Patella tendon pathology, commonly known as patellar tendinopathy or jumper’s knee, is a condition that frequently affects athletes, particularly those participating in jumping sports such as basketball or volleyball. The condition is characterized by pain in the patellar tendon, which connects the kneecap (patella) to the shinbone (tibia).

Anatomy and Function of the Patella Tendon

The patella tendon is a very thick tendon and attaches from the bottom of the patella ( kneecap) to the shin bone. The patella tendon plays a pivotal role in facilitating knee extension, making it an integral part of many athletic movements. When you jump, land, or even walk, the patella tendon absorbs and redistributes forces to protect the knee and facilitate movement.

Causes of Patellar Tendinopathy

Patellar tendinopathy typically arises due to chronic overload, which means that the tendon faces repetitive and excessive strain over time. Such overload can lead to micro-tears in the tendon. When these micro-tears do not have adequate time to heal, they can lead to degenerative changes, inflammation, and pain. Some common contributing factors include:

• Training errors: Rapid increase in training intensity or volume, or a new and different training regime
• Biomechanical issues: Such as poor landing or jumping technique, muscular imbalances, or misalignment and foot biomechanics.
• External factors: Hard playing surfaces or inappropriate footwear.

Symptoms of Patellar Tendinopathy

The hallmark symptom is pain at the front of the knee, specifically over the patellar tendon. This pain typically seems to get better as you start activity, then once cooled down the knee becomes stiiff and painful.

Mornings typically are more painful and stiff and can take a period of time, usually 30 mins or so to start feeling better.

Over time, the pain might become more persistent, even during rest.

What’s happening at a cellular level

1. Inflammatory Markers in Tendinopathy

Recent research suggests that while tendinopathy might not show classical signs of inflammation (heat, redness, swelling), there may be a presence of inflammatory mediators at the cellular level, especially in the earlier stages of the pathology.

• Cytokines: Pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α), have been identified in chronic tendinopathic tissues. These cytokines can stimulate the production of matrix metalloproteinases (MMPs), which can degrade the extracellular matrix of tendons.
• Matrix Metalloproteinases (MMPs): Enzymes like MMP-9 and MMP-2 are more prevalent in tendinopathic tissues. They play a role in collagen degradation, contributing to the tendon’s weakened structure.
• Neovascularization: The growth of new blood vessels into tendinopathic tissues has been observed. These vessels bring along nerve endings and inflammatory cells, which may contribute to pain and the release of inflammatory mediators.

2. Neurogenic Markers in Tendinopathy

The presence of increased nerve fibers in tendinopathic tissue has led to the exploration of neurogenic factors in tendinopathy.

• Substance P: This neuropeptide is associated with pain transmission. Increased levels of Substance P have been found in tendinopathic tendons, suggesting it might play a role in the pain and tissue response observed in tendinopathy.
• Neurotrophins: These are a family of proteins that induce the survival, development, and function of neurons. Nerve growth factor (NGF) is a notable neurotrophin identified in higher concentrations in tendinopathic tissues. It can sensitize nociceptors and might be involved in the pain mechanism of tendinopathy.
• Glutamate: This neurotransmitter has also been found in increased concentrations in tendinopathic tendons, suggesting a potential role in nociception and pain in tendinopathy.

The presence of neurogenic markers in tendinopathic tissue challenges the traditional belief that tendinopathy is purely a degenerative, inflammatory condition. It suggests a more complex interplay of factors. This understanding can pave the way for targeted treatments, addressing not only the structural degeneration but also the inflammatory and neurogenic aspects of tendinopathy.

Evidence-Based Treatment Approaches

1. Load Management

Modifying activity is the most important step in treating any tendinopathy. This doesn’t mean stopping all activities, but rather scaling back on the intensity, frequency, or duration to a level where pain is manageable and function can continue. Gradually reintroducing load can help the tendon adapt and strengthen and will see the best long-term outcome.

Understanding Load

In the realm of musculoskeletal health, ‘load’ refers to the stress or strain a particular activity places on a body structure, particularly muscles, bones, and tendons. For the patellar tendon, it would include both external forces (e.g weight of the body, resistance in weightlifting) and internal forces (e.g contraction of the quadriceps).

The Goldilocks Principle

Load management is often likened to the Goldilocks principle – the load shouldn’t be too little or too much, it should be just right. Here’s why:

• Too little load: Under-loading can result in decreased tendon resilience, strength, and capacity. It’s equivalent to not challenging the tendon enough to promote beneficial adaptive changes.
• Too much load: Overloading can induce or exacerbate tendon injuries. When exposed to excessive stress, the tendon might not have ample time or resources to repair, leading to microtraumas and subsequently, tendinopathy.

Graded Exposure to Load

One of the most effective strategies in treating and preventing tendinopathies is graded exposure to load:

• Baseline Establishment: Understand the current capacity of the tendon. This might involve functional tests or simply identifying at what point during activity pain emerges.
• Incremental Increases: Once the baseline is established, the tendon is subjected to slightly greater loads in a controlled manner. This could involve progressively heavier resistance training, increased repetitions, or additional training sessions.
• Monitoring & Feedback: Constantly assess pain, function, and response after each increment. This feedback loop helps in deciding the subsequent progression or the need for modification.

Addressing Acute vs. Chronic Load

Load management is not just about the immediate (acute) load but also considers the cumulative (chronic) load:

• Acute Load: The stress placed on the tendon in a short period, usually a single training session or activity.
• Chronic Load: The accumulated stress over an extended period, typically weeks or months.

Maintaining a balance between the two is paramount. Sudden spikes in acute load without a corresponding increase in chronic load resilience often lead to injuries.

Load Modulation Techniques

Various techniques can help modulate load effectively:

• Alternate Activities: Mixing high-impact activities (like jumping or sprinting) with low-impact ones (swimming or cycling) can offer the tendon relative rest.
• Strength Training: Incorporating eccentric exercises, isometrics, and concentric training at different phases can foster tendon strength and resilience.
• Recovery Protocols: Ensuring adequate rest, sleep, and nutritional support plays a pivotal role in how tendons respond to loading.

Educating the Patient/Athlete

Load management isn’t just a clinical exercise. Educating the patient or athlete about the rationale behind each step ensures adherence, understanding, and optimal outcomes. They become active participants in their rehabilitation journey. Load management, when systematically approached, is a cornerstone in treating patellar tendinopathy. By understanding the tendon’s thresholds and modulating activity in a structured manner, clinicians can guide their patients towards pain-free function and enhanced performance.

To learn more about this and ways to put this theory into practice read our blog Rehab and Adaptation Progression.

2. Isometric Exercises

Holding a muscle in a non-moving contraction can help reduce pain during the initial phases of rehab. For the patellar tendon, this could involve holding a half-squat position for a set duration.

3. Eccentric Exercises

Studies have shown that eccentric (lengthening) exercises can help stimulate tendon healing and strength. The decline squat is a popular choice for patellar tendinopathy. This involves standing on a decline board (or a thick book) and slowly bending the knees, emphasizing the downward phase. Concentric exercises are also important to incorporate in any rehab program.

4. Soft Tissue Therapies

Manual techniques, including massage and instrument-assisted soft tissue mobilization may be helpful adjuncts to management but are not a stand alone treatment.

5. Shockwave Therapy

Extracorporeal shockwave therapy (ESWT) has been found to be effective in some cases and there is some reasonable evidence of tis effectiveness in treating patella tendinopathy. Other modalities show very limited benefit.

6. Taping or Bracing

Some athletes find relief with patellar bracing which can provide support and decrease strain on the tendon.

• Patellar Straps: Positioned just below the kneecap, they potentially redistribute force, offering immediate pain relief for many athletes during strain-inducing activities. This can also be achieved by using patellar taping techniques.
• Knee Sleeves: Providing compression, these enhance proprioception and can mitigate pain and stiffness. However, their relief isn’t as tendon-specific as straps.

7. Strength and Conditioning

Addressing muscular imbalances and enhancing overall leg strength can aid in preventing future episodes and improving function.

8. Platelet-Rich Plasma (PRP) Injections

While still a topic of debate and research, some studies suggest PRP, which involves injecting the patient’s own platelets into the injured tendon, can promote healing.

9. Surgery

Reserved for cases that do not respond to conservative treatments. Surgical options aim to remove degenerated tissue or stimulate healthy tissue growth.

Prevention and Long-Term Management

• Gradual Progression: Increase training loads slowly, allowing the body, especially tendons, time to adapt.
• Strength Training: Regular strength and conditioning, focusing on lower limb muscles, can protect the patellar tendon from excessive strain.
• Flexibility: Maintaining flexibility in the quadriceps, hamstrings, and calf muscles can reduce tension on the patellar tendon.
• Good Technique: Proper jumping and landing techniques can significantly decrease the risk of tendinopathy.

In conclusion, patellar tendinopathy, while common among athletes, is manageable and treatable with the right approach. A multidisciplinary team involving a sports therapist, strength and conditioning coach, and potentially an orthopedic consultant can guide an athlete through recovery and back to peak performance. Always consult with a healthcare professional for an accurate diagnosis and personalized treatment plan.