Hip joint endoprosthesis are artificial hip joints that are intended to replace a missing or damaged hip joint. The endoprosthesis helps to recreate the anatomy of a hip joint and to restore its functions.
Hip joint endoprosthesis consists of the following main components: a femoral stem, a liner and an acetabular component. These components may be standard or patient-specific. In cases of severe conditions (for instance, large bone defects, severe deformation, pelvic discontinuity or complications related to the existing implants), a patient-specific implant is recommended to be used.
Patient-specific hip joint implants and patient-specific surgical guides are designed on a patient’s pelvic-femoral anatomical model recreated from computed tomography (CT) images. Unlike standard modular implants used to treat severe clinical conditions, patient-specific hip implants are designed as a single device with anatomically adapted surfaces, which not only eliminates the risk of instability, adapts the implant to the bone rather than the bone to the implant (during surgery, there is no need to shape the bone in order to adapt it to the implant or use bone cement together with metal acetabular meshes and augments to fill the bone defect), but also restores the biomechanics of the joint with regard to altered axes of knee and ankle joints. The unique patient-specific design solutions allow optimal positioning of primary fixation screws. Secondary fixation to the bone is ensured by the bone osteointegration into surfaces formed from trabecular metal, whose depth is technologically unlimited. All other advantages of patient-specific implants compared to standard implants arise from the design and the construction of an individual implant and the level of product personalisation.
Adjustment of patient-specific hip joint endoprosthesis components with standard implant components
The components of the hip joint endoprosthesis – the stem, the cup and the liner – can all be manufactured patient-specific; in the case of one or two of the components are manufactured patient-specific, they come adjusted to the standard components and fixation screws to complete the endoprosthetic system. For example, a patient-specific acetabular component is used together with a standard liner and standard femoral stem; or a patient-specific femoral stem comes with a standard liner and patient-specific acetabular component.
In clinical practice, a patient-specific femoral stem is used quite seldom (for instance, for patients with a severe hip joint deformation or significant proximal femoral defect). The patient-specific component is more frequently used for the acetabulum revision surgeries. In this case, a patient-specific acetabular implant comes with a standard liner, and the femoral stem, if there are no specific indications, is left the same.
Patient-specific acetabular implants manufactured by Ortho Baltic, in most cases, come with standard certified (with CE marking) liners made from biocompatible UHMWPE or MP-1™ material. However, in atypical cases, we manufacture liners from the same materials using 5+1 axis milling technology. MP-1™ is a new material produced in Israel, clinically tested in New Zealand and Israel, and registered in the U.S. and EU, that shows better biocompatibility and technical characteristics than UHMWPE. Its technical specifications and clinical research data are provided here. Cement or mechanical fixation is used to fixate the liner into the cup component.
Manufacturing and materials used by Ortho Baltic for patient-specific hip joint endoprosthesis
Ortho Baltic patient-specific hip joint endoprosthesis are registered in the State Health Care Accreditation Agency under the Ministry of Health of the Republic of Lithuania. All the materials, software and hardware used in the manufacture of patient-specific implants and surgical guides are certified.
To manufacture patient-specific hip joint implants, Ortho Baltic uses the following materials and manufacturing technologies:
- metal components are manufactured from medical Grade 5 titanium alloy Ti6Al4V using additive manufacturing technology DMLS;
- single-use patient-specific surgical guides, patient-specific anatomical and implant models used in presurgical planning as well as for planning and training purposes during surgeries are printed from biocompatible polymer (PA 2200, also known as Nylon-12), using additive manufacturing technology SLS;
- to manufacture acetabular liners (if patient-specific liners are requested), we use UHMWPE or MP-1™ polymers and a 5+1 axis milling technology.
After 3D printing and / or milling, implant (and surgical guides) are processed using various surface finishing technologies in order to ensure their compliance with the requirements defined by the harmonised product standards. Detailed information about patient-specific implant design, manufacture and validation process are available here.
Composition of Ortho Baltic patient-specific hip joint endoprosthesis package
The package of Ortho Baltic patient-specific hip endoprosthesis includes the following items:
- Patient-specific implant;
- Patient-specific implant trial (optional);
- Patient-specific surgical guides (optional);
- Patient-specific anatomical and implant models (virtual or materialized) intended to be used for presurgical planning;
- Standard implant fixation screws (if a patient-specific cup component is ordered);
- Polyethylene (UHMWPE or MP-1™) cup liner (optional);
- Documentation (implant passport, instructions for use, etc.)
To fixate implants to the bone, standard surgical instruments intended for primary / revision endoprosthesis surgeries are used. Ortho Baltic ensures the compatibility of the implant fixation solution with the instruments of the surgeon / healthcare institution.
If you would like to order a patient-specific hip implant, have any questions or any specific requirements concerning the patient-specific implant package, please fill out the form below: