Brace Solution for Knee Instability after ACL Injury

The anterior cruciate ligament (ACL) is one of the most commonly-injured ligaments of the knee. Approximately 100,000 to 200,000 ACL injuries occur per year in the USA. The ACL controls anterior translation of the tibia and restraint of tibial rotation, as well as varus or valgus stress. After injury, people will experience different grades of knee instability and increased likelihood of degenerative knee arthritis, which will not only limit activities but also bring pain and disability.

Knee instability and its effects

Most people feel the knee become unstable or “giving out” after ACL injury, a feeling which may continue throughout the healing process. Knee instability may lead to further trouble if not treated well. Here are some of its characteristics:

• Combined injuries

Other structures are often damaged during an acute ACL injury. Associated structures that are commonly injured include the meniscus, joint capsule, articular cartilage, subchondral bone (bone bruise), and other ligaments.

• Joint effusion

After ACL tears, inflammation presents immediately and leads to joint hemarthrosis, then enlarges joint space.

• Altered muscle function

Muscles provide dynamic stability for the knee joint, and any changes of muscle strength or coordination after injury will affect biomechanics during movement.

In recent years, more and more research has shown that early mobilization and rehabilitation are helpful and effective for ACL injuries. Patients participate in rehabilitation programs or daily activities earlier than before. Safe movement under persistent instability should be the first concern.

Interventions for improving knee stability

Treatments for ACL injuries may include surgery or rehabilitation, both are aimed at restoring joint stability. Surgical interventions rebuild static stability by implanting a replacement tissue, while rehabilitative interventions reinforce dynamic stability through different approaches:

• Protection - Provide external compression or restraint to prevent excessive joint motion.
• Muscle strengthening - Increase muscle strength of lower extremity to decrease stress on ligaments.
• Proprioception - Improve sensory feedback to detect joint motion more accurately.  
• Coordination - Enhance muscle coordination to enhance movement control.

Product recommendation

All management strategies for ACL injury are aimed at increasing tissue healing and restoring joint stability. According to different grades of instability, different supports are appropriate to the demands of the healing process.

References: