Introduction: A case of neglected anterior dislocation of the knee leading to instablity with severe secondary osteoarthritis is very rare to come across, and there are not many reported articles to the best of our knowledge. Due to the rarity of the occurrence, there are no proper treatment guidelines laid out yet. Case Report: A 62-year-old hypertensive male with BMI 26.6 presents with an unstable lax right knee with severe osteoarthritis secondary to untreated chronic traumatic anterior dislocation of the knee that happened 12 years back. He was examined clinically and radiologically and further underwent total knee arthroplasty (TKA) for the same at our center. Discussion: Knee dislocation is a very rare injury and a case of neglected dislocation leading to unstable osteoarthritic knee is even more rare. These cases need thorough planning which should include an extensive clinical examination followed by imaging studies and Doppler scan to study the status of the vasculature. TKA for such a case is challenging and the use of hinged prosthesis or a constrained prosthesis is recommended when unstable. Keywords: Total knee arthroplasty, unstable knee, neglected knee dislocation.