Triangle tilt and steel osteotomy: similar approaches to common problems

Each year, thousands of children worldwide suffer obstetric brachial plexus nerve injuries resulting not only in primary nerve injury, but also in development of secondary muscle and bone deformities of the shoulder. The triangle tilt surgery has been developed and shown to effectively address these deformities. The triangle tilt procedure was initially designed by the lead author (RKN) to follow the concepts of joint normalization featured in the Steel pelvic osteotomy used to correct developmental dysplasia of the hip joint, and indeed ultimately bears a striking resemblance to the Steel osteotomy. Prior to performing these bony surgical procedures, soft tissue procedures are performed to release the muscle contractures of the shoulder and hip. The purpose of this article is to compare and analyze the similarities between the indications, surgical techniques, involved anatomy, and outcomes of these operative procedures.

A literature review was conducted using PubMed to identify articles pertaining to triangle tilt surgery and the Steel pelvic osteotomy. Functional parameters and surgical strategies were compared. Pre- and post-operative CTs were analyzed to compare anatomical results of the procedures.

Similarities were found between both procedures in terms of indications, involved anatomy, surgical techniques, and outcomes. The triangle tilt surgery is indicated to correct the developmental dysplasia of the glenohumeral joint in obstetric brachial plexus injury patients. Steel pelvic osteotomy is performed to correct the subluxation and dislocation of the hip innominate bone in patients with congenital dysplasia, cerebral palsy myelodysplasia, and poliomyelitis. The involved anatomy of both procedures is similar in that both involve limb girdles and ball-and-socket joints, namely the shoulder and hip. Both procedures are also triple osteotomies, the triangle tilt involving the acromion, clavicle and scapula while the Steel osteotomy involves the iliac spine, ischial and pubic ramus of the innominate bone. Surgical techniques also bear likenesses in that both can theoretically be done percutaneously. Post-operative CT outcomes of both surgeries showed improved anatomical positioning of the ball-and-socket joint congruency, and therefore better functional outcomes.

The similarities between the triangle tilt surgery and Steel pelvic osteotomy could potentially be useful as a model system in developing other procedures that involve the shoulder and hip. Future clinical applications include the development and implementation of new surgical procedures based on comparisons and adaptations from the hip to the shoulder and vice versa.