Secondary infection of haematoma following closed acromioclavicular joint dislocation

An unusual case of a patient presenting with a large infected haematoma following a traumatic grade II acromioclavicular joint dislocation is reported. Diagnosis of this rare complication, of an otherwise common self-limiting injury, was delayed until 19 days postinjury despite several presentations during this time with worsening swelling and pain. The patient was found to have significant tissue destruction by the time washout was performed and required multiple procedures to treat the infection. This case highlights the need for a high index of suspicion for complications, even following common self-limiting injuries, when patients represent with symptoms that do not fit the usual natural history of the condition, particularly if they have risk factors for bleeding and infection.