Siding- Larsen- Johansson syndrome shows a ismilar pathogenesis to the Osgood- Schlatter syndrome, with the two syndromes sometimes occur simultaneously (Valentino, Quiligotti and Ruggirello, 2012). It refers to an injury to the bone growth plate at the bottom of the knee cap which occurs in younger athletes.
The large muscle on the front of the thigh (quadriceps) attaches to the knee cap which, in turn, is attached to the shin bone (tibia) via the patellar tendon. The function of this tendon is to transmit forces produced by the thigh muscle from the kneecap to the shin to support and move the knee joint.
In children, the portion of the knee cap from which the patellar tendon originates is separated from the bulk of the knee cap by a growth plate. This growth plate enables bone growth to occur. However, it also represents a site of weakness in the bone. Forcible and repeated contraction of the thigh muscle can injure the growth plate. This commonly occurs in sports which involve running and jumping and occurs during a period of rapid growth. During rapid growth, the thigh muscle and patellar tendon become tighter as the bones grow. This leads to increased pulling of the patellar tendon on the knee cap and growth plate.
Completely refrain from sports activity; physiotherapy for acute treatment (soft tissue techniques, hands on treatment) and slowly easing back into activity, depending on the pain level.
Valentino M., Quiligotti C. and Ruggirello M., 2012, Siding- Larsen- Johansson syndrome: A case report, Journal of Ultrasound, 15(2), pp: 127-129