A Biomechanical Approach to OSD
The Truth behind Osgood Schlatter Disease
It is very common in young athletes to complain of knee pain. Many parents dismiss this as growing pains, or explain it away as a result of “hard training”. Sometimes however, the pain is severe enough that a visit to a doctor is in order. Many times the doctor will diagnose OSD, or Osgood Schlatter Disease. OSD is a condition involving the patellar tendon and its attachment to the lower leg bone.
What is OSD exactly?
A quick search on Google and a wide variety of discussion pops up regarding OSD. It is an easily identifiable issue with many suggestions regarding treatment. Many of those treatments will end in frustration and wasted money. This is true because these so called treatments are designed to address a symptom and not the causation. OSD in most respects is a symptom of a much larger issue. To understand the complexity of this problem, one must first understand OSD. A quick lesson in anatomy and physiology (the study of structure and function) will shed some light on OSD.
Simply, Osgood Schlatter Disease is defined by the American Academy of Orthopedic Surgeons as “an inflammation of the area just below the knee where the tendon from the kneecap (patellar tendon) attaches to the shinbone (tibia)”. Its medical diagnosis is “tibial tuberosity avulsion”. Also less frequently referred to as apophysitis of the tibial tubercle, or Lannelongue's disease.
More Anatomy and Physiology
For explanation purposes, the Tibia is the shin bone. A tuberosity is defined as a rounded prominence; especially a large prominence on a bone usually serving for the attachment of muscles or ligaments. Finally, an avulsion is an injury to the bone in a location where a tendon or ligament attaches to the bone. When an avulsion occurs, the tendon or ligament pulls off a piece of the bone. Quadriceps defined singularly, are comprised of four different muscles all inserting at the patellar tendon. The patellar tendon attaches to the tuberosity of the Tibia. The patellar tendon is also attached to the patella, the kneecap. The Quadriceps muscles are widely understood to create knee extension. This means as the Quadriceps contract, they will pull the knee from a bent position to an extended one. This creates a large amount of force at the point of insertion on the bone, in this case the Tibia. As this force creates too much tension, the tendon starts to pull off the bone. This is common in younger children because the exact point of insertion for the patellar tendon is also a growth plate on the bone. The growth plates are much softer than normal bone. With the combination of too much tension and a soft bone, tendons pull away. As the bone grows and ossifies (bone turning hard and rigid) a bump will form.
Symptoms of OSD
You will know you have OSD when the area beneath your kneecap is inflamed and painful. Over time the bump will become hard and permanent. In most cases, OSD will need to be diagnosed by your doctor, although the symptoms are not hard to identify. OSD can come with a variety of other symptoms as well. “Intense knee pain is usually the presenting symptom that occurs during activities such as running, jumping, squatting, and especially ascending or descending stairs and during kneeling. The pain is worse with acute knee impact. The pain can be reproduced by extending the knee against resistance, stressing the quadriceps, or striking the knee. Pain is initially mild and intermittent. In the acute phase, the pain is severe and continuous in nature. Impact of the affected area can be very painful”.
Why OSD is a symptom of a larger issue?
Again, doing a Google search will result in a wide range of treatments, none of which are addressing the cause of OSD. In the medical industry it is often necessary to treat symptoms before causative factors. This is important, but doing that and never addressing the source of pain is an exercise in futility. OSD is not a side effect of growth and those unlucky enough to suffer from it need not too. Patellar bands, knee braces, and anti-inflammatory medication may be temporary solutions but will never resolve the underlying issue. Understanding the balance between compressive and tensile force is key to understanding OSD.
Let’s take the next logical step.
Growth should not be painful. Pain is an indicator that something is wrong and shouldn’t be ignored. What does this mean for OSD? It means there is a problem, and when resolved knee pain will disappear. The truth is OSD is a result of two major factors. It is a symptom of accumulated trauma and poor biomechanics.
Joint movement is always comprised of a set of muscles relaxing while another sets contract. Muscles also stabilize joints. Ligaments are responsible for joint integrity, but muscles are responsible for joint stability. The relaxing muscles do not completely relax in joint movement. If they did, the joint would lose stability and injury would occur. When considering the knee and OSD, very little attention is given to the Hamstrings. The Hamstrings are the muscles at the back of the leg. They are often associated with the opposite action of the Quadriceps. This is true, but an overly simple explanation of their function. In most cases of OSD, ham dysfunction is present and never identified. The hamstrings play an important role in knee stability. They reduce sheer force on the knee. Sheer force is the act of the lower leg sliding forward from the upper leg during extension. Sheer force is a big problem with ACL injury as well. In previous articles I have indicated that some knee pain is a big precursor to ACL injury. This is why. What’s more is the prevalence of meniscus injury, the ligament that acts as a shock absorber within the knee. Often poor Hamstring function is related to meniscal damage. As we look at the knee as a whole it becomes evident that OSD is symptomatic of much larger problems. When those problems are not fully resolved, higher risk factors for injury are unavoidable.
Accumulated trauma, due to poor mechanics, creates anatomical adaptations. It is that adaptation that becomes painful. Too much force is applied to too small an area. This concept accounts for many injuries in children but OSD is especially relevant. Pain occurs when the functional capacity the system is exceeded and no other compensation is available. Osgood Schlatter is very real but only a result of more insidious problems. It is true that most children will grow out of OSD, but many will bear the scars of a painful adolescence. What they will not grow out of, are the poor mechanics that caused those scars. This puts these children at higher risk of more significant injury later in life.
Fixing the problem.
If you or your child suffers from OSD, stop addressing symptoms and start addressing causation. Movement literacy is the first place to start, followed by a realistic plan regarding exercise load. That load can, at first, be a moving target. With poor biomechanics, very little load will produce pain. Fix the mechanics and watch the pain slowly dissipate. But do this without managing work load and all you train is poor mechanics. It takes a big step to “step back” from sport to fix larger problems, but is well worth it down the road. Functional biomechanics will produce much higher resistance to load later in life. If parents are patient and have long term goals for their children, this becomes an easy decision. At Performance Pediatrics at HPR, we address OSD all the time. We have found that a few weeks off with highly effective movement retraining solves in upwards of 90% of Osgood Schlatter problems. It also often increases sport performance.
All the practitioners at Performance Pediatrics and Human Performance and Rehabilitation are willing to help in any way. If you have questions, or would like to speak with a professional please feel free to call, we do the best we can to make time for parents and aim to educate whenever we can. We can be reached at:
402 West Garden of the God’s Road
Colorado Springs, CO 80907