Management of distal humeral coronal shear fractures

Abstract

Coronal shear fractures of the distal humerus are rare, complex fractures that can be technically challenging to manage. They usually result from a low-energy fall and direct compression of the distal humerus by the radial head in a hyper-extended or semi-flexed elbow or from spontaneous reduction of a posterolateral subluxation or dislocation. Due to the small number of soft tissue attachments at this site, almost all of these fractures are displaced. The incidence of distal humeral coronal shear fractures is higher among women because of the higher rate of osteoporosis in women and the difference in carrying angle between men and women. Distal humeral coronal shear fractures may occur in isolation, may be part of a complex elbow injury, or may be associated with injuries proximal or distal to the elbow. An associated lateral collateral ligament injury is seen in up to 40% and an associated radial head fracture is seen in up to 30% of these fractures. Given the complex nature of distal humeral coronal shear fractures, there is preference for operative management. Operative fixation leads to stable anatomic reduction, restores articular congruity, and allows initiation of early range-of-motion movements in the majority of cases. Several surgical exposure and fixation techniques are available to reconstruct the articular surface following distal humeral coronal shear fractures. The lateral extensile approach and fixation with countersunk headless compression screws placed in an anterior-to-posterior fashion are commonly used. We have found a two-incision approach (direct anterior and lateral) that results in less soft tissue dissection and better outcomes than the lateral extensile approach in our experience. Stiffness, pain, articular incongruity, arthritis, and ulnohumeral instability may result if reduction is non-anatomic or if fixation fails.

Coronal shear fractures of distal humerus: Diagnostic and treatment protocols

“…The anteroposterior view radiograph in most cases cannot show the fracture fragment and a lateral view is essential [1][2][3] . The oblique view also details more of the injury hence standard AP, lateral and radiocapitellar views should be done in every case.…”

“…The capitello-trochlear fracture or type Ⅳ McKee [10] is typically described as double arc sign on lateral view but this sign is not pathognomonic of this type as it may not be present in all cases. A simple capitellar fracture on radiographs turns out to be a complex fracture intraoperatively with most of them having part of trochlea involved [1][2][3][4] . This sign thus may be misleading as isolated trochlea also present as half-moon or double arc sign [14] .…”

“…Imaging of the joints above and below the level of injuries will reveal bony injuries and soft tissues should be judged by clinical evaluation and magnetic resonance imaging. Plain radiographs have a 66% sensitivity and a negative predictive value of 63%-67% for fractures extending to trochlear region [1,2] . The inability to determine the extent, thickness and size of the fragment in standard radiographs has necessitated some authors to propose a two and three dimensional computed tomography (CT) scan in order to establish a better preoperative description of the injury and thorough analysis of anatomical features of the fracture [1][2][3][4][5][6][7] .…”

“…Coronal shear fractures of the distal humerus involving capitellum and trochlea account for less than 1% of elbow fractures [1,2] . These injuries result from axial loading of the capitello-trochlear area by the forces transmitted through the radial head and could be associated with more complex distal humeral fractures and dislocation with concomitant ligamentous injuries [1,3] .…”

“…These injuries result from axial loading of the capitello-trochlear area by the forces transmitted through the radial head and could be associated with more complex distal humeral fractures and dislocation with concomitant ligamentous injuries [1,3] . The complexity of these fractures in recent times has been better appreciated by digital imaging and computed tomographic scans [3][4][5][6] .…”