Jumper's Knee is a common complaint amongst runners and can cause much pain and discomfort. Here's how to recognise the symptoms, the treatment required and the steps to recovery.
The Running Injury Bulletin - Jumper's Knee
Jumper's Knee - Knee pain whilst and after running.
This month’s injury is one seen to a high degree in explosive running and jumping sports and is often referred to as ‘Jumpers Knee’.
Jumpers Knee is the common term for Patella Tendonitis, and occurs gradually as a result of repeated jumping and landing based training. Repeated strain on the Patella Tendon leads to a greater degree of breakdown in the tendon structure, and may result in swelling.
Patella Tendonitis is however quite a rare problem, with a lesser known condition called Patella Tendinopathy being the more likely culprit. This article will attempt to explain the difference between these conditions and offer methods to prevent or manage patella tendinopathy.
Where is the Patella Tendon?
The patellar tendon is the structure lying below the patella (kneecap), attaching the quadriceps muscle to the tibia (shin bone). As the quadriceps muscle contracts and shortens it is the attachment of the patella tendon that allows the knee to extend (straighten).
The Patella Tendon
Signs and symptoms
In the early stages of patellar tendinopathy the most common symptom is tenderness over the lower edge of the patella. Tenderness here is more usually felt after exercise and it may be uncomfortable to squat or kneel.
As the problem worsens pain may be felt during training, eventually becoming constant and experienced even at rest. A professional opinion should be sought well before this stage otherwise your training may be affected for a long period of time. A suitably experienced Physiotherapist will assist you in effective rehabilitation.
Very little inflammation if any occurs in the tendon, with many studies showing degenerative changes in the tendon rather than any clear inflammatory process. This is therefore a tendinopathy as opposed to a tendonitis (‘itis’ = inflammation). Anti-inflammatory medication such as ibuprofen may therefore have little effect on the problem, other than contribute to the relief of pain.
Causes
Patellar tendon pain can occur from a number of different forms of training, but as the term ‘jumper’s knee’ suggests it is mostly the result of rapid and repeated deceleration forces. In runners this may involve downhill running or running over rough terrain.
A potential cause of patella tendinopathy may include weak quadriceps muscles in comparison with hamstring strength leading to increased shearing forces on the patellar tendon. Poor eccentric control of the quadriceps and patellar tendon may lead to increased strain through the tendon following downhill running or exercises such as squatting or lunging.
Another causative factor is mechanical impingement of the tendon. This involves pinching of the back part of the tendon between the patella and the thigh bone (femur) whilst the knee is bent (flexed). In this instance, tight quadriceps will worsen the mechanical problem by drawing up the patella higher on the femur during knee flexion.
Diagnosis
The diagnosis of a patellar tendinopathy isn’t difficult. Usually the upper part of the tendon is tender and in long-term (chronic) cases there may be thickening of the tendon.
Swelling may indicate pinching of other structures, such as the cushioning fat pad. There may be some wasting of the quadriceps muscle as the pain inhibits the firing of these muscles, although the wasting may be a causative factor (see above).
Management
There is nothing to be gained by doing exercise that increases discomfort levels in the patella tendon. Any activity that produces a rise in discomfort, for example from 3/10 to 6/10 should be stopped.
As this injury has no inflammatory component, it is illogical to use non-steroidal anti-inflammatory medication, such as ibuprofen.
Pro-inflammatory treatments such as ultrasound may also be limited in effectiveness, but may help stimulate collagen-forming cell activity and stimulate the formation of new blood vessels in the area.
Assess hip extension and quadriceps flexibility as these will affect the pinching of the patella tendon. Controlled lunging and step-down tests may give an indication of the eccentric control of the knee and the forces through the tendon.
If this causes pain on the affected side, compare with the non-affected side to check that this is not normal for you. Exercises to regain strength, stability and proprioception (knowing where body parts are without looking!) will lead to long-term improvements in this condition.
It is also important to assess trunk stability and hip control.
Eccentric exercises
Eccentric exercise drills appear to be the best way of promoting tendon remodelling (re-growth and reordering of collagen tissue).
These exercises may include single or double leg balance squats, step-downs, or lunges, with the emphasis on the lowering part of the activity. Keep the knee aligned with the hip and foot. Just nudge the discomfort then return to the start position. Again a suitably experienced physiotherapist can devise a tailored program and demonstrate these exercises.
The rate of progression will vary from athlete to athlete, dependent in large part on how often they perform the exercises. If more pain occurs in the tendon rest for two to three days and then drop back one stage with your exercise progression.
Other rehabilitation considerations
Alongside the eccentric exercises, address other possible contributory factors, such as
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Quadriceps and hip flexor tightness
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Hip, knee, and ankle range of movement
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Training shoe support
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Stiffness in the lumbar spine
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Discrepancies in leg length
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Poor technique
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Over-training
Prevention
There is little conclusive evidence on predisposing factors of patellar tendinopathy. Use controlled progressive plyometric drills and lunging techniques, and check regularly for knee symptoms. Regular hip and quadriceps stretching routines may be helpful.
For any coaches out there, it would be interesting to see if controlled eccentric drills in routine training reduce the incidence of patellar tendinopathy in athletes without symptoms.
To recap, the following signs & symptoms may be suggestive of patella tendinopathy:
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Pain at the lower end of the knee cap that comes on gradually.
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The pain is worsened by activity.
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Patella tendon is painful to touch.
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Patella tendon feels stiff first thing in the morning.
Until next time, happy and healthy running. Enjoy the Summer!
Ross Clifford MCSP is a practising Physiotherapist with a specialist interest in sport and exercise Physiotherapy. He also holds a Sports Science degree and has taught in the area of Sports Injuries and the Biological Sciences. He is a keen runner and cyclist.
Ross in action
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