Acute Scaphoid Waist Fracture in the Athlete

Key points

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A high index of suspicion for a scaphoid fracture is required in athletes with a wrist sprain.
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Nonoperative options, and the complications seen with surgery, should be discussed in detail with the athlete when choosing a treatment regimen.
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Operative fixation of scaphoid waist fractures in athletes may lead to a shorter time out of sport and a quicker return to function.

Introduction

Scaphoid fractures are the most common carpal injury and provide a significant challenge in management ( Figs. 1–6 ). In the athlete, specifically, scaphoid fractures lead to 2 significant challenges: (1) the difficulty of making an accurate, early diagnosis and (2) the need for early return to play.

Diagnosis of scaphoid fractures is a challenge in the general public, with no true gold standard test to confirm a diagnosis. In an athlete, it is even more complicated by the athlete’s approach to injury. Scaphoid fractures can be associated with lower-energy injuries that do not seem significant to many athletes. The level of posttraumatic symptomatology can seem minimal, with nagging wrist pain that is not completely disabling. The athlete’s mentality frequently ignores these symptoms and assumes that these will resolve spontaneously, as so many other trivial injuries have in the past. This can lead to a delayed or missed diagnosis.

The second challenge occurs when scaphoid fractures are identified. Management that minimizes immobilization and allows early return to sport is necessary to maximize an athlete’s career. Athletes’ careers, whether professional, collegiate, or high school, are brief, and management of their injuries requires an understanding of the specific time table under which their lives are managed. Shared decision making is necessary to optimize the outcome for an individual athlete.

Epidemiology

Scaphoid fractures account for 10.6% of all hand fractures (including finger and metacarpal) and account for approximately 66% of all carpal fractures. The rate of scaphoid fracture is approximately 12 per 100,00 in the population as a whole. In collegiate football players, however, the rate of scaphoid fractures may approach 1:100. They have been reported to be nearly 8 times more common in male athletes than in female athletes but, more recently, rates of injury were much closer in men and women, with a ratio of only 2:1. It was hypothesized by the authors that the relative increase in female scaphoid fractures may be due to a higher level of participation in sports.

History and examination

A fall on an outstretched hand, especially with the hand in a pronated and ulnarly deviated position, is the mechanism most commonly described for a scaphoid fracture. In high-energy injuries, there is significant pain and swelling. In lower-energy injuries, however, the outward signs of trauma may be subtle. It is in these subtle injuries that early diagnosis is most critical. These are likely to be the nondisplaced injuries that may be managed nonoperatively if they are identified early. Delay in diagnosis can lead to fracture displacement and nonunion. Therefore, all patients with radial wrist pain, snuffbox tenderness, or scaphoid tubercle tenderness should be treated with immobilization until the scaphoid is definitively determined to be intact.

Anatomy

The scaphoid is a cashew nut–shaped bone that is thinnest in its central portion, with slightly more bulbous ends. It creates a linkage between the proximal and distal rows of the carpus, neutralizing forces of extension and flexion on the midcarpal joint. As a result, there are significant forces across the scaphoid from its articulation with the trapezium and trapezoid. After injury, these forces contribute to a higher rate of nonunion than other carpal bones.

The scaphoid is covered almost entirely in articular cartilage and, therefore, bathed in synovial fluid. This fluid potentially can wash out valuable hematoma after scaphoid fractures. The cartilage also limits the potential entry points for vascularity (Fig. 1 from Gelberman 1980 [Fig. 4]). The dorsal oblique ridge is a nonarticular portion of the scaphoid through which the vessel enters and supplies the proximal pole of the scaphoid. The volar vessel contributes the blood supply to the distal third of the scaphoid. This retrograde blood flow explains the particular difficulty in treating more proximal fractures, because these injuries disrupt the blood supply to the proximal pole.

Classification

The Herbert classification system is the most commonly used system in the literature ( Fig. 7 ). It divides fractures into stable (type A), unstable (type B), delayed union (type C), and established nonunion (type D). It is useful in that each of these types suggest both a different type of treatment and a different likelihood of success with these treatments.

Unfortunately, defining displacement with imaging studies of the scaphoid can be challenging. Plain radiographs may not detect all fracture displacement. Displacement may be identified more readily by CT imaging. Therefore, nondisplaced scaphoid fractures on radiography may miss displacement noted on CT scans and, therefore, may characterize fracture stability poorly. Gilley and colleagues showed that 26% to 34% of radiographically nondisplaced scaphoid fractures were displaced on CT scan imaging. Davis has shown no difference in union rate between displaced and nondisplaced fractures when assessed with plain radiographs. When these injuries are assessed using CT scans, however, there is greater predictability. In 59 patients, 42 of 43 (98%) nondisplaced fractures went on to union with casting, whereas 5 of 16 (31%) displaced fractures went on to nonunion with casting. Therefore, in radiographically nondisplaced fractures, CT scans along the axis of the scaphoid should be used to confirm that the fractures are truly nondisplaced. In those that are found to be nondisplaced on CT imaging, there is evidence to show a significantly higher rate of union than for displaced fractures and, therefore, displaced fractures are considered unstable and surgical treatment typically is offered.

Although there is consensus in the differences between treatment and outcomes of stable and unstable injuries, it is unclear that this determination of stability can be performed with imaging alone. Buijze and colleagues reported on a series of scaphoid fractures evaluated with arthroscopy and noted that in 58 patients, 38 were found unstable at the time of arthroscopic evaluation. Only 27 of the radiographs, however, showed displacement resulting, with 11 of the unstable fractures considered nondisplaced. So, although a fracture may be minimally displaced, it is not necessarily stable. This information brings into question determining stability of a fracture BASED on plain radiographs and the treatment recommendations that ensue.

Imaging

Initial imaging for all patients with radial-sided wrist pain should include posteroanterior and lateral radiographs as well as a dedicated scaphoid view. When these studies demonstrate a fracture, more advanced imaging typically is indicated. When the radiographs are negative, there are 2 ways for a clinician to proceed. In many cases, a period of immobilization, typically 10 days to 14 days, is followed by repeat radiographs. By this time, most scaphoid fractures have become more evident on radiographs, as the bone at the edges of the fracture resorbs, leading to greater radiographic lucency.

In many athletes, the period of immobilization is not ideal, because it interferes with their sport or training, and a more expedient diagnosis is desired. In these cases, advanced imaging (magnetic resonance imaging [MRI]/computed tomography [CT]) should be obtained to either diagnose a fracture or rule one out. Although CT imaging approaches the ability of MRI to accurately diagnose scaphoid fractures, MRI is nearly 100% sensitive and specific for occult scaphoid injury. Therefore, the author typically uses MRI as the advanced imaging of choice in patients with suspected scaphoid fractures. When the MRI is negative, it is likely that there is not a fracture and the athlete can play as tolerated. The athlete should be followed after playing to ensure that an undiagnosed injury does not manifest, for example, an occult scapholunate ligament injury.

Advanced imaging also is used for purposes other than diagnosis. As discussed previously, in fractures diagnosed with radiography, CT scans can make a more accurate assessment of displacement, they can better define the fracture morphology, and they can help to plan a surgical approach when needed. CT imaging also has been helpful in diagnosing avascular necrosis of the proximal pole of a scaphoid fracture. MRI is the more typical imaging study used to assess vascularity of the proximal pole, although many surgeons feel that the best way to diagnose vascularity is to intraoperatively assess the blood flow of the proximal pole.

Although proximal pole viability has long been considered an important factor for scaphoid healing, there are some data that healing can occur in the face of proximal pole ischemia. Rancy and colleagues looked at 35 nonunions (23 proximal pole nonunions) and identified avascularity using MRI (39.1%), intraoperative bleeding (84.8%), and intraoperative histopathologic analysis (54.5%). Despite the evidence of avascularity on MRI, intraoperative assessment, and histopathology, 94.3% of the fracture had healed by 12 weeks. The investigators concluded that vascularized bone grafting likely is not needed regardless of bone vascularity, provided that scaphoid anatomy is restored and stabilized with rigid internal fixation with nonvascularized grafts, as needed.

Treatment

The treatment of scaphoid fractures in athletes takes on a different tone than in the general population. There are several aspects of athletes’ avocations that direct treatment decisions. First, most athletes participate in seasonal activities. That is, the timing of their sport typically is limited to a portion of the year and treatment is modified based on the timing of the injury relative to that season. Injuries that occur toward the end of the season are managed differently from those that occur 1 to 2 months before the season. Secondly, many athletes’ windows for sport participation are limited to a reasonably short period of their overall life. For a recreational cyclist, who may ride for another 40 years, the loss of several months of cycling while wearing a cast may not lead to considering more invasive treatments. In contrast, a college football player may have only 1 season left to determine if football may lead to a professional career and may wish to consider a treatment that leads to playing sooner, even if it is associated with higher risks. Finally, there are athletes of all types, and the potential for young athletes to develop into professionals should be weighed against the risks of invasive treatment. A 12-year-old football player may be treated differently from a 12-year-old gymnast. The former typically is too young to have any serious prospects for scholarship or professional sports, whereas the latter may be approaching the peak of an athletic career. All these issues must be weighed against the risks and benefits of each treatment method in consideration.

Additionally, treating most athletes involves consideration of other associated stake-holders in an athlete’s career. In cases of young athletes, they are the athlete’s parents. In collegiate athletes, that group includes the parents and the college coaches. In professional athletes, there are frequently coaches, agents, and team leadership. Although the physician may need to communicate with many individuals about the treatment plans chosen, the needs of the patient always should remain the primary focus of the treating physician.

For all patients, the decision to proceed with operative management typically resolves around fracture stability. Those fractures that are deemed stable typically can be treated in a nonoperative fashion. Therefore, all fractures that are displaced or those that are of the proximal pole typically are treated surgically. It is less clear how to proceed with treatment in the minimally displaced waist fracture, where nonoperative treatment has been shown to lead to union in many cases.

Nonoperative Treatment

For stable fractures, nonoperative treatment can lead to a high rate of union and should be considered for nondisplaced scaphoid waist fractures. The time to union of scaphoid fractures treated with casting is affected by the fracture location. ^, Distal fractures heal rapidly, typically in approximately 6 weeks. Waist fractures heal more slowly, going on to union in 8 weeks to 12 weeks, on average. Proximal pole injuries can take 12 weeks to 24 weeks to heal with immobilization, which is difficult for almost any athlete to tolerate.

If nonoperative treatment is chosen, the type of cast or splint that is best is still unclear. Historically, long arm thumb spica casts have been used to provide the least motion at the wrist of the scaphoid. Comparative studies have not demonstrated a difference in union rates or outcomes with long arm cast immobilization; therefore, fewer physicians choose this method. ^, More recent studies have shown faster healing with the use of a short arm cast without thumb immobilization and equal final union rates ; Buijze et al looked at 62 patients with minimally displaced scaphoid fractures that were treated in short arm casts. They were randomized into 2 groups, those in a thumb spica cast compared with short arm casts with the thumb free. CT scans were performed after 10 weeks of casting. The percentage of the fracture line that had bridging bone across it was recorded and compared. There was a significantly higher percentage of healing (85% vs 70%) for the group without thumb immobilization. The overall union rate was 98%, with the only nonunion in a patient who did not tolerate casting and had surgical intervention.

Grewal and colleagues investigated the effectiveness and speed of union for nonoperative treatment of nondisplaced scaphoid fractures; 172 patients were treated in a short arm thumb spica cast, leading to a union rate of 99.4% (1 nonunion). In patients without diabetes or cysts, the time to union averaged 49 days, as diagnosed by CT scan. This is shorter than most prior studies had suggested for union after nonoperative treatment. The investigators suggested that use of CT scans to assess union may lead to a shorter period of immobilization.

Another series of studies published in 2013 examined fracture types that can be treated successfully with cast immobilization. Davis found that fractures determined to be nondisplaced on CT scans or MRI would reliably go on to heal in 4 to 8 weeks with casting. Radiographic determination of displacement was inadequate, however, to predict reliable healing. Patients had CT scans performed after 4 weeks of casting. Many nondisplaced fractures already had signs of healing and then were removed from their cast all but 1 went on to complete union.

The author typically recommends 4 weeks of below-elbow thumb spica cast immobilization followed by additional short arm removable immobilization for 2 weeks. A CT scan is obtained at 6 weeks for in-season athletes. If greater than 50% of the fracture demonstrates bridging bone, the patient is released to activities as tolerated. For out-of-season athletes, the CT scan is delayed until 8 weeks to increase the likelihood that 50% bridging bone has formed.

Operative Treatment

All fractures that have been determined to be unstable require surgical treatment. The operative treatment of scaphoid fractures typically involves screw fixation, although Kirschner (K)-wires and plates also are used at times. The screw can be placed antegrade (from a dorsal approach) or retrograde (from a volar approach). It can be placed in an open fashion or percutaneously or arthroscopically assisted. The difference in management is based on fracture location, fracture displacement, and surgeon preference and experience.

For displaced fractures, a reduction is required to restore normal anatomy. This typically is done most simply with open reduction. It also can be affected with percutaneously placed K-wires used as joy sticks. This percutaneous reduction can be assessed fluoroscopically and/or arthroscopically.

Once the reduction has been achieved, the screw is placed. Typically, a headless compression screw is used. More distal fractures are addressed more easily using a volar approach, whereas more proximal fractures are addressed dorsally. Percutaneous fixation is possible from either approach ( Fig. 8 ). Dorsally placed screws tend to be placed more centrally within the scaphoid, because the trapezium can lead to a slight obliquity to the path of the compression screw. ^, When the presence of the trapezium precludes appropriate screw positioning relative to the fracture, a transtrapezial approach has been shown effective without significant long-term problems at the scaphotrapeziotrapezoid (STT) joint.