Locked knee due to fat pad adhesion

BACKGROUND: A "locked" knee is defined as a knee that does not move freely after an injury. Most cases of locked knee are due to intra-articular blockade caused by an unstable meniscal tear, anterior cruciate ligament (ACL) tear, or chondral lesion resulting in a loose limb. In this study, we present a rare case of a locked knee caused by fat pad adhesion CASE PRESENTATION: A 23-year-old male presented with a locked right knee, after sustaining an injury falling one month before. Magnetic Resonance Imaging showed loss of ACL feature, normal posterior cruciate ligament, and meniscal tear of posterior horn. Arthroscopy procedure found fat pad adhesion, immobilizing the knee’s rotation. After removing all of the fat pad adhesion, the patient’s knee could move freely. CONCLUSION: Clinical and radiographic examinations are important for early diagnosis of the cause of locked knee, but arthroscopic examination is the gold standard for diagnosis.