Dennis R. Wenger and Maya E. Pring
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 cases (more severe dysplasia, older children) when 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. Acetabulum size is maintained and redirected around the femoral head; the volume of the acetabulum remains constant but the weight-bearing surface is increased with improved femoral head coverage.
The TIO, often used for severe dysplasia, has the advantage of maintaining hyaline cartilage contact between the femoral head and acetabulum. This is in contrast to other procedures sometimes used to correct severe hip dysplasia or instability (shelf procedure, Chiari osteotomy) that must rely on repair tissue (fibrocartilage) to maintain a joint surface.
TIO is most commonly used for correction of acetabular dysplasia. Dysplasia may be a primary disorder or may result from incomplete treatment of developmental dysplasia of the hip (DDH); it is also seen as a result of neuromuscular conditions such as cerebral palsy, myelomeningocele, Down syndrome, and Charcot-Marie-Tooth syndrome.
TIO is also used to improve coverage and containment of a malformed femoral head, and for a combination of acetabular and femoral head deformities. Patients with Legg-CalvéPerthes disease (Perthes disease), avascular necrosis (AVN), epiphyseal dysplasia, or an irregular femoral head resulting from a previous septic hip may also have poor femoral head coverage or dysplasia and benefit from TIO.
FIG 1 • Triple innominate osteotomy 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 (FIG 2A,B). This complex, triflanged growth center allows the acetabulum to grow properly, providing a deep, stable hip joint. Injury to the triradiate cartilage by either fracture or an inappropriate acetabular osteotomy can alter the normal growth process, leading to hip dysplasia and subluxation.
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 more than 25 degrees (FIG 2C).
Lateral subluxation of the femoral head can be measured as the percentage of the femoral head not covered by the acetabulum.
The acetabulum should be concave with a transverse sourcil (“eyebrow” in French) that turns down around the femoral head. Patients with hip dysplasia frequently have a very flat acetabulum with an upturned sourcil. This results in shear forces on the joint, leading 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 disease or AVN can be measured as a percentage of the femoral head (lateral pillar) that has collapsed when compared to the contralateral side.9,10
Conditions that change femoral head sphericity lead to abnormal hip development and increased wear patterns within the joint (FIG 2D).
PATHOGENESIS
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. Hip dysplasia is also commonly associated with torticollis and metatarsus adductus, with each of the three abnormalities thought to be a “packaging” problem.
There also appears to be a hormonal component, as girls and babies with increased laxity are at higher risk of hip dysplasia.
FIG 2 • Lateral (A) and medial (B) view 3D CT scans of an immature acetabulum with femur subtracted show that the triradiate cartilage is a growth center of the acetabulum that contributes to the ilium, ischium, and pubis. C. The center–edge (CE) angle of Wiberg is the angle created by a vertical line through the center of the femoral head and a line from the lateral edge of the acetabular roof to the center of the head. The normal hip on the left has a CE angle of 35 degrees; the dysplastic hip on the right has a CE angle of 15 degrees. D. Loss of sphericity of the left femoral head after reossification of Perthes disease has led to a noncongruent joint (left hip).
Legg-Calvé-Perthes Disease
The cause of Perthes disease remains obscure, and it still can be thought of as idiopathic AVN of the hip in childhood.
A few studies have shown a possible association between passive smoking and Perthes disease.7,16
Others have postulated that a deficiency in protein C leads to a hypercoagulable state, with thrombosis triggered by prothrombotic insults such as passive smoking.17
Because most Perthes patients have a delayed bone age, some have suggested that Perthes may represent a form of epiphyseal 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.
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 (OA), and the more severe the dysplasia, the more likely the development of arthritis.
Legg-Calvé-Perthes Disease
The natural history for younger patients (under age 8 years at onset) and patients with milder disease (Herring A classification) is more benign, with minimal 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 OA.
PATIENT HISTORY AND PHYSICAL FINDINGS
Hip Dysplasia
Acetabular dysplasia is often asymptomatic in childhood and adolescence.
Patients may have decreased abduction on examination, or pain with internal rotation of the hip. When they are present, symptoms are likely due to increased shear stresses, to labral damage, and later to OA.
The pain is usually groin pain rather than lateral or trochanteric pain.
Legg-Calvé-Perthes Disease
The disease may present as hip or knee pain.
Early pain may be episodic.
Patients with severe disease have 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 poor prognostic sign.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Anteroposterior (AP) plus frog-leg lateral plain radiographs provide two orthogonal views of the femoral head. However, to get two views of the acetabulum, a false profile radiograph should be taken in addition to the AP view. Both hips should always be imaged to allow comparison (FIG 3A–C).
A dynamic arthrogram is the best way to determine the function and motion of the joint, since it allows visualization of the labrum and impingement of the femoral neck on the labrum or acetabulum. We advise a surgeon-performed arthrogram to evaluate the hip deformity and to assess for hinge abduction as well as the desired limb position after surgical correction (FIG 3D,E).
Three-dimensional CT scans with reconstructions provide a better understanding of pathologic bony anatomy (FIG 3F).
MRI with arthrogram helps to evaluate the labrum and joint space (FIG 3G).
FIG 3 • A,B. AP and frog-leg lateral radiographs of the pelvis show two views of the proximal femur but not of the acetabulum. C. To get another view of the acetabulum, a false profile view is obtained. Arthrogram (D) shows impingement in the abduction view (E). F. 3D CT scan clearly shows some dysplasia plus subluxation of the left hip. G. An MRI is the best study for evaluating labral tears (superolateral labral tear shown).
DIFFERENTIAL DIAGNOSIS
Dysplasia secondary to DDH
Dysplasia secondary to neuromuscular disease (eg, cerebral palsy, myelomeningocele, Charcot-Marie-Tooth disease)
Dysplasia, subluxation secondary to syndromes (Down syndrome)
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.
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.21
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. Therefore, medications should not be used for more than a short time. Instead, surgical correction should be performed to cover the femoral head and restore normal biomechanical forces.
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
Percutaneous adductor longus lengthening followed by Petrie casting or bracing to maintain abduction (FIG 4)
FIG 4 • Petrie casts, which provide containment of the femoral head, are often used in patients with Perthes disease before triple innominate osteotomy or occasionally for nonoperative treatment.
Older children and those with Herring B and C hips require prolonged Petrie casting (rarely practiced) or surgical containment.
SURGICAL MANAGEMENT
General Principles
Hip Dysplasia
Children under age 5 years can be treated nonoperatively unless the hip is dislocated and requires open reduction, or the dysplasia is very severe.
Patients age 5 to 10 can be treated with an acetabular redirecting osteotomy that bends through the triradiate cartilage (Pemberton osteotomy, Chap. PE-71) or rotates through the pubic symphysis (Salter innominate osteotomy, Chap. PE-70).
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, allowing earlier weight bearing.5
Legg-Calvé-Perthes Disease
Perthes disease can be treated nonoperatively in young children.
Children older than 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 phase of reossification 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. Adductor lengthening and Petrie casting improves mobility of the hip and returns the hip to a more congruous, contained position, beginning the remolding process that surgical containment will continue.
Formal containment procedures include varus proximal femoral osteotomy (see Chap. PE-27) designed to direct the capital femoral epiphysis into the acetabulum.
A Salter innominate osteotomy can also be performed, but Rab22 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 cases while avoiding the problems of femoral osteotomy (limp, limb shortening). This procedure has the benefit of maintaining hyaline cartilage surface-to-surface contact (as compared to the shelf or Chiari procedure).
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. With these procedures, contact between the hyaline (head) and hyaline cartilage (acetabulum) is partially sacrificed.
Preoperative Planning
Hip Dysplasia
Radiographs and a 3D CT scan (if available) help in better understanding 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.1,12,13
Once the amount and direction of dysplasia have been determined, acetabular rotation can be planned.
Overrotation of the acetabulum should be avoided, as this can cause anterolateral impingement, which may hasten degenerative changes.
Also, external rotation of the acetabulum should be avoided to prevent the creation of acetabular retroversion (which in itself can predispose to hip arthritis).
Legg-Calvé-Perthes Disease
A preoperative dynamic arthrogram is the best study for understanding how to best contain the femoral head. We perform an arthrogram and percutaneous adductor lengthening followed by Petrie casting (for 6 weeks) before definitive containment surgery.
Positioning
The patient is positioned supine on a radiolucent table. A Foley catheter can be considered to minimize any risk for bladder injury with the pubic ramus cut. This is advised for a surgeon's initial cases but is often not needed once experience has been gained.
A sandbag bolster is placed under the trunk to tip the patient toward the opposite side, giving better exposure of the hip laterally. The bolster should not be placed directly behind the pelvis because it often distorts the image intensifier views.
The leg is draped free and the abdomen is prepared 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 (FIG 5).
FIG 5 • Patient position on operating table for triple innominate osteotomy.
The C-arm and screen of the image intensifier are positioned to allow a clear view for the surgeon.
Approach
TIO can be performed through two or three incisions. Using three incisions allows more precise exposure for each osteotomy cut, especially in larger patients.
The first incision is below the iliac crest as for a Salter osteotomy.
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 neurovascular bundle. The pubic osteotomy is performed through this incision with the ischial osteotomy also possible with posterior extension of the incision.
The third incision (if the surgeon chooses a three-incision approach) is longitudinal, distal to the gluteal crease, and just medial to the ischial spine with the hip flexed to 90 degrees.
TECHNIQUES
ILIAC OSTEOTOMY
An 8- to 10-cm Salter-type incision is made 1 cm below the iliac crest (TECH FIG 1A,B).
The cartilaginous iliac crest apophysis is split, starting at the anterior superior iliac spine and continuing posteriorly for 6 to 8 cm.
With care, this cartilage splitting can be carried anteriorly down to the anteroinferior iliac spine (TECH FIG 1C).
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, Paso Robles, CA) can be placed in the sciatic notch to improve exposure (TECH FIG 1D), and a Gigli flexible wire saw is passed through the notch (TECH FIG 1E).
TECH FIG 1 • A. The first cut is the iliac cut. B. The incision is made just below the iliac crest as for a Salter osteotomy. C. The iliac crest apophysis is split to expose the medial and lateral aspects of the ilium down to the sciatic notch. D. Rang retractors are placed in the sciatic notch to facilitate passing the Gigli saw. E. A Gigli saw (arrow) is passed through the sciatic notch and is brought through the ilium to create the osteotomy.
The iliac osteotomy is then performed by bringing the Gigli saw anteriorly through the ilium, exiting at a point just above the anteroinferior iliac spine. 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.
PSOAS INTRAMUSCULAR LENGTHENING
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 posterior 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 identify the psoas tendon. A right-angled hemostat is 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 while the other osteotomies are completed.
PUBIC OSTEOTOMY
Earlier descriptions of TIO technique advised that the superior pubic ramus (TECH FIG 2A) be cut from the anterolateral Salter incision.
We initially used this but then changed to a separate medial incision, which makes exposure very easy and avoids risk to the neurovascular bundle (due to overretraction with the anterolateral approach; TECH FIG 2B).
For the three-incision technique, a 2- to 3-cm transverse incision (parallel to the inguinal ligament) is made just lateral to the adductor longus and 1 cm distal to the groin crease.
For the two-incision technique, this incision would subsequently be extended medially and distally to allow exposure of the ischium.
The pectineus muscle is identified just lateral to the adductor longus origin and is partially elevated off the superior pubic ramus. The saphenous vein, which often crosses the field, should be maintained and retracted laterally.
The ramus is identified and Hohmann retractors are placed above and below the pubis extraperiosteally (TECH FIG 2C).
The extraperiosteal approach allows easier periosteal sectioning since the periosteum is strong in this area and may prevent movement of the pubic segment of the acetabuloplasty.
Care must be taken to avoid the obturator nerve, which courses just below the superior ramus.
Those new to the operation might be advised to begin with a subperiosteal approach to the pubic ramus.
Fluoroscopy is used to confirm Hohmann retractor placement before making the osteotomy (TECH FIG 2D). The closer the surgeon is to the acetabulum, the easier it will be to rotate the acetabulum.
Once position is confirmed, a narrow rongeur or osteotome can be used to make a slightly oblique osteotomy of the pubis. 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.
TECH FIG 2 • A. The second cut is through the superior pubic ramus. B. The incision for the pubic cut is made distal to the groin crease. S.P.R., superior pubic ramus; I.T., ischial tuberosity. 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.
ISCHIAL OSTEOTOMY
The three-dimensional nature of the ascending ischium, buried deeply in muscle, is not easy to comprehend. When first performing this procedure, the surgeon should have a skeletal model of the pelvis in the operating room and the circulating nurse should hold it for him or her to inspect as needed. The proximity of the ischial spine to the sciatic nerve must be appreciated.
One error that we have seen is palpation of a deep bony prominence, thought to be the ischial spine, which was in fact the greater trochanter. The hip should be kept rotated internally to avoid this error.
Two-Incision Technique
Through the adductor incision, blunt dissection is carried out subcutaneously down to the ischial spine.
The electrocautery is used to take down the posterior portion of the adductor magnus muscle origin just anterior to the proximal origin of the hamstrings.
The ischial tuberosity is identified and then an initial sharp Hohmann retractor is placed inside the obturator foramen.
A Cobb elevator is then 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; TECH FIG 3A,B).
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 3C).
Thus, there are 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”).
TECH FIG 3 • A. The third cut is the ischial cut. 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.
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 encourage proper 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 3D).
Using a very long (about 20 inch) wooden-handled osteotome makes this essential rotational maneuver easier.
Three-Incision Technique
The hip is flexed to 90 degrees and a third incision is made longitudinally in the buttock just distal to the gluteal crease and medial to the ischial tuberosity (TECH FIG 4).
Otherwise the technique is identical to that noted above.
TECH FIG 4 • If a third incision is to be used, it is made just proximal to the gluteal crease, medial to the ischial spine.
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 (TECH FIG 5B,C). This is pushed upward and inward while the Schanz screw is levered downward and laterally to rotate the entire acetabulum around the femoral head.
A Cobb elevator is placed in the Salter (iliac) cut and rotated to encourage lateral positioning of the acetabular fragment in the coronal plane. Care must be taken not to externally rotate the acetabular segment (this is easy to do in a triple osteotomy and will cause undesired acetabular retroversion).
To avoid undesirable external rotation, Salter's advice that “even after the osteotomy the anterior superior and anterior inferior iliac spines should remain aligned” should be adhered to as well when a triple osteotomy is performed.
Through the Salter incision, a wedge of bone is removed from the iliac crest using an oscillating saw (TECH FIG 5D). The base of the wedge should be fashioned to fit tightly in the gap of the iliac osteotomy (TECH FIG 5E).
This triangular graft is only about half as large as in a Salter osteotomy for the same-size patient since a good deal of the rotation should have occurred in the pubic and ischial cuts.
The osteotomy is first fixed with temporary, sturdy smooth Kirschner wires (TECH FIG 5F).
Acetabular position is checked with fluoroscopy to confirm the amount of coverage that has been obtained.
TECH FIG 5 • A. 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 while the Schanz screw levers the superior acetabulum anterolaterally. C. Fluoroscopic image showing ballpoint pusher (white arrow) and Schanz screw (black arrow). D,E. Bone graft is taken from the iliac crest and fashioned to fit into the iliac osteotomy. F. The osteotomy is temporarily fixed using smooth Kirschner wires to confirm position with fluoroscopy before final screw fixation.
FIXATION OF THE OSTEOTOMIES
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 that 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.
We use two or three screws to adequately fix the acetabular fragment.
Threaded Kirschner wires can be used in smaller patients in whom the bone may not be thick (strong) enough to hold the 4.5-mm screw.
We prefer screws because later removal is easier.
In older, larger patients, we often place a 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 6A).
A second method for pubic ramus fixation includes a screw on either side of the pubic cut pulled together with a 20-gauge wire (TECH FIG 6B).
Any remaining bone graft fragments can be packed into the pubic and ischial osteotomies to prevent nonunion.
TECH FIG 6 • A. The pubic osteotomy can be fixed with a single screw. B. The pubic osteotomy can also be fixed with two screws and a tension wire.
WOUND CLOSURE
All of the incisions are thoroughly irrigated.
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.
Sterile dressings are applied. In most cases, a single hip spica is applied.
If both iliac and pubic fixation is secure in a cooperative patient, we sometimes use a removable bivalve plastic “spica-type” orthosis (made before surgery) or trust the patient with no immobilization (rare).
POSTOPERATIVE CARE
We recommend a single-leg spica cast for 6 weeks followed by partial weight bearing with crutches for an additional 4 weeks. If adequate bone healing is noted on radiography, 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 (if you elect to remove them). Whether the screw presence will hinder or compromise a later total hip replacement remains unclear. Clearly, femoral implants should be removed, but some consider acetabular screw removal less important. We lean toward removal of all implants from the hip in these patients, as they may require a later total hip replacement.
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 mediumterm results.
Guille et al8 reported more than 10 years of follow-up on 11 patients aged 11 to 16 with symptomatic hip dysplasia treated with TIO. Ten hips improved radiographically, eight improved functionally, and one required total hip arthroplasty.
Faciszewski et al3 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.
Peters et al20 evaluated 60 hips in 50 patients undergoing TIO. At an 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 pre-existing hip arthrosis.
When evaluating any procedure, it is important to evaluate the quality of each individual procedure, which is difficult to do in the literature. We have found through our own experience that the quality of the surgical procedure and the anticipated outcomes improve dramatically with surgeon experience.
When done properly and for the correct indication, TIO can improve the radiographs and symptoms of patients with hip deformity, whether the deformity is acetabular, femoral, or a combination of both.
The procedure is not without risks, and occasional patients have a poor outcome.
In patients with acetabular dysplasia, indications and outcomes are better understood.
The application of TIO for patients with femoral deformity (Perthes, AVN, epiphyseal dysplasia) has a shorter track record, but the procedure appears to provide clear benefit in properly selected cases.14,15
COMPLICATIONS
Inadequate coverage or containment
Creation of impingement either anteriorly or laterally
Sciatic or peroneal division nerve injury
Injury to the bladder, spermatic cord, obturator nerve, sciatic nerve
Loss of fixation or acetabular rotation
Infection
Nonunion of pubis or ischium
Hip stiffness
Progression to OA
Need for further surgery (deimpingement procedure, valgus rescue osteotomy of femur, Chiari osteotomy, shelf acetabuloplasty, hip fusion, total hip arthroplasty)
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· de Kleuver M, Kooijman MA, Kauer JM, et al. Pelvic osteotomies: anatomic pitfalls at the pubic bone: a cadaver study. Arch Orthop Trauma Surg 1998;117:270–272.
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· Hsin J, Saluja R, Eilert RE, et al. Evaluation of the biomechanics of the hip following a triple osteotomy of the innominate bone. J Bone Joint Surg Am 1996;78:855–862.
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