Intra-operative analysis of the knee kinematics during total replacement. A prognostic information ?
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INTRODUCTION: We wanted to assess the possible correlation between the intra-operative kinematics of the knee and the clinical results after total knee replacement (TKR).
MATERIAL: 187 cases of TKR implanted with help of a navigation system for end-stage osteoarthritis have been prospectively analyzed.
METHODS: The navigation system can record the three-dimensional tibio-femoral movement during passive knee flexion by implanting a total knee. Two sets of records have been performed: before any intra-articular procedure and after final implantation. Kinematic data have been analyzed in a quantitative and qualitative manner. Clinical and functional results have been analyzed according to the Knee Society scoring system with a minimal follow-up of one year.
RESULTS: 101 knees had a posterior femoral translation during flexion before and after TKR. 18 knees had a paradoxical anterior femoral translation during flexion before and after TKR. 51 knees had the pre-TKR paradoxical anterior femoral translation corrected to posterior femoral translation after TKR. 14 knees had the pre-TKR posterior femoral translation modified to a paradoxical anterior femoral translation after TKR.
91 knees had a femoral external rotation during flexion before and after TKR. 34 knees had a paradoxical femoral internal rotation during flexion before and after TKR. 50 knees had the pre-TKR paradoxical femoral internal rotation corrected to a femoral external rotation after TKR. 9 knees had the pre-TKR femoral external rotation modified to a paradoxical femoral internal rotation after TKR.
There was a moderate statistical link between the reconstruction of a physiological kinematics after TKR and the quality of the clinical and functional results.
DISCUSSION: To record the knee kinematics during TKR is feasible. This information might help the surgeon choosing the optimal reconstruction compromise. However, it is not well defined how to influence final kinematics during knee replacement. The exact influence on the clinical and functional results has to be investigated more extensively.
SUMMARY: There is a statistical relationship between the intra-operative knee kinematics and the clinical and functional results.