Rotator cuff tendinopathy is a chronic pathology of rotator cuff tendons (especially supraspinatus) characterized by degenerative thickening, signal change, and function loss. Unlike tear, tendon continuity is maintained but tendon structure is disrupted. It is one of the most common components of subacromial impingement syndrome. On MRI, tendon is thickened with intermediate T2 signal increase but no fluid-filled tear cleft. Treatment is generally conservative — physiotherapy, subacromial injection, activity modification.
Age Range
35-70
Peak Age
45
Gender
Equal
Prevalence
Very Common
The pathophysiology of rotator cuff tendinopathy combines chronic mechanical compression (subacromial impingement) and intrinsic tendon degeneration. The critical zone of supraspinatus tendon (~1 cm proximal to insertion) is a vascular watershed region predisposed to hypoxic degeneration. Chronic impingement and repetitive microtrauma cause collagen Type I degeneration, mucoid changes, and neovascularization in tendon matrix — this histopathological process is termed 'tendinosis' (inflammation minimal, degeneration dominant). The pathophysiological basis of intermediate T2 signal in tendinopathy on MRI is mucoid changes and collagen disorganization in tendon matrix. In normal tendon, tightly packed collagen fibers produce very low signal with ultra-short T2 (~1-5 ms). In tendinopathy, disruption of collagen fiber organization and mucoid material accumulation (proteoglycan + water) lengthens T2 relaxation time — but not as long as free water, creating intermediate signal. This is the signal level between fluid-filled tear (very bright T2) and normal tendon (very low T2).
On T2 fat-sat MRI, supraspinatus tendon appearing thicker than normal with intermediate signal increase but no fluid-filled tear cleft. This triad is the most important MRI finding differentiating tendinopathy from tear. Absence of fluid cleft indicates tendon continuity is maintained, intermediate signal reflects degenerative matrix changes.
On T2 fat-sat coronal images, supraspinatus tendon is thicker than normal (>8 mm) with intermediate signal increase. Tendon continuity is maintained — no fluid-filled cleft at articular or bursal surface. This finding is the MRI correlate of degenerative tendinopathy. Signal increase may be homogeneous or heterogeneous.
Report Sentence
The supraspinatus tendon is thickened with intermediate signal increase; tendon continuity is maintained consistent with tendinopathy.
On T2 fat-sat sagittal and coronal images, subacromial impingement findings are seen: acromial undersurface irregularity or hook (Type III), coracoacromial ligament thickening, subacromial space narrowing (<7 mm), AC joint osteoarthritis and osteophytes. These findings reflect extrinsic causes of tendinopathy.
Report Sentence
Type III hooked acromion and subacromial space narrowing are seen, consistent with subacromial impingement syndrome.
On US, supraspinatus tendon thickening (>8 mm) and hypoechoic change is seen. Neovascularization (new vessel formation) within tendon may be detected on power Doppler — this is a finding of active tendinopathy. Loss of tendon fibrillar structure and heterogeneous echo pattern reflects degeneration.
Report Sentence
On US, supraspinatus tendon is thickened and hypoechoic with neovascularization on power Doppler; consistent with active tendinopathy.
On T1-weighted sequences, tendinopathy tendon shows normal low signal — no fatty infiltration or muscle atrophy. Combination of T1 low signal and T2 intermediate signal is typical for tendinopathy and used for differentiation from tear. Muscles show normal volume and signal.
Report Sentence
Normal signal in supraspinatus tendon and muscle on T1 sequences with no fatty infiltration detected.
On coronal PD sequences, heterogeneous signal in supraspinatus tendon is seen — focal or diffuse intermediate signal areas but articular and bursal surfaces are smooth and intact. Should not be confused with magic angle artifact — artifactual signal increase may occur at 55 degrees and should be re-evaluated at different TE.
Report Sentence
Heterogeneous signal in the supraspinatus tendon with preserved surface integrity is seen; consistent with tendinopathy (magic angle artifact excluded).
Criteria
Edematous tendon, peritendinous fluid, clinically acute pain
Distinct Features
Usually after acute overuse, responds to anti-inflammatory treatment
Criteria
Thickened tendon, mucoid degeneration, neovascularization, minimal inflammation
Distinct Features
Prolonged symptoms, partial response to conservative treatment, risk of progression to tear
Distinguishing Feature
In tear tendon continuity is lost with fluid-filled gap; in tendinopathy tendon is thickened but continuity maintained, no fluid cleft
Distinguishing Feature
In calcific tendinitis low-signal calcification focus within tendon with surrounding reactive edema; no calcification in tendinopathy
Distinguishing Feature
In bursitis primary pathology is bursal fluid accumulation, tendon may be intact; in tendinopathy primary pathology is tendon structure change
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
6-monthRotator cuff tendinopathy treatment follows a stepwise conservative approach with 70-80% recovery in 3-6 months. First step (first 6 weeks): NSAIDs (ibuprofen, naproxen — 2-4 weeks), ice, activity modification (avoid painful positions — especially overhead movements), physiotherapy (rotator cuff strengthening — especially supraspinatus and infraspinatus eccentric strengthening, scapular stabilization — serratus anterior and lower trapezius strengthening). Second step (6 weeks-3 months): US-guided subacromial corticosteroid injection (diagnostic and therapeutic — 60-70% short-term pain relief but repeated injections may accelerate tendon degeneration — maximum 3 injections recommended), intensified physical therapy. Third step (3-6 months non-responsive — 20-30%): PRP injection (platelet-rich plasma — supports tendon healing with growth factors, evidence level increasing), ESWT (50-60% success). Surgical step (6-12 months refractory — 5-10%): arthroscopic subacromial decompression (acromioplasty — shaving undersurface of acromion, widening subacromial space), now limited to conservative-refractory cases — primary acromioplasty rates have decreased with questioning of Neer's classic impingement model. Bursectomy may be added if subacromial bursitis accompanies. Long-term progression of tendinopathy to tear is 20-50% — regular follow-up recommended even with successful conservative treatment.
Rotator cuff tendinopathy is generally managed with conservative treatment (physical therapy, NSAIDs, subacromial injection). Surgery is rarely needed and typically involves subacromial decompression. Untreated tendinopathy carries risk of progression to partial and full-thickness tear.