Tibial Tubercle Osteotomy (TTO): General, Procedure-Specific, and Long-Term Complications

What are the complications of TTO?

Tibial Tubercle Osteotomy (TTO) is a surgical procedure primarily performed to address patellar instability, patellofemoral pain, or maltracking by repositioning the attachment point of the patellar tendon; however, like all surgical interventions, it carries a range of potential complications, from general surgical risks to specific issues related to bone healing, hardware, and long-term joint health.

Understanding Tibial Tubercle Osteotomy (TTO)

Tibial Tubercle Osteotomy (TTO) involves surgically cutting and repositioning a segment of the tibia (shin bone) where the patellar tendon attaches. This segment, known as the tibial tubercle, is then reattached with screws in a more favorable position. The primary goals of TTO are to unload the patellofemoral joint, correct patellar maltracking, or stabilize the patella, often in cases of recurrent dislocations. While generally effective for well-selected patients, it is crucial for both patients and healthcare professionals to understand the potential complications associated with this procedure.

General Surgical Complications

As with any invasive surgery, TTO carries inherent risks common to all operative procedures. These are not specific to TTO but are important considerations.

• Infection: This can range from superficial wound infections to deep infections involving the bone (osteomyelitis) or joint (septic arthritis), requiring prolonged antibiotic treatment or further surgery.
• Bleeding: While typically controlled, excessive bleeding can occur during or after surgery, potentially requiring a blood transfusion or leading to hematoma formation.
• Anesthesia Risks: Adverse reactions to anesthesia can include nausea, vomiting, respiratory issues, or, in rare cases, more severe cardiovascular events.
• Blood Clots (Deep Vein Thrombosis - DVT): Formation of blood clots in the deep veins, typically of the leg, which can potentially dislodge and travel to the lungs (Pulmonary Embolism - PE), a life-threatening condition. Prophylactic measures like early mobilization, compression stockings, and anticoagulants are often employed.
• Nerve Damage: While specific nerve damage is discussed below, general nerve irritation or injury can occur during surgical dissection, leading to temporary or permanent numbness, tingling, or weakness.
• Scarring: All surgical incisions result in a scar. Some individuals may develop keloid or hypertrophic scars, which are raised and more prominent.

Procedure-Specific Complications of TTO

These complications are directly related to the unique anatomy and mechanics involved in a tibial tubercle osteotomy.

• Non-Union or Delayed Union: This occurs when the osteotomized bone segment fails to heal (non-union) or heals very slowly (delayed union). This can necessitate prolonged immobilization, revision surgery with bone grafting, or hardware removal. Factors like smoking, poor nutrition, and certain medical conditions can increase this risk.
• Malunion: The bone segment heals, but in an incorrect or suboptimal position. This can lead to persistent patellofemoral pain, altered biomechanics, or recurrence of instability, potentially requiring corrective surgery.
• Hardware Complications: Screws used to fix the tibial tubercle can loosen, break, or cause irritation to surrounding soft tissues (e.g., skin, tendons). This often necessitates hardware removal once the bone has healed, or sometimes earlier if symptoms are severe.
• Neurovascular Injury:
  • Saphenous Nerve Injury: The infrapatellar branch of the saphenous nerve is particularly vulnerable due to its proximity to the surgical site, potentially leading to numbness or dysesthesia (abnormal sensation) over the anterior knee and medial shin.
  • Peroneal Nerve Injury: Less common but possible, injury to the common peroneal nerve can lead to foot drop (difficulty lifting the front part of the foot).
  • Vascular Injury: While rare, damage to nearby blood vessels like the anterior tibial artery can occur.
• Patellar Height Alterations (Patella Alta/Baja):
  • Patella Alta: If the tubercle is moved too far proximally, it can elevate the patella excessively, potentially leading to patellofemoral pain or instability.
  • Patella Baja: Conversely, if the patella is excessively lowered, it can increase patellofemoral joint compression and accelerate cartilage wear.
• Recurrent Patellar Instability: Despite the surgery, some patients may still experience recurrent patellar dislocations or subluxations, indicating that the underlying cause was not fully addressed or new biomechanical issues arose.
• Persistent Patellofemoral Pain: Even with successful bone healing and improved alignment, some patients may continue to experience pain, often due to pre-existing cartilage damage, residual maltracking, or other contributing factors.

Rehabilitation-Related and Long-Term Complications

The post-operative period and long-term outcomes can also present challenges.

• Stiffness and Arthrofibrosis: Immobilization and pain after surgery can lead to joint stiffness (arthrofibrosis) if not aggressively managed with physical therapy. This can limit range of motion and functional recovery.
• Muscle Weakness and Atrophy: Disuse and pain post-surgery inevitably lead to quadriceps and hamstring weakness and atrophy, requiring dedicated rehabilitation to restore strength and function.
• Complex Regional Pain Syndrome (CRPS): A rare but severe complication characterized by chronic, debilitating pain, swelling, and changes in skin temperature and texture, disproportionate to the initial injury or surgery.
• Accelerated Patellofemoral Arthritis: While TTO aims to reduce stress on the patellofemoral joint, pre-existing cartilage damage or subtle alterations in joint mechanics can sometimes lead to accelerated progression of arthritis over time.
• Re-injury: Returning to high-impact activities too soon or insufficient rehabilitation can lead to re-injury of the knee or surrounding structures.

Conclusion

Tibial Tubercle Osteotomy is a powerful tool in orthopedic surgery for addressing complex patellofemoral issues. However, like all surgical procedures, it is not without risk. A thorough pre-operative assessment, meticulous surgical technique, and a diligent, comprehensive post-operative rehabilitation program are crucial for minimizing complications and optimizing patient outcomes. Patients considering TTO should engage in detailed discussions with their orthopedic surgeon to understand the potential benefits and risks specific to their case, ensuring informed decision-making.