As total knee arthroplasties (TKA) have become the gold standard procedure for severe gonarthrosis, greater interest in postperative tibiofemoral instability has developed.

Emphasizing the correlation between evaluation of symptoms and findings, offers an opportunity to elucidate the specifics of the instability.

Mandatory is the joint gap measurement during surgery to assess the effect of specific cuts or releases of the anatomic portion of the joint gap.

By performing navigation-assisted total knee arthroplasties, we are capable of measuring the joint gap in a highly reliable way.

During the ligament balancing in navigation-assisted TKA, we performed a data collection of the joint gap in 0–30 and 90 of flexion in 100 patients.

The measurements were repeated after 10 and 20 minutes in extension.

The result offers us an opportunity to assess the interesting effect of ligament-stress relaxation in TKA and to gain more insights in the further release-necessity and choice of insert during the TKA procedure.

Aims: We studied the outcome of a progressive correction of the rotation malalignment syndrome with combined supracondylar and proximal tibial osteotomy. We evaluated the associated anterior knee pain in most patients due to patellar maltracking. Methods: Between 1991 and 2002, 56 combined femoral and tibial osteotomies were performed in 37 patients (mean age 18 years). Ilizarov method was used for correction of the idiopathic anteversion with combined tibial external rotation. The þxator was kept in place for an average of 4.4 months and mean follow up was 3 years. Results: In more than 90% of the patients with preoperative anterior knee pain, the symptoms diminished or disappeared. All alignments were corrected adequately. A temporary neuropraxia of the peroneal nerve was seen with acute derotation of the tibia. This technique was abandoned. Four patients were not satisþed for cosmetic reasons, due to the multiple scars from the pins especially on the upper thigh. Postoperative problems were uncommon. There was one undisplaced femoral fracture after removal of the frame and one overcorrection was seen, that could be treated with a new osteotomy with progressive external derotation. Conclusions: The progressive derotation technique using the Ilizarov method allows a reliable correction of a rotational malalignment syndrome with a concomitant improvement of anterior knee pain