A joint protector of a sheet-shaped flexible material, including an essentially tubular body, which is provided with a curved configuration for adaptation to a joint, and which is sewn together with at least one seam, between a first edge of a first material portion and a second edge of a second material portion, is distinguished in that the seam between said edges extends along a curve, which defines a recessed area of material of the first material portion at an essentially central portion of the first edge, and which defines an enlarged area of material of the second material portion at an essentially central portion of the second edge, that the first material portion is provided with a contracting action to the recessed area of material through the seam for achieving a curved configuration of the tubular body. The invention also concerns a blank and a method.