M21.2: Flexion deformity

Flexion deformity, described under the ICD-10 code M21.2, is a medical condition that denotes an abnormal bending or flexion of a joint or body part. It is generally characterized by the inability to fully straighten or extend the joint or body part, limiting the normal range of motion. This condition most commonly affects the knees, fingers, wrists, and elbows. The causes of flexion deformity usually stem from muscle imbalance, fractures, joint dislocations, or diseases such as rheumatoid arthritis or osteoarthritis. The progression of a flexion deformity can potentially lead to increased discomfort and difficulty with daily activities, such as walking in the case of the knee. Symptoms can vary depending on the specific joint affected but usually include visible misalignment, restricted movement, pain, and possible muscular atrophy due to disuse.