What is a knee extension splint used for in patients with knee injuries or surgery, including those with knee fractures, ligament sprains, or osteoarthritis?

Knee Extension Splint Uses

A knee extension splint is primarily used to immobilize the knee in full extension for acute traumatic injuries requiring stabilization, post-surgical protection to prevent reinjury, and management of specific conditions including quadriceps rupture, patellar tendon rupture, medial collateral ligament rupture, patellar fracture or dislocation, and other acute knee trauma. 1, 2

Primary Indications

Acute Traumatic Injuries

• Knee extension splints are indicated for suspected fractures to stabilize the extremity in the position found, reduce pain, prevent further injury, and facilitate transport to medical facilities. 1
• The 2024 American Heart Association and American Red Cross guidelines emphasize that splinting can be useful to reduce pain and risk for further injury when a fracture is suspected. 1
• If a fractured extremity appears blue, purple, or pale, this indicates a limb-threatening injury requiring immediate emergency activation. 1

Post-Surgical Protection

• Knee immobilizing splints are used after knee surgery to prevent reinjury during the early healing phase. 2
• The splint maintains the knee in a protected position while soft tissues heal and before active rehabilitation begins. 2

Specific Acute Conditions Requiring Extension Immobilization

• Quadriceps tendon rupture (acute or presurgical management) 2
• Patellar tendon rupture (acute or presurgical management) 2
• Medial collateral ligament rupture 2
• Patellar fracture or dislocation 2
• Other acute traumatic knee injuries requiring immobilization 2

Key Principles of Application

Splinting Technique

• Splint the injured extremity in the position found unless straightening is necessary to facilitate safe transport. 1
• Do not attempt to straighten an angulated fracture, as there is no evidence this shortens healing time or reduces pain, and it carries risks of nerve injury. 1
• If splinting is used, ensure adequate padding to cushion the injury. 1

When to Activate Emergency Services

• Immediately activate emergency medical services if the injured extremity is blue, purple, or pale, as this indicates poor perfusion and potential limb-threatening injury. 1
• If a fracture is associated with severe bleeding, follow hemorrhage control protocols first. 1

Important Limitations and Cautions

Prolonged Immobilization Risks

• Extended immobilization in extension can lead to knee extension contractures, which are difficult to treat and require extensive rehabilitation. 3
• Historical data from war injuries shows that prolonged immobilization (mean 5 months) resulted in severe extension contractures with preoperative motion ranging only from 5° extension to 38° flexion. 3
• Knee extension splints should be used for the shortest duration necessary to achieve initial stabilization and healing. 3, 4

Not Indicated for Chronic Conditions

• Knee extension splints are NOT recommended for chronic osteoarthritis management. 1
• For osteoarthritis, tibiofemoral knee braces that allow controlled motion are strongly recommended instead of rigid immobilization. 1
• Realigning braces with hinges that permit range of motion while providing support are preferred over extension splints for chronic knee conditions. 1

Common Pitfalls to Avoid

• Do not use knee extension splints for prolonged periods without medical supervision, as this significantly increases the risk of extension contractures. 3
• Do not attempt to straighten deformed fractures in the field, as this can cause nerve injury and does not improve outcomes. 1
• Do not use extension splints as a substitute for proper fracture management or as a long-term solution for chronic knee instability. 2, 5
• Ensure proper training in splint application before use, as improper technique may cause harm. 1