Review Question - QID 210153

This patient is >8 years old and has Legg-Calve-Perthes (LCP) of his right hip, lateral pillar Group B. In this age group, the treatment of choice is a containment surgery involving an osteotomy of the femur and/or acetabulum.

Legg-Calve-Perthes (idiopathic avascular necrosis of the proximal femoral epiphysis) carries a different prognosis based on patient age and involvement of the lateral pillar. In children <8 years old and in children with lateral pillar Class A involvement, initial treatment is non-operative and consists of observation, activity restriction, and physical therapy. In children >8 years of age with group B or BC disease, treatment consists of containment procedures including proximal femoral varus osteotomies and/or pelvic osteotomies.

Rosenfeld et al. performed a retrospective case series of 172 patients (188 affected hips) diagnosed with LCP before age 6. They found a favorable prognosis for LCP with an onset before age 6. Children with lateral pillar Group B/C and C lesions diagnosed between the ages of 4 and 6 had poorer outcomes.

Herring et al. described the Lateral Pillar Classification of LCP (later known as the Herring classification). They divided patients into three groups based on the radiolucency of the lateral pillar of the femoral head, which appeared to correlate with prognosis. Group A had no involvement of the lateral pillar, Group B had <50% height loss, and Group C had >50% height loss. (Group BC was added later).

Figure A is an anteroposterior pelvic radiograph demonstrating avascular necrosis of the right hip with <50% height loss of the lateral pillar of the femoral epiphysis. Illustration A is a diagram illustrating the Lateral Pillar Classification. Illustration B is a cartoon of a patient before and after a Dega and a varus derotational osteotomy, demonstrating containment of the femoral head post-operatively.

Incorrect Answers:
Answer 1: Observation, activity modification, and symptomatic treatment are appropriate in children <8 years old; the radiograph demonstrates a lateral pillar Group B lesion.
Answer 2: Observation, activity modification, and symptomatic treatment are appropriate in children <8 years old.
Answer 4: The radiograph demonstrates a lateral pillar Group B lesion.
Answer 5: A containment surgery in the form of a femoral and/or acetabular osteotomy is the treatment indicated for LCP in this age group; the radiograph demonstrates a lateral pillar Group B lesion.