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Tibial tubercle osteotomy (TTO) is most commonly performed for isolated patellar instability in the presence of knee pain.
It is a surgical procedure to improve alignment of the patella.
It is performed by changing the insertion point of the patellar tendon on the tibia.
Patellofemoral disorders are common in the general population and a frequent primary complaint on presentation.
The other pathologies addressed are patellofemoral osteoarthritis, patella alta, and patella baja with or without knee pain.
TTO significantly improves knee pain and clinical outcome scores, though 21% of patients require reoperation for hardware removal.
Patellofemoral pain and patellofemoral instability are common orthopedic problems: 30% of patients 13 to 19 years old have patellofemoral pain and that 29 in 100,000 patients 10 to 17 years old have patellofemoral instability.
TTO indications include patellofemoral maltracking or malalignment, patellar instability, patellofemoral arthritis, and focal patellofemoral chondral defects.
With TTO, the goal is to move the tibial tubercle in a direction that will either improve patellar tracking or offload the medial or lateral patellar facet to improve pain and function.
Patients with patellofemoral pain often report anterior knee pain, which typically begins gradually and is often activity related.
Patellofemoral symptoms may be present: pain with prolonged sitting with knees bent; pain on rising from a seated position; pain or crepitus with climbing stairs; and pain during repetitive activity such as running, squatting, or jumping.
Patellofemoral instability can be a dislocation or subluxation event.
Physical examination with assesses for limb alignment, ligamentous laxity, overall peri-knee muscle tone and strength, effusion, and gait pattern.
The patella and surrounding anatomy must be palpated for location and severity of tenderness, and patellar tilt, height, mobility, and dynamic tracking, including J-sign, are pertinent to evaluation.
Examination of the asymptomatic contralateral side is essential for comparison.
Plain radiographs are first-line imaging.
Computed tomography or magnetic resonance imaging can be used to measure tibial tubercle-trochlear groove (TT-TG) distance.
Tibial tubercle-trochlear groove distance of >15 mm is abnormal, and >20 mm indicates tibial tubercle osteotomy is required.
Essentially, the patella is translated to offload the affected areas.
Osteotomy and movement of the tibial tubercle can include anteriorization, anteromedialization, proximalization, medialization, or distalization.
The most common pathology treated with TTO is isolated patellofemoral instability at about 70%.
Majority of patients reporting good (37.9%) or excellent (39.2%) results.
Complication rates for this isolated-TTO patients were 1.2% for revision TTOs, 0.5% for wound complications, 0.8% for tibial tubercle fractures, and 1.9% for proximal tibia fractures.
TTOs improve patient pain and clinical outcome scores with having a high (16%) rate of reoperation for painful hardware in patients with preoperative pain or instability, or with patellofemoral osteoarthritis or ab2242ant patellar anatomy.
Less than 1% of patients require conversion to a patellofemoral arthroplasty or total knee arthroplasty