Anne Eva J. Bulstra MD1,2, Job N. Doornberg MD PhD2,3, Myriam C. Obdeijn MD PhD4, and Geert A. Buijze MD PhD5 1 Department of Orthopaedic Surgery, Academic Medical Center and University of Amsterdam, Amsterdam, The Netherlands 2 Department of Orthopaedic Surgery, Flinders Medical Centre & Flinders University, Adelaide, Australia 3 Department of Orthopedic Surgery, Academic Medical Center, Amsterdam, The Netherlands 4 Department of Plastic Reconstructive and Hand Surgery, Academic Medical Centre, Amsterdam, The Netherlands 5 Département de chirugie orthopédique et traumatologie, Montpellier, Montpellier, France Figure 151.1 Coronal CT image of the wrist displaying a nonacute fracture of the scaphoid waist extending to the distal pole, with a wide fracture cleft and sclerosis of the fracture surface, confirming scaphoid nonunion. Figure 151.2 Resolution of clinical scenario: scaphoid reconstruction with a corticocancellous bone graft. (A) Preoperative sagittal CT image of the wrist shows a tendency toward a humpback deformity. (B) The patient is treated with a nonvascularized corticocancellous graft of the distal radius. The postoperative CT, three months after surgery, demonstrates improvement in scaphoid height and near complete consolidation. Identification of risk factors associated with scaphoid nonunion contributes to the prevention, diagnosis, and tailored treatment in at risk patients. Although the majority of scaphoid fractures heal when treated conservatively, nonunion rates of up to 34% are reported in the literature.1,2 The relatively high rates of nonunion can be attributed to the scaphoid’s tenuous vascular supply and the poor diagnostic reliability of radiographs to diagnose acute scaphoid fractures. Identifying risk factors for nonunion may optimize treatment strategies. Assuming that surgical intervention increases rates of union in specific cases, these patients may be offered early surgical intervention. Fracture location and displacement are considered important determinants for fracture union. Proximal pole fractures are at the highest risk for nonunion (10–34%)1,7 compared to waist (0–33%)8,9 and distal (0–2%)10 pole fractures. The increased risk of nonunion in proximal pole fractures is typically attributed to the decreased arterial blood supply and associated risk of avascular necrosis (AVN).1 In displaced fractures, generally defined as fractures with a gap of 1 mm or greater between fragments, nonunion rates of up to 55% have been reported.11 CT is the recommended diagnostic test to identify fracture displacement and bony configuration of scaphoid fractures.4 An exponential relationship exists between the amount of fracture diastasis on CT and the risk of nonunion.4 Delayed treatment, resulting from both patient delay and missed diagnosis, increases the risk of nonunion. Nonunion rates are higher in fractures diagnosed and immobilized after four weeks (40%) compared to those treated within four weeks (3%).12 In a quantitative meta‐analysis of 1827 patients with established scaphoid nonunion, Merrell et al. described union rates of 90 versus 80% when fractures were treated surgically within, or after, 12 months, respectively (p <0.0001).2 A large inception cohort study by Zura et al. including 7149 scaphoid fractures, identified several risk factors for nonunion, including male sex, use of nonsteroidal anti‐inflammatory drugs (NSAIDs) or opioids, and osteoarthritis.3 Other studies reported higher success rates in nonsmokers undergoing corrective nonunion surgery than smokers.5,6 The aim of treating scaphoid nonunion includes union, the relief of symptoms, as well as the limitation of degenerative wrist arthritis, known as the SNAC wrist.13 Persistence of unstable scaphoid nonunion leads to degenerative changes in the scaphoid, radial styloid, and ultimately pancarpal arthritis of the scaphocapitate and capitolunate joints.13 A 97% incidence rate of degenerative changes in untreated symptomatic nonunions older than five years has been described.14 However, the actual correlation between symptoms and disease is poorly reported. It is not clear whether surgery significantly alters disease progression, even if union is attained.15 The prevailing treatment of scaphoid nonunion constitutes the use of a bone graft and internal fixation.25
151 Scaphoid Nonunions
Clinical scenario
Top three questions
Question 1: In patients with a scaphoid fracture, which risk factors are associated with scaphoid nonunion?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Resolution of clinical scenario
Question 2: In patients with a scaphoid nonunion, which management options, compared to others, yield the best outcomes?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Operative treatment
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
