68: Percutaneous Screw Fixation of Scaphoid Fractures

Procedure 68 Percutaneous Screw Fixation of Scaphoid Fractures



Louis W. Catalano, III , Christopher M. Jones


imageSee Video 50: Screw Fixation of Scaphoid Fracture



Indications




image Nondisplaced scaphoid fractures


image Displaced scaphoid fractures for which a closed reduction or K-wire-assisted reduction can be performed


image If anatomic reduction of the fracture is not possible by closed means, percutaneous fixation should not be attempted. Instead, open reduction is preferred.



Examination/Imaging



Clinical Examination




image Fractures of scaphoid are frequently missed in the emergency room or dismissed by the patient as a wrist sprain. Thus, the physician must have a high suspicion in young and middle-aged patients who present with wrist pain after a fall on an outstretched hand.


image General dorsoradial edema and focal snuffbox tenderness are highly suggestive of an acute scaphoid fracture (Fig. 68-1).


image The distal pole of scaphoid may be tender to palpation (Fig. 68-2).


image Axial compression of thumb may also produce pain.


image

FIGURE 68-1


image

FIGURE 68-2



Imaging




image The initial posteroanterior (PA) and lateral radiographs may fail to demonstrate a scaphoid fracture (Fig. 68-3). The incidence of false-negative radiographs for acute fractures has been shown to be up to 25%.


image Additional helpful radiographic views include (1) clenched-fist PA, which can exaggerate a fracture deformity and help make a diagnosis; (2) ulnar-deviated PA that positions the scaphoid in extension showing the waist more clearly (Fig. 68-4); and (3) pronated oblique view.


image Magnetic resonance imaging (MRI) is highly sensitive for making the diagnosis—cortical disruption with bone marrow edema is diagnostic. For chronic injuries, MRI is valuable in assessing proximal pole vascularity (Fig. 68-5).


image Although radiographs are usually sufficient for preoperative planning, computed tomography (CT) can be helpful in further delineating the fracture pattern.


image

FIGURE 68-3


image

FIGURE 68-4


image

FIGURE 68-5



Surgical Anatomy




image The scaphoid is the largest bone in the proximal carpal row, and its axis lies about 45 degrees to the longitudinal axis of the wrist.


image Eighty percent of the scaphoid surface is covered by articular cartilage, leaving limited space for vascular supply.


image The scaphoid articulates with the trapezoid, trapezium, capitate, lunate, and radius and serves as a mechanical link between the proximal and distal carpal rows.


image Multiple intrinsic and extrinsic ligaments attach to the scaphoid (Fig. 68-6). The most important is the radioscaphocapitate, which provides an axis on which the scaphoid flexes.


image A dorsal groove courses the length of the scaphoid and provides attachment points for ligaments and blood vessels.


image A dorsal branch of the radial artery provides 70% to 80% of the blood supply (Fig. 68-7).


image A second nutrient artery enters volarly and supplies only the distal pole.


image There is no nutrient artery to the proximal pole; thus, it is susceptible to avascular necrosis when fractured.


image

FIGURE 68-6


image

FIGURE 68-7



Positioning




image The patient is positioned supine on the operating room table with the arm abducted on a radiolucent hand table.


image A minifluoroscope is positioned vertically at the end of the hand table with the image intensifier under the table.



Positioning Equipment




• A towel roll can be used to position the wrist in extension for a volar approach or in flexion for a dorsal approach.

Related posts:

28: Pronator Teres Rerouting 34: Reconstruction of the Central Slip with the Transverse Retinacular Ligament for Boutonnière Deformity 32: Crossed Intrinsic Tendon Transfer 26: Reconstruction of Key Pinch in Tetraplegia Patients 33: Correction of Swan-Neck Deformity in the Rheumatoid Hand 89: Total Wrist Fusion

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Mar 5, 2016 | Posted by in Hand surgery | Comments Off on 68: Percutaneous Screw Fixation of Scaphoid Fractures

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