16.1 Shoulder Complex: Rotator Cuff Tears, Impingement, and Frozen Shoulder
Key Takeaways
Historical acromial types describe shape. During late cocking, the articular cuff can contact the posterosuperior glenoid. Interpret both findings with symptoms and the examination.
Park’s full-thickness tear combination was painful arc, drop arm and infraspinatus strength testing. The broader subacromial combination used Hawkins–Kennedy in place of drop arm.
Record pain and weakness separately on cuff strength tests. A painful arc, lag sign or change with scapular assistance contributes to the examination.
Assess active and passive motion in suspected adhesive capsulitis. Use pain, stiffness and the response to testing to guide dosage and progression.
Measure internal and external rotation bilaterally and calculate each total arc. Use the findings with symptoms, exposure and the throwing task.
Shoulder Complex: Rotator Cuff Tears, Impingement, and Frozen Shoulder
Assess active and passive shoulder motion, strength, symptoms and the demands of the patient's activity. The relative contributions of pain, stiffness and weakness help determine the next examination or treatment step.
Shoulder Biomechanics and Kinematic Couples
The shoulder complex includes the glenohumeral, acromioclavicular and sternoclavicular synovial joints and the functional scapulothoracic articulation. During elevation, humeral motion combines with scapular upward rotation and other scapular and clavicular movements. The traditional 2:1 glenohumeral-to-scapulothoracic ratio is an approximation. Relative contributions vary by plane, elevation range and individual.
Dynamic Control During Elevation
- The deltoid contributes to elevation and can produce a superior shear component. Rotator cuff muscles compress the humeral head against the glenoid and can oppose excess superior translation. The contribution of each muscle changes with arm position.
- Serratus anterior and the trapezius contribute to scapular upward rotation and posterior tilt. Consider the phase and plane of elevation and how a change in movement affects symptoms and function before interpreting a scapular finding.
Rotator Cuff-Related Shoulder Pain and Internal Impingement
Pain with active elevation or resisted cuff loading can occur with rotator cuff tendinopathy, partial tears or other shoulder disorders. History and examination guide the initial management. Consider the cervical spine and other sources of referred pain when the pattern warrants it. New weakness or inability to elevate the arm after trauma warrants prompt assessment for a significant tear or another acute injury.
Historical acromial and subacromial descriptions
Bigliani types I, II and III describe flat, curved and hooked acromial profiles, respectively. An acquired spur can alter the profile seen on imaging. Record the observed shape without using it alone to diagnose the source of pain. Neer's historical stages described edema and hemorrhage, then fibrosis and tendinopathy, then changes such as spurs and cuff tears. Age and radiographic shape cannot determine the stage or the treatment for an individual patient. In the FIMPACT trial, arthroscopic subacromial decompression offered no benefit over placebo surgery for subacromial pain at ten years.
Internal posterosuperior impingement and throwing motion
During late cocking, the abducted, externally rotated humerus can bring the articular side of the posterior cuff into contact with the posterosuperior glenoid and labrum. Posterior pain at that point in throwing warrants assessment of cuff and labral symptoms, instability, rotational motion and training load. Contact alone cannot establish the cause of pain.
Measure passive internal and external rotation at the same abduction angle on both sides, commonly 90°, with consistent scapular stabilization. Glenohumeral internal rotation deficit (GIRD) describes a side-to-side reduction in internal rotation of the throwing shoulder. Wilk's 2011 professional pitcher study defined GIRD as an internal rotation difference of at least 20°. A total rotation deficit greater than 5° was a separate measure associated with a higher injury rate in that cohort. Internal rotation asymmetry alone did not significantly distinguish injured and uninjured pitchers. Throwing-related osseous and soft-tissue adaptation can both affect motion.
Tip
Calculate the total arc by adding internal and external rotation for each shoulder. Similar arcs with different internal rotation values can occur when external rotation compensates. In a symptomatic athlete, examine the painful task, load history, strength and motion before deciding what to change.
Tear description and examination
| Test | How to use the finding |
|---|---|
| Neer and Hawkins–Kennedy | With the shoulder supported, test symptom reproduction with passive elevation or with gentle internal rotation at about 90° of forward flexion, respectively. Familiar pain can support a cuff-related pain hypothesis in context. |
| Painful arc | Note familiar pain during active elevation and where it eases. A painful midarc supports the symptom pattern without identifying a particular tendon. |
| Empty can and full can | Apply resistance in scapular-plane elevation with the thumb down or up, respectively. Document pain and weakness separately. Use a position the patient can tolerate. |
| Drop arm and external rotation lag | After the arm is placed in position, observe control on lowering or the ability to hold external rotation. Failure can raise concern for a substantial cuff deficit. A negative finding cannot exclude a tear. |
| Hornblower sign | Difficulty maintaining external rotation with the arm elevated can indicate posterior cuff dysfunction. Consider the available range, pain and other strength findings. |
| Lift-off, belly press and internal rotation lag | These maneuvers assess internal rotation function when subscapularis involvement is suspected. Use belly press if the patient cannot safely reach behind the back. Observe compensations and compare with other findings. |
Park and colleagues tested two distinct combinations. In their study, all three positive findings in the broad subacromial group gave a post-test probability of 95%. The different combination for full-thickness cuff tears gave 91%. These values reflect the study population and methods.
For suspected atraumatic cuff tendinopathy, the 2025 clinical practice guideline supports education, activity adjustment and progressive active rehabilitation. For example, an overhead worker can temporarily reduce repetitive end-range loading and use tolerated external rotation and elevation exercises to build capacity. Track how the worker tolerates the actual task as the load increases. A substantial or persistent deficit may require imaging or specialist review.
Adhesive Capsulitis (Frozen Shoulder)
Adhesive capsulitis commonly involves gradual loss of both active and passive motion, with passive external rotation often particularly restricted. Capsular inflammation and fibrosis can involve the rotator interval and axillary recess. Consider trauma, surgery or a systemic association such as diabetes. Assess for alternative explanations, including glenohumeral arthritis when the clinical pattern warrants imaging or referral.
Freezing, frozen and thawing describe the broad course from painful restriction through stiffness toward improving motion. Phases overlap, their duration varies and residual symptoms are possible. Choose exercise and mobilization from the patient's current irritability and response.
| Irritability | Findings that guide initial care | Examples |
|---|---|---|
| High | Rest or night pain, with pain appearing well before passive resistance | Education, comfortable active-assisted movement and a trial of low-grade mobilization |
| Moderate | Pain around the point of resistance, with symptoms more predictable during movement | Gradually increase active motion and use tolerable mobilization or stretching |
| Low | Stiffness limits movement before substantial pain | Progress end-range mobilization, stretching, strength and task practice as tolerated |
Discuss medical review for a glenohumeral corticosteroid injection when appropriate, particularly when pain limits sleep and function. Benefits are mainly short term. In a patient with diabetes, coordinate with the medical team about blood glucose management and suitability for injection.
Joint Mobilization and Reassessment
The simple convex–concave model suggests assessing anterior glide for external rotation and inferior glide for abduction. In a small randomized adhesive capsulitis trial, posterior glenohumeral glide produced more improvement in external rotation than anterior glide. Assess the person's irritability, select a tolerable technique and recheck range or a relevant task. The study compared motion outcomes and did not establish a required direction or a single tissue mechanism.
Scapular Motion and Symptom Modification
Kibler's visual classification describes the appearance of the scapula during movement. A pattern can guide examination and exercise selection. It cannot identify a specific weak muscle or nerve lesion by itself.
- Scapular retraction test: Compare resisted elevation with and without manual stabilization of the scapula in retraction. Record a change in force or pain.
- Scapular assistance test: Compare active elevation with and without manual assistance into upward rotation and posterior tilt. A change in pain or available motion can help select a task modification or exercise.
- Persistent winging or weakness: Test the relevant muscles and consider cervical, brachial plexus and peripheral nerve causes. Localize suspected nerve involvement from the broader neurologic examination.
Total shoulder arthroplasty in Saudi practice
The Saudi MOH 2025 total shoulder arthroplasty protocol starts with protection and gradual passive shoulder motion within the prescribed limits. The immediate phase restricts active shoulder motion, lifting and support of body weight through the hand, while allowing active motion of the elbow, wrist and hand. Confirm the exact operation and surgeon's restrictions, especially before progressing rotation, active elevation or loading. Use both time and clinical criteria for progression. A rotator cuff repair follows its own tissue-protection plan.
Clinical Case Scenario: Shoulder Complex
A 56-year-old female high school biology teacher with a 6-year history of type 2 diabetes mellitus presents with worsening left shoulder pain and stiffness over the past 5 months. She reports intense aching at night that wakes her from sleep whenever she turns onto her left side. She has severe difficulty fastening her bra behind her back and reaching overhead into classroom cupboards.
Active and passive movement are limited in multiple planes. Passive external rotation is 18° on the left versus 75° on the right, and abduction is 78° versus 170°. She can reach the sacrum with the left hand and T8 with the right. Active elevation elicits an early shrug. Pain is 8/10 and appears well before passive resistance in external rotation.
- Working diagnosis: Marked passive restriction, particularly in external rotation, supports adhesive capsulitis after other causes are considered. Night pain and pain before resistance indicate high irritability. Diabetes is relevant to the history and treatment discussion.
- Initial care: Choose comfortable assisted movement and activity adjustments, and consider low-grade mobilization if it eases symptoms. Discuss medical review for injection and glucose monitoring. Reassess sleep, external rotation and reaching before progressing end-range work.
An outlet radiograph shows a hooked acromial profile in a worker with shoulder pain. How should the physiotherapist interpret this observation?
It describes a Bigliani type III profile. Evaluate the pain and functional findings before selecting treatment.
It describes a Bigliani type I profile and confirms a full-thickness cuff tear.
It describes a Bigliani type II profile and confirms posterosuperior internal impingement.
It establishes that subacromial decompression is indicated.
A 54-year-old female with poorly controlled type 2 diabetes mellitus is referred to physical therapy with a 3-month history of progressive left shoulder pain. She reports severe nocturnal pain (8/10 on VAS) and difficulty sleeping. Examination reveals passive external rotation restricted to 15°, abduction restricted to 70°, and pain occurring well before the onset of tissue resistance. Based on the Kelley et al. clinical practice guidelines for adhesive capsulitis, what is the most appropriate initial management strategy?
Start with Grade IV mobilizations and prolonged end-range stretching despite severe pain and guarding.
Implement low-grade (Maitland Grade I–II) oscillatory mobilizations, pain-free active-assisted ROM, patient education, and consider physician referral for an intra-articular corticosteroid injection
Perform aggressive plyometric overhead medicine ball tosses and heavy eccentric loading of the rotator cuff to prevent disuse atrophy
Immobilize the shoulder in a neutral abduction sling for 4 weeks and prohibit all active or passive movements until resting pain resolves
Which three findings formed the best-performing combination for a full-thickness rotator cuff tear in the Park et al. 2005 study?
Hawkins–Kennedy, painful arc and the infraspinatus muscle strength test
Painful arc, empty can and the external rotation lag sign
Painful arc, drop-arm sign and the infraspinatus muscle strength test
Drop-arm sign, Hawkins–Kennedy and the lift-off test
A collegiate baseball pitcher presents with posterior shoulder pain during the late cocking phase of throwing. Bilateral goniometric assessment of glenohumeral passive range of motion at 90° of abduction reveals the following: Throwing shoulder ER = 125°, IR = 30° (Total Arc = 155°); Non-throwing shoulder ER = 105°, IR = 52° (Total Arc = 157°). How should the physical therapist classify these findings and direct rehabilitation?
Normal physiologic throwing adaptation with symmetric total arc; no interventions targeting posterior shoulder tightness are needed
Anterior shoulder instability requiring an immediate shoulder immobilization brace and absolute cessation of throwing for 6 months
Severe multi-directional glenohumeral instability requiring surgical stabilization of the inferior glenohumeral ligament complex
The throwing shoulder has 22° less internal rotation with a 2° total arc difference. Interpret these findings with the symptomatic throwing assessment before selecting treatment.
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