Background. Fractures of the metatarsal bones are the most frequent fracture of the foot. Up to 70% involve the fifth metatarsal bone, of which approximately eighty percent are located proximally. Low-intensity pulsed ultrasound (LIPUS) has been shown to be a useful adjunct in the treatment of delayed fractures and non unions. However, there is no study looking at the success rate of LIPUS in fifth metatarsal fracture delayed unions. Objectives. The aim of our study was to investigate the use of LIPUS treatment for delayed union of fifth metatarsal fractures. Study Design & Methods. A retrospective review of patients who were treated with LIPUS following a delayed union of fifth metatarsal fracture was conducted over a three-year period (2013 – 2015). Delayed union was defined as lack of clinical and radiological evidence of union, bony continuity or bone reaction at the fracture site if 3 months has elapsed from the initial injury. Results. There were thirty patients (9 males, 21 females) in our cohort. The average age was 39.3 years. Type 2 fractures made up 43% of our cohort. Twenty-seven (90%) patients went on to progress to union clinically and radiologically following LIPUS treatment. Smoking (p=0.014) and size of fracture gap (p=0.045) were predictive of non-union. Conclusions. This is the first study looking at the use of LIPUS in the treatment of delayed union of fifth metatarsal fractures. We report a success rate of 90%. There is a role in the use of LIPUS in delayed union of fifth metatarsal fractures and can serve as an adjunct prior to consideration of surgery

Fifth metatarsal fractures are common and the majority unite regardless of treatment. A sub-type of these fractures carries a risk of non-union and for this reason many centres follow up all 5. th. metatarsal fractures. In 2011, a standardised protocol was introduced to promote weight-bearing as pain allowed with a tubigrip or Velcro boot according to symptoms. No routine fracture clinic appointments were made from A&E but patients were provided with information and a help-line number to access care if required. Some patients still attended fracture clinics, but only after review of their notes/X-rays by an Orthopaedic Consultant, or after self-reported “failure to progress” using the special help-line number. Audit of a year prior to the introduction of the protocol and the year following it was performed. All x-rays taken at presentation in A&E were reviewed and classified independently (KBF/JM) for validation. During 2009/2010, 279 patients presented to A&E with a 5. th. metatarsal fracture and were referred to a fracture clinic. 106(38%) attended 1 appointment, 130(47%) attended 2 appointments and 31 (11%) attended 3 or more appointments – 491 appointments in total. 3% failed to attend the clinic. Operative fixation was performed in 3 patients (1.07%). In 2011/2012, of 339 A&E fractures, only 63 (19%) attended fracture clinic. 37 (11%) attended 1 appointment, 12 (4%) 2 and 9 (3%) 3 or more appointments – 96 appointments in total. Four patients (1.17%) required operative fixation. Our study did not demonstrate any added value for routine outpatient follow-up of 5. th. metatarsal fractures. Patients can be safely allowed to weight bear and discharged at the time of initial presentation in the A&E department if they are provided with appropriate information and access to a “help line” run by experienced fracture clinic staff. The result is a more efficient, patient-centred service