Chondrolysis, also known as acute cartilage necrosis, represents acute cartilage destruction of the femoral head. It is one of the complications that are specifically associated with slipped capital femoral epiphysis (SCFE). It may also be associated with infection, specifically septic arthritis. It is a poorly understood phenomenon.
The quoted incidence is 5–7%. But it can be very variable, depending on the treatment options (e.g. percutaneous pinning , Spica cast ). Females are more likely to be affected than males.
Typically, symptoms develop between 2 and 4 months after treatment, but occasionally they are present on the initial presentation before treatment.
Stiffness and persistent pain in the groin or upper thigh are reported. Walking and other activities are adversely affected.
Reduction in the arc of motion of the hip in all planes and motion is usually painful during the hip examination.
Chondrolysis can occur spontaneously, before any treatment, or may be found when the patient first presents with SCFE. It can also occur after any type of treatment but it is particularly associated with pin joint penetration.
Narrowing of joint space is the hallmark of the disease although this is difficult to appreciate in children where there is incomplete ossification of the femoral head.
In a completely ossified hip, loss of more than 50% of the joint space compared with the unaffected contralateral side, or absolute measurement of 3 mm or less is considered highly suggestive of the condition.
Bony erosion and periarticular osteoporosis can also be seen.
Treatment and prognosis
The natural history can follow two major courses:
- some children will undergo a late reconstitution of the joint space to a certain degree
- others will undergo nearly complete ankylosis, often in a bad position