Patellar Tendonitis (also known as Tendinopathy or the Jumper’s knee) is an overuse injury to the tendon that connects the patella to the tibia.
Tendons are strong fibrous cords that attach muscles to bones. The patellar tendon connects the bottom of the kneecap to the upper part of the shinbone in the area of tibial tuberosity and works with the muscles in the front of the thigh to straighten the leg and transfer the force of the quadriceps muscle. Quadriceps are controlling the bending of the leg and are involved in walking, jumping, etc. During jumping, the quadriceps muscles provide an explosive contraction, which straightens the knee and pushes you into the air. When landing, the quadriceps muscle helps to absorb the landing forces by allowing a small amount of controlled knee bend. Patellar tendon is involved in the process of jumping and can be injured due to the excessive pressure on the tendon. The damage to the tendon develops gradually. In the beginning the injury is tiny and is asymptomatic. As the lesion worsens the dysfunction of the tendon occurs and the affected person experiences pain. Patellar tendonitis is widely spread among the athletes.
Causes and risk factors
Another name of patella tendonitis is the jumper’s knee that refers to the main cause of the disorder – frequent jumping. Jumper’s knee in characterized by the damage to the tendon, although often there are no signs of the inflammation.
The athletes who are involved in basketball and volleyball, high and long jumping, tennis and gymnastics are more likely to develop the tendinopathy, although sometimes the disorder affects also not athletes.
In elderly the pattelar tendinopathy may develop as the result of degeneration due to the repetitive microdamage.
In some cases the traumatic patellar tendonitis may occur if the person experiences acute trauma to the tendon and don’t get adequate treatment to heal the tendon.
The common age of the affected persons is between 10 and 16 years.
Depending on the duration of symptoms, jumper’s knee can be classified into 1 of 4 stages:
- Stage 1 – Pain only after activity, without functional impairment
- Stage 2 – Pain during and after activity, the patient is still able to perform in his/her sport
- Stage 3 – Prolonged pain during and after activity, with increasing difficulty in performing at a satisfactory level
- Stage 4 – Complete tendon tear that requires surgical repair
The main symptom of the disease is the pain between the kneecap and the area of the shinbone where the tendon is attached.
An affected person experience:
- Anterior knee pain over the patella tendon at first present only as the person perfom physical activity or just after an intense workout;
- Pain worsens with jumping, landing or running activity and sometimes with prolonged sitting;
- Onset of pain is usually gradual and commonly related to an increase in sport activity;
- Bruising and cramping;
- Localised tenderness over the patella tendon and hamstring tightness;
- Often the tendon feels very stiff first thing in the morning;
- The affected tendon may appear thickened in comparison to the unaffected side;
- In the late stages the pain interferes with the everyday activities;
Typically, tendon injuries occur in three areas:
- musculotendinous junction (where the tendon joins the muscle);
- mid-tendon (non-insertional tendinopathy) caused by a cumulative microtrauma from repetitive overloading (overuse, overtraining);
- tendon insertion (into bone);
The diagnosis is based on the history of the disorder, physical examination. To estimate the pain the VISA pain questionnaire is used. X-ray examination of the knee is necessary if the other causes of the knee pain should be excluded. Ultrasound examination and MRI are highly sensitive methods of examination used to verify the diagnosis and evaluate the damage to the tendon.
To relieve the pain a child may use RICE therapy:
R – Rest the knee from the painful activity;
I – Ice over the affected area for 20 minutes every 2-4 hours, especially during the first 24-48 hours after any exercises;
C – Compress the painful area with an elastic bandage;
E – Elevate the leg.
As physical therapy during the recovery phase straight leg raises, short-arc quadriceps exercises and wall slides can be performed. Recommended efforts include exercises to improve the strength of the quadriceps, hamstring and gastrocnemius muscles.
Non-steroidal anti-inflammatory drugs are often used for pain and inflammation control (naproxen, ibuprofen and others).
Autologous blood injection, or platelet-rich plasma injection may be performed, such treatment is typically successful. Ultrasound or phonophoresis (ultrasound delivered medication) is helpful to decrease pain symptoms. Arch supports or orthotics are used to improve foot and leg stability and prevent future injury.
Surgery is indicated when the conservative therapy after 6-13 months fails to reduce the symptoms of tendinitis. A longitudinal or transverse incision is made over the patella tendon and abnormal tissue is then removed.