CASE REPORT: Chiropractic management of posterior shoulder capsule tear.
Peter Zilahy DC
KEYWORDS:Shoulder capsule, posterior joint capsule, capsular tear, teres minor tendon, infraspinatus tendon, myotendinous junction
Posterior joint capsule injury is a rare condition that represents approximately 10% of shoulder instability. The posterior shoulder instability is between 2%-5% of all shoulder dislocations. Anterior laxity or dislocation is much more common and is well-recognized in the orthopedic and physical therapy
The shoulder joint provides great ranges of motion with daily activities because of its position within the glenoid cavity. There is a complex and well-balanced interplay between the scapula, clavicle, and humerus controlled by the surrounding soft tissues, including the supraspinatus, infraspinatus, subscapularis teres major, teres minor, along with the shoulder capsule, ligamentous, and labral stabilizers.
Posterior capsule injury and instability is frequently misdiagnosed due to the lack of awareness and experience of the treating physician.
The mechanism of injury occurs with force applied to the shoulder when it is in 90° forward elevation, adduction, and internal rotation of the humerus[3-5].
Clinical presentation is with intense discomfort and an inability to mobilize the shoulder joint. This may be related to excessive stretching of the muscles or the joint capsule during the dislocation itself.
A very athletic 26-year-old gentleman was the belted driver of an SUV, moving at a moderate rate of speed, looking straight forward, wearing seatbelts with the shoulder harness, his left hand at the 2 o'clock position, when the vehicle was struck on the left by a sedan. The force vector resulted in impact of his left shoulder against the driver's side door; he stated that he "left his shoulder imprint into the door." The patient reports" that it feels like his shoulder goes out of place."
The patient is unable to abduct his left shoulder greater than 20°. Active ranges of motion of the left shoulder with his arm adducted: external rotation 20°, flexion 80°, extension 35°, abduction 20°. With the arm abducted, passive internal rotation 30°, external rotation 0°. Passive rotation is serely limited by pain with the arm abducted and flexed. Jerk test was performed with the patient sitting, arm flexed to 90° and internally rotated with axial loading and horizontal adduction resulting in pain. Kim test was performed with the patient sitting, the arm abducted to 90°, I then elevated the arm approximately 45° while applying postero-inferior force to the upper arm and axial load to the elbow resulting in pain. Positive Hawkins Maneuver, negative Speeds Test. Increased sensitivity to the insertion of the subscapularis into the lesser humeral tubercle and the teres minor insertion to the greater tubercle. Exquisite sensitivity in the muscle belly of the teres minor and posterior capsular region.
MRI LEFT SHOULDER:
This is the reading radiologic report:
"HISTORY: NECK PAIN, LEFT SHOULDER PAIN COMPARISON: None.
TECHNIQUE: Multiplanar images of the left shoulder were obtained at 3.0 Tesla without IV contrast..
FINDINGS:AC JOINT: The acromioclavicular joint appears normal. There is no significant narrowing of the subacromial space. There is no significant fluid within the subacromial/subdeltoid bursa.
ROTATOR CUFF TENDONS:
Supraspinatus: The supraspinatus tendon appears normal.
Infraspinatus: The infraspinatus tendon appears normal.
Subscapularis: The subscapularis tendon appears normal. There is mild edema of the subscapularis muscle near the musculotendinous junction consistent with mild partial muscle tear.
Teres Minor: The teres minor tendon appears normal. There is mild edema of the teres minor muscle near the musculotendinous junction consistent with a partial muscle tear.
GLENOHUMERAL JOINT: The glenohumeral joint appears normal.
BICEPS TENDON: The biceps tendon attachment is intact.
LABRUM: The glenoid labrum appears intact.
IMPRESSION: No rotator cuff tendon or labral tear. Edema within the teres minor and subscapularis muscles consistent with mild partial muscle tears."
I reviewed each image and was concerned about the questionable high signal in the BLADE SEQUENCE. Consequently, after being trained by Dr Kevin Baker a Fellow in MSK radiology, I contacted him, and we reviewed the series together. Dr Baker clearly identified the posterior capsular tear as reported below.
Image #1 is a PROTON DENSITY BLADE FS AXIAL view. Image #2 is a BLADE T2 FS SAGITTAL view with the reference line through the posterior capsular tear.The RED ARROWS point to the brighter signal (representing a fluid-like signal consistent with inflammation).
Image #3, the BOLD BLUE ARROW points to the insertion of the posterior capsule into the scapula. The SMALL BLUE ARROWSoutline the continuation of the joint capsule, which is the smooth dark line. The RED ARROW indicates the capsular tear as noted by the bright signal. TheAMBER ARROWSpoint to an increased signal as a result of synovial fluid leaking between the joint capsule and muscle. The GREEN ARROWpoints to the intact teres minor tendon into the greater tubercle of the humerus.
#4 is one slice inferior to #3 image. THE RED ARROWpoints to increase signal indicating fluid and clear separation of the joint capsule. THE BLUE ARROWnotes the retraction of the capsular tissue, the AMBER ARROWSoutline the synovial fluid that has leaked into the junction between the capsule and muscle.
The patient's initial treatment was focused on reducing pain and inflammation. Treatment included 810 nm continuous wave laser, acupuncture, myofascial release of the teres minor and pain free ranges of motion movements. Home therapy included alternating between ice and heat as well as exercises in pain-free ranges. The patient was referred to an orthopedic surgeon and to physical therapy, with a special focus on perturbation maneuvers exercises in an attempt to stabilize the shoulder.