Femoral Head Deformity

In Perthes disease, the resultant femoral head deformity may lead to abnormal mechanical function of the hip. The morphology of the proximal femur after healed Perthes disease is the single most important factor predicting the long-term outcome. [9, 14, 20] Typically, the deformities include a high-riding greater trochanter, a short femoral neck, and an aspherical femoral head-neck junction. Complex deformities of the proximal femur can cause both intra-articular and extra-articular femoro-acetabular impingement, which can lead to degenerative hip pain, restricted range of motion, and impaired abductor function. [1, 3, 13, 18]
The resulting deformities include: coxa vara (decreased angle of the femoral shaft to center of the femoral head resulting in a shortened leg), coxa plana or magna (enlarged, flattened, mushroom shaped head), and a relative overgrowth of the greater trochanter. The prominent trochanter paired with a shortened femoral neck and mushroom shaped femoral head can lead to femoro-acetabular impingement with a consequent chondrolabral …show more content…
[6], after studies on the blood supply to the femoral head. [8] This approach allows complete access to the femoral head and acetabulum with minimal risk of avascular necrosis of the femoral head. [6] In the management of post-Perthes sequelae, the approach allows complete dynamic evaluation of hip motion to determine the areas of impingement (anterior, lateral, antero-lateral or global), and hence it facilitates the correction of the cam deformity by means of a head-neck osteochondroplasty. Relative femoral neck lengthening or trochanteric advancement to correct extra-articular impingement due to a high-riding greater trochanter and a short wide neck can be performed. Finally, correction of all femoral deformities through a single surgical approach with a low risk of avascular necrosis to the femoral head is possible. [3, 18,