Article
Intra-operative analysis of the kinematic behavior of a total knee replacement by a navigation system. Initial experience and further development
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Authors
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Jean-Yves Jenny
- Hôpitaux Universitaires de Strasbourg, CCOM, Illkirch, France
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Yann Diesinger
- University Hospital Strasbourg, CCOM, Illkirch, France
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Franz-Peter Firmbach
- University Hospital Strasbourg, CCOM, Illkirch, France
| Published: | October 5, 2015 |
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Outline
Text
Objectives: An intra-operative analysis of the knee kinematics during TKA may allow improving the reconstruction by choosing the most appropriate component adaptation and ligament tension. We developed a specific software derived from a clinically used navigation system to allow in vivo registration of the knee kinematics before and after total knee replacement. We wanted to test for the feasibility of the intra-operative registration of the knee kinematics during standard, navigated TKA.
Methods: The standard navigation software has been modified to allow the intra-operative registration of the knee kinematic. Kinematic registration was performed twice during an usual procedure of navigated TKA:
- 1.
- Before any bone resection or ligamentous balancing;
- 2.
- After fixation of the final implants.
200 cases of total knee replacement have been analyzed. Post-operative kinematic was classified as following:
- 3.
- Occurrence of a normal femoral roll-back during knee flexion, no roll-back or paradoxical femoral roll-forward.
- 4.
- Occurrence of a normal tibial internal rotation during knee flexion, no tibial rotation or paradoxical tibial external rotation.
All patients were followed up for a minimal period of 12 months, and reevaluated at the latest follow-up visit for clinical and functional results with completion of the Knee Society Scores. The influence of the post-implantation kinematic on the Knee Society Scores was analyzed with an ANOVA test at a 0.05 level of significance.
Results and Conclusion: 54% had a normal femoral roll-back during knee flexion after TKA, 13% had no significant roll-back and 33% had a paradoxical femoral roll-forward. 65% had a normal tibia internal rotation during knee flexion, 16% had no significant tibia rotation and 19 had a paradoxical tibia external rotation.
The mean Knee Score was 92/100 points. The mean Function Score was 88/100 points. There was no correlation between the post-operative kinematic behavior and the Knee Score. There was a significant correlation between the post-operative kinematic behavior and the Function Score, with better score for the patients having a physiological femoral roll-back and a physiological tibial internal rotation during knee flexion.
It is possible to record the kinematic behavior of a knee intra-operatively during total knee replacement. However, only passive kinematic may be analyzed, and it might be significantly different from the active kinematic after the procedure. Furthermore, this software allows a kinematic registration of the antero-posterior stability, which is not commonly displayed by usual navigation system. Despite these limitations, it seems that the restoration of a more physiological kinematic impacts positively the functional outcome of the TKR. Intra-operative analysis of the kinematic of the knee during total knee replacement may offer the chance to modify the kinematic behavior of the implant and to choose the best fitted constraint to the patient's native knee in order to impact positively the functional result.
