On this page, you will find information on the implantation of artificial hip joints, in particular, information about the models we use, taking into account the individual situation of patients, the preparation for surgery and post-operative treatment.
Principles of treatment and models of endoprostheses
The principle of implantation of the artificial hip joint is to replace the damaged parts of the joint (femoral head or acetabulum). Due to this, the friction between the femoral head and the acetabulum is completely reduced, which allows to remove joint pains, increase the mobility of the joint and restore almost normal gait.
The artificial femoral head consists of metal and ceramics. It is installed in the metal leg of the prosthesis (in the method with uncemented fixation, the leg is made of titanium alloy), which is fixed in the femur. For this, the femur should be hollow. To remove bone substance from the bone cavity, blades of different sizes are used, which in shape correspond to the shape of the implantable leg of the prosthesis. In the implantation method with uncemented fixing, doctors have 13 different sizes of prosthesis, so it is a very good possibility of individual selection of the implant taking into account the individual needs of the patient. When implantation with cement fixation, the leg of the prosthesis is fixed (cemented) with bone cement (polymethylmethacrylate) in the femur. When implantation with uncemented fixation, it is stabilized directly by the bone. Depending on the type of fixation, the legs of the prosthesis have the special design.
The cup of the prosthesis consists of two parts. First, from the sliding surface along which the femoral head slides, and second, from the shell, by means of which the cup is fixed in the hip bone. The sliding surface is made of metal or polyethylene (synthetic material); the shell is made of titanium alloy. Fixation of the cup in the pelvis is carried out by counter milling and cup fitting to the diameter of the existing natural cavity (different cups of 11 sizes are available), as well as using two screws that are on the shell and immersed in the pelvic bone. In addition, 2-3 screws are also installed to achieve maximum stability of the prosthesis cup. Alternatively, it is also possible to cement the cup.
The above-described methods of attachment, especially fixing the leg of the prosthesis, have certain advantages and disadvantages. The main advantage of the cement fixation technique is that the patient, immediately after the operation, can fully load the operated leg, transferring the whole mass of his body to it. In addition, with the technique of uncemented fixation, the load on the leg is limited to the pain threshold, and only after 4 weeks, the full load on the extremity is possible. This time is necessary to ensure that the bone is firmly connected (fused) with the leg of the prosthesis.
Over time, cement can begin to “break down” and the prosthesis will loosen, that is, there will be a need for the operation to replace the prosthesis. Duration of service of 90% of prostheses is 10 years or more, after this time this problem arises more often.
At least, theoretically, the advantage of uncemented fixation is the absence of loosening of the leg of the prosthesis. The prosthetic leg we used with uncemented fixation within the framework of the “Swedish study” (reference) showed an excellent index of strength, so we hope that with the proper fusion of the prosthesis, the patient will wear it throughout his life.
Due to the correct shape, screws and framing nails, the cups we use can withstand the full load.
Based on these advantages and disadvantages, we have made the following recommendations for our patients. Nevertheless, when choosing a method, the individual structure of the patient is taken into account, which can lead to disorders from the following recommendations:
Patients younger than 60 years, as a rule, are implanted a total endoprosthesis with completely uncemented fixation.
Patients older than 75 years are implanted, as a rule, a cup with uncemented fixation and a framing nail with cement fixation (the so-called total hybrid (combined) endoprosthesis)
The prognosis after implantation of an artificial hip joint depends on many factors. The cause of loosening of the prosthesis are permanent processes of degeneration and bone mass buildup. These processes of bone mass degeneration and buildup have great individual differences and depend on many factors, which makes it impossible to predict the development of the situation after the operation. When the prosthesis is loosened, complaints often appear, similar to complaints before the implantation of the prosthesis.
Planning and preparation for the operation
Planning the operation and preparing for its performing, we begin with the thorough examination and detailed interview with the chief doctor.
Within the framework of the examination and during a conversation with a specialist, various options for performing the operation and options for replacing the joint are considered taking into account the individual situation of the patient. Therefore, the patient must necessarily bring with him the available X-ray images.
In addition, it makes sense already on the advice to have a list of currently prescribed medications, since the intake of certain medications should be stopped already a few days before the operation.
To achieve the optimal result of treatment, post-operative treatment is crucial. Even before the operation, each patient receives a brochure, which contains important tips for the postoperative period.
The course of postoperative treatment depends, of course, on the type of implant prosthesis; however, all patients on the first day after the operation are engaged in exercise therapy under the supervision of specialists.
On the first day, patients should get out of bed and try to walk – naturally, with the support of our nurses and sanitary assistants or specialists in exercise therapy. Thanks to the appropriate analgesic therapy (a constant scheme of taking medications with a daily repeated questioning of patients regarding their condition/presence of pains), it proceeds as painlessly as possible.
Patients with an endoprosthesis with uncemented fixation can load the operated leg to the painful limit, even if this implies a full load. In any case, the full load is allowed after 4 weeks.
After the removal of the drainage tubes (2-3 days after the operation), all patients can perform daily exercises in the medical pool of our Department of Physiotherapy and Physical Therapy. Therefore, please bring a swimsuit or swimming trunks to the Clinic.
By the time of discharge, patients can independently move around the Department, as well as scale the steps.