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Rev . Medicina Desportiva informa , 2018 ; 9 ( 3 ): 10-13
Pathology of the Cartilage in Children and Adolescents in Sports Practice . Treatment and Prevention
Dr . Alexandre Rebelo-Marques 1-3 , Prof . Doctor João Páscoa Pinheiro 1 , 3 , 4
1 . 2
Faculty of Medicine of the University of Coimbra ; 2 Dragon Clinic , Espregueira-Mendes Sports Centre – FIFA Medical Centre of Excellence ; 3 Specialist in physical medicine and rehabilitation and 4 Sports medicine . Service of physical medicine and Rehabilitation , hospital and University Center of Coimbra .
ABSTRACT
The growing demand of sports training in children and adolescents determines a greater frequency of cartilage pathology . Hyaline cartilage is a viscoelastic connective tissue of great structural complexity and remarkable strength , playing an important role in joint protection . When injured , it presents limitations of regeneration and healing , thus conditioning a strong impact on sports activities . Pathogenesis of injuries is distributed between macro ( acute lesion ) and micro-traumatology ( chronic lesion ). Therapeutic recommendations are controversial , both in conservative and surgical therapy . Education of the athlete and the different sports agents is an essential element in the prevention of injury . Clinical research in this pathology and in this population , is limited and usually of low evidence . This article intends to present several clinical elements , in the fields of prevention and therapeutics , supported by the evidence and directed to this specific population .
KEYWORDS
Cartilage , Treatment , Prevention , Child , Adolescents
Introduction
Children and adolescents start early in the sport , which justifies the increasing number of sporting injuries in this Group . This population has morpho-anthropometric characteristics , favoring specific joint pathologies . The quality of the training method and the characteristics of the dominant technical gesture also justify the commitment of the musculoskeletal system , particularly in microtraumatic pathology .
The pathology of cartilage is frequent justifying a great diversity of symptomatic clinic and placing various sporting restrictions and of functional prognosis in adulthood .
The cartilage is a viscoelastic connective tissue formed still in the embryonic stage of human development , before the onset of bone formation . 1 , 2 Its main components are specialized cells , chondrocytes , water and components of the extracellular matrix , mainly collagen ( type II – 90-95 %), which gives it great resilience and elasticity . 1 , 3 The hyaline cartilage , coating the articular surfaces , is present in the synovial joints and has important mechanical actions , such as the load distribution , absorption of the impact and friction reduction during the movement . 3 As an example , the knee can withstand loads up to six times the body weight . 2 , 4 After the formation , the hyaline cartilage suffers remodeling , gaining in the maturity of the skeletal system a heterogenic structure with three differentiated layers , in which cells and components of the matrix have different orientations and concentrations . 3 Due to their low cellular density and low proliferative activity and to their avascular character cartilage is virtually unable to regenerate after injury or degeneration caused by common diseases such as osteoarthritis when traumatized 1 , it rarely recovers structure and function and easily can suffer degeneration with functional deterioration in the movement . 1 , 3
The nutrition of the cartilage is mainly done by synovial fluid . But unlike what happens in the adult , in children the bone / cartilage interface is permeable to water and solutes . 5
The cartilage is subjected to several mechanical loads , both static and dynamic . Its ability to sustain compression , traction and shear forces is related to the composition and integrity of the extracellular matrix . The rigidity and permeability are related to the content of proteoglycans and collagen fibers while the tension and elasticity are related to the three-dimensional configuration of the collagen fibers . 3
When the cartilaginous tissue suffers a compression , the extracellular matrix liquid leaves the retinaculum of the proteoglycans , reducing the hydration of the negative loads of those macromolecules that repel , thus increasing the rigidity of the tissue Cartilaginous and reducing their deformation . The solid phase is elastic and not compressible , absorbing only 5 % of the loads applied to the joint , while the liquid phase is compressible and not viscous , absorbing the remaining 95 %. After an impact , all the cartilage behaves as a solid phase not compressible because the fluid has no time to flow through the solid phase . 6 , 7
The load and consequent deformation of the cartilage cause modifications to the extracellular matrix and cellular metabolism . The compression of 25 – 30 % may be the threshold after which the chondrocytes can be permanently deformed , by the rupture or reorganization of the cytoskeleton . Static compression makes it easy to Down-Regulate , the gene expression and the production of type II collagen ( aggrecans and non-collagenic proteins ). The intense load and the cyclical load increase the protein production and the prolonged immobilization , and the reduced load leads to the decrease in the synthesis of proteoglycans and the softening of the cartilage ( also called of chondromalacia ). 3
Injury , treatment and prevention
The lesion of the articular cartilage , with or without the involvement of the subchondral bone , is a potentially serious clinical condition , considering the reduced healing capacity . The repair process leads to the formation of fibrocartilage , not hyaline , with different biomechanical properties , less resistant and less suitable to the support of the joint load . 8 Only small lesions can regenerate and larger lesions and encompassing greater thickness of cartilage rarely heal spontaneously . 9
10 may 2018 www . revdesportiva . pt