pivot elements on the plate links 42 coacting headed pin fasteners 45 are received within the bores of elements 44 to complete the construction of the articulated brace section which is highly flexible in a direction across the axes of pivot elements 44 and 45 and highly rigid or resistant to bending in a right angular direction the top and bottommost plate links 40 and 42 of each articulated brace section 39 are pivotally joined to downwardly and upwardly extending plate like terminals 46 and 47 of the two bands 35 and 34 which complete the formation of the side articulated brace sections as should now be apparent the brace sections 39 are located on the device to allow free bending of the knee in the normal plane fore and aft while serving as rigid braces to resist bending of the knee joint laterally due to a blow on either side of the knee which the knee cannot withstand readily as is well known the brace 33 thus augments the protective action of the rubber like body portion 20 with its internal shock absorbing fluid filled compartments 27 and 28 having the described ability to reinforce one another by fluid flow following impact to strengthen the protector at the side opposite to the point of impact to further strengthen the protector tough cords 48 of nylon or equivalent material interconnect the ends of brace bands 34 and 35 with plate elements 49 fig8 embedded in the top and bottom rear extensions 50 having.