What is the step-by-step procedure for open reduction with K-wire (Kirschner wire) fixation for a 1st metacarpophalangeal (MCP) joint dislocation of the right hand?

Open Reduction with K-Wire Fixation for 1st MCP Dislocation of Right Hand

The optimal surgical approach for 1st MCP joint dislocation is open reduction with K-wire fixation through a dorsal approach to minimize risk to neurovascular structures and provide adequate exposure for reduction and fixation. 1

Preoperative Preparation

• Position the patient supine with the affected arm on an arm table
• Administer appropriate anesthesia (regional or general)
• Prepare and drape the right hand in a sterile manner
• Apply a tourniquet to the upper arm and inflate to appropriate pressure
• Obtain fluoroscopic imaging equipment for intraoperative use

Surgical Procedure

Step 1: Approach and Exposure

• Make a 3-4 cm longitudinal or slightly curved dorsal incision centered over the 1st MCP joint
• Carefully dissect through subcutaneous tissue, identifying and protecting the sensory branches of the radial nerve
• Identify the extensor pollicis longus tendon and retract it ulnarly
• Expose the dorsal capsule of the MCP joint

Step 2: Joint Assessment and Reduction

• Incise the dorsal capsule longitudinally or create a flap
• Identify the entrapped volar plate (common obstacle to reduction in complex dislocations)
• Assess for any osteochondral fractures of the metacarpal head or proximal phalanx
• Remove any interposed soft tissue (typically the volar plate) that prevents reduction
• Perform direct visualization of the joint surfaces
• Reduce the MCP joint by applying appropriate traction and pressure to realign the proximal phalanx with the metacarpal head

Step 3: K-Wire Fixation

• Once anatomic reduction is achieved, maintain the position with temporary manual pressure
• Insert a 1.2-1.6 mm K-wire through the proximal phalanx into the metacarpal head
• The wire should be inserted from dorsal-distal to volar-proximal, crossing the MCP joint at approximately 45° angle
• Confirm proper wire placement and joint reduction with fluoroscopy in multiple views
• If needed for additional stability, place a second K-wire parallel to the first

Step 4: Soft Tissue Repair

• Repair any damaged collateral ligaments with non-absorbable sutures
• If the volar plate was split for reduction, repair it with absorbable sutures
• Close the capsule with absorbable sutures
• Bend the exposed end of the K-wire and cut it, leaving sufficient length for later removal

Step 5: Closure and Immobilization

• Close subcutaneous tissue with absorbable sutures
• Close skin with non-absorbable sutures or staples
• Apply sterile dressing
• Place the thumb in a thumb spica splint in slight flexion at the MCP joint

Postoperative Management

• Maintain immobilization for 3-4 weeks
• Remove K-wires at 4-6 weeks postoperatively (can be done in office setting)
• Begin supervised rehabilitation focusing on:
  • Range of motion exercises
  • Proprioception training
  • Progressive strengthening
  • Coordination exercises

Potential Complications

• Stiffness of the MCP joint
• Pin tract infection
• Malunion or nonunion
• Avascular necrosis of the metacarpal head
• Complex regional pain syndrome
• Osteoarthritic changes
• Recurrent instability

Important Considerations

• The dorsal approach is preferred as it reduces risk to palmarly displaced neurovascular structures and provides better exposure of the volar plate 1
• Ensure anatomic reduction with <2mm articular step-off to prevent long-term complications such as osteoarthritis 2
• Functional outcomes are generally excellent with appropriate surgical technique and rehabilitation 3
• For pediatric patients, this technique has shown excellent functional recovery 4
• Ensure no rotational deformity is present after fixation by checking finger alignment during passive flexion

This procedure restores stability to the MCP joint while preserving maximum functionality, which is crucial for thumb function and overall hand dexterity.