One of my best sources for recent literature is via a good friend of mine, Mr Jonny King (@Jonny_King_PT). Before he shot off to Doha to have his moment in the sun, he left a multitude of articles on my desk for me to read, one of which was a study looking at that persistent pest in my clinic, Osgoods Schlatters Disease (OSD).
OSD falls under the apophysitis or enthesopathy umbrella along with severs disease and Sinding Larsen Johansen disease amongst others. In our injury audit for the last season, these injuries alone accounted for 20% of our total injuries (u9-18s).
However, with a little bit of education to players, parents and coaches we feel confident that we can manage these numbers even better.
We are very lucky to be part of an in depth, ongoing study with the brilliant and very knowledgable Jenny Strickland at the University of Greenwich. With her guidance and protocol, we are bringing the days spent on the treatment table down considerably, but ideally we want to learn about these conditions to help prevent them in the first place.
What do we think we know?
OSD is a growth related condition, we think it can be attributed to high levels of activity during periods of growth. Unlike an adult presentation of a tendinosis, the condition affects the soft cartilaginous junction between the patella tendon and the immature anterior tibial tuberosity (ATT). (See my previous blog for the BJSM about differences between adult and Paeds injury management here).
Demonstrating the close relationship between the enthesis, the patella tendon, the infra patella fat pad and the physis of the tibia.
Historically OSD has been labelled as “growing pains” (a genuine medical entity, but no clinical similarities to OSD) and sufferers of the condition may well have been told to “just get on with it” or that “you’ll grow out of it”. Unfortunately this attitude still exists amongst some parents and, regrettably, GP’s – we see first hand evidence of this in our academy. When I first started in my role, I was guilty of just sitting a lad on the plinth with some ice, telling him to rest for a few weeks and we’ll see how we go.
OSD can almost certainly be attributed to growth spurts, where high levels of cellular activity in the growth zones of bone can’t be matched by the attaching muscles, resulting in traction on the inherently weak enthesis. Usual subjective presentation is that of an ache during, or more prominently, after activity. Gradually pain has been worsening over a period of days or weeks. Eases with rest. However, occasionally we see examples of players that have been kicked or landed on their knees in acute incidents but will display all the characteristics of OSD. But this doesn’t fit with our understanding of growth and traction…
Sailly et al (2013) looked at symptomatic adolescent male athletes competing in elite sport and using Doppler ultrasound they compared the ATT complex to gauge different stages of maturation. Within these stages of maturation, they could attribute pain scores from symptomatic athletes to determine the more vulnerable stages of growth (figure 2 below). The best descriptions for these stages that I have heard are from Sid Ahamed on his Adolescent Injuries course. He describes the enthesis as a continuum that develops with maturation from a stable state to an increasingly unstable state as the cartilage calcified with age.
Classification system of the maturation status of the ATT from stages 1 to 4. ATT, anterior tibial tuberosity; B, bursa; FP, fat pad; HC, hyaline cartilage; M, metaphysic; O, ossicle; P, physis; PT, patellar.
In Sailly’s study they found that no players reported pain during the “stable” first phase but increasing scores of VAS in stage 2. As the enthesis calcified and unites in stage 3 and 4, the numbers decrease again.
So what is happening in this 2nd stage of maturation? The use of Doppler ultrasound opens some new theories. In these symptomatic stage 2 patients, there was Doppler activity within the pre-patella and deep infra patella bursa, indicating the presence of neo-vessels within these structures. Recently, Seth O’Neil (physio matters podcast) explained that most of these pain inducing neovascular structures are actually present in peritendon & surrounding tissues like the bursa, fat pads and fascia. Maybe the same is true with the adolescent population.
The synovium that surrounds the enthesis is highly prone to compressive forces and as such, prone to inflammation. In the developing ATT, the patellar ligament attaches to the tibial tubercle but also to the physis of the tibial growth plate and to the periosteum of the metaphysis of the tibia (see figure 1 at top) . Sailley et al propose that this anatomical area is not only prone to traction that we normally associate with OSD, but also compression. Perhaps this explains the sudden onset OSD in the clinic alongside those rumbling insidious case loads.
As I mentioned, we now follow the Strickland protocol at our club in terms of treatment, but I still believe the key is in prevention rather cure. We regularly discuss loading with our coaches at every age group. If you consider that most of our players at school boy level will also play and train for their school, probably be selected for other sports such as cricket and rugby and will generally tear around everywhere at 100mph. Basically their day consists of sprinting, jumping, bounding and kicking. Consider the load on those immature structures (both compressive and tensile). As part of a warm up, does that player then need to do a series of hurdle drills or jumps? Could they not spend their conditioning sessions doing low impact movement patterns, balance & proprioception, or co-ordination drills for their newly elongated and uncontrollable limbs? Perhaps every now and then having a training session where the lads don’t have to strike a ball? Like basketball maybe, where you teach spacial awareness and evading the opponent? Or placing a technical bias on the session and reducing the pace?
If we can help coaches, players and parents understand that modifying activities and occasionally, resting, is the best thing in the long run for all parties, I think we will continue to see a drop in training / matches missed due to OSD.
Yours in sport