Nontraumatic Disorders of the Clavicle Abstract Other than those resulting from trauma and arthritis, disorders of the clavicle are uncommon. Some nontraumatic disorders are found only in infancy and childhood, such as birth fracture, infantile cortical hyperostosis, congenital pseudarthrosis, cleidocranial dysplasia, and short clavicle syndrome. Other nontraumatic disorders occur in both children and adults; these include anterior subluxation of the sternoclavicular joint, Friedrich’s disease, hypertrophic osteitis, chronic multifocal periosteitis and arthropathy, and osteomyelitis. Some nontraumatic clavicular disorders are found only in adults, such as distal osteolysis. Because the description and nomenclature of these disorders arise from several medical disciplines, they often are confusing. Until clear, distinguishing features are described, it is advisable to combine some of the entities. This is especially true of the nonsuppurative inflammatory disorders of the clavicle, which appear to fall under the heading of spondyloarthropathy. Treatment varies by disorder and may include symptomatic and expectant management, drug therapy, and nonsurgical or surgical treatment. N ontraumatic disorders of the clavicle are uncommon, and frequently the diagnosis is not obvi- ous. Some conditions occur only in infancy or early childhood, some only in adulthood; some occur in both childhood and adulthood, but with varied manifestations. The no- menclature is confusing because several titles have been used to de- scribe the same disorder. For many nontraumatic clavicular conditions, the cause is uncertain, the patholo- gy is not specific, and the natural history is not completely known. Disorders of Infancy and Childhood Birth Fracture of the Clavicle The most common abnormality of the clavicle in infancy is fracture associated with delivery. It occurs in between 0.5% and 0.9% of vaginal births and has equivalent sex and side distribution. Risk factors in- clude large fetal size and shoulder dystocia. 1 Nine percent of infants with a clavicle fracture also will have a brachial plexus palsy. Birth fracture of the clavicle is suspected by the presence of known risk fac- tors, lack of use of the upper extrem- ity, or deformity or tenderness of the clavicle. The condition is confirmed by radiographs, which demonstrate a fracture in the middle third (Figure 1). An apparent fracture of the clavi- cle at birth does not always indicate birth trauma; syndromes involving chromosomes 11, 18, and 22 have been reported with congenital de- fects of the clavicle. Congenital pseudarthrosis of the clavicle also Rodney K. Beals, MD Donald D. Sauser, MD Dr. Beals is Professor, Department of Orthopaedics and Rehabilitation, Oregon Health Sciences University, Portland, OR. Dr. Sauser is Professor, Department of Diagnostic Radiology, Oregon Health Sciences University. None of the following authors or the departments with which they are affiliated has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Beals and Dr. Sauser. Reprint requests: Dr. Beals, Department of Orthopaedics and Rehabilitation, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, OP 31, Portland, OR 97239. J Am Acad Orthop Surg 2006;14:205- 214 Copyright 2006 by the American Academy of Orthopaedic Surgeons. Volume 14, Number 4, April 2006 205 may be present at birth. Clavicle fractures at birth are treated by splinting the arm to the thorax, a protection that may be discontinued in 10 to 14 days, when abundant cal- lus typically has developed. Birth fracture of the clavicle has no per- manent sequelae. Infantile Cortical Hyperostosis Present at birth or occurring in the first 6 months of life, infantile corti- cal hyperostosis (Caffey’s disease) is rare and characterized by painful periosteal elevation involving one or more bones. The clavicle and mandi- ble are the most commonly affected, but the ulna, tibia, femur, scapula, humerus, ribs, and other bones may be involved. 2 The cause of infant cor- tical hyperostosis is unknown but is reported to be familial and inherited. It often is associated with fever, ane- mia, elevated white blood cell (WBC) count, elevated alkaline phosphatase level, and elevated erythrocyte sedi- mentation rate (ESR). Radiographs of the involved bone demonstrate peri- osteal new bone formation (Figure 2). Patients suspected of having infantile cortical hyperostosis should undergo a skeletal survey that includes the skull and extremities. The differential diagnosis in- cludes conditions that cause peri- osteal elevation, such as infection, trauma, neoplasia, hypervitaminosis A and D, and syphilis. The diagnosis is made on the basis of clinical and radiographic findings; usually biopsy is not needed. Treated by symptomatic manage- ment, infantile cortical hyperostosis has a natural history of spontaneous resolution of pain and swelling. The radiographic abnormalities disap- pear over 1 to 2 years, rarely leaving residual abnormalities. Congenital Pseudarthrosis of the Clavicle Congenital pseudarthrosis of the clavicle is a rare condition, some- times associated with cervical or ab- normal ribs. It typically occurs on the right side (95%), sometimes bilater- ally (10%), and more commonly in females. 3 Although the cause of con- genital pseudarthrosis is not known, it is not the result of acute trauma. One hypothesis suggests that pseud- arthrosis is a result of pressure on the fetal clavicle from the underlying subclavian artery. 3 This hypothesis is supported by reports of the condition occurring on the left side in patients with dextrocardia. Although a number of familial oc- currences have been described, there is no mendelian pattern of inheri- tance. It is present at birth but usu- ally is diagnosed in childhood be- cause of anterior prominence of the mid clavicle or asymmetry of the shoulder girdle with a mobile mid clavicle. Congenital pseudarthrosis of the clavicle is asymptomatic in early childhood but usually becomes symptomatic as the child under- takes the more strenuous activities of throwing and lifting. Radiographs show sclerotic smooth bone margins that are characteristic of pseudar- throsis (Figure 3). The differential diagnosis in- cludes posttraumatic pseudarthro- sis, cleidocranial dysplasia, and neurofibromatosis. Posttraumatic pseudarthrosis of the clavicle is very rare in childhood but has been re- ported. Bilateral congenital pseudar- throsis of the clavicle has been not- ed in association with trisomy 22. Either surgical or nonsurgical treatment is acceptable manage- ment. The usual indications for sur- gery are a combination of cosmetic and symptomatic concerns that de- velop in mid childhood. The most common surgical treatment in- volves open reduction, removal of prominent bone, iliac bone graft, and fixation by a contoured plate. 4 Bra- chial plexus neuropraxia has been re- ported following resection and fixa- tion of the pseudarthrosis. 5 Figure 1 Anteroposterior radiograph demonstrating birth fracture of the right mid clavicle in a newborn. Figure 2 Anteroposterior radiograph demonstrating periosteal new bone on the right clavicle in a patient with infantile cortical hyperostosis. The scapula is also involved. Figure 3 Anteroposterior radiograph of deformity of the right mid clavicle associated with congenital pseudarthrosis. The bone margins adjacent to the pseudarthrosis are smooth and deformed. Nontraumatic Disorders of the Clavicle 206 Journal of the American Academy of Orthopaedic Surgeons Cleidocranial Dysplasia Cleidocranial dysplasia (absent clavicle) is a generalized bone dys- plasia that usually includes bilateral congenital absence of the mid clavi- cle. The absence may range from hy- poplasia to total absence and is usu- ally asymptomatic. Absence of the mid clavicle allows increased for- ward movement of the shoulders. The diagnosis generally is clinically apparent because of increased shoul- der mobility and abnormal facies (Figure 4). The characteristic facies include a broad and prominent fore- head, delayed ossification of the fon- tanelle, depression at the base of the nose, and supernumerary teeth. Mild short stature, peripheral joint laxity, mild kyphosis, and scoliosis are common associated findings. Cleidocranial dysplasia is transmit- ted by autosomal dominant inheri- tance; the gene is on chromosome 21. Radiographs of the skull demon- strate delayed closure of the fonta- nelles, wormian bones, and a mild increase in the size of the calvaria. Other radiographic features include platybasia, hypoplasia of the sphe- noid, hypoplasia of the maxilla, and delayed union of the mandibular symphysis. There are supernumer- ary teeth. Spondylolysis and spina bifida occulta have been noted in the spine. There is delayed ossification and underdevelopment of the pubic bones, with widening of the pubic symphysis. The proximal femurs may exhibit developmental and pro- gressive coxa vara. 6 The differential diagnosis includes a syndrome of cleidocranial dysplasia associated with severe mental retar- dation and absence of the thumbs, unilateral complete absence of the clavicle, and a rare autosomal reces- sive form of cleidocranial dysplasia. Congenital absence of the clavicle is treated symptomatically. Short Clavicle Syndrome Short clavicle syndrome is bilat- eral symmetric shortening of the clavicle that allows the scapula to rotate forward, causing prominence of the shoulders anteriorly and spreading and prominence of the scapula posteriorly (Figure 5). It is transmitted by autosomal dominant inheritance but is often sporadic. This condition is asymptomatic in childhood and usually presents as a postural concern. 7 Radiographs are not diagnostic. The clavicle tends to be horizontal, and the scapulas appear wide-spaced on a chest radiograph. There is no in- crease in thoracic kyphosis. The differential diagnosis includes scapular winging from nerve palsy and muscle weakness or congenital muscle absence. Salter and Kay 8 de- scribed one family with a dominant short clavicle with forward fixation of the scapula associated with a fi- brous band extending from the first rib to the coracoid process. Congenital short clavicle normal- ly requires no treatment. A single se- vere case has been treated by a lengthening osteotomy. 9 Dysplasias and Syndromes That Include Clavicle Abnormality Increased sclerosis, widening, or cortical irregularity of the clavicle in childhood, when associated with dysmorphism, abnormal facies, or delayed development, suggest the possibility of a syndrome or skeletal dysplasia. Children with unusual ra- diographs of the clavicle should un- dergo a skeletal survey to search for other abnormalities. Disorders of Childhood and Adulthood Anterior Subluxation of the Sternoclavicular Joint Spontaneous anterior subluxation of the sternoclavicular joint during overhead activities without a history of trauma is an uncommon condi- Figure 4 A patient with cleidocranial dysplasia. She is able to bring her shoulders together anteriorly because of the absence of segments of her right and left clavicles. Figure 5 A patient with short clavicle syndrome, resulting in forward rotation of the scapula with anterior prominence of the shoulders and posterior prominence of the scapula. Rodney K. Beals, MD, and Donald D. Sauser, MD Volume 14, Number 4, April 2006 207 tion. This condition, sometimes as- sociated with throwing or gymnas- tics, typically appears between age 10 and 35 years and occurs equally in males and females. It also has been described in middle-aged women. 10 It is usually unilateral, occurring on the dominant side, but is bilateral in ap- proximately 10% of patients. Laxity of the costoclavicular ligaments must exist for subluxation to occur, and affected patients typically dem- onstrate generalized joint laxity. The diagnosis usually is made on clinical examination. Radiographic asymmetry in the size of the medial clavicle suggests subluxation of one clavicle. A radiograph with 40º ceph- alad tube angulation (serendipity view) visualizes the sternoclavicular relationship and may be helpful. Computed tomography (CT) will best demonstrate the relationship of the clavicle to the manubrium (Fig- ure 6). The differential diagnosis in- cludes rheumatoid arthritis, infec- tion, and other disorders associated with prominence of the medial clav- icle and the sternoclavicular joint. Anterior subluxation of the ster- noclavicular joint is mildly symp- tomatic and does not preclude active sports. Therefore, treatment is usu- ally not indicated. An average 8-year follow-up of 29 patients treated without surgery revealed excellent results with no limitations in life- style, whereas surgically treated pa- tients had numerous problems. 11 Persistent subluxation may lead to osteoarthritis. Distal Osteolysis of the Clavicle Osteolysis of the distal clavicle, often bilateral and almost always oc- curring in young adult males, is gen- erally caused by overuse. Cahill 12 re- ported on 46 men with distal osteolysis associated with weight lifting in all but one. A study of elite weight lifters revealed that 28% had distal osteolysis, which is asso- ciated with pain, mild swelling, and tenderness at the acromioclavicular joint. 13 Radiographs demonstrate os- teopenia, subchondral lysis, and cysts (Figure 7). There may be mi- crofractures in the subchondral bone, degenerative changes in the ar- ticular cartilage, chronic inflamma- tion, or fibrosis of the joint. Radio- nucleotide studies demonstrate increased uptake at the distal clavi- cle. The differential diagnosis in- cludes conditions associated with osteolysis, such as hyperparathy- roidism, rheumatoid arthritis, scle- roderma, infection, and neoplasia. The treatment for painful distal osteolysis is modification of the weight-lifting program. When this modification is not successful, the condition may be treated by resec- tion of the distal end of the clavicle, which usually provides pain relief and allows some patients to resume competitive weight lifting. 14 Friedrich’s Disease Occurring more often in young adults, Friedrich’s disease is a rare condition characterized by osteone- crosis of the end of the clavicle. 15 The cause is unknown. The usual clinical presentation is pain with swelling at the sternoclavicular joint. Laboratory findings do not sug- gest infection, although the ESR may be elevated. Radiographs dem- onstrate sclerotic irregularity of the medial or, less often, the lateral end of the clavicle without enlargement of the bone. 16 There also may be flu- id in the adjacent joint (Figure 8). Metachronous involvement of both the medial and lateral clavicle has been described, with osteonecrosis and fibrosis present on microscopic examination. The differential diagnosis in- cludes painful conditions associated Figure 6 Axial computed tomography scan of a patient with anterior and superior subluxation of the left clavicle. The ribs are seen symmetrically, whereas the left clavicle is more anterior than the right and is larger because of anterior and cephalad subluxation. Figure 7 Anteroposterior photograph demonstrating loss of definition and osteolysis of the distal clavicular cortex (arrow). Figure 8 Anteroposterior radiograph demonstrating increased bone density in the proximal clavicle without periosteal new bone formations in a patient with Friedrich’s disease. Nontraumatic Disorders of the Clavicle 208 Journal of the American Academy of Orthopaedic Surgeons with increased density of the end of the clavicle, such as hypertrophic os- teitis and chronic multifocal peri- osteitis. Osteonecrosis is distin- guished radiographically by the lack of periosteal elevation and by in- volvement limited to the ends of the bone. Biopsy for diagnostic purposes usually is not necessary. The treat- ment is expectant, or nonsurgical, management, but excision may be indicated for disabling pain. Hypertrophic Osteitis (Condensing Osteitis) The clinical and radiographic findings and prognostic features of hypertrophic osteitis and condens- ing osteitis are similar, suggesting that these are the same condition. Until clear distinguishing features are described, it is best to consider them as a single entity. Hypertrophic osteitis is an isolat- ed, usually unilateral, painful, scle- rotic lesion with periosteal enlarge- ment of the medial third of the clavicle. The sternoclavicular joint is normal. The condition is de- scribed most often in adults, in fe- males, and on the dominant side, but it has been reported in childhood. It is not associated with acute trauma. The condition is not an infection or neoplasm, but it may resemble ei- ther. 17,18 Some think that hyper- trophic osteitis is an overuse syn- drome. Laboratory abnormalities may in- clude elevation of the ESR and vari- able elevation of the WBC count, and there is an increased uptake of radionuclide in the involved area. Radiographs of hypertrophic osteitis demonstrate enlargement and scle- rosis of the medial third of the clav- icle without involvement of the joint or ossification of adjacent liga- ments (Figure 9, A). Periosteal new bone may be notably prominent. CT scans show increased bone density and bone formation (Figure 9, B), whereas magnetic resonance imag- ing (MRI) findings include loss of the marrow space. Biopsy and culture may not be necessary when findings are typical, although biopsy demon- strates chronic inflammation of the bone and periosteum with thick tra- becula. The differential diagnosis in- cludes disorders with periosteal ele- vation and enlargement of bone, such as Paget’s disease, osteoid os- teoma, infectious disorders, chronic multifocal periosteitis, and neopla- sia. Hypertrophic osteitis responds variably to analgesics, anti-inflam- matory drugs, antibiotics, and mod- ification of activity. Persistently painful lesions have been treated successfully by resection of the me- dial clavicle 19 (Figure 9, C). Chronic Multifocal Periosteitis and Arthropathy Sternocostoclavicular hyperosto- sis (SCCH); synovitis, acne, pustules, hyperostosis, and osteitis (SAPHO); and chronic recurrent multifocal os- teomyelitis (CRMO) have been de- scribed as separate clinical entities, but they share many clinical fea- tures. These conditions have in com- mon nonsuppurative periosteitis with hyperostosis; multifocal in- volvement of the extremities, spine, and pelvis; and a prolonged clinical course with exacerbation and remis- sion. All three conditions may in- volve the clavicle. These syndromes differ somewhat by age of presenta- tion and sites of major involvement. CRMO is generally diagnosed in childhood and often involves the long bones. SAPHO typically pre- sents in adults, has a high incidence of pustular involvement of the palms and soles, and often involves the spine. SCCH involves the anterior chest wall in adults, with less in- volvement of the spine and pelvis. Until there are criteria that clearly separate these three conditions on the basis of etiology, clinical course, or treatment, it is appropriate to de- Figure 9 A, Anteroposterior radiograph of a patient with hypertrophic osteitis. The medial one third of the clavicle is enlarged with increased density. B, Axial computed tomography scan of the clavicle shown in panel A demonstrating increased bone density of the medial clavicle with periosteal thickening. C, Medial third clavicle shown in panel A after removal for intractable pain demonstrating dense cancellous bone. Rodney K. Beals, MD, and Donald D. Sauser, MD Volume 14, Number 4, April 2006 209 scribe them under the common term chronic multifocal periosteitis and arthropathy. A further source of diag- nostic confusion is that each of these conditions has features that may al- low a diagnosis of spondyloarthrop- athy (ie, periosteitis, enthesopathy, sacroiliitis, uveitis, psoriasis, urethri- tis, regional enteritis, and spondyli- tis). These three forms of chronic multifocal periosteitis and arthropa- thy—SCCH, SAPHO, SCCH, CRMO—may be included within the broad definition of spondyloarthrop- athy 20 (Figure 10). SCCH is a painful, chronic, non- suppurative periosteitis involving the sternum, ribs, and clavicle. It is multifocal, bilateral but often asym- metric, and may sequentially affect other joints. It presents in adults with pain, heat, tenderness, and swelling over the medial clavicle and adjacent ribs. It causes hyperostosis of the bones, synovitis of the ster- noclavicular joint, and ossification of ligaments around the clavicle. The periosteitis may be sufficiently se- vere as to cause obstruction of the subclavian veins. SCCH has been de- scribed more commonly in men (es- pecially Japanese) between ages 30 and 50 years. In this setting, 60% of cases are associated with pustules of the palm or soles. SCCH is also asso- ciated with ankylosing spondylitis (32%), vertebral hyperostosis (23%), sacroiliitis (22%), and arthritis of the peripheral joints. 21,22 Radiographs demonstrate bone, joint, and soft- tissue abnormality (Figure 11, A). Hyperostotic involvement of the clavicle is common. Ossification of the costochondral and costoclavicu- lar ligaments and joint involvement to include ankylosis of the sterno- clavicular joint may be present and are best demonstrated by CT (Figure 11, B). SAPHO is a painful, chronic, non- suppurative periosteitis that usually presents in adults. Many patients have only some of the descriptive features. In a survey of 85 patients with SAPHO, 13 had severe acne, 44 had palmar or plantar pustules, and 28 had hyperostosis without skin change. Approximately half of pa- tients with SAPHO have sacroiliitis, and some have inflammatory bowel disease and/or psoriasis. Many have polyostotic involvement; the anteri- or chest wall is a common site. 23,24 In one study, 33% of patients with SAPHO were positive for HLA-B27 antigen. 25 Radiographs demonstrate areas of increased bone density, peri- osteal new bone, and arthritis. Thir- ty percent of these patients have metaphyseal involvement of the long bones, with osteosclerosis, os- teolysis, and periosteal new bone formation. Ossification of the ante- rior vertebral ligaments may be present. CRMO is a painful, inflammato- ry disease of children and young adults that especially affects the long bones but also may involve the spine and clavicle. Girschick et al 26 report- ed on 11 patients, 6 with CRMO that affected the clavicle. Moore et al 27 reported on 11 patients, 3 with CRMO that affected the clavicle. In another study, 28 long-term follow-up of 12 patients with a diagnosis of CRMO revealed that 11 had devel- oped hyperostosis of the vertebra, 7 had sacroiliitis, 4 had peripheral en- thesopathy, and 2 had unilateral ar- thritis of the hip. Palmar or plantar pustulosis was present in about one third of patients, and 11 of the 12 pa- tients met the criteria for diagnosis Figure 10 Spondyloarthropathy SCCH SAPHO CRMO Clavicle Clavicle involvement in chronic multifocal periosteitis and arthropathy. The clavicle may be affected in sternocostoclavicular hyperostosis (SCCH); synovitis, acne, pustules, hyperostosis, and osteitis (SAPHO); and chronic recurrent multifocal osteomyelitis (CRMO), which have overlapping features. They can collectively be called chronic multifocal periosteitis and arthropathy. SCCH, SAPHO, and CRMO each have features that may allow a diagnosis of spondyloarthropathy. Figure 11 A, Anteroposterior radiograph of a patient with chronic multifocal periosteitis and arthropathy demonstrating bilateral sclerotic enlarged clavicles and ossification in soft tissues. B, Axial computed tomography scan of the same patient demonstrating juxta-articular ossification and new bone formation along the clavicle and sternum. Nontraumatic Disorders of the Clavicle 210 Journal of the American Academy of Orthopaedic Surgeons of spondyloarthropathy. 28 Other follow-up studies on patients with CRMO have revealed similar find- ings. 29 Laboratory studies in each of these three conditions have in common variable elevation of the ESR, leuko- cytosis, and elevated C-reactive pro- tein (CRP) level. Bone cultures are negative. The pathology is that of acute inflammation early in the dis- ease and chronic inflammation late in the disease. Radiographs demon- strate periosteitis of various bones, synovitis of joints, and ossification of ligamentous structures around joints. Evaluation of patients suspected of these three diagnoses should in- clude a search for other components of spondyloarthropathy. This search should include a bone scan to iden- tify areas of bone involvement that are not clinically apparent as well as the ESR, WBC count, and CRP level. The differential diagnosis includes other causes of anterior chest wall pain, including costochondritis and fibromyalgia. 30 There is no effective curative treatment for these conditions. The clinical course can be protracted, characterized by exacerbation and remission; however, the condition generally improves over time. Corti- costeroids, sulfasalazine, nonsteroi- dal anti-inflammatory drugs, and methotrexate have been used with variable results. Long-term antibiot- ics generally are not effective except in the presence of pustules. Tonsil- lectomy has been used with some re- ported success. Finally, surgical re- moval of the clavicle has been reported as a treatment of last resort for intractable pain. Osteomyelitis Acute osteomyelitis of the clavi- cle in children and adults is usually a result of Staphylococcus aureus in- fection. Because the clavicle is an unusual site for osteomyelitis, diag- nosis may be delayed. This condi- tion is a rare complication of subcla- vian vein catherization, presenting with local swelling, pain, heat, ten- derness, fever, and elevated ESR and WBC count. Even with antibiotic treatment and surgical drainage, there may be recurrence, fracture, or absorption of the clavicle. 31 Blood cultures often are positive before ra- diographic changes appear. Subse- quent radiographs demonstrate peri- osteal elevation and metaphyseal destruction, findings typical of os- teomyelitis. MRI will demonstrate bone destruction with edema in the bone and adjacent soft-tissue in- volvement. Of 23 infections of the clavicle in children from South Afri- ca, 11 were the result of pyogenic in- fection; 4, tuberculosis; and 8, con- genital syphilis. 32 Suspected acute osteomyelitis is evaluated by WBC, ESR, and CRP laboratory studies and blood and bone cultures. Treatment is by antibiotics and surgical drain- age as clinically indicated. Primary subacute hematogenous osteomyelitis may involve the clav- icle. It occurs in children and in en- vironments of increased host resis- tance and/or decreased bacterial virulence. Appearing most often in the metaphysis of long bones, it is unifocal and presents with mild to moderate pain. 33 When the clavicle is affected, there is prominent peri- osteal expansion of the medial or lat- eral clavicle with increased density and cystic changes. The differential diagnosis of subacute osteomyelitis of the clavicle includes hypertrophic osteitis, chronic multifocal peri- osteitis, and neoplasia. Biopsy often is indicated to clarify the diagnosis. Sternoclavicular Joint Infection Sepsis of the sternoclavicular joint presents with local joint swell- ing, pain, and heat and is aggravated by arm movement. The WBC count and ESR are variably elevated. This condition has been reported in im- munocompromised patients and is associated with drug use. 34 Aspira- tion and culture may reveal unusual organisms. Twenty percent of pseudomonas arthritis has been re- ported to occur at the sternoclavicu- lar joint. 34 Radiographs demonstrate soft-tissue swelling with destructive changes in the joint and adjacent bone. MRI findings include joint de- struction and marrow edema. Diag- nosis is established by joint aspira- tion or biopsy. The differential diagnosis in- cludes rheumatoid arthritis and chronic multifocal periosteitis, dis- tinguished by the unifocal site of in- volvement. Treatment consists of antibiotics, serial aspiration or open drainage and débridement as clini- cally indicated. Acromioclavicular Joint Infection Presenting with symptoms that include local swelling, heat, and pain with shoulder movement, sep- tic arthritis less commonly occurs in the acromioclavicular joint than in the sternoclavicular joint. Infection of the acromioclavicular joint may be a complication of cortisone injec- tion. Laboratory findings include el- evated ESR and WBC count. Radio- graphs demonstrate soft-tissue swelling with destructive bone and joint changes. MRI findings include marrow edema, joint fluid, increased vascularity, and soft-tissue edema (Figure 12). The condition is diag- nosed by joint aspiration or biopsy. The differential diagnosis in- cludes inflammatory and osteolytic disorders such as rheumatoid arthri- tis, hyperparathyroidism, posttrau- matic osteolysis, and gout. Treat- ment consists of antibiotics and serial aspiration of the joint, al- though open drainage and débride- ment may become indicated. Tumors of the Clavicle Tumors of the clavicle are rare. One benign condition occurs when the medial and lateral end of the clavicle, which are preformed in car- tilage, develop osteochondroma. 35 Other reported benign conditions in the clavicle include osteoid osteo- Rodney K. Beals, MD, and Donald D. Sauser, MD Volume 14, Number 4, April 2006 211 ma, aneurysmal bone cyst (Figure 13), neurofibromatosis, hemangio- ma, eosinophilic granuloma, rickets, acromegaly, Paget’s disease, fibrous dysplasia, and histiocytosis. 36 Malignant tumors of childhood that involve the clavicle include os- teosarcoma, Hodgkin’s disease, leukemia, and Ewing’s sarcoma. The clavicle is involved in 3% of children with Ewing’s sarcoma, in 2% of children with osseous lesions of Hodgkin’s disease, and in <1% of patients with osteosarcoma. Radiation-induced tumors also oc- cur because of the frequency in which the clavicle is included in the radiation field for malignant tumors of the head and neck. 37 Malignant tumors of the clavicle reported in adults include multiple myeloma, lymphoma, angiosarcoma, osteosar- coma, and chondrosarcoma. Meta- static disease may involve the clav- icle (Figure 14). Radiographs may demonstrate a discrete tumor with the characteris- tic features of a tumor, but the changes often include sclerosis, peri- osteal elevation, lysis, or combina- tions of these. Biopsy is recommend- ed when the findings do not clearly fit a known benign condition. Surgical Excision of the Clavicle The clavicle or part of it may be excised as treatment for disease. The degree of resection is determined by the nature and site of the pathology. The proximal clavicle medial to the costoclavicular ligaments and the distal clavicle and lateral to the cor- acoclavicular ligaments, can be re- sected without causing mechanical instability. Excision of the distal end of the clavicle for osteoarthritis is the most common surgical proce- dure and may also be indicated for infection, tumor, or osteolysis. Re- section of <0.5 cm runs a risk of bone impingement with motion, whereas greater resection exacerbates the risk of increased mobility and associated pain. Care is indicated to restore the acromioclavicular ligaments when possible because they control antero- posterior movement of the clavicle. 38 Excision of the medial end of the clavicle is less common but may be indicated for infection, hypertrophic osteitis, or tumor. 39 Excision is not the optimal treatment of chronic an- terior subluxation because the im- pairment may not war rant surgery, and the surgical results may be poor. 11 When possible, resection of the medial clavicle should include reconstruction of the costoclavicular ligaments by attaching the residual periosteum to the first rib. Larger resection of the medial or lateral clavicle, the mid clavicle, or the entire clavicle may result in good function but is not predict- able. 40 It may be indicated for infec- tion or tumor or to expose underly- ing pathology. Excision of the entire clavicle has a venerable history, hav- ing been first performed in 1813 for tuberculosis. 41 Function following removal may be surprisingly good and, when the periosteum is intact, may be associated with regrowth. Reconstruction of the proximal hu- merus with the clavicle has been re- ported after tumor resection. 42 For disability following claviculectomy, reconstruction of the middle or en- tire clavicle using a vascularized rib graft has been described. 43 Summary Nontraumatic conditions of the clavicle are challenging to diagnose and manage because of the varied presentation and manifestation, con- fusing terminology, lack of knowl- edge of the natural history, and diffi- culty in discerning cause. Clavicle disorders that typically are found in infancy and early childhood include fracture of the clavicle, associated with delivery or the result of a syn- drome involving chromosomes 11,18, and 22; congenital pseudar- throsis of the clavicle, usually diag- nosed because of the anterior prom- Figure 13 Anteroposterior radiograph demonstrating massive expansion of the cortex of the medial clavicle in a patient with aneurysmal bone cyst. Figure 14 Anteroposterior radiograph after biopsy demonstrating diffuse lytic involvement of the distal clavicle in a patient with a hemangioendothelioma. Figure 12 T1-weighted coronal MRI scan with fat saturation postgadolinium demonstrat- ing fluid in the acromioclavicular joint, destruction of the adjacent clavicle and acromion, and hyperemia in the marrow and adjacent soft tissues in this patient with septic arthritis. Nontraumatic Disorders of the Clavicle 212 Journal of the American Academy of Orthopaedic Surgeons inence of the mid clavicle or asymmetry of the shoulder girdle in a mobile clavicle; infant cortical hy- perostosis, with painful periosteal el- evation; cleidocranial dysplasia, generalized bone dysplasia with bi- lateral congenital absence of the mid clavicle; and short clavicle syn- drome, which involves bilateral symmetrical shortening of the clav- icle. Nontraumatic disorders of the clavicle in childhood and adulthood include anterior subluxation of the sternoclavicular joint, which is uncommon and sometimes associat- ed with throwing or gymnastics; dis- tal osteolysis of the clavicle, typical- ly a result of overuse; Friedrich’s disease, with osteonecrosis at the end of the clavicle; hypertrophic os- teitis, which may be the same as condensing osteitis; osteomyelitis, a result of hematogenous staphylococ- cus; chronic multifocal periosteitis and arthropathy, which includes SCCH, CRMO, and SAPHO; and tu- mors of the clavicle. Management can be varied and in- clude symptomatic and expectant management; modification of weight- bearing activities, such as weight lift- ing; drug therapies, including nonste- roidal anti-inflammatory drugs and antibiotics; or surgical treatment, in- cluding resection or excision. 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Disorders of the Clavicle 206 Journal of the American Academy of Orthopaedic Surgeons Cleidocranial Dysplasia Cleidocranial dysplasia (absent clavicle) is a generalized bone dys- plasia that usually. of cleidocranial dysplasia associated with severe mental retar- dation and absence of the thumbs, unilateral complete absence of the clavicle, and a rare autosomal reces- sive form of cleidocranial. childhood, such as birth fracture, infantile cortical hyperostosis, congenital pseudarthrosis, cleidocranial dysplasia, and short clavicle syndrome. Other nontraumatic disorders occur in both children