14: Single-Incision Supraperiosteal Triple Innominate Osteotomy

Single-Incision Supraperiosteal Triple Innominate Osteotomy

Indications

Correction of acetabular dysplasia in skeletally immature individuals in whom osteotomy through the triradiate cartilage may produce a growth arrest that may adversely affect continued acetabular growth and development.

Pitfalls

• Other osteotomies, including single innominate (Salter, Pemberton, or Dega), triple innominate (Steele, Tonnis), and Bernese periacetabular osteotomy, may be considered depending upon the familiarity of the surgeon, the age of the patient, and the degree and type of dysplasia.

• Simultaneous femoral osteotomy may be necessary in selected cases.

• Nonoperative treatment may allow further damage to the acetabulum and femoral epiphysis.

Controversies

• Precise timing and necessity of corrective acetabular surgery in asymptomatic dysplasia in skeletally immature patients remains controversial.

• Children with symptomatic acetabular dysplasia, particularly those exhibiting either clinical or radiographic signs of hip joint dysfunction, are candidates for surgical reconstruction. Clinical signs include limb, signs of hip instability, and pain with provocative testing. Radiographic signs include any evidence of arthrosis (sourcil sclerosis, cyst formation, epiphyseal osteochondritis) and worsening dysplasia (progressive disruption of Shenton’s line).

Examination/Imaging

A complete physical examination is necessary in the evaluation of children with developmental dysplasia of the hip. The patient’s stature, spinal alignment, relative limb length, and neurologic examination must be assessed. In addition, a careful examination of the hip includes assessment of gait, and precise documentation of range of motion. A patient must have at least 20–30° of hip abduction in order to undergo acetabular reorientation.

Plain radiographs

• Standard radiographs used in the evaluation of patients with acetabular dysplasia include anteroposterior (AP) pelvic (Fig. 1), frog-leg lateral (Fig. 2), false profile, and abduction and internal rotation views.

FIGURE 1

FIGURE 2

• The diagnosis of dysplasia is established based upon plain radiographs. The acetabular version may not be determined due to skeletal immaturity. Upper femoral dysplasia and epiphyseal morphology are assessed on both AP and frog-leg views. Hip joint congruity and concentricity are established based upon the AP and abduction and internal rotation radiographs.

Computed tomography (CT)

• Though not required for all patients, CT scanning can be useful to define acetabular anatomy in patients with neurologic or syndromic types of acetabular dysplasia, as nonstandard corrective maneuvering may be necessary during corrective surgery.

• CT scanning with three-dimensional modeling is most helpful in defining the region of acetabular insufficiency.

Arthrographic evaluation is still the most accurate diagnostic method to establish hip joint congruency, and may be necessary to determine the position of congruity, particularly when the femoral epiphysis is significantly deformed.

Improvements in magnetic resonance imaging (MRI) technology have enabled visualization of the acetabular labrum and articular cartilage. Although its role in the assessment of skeletally immature patients is evolving, MRI is useful if significant intra-articular abnormality is suspected based upon the clinical scenario.

Arthroscopic hip joint assessment can be useful either as a staging study to evaluate articular surfaces or for concomitant treatment of either labral or chondral pathology. The role of simultaneous arthroscopic treatment of labral pathology with correction of acetabular dysplasia remains to be studied.

Surgical Anatomy

Preservation of the triradiate cartilage involves careful dissection of the pubis and medial ischium as well as anatomic knowledge of the location of the triradiate cartilage on the medial ilium, ischium and pubis.

Positioning

The patient is positioned supine on a radiolucent operating table without a roll behind the ipsilateral pelvis in order to facilitate intraoperative evaluation of acetabular position (Fig. 3).

FIGURE 3

• Care is taken to ensure that the frontal plane of the pelvis is horizontal, and a postpositioning AP pelvis radiograph is obtained to establish a baseline with which intraoperative acetabular alignment can be compared.

• Positioning the contralateral arm over the chest on an armholder facilitates maneuvering of the fluoroscope.

The surgeon stands on the side of the operative hip and the assistant stands opposite. A fluoroscope is positioned opposite the surgeon with the monitor at the patient’s foot.

The entire leg, hip, abdomen, and lower chest are included in the surgical field so that exposure is not compromised following draping.

Following anesthetic induction, Foley catheterization is performed in order to protect the bladder during intrapelvic surgery.

Portals/Exposures

An oblique “bikini line” skin incision is made just distal to the anterior superior iliac spine.

The subcutaneous tissue is divided in line with the incision. The external oblique muscle fascia is exposed proximal to the incision, and a subcutaneous flap is elevated distally in order to expose the distal tensor fascia lata–sartorius interval (Fig. 4).

FIGURE 4

Procedure

Step 1: Superficial Dissection

The external oblique muscle fascia is incised laterally and the muscle is elevated from the iliac apophysis. The tensor-sartorius interval is opened longitudinally while protecting the lateral femoral cutaneous nerve.

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Tags: Operative Techniques Pediatric Orthopaedic Surgery

Jun 7, 2016 | Posted by admin in ORTHOPEDIC | Comments Off

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