Jumper’s knee, also known as patellar tendonitis, is a condition characterized by inflammation of your patellar tendon. It is a chronic, painful, degenerative overload disease of the patella extensor apparatus at the bone-/tendon junction of the patella tip.
The kneecap (patella) is located as a sesamoid bone between the upper and lower leg at the front of the knee joint. It is part of the knee joint. It has a triangular shape, with the base of the triangle facing the thigh and the tip facing the lower leg. The extensor muscles of the thigh (Musculus quadriceps, quadriceps muscle) end sinewy at the base of the kneecap. The patellar tendon runs from the tip of the patella to the front of the lower leg (tibial tuberosity). In this way (quadriceps muscle – quadriceps tendon – patella – patellar tendon – tibiae), the force development of the thigh extensor muscles is transferred to the lower leg.
The patellar tendon is exposed to particularly high loads during jumping because this causes a strong and jerky tensile stress on the tendon. This can overload the tendon tissue.
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In everyday clinical practice, there is usually no classification of patellar tip syndrome.
The most frequently mentioned classification is that of Roels et al. 1978:
- Grade I: Pain after completion of exertion
- Grade II: Pain at the beginning of the load which disappears after the warm-up period and reoccurs after the end.
- Grade III: Permanent pain
- Grade IV: Patellar tendon rupture (tear of the tendon)
Causes of the jumper`s knee
The patellar tendon syndrome/jumper’s knee represents a clinical picture which is caused by overloading of the patellar tendon through repeated, unaccustomed and/or violent tensile stress.
There are both external factors that can cause patellar tendon syndrome/jumper’s knee, as well as internal factors.
One of the external influencing factors is the activity causing the complaint. Since a maximum tensile stress on the patellar tendon occurs particularly in jumping sports, sports such as volleyball, basketball, long jump or high jump are frequent triggers for patellar tendon syndrome/jumper’s knee. Therefore the disease is also called jumper’s knee. The frequency of the load, the intensity of the load and the unfamiliarity of the load (new sport, beginners) play an important role in the development of a patellar tendon syndrome.
But also in cycling, weight lifting, jogging on hard surfaces, tennis, a patellar tendon syndrome/jumper’s knee if found more often.
One of the internal influencing factors is:
- the age (mostly patients over 15 years)
- a knee-cap high (patella alta),
- a history of Osgood-Schlatter’s disease
- a reduced extensibility of the leg muscles
- and a congenital ligament weakness (ligament laxity)
The structural damage in a jumper knee concerns the tendon/bone transition of the patellar tendon (patella) at the tip of the patella. Microscopic examinations have revealed significant degenerative (wear-related) changes in the tendon tissue, whereas inflammatory cells were missing. This is therefore a degenerative (wear-related), not an inflammatory disease.
Symptoms of the jumper`s knee
Patients with patellar tip syndrome report load-dependent pain in the area of the patella tip. Depending on the stage of the disease, the pain may be present at the beginning of the load and disappear again after the warm-up phase, while it reoccurs in the phase after the load. In the advanced stage, the pain remains throughout the entire load. In very advanced cases, the patella insertion hurts not only during sporting activities but also permanently in everyday life, for example when climbing stairs. Some patients describe a stab-like pain at certain angular conditions of the knee joint under load.
Typical is the persistent character of the complaint pattern. It is often a chronic disease pattern that lasts for many months to years with phases of low symptoms, but recurring symptoms after peak loads.
Patellar tip syndrome occurs in 20-30 percent of cases on both sides.
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Diagnosis of the jumper`s knee
The medical history (anamnesis) of patients with jumping sports as hobbies is trend-setting. Frequent jogging on hard ground or bodybuilding is also mentioned more often.
During the physical examination, a pressure pain above the tip of the patella is usually noticeable. A painful stretching movement of the lower leg against resistance is also typical. Visible redness or swelling are less common signs. Sometimes the knee joint is also completely unremarkable, in which case a suspected diagnosis can only be made on the basis of the patient’s medical history. Some patients also complain of a feeling of stiffness and pain after sitting for a long time, e.g. after long car journeys.
Sonography (ultrasound) is an easily available and suitable procedure for the diagnosis of a Springer knee. In order to be able to assess any changes correctly, the healthy opposite side should always be examined as well. Typical sonographic changes in a jumper’s knee are tendon thickening, irregularly limited tendon gliding tissue and an irregular tendon structure.
MRI examination of the knee is not part of the routine diagnosis of patellar tendinitis / jumper’s knee, even if it is a suitable procedure.
MRI is of importance for the localization of the degeneration area when surgical removal of the altered tendon tissue is pending. In addition, MRI of the knee allows the quality of the patella tendon to be assessed better than with sonography.
Further information on this topic is also available at MRI examination of the knee
X-rays do not help with patellar tip syndrome/jumper’s knee and are used to exclude other diseases.
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MRI for Patellar Tip Syndrome
Imaging techniques play an important role in the reliable diagnosis of patellar tip syndrome.
The main focus is on x-rays and sonography, through which changes in bone and patellar tendon become clearly visible.
In contrast to them, magnetic resonance imaging (MRI) is not part of the routine examinations of the jumper’s knee and is therefore rarely used in this case.
The greatest advantage of this imaging technique is that it allows a very precise localization of the degenerated area, which is why it is used especially in the context of surgical removal of the affected tissue. In addition, the MRI allows the exclusion of differential diagnoses, such as degenerative changes in the cartilage, for example knee arthrosis.
Therapy for the jumper`s knee
For some years now, taping has been increasingly finding its way into various areas of medicine. Especially in sports medicine and physiotherapy, the technique is becoming more and more popular and is used in the prophylaxis and treatment of various diseases.
Depending on the technique used and the tape itself (the color of the tape also plays a role), the tape should have different effects on the target organ. Although many doctors and physiotherapists swear by the tape, it should be emphasized that its effect has not been scientifically proven to date.
Kinesiological tape is also widely used in the therapy of patellar tip syndrome. It is mainly used for prophylaxis of the disease as soon as the first signs of the syndrome appear.
The so-called patella tendon tapes and patella bandages (jumper knee straps) are intended to prevent long rest periods in sports.
In the case of pronounced complaints, however, a longer period of absence from sport cannot be avoided even with tape. Furthermore, taping should enable a faster return to sport after a long break due to patellar tendinitis. In both cases it has the function of absorbing tensile forces on the tendon and instead of transferring them to the skin on which it has been applied tightly.
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Shockwave therapy of the jumper`s knee
Patellar tip syndrome is usually treated conservatively, i.e. non-surgically. In addition to various medications, physiotherapeutic and physical measures are mainly used. These include massages, cold and heat therapy and high-energy extracorporeal shock wave therapy. The target organ, in this case, the knee, rests on a plastic cushion filled with water, into which sound waves are introduced. These are bundled at the target location, i.e. the affected tissue of the patella tendon.
Shock wave therapy is used for various diseases, with the main focus being on calcifications and ossifications.
A therapy session takes about two to five minutes and can be performed on an outpatient basis.
In the case of patellar tip syndrome, as well as in the case of other consequential damage caused by overload, the best therapy is good prophylaxis.
Warming up before sport, a slow increase in load and sufficiently long breaks between training sessions play an important role here. However, muscle stretching is also important to prevent patellar tendinitis. Special attention should be paid to the front thigh muscles, especially the quadriceps femoris muscle (the largest thigh muscle). For this purpose, a series of simple exercises are available, which should be performed especially after training.
In addition to prophylaxis, stretching exercises are also suitable to support the healing of an already existing patellar tendon syndrome. For this purpose, the exercises should be performed several times a day for a few minutes at low intensity. However, it is important not to overload the tendon.
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In some cases, despite a consistent break from training and correct conservative therapy, no satisfactory result is achieved. In these cases surgical therapy remains the only possibility to restore the Sports ability and Freedom of complaint.
There are various options for the surgical treatment of patellar tip syndrome. On the one hand, the tendon gliding tissue can be removed in order to remove the disturbing tissue.
The area around the tendons is cleared so that no disturbing cartilage or inflammatory signs rub against the tendons. In addition, the tendon at the tip of the patella can be loosened. This reduces the tension of the tendon on the patella and thus improves the symptoms. In some cases, the tendons can be incised lengthwise using a laser. This also reduces the tension of the tendons on the patella.
All these procedures can be performed minimally invasive, arthroscopic. In addition, each procedure can be individually, but also in
combination can be applied.
Which method is used depends on the extent of the tendon change, and in order to determine the surgical procedure, a magnetic resonance examination (MRI) is essential before the operation. If the change is only present at the tendon insertion, minimally invasive therapy using arthroscopy is recommended. In this case, the tendon can be partially detached and the altered part of the tendon removed.
In the case of a more severe or longer-distance tendon damage or partial necrosis of the tendon, open surgery is often necessary.
Here, the surgeon must decide individually which surgical procedure to use and how much tendon tissue to remove.
A post-operative treatment phase should always follow the operation. What exactly this phase looks like must be decided individually. This depends on the findings and the operation performed.
The following phases can be mentioned as an orientation:
- For the first 3-5 days after the operation, the knee should be relieved with crutches.
- This is followed by light physiotherapy for about 2-6 weeks, which is slowly intensified by strength and coordination exercises.
- Approximately 2-6 weeks after the operation, a light exercise on the bicycle ergometer can be started.
- The first light running exercises can be started after 4-8 weeks and then slowly increased individually.
- After approx. 4- 8 weeks the first strength exercises can be carried out,
- Jump training should only be started after 6 weeks – 4 months.
On average, depending on the findings, full athletic ability can be achieved after 2 to 6 months.
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Healing of a patellar tendon syndrome
Since patellar tip syndrome is a disease that occurs, among other things, due to excessive or prolonged stress, healing depends on consistent therapy and often also an initial consistent relief. There is no single effective therapy to cure patellar tip syndrome. The therapy is composed of different components, which consist
- Targeted strengthening exercises
Prognosis of the jumper`s knee
A conservative therapy is promising in most cases if a sufficient period of sports leave is observed. Tape bandages and relieving orthoses as well as a soft shoe sole can sometimes prevent recurrences or diseases.
The success rate after operative therapy is stated in the literature as 70-90% of good and very good results. Often, however, the sport-specific return takes place at a lower sporting level.
If the patellar tip syndrome occurs for the first time, the strain should be significantly reduced, in some cases even completely absent for a few days. In this way, the inflammation that has developed in the knee joint can heal. In some cases, this is initially sufficient to relieve the symptoms.
Physiotherapeutic treatment in the acute phase is carried out using heat and cold applications and ultrasound. Later, special stabilization and strengthening exercises are used to strengthen the tendons of the knee. Wearing a special knee bandage can also significantly help to reduce pain and promote healing.
In rare cases, the patellar tendon syndrome cannot be cured conservatively. In such cases, surgery is indicated, which in 70-90% of patients will lead to full athletic ability again after about 2 to 6 months. However, the best therapy is prophylaxis.
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Stretching exercises before and after sport
Furthermore, sporting activities should not be increased too quickly, so that the knee is not overloaded. A sufficient break between sports activities is also important to give the knee enough time to regenerate.
In case of a malposition of the leg, in the sense of O- or X- legs, special insoles can prevent a patellar toe syndrome. All these prophylactic measures also apply if a patellar tendon syndrome has existed and there are no or minor complaints. In this way a recurrence of patellar tendon syndrome can be avoided.
An exact period of time for patellar tip syndrome cannot be given. This depends on the extent of the tendon changes and the consistent implementation of adequate therapy and the right exercises.
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