Pediatric Hip Deformities: An Introduction

Abstract

The hip joint is one of the wonders of the human body. It is the largest joint, and its main function is to support the body’s weight during various daily activities of standing, walking, running, as well as various sports activities. Its ball-and-socket design allows a wide range of motion in several planes: flexion/extension, adduction/abduction, and internal and external rotation, thus allowing movements in almost any direction. The stability of that joint is increased by the presence of a labrum that deepens the acetabulum, a thick capsule, and the presence of very strong surrounding ligaments and muscles. However, the hip joint does have a major weakness, and that is its tenuous blood supply, which mostly comes from the medial circumflex artery supplying the epiphysis and metaphysis of the proximal femur. There is minimal blood supply coming from the nutrient arteries of the femur. Therefore, an insult or injury to that blood supply in the immature skeleton may have serious consequences on the viability and shape of the epiphysis and metaphysis and can result in abnormal anatomy. This may eventually lead to pain, decreased range of motion, abductor weakness, limp, limb length discrepancy, degenerative arthritis, and functional limitations. To help restore the normal anatomy to the hip joint and provide the patient with a painless mobile hip joint that allows him or her to ambulate and function in a satisfactory way remains the ultimate goal of any reconstructive surgery in the pediatric and adolescent population. This is challenging since it requires one to address not only the bony deformities but also to take into consideration the articular cartilage and the surrounding soft tissue envelope, specifically the hip musculature.