Ankle osteomyelitis: an unusual presentation
A 52-year-old gentleman suffered an inversion injury to his left ankle following a tackle sustained during a football match. Over the next 48 h there was gradually increasing pain and swelling, resulting in difficulty in weight-bearing. Initial assessment in his local Emergency Department, including ankle radiographs, showed no evidence of bony injury. Ligamentous injury was suspected and he was managed conservatively.\nOver the next week his symptoms progressed and within that period he was unable to mobilize without crutches. He was admitted to hospital at this stage. A magnetic resonance imaging (MRI) scan was carried out of his ankle which showed a grade 1 injury to his medial collateral ligament, lateral ligament complex, tenosynovitis of the posterior tibial tendon, subtalar osteoarthritis, as well as some overlying soft tissue oedema. There was no evidence of bony injury, destruction or any infective processes. The patient was subsequently discharged with analgesics and referred for a course of physiotherapy.\nA bone scan was later performed which showed a florid increase in activity of the left ankle, highly abnormal and suspicious of infection (Figure). A white cell scan was also strongly positive for infection in the hindfoot. A subsequent computed tomography (CT) scan confirmed X-ray appearances of cortical destruction and lytic lesions in the calcaneus, talus, navicular and cuboid bones (Figure). These appearances were suggestive of osteomyelitis.\nSurgical debridement of his left hindfoot was performed and he was commenced on broadspectrum antibiotics (cefuroxime). As his pain was progressive, one week later he underwent a triple fusion of the ankle with exploration and washout. A below knee plaster of paris was fitted and was managed non-weight bearing. The inserted screws were planned to be removed after four months depending on whether union had been achieved. No culture was grown from the bone directly. Synovial soft tissue samples grew Staphyloccus aureus and he was subsequently placed on oral antibiotics according to hospital's microbiology protocol (trimethorpim and rifampicin due to his penicillin allergy).\nA follow-up CT three months postoperatively confirmed fusion in the subtalar and calcaneo-cuboid joint, with some incomplete fusion in the inferior aspect of the talonavicular joint.\nThe patient experienced no systemic symptoms in keeping with his infection right up until his discharge six months from the onset of his symptoms.