Femur/Knee Case #9

17 yo otherwise healthy male soccer player c/o nagging pain to Left knee for several months, with occasional swelling. He denies acute injury, stating pain is usually worse when exercising. Has begun to walk with limp in order to reduce pain. Denies fever, rashes, dysuria and sexual activity.

History and PhysicalAFVSSGen: WDWN, A&Ox4Neuro: CNs 2-12 intact,

Nml 5/5 motor strength and sensation x 4. Nml reflexes.

MSK: Pain and crepitation on forcible compression to medial femoral epicondyle during knee extension and flexion. No effusion, warmth, or erythema to knee. Walks with LLE slightly externally rotated.

Images

Diagnosis: Osteochondritis Dessicans

Thin rim of calcium separated from underlying bone.

MRI showing subchondral defect in medial femoral condyle

Initial X-rays may have occult fx, often missed unless advanced changes are present

Tx is different in adults vs children:Adults: usually require surgery to prevent

premature degenerative arthritisChildren: long-leg splint/Ortho referral,

minimum-weight bearing immobilization for minimum of 6 weeks If loose body fragment is present in joint space,

arthroscopic surgery recommended for all patients.

NSAIDS for analgesia

ED Management

Separation of joint surface cartilage/subchondral bone from the underlying bone

MC in the lateral aspect of medial femoral condyle (also in elbow and ankle) Unilateral (74% of cases) Twice as common in Males Classically occurs below age of 18

Rare conditions of unclear etiology – most likely from wear and tear, overloading on joint surface

Loose bodies may cause joint locking, pts may walk with leg externally rotated to avoid impingement of lesion on the femoral condyle

Prognoses: Better if: immature growth plate or bony fragment not detached –

Usually heals with non-operative tx Worse if: growth plate closed or detached bony fragment (leaves

defect in weight bearing region) – Arthroscopic tx with possible ORIF

Pearls

Additional Images

Loose bony fragment, medial femoral epicondyle

Demonstrating defect of articular carilage and subchondral bone

Gaillard F, Weerakkidy Y, et al. Osteochondritis dissecans, Radiology Reference Article: http://radiopaedia.org/articles/osteochondritis_dissecans

Simon RR, Sherman SC: Emergency Orthopedics, 6th ed. Chapter 9: Cervical Spine Trauma. www.accessemergencymedicine.com

Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed. Chapter 255: Spine and Spinal Cord Trauma

http://www.wheelessonline.com/ortho/osteochondritis_dissecans_of_the_knee

References