Case report

Idiopathic chondrolysis of the hip

Aziza Mounach

*

, Abderrazak Nouijai, Imad Ghozlani, Miriam Ghazi,

Ahmed Bezza, Lahcen Achemlal, Abdellah El Maghraoui

Rheumatology and Physical Rehabilitation Department, Mohamed V Military

Teaching Hospital, Rabat, Morocco

Received 27 July 2006; accepted 15 February 2007

Available online 14 August 2007

Abstract

Idiopathic chondrolysis of the hip is a rare disease in which gradual necrosis of the hyaline cartilage covering the femoral head and acetab-

ulum leads to joint space narrowing and motion restriction. Pain, motion range limitation, and radiographic joint space narrowing are the main
manifestations. We report 2 cases in 15-year-old girls, one black and the other Caucasian. Unexplained pain and motion restriction in the left hip
were the presenting manifestations. Narrowing of the hip joint space was noted on standard radiographs. Magnetic resonance imaging showed
a joint effusion in 1 patient and unevenness of the femoral head contour in the other. Laboratory tests including microbiological studies were
normal or negative. Nonspecific synovitis was found in biopsy specimens. Immobilization and traction were the main components of the treat-
ment strategy.
Ó 2007 Elsevier Masson SAS. All rights reserved.

Keywords: Chondrolysis; Idiopathic; Hip; Child; Stiffness

1. Introduction

Idiopathic chondrolysis of the hip manifests as gradual

motion restriction and marked joint space narrowing. This
uncommon condition affects prepubertal children. Females
are at far greater risk than males. No accurate epidemiological
data are available to estimate its incidence. Most publications
are anecdotal case reports or small case series. The diagnosis
relies primarily on elimination of causes of chondrolysis such
as infection, inflammatory hip disease, acetabular protrusion,
trauma, and avascular necrosis of the femoral head. The etio-
pathogenesis of idiopathic chondrolysis of the hip is unclear.
No curative treatment is available, and the prognosis is
guarded. We report 2 cases.

2. Case reports

2.1. Case 1

A 15-year-old black girl was admitted for a 2-month history

of pain and functional impairment in the left hip. She had no
history of tuberculosis, trauma, prolonged immobilization, or
transient hip pain (transient synovitis). She reported gradually
worsening mechanical pain in the left groin and increasing
motion restriction. Her general health was good and her
body temperature normal. She walked with a limp. The left
hip was painful to mobilization. Flexion was reduced to 60



and extension to 30



, while internal rotation, external rotation,

and abduction were nearly impossible. The spine and sacroil-
iac joints were normal to physical examination, and neither
were there any physical signs of enthesitis. The remainder of
the physical examination was unremarkable. The erythrocyte
sedimentation rate (ESR) was 10 mm/h, the C-reactive protein
(CRP) level was 0.4 mg/L, and the blood cell counts were nor-
mal. Tests were negative for rheumatoid factor, antinuclear

* Corresponding author.

E-mail address:

[e-mail]

(A. Mounach).

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antibodies, and HLA B27. On standard radiographs, circumfer-
ential joint space narrowing was seen in the left hip (

Fig. 1

),

with no evidence of acetabular protrusion or epiphysiolysis.
Findings were normal from radiographs of the sacroiliac joints
and thoracolumbar spine. Magnetic resonance imaging (MRI)
of the hip disclosed a joint effusion (

Fig. 2

) with no signs of vil-

lonodular synovitis or avascular necrosis. Gastric aspirate
smears and cultures were negative for the tubercle bacillus,
and the intradermal tuberculin reaction was also negative.
The chest radiograph was normal. Examination of a surgical
biopsy specimen from the hip disclosed nonspecific synovitis
with no evidence of tuberculosis. None of the findings from
the history, physical examination, laboratory tests, or radio-
graphs pointed to any of the causes of secondary chondrolysis.
The diagnosis was primary idiopathic chondrolysis of the hip.
The treatment consisted of analgesics and traction. Chondroly-
sis of the contralateral hip was diagnosed 1 year later.

2.2. Case 2

This 15-year-old Caucasian girl was admitted for pain and

motion restriction in the left hip of 4 months’ duration. Her med-
ical history was unremarkable, with no symptoms suggesting
transient synovitis. She reported pain in the left groin and grad-
ually worsening functional impairment with a limp and diffi-
culty putting on her shoes. Several courses of nonsteroidal
antiinflammatory drugs and physical therapy had failed to im-
prove the symptoms. Her body temperature was normal. The
left lower limb was 1 cm shorter than the right lower limb.
Pain and motion range limitation were noted at the left hip.
The spine and entheses were normal. Laboratory tests were un-
remarkable: ESR, 10 mm/h; normal CRP level; hemoglobin
13 g/dl; and normal findings from serum protein electrophore-
sis. Results were negative from tests for the tubercle bacillus
in sputum and gastric aspirate and from the intradermal tubercu-
lin test. The chest radiograph was normal with no evidence of
tuberculosis. Diffuse narrowing of the joint space was noted in
the left hip on plain radiographs (

Fig. 3

). MRI showed uneven-

ness of the femoral head contours (

Fig. 4

) and a small intraartic-

ular effusion. The clinical, laboratory, and radiographic findings
ruled out secondary chondrolysis. The diagnosis was idiopathic
chondrolysis of the hip. Analgesics and physiotherapy were pre-
scribed. Insoles were made to correct the leg length discrepancy.
Her condition was stable 18 months later.

3. Discussion

Idiopathic chondrolysis of the hip was first described by

Waldenstrom in 1930

[1]

. In 1970, Low reported 2 cases of

chondrolysis in patients with previously normal hips. Cases
of chondrolysis in the absence of other abnormalities were de-
scribed by Jones in 1971, Moule and Golding in 1974, and
Wenger Mickelson and Ponseti in 1975

[2]

. Additional cases

were reported subsequently

[3e6]

.

Fig. 1. Standard radiograph of the pelvis: circumferential narrowing of the
joint space in the left hip.

Fig. 2. Magnetic resonance imaging of the pelvis: high signal from the left hip
on T2-weighted sequences indicating a joint effusion.

Fig. 3. Standard radiograph of the pelvis: narrowing of the joint space and un-
evenness of the contour of the left femoral head.

657

A. Mounach et al. / Joint Bone Spine 74 (2007) 656e658

Although the pathogenesis of idiopathic chondrolysis of the

hip remains unknown, several theories have been put forward.
A role for inflammatory disease or infection receives no sup-
port from laboratory tests or histological studies. Mechanical
alterations related to prolonged immobilization have been
suggested

[7,8]

. Another hypothesis involves the release of

chondrolytic enzymes

[9]

. Blacks were overrepresented in

several case series, suggesting a role for ethnic factors. How-
ever, reports of cases in various ethnic groups militate against
this possibility

[9,10]

. Some patients had a history of transient

synovitis at 8 or 9 years of age or a history of diagnosed or
overlooked epiphysiolysis. The relationships between these 2
conditions and idiopathic chondrolysis remain unknown.

Idiopathic chondrolysis occurs between 9 and 15 years of

age. This characteristic age of onset is among the diagnostic
criteria. Nevertheless, cases diagnosed between 20 and 37
years of age have been reported

[10,11]

. Females contribute

80% of cases. Based on a literature review, Hughes

[12]

esti-

mated that the right hip was involved in 60% of cases, the left
hip in 35%, and both hips in 5%. Both our patients had in-
volvement of the left hip, although one of them subsequently
experienced involvement of the other hip.

Mechanical hip pain with gradual motion range restriction

causing a limp in late childhood or early adolescence is typi-
cal. The patient is otherwise healthy, and no triggering factors
are identified. Fixed flexion, abduction, and external rotation
of the hip may occur, probably as a result of the pain, as
near-normal mobility in all planes is noted during the exami-
nation of the hip under general anesthesia

[9]

.

Plain radiographs of the pelvis and hips support the diagno-

sis by showing circumferential joint space narrowing and peri-
articular demineralization of the femoral head and acetabulum.
The joint space may be severely narrowed (<1 mm). Other ra-
diographic changes may include absence of the subchondral

bone line, premature growth plate closure, acetabular protru-
sion, and overgrowth of the femoral head and neck.

MRI supplies valuable information. The MRI findings rule

out causes of secondary chondrolysis such as avascular femo-
ral head necrosis, reflex sympathetic dystrophy syndrome, and
villonodular synovitis. An intraarticular effusion may be visi-
ble

[13]

. Pathological findings include major capsular thicken-

ing and edema of the capsule and synovial membrane, with no
evidence of inflammation or caseous lesions. Fibrillation and
fragmentation of the cartilage are seen, with defects exposing
the subchondral bone. Fibrosis replaces the synovial tissue.

The diagnosis of idiopathic chondrolysis is one of elimina-

tion. Therefore, a thorough physical examination, laboratory
tests, and radiographs should be obtained to rule out causes of
secondary chondrolysis such as acetabular protrusion, epiphy-
siolysis, Perthes’ disease, rheumatoid hip disease, reflex sympa-
thetic dystrophy, and villonodular synovitis. A hip biopsy helps
to eliminate a joint infection, most notably tuberculosis.

The treatment usually rests on analgesics, nonsteroidal anti-

inflammatory drugs, and protection from weight bearing via
traction or crutches. Surgery is reserved for patients whose
symptoms fail to respond to medical therapy. Hip fusion

[12,14]

or arthrotomy to release the joint may be performed.

Arthrodiastasis is used in various conditions characterized by
restricted hip motion, including idiopathic chondrolysis.

The functional prognosis is guarded, with marked stiffness but

no pain in about half the affected joints. Recovery may occur in
about 54% of cases. Acetabular protrusion is extremely common.

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Fig. 4. Magnetic resonance imaging of the pelvis: narrowing of the joint space
and unevenness of the contour of the left femoral head.

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A. Mounach et al. / Joint Bone Spine 74 (2007) 656e658