MCL internal brace does not fully recapitulate normal MCL function in valgus stress.

Area of Science:

• Orthopedic biomechanics
• Sports medicine
• Anatomy

Background:

• Medial collateral ligament (MCL) injuries are common in knee trauma.
• Internal bracing is a surgical technique to stabilize the MCL.
• Cadaveric studies are crucial for understanding biomechanical performance.

Purpose of the Study:

• To evaluate the effectiveness of two internal brace constructs in preventing medial gapping under valgus load.
• To compare the biomechanical performance of internal bracing against an intact MCL.

Main Methods:

• Eight pairs of cadaver knees were tested.
• Two internal brace constructs using FiberTape were applied to the MCL.
• Valgus stress (10 Nm) was applied at 20 degrees flexion.
• Medial joint space opening was measured under intact, grade 2, and grade 3 MCL tear conditions.

Main Results:

• Both constructs showed increased medial gapping with MCL tears compared to intact knees.
• Construct I failed at the femoral attachment and did not maintain tension.
• Construct II maintained tension but did not restore joint opening to the intact state.

Conclusions:

• Construct II demonstrated improved performance over Construct I in maintaining tension.
• Neither construct fully restored knee stability to the intact state under valgus stress.
• Clinicians should be aware of the limitations of this internal bracing technique.