Introduction. Hallux valgus is a common orthopaedic complaint with multiple surgical options. There are many methods available for assessing whether sufficient translation of the first metatarsal can be achieved with a metatarsal translational osteotomy alone. None of the current methods take into account the breadth of the metatarsal. With current PACS technology a radiograph can be zoomed to any size and we postulate that by using the surgeon's thumb (or any suitable digit), as a sizing tool, a safe clinical decision can be made concerning whether a translational metatarsal osteotomy alone will provide sufficient correction. Method. We reviewed the preoperative radiographs (weightbearing AP) of twenty patients who had scarf and akin osteotomies and twenty patients with a deformity too great for scarf and akin osteotomies. The senior author (CC) taught the rule of thumb to one consultant and two registrars (total two registrars and two consultants). The radiographs were blindly randomised and the participants assessed each radiograph and decided whether sufficient translation could be achieved with a translational metatarsal osteotomy alone. The process was repeated three months later. Twenty patients were deemed sufficient for intra-user variability and significance based on a recent JBJS(A) article concerning radiographic measurements post proximal crescentic osteotomy (Shima et al. 2009). Results. Good inter- and intra- user variability was demonstrated and using the rule of thumb is a safe way of determining whether a distal osteotomy alone will provide sufficient correction