Spacer mould and method for producing hip spacers

A method for producing a hip spacer, the method comprising:

• filling a femoral head mould of a semi-spherical insert and a hollow body, open on two sides, of an adapter insert with PMMA bone cement and assembling the semi-spherical insert and the adapter insert;
• inserting the assembled and PMMA bone cement-filled semi-spherical insert and adapter insert into a recess of a base element, wherein an excess of PMMA bone cement is severed by cutting edges at a connection between the femoral head mould and the hollow body, wherein the base element comprises a hollow mould as negative image of a part of the femoral stem of the hip spacer to be generated, wherein the hollow mould, after being plugged in, is situated adjacent to the remaining free opening of the hollow body of the adapter insert;
• plugging a head of a core for mechanical stabilisation of the hip spacer into the PMMA bone cement present in the hollow body of the adapter insert connected to the semi-spherical insert, such that a fin of the core is arranged in the hollow mould of the base element;
• filling the femoral head mould of the base element with an excess of PMMA bone cement;
• pushing a punch with a punch hollow mould as negative image of the remaining part of the femoral stem of the hip spacer to be generated onto the PMMA bone cement in the hollow mould, such that the femoral head mould, the hollow body of the adapter insert, the hollow mould of the base element, and the punch hollow mould of the punch define the shape of the hip spacer to be generated, whereby an excess of PMMA bone cement is severed by cutting edges at the connection between the hollow mould of the base element and the punch hollow mould while the punch is being applied;
• and
• taking the finished hip spacer out of the spacer mould after the PMMA bone cement has cured in the spacer mould formed by the base element, the semi-spherical insert, the adapter insert, and the punch.

A hip spacer produced with a spacer mould comprising:

• a base element, in which a hollow mould is provided as negative image of one side of a femoral stem of the hip spacer to be generated, wherein a recess is arranged on the proximal end of the hollow mould in the base element and is connected to the hollow mould;
• a semi-spherical insert comprising a femoral head mould as negative image of one side of a femoral head of the hip spacer to be generated, wherein the semi-spherical insert is or can be arranged in the recess of the base element at a side of the recess that is opposite to the connection to the hollow mould, such that the femoral head mould is aligned in the direction towards the hollow mould;
• an adapter insert designed as a hollow body that is open on two sides and that is or can be arranged in the recess of the base element between the semi-spherical insert and the hollow mould such that the recess exerts a pressure onto the adapter insert and the semi-spherical insert when the adapter insert and the semi-spherical insert are inserted into the recess, wherein the hollow body of the adapter insert connects the femoral head mould of the semi-spherical insert to the hollow mould in the base element;
• and
• a punch that comprises a punch hollow mould in the form of the negative image of the remaining femoral stem and that is arranged on or can be pressed onto the top side of the base element,
• wherein
• a first cutting edge bounding a connection of the hollow mould of the base element to the punch hollow mould of the punch is arranged on the edge of the hollow mould of the base element and/or on the edge of the punch hollow mould of the punch, and
• a second cutting edge bounding a connection of the femoral head mould to the opening of the hollow body of the adapter insert is arranged on the edge of the femoral head mould and/or on the edge of said opening of the hollow body of the adapter insert to the femoral head mould.