Triple Innominate Osteotomy

 

 

 

 

DEFINITION

Triple innominate osteotomy (TIO) is a surgical procedure that includes osteotomy of the ilium, ischium, and pubis, allowing rotation of the acetabulum around the femoral head (FIG 1). This greater freedom of rotation allows it to be used in more severe cases where the Salter innominate osteotomy would not provide enough rotation to cover the femoral head.

Because the procedure does not damage the triradiate cartilage, it can be used in skeletally immature patients without the risk of disrupting acetabular growth. The volume of the acetabulum remains constant, but the weight-bearing surface is reoriented to improve femoral head coverage.

TIO is most commonly used for correction of acetabular dysplasia. Dysplasia may be a primary disorder or

result from incomplete treatment of developmental dysplasia of the hip (DDH).5 It is also seen as a result of neuromuscular conditions such as cerebral palsy, myelomeningocele, Down syndrome, Charcot-Marie-Tooth syndrome, etc.

TIO can also be used to improve coverage/containment of a malformed femoral head and for a combination

of acetabular and femoral head deformities such as in patients with Legg-Calvé-Perthes disease19 (Perthes disease), avascular necrosis (AVN), epiphyseal dysplasia, or an irregular femoral head resulting from a previous septic hip.

The TIO has the advantage of maintaining hyaline cartilage contact between the femoral head and

acetabulum.17 This is in contrast to other procedures sometimes used to correct severe hip dysplasia/instability (shelf procedure, Chiari osteotomy) which must rely on fibrocartilage to maintain a joint surface.

 

FIG 1 • A. 3-D representation of the iliac, ischial and pubic osteotomies. B. TIO allows rotation of the entire acetabulum around the femoral head without damage to the triradiate cartilage in the skeletally immature child.

 

 

 

ANATOMY

 

The acetabulum is formed by the ilium, ischium, and pubis, which in the immature pelvis are joined by the triradiate growth cartilage. This complex, triflanged growth center allows the acetabulum to grow properly, providing a deep, stable hip joint.

 

The femoral head should be covered by the roof of the acetabulum. The center-edge angle of Wiberg (angle between a line from the center of the femoral head to the lateral edge of the acetabular roof and a vertical line

drawn through the center of the femoral head) should be greater than 25 degrees.20

 

Lateral subluxation of the femoral head can be measured as the percent of the femoral head not covered by the acetabulum.

 

The acetabulum should be concave with a transverse sourcil (“eyebrow”—French) above the femoral head. Patients with hip dysplasia frequently have a very flat acetabulum with an up-turned sourcil. This results in shear forces on the joint that leads to early degenerative joint disease.

 

The normal hip joint has a spherical femoral head that is congruent with a well-formed acetabulum. Sphericity of the femoral head can be measured with Mose templates (concentric circles). Deformity in Perthes or AVN can be measured as a percentage of the femoral head (lateral pillar) that has collapsed when compared to the

contralateral side.7 Conditions that change femoral head sphericity lead to abnormal hip development and increased wear patterns within the joint.

 

PATHOGENESIS

 

Hip dysplasia: Many factors play a role in the etiology of hip dysplasia. The high concordance between twins and studies noting that babies with parents or siblings with dysplasia have a much higher DDH incidence than

the general population confirm a genetic component. Mechanical factors also contribute to the risk for dysplasia. First babies and babies that are large have a higher risk thought to be secondary to inadequate space in the uterus during development. There also appears to be a hormonal component, as females and babies with increased joint laxity are at greater risk of hip dysplasia.

 

Legg-Calvé-Perthes disease: The etiology of Perthes disease remains obscure and can be thought of as idiopathic AVN of the hip in childhood. Some have postulated a deficiency in protein C leading to a

hypercoagulable state with thrombosis triggered by prothrombotic insults.11

 

As most Perthes patients have a delayed bone age, some have suggested that Perthes may represent a form of epiphyseal

 

P.913

dysplasia. Delayed skeletal maturation, is a routine finding in a typical Perthes case. The delay in maturation of the femoral head preossific nucleus may not adequately protect the vessels that ascend the femoral neck to the epiphysis, predisposing to AVN.

 

 

 

FIG 2 • A. AP and frog view of the pelvis in a 10-year-old girl with bilateral hip dysplasia. She was most symptomatic on the right. B. AP and lateral image of 3-D CT study of the right hip.

 

NATURAL HISTORY

 

Hip dysplasia

 

 

Untreated hip dysplasia is the leading cause of premature hip arthritis that results in early total hip replacement.

 

Abnormal sheer stresses on the hip lead to early osteoarthritis, and the more severe the dysplasia, the more likely the development of arthritis (FIG 2).

 

Legg-Calvé-Perthes disease

 

 

The natural history for younger patients (younger than age 8 years at onset) and patients with milder disease (Herring A classification) is more benign with little long-term disability.

 

Children who are older at onset and who have more severe disease (Herring B or C classification) are more likely to develop femoral head deformity which predisposes to early osteoarthritis.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Hip dysplasia

 

Hip dysplasia is often asymptomatic in childhood and adolescence. Patients may have decreased abduction on examination or pain with internal rotation of the hip.

 

 

 

FIG 3 • A. AP and frog view of a 7-year-old boy with severe left Legg-Calvé-Perthes disease with subluxation and lateral extrusion despite prior attempts to treat with conservative methods including Petrie casts. B. Dynamic arthrogram of left hip showing femoral head deformity. C. MRI study of pelvis showing marked femoral head extrusion of the left hip.

 

 

When symptoms are present, they are likely due to increased shear stresses, labral damage, and later to osteoarthritis. The pain is usually groin pain rather than lateral or trochanteric pain.

 

Legg-Calvé-Perthes disease

 

 

Perthes may present as hip or knee pain. Early pain may be episodic.

 

Patients with severe disease may have subluxation and more severe pain. A Trendelenburg gait is often noticed.

 

Decreased abduction can be mild or severe. A marked loss of abduction with the hip in the fully extended position (pelvis rotates rather than hip abducting) suggests hinge abduction and is a bad prognostic sign.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs: Anteroposterior (AP) and frog lateral views provide two orthogonal views of the femoral head. However, to get two views of the acetabulum, a false-profile x-ray should be taken in addition to the AP view (FIG 3A). Always image both hips (to allow comparison).

 

We advise a surgeon performed arthrogram to evaluate the hip deformity and to assess for hinge abduction as well as the desired limb position following surgical correction (FIG 3B).

 

Three-dimensional (3-D) computed tomography (CT) scans with reconstructions provide a better understanding of pathologic bony anatomy.2

 

Magnetic resonance imaging (MRI) with arthrogram helps to evaluate the labrum and joint space (FIG 3C).

 

 

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DIFFERENTIAL DIAGNOSIS

Hip dysplasia DDH

Dysplasia secondary to neuromuscular disease (cerebral palsy, myelomeningocele, Charcot-Marie-

Tooth disease, etc.)

Dysplasia, subluxation secondary to syndromes (Down syndrome)

 

Legg-Calvé-Perthes disease

AVN secondary to Perthes disease

AVN secondary to steroid use, chemotherapy, metabolic disruption, infection, sickle cell disease Epiphyseal dysplasia with poor femoral head coverage

 

 

NONOPERATIVE MANAGEMENT

 

Hip dysplasia

 

 

From infancy to childhood (up to 18 months of age), if the hip is located within a dysplastic acetabulum, a Pavlik harness or abduction orthosis can be worn to treat the dysplasia.3

 

From age 18 months to 5 years, abduction bracing has not been found to predictably improve dysplasia, although nighttime brace use is occasionally recommended. Most advise monitoring during this period with

hope that the acetabular growth centers will mature and correct the dysplasia.14

 

Older children with hip dysplasia are typically asymptomatic until the hip begins to have degenerative changes or a labral tear. Anti-inflammatory medications and activity modification can be used to decrease pain, but these do not correct the underlying problem, and by masking symptoms may delay surgical correction.

 

Legg-Calvé-Perthes disease

 

 

Children younger than 8 years and patients with hips classified as Herring A can be treated conservatively with predictable results. Conservative treatment includes activity modification and observation, abduction exercises, abduction bracing, and percutaneous adductor longus lengthening followed by Petrie casting (FIG 4) or bracing to maintain abduction.

 

 

 

FIG 4 • Petrie casts, which provide containment of the femoral head, are often used in patients with Perthes

disease in preparation for TIO.

 

 

Older children and those with Herring B and C hips require prolonged Petrie casting or bracing (rarely practiced) or surgical containment.

 

SURGICAL MANAGEMENT

 

Hip dysplasia

 

 

Dysplasia before age 4 years is treated nonoperatively unless the hip is dislocated and requires open reduction or the dysplasia is very severe.

 

Patients aged 4 to 10 years can be treated with an acetabular redirecting osteotomy16 or an osteotomy that bends through the triradiate cartilage.12

 

From the age of about 10 years until triradiate cartilage closure, a TIO is preferred for correction of dysplasia. Once the triradiate cartilage closes, TIO can still be performed but a periacetabular osteotomy may be

 

preferred because the posterior column remains intact, providing greater stability and earlier weight bearing.4 Legg-Calvé-Perthes disease

 

Children older than age 6 to 8 years or with more severe disease can be treated with a variety of surgical procedures aimed at containing the capital femoral epiphysis during the early fragmentation phase when the biologically plastic femoral head is at risk for subluxation, hinge abduction, and the development of permanent femoral head deformity. The simplest surgical treatment is adductor lengthening followed by Petrie casting or bracing. This can be used alone for very mild cases or in preparation for containment surgery.

 

Formal containment procedures include varus proximal femoral osteotomy designed to direct the capital

femoral epiphysis into the acetabulum. A Salter innominate osteotomy can also be performed, but Rab15 has clarified that the degree of acetabular rotation achieved with the Salter procedure is often not enough to cover the femoral head in more severe Perthes disease. A combined femoral and Salter procedure may be a better choice.

 

TIO, which rotates the entire acetabulum around the femoral head, allows containment in more severe

cases18 while avoiding the problems of femoral osteotomy (limp, limb shortening). A shelf (labral support) osteotomy or Chiari procedure may be a better choice for a severely deformed femoral head that cannot be congruently centered in the acetabulum.

 

Preoperative Planning

 

Hip dysplasia

 

 

Radiographs and a 3-D CT scan (if available) helps to better understand the nature and location of the acetabular deficiency.

 

 

Typical dysplasia patients have an anterolateral deficiency.

 

Children with neuromuscular disorders such as cerebral palsy, due to muscle imbalance around the hip joint and flexion contracture, often have a posterior deficiency.8

 

Once the amount and direction of dysplasia has been determined, acetabular rotation can be planned.

 

 

 

One should avoid overrotating the acetabulum, as this can cause anterolateral impingement. Also, external rotation of the acetabulum should be avoided to prevent the creation of acetabular

retroversion (which in itself can predispose to hip arthritis).

 

 

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Legg-Calvé-Perthes disease

 

 

A preoperative dynamic arthrogram provides information about how to best contain the femoral head. We perform an arthrogram and percutaneous adductor lengthening followed by Petrie casting (for 6 weeks) prior to definitive containment surgery.

 

Positioning

 

The patient is positioned supine on a radiolucent table (FIG 5). A Foley catheter can be considered to minimize any risk for bladder injury with the pubic ramus cut.

 

A sandbag bolster is placed under the trunk to tip the patient toward the opposite side giving better exposure of the hip laterally. Avoid placing the bolster directly behind the pelvis because it often distorts the image intensifier views.

 

The leg is draped free, and the abdomen is prepped past the midline medially, to just below the nipple level superiorly, and around the buttock posteriorly. The ischial tuberosity must be kept in the surgical field.

 

The C-arm and screen of the image intensifier are positioned to allow a clear view for the surgeon.

 

 

 

FIG 5 • Patient position on operating table for TIO.

 

TECHNIQUES

• Exposure

TIO (TECH FIG 1A) is generally performed through two incisions, one anterolateral and a second medial incision in the adductor (groin) area. However, three smaller incisions can be considered to allow a more precise exposure for each osteotomy cut, especially in larger patients.

 

 

 

 

TECH FIG 1 • A. The first cut is the iliac cut. B. Lateral view of the right hip showing that the incision is made just below the iliac crest, as for a Salter osteotomy.

 

 

The first incision is below the iliac crest as for a Salter osteotomy (TECH FIG 1B). The second incision is distal to the groin crease, slightly below the superior pubic ramus, lateral to the adductor longus tendon origin, and medial to the femoral neurovascular bundle. The pubic osteotomy is performed through this medial incision with the ischial osteotomy also possible with posterior extension of the incision.

• Making the Bony Cuts

Iliac Osteotomy

 

After making the anterolateral incision (TECH FIG 2A), the cartilaginous iliac crest apophysis is split, starting at the anterior superior iliac spine (ASIS) and continuing posteriorly for 6 to 8 cm. With care, this cartilage splitting can be carried anteriorly down to the anterior inferior iliac spine (AIIS).

 

Both sides of the iliac wing are exposed subperiosteally down to the sciatic notch using a Cobb periosteal elevator. Specially designed Rang retractors (Jantek Engineering, Inc., Paso Robles, CA) can be placed in the sciatic notch to improve exposure (TECH FIG 2B) and a Gigli flexible wire saw passed through the notch (TECH FIG 2C).

 

The iliac osteotomy is then performed by bringing the Gigli saw anteriorly through the ilium, exiting at a point just above the AIIS. In older, larger patients, we make this cut slightly more proximal than in a Salter osteotomy, which allows room to place a temporary Schanz screw to guide the acetabular segment.

 

P.916

 

 

 

TECH FIG 2 • Lateral view of the right hip. A. The iliac crest apophysis is split to expose the medial and lateral aspects of the ilium down to the sciatic notch. B. Rang retractors are placed in the sciatic notch to facilitate passing the Gigli saw. C. A Gigli saw is passed through the sciatic notch and is brought through the ilium to create the osteotomy.

Psoas Intramuscular Lengthening at the Pelvic Brim

 

At the distal end of the Salter incision, the structures are retracted on the medial side of the pelvic brim. The iliopsoas muscle is identified and rotated to expose the psoas tendon which lies posteriorly and medially in relation to the muscle mass of the iliopsoas.

 

Because the femoral nerve lies just anterior to the psoas muscle, care should be taken to be certain that you have identified the psoas tendon. A right angle hemostat can then be placed around the tendon and the tendon is sectioned leaving the muscle belly intact. This allows an intramuscular lengthening.

 

The Salter incision can now be packed with a damp sponge and the wound edges pulled together with a towel clip, whereas the other osteotomies are completed.

Pubic Osteotomy

 

Earlier descriptions of TIO technique advised that the superior pubic ramus be cut from the anterolateral Salter incision.

 

We initially used this but then changed to performing the pubic cut through the medial incision which makes exposure easy, avoiding risk to the neurovascular bundle due to over-retraction with the anterolateral approach (TECH FIG 3A).

 

A 4-cm transverse incision (parallel to the inguinal ligament) is made just lateral to the adductor longus origin and 2 cm distal to the groin crease.

 

This incision can then be extended medially and distally to allow subsequent exposure of the ischium (TECH FIG 3B).

 

The pectineus muscle is identified just lateral to the adductor longus origin and is partially elevated off of the superior pubic ramus (TECH FIG 3C). The saphenous vein, which often crosses the field, should be identified and retracted laterally. The pubic

 

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ramus is identified, and Hohmann retractors are placed above and below the pubis extraperiosteally.

 

 

 

 

TECH FIG 3 • A. The second cut is the superior pubic ramus cut. B,C. Medial views of the right groin area.

B. The incision for the pubic cut is made distal to the groin crease. S.P.R., superior pubic ramus; I.T., ischial tuberosity. (continued)

 

 

 

TECH FIG 3 • (continued) C. After elevating the medial border of the pectineus off the pubic ramus, Hohmann retractors are placed above and below the pubis extraperiosteally. D. Intraoperative radiograph showing appropriate site for pubic osteotomy.

 

 

Those new to the operation might be advised to begin with a subperiosteal approach to the pubic ramus.

 

Use fluoroscopy to confirm your retractor placement before making the osteotomy. The closer you are to the acetabulum, the easier it will be to rotate the acetabulum (TECH FIG 3D).

 

Once position is confirmed, one can use a narrow rongeur or osteotome to make the pubic cut.

 

The cut can be angled slightly to allow subsequent superomedial acetabular displacement.

 

If a rongeur is used (the safest method), the bits of excised bone should be maintained and returned to the osteotomy site to avoid the risk for pseudarthrosis.

Ischial Osteotomy

 

The 3-D nature of the ascending ischium, buried deeply in muscle, is not easy to comprehend.

 

When first performing this procedure, you should have a skeletal model of the pelvis in the operating room and the circulating nurse should hold it for you to inspect as needed (TECH FIG 4A).

 

 

 

TECH FIG 4 • A. The third cut is the ischial cut. B-D. Medial views of the right ischial exposure. B. Two Hohmann retractors are placed around the ischium. Tapping the retractors with a mallet helps to get them positioned. C. A third sharp Hohmann is driven into the ischium in the proximal end of the wound (just below the acetabulum) to help with retraction. The osteotome can then be introduced. D. When the osteotome enters the posterior cortex, it is rotated medially to displace the ischium. (continued)

 

 

P.918

 

 

 

TECH FIG 4 • (continued) E,F. Illustrations of the effective rotational maneuver described in D. In this right hip, after the ischium has been completely cut, the osteotome is rotated in a clockwise manner medially to displace the iliac bone just below the acetabulum. This aids in placing the femoral head in an ideal biomechanical circumstance when performing TIO.

 

 

The proximity of the ischial spine to the sciatic nerve must be appreciated. After full exposure of the ischium, external rotation of the femur may help to avoid injury to the sciatic nerve during the ischial osteotomy.

 

Through the adductor incision, blunt dissection is carried out subcutaneously down to the ischial spine (TECH FIG 4B).

 

The electrocautery is used to take down the posterior portion of the adductor magnus muscle origin just anterior and medial to the proximal origin of the hamstrings.

 

The ischial tuberosity is identified, and an initial sharp Hohmann retractor is placed inside the obturator foramen. A Cobb elevator is used to clear the ischium up to its origin just below the acetabulum.

 

Blunt Hohmann retractors are then placed extraperiosteally around the ischium with one retractor in the obturator foramen and the other lateral to the ischium.

 

Using a mallet to tap a blunt Hohmann into these spaces makes it easier (helps to safely elevate the thick periosteum and tendon origins). (This is a very deep exposure and the neophyte will be surprised at the depth of the ascending ischium.)

 

Finally, a third Hohmann retractor (sharp) is driven into the ischial bone just below the acetabulum to allow easier superior retraction (TECH FIG 4C). Thus, a total of three Hohmann retractors— one medial, one lateral, and a sharp-tipped—tapped into the bone proximally.

 

Fluoroscopy is used to check position. The ischial cut should be just below but not in the acetabulum (about 1 cm below the lower end of the “teardrop”).

 

Once position is confirmed, a rongeur can be used to start the osteotomy creating a groove for the osteotome to prevent the osteotome from slipping.

 

A long, straight osteotome is then inserted and used to complete the osteotomy.

 

To confirm completion and begin displacement of the osteotomy, the large wooden handle of the osteotome is used to radically rotate the acetabular segment medially before the osteotome is withdrawn.

 

This begins the desired medial displacement of the ischium (TECH FIG 4D).

 

Using a very long (approximately 20 inch) wooden handled osteotome makes this essential rotational maneuver easier (TECH FIG 4E,F).

 

 

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• Rotation of the Acetabulum

   

  The packing sponges are now removed from the Salter incision.

   

  A temporary Schanz screw is placed in the acetabular segment just above the hip joint to use as a handle to guide acetabular positioning (TECH FIG 5A).

   

  A long ballpoint pusher is placed in the superior pubic ramus just lateral to the pubic cut and impacted into the bone via the medial incision (TECH FIG 5B).

   

  This is pushed upward and inward, whereas the Schanz screw is levered downward and laterally to rotate the entire acetabulum around the femoral head (TECH FIG 5C).

   

   

   

  TECH FIG 5 • A. Lateral view of the right hip. A Schanz screw is placed just above the hip (arrow); it can be used as a lever to help rotate the acetabulum. B. A ballpoint pusher can be used to push the pubic

  portion upward and inward, whereas the Schanz screw levers the superior acetabulum anterolaterally.

  C. Fluoroscopic image showing ballpoint pusher (white arrow) and Schanz screw (black arrow). D,E.

  Lateral views show bone graft taken from the iliac crest and fashioned to fit into the iliac osteotomy.

   

   

  A Cobb elevator is placed posteriorly in the Salter (iliac) cut and rotated to encourage lateral positioning of the acetabular fragment in the coronal plane.

   

  A wedge of bone is removed from the iliac crest using an oscillating saw. The base of the wedge should be fashioned to fit tightly in the gap of the iliac osteotomy (TECH FIG 5D).

   

  This triangular graft needs to be only about half as large as in a Salter osteotomy for the same size patient because a good deal of the rotation should have occurred through the pubic and ischial cuts (TECH FIG 5E).

• Temporary Fixation

   

  The osteotomy is first fixed with temporary smooth K-wires.

   

  Acetabular position is checked with fluoroscopy to confirm the amount of coverage that has been obtained (TECH FIG 6A).

   

  Be careful not to overrotate anteriorly (producing anterior impingement), which is indicated by a crossover sign and an overly prominent ischial spine on the radiograph (TECH FIG 6B).

   

  A well-performed TIO (TECH FIG 6C) should have these x-ray features:

   

  Ilium: The acetabular segment should be positioned 8 to 10 mm lateral to the inner wall of the ilium above.

   

   

   

  Pubis: The acetabular segment should be displaced slightly superior and medial. Approximately 50% step-off of the ischial cut with the proximal portion moving superomedially. Teardrop angled about 20 degrees (vertical prior to rotation)

   

   

  The ischial spine should be only a little (if any) more prominent than on the opposite side. Sourcil: in a transverse position

   

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  TECH FIG 6 • A. The osteotomy is temporarily fixed using smooth K-wires to confirm position with fluoroscopy before final screw fixation. B. This acetabulum has been rotated too far anteriorly and laterally. Note the prominent ischial spine and crossover sign. C. Radiographic features of an ideal TIO. A: The acetabular segment of the ilium should be positioned 8 to 10 mm lateral to the inner wall of the ilium above. B: The acetabular segment of the pubis should be displaced slightly superior and medial. C: About 50% step-off of the ischial cut with the proximal segment displaced medially. D: Teardrop is angled about 20 degrees (vertical before rotation). E: The ischial spine should be only a little (in any) more prominent than on the opposite side. F: The sourcil is in a transverse position.

   

• Fixation

   

  4.5-mm fully threaded screws can be inserted from the iliac crest across the bone graft and into the superior acetabular bone.

   

  Using fully threaded screws minimizes the tendency for loss of correction which can occur when a partially threaded screw is tightened too much, overcompressing the graft and pulling the acetabular edge upward.

  Instead, the screws should stabilize and maintain some distraction.21

   

  We use two or three screws to adequately fix the acetabular fragment. Threaded K-wires can be used in smaller patients where the bone may not be thick (strong) enough to hold the 4.5-mm screw.

   

  In older, larger patients, we often place an additional single screw from medial to lateral across the pubic osteotomy to prevent further rotation of the acetabular fragment or nonunion of the pubis (TECH FIG 7).

   

  Any remaining bone graft fragments can be packed into the pubic and ischial osteotomies to prevent nonunion.

   

   

   

  TECH FIG 7 • Supplementation of the iliac screw fixation with a pubic fixation screw.

   

• Wound Closure

   

  After thorough irrigation, the iliac crest apophysis is reapproximated and closed with a running absorbable suture.

   

  Hemovac drains are placed in the Salter, pubic, and ischial incisions.

   

  The incisions are then closed in layers with absorbable suture followed by sterile dressings. In most cases, a single hip spica is applied.

   

  If both iliac and pubic fixation is secure in a cooperative patient, we sometimes use no formal postoperative immobilization.

   

   

  P.921

   

  PEARLS AND PITFALLS
  	Preoperative ▪ A dynamic arthrogram is the best way to determine hip joint function, mobility, and

   

  arthrogram stability. The study also allows visualization of the labrum and possible impingement of the femoral neck on the labrum or acetabulum.

   

  Pubic osteotomy

  • Performing the pubic osteotomy through the medial incision makes exposure easier and avoids risk to the neurovascular bundle due to overretraction with the anterolateral approach.

  • Extraperiosteal exposure of the pubis allows easier periosteal sectioning because the periosteum is strong in this area and may prevent movement of the pubic segment. Care must be taken to avoid the obturator nerve which courses just below the superior pubic ramus.

     

    Ischial osteotomy

  • When trying to palpate the ischium, the femur should be internally rotated to avoid erroneously palpating the greater trochanter which can be in close proximity to the ischium. Once the bony prominences have been identified, external rotation of the femur should protect the sciatic nerve during the ischial osteotomy.

  • To confirm completion of the ischial osteotomy, the osteotome is used to radically rotate the acetabular segment medially. This begins the desired medial displacement of the ischial segment that is attached to the acetabulum.

     

    Rotation of the acetabular fragment

  • Care must be taken to not externally rotate the acetabular fragment (this is easy to do in a triple osteotomy and will cause undesired acetabular retroversion). A temporary Schanz screw can help to control acetabular position. To avoid undesirable external rotation, Salter's advice was that “even after the osteotomy is performed the anterior superior and anterior inferior iliac spines should remain aligned.”

     

    Fixation of the osteotomy

  • Fully threaded screws should be used to stabilize the acetabular fragment and maintain some distraction. This minimizes the tendency for loss of correction which can occur when a partially threaded screw is tightened too much, overcompressing the graft and pulling the acetabular edge upward.

 

POSTOPERATIVE CARE

 

The single-leg spica cast is maintained for 4 to 6 weeks followed by partial weight bearing with crutches for an additional 4 weeks. If adequate bone healing is noted on x-ray, activity can then be advanced as tolerated.

 

Physical therapy may be useful for regaining abductor strength and motion.

 

The fixation screws can be removed 6 to 12 months postoperatively is desired.

OUTCOMES

As TIO is most commonly used for late juveniles, adolescents, and young adults, very long-term follow-up studies are required to evaluate function over a lifetime, with 30 to 60 years of follow-up. Unfortunately, these long-term studies have not yet been done. There are several studies that look at short- to medium-term results.

Guille et al6 reported more than 10-year follow-up of 11 patients ages 11 to 16 years with symptomatic hip dysplasia treated with TIO, 10 hips improved radiographically, 8 improved functionally, 1 required a total

 

 

hip arthroplasty.

Faciszewski et al1 followed 56 hips in 44 patients that underwent TIO for 2 to 12 years.

Improvement in pain and function was considered good in 53 hips. Three hips were considered failures.1

Peters et al13 evaluated 60 hips in 50 patients who underwent TIO.

At average 9-year follow-up, 12 (20%) hips had been converted to total hip arthroplasty and 4 (7%) hips had incapacitating pain.

Radiographically, there was significant improvement in the center-edge angle of Wiberg and the acetabular angle of Sharp.

There also was a statistically significant relationship between failure of the osteotomy and severity of preexisting hip arthrosis.13

In patients with acetabular dysplasia, indications and outcomes are better understood. Application of TIO for patients with femoral deformity (Perthes, AVN, epiphyseal dysplasia) has a shorter track record but appears to provide clear benefit in properly selected cases.9, 10

 

COMPLICATIONS

Pubic or ischial osteotomy nonunion

Overcorrection of the acetabular fragment resulting in iatrogenic impingement Retroversion of the acetabular fragment

Sciatic or obturator nerve injury Loss of fixation or correction

 

 

REFERENCES

1. Faciszewski T, Coleman SS, Biddulph G. Triple innominate osteotomy for acetabular dysplasia. J Pediatr Orthop 1993;13:426-430.

    

    

2. Frick SL, Kim SS, Wenger DR. Pre- and postoperative three-dimensional computed tomography analysis of triple innominate osteotomy for hip dysplasia. J Pediatr Orthop 2000;20:116-123.

    

    

3. Gans I, Flynn JM, Sankar WN. Abduction bracing for residual acetabular dysplasia in infantile DDH. J Pediatr Orthop 2013;33:714-718.

    

    

4. Ganz R, Klaue K, Vinh TS, et al. A new periacetabular osteotomy for the treatment of hip dysplasias: technique and preliminary results. Clin Orthop Relat Res 1988;(232):26-36.

    

    

5. Gillingham BL, Sanchez AA, Wenger DR. Pelvic osteotomies for the treatment of hip dysplasia in children and young adults. J Am Acad Orthop Surg 1999;7:325-337.

    

    

6. Guille JT, Forlin E, Kumar SJ, et al. Triple osteotomy of the innominate bone in treatment of developmental

   dysplasia of the hip. J Pediatr Orthop 1992;12:718-721.

    

    

7. Herring JA, Kim HT, Browne R. Legg-Calve-Perthes disease. Part II: prospective multicenter study of the effect of treatment on outcome. J Bone Joint Surg Am 2004;86-A:2121-2134.

    

    

   P.922

    

8. Kim HT, Wenger DR. The morphology of residual acetabular deficiency in childhood hip dysplasia: three-dimensional computed tomographic analysis. J Pediatr Orthop 1997;17:637-647.

    

    

9. Kumar D, Bache CE, O'Hara JN. Interlocking triple pelvic osteotomy in severe Legg-Calve-Perthes disease. J Pediatr Orthop 2002;22:464-470.

    

    

10. Kumar SJ, MacEwen GD, Jaykumar AS. Triple osteotomy of the innominate bone for the treatment of congenital hip dysplasia. J Pediatr Orthop 1986;6:393-398.

     

     

11. Mehta JS, Conybeare ME, Hinves BL, et al. Protein C levels in patients with Legg-Calve-Perthes disease: is it a true deficiency? J Pediatr Orthop 2006;26:200-203.

     

     

12. Pemberton PA. Pericapsular osteotomy of the ilium for the treatment of congenitally dislocated hips. Clin Orthop Relat Res 1974;(98):41-54.

     

     

13. Peters CL, Fukushima BW, Park TK, et al. Triple innominate osteotomy in young adults for the treatment of acetabular dysplasia: a 9-year follow-up study. Orthopedics 2001;24:565-569.

     

     

14. Ponseti IV. Growth and development of the acetabulum in the normal child. Anatomical, histological, and roentgenographic studies. J Bone Joint Surg Am 1978;60:575-585.

     

     

15. Rab GT. Containment of the hip: a theoretical comparison of osteotomies. Clin Orthop Relat Res 1981; (154):191-196.

     

     

16. Salter RB, Dubos JP. The first fifteen year's personal experience with innominate osteotomy in the treatment of congenital dislocation and subluxation of the hip. Clin Orthop Relat Res 1974;(98):72-103.

     

     

17. Steel HH. Triple osteotomy of the innominate bone. J Bone Joint Surg Am 1973;55:343-350.

     

     

18. Wenger DR, Pandya NK. Advanced containment methods for the treatment of Perthes disease: Salter plus varus osteotomy and triple pelvic osteotomy. J Pediatr Orthop 2011;31(2 suppl):S198-S205.

     

     

19. Wenger DR, Pring ME, Hosalkar HS, et al. Advanced containment methods for Legg-Calve-Perthes disease: results of triple pelvic osteotomy. J Pediatr Orthop 2010;30:749-757.

     

     

20. Wiberg G. Shelf operation in congenital dysplasia of the acetabulum and in subluxation and dislocation of the hip. J Bone Joint Surg Am 1953;35:65-80.

     

     

21. Yassir W, Mahar A, Aminian A, et al. A comparison of the fixation stability of multiple screw constructs for two types of pelvic osteotomies. J Pediatr Orthop 2005;25:14-17.