Shoulder Pain

HPI: 74yo F presents with 4 days of L anterior shoulder pain. She moved some boxes the day before the pain started but doesn't remember the time of onset. Pain is worse with any movement of the shoulder and unrelieved with tylenol or heat pad. No redness, rash, fever, pain in other joints, numbness or weakness besides limitation secondary to pain. No prior similar episodes, shoulder surgeries or diagnoses made related to the shoulder. Generally healthy, lives alone, takes care of self.

Physical Examination: No acute distress. Holding L arm in a position of comfort with shoulder adducted and internally rotated and elbow flexed. Radial pulse 2+. Median/ulnar/radial nerve distributions are motor intact and sensation intact to light touch. Normal strength compared to opposite extremity however effort is limited secondary to pain with shoulder flexion and adduction as well as elbow flexion. Tenderness present on anterior shoulder and anterior proximal third of humerus. No tenderness over scapula, elbow, wrist. No deformity, skin changes, or signs of infection. Compartments soft.

ED Shoulder Ultrasound?

The differential for shoulder pain is broad and includes rotator cuff tendinopathy, glenohumeral joint arthritis, AC joint pathology, biceps tendon pathology, and referred pain (ACS, gallbladder, cervical radiculopathy). Once other pathologies are ruled out, ultrasound is a great tool to evaluate the bones and muslces/tendons- the attributes that give the shoulder its mobility and expose it to injury also expose it to sound waves! The bones can be assessed for fractures, dislocations, post-reduction assessments, and AC and sternoclavicular joint spaces. The rotator cuff muscles/tendons as well as the biceps tendon can be imaged for tears or tendinosis, which are hypo- or anechoic regions in the muscle fibers. A tear can be full or partial thickness, and in general is more anechoic, well defined, and associated with bony irregularity (relative to the general swelling of tendinosis). Calcific tendinitis may show areas of hyperechoic calcium with shadowing. Focal areas of tendon discontinuity and loss of homogeneous hyperechoic architecture can indicate chronic tendinopathy and risk for rupture.

The long head of the biceps tendon is located in the biceps groove, bordered medially by the lesser tuberosity and laterally by the greater tuberosity.

How to perform: Have the patient sit with the palm up on the thigh to rotate the biceps groove anteriorly. The tendon can be assessed in both long and short axis, typically proximal to distal. The contralateral shoulder can be used for comparison. Supination and pronation of the forearm or internal and external rotation of the shoulder can reveal subluxation or dislocation of the tendon from the bicipital groove.

Biceps tendon probe placement:

Normal short axis biceps tendon view:

The long head of the biceps tendon fits snugly in the bony bicipital groove and shows a tightly packed hyperechoic, uniform pattern and is closely approximated to the bone.

Our patient:

Diagnosis: Biceps tendonitis

ltrasound findings of tendinitis: The hypoechoic area surrounding the long head of the biceps tendon represents significant edema. We do not see large hypoechoic areas within the tendon that would indicate a partial tear, and the fact that the tendon is present in the bicipital groove indicates there is not a proximal rupture and displacement.

Biceps tendon injuries include a spectrum of disorders including acute tendinitis (inflammation and swelling, more often in the young or middle aged) leading to chronic tenosynovitis (an inflammatory process distinct from the acute infectious variety). This may lead to degenerative tendinosis which is chronic degeneration from failed healing and repetitive trauma, typically in older patients. "Tendinopathy" is a more general term and may not include acute inflammation. Proximal biceps tendinopathy is more common than distal. There can also be subluxation or complete displacement of the tendon, as well as partial and complete tears. General shoulder pathology often coexists (impingement, labrum injuries, or rotator cuff tendinopathy or instability) which alters shoulder mechanics and contributes to proximal biceps stress and tedinopathy more often than a specific mechanism.

The pain of biceps tendinitis is typically located over the anterior, proximal shoulder and radiates distally over the biceps, worsened by activity and sometimes associated with a catching or snapping sensation.

Continued forceful biceps contraction can cause biceps tendinopathy to be complicated by biceps tendon rupture. Typically during activity, patients can feel a "pop" with swelling, decrease in muscle strength, "Popeye's deformity" (if the tear is complete), and pain. However, if there is a chronic painful tendinopathy, acute rupture can provide relief of pain.

Treatment:

Management of biceps tendinitis is conservative and includes rest, ice and compression. A sling can be used as needed during activity. Discuss the complication of frozen shoulder (adhesive capsulitis) from excessive sling use and recommend removing the sling when possible (at night, etc) with range of motion as tolerated. They should discuss physical therapy with their primary doctor. A short course of NSAIDs may be useful as well (consider topical for localized musculoskeletal pain).

For tendinopathy/tendinitis, patients should be electively referred to orthopedic surgery for possible steroid injection or MRI to look for partial tears or additional injuries in the rotator cuff or labrum. Distal biceps tendon rupture requires urgent referral to consider surgery because distal ruptures cause more functional limitation than proximal rupture. Surgery should be within a week to prevent contracture of the tendon- if this happens, the surgeon has to use the palmaris longus for a graft (and one out of five people don't have it!) Distal ruptures can be distinguished from proximal: they occur in ages <50, cause more weakness, pain is more localized to the elbow, the Popeye's sign is located higher (similar concept to the high-riding patella in a patellar tendon rupture vs quadriceps rupture), and the proximal tendon can be visualized in the correct location in the bicipital groove on ultrasound. Proximal ruptures are typically in the elderly, cause pain more localized to the shoulder, have a more distal Popeye's sign, and usually cause minimal functional limitation so treatment is usually conservative based on the patient's activity level, occupation, personal preference. The distinction between distal and proximal rupture can be difficult and ultrasound use is limited when visualizing the more distal biceps; so if you aren't sure where the rupture is, obtain an urgent referral.

Additional resources:

Chapter 15 Shoulder- Matthew Dawson and Mike Mallin. "Introduction to Bedside Ultrasound: Volume 1" Free iBook https://itunes.apple.com/us/book/introduction-to-bedside-ultrasound-volume-1/id554196012?mt=11

European Society of MSK Radiology: Shoulder Ultrasound pdf https://essr.org/content-essr/uploads/2016/10/shoulder.pdf (thanks for the source, Ryan Freedman!)

Sonosite shoulder ultrasound video: https://www.youtube.com/watch?v=QelYPkMLAOk

-Dan Deweert MD