[Medical assessment in the field of Social Act VII: pre-existing damage and causality of apophyseal injuries and detachments].

The medical assessment of affections of the apophyses frequently presents the assessor with problems in causality testing and estimation of functional impairment. Apophyses are the insertion of tendons and are therefore at the center of an acting parallelogram of forces. They fuse via an apophyseal plate in the second decade of life. Depending on the age there is a reduced mechanical load-bearing capacity of the apophyseal plates in the last 1-2 years before complete mineralization of the joint. Two types of injury must be distinguished in an expert opinion: apophyseal detachment as a result of repetitive microtrauma in the event of chronic overload and apophyseal avulsion fracture as an acute injury due to sudden maximum muscle tension. While chronic overload leads to exclusion from insurance cover by the statutory accident insurance, apophyseal avulsion fractures fulfil the necessary requirements for acceptance as an insurance case. The apophyseal avulsion fracture is subject to a time-limited force, which directly leads to damage to health and avulsion of the tibial tuberosity including its tension system. The sudden jerky maximum muscle pull leads to an overload of the tension system and avulsion of the apophysis in cases of an age-related vulnerable apophyseal plate. Once the mineralization is complete, this type of fracture no longer occurs. Osgood-Schlatter disease, an insertion tendinosis of the patellar tendon, occurs in around 20% of all sport-active adolescents but it is questionable whether it can be associated with the acute avulsion fracture. Knowledge of the pathogenesis of affections and injuries of the apophysis can provide the assessor with good foundations for the estimation of a causal association.