Strength Based on In Vitro Studies

Both the soft tissues and the articulation of the joint afford stability to the elbow. These stabilizers include the medial and lateral collateral ligaments and the articulation of the humeroradial and humeroulnar joints. Morrey and An conducted a cadaveric study investigating the ar ticular and ligamentous contributions to the stability of the elbow joint.11 Using four cadavers, they analyzed the stability of the joint or the contributions to resisting varus stress, valgus stress, and joint distraction in extended and 90° flexed positions. In the flexed position, the results indicated that the medial collateral ligament, or ulnar collateral ligament, provided 54% of the varus torque needed to resist the valgus stress. The soft tissues and capsule provided 10% of the resistance to valgus stress, and osseous articulation provided approximately 33% of the resistance. In the extended position, the medial collateral ligament provided 31% of the resistance, with the capsule and joint articulation providing 38% and 31%, respectively. The lateral collateral ligament, anconeus, and joint capsule provided stability for resisting varus stress. At 90° of flexion, the lateral collateral ligament contributed 9% of the valgus torque needed to resist varus stress, and the joint articulation and joint capsule provided 75% and 13%, respectively. In the extended position, joint articulation provided 55% of the resistance to varus stress, and the lateral collateral ligament and joint capsule provided 14% and 32%, respectively. Resistance to joint distraction was dependent on the position of the elbow. At 90° of flexion, the medial collateral ligament primarily provided 78% of the resistance to distraction. The lateral collateral ligament contributed 10%, and the joint capsule provided 8%. In the extended position, the contribution to distraction resistance was reversed; the joint capsule provided 85% of the resistance, and the lateral and medial collateral ligaments provided 5% and 6%, respectively.

Dillman et al. measured the ultimate tensile strength of the medial collateral ligament.12 Using 11 cadaveric elbows, they determined that the ultimate tensile strength of the medial collateral ligament was 642 N before failure. This measurement is equivalent to providing approximately 32 N-m of varus torque to resist valgus stress (using 0.05 m as the moment arm length). Note that the authors of this study investigated the ultimate tensile strength of the ligament. With a large number of loading cycles, the failure load would be less than the ultimate tensile limit. Regan et al. conducted a biomechanical study of ligaments around the elbow, including the lateral collateral ligament and the anterior and posterior bundles of the medial collateral ligament.13 They determined that the anterior bundle of the medial collateral ligament was the strongest (260-N failure load) and stiffest (1528 N) among these ligaments. The palmaris longus required a 357-N load to achieve failure. The results of this study support the use of the palmaris longus tendon as reconstructive tissue.

The amount of force experienced across the elbow depends on a number of factors including the type of load and the positioning of the hand and elbow. Askew et al. conducted a study measuring the isometric elbow strength in a group of normal individuals (50 men and 54 women)

ranging in age from 21 to 79 years.14 The isometric strength measurements, which were determined by using a custom torque cell dynamometer with the elbow flexed to 90°, included a flexion torque of 71 N-m for men and 33 N-m for women. Supination torque was 9 N-m for men and 4 N-m for women. They generally concluded that the mean extension torque was 61% of flexion torque and that the mean pronation torque was 86% of supination torque. Various models have estimated that forces equal to several times body weight are transmitted across the elbow.15,16

Amis et al. developed a three-dimensional model for quantifying joint forces for various activities, including maximal flexion, extension, pulling, abduction, and ad-duction.15 During isometric flexion, the model estimated humeroradial and humerocoronoid forces of 3200 N at 30° of flexion. During isometric extension, the peak humeroulnar force was approximately 3200 N at 120° of flexion. According to An and Morrey, the accuracy of these models depends on the number of muscles included and whether antagonistic muscle activity is included.5 Halls and Travill implanted transducers in cadaveric forearms to measure the distribution of forces across the el-bow.17 They determined that 57% of an applied axial force across the elbow is transferred to the humerus through the radiocapitellar joint and 43% is transferred through the ulnotrochlear joint.

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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