Shoulder Pain

Charles De Mesa, DO, MPH

Brian A. Davis, MD, FACSM

Misty Humphries, MD, MAS, RPVI, FACS

FAST FACTS

Shoulder pain usually arises from the shoulder joint itself and can be due to bursitis, tendinopathy or tear, instability arthritis, or fractures.
It can be due to referred pain from the neck, thorax, or abdomen.
Shoulder pain may be divided into four categories: musculoskeletal, neurologic, vascular, and referred visceral-somatic pain.
A systematic approach is essential for effective management of shoulder pain.

INTRODUCTION

Shoulder pain is the third most common pain complaint in the primary care setting and accounts for approximately 16% of all musculoskeletal complaints.¹ The shoulder is a complex structure. Therefore, it is important to define the shoulder by region to better identify the location of perceived pain, as it may originate from somewhere else. This chapter will identify shoulder girdle pain as the perception of pain located within the bones which connects the arm to the axial skeleton on each side, namely, the clavicle, scapula, humerus and the joints, tendons ligaments, muscles, subcutaneous tissue, and skin subserving this location. Shoulder pain may be divided into four categories: musculoskeletal, neurologic, vascular, and referred visceral-somatic pain (see Tables 16-1, 16-2, 16-3, 16-4).²

In contrast, the “neck pain chapter” will identify neck pain as the region bounded superiorly by the superior nuchal line, laterally by the lateral margins of the neck, and inferiorly by an imaginary transverse line through the T1 spinous process.³

HISTORY

Physicians make a correct diagnosis about 80% of the time based on history and physical examination alone.⁴ The pain history requires a detailed interview which includes the chief complaint, mechanism of injury, accompanying symptoms, prior treatments, and impact on function and quality of life. The character, quality, and location of the pain including perceived level of pain are also important. Ways of conveying this information may include a numeric rating pain score with 0 being no pain and 10 being the worst possible pain. Ascertaining the pain score for current pain, average pain for the last week, lowest and worst pain in the last 24 hours allow for characterization of the pain leading up to the office visit. A pain diagram illustrating the location is useful in communicating the pattern of pain and for interval assessment following treatment.

MECHANISM OF INJURY

Acute versus chronic injuries are important considerations in the assessment of shoulder pain (Table 16-5). Trauma from a motor vehicle collision or accidental fall may imply acute pain while overuse or repetitive activities are indicative of chronic microtrauma leading to pain. It is important to identify the acute presentation of neuropathic pain as a result of trauma. For example, falls in the elderly may result in cervical extension injury leading to shoulder pain referred from the neck.

TABLE 16-1 Musculoskeletal Shoulder Pain¹^,²^,³^,⁴^,⁵^,⁶^,⁷^,⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²

DIAGNOSIS	PHYSICAL EXAMINATION	WORK-UP	TREATMENT	WHEN TO REFER
Rotator cuff tendinitis (RCT) with or without calcification	Shoulder external rotation (ER) usually weaker than internal rotation (IR) Hawkins-Kennedy test, the infraspinatus muscle test, and the painful arc sign Cervical spine examination to rule out spine pathology	X-rays (anterior-posterior [AP], axillary, and supraspinatus outlet) assess for alignment and degenerative changes Ultrasound (dynamic study to assess injury although operator dependent) MRI (magnetic resonance image) shoulder MR (magnetic resonance) arthrogram for clinical suspicion of a full thickness rotator cuff and/or a labral tear or postoperative complications	Activity modification, physical therapy (PT), analgesics, subacromial corticosteroid injection For calcifications: ultrasound-guided percutaneous lavage (UGPL) extracorporeal shock wave therapy	If refractory rotator cuff tendinitis with calcification, refer to physical medicine and rehabiliation, sports, or pain medicine for UGPL
RCT, partial	Shoulder ER usually weaker than IR Special tests: External rotation lag sign (ERLS), the dropping sign, the hornblower’s sign, and the internal rotation lag sign (IRLS) Cervical spine examination to rule out spine pathology	X-rays (AP, axillary, and supraspinatus outlet) assess for alignment and degenerative changes Ultrasound (dynamic although operator dependent) MRI shoulder MR arthrogram for clinical suspicion of a full thickness RCT and/or a labral tear or postoperative complications.	Activity modification, PT, analgesics, subacromial corticosteroid injection	No improvement after 3-6 mo of therapy, surgical consultation
RCT, complete	Shoulder ER usually weaker than IR Special tests: External rotation lag sign, the dropping sign, the hornblower’s sign, and IRLS Cervical spine examination to rule out spine pathology	X-ray Ultrasound MR arthrogram for clinical suspicion of a full thickness RCT and/or a labral tear or postoperative complications	Activity modification, PT, analgesics, surgery, (subacromial corticosteroid injection)	Acute, full thickness, with minimal amount of fatty infiltration—orthopedic surgical referral
Acromioclavicular (AC) joint arthritis	Painful palpation at AC joint Special tests: Horizontal cross arm adduction test localizes pain over the AC joint	X-ray AP and lateral Note: acromion morphology: Flat Curved Hooked AC joint morphology: Flat Curved Horizontal Hooked acromion and horizontal AC joints may have risk of developing localized impingement symptoms requiring surgery	PT, analgesics, acromioclavicular joint corticosteroid injection	If no improvement after 3-6 mo of therapy, analgesics and corticosteroid injection, then referral to orthopedic surgery for excision of the isolated painful joint or localized impingement region affecting functional quality of life
Glenohumeral arthritis	Local glenohumeral joint line tenderness and swelling anteriorly Reduced range of motion (ROM), external rotation, and abduction Atrophy of the rotator cuff muscles over the scapula Crepitation	X-ray AP and lateral external rotation, Y-outlet, and axillary views	PT, nonsteroidal anti-inflammatory drugs (NSAIDs), and occasionally intra-articular injection	Failure of conservative treatment, continued impairment in shoulder function affecting daily activities and associated with intractable pain should be referred to orthopedic surgery for prosthetic replacement (except in patients younger than 50 y in whom arthroscopic debridement and removal of osteophytes might be attempted to delay the need for prosthetic replacement)
Adhesive capsulitis	Stiffness, decreased ROM ER and abduction	X-ray (rule out other diagnoses) Ultrasound evaluation to rule out rotator cuff pathology MR arthrogram axillary recess may show thickening ≥1.3 cm	PT, occupational therapy (OT), gentle ROM exercises (e.g., pendulum swings) provided they do not cause undue discomfort As pain allows, patients can add stretching and strengthening exercises Intra-articular corticosteroid injection Ultrasound-guided intra-articular dilation (distension)	Refer to sports or pain medicine for intra-articular dilation For refractory adhesive capsulitis affecting function and quality of life, referral for arthroscopic surgical release (e.g. bipolar radiofrequency controlled capsular release)
Bicipital tenosynovitis	Painful palpation to the proximal aspect of the long head of the biceps (LHB), pain with activities that require eccentric deceleration of the upper extremity (such as throwing or swinging an object), and pain with muscular loading of the biceps (especially during shoulder flexion and arm supination)	X-ray (rules out fractures/dislocations) Ultrasound (dynamic diagnostic evaluation can exclude subluxation) MRI evaluation of the superior labral complex and biceps tendon	Analgesia with NSAIDs, acetaminophen (to avoid side effects from NSAIDs), ice, rest from overhead activity, or physical therapy. Biceps tendon sheath corticosteroid injection and/or needle tenotomy	Physical Medicine and Rehabilitation, sports referral for ultrasound-guided injections Orthopedic referral if no improvement after conservative measures for consideration of surgical debridement, tenodesis, or tenotomy
Biceps tendon tear	Tenderness with palpation over biceps groove worse with arm internally rotated 10 degrees “Popeye” deformity indicates rupture	Ultrasound: can show thickened tendon within bicipital groove MRI: can demonstrate thickening and tenosynovitis of proximal biceps tendon increased T2 signal around biceps tendon	Nonoperative NSAIDS PT steroid tendon sheath injections Operative arthroscopic tenodesis tenotomy	Referral for orthopedic surgery if no improvement after conservative therapy for evaluation of surgical debridement, tenodesis, or tenotomy
External impingement (with accompanying subacromial bursitis)	Shoulder ER usually weaker than IR. Hawkins-Kennedy test, the infraspinatus muscle test, and the painful arc sign Cervical spine examination to rule out spine pathology.	X-ray orthogonal views Ultrasound MRI shoulder	Activity modification, PT, and analgesic medications. Subacromial corticosteroid injection	Orthopedic surgical referral if no improvement after 3-6 mo of nonsurgical management
Internal impingement	Shoulder IR usually weaker than ER Muscular asymmetry with deep posterior pain with 90°-110° of abduction, slight extension, and maximal external rotation with scapula stabilized	X-ray orthogonal views Ultrasound MRI arthrogram to evaluate damage to the labrum or to assess capsular laxity and in those with prior surgery	Activity modification, PT and analgesic medications. Subacromial corticosteroid injection	Orthopedic surgical referral if no improvement after 3-6 mo of nonsurgical management
Proximal humerus fracture (PHF)	Inspection: ecchymosis of chest, arm, and forearm neurovascular examination: 45% incidence of nerve injury (axillary most common)	X-ray complete trauma series true AP scapular Y axillary CT scan to characterize injury and for preoperative planning	Majority of nondisplaced fractures are Neer one-part fractures. PHFs are considered nondisplaced if no segment is displaced more than 1 cm or angulated more than 45°	For complex fractures with significant displacement and/or if nerve injury is suspected, a surgical referral is indicated
Glenohumeral instability or dislocation	Shoulder IR usually weaker than ER Special attention to muscle tone, symmetry, and deformity. Passive ROM no more than 90° in any direction (risks redislocating) Apprehension and anterior release tests	X-ray shoulder, AP (external rotation), and scapula, lateral (Y view) MRI shoulder (if weakness persists after 4 wk of PT)	Pre- and postreduction X-rays to assess for humeral head location. Pre and post neurovascular examination. Sling immobilization following reduction (avoid NSAIDS may impair bony healing) PT/OT first 1-2 wk after dislocation, gentle ROM to minimize capsular contraction Reevaluation at 2 and 4 wk. If weakness persists at 4-wk, consider advanced imaging Restrictions for the first 4-6 wk include no abduction and ER at 90° to prevent redislocation Scapular strengthening introduced at 6-wk; continue strengthening dynamic/static stabilizers	Refer to surgery under following circumstances: >50% rotator cuff tear, glenoid osseous defect >25%, humeral head articular surface osseous defect >25%, PHF requiring surgery, irreducible dislocation, failed trial of rehabilitation, inability to tolerate shoulder restrictions, and inability to perform sport-specific drills without instability
Acromioclavicular separation	AC joint “step-off” on observation	X-ray AP bilateral for comparison and lateral additional projections include zanca view	Sling, cold packs, and medications can often help manage the pain.	Orthopedic surgical referral indicated for grade 3 Rockwood classification (AC and coracoclavicular [CC] ligaments are torn) with the CC distance is 25%-100% of the other side
Rheumatoid arthritis	Local glenohumeral joint line tenderness and swelling, atrophy, accompanying Metacarpophalangeal and proximal interphalangeal joint arthritis	Laboratory tests: erythrocyte sedimentation rate (ESR) C-reactive protein (CRP) rheumatoid factor (RF) anti-cyclic citrullinated peptide (CCP) antibodies antinuclear antibodies (ANA) Arthrocentesis: if there is diagnostic uncertainty	DMARD (e.g., methotrexate), NSAIDs, or glucocorticoids	Rheumatology referral to start DMARD therapy, prevent progressive joint injury and associated functional decline
Infectious (septic) arthritis	Monoarticular joint pain, swelling, warmth, and restricted movement	Synovial fluid aspiration performed (prior to administration of antibiotics); fluid should be sent for Gram stain and culture, leukocyte count with differential, and assessment for crystals.	Antimicrobial regimen based on coverage of the most likely organisms to cause infection More than 80% of septic arthritis cases are caused by S. aureus and other gram-positive organisms	Refer to infectious disease if poor response to therapy, coexistent renal or cardiac disease, and immunosuppression Surgical referral for refractory antibiotic treatment
Myofascial pain	Hyperirritable nodules within taut skeletal muscle bands when palpated produce a muscle twitch and reproduction of the patient’s referred pain	Laboratory tests: complete blood count (CBC), urinalysis renal and liver function, serum calcium, albumin, phosphate, TSH, CK, 25-hydroxyvitamin D Not routinely ordered but maybe helpful for myalgia.	Trigger point injections or dry needling (dry needling uses an acupuncture needle without introducing an injectate).	Consider referral to rheumatology if suspected polymyalgia rheumatica Consider physical medicine and rehabilitation referral for ongoing management