Shoulder posterior internal impingement in the overhead athlete

Abstract

Posterior internal impingement (PII) of the glenohumeral joint is a common cause of shoulder complex pain in the overhead athlete. This impingement is very different from standard outlet impingement seen in shoulder patients. Internal impingement is characterized by posterior shoulder pain when the athlete places the humerus in extreme external rotation and abduction as in the cocking phase of pitching or throwing. Impingement in this position occurs between the supraspinatus and or infraspinatus and the glenoid rim. Understanding regarding this pathology continues to evolve. Definitive understanding of precipitating factors, causes, presentation and methods of treatment have yet to be determined. A high index of suspicion should be used when attempting to make this diagnosis. This current concepts review presents the current thinking regarding pathophysiology, evaluation, and treatment of this condition.

Level of evidence: 5.

Keywords: Glenoid impingement; internal impingement; posterior impingement; throwing shoulder.

Figures

Figure 1.

Laxity changes in the dominant arm of the throwing shoulder demonstrate handedness or a lower more protracted shoulder compared to non dominant side.

Figure 2.

Glenohumeral internal rotation deficit as demonstrated by a significant lack of internal rotation on the dominant shoulder when compared to the non dominant shoulder.

Figure 3.

The Kibler scapular retraction test. In this test the scapula is stabilized on the posterior thoracic wall as the athlete elevates the shoulder demonstrating less symptomatic and improved shoulder elevation.

Figure 4.

Jobe's subluxation/relocation test. Posterior pain found upon overpressure to end range external rotation in the 90/90 position that is relieved with an posterior force would indicate posterior internal impingement.

Figure 5.

Sleeper stretch done in side lying to mobilize the posterior shoulder.

Figure 6.

Cross‐arm stretch done in supine with assistance from therapist.

Figure 7.

90/90 rhythmic stabilization exercises to increase strength and endurance of the rotator cuff muscles in a position that simulates throwing.

Figure 8.

Prone Blackburn exercises performed in 100 degrees of abduction and external rotation (thumb up).

Figure 9.

Prone on elbows serratus strengthening exercise for early scapular strengthening.

Figure 10.

Push up plus done with feet elevated to enhance cuff and scapular muscle recruitement.

Figure 11.

Punching type exercise for strengthening the upward rotation component of the serratus anterior.