Summary Distal clavicle fractures are traumatic injuries usually caused by direct trauma to the shoulder from a fall in adults. Diagnosis is confirmed with standard shoulder radiographs and a 15° cephalic tilt view (zanca view). Treatment is immobilization or surgery, depending on the displacement and stability of the distal clavicle, as determined by whether coracoclavicular (CC) ligaments (trapezoid and conoid) are intact. Epidemiology Incidence common clavicle fractures account for 2.6-4% of all adult fractures Demographics more commonly in older or osteoportic patients less common in pediatric patients Anatomic location 10-25% of all clavicle fractures occur in the distal third segment Etiology Pathophysiology mechanism similar mechanism to midshaft clavicle fractures usually occurs after a direct compressive force is applied to the shoulder, i.e. after a fall or trauma pathoanatomy fracture displacement corresponds to fracture location (e.g. extra-articular vs. intra-articular) fracture pattern (e.g. simple vs. comminuted) integrity of the coracoclavicular ligments conoid (medial) and trapezoid (lateral) provide primary resistance to superior displacement of the lateral clavicle age (e.g. pediatric patients usually have an intact periosteal sleeve) deforming forces include Associated conditions rare but may include floating shoulder scapulothoracic dissociation should be considered with significantly distracted or widened fractures rib fracture pneumothorax neurovascular injury Anatomy Acromioclavicular joint anatomy AC joint stability static stabilizers acromioclavicular (AC) ligament provides anterior/posterior stability inserts 6 mm from distal end of clavicle components superior inferior anterior posterior superior ligament is strongest, followed by posterior coracoclavicular (CC) ligaments (trapezoid and conoid) provides superior/inferior stability components trapezoid ligament (lateral) inserts 2 - 3 cm from distal end of clavicle attaches to the trapezoid tubercle, which is anterolateral to the conoid tubercle conoid ligament (medial) inserts 4-4.5 cm from distal end of clavicle in the posterior border attaches to the conoid tubercle, which is posteromedial to the trapezoid tubercle most important for vertical stability capsule dynamic stabilizers deltoid trapezius Classification Neer Classification Type I Extra-articular fracture occurring lateral to CC ligaments Conoid and/or trapezoid ligament remains intact Minimal displacement Stable Nonoperative Type IIA Fracture occurs medial to CC ligaments Conoid and trapezoid ligament remain intact Significant medial clavicle displacement Unstable - Up to 56% nonunion rate with nonoperative management Operative Type IIB two fracture patterns (1) fracture occurs either between CC ligaments - Conoid ligament torn - Trapezoid ligament intact (2) fracture occurs lateral to CC ligaments - Conoid ligament torn - Trapezoid ligament torn Significant medial clavicle displacement Unstable - Up to 30-45% nonunion rate with nonoperative management Operative Type III Intra-articular fracture occurring lateral to CC ligaments and extending into AC joint Conoid and trapezoid ligaments remain intact Minimal displacement Stable - Patients may develop post-traumatic AC arthritis Nonoperative Type IV Physeal fracture that occurs in the skeletally immature Conoid and trapezoid ligaments remain intact Displacement of lateral clavicle occurs superiorly through a tear in the thick periosteum (clavicle pulls out of periosteal sleeve) Stable Nonoperative Type V Comminuted fracture pattern Conoid and trapezoid ligaments remain intact Significant medial clavicle displacement Usually unstable Operative AO Classification Type A = nondisplaced + intact CC ligaments A1 = extra-articular A2 = intra-articular Nonoperative Type B = displaced + intact CC ligaments B1 = extra-articular B2 = comminuted Nonoperative vs. Operative Type C = displaced + torn CC ligaments C1 = extra-articular C2 = intra-articular Operative Presentation Symptoms anterior shoulder pain Physical exam swelling, ecchymosis, tenderness to palpation AC joint deformity may have tenting of skin (impending open fracture) perform careful neurovascular exam suprascapular nerve is at risk of injury can see weakness of external rotation with the arm in adduction Imaging Radiographs recommended views upright AP of bilateral shoulders axillary lateral 15° cephalic tilt (zanca view) helps to determine superior/inferior displacement may consider having the patient hold 5-10 lbs of weight in the affected hand CT views coronal, saggital, axial 3D reconstruction views findings may help evaluate displacement, shortening, comminution, articular extension, and nonunion Differential Clavicle shaft fractures Pediatric medial clavicle physeal injury Pediatric distal clavicle physeal injury Acromioclavicular separation Treatment Nonoperative sling immobilization with gentle ROM exercises at 2-4 weeks and strengthening at 6-10 weeks indications stable fractures (Neer Type I, III, IV) pediatric distal clavicle fractures (skeletally immature) Operative open reduction internal fixation indications absolute open or impending open fractures subclavian artery or vein injury floating shoulder (distal clavicle and scapula neck fractures with > 10mm of displacement) symptomatic nonunion relative unstable fracture patterns (Neer Type IIA, IIB, V) brachial plexus injury (questionable because 66% have spontaneous return) closed head injury seizure disorder polytrauma patient Techniques Sling Immobilization technique immobilize using sling or figure-of-eight brace prospective studies have not shown a difference in functional or cosmetic outcomes between sling and figure-of-eight braces no attempt at reduction should be made begin gentle range of motion exercises after 2-4 weeks strengthening exercises begin at 6-10 weeks outcomes nonunion (~15%) risk factors Neer group II (up to 56%) disrupted CC ligaments advanced age female gender poorer cosmesis Open Reduction Internal Fixation techniques limited contact dynamic compression plate position beach chair vs. supine approach superior approach to AC joint temporary fixation with k wires instrumentation locking plates precontoured anatomic plates technique need larger distal fragment for multiple locking screws > 3-4 bicortical screws into medial fragment to reduce the risk of screw pull-out hook plate position beach chair vs. supine approach superior approach to AC joint temporary fixation with k wires instrumentation hook plates vary in hook depth and number of holes proper hook depth ensures the AC joint is not over- or under-reduced technique hook plates are generally used when there is insufficent bone in the distal fragment for conventional clavicle plate fixation hook should be placed posterior to AC joint and positioned as far lateral as possible to avoid hook escape > 3-4 bicortical screws should be placed into the proximal (medial) fragment to reduce the risk of screw pull-out requires a second procedure for hook plate removal other options AC joint spanning fixation usually used as an alternative to hook plates transacromial fixation tension band wire intramedullary screw fixation coracoclavicular ligament repair/reconstruction modified Weaver-Dunn procedure primarily used for AC dislocations can also be used for distal clavicle fractures with an easily excisable fragment and transferable CA ligament advantages higher union rates faster time to union improved functional outcome/less pain with overhead activity decreased symptomatic malunion rate improved cosmetic satisfaction disadvantages increased risk of need for future procedures (e.g, removal of hook plate) symptomatic hardware infection postoperative rehabilitation early sling for 7-10 days followed by active motion late strengthening at ~6 weeks when pain-free motion and radiographic evidence of union full activity including sports at ~3 months hardware removal considered usually after 3 months Complications Nonoperative treatment nonunion (~15%) risk factors comminution displacement Z deformity female older smoker distal third clavicle > middle third clavicle treatment if asymptomatic, no treatment necessary if symptomatic, ORIF with plate and bone graft (particularly atrophic nonunion) AC joint arthritis risk factors Neer Type I and III treatment distal clavicle resection Operative treatment hardware prominence ~30% of patient request plate removal superior plates associated with increased irritation hardware removal most common with hook plates neurovascular injury (3%) superior plates associated with increased risk of subclavian artery or vein penetration subclavian thrombosis nonunion (1-5%) infection (~4.8%) mechanical failure (~1.4%) pneumothorax adhesive capsulitis 4% in surgical group develop adhesive capsulitis requiring surgical intervention