1983-1984• Carlos Pineda

• Roger Kerr

Roger Kerr, Los Angeles, CA

• 49 year old male with 6 month history of wrist pain and swelling.

• Past medical history is negative.

• PE: exquisite tenderness over distal ulna with loss of extension of 4th and 5th fingers.

• Routine laboratory studies are negative.

PA view of wrist: Enlargement of ulnar styloid with lytic/erosive change and soft tissue swelling.

49 year old male with 6 month history of wrist pain and swelling.

Coronal T1-weighted image: intermediate signal intensity mass surrounds and engulfs ECU tendon with erosion of distal ulna.

49 year old male with 6 month history of wrist pain and swelling.

Sagittal T1-weighted image: intermediate signal intensity mass surrounds and infiltrates ECU tendon.

49 year old male with 6 month history of wrist pain and swelling.

Consecutive axial T1-weighted images at level of ulnar styloid: ECU tendon is replaced by predominantly intermediate signal intensity mass that erodes distal ulna.

49 year old male with 6 month history of wrist pain and swelling.

Axial T1-weighted and axial T2-weighted images, respectively, at level of tip of ulnar styloid: mass of predominantly intermediate signal intensity has replaced ECU tendon and erodes ulna.

49 year old male with 6 month history of wrist pain and swelling.

• Bone scan revealed increased uptake of radionuclide at both 1st MTP joints, ankles and knees and at left midfoot and left shoulder.

49 year old male with 6 month history of wrist pain and swelling.

Differential diagnosis

• Tophaceous gout

• Tendon sheath lesions: giant cell tumor, fibroma , xanthoma

• Tuberculous tenosynovitis

• Rheumatoid arthritis with fibrous pannus

• Amyloidosis

• Clear cell sarcoma

Dx: Tophaceous gout of tendon

• At surgery ECU and EDC (4th,5th) tendons were debrided of chalky material and crystalline deposits.

• Histology: crystals with strong negative birefringence, dense fibrous connective tissue and mild chronic synovitis.

• Gout of tendon: usually in patient with established diagnosis of gout. Tendon infiltration, tenosynovitis, tendon rupture, entrapment neuropathy. Often mis-diagnosed clinically as tumor or tumor-like lesion.

• Gout: usually heterogeneous intermediate to low signal intensity on T2-weighted images related to fibrous tissue and urate crystals. Intense gadolinium enhancement.

Dx: Tophaceous gout of tendon

Roger Kerr, Los Angeles, CA

• 5 year old male presents with a 2 day history of pain and swelling of left knee.

• Vague history of knee pain 4 weeks ago treated with NSAIDS.

• No history of trauma or recent infection.

• No other joint problems.

• WBC=9.4; ESR=44; Febrile (up to 102)

Lateral radiograph of the knee

5 year old male presents with a 2 day history of pain and swelling of left knee.

AP radiograph of the knee

5 year old male presents with a 2 day history of pain and swelling of left knee.

Immediate (A) and delayed (B) 99mTcMDP images were interpreted as consistent with septic arthritis with no

evidence of osteomyelitis.

A B5 year old male presents with a 2 day history of pain and swelling of left knee.

• Joint aspiration yielded cloudy fluid with 80,000 WBC/mm3 (99% PMNs) and 100,000 RBC/mm3.

• Arthroscopic drainage and debridement of the joint was performed on the third hospital day.

• Patient was treated with IV antibiotic (Ceftazidine, then Vancomycin) but knee swelling and pain and fever persisted. On day 10, an MRI was obtained.

5 year old male presents with a 2 day history of pain and swelling of left knee.

A sagittal T2-weighted image reveals a large joint effusion, synovial hypertrophy, intra-articular debris and a large high signal intensity lesion of the patella c/w septic arthritis and osteomyelitis/bone abscess.

5 year old male presents with a 2 day history of pain and swelling of left knee.

5 year old male presents with a 2 day history of pain and swelling of left knee.

A

BB

CSuccessive axial intermediate-weighted images reveal extension of this lesion through the anterior cortex of the patella.

Diagnosis: septic arthritis of the knee and osteomyelitis/bone abscess of the patella

• Incision and drainage of the patella was performed and purulent fluid was removed.

• Histology revealed acute and chronic inflammation and Staph aureus was cultured.

• The patient recovered following a course of IV, followed by oral, antibiotics.

Osteomyelitis of the patella

• Rare – usually due to direct implantation from a break in the skin, puncture wound, septic bursitis or septic arthritis.

• Hematogenous spread to patella is exceedingly rare; rich blood supply and no physeal plate with its sluggish hemodynamics.

• Acute or insidious onset.

• Local signs or symptoms vs. systemic illness.

• Diagnosis is often delayed or overlooked as clinician assumes patient only has joint, bursal or soft tissue infection.

Osteomyelitis of the patella

• Clue to diagnosis: pt. not responding to standard management of septic arthritis.

• Surgical debridement indicted for subperiosteal/bone abscess or chronic osteomyelitis.

• In this patient, radiographs and bone scan were negative for osteomyelitis due to immaturity of patellar development. MRI was definitive.

• Roy DR et al: Osteomyelitis of the patella in children. J Ped Orthop 1991;11:364-366.