Adolescent Female with Hip Pain
Radiology Cases in Pediatric Emergency Medicine
Volume 4, Case 19
Collin S. Goto, MD
Children's Medical Center of Dallas
University of Texas Southwestern School of Medicine
This patient is a previously healthy 11 year old
female who presents to the emergency department with
a 2 week history of gradually worsening bilateral hip
pain, left greater than right. She denies involvement of
any other joints. There is no history of trauma, fever,
weight loss, recent illness, and the patient denies
sexual activity. The family history is negative for
Exam: VS T 36.7 (Tympanic), P 72, RR 18, BP
110/68. She is of average body build, with a weight of
38 kg. She is alert and not ill-appearing. Head, neck,
lung, heart, abdominal, and neurologic exams are all
within normal limits. On examination of the lower
extremities, she has pain with both active and passive
range of motion in both hips, left greater than right.
Pain is elicited with all movements, including flexion,
extension, adduction, abduction, and internal/external
rotation. Nearly full passive range of motion can be
attained, but with difficulty and pain. There is no
erythema, swelling, or increased warmth. There is no
muscle atrophy distally. She walks with a slow, stiff,
antalgic gait (see Case 16 in Volume 4, A Limping
6-Year Old). The remaining joints of the upper and
lower extremities are not involved.
Laboratory Results: CBC WBC 8,800, 44%
neutrophils, 41% lymphocytes, 5% monocytes, 8%
eosinophils, and 2% basophils. The hemoglobin,
hematocrit, and platelet count are normal. The
erythrocyte sedimentation rate is 9 mm/hr, and the
C-reactive protein is < 1mg/dL. Hip radiographs are
View hip radiographs.
Do you see anything abnormal about these
radiographs. Clinically, we would expect to find
potential abnormalities in both hips, with the left worse
than the right. Thus comparing one side to the other
may not be as helpful as in a unilateral problem.
AP and frogleg views of the hips demonstrate
bilateral joint space narrowing, left greater than right. In
addition, there are early subchondral cysts seen on the
left within the femoral head. There is no evidence of
fracture, dislocation, or slipped capital femoral
epiphysis. This condition is known as idiopathic
chondrolysis of the hips.
Teaching points and Discussion:
1. Idiopathic chondrolysis of the hip was first
described by Jones in 1971 as a condition
characterized by an extensive loss of articular cartilage
of the femoral head and acetabulum, in the absence of
known etiologies of chondrolysis, such as slipped
capital femoral epiphysis (SCFE), prolonged
immobilization, infection, rheumatoid arthritits, and
2. The typical presentation of idiopathic
chondrolysis of the hip is that of an afebrile, previously
healthy, adolescent female with an insidious onset of
hip, thigh, or knee pain, associated with a limp and
progressive loss of movement of the affected hip.
Patients often have restricted hip movements at the
time of presentation, with fixed flexion, abduction, or
adduction deformities. Hip radiographs show a
characteristically narrowed joint space. The disease
process may involve one or both hips. Infectious
workup, including white blood cell counts, blood
cultures, and ESR are normal. Rheumatologic workup
similarly is negative.
3. The differential diagnosis for hip pain in
adolescents includes septic arthritis, toxic synovitis,
trauma, SCFE, Legg-Calve-Perthes disease (juvenile
idiopathic avascular necrosis of the femoral head),
monoarticular rheumatoid arthritis, tuberculosis,
leukemia, synovioma, and other neoplasms. Narrowing
of the hip joint space is an important finding that
virtually excludes acute synovitis, bacterial and viral
arthritis, trauma, or the early stages of juvenile
rheumatoid arthritis (JRA) or spondyloarthritis. In the
early stages of these disorders, the hip joint space is
normal or widened. In addition, monoarticular JRA is
predominantly a disease of the knee, ankle, or wrist.
The hip joint is very rarely affected, especially in girls.
The radiographic diagnosis of fractures, neoplasms,
SCFE, and Legg-Calve-Perthes disease should be
4. Early radiographic findings of idiopathic
chondrolysis of the hip include symmetrical joint space
narrowing (due to loss of articular cartilage),
periarticular osteoporosis, erosions of the articular
cartilage of the acetabulum and femoral head, blurring
of the subchondral line, subchondral cyst formation, and
protrusio acetabuli (as noted by a progressive increase
in the center edge of Wiberg). Late changes include
marginal osteophyte formation, lateral buttress
formation, early closure of capital and trochanteric
epiphyseal plates, widening of the femoral head and
neck, and ankylosis.
5. The method of measurement of the width of the
femoral head and neck is described in Bleck (1983).
View diagram of this method.
The center of the head (O) is located by the method
of Wiberg. The femoral neck is bisected through the
center (line ab). Line cd runs perpendicular to line ab
through the center of the head. The length of line cd to
the margins of the head is the width. Line ef is drawn
perpendicular to line ab at the junction of the head and
neck to measure the width of the femoral neck.
6. The method of measurement of the width of the
hip joint space on an anteroposterior radiograph of the
hips is also described in Bleck (1983).
View diagram of this method.
The center of the femoral head is located and the
line for measurement of the width of the femoral head is
marked. The femoral head is bisected by a line
perpendicular to the line for measurement of the width.
Each half segment (90 degrees) is divided into four
quarters of 22.5 degrees. The width of the joint within
the first lateral quadrant of the bisected head is
By this method, our patient's hip joint width
measured 1 mm on the left and 2-3 mm on the right.
Normal hip joint width is reported to be 3-5 mm.
7. Histologic features of idiopathic chondrolysis of
the hip include thickening of the capsule with
edematous changes in the capsule and synovium.
There are articular surface changes with fibrillation,
fragmentation, and progressive loss of cartilage. An
infiltration of lymphocytes is seen within the synovium,
and there may be degeneration of chondrocyte nuclei
and loss of cells in the lacunae.
8. Early reports suggested that therapy should
consist of physical therapy, non-weightbearing, and
non-steroidal anti-inflammatory drugs. Soft tissue
releases and traction were occasionally used to treat
contractures. However, many cases resulted in a poor
outcome with fibrous ankylosis and loss of movement in
the hip. More recently, it has been suggested that
non-weightbearing does not adequately unload the hip,
and the positioning of the hip when crutches are used
may actually potentiate the flexion contracture. Casting
or any other immobilization is contraindicated as the
pathologic process involving the articular cartilage may
be compounded. Roy and Crawford reported a small
series of patients treated with subtotal circumferential
capsulectomy and muscle release, followed by an
aggressive rehabilitation program consisting of split
Russell's traction, continuous passive motion, and
limited weightbearing. This was supplemented by
active and passive range of motion exercises, resulting
in a resolution of symptoms, improvement in range of
motion and widening of the joint space, rather than the
usual progressive course.
9. Our patient's presentation was typical of
idiopathic chondrolysis of the hip. The history, physical
examination, laboratory data, and radiographs all
supported this diagnosis. The diagnosis is suggested
when an adolescent patient presents with insidious
onset of hip pain, radiographs show a narrowed hip joint
space, and known causes of chondrolysis, such as
SCFE, prolonged immobilization, or trauma are absent.
Infection is unlikely if the patient is afebrile, with a
normal white blood cell count, ESR, and CRP. In
addition, the hip joint space is usually increased with
infection, rather than decreased. Monoarticular JRA
rarely affects the hip, and in the early stages, typically
demonstrates a widened joint space with an effusion,
and an increased ESR and CRP. Thus, the
radiographic finding of a narrowed hip joint space in
patients presenting with hip pain is clearly an important
distinction which limits the differential diagnosis
significantly. Awareness of the clinical entity of
idiopathic chondrolysis of the hip is important because
of the loss of function and severe disability often
associated with it.
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