Background: In skeletally mature patients, anterior cruciate ligament (ACL) avulsion fractures are considered uncommon. The objective of this paper is to present a rare case of a bilateral tibial spine avulsion in a skeletally mature one-month post-partum woman and to review literature on tibial spine avulsion fractures in the adult population. Case Report: A 30-year-old healthy female one-month post-partum suffered a crushing injury of both knees. She was diagnosed with Meyer-McKeever type II fracture on the right and type IIIA fracture on the left. According to literature review, female gender and post-partum ligamentous laxity were possible risk factors for this rare injury. Ten days after injury the fractures were treated surgically. Three months post-operatively she was pain free with full range of movements and had no clinical signs of knee instability. X-rays demonstrated complete fracture union. Conclusion: The case presented concludes a rare diagnosis in a skeletally mature post-partum woman with high likelihood of pregnancy related osteoporosis and ligamentous laxity which probably were risk factors in the pathophysiology mechanism of injury.