The tendons above or below the kneecap (patella) can become inflamed, as well as the tendons on the sides of the knee joint. Tendons are the extension of the muscle and attaches the muscle to the bone. These tendons are mainly responsible to transfer the contraction of the muscle to the bone, mainly to anchor the muscle & provide a axis of movement. Knee Tendinitis typically occurs due to repetitive running, jumping, hopping, squatting or kicking activities. Its also particularly common in sports that require frequent jumping and landing resulting in an overload on the knee tendons.

When these forces are too much for the tendon to handle, it starts tearing the fibers. The muscles act like a motor that pulls on the tendon, which acts like a cable on a pulley, to move the joint. If the force through the motors are too much, the cable will start to tear and break apart. So the cable (tendons) must be able to withstand the force of the motors (muscles) when it contracts (during concentric contraction – shortening of the muscle).

Each person’s case is unique and we want to address your specific needs. If you would like us to investigate or provide some insight, we invite you to contact us by clicking the link below.

Muscles & Tendons in your knee

In the front of your knee you have four muscles of the quadriceps that converge to form the Supra-patellar tendon (‘Supra’ meaning above), weaving around the patella to anchor onto the front of your shin, as it passes to the front we refer to the tendon as the infra-patellar tendon (‘infra’ meaning below). At the back of the knee we have the hamstrings, two tendons running around the inside (Semi-membranous & Semi-tendinous) and one on the outside (Bicep femoris tendon).

There are smaller tendons that run along the same areas, but we’ll discuss them at a later stage.12

Tendons are like cables

The cables (tendons) must be able to withstand the pulling force when its suddenly loaded, like when a car is being towed, the cable must be strong enough to absorb the force when the car is suddenly pulled forward. If the towing car just accelerate, without taking up the slack, the cable will not be able to withstand the force and tear. This is what happens when we land from a jump to control our decent. This type of loading is called eccentric loading of the tendons (the muscle contract, but lengthens).

A tendinitis happens then we constantly repeat the same movement, and the load on the tendons are too much for it to handle. This overload, and overuse cause small tears inside the tendon. Our body tries to heal itself but you keep on overloading it, causing the cycle to continue.

How your body tries to heal itself

Your body tries to heal the injured tendon by sending inflammatory cells to clean up and repair the torn fibers. This process only starts after you have finished the damage causing activity, thus your pain will be more prominent after the activity than, during it. When these inflammatory cells infiltrate the tendon, they cause swelling. In some cases, if the damage has been going on for more than a week, the swelling tends to get less.

When your body starts re-attaching the small tears in the tendon you will feel a very distinctive stiffness, especially in the mornings, due to the fact that at night your body can spend time healing the injured tissue. If you start that same overloading movement the next day, you tear open the repaired tissue, and the damage to the tendon continues…

Knee Tendinitis vs Knee Tendinosis

These are three technical therms that we use to disgusting between the state of the tendon’s damage.

  1. Tendinitis is inflammation or irritation of the tendon, that is in the early phases.
  2. Tendinosis is when the healing of the tendon stops, but the damage is continued.
  3. Tendinopathy is the state of the tendon when its deteriorating and degenerating.

Which tendon is painful?

Supra patella tendinitis

This involves the quadriceps muscles and is mostly referred to as a Quadriceps tendinitis. The tendon stretches from about 4 fingers above the kneecap to attach onto the top rim of the patella. Its common in cycling sports, rowing and horse riding due to the fact that your knee remains in a bent position and rarely goes through the full range of knee movement. The knee is kept at a certain angle and only trained here, which leads to the tendon being vulnerable when moving out of this range.

Patella tendinitis or infra-patella tendinitis

A very thick tendon that connects to the bottom rim of the patella and attaches approximately 3 fingers below the knee cap on the front our shin bone. Its more common in runners (hens the name runner’s knee), dancers, long-jumpers, due to the sudden loading of the tendon while the knee is flexed. This tendon has to control the decent during a landing, it must decelerate the force to control your knee movement.

When the load placed on the tendon is in excess of what the tendon is able to withstand, the tendon will split and tear. Imagine jumping off a step and landing on one leg. Now repeat, but holding a 10kg weight… The load that must be absorbed by the tendon is exponentially more.

Semitendinosus and Semimembranosus Hamstring tendinitis (back & inside)

Two of the three hamstring tendons that attach on the inside of the knee. Its more common in Cyclist with a very hard back stroke, due to the tendon being put under repetitive load when the hamstrings are contracted. Also in Golfers, where the right side is the supporting leg these tendons must withstand the force of the knee torsion(turning) when a stroke is played.

Bicep femoris tendinitis (back & outside)

This involves the stronger one of the three hamstring tendons that attach on the outside of the knee. Its more common in tennis, squash players that accelerate and decelerate at high speeds, combined with the strain put on these tendons to stabilize the knee in all these positions.

What does a knee tendinitis feel like?

The pain develops gradually over a few weeks with on specific incident that you hurt it, or fell on it. The pain is there when you are doing the activity (running), and even worse 30 minutes after you’ve stopped. One unique feature of a tendinitis is stiffness. Stiffness, especially in the morning, or then you were in a resting state (sitting down after a run). When you get up, you’ll feel stiffness over your knee and you will feel like you have to stretch it out to relieve it. DON’T!

Another feature of a tendinitis is that the pain goes away when you warm up for training, or then you are at the start of your training. This is only at the beginning of a tendinitis, later the pain will not ease up during training, and will become more intense. The pain after training takes longer to go away (2 hours instead of 20 minutes). Even walking, climbing stairs and standing will be enough to bring on the pain.

Patients usually complain of the pain as being a 3/10, more a niggle or discomfort, rather than ‘pain’. They report that their main concern is the knee feeling unstable and weak when they want to use it, land, run downhill, etc.

Scans and Diagnostic tests

Physiotherapist can accurately diagnose a tendinitis by stressing the individual structures. In some cases, then the tendon irritation and inflammation doesn’t seem to improve our Physio will refer you for a Sonar or Diagnostic Ultrasound.

Sonar or Diagnostic Ultrasound will be very precise and show a tendinitis. This is helpful to pick up any other problems that could cause the irritation on the tendon. The radiologist may also indicate the stage of degeneration as well as distinguish between a tendinits, tendinosis and tendinopathy. This will be the best course of action to identify or exclude any tendon involvement. Tendons are soft tissue and will not show up on X-rays. In some cases MRI or CT-scan can be taken, but a bit of an overkill.

Recovery time: Knee Tendinitis – Tendonitis – Tendinopathy

To determine how long the recovery process might take, we need to take into account the state of the tendon and how long this repetitive damage cycle has been going on. Some patient wait up to a year before seeking help, so keep this in mind if you decide to ‘just walk it off’. The pain will become less, but it’ll linger never really going away.

Knee Tendinitis – approximately 6 weeks
Knee Tendinopathy – approximately 8 – 12 weeks

Remember that every case is different and that there are a lot of factors that must be assessed in order for the healing to take place and return it back to its normal state. Most of all we want to prevent it from coming back again.

What makes a knee tendinitis worse

  • Squats
  • Jumping Lunges
  • Hill runs (up & down)
  • Stair climbing
  • Any form of jumping

Other problems that influences a tendinitis

  • Muscle length of the muscles that attach to the affected tendon. These muscles must be guided through a program to regain their normal length.
  • Muscle strength – Eccentric loading of the affected muscle groups
  • Abnormal loading – Movement pattern assessment where the forces converge long a certain line, put too much strain over a certain aspcet of the tendon, rather than spreading the load evenly.
  • Rotation – causes rotational torsion on the tendon

Also known as
Knee tendinitis, knee tendonitis, knee tendinopathy, Quadriceps tendinitis, Quad tendinitis