M.C. Vinod Kumar Reddy et al / International Journal of Biomedical and Advance Research 2015; 6(01): 60-63. 60 IJBAR (2015) 6 (01) www.ssjournals.com International Journal of Biomedical and Advance Research ISSN: 2229-3809 (Online); 2455-0558 (Print) Journal DOI: 10.7439/ijbar CODEN: IJBABN Case Report Os Trigonum syndrome – A case report M.C. Vinod Kumar Reddy* Sri Devaraj Urs Medical College, Tamaka. Kolar, Karnataka, India *Correspondence Info: Dr. M.C. Vinod Kumar Reddy, Sri Devaraj Urs Medical College, Tamaka. Kolar, Karnataka, India E-mail: vinodreddy872@gmail.com Abstract The ostrigonum is a small bone present on the posterolateral aspect of the talus. It is formed from a separate ossification center which fails to unite with the talus itself. Incidence is about 3-15%. The diagnosis can be difficult to make as symptoms and physical exam findings mimic those that occur with problems related to an accessory soleus muscle, flexor hallucislongus, posteriortibialis, or peroneal tendons, arthritis involving the posterior tibiotalar or subtalar joints, or ostrigonum syndrome. Misdiagnosis of such injuries may result in inadequate management including immediate weight bearing and prolonged symptoms Keywords: ostrigonum, talus, ankle pain, diagnosis 1.Introduction The developing human skeleton has several ossification centers that, when fails to fuse with the main body of their corresponding bone, are commonly accepted as normal anatomical variations without definite clinical significance. The ostrigonum is a small bone present on the posterolateral aspect of the talus formed from a separate ossification center which fails to unite with the talus itself[1][2]. It appears between the ages of 8 and11 years as a secondary centre of ossification and usually fuses with the talus within one year of its appearance[3][4]. When the ossification centre remains separate from the talus it is referred to as the ostrigonum. When fusion does occur and a large posterolateral process forms, it is referred to as a ‘fused ostrigonum’, a ‘Stieda’s process’, or a ‘trigonal process’[5][6]. The incidence of the ostrigonum has been reported to be 3-15% [2][7][8] and it is more often bilateral than unilateral[3]. The ostrigonum syndrome is characterized by pain, and sometimes swelling, in the posterolateral aspect of the ankle. The two mechanisms of injury originally described by McDougal involve either micro trauma from repetitive hyperplantar flexion or an episode of acute forced hyperplantarflexion[9]. This syndrome is most often seen in runners, soccer players, ballet dancers, and football players. The diagnosis of ostrigonum syndrome can be suspected from the clinical examination findings but is confirmed by radiographs showing the ostrigonum and by magnetic resonance imaging (MRI), computed tomography, and bone scans used to identify other bony and soft-tissue involvement[10][11]. Initial treatment is conservative. It includes rest, use of ice and anti- inflammatory medications, cortisone injections, and physical therapy. When conservative care is unsuccessful, surgical excision of ostrigonumis recommended. 2.Case History A 33 year old businessman presented with left ankle pain of 7 months duration. The pain started suddenly while he was playing badminton. He was unable to walk or run the following day and also noticed swelling of left ankle for which he consulted a local doctor and was treated with analgesics and reduced activity for 2 weeks. After 2 week the pain had subsided and the patient returned to playing badminton, when he again noticed pain in the left ankle.