Can a simple fall cause a rotator cuff tear? Literature review and biomechanical considerations

Abstract

Purpose: A simple fall on the shoulder is often referred to as minor trauma that cannot cause a tendon tear but at best reveal a pre-existing rotator cuff pathology. We wanted to know whether this statement was true. The purpose of our study was therefore to summarize the causes of acute rotator cuff tears reported in the literature and provide a biomechanical explanation for tendon tears diagnosed after a fall.

Method: We searched PubMed and included studies reporting rotator cuff tears occurring due to a trauma. The number of cases, the tendons involved, the age of the patients, and the nature of trauma were summarized. In addition, we noted any information provided by the authors on the pathogenesis of acute tendon ruptures.

Results: Sixty-seven articles with a total of 4061 traumatic rotator cuff tears met the inclusion criteria. A simple fall was the most common cause (725 cases) and the supraspinatus tendon was most frequently affected. The postulated pathomechanism is a sudden stretch of the tendon-muscle unit while contracting (eccentric loading).

Conclusion: A simple fall can cause an acute rotator cuff tear and fall-related tears are not restricted to young individuals. They can affect patients of any age. The stresses occurring within the rotator cuff during an attempt to cushion a fall may locally exceed the tensile strength of the tendon fibers and cause a partial or full-thickness tear.

Keywords: Fall; Injury; Rotator cuff tear; Shoulder; Trauma.

Fig. 1

Coronal and sagittal MR images of the right shoulder of a 37-year-old man showing a full-thickness supraspinatus tendon tear. The examination was made seven weeks after a fall on the shoulder following a header duel during a football match. Despite the young age, immediate pain, initial pseudoparesis, and normal muscle trophics, the insurance expert claimed that the accident had only caused a contusion and that the tendon was already torn before the event

Fig. 2

Drawings of a typical fall. The subject attempts to avoid to hit the floor with his face and uses the arms to attenuate the impact on the ground. Most falls are to the side (a), loading the posterosuperior rotator cuff or the front (b), loading the anterosuperior rotator cuff

Fig. 3

Illustration of the lateral plank exercise. When the arm is abducted 90°, the force under the elbow is about 0.64 body weight and directed to the shoulder. The moment in the shoulder is small and the body can be kept in balance. When the arm is brought against the body, the ground reaction force under the elbow F1(α) increases slightly, the lever arm and the moment M(α) in the shoulder to maintain balance, however, increase rapidly

Fig. 4

Graph representing the moment M(α) that the shoulder muscles must generate to keep a person weighing 84 kg in the lateral plank position as a function of the abduction angle (α) of the arm (red dots). The maximum moment that the shoulder muscles of healthy volunteers can generate is taken from previous studies and represented with separate marks. At an abduction angle of about 60° or less, the moment necessary to stabilize the body exceeds the moment that the shoulder muscles can generate and the arm is forced to the side, resulting in an eccentric loading of the rotator cuff and an impact of the shoulder on the ground