Sept. 9-13, 2007. Seoul.
 

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