Jumper’s Knee / Osgood Schlatters
Jumper’s Knee or patellar tendonitis is traditionally thought to be caused by overuse or injury to the patellar (knee) tendon.
If the patella tendon is chronically irritated it can cause a prominence to develop at the point where it inserts into the bone. This is referred to as Osgood Schlatters Disease which affects 1 in 10 adolescents.
In adolescents the patella tendon can be stronger than the unfused bone it inserts into and therefore it can become overloaded from sporting activity. Once the tendon is chronically overloaded then it becomes load intolerant.
More recent research comparing the the level of physical activity of adolescent males with patella tendon pain with an asymptomatic group found that physical activity was similar in both groups. This brings into question the overactivity hypothesis of patella tendon pain. Differences in landing mechanics were evident, however, between those with tendon pain and those without. Movement quality may therefore play a role in the development of the condition.
Patella Tendon Anatomy
The patellar ligament (also called the patella tendon) is a large strong ligament that runs from the top of the kneecap (patella) & runs down over the kneecap to insert into the top of the shin bone. The patella tendon is a continuation of the the quadriceps muscle that runs along the front of the thigh.
What is Jumper’s Knee / Osgood Schlatters?
Jumper’s Knee or Osgood Schlatters is relatively common in teenagers who are very active in sports. It is most common during the Summer months in Ireland when the ground hardens & the load transferred to the knee tendon increases. This overuse syndrome causes inflammation of the insertion of the patellar tendon on the top of the shin bone. It can cause a painful bump just below the knee.
Recurring tractioning of the tendon due to repetitive jumping or running leads to repetitive microtrauma of the bone. As a result the bone often grows in size and can be felt as a lump below the kneecap.
In sitting, if you place three fingertips below the kneecap then the lower finger will normally touch this bony ridge where the tendon inserts. If the bone on the affected knee is much bigger than the good knee then this is an indication of possible Osgood Schlatters.
Symptoms of Jumper’s knee / Osgood Schlatters
Osgood Schlatters normally presents as a painful lump under the knee cap of teenage boys. You may notice that the bone is more prominent than the less painful knee. The pain in the knee may get worse after sport & ease when you start running.
As the condition progresses, pain may come on while running & eventually will last between training sessions. At this stage, playing sport will become difficult. This is often where the young athlete begins to seek physiotherapy advice.
For some, with milder irritation of the tendon, as with Jumper’s Knee, the pain is relatively mild. In other cases where the bone is affected to a greater degree, the pain is more extreme and long-lasting. In most cases of tendon pain, the pain is present in one knee only or, if both sides, it is generally a lot worse on one side.
Symptoms related to Osgood-Schlatter have been reported to last up to 2 years in many cases, indicating the importance of education and long-term management strategies. The pain may last until the athlete is finished their growth.
Causes of Osgood Schlatters
Osgood Schlatters is an overload of the patella tendon (patella ligament). The combination of overload & rapid growth of bone combines to overload the extending patella tendon. The patella tendon is under greatest pressure during jumping & sprinting activities & so it is most commonly seen in sports such as basketball & soccer.
Treatment of Jumper’s Knee / Osgood Schlatters
The first step in addressing Jumper’s Knee is activity modification. This requires an analysis of the current activity levels & a reduction of total load to minimise knee pain & swelling. In most cases a reduction in sprinting & jumping activities is required. Physiotherapy interventions will look at addressing tightness & poor muscle control around the trunk and legs.
Rehabilitation of the lower limb muscles along with specific exercises to address movement patterns that may be creating overload at the knee joint is vital. This requires a specifically tailored rehabilitation programme based on analysis of the athlete & identification of potential flaws in their movement patterns.
The difficult part is cutting back on activities that cause the symptoms. Continuing to load a knee that is already irritated & painful will only make symptoms worse & may require a more prolonged period of rest in order to settle down.
What does the research show regarding recovery time?
In one study, 16% of participants were able to return to sport at 3 months. This increased to 67% at 6 months. However, at one-year follow up, 43% of participants said they would not be satisfied to continue to live with their current symptoms. This shows the long-term pattern of Osgood Schlatter’s disease and the importance of early intervention to avoid long-term worsening of the condition.
• Jumper’s Knee or Osgood Schlatters is an overuse injury that occurs in children & teenagers undergoing heavy training during a growth spurt
• It gives rise to pain at the front of the knee & is often associated with a noticeable lump underneath the kneecap
• Osgood Schlatters has a long-term prognosis and activity modification may be required in the medium to long-term to manage symptoms
• Complete rest should be avoided at all costs as it leads to further weakening of the knee and is associated with much longer timelines in returning to sport
• Jumper’s Knee and Osgood-Schlatter can be successfully treated by physiotherapy interventions along with specific exercises & activity modification.
Pietrosimone L, Blackburn J, Wikstrom E, Berkoff D, Docking S, Cook J and Padua D (2020) Landing Biomechanics, But Not Physical Activity, Differ in Young Male Athletes With and Without Patellar Tendinopathy. Journal of Orthopaedic & Sports Physical Therapy, 50(3), 158-166. https://pubmed.ncbi.nlm.nih.gov/31905096/
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