A total hip joint replacement is an operation to remove a severely impaired hip joint and replace it with an artificial joint (prosthesis). The aim of the surgery is to relieve pain and restore function to the joint.
Total hip joint replacement (total hip arthroplasty) is a common operation undertaken in New Zealand as elective (non-urgent) surgery in both public and private hospitals, typically involving a 4 to 7 day hospital stay. If the operation is undertaken privately (i.e in a private hospital and paid for by the patient or through health insurance), the cost is likely to be between $20,600 and $29,300 (Health Funds Association 2017).
There have been concerns about some metal-on-metal hip prostheses wearing out sooner than anticipated. People who have had a hip replacement and have concerns, or are experiencing pain or discomfort, should see their doctor. Despite these concerns, hip replacement is generally a safe and successful procedure that reduces pain and improves mobility.
In a healthy hip, smooth cartilage covers the ends of the femur (thighbone), as well as the socket (known as the acetabulum) in the pelvis into which the ball end of the femur fits. The cartilage acts as a cushion and allows the ball to glide easily inside the socket. The surrounding muscles support the joint, allowing it to move freely.
The most common cause of deterioration of the hip joint is osteoarthritis
. This condition causes the cartilage to become damaged and worn, allowing the bones within the joint to rub together. Movement of the joint causes the ball to grind into the socket, causing the bone ends to become roughened and irregular. This, together with the development of small breaks in the bone, causes pain and stiffness.
Other conditions that can damage the hip joint to the extent that it requires replacement include rheumatoid arthritis
(inflammatory arthritis), osteonecrosis (where poor blood supply to the ball portion of the hip causes it to weaken and deform) and hip fractures (particularly in the elderly).
People who might benefit from hip replacement surgery include those who have hip pain and/or stiffness that:
- Limits everyday activities, such as walking or bending
- Interferes with sleep
- Persists despite anti-inflammatory/pain medication, physical therapy, or walking supports.
An orthopaedic surgeon will assess the need for a hip replacement, taking into account medical history, lifestyle, physical examination (especially range of motion of the hip joint and strength of the supporting muscles), blood tests, and x-rays of the damaged hip(s). A hip replacement is a major operation and there are many things to consider before deciding upon surgery. As part of making a decision as to whether to opt for hip replacement surgery or not, the risks and benefits of the surgery should be discussed. The most common risks associated with hip joint replacement include:
- Anaesthetic risks (common to all surgery)
- Infection – both of the wound and of the artificial hip joint itself
- Development of blood clots
- Damage to the nerves and blood vessels surrounding the hip joint
- Fracture of healthy portions of the hip joint during surgery
- Dislocation of the artificial hip joint
- A change in the length of the leg that has been operated on.
A hip replacement operation can be performed using either local or general anaesthetic. This will be discussed with the anaesthetist prior to surgery and a decision made as to which anaesthetic is appropriate.
The surgery typically takes up to 2 hours to complete. The artificial hip joint (prosthesis) consists of a ball and stem (the femoral component) and a socket (the acetabular component). There are many different types of prosthesis made of various metals (eg: stainless steel, chrome, titanium), ceramics, plastic, or a combination of these. The two components of the prosthesis fit together to form a smooth joint. Some prostheses are “cemented” into place using special acrylic bone cement. Others do not require cement and rely on bone growing around the prosthesis to anchor them into place.
Surgery begins with an incision being made along the side of the hip joint that is to be replaced. The muscles that support the hip joint are detached and the damaged ball of the hip joint is cut from the top of the femur. The femoral component of the prosthesis is inserted into the femur and the acetabular component of the prosthesis is inserted into the prepared socket area in the pelvic bone. The artificial ball and socket are then fitted together and the surgeon reattaches the muscles to the top of the femur. Drainage tubes may be inserted to drain any fluid and/or blood from the new joint and the incision is then closed.
Antibiotics are usually given during and after the operation to prevent the development of infection in the new joint. A blood transfusion may also be required. This will be discussed by the surgeon prior to surgery.
There is an increased risk of developing blood clots in the legs after hip replacement surgery. Preventative measures may include:
- Early mobilisation: Sitting up and even trying to walk with crutches or a walker soon after surgery will be encouraged
- Wearing elastic compression stockings or inflatable leg coverings (compression boots) to help keep blood from pooling in the leg veins, which reduces the risk of clots forming
- Blood-thinning medication: Injected or oral blood-thinning drugs may be given after surgery.
A Hip Prosthesis
After surgery, nursing staff will closely monitor blood pressure, heart rate, breathing rate and oxygen levels. They will also monitor blood circulation in the leg involved.
A catheter will be in place to drain urine from the bladder. This usually stays in place for 24 – 48 hrs. Pain will be managed by administering pain relieving medications by tablet and via a drip in the hand or arm. Some people may have an infusion of pain relieving medication administered through a small tube into the back (an epidural). This is usually given for up to 48 hrs after surgery.
Fluid will be administered through a drip (intravenously) until the patient is eating and drinking well. Antibiotics will also be given via the drip for the first 24 – 48 hrs after surgery.
A hip prosthesis has a limited range of motion compared to a natural hip and special care will need to be taken until the soft tissue around the new hip joint has healed. Certain movements and positions must be avoided to reduce the chance of dislocation. The first six weeks after surgery is the highest risk time for dislocation of the new hip.
After surgery the healthcare team will work together to set movement guidelines and exercises that will assist with recovery. The success of the surgery depends on following these instructions while in hospital and carrying out the prescribed exercises when at home. In general, the following guidelines may be given for recovery when at home:
- Don’t cross the legs (including the ankles)
- Don’t bend down low
- Avoid lifting heavy objects
- Avoid forceful or jarring movement of the hip
- Avoid twisting movements of the hip
- Don’t lie on the operated side
- Always have a pillow between the legs when lying on the unoperated side
- Don’t stand for long periods
- Sit in a firm chair with arms (to assist getting in and out of the chair)
- Treat scratches and cuts promptly to decrease the chance of infection affecting the new joint
The time spent in hospital can vary but is usually 4 to 7 days. The health care team will make an ongoing assessment of recovery and will recommend when discharge home is appropriate. It is important to have support at home upon discharge. A part of the healthcare team’s assessment will be to discuss if special equipment needs to be installed to assist at home or if home help needs to be arranged.
Crutches will need to be used for up to six weeks after the operation. By six weeks, the majority of people should be able to return to most normal activities, including driving. Full recovery can take 3 to 6 months.
It is usual to see the surgeon 2 to 6 weeks after surgery to assess recovery. Long-term follow up may also be recommended in order to monitor the wear of the artificial joint. It may be that replacement of the artificial hip joint will be recommended if it wears significantly. In general, most hip replacements last at least 15 years if cared for and not subjected to excessive stress.
American Academy of Orthopaedic Surgeons (2015). Orthoinfo: Total hip replacement. Rosemont, IL: American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00377 [Accessed: 06/07/17]
Arthritis New Zealand (2015). Concerned? Talk with your doctor about your hip replacement (Web Page). Wellington: Arthritis New Zealand. https://www.arthritis.org.nz/hip-replacments/ [Accessed: 06/07/17]
Auckland Orthopaedic Practice (Date not stated). Patient Info: Total hip replacement (Web Page). Auckland: Auckland Orthopaedic Practice. http://www.aucklandorthopaedicpractice.co.nz/total-hip-replacement.html [Accessed: 06/07/17]
Mayo Clinic (2017). Hip replacement (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/tests-procedures/hip-replacement/home/ovc-20313778 [Accessed: 06/07/17]
NHS Choices (2017). Hip replacement (Web Page). Redditch: National Health Service (NHS)
England. http://www.nhs.uk/Conditions/Hip-replacement/Pages/Introduction.aspx [Accessed: 06/07/17]
Last Reviewed – July 2017