One of the common findings in chronic patellar tendinopathy is increased vascularity. If you look at an irritated patellar tendon with an ultrasound, you may see significantly more blood flow than you would expect in a normal, healthy tendon.
This is usually described as neovascularization or angiogenesis. and considered “bad”.
For years, this has been discussed as one of the pathological features of patellar tendinopathy. Healthy tendons have relatively low vascularity, while chronically irritated tendons often have increased vascularity.
It’s easy to assume the increased blood vessels are part of the problem.
I don’t think that tells the whole story.
🩸 Angiogenesis Is Normal — At First
Angiogenesis is a normal part of tissue repair. If the patellar tendon is damaged, the body needs oxygen, nutrients, immune activity, and signaling molecules in that area. Increasing vascular supply is one way of accomplishing that.
VEGF (vascular endothelial growth factor) plays a major role in this process. Following injury, increased VEGF signaling promotes the development of new blood vessels around the damaged tissue.
None of this is inherently pathological. Early in the healing process, it’s exactly what we expect the body to do.
The more interesting question is why we continue to see increased vascularity months later in chronic patellar tendinopathy.
🏋️ Why Would the Patellar Tendon Keep Increasing Blood Flow?
Patellar tendons respond to their mechanical environment.
Every time you walk, squat, jump, land, accelerate, or decelerate, force travels through the patellar tendon. The tendon has to tolerate that force and adapt to it.
When those forces are appropriate, we get adaptation. When the tendon repeatedly encounters forces beyond its current capacity, we get a different response.
This is where persistent vascularity needs to be viewed differently.
Instead of assuming the blood vessels themselves are bad or unhealthy, increased vascularity ACTUALLY indicates that the tendon is still actively attempting to remodel.
The body is simply not done healing.
For example, an athlete can regain basic quad strength after a patellar tendon injury but still have poor force absorption, decreased reactive strength, limited eccentric capacity, or an inability to tolerate rapid loading.
That athlete may feel considerably better during everyday activity but still expose the patellar tendon to forces it isn’t prepared to handle during jumping, landing, sprinting, or change‑of‑direction work.
If the mechanical problem remains, it makes sense that the biological repair response may remain as well.
🔥 Vascularity Doesn’t Equal Pain
One argument against increased vascularity is that new blood vessel formation can occur alongside sensory nerve ingrowth.
This has led to the idea that neovascularization contributes directly to tendon pain.
There is probably some truth to this. More nerve fibers in an irritated area certainly provide additional opportunities for pain signaling, but vascularity and pain aren’t interchangeable.
We can find abnormal tendon structure and increased vascularity in people who aren’t experiencing significant pain. We can also see painful patellar tendons without dramatic nerve in-growth.
This is important clinically because imaging findings don’t always correlate well with symptoms.
The presence of blood vessels tells us something is happening biologically. It doesn’t necessarily tell us what is causing the patient’s pain.
🧪 Should We Increase or Decrease Angiogenesis?
I looked for ways to do this for years.
There are nutrients, herbs, medications, and other compounds that can influence VEGF and angiogenic signaling. Some increase it. Others suppress it.
So which direction do we want to go with a patellar tendon?
After both trying strategies and rethinking it all a thousand times, I don’t think the goal should be either one.
Trying to artificially maximize angiogenesis throughout the entire healing process doesn’t make sense. Neither does assuming that chronic tendon vascularity needs to be suppressed simply because it is present.
The goal should be to support normal healing while correcting the reason the tendon continues to require remodeling.
Early after injury, increased angiogenesis is a normal component of repair. As the tendon remodels and becomes capable of handling normal forces again, the demand for that increased vascular response should decrease.
If vascularity remains elevated, I would first want to know why the tendon still thinks it needs to repair.
🏃 This Is Primarily a Loading Problem
This is why patellar tendon rehabilitation can’t stop at basic strengthening.
Getting someone from a painful bodyweight squat to a pain‑free squat is progress, but it doesn’t mean the patellar tendon is ready for sport.
Eventually that tendon needs to tolerate high levels of force at very high speeds.
That means rehabilitation has to progress through appropriate loading, isometrics, eccentric force absorption, heavier strength work, rate of force development, reactive loading, jumping, landing, and eventually sprinting or sport‑specific activity.
If the tendon never regains the ability to handle the forces that originally exceeded its capacity, then simply reducing pain doesn’t solve the entire problem.
The tissue can remain in a state of continued remodeling.
Increased vascularity is simply be one sign of that process.
📡 What Doppler Is Actually Telling Us
When I see increased ultrasound signal in a chronically irritated patellar tendon, I don’t immediately view it as something that needs to be eliminated.
I view it as information.
It tells me the tendon is biologically active.
Then I want to know why.
- Can the athlete absorb force?
- How does quad strength compare side to side?
- What happens with rapid loading?
- Can the athlete tolerate jumping?
- Can they tolerate repeated jumping?
- Can they sprint?
- How does the tendon respond the following morning?
Those answers give me considerably more information than vascularity alone.
If mechanical capacity improves and the tendon successfully remodels, I would expect the biological demand for persistent vascularization to eventually decrease as well.
🎯 Don’t Treat the Blood Vessel. Treat Why It’s There.
This is the main point.
The body has a reason for angiogenesis.
After injury, increasing vascular supply is one of the mechanisms available to support tissue repair. Finding those vessels later in the rehab process doesn’t mean the body made a mistake.
Persistent angiogenesis tells us that there is persistent tendon stress, incomplete remodeling, or a mechanical demand that continues to exceed the capacity of the tissue. (there is still a problem)
So let this article be the first to tell you chronic inflammation or increased angiogenesis isn’t the problem but rather it is clear evidence that the problem hasn’t been completely solved yet and you need to keep looking.
If you are ready to end patellar tendonitis for good, reach out. We have programs locally and remote.
FAQ: Patellar Tendonitis, Tendinopathy & Angiogenesis