Bone patellar tendon bone graft for ulnar collateral ligament reconstruction: a biomechanical study

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Sports Medicine

Background:

• Ulnar collateral ligament (UCL) tears are common in overhead athletes, often requiring lengthy surgical recovery.
• Investigating alternative UCL reconstruction methods is crucial to potentially decrease recovery time.

Purpose of the Study:

• To compare the biomechanical properties of standard palmaris longus versus novel bone-patellar tendon-bone (BTB) reconstruction for UCL tears.
• To evaluate graft integrity and failure modes under cyclic and load-to-failure testing.

Main Methods:

• Utilized 16 fresh frozen cadaver upper extremities and 8 cadaver knees for biomechanical testing.
• Compared native UCL properties with reconstructions using palmaris longus and BTB grafts with interference screw fixation.
• Subjected specimens to cyclic loading followed by load-to-failure testing to assess performance and failure mechanisms.

Main Results:

• Native UCL properties were consistent across groups; palmaris reconstruction showed no significant difference from the native UCL.
• Palmaris longus reconstruction exhibited a significantly higher torque at failure (13.7 ± 4.9 Nm) compared to BTB reconstruction (5.9 ± 1.0 Nm).
• BTB grafts had a high failure rate (7/8) during cycling, primarily at the humeral-sided bone-tendon interface.

Conclusions:

• Ulnar collateral ligament reconstruction with BTB grafts fixed by interference screws demonstrates a high failure rate at the bone-tendon junction.
• Standard palmaris longus UCL reconstruction remains biomechanically equivalent to the native ligament and is the preferred graft option between the two.
• These findings suggest that palmaris longus should be the preferred graft for UCL reconstruction over BTB with interference screw fixation based on current biomechanical data.