An ergonomic knee brace comprising: an upper strut for extending along the upper leg; a lower strut for extending along the lower leg; pivoting arrangements for intercoupling said upper strut and said lower strut; said pivoting arrangements having a center; and said pivoting arrangements including stop assemblies (42, 44) both for flexion and extension, including two substantially aligned catch plates (68, 70) each formed of a flat arcuate disc having an arcuate opening and having stop recesses facing or opening toward the center of said pivoting arrangements, and further comprising inner and outer cover plates (72, 74); at least one of said struts (16, 18) having a flexion stop surface (32, 34) for engaging the flexion stop assembly; and at least one of said struts having an extension stop surface (32, 34) for engaging the extension stop assembly; wherein the stop assemblies further include a movable stop (92, 94) pivoted about the center of the assembly and having an outwardly spring biased pin which serves as a locking member (82, 86) for engaging said stop recesses in each of the two catch plates, coupled to a release button (52, 54) which extends radially outward to the periphery of said pivoting arrangements, and said release button (52, 54) being movable inward to shift said locking member (82, 86) out of said stop recesses to permit angular adjustment of said stop (92, 94). characterized in that the stop assemblies each further comprise a pair of coil springs (96, 98) extending between the movable stop (92, 94) and the release button (52, 54) for biasing the locking pin outwards; and in that a part (42, 44) of said movable stop (92, 94) extends over said outer cover plate, said outer cover plate having angular indicia thereon. an upper strut for extending along the upper leg; a lower strut for extending along the lower leg; pivoting arrangements for intercoupling said upper strut and said lower strut; said pivoting arrangements having a center; and said pivoting arrangements including stop assemblies (42, 44) both for flexion and extension, including two substantially aligned catch plates (68, 70) each formed of a flat arcuate disc having an arcuate opening and having stop recesses facing or opening toward the center of said pivoting arrangements, and further comprising inner and outer cover plates (72, 74); at least one of said struts (16, 18) having a flexion stop surface (32, 34) for engaging the flexion stop assembly; and at least one of said struts having an extension stop surface (32, 34) for engaging the extension stop assembly; wherein the stop assemblies further include a movable stop (92, 94) pivoted about the center of the assembly and having an outwardly spring biased pin which serves as a locking member (82, 86) for engaging said stop recesses in each of the two catch plates, coupled to a release button (52, 54) which extends radially outward to the periphery of said pivoting arrangements, and said release button (52, 54) being movable inward to shift said locking member (82, 86) out of said stop recesses to permit angular adjustment of said stop (92, 94). characterized in that the stop assemblies each further comprise a pair of coil springs (96, 98) extending between the movable stop (92, 94) and the release button (52, 54) for biasing the locking pin outwards; and in that a part (42, 44) of said movable stop (92, 94) extends over said outer cover plate, said outer cover plate having angular indicia thereon.