Anterior cruciate ligament: an anatomical exploration in humans and in a selection of animal species.

PURPOSE: Many anatomical anterior cruciate ligament (ACL) studies have indicated that the human ACL is composed of two functional bundles: the antero-medial (AM) and postero-lateral (PL). The purpose of this study is to compare the ACL anatomy among human and assorted animal species. METHODS: Twenty fresh-frozen knees specimen were used: five humans, ten porcine, one goat, one Kodiak bear, one African lion, one Diana monkey and one Gazelle antelope. All the specimens were dissected to expose the ACL and to visualize the number of bundles and attachment patterns on the tibia and femur. Following the fibre orientation of the individual bundles, a wire loop was used to bluntly separate the bundles starting from the tibial insertion site to the femoral insertion site. In the human and porcine ACL, each bundle was separated into approximately 2 mm diameter segments and then tracked in order to establish the individual bundle's specific pattern of insertion on the femur and tibia. RESULTS: It appeared that all human and animal knee specimens had three bundles that made up their ACL. In addition, it was noted that among the various specimens species, all viewed with an anterior view, and at 90° knee flexion, the ACL bony insertion sites had similar attachment patterns. CONCLUSION: In all the specimens, including human, the ACL had three distinct bundles: AM, intermediate (IM) and PL. The bundles were composed of multiple fascicles arranged in a definite order and similar among the different species.

Postoperative death associated with a reverse prosthesis.

The mortality rate after total shoulder arthroplasty, and specifically after reverse total shoulder arthroplasty, has not received much attention in the literature. Although complications of the reverse total shoulder arthroplasty are well known, fatalities secondary to complications related to the unique features of the reverse prosthesis have not, to our knowledge, been previously reported. We report the case of an elderly man who developed shoulder instability after the implantation of a reverse prosthesis followed by disassociation of the glenosphere from the baseplate. After a reoperation to revise and reassemble the components, he developed an infected shoulder and sepsis, and subsequently died from the complications of sepsis. This death represents a perioperative mortality rate of 0.5% in our series of 190 cases. The mortality rate after reverse total shoulder seems to be similar to that after standard total shoulder arthroplasty.

Malignant soft tissue tumors of the biceps muscle mistaken for proximal biceps tendon rupture.

Tears of the proximal long head of the biceps tendon are among the most common tendon tears in the body. In most cases, the diagnosis is easily determined based on the history and physical examination. However, malignant soft tissue tumors can simulate proximal biceps tendon tears. Although tumors simulating tears of the distal biceps tendon at the elbow have been reported, to the authors' knowledge, no previous cases of tumors simulating or being mistaken for proximal biceps tendon tears have been reported.This article describes 2 cases of malignant sarcomas initially mistaken for tears of the long head of the biceps tendon. In the first case, a 62-year-old woman developed swelling in her arm after feeling a twinge in her shoulder. A magnetic resonance imaging scan was misread as a biceps tendon tear and not treated by the examining physician. In the second case, a mass appeared with little trauma in the brachium of a 70-year-old man. On physical examination, the mass was hard to palpation. In each case, biopsy revealed a soft tissue sarcoma. Both patients underwent wide excision with radiation and are currently disease free. These 2 cases emphasize the importance of obtaining a good history and of performing a thorough shoulder and arm examination in patients with deformities consistent with tears of the long head of the biceps tendon.