Israel Medical Association Journal

Background: Previous epidemiological studies on shoulder instability evaluated specific and relatively small subgroups of patients.

Objectives: To determine the incidence rate of primary shoulder dislocations.

Methods: Cohort analysis of electronic health records from 2004 to 2019 was conducted in a urban district of a major health maintenance organization (HMO) in Israel. Patients presented with primary shoulder dislocation that was treated with closed reduction in any medical facility within the district. Overall incidence density rates (IDR) of primary shoulder dislocations and stabilization surgeries were determined.

Results: Over a period of 16 years 13,158 patients underwent closed reduction of primary shoulder dislocation. Of those, 712 shoulder stabilization surgeries were performed (5%). The IDR of primary shoulder dislocations were 124 per 100,000 person-years. The IDR of primary shoulder stabilizations were 7 per 100,000 person-years. The peak in the number of dislocations was observed in those 20–29 years old and ≥ 60 years of. In patients under 59 years old, dislocations were more common in men. In those ≥ 60 years of age, dislocations were more common in women. Most shoulder stabilization surgeries were performed on young patients. The annual mean time from the first dislocation to stabilization surgery linearly declined to 6 months in 2019.

Conclusions: The IDR of primary shoulder dislocations calculated from the largest HMO in Israel were 124 per 100,000 person-years. Shoulder dislocations had bimodal age distribution. Overall, 5% of the patients (mainly young) with shoulder dislocations underwent shoulder stabilization surgery during the study period.

Background: Injuries to the anterior cruciate ligament (ACL) are common and complete tears often fail to heal. ACL reconstruction is considered the surgical gold standard of care for ACL injuries in young active patients.

Objectives: To determine the corresponding morphological and histological features of the torn ACL in different time periods after injury.

Methods: The study included 28 remnant specimens of torn ACLs from patients who had ACL reconstruction surgery of the knee. The remnant pathology was evaluated by its morphology during arthroscopy and by histopathologic measurements.

Results: At surgery there were three progressive and distinct morphological tear patterns. The first pattern was noticed within the first 3 months from injury and showed no scar tissue. The second pattern appeared later and was characterized by the appearance of scar tissue with adhesion to the femoral wall. The third pattern was characterized by adhesion of the ACL remnant to the posterior cruciate ligament. The histological changes of the first morphological pattern showed abundance of blood vessels and lymphocytes at the torn femoral end with few irregular collagen fibers. The second and third tear patterns showed decrement in the number of blood vessels and lymphocytes with longitudinally oriented collagen fibers.

Conclusions: The morphological features of the ACL remnant in the first 3 months after injury showed no scar tissue and its histological features had the characteristics of a reparative phase. This phase was followed by a prolonged remodeling phase that ended with attachment of the remnant to the posterior cruciate ligament.