A device for producing a knee spacer component (110, 210, 410) by curing bone cement paste (50, 51), wherein the knee spacer component (110, 210, 410) is provided in the medical field for temporarily replacing part of a knee joint comprising an articulating surface of the knee joint, the device having a casting mold for molding the knee spacer component (110, 210, 410) from bone cement paste (50, 51); a valve seat (3, 63, 163, 263, 363) which is connected to the casting mold, wherein the valve seat (3, 63, 163, 263, 363) has a regionally closed head side (4, 64, 164, 264, 364) with at least one first feed-through (5, 65, 165, 265, 365), wherein the at least one first feed-through (5, 65, 165, 265, 365) opens into the casting mold; a valve body (6, 18, 78, 178, 266, 366) which is mounted so as to be rotatable relative to the valve seat (3, 63, 163, 263, 363) and which has a sealing face (7, 67, 167, 267), wherein the sealing face (7, 67, 167, 267) is oriented in the direction of the regionally closed head side (4, 64, 164, 264, 364) of the valve seat (3, 63, 163, 263, 363), wherein at least one second feed-through (8, 21, 68, 168, 268) is arranged in the sealing face (7, 67, 167, 267); wherein the valve seat (3, 63, 163, 263, 363) and the valve body (6, 18, 78, 178, 266, 366) together form a valve, wherein the valve is reversibly transferable into an open position and a closed position by rotation of the valve body (6, 18, 78, 178, 266, 366) relative to the valve seat (3, 63, 163, 263, 363), wherein, in the open position of the valve, the at least one first feed-through (5, 65, 165, 265, 365) of the valve seat (3, 63, 163, 263, 363) and the at least one second feed-through (8, 21, 68, 168, 268) of the valve body (6, 18, 78, 178, 266, 366) are located above one another at least in places and provide a connection through the valve which is permeable to bone cement paste (50, 51), wherein, in the closed position of the valve, the at least one first feed-through (5, 65, 165, 265, 365) of the valve seat (3, 63, 163, 263, 363) is covered by the sealing face (7, 67, 167, 267) of the valve body (6, 18, 78, 178, 266, 366), wherein, in the closed position of the valve, the casting mold is closed in liquid-tight manner for bone cement paste (50, 51). a casting mold for molding the knee spacer component (110, 210, 410) from bone cement paste (50, 51); a valve seat (3, 63, 163, 263, 363) which is connected to the casting mold, wherein the valve seat (3, 63, 163, 263, 363) has a regionally closed head side (4, 64, 164, 264, 364) with at least one first feed-through (5, 65, 165, 265, 365), wherein the at least one first feed-through (5, 65, 165, 265, 365) opens into the casting mold; a valve body (6, 18, 78, 178, 266, 366) which is mounted so as to be rotatable relative to the valve seat (3, 63, 163, 263, 363) and which has a sealing face (7, 67, 167, 267), wherein the sealing face (7, 67, 167, 267) is oriented in the direction of the regionally closed head side (4, 64, 164, 264, 364) of the valve seat (3, 63, 163, 263, 363), wherein at least one second feed-through (8, 21, 68, 168, 268) is arranged in the sealing face (7, 67, 167, 267); wherein the valve seat (3, 63, 163, 263, 363) and the valve body (6, 18, 78, 178, 266, 366) together form a valve, wherein the valve is reversibly transferable into an open position and a closed position by rotation of the valve body (6, 18, 78, 178, 266, 366) relative to the valve seat (3, 63, 163, 263, 363), wherein, in the open position of the valve, the at least one first feed-through (5, 65, 165, 265, 365) of the valve seat (3, 63, 163, 263, 363) and the at least one second feed-through (8, 21, 68, 168, 268) of the valve body (6, 18, 78, 178, 266, 366) are located above one another at least in places and provide a connection through the valve which is permeable to bone cement paste (50, 51), wherein, in the closed position of the valve, the at least one first feed-through (5, 65, 165, 265, 365) of the valve seat (3, 63, 163, 263, 363) is covered by the sealing face (7, 67, 167, 267) of the valve body (6, 18, 78, 178, 266, 366), wherein, in the closed position of the valve, the casting mold is closed in liquid-tight manner for bone cement paste (50, 51).