The treatment for residual hip dysplasia without clinical instability for infants <6 months of age consists of application of a Pavlik harness or abduction bracing [17]. The harness is worn initially 16–18 h per day and then weaned to a nighttime brace within the first month of treatment. The night time bracing continues until the radiographic AI measurement is <30° and the sourcil is normal in appearance. After the hip has normalized based on such radiographic parameters, the bracing is discontinued and the patient is followed annually until the age of 5 years.

The treatment for residual hip dysplasia for patients >6 months to 2 years of age consists of hip abduction bracing (Box 29.3). These older infants and toddlers are often too large and strong for the Pavlik harness, but a nighttime abduction brace is very effective. The main difficulty with this treatment in the older toddler is the compliance with the orthosis. However, in the authors’ experience, once the potential surgical option is discussed with the parents, the compliance with the bracing often improves. Despite limited published data, this simple orthotic treatment is common among pediatric orthopedists and can yield a high success rate with resolution of the hip dysplasia in the vast majority of patients if the brace is worn consistently. A recent study has shown that part-time abduction bracing significantly improves residual acetabular dysplasia at 6 months of age versus observation alone [18]. After the hip has normalized radiographically, the abduction brace is discontinued and the patient is followed annually at least until the age of 5 years.

Once the child is older than 2 years of age, the nighttime bracing becomes very difficult due to patient cooperation and compliance. However, in the older toddler, if the nighttime hip abduction brace could be tolerated, then this would be the initial treatment strategy as stated above for the younger child. For the majority of older toddlers and young children, the treatment for clinically significant hip dysplasia consists of a single cut pelvic osteotomy that hinges on the triradiate growth plate or the pubic symphysis (Box 29.4). The direction and severity of acetabular deficiency influences the exact type of pelvic osteotomy that is performed. The type and direction of coverage of the commonly used pelvic osteotomy is as follows: the Pemberton pelvic osteotomy primarily provides anterior coverage, the Dega pelvic osteotomy covers anterolaterally, and the San Diegoplasty covers laterally [10]. These three “volume-reducing” osteotomies are very similar but with distinct differences. All three are incomplete osteotomies, hinging on the triradiate cartilage and do not usually require internal fixation for stability.

The Dega osteotomy is the classic pelvic osteotomy that hinges on the triradiate growth cartilage [19, 20]. The Dega osteotomy begins at the anterior inferior iliac spine and curves posteriorly around the acetabulum to end at the triradiate cartilage. Medially, the Dega pelvic osteotomy is directed in a curvilinear fashion over the acetabulum towards the triradiate cartilage, leaving the inner table intact. Wedges of bone graft (autograft harvested from the iliac crest or the proximal femur when a shortening is being performed, versus allograft bone), can strategically be placed in the osteotomy site to provide a combination of increased anterior and/or lateral coverage (Fig. 29.5a, b).

Two modifications of the Dega-type osteotomy are the San Diegoplasty osteotomy and the Pemberton osteotomy (Fig. 29.6a–e). The San Diegoplasty osteotomy does not violate the inner table; however, a notch of bone is removed with a Kerrison rongeur at the anterior inferior iliac spine and the sciatic notch. This allows more coverage directed laterally without sacrificing posterior coverage, and was originally described for hip dysplasia associated with neuromuscular disease, which typically entails posterior acetabular deficiency [21] (see Fig. 29.6a–c).

The Pemberton osteotomy, first described in 1965, also hinges on the triradiate growth cartilage, but the direction of this osteotomy is from an anterior to posterior direction instead of a lateral to medial direction, as with the Dega and San Diegoplasty [22]. The Pemberton osteotomy begins at the anterior inferior iliac spine and curves over the acetabulum and ends at the triradiate growth cartilage posterior to the joint identical to the Dega osteotomy. However, the Pemberton osteotomy divides both the inner and outer tables of the ilium as it heads over the acetabulum to the triradiate cartilage. This creates a pure anterior opening wedge osteotomy with a greater increase of anterior coverage for the acetabulum (see Fig. 29.6d, e).

Another type of pelvic osteotomy that can be used in this age group is the Salter osteotomy that consists of a complete osteotomy from just above the anterior inferior iliac spine to the sciatic notch, including both inner and outer tables of the ilium [23]. The Salter is a redirectional osteotomy that hinges on the flexible symphysis pubis and requires internal fixation due to the amount of inherent instability. However, the Salter osteotomy affords greater movement of the acetabulum and thereby a greater ability to correct a more severe dysplasia. The surgeon must be aware that a dysplastic acetabulum with poor posterior coverage is a relative contraindication for a Salter osteotomy, as while it provides excellent anterolateral coverage, it can further uncover the femoral head posteriorly (Fig. 29.7a–f).

Postoperative care for innominate pelvic osteotomies requires non-weight bearing for approximately 6 weeks. The patients between the ages of 2 and 5 years are placed into a 1-½ hip spica cast for the initial 6 weeks, whereas the older patients (6 years and older) are often placed into a hip abduction pillow. After the initial 6-week period, the cast/pillow is discontinued and physiotherapy is started. The patient gradually returns to full weight bearing. Full activity is allowed after reestablishing full hip strength and range of motion. The patient is then followed annually until skeletal maturity.

As the patient becomes older, the treatment for hip dysplasia becomes more complicated and invasive. However, unlike the asymptomatic younger child who is usually diagnosed incidentally and treated prophylactically, the older patient typically presents with mild to moderate pain associated with activity. Therefore, the treatment goals in this age group are the alleviation of pain, improved joint function, and prevention of early degenerative joint disease of the hip.

In the authors’ practice, the preferred method of treatment for symptomatic residual hip dysplasia in the young patient after the closure of the triradiate cartilage is the periacetabular triple osteotomy (Box 29.5). The triple is a redirectional osteotomy including ischial, pubis, and supra-acetabular innominate bone cuts. An early technique described by Steel has continued to evolve [24]. Tonnis modified the procedure by performing the ischial cut in closer proximity to the acetabulum, facilitating acetabular fragment mobility and greater correction of severe acetabular dysplasia [25]. Originally described as two-incision procedure, further modifications of the triple osteotomy utilize a one-incision technique [26]. Because this is a complex osteotomy, a brief description of the technique will follow, highlighting certain technical tips.

The Ganz periacetabular osteotomy is another very popular type of pelvic osteotomy [27]. This particular osteotomy maintains the integrity of the posterior column by performing a bone cut connecting the iliac osteotomy to the partial ischial osteotomy. This osteotomy travels through a very narrow column of bone in the young patient. Therefore, the author prefers the periacetabular triple technique for adolescent and smaller adult patients

The patient is placed supine on the operating table with no bumps placed under the pelvis. The entire lower extremity, to include the groin, gluteal region, and subcostal area are prepared and isolated into the sterile field. A single incision is performed in the flexion crease of the hip joint, approximately 1 cm below the anterior superior iliac spine. This incision starts just medial to the palpable neurovascular bundle and extends 6–8 cm lateral to the anterior superior iliac spine (Fig. 29.8).

The entire operation is performed through this single anterior incision. The interval between the sartorius and tensor fascia lata muscles is defined in the typical fashion protecting the lateral femoral cutaneous nerve. The rectus femoris tendon is identified and released, tagging the insertional portion of tendon. Next, the iliac crest is exposed. Both the inner and the outer tables are subperiosteally dissected to the sciatic notch. Surgical gauze and/or bone wax may be used to control bleeding from the iliac wing. Dissection of the medial structures is subsequently performed. The fascia overlying the sartorius and iliopsoas muscles is divided. The iliopsoas tendon is identified (typically on the posterior aspect of the muscle) and fractionally lengthened within the muscle belly. Gentle retraction of the iliopsoas muscle belly brings the femoral nerve into the operative field. The femoral nerve should be identified prior to the division of the iliopsoas tendon. The femoral nerve, artery, and vein are carefully identified and exposed with individual small vessel loops placed around each structure. Fluoroscopic visualization of the superior pubic ramus is performed to confirm the osteotomy position just medial to the pubic eminence (Fig. 29.9). It is always surprising how medial the dissection must be carried out in order to place the superior pubic ramus osteotomy in the correct position. Typically, the osteotomy site lies between the femoral nerve and artery. However, with smaller patients, the osteotomy position can be medial to the femoral vein. The interval between the femoral nerve and artery is exposed down to the periosteum of the superior pubic ramus. Great care must be used when retracting the neurovascular bundle. If the interval for the exposure of the superior pubic ramus is performed lateral to the femoral nerve, the tension placed on the neurovascular structures will be substantially increased in order to reach the proper osteotomy position.

After the exposure of the correct interval for the pubic ramus osteotomy is completed, the overlying periosteum is divided. Multiple drill holes are created in the superior pubic ramus using a smooth 1.8- to 2.0-mm wire. The osteotomy is completed with an osteotome. The interval for the ischial osteotomy is then created. This interval lies between the medial aspect of the hip capsule and the iliopsoas muscle. The interval is carefully created with gentle blunt dissection using a large curved Mayo scissor. The interval is opened and widened by gentle spreading of the blunt tipped scissor. A small Cobb elevator is placed into the interval to palpate the superior portion of the ischium, just below the acetabulum (Fig. 29.10). A Cobb elevator is advanced on both the medial and lateral sides of the ischium to push the soft tissues away and prepare a path for the Ganz osteotome (see Fig. 29.11d, e).

The Ganz osteotome is inserted into the prepared interval and positioned just under the acetabulum. It is critical to have adequate fluoroscopic visualization for this osteotomy. The osteotome is aimed approximately 45–55° proximally in order to direct the osteotomy above the ischial spine (Fig. 29.11a–e).

This osteotomy is visualized with an oblique fluoroscopic view, similar to an obturator Judet view (C-arm is rotated toward the operative hip between 30° and 50° from the AP position). Again, fluoroscopic visualization of the acetabulum, ischium, and ischial spine is essential in this oblique view in order to complete the periacetabular ischial osteotomy successfully. Another critical technical tip is the protection of the femoral nerve while completing the ischial osteotomy. During this osteotomy, the hip must be flexed 15–20° to prevent stretch of the femoral nerve as the Ganz osteotome handle is levered distally in order to aim the osteotomy above the ischial spine. Before the final osteotomy of the ilium, two reference half pins are inserted into the acetabular fragment. These two reference half pins enhance the accuracy of the bony correction and help prevent secondary deformities (Fig. 29.12).

The first half pin is place from the anterior to posterior direction, just lateral to the superior pubic ramus osteotomy. This anterior reference half pin marks the acetabular version. The second half pin is inserted from lateral to medial in the supra-acetabular region, parallel to the roof or sourcil of the acetabulum. This lateral reference half pin marks the dysplastic acetabular roof. After the reference half pins are placed, the final osteotomy of the ilium is performed. A Gigli saw is carefully passed through the sciatic notch. The final osteotomy is completed with the Gigli saw from the sciatic notch to the anterior aspect of the ilium, just above the anterior inferior iliac spine.

The acetabular fragment should become freely mobile after the third cone cut. If the fragment does not easily move, then the pubic ramus osteotomy and ischial osteotomy are revisited with repeat passage of the osteotome. After mobilizing the acetabular fragment, the reference half pins are used to reorient the acetabulum and temporary fixation is performed (Fig. 29.13a). The anterior half pin should still be pointed in a straight anterior to posterior direction if the version of the acetabulum was planned to remain the same. If anteversion is needed, then the anterior half pin should be internally rotated. Similarly, if the anterior half pin is externally rotated, retroversion has been imparted to the new acetabular position. The temporary fixation consists of three separate 1.8-mm Ilizarov or similar sized smooth k-wires. After adequate correction and repositioning of the acetabulum is completed and confirmed under fluoroscopy, the wires are sequentially overdrilled with a cannulated 3.2-mm drill bit and solid 4.5-mm screws are inserted for final stabilization (Fig. 29.13b).

The following figures are case examples of the triple pelvic osteotomy (Figs. 29.14, 29.15, and 29.16).

Closure proceeds with repair of the iliacus fascia to the gluteus medius fascia to cover the exposed iliac crest, repair of the rectus femoris tendon, and a layered closure of the subcutaneous tissues and skin over a drain.

The patient is placed into a hip abduction pillow prior to leaving the operative suite and converted to a single leg hip abduction brace before discharge from the hospital. Toe-touch weight bearing is allowed with crutches or a walker for 6 weeks. After radiographic confirmation of healing, the patient is advanced to full weight bearing and physiotherapy.

The modified Dunn procedure is performed with the patient in the lateral decubitus position. The incision is centered on the greater trochanter with approximately 5–8 cm distal and 5–8 cm proximal (Fig. 29.17).

The interval between the tensor fascia lata and gluteus maximus muscles is used to gain access to the level of the vastus lateralis and gluteus medius muscles. The posterior border of the vastus lateralis muscle is identified at the level of the vastus ridge. The posterior border of the gluteus medius muscle is identified along with the piriformis tendon and the sciatic nerve. A greater trochanteric osteotomy is performed with an oscillating saw that connects the posterior border of the vastus lateralis muscle to the posterior border of the gluteus medius muscle. The greater trochanteric fragment should be approximately 1–1.5 cm thick for adequate fixation at the end of the procedure. The digastric muscle flap to include the vastus lateralis muscle, the greater trochanteric fragment, and gluteus medius muscle is flipped medially allowing exposure of the gluteus minimus muscle and underlying hip joint capsule (Fig. 29.18a–c).

The next step in the procedure is the exposure of the hip capsule and the Z capsulotomy. A small Cobb elevator is used to lift the gluteus minimus muscle off of the capsule and provide an interval for a Taylor retractor to be inserted onto the outer table of the ilium. The surgeon will note a prominence in the hip capsule caused by the superior ridge of the femoral neck that was “left” behind as the femoral head progressively slipped in a posterior and medial direction. The Z-capsulotomy is performed with the longitudinal limb in the midline of the capsule. The anterior limb of the capsulotomy is performed at the base of the femoral neck while the posterior limb is extended along the posterior rim of the acetabulum (Fig. 29.19).

The critical step at this point in the procedure is the creation of the retinacular soft tissue flap that will contain the blood vessels to the femoral head. Careful removal of bone from the base of the greater trochanter will create this flap that consists of the proximal femoral periosteum, pericapsular retinaculum, and short external rotator muscles. The creation of this flap is accomplished by removing 5–8 mm of bone from the posterior aspect of the greater trochanteric base by the “inside out technique”(Fig. 29.20). It is critical to minimize soft tissue tension and stretch while excising the bone.

Similarly, the proximal aspect of the greater trochanter base is removed to create a surface that is flush with the superior portion of the femoral neck. This will result in the “relative” femoral neck lengthening after the greater trochanteric fragment is advanced distally during the closure.

If the femoral head has not been previously secured with prior screw fixation, then temporary fixation with a stout single threaded K-wire is performed (Fig. 29.21). The hip is gently dislocated with release of the ligamentum teres from the fovea capitis. After the femoral head is delivered out of the joint, the acetabulum and labrum are inspected for any detrimental changes. Next, the periosteum and retinaculum of the femoral neck is carefully peeled from anterior to the mid-line both medially and laterally. The lateral aspect of this dissection is critical and the continuity of the soft tissue flap to the femoral head must be maintained.

Following dislocation, the femoral head fixation is removed and a curved osteotome is inserted into the physis. Gentle levering of the curved osteotome is performed to allow the femoral head to gradually detach from the femoral neck. While the femoral head is carefully being levered off the neck, the retinacular soft tissue flap should be visualized to prevent any tearing or stretching. If the final posterior portion of the physis is difficult to detach, the osteotome is carefully directed slightly distally, removing a small portion of the posterolateral femoral neck with the femoral head in order to protect the blood supply. The femoral head along with the soft tissue vascular flap is allowed to fall back into the acetabulum and the femoral neck is lifted into the operative field for inspection (Fig. 29.22).

The femoral neck is trimmed of excess bone and shortened to eliminate any tension of the vascular leash with femoral head reduction. The shortening does not have to be excessive, approximately 1 cm, as long as no tension of the blood supply is evident when the femoral head is reduced. The femoral head is carefully retrieved from the acetabulum and reduced to the “new” femoral neck. The vascular retinacular leash is inspected to insure no tension is present after which temporary K-wire fixation is performed. The hip joint is reduced and its position is confirmed under fluoroscopy. The fixation is finalized via 4.5-mm screws, 3.5-mm screws, or threaded K-wires. The size of the fixation depends on the size of the femoral head and balancing stable fixation while minimizing the amount of area of the femoral head violated to prevent devascularization. The capsule is repaired with care not to over tighten the posterior capsule, which could stretch the blood supply to the femoral head. The greater trochanter is advanced distally and repaired with two 4.5 mm solid screws or two 5.5-mm cannulated screws. The goal of the greater trochanteric transfer is to advance the proximal tip of the greater trochanter below the newly established center of the femoral head (Fig. 29.23). The remainder of the closure is performed in the typical fashion over a drain.