How do you immobilize a long finger after a sagittal band repair?

Immobilization Protocol for Long Finger Sagittal Band Repair

Immobilize the long finger in extension at the MCP joint with the wrist in neutral to slight extension (0-15 degrees) for 4-6 weeks, allowing immediate active PIP and DIP motion while restricting MCP flexion. 1, 2

Splinting Position and Configuration

MCP Joint Position

• Position the MCP joint in full extension (0 degrees) to minimize tension on the repaired sagittal band 1, 3
• The repaired sagittal band experiences greatest stress during MCP flexion, particularly full flexion which generates up to 50 mm Hg of pressure deep to the band 3
• Extension positioning keeps sagittal band fibers perpendicular to the extensor tendon, reducing strain on the repair 3

Wrist Position

• Maintain the wrist in neutral to slight extension (0-15 degrees) 4, 5
• Wrist flexion significantly increases extensor tendon instability after sagittal band injury and should be avoided 3
• Neutral wrist positioning prevents additional stress on the repair site 3

Adjacent Joint Management

• Allow immediate active motion of the PIP and DIP joints to prevent finger stiffness 6
• Finger stiffness is one of the most functionally disabling complications and can require extensive therapy 6
• The splint should only restrict MCP joint motion while permitting full flexion and extension of the interphalangeal joints 1, 5

Splint Type and Construction

• Use a rigid dorsal or volar splint that immobilizes the MCP joint in extension while leaving the PIP and DIP joints free 1, 2
• The splint should be padded to cushion the repair site 6
• Ensure the splint is comfortably tight but allows a finger to be slipped underneath to prevent circulatory compromise 6, 7

Duration of Immobilization

• Continue strict MCP extension immobilization for 4-6 weeks based on surgical findings and repair strength 1, 2
• Patients treated within 3 weeks of injury achieve satisfactory results with conservative splinting alone 1
• Chronic cases (mean 51 days post-injury) still achieve excellent outcomes with surgical repair followed by appropriate immobilization 2

Critical Pitfalls to Avoid

• Never allow MCP flexion during the initial 4-6 week healing period, as this generates maximum stress on the sagittal band repair (up to 50-57 mm Hg pressure) 3
• Avoid wrist flexion, which exacerbates extensor tendon instability and can compromise the repair 3
• Do not immobilize the PIP and DIP joints, as this leads to severe finger stiffness requiring extensive therapy and potentially additional surgical intervention 6
• Avoid removable splints for acute repairs, as rigid immobilization is preferred for optimal healing 8

Monitoring During Immobilization

• Instruct patients to watch for blue or extremely pale discoloration of the finger, which indicates a medical emergency requiring immediate evaluation 6, 7
• Apply cold therapy for 15-20 minutes several times daily during the first week to reduce pain and swelling 6, 7
• Ensure patients perform active PIP and DIP range of motion exercises multiple times daily to prevent stiffness 6

Anatomical Rationale

The long finger is the most commonly affected digit in sagittal band injuries, typically involving radial-sided disruption 1, 3. Proximal sagittal band compromise contributes more to extensor tendon instability than distal disruption 3. Complete radial sagittal band sectioning produces tendon dislocation, while partial proximal sectioning causes subluxation 3. This anatomical understanding supports the need for strict MCP extension positioning to protect the repair while allowing interphalangeal joint motion to prevent complications.