This single innominate osteotomy is useful to correct mild to moderate acetabular dysplasia from ages 18 months into adult life. Salter osteotomy is widely used, and good to excellent outcomes are usually reported. Modifications include infrapelvic lengthening and performing the osteotomy with an osteotome, preserving the medial cortical periosteal attachments, enhancing stability, and eliminating the need for internal fixation.
Technique of Salter Osteotomy
Exposure Expose the hip through a bikini incision and an iliofemoral approach splitting the iliac apophysis. Perform an open reduction as necessary. By subperiosteal dissection, expose the inner and outer surfaces of the ilium to expose the sciatic notch. Place retractors in the notch to protect the sciatic nerve.
Psoas tenotomy In most patients, an intramuscular lengthening of the psoas is performed before the osteotomy. Identify the tendon within the muscle and divide only the tendon, leaving the muscle intact.
Osteotomy Perform the innominate osteotomy with a Gigli saw. Passing the wire saw around the notch is the most difficult step in the procedure. This may be accomplished by using the special saw passer, by placing a curved clamp around the notch, or by simply bending the saw blade and guiding it around with a curved clamp. Once the saw is passed, position the retractors to protect the soft tissues, and perform the osteotomy. Make certain the osteotomy exits at the anterior inferior iliac spine.
Graft Place a towel clip in the anterior iliac spine to secure the graft. Remove a triangular graft that includes the anterior iliac spine using a bone cutter or osteotome. Reshape the graft into the desired triangular shape with the base about 2–3 cm in width.
Placing the graft Place a second towel clip through the ilium just above the acetabulum. Place the leg in a figure 4 position, and with pressure on the flexed knee and traction on the towel clip, open and slightly laterally displace the acetabular segment. This should open the osteotomy laterally while keeping the medial cortical margins approximated. Place the graft in the open defect.
Fixation Secure the fixation with two or three pins that penetrate the graft and both iliac surfaces. These pins may be smooth or threaded. Make certain the pins do not penetrate the hip joint and are long enough for firm purchase on the lower fragment. Cut off the pins, allowing about 5–10 mm protruding above the cortical margin. It is important to cut the pins at a length that is long enough to facilitate removal but not so long as to cause skin irritation.
Closure is standard with a subcuticular skin closure. Immobilize in a spica cast for 6 weeks.