25 Acute Scaphoid Fractures Abstract This chapter describes the “care delivery value chain” for acute scaphoid fractures. The most common mechanism of injury is axial loading across a hyperextended and radially deviated wrist. A scaphoid fracture should be suspected if there is tenderness in the anatomical snuff box and/or on palpating the scaphoid tuberosity with radial sided pain increasing on radial or ulnar deviation and/or pain on longitudinal compression of the thumb. Adequate radiographic views, usually four or five, of the wrist are needed. The alternative is to investigate using a magnetic resonance imaging (MRI) scan or a fine-cut computed tomography (CT) scan. An undisplaced scaphoid fracture will heal anatomically when immobilized in a below-elbow plaster cast with the thumb free and may need this for only 4 weeks. We almost never immobilize a patient in a cast longer than 6 to 8 weeks. Should a fracture be minimally displaced (≤1 mm), the surgeon may also consider percutaneous screw fixation. The benefits of internal fixation are that the fracture is stabilized usually sufficiently to avoid external immobilization, but the patient is exposed to surgical risks. Fractures displaced ≥2 mm and proximal pole scaphoid fractures that have a high risk of nonunion (30%) or avascular necrosis may need internal fixation. The care delivery value chain describes the six clinical stages in managing such fractures. Keywords: scaphoid fracture, diagnosis, treatment, outcome The word “scaphoid” derives from the Greek word “σκαφωıδεζ” meaning “boat shaped.” It has an incidence of 12.4 to 43 in 100.000.1–4 It is a wonder that a fracture of such a small bone can cause so much trouble. In the United Kingdom, injuries to the hand cost the tax payer over £100 million each year.5 Each stage consists of the following: patient involvement (what patients need to be educated about), measures needed to be collected, patient care activities taking place, and finally delivery of care (what activities of care occur). Porter emphasized: The care delivery value chain highlights questions such as how each activity in the care cycle is best performed, and by whom; how the effectiveness of one activity is affected by others; what sets of activities are best performed within a single care center and which are shared; how the patient is best reached over time; how patients should be informed and engaged in their own care and what patient overall outcomes and risk factors need to be measured to guide care decisions. This chapter will describe each of the stages of the care delivery value chain for the acute scaphoid fracture. The most common mechanism of injury is axial loading across a hyperextended and radially deviated wrist.7 This is best illustrated by fractures occurring in sport with the incidence of wrist injuries constituting 3 to 9% of all sport injuries.8 The scaphoid fracture is a common injury particularly in American football and basketball and it is estimated that 1 in 100 college football players will sustain a fracture of the scaphoid.9 Recent studies show that the use of wrist braces has reduced the incidence of carpal fractures.10,11 Various “landing strategies” used in martial arts have a significant effect on reducing impact load during a fall and may be effective in preventing carpal injuries.12 Contact sport athletes should probably receive education on injury prevention. Having sustained the injury, the patient attends the emergency department (ED) where a careful history is taken and examination performed by a doctor or a non-medically qualified but trained clinician. The first question that needs to be answered is how severe the injury is. The more severe it is, the likelier that there will be a bony injury. The second question is whether there is radial-sided wrist pain. Third, where is the pain precisely situated? Young patients often underestimate an injury and assume it is a “sprain” that will settle quickly. The salient features of examining a scaphoid fracture include tenderness in the anatomical snuff box (ASB) and/or on palpating the scaphoid tuberosity (ST) with radial-sided pain increasing on radial-ulnar deviation and/or pain on longitudinal compression (LC) of the thumb. These clinical signs are “inadequate indicators” of scaphoid fractures when used alone and should be combined to achieve a more accurate clinical diagnosis.13 Parvizi et al13 showed that at the initial assessment, within 24 hours of injury, all cases with a scaphoid fracture have ASB and ST tenderness and pain on longitudinal compression, a sensitivity of 100%. The corresponding specificities for these signs at the initial examination were 19, 30, and 48% for ASB, ST, and LC, respectively. When all three signs are positive at the initial examination, the specificity improves to 74%, so three out of four patients will have a fracture. The fourth question is what imaging is needed. When assessing the imaging for a scaphoid injury, the following questions must be answered by the clinician. First, is the scaphoid fractured? This is verified with adequate views, usually four or five, of the wrist ( The answers to the four questions on imaging confirm the presence or absence of a scaphoid fracture. In patients who do not have a fracture, the decision is then to either discharge, image further, or review again (if a scaphoid fracture is clinically suspected, defined as a patient with (1) an appropriate injury, (2) pain on the radial side of the wrist, (3) tenderness or pain on the tests mentioned earlier, and (4) no obvious fracture seen on at least four good-quality radiographic views). Strong clinical suspicion of a scaphoid fracture should include more than one of the signs mentioned earlier.13 Fig. 25.2 The usual radiographic views are illustrated. (a) Posteroanterior view. (b) Elongated scaphoid view. (c) Lateral view. (d) Semiprone view. (e) Semisupine radiographic view. In patients that do have a fracture, the location and amount of displacement needs to be quantified as this will determine the treatment pathway. A fracture is defined as displaced if the step or gap is ≥1 mm and the gap is usually seen at the radial or dorsal cortical surface on an elongated scaphoid, the PA, or oblique radiographic views.14 Only parts of classifications, such as the Herbert classification, apply to the acute fracture. Types A and B describe some of the attributes discussed earlier. Types B1 and B2 are based on the line of the fracture, while proximal fractures (B3), fracture–dislocations (B4), and comminution (B5) account for the other types.15 These descriptions do not clearly assist in decision making. The cornerstone of scaphoid fracture management is stabilization. This can be achieved either with a plaster cast or with screw fixation. The objective is to limit movement at the fracture site so that it can heal. After being reviewed in the ED, if a scaphoid fracture is clinically suspected (defined earlier), the patient should be informed about the possibility of a fracture, placed in a removable splint, and be given a follow-up appointment in an appropriate clinic. The alternative is to image further using either a MRI scan or a fine-cut CT scan to resolve the question on whether there is a fracture. After an interval of around a couple of weeks, a thorough examination and repeat scaphoid radiographs should be taken after removing the plaster to identify those with persistent symptoms and signs. If radiographs do not explain the pain, further imaging may be required. In the absence of a fracture, either the patient can be treated as a soft-tissue injury of the wrist and be discharged with wrist exercises or a follow-up appointment can be arranged in 6 weeks to ensure a significant soft-tissue injury is not missed. We usually discharge patients with advice if there is no clinical indication of a ligament injury. Patient information leaflets should be provided for further education of the possibility of a fracture and what to look out for in the first few weeks with the patient provided with direct access back to the treating team if symptoms persist. When the patient with a fracture is reviewed in fracture clinic, a more detailed history should include handedness, past medical history, medication taken (including steroids), past injury/fracture/surgery to the affected wrist, social history (smoking status, alcohol consumption, hobbies), occupation, and finally level of sporting activity. Smoking cessation should be re-emphasized due to higher risk of nonunion in all fractures.11 An undisplaced scaphoid fracture will heal anatomically when immobilized in a below-elbow plaster cast with the thumb free and may need this for only 4 weeks.16 About 50% of units in the United Kingdom (including the authors’) use a below-elbow cast,17 which leaves the thumb free and, by permitting pinch, allows better function,18 whereas the other 50% continue to use a traditional scaphoid plaster that immobilizes the thumb. With the thumb immobilized, the additional restriction of movement of the scaphoid is very small, so not much is gained, but patient disability is increased. The thumb can be immobilized in two positions. A functional position is when the thumb is kept in a position of opposition to allow pulp pinch and tripod pinch. A dysfunctional position is when the thumb is placed so pinch is not possible. This only permits the hand to be used to assist or to hook a bag. This position does not allow prehension and the patient has very limited capacity to perform even activities of daily living. There are two groups of patients who may require restricting the function of the thumb: patients in whom compliance is uncertain and those with marked ligamentous laxity in whom even light pinch may cause scaphoid movement. In summary, hand function is “good” in a below-elbow cast with the thumb left free, “adequate” in a scaphoid cast in functional position, “restricted” in a scaphoid cast in a dysfunctional position, and “hugely compromised” in an above-elbow cast ( A discussion regarding cast care/hygiene and possible problems should take place and written instructions provided. In particular, we ask patients to return if the cast softens enough to allow wrist movement and explain that this may permit wrist and scaphoid movement and could result in a breakdown of the healing process. Proximal pole scaphoid fractures have a high risk of nonunion (30%)18 or avascular necrosis (AVN). An unstable scaphoid fracture is defined as one with displacement of the fracture fragments ≥1 mm on any view17 and the surgeon may want to discuss with the patient regarding treating this in a cast or operatively. Immobilization in a cast for 6 weeks will result in union of 80 to 85% of displaced fractures of the scaphoid.18 For some fractures, internal fixation is considered appropriate and the decision making must be agreed with the patient. The procedure must be explained and the patient should understand the benefits and risks of surgery and clearly know the alternative to surgery. The benefits are that the fracture is stabilized usually sufficiently to avoid external immobilization. Many patients assume that fixing the fracture means that they can resume activity, regardless of its demands on the wrist, as if the fracture has “healed” and do not appreciate that fixation is only an internal splint that holds the alignment of bones as the normal processes of healing occur.
25.1 Introduction
Fig. 25.1 depicts the care delivery value chain for acute scaphoid fractures, which is an adaptation to Michael Porter’s value chain for medical conditions.6 This illustrates the “journey” through which the patient “travels” after sustaining an acute scaphoid fracture. It consists of six stages: preventing, diagnosing, preparing, intervening, recovering/rehabilitating, and finally monitoring/managing.
25.2 Trauma Mechanism
25.3 Clinical Signs and Tests
25.4 Investigatory Examinations
Fig. 25.2; posteroanterior [PA] and/or an elongated scaphoid view, usually obtained with ulnar deviation of the pronated hand; lateral; semipronated oblique; and semisupinated oblique views). Second, what is the “state” of the fracture? Is it undisplaced, displaced, or complicated? Third, what is the cause of the complicated fracture? Is it a ligamentous injury or is it associated with another bony injury, and, fourth, if so, is it associated with subluxation or dislocation? The fracture dislocation should be promptly reduced in the ED after being given appropriate analgesia and a local anesthetic block if needed. This injury will not be dealt with in this chapter.
25.5 Alternative Treatment Options
25.5.1 Clinically Suspected Scaphoid Fracture
25.5.2 Cast
Fig. 25.3). That is why there is no place for an above-elbow cast as this disables the patient.
25.5.3 Fix
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