Abstract: A knee pad assembly for relieving the symptoms of patellar tendinitis, including a pad adapted for being positioned against and molded onto a lower leg in the region of the knee for lying in closely-conforming relation against and applying radially-directed pressure to the attachment site of the patellar tendon to the patella, to the knee joint, and to at least one epicondyle of the tibia. The pad is hardened into a rigid structure for therapeutic use and includes an initially flexible inner substrate impregnated or coated with a reactive system. The system remains stable when maintained in substantially moisture-free conditions and hardens upon exposure to moisture to form a rigid, self-supporting structure having a shape conforming to the lower leg to which the pad is molded during curing. A flexible cover encloses the substrate, and cooperates with the pad for maintaining the pad in its closely-conforming position against the lower leg.