Proximal femoral Osteotomy

Proximal femoral osteotomy is a joint-sparing procedure that relies on maintaining the biologic integrity of the femoral head. Once common for hip dysplasia and arthritis of the hip, proximal femoral osteotomies are performed less commonly now. But they are still used in  the treatment of hip fracture nonunions and malunions and in cases of congenital and acquired hip deformities. 

For proximal femoral osteotomy, the goal is to correct the deformity and, in by doing that to realign the hip and lower extremity.

Proximal femoral osteotomies may be high cervical, intertrochanteric, greater trochanteric or subtrochanteric depending upon the location of the osteotomy.

Different Types of Proximal Femoral Osteotomy

Proximal femoral osteotomies are  of following types

Transpositional Osteotomy

Longitudinal axis of distal fragment  remains parallel to  the longitudinal terminal axis of proximal fragment.

For example McMurray osteotomy, Pauwel’s osteotomy & Putti osteotomy.

Angulation Osteotomy

Longitudinal axis of distal fragment forms an angle with that of proximal fragment.  For example, extension osteotomy for fixed flexion deformity [in saggital plane] and adduction or abduction osteotomy [coronal plane].

Indications for Proximal Femoral Osteotomy

Femoral Neck Nonunion

In femoral neck nonunion, the osteotomies aim to convert  vertically oriented fracture line to the horizontal so that the shear stresses at the fracture site becomes compressive to encourage osteogenesis and fracture union.

Intertrochanteric malunion

Intertrochanteric fracture malunion results in varus. Varus angulation results in shortening of the ipsilateral femur, shortening of the abductor musculature or lever arm, and often trochanteric-pelvic abutment on abduction, and a Trendelenburg gait.

In these cases intertrochanteric osteotomy aims to realign the hip joint, restore normal abductor mechanics, and remove leg length discrepancy.

Malunion of Slipped Upper Femoral Epiphysis

If a displaced slipped epiphysis heals in situ, a fracture malunion can result. After remodeling, this malunion is characterized by coxa vara, femoral shortening, and retroversion of the femoral neck with a significant loss of hip motion.

In amenable cases osteotomies can realign the slipped epiphysis and contain spherecity of the femoral head.

In healed cases, osteotomies aim to correct the varus, equalizes limb length and abductor tension, thereby normalizing gait.

Fibrous dysplasia

Repeated microfractures of the femoral neck lead to progressive displacement and healing of the femur in varus and the classical shephered crook deformity.

Valgus-producing proximal femoral osteotomy serves to prevent progression of the deformity and the development of a fracture and reestablish a more normal femoral head–acetabular relationship.

Developmental dysplasia of hip

Adults with developmental hip dysplasia have acetabular as well as femoral deformity.

There is valgus of the femoral neck and anteversion. The acetabulum is shallow and ill-formed.

A varus-producing proximal femoral osteotomy with derotation of the anteverted neck improves femoral head orientation.

Contraindications

• The presence of active infection
• Limitations of hip motion
• Inflammatory arthritis

Different Osteotomies Carried in Different Conditions

• Non Union # Neck Of Femur [ Commonly done osteotomies are McMurry’s osteotomy, Dickson’s osteotomy, Putti’s osteotomy, Schanz osteotomy]
• Osteoarthritis [ Pauwel’s osteotomy, Mc Murrays osteotomy]
• Unstable Intertrochanteric # [ Dimon Hughston osteotomy, Sarmiento’s osteotomy]
• Unreduced Congenital Hip Dislocation [Lorenz bifurcation osteotomy, – Schanz low sub trochanteric osteotomy]
• Congenital Coxa-Vara [ Cuneiform osteotomy by Fish, Pauwel’s Y osteotomy, Basilar osteotomy
• Leg Calve Perthe’s Disease [ Varus de-rotation osteotomy]
• Avascular Necrosis of Femoral Head [Sugioka – Trans trochanteric osteotomy, Varus de-rotation osteotomy.]

Evaluation of the patient for Proximal Femoral Osteotomy

• Complete clinical evaluation

  • Extent of deformity
  • Planes of deformity
  • Range of motion of both the hips
  • Any hip or knee contracture
  • Limb-length discrepancy
  • Previous incisions, skin quality,
  • Any signs of previous infection

• Lab Studies

  • CBC
  • ESR
  • CRP
  • Routine preoperative blood work

• Imaging

  • Standing anteroposterior pelvis radiographs
    • Neck-shaft angle
    • Hip joint integrity.
  • Lateral View
    • Sagittal deformity.
  • Computed tomography/MRI
    • Confirm the presence of a nonunion.
    • For osteomyelitis.

Procedure of Proximal Femoral Osteotomy

• Patient is operated on radiolucent fracture table so as to have intraoperative fluoroscopic control
• The approach and site of osteotomy would depend on the indication for osteotomy and the osteotomy planned. Often, with internal fixation, lateral approach is used.
• The procedures for different osteotomies are discussed separately
• External fixation is typically reserved for low intertrochanteric or subtrochanteric osteotomies.

Complications

Major complications of a femoral osteotomy include the following:

• Infection
• Neurovascular injury
• Nonunion
• Inability to obtain or maintain a full correction
• Chronic postoperative pain
• Deep vein thrombosis
• Painful hardware
• Joint stiffness

Important osteotomies of proximal femur

 Mcmurray’s  Displacement Osteotomy

This osteotomy is mostly done in treating non-union of trans-cervical fracture neck femur  and occasionally in osteoarthritis of hip.

The the aim is to make  the fracture line more horizontal and thus convert shearing forces to compressive to promote union.

Thus, McMurray’s osteotomy allows painless weight bearing even in presence of persistent non-union which is a marked advantage over angulation osteotomy.

Since the distal fragment is placed directly under the head of femur, weight transmission occurs from the head to the distal shaft fragment bypassing the fracture site. Hence even it the fracture does not unite, painless weight bearing is possible.

In Mcmurray’s osteotomy, distortion of proximal femoral anatomy can compromise a replacement in the future and should be taken into consideration.

The osteotomy starts below the level of lesser trochanter laterally and proceeds in an oblique manner to exit proximal to the lesser trochanter medially.

The lower fragment is displaced medially by manual pressure and abduction so that it is placed under the head of the femur.

Cancellous screws or Smith-Peterson nail in conjunction with Tupman plate are commonly used fixation devices.

 Postoperatively, patient is mobilized as soon as symptoms permit and is put on physical therapy, starting with  touch-down weight bearing until union occurs. Once union occurs, unrestricted rehabilitation is possible.

 Schanz Angulation Osteotomy

This is a valgus osteotomy where the shaft is set into abducted position, so that the shearing stress of weight bearing and muscle retraction becomes an impaction force.

It is done in cases of non-union of fracture of neck of femur and congenital dislocation of hip.

The femur is cut transversely at ischial tuberosity level & the proximal fragment is adducted until it rests against the side wall of the  pelvis.

This lengthens the distance of the gluteus medius and provides a fulcrum so that adequate leverage of the muscle is obtained.

The position is maintained by plate fixation.

 Pauwel’s Varus Osteotomy

Varus femoral osteotomies are designed to elevate the greater trochanter and move it laterally to restore joint congruity and decrease the force acting on the edge of the acetabulum moves to the middle of weight-bearing surface.

The osteotomy is indicated in  antalgic abductor limb, abduction deformity, painful adduction and valgus neck shaft angle.

Varus osteotomy shortens the limb to some degrees and increases the prominence of greater trochanter. It also results in overloading of the medial compartment of knee.

Pauwels Valgus Osteotomy

Valgus intertrochanteric femoral osteotomies transfer the center of hip rotation medially from the superior aspect of the acetabulum to decrease the weight bearing area of femoral head .

It is not done in hips with flexion less than 60 degrees

–          Flexion of less than 60°

–          Knock knees as this will increase the deformity at knee.

Sugioka Transtrochantric Rotational Osteotomy

This is done for osteonecrosis to prevent progressive collapse of the articular surface and to improve the congruity of hip joint.

To do this the femoral head and neck segment is rotated anteriorly around its longitudinal axis, though a trans-trochantric osteotomy.

So that the weight bearing force is  transmitted to the posterior articular surface of femoral head, which is not involved in the ischemic process.

Postoperative skin traction is given for 2-3 weeks active range of motion exercises of hip are begun at 10-14 days.       

Cuneiform Osteotomy of Femoral Neck

 The osteotomy is recommended in cases of slip greater than 30 degrees.

After exposure, adjacent to the epiphyseal plate, a wedge shaped piece of bone is removed with its base directed anteriorly and superiorly with apex psotero-inferiorly.

Eepiphysis is reduced by flexion, abduction and internal rotation of limb, taking care to put much tension on the posterior periosteum, capsule and vessels.

 Dimon-Hughston Osteotomy

It is a medial displacement osteotomy used in altering the pathologic anatomy of  he unstable intertrochanteric fracture to convert that to a stable, albeit nonanatomic position .

The procedure involves

• Transverse osteotomy of the proximal femoral shaft at the level of the lesser trochanter
• Osteotomy and proximal displacement of the greater trochanter and the attached abductor muscles
• Medial displacement of the femoral shaft
• Impaction of the proximal fragment into the medullary canal of the femoral shaft. If the proximal fragment is firmly impacted into the femoral shaft, a stable construct will result.

Sarmiento osteotomy

It is a valgus osteotomy for unstable intertrochanteric fractures to provide a medial cortical butterss.

This technique involves

• Oblique osteotomy of the proximal femoral shaft, extending from the base of the greater trochanter to a medial position, 1cm distal of the apex of the fracture surface
• Implant placement into the proximal fragment, 90.degre to the fracture surface
• Reduction and impaction of the osteotomy

 Outcomes of Proximal Femoral Osteotomy

When proximal femoral osteotomy is used for the correction of congenital/acquired deformities and repair of hip fracture nonunion, results have been favorable. Hip range of motion, gait, pain, leg-length discrepancy, and patient satisfaction are improved.

With regard to the use of proximal femoral osteotomy in the nondeformed hip with osteoarthritis, long-term follow-up reveals that many patients go on to require total hip arthroplasty.