Knee Straps: Function, Benefits, and Conditions Treated

What is the function of a knee strap?

A knee strap, often referred to as an infrapatellar strap or patellar tendon strap, primarily functions to provide targeted compression and support to the patellar tendon, aiming to alleviate pain and discomfort associated with conditions like patellar tendinopathy (Jumper's Knee) and Osgood-Schlatter disease.

Understanding the Knee Joint and Patellar Tendon

To fully grasp the function of a knee strap, it's essential to understand the basic anatomy and biomechanics of the knee. The knee is a complex hinge joint formed by the femur (thigh bone), tibia (shin bone), and patella (kneecap). The patella is a sesamoid bone embedded within the quadriceps tendon, which connects the powerful quadriceps muscles on the front of the thigh to the tibia. The portion of this continuous structure that extends from the bottom of the patella to the tibial tuberosity (a bony prominence on the front of the shin) is known as the patellar tendon.

During activities like jumping, running, squatting, and kicking, the quadriceps muscles contract to extend the knee. This force is transmitted through the patella and the patellar tendon. The patellar tendon, therefore, bears significant tensile load and is crucial for knee extension and shock absorption.

Primary Function: Targeted Patellar Tendon Support

The fundamental role of a knee strap is to apply localized compression directly over the patellar tendon, just below the kneecap. This targeted pressure serves several key purposes:

• Load Redistribution and Offloading: By compressing the patellar tendon, the strap can help to slightly alter the angle of pull or distribute the tensile forces acting on the tendon. This effectively reduces the direct strain on the most painful or inflamed area of the tendon, thereby offloading it during movement.
• Vibration Dampening: During high-impact activities, the patellar tendon can undergo significant vibration and oscillation. The strap acts as a counterforce, helping to dampen these vibrations and reduce microtrauma to the tendon fibers.
• Pain Modulation (Gate Control Theory): The constant, mild pressure exerted by the strap may stimulate mechanoreceptors in the skin and underlying tissues. This sensory input can interfere with the transmission of pain signals to the brain, providing a pain-relieving effect consistent with the gate control theory of pain.
• Proprioceptive Feedback: While not its primary function, the presence of the strap can enhance proprioception (the body's awareness of its position in space) around the knee. This increased sensory feedback might subtly influence muscle activation patterns, potentially leading to more controlled movements and reduced stress on the tendon.

How a Knee Strap Differs from a Full Knee Brace

It's important to distinguish a knee strap from a full knee brace. A knee strap is a narrow band specifically designed to target the patellar tendon. In contrast, a full knee brace typically covers a larger area of the knee, often providing broader support for ligaments (e.g., ACL, MCL), cartilage, or overall joint stability. Knee straps are not designed to stabilize the knee joint itself or prevent significant lateral or rotational movements.

Conditions Benefiting from Knee Strap Use

Knee straps are most commonly recommended for conditions characterized by pain and inflammation of the patellar tendon or its attachment points:

• Patellar Tendinopathy (Jumper's Knee): This is the most common indication. It involves inflammation or degeneration of the patellar tendon, often due to repetitive strain from activities involving jumping and sudden acceleration/deceleration (e.g., basketball, volleyball, running). The strap helps to manage symptoms during activity.
• Osgood-Schlatter Disease: Primarily affecting adolescents during growth spurts, this condition involves inflammation of the growth plate at the tibial tuberosity, where the patellar tendon attaches. A knee strap can help reduce the pull and stress on this sensitive area, alleviating pain.
• Patellofemoral Pain Syndrome (PFPS) (in some cases): While PFPS is a broader condition often related to patellar tracking issues, some individuals find minor relief from a knee strap if their pain is localized to the lower pole of the patella or patellar tendon insertion. However, a full knee brace or specific taping techniques are often more effective for general PFPS.

Limitations and Important Considerations

While a knee strap can be an effective tool for symptomatic relief, it's crucial to understand its limitations:

• Symptomatic Relief, Not a Cure: A knee strap addresses the symptoms (pain) by offloading the tendon, but it does not resolve the underlying cause of the tendinopathy. The root cause often involves factors like muscle imbalances, biomechanical deficiencies, improper training loads, or inadequate recovery.
• Importance of Rehabilitation: For long-term recovery and prevention of recurrence, a comprehensive rehabilitation program is essential. This typically includes:
  • Strengthening exercises: Focusing on quadriceps, hamstrings, glutes, and calf muscles.
  • Flexibility and mobility work: Addressing any tightness in the quadriceps or hip flexors.
  • Load management: Gradually increasing activity levels.
  • Technique correction: Addressing biomechanical flaws in sport-specific movements.
• Proper Fit is Key: An ill-fitting strap can be ineffective or even cause discomfort. It should be snug enough to provide compression but not so tight as to restrict circulation or cause numbness.
• Not for All Knee Injuries: Knee straps are unsuitable for ligamentous injuries (e.g., ACL, MCL tears), meniscal tears, or significant joint instability, which require different types of bracing or medical intervention.
• Potential for Over-reliance: Relying solely on a strap without addressing underlying issues can delay recovery and potentially worsen the condition in the long run.

Proper Application and Sizing

A knee strap should be worn directly below the kneecap, snug against the skin. Most designs feature an adjustable strap with a buckle or hook-and-loop closure to allow for customized compression. It's generally recommended to apply the strap while the knee is slightly bent, then tighten it to a comfortable level that provides support without causing pain or restricting movement.

When to Seek Professional Advice

While a knee strap can offer immediate relief, it's always advisable to consult with a healthcare professional, such as a physical therapist, sports medicine physician, or orthopedist, especially if:

• Pain persists or worsens despite using the strap.
• You experience swelling, bruising, or instability in the knee.
• You are unsure about the cause of your knee pain.
• You need guidance on a comprehensive rehabilitation plan.

Conclusion

A knee strap serves as a valuable adjunct in the management of patellar tendinopathy and related conditions by providing targeted compression to the patellar tendon. Its primary function is to offload stress, dampen vibrations, and modulate pain, allowing individuals to continue with daily activities or participate in sports with reduced discomfort. However, it is crucial to remember that a knee strap is a supportive tool for symptomatic relief and should be used in conjunction with a proper diagnosis and a comprehensive rehabilitation strategy to address the underlying causes of knee pain for lasting recovery.