IDIOPATHIC CHONDROLYSIS

FRANK CUCE, D.O., Orthopaedic Surgery Resident

KIRK W. DABNEY, M.D., Attending Pediatric Orthopaedic Surgeon

February 13, 1996

CLINICAL CASE PRESENTATION

ORTHOPAEDIC DEPARTMENT

THE ALFRED I. DUPONT INSTITUTE

WILMINGTON, DELAWARE

CASE HISTORY

This is a 12 year old Asian female with insidious onset of left hip pain 4 months in duration. At one point, her pain was so severe she could not bear weight and had to be picked up from school. She denies trauma to the hip. She could not participate in sports secondary to pain and also developed a limp with apparent leg length discrepancy secondary to pelvic obliquity and local muscle spasm. She complains of no other joint symptomatology. Her previous medical history is negative.

PHYSICAL EXAM

She was afebrile on presentation to the Alfred I. dupont Institute. Physical examination demonstrated the following positive findings:

• Left hip 15 degrees abduction, 10 degrees addiction, 10 degrees external rotation, 0 degrees internal rotation.
• Pain on range of motion, left hip
• Left lower extremity was 1.5 cm longer than the right lower extremity
• Antalgic gait

XRAYS

A CT scan in August showed joint effusion which was aspirated and evaluated. The aspirate was negative for infection or other pathology.

An arthrogram performed was also negative. Both studies done at outside facilities.

Recent radiographic findings revealed the following: Bone scan with increased uptake left hip on both sides of joint. Joint space narrowing left hip to 2 mm.

LAB VALUES

• PPD, HLA-B27, CBC with differential, Lyme panel, ANA -All within normal limits.
• ESR mildly elevated at 31 mm/hr.

IDIOPATHIC CHRONDOLYSIS

Chondrolysis represents a process characterized by progressive destruction of articular cartilage resulting in secondary joint space narrowing and stiffness.

Types: May follow infection, trauma, prolonged immobilization and severe burns about the lower extremities. Also, it may be a complication of slipped capital femoral epiphysis.

Another type is idiopathic, characterized by an acute form of rapidly progressive chondrolysis occurring most frequently during adolescence with isolated involvement of the hip joint, but without a demonstrable cause.

HISTORY

Jones in 1971 described chondrolysis not associated with SCFE in black adolescent girls. Since that time, reports of idiopathic scoliosis have been recorded. As of 1989, after Daluga and Millar's study, 42 hips have been recorded. The female to male ratio is 6:1 and 52% of these patients are Caucasian.

ETIOLOGY

Etiology is unknown. Proposed theories include nutritional abnormalities, mechanical injury, ischemia, abnormal intracapsular pressure, and an inherent abnormal chondrocyte metabolism within the articular cartilage. The most accepted theory is that proposed by Golding in 1973, which postulated articular cartilage resorption to be secondary to an autoimmune response in genetically susceptible individuals.

INCIDENCE

This remains unreported in the literature, although 42 have been reported up to 1989. (Incidence of chondrolysis in SCFE is 8.2%).

CLINICAL PRESENTATION

• Adolescent girl average of 12.5 years.
• Right hip slightly higher than left hip
• Insidious onset of pain in anterior or medial side of affected hip associated with joint stiffness and limp.
• Patient is afebrile
• Restriction of motion in all planes with associated muscle spasm
• Contracture about the joint; most commonly, fixed flexion, abduction and external rotation

LABORATORY

CBC, UA, RF, ANA, HCA-B27, Blood culture, and TB (PPD) are WNL.

ESR can be slightly elevated and rarely over 30.

XRAYS

• Hallmark is narrowing of the joint space from normal 3-5 mm to values <3 mm.
• Associated osteopenia of the periarticular osseous structures
• Irregular blurring of subchondral sclerotic lines
• Enlargement of the fovea capitis femori
• With time, can develop mild coxa magna and femoral neck widening and frequently a premature closure of the proximal femoral physis and trochanteric apophysis.
• Mild protrusion and a lateral buttressing osteophyte at the acetabulum
• Limited area of periosteal new bone formation along inferior femoral neck

RADIOGRAPHIC TESTS INCLUDE

• Arthrography - help document cartilage resorption and joint space narrowing
• Bone scan shows increased uptake on both sides of joint
• CT Pelvis - document subchondral bone changes, cartilage resorption, and narrowing of joint space
• MRI - may be of benefit, but there is no large volume of experience using MRI found in the literature

PATHOLOGY

• Capsule is routinely thickened
• Lusterluss cartilage with irregular thinning, fibrillation and fragmentation
• Microscopic review of biopsy of synovium demonstrates nonspecific chronic inflammation

DIFFERENTIAL DIAGNOSIS

• Infectious arthritis including TB: Will see increased CBC, ESR, Temp, and positive PPD.
• Juvenile rheumatoid arthritis: There is an extended period of time with symptoms prior to chondrolysis. Rarely see restrictions in range of motion as that seen with Idiopathic Chondrolysis.
• Seronegative spondyloarthropathy: You will see additional joint involvement and the HLAB-27 will be positive.
• Pigmented villonodular synovitis: Has a more chronic and prolonged course. Usual findings include cystic erosions in subchondral bone and a bloody aspirate.

TREATMENT

• Early recommended treatment included corrective osteotomy, bony fusion, or joint arthroplasty.
• investigators proposed early and prolonged spica cast treatment until fibrous ankylosis was achieved.
• investigators employed treatment protocol including therapeutic doses
• of NSAIDS, aggressive PT, periodic traction and bedrest, prolonged non-weight, bearing or limited weightbearing, CPM.
• Current recommendations embrace philosophy of a more favorable long-term prognosis for improved motion and function.

REFERENCES

1. Bleck EE. Idiopathic chondrolysis of the hip. JBJS (AM) 1983;65:1266.
2. Daluga DJ, Millar EA. Idiopathic chondrolysis of the hip. JPO 1989;9:405.
3. Duncan JW, Nasca R, Schrantz J. Idiopathic chondrolysis of the hip. JBJS (Am) 1979;61:1024.
4. Duncan JW, Schrantz JL, Nasca RJ. The bizarre stiff hip-possible idiopathic chondrolysis. JAMA 1975;231:382.
5. Kozlowski K, Scougall J. Idiopathic chondrolysis-diagnostic difficulties. Pediatr Radiol 1984;14:314.
6. Lovell and Winter. Idiopathic chondrolysis of the hip. Pediatric Orthopedics 1037-1045.