Unhappy triad posterior translation of the tibia on the femur. The classic O'Donoghue triad is characterized by an injury to three knee structures (in order): The anterior cruciate ligament is one of the four crucial ligaments in the knee. It originates from the lateral condyle of the femur and goes to the intercondyloid eminence of the tibia. Its function is to provide stability in the knee and minimize stress across the knee joint. It also restrains excessive forward movement in the leg and limits rotational movements in the knee. Injury An anterior cruciate ligament injury results from excess tension on the ligament.
Tuberosity of the tibia Tuberosity of the tibia The tuberosity of the tibia or tibial tuberosity or tibial tubercle is a large oblong elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end. It gives attachment to the patellar ligament, which attaches to the patella from where the suprapatellar ligament forms the distal tendon of the quadriceps femoris muscles. The quadriceps muscles consist of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. These quadriceps muscles are innervated by the femoral nerve. The tibial tuberosity thus forms the terminal part