What is the procedure and rehabilitation process for radial head replacement?

Radial Head Replacement: Procedure and Rehabilitation

Indications for Radial Head Arthroplasty

Radial head replacement is indicated for comminuted, non-reconstructible radial head fractures (Mason III-IV) and complex elbow injuries with associated ligamentous instability, including terrible triad injuries and Essex-Lopresti lesions. 1, 2, 3

Specific Clinical Scenarios:

• Mason III fractures (comminuted fractures with >3 fragments that cannot be reconstructed with internal fixation) 4, 5
• Mason IV fractures (radial head fractures with elbow dislocation) 4
• Complex elbow trauma with concurrent ligamentous injuries (medial/lateral collateral ligament ruptures) with or without coronoid process fractures 2, 4
• Failed osteosynthesis requiring secondary radial head replacement 1
• Essex-Lopresti injuries where radial head excision would compromise forearm stability 5

Diagnostic Workup:

• Obtain CT imaging when radiographs show abnormal radiocapitellar alignment to fully characterize fracture morphology and identify associated injuries 6
• Specifically assess for coronoid process fractures on CT, as these indicate severe instability and are commonly missed on plain radiographs 6

Surgical Technique

Approach:

The Kocher interval (between anconeus and extensor carpi ulnaris) is the standard surgical approach for radial head replacement. 1, 5

Key Technical Steps:

• Accurate sizing of the prosthesis head is critical to prevent complications including oversizing-related osteolysis, capitellar wear, and overstuffing of the radiocapitellar joint 1, 5
• Stem length selection matters: Longer-stem implants may reduce complications and loosening 5
• Assess and address all associated injuries during the same procedure, including ligamentous repairs and coronoid fixation if present 2, 4

Common Pitfalls to Avoid:

• Do not oversize the prosthesis head, as this leads to extensive osteolysis around the stem and potential implant failure 1
• Do not miss coronoid fractures, which require CT imaging for identification and indicate severe instability 6
• Ensure proper stem fixation to minimize periprosthetic lucencies and osteolysis 4, 5

Postoperative Rehabilitation Protocol

Immediate Postoperative Period (0-3 Weeks):

Apply plaster splint immobilization from metacarpophalangeal joints to shoulder for 2-3 weeks postoperatively. 1, 5

Initiate active finger motion exercises immediately to prevent hand stiffness, which is a functionally disabling complication 6, 7

Early Mobilization Phase (3-4 Weeks):

Begin early elbow motion exercises after splint removal at 2-3 weeks to optimize functional outcomes 1, 2

The goal is early rehabilitation with active range of motion to prevent stiffness while allowing soft tissue healing 2, 3

Radiographic Monitoring:

Obtain radiographs at 3 weeks post-surgery to assess implant position and early healing 7

Repeat imaging at 6 months to evaluate for periprosthetic lucencies, osteolysis, or signs of loosening 1, 4

Expected Functional Outcomes

Range of Motion at 6-12 Months:

• Mean flexion-extension arc: 124-130° (extension lag typically 7-8°) 1, 4
• Mean pronation: 74-80° 4, 5
• Mean supination: 72-86° 4, 5
• Grip strength: 96% of contralateral side 4

Functional Scores:

• Mayo Elbow Performance Score (MEPS): Mean 88-92.5 points (80% excellent, 17% good results) 1, 4, 5
• DASH score: Mean 11.2 (lower scores indicate better function) 5
• Broberg-Morrey scores: 33% excellent, 44% good, 23% fair 4

Complications and Long-Term Considerations

Early Complications (Rare at 6 Months):

• No complications requiring revision surgery typically occur in the first 6 months with proper technique 1
• Elbow joint stability is maintained in properly selected and executed cases 4, 5

Late Complications (Require Ongoing Surveillance):

• Periprosthetic lucencies or osteolysis occur in approximately 19-38% of cases (6 of 32 patients in one series), though often without clinical signs of loosening 4, 5
• Stem loosening may develop, particularly with shorter stems or oversized heads 1, 5
• Heterotopic ossification can occur in some patients 5
• Catastrophic failures including prosthesis disconnection or shaft fracture are rare but reported 1

Critical Point:

Radiological signs of stem loosening do not necessarily correlate with poor functional outcomes, and asymptomatic lucencies may not require immediate intervention 5