[Why does the patellofemoral cartilage collapse? : A critical analysis of epidemiology, etiology and prevention].

Background: Cartilage damage in the patellofemoral joint is common and often leads to pain-related restrictions in the patients' subjective activity level. The cause is often multifactorial.

Etiology: The most common causes comprise chronic overuse, acute impact trauma, post-traumatic conditions or patellar fractures, while patellar instability with its anatomical risk factors (trochlear dysplasia, patella alta, lateralized tuberosity, genu valgum or torsional deformities) plays a key role. Acute cartilage damage or (osteo-)chondral fractures usually occur in the context of acute patellar dislocation or direct impact trauma. In this regard, early surgical refixation or resection of the (osteo-)chondral fragments is important and can contribute to a delay of further cartilage deterioration. Chronic cartilage damage usually results from a disorder of the patellofemoral kinematics, such as patellar maltracking. (Post-)traumatic conditions such as patellar fractures represent a special entity. Long-term cartilage deterioration and osteoarthritis can also emerge or progress by inadequate surgical procedures.

Therapy: Therapeutically, the main focus should always be on correcting biomechanical imbalances, in order to allow for effective cartilage regeneration. The latter can be achieved by several techniques for cartilage regeneration.