Fulkerson Surgery: Understanding the Procedure, Recovery, and Risks

What is Fulkerson Surgery?

Fulkerson surgery, formally known as an anteromedial tibial tubercle osteotomy (AMTT), is a surgical procedure designed to stabilize the kneecap (patella) by repositioning its attachment point on the shin bone (tibia), thereby correcting patellar maltracking and reducing chronic instability.

Understanding Patellofemoral Instability

The patellofemoral joint, where the kneecap glides within the groove of the thigh bone (femur), is crucial for efficient knee function. For many individuals, recurrent kneecap dislocations or chronic instability stem from anatomical misalignments that cause the patella to track improperly, often pulling too far to the outside (lateral side) of the knee. This maltracking can lead to pain, swelling, a feeling of the knee "giving way," and damage to the articular cartilage beneath the kneecap. Conservative treatments, including physical therapy, bracing, and activity modification, are typically the first line of defense. However, for those with significant anatomical predispositions and persistent symptoms despite non-operative management, surgical intervention may be necessary.

What is Fulkerson Surgery?

Fulkerson surgery is a specific type of tibial tubercle osteotomy, named after orthopedic surgeon Dr. John P. Fulkerson, who popularized its use for chronic patellofemoral instability. The procedure involves carefully cutting a segment of bone from the front of the tibia, specifically the tibial tubercle, which is the bony prominence where the patellar tendon attaches. This segment, along with the attached patellar tendon and kneecap, is then shifted.

The key aspects of the Fulkerson osteotomy are:

• Medialization: The tubercle is moved inward (medially) towards the center of the knee. This helps to realign the patella within the trochlear groove, reducing the lateral pull that often causes instability.
• Anteriorization: The tubercle may also be moved forward (anteriorly) slightly. This can help to decrease pressure on the patellofemoral joint, particularly in cases where there is significant cartilage damage or a condition known as patella alta (a high-riding kneecap).

By repositioning the tibial tubercle, the surgery effectively changes the angle of pull of the quadriceps muscle on the patella, promoting more stable and centralized tracking of the kneecap during knee flexion and extension.

Who is a Candidate for Fulkerson Surgery?

Fulkerson surgery is generally reserved for individuals who meet specific criteria, highlighting its role as a targeted intervention for complex patellofemoral issues:

• Chronic Patellofemoral Instability: Patients must have recurrent patellar dislocations or significant, persistent symptoms of instability despite adequate conservative management.
• Specific Anatomical Abnormalities: Imaging studies (X-rays, MRI, CT scans) typically reveal underlying anatomical issues contributing to instability. These often include:
  • Increased Tibial Tubercle-Trochlear Groove (TT-TG) Distance: A measurement indicating excessive lateralization of the tibial tubercle relative to the trochlear groove.
  • Patella Alta: A kneecap that sits too high in the trochlear groove.
  • Trochlear Dysplasia: An abnormally shallow or flat trochlear groove, which provides less bony constraint for the patella.
  • Excessive Q-angle: A larger angle formed by the quadriceps tendon, patella, and patellar tendon, indicating a strong lateral pull on the kneecap.
• Failed Conservative Treatment: The patient must have undergone a comprehensive course of non-surgical treatment (e.g., physical therapy focusing on quadriceps strengthening, gluteal activation, core stability, and proprioception) without significant improvement in symptoms.
• Skeletally Mature: The procedure is typically performed on individuals whose growth plates have closed, as altering bone growth in still-growing individuals can lead to complications.

The Surgical Procedure

Fulkerson surgery is performed under general anesthesia, often with a regional nerve block for post-operative pain control.

1. Incision: An incision is made on the front of the knee, usually along the medial aspect of the tibia, to expose the tibial tubercle.
2. Osteotomy: Using specialized surgical saws, the orthopedic surgeon carefully cuts a block of bone containing the tibial tubercle. The cut is typically angled to allow for the desired medial and anterior shift.
3. Repositioning: The bony block is then carefully moved to its new, corrected position—medially and, if indicated, anteriorly.
4. Fixation: Once the optimal position is achieved, the bone block is secured to the rest of the tibia using two or more screws. These screws ensure the bone segment heals in its new alignment.
5. Adjunct Procedures: In many cases, Fulkerson surgery is combined with other procedures to address all aspects of patellar instability. A common co-procedure is a Medial Patellofemoral Ligament (MPFL) reconstruction, which involves reconstructing the primary ligament that prevents lateral patellar dislocation. Other procedures might include lateral retinacular release (cutting tight lateral tissues) or trochleoplasty (deepening the trochlear groove).
6. Closure: The incision is closed in layers, and a sterile dressing is applied.

Recovery and Rehabilitation

Rehabilitation after Fulkerson surgery is a critical component of a successful outcome and is typically prolonged, requiring significant patient commitment.

• Immediate Post-Operative Period (Weeks 0-6):
  • Pain Management: Medications are prescribed to manage pain and swelling.
  • Bracing: A knee brace is usually worn, initially locked in extension, to protect the healing bone and limit early range of motion.
  • Weight-Bearing Restrictions: Partial or non-weight-bearing with crutches is common for several weeks to allow the osteotomy site to begin healing.
  • Early Motion: Gentle, controlled range-of-motion exercises are initiated, often within a limited arc, to prevent stiffness and promote circulation.
• Intermediate Phase (Weeks 6-12+):
  • Gradual Increase in ROM: The brace may be unlocked, and the range of motion gradually increased as tolerated.
  • Strengthening: Progressive strengthening exercises are introduced, focusing on quadriceps (especially vastus medialis obliquus), hamstrings, glutes, and core muscles, initially with isometric exercises and then progressing to isotonic.
  • Gait Training: Progression from crutches to full weight-bearing.
• Advanced Phase (Months 3-6+):
  • Proprioception and Balance: Exercises to improve balance and joint awareness are emphasized.
  • Functional Training: Introduction of more complex movements relevant to daily activities and eventual return to sport.
  • Low-Impact Activities: Cycling, swimming, and elliptical training are often incorporated.
• Return to Sport/Activity (Months 6-12+):
  • Sport-specific drills, agility training, and plyometrics are gradually introduced under the guidance of a physical therapist.
  • Full return to unrestricted activity or sport typically takes 6 to 12 months, depending on the individual's progress, the demands of their activity, and the surgeon's clearance.

Potential Risks and Complications

Like any surgical procedure, Fulkerson surgery carries potential risks, though serious complications are rare:

• General Surgical Risks: Infection, excessive bleeding, blood clots (deep vein thrombosis), adverse reactions to anesthesia, and nerve or blood vessel damage.
• Specific Complications:
  • Non-union or Malunion: The osteotomy site may fail to heal properly (non-union) or heal in an incorrect position (malunion).
  • Hardware Irritation: The screws used for fixation can sometimes cause irritation, requiring removal in a subsequent procedure.
  • Persistent Pain or Stiffness: Despite successful surgery, some individuals may experience ongoing pain or limited range of motion.
  • Re-dislocation: While the goal is to prevent dislocation, a rare chance of re-dislocation exists, especially if combined with other predisposing factors.
  • Fracture: A stress fracture can occur at the osteotomy site.
  • Overcorrection: Though rare, excessive medialization can lead to medial patellar instability.

Expected Outcomes and Long-Term Outlook

Fulkerson surgery has a high success rate in stabilizing the patella and reducing episodes of dislocation for appropriately selected patients.

• Improved Stability: The primary goal is achieved in the majority of cases, significantly reducing or eliminating patellar dislocations.
• Pain Reduction: Many patients experience a substantial decrease in patellofemoral pain.
• Return to Activity: A significant percentage of individuals are able to return to their desired level of activity, including sports, although high-impact activities may need to be approached cautiously.
• Long-Term Outlook: While the surgery aims to improve patellar tracking and reduce pain, it does not guarantee the prevention of future osteoarthritis, especially if significant cartilage damage was present pre-operatively. Adherence to the rehabilitation program is paramount for optimizing outcomes and minimizing the risk of complications. Regular follow-up with the orthopedic surgeon is also important to monitor progress and address any long-term concerns.