Osgood Schlatter disease

In sporty teenagers, trouble below the kneecap is common. Juan Agustin Soler and Fares Haddad provide an update

Non-traumatic knee pain is a frequent complaint among adolescents. A common cause for the symptoms is Osgood-Schlatter disease. This is perhaps a misnomer, as it is not a disease but an orthopaedic condition, first described separately by Osgood and Schlatter in 1903. It is characterised by pain at the front of the knee, and, more specifically, pain arising from the anterior tibial tuberosity (top protuberance of the main shin bone). It can be defined as an apophysitis, which means an inflammation of an apophysis (bony protuberance). This condition must be differentiated from another common ‘growing pains’ complaint, Sinding-Larsen- Johansson syndrome, in which the pain arises a little further up from the tibial tuberosity, at the junction of the patella and patellar tendon.

Osgood-Schlatter disease is most commonly found in children, and particularly among boys, aged 11 to 15. It is more common among young people who are very active in sports, particularly those that involve jumping. The condition usually resolves by the age of 15 or once the growth plate of the anterior tibial tuberosity fuses.

The exact incidence of this condition is not known as, to date, no reliable epidemiological data has been published. One indication, however, comes from a 1985 retrospective study by Kujala et al(1) on the incidence and duration of Osgood-Schlatter.

[065-IMAGE4]

[065-IMAGE5]

Among 412 adolescents, they reported an incidence of 12.9%.

The accepted theory for the condition (as yet not proven) is that of a repetitive traction injury of the tibial tubercle during the growth spurt. The large quadriceps muscles span from the thigh and come together to form the quadriceps tendon. This tendon continues its course inserting into and running through the patella. It emerges at the inferior pole (bottom end) of the patella as the patellar tendon and continues its downward course to insert finally into the tibial tuberosity (see figures 1 and 2, p7). Extension of the knee, when the quadriceps muscle is contracted, is a result of the pull of the patellar tendon on the tibial tuberosity.

In the immature skeleton, the growth plates (physes) have not yet fused. The intense repetitive traction forces that are generated by the quadriceps muscles on the tibial tuberosity may be the cause of the pain. Some authors have even suggested that the traction forces on the tubercle produce an incomplete avulsion fracture. In either scenario, it is important to understand that the problem arises in the tibial tubercle, not the knee joint, so it is an extra-articular problem.

The pain from Osgood-Schlatter’s disease can be reproduced by squatting on the knee in full flexion, knee extension against resistance, or stressing the quadriceps muscle group. The pain is worse on running, jumping, kneeling, or going up or down stairs. Pain usually settles with rest or decreased activity. In a number of cases, the pain can affect both knees, simultaneously or at separate times.

On physical examination the therapist can see a swelling at the tibial tubercle, which can be red and warm to the touch. The tubercle may be tender when palpated and may have a firm mass. The knee joint will be normal on examination. Some clients may present with a degree of quadriceps atrophy, the result of decreased use because of pain.

The diagnosis is mainly clinical, so x-rays are not generally needed, but they can be helpful to rule out possible malignancies or infections. The condition is benign and selflimiting – and it is essential that the patient and their parents be reassured about this. Even so, symptoms may last from a few weeks to a few months. Rest, ice, and elevation are the best forms of treatment.

In rare circumstances, or in cases where the condition is extremely acute, the knee can be immobilised in a cast or a hinge brace locked in extension until symptoms subside. Analgesics, such as paracetemol, or non-steroidal anti-inflammatories, can be very helpful. Physical activity should be limited until symptoms resolve. It is common for a residual bump to persist for life on the tibial tuberosity.

Once the acute pain has resolved, the young person can return to physical activity. It is at this point that physiotherapy is of most help. Exercise programmes should be tailored to the client’s symptoms: footballers, in particular, must reduce the number of games they play, to keep discomfort under control. Helpful exercise regimes include quadriceps stretching and hip extension to stretch the extensor mechanism fully, plus hamstring stretching in many cases where the hamstrings are tight.

Every effort should be made to encourage the young athlete to maintain their motivation, optimise their biomechanics and to understand that the problem will pass – and that they will be able to return to the same activity level as their peers.

Reference

1. Kujala UM, Kvist M and Heinonen O, ‘Osgood- Schlatter’s Disease in Adolescent Athletes. Retrospective Study of Incidence and Duration’, American Journal of Sports Medicine, Vol 13, Issue 4 236-241