CHAPTER 27 Acute Scaphoid Fractures in Nonunions
The scaphoid is the most frequently fractured bone in the carpus and accounts for approximately 70% of all carpal fractures.1 This fracture typically occurs in young men between the ages of 15 and 30 years.2 A scaphoid fracture is a common athletic injury, occurring most often in contact sports, particularly in football and basketball players. It is estimated that 1 of 100 college football players will sustain a fracture of the scaphoid.3 Commonly, an injured athlete continues to compete and eventually presents to the treating physician after the season is over with a scaphoid nonunion.
Acute nondisplaced fractures of the scaphoid have traditionally been managed with cast immobilization.4,5 Nondisplaced scaphoid fractures usually heal in 8 to 12 weeks when immobilized in long arm or short arm spica casts.4–6 Although cast immobilization is successful in up to 85% to 90% of cases, it must be asked what the cost is to the patient, particularly the athlete, who may not be able to tolerate a lengthy course of immobilization during the season or while actively training.4–6 Prolonged immobilization may lead to muscle atrophy, disuse osteopenia, joint contracture, and financial hardship. Until the fracture unites, the athlete may be inactive for 6 months or longer.
The duration of cast immobilization varies dramatically according to the fracture site. A fracture of the scaphoid tubercle may be healed within a period of 6 weeks, whereas a fracture of the waist of the scaphoid may require immobilization for 3 months or longer. A fracture of the proximal third of the scaphoid may take 5 months or longer to heal with a cast because of the vascularity of the scaphoid.7 This may result in loss of an athletic scholarship or loss of employment.
Displaced scaphoids have a reported nonunion rate of up to 50%.2 Factors that decrease the prognosis for healing include the amount of displacement, associated carpal ligament instability, and delayed presentation (>4 to 6 weeks).1 Traditionally, acute displaced fractures of the scaphoid and scaphoid nonunions have been managed by open reduction and internal fixation.1,2,8–16 Complications associated with open reduction fixation include avascular necrosis, carpal instability, donor site pain, infection, screw protrusion, and reflex sympathetic dystrophy resulting from the significant soft tissue dissection that is required.4,17 The most commonly reported complication in one series was hypertrophic scarring.2 Although jigs have been designed to assist an open reduction, they frequently are difficult to apply and may necessitate further extensive surgical dissection.18
Wrist arthroscopy has revolutionized the practice of orthopedics by allowing the surgeon to examine and treat intra-articular abnormalities of the wrist joint under bright light and magnification.19 The scaphoid is well visualized from the radiocarpal and midcarpal spaces. Whipple is credited with being the first surgeon to attempt arthroscopic management of scaphoid fractures.19 His preliminary work set the stage for the current concepts and treatment by arthroscopy of these common fractures.
The indications and techniques of arthroscopic management of acute scaphoid fractures and selected nonunions are reviewed in this chapter. Arthroscopic stabilization provides direct visualization of the fracture reduction, screw insertion, and limited surgical dissection, which may allow for a greater range of motion and earlier return to competition or employment.
TREATMENT
Indications
Arthroscopic stabilization of selected scaphoid nonunions may be performed. Slade and Geissler published their radiographic classification of scaphoid nonunions (Table 27-1).20
Type | Description |
---|---|
I | Delayed presentation at 4-12 wk |
II | Fibrous union, minimal fracture line |
III | Minimal sclerosis < 1 mm |
IV | Cystic formation, 1-5 mm |
V | Humpback deformity with > 5-mm cystic change |
VI | Wrist arthrosis |
Arthroscopic Techniques
Various arthroscopically assisted and percutaneous techniques for fractures of the scaphoid have been described in the literature.21–32 Haddad and Goddard24 popularized the volar approach, and the dorsal approach was popularized by Slade and colleagues.26 Geissler and Slade described a technique in which the starting point of the guidewire and the eventual screw insertion are determined arthroscopically, which limits guesswork concerning the insertion point.32
Volar Percutaneous Approach
In the volar percutaneous technique that was popularized by Haddad and Goddard, the patient is placed supine with the thumb suspended in a Chinese finger trap.24 Placing the thumb under suspension allows ulnar deviation of the wrist, which improves access to the distal pole of the scaphoid. Under fluoroscopic guidance, a longitudinal, 0.5-cm skin incision is made over the most distal radial aspect of the scaphoid. Blunt dissection is used to expose the distal pole of the scaphoid. The cutaneous nerves must be protected when using this technique.
A percutaneous guidewire is introduced into the scaphoid trapezial joint and advanced proximally and dorsally across the fracture site. The position of the guidewire is easily checked in the anteroposterior, oblique, and lateral planes by rotating the forearm under fluoroscopy. This provides an almost 360-degree view of the position of the guidewire within the scaphoid. The length of the guidewire within the scaphoid is determined by placing a second guidewire next to the initial one and measuring the difference between the two. A drill is inserted through the soft tissue protector, and the scaphoid is reamed. A headless cannulated screw is then placed over the guidewire. A second guidewire may be useful to prevent rotation of the fracture fragments while the screw is being inserted.
Haddad and Goddard reported their initial results in a pilot study of 15 patients with acute fractures of the scaphoid.24 Union was achieved in all patients within an average of 57 days (range, 38 to 71 days). With this percutaneous technique, the range of motion after union was equal to that of the contralateral limb, and grip strength averaged 90% at 3 months. The patients were able to return to sedentary work within 4 days and to manual work within 5 weeks.