The impact of ulnar collateral ligament tear and reconstruction on contact pressures in the lateral compartment of the elbow

Isolated displaced type II partial articular radial head fracture: correlation of preoperative imaging with intraoperative findings of lateral ulnar collateral ligament tear

“…Displacement of RHF contributes to elbow instability, and biomechanical studies demonstrated that even an isolated RHF, with a preserved medial collateral ligament complex, can induce up to 30% loss of elbow resistance. 6,10,30,31 Unstable RHFs were associated with complete avulsion of the LUCL, particularly in the group with posterior displacement of the fragment. Intraoperative findings prompt us to propose a cadaveric model of lateral ligament injury demonstrating that when the radial head is posteriorly dislocated, the displaced fragment can follow the torn LUCL posteriorly (posterior displacement model); alternatively, when it remains anteriorly dislocated, it is less commonly associated with partial or total LUCL tear (anterior displacement model).…”

“…Radial head fractures (RHFs) constitute 1.5%-4% of all fractures of the human body and account for approximately 33% of adult elbow fractures; they mainly involve active individuals between 20 and 60 years of age. [9][10][11][12][13][14][15][16][17] RHFs can be nondisplaced, minimally displaced, or completely displaced with comminution. 18 Classification systems used for RHF take into account the appropriate treatment of each pattern of bone injury.…”

Computing Muscle, Ligament, and Osseous Contributions to the Elbow Varus Moment During Baseball Pitching

“…9 In our simulations, the offset distance ( d art ) from the varus-valgus joint center to the center of pressure was defined to be half the length of the vector from the joint center to the lateral edge of the radius, perpendicular to the varus-valgus axis of rotation. For each time step in which the pitching motion imposed a valgus load at the elbow joint, we solved Equations (2) and (3), to calculate the moment supported by the UCL (assuming $M_{mt}^i=M_{\mathit{Hill}}^i$).…”

“…24,37,40 Examinations of elbow physiology in vitro have also revealed that muscle contraction generates joint compression. 9,13 Under a valgus load, the moment generated by the osseous articulation is a function of the compression force between the radius and humerus. 9,13 Increased compression can be dangerous, especially for young pitchers with immature skeletons, because it has been shown to result in bone impairments such as Panner’s disease and osteochondritis dissecans in over 6% of the youth pitcher population.…”

Elbow Instability

“…With repetitive overuse and/or poor mechanics in throwing athletes, degeneration or acute tears of the MUCL can result. Reconstruction of the anterior bundle of the MUCL has been shown to restore radiocapitellar articular pressures under valgus force to nearly normal values, demonstrating the importance of anterior bundle of the MUCL and the effectiveness of surgery [ 18 ].…”