Search

JP-2026076129-A - Devices, methods, and uses for determining distance

JP2026076129AJP 2026076129 AJP2026076129 AJP 2026076129AJP-2026076129-A

Abstract

[Problem] To provide a device, system, and method for manufacturing a joint spacer for determining the required distance between the head region and the shaft region of a joint spacer. [Solution] A device for determining the required distance between the shaft region 3 and the head region 2 of a joint spacer 1 comprises a head and a shaft that can be positioned at different distances from each other, and the device further comprises a fixing device for fixing the distance between the head and the shaft. The device makes it possible to determine the required shape of the hip joint spacer intraoperatively by adjusting the distance from the shaft to the head relative to the patient's specific anatomical structure. [Selection Diagram] Figure 9

Inventors

  • ミヒャエル シュミッツ
  • ハラルト グリュン
  • クリスティアン クンケル
  • ヨッヒェン ポールマン
  • セバスティアン フォークト

Assignees

  • ヘレウス メディカル ゲーエムベーハー

Dates

Publication Date
20260511
Application Date
20251020
Priority Date
20241023

Claims (15)

  1. A device (10) for determining the required distance from the shaft region (3) to the head region (2) of a joint spacer (1), comprising a head (11) and a shaft (13) that can be positioned at different distances from each other, wherein the device (10) further comprises a fixing device (15) for fixing the distance between the head (11) and the shaft (13).
  2. The device (10) according to claim 1, further comprising a neck (12) connecting the head (11) to the shaft (13).
  3. The device (10) according to claim 1, characterized in that the head (11) on one side and the shaft (13) and/or the neck (12) on the other side are separated from each other, or can be separated from each other.
  4. The device (10) according to claim 2, characterized in that the head (11) is displaceable on the neck (12), and the fixing device (15) comprises at least one pin (17) and a plurality of shape locking elements (18), wherein the pin (17) can be made to contact one or two shape locking elements (18) so as to prevent the displacement of the head (11) on the neck (12).
  5. The device (10) according to claim 4, characterized in that axially aligned grooves (19) are arranged adjacent to the plurality of shape locking elements (18), and the pins (17) can be displaced axially within the grooves (19) to adjust the distance.
  6. The device (10) according to claim 1, characterized in that the fixing device (15) includes a switching device (20) for switching from an open position (21) to a closed position (22), the distance between the head (11) and the shaft (13) can be changed in the open position (21), and the distance between the head (11) and the shaft (13) is fixed in the closed position (22).
  7. The device (10) according to claims 2 and 6, characterized in that the switching is performed by the rotation of the rotating unit (26) relative to the housing portion (23) around the longitudinal axis (25) of the neck (12).
  8. The device (10) according to claim 6, characterized in that it is provided with a locking element (27) that is activated when switching to the closed position (22) and prevents any movement between the head (11) and the shaft (13).
  9. The device (10) according to claim 8, characterized in that the locking element (27) is connected to a spring-loaded button (30) that cooperates with two recesses (31, 32), the button (30) being positioned in the first recess (31) when the fixing device (15) is in the closed position (22), and the button (30) being positioned in the second recess (32) when the fixing device (15) is in the open position (21).
  10. The device (10) according to claim 4, wherein the fixing device (15) further comprises at least one further pin (17') located at a position rotated 180° around the longitudinal axis (25) starting from the pin (17), and the fixing device (15) further comprises a further plurality of shape-locking elements (18') located at a position rotated 180° around the longitudinal axis (25) starting from the plurality of shape-locking elements (18).
  11. The device (10) according to claim 1, wherein the device (10) comprises an outer shell (35) in the region of the head (11) and/or the shaft (13), the outer shell defining a cavity (34) outward, and a filling opening (36) for filling the cavity (34) with bone cement is provided in the outer shell (35).
  12. The device (10) described in claim 1, - At least one additional head (11) that can be positioned on the shaft (13) of the device (10), and/or - At least one additional shaft (13) that can position the head (11) of the device (10), and/or - At least one additional shaft (13) that can position the head (11) of the device (10), and is of a different size from the shaft (13) of the device (10), A system equipped with these features.
  13. A method for manufacturing a joint spacer (1), wherein the head (11) and shaft (13) of a device (10) are positioned at a desired distance from each other, the distance is fixed, and bone cement (40) is filled into the head (11) and/or the shaft (13).
  14. The method according to claim 13, wherein the outer shell (35) of the device (10) forms the outer shell (5) of the joint spacer (1).
  15. Use of a disappearing mold for manufacturing the aforementioned joint spacer (1).

Description

This invention relates to a device, system, method for manufacturing a joint spacer, and use for determining the required distance between the head region and the shaft region of a joint spacer. Preferably, the device is also designed to combine any head with any shaft in order to obtain a joint spacer that is optimally fitted to the patient's anatomical structure. In the context of two-stage total joint replacement surgery, such as for the hip or shoulder, spacers are used as temporary placeholders during the intermediate period. These spacers are particularly used in septic replacement operations. Such spacers are often fabricated intraoperatively by medical personnel from bone cement, such as polymethyl methacrylate bone cement. During the fabrication of these spacers, one or more antibiotics specifically formulated for the present bacteria may be added to the bone cement, depending on available antibiotic susceptibility testing for the infection-causing microorganisms. While readily available, prefabricated spacers already exist that offer excellent stability but do not conform to the individual anatomical structure of each patient. Therefore, it is preferable that individual spacers be fabricated during surgery. In the intraoperative fabrication of spacers using conventional bone cement, plastic molds are commonly used, as described, for example, in U.S. Patent No. 6,361,731 (B1). These molds can be manufactured using spacer heads of different diameters. In this case, the medical user can select from a predetermined range of spacer head sizes. Thus, customized spacers can be provided to patients according to specific anatomical conditions. Spacers for joints or joint sites are called joint spacers. In more advanced forms, U.S. Patents 7,637,729 (B2), 7,789,646 (B2), 8,480,389 (B2), and 8,801,983 (B2) propose multi-part molds for the manufacture of modular hip spacers. The molds in U.S. Patents 7,789,646 (B2), 8,480,389 (B2), and 8,801,983 (B2) consist of a mold for a shaft that can be connected to a mold for a spacer head. Molds for spacer heads with different diameters are available. The shaft mold is connected to a spacer head mold of the selected diameter. The mold thus assembled can then be filled with bone cement. After hardening, the formed hip spacer is removed. European Patent No. 3957280 (B1) describes a device for manufacturing hip joint spacers that enables the production of patient-specific hip joint spacers with respect to the size of the spacer head and the distance of the head from the femoral shaft (femoral offset). This allows for further adjustment of the spacer. The objective of this invention is to easily and reproducibly determine the required shape of a joint spacer in order to improve the manufacturing of individually tailored joint spacers. This objective is achieved by the device described in claim 1, and by the systems, methods, and uses described in the related claims. Advantageous embodiments can be found in the dependent claims. To achieve this objective, a device is used to determine the required distance between the head region and the shaft region of the joint spacer. This device comprises a head and a shaft that can be positioned at different distances from each other. The device further includes a fixing device for fixing the distance between the head and the shaft. This device is designed to be temporarily inserted into a patient's body at the location where a spacer will be inserted, in order to determine the required distance between the head and shaft regions of the spacer, or to determine whether the selected distance is suitable for specific anatomical conditions. The device is designed to fix the selected distance between the head and shaft, thereby preventing the possibility of unexpected separation of the shaft and head, which could lead to unexpected changes in the distance or loss of the head. In particular, this distance is fixed during use in the patient's body. This device may also be called a test gauge. The device allows for the determination of the required shape of the hip spacer during surgery by adjusting the distance from the shaft to the head (also known as the "femoral offset") relative to the patient's specific anatomical structure. This means that the correct spacer can be individually selected for each patient. For example, the spacer can be manufactured during surgery using a hip spacer mold and/or according to European Patent No. 3957280 (B1). The manufactured and inserted spacer includes a head region (head), a shaft region (shaft), and, optionally, an intermediate neck region (neck) connecting the head region and the shaft region. The spacer is modeled, particularly in its head region, based on the shape and size of the corresponding bone, such as the femur (thigh bone). The shaft region of the spacer is inserted into an opening in the bone and typically fixed therein. The head region of the spacer is substantially spherical in at least so