Compreendendo as lesões das raízes posteriores dos meniscos: da ciência básica ao tratamento

Effect of meniscus modelling assumptions in a static tibiofemoral finite element model: importance of geometry over material

Finite element studies of the tibiofemoral joint have increased use in research, with attention often placed on the material models. Few studies assess the effect of meniscus modelling assumptions in image-based models on contact mechanics outcomes. This work aimed to assess the effect of modelling assumptions of the meniscus on knee contact mechanics and meniscus kinematics. A sensitivity analysis was performed using three specimen-specific tibiofemoral models and one generic knee model. The assumptions in representing the meniscus attachment on the tibia (shape of the roots and position of the attachment), the material properties of the meniscus, the shape of the meniscus and the alignment of the joint were evaluated, creating 40 model instances. The values of material parameters for the meniscus and the position of the root attachment had a small influence on the total contact area but not on the meniscus displacement or the force balance between condyles. Using 3D shapes to represent the roots instead of springs had a large influence in meniscus displacement but not in knee contact area. Changes in meniscus shape and in knee alignment had a significantly larger influence on all outcomes of interest, with differences two to six times larger than those due to material properties. The sensitivity study demonstrated the importance of meniscus shape and knee alignment on meniscus kinematics and knee contact mechanics, both being more important than the material properties or the position of the roots. It also showed that differences between knees were large, suggesting that clinical interpretations of modelling studies using single geometries should be avoided.

Meniscal Root Repair Alone or Combined with Different Procedures After at Least 6 Months of Follow-Up: A Series of Cases

Purpose

To analyze clinical and functional outcomes of patients submitted to posterior meniscal root repair of the medial or lateral meniscus in different settings, with at least 6 months of follow-up.

Patients and Methods

Retrospective multicentric study assessing epidemiological characteristics and clinical-functional results of 22 patients who underwent meniscal root reinsertion (MRR) by transtibial technique. This study addressed different settings: isolated medial root repair, medial root repair associated with high tibial osteotomy (HTO) and lateral root repair associated with anterior cruciate ligament (ACL) reconstruction.

Results

Twelve patients had an isolated tear of the posterior root of the medial meniscus and underwent MRR alone. Six patients had a varus axis >5°, undergoing MRR in addition to HTO in the same surgical procedure. Four patients underwent repair of the posterior root of the lateral meniscus associated with simultaneous reconstruction of the ACL. The main results of the study were observed in the improvement of the IKDC score from 27.7% preoperatively to 69.8% in the postoperative period (p < 0.0001) and the Lysholm score of 44.4 points preoperatively to 88.4 points in the postoperative period (p < 0.0001). Significant clinical and subjective improvements were also reported.

Conclusion

Medial meniscal root repair, associated or not with valgus tibial osteotomy (when indicated) and lateral meniscal root repair associated with ACL reconstruction, improved clinical, functional, and subjective results of the patients presented in this case series in the short term.

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