Acute calcific deposition in the lateral collateral ligament of the knee.

We present a rare case of a patient presenting with acute onset knee pain, which was subsequently diagnosed and treated as acute calcific deposition in the lateral collateral ligament. A 51-year-old gentleman presented to the emergency department with acute onset, excruciating, and left knee pain. There was no preceding history of trauma or systemic upset. Examination revealed exquisite tenderness over the lateral aspect of the knee with leg edema and an associated knee effusion. Blood tests showed a raised C-reactive protein. Plain radiographs of the knee showed a poorly defined calcific deposition with a "cloud-like" configuration. Following exclusion of all more threatening causes of symptoms, the patient was diagnosed with acute calcific tendinitis. The patient's pain was unremitting despite intravenous opiates, and he was taken to the operation theater for exploration and removal of the irritant crystal deposition from the lateral fibular collateral ligament resulting in complete resolution of symptoms. Acute calcific deposition in the lateral collateral ligament is a rare condition. There have been very few reports of this in the literature to date, and no reported cases of surgical excision. Calcific deposition can be treated successfully using conservative measures with symptoms settling after 4 to 6 weeks, however operative excision has been shown to be appropriate in specific cases. Acute calcific deposition should be considered in patients with unexplained acute knee pain and swelling, following the exclusion of other more common conditions. We present the first operatively treated case with accompanying radiology images, intraoperative medical photography, and histological slides.