The hip joint is made up of the femur (thigh bone) and pelvis (hip bone). It is a ball and socket joint that connects the legs and the torso. The round part of the femoral head acts as a ball and fits into the acetabulum, a cup-like socket of the pelvis. In hemiarthroplasty, only a part of the hip joint, the femoral head is removed, excluding the acetabulum. An arthroplasty, or total hip replacement, will be required if the acetabulum also needs to be replaced.
Hemiarthroplasty is typically performed when there is a break or fracture of the femoral head. The fracture may happen due to a fall, an injury, or an accident. Over half of hip fractures in the elderly are caused by femoral neck fractures, which are exceedingly common. Significant morbidity, mortality, loss of function, and independence in the survivors are possible outcomes. Hemiarthroplasty is usually considered the primary treatment for treating femur fractures. Only the head of the femur is replaced with a prosthesis, not the hip joint as a whole.
All of the hip joint’s components, including the femoral head and socket, are replaced with artificial implants during an arthroplasty. It is typically used for arthritic conditions of the bones. Hemiarthroplasty has a number of benefits over total hip replacement, including reduced blood loss, a shorter recovery period, and a lower risk of hip dislocation following surgery. However, arthroplasty is better than hemiarthroplasty in younger patients due to its lower pain, increased likelihood of walking ability, and improved long-term function.
Types of Hemiarthroplasty
There are different types of hemiarthroplasty which are classified based on certain factors such as:
Based on the Component of the Prosthesis Head
The femoral head is attached to the femoral stem in a fixed, one-piece design. The femoral head always moves with the stem in the same direction as it is not free to move independently on its own. The design and technique are simple and it is often less expensive.
- Austin Moore prosthesis – It has fenestrations in the stem through which bone ingrowth can occur, helping the anchorage of hip prosthesis into the native bone.
- Thompson prosthesis – It does not have fenestrations and it relies on bone cement for the fixation to the native bone.
There is an additional joint between the stem and the head of the prosthesis. The inner femoral head is free to move within the outer acetabular component. The outer acetabular component can rotate independently, providing more freedom of movement. Compared to unipolar prostheses, this dual articulation increases the range of motion, lessens wear and friction on the joint components, provides stability, and may prevent long-term complications like dislocation.
Based on the Assembly of the Prosthesis
The stem and femoral head are one single, solid implant. They have a limited capacity for intraoperative modification and might not accurately restore the patient’s original hip geometry.
All the components of the implant, the head, neck, and stem, are made independently. They can have their size changed during the procedure to precisely restore the patient’s natural hip.
Based on the Femoral Stem Insertion Technique
The use of bone cement is necessary to secure the implants to the bone interface. It has been reported that using cemented implants as opposed to uncemented implants increases mortality.
The hip replacements depend on the implants’ covering growing new bone. Studies reported that there is a decrease in mobility while it increases the pain. There might also be an issue with fixation.
The choice between different hemiarthroplasty types depends on various factors, including the patient’s age, overall health, and the surgeon’s preference. Bipolar prostheses are often considered in cases where there is concern about instability or dislocation. However, each type of prosthesis has its advantages and limitations, and the decision should be made based on the specific needs and conditions of the patient.
Procedure For Performing Hemiarthroplasty
Hemiarthroplasty is typically performed right away following a hip fracture due to a fall or injury. To ensure minimal pain, the procedure is carried out under regional or general anesthesia. The surgeon made an incision around the thigh, near the hip to access the joint. Only the damaged femoral head is removed from the hip joint and the other part is left as such. A metal stem is inserted snugly into the hollowed-out interior of the femur. Some stems will be secured with bone cement to lessen the possibility of a femur fracture. On the stem, which may be connected to an extra headlined with polyethylene, an artificial femoral head is firmly positioned. This is referred to as bipolar prosthesis or a head inside a head. After that, the incision is sewn up and bandaged.
Medications are prescribed to suppress the pain after the surgery. Physical therapy and follow-up appointments are necessary to improve the recovery. Physical therapy is started while the patient is still in hospital and should be continued after being discharged. The duration of therapy depends on many factors including age and patient overall health. It might be required to permanently avoid harsh activities such as heavy lifting and climbing. The ability to run and play sports might also be reduced.
Hemiarthroplasty and Its Associated Complications
Several complications can arise following hemiarthroplasty. Some of the most common complications are:
- Infection- It can happen a few days later or even years after the surgery. It does not occur usually but might be serious if it does as the infection can spread to the other parts of the hip leading to the need for other surgery
- Blood Clots- The risk of the formation of blood clots in the leg vein (deep vein thrombosis) is associated with any surgeries performed in the hip or legs. It can be serious if the clot is big enough to block blood circulation in the leg or if it further travels into the other organs and causes further complications.
- Dislocation of the Implant- It is quite common to happen before the connective tissue in the joint is completely healed.
- Loosening of the Implant- The prosthetic hip is assumed to last around 20 years. If it gets loose before that, it might result in painful complications and other surgery might be needed to fix it.
Additionally, like any medical procedure, the cost of a partial hip replacement surgery can vary depending on several factors. These variables may have an impact on the price of surgical procedures as well as other healthcare services. Hip replacement surgery cost in India is comparatively lower than the other countries such as the US, Russia, Thailand, and other European nations. India offers great treatment quality in addition to being reasonably priced because it has highly skilled surgeons and hospitals with the newest equipment.
Compared to some other surgical interventions, hemiarthroplasty often has a faster recovery time and it is associated with fewer complications. The technique involves replacing only the damaged portion of the hip joint. This can result in a shorter surgery time and less trauma to surrounding tissues. Individuals who are thinking about having a partial hip replacement should talk to their healthcare providers about the specifics of the cost breakdown, ascertain what is included in the quoted amount, and investigate options that suit their needs and preferences.