Clinical Pearls is the newest SMR feature. Since much of current clinical practice is still based on anecdotal evidence, it is imperative for clinicians to incorporate both research and clinical experience when working with patients. Clinicians with decades of experience commonly have priceless advice to offer young professionals in clinical practice as well as research. Therefore, clinical pearls will allow the leading experts in Sports Medicine (orthopaedic surgeons, physicians, and other clinicians) to combine research and decades of clinical experience into a comprehensive discussion on a topic of expertise. This open forum will allow priceless insight into clinical sports medicine to be passed along and discussed. It is designed to bring the experts to you! I hope you enjoy Clinical Pearls and like always please provide feedback to help us better serve you.
Clinical Pearls: Tears of the Subscapularis Tendon
John D. Kelly IV, MD
University of Pennsylvania
Prior to the advent of rotator cuff arthroscopy partial tears of the subscapularis tendon were at undetectable amounts. Since rotator cuff arthroscopy, partial tears of the subscapularis tendon are becoming increasingly recognized with some studies reporting up to approximately a 40% prevalence upon shoulder arthroscopy. The old adage, ‘you may have not seen it, but it has seen you’ certainly applies here. There is an old proverb: ‘the eye sees what the mind knows’. Indeed, if subscapularis tear patterns are not appreciated, subtle tears will be missed.
The subscapularis is the largest rotator cuff tendon and it plays a large role in humeral head depression and shoulder stability. Since the subscapularis tendon rests anterior to the shoulder articulation, it confers appreciable protection against posterior instability – posterior humeral head translation applies considerable eccentric stress to the subscapularis tendon complex. Many clinicians are becoming increasingly aware of the potential implications of partial subscapularis injury due to the rise in clinical reports identifying combined partial supraspinatus and upper subscapularis tears.
Subscapularis tears usually originate proximally in the upper band and tend to propagate distally to the lower band. Tears may occur from traumatic external rotation or shoulder extension stresses. In addition attritional tears may occur secondary to subcoracoid impingement. Burkhart has posited the ‘roller wringer’ effect as a means of tendon attrition whereupon the tendinous portion of the upper subscapularis is pinched between the lesser tuberosity and the coracoid tip. A coraco-humeral interval of less than 6mm is considered stenotic.
Patients with tears of the subscapularis may complain of achey, anterior shoulder pain as well as weakness with abduction and internal rotation. Tucking one’s shirt in the back may be particularly troublesome as this requires coupled internal rotation and extension. Since the proximal biceps tendon derives medial stability from the subscapularis tendon insertion, biceps tendon symptoms may be present with a subscapularis tendon tear.
Examination findings include increased passive external rotation, especially in adduction, as well as loss of internal rotation strength. The ‘Belly Press’ test, whereupon the patient attempts to apply pressure to the abdomen while maintaining a straight wrist, has been shown to be reasonably sensitive for subscapularis tears (https://www.ncbi.nlm.nih.gov/pubmed/14564261).
The ‘Bear Hug’ test, first described by Burkhart et al. (https://www.ncbi.nlm.nih.gov/pubmed/17027405), has been shown by Chao and Thomas et al (https://www.ncbi.nlm.nih.gov/pubmed/18971057) to be perhaps the best test for detecting upper subscapularis tendon tears. To perform this maneuver, the examiner asks the patient to place the involved side hand on the contra lateral shoulder with the elbow in 45 degrees of forward flexion.
The subject then resists the tester’s attempts to pull the hand away from the shoulder. Normally, in the presence of a competent tendon, the subject will maintain the hand position on the shoulder despite the examiner’s efforts.
Partial and full thickness tears of the subscapularis should be repaired in active individuals. Arthroscopy affords superior visualization and mobilization. Even massive retracted tears can be safely liberated from adjacent scar and repaired back to the lesser tuberosity. A coracoidplasty should accompany repair in an effort to prevent tear recurrence. Finally, a medially subluxed biceps tendon should undergo tenodesis or tenotomy in order to protect the repair from undue stress.
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