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A reconstruction of the anterior bundle of the ulnar collateral ligament of the elbow using bone anchors was compared regarding strain and valgus load strength with the intact ulnar collateral ligament and the reconstructed ulnar collateral ligament using bone tunnels. In both normal and reconstructed elbows, the anterior band and posterior band were tight during only a portion of the range of motion. Toward extension, the mean peak strain in the anterior band was tight for the normal and bone anchor groups, but lax in the bone tunnel group. Toward extension, the mean peak strain in the posterior band was lax in all elbows. Toward flexion, the strain in the anterior band was lax in the normal and bone anchor groups, but tight in the bone tunnel group. The mean of the peak strains for the posterior band toward flexion was tight for all elbows. Mean valgus load strength of normal elbows was 22.7 +/- 9.0 N.m. The bone tunnel and bone anchor mean strengths were 76.3% and 63.5%, respectively, of normal elbow strength. We concluded that the bone anchor reproduced the normal anatomy and mechanical function of the ulnar collateral ligament more closely than the bone tunnel, and that both reconstruction methods were significantly weaker than the normal ulnar collateral ligament. However, we found no significant difference in reconstruction strength between bone anchor and bone tunnel.

Thirty-two patients with acute, complete tears of the anterior cruciate ligament (ACL) proved at surgery underwent examination with magnetic resonance (MR) imaging. Bone impaction sites were present in the posterolateral tibial plateau in 30 patients (94%) and in the lateral femoral condyle (LFC) in 29 patients (91%). The bone abnormalities had low signal intensity on T1-weighted images and high signal intensity on T2-weighted images when compared with the signal intensity of normal marrow. It is assumed that the bone changes occur during injury when the LFC impacts into the posterior tibia, either during the initial rotary subluxation or as the LFC recoils to return to anatomic alignment. Only one of six partial ACL tears had a bone signal change. In patients with acute knee injury, bone impaction sites in the posterolateral tibia and the LFC suggest that a complete ACL tear is present.