Incidental Arthroscopic Finding of Rheumatoid Arthritis in a Post-traumatic Ligamentous Injury to Knee Joint.

Introduction: The relationship between physical trauma and subsequent symptoms of rheumatoid arthritis (RA) has been described in the past though onset of newer disease of RA in apparently normal patient is doubtful. Trauma can cause precipitation of RA symptoms. Such trauma includes fractures, joint injuries, road traffic accidents, and also surgeries and deliveries. Although post-traumatic osteoarthritis following anterior cruciate ligament (ACL) injury is more common pathology, association of RA following ACL injury has not been reported in the literature. This case report highlights on one rare incidental diagnosis of RA postoperatively in a patient with traumatic ACL tear with previously no features of RA and how patient was managed successfully both by surgical and by medical management. Case Report: A 30-year-old male patient presented to us with complaints of pain over right knee associated with recurrent swelling, instability, clicking sounds, and occasional locking episodes since 6 months following twisting injury with no other symptoms in other joints of the body. Based on clinicoradiological workup, the diagnosis of traumatic complete ACL tear with medial meniscus bucket handle tear of body and posterior horn with early osteoarthritic changes was made. The patient was operated with ACL reconstruction with quadrupled hamstring graft, partial medial meniscectomy and debridement + microfracture for cartilage defects. The patient was worked up for inflammatory arthritis post operatively considering unusual synovitis of knee. Based on histopathological and serological investigations (rheumatoid factor and anticitrullinated protein antibody), the patient was put on disease modifying antirheumatoid drugs for 1 year. At 1-year follow-up, the patient was back to his normal activities with full range of movements with Lysholm Knee Score of 89. Conclusion: Traumatic ACL tear can result in onset of RA following trauma and needs to be worked up further when there are findings of unusual synovitis or cartilage damage arthroscopically. Such association is rare and concomitant diagnosis of RA or other inflammatory arthritis can be easily missed out if not addressed properly.