Unusual insertion of LCL

OCD with fragment in suprapatella pouch

Labral tear with intraosseous ganglion

Anterior tibial neuropathy from ganglion cyst

Longitudinal biceps split

High grade undersurface and intra substance tear of SST

30M

AxGrT1

SagPD

Growth arrest / recovery fat lines

• 25 year-old male

• History: Left knee gives out and is swollen. Rule out loose body vs ACL tear.

• Chronic complete ACL tear

• Meniscocapsular separation, posterior horn medial meniscus

• Altered morphology posterior and mid lateral meniscus (tear vs post-surgical)

• OA medial, lateral tibiofemoral compartments

A: Meniscocapsular separationB: Tear of deep layer of MCLC: Peripheral meniscal tear

Meniscocapsular Separation

A: Corner tearB: Meniscal displacementC: Peripheral edema, irregularity

From: De Maeseneer et al. Eur J Rad 41 (2002) 242-252

DA Rubin, CA Britton, JD Towers, CD Harner. Are MR imaging signs of meniscocapsular separation valid?

(Radiology 1996: 201: 829-836)

• Fluid deep to MCL

• Increased perimeniscal signal intensity

• Abnormal lateral fascicles

• Meniscal displacement relative to tibia

• Peripheral meniscal corner tears

Conclusion: The PPV for MR diagnosis of meniscocapsular separation is low (9% medially,13% laterally)

Case 2

• Female (Portugal)

• History:

Pain. Patellar transfer surgery 2 months ago. R/o chondromalacia patellae

Case 2: Findings

• Mature ossification in adductor magnus

• Post-operative changes in patellar tendon and Hoffa’s fat pad

Pelligrini-Stieda Syndrome

• Ossification at medial aspect of the knee in either

• Medial collateral ligament

• Adductor magnus (less common)

• Cause is presumably post-traumatic

Case 3

• Eight year-old male (Portugal)

• History:Ostochondritis dissecans

De Smet A, Ilahi, O, Graf B. MR criteria for stability of osteochondritis dissecans in knee and ankle.

Skeletal Radiol (1996) 25: 159-163

• High-signal-intensity line at interface of fragment and parent bone

• Cyst formation

• Focal defect in cartilage and subchondral bone

• High-signal fluid passing into the lesion

O’Connor et al. Osteochondritis dissecans of the knee in children. A comparison of MRI and arthroscopic findings

J Bone Joint Surg [Br] 2002;84-B: 258-262

• High-signal interface may not indicate instability (granulation tissue vs fluid)

• Accuracy of MR for staging OCD lesion improved from 45% to 85% by interpreting high-signal interface as predictor of instability only when accompanied by breach in articular cartilage on T1

Case 4

• 56-year-old male (Virginia)

• History (M.D.): Greater tuberosity fracture. R/o rotator cuff tear.

• History (patient): Swimming and body surfing in Hawaii 2 weeks ago; struck shoulder. Fracture/dislocation.

Case 5: Findings

• Fracture of posterolateral humeral head with avulsion of teres minor insertion

• Joint effusion with large posterior collection

• Extensive muscle edema and hemorrhage

• Avulsion of infraspinatus tendon at insertion

• Probable rupture of intraarticular biceps

• Avulsion of posterior capsule

• Supraspinatus tendinopathy

Ovesen J, Sojbjerg JO. Posterior shoulder dislocation.

Acta Orthop Scand. 1986; 57: 535-536.

10 cadaver shoulders, provoked posterior subspinous gh joint dislocation

Ovesen J, Sojbjerg JO. Posterior shoulder dislocation. Acta Orthop Scand. 1986; 57: 535-536.

• In 10/10: Teres minor rupture, posterior capsule rupture, and infraspinatus tear

• In 8/10: Lower subscapularis tear

• In 10/10: Intact supraspinatus and CH ligament

Case 5

• 25-year-old male (Navy Medical Center)

• History: Scaphoid fracture. R/o AVN

Diagnosing AVN in Scaphoid Non-Unions

• Conventional radiography and CT: sclerosis of proximal fragment doesn’t correlate

• Bone scintigraphy: Very sensitive, non-specific

• Surgery: Inspection of punctate bleeding points most accurate

• MRI: Low T1, low T2 not reliable

Cerezal et al. Usefulness of gadolinium-enhanced MR imaging in the evaluation of scaphoid non-unions.

AJR 2000; 174: 141-149

• 30 patients, MRI, surgery, 1-yr follow up

• % enhancement of proximal pole was evaluated (>80%, 50-80%, 20-50%, <20%)

From: Cerezal et al. Usefulness of gadolinium-enhanced MR imaging in the evaluation of scaphoid non-unions. AJR 2000; 174: 141-149

From: Cerezal et al. Usefulness of gadolinium-enhanced MR imaging in the evaluation of scaphoid non-unions. AJR 2000; 174: 141-149