Navigation Prediction for Balancing of Soft Tissue and Flexion-extension Gap in Primary TKA

This title focuses on such areas as: joint replacement and hip, knee and lower extremity.

This study demonstrates navigation-assisted gap balancing technique for primary TKA and evaluates the effectiveness of navigation for soft tissue balancing and flexion-extension gaps.

Mid-term clinical results are included. The following are the materials and methods of this title.

The authors evaluated 112 osteoarthritic knees (88 patients) with varus deformity treated by TKA using gap technique with a navigation system.

The mean follow-up was 52.8 months (range, 48-58 months).

After registration, the mechanical axis was restored to neutral (+/-2) at full extension with medial release.

Tibial cutting was performed under navigation control.

Flexion and extension gaps were measured using a tensioning device and distraction forces (50 lb/inch) before femoral cutting.

The differences between flexion and extension gap were classified into two groups: the balanced group was defined as having a difference within 3 mm; the difference in the imbalanced group was 3 mm or greater.

Sixty-seven (59.8 per cent) knees were classified as balanced and 45 (40.2 per cent) as imbalanced. With the prediction of the above flexion-extension gap difference, the anteroposterior and distal cutting of the femur was adjusted for balancing, and the flexion-extension gap was re-measured before prosthesis insertion.