Tarsometatarsal (TMT) Surgery: Procedure, Recovery, and Long-Term Outlook

What is TMT Surgery?

Tarsometatarsal (TMT) surgery refers to surgical procedures performed on the tarsometatarsal joints of the foot, most commonly to address chronic pain, instability, or deformity resulting from conditions like arthritis, trauma, or congenital issues.

Understanding the TMT Joint

The tarsometatarsal (TMT) joints, also known as Lisfranc joints, are a group of five joints located in the midfoot, connecting the tarsal bones (cuneiforms and cuboid) to the bases of the five metatarsal bones. These joints play a crucial role in the biomechanics of the foot, contributing to its stability, flexibility, and ability to adapt to uneven surfaces. While they allow for limited motion, their primary function is to provide structural support and distribute weight during standing, walking, and running. Dysfunction or damage to these joints can significantly impair foot function and cause considerable pain.

Why is TMT Surgery Performed?

TMT surgery is typically considered when conservative treatments have failed to alleviate symptoms or when the joint pathology is severe enough to warrant surgical intervention. Common indications for TMT surgery include:

• Osteoarthritis: Degenerative joint disease, often post-traumatic, causing pain, stiffness, and loss of function. This is the most frequent reason for TMT fusion.
• Post-Traumatic Arthritis: Arthritis developing after an injury to the TMT complex, such as a Lisfranc fracture-dislocation.
• Deformity Correction: Addressing structural deformities like pes planus (flatfoot) or pes cavus (high arch) where TMT joint involvement contributes significantly to the malalignment and pain.
• Instability: Chronic instability of the TMT joints, sometimes following ligamentous injury, leading to pain and functional limitations.
• Charcot Arthropathy: A severe, progressive joint destructive process often seen in individuals with neuropathy (e.g., diabetes), leading to severe deformity and instability.

Prior to surgery, non-surgical options such as rest, anti-inflammatory medications, orthotics, bracing, physical therapy, and corticosteroid injections are usually attempted.

Types of TMT Surgery

The most common type of TMT surgery is arthrodesis, or joint fusion, which aims to permanently join two or more bones together across a joint. This eliminates motion at the joint, thereby alleviating pain caused by friction or instability.

• TMT Joint Arthrodesis (Fusion): This procedure involves removing the damaged cartilage from the joint surfaces and then fusing the bones together using screws, plates, or staples. The goal is to create a solid, stable bone mass where the joint once was. While it eliminates motion, the surrounding joints often compensate, allowing for relatively normal ambulation. It is particularly effective for severe arthritis or instability.
• Joint Preservation Procedures: Less common for TMT joints due to their limited natural motion and the effectiveness of fusion, but may include:
  • Debridement: Cleaning out the joint of damaged tissue.
  • Osteotomy: Cutting and reshaping bone to correct alignment or reduce pressure on the joint.
  • Cheilectomy: Removing bone spurs (osteophytes) that limit motion or cause pain.

The Surgical Procedure

TMT fusion surgery is typically performed under general anesthesia or regional anesthesia (e.g., a spinal block) with sedation. The general steps involve:

1. Incision: An incision is made over the top of the midfoot to expose the affected TMT joint(s). The specific location and number of incisions depend on which joints are being treated.
2. Joint Preparation: The surgeon carefully removes the damaged articular cartilage from the ends of the bones forming the joint. This creates raw, bleeding bone surfaces that are conducive to fusion.
3. Bone Grafting (Optional): In some cases, bone graft material (either from the patient, a donor, or synthetic) may be packed into the fusion site to promote healing and enhance the likelihood of a successful fusion.
4. Fixation: The bones are then held together in their corrected anatomical position using internal fixation devices such as screws, plates, or staples. This provides stability while the bones heal and fuse together.
5. Wound Closure: The incision is closed in layers, and a sterile dressing is applied. A cast, splint, or boot is typically applied to immobilize the foot.

The duration of the surgery can vary depending on the complexity and the number of joints being fused.

Recovery and Rehabilitation

Recovery from TMT surgery, particularly fusion, is a lengthy process that requires patience and adherence to post-operative protocols.

• Immobilization: The foot is typically immobilized in a non-weight-bearing cast or boot for 6-12 weeks to allow the bones to fuse. Crutches, a knee scooter, or a wheelchair will be necessary during this period.
• Weight-Bearing Progression: Gradual weight-bearing is usually initiated after radiographic evidence confirms initial bone healing, typically around 6-8 weeks post-op. This progression is carefully monitored by the surgeon.
• Physical Therapy: Once weight-bearing is allowed, physical therapy begins. Initially, it focuses on reducing swelling, improving range of motion in the ankle and unfused foot joints, and restoring balance. As healing progresses, exercises will advance to strengthening the muscles of the foot and ankle, improving gait mechanics, and gradually reintroducing functional activities.
• Return to Activity: Full recovery and return to most activities, including light exercise, can take 6-12 months. High-impact activities or sports may be limited long-term, depending on the extent of the fusion and individual outcomes. Swelling can persist for several months.

Potential Risks and Complications

As with any surgical procedure, TMT surgery carries potential risks, including:

• Infection: Risk of bacterial infection at the surgical site.
• Bleeding: Excessive bleeding during or after surgery.
• Nerve Damage: Injury to nerves in the foot, potentially leading to numbness, tingling, or weakness.
• Non-Union: Failure of the bones to fuse together, requiring further surgery. This is a significant risk with foot fusions.
• Malunion: Bones healing in an incorrect position, which may cause ongoing pain or altered biomechanics.
• Hardware Issues: Irritation or pain from the screws or plates, potentially requiring their removal in a second procedure.
• Deep Vein Thrombosis (DVT): Blood clots in the leg.
• Anesthesia Risks: Adverse reactions to anesthesia.
• Adjacent Joint Arthritis: Increased stress on neighboring joints due to the fused segment, potentially leading to future arthritis in those joints.

Long-Term Outlook and Activity Considerations

The long-term outlook following successful TMT fusion is generally good, with many patients experiencing significant pain relief and improved functional stability. While fusion eliminates motion at the treated joint, the foot often adapts well, and most individuals can resume daily activities, including walking, cycling, and swimming, without significant limitations.

However, activities involving pivoting, quick changes of direction, or high impact (e.g., running, jumping, court sports) may be more challenging or discouraged, depending on the extent of the fusion. Footwear choices may also need to be adjusted to accommodate any residual stiffness or changes in foot shape. Regular follow-up with a healthcare provider and adherence to a prescribed exercise program are crucial for optimizing long-term outcomes and maintaining foot health.