Will Secondary Impingement Show Up on MRI in a High School Basketball Player?
Yes, MRI will effectively visualize secondary impingement and its associated pathology in a high school basketball player, with a sensitivity of 90% and specificity of 80% for detecting the soft tissue abnormalities that characterize this condition. 1, 2
Understanding Secondary Impingement in Young Basketball Athletes
Secondary impingement is the predominant pattern in adolescent athletes, fundamentally different from the structural impingement seen in older adults. 3 In high school basketball players, this condition occurs when the humeral head fails to maintain proper centering in the glenoid fossa during overhead movements due to rotator cuff weakness combined with ligamentous laxity, rather than structural anatomic abnormalities. 3
What MRI Will Demonstrate
MRI can detect the key pathologic features of secondary impingement including: 4, 5
- Rotator cuff abnormalities - particularly undersurface (articular-side) partial-thickness tears of the supraspinatus tendon, which are more common than full-thickness tears in adolescent athletes 3
- Tendinosis and tendinopathy - characterized by tendinous enlargement and heterogeneous signal pattern with diffuse increased signal intensity on T1 weighting, often with slight increase on T2 weighting 4
- Subacromial bursal changes - inflammation and fluid accumulation visible on fluid-sensitive sequences 4
- Biceps tendon abnormalities - tenosynovitis or inflammation of the long head of biceps 4
- Scapular dyskinesis indicators - though this is primarily a dynamic clinical finding, MRI may show secondary muscle changes 3
MRI Technical Considerations
Noncontrast MRI is the appropriate initial advanced imaging study for this clinical scenario. 4 In the acute or subacute setting with secondary impingement, noncontrast MRI is preferred over MR arthrography because the condition typically produces joint effusion that provides natural contrast for assessing intra-articular soft-tissue structures. 4
MRI demonstrates high diagnostic accuracy with sensitivity of 90% and specificity of 80% for soft tissue abnormalities in impingement syndrome. 1, 2 The multiplanar capabilities make it ideal for detecting anatomical variations and the superb soft tissue contrast allows accurate differentiation between tendinopathy, partial-thickness tears, and full-thickness tears. 5
Critical Distinction: What MRI Shows vs. Clinical Diagnosis
A crucial caveat: While MRI will show the consequences of secondary impingement (rotator cuff pathology, bursal inflammation, tendon changes), it cannot directly visualize the underlying functional problem—the dynamic instability and poor neuromuscular control that causes secondary impingement. 6, 7
The diagnosis of secondary impingement remains primarily clinical, based on: 2
- Pain with overhead activities (88% sensitive)
- Positive Neer's test (88% sensitive, 33% specific)
- Positive Hawkins' test (92% sensitive, 25% specific)
- Scapular dyskinesis on examination
- Rotator cuff weakness patterns
Alternative Imaging Consideration
Ultrasound is equivalent to MRI for evaluating rotator cuff abnormalities (sensitivity 85%, specificity 90%) and may be preferred if local expertise is available, as it allows dynamic assessment and is less expensive. 4, 1, 2 However, ultrasound is inferior for evaluating intra-articular pathology and other soft tissue structures. 4
Clinical Implications for This Population
In adolescent basketball players specifically, MRI findings must be interpreted in the context that secondary impingement is driven by rotator cuff weakness, scapular dyskinesis, and ligamentous laxity rather than structural abnormalities. 3 The imaging serves to exclude other pathology and guide treatment planning, but the therapeutic focus should be on addressing the underlying biomechanical dysfunction through rehabilitation targeting rotator cuff strengthening and scapular stabilization. 1, 3
Common pitfall to avoid: Do not mistake the presence of MRI abnormalities for primary (structural) impingement in this age group—treatment must address the functional instability and muscle imbalances characteristic of secondary impingement in young overhead athletes. 3, 7