Osteotomies Around the Hip: Foundational Concepts
Hip osteotomy is a reconstructive procedure that changes the orientation, position or geometry of the proximal femur, acetabulum or entire hemipelvis. Its objectives are to improve femoral-head containment, restore a functional weight-bearing area, correct abnormal hip biomechanics, relieve pain, prevent or delay secondary osteoarthritis, and facilitate later arthroplasty when required. The choice depends on the patient’s age, symptoms, range of motion, congruence of the joint, cartilage status, deformity, skeletal maturity and the presence or absence of femoral-head avascular necrosis.
The fundamental biomechanical principle is to redirect load through a congruent and viable portion of the femoral head. A successful osteotomy should improve containment without causing impingement, excessive joint pressure, limb-length inequality or loss of motion. In developmental dysplasia, acetabular reorientation increases the weight-bearing coverage and reduces the lateralisation of the hip. In proximal femoral deformity, alteration of the neck-shaft angle, femoral version or flexion-extension relationship can improve containment and the abductor lever arm.
Classification of Dysplasia Relevant to Osteotomy
The Crowe classification describes superior migration of the femoral head in developmental dysplasia on an anteroposterior pelvic radiograph. The amount of migration is expressed as a percentage of the vertical height of the femoral head.…