The rupture of the anterior cruciate ligament (ACL) is one of the most common causes of post-traumatic osteoarthritis oft he knee, with a relative risk of 3.84 times higher in the first ten years compared to the uninjured knee. The causes of post-traumatic osteoarthritis following an ACL rupture are multiple. The primary factor is rotational instability rather than anterior translational instability, partial meniscectomy, obesity, and factors related to rehabilitation, as well as post-traumatic and postoperative inflammation. There is strong evidence in the literature that ACL reconstruction reduces the rate of secondary meniscal and cartilage injuries in both children and adults. However, it seems that this surgery does not affect the progression of osteoarthritis at 10 years or more, according to the most recent systematic reviews. It remains to be demonstrated, through high-quality research, that the improved surgical techniques which show better postoperative stability, fewer re-ruptures, and maximum preservation of meniscal integrity, will result in a reduction of post-traumatic osteoarthritis.