Femoral Osteotomy - Clinical Tree

Key Points

Intertrochanteric femoral osteotomy has lost popularity today.
Interest in addressing torsional deformities of the femur has recently come back to the fore.
Proximal femoral osteotomies are often used in the context of femoroacetabular impingement (FAI) surgery and/or treatment of hip dysplasia.
Osteotomies have shifted more proximally: femoral neck and intracapital osteotomies.
Femoral osteotomy must be performed with consideration for the long term (i.e., with minimal alteration of the proximal femoral morphology).

Introduction

Diseases of the hip cause pain, functional and ambulatory disability, and eventually gross deformity. As such diseases progress, they drive the individual through an escalation that starts with no symptoms and progresses to activity-related pain, then to a constant affliction with increasing pain and loss of function. Degenerative arthritis of the hip is now known to occur as a consequence of sometimes subtle, sometimes distinct morphologic abnormalities of the joint that produce articular loads in excess of physiologic limits. If the morphologic abnormality can be corrected or altered surgically to decrease excessive articular cartilage loading and improve hip stability, then this would potentially obviate or postpone the need for joint replacement surgery. Improved imaging and the evolution of surgical techniques have permitted a rapid growth in such hip preservation surgery over the last few decades. The orthopedic surgeon who performs hip preservation surgery must have mastered the precise vascular anatomy of the hip and have the requisite skills to address the intricate pathoanatomic deformities of not only the acetabulum but also the femur.

The principles of performing a femoral osteotomy therefore are to correct the anatomic abnormality, optimize hip congruity, and decrease cartilage load per unit area. This will improve joint biomechanics, range of motion, and ultimately improve the patient's symptoms and function. Femoral osteotomy is often a temporizing operation and its results are correlated with the fact that the biologic capacity of the cartilage to regenerate is not fully predictable or understood. The results of osteotomy should not be judged by the same parameters used to judge replacement surgery.

For a long time, femoral osteotomies were the workhorse for the treatment of developmental dysplasia of the hip (DDH). However, pelvic osteotomies, such as the periacetabular osteotomy (PAO), became increasingly popular because they have a high power of correction directly at the site of the deformity. As a consequence, the indications for intertrochanteric osteotomies are declining and these procedures rarely are performed for the treatment of DDH alone. With increased understanding of joint mechanics gathered during the process of understanding the concept of femoroacetabular impingement (FAI), the use of proximal femoral osteotomies has increased again. However, techniques extending more proximally to the femoral neck and head and involving intraarticular surgery are being used more frequently.

Historical Background

As an operation, proximal femoral osteotomy is almost 200 years old. Barton in 1827 reported on an intertrochanteric osteotomy performed on a sailor with an ankylosed hip and gross flexion and adduction deformity of the proximal femur. Amazingly, Barton performed this osteotomy on November 22, 1826, without anaesthesia using a saw! Because DDH has been a major problem, it is not surprising that the evolution of proximal femoral osteotomy followed that of treating this condition. In 1894, Kirmisson described an oblique subtrochanteric femoral osteotomy that corrected an adduction and flexion deformity. The distal fragment was extended and abducted; when the femur was realigned, the procedure corrected not only the deformity but also corrected some of the functional limb shortening. Similar procedures for DDH were performed by Baeyer, Lorenz and Schanz. The first report of a proximal femoral osteotomy to treat osteoarthritis (OA) was that of McMurray in 1935. He attempted to change the direction of load by a large medial displacement of the distal fragment, thereby unloading the articular cartilage. He also introduced the concept of the vascular effect of the osteotomy, whereby increased vascularity brought about by osteotomy healing would have a beneficial effect on the articular cartilage.

It was Pauwels, a student of Schanz, who clearly revolutionized the concept of femoral osteotomy in 1950 by introducing the concept of valgus and varus osteotomies to increase the weight-bearing surface area of the hip joint. For residual DDH, Pauwels advocated a varus osteotomy with excision of a medial wedge of bone. The shaft was then medialized to decompress muscular tension and to prevent secondary genu varum and subsequent medial knee joint OA from overload. For hip subluxation, coxa vara, and a medial capital drop osteophyte, Pauwels designed a valgus osteotomy with resection of a lateral wedge of bone. The shaft was then lateralized with the purpose of preventing genu valgum and secondary lateral compartment knee OA. Bombelli, in the 1970s, further expanded the Pauwels doctrine by introducing the concept of correction in the sagittal plane by adding flexion or extension to the varus or valgus angulation in an effort to further increase the weight-bearing surface area of the hip joint. Intertrochanteric femoral osteotomies are based on the principles of Pauwels and Bombelli.

With the development of the concept of FAI, enabled by the knowledge of the vascularity and technique of surgical dislocation of the hip, new technique—such as femoral neck osteotomies and intracapital osteotomies —have become possible. This has opened a new field for treatment of complex deformities of the proximal femur.

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