Injuries to the rotator cuff (RC) range from simple contusions and tendonitis to chronic tendinopathy, partial tears, and full-thickness tears (PTTs versus FTTs). RC pathology can affect any subset of patient populations, from the casual “weekend warrior” to elite-level professional athletes. Similarly, RC pathology is seen across all ages. 
While subacromial impingement syndrome (SIS) is the most common cause of shoulder pain, rotator cuff (RC) tendonitis is often seen in association with shoulder impingement. RC tendonitis can present in the acute setting following injury or, chronically, as a result of repetitive overuse activities or sport-related demands .
Acute Rotator Cuff Tendonitis
Acutely, RC tendonitis afflicts athletes at all levels of competition. Acute injuries often occur secondary to direct trauma to the shoulder in contact sports, poor throwing mechanics in overhead sports (i.e., baseball, javelin throwers), or from falls on an outstretched arm.
Chronic Rotator Cuff Tendinopathy
Chronically, RC tendinopathy can occur secondary to a variety of proposed mechanisms:
The extrinsic theory of mechanical impingement and pathologic contact between the undersurface of the acromion and the RC results in repetitive injury to the cuff. RC tendinopathy results in weakened areas of the cuff, eventually resulting in PTTs and/or FTTs. The mechanical compression can occur secondary to a degenerative bursa, acromial spurring, and predisposing acromial morphologies (i.e., the hooked-type acromion). Theories were popularized and modified by Watson-Jones, Neer, and Bigliani.
Several theories exist to support intrinsic degeneration of the cuff as the primary source of shoulder impingement. In general, the intrinsic degenerative theories cite that cuff degeneration eventually compromises the overall stability of the glenohumeral joint. Once compromised, the humeral head migrates superiorly, and the subacromial space decreases in size. Thus, the cuff becomes susceptible to secondary extrinsic compressive forces, ultimately leading to cuff degeneration, tendinopathy, and tearing.
Shoulder pain comprises the third-leading musculoskeletal complaint at physician office visits. Following spine and knee complaints, shoulder complaints account for 4.5 million visits and $3 billion in associated healthcare costs in the United States alone. With a lifetime prevalence rate of 67%, shoulder pain is most commonly caused by SIS and/or RC pathologies. Rotator cuff (RC) injuries afflict patient populations in an age-dependent fashion. Prevalence rates increase from 5% to 10% in patients younger than 20 years of age to over 60% in patients over age 80 years old.
Acute rotator cuff (RC) tendonitis can occur secondary to direct blows to the shoulder, poor throwing mechanics in overhead sports, or from falls on an outstretched arm.
Tendinopathy ensues after repetitive RC injury triggers a recurrent pathological cycle that results in acute on chronic tendonitis, increasing levels of tendinopathy and tendinosis, and ultimately, PTTs and/or FTTs to varying degrees of tear sizes and retraction. The exact pathogenesis of RC tears remains controversial, but most clinicians agree the underlying mechanism is comprised of a combination of extrinsic impingement from structures surrounding the cuff and intrinsic degeneration from changes within the tendon itself.
A comprehensive history should be obtained by clinicians evaluating patients with acute or chronic shoulder pain. Characteristics of a history of potential rotator cuff (RC) injury include:
A thorough history includes current or history of sports participation (as well as specific positions played in each sport), occupational history and current status of employment, hand dominance, any history of injury/trauma to the shoulder(s) and/or neck, and any relevant surgical history.
Physical Examination Pearls
Coexisting cervical radiculopathy should be ruled out in any situation where neck and/or shoulder pathology is in consideration. Observation of neck posturing, muscular symmetry, palpable tenderness, and active/passive ROM should be evaluated. Special tests that are helpful in this regard include the Spurling maneuver, myelopathic testing, reflex testing, and a comprehensive neurovascular exam.
Clinicians must observe the overall shoulder girdle for assessment of symmetry, shoulder posturing, and overall muscle bulk and symmetry. Scapular winging should also be ruled out. The skin should be observed for the presence of any previous surgical incisions, lacerations, scars, erythema, or induration.
After the observational component of the physical examination, the shoulder should be palpated for any areas of tenderness. Classically, RC tendonitis correlates with anterolateral tenderness to palpation. Next, the active and passive ROM of both shoulders is documented. In cases of RC tendonitis, patients may demonstrate compromised active ROM but should exhibit full passive ROM. In the absence of advanced degenerative changes affecting the glenohumeral joint, limited passive ROM is considered diagnostic for adhesive capsulitis and involves a separate treatment algorithm from RC tendinopathy/impingement.
The clinician can assess motor strength grading for C5 to T1 nerve roots in addition to specific RC muscle strength testing. Specifically, RC strength and/or pathology can be determined via the following examinations:
1. Supraspinatus (SS)
2. Infraspinatus (IS)
3. Teres Minor (TM)
4. Subscapularis (SubSc)
5. External impingement/SIS
6. Internal impingement
Radiographic imaging should be obtained in all patients with acute or chronic shoulder pain.
Recommended imaging includes a true anteroposterior (AP) image of the glenohumeral joint (i.e., the “Grashey” view). The true AP image is taken with the patient rotated between 30 and 45 degrees offset the cassette in the coronal plane. Alternatively, the beam can be rotated while the patient remains neutral in the coronal plane. The distance between the acromion and the humeral head (i.e., the acromiohumeral interval) can be calculated. A normal interval is between 7 and 14 mm, and this interval is decreased in cases of advanced degenerative arthritis and RCA.
Other radiographic imaging includes a 30-degree caudal tilt view that can be performed to visualize the presence of acromial spurring. In addition, the “scapular Y” or “supraspinatus outlet” view is used to determine acromial morphology.
The following are the most common radiographic changes associated with rotator cuff (RC) pathology:
Ultrasound (US) is an often-underutilized imaging modality to detect RC tendon and muscle belly integrity. In 2011, a meta-analysis of over 6,000 shoulders revealed a sensitivity of 0.96 and specificity of 0.93 in assessing shoulders for PTTs or FTTs.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is useful in evaluating the overall degree of RC pathology. MRI can be helpful in providing more accurate cuff tear details, including partial- versus full-thickness tears, the extent and size of the tear(s), location, and degree of retraction. In cases of chronic RC pathology, the cuff can be assessed for fatty degenerative changes on the T1-weighted sagittal sequence series.
Subdeltoid and/or subacromial bursitis can also be evident and are important considerations as potential sources of pain. In addition, the acromioclavicular (AC) joint, acromial morphology, and long head of the biceps (LHB) tendon integrity are better appreciated. A systematic approach to reviewing shoulder MRIs is important, especially when correlating the MRI findings with the patient-reported symptoms and clinical examination.
Given the complex nature of rotator cuff (RC) tendonitis, we recommend the treatment and management be broken down into the following categories:
Group 1: Partial-Thickness (PTT) or Full-Thickness RC Tears (FTTs), Asymptomatic Patient 
Patients presenting with MRI-evidence of PTTs or FTTs often present without any symptoms. The most recent American Academy of Orthopaedic Surgeons (AAOS) clinical practice guideline (CPG) summary reported the growing awareness of incidental RC pathology revealed via shoulder MRIs in asymptomatic patient populations. Although there is evidence of increasing prevalence of RC disease in the aging population, there is no reliable evidence that surgical intervention prevents tear propagation or the development of clinical symptoms. Thus, the committee recommended symptomatic management via nonoperative modalities alone.
Patients presenting with symptoms of EI/SIS in the absence of FTTs are first managed with nonoperative treatment modalities. There is no agreed upon time interval when it is most appropriate to proceed with surgical intervention in this particular group of patients. The literature ranges from 3 months to 18 months. Surgical intervention should be individually tailored based on the patient’s symptoms, improvement with nonoperative modalities, and overall goals of the patient.
Group 3: Chronic RC Tears, Symptomatic Patients
The AAOS CPG reported a “weak” recommendation grade secondary to limited available evidence in the literature comparing rotator cuff repair (RCR) to continued nonoperative treatment modalities in this subset of patients. Certainly, the overall clinical picture must be considered, and the treatment tailored to the individual patient in each scenario.
Physical therapy (PT)
RCS surgical techniques range from debridement, subacromial decompression (SAD), and/or acromioplasty to RC debridement and, when indicated, RC bursal- or articular-sided tear completion with RCR. The latter will not be discussed in this review. Assuming no RC FTTs are present, the extent of surgical management for external impingement/SIS alone includes:
The differential diagnosis for chronic shoulder pain includes several etiologies:
Rotator Cuff (RC) Pathology
AC Joint Conditions
The majority of patients with rotator cuff (RC) tendinopathy in the absence of FTTs improve with nonoperative management. The most recent AAOS CPGs touted a “moderate” recommendation grade for initial treatment of NSAIDs and/or exercises programs based on multiple level II studies in the literature.
Complications associated with rotator cuff syndrome (RCS) are best broken down into nonoperative- versus operative-related complications:
Following SAD/acromioplasty (without RCR), patients are kept in a sling for 1 to 2 weeks with early passive ROM rehabilitation parameters. Clinicians should recognize the risk of overutilization of sling immobilization, especially when soft tissue repair protocols do not have to be respected.
Initially, patients are instructed to avoid heavy lifting and exercises to facilitate soft tissue healing. Cryotherapy devices are often applied for the first 10 to 14 days postoperatively. Physical therapy is often started postoperatively once the sling is discontinued.
Full active ROM should be achieved by 3 to 6 weeks maximum. If applicable, return to sport-specific skills at 6 to 8 weeks as tolerated.
Primary care medical doctors can manage the majority of rotator cuff syndrome (RCS) cases, especially along the nonoperative management spectrum. After these modalities are exhausted, an appropriate referral can be made to an orthopedic surgeon. While the nonoperative management is not conclusively managed with a supervised physical therapy protocol, a supervised protocol is recommended in the postoperative setting to regain maximum ROM and full strength.
Patients should be educated about the condition as well as the possibility of continued chronic pain following surgical management for persistent impingement/rotator cuff (RC) tendonitis symptoms.
Rotator cuff (RC) tendonitis is a clinical entity consisting of a wide range of clinical symptoms ranging in severity from mild shoulder impingement and can advance in the long-term setting to progressive partial-thickness cuff tears (PTTs) and/or full-thickness cuff tears (FTTs). Evaluation and treatment are best with an interprofessional team. Primary care providers, radiologists, and physical therapists are often involved. Consultation with sports medicine providers, orthopedists, and physiatrists may be needed. Orthopedic nurses provide education, monitor response, and document findings for the team.
When clinicians are working up acute or chronic shoulder pain, it is imperative to correlate the clinical examination with radiographic imaging, MRI, and response to nonoperative treatment modalities. The latter consists of physical therapy, NSAIDs, rest/activity modification, and injections. Surgical management is considered after impingement symptoms fail to resolve or worsen after all other management modalities are exhausted. Referral to an orthopedic surgeon should be considered, especially with long-standing persistent symptoms. After surgery, enrollment in a physical therapy program to regain joint mobility and muscle strength are highly recommended. With proper treatment, the outcomes for most patients are good.  [Level 5]
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