You are in: eMedicine Specialties > Orthopedic Surgery > PEDIATRICS Congenital Pseudoarthrosis of the ClavicleArticle Last Updated: Jun 11, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: L Andrew Koman, MD, Professor, Chair, Department of Orthopedic Surgery, Wake Forest University School of Medicine L Andrew Koman is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine, American Academy of Orthopaedic Surgeons, American Academy of Orthopaedic Surgeons, American Orthopaedic Association, American Orthopaedic Foot and Ankle Society, American Society for Reconstructive Microsurgery, American Society for Surgery of the Hand, Clinical Orthopaedic Society, Eastern Orthopaedic Association, North Carolina Medical Society, North Carolina Medical Society, Orthopaedic Research Society, Pediatric Orthopaedic Society of North America, Sigma Xi, Southern Medical Association, and Southern Orthopaedic Association Editors: Mininder S Kocher, MD, MPH, Associate Professor of Orthopedic Surgery, Harvard Medical School/Harvard School of Public Health; Associate Director, Division of Sports Medicine, Department of Orthopedic Surgery, Children's Hospital Boston; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; George H Thompson, MD, Director, Pediatric Orthopedics, Rainbow Babies and Children's Hospital; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Dennis P Grogan, MD, Clinical Professor, Department of Orthopedic Surgery, University of South Florida College of Medicine; Chief of Staff, Department of Orthopedic Surgery, Shriners Hospital for Children of Tampa Author and Editor Disclosure Synonyms and related keywords: congenital failure of formation clavicle, shoulder deformity, chest deformity, dextrocardia, situs inversus, neurofibromatosis, pseudarthrosis INTRODUCTIONSection 2 of 11
  Congenital failure of formation of the clavicle is a rare disorder. A painless mass over the right clavicle is the most common finding that prompts parents to seek consultation with a physician. Treatment may consist of mere observation or resection of the pseudoarthrosis and osteosynthesis.1, 2, 3, 4, 5, 6, 7 History of the ProcedureIn 1930, Saint-Pierre reported congenital failure of clavicle formation. In 1963, Alldred reported 9 cases of congenital pseudoarthrosis of the clavicle.8 Surgical intervention generally is recommended, to correct shoulder girdle hypermobility and an unsightly mass. Both problems can be treated by open reduction, resection of the pseudoarthrosis, and bone grafting.4 Resection alone produces pain. ProblemCongenital failure of formation (ossification) of the central portion of the clavicle produces a painless prominence in the anterior superior chest in the absence of trauma. The resultant synovial pseudoarthrosis is usually right-sided. Functional impairment is uncommon in children. FrequencyCongenital pseudoarthrosis is rare. Fewer than 200 cases have been reported in the English literature. The exact incidence and prevalence are unknown. The abnormality occurs almost entirely on the right side. Involvement of the left side usually occurs with dextrocardia and situs inversus.9 Bilateral cases can occur but are rare and are typically associated with genetic syndromes.10 EtiologyThe etiology is unknown, and no relationship with neurofibromatosis has been demonstrated. Abnormalities in aortic arch angiogenesis have been postulated, which would explain, in part, the right-sided distribution. Failure of coalescence of the two primary ossification centers contributes to the pathology.11 Left-sided involvement is seen in patients with dextrocardia and situs inversus. The incidence of associated cervical ribs is 15%. Spontaneous healing is extremely rare. PathophysiologyCongenital pseudoarthrosis of the mid portion of the clavicle occurs when an environmental insult or anatomic or mechanical event disrupts diaphyseal membranous ossification. In congenital pseudoarthrosis of the clavicle, the 2 primary ossification centers fail to unite. The 2 portions of the clavicle produced are connected by a fibrous bridge that is contiguous with the periosteum, and a synovial membrane develops.2 The predominance of right-sided involvement in the absence of situs inversus suggests that the vascular anlage of the subclavian artery that crosses the first rib just below the pseudoarthrosis site may be involved in the etiology. Congenital pseudoarthrosis has never been associated with malignant degeneration. ClinicalA painless mass or swelling over the clavicle is the usual presenting concern. The patient has no history of trauma, and shoulder and arm movement are normal. A family history of similar deformities is rare. Neurofibromatosis rarely is an associated diagnosis. In older children, pain is infrequent but may occur. In the typical presentation, the larger sternal side is tilted anteriorly and superiorly, and the smaller acromial portion curves gently to meet the pseudoarthrosis. The mass usually is painless, range of motion is full, and function is normal. Café au lait lesions usually are not seen. INDICATIONSSection 3 of 11
Indications for intervention include pain, shoulder girdle instability, and altered self-esteem secondary to an unsightly appearance. RELEVANT ANATOMYSection 4 of 11
The clavicle is the first bone to undergo membranous ossification. It connects the sternum to the acromion and provides support for shoulder function. CONTRAINDICATIONSSection 5 of 11
No major contraindications to intervention exist. However, internal fixation may be compromised due to the size of the patient (and the clavicle). WORKUPSection 6 of 11
Lab Studies
Imaging Studies
Histologic FindingsHistologic findings consist of synovial-lined pseudoarthrosis.11 TREATMENTSection 7 of 11
Medical therapyMere observation may be appropriate. No nonoperative techniques achieve union. Surgical therapySurgical intervention is indicated for pain, appearance that negatively impacts self-esteem, and shoulder deformity interfering with function.13 Preoperative detailsAfter taking a general history and performing a physical examination, evaluate the right upper extremity for range of motion, stability, and neurovascular function. The patient should be prepared for surgery, and the entire right upper limb prepared free to facilitate mobilization of the clavicle and to observe for neurovascular problems. Prophylactic antibiotics are appropriate if internal fixation is employed. A semisitting or beachchair position may be helpful to obtain exposure. Intraoperative detailsSurgical steps are as follows:
Postoperative detailsPostoperatively, the patient is immobilized in a sling and swath; alternatively, a shoulder spica may be used for small children if internal fixation is inadequate.15 The clavicle is protected until union is confirmed clinically and radiographically. COMPLICATIONSSection 8 of 11
The major surgical complication is failure of the clavicle to unite. However, in contradistinction to congenital pseudoarthrosis secondary to neurofibromatosis, union is common. Hardware is removed if painful or unduly prominent. Neurovascular injury is rare but may occur. Infection may occur in the postoperative period. OUTCOME AND PROGNOSISSection 9 of 11
The outcome is usually excellent, with prompt healing, few complications, and normal function. FUTURE AND CONTROVERSIESSection 10 of 11
In the future, the true etiology of congenital pseudoarthrosis may be delineated, and its predilection for the right chest will be understood. It is likely that injection with osteoinductive material will convert the pseudoarthrosis to normal membranous ossification or that the application of external bone-stimulating devices will induce osteoprogenitor cells to replace the pseudoarthrosis with normal bone. REFERENCESSection 11 of 11
Congenital Pseudoarthrosis of the Clavicle excerpt Article Last Updated: Jun 11, 2008 |
