We have performed open reduction with Pemberton osteotomy, as our primary treatment method for developmental dysplasia of the hip, in more than 550 patients at our institution since 1993. Originally described by Pemberton in 1965, the pericapsular pelvic osteotomy has been widely adopted for the treatment of acetabular dysplasia, hip subluxation, or frank hip dislocation in children1. Pemberton acetabuloplasty is characterized by a redirection of the acetabular roof, hinged on the triradiate cartilage after an incomplete iliac osteotomy. The shape of the acetabulum is modified by rotating the acetabular fragment caudally and anteriorly to improve the anterior and lateral coverage of the femoral head. Two similar modifications of the Pemberton osteotomy, the Dega osteotomy2 and the San Diego osteotomy3, were designed for the same purpose. With the Dega acetabuloplasty, the osteotomy penetrates the anterior and middle portions of the inner cortex of the ilium and leaves an intact posteromedial iliac cortex and sciatic notch as a posterior hinge. The San Diego acetabuloplasty utilizes complete bicortical osteotomies both anteriorly and posteriorly, to provide increased superior and posterior coverage. Most experienced pediatric orthopaedic surgeons can expect the Pemberton acetabuloplasty to yield greater correction of acetabular dysplasia than the Salter innominate osteotomy, without the need for internal fixation of the osteotomy site. Although some authors have cautioned against the use of the Pemberton osteotomy in children older than seven years because of concern about decreased remodeling potential and a less flexible triradiate cartilage4,5, some investigators have reported that the Pemberton osteotomy can be done at a later age with good results, when combined with a proximal femoral osteotomy6,7. Nevertheless, the iatrogenic injury to the triradiate cartilage resulting from an incorrectly performed Pemberton osteotomy is a possible serious complication, which may cause premature closure of the triradiate cartilage with a resultant shallow acetabulum8,9. In our previous study, children with developmental dysplasia of the hip who had excessive reduction of the femoral head following osteotomy had a higher risk of developing femoral head osteonecrosis10. The Pemberton pericapsular osteotomy has been recognized as an effective option for treating developmental dysplasia of the hip and has been the standard technique used over the last twenty years in our institution. The standard step-by-step surgical procedure used by us is outlined in this essential surgical technique.
In our previous study10, the pericapsular iliac osteotomy was performed as originally described by Pemberton1. We used an anterior iliofemoral surgical approach to expose the hip, and we routinely performed an iliopsoas tenotomy over the pelvic rim. Intra-articular obstructions were removed, and the transverse acetabular ligament was divided. A curved cut was then made on the inner and the outer wall of the ilium and extended to the posterior wing of the triradiate cartilage. The acetabulum could then be hinged and rotated anterolaterally. A triangular bone graft taken from the iliac crest was then placed in the osteotomy site to stabilize and maintain this corrected acetabular position. Postoperatively, all patients were placed in a hip spica cast, which they wore for six weeks.
The original study was approved by the institutional review board at our institution.
With the patient supine, make an anterior iliofemoral incision that is not directly on the iliac crest, dissect the subcutaneous tissue in the line of the incision, expose the iliac crest, and divide the cartilage at the iliac crest.
- Place the patient in a supine position with a towel roll under the buttock and the chest on the side on which the operation is to be performed.
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Make an anterior iliofemoral incision that is not directly on the iliac crest (Fig. 1).
- Dissect the subcutaneous tissue in the line of the incision. Identify the muscle interval between the sartorius and tensor fascia femoris muscles. Find the fatty tissue around the lateral femoral cutaneous nerve, which passes distally and laterally beneath the deep fascia in this intermuscular interval. Incise the fascia carefully and identify the nerve until it is clearly seen; then protect it with gentle traction. Retract the lateral femoral cutaneous nerve medially after it is well mobilized proximally and distally.
- Expose the iliac crest. Releasing the external oblique muscle fibers on the iliac crest facilitates exposure of the cartilaginous iliac apophysis. Identify the anterior superior iliac spine.
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To divide the cartilage at the iliac crest, use your thumb and index finger to identify the position of the iliac crest and sharply incise the iliac apophysis exactly in the midline (Fig. 2). Strip off each half of the iliac apophysis with a periosteal elevator to expose the ilium subperiosteally both medially and laterally. Pack a gauze sponge on the inner and outer cortices to facilitate subperiosteal dissection and provide hemostasis.
- Expose the anterior inferior iliac spine by elevating the periosteum with the hip abductor muscles from the outer cortex of the ilium until the anterior inferior iliac spine is clearly identified.
An anterior iliofemoral incision is used, caudal to the anterior superior iliac spine (ink outline to the right of the incision line mark) and the iliac crest. This is the left hip of the patient.
The iliac crest cartilaginous apophysis is split sharply, with the thumb and the index finger used to gauge the thickness and direction of the iliac wing. ASIS = anterior superior iliac spine.
Identify the rectus femoris tendon, release the iliopsoas muscle, and identify the acetabulum-hip capsule junction.
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Identify the tendon of the straight head of the rectus femoris muscle at its origin on the anterior inferior iliac spine. Transect the rectus femoris tendon close to the anterior inferior iliac spine but leave a short stump for later tendon reattachment (Fig. 3). Protect and preserve the ascending branch of the anterior femoral circumflex artery, which may be visible in the surgical field at this time.
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Bluntly dissect the iliacus muscle belly medial to the ilium and identify the psoas tendon at the level of the anterior pelvic rim. Release the tendinous part of the iliopsoas muscle (Fig. 4). Be careful of the femoral neurovascular bundle, which is located immediately medial to the psoas muscle but on the anterior aspect. The femoral neurovascular bundle can be retracted and protected with a blunt retractor.
- Identify the acetabulum-hip capsule junction. If the femoral head is well reduced in the acetabulum, you can identify the edge of the acetabulum and the reflected head of the rectus femoris muscle clearly. Dissect the soft tissue overlying the capsule and then identify the margin of the joint capsule at the acetabular rim. Sometimes the capsule becomes redundant and adherent to the ilium as a result of a previous femoral head dislocation. In this situation, dissect the abductor muscle from the capsule and use a periosteal elevator to strip off any soft tissue from the anterior aspect of the ilium to reveal the junction of the hip capsule and cartilaginous labrum.
The tendon of the straight head of the rectus femoris muscle is isolated and is divided just caudal to the anterior inferior iliac spine (AIIS).
The iliopsoas tendon is identified at the pelvic rim, and the tendinous portion is divided, leaving the muscular portion intact.
Perform an open reduction, check hip stability, make medial and lateral cut lines, and complete the osteotomy.
- Perform an open reduction. If the femoral head is dislocated, perform a T-shaped capsulotomy near the acetabular rim, including the upper and lower margins of the hip capsule (Fig. 5). Make the stem of the T-shaped capsulotomy parallel to the femoral neck, slightly superiorly to avoid a small inferior capsular flap, which will make the capsulorrhaphy more difficult. Remove the ligamentum teres sharply, and remove all of the fibrofatty tissue (pulvinar tissue) from the true acetabulum. Identify and palpate the tension of the transverse acetabular ligament with your finger before releasing it with scissors. Recheck to ensure that there is no tension of the transverse acetabular ligament after release, as remaining transverse acetabular ligament can impede complete reduction of the femoral head.
- Check hip stability. Reduce the femoral head into the acetabulum under direct vision and test the hip stability in a neutral position as well as in abduction and internal rotation. If the hip is unstable in a neutral position but is stable in abduction and internal rotation, a Pemberton acetabuloplasty is indicated. If hip stability cannot be maintained even in abduction and internal rotation, an additional proximal femoral varus and/or rotational osteotomy should be considered.
- Make medial and lateral cut lines. Remove the gauze sponge on either side of the iliac bone. Check bleeding from perforating vessels from the iliac wing. Once hemostasis is achieved, you can proceed with the Pemberton osteotomy. Locate the sciatic notch first with a small periosteal elevator and protect the adjacent soft tissue, including the sciatic nerve, with a retractor. Begin with the medial iliac cut first. Outline the cut line with the electrocautery tip. Using a small straight osteotome, begin the medial cut line about 1 to 1.5 cm above the superior hip joint line and curve it inferiorly and posteriorly, aiming at the sciatic notch (Figs. 6-A, 6-B, and 6-C). The cut line extends halfway to the sciatic notch and ends at the ridge of the pelvic inlet of the ilium. The lateral cut line has the same starting point as the medial cut. With the medial cut line as a reference, use the same osteotome to make the lateral cut line along the joint capsule (Figs. 7-A, 7-B, and 7-C).
- Complete the osteotomy. Use wider curved osteotomes to complete the osteotomy, beginning anteriorly and following the medial and lateral cut lines. As this osteotomy advances, push the osteotome against the distal fragment to check the degree of downward displacement. If the osteotomy site opens more than 2 to 3 cm, the distal fragment is hinging on the triradiate cartilage and there is no further advancement of the osteotome. If the opening is insufficient, advance the osteotome and check the amount of osteotomy opening again (Fig. 8).
Capsular incision outline with the stem of the T parallel with the femoral neck.
Medial cut line: outline on a skeletal model.
Medial cut line: outline on a reconstructed three-dimensional computed tomography (CT) scan.
Medial cut line in the surgical field. ASIS = anterior superior iliac spine.
Lateral cut line: outline on a skeletal model.
Lateral cut line: outline on a reconstructed three-dimensional computed tomography (CT) scan.
Lateral cut line in the surgical field.
Iliac osteotomy with use of a large curved osteotome.
Harvest the graft, position the reduced hip joint, insert the bone graft, repair the capsule, and close the wound.
- Harvest a wedge-shaped iliac crest bone graft (about a 35° wedge) from the iliac wing.
- Reduce the femoral head and place a towel roll under the knee to help maintain the hip in an abducted and flexed position.
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Hold the inferior osteotomy fragment open anteriorly and inferiorly with a towel clip to cover the femoral head. Then insert the triangularly shaped bone graft into the osteotomy opening site. Usually, the osteotomy bone graft is stable and there is no need for internal fixation (Figs. 9-A, 9-B, and 9-C). If the bone graft is not stable, fixation with one or two Kirschner wires may be necessary.
- Repair the hip capsule by bringing the two flaps of the T-capsulotomy to the acetabular flap of the capsule. It is not necessary to resect the redundant capsule. Repair the tendon of the straight head of the rectus femoris muscle to the anterior inferior iliac spine. Suture the iliac apophysis over the remaining ilium and close the wound.
Surgical field in which a bone graft is maintaining the opening of the osteotomy site.
Postoperative reconstructed three-dimensional computed tomography (CT) scan from the anterior view showing the bone graft in place.
Postoperative reconstructed three-dimensional computed tomography (CT) scan from the posterior view showing the bone graft in place.
Apply a hip spica cast after skin closure. An assistant should hold both hips in about 20° of flexion, 30° of abduction, and neutral or slight internal rotation while the cast is applied. The spica cast is worn for four weeks after a simple Pemberton osteotomy.
If a combined open hip reduction procedure was done, the hip spica cast is used for six weeks; this is followed by use, for four weeks, of a hip abduction brace or a bilateral cylinder cast with a spreader bar to hold the hips in 60° of abduction (30° of abduction for each hip).
In our clinical and radiographic review of forty-nine patients followed for more than ten years after treatment of developmental dysplasia of the hip with a unilateral Pemberton osteotomy, there were no redislocations and no patient required additional surgery for residual hip dysplasia after the original Pemberton osteotomy. If there was overcorrection or inferior displacement of the reduced femoral head, there was a higher risk of femoral head osteonecrosis10. Radiographs of one patient who was treated at the age of twenty months and was followed for fourteen years after the surgery are shown (Figs. 10-A, 10-B, and 10-C).
Anteroposterior pelvic radiograph of a twenty-month-old girl with developmental dysplasia of the left hip.
Immediate postoperative anteroposterior radiograph showing the reduced hip after the Pemberton osteotomy.
When the patient was fifteen years old, the left hip had an excellent result. (Asymptomatic asymmetry of the iliac wings may be noted if an iliac osteotomy of any type is done in a young child.)
Indications
- Developmental dysplasia of the hip
- Acetabular dysplasia
- Legg-Calvé-Perthes disease with femoral head subluxation/ lateral protrusion
- Anterosuperior deficiency of the acetabulum secondary to neuromuscular disease
- Sequelae of an infected hip with femoral head subluxation
Contraindications
- Closed triradiate cartilage
- Deformed femoral head
- Small acetabular volume
- Active infection/osteomyelitis
Pitfalls & Challenges
- Bone graft dislodgment
- Overcorrection may cause femoral head impingement and osteonecrosis
- Premature triradiate cartilage closure
- Transiliac lengthening of the ipsilateral limb at the time of the opening wedge osteotomy
- No c-arm fluoroscope is required in our technique. Is one necessary?
- We check the opening end point of the iliac osteotomy sequentially by testing the distal fragment for its flexibility as the osteotomy proceeds. This is different from the technique of proceeding straight to the end point at the triradiate cartilage.
- Transiliac lengthening of the ipsilateral limb is possible. How does the incidence of this complication compare with that following the Salter innominate osteotomy?
- Does acetabular volume decrease in Pemberton osteotomy? If so, by how much?
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