CMC Joint Surgery: Risks, Complications, and Recovery

What can go wrong with CMC surgery?

While CMC (carpometacarpal) joint surgery for thumb osteoarthritis is highly effective for many, like any surgical procedure, it carries inherent risks and potential complications that patients should be thoroughly aware of.

Understanding CMC Joint Surgery

The carpometacarpal (CMC) joint, located at the base of the thumb where the metacarpal bone meets the trapezium bone of the wrist, is crucial for the thumb's wide range of motion and its ability to pinch and grasp. Osteoarthritis, a degenerative joint disease, commonly affects this joint, leading to pain, stiffness, weakness, and functional limitations. When conservative treatments fail, surgical intervention becomes an option. The most common surgical procedure is a trapeziectomy, which involves removing the trapezium bone, often combined with some form of ligament reconstruction or interposition arthroplasty to stabilize the thumb and prevent metacarpal collapse into the void. Other less common procedures include joint fusion (arthrodesis) or joint replacement (arthroplasty).

General Surgical Risks

Regardless of the specific procedure, all surgeries carry a set of general risks that apply to CMC joint surgery:

• Infection: This can range from superficial skin infections to more serious deep-seated infections involving the joint or bone. Infections may require antibiotics or, in severe cases, further surgery.
• Bleeding: Post-operative bleeding can lead to hematoma formation, which may cause swelling, pain, and delay healing. Significant bleeding is rare.
• Anesthesia Risks: While modern anesthesia is generally safe, potential risks include allergic reactions, respiratory problems, nausea, and in very rare cases, more severe cardiovascular events.
• Pain: While the surgery aims to alleviate chronic arthritis pain, post-operative pain is expected and managed with medication. Persistent or chronic pain, unrelated to the initial arthritis, can sometimes occur.
• Scarring: Incisions will result in a scar. In some individuals, scars can become hypertrophic (raised and red) or keloid (excessively large and raised).

Specific Complications of CMC Joint Surgery

Beyond general surgical risks, CMC joint surgery has specific potential complications related to the anatomy and function of the hand:

• Nerve Injury:
  • Sensory Nerve Damage: The superficial radial nerve, which provides sensation to parts of the thumb and back of the hand, is in the surgical vicinity. Injury can lead to numbness, tingling, or an area of hypersensitivity (neuroma) in the distribution of the nerve. While often temporary, it can be persistent.
  • Motor Nerve Damage: Damage to motor nerves controlling thumb movement is less common but can occur with deep dissection, potentially leading to weakness in specific thumb muscles.
• Tendon Problems:
  • Tendonitis or Rupture: If a tendon is used for reconstruction (e.g., FCR tendon), there's a small risk of inflammation (tendonitis) or, rarely, rupture of the transferred tendon.
  • Tendon Adhesions: Scar tissue can form around tendons, limiting their smooth gliding motion and potentially leading to stiffness or reduced range of motion.
• Persistent Pain or Weakness:
  • Incomplete Pain Relief: While surgery often significantly reduces pain, some individuals may still experience residual pain, or the pain may not be entirely resolved.
  • Pillar Pain: This is a common complaint after trapeziectomy, characterized by pain at the base of the thumb on the radial (thumb) side, often related to the altered mechanics of the wrist and thumb. It usually improves with time and therapy but can persist.
  • Pinch/Grip Weakness: While the goal is to improve function, some patients may experience a degree of persistent weakness in pinch or grip strength, especially in the early post-operative period.
• Stiffness and Reduced Range of Motion: Scar tissue formation, inadequate rehabilitation, or prolonged immobilization can lead to stiffness in the thumb or wrist, limiting the overall range of motion.
• Instability or Subluxation: If the thumb metacarpal is not adequately stabilized after trapezium removal, it can shift or subluxate (partially dislocate) into the void, leading to instability and potential pain or functional issues. This is why ligament reconstruction or interposition is often performed.
• Complex Regional Pain Syndrome (CRPS): A rare but severe complication, CRPS is a chronic pain condition that can develop after injury or surgery. It's characterized by disproportionate pain, swelling, changes in skin temperature and color, and functional impairment in the affected limb. Early recognition and treatment are crucial.
• Non-Union or Mal-Union (for fusion procedures): If a fusion (arthrodesis) procedure is performed, there's a risk that the bones may not fuse together (non-union) or may fuse in an improper alignment (mal-union), requiring further intervention.
• Implant-Related Complications: If an implant (e.g., a spacer or prosthetic joint) is used, risks include implant loosening, wear, fracture, or allergic reaction to the implant material.

Factors Influencing Risk

Several factors can influence the likelihood and severity of complications:

• Patient Health Status: Underlying health conditions such as diabetes, smoking, poor circulation, or autoimmune disorders can increase the risk of infection, poor wound healing, and other complications.
• Surgeon's Experience: The skill and experience of the orthopedic surgeon can significantly impact surgical outcomes and the likelihood of complications.
• Adherence to Post-Operative Rehabilitation: Strict adherence to the prescribed physical or occupational therapy program is critical for optimal recovery and minimizing stiffness, weakness, and other complications.
• Type of Surgical Procedure: Different surgical techniques carry varying risk profiles.

Importance of Pre-Surgical Consultation and Post-Operative Care

Understanding the potential complications is not meant to deter individuals from necessary surgery but to empower them with knowledge. A thorough pre-surgical consultation with your orthopedic surgeon is paramount. During this discussion, your surgeon will assess your individual risk factors, explain the specific procedure recommended for you, and detail the potential benefits and risks.

Equally important is diligent adherence to your post-operative care and rehabilitation program. Physical and occupational therapy play a crucial role in restoring strength, mobility, and function, and in mitigating long-term complications. Early recognition and reporting of any unusual symptoms post-surgery are also vital for prompt management.

Conclusion

While CMC joint surgery offers significant relief and improved function for many suffering from advanced thumb base arthritis, it is a significant procedure with potential risks. By understanding these potential complications and actively participating in your pre- and post-operative care, you can work collaboratively with your healthcare team to optimize your outcomes and minimize adverse events.