Jumper’s knee also known as patella tendonitis, is a common injury among people involved in sports that involve lots if jumping and landing.
Sport specific biomechanics
Jumper's knee is believed to be caused by repetitive stress placed on the patella tendon – the tendon that connects the kneecap to the shin bone - or quadriceps tendon during jumping. It is a common injury in sportspeople, particularly those participating in jumping sports such as basketball, volleyball, or high or long jumping. Jumper's knee is occasionally found in football players, and in rare cases, it may be seen in athletes in non-jumping sports such as weight lifting and cycling.
Overtraining and playing on hard surfaces have been implicated as risk factors.
The patellar tendon experiences greater mechanical load during landing than during jumping, because of the muscle contraction of the quadriceps.
Symptoms of jumper's knee
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, although the patient is still able to perform satisfactorily in their sport
- Stage 3 - Prolonged pain during and after activity, with increasing difficulty in performing at a satisfactory level
- Stage 4 - Complete tendon tear requiring surgical repair
A physical examination may reveal the following findings:
- Tenderness of the patella (kneecap) or in the area between the patella and where the patella tendon attaches to the shin bone
- Hamstring and quadriceps tightness
- Normal ligamentous stability of the knee during testing
- Normal knee range of motion
- Normal neurovascular examination
- Normal hip and ankle examination
- Swelling due to fluid collection in the knee (rare)
Diagnosis of jumper's knee
- The diagnosis of jumper's knee is based on the history and clinical findings. Laboratory and imaging tests are rarely necessary.
- Laboratory studies are not indicated unless other potential causes, such as systemic, inflammatory, or metabolic disease, must be ruled out.
Treatment for jumper's knee
Most patients respond to a conservative management programme such as the one suggested below:
- Activity modification: Decrease activities that increase patellofemoral pressure (eg, jumping, squatting). Possibly initiate gentle eccentric loading activities.
- Cold therapy: Apply ice for 20-30 minutes - use a towel to stop the ice from touching the skin directly as this may cause a cold burn - four to six times per day, especially after activity.
- Joint motion and kinematics assessment: Evaluate hip, knee, and ankle joint range of motion.
- Stretching and strengthening exercises
- Anti-inflammatory medication
If the pain is refractory to these measures, options are limited. One can either abandon participation in jumping sports and/or consider surgery.
Tendon rupture requires surgical repair.
Knee immobilisation is contraindicated because it results in stiffness and may lead to muscle or joint contracture, further prolonging a sportsperson’s return to form.