Skip to main content

Tibial Tubercle Osteotomy (TTO) for Patellar Instability / Maltracking


What is patellar instability or maltracking?

The patella (kneecap) is attached by tendons to the femur (thigh bone) and the tibia (shin bone). The patella fits into a grove at the end of the femur called the trochlear groove. When the knee bends or straightens, the patella slides up and down. Patellar instability occurs when the patella moves outside of the trochlear groove.  Patellar dislocations may occur from a traumatic injury, as a result of naturally loose ligaments, or due to individual variations in bony anatomy. People with these injuries are often described as having patellar instability.


Who is a candidate for a Tibial Tubercle Osteotomy (TTO)? 

A tibial tubercle osteotomy (TTO) is used to treat patients who suffer from patellar instability or painful patellar maltracking. By moving the bone (tibial tubercle), it can correct the malalignment of the patella, eliminate symptoms of instability, and decrease the symptoms of arthritis. TTO can also be performed in conjunction with MPFL reconstruction or cartilage repair surgery. Ideal candidates for TTO surgery include: 

  • History of multiple patellar dislocations
  • History of patellar and femoral pain
  • Physical therapy has been exhausted
  • Non-surgical management has failed


How is a TTO surgery performed? 

Tibial Tubercle Osteotomy (TTO) is a surgical procedure to improve alignment of the patella. This is performed by changing the insertion point of the patellar tendon on the tibia (tibial tubercle).

A 5-6 cm incision is made on the front part of the knee and the tibial tubercle is repositioned and held in place with two screws, in order for it to heal in this new location.