An In Vitro Biomechanical Analysis of the Contributions of Medial Ligaments to the Stability of the PCL-Deficient Knee
Notice bibliographique
Résumé
Objectives: Approximately 95% of PCL injuries are multi-ligament injuries, yet it remains unclear if simultaneous injuries sustained to medial-side knee stabilizers such as the posterior oblique ligament (POL) and deep medial collateral ligament (dMCL) also need to be addressed. Pathomechanical kinematics that still exists after PCL reconstructions may be the result of residual instability due to deficiency of these secondary stabilizers. The objective of this study is to characterize the relative contributions of the POL, dMCL and superficial medial collateral ligament (sMCL) in PCL-deficient knees. We hypothesize that the POL would contribute to stability in extension only, whereas the dMCL would provide stability throughout the entire flexion range of motion. Methods: Eight specimens (aged 40-63, 5 female, 1 male, 2 pairs) were potted and the PCL was dissected arthroscopically. Each specimen was mounted onto a VIVO joint motion simulator (AMTI) and flexed from 0 to 90 degrees with a 10 N compressive load applied along the long axis of the tibia. During this motion, a 5 Nm internal or external moment was applied to the tibia, and the resulting kinematics were recorded. Recorded kinematics were applied back on the specimen, while the joint’s reaction torque to this rotation was measured. The decrease in reaction torque was measured following randomized dissection of the POL and dMCL (4 POL first and 4 dMCL first); the sMCL was always dissected last. The contribution of each ligament to this reaction torque was measured by calculating the change in the reaction torque caused by the ligament’s dissection at 0, 30, 60 and 90 degrees. Each ligament’s relative contribution was compared to the net reaction torque of the joint to calculate the percentage contribution of the ligament. The contribution of each ligament was analyzed using a one-way repeated measure ANOVA with a significance value of 0.05. Results: With an internal torque applied, the dMCL’s contribution to the reaction torque was greatest at 30 degrees, accounting for up to 23% +/- 19% of the overall reaction torque; its contribution was not significantly affected by flexion angle (p>0.05). The POL’s contribution was significantly affected by flexion angle (p=0.007), accounting for 40% +/- 15% of the reaction torque at 0 degrees but only 6% +/- 4% at 90 degrees. The sMCL’s contribution was also sensitive to flexion angle (p=0.006), accounting for 14% ± 16% of the reaction torque at 0 degrees and increasing to 28% +/- 12% at 90 degrees. With an external torque applied, the dMCL’s contribution accounted for 12% +/- 4% of the reaction torque at 0°, but this decreased to 4% +/- 2% at 90 degrees; its contribution was significantly affected by flexion angle (p=0.038). The POL’s contribution accounted for 12% +/- 3% of the reaction torque at 0 degrees and 3% +/- 3% at 90 degrees and the flexion angle changed this contribution significantly (p=0.003). A large portion of the reaction torque was provided by the sMCL, accounting for 52% +/- 7% at 90 degrees. Conclusions: Our results show that, with internal torques applied to the tibia, the POL plays an important role in resisting motion when the joint is near full extension. Conversely, the dMCL’s (and sMCL’s) contribution is largest in flexion. Neither the POL nor dMCL have a large contribution towards resisting external tibial torques; the sMCL seems to be the primary ligament resisting external rotation among medial ligaments. Thus, there is the potential for increased posteromedial instability if POL and dMCL injuries are not addressed, increasing the risk of a failed PCL reconstruction.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».