Total Hip Replacement (THR)

Total hip replacement (also known as total hip arthroplasty), which was first performed in 1960, is a surgical procedure in which the damaged cartilage and bone is removed from the hip joint and replaced with artificial components. Since 1960, improvements in joint replacement surgical techniques and technology have greatly increased the effectiveness of total hip replacement, and it is one of the most successful operations in all of medicine, with satisfaction rates reported of about 95%. Hip replacement surgery is a relatively safe procedure that can predictably relieve pain, increase motion, and help you return to enjoying normal, everyday activities.

Anatomy

The hip is one of the body's largest weight-bearing joints. It is a ball-and-socket joint, with the socket formed by the acetabulum (which is part of the large pelvis bone) and the ball is the femoral head (which is the upper end of the femur or thighbone). The bone surfaces of the ball and socket are covered with articular (hyaline) cartilage, a smooth tissue that cushions the ends of the bones and enables them to move smoothly. A thin tissue called synovial membrane surrounds the hip joint, and in a healthy hip, this membrane makes a small amount of fluid that lubricates the cartilage and eliminates almost all friction during hip movements. Bands of tissue called ligaments as well as the hip capsule connect the ball to the socket and provide stability to the joint.

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Normal hip anatomy

Causes of Hip Arthritis

Any process that can damage the protective smooth layer of joint surface cartilage may lead to osteoarthritis, causing extreme pain and difficulty in performing daily activities. The exact cause of osteoarthritis is not known, and there is currently no medical cure. All non-surgical (conservative) therapies aim to manage the disease and relieve symptoms. Joint replacement surgery is the only real solution for symptomatic end-stage arthritis.  

There are a number of diseases and conditions that may cause damage to the articular cartilage resulting in arthritis, and these include:

• Osteoarthritis – This is the most common form of hip arthritis. It is an age-related "wear and tear" type of arthritis, and usually occurs in people 50 years of age and older and often in individuals with a family history of arthritis. Over time, the joint cartilage cushioning the bones of the hip becomes thinner or completely absent exposing bare bone. In addition, the bones become thicker around the edges of the joint and may form bony “spurs” (osteophytes). These factors can cause pain, swelling and restriction in hip movement.
• Inflammation of the joint (inflammatory arthritis – the commonest being rheumatoid arthritis) – Rheumatoid arthritis is an autoimmune disease in which the tissue lining the joint (synovial membrane) becomes inflamed and thickened with production of excessive joint fluid containing destructive enzymes and factors. This chronic inflammation can damage the cartilage, leading to pain and stiffness. 
• Post-traumatic arthritis - This results from a hip injury (such as a previous labral tear or chondral injury), fracture, or traumatic dislocation.
• Avascular necrosis – In avascular necrosis (also commonly referred to as "osteonecrosis"), the blood supply to the head of the femur is lost or restricted, and may cause death of the bone with collapse of the hip joint surface, and secondary arthritis develops. An injury to the hip, such as a dislocation or fracture, may limit the blood supply to the femoral head. And there are a number of specific associated factors (e.g. excess alcohol or longer term use of steroids) and diseases that will also precipitate avascular necrosis (see the section on Hip Avascular Necrosis).
• Childhood hip disease - Some infants and children have hip problems. Even though the problems appear to have been successfully treated during childhood, they may still cause arthritis later on in life. This happens because the hip may not grow normally, and the joint surfaces are affected by the changes in the patterns of force applied. Some of these conditions include developmental hip dysplasia (DDH), Perthes disease, or slipped capital femoral epiphysis (where the round growing part of the femoral head slides of the neck of the femur).
• Increased body weight.
• Repetitive overuse – Probably secondary to recurrent labral or chondral surface injury.
• Joint infection (septic arthritis) – The bacterial infection leads to rapid joint surface cartilage destruction.  This is an orthopaedic emergency.  Delay in management will inevitably cause irreversible joint damage and secondary arthritis, requiring hip replacement once the area has been sterilised (infection eradicated).
• Connective tissue disorders (such as systemic lupus erythematosus).

Indications for Total Hip Replacement

Total hip replacement surgery is commonly indicated for severe osteoarthritis of the hip that has failed to respond to non-surgical treatments. 

A number of diseases and conditions can cause damage to the articular (joint surface) cartilage that result in hip pain and disability, with osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis being the most common.

In hip osteoarthritis, the smooth articular cartilage wears away and becomes frayed and rough, with secondary joint space narrowing, formation of bone spurs.

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Total hip replacement may be advised if you have:

• Hip pain that limits everyday activities, such as walking or bending
• Hip pain that continues while resting, either day or night
• Stiffness in a hip that limits the ability to move or lift the leg
• Inadequate pain relief from conservative (non-surgical) treatments including anti-inflammatory drugs, physical therapy, or walking supports

Recommendations for surgery are based on a patient's pain and disability, and not their age. Most patients who undergo total hip replacement are aged 50 to 80, but each patient must be individually evaluated. Total hip replacements have been performed successfully at all ages, from the young teenager with juvenile chronic arthritis to the elderly patient with degenerative osteoarthritis.

With current generation technology, techniques and implants, the total hip prosthesis should last over 20 years.

Description

During a total hip replacement (also called total hip arthroplasty), the damaged bone and cartilage is removed and replaced with prosthetic (artificial) components. The steps involved include:

• The damaged femoral head is removed and replaced with a metal stem that is inserted into the hollow centre (marrow in the canal) of the femur. The femoral stem may be either cemented or "press fit" (uncemented) into the bone.
• A metal or ceramic ball is impacted on the upper part of the stem. This ball acts as a substitute for the damaged femoral head that was removed.
• The damaged cartilage surface of the socket (acetabulum) is removed and replaced with a metal socket (shell). Screws or cement (cement is usually only used with all-plastic sockets) are sometimes used to hold the socket in place.
• A plastic, ceramic, or metal spacer (liner) is inserted into the acetabular shell to allow for a smooth gliding surface.

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(Left) The individual components of a total hip replacement. (Centre) The components merged into an implant. (Right) The implant as it fits into the hip.

The bearing surfaces where the ball and socket meet are the most important consideration for a hip replacement, as this will provide a smooth gliding surface that allows the joint to move easily without pain, and consideration must be given to the longevity of this articulation.  The bearing surfaces may be metal on plastic, ceramic on plastic, or ceramic on ceramic (significantly less metal on metal is now used following a number of recent implant recalls due to the production in some patients of metal wear particles, called “metallosis” which may lead to implant failure or pain due to bone loss bursa formation,  or tendon rupture around the hip replacement, though it is still used in hip resurfacing procedures).  

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Each bearing choice has its own unique advantages and disadvantages, though ceramic on ceramic is the superior choice in terms of longevity (it is less forgiving during implantation and must be positioned accurately to avoid any issues).

Since 1998, A/Prof Woodgate has been using hard-on-hard ceramic bearings in the majority of patients, along with uncemented components for the socket and stem, which have special coatings that encourage the patient’s bone to bond to the metal (this is known as osseointegration).  The need to revise ceramic bearing hips for wear or bone reaction/loss is extremely low, especially since the introduction of the newer ceramic, Biolox Delta, in about 2013, and there have been no reports of ceramic fracture/failure since.  This ceramic has extremely low friction shown in multiple studies and wear generation suggests a lifespan of approximately 30 years.

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History and Progressive Development of Hip Replacement

Total Hip Replacement (THR) is considered one of the most significant medical advances that occurred in the 20th century.

The American surgeon, Dr. Austin T. Moore (1899–1963), performed the first metallic hip replacement surgery at Columbia Hospital, South Carolina, on September 28, 1940. The original prosthesis he designed was a proximal femoral replacement, with a large fixed head made of the cobalt-chrome alloy, Vitallium.  In 1953, an English Surgeon, Dr George McKee was the first to utilise a metal-on-metal articulating prosthesis.  Hip replacement was progressed and pioneered mostly by the advances introduced by Sir John Charnley in the early 1960’s. His original implant was considered the “gold standard” in total hip replacement for many years – it was a simple stainless steel stem and plastic shell that were cemented into the bones using a technique that involved removing the gluteal tendons and bone and subsequently rewiring them.

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There have been significant advances since then, both in the materials utilized for the separate components as well as in the surgical techniques including rehabilitation.

Diagnosis and Orthopaedic Evaluation

The diagnosis and evaluation of hip arthritis, for which total hip replacement may be recommended, is based on several components:

• A thorough and detailed medical history – to obtain information about your general health and about the extent of your hip pain and ability to function.  
• A physical examination - This will assess knee range of motion, stability, strength, and overall lower leg alignment.
• X-rays - These images help to determine the extent of damage and deformity in your hip, and typically show narrowing of the joint space.

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(Left) In this x-ray of a normal hip, the space between the ball and socket indicates healthy cartilage. (Right) This x-ray of an arthritic hip shows severe loss of joint space (bone on bone).

• Other tests - Occasionally blood tests, or advanced imaging studies such as a magnetic resonance imaging (MRI) scan, may be needed to determine the condition of the bone and soft tissues of your hip.
• There will be a full discussion about the surgical procedure, including realistic expectations and outcomes, potential risks and complications, as well as any role for non-surgical treatments or prehab (pre-surgery exercise or rehabilitation). You should also provide a full list of medications (prescribed, non-prescription, herbal, and blood thinning) that you take, and timing for stopping any of these will be advised as necessary.

Realistic Expectations for Total Hip Replacement

Over 90% of people who have total hip replacement surgery experience a dramatic reduction of hip pain and a significant improvement in the ability to perform common activities of daily living. In fact, overall satisfaction rates are reported at about 95%, despite the initial painful nature of the procedure. Total hip replacement will not allow you to do more than you could before you developed arthritis, that is, the hip is NOT “bionic”.

With normal use and activity, every hip replacement implant inevitably begins to wear, though clearly with a hard-on-hard ceramic articulation this will occur extremely slowly. Excessive activity or weight may possibly accelerate this normal wear and may cause the hip replacement to loosen or become painful. High-impact activities such as running, jogging, jumping, or other high-impact sports should be restricted or avoided for the rest of your life after surgery. Realistic activities following total hip replacement include unlimited walking, swimming, golf, driving, light hiking, biking, ballroom dancing, and other low-impact sports. 

Risks and Complications

The complication rate following total hip replacement is low, with significant complications, such as infection, occurring in fewer than 1-2% of patients. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. When these complications occur, they can prolong or limit full recovery.

Possible risks and complications associated with total hip replacement surgery include:

• Infection – This may occur in the superficial wound or deep around the prosthesis. It may happen while in the hospital or after you go home, and may even occur years later. Minor infections in the wound area are generally treated with antibiotics. Major or deep infections may require more surgery and including washout or removal of the prosthesis. Any infection in your body can spread to your joint replacement. The incidence of deep infection is reported to occur in 1-1.5% of cases, but this has been reported to be lower in high volume surgeons.

• Blood clots (deep vein thrombosis) - Blood clots in the leg veins are one of the most common complications of hip replacement surgery, and have been reported as high as 25% in some series (A/Prof Woodgate’s current incidence is less than 3%). These clots can be life-threatening if they break free and travel to your lungs (pulmonary embolism). A prevention program, which may include periodic elevation of your legs, lower leg exercises to increase circulation, short below-knee compression (TED) stockings, calf compressors, early mobilisation, and medication to thin your blood (Clexane injections) is important.  You will also have a Duplex (ultrasound) scan of the lower leg veins 3-5 days post-surgery to look for any signs of DVT formation.

• Dislocation - This occurs when the ball comes out of the socket, with the risk for dislocation being highest in the first few months after surgery while the tissues are healing. Dislocation is uncommon, with a typical reported rate of less than 1%. If the ball does come out of the socket, a closed reduction (under anaesthetic) usually can put it back into place without the need for more surgery. In situations in which the hip continues to dislocate, further surgery may be necessary.

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• Leg length inequality - Sometimes after a hip replacement, one leg may feel longer or shorter than the other, and often this is due to swelling from the surgical procedure.  The leg length inequality may have even been present prior to surgery due to severe bone erosion from the arthritic process. A/Prof Woodgate will use a special measuring device (leg length device) during your total hip surgery to accurately measure lengths prior to and after the replacement so that any corrections can be very accurately made.  This device also allows for an accurate estimate of the offset of the hip (distance between the centre of hip rotation and the long axis of the femur to ensure reconstitution of the gluteal muscle action on the hip. Occasionally, despite accurate intra-operative measurements, there may be a small residual difference, most commonly due to pelvic tilt (obliquity), lumbar spinal curvature (scoliosis), or muscle dysfunction around the hip (abductor/gluteal tendon weakness).

• Fracture of the femur or pelvis – This can occur intra-operatively and require supplemental screw or cable fixation, or later following trauma (such as a fall).

• Loosening and implant wear - Over years, the hip prosthesis may wear out or loosen, and this is most often due to everyday activity. It can also result from a biologic thinning or erosion of the bone called osteolysis. Debonding at the fixation of the cement to bone, or failure of bone ingrowth (if an uncemented implant was used) can also occur. If loosening is painful, or if significant component wear is detected during regular follow-up review, a second surgery called a revision may be necessary. Deep infection may need to be excluded as a cause of loosening.

• Nerve and blood vessel damage – This is rare, though most patients may report a persistent small area of numbness around the surgical wound. Damage to the major (sciatic or femoral) nerves is very uncommon (though it has been reported with different surgical techniques, and A/Prof Woodgate will discuss this with you when planning surgery.
• Blood transfusion for bleeding – With modern anaesthetic and surgical techniques, blood transfusion is uncommon (less than 1%) in primary (first time) total hip replacement.

• Continued pain. A small number of patients continue to have pain after a total hip replacement. This complication is rare and sometimes a clear cause cannot be found. The vast majority of patients experience excellent pain relief following hip replacement.

• Stiffness – Occasionally, patients will fail to regain the expected motion after total hip replacement surgery.  This is often related to long-standing pre-existing hip stiffness that cannot be fully corrected by hip replacement surgery combined with appropriate soft tissue (capsule and tendon) releases.  In the most severe version, patients can occasionally form bone in the capsule and muscles around the hip, a situation known as heterotopic ossification (HTO).  There are certain patients who are known to be at higher risk for post-operative stiffness and HTO, and there are a number of measures that A/Prof Woodgate will discuss with those patients to limit or prevent this unfortunate complication.  The current preferred technique to limit HTO is to undertake a single dose of pre-operative radiotherapy (7-8 Gray) done on the day of surgery prior to the procedure.  It does require a planning visit to the radiotherapist, but in studies over 30 years, it has been shown to be very successful with virtually no complication related to the radiation.  In particular, there has NEVER been a reported case of radiation-induced cancer around a hip replacement following this protocol.

• Pressure sores – This uncommon problem is related to local pressure causing skin breakdown, more commonly noted to develop over bony areas such as the heels or buttocks.  If you notice any pressure or pain developing in these areas, in particular after surgery, it is important to notify A/Prof Woodgate as well as the nurse caring for you in the in the ward. Prevention is much better than cure (if these develop, it can often take months to settle).

Surgical Approach (Mini)Posterior/Anterior/Other?

The posterior/posterolateral approach has been the most commonly used technique for exposure of the hip during replacement surgery throughout the world for many years. A particular advantage of this approach is the easy ability to extend the incision and approach should there be difficult anatomical issues or intra-operative problems encountered. Mini-posterior approach is variably described as having a wound incision less than 10-15cm.

Over the last 5-10 years, there has been increased interest in an older surgical approach called the “Smith-Petersen” approach, which has since been renamed as the “Direct Anterior Approach (DAA), the “intermuscular approach”, or the “internervous approach”.  Advocates of the DAA report that it allows for faster patient recovery as there are “no muscles cut”. The evidence surrounding the DAA being a superior approach to the mini-posterior approach is at best anecdotal and sparse. It has been heavily influenced by conflicts of interest that have been marketed and presented commercially, to both surgeons and general practitioners, by a number of Orthopaedic Implant Companies as a “superior operation performed only by expert surgeons”. Interestingly, there has been a noted increased occurrence of some nerve injuries with patients who have undergone the DAA, both to the lateral cutaneous nerve of the thigh (a sensory nerve) as well as the femoral nerve (a major nerve giving motor supply to the quads muscle group and also having a sensory component).

More recently, an excellent comparative study was undertaken by Dr Mark Pagnano of the Mayo Clinic in Rochester, Minnesota ("Direct Anterior versus Mini posterior THA with the same Advanced Perioperative Protocols: Surprising Early Clinical Results". Pagnano et al. CORR (2015) 473: 623-631).  This study showed NO significant difference in recovery or outcome between either approach in experienced hands, that is, there was no difference at 2 hours, 2 days, or 2 weeks or 2 months between the patients EXCEPT the DAA was more time consuming (longer surgery and anaesthetic time), often required a traction table and intra-operative X-ray control, was more expensive, and was overall technically more demanding (particularly in obese patients).  In fact, the only immediate advantage appears to be that “routine hip precautions” are not required in the post-operative period.

There has been no difference in dislocation rates reported, which is often put forward as a reason for using the DAA, and most series note well below 0.5% incidence. There is a recognised “learning curve” for the DAA technique of about 40 cases, with higher risks of complications and failures during this period. There is an agreed consensus among non-conflicted surgeons that “high volume surgeons generally have less complications and excellent results irrespective of the approach used”, which may be paraphrased as “If it ain’t broke, don’t fix it”.

The Arthroplasty Society of Australia (the subspecialty group of the Australian Orthopaedic Association involved with joint replacement), the American Association of Orthopaedic Surgeons (AAOS), and the American Association of Hip and Knee Surgeons (AAHKS) (A/Prof Woodgate is a member of ALL these associations), all view it is the volume of surgery that is the most important factor in outcomes after total hip replacement, and not the surgical approach utilised. 

A third commonly used approach is the direct lateral approach (also called the transgluteal approach or the Hardinge approach), popularised by Hardinge in 1982. A potential issue with this approach is the possibility of weakness of the abductor (gluteal) muscles if the repair is inadequate or if damage occurs to the b\nerve supply to these muscles with “over-vigorous” exposure or retraction.

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Ultimately, there are pros and cons of each approach and little science to endorse one over the other. Most surgeons tend to have a preference and comfort level with one particular approach over the others. The bottom line is that the best approach is the one your Surgeon is most comfortable with to allow safe and precise implantation of your hip replacement components, and an approach that can be easily extended in the advent of an intra-operative complication.

Preparing for Hip Replacement Surgery

Hip replacement is a common and relatively safe procedure.  Proper preparation and planning can expedite recovery following surgery and improve the likelihood of a successful outcome. There are many ways to prepare for hip replacement surgery, including:

Information

Try to obtain as much information as possible about hip replacement surgery, including the different types of replacements available, the surgical approach, details of expected recovery, and outcomes. This can be done by accessing reputable web sites, such as the Australian Orthopaedic Association ( www.aoa.org.au), the American Academy of Orthopaedic Surgeons ( www.aaos.org), or the American Association of Hip and Knee Surgeons ( www.aahks.org), as well as  www.hipkneetumoursurgery.com

Consultation Questions

You will have many questions for A/Prof Woodgate during your consultation(s) prior to surgery.  Much of the information will have already been discussed but there may be some other points are areas that you wish to have clarified.  Please consider bringing a list of questions, either written on a pad or entered into the note section on your phone, so you are well prepared and that nothing will be missed or forgotten.

Impact on Work

If you are still actively working, you may need to consider the impact that the surgery and the subsequent recovery phase may have on your work and home situation.  Most patients will need at least 3-4 weeks away from work (some require longer periods depending on the demands of your employment.

Prehab

It is possible to speed up your recovery from surgery by improving your general physical condition. Trying to lose a few kilograms is beneficial if you are overweight. Upper body strength will make it easier for mobilizing on a walker or crutches “Prehab” is a pre-surgery rehabilitation programme that can involve physiotherapy, gym and pool work, and many patients have found this to be useful.  Meeting the physiotherapist early also allows instruction of some of the exercises that will be used in the recovery phase. It is also a good opportunity to learn and practice how to use crutches safely.

Pre-op and Post-op Guidelines for Hip Surgery

It is difficult to recover from hip replacement surgery alone. It is important to be fully prepared for your surgical procedure, including having your home made easier to navigate during the recovery phase.  This is outlined in the section “PREOP AND POSTOP GUIDELINES FOR HIP SURGERY”. Work out a plan with family or friends, and if there is no home support system available, it is possible to arrange an inpatient stay at a rehabilitation facility during the post-surgical recovery phase – this also provides an opportunity for early intense physiotherapy and hydrotherapy.  An extended care programme can also be co-ordinated for those wishing to go directly home.

Medical and Anaesthetic Evaluation

If you are proceeding with hip replacement surgery, you may need review by a physician for a complete medical assessment and to optimize your fitness for the operation. This is likely if you have a significant history of cardiac, respiratory or kidney disease, a strong history of DVT, or are on anticoagulants or other blood thinners. You may also need an early anaesthetic review. Further more complex investigative workup may be then ordered.  This will help ensure that the risks of surgery are minimised.

Preadmission Clinic

You may require a formal preadmission clinic visit a week prior to your scheduled operation. As part of this visit, routine blood tests, urine analysis, ECG and X-rays including a chest X-ray will be performed.  Not all patients need a formal assessment – many of these tests can be arranged in the outpatient setting.

Dental Evaluation

Although the incidence of infection after total hip replacement is very low, an infection can occur if bacteria enter the bloodstream. Any major dental procedures (including tooth extractions and periodontal work) should be completed before undertaking your hip replacement surgery. Further, there should be no active gum or mouth infection present. Following hip replacement surgery, A/Prof Woodgate has an ongoing protocol to cover any dental procedures.  If you plan any dental work, at any time after your hip surgery, please contact A/Prof Woodgate for advice.

Medications

You should previously have provided A/Prof Woodgate with a list of all medications you are currently taking, and he will have informed you of which medications should be ceased and at what time. A/Prof Woodgate will also advise alternatives for the blood thinning medications (should this be necessary). You should bring all your medications with you when you are admitted to hospital.

Urinary Evaluations

Patients with a history of recent or frequent urinary infections should have a urological evaluation before surgery, including a urine analysis. Older men who may have prostate disease should consider completing required treatment before undertaking hip replacement surgery.

Skin and Leg Preparation

There should be no skin infections or irritation on your leg, and ideally no significant lower leg chronic swelling. You will be advised to use a skin antiseptic solution (Chlorhexidine body wash) when showering the night before the operation, and on the day of surgery to clean your leg and sterilize the skin (this decreases the number of bacterial organisms that normally live on the skin and could contribute to potential infection).  Do NOT shave your leg prior to the surgery – this will be done in the operating room if necessary.

Admission to Hospital

The Admissions Office at the Hospital will contact you on the day prior to surgery to notify you of the admission time.  You will also be told when to stop eating and drinking prior to the procedure (this is usually 6 hours for solid foods including milk and juice, and 2 hours for sips of water).

Surgical Procedure (Total Hip Replacement)

Total hip replacement is considered to be a major operation, which involves admission to hospital, anaesthesia, rehabilitation and well-defined risks. 

The anaesthesia most commonly used is a spinal block with either sedation or general anaesthesia, and combined with a “Painbuster” catheter that will deliver local anaesthetic directly into the joint (for about 48 hours post surgery). The anaesthetist will ensure you have no awareness during the procedure, and you can be completely asleep if desired. An indwelling urinary catheter will be inserted into your bladder.

The operation will be performed in a designated orthopaedic operating theatre, with strict aseptic conditions, including the surgical team utilising full exhaust “space suits”. Intravenous antibiotic prophylaxis will be given prior to the start of the surgery. The operation site will be swabbed with an antiseptic solution and sterile drapes (cloths) will be placed so that the only thing showing will be the leg to be operated on. The hip will be exposed via the preferred approach.  Just prior to hip dislocation, a separate small “stab” incision will be made at the prominence of the crest of the pelvis to permit insertion of a reference marker pin that will be needed to assess leg length and offset. After carefully identifying and neurovascular structures to preserve them the arthritic hip is dislocated surgically. Standard preparation will then be undertaken with a series of mechanical drills, reamers, and a saw, including removal of the arthritic femoral head (ball). These machining tools accurately prepare the bone surfaces for subsequent implantation of the definitive new hip artificial components. Following relocation of the new hip, the leg length can again be checked to confirm that the planned correction has been achieved, and also an assessment is made to ensure full stable range of motion. Any excessive bleeding is controlled, and the wound is thoroughly irrigated with sterile solution. A drain is inserted to remove excess blood that may collect in the surgical site, and a Painbuster local anaesthetic catheter is also positioned.  The wound is subsequently closed in layers w, including a dissolving suture in the skin, though this may be supplemented with some interrupted Nylon sutures (A/Prof Woodgate does NOT use wound staples as they are associated with a higher risk of deep infection in joint replacement surgery).  Sterile dressings will then be applied to seal the wound. The anaesthetic is then reversed and you will be transferred to the recovery unit. Total hip replacement typically takes 75-120 minutes of surgical time, depending on the complexity of the individual case.

For primary total hip replacement, A/Prof currently uses predominantly the Global Cup, and either the Apex modular stem or the S-ROM modular stem (depending on each individual case situation).

Unlike normal sleep, you will have no sense of the passage of time during the anaesthetic and operation. As soon as you're asleep, you'll feel like you're being woken up and told that operation went very well. As you're waking up you may feel very tired, disoriented, anxious or nauseous. The important thing to realise is that these feelings can be a normal reaction to anaesthesia and surgery. Try to relax and take your time in coming back to full consciousness. You may be instructed in some deep breathing and coughing exercises. These are designed to help reduce the risk of contracting pneumonia by clearing any secretions that may have settled in your lungs during the operation. The nursing staff will closely monitor your stay in the recovery ward until you have fully regained consciousness, which may take a few hours. You will also have an X-ray of the new hip taken in the recovery ward, which will be shown to A/Prof Woodgate prior to your transfer back to the hospital orthopaedic ward.

Post-operative Programme in Hospital 

You will most likely stay in the hospital for 3-6 days for a first-time operation (“primary”), and longer for a “revision” operation. After surgery, you will feel some pain, but medication will be given to you to make you feel as comfortable as possible, and will include regular Paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids often initially delivered via an intravenous route (PCA or Patient Controlled Analgesia – this allows you to control when the pain-reliving medication is provided). Regular ice with packs should be applied to the hip for 20 minutes every 2 hours. Your hip will have bulky compression dressing applied, which will be taken down on day 2.  There will be a drain seen coming through the anterior part of the dressing, which will remove excess blood from within the hip joint – this is removed on either the first or second post-operative day, depending on the losses.  A Painbuster device and catheter will deliver local anaesthetic to the hip joint (this is usually removed on the second post-operative day). As soon as your anaesthetic has worn off, foot and ankle movements are encouraged to also increase blood flow in your leg muscles to help prevent leg swelling and blood clots. 

You will begin a mobilisation programme on day 1, and you will be encouraged to stand and walk fully weight bearing. Mobilisation will commence with a frame, and progress to crutches or a stick. To avoid lung congestion and collapse (known as atelectasis) after surgery, you should breathe deeply and cough frequently to clear your lungs. A simple breathing apparatus called a spirometer (or triflow) may be provided to encourage you to take deep breaths. To minimize the risk of clots (DVT) forming, you will be mobilized early on day 1, short TED (antiembolic) compression stockings applied, as well as inflatable calf compressors, and a blood thinning agent such as Clexane injections will be used. Diet will be reintroduced provided there is no significant nausea. You will have a triangular (abduction) pillow between your legs to stop the legs crossing- this will be used for 6 weeks post surgery.

After 48-72 hours, the PCA machine, drip (intravenous cannula), and bladder catheter are removed, and a regular oral pain programme is started.  Many of these painkilling drugs (especially the opioids) are constipating, and you will need a bowel care programme incorporating regular aperients/ stool softeners to avoid this distressing complication. 

The physiotherapist will assist you with specific exercises to strengthen your leg and carefully restore hip movement. Bending at the hip should not go beyond 90 degrees.

On day 5 (planned discharge day), you will have a Doppler ultrasound scan of the operated leg performed, looking for clots (DVT). The wound dressing will be changed and any advice for planned suture removal will be discussed. You will usually progress onto crutches or a cane fully weight bearing for discharge, though walking aids (crutches or a cane) are often needed for at least 6 weeks. 

Even if you are to be transferred to an inpatient rehabilitation facility rather than going directly home, clear instructions will be given by A/Prof Woodgate with regard to wound care, use of stockings (for 6 weeks), duration of the Clexane (blood thinning) injections (usually for a total 4 weeks), ongoing use of the triangular abduction pillow (for 6 weeks), use of ice, suitability and timing of hydrotherapy, importance of your own self-directed exercise programme when not attending formal physiotherapy, and a pain management programme. Many patients fall into the error of trying to stop painkillers before the hip has settled, so it is important to gradually wean the strong medication only once significant progress has been made.

The Road Transit Authority has a guideline that you should not drive for 6 weeks.

Recovery at Home / Return to Activities and Sports

The long-term success of your hip replacement surgery will depend on how well you continue to look after it.  This will include following A/Prof Woodgate’s instructions and guidelines/precautions to prevent putting the hip at unnecessary risk for failure.  

At the 6 week post-surgery review, A/Prof Woodgate will personally teach you how to avoid problems with “at-risk” manoeuvres, such as how to get in and out of lower seating, how to dry your feet or cut/paint your toenails, how to put on shoes and socks the safe way, how to pick up items from the ground, and how to get items out of low cupboards and drawers. All patients will at some time accidentally fall, and this will undoubtedly cause a significant amount of stress at the time. A/Prof Woodgate will teach you how to get up from the ground, as well as how to safely get down on the ground (useful when going to the beach or to a picnic).

Wound Care

You will have a dissolving suture running beneath your skin on your hip, which may be reinforced with some interrupted nylon skin sutures. The interrupted nylon stitches, when present, will be removed several weeks after surgery. The suture beneath your skin will not require removal.  A waterproof dressing will cover the wound for the first 2 weeks, and after this the wound may be left uncovered if it is healing well, but MUST be recovered with a new waterproof dressing when undertaking hydrotherapy in the first 6 weeks. Avoid soaking the wound in water until it has thoroughly sealed and dried, which may take 4-6 weeks. 

Diet

Some loss of appetite is common for several weeks after surgery, and a balanced diet is important to help your wound heal and to restore muscle strength.

Activity

Exercise is a critical component of the ongoing home care recovery phase, particularly during the first few weeks after surgery. You should be able to resume most normal activities of daily living within 3 to 6 weeks following surgery. Some pain with activity and at night is common for several weeks after surgery. Your activity program should include:

• A graduated walking program to slowly increase your mobility, initially in your home and later outside when you feel safe

• Resuming other normal household activities, such as sitting, standing, and climbing stairs (climbing and descending stairs will initially be done one step at a time, gradually returning to a more normal foot-over-foot technique.  
• Specific exercises several times a day to restore movement and strengthen your hip, which you may be able to perform without help, but you may have a physiotherapist visiting you at home or at a therapy centre can provide assistance, encouragement and guidance during the first few weeks after surgery.

After about 3 months, you can undertake virtually all activities within reason, though of course common sense should always prevail, and this includes walking, hiking, trekking, swimming, skiing (not jumps or moguls), golf, doubles tennis, cycling, scuba diving, horse riding, etc.  If unsure, please discuss with A/Prof Woodgate.

Any particular activity that has a risk of falling or heavy impact may cause potential harm to your new hip, and you do this at your own risk.

Your new hip replacement will continue to improve, and become more normal feeling, for at least 12 months or longer, as the body heals after the surgical procedure.