The majority of hip replacements do not require revision operations. The statistics show that following 15 years, hip revision operation stands at 9.6% (varies from 4.3 to 12.4%, depending on prosthesis used). This highlights the fact that total hip replacement surgery is a very successful operation and only a small percentage fail and require revision operations.
The Australian Joint Replacement Registry is managed by the Australian Orthopaedic Association. This registry which was established in 1999 and became fully national in 2002, collects data on all joint replacements performed in Australia. The purpose of the registry is to improve and maintain the quality of care for the individual. It also identifies the prostheses that have a high revision rate. This gives the surgeon a more informed choice on the chosen prostheses and so has reduced the risk of revision.
Indications for revision hip replacement
Loosening / Osteolysis
The commonest cause of failure of hip replacements is due to wear and tear of the prosthesis. The debris from the worn joint replacement surfaces may initiate an immune response in the surrounding tissues. This immune response causes damage to the surrounding bone and soft tissues. This damage may loosen the prosthesis- whether it is the femoral or acetabular component or both. The patient usually presents with a painful hip-particularly with activity. The percentage of revision hip replacements has declined from its peak of 12.9% in 2003 to 9.6% in 2015.
Infection can occur soon after surgery or months to years later. The early infections are caused by bacteria contaminating the prosthesis at the time of surgery but may not be evident for weeks or months after the operation. Most patient with deep infection usually present with painful hip.
Late infections are usually caused by bacteria seeding the joint having spread from an infection elsewhere in the body. Common sources are from cellulitis, bacterial urinary and dental infections, (hence the importance of early treatment of bacterial infections and prophylactic use of antibiotics during significant surgical or dental procedures).
Occasionally the infection can be managed with washing out the joint several times under anaesthetic, together with the administration of high-dose intravenous antibiotics.
When this is unsuccessful, a two-staged procedure is required. Firstly, the original prosthesis must be removed as well as any surrounding infected tissue. An antibiotic impregnated spacer is put into the joint to maintain the length of the leg. High dose intravenous antibiotics are used to bring the infection under control. Once the infection is eradicated, a second stage revision hip is performed. This is usually done 3 months later.
The highest risk of dislocation occurs in the first 6 weeks hence the importance of guided rehabilitation. The dislocation of the hip replacement occurs when the prosthetic femoral head slips out of the acetabular cup. This dislocation caused severe pain and requires urgent ambulance transfer to the Emergency Department. Usually the hip is relocated under anaesthetic and usually does not dislocate again. However, if the hip continues to dislocate, a revision replacement will be required.
Hip fractures usually follow a fall and, with their increasing frailty, the elderly are more prone to fall. Fractures of the femur (hip bone) and occasionally the acetabulum, may occur close to the prosthesis. This can be managed with internal fixation with plates and wires but sometimes requires a revised hip replacement.
Peri-operative patient education
Once it has been established that a revision hip replacement is necessary, Dr Lane will discuss the surgical options in depth. The complexity of the operation varies with the individual requirements. It may take further consultation to discuss the procedure with the patient and to clarify any issues or concerns. The patient will be given a full explanation of the revision procedure, expected recovery time and eventual outcome.
After a decision is made to proceed with the revision hip replacement, Dr Lane may refer the patient to a specialist physician so optimise the patient’s medical condition pre-operatively. The patient may also be seen by the anaesthetist in a pre-operative clinic.
The patient will able to attend a pre-operative education session at either the Sunshine Coast private hospital in Buderim, or at the Sunshine Coast University Private Hospital at Birtinya. This is supervised by experienced nurses and physiotherapists. The more knowledge the patient has of the upcoming operation the smoother the recovery
The patient is admitted the day prior to surgery. Pre-operative investigations are performed which include blood tests, cross matching for blood, ECG, CXR and urinary analysis.The admission, pre-operative and anaesthetic course is similar to the primary hip replacement course and discussed in “Total Hip Replacement”.
Revision hip surgery varies in depth of complexity depending on whether prosthesis is loosened, worn, infected or involved with peri-prosthetic fracture. There is myriad of surgical techniques which are used to remove the existing prosthetic hip joint and any diseased bone or tissue, to prepare and support the bone for a new prosthetic joint. This is determined on a case by case basis. Given the complicated nature of the operation, theatre is equipped with an extensive variety of instruments to undertake even the worst case scenario. The type of hip prosthesis inserted will be determined at the time of surgery and chosen to give a stable joint with good mobility to achieve the best outcome. A urinary catheter is inserted before hip surgery begins, to monitor urine flow during and after the procedure. Intravenous antibiotics given prophylactically. Once surgery is complete, a reperfusion drain is inserted, the wound closed with staples and sterile dressing applied. At the end of the operation you will be rolled on your back with a triangular pillow placed between your legs to maintain leg position.
Surgical options may include:
- Simple exchange of femoral head component and acetabular liner. This usually results from excessive wear of the bearing surfaces but the remaining prosthesis remains well fixed to bone.
- Removal of acetabular and/or femoral component. This can be a very challenging procedure. It may require cutting the femur (trochanteric osteotomy) to remove all the femoral components and cement before the new prosthesis can be inserted.
- Insertion of new prosthesis. The femoral stem usually needs to be larger and longer than the original and will need to be held with wires and /or plate to splint the deficit in the femoral trochanter. If the acetabular component needs to be revised then may have augments that fill the space created from the damaged bone.
- Bone graft. Allograft bone grafting is often used to make up the damaged bone. It is obtained from the bone bank that stores bone taken from organ donors and is tested in a similar manner to blood to make sure it is free of communicable diseases.
- A variety of bearing surfaces are available in surgery and designed to minimise post-operative dislocation.
Infected cases need a 2- stage procedure:
- Stage 1 involves removal of all existing prosthesis and infected soft tissue. At this time, a cement spacer is usually inserted, impregnated with antibiotics.
- Stage 2 involves removal of the spacer and insertion of revision prosthesis. This may occur up to 3 months following stage 1.
The surgery lasts between 2 and 12 hours and depends on the complexity and difficulty of the operation.
The patient may go to the Intensive-care Unit for close monitoring post-operatively. A blood transfusion may be required. The majority of patients will be mobilised under supervision of a physiotherapist. Rehabilitation will be determined and modified by the surgical procedures performed in the operation. The stay in hospital can vary from 3 –10 day depending on the extent of surgery. Some patients, particularly the elderly, will be transferred to a rehabilitation Unit or Hospital.
It is important to continue to use crutches or walking aids when you get home.
The complexity of your surgery will determine your rehabilitation and you will be guided by Dr Lane and the physiotherapist. In some cases, there will be modified weight bearing for up to 3 months. The blue nurses will remove the wound staples 2 weeks after the surgery.
The risk of hip dislocation is highest in the first 3 months after surgery. It is important that you are aware of the risks to your hip and follow hip precautions as described by your physiotherapist. An occupational therapist may also visit your home to ensure aids are available to help with your rehabilitation. Precautions include:
Use a seat raise for the first 6 weeks and avoid flexing the hip to more than 90 degrees.
- Do not sit in chairs without arms.
- Do not pivot or twist on the operated leg.
- Do not cross your legs or turn your knees inward.
- You will need to sleep flat on your back for 6 weeks and not your side.
- Do not bend to pick anything up.
- Do not lie without a pillow between your legs.
- Do not sit in a bath.
You are unable to drive for 6 weeks and should to avoid the risk of trauma to the surgical repair.
You will be reviewed by Dr Lane 6 weeks following the surgery and you can get into a car for the visit.
Once you have the revised hip replacement it is important that you look after it. Of course, it is encouraged that you return to an active normal life with regular exercise but this should be tapered to care for your new hip. Running and jumping should be avoided as this would potentially stress the hip too much, wear it down and so shorten its longevity. Activities such as walking, golf, swimming, cycling, lawn bowls are recommended.
It is important to treat any bacterial infection such as urinary tract infections, diverticulitis, dental infections aggressively as this would deter ‘seeding’ of the infection from these potentially blood-borne infections to the hip. All invasive surgical procedures and dental work should be covered with prophylactic antibiotics. If a hip replacement becomes infected the consequences can be dire.
General risks associated with Anaesthetic
During surgery, your body is stressed and any pre-existing conditions such as heart, respiratory, diabetes and circulatory conditions may worsen.
- Death (rare).
- Heart Attack.
- Pneumonia. Small areas of the lung can collapse following surgery and become infected requiring antibiotics and physiotherapy.
- Short term confusion.
- Blood clots (Deep venous Thrombosis). Measures are taken to minimise this complication, including wearing TED stockings, foot pumps. Aspirin or heparin-like substance is used to thin the blood. Early mobilisation is also encouraged. While all measures are taken to avoid this complication, deep venous thrombosis can still occur in the legs and sometimes travels to the lungs causing a pulmonary embolus which potentially can cause death.
- Prostate and bladder problems can be exacerbated by the surgery. Routinely a catheter is inserted into the bladder to avoid these complications. The catheter is removed once comfortable and mobile.
Superficial infection shortly after the operation is an uncommon complication that usually responds to antibiotics. Infection after hip replacement can occur at any time and so it is important to be vigilant to the risk of infection. It may require long term systemic antibiotics and further surgery. Revision of hip replacement but may require removal of prosthetic hip joint and then the patient is left with a short painful leg.
A hip can dislocate and it is more at risk in the first three months. Measures are taken to minimise the risk of dislocation following surgery. The hip dislocation acute pain and inability to walk. The hip can usually be relocated manually in the operating theatre without the need for open surgery. The risk of dislocation is greater in revision hip surgery.
Leg Length Discrepancy
Every effort is taken to maintain the legs at equal lengths. The aim if hip replacement is to and give a pain-free, mobile, stable hip and sometimes there is a trade-off between this and a slightly lengthened leg.
This is a rare complication of hip replacement as during the operation every endeavour is made to protect the underling nerves and major vessels. It can lead to loss of sensation over the foot and ankle and weakness such as foot drop.
Loosening of the prosthesis
In the first few months following hip revision, loosening of the prosthesis may be due to failure of the implant to bind to bone despite measures such as bone grafting and prosthetic augments used.
The risk of complication is increased in smokers, diabetics, obese patients, patients with advanced age and who are generally frail, and those with other multiple medical conditions.