Total hip replacement

Total hip arthroplasty is a replacing of the hip joint with an artificial joint, comprising the femoral head and the acetabulum.

Reasons for replacement
Total hip replacement is indicated if conservative treatment fails. The most common reason for undergoing this surgery is advanced arthrosis causing pain and limitation of mobility. Another common reason is a fracture of the femoral neck in the elderly population and/or in an inappropriate (adduction) position. Further indications can be, for example, a congenital deformity, tumor involvement of the area, Perthes disease or reimplantation of a previous replacement.

Types of implants
The basic types of implants are the cemented prosthesis and uncemented prosthesis, depending on whether bone cement (polymethyl methacrylate) is used to fixate them. The so-called hybrid replacement combines the previous two types, whereby only the femoral head is fixated using bone cement.

The cemented prosthesis has a smooth surface and its main advantage is a possibility of full loading after surgery. However, a possible replacement after wearing down may be technically demanding and challenging for the surgeon. At the same time, a significant disadvantage is the possibility of wearing down at the connection between the cement and the prosthesis due to physical exertion. It implies that cemented prosthesis is more suitable for elderly patients who benefit from earlier rehabilitation and for whom endoprosthesis replacement isn't expected, as well as its excessive overloading.

The uncemented prosthesis has a rough surface, which stimulates ossification around the implant and gradually leads to its stable anchoring. It is not possible to fully load it after the surgery, but with good bone quality it can bear a higher mechanical load, and at the same time, the absence of cement allows an easier replacement of the prosthesis. Therefore, it is suitable for younger and more active patients (mostly under 75 years) without osteoporosis.

Another alternative for certain patients can be the hip resurfacing method, which design resembles a cap on the femoral head and tries to imitate a healthy joint as accurately as possible. At this point, due to problems with more frequent revisions, it has not found a wide implementation.

Endoprostheses are mostly made of titanium or cobalt/chromium alloys. Between the head and the acetabulum there is a so-called inlay made of polyethylene, which reduces friction during the movement of metal components. Just like any material, the aforementioned implants have a lifespan and need to be replaced after approximately fifteen years.

Indications
The indication for a total hip replacement is a significantly impaired function of the joint, or the joint being a source of very intense pain.

Contraindications
The main contraindications to total replacement are advanced internal diseases and the presence of infection in the organism.

Procedure
If the doctor recommends surgery to the patient, several pre-operative checkups need to take place. If there is, for example, an infection or inflammation in the hip, the surgery must be postponed. The procedure is performed in a perfectly aseptic environment to prevent the occurrence of postoperative infection. The entire surgery takes approximately one to one and a half hour, and the patient is most often put under general anesthesia. If the patient wants to remain conscious, the anesthesia is only done from the waist down. The patient is usually operated on his side. After replacing parts of the bones with prostheses, it is necessary to check their stability before the wound is sutured. After the surgery, the patient is transferred to the intensive care unit, where he remains for three days to be monitored. From approximately the second day after surgery, rehabilitation exercises will begin under the supervision of a physiotherapist.

During the surgery

 * Fracture, for example of the femur - is solved with osteosynthesis
 * Vessel injury - smaller branches are ligated, larger ones require revision and suturing of the femoral artery
 * Nerve injury

Post-operative

 * Bleeding
 *  Endoprosthesis luxation - repositioning is attempted under general anesthesia
 * Thromboembolic disease - prevention is important here, such as rehabilitation and bandages
 * Infection - manifested by redness, swelling, fever, increased sedimentation and CRP

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