Osteoarthritis of the hip joint is a common condition and can lead to severe pain, stiffness and disability. The total hip replacement, also called hip” arthroplasty”, has transformed the treatment of this condition with resultant excellent relief of pain and restoration of mobility in a very high percentage of cases.
A total hip replacement involves the removal of the worn- out head of the thigh bone (femur) and replacing it with a stemmed femoral prosthesis and replacing the worn- out socket (acetabulum) with a shell and liner.
Over 95% of patients are delighted with the outcome following joint replacement surgery.
The patient’s understanding of the pre-operative events, surgical procedure and rehabilitation process are can lead to a less stressful and smoother recovery.
Indications for hip replacement
Patients eligible for this surgery have moderate to severe arthritis in the hip, including osteoarthritis and rheumatoid arthritis, that causes pain and interferes with daily activities. For example:
- Walking, going upstairs and bending to get in and out of chairs is painful.
- Moderate to severe pain that occurs at rest and affects sleep.
- Hip degeneration can also lead to stiffness of the joint which limits range of movement and may cause a limp.
- Symptoms are not relieved with modifications of daily activities or with analgesia such as non-steroid anti-inflammatory drugs.
Peri-operative Patient Education
At the time of consultation, Dr Lane will give a full explanation of what is involved in a joint replacement operation, expected recovery and eventual outcome.
The following guide further informs the patient. Educational leaflets supplied by the Australian Orthopaedic Association are also supplied. However, if there are any further concerns, the staff at Lake Kawana Specialist Centre are happy to take calls and if needed, a further explanation is encouraged with either nursing staff, anaesthetist or Dr Lane.
If you have significant pre-existing medical conditions you may be reviewed by further specialists such as cardiologist or other specialised physicians, and anaesthetist prior to surgery.
The patient is asked to attend a pre-operative education session at hospital, (Sunshine Coast Private Hospital or the Sunshine Coast University Hospital). This is conducted by experienced nurses and Physiotherapist. Awareness of the upcoming procedure makes the patient less fearful and anxious about the event. This increased knowledge reduces post-operative pain and leads to a less stressful recovery.
Anti-inflammatory drugs such as Feldene, Naprosyn, Nurofen, Brufen, Ibuprofen, Indocid, Voltaren, Mobic and Celebrex should be stopped 5 days before surgery. These drugs may increase the risk of bleeding. Aspirin or other blood thinning drug usage prior to the surgery should be discussed with Dr Lane as this would depend on the patients underlying medical condition. The leg about to be operated on should be free of cuts, scratches and sores as this can increase the risk of infection. If there is any damaged skin on the leg to be operated on, then it is highly likely your operation will be postponed until healed. The patient is encouraged not to smoke prior to the operation to reduce the risk of thrombosis (DVT). Dr Lane will review you a couple of days before the operation to make sure there are no problems. At the pre-admission clinic, you will be given an anti-septic skin wash to use in the shower the day before admission. Pre-operative investigations are performed which include blood tests, cross matching for blood, ECG, CXR and urinalysis.
Depending on the time of your operation, you may be admitted the day before or early in the morning of the procedure. Your expected hospital stay would be between 3 and 7 days.
You should not eat or drink 6 hours before your surgery.
Bring to hospital:
- Personal effects such as Pyjamas, slippers, dressing gown and toiletries.
- Current medication.
- Relevant X-rays.
- Medicare and Private Health Care Card.
You will be seen at the Admissions Area and taken to the Ward. Before going surgery:
- You will have a shower with an antiseptic solution.
- Theatre gowns and disposable underwear given to wear.
- The thigh will be inspected by the nursing staff, an anti-septic applied to the skin and the thigh then dressed with a sterile drape.
- The other leg will have a TED stocking applied to reduce the risk of thrombosis following surgery.
You will be taken to the theatre complex by the nursing staff and then into the anaesthetic bay next to the operating room. There you will meet Dr Lane and your anaesthetist.
The anaesthetist will taper your anaesthetic to suit your needs. This may involve a general anaesthetic (when you are completely asleep) or a local regional block (spinal or epidural using a needle into the lower back) which numbs the legs, used with twilight sedation. Post-operatively, you will receive narcotic type drugs for pain relief which may be delivered by PCA (Patient Controlled Analgesia) combined with other pain killers and anti-inflammatory medication. Prophylactic intravenous antibiotics are given prior to surgery.
Prior surgery you will also receive intravenous tranexamic acid. This has been shown to reduce bleeding during the operation and reduces the need for allogenic blood transfusion. Tranexamic acid is ab anti-fibrinolytic or "blood clot stabiliser " whose mechanism of action reduced bleeding.
- A catheter will be inserted into your bladder prior to the operation to avoid any problems with the bladder post-operatively.
- You will be laid on your side and held in position with supports attached to side of theatre bed.
- The thigh and leg are prepared with ant- septic solution and you will be covered in sterile drapes exposing only the operative site.
- X-rays are displayed in theatre for reference by Dr Lane throughout the operation.
- A curved longitudinal incision is made over the lateral aspect of the hip. The incision usually measures 10 to 20 cm and is determined by the size of the patient, underlying pathology and the size of the prosthesis. Great care is used to protect the major blood vessels and nerves that surround the hip. The soft tissue envelope surrounding the hip is carefully retracted, muscles gently split and capsule opened.
- The diseased hip is then dislocated and the worn out femoral head removed. The socket is then prepared using a special drill to achieve a hemispherical field. Any bony spurs will be removed from the margins of the acetabulum and bone cysts (apparent -rays and visually) will be filled with bone from the existed femoral head at that time. The prosthetic socket and liner are then inserted- usually un-cemented but can be cemented and determined by the quality of the bone. The femoral shaft is then prepared using increasing sized stems to allow entry of proposed femoral prosthesis. The stem is then cemented into the femur. Trial femoral heads are inserted onto the stem and hip relocated to determine the exact sizing to achieve stability, good range of movement of the joint and appropriate leg length. Once femoral head determined, the femoral head prosthesis is located onto the stem and hip relocated. At this point a reperfusion drain is inserted around the joint, the capsule and different muscle layers repaired and skin closed with staples. A sterile dressing is then applied. The reperfusion drain allows blood lost to be transfused back into the patient post-operatively.
- At the end of the operation you are then rolled back onto your back and have the anaesthetist will withdraw the anaesthetic agents and waken you up. A triangular pillow will be inserted between your legs to maintain position. You will then be transferred to the recovery ward with an intravenous drip and oxygen mask secured.
Dr Lane uses a cemented highly polished doubled tapered stainless- steel stem for his femoral shaft component – this is the iconic “Exeter stem”. He uses a highly polished cobalt femoral head. The acetabular component includes a shell made up of cobalt chrome with a titanium and hydroxyapatite outer coat which encourages bony in-growth. Dr Lane may very occasionally cement the acetabular component into the socket but this is determined by the patient’s age and bone stock. He uses a polyethylene liner but very occasionally this may be ceramic.
These prosthetic components have consistently shown to have excellent long-term survival worldwide
You will be wheeled into recovery on your bed. There your vital signs will be monitored by the nurse, as well as the sensation and circulation to your lower legs. When you are awake and observations are stable, you will be transferred to the Ward.
- Until you are able to eat and drink, an intravenous fluid line will remain keeping you well hydrated.
- Blood is taken to determine whether you need further blood transfusion. The hip drain is removed the next day.
- Below knee TED stockings will be fitted to both legs and foot pumps applied to the feet. This improves the circulation in the legs with the addition of low dose aspirin or other blood-thinners reduces the risk of blood clots. Aspirin is continued for 6 weeks post-operatively.
- Your usual medication is given to you.
- Intravenous antibiotics will continue for 24 hours
- The triangular pillow will be placed between your legs while in bed to maintain a good position and reduce the risk of hip dislocation.
- The anaesthetist will keep a closely monitor your pain relief. You will receive morphine-like pain relief which may be delivered by PCA (patient controlled analgesia) which allows the patient to titrate the pain killer intravenously. You will also receive a combination of other painkillers and anti-inflammatory drugs. Every effort is made to keep you comfortable and relatively pain free.
- An X-ray of your hip will be taken post-operatively to check the position of your hip. Blood levels checked the following day.
- The majority of patients will be asked to walk with assistance on the same day as the operation with full weight bearing. You will be supervised by the physiotherapist and nursing staff. Early mobility is encouraged as it reduced the risk of blood clots and improves the strength in the hip muscles.
- You will be given a number of hip exercises by the Physiotherapist to do over the next few days to get you safely back on your feet.
- Once you can safely walk 30 metres with crutches, get in and out of bed, access the toilet and shower room and get up and down stairs, then you are ready to go home.
- You will either by discharged home by ambulance or if older and with lack support at home, then to a rehabilitation unit for a further 7 to 10 days.
It is important to continue to use crutches or walking aids when you get home but it is usual to come off these aids once you have little pain and good strength in your legs. Most people come off the crutches 3 – 5 weeks following the surgery. 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 only go into the car in event of an emergency 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 new 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 and social tennis 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 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.
Which approach to use in hip replacements?
There are three main types of surgical approaches in hip replacement surgery.
- Posterior approach.
- Anterior approach.
- Lateral approach.
“The Arthroplasty Society of Australia Position Statement on Surgical Approach of Hip Arthroplasty”, October 2016
There are multiple ways to approach a hip joint while performing hip replacements. Several of these approaches have a long history of safe use in surgeons who are well trained in orthopaedic surgery.
- There is no published level 1 (highest level) scientific evidence that endorses one surgical approach over the other.
- The different surgical approaches have advantages and disadvantages which may be patient specific. No surgical approach is without risk.
- Surgical approach has little influence on results in the short or long term.
- A long lasting and successful result can be achieved with a total hip replacement done through any number of surgical approaches.
- Patients are well advised to allow the surgeon to decide which approach is most appropriate in their case.
- Surgeons should tell patients which works best in their hands but should not claim an advantage over approaches used by other surgeons.
This is the approach used in 85% of hip replacements in Australia and is the most common approach worldwide. The incision is placed along the buttock and the muscle behind the hip is split to allow access to the hip joint. If there are any surgical problems, the incision can be extended- which is an important aspect to this approach.
One of the most important risks of hip replacement is hip dislocation. This usually occurs in the seated position and the hip dislocates posteriorly through the tissues that have been operated on. The risk of dislocation in the posterior approach can be significantly reduced by limiting the tissue division to give adequate exposure and a strong capsular repair. This incision can be extended in any direction if needed with no fear of damaging nerves that supply the hip abductors.
It is for this reason that Dr Lane prefers the posterior approach.
The Anterior Approach or “Minimally Invasive Direct Anterior Hip Replacement Surgery” as it is often marketed, has been performed in Europe for more than 50 years and was introduced to Australia 5 to 8 years ago. It is currently receiving a lot of media attention.
The advocates of the anterior approach claim that as the muscle is not cut at the time of surgery but merely split, this reduces post-operative pain leading to an early discharge. Pain is not a great issue in hip replacement surgery and rarely delays discharge. It is also said that the dislocation rate is lower than the traditional method, allowing for early return to work, leisure pursuits and driving. However, at this stage, there is currently no scientific evidence to support these claims.
The anterior approach also uses a smaller incision. The main disadvantage to this would be establishing a good view. Also, it is very difficult to extend the incision if there are any unforeseen operative difficulties e.g. bleeding, bony spurs, without possible damage to the nearby nerves supplying the abductor muscles of the hip.
The anterior approach would not be indicated in those who are markedly obese, very muscular, have complex anatomical problems and have a severe protrusion as it would be very difficult to gain an adequate view.
Direct lateral approach
This is a common approach. The incision is slightly forward of the hip joint and has a low dislocation rate. It involves cutting through the abductor muscles which potentially can lead to a limp which is difficult to address. There is an increased risk of heterotopic bone formation using this approach which causes calcification of the tissues, reduces hip movement and can be painful.
There was a trend about 10 years ago, to perform to use a "mini-invasive" approach. Some surgeons were attempting hip replacements with as little as 6 cm incisions. However, the key to good outcome is the exact placement of the hip components. Most surgeons realised that the small incisions did not give adequate access to achieve accurate placement of the hip components which led to an unacceptable high complication rate.
Types of Prosthesis
There are several different materials used in the total hip replacement. The bearing surface describes what the actual “ball and socket” is made of.
The socket composes of two parts. A metal shell is inserted into the socket. It has a roughened surface which encourages bone growth into the shell. A liner is then placed into the shell which is usually made of low friction, highly cross-linked polyethylene.
A tapered metal, stem is inserted into the femur. It is usually cemented with an acrylic compound – polymethylmethacrylate or PMMA. A cemented femoral component will suit a large percentage of patients requiring hip replacement. If the patient has a narrow femur, is young and active, an un-cemented femoral stem may be used. This uses a titanium stem which is rough to encourage bone growth on the surface.
A modular head is then inserted on top of stem.
There are 3 alternative bearing surfaces:
Metal on Polyethylene
Newer plastics such as highly cross-linked polyethylene have extremely low wear rates. It is the most common plastic used at present and the Australian Joint Registry has shown significant reduction in the revision rate using this newer material.
Metal on Metal
This type of bearing surface was popular in the 1980 and 90s in younger patients. The wear rate of most metal on metal was very low and it was hoped to last 30 years or more. The disadvantages of this bearing are that it releases fine metal particles into the blood stream and as it is a heavy metal such as cobalt, it could potentially cause kidney and heart damage as well as chromosomal changes.
Ceramic on Ceramic
This bearing surface has a very low wear rate. It is a bio-inert substance. It can be somewhat brittle and there is a small chance of fracture of the ceramic component which requires urgent hip revision surgery.
General risks of 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 patient is left with a short painful leg.
A hip can dislocate and it is more at risk in the first three months but potentially remains a lifelong risk. There is no difference in the dislocation rate in whatever surgical approach was used. 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.
Leg Length Discrepancy
Every effort is taken to maintain the legs at equal lengths. The aim of hip replacement is to 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 Hip Replacement
Over 95% of patients who have a hip replacement have excellent relief of pain with improved mobility. Most patients never require a revision of the hip replacement. The major cause for hip revision is wear and tear of the ball and socket or loosening of the prosthesis. This will be discussed more fully in the ‘Hip Revision Hip Surgery ‘section. According to the Australian Association National Joint Registry, currently the best 5 prosthesis combinations have a cumulative percentage revision of less than 5 % at 10 years.
Fracture of femur or acetabulum
Very occasionally, the femur or socket may fracture during surgery. Rarely the fracture will require further surgery. This is often recognised and treated at the time of surgery and may require a modified rehabilitation.
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.