Fractures of the Clavicle

February 1 2005 Terry R. Yochum, Fellow, Chad J. Maola
Fractures of the Clavicle
February 1 2005 Terry R. Yochum, Fellow, Chad J. Maola

History The young patient fell on an out­stretched arm while playing football. Discussion The "S" shape and normal overlap with the upper ribcage renders the clavicle a difficult structure to evaluate on straight anteroposterior projections. The most optimum view is anteroposterior projec­tions with 15 degrees cephalad tube an-gulation. Weights (10-15 pounds) may be held to aid in detecting undisplaced fractures. The exposure factors should be approximately half of that utilized in standard shoulder projections, to prevent overexposure. Radiological Features Generally, a clavicle fracture follows di­rect trauma and is the most common bone fractured during birth and in childhood. Medial Clavicle Fractures This is the least common site, represent­ing only approximately 5% of all clavicle fractures.1 These are difficult to observe and usually require CT scans. Middle Clavicle Fractures This is the most common site, repre­senting approximately 80% of all clavicle fractures.1 A force applied to the distal end of the "S" shaped clavicle creates a shearing effect at the middle third, pro­ducing the fracture. The fracture is usu­ally complete, with the medial fragment elevated by the action of the sternocleido-mastoid muscle, and the lateral fragment depressed by the weight of the shoulder and upper extremity. In addition to mis- alignment, an overlap at the fracture site is common, with the distal fragment usually ly­ing below the medial frag­ment. Healing is often asso­ciated with extensive callus formation. Lateral Clavicle Fractures These account for approximately 15% of all clavicle fractures.' There are three varieties: undisplaced; displaced, where the distal fragment moves anterior and inferior; and 3) articular surface extension. Whenever a fracture of the lateral third is identified, weight bearing stress views should be obtained to clarify the status of the coracoclavicular ligaments.2 Notably, fractures that extend into the joint fre­quently precipitate the onset of degen­erative arthritis. Complications of Clavicle Injuries Childhood clavicular fractures usually heal without sequelae; however, in adults, the incidence of complications increases. Neurovascular Damage. Associated injury to the underlying neurovascular structures most frequently involves the subclavian artery, less com­monly the vein and, occasionally, the bra-chial plexus and sympathetic chain.' Com-pressive effects from the hypertrophic callus can also precipitate pressure-related neurovascular disturbances.1-4 Nonunion A failure to unite the fracture requires surgical fixation. The key signs of non­union are located at the fracture margins, where sclerosis, rounding, and a smooth contour will be visible. Malunion In the presence of fragment overlap and massive callus formation, a cosmetic de­formity may result. Correction requires osteotomy, realignment and fixation. Degenerative Arthritis Painful degenerative arthritis frequently follows intra-articular fractures of the clavicle. This is evidenced by loss of joint space, sclerosis and osteophyte forma­tion. Post-Traumatic Osteolysis A peculiar bone response to clavicular injury is resorption of the distal segment, usually 1 -3 mm, but never more than 2-3 cm. The initiating injury may be relatively minor, often lacking the severity of that required to cause a fracture or disloca­tion. It first becomes radiologically vis­ible 2-3 months after injury. The precise mechanism is uncertain, although syn-ovial hypertrophy suggests inflammatory osteoclastic activity.5 Pain is mild to mod­erate, while the disorder takes a self-limit­ing course over a number of months. The earliest radiographic sign in the de­velopment of osteolysis is a cystic rar­efaction of the clavicular subarticular cor­tex, followed by cortical dissolution.5-6 The joint appears wide and the clavicular surface is frayed and irregular or cup-shaped. With healing, there are varying degrees of bony reconstitution to com­plete restoration of structure to a perma­nently tapered distal clavicle and in­creased joint space. ► See pg 61 for References M Dr. Terry R. Yovhutn is a second-generation chiropractor ami a cum iaude graduate of the National College of Chiropractic, where he subsequently completed his radi­ology specialty. He is currently Di­rector of the Rocky Mountain Chi­ropractic Radiological Center, in Denver. CO. an Adjunct Professor of Radiology at the Los Angeles College of Chiropractic. as well as an instructor of Skeletal Radiology at the Uni­versity of Colorado School of Medicine, Denver. CO. Dr. Yochum is, also, a consultant fo Health Care Mamtfac- luring Company that offers a Stored Energy xvstctn. For more information. Dr. Yochum can he reached at: 103-940-9400 or In e-mtiil at [email protected]. Dr. Child Mania is a 1999 Ma-gna Cum Laude graduate of Na­tional College ql Chiropractic. ► Figure 1. Note the complete fracture of the midshaft of the clavicle