A total hip replacement is an operation to remove a damaged hip joint and replace it with artificial parts. The aim of the surgery is to relieve pain and restore function to the joint.
Hip replacement surgery is a common operation undertaken in New Zealand as planned (non-urgent) surgery in both public and private hospitals, typically involving a few days’ hospital stay.
Why have hip replacement surgery?
The most common reason for hip replacement surgery is osteoarthritis. This condition causes the cartilage, which covers the ends of the bones of the hip joint, to become damaged. This means the bones within the hip joint rub together, causing pain and stiffness.
Other conditions that may lead to hip replacement surgery include rheumatoid arthritis (inflammatory arthritis) and osteonecrosis (where poor blood supply to the ball portion of the hip causes it to weaken and deform).
People who might benefit from hip replacement surgery include those who have hip pain and/or stiffness that:
- Limits everyday activities, such as walking, bending, or rising from a seated position
- 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 the person’s medical history, lifestyle, physical examination (especially range of motion of the hip joint and strength of the supporting muscles), and x-rays or magnetic resonance imaging (MRI) scans.
Although most people who undergo hip replacement surgery are between the ages of 50 and 80 years, consideration for hip replacement surgery is based on a patient's pain and disability, not their age. A person also needs to be well enough to cope with both a major operation and the rehabilitation that is required afterwards.
A hip replacement is a major operation and there are many things to consider before deciding upon surgery. The risks and benefits of the surgery should be discussed with the surgeon. The most common risks include:
- Anaesthetic risks (common to all surgery)
- Infection — both of the wound and of the artificial hip joint itself
- Development of blood clots in one of the deep veins of the legs (deep vein thrombosis)
- 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.
The artificial hip joint (prosthesis) consists of a ball and stem, and a socket. These can be made of metal, 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 bone cement. Others do not require cement and rely on bone growing around the prosthesis to anchor them into place.
Procedures may differ depending on the person’s condition and the surgeon’s practices, and can be performed using either spinal or general anaesthetic. The muscles that support the hip joint are detached and the damaged parts of the thighbone (femur) and hip socket (acetabulum) removed.
The ball and stem component of the prosthesis is inserted into the thighbone and the socket component of the prosthesis is inserted into the pelvic bone. The artificial ball and socket are then fitted together, and the surgeon reattaches the muscles to the top of the thighbone.
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.
Antibiotics are usually given during and after the operation to prevent the development of infection in the new joint. Pain will be managed by administering pain-relieving medications by tablet and/or via a drip in the hand or arm.
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 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.
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.
Crutches or a walking frame may need to be used for up to six weeks after the operation. After six weeks, most people should be able to resume normal activities, including driving, but this will depend on the healthcare team’s instructions. Full recovery may take several months.
Outcomes of surgery
The aim of hip replacement surgery is to enable a person to resume normal activities of daily living without pain and stiffness. Examples of these types of activities are climbing stairs, walking, swimming, playing golf, light hiking, cycling, and dancing.
American Academy of Orthopaedic Surgeons (2020). Orthoinfo: Total hip replacement. Rosemont, IL: American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/treatment/total-hip-replacement/ [Accessed: 30/6/21]
Mayo Clinic (2020). Hip replacement (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/tests-procedures/hip-replacement/about/pac-20385042 [Accessed: 30/6/21]
Ministry of Health (date not stated). Total hip replacement: a guide for patients (PDF pamphlet). Wellington: New Zealand Ministry of Health. https://www.health.govt.nz/system/files/documents/pages/guide-hip-replacement-surgery.pdf
NHS (2019). Hip replacement (Web Page). Redditch: National Health Service (NHS) England. https://www.nhs.uk/conditions/hip-replacement/ [Accessed: 30/6/21]
Last Reviewed – June 2021