Patellar Tendinopathy in Footballers: What Doppler Ultrasound Shows
In footballers, patellar tendinopathy usually develops after years of jumping, changes of pace, sudden stops and repeated strikes of the ball: movements that load the patellar tendon again and again, beyond what it's able to tolerate and repair at any given moment. When that pain becomes chronic and we order a Doppler ultrasound, a finding often surprises the player themselves: newly formed blood vessels that appear to “invade” the damaged area of the tendon. Why do they appear, are they a problem, and what do we do with that information when planning recovery?
What is patellar tendinopathy in the context of football?
The patellar tendon connects the kneecap to the tibia and transmits the force of the quadriceps on every shot, jump, stop or change of direction. In football, the combination of repeated load, hard surfaces, changes of pace and seasons without enough rest is fertile ground for this tendon to start degenerating: it loses part of the normal organisation of its collagen fibres, and localised pain appears, almost always at the lower pole of the kneecap.
Why do these blood vessels form in the tendon?
A healthy tendon has very little blood supply in its main body; it's nourished mainly through the paratenon that surrounds it. When the tendon enters a process of chronic degeneration, the body tries to repair it and, to do so, triggers an angiogenesis process: new blood vessels grow from the surrounding tissue — in the knee, very often from Hoffa's fat pad — and penetrate the paratenon and even the tendon itself. On Doppler ultrasound, this shows up as small newly formed vessels “invading” the damaged area, almost always next to the local tendon deformity we usually describe as a ‘donkey belly’.
This vascular growth is usually accompanied by a parallel growth of small sensory nerve fibres, a process called neoinnervation. This combination of new vessels and nerves in an area that previously had almost none is one of the explanations that best fits why a chronic tendinopathy can hurt so much, even when the tendon, taken as a whole, isn't torn or severely damaged.
Are these blood vessels harmful?
They are not “harmful” in the sense of damaging the tendon or posing a risk to general health. They are, rather, the visible sign that the tendon got stuck in an unfinished repair attempt that hasn't resolved: the normal healing process — inflammatory phase, then regenerative, then remodelling — hasn't been completed, and the tissue remains in a prolonged intermediate phase. Neovascularisation isn't the original cause of the problem, but a marker of that stalled healing, and through the associated neoinnervation it may help keep the area sensitive to pain.
Does the presence of these vessels indicate the state or progression of the condition?
It's a useful piece of information, but not an exact rule. In general terms, greater neovascularisation tends to go along with more chronic or more irritated presentations, and many physiotherapists use it as one of the markers to assess whether a tendon is in a more active or a more stable phase. Manual compression over the vascular area reproducing pain, as often happens in the clinic, reinforces that correlation in the individual case.
That said, the relationship between neovascularisation and symptoms isn't perfect: some tendons with very visible newly formed vessels cause little pain, and some painful tendons show less Doppler signal than expected. That's why at KINEO Benidorm we don't base a clinical decision on this finding alone: we weigh it together with the tendon's fibrillar pattern, whether or not calcification is present, the patient's clinical picture and how it evolves with treatment.
How does the physiotherapist plan recovery with this information?
Knowing that there's active neovascularisation, and exactly where it's concentrated, changes several decisions within the Itinerario KINEO:
Sets the priority goal for the treatment cycle: when neovascularisation is the main source of irritation, the initial goal shifts to reducing that pathological vascular activity, rather than forcing high loads on the tendon.
Helps dose the training load: in phases with very active neovascularisation, we prioritise avoiding the movements that most compress or overload the tendon, so as not to perpetuate the irritation, while keeping up the activity the tendon does tolerate.
Guides which ultrasound-guided techniques may help: precisely locating the vessels and, if present, the associated calcification, allows ultrasound-guided techniques to be planned in a targeted way, in the cases where they're indicated.
Serves as a reference for follow-up: repeating the Doppler ultrasound over the course of treatment, together with pain scales, lets us check whether that pathological vascularity is decreasing and, with it, whether the tendon is moving towards a more stable phase.
Helps decide the pace of return to sport: the progressive return to football-specific movement is planned using objective criteria, not just a subjective feeling of improvement, combining clinical progress with imaging findings.
You can find out more about these tools on our pages for invasive physiotherapy (EPTE) and shock wave therapy in Benidorm, and about the general approach to this injury in our article on patellar tendinopathy.
Why is this ultrasound assessment so relevant, rather than relying only on the clinical exam?
Pain at the lower pole of the kneecap that worsens with activity points fairly clearly towards patellar tendinopathy, but the clinical picture alone doesn't tell us whether fibrillar degeneration, calcification or active neovascularisation predominates, nor does it reliably rule out other causes of anterior knee pain. Real-time musculoskeletal ultrasound with Doppler, done in the same consultation, provides exactly that information: what's happening in the tissue, exactly where the irritative focus is, and how it evolves over time. Without it, treatment is based on assumptions; with it, it's adjusted to what's actually happening in each footballer's tendon.
Frequently asked questions
Are tendinosis and tendinitis of the patellar tendon the same thing?
Strictly speaking, no: tendinitis implies active inflammation, while tendinosis describes a degenerated tendon without that classic inflammatory component. In practice, many chronic cases combine a degree of persistent inflammation with degenerative changes, which is why they're usually referred to together as patellar tendinopathy.
Can a footballer keep training if the ultrasound shows neovascularisation?
It depends on the degree of irritation and the specific load involved. In many cases part of the activity can be maintained by adapting volume and type of movement, rather than stopping completely; the decision is made individually in the clinic.
Do the blood vessels disappear with treatment?
In quite a few cases, the pathological vascularity decreases as the tendon moves towards a more stable phase, although timing varies from person to person and it doesn't always disappear completely.
When is a Doppler ultrasound recommended for a footballer with knee pain?
Above all when patellar tendon pain becomes chronic, doesn't respond as expected to initial treatment, or when it's necessary to clarify whether there's calcification or neovascularisation before deciding on an ultrasound-guided technique.
Article written by Chema, physiotherapist at KINEO Benidorm specialising in musculoskeletal ultrasound and invasive physiotherapy (EPTE).
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