Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus...

Area of Science:

• Orthopedic surgery
• Biomechanics
• Sports medicine

Background:

• Medial collateral ligament (MCL) injuries often require reconstruction (MCLR).
• Knee valgus alignment can impact the biomechanical integrity of MCLR.

Purpose of the Study:

• To quantify the forces acting on a single-bundle MCLR in relation to varying degrees of knee valgus alignment.
• To assess the influence of valgus deformity on MCLR under dynamic loading conditions.

Main Methods:

• Eight human cadaveric knees underwent dynamic valgus loading.
• A single-bundle MCLR using hamstring autograft was performed.
• Medial opening wedge osteotomies gradually introduced 0° to 10° valgus, with MCLR forces measured at different flexion angles.

Main Results:

• Increased valgus malalignment significantly elevated forces on the MCLR across all tested knee flexion angles (p < 0.05).
• At 5° valgus, MCLR forces ranged from 16.2 N to 18.5 N.
• At 10° valgus, MCLR forces increased to a range of 29.4 N to 40.0 N.

Conclusions:

• Valgus knee malalignment substantially increases stress on reconstructed medial collateral ligaments.
• For chronic medial instabilities with ≥5° valgus deformity, concurrent realigning osteotomy with MCLR is recommended to enhance graft protection and reduce failure rates.