A patella strap, also known as an infrapatellar strap, is a narrow band worn directly across the patellar tendon, just below the kneecap. This orthopedic device is primarily used to manage anterior knee pain, which is discomfort felt in the front of the knee. The strap works by applying targeted compression to the tendon that connects the kneecap (patella) to the shinbone (tibia). It is commonly seen on athletes participating in activities that involve repetitive jumping, running, or squatting. The primary purpose is to provide relief for conditions like Patellar Tendinitis, often called Jumper’s Knee, by reducing strain on the injured tendon during physical activity.
The Core Mechanism of Action
The biomechanical effectiveness of the patella strap centers on the concept of tendon unloading and force redistribution. When the quadriceps muscle contracts, the force is transmitted through the patella and down the patellar tendon to extend the lower leg. Repetitive, high-force activities can place excessive tensile stress on the tendon, leading to irritation and pain.
The strap applies a localized, external pressure point onto the patellar tendon. This pressure shortens the effective length of the tendon and alters the angle at which the tendon pulls on the kneecap, known as the patella-patellar tendon angle (PPTA). Scientific analysis shows that increasing this angle decreases the localized strain experienced by the tendon tissue, especially in the area commonly affected by Jumper’s Knee.
By changing the angle and direction of the quadriceps force, the strap effectively creates a new, temporary origin point for the tendon force, proximal to the strap itself. This shifts the mechanical stress away from the painful or inflamed section of the tendon and its insertion site. The result is a reduction in the tensile load on the irritated tissue, which translates directly into less pain during movement and activity.
The strap does not physically push the kneecap upward, but rather works by subtly modifying the forces acting on the knee’s extensor mechanism. Studies have confirmed that wearing the strap results in a significant reduction in patellar tendon strain, which is directly linked to the experienced pain relief. This mechanism allows individuals to participate in activities with less discomfort, supporting continued rehabilitation.
Conditions That Benefit From Patella Straps
Patella straps are beneficial for several conditions rooted in excessive traction or strain on the knee’s extensor apparatus.
Patellar Tendinitis (Jumper’s Knee)
The most common condition treated is Patellar Tendinitis, or Jumper’s Knee, which involves inflammation and micro-tears in the patellar tendon due to chronic overuse from activities like basketball or volleyball. The strap’s ability to unload the tendon provides immediate symptomatic relief for this diagnosis.
Osgood-Schlatter Disease
The strap is frequently recommended for managing pain associated with Osgood-Schlatter Disease, a common cause of knee pain in growing adolescents. This condition involves inflammation and irritation at the tibial tuberosity, the growth plate where the patellar tendon inserts into the shinbone. The strap lessens the pull on this sensitive insertion site, reducing the traction and subsequent pain experienced by the growing bone and cartilage.
Patellofemoral Pain Syndrome (Runner’s Knee)
For Patellofemoral Pain Syndrome (PFPS), the strap can offer relief by subtly influencing patellar tracking. While PFPS involves pain around or under the kneecap, the targeted pressure from the infrapatellar band may help to stabilize the patella and encourage proper alignment during movement. This reduction in movement variability contributes to decreased pain, especially during activities like climbing stairs or running.
Selecting and Wearing the Strap Correctly
Proper selection and placement of the patella strap are paramount to achieving the desired biomechanical effect and pain relief. The strap must be positioned directly over the patellar tendon, sitting just below the bottom edge of the kneecap. Misplacement, even by a small distance, can negate the strap’s ability to alter the tendon’s force angle and reduce strain.
The strap should be snug enough to apply firm, targeted pressure to the tendon, which is often facilitated by a central pad made of foam or gel. However, it is important to avoid overtightening, as the strap should never feel like a tourniquet or cause numbness, tingling, or a change in circulation to the lower leg.
When considering design, straps typically feature either a flat or a tubular pressure pad. The tubular design is often preferred as it can provide more focused, consistent compression to the tendon. In most cases, the strap should be worn only during physical activity, such as during a run, practice, or game, to manage symptoms. It is not intended for long-term, all-day wear, as continuous reliance can potentially mask underlying mechanical issues that require dedicated physical therapy and strengthening.