Background. Scaphoid fractures with displacement have a higher incidence of nonunion and unite in a humpback position that can cause pain and reduced movement, strength and function. The aim of this study is to review the evidence available and establish the risk of nonunion associated with management of displaced scaphoid fractures in a plaster cast. Methods. Electronic databases were searched using the MeSH (Medical Subject Headings) controlled vocabulary (scaphoid fractures, AND'd with explode displaced, or explode nonunion, or explode non-healing or explode cast immobilisation, or explode plaster, or explode surgery). As no randomised or controlled studies were identified, the search was limited to observational studies based on consecutive cases with displaced scaphoid fractures treated in a plaster cast. The criterion for displacement was limited to gap or step of more than 1mm. The ‘random effects’ calculation was used to allow for the possibility that the results from the separate studies differ more than would be expected by chance. Results. Of the 27 articles identified, seven studies were eligible for the meta-analysis with a total of 1401 scaphoids. 93% (1311 scaphoids) of these scaphoid fractures healed in a plaster cast. 207 (15%) of all scaphoid fractures showed displacement of at least 1mm (Gap/step) between fracture fragments. Nonunion was identified in 18% (37/207) of displaced scaphoid fractures treated in a plaster cast. The pooled odds ratio of fracture nonunion between the displaced and undisplaced groups was five times higher with fracture displacement (pooled odds ratio: 5.5, 95%CI: 2.5–12.3; p=0.00, I. 2. =54.6%). The pooled relative risk of fracture nonunion was 4.4 (95%CI: 2.3–8.7; p=0.00 I. 2. =54.3%). Conclusions. Displaced fractures of scaphoid have a four times higher risk of nonunion when treated in a plaster cast and the patients should be advised of this potential risk