[Biomechanical evaluation of the valgus stability of elbow after reconstruction]

Abstract

Objective: To evaluate of the valgus stability of the elbow after excision of the radial head, release of the medial collateral ligament (MCL), radial head replacement, and medial collateral ligament reconstruction.

Methods: Twelve fresh human cadaveric elbows were dissected to establish 7 kinds of specimens with elbow joint and ligaments as follow: (1) intact (n=12); (2) release of the medial collateral ligament (n=6); (3) excision of the radial head (n=6); (4) excision of the radial head together with release of the medial collateral ligament (n=12); (5) radial head replacement (n=6); (6) medial collateral ligament reconstruction (n=6); (7) radial head replacement together with medial collateral ligament reconstruction (n=12). Under two-newton-meter valgus torque, and at 0, 30, 60, 90 and 120 degrees of flexion with the forearm in supination, the valgus elbow laxity was quantified: All analysis was performed with SPSS 10.0 software.

Results: The least valgus laxity was seen in the intact state and its stability was the best. The laxity increased after resection of the radial head. The laxity was more after release of the medial collateral ligament than after resection of the radial head (P<0.01). The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head, so its stability was the worst. The laxity of the following implant of the radial head decreased. The laxity of the medial collateral ligament reconstruction was as much as that of the intact ligament (P>0.05). The laxity of the radial head replacement together with medial collateral ligament reconstruction became less.

Conclusion: The results of this study show that the medial collateral ligament is the primary valgus stabilizer of the elbow and the radial head was a secondary constraint to resist valgus laxity. Both the medial collateral ligament reconstruction and the radial head replacement can restore the stability of elbow. If the radial head replacement can not be carried out, the reconstruction of the medial collateral ligament is acceptable.