The ACL is one of the key stabilizers of the knee. Rupture of the ACL is more common in athletes and people who engage in heavy physical work. ACL ruptures occur due to the constant tension of the ligament in all movements because it prevents mutual movements of the joint bodies. Risk factors that can lead to rupture are: increased body weight, inadequate footwear, muscle fatigue, genetic predisposition and female gender. Injuries often occur due to direct contact with another player (in sports), a sudden change of direction or an improper landing. The forces acting on the joint are the strongest, and this is the main reason for the rupture, and it depends on the strength of the force whether the rupture will be total or partial. ACL rupture is divided into 3 stages: sprain, partial rupture and total rupture. The diagnosis is made on the basis of history, clinical examination, MR - and specific tests, of which the Lachman test and the anterior drawer test are applied. The aforementioned patient had an ACL rupture - which was not repaired immediately due to the cessation of professional sports. After removing the cyst, the patient was sent to physical therapy, after which his condition improved. After a certain time (6 months after surgery) when returning to activities, the injury recurred and a safe rupture of the ACL and a partial rupture of the medial meniscus were confirmed. After the operation, a detailed rehabilitation with the use of orthotics is planned. The rehabilitation itself is divided into 4 phases: early protective phase, middle phase, advanced phase and phase of return to activity. Through each phase, the patient's progress was monitored in detail through a manual muscle test, measurement of range of motion as well as muscle fatigue and feeling of tiredness.