Dysplasia epiphysealis hemimelica of the knee: an unusual presentation with intra-articular loose bodies and literature review

Dysplasia epiphysealis hemimelica (DEH) is a rare disease characterized by the formation of osteochondromas asymmetrically at the epiphysis of extremities, typically involving the ankle and the knee. It progresses during childhood and presents with limited range of motion, swelling, and angular deformities. A 9-year-old boy with a 7-year history of DEH and previous removal of ankle osteochondromas presented with acute knee pain, swelling, and limited range of motion. A clinical, radiographic, and literature review of this case was conducted to better describe this occurrence. On the basis of clinical and radiographic analyses, loose bodies were found to be originating from intra-articular osteochondromas. Because of the patient’s symptoms, an exploratory arthroscopy was performed to further assess the formations, and the loose bodies were removed. After the procedure, the patient’s function and symptoms improved. To the best of our knowledge, this is the first report of a case that identifies a complication of DEH to be loose bodies with a clear etiology and acute progression of symptoms. The possibility of loose bodies should be considered when examining a patient diagnosed with DEH with acute progression of symptoms. Level of evidence level IV, case report.