Proximal Row Carpectomy: Procedure, Benefits, Risks, and Recovery

What is a Proximal Row Carpectomy?

A proximal row carpectomy (PRC) is a surgical procedure that involves the removal of three bones from the proximal (near) row of the wrist: the scaphoid, lunate, and triquetrum. This intervention aims to alleviate pain and preserve a functional range of motion in the wrist, primarily for conditions affecting the carpal bones.

Understanding Wrist Anatomy

To fully grasp the concept of a proximal row carpectomy, it's essential to understand the intricate anatomy of the wrist. The wrist, or carpus, is composed of eight small carpal bones arranged into two rows:

• Proximal Row: These four bones articulate with the radius (forearm bone) and are, from radial (thumb) to ulnar (pinky) side:
  • Scaphoid: A boat-shaped bone, crucial for wrist stability and motion.
  • Lunate: A crescent-shaped bone, centrally located.
  • Triquetrum: A pyramidal bone, articulating with the ulna via the triangular fibrocartilage complex (TFCC).
  • Pisiform: A small, pea-shaped bone sitting on the palmar surface of the triquetrum, often considered part of the proximal row but not typically removed in a PRC.
• Distal Row: These four bones articulate with the metacarpals of the hand: trapezium, trapezoid, capitate, and hamate.

The smooth articulation between these bones, cushioned by cartilage, allows for the complex movements of the wrist.

What is a Proximal Row Carpectomy (PRC)?

A proximal row carpectomy is a specific surgical technique designed to address degenerative conditions within the wrist joint. The procedure involves the precise excision of the scaphoid, lunate, and triquetrum bones. By removing these damaged bones, the surgeon creates a new articulation between the head of the capitate (from the distal carpal row) and the lunate fossa of the radius (the concave surface at the end of the forearm bone).

The primary purpose of a PRC is to:

• Alleviate pain: By removing the source of the painful bone-on-bone grinding.
• Preserve functional motion: Unlike a complete wrist fusion, which eliminates motion, a PRC aims to maintain a useful range of flexion, extension, and deviation.
• Improve grip strength: Reduced pain and improved motion often lead to better functional grip.

Indications for a PRC

A proximal row carpectomy is typically considered for patients experiencing chronic wrist pain and functional limitations due to specific types of degenerative arthritis or avascular necrosis. Common indications include:

• Scapholunate Advanced Collapse (SLAC) Wrist: This is the most common indication. It results from chronic instability and degeneration of the scapholunate ligament, leading to abnormal motion and arthritis between the scaphoid, lunate, capitate, and radius.
• Scaphoid Non-Union Advanced Collapse (SNAC) Wrist: Occurs when a scaphoid fracture fails to heal (non-union), leading to collapse and subsequent arthritis.
• Kienböck's Disease: Avascular necrosis (death of bone tissue due to lack of blood supply) of the lunate bone. A PRC may be considered in advanced stages when other treatments have failed.
• Post-traumatic Arthritis: Arthritis resulting from severe wrist trauma that has damaged the carpal bones and articular cartilage.
• Rheumatoid Arthritis: In select cases where the disease primarily affects the proximal carpal row and other treatments are insufficient.

PRC is often chosen over total wrist fusion when preserving some wrist motion is a priority, and the articular cartilage of the capitate and the lunate fossa of the radius are relatively healthy.

The Surgical Procedure

A proximal row carpectomy is typically performed under regional or general anesthesia. The surgeon makes an incision on the back of the wrist to access the carpal bones. Using specialized instruments, the scaphoid, lunate, and triquetrum bones are carefully identified and removed. Once the bones are excised, the surgeon ensures a smooth articulation between the capitate and the radial lunate fossa. The wound is then irrigated, and the incision is closed with sutures. A splint or cast is usually applied post-operatively to immobilize the wrist.

Benefits of a PRC

Patients undergoing a successful proximal row carpectomy often experience significant benefits, including:

• Substantial Pain Relief: This is the primary goal and most consistently achieved benefit.
• Preservation of Functional Motion: While not a full range of motion, patients typically retain 50-70% of their pre-injury motion, which is crucial for daily activities.
• Improved Grip Strength: Reduced pain allows for greater force generation during gripping.
• Relatively Shorter Recovery than Fusion: While still significant, the recovery period can be less extensive than a total wrist fusion.

Potential Risks and Complications

As with any surgical procedure, a PRC carries potential risks, though serious complications are rare. These include:

• Infection: Risk of bacterial infection at the surgical site.
• Nerve Damage: Potential injury to nerves, leading to numbness or weakness.
• Stiffness: While aiming to preserve motion, some degree of stiffness is common.
• Persistent Pain: Though rare, some patients may not achieve complete pain relief.
• Progression of Arthritis: Over time, the newly formed articulation between the capitate and radius can develop arthritis, potentially requiring further intervention.
• Complex Regional Pain Syndrome (CRPS): A rare but severe chronic pain condition.

Recovery and Rehabilitation

Recovery from a proximal row carpectomy involves several phases and requires commitment to a structured rehabilitation program:

• Immobilization (4-6 weeks): Immediately after surgery, the wrist is typically immobilized in a cast or splint to protect the healing tissues.
• Early Motion (Post-immobilization): Once the cast is removed, physical therapy begins. The focus is on gentle range-of-motion exercises to prevent stiffness and restore mobility.
• Strengthening (Weeks 8-12+): As pain subsides and motion improves, strengthening exercises are introduced to rebuild grip strength and overall wrist stability.
• Functional Activities: Gradually, patients progress to more complex functional tasks, guided by their therapist.

Full recovery can take anywhere from 3 to 6 months, with continued improvements possible for up to a year. Adherence to the physical therapy regimen is critical for optimal outcomes.

PRC vs. Wrist Fusion

When faced with severe wrist arthritis, a proximal row carpectomy is often weighed against a total wrist fusion. The choice depends on the specific condition, patient's functional demands, and overall health:

• Proximal Row Carpectomy (PRC):
  • Pros: Preserves some wrist motion, good pain relief, generally quicker return to light activities.
  • Cons: Not suitable for all types of arthritis (e.g., if capitate/radius cartilage is severely damaged), potential for long-term arthritis at the new joint, less stable than fusion for high-demand activities.
• Total Wrist Fusion (Arthrodesis):
  • Pros: Excellent pain relief, highly stable, durable, suitable for severe, widespread arthritis.
  • Cons: Eliminates all wrist motion (though forearm rotation is preserved), irreversible, longer recovery, impacts ability to perform certain tasks.

For individuals seeking a balance between pain relief and functional motion, and whose anatomy allows, a proximal row carpectomy can be a highly effective surgical option for managing chronic wrist pain and preserving quality of life.