Patients who have patellofemoral instability or patellofemoral arthritis that is localized to certain portions of the patellofemoral joint (kneecap), may be candidates for a tibial tubercle osteotomy. In this circumstance, the tibial tubercle is either elevated or moved distally (away from the center) and elevated to try to restore a more normal position of the patella, or to unload the patella from an area of arthritis on the trochlea or distal pole of the patella.
A thorough work-up is necessary to determine which patients may be candidates for a tibial tubercle osteotomy. In patients with patellar instability and patella alta, who also have a tibial tubercle-trochlear groove (TT-TG) distance of 2 cm or greater, a tibial tubercle osteotomy may be indicated. In addition, for patients who have an articular cartilage resurfacing procedure of the distal half of their patella, or the medial or lateral portions of the trochlear groove, may also be candidates for tibial tubercle osteotomy.
Description of a Tibial Tubercle Osteotomy
In a tibial tubercle osteotomy, the tibial tubercle and the patellar tendon are detached and moved to a pre-calculated new position on the anterior tibia. Usually, this involved moving the tibial tubercle distally or distally and medially. The moved tubercle is held in place by two screws and washers. Usually, patients have a secure fixation which allows for early knee motion of up to 90 degrees of knee flexion.
A thorough workup is necessary to determine the underlying pathology and determine where the tibial tubercle will need to be transferred.
With this procedure, patients need to be non-weight-bearing for 6 weeks and the osteotomy itself can take up to 4 months to heal before significant stress can be placed across the quadriceps mechanism in order to make sure that they do not go on to have a full fracture of their tibia. This complication is rare, a sudden fall or stress to the knee could put the area of the tibial tubercle osteotomy under significant stress, which could lead to a fracture. A Tibial tubercle osteotomy is generally considered a higher level/ salvage type procedure.