Ligamentous and capsular restraints to experimental posterior elbow joint dislocation

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Sports Medicine

Background:

• Pathological external forearm rotation (PEFR) is associated with posterolateral elbow instability.
• PEFR is a potential precursor to simple posterior elbow joint dislocations.

Purpose of the Study:

• To investigate the capsuloligamentous structures that resist PEFR.
• To elucidate the role of specific elbow joint stabilizers in preventing PEFR and subsequent dislocation.

Main Methods:

• Utilized 18 elbow joint specimens in a specialized experimental dislocation system.
• Performed sequential dissection of capsular and ligamentous structures.
• Assessed joint stability against PEFR after each structural removal.

Main Results:

• In elbow extension, the anterior capsule and lateral collateral ligament complex (LCLC) were primary stabilizers against PEFR.
• In elbow flexion, the anterior capsule offered no significant stabilization against PEFR.
• The LCLC was the sole immediate stabilizer against PEFR in flexed positions, crucial for preventing posterolateral instability and posterior dislocation.
• The medial collateral ligament did not directly stabilize against PEFR but limited the final stage of posterior dislocation.

Conclusions:

• The LCLC is a critical stabilizer against PEFR, particularly in flexed elbow positions, thus mitigating posterolateral instability.
• The anterior capsule contributes significantly to PEFR resistance in elbow extension but not in flexion.
• The medial collateral ligament plays a role in preventing the complete posterior dislocation rather than initial PEFR.