Hypertrophic synovial plica in the lateral side of the knee - A case report: Case report and literature review

Introduction: Plicae or synovial folds can be detected in different joints, especially around the knee. Synovial plicae pathologies are rare conditions with difficulty in diagnosis because of various symptoms overlapping with other diseases. Presentation of case: We reported a rare case of symptomatic hypertrophic synovial plica in the lateral side of the knee in a 12-year-old boy following a traumatic event almost two years before the surgery. The diagnosis and treatment were conducted by knee arthroscopy, and follow-up of the patients showed significant improvements with no pain or range of motion restrictions. Discussion: The reported case had a significantly lower age of presentations compared to most previously reported cases, and he was diagnosed with lateral knee hypertrophic plicae, while medial knee hypertrophic plicae are more commonly reported, which is considered rare findings. Contrary to previous studies of lateral plica, our case had a history of significant direct trauma, and he was not a professional athlete. Furthermore, based on evidence, hypertrophic synovial plicae are mostly asymptomatic, but in our case, there was a pain in his knee that worsened in flexion. Conclusion: Physicians should consider the possibility of synovial hypertrophic plicae, especially in younger patients with histories of direct traumatic events.