Variations in Rupture Site and Surface Strains at Failure in the Maturing Rabbit Medial Collateral Ligament

1995 ◽  
Vol 117 (4) ◽  
pp. 455-461 ◽  
Author(s):  
T. C. Lam ◽  
N. G. Shrive ◽  
C. B. Frank
Keyword(s):  
Medial Collateral Ligament ◽  
Surface Strain ◽  
Collateral Ligament ◽  
Anterior Portion ◽  
Femoral Insertion ◽  
Tibial Insertion ◽  
Medial Side ◽  
Optical Strain Measurement ◽  
Optical Strain

The relationship between the pattern of surface strain and the site of failure in maturing rabbit ligaments was studied in vitro. Bone-medial collateral ligament (MCL)-bone complexes of 24 female New Zealand White rabbits at 3, 6, 9 and 12 months of age (n = 6 rabbits, 12 MCLs per group) were tested in tension to failure. A video dimension analysis (VDA) system was used to map the surface strain at failure across the width and along the length of the medial side of each MCL during testing. Results showed that the highest strains were consistently located at the femoral insertion decreasing towards the midsubstance, with the highest strain occurring in the anterior portion of the MCL immediately adjacent to the femoral insertion. Strains of the complex at failure increased with rabbit maturation. The strain distribution however, did not change dramatically, even though the locations of MCL failure changed from exclusively tibial avulsion in the three month old rabbits to predominantly midsubstance failures in the 12 month old rabbits. In the six month old rabbits, there was a particular dissociation with all MCLs failing near the tibial insertion while femoral strains were apparently the highest. These results suggest two possibilities beyond that of some unknown artifacts of optical strain measurement. First, since failure sites rarely correlated with areas of maximum surface strain in this study, it seems possible that higher strains could exist deeper in the tissue, particularly at the bone-ligament interface of the tibial insertion in immature animals and somewhere within the midsubstance of the MCL in the adult. Secondly, it is possible that the ligament material may be heterogeneous.

The Effectiveness of a Hinged Elbow Orthosis in Medial Collateral Ligament Injuries: An In Vitro Biomechanical Study

2019 ◽  
Vol 47 (12) ◽  
pp. 2827-2835
Author(s):  
Ranita H.K. Manocha ◽  
James A. Johnson ◽  
Graham J.W. King
Keyword(s):  
Medial Collateral Ligament ◽  
Muscle Activation ◽  
Mechanical Stability ◽  
Biomechanical Study ◽  
Return To Play ◽  
Collateral Ligament ◽  
Valgus Stress ◽  
Active Motion ◽  
Early Return

Background: Medial collateral ligament (MCL) injuries are common after elbow trauma and in overhead throwing athletes. A hinged elbow orthosis (HEO) is often used to protect the elbow from valgus stress early after injury and during early return to play. However, there is minimal evidence regarding the efficacy of these orthoses in controlling instability and their influence on long-term clinical outcomes. Purpose: (1) To quantify the effect of an HEO on elbow stability after simulated MCL injury. (2) To determine whether arm position, forearm rotation, and muscle activation influence the effectiveness of an HEO. Study Design: Controlled laboratory study. Methods: Seven cadaveric upper extremity specimens were tested in a custom simulator that enabled elbow motion via computer-controlled actuators and motors attached to relevant tendons. Specimens were examined in 2 arm positions (dependent, valgus) and 2 forearm positions (pronation, supination) during passive and simulated active elbow flexion while unbraced and then while braced with an HEO. Testing was performed in intact elbows and repeated after simulated MCL injury. An electromagnetic tracking device measured valgus angulation as an indicator of elbow stability. Results: When the arm was dependent, the HEO increased valgus angle with the forearm in pronation (+1.0°± 0.2°, P = .003) and supination (+1.5°± 0.0°, P = .006) during active motion. It had no significant effect on elbow stability during passive motion. In the valgus position, the HEO had no effect on elbow stability during passive or active motion in pronation and supination. With the arm in the valgus position with the HEO, muscle activation reduced instability during pronation (–10.3°± 2.5°, P = .006) but not supination ( P = .61). Conclusion: In this in vitro study, this HEO did not enhance mechanical stability when the arm was in the valgus and dependent positions after MCL injury. Clinical Relevance: After MCL injury, an HEO likely does not provide mechanical elbow stability during rehabilitative exercises or when the elbow is subjected to valgus stress such as occurs during throwing.

scholarly journals Length change pattern of the medial structures of the knee and related reconstructions

2020 ◽  
Vol 8 (9_suppl7) ◽  
pp. 2325967120S0053
Author(s):  
Arne Olbrich ◽  
Elmar Herbst ◽  
Christoph Domnick ◽  
Johannes Glasbrenner ◽  
Michael J. Raschke ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Knee Flexion ◽  
Insertion Site ◽  
Length Change ◽  
Collateral Ligament ◽  
Femoral Insertion ◽  
Superficial Medial Collateral Ligament ◽  
Custom Made ◽  
Length Changes ◽  
Length Reduction

Introduction: Aim of the study was to investigate the length changes of the medial structures and related reconstructions. It was assumed that the three fibre sections (anterior/middle/posterior) of the superficial medial collateral ligament (sMCL) have different length change patterns, which cannot be imitated by current reconstructions. Hypotheses: The three fibre sections (anterior/middle/posterior) of the superficial medial collateral ligament (sMCL) cannot be imitated by current reconstructions. Methods: Measurements were made on eight cadaveric knees. The knee joints were clamped in a custom-made open chain extension structure. For this purpose, the portions of the quadriceps and the iliotibial tract were aligned according to their fibre direction and statically loaded using hanging weights. The respective tibial and femoral insertion points of the sMCL anterior/middle/posterior fibres were marked by small pins. Similarly, pins were inserted at the tibial and femoral attachment sites of the posterior oblique ligament (POL). In order to imitate the Lind reconstruction, a pin was additionally inserted on the tibial semitendinosus insertion site. Pin combinations accounting for the anterior/middle/posterior sMCL, the POL, and the Lind reconstruction were connected using a high resistant suture. Then the length change patterns were measured using a rotary encoder from 0-120° knee flexion. Statistical analysis was performed using 2-way repeated-measures ANOVA and a post-hoc Bonferroni correction (p <0.05). Results: The anterior and posterior fibres of the sMCL showed a reciprocal behaviour (p< 0.001). The anterior fibres showed a length reduction (2%) up to a flexion of 20°, followed by an elongation of 5% at 120° flexion, which means that the anterior fibres are tight in knee flexion. Conversely, the posterior fibres of the MCL showed an initial length reduction of 4% at 20° flexion. This was followed by an isometric range (20° - 80°) and a further length reduction of 8% in deep flexion (120°). Thus, the posterior fibres of the MCL were tight in extension. The three parts of the POL showed a constant reduction of 25% between 0° and 120°. The Lind reconstruction with the tibial pin at the semitendinosus insertion site showed similar length changes compared to the sMCL (n.s.). Furthermore, the Lind reconstruction was dependent on the femoral placement of the pins (p <.001). The tibial placement had no significant influence. Conclusion: The anterior portion of the sMCL was tight in flexion, whereas the posterior portion was tight in extension. This reciprocal behavior could not be imitated by a single point to point reconstruction. When surgically applying these reconstructions, special attention should be paid to the femoral insertion.

Rehabilitation of the medial collateral ligament-deficient elbow: An in vitro biomechanical study

2000 ◽  
Vol 25 (6) ◽  
pp. 1051-1057 ◽  
Author(s):  
April D. Armstrong ◽  
Cynthia E. Dunning ◽  
Kenneth J. Faber ◽  
Teresa R. Duck ◽  
James A. Johnson ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Biomechanical Study ◽  
Collateral Ligament
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