Total Hip Replacement

A comprehensive summary of Dr. Solomon's recommendation for hip replacement surgery and the type of surgery performed is shown.

Further information on hip replacements and animations are found after the summary.

Information for patients needing a Total Hip Replacement or Hip Resurfacing Replacement


If you have been diagnosed with an arthritic hip you may benefit from hip surgery.

Timing of Surgery

The timing of hip replacement surgery is a decision that you as the patient must make. The need for surgery is a quality of life decision and the aim of the surgery is to eliminate your hip pain. As an added bonus you will likely get a better range of motion, your limp may reduce or disappear and your quality of life should improve significantly.

If you feel that you can manage with your current pain levels then there is no urgency to have your arthritic hip replaced. Simple analgesics (eg.Panadol) or anti-inflammatories (eg.voltaren, celbrex etc) may be sufficient to provide you with a relatively painfree hip. These drugs will not improve stiffness and the arthritis will continue to progress and at some point the drugs will no longer have their pain relief affect.

Alternative medicines (eg. Glucosamine and chondroitin, fish oil etc) may have a role in helping with pain but scientific studies have proven that the claim that they “prevent arthritis or progression of the disease” is false. These medicines whilst not doing you major harm will not stop your hip continuing to wear out.

If you are overweight, weight loss may help in reducing your hip pain. Low impact exercises (walking, cycling and swimming) help maintain muscle tone and thereby control the arthritis pain.

Physiotherapy is often useful in helping strengthen surrounding muscles and maintaining good muscle tone and pelvic balance. Try to avoid overstretching the joint as this will only cause discomfort.


Things you need to know about Hip Replacements and Hip Resurfacing Replacements

Total Hip Replacement, Hip Resurfacing Replacement or “mini stem” Hip Replacement are simply different designs of prosthesis. They all replace your hip and therefore are collectively termed Hip Replacements. Some prosthesis (Birmingham Hip Resurfacing) are more bone conserving but these prosthesis still replace the acetabulum (socket) and either resurface the femoral head (ball) or replace the head but preserve more bone lower down.


What Replacement should you have ?


This can be a most complex topic particularly in discussing the options and correct choice in a young patient.

It is important to get an understanding of what’s available and in which patient group you are best placed.

The key to a successful hip replacement is the surgical skill of the surgeon implanting the prosthesis and the type of bearing used in the ball and socket joint.

Modern day hip prosthesis may well last a patient a lifetime. It is most likely that a well recognized, tried and tested implant will not wear out in patients over the age of 70 provided the surgery is performed correctly. The key to implant longevity apart from good surgical technique is the materials used in the bearing (the actual parts that move).

Facts about bearings

The traditional hip bearing is a metal head (chrome cobalt ball) that moves on a polyethelene liner (“plastic” liner). Modern day plastic liners have very low wear rates unlike the material used 30 years ago. Studies show that modern day liners will probably take about 30 years to wear out. It is for this reason that it is likely that an artificial hip joint implanted in a patient over the age of 70 will last them a lifetime. Off course should the lining wear out sooner a new plastic lining can be inserted.

In an effort to develop bearings that last longer than the traditional “plastic” lining, a number of other alternatives are available. These include the following

1. Ceramic on Ceramic

2. Metal on Metal

3. Ceramic on Metal

These bearings were developed to allow younger patients to have hip replacements as they may last longer than traditional metal on plastic bearings and hopefully last a “lifetime”

Ceramic on Ceramic

The ceramic – ceramic bearings have been around for over 20 years. They have extremely low wear rates (1000 times less than plastic) and if implanted correctly may last 40 years or more.

Unfortunately ceramics are not perfect in that there is a 1 in 20 000 incidence of breakage / fracture (ceramic is more brittle than metal) and a very rare chance that the hip can develop a squeak.

In general however ceramic on ceramic bearings are an excellent choice to use in the young patient (under the age of 60). Surgical technique is critical.

Metal on Metal Bearings

These bearings have been around for over 30 years but have regained popularity with the introduction of modern designed hip resurfacing replacements.

The wear rate of metal on metal bearings is only slightly higher than ceramic on ceramic but like ceramics is significantly lower than metal on plastic bearings. Metal on metal bearings are very tough and are not susceptible to breakage (fracture).

The disadvantage of metal on metal bearings is that they produce metal ion particles and if the implant is not functioning properly these metal ions can invoke a significant inflammatory response in and around the hip joint which can cause hip pain and swelling.

Some patients are allergic to metal on metal implants but this is extremely rare. Some metal on metal bearings squeak but this is usually a temporary phenomenon.




Hip Resurfacing:

Hip Resurfacing Replacements were designed to preserve bone so that should a patient require a revision in the future there was adequate bone left to revise the hip. This type of replacement is reserved for patients with good quality bone ie: no osteoporosis. It is therefore not suitable for elderly patients as there is a high risk of fracture of the bone that the implant is attached to.

THERE IS NO ADVANTAGE FOR A PATIENT OVER THE AGE OF 65 TO HAVE A HIP RESURFACING

Modern day resurfacings have been around for the past 14 years. The Birmingham Hip Resurfacing Replacement (Smith & Nephew Inc: www.smith-nephew.com) is the most successful of the Resurfacings on the market and has the longest track record (over 14 years) We have learned a great deal about resurfacings and the literature (including the Australian Joint Registry www.dmac.adelaide.edu.au/aoanjrr/) has outlined the best patients that are suited for this procedure.

Resurfacings do best in the young (less than 55 yr old) male or female with a large femoral head and who have primary osteoarthritis (ie primary osteoarthritis is wear and tear not due to underlying issues such as rheumatoid disease, shallow hip disease, avascular necrosis).

Males under age 55 with osteoarthritis that have femoral head sizes 50mm or more do best with a BHR resurfacing implant compared to other hip replacements. This data is shown on the Australian National Joint Registary as of Dec 2010.

Most females however have smaller bones than males and therefore are not ideally suited to resurfacing replacement using available data.

In my practice I recommend hip resurfacing in the young active male with strong bone and a large femoral head.

Important facts to know about hip resurfacing:

Hip resurfacing patients take LONGER to recover than conventional total hip surgery patients. The reason for this is that in order to preserve the femoral head for resurfacing, more muscle and ligaments need to be released internally to allow the socket to be prepared. Patients are also advised to partial weight bear for 4 weeks post operatively to allow the bone to adapt to the new implant and not fracture. Conventional hip replacement patients are allowed to full weight bear immediately.

Hip Range of Motion in Resurfacing replacements is LESS than conventional total hip replacements using the same size ball and socket. The reason for this is that the resurfacing sits on the patient’s femoral head and neck and as such in maximal motion the femoral neck may impinge on bone preventing maximum movement compared to a ball that sits on a stemmed hip because the stemmed hip has a narrow neck allowing more impingement free motion (see drawing)

Activity Level:

A good functioning hip resurfacing is very durable and whilst it is not recommended, there have been many reports of patients running and doing triathlons with resurfacings.

ALL hip replacements, resurfacing or conventional, allow the patient to partake in sporting activities including
Tennis
Skiing
Golf
Bowls
Backyard running with the kids
Cycling
swimming

As a general rule orthopaedic surgeons do not recommend high contact sports with ANY type of replacement (resurfacing or conventional) including rugby, competition soccer, competition basketball etc)

So what’s the advantage in having a resurfacing ??

Resurfacings preserve the femoral shaft and there are reports that some patients feel that the resurfaced hip “feels more natural”

It allows the possibility of a future revision to be done without to much difficulty HOWEVER it is likely that a well done standard total hip replacement with a modern day bearing will not need revising anyhow.

The BIGGEST issue with metal on metal resurfacings is accuracy in surgical technique. This fact has only recently come to our attention as it was thought that metal on metal implants are as “forgiving” as metal on plastic implants. Recent literature has shown that the metal on metal implants (and ceramic on ceramic bearings) are very susceptible to mal-alignment and if this occurs then these implants may fail.


Minimally Invasive Hip Surgery and Anterior Approach 

Is this a marketing ploy or are the results better ??

There has been a lot of recent advertising press about the mini incision hip, anterior approach technique etc etc.

There are many approaches to implant a hip replacement. Over the last decade surgeons have become more skilled in making smaller incisions using refined techniques with better instrumentation.

Some approaches are more muscle sparing than others and recovery may be a little quicker HOWEVER the most important aspect of any hip surgery is to ensure that the prosthesis is implanted accurately and correctly, that the surgery is carried out in an efficient manner minimizing blood loss and reducing anaesthetic time and the risk of complications is kept to a minimum.

ANY approach will produce a good functional pain free outcome provided the surgeon is skilled at what he is doing.

The Anterior Approach (from the front) is more muscle sparing and allows a slightly quicker recovery. Patient selection is important and not all patients are suitable for this approach.  This approach has a higher complication rate related to the technique and it is important that you choose a surgeon who is skilled in this technique.  Whilst patients may recover  quicker there is NO evidence to show that at 6 months post surgery there is any difference in functional outcome. Studies are on-going to evaluate the long term benefit of this approach.

ANTERIOR MINIMALLY INVASIVE APPROACH TO HIP REPLACEMENT.   Further information current as of May 2011


Total Hip Replacement surgery has now been in existence for almost 50 years. There are various surgical approaches that enable the surgeon to enter the hip joint and replace the arthritic hip. 

Most surgical approaches involve splitting or dividing muscles / tendons and then repairing them at the end of the procedure.

The anterior approach to the hip joint was initially developed in 1949 / 1950 by Smith Peterson (USA) and Judet (France). The approach was developed to allow access to the hip joint by not dividing muscles or tendons and allowing exposure of the hip by going between muscles. 

For 40 years the French used a traction table to perform hip replacement surgery however most of the orthopaedic world preferred to perform the surgery with the patient on their side allowing entry into the hip joint either through the side (transgluteal) or the back (posterior) approach. The posterior approach is the most popular approach used by surgeons all over the world as it is a very straight forward approach allowing good visualization of the hip joint.

The literature shows no evidence at 1 year post op that any approach is better than another with excellent clinical outcomes shown in all approaches.

In the last 7 years advances in technology in the design of equipment and instrumentation has allowed the surgeon to implant a hip through the anterior muscle sparing approach using a versatile traction table.

Published results have shown that a patient who undergoes a successful direct anterior approach hip replacement will recover quicker than conventional approaches. At this stage however there is no evidence that there is any long term advantage between approaches although should that patient require revision surgery in the future, there is a theoretical benefit as the anterior approach results in less internal scarring than other approaches.

Not all patients are suitable for the AMIS technique. Patients who are significantly overweight are at risk of having intraoperative complications due to limited visibility. Patients with abnormal hip joint anatomy are not suitable for the AMIS approach as this approach does not allow the correction of severe hip deformities. Some patients with very soft bone may not be suitable for the AMIS approach as there is a risk of fracture. Most revision hip surgery needs to be performed through conventional approaches.

The most important part of hip replacement surgery is that the surgeon implants the replacement safely and in excellent alignment to ensure optimum hip function, full pain relief and long term success of the implant.

Remember that ALL approaches if performed correctly will result in a successful pain free outcome that should last at least 20-30 years using modern day implants.

All patients would prefer a quicker recovery and therefore my approach is to use the AMIS procedure provided there are no contraindications.

Advantages of the AMIS approach include

1. Less muscle damage
2. Surgery between muscle groups supplied by different nerves (internervous)
3. Earlier recovery with quicker return to function
4. Reduced incidence of hip dislocation 
5. Ability to return to activities such as driving earlier
6. Reduced post operative precautions whilst the wound heals compared to other approaches.
7. Smaller scar
8. Post operative rehabilitation is easier and quicker



Cemented or Uncemented prosthesis:

There is NO difference in the revision rates of either a cemented or uncemented femoral component (the hip stem that sits on the thigh bone). A well implanted cemented stem works just as well as a well implanted uncemented stem. As outlined above the key to longevity is in the bearing and NOT whether the stem is cemented or uncemented. A surgeon will choose what stem fits best into your bone quality. In general softer osteoporotic bone with thin cortices do better when cement is used to fixate the implant.

Most acetabular components (sockets) are uncemented and the bone will grow into the component. The lining is then placed in the metal shell and this lining is either plastic, ceramic or metal. Occasionally the bone is so soft that a plastic liner is cemented onto the bone instead of using and uncemented shell..


The Final word

I hope I have enlightened you on the basic facts about hip replacement surgery. I would summarize as follows:

1. Choose a surgeon who is well experienced in Hip Replacement Surgery
2. Be guided by the information presented above as to the types of hip replacements available, bearing options and operative approaches.
3. Do not be fooled by advertising and marketing hype.


My approach and recommendations to patients requiring a hip replacement. This is a GUIDE ONLY and each patient’s individual needs are taken into account before a final implant decision is made

1. Patients over the age of 75 usually have an uncemented stem (if bone quality good) or cemented stem (if bone quality poor) with an uncemented socket and polyethelene (plastic) liner. A metal head is used. This hip should last a lifetime

2. Patients between 65-75 usually have an uncemented stem and socket with either a ceramic on ceramic liner or ceramic on polyethelene liner. This hip should last a lifetime

3. Males under the age of 60 who are active and have excellent bone quality are candidates for a resurfacing HOWEVER we discuss the pros and cons of resurfacing vs  total hip replacement with a ceramic bearing according to the patients individual circumstances.

4. Females under age 65 usually have an uncemented stem and socket with a ceramic on ceramic bearing

5. Males between 55-75 usually have an uncemented stem and socket with the bearing appropriate for their age.

6. Males under 55 have a resurfacing if they satisfy various criteria or an uncemented implant with a ceramic on ceramic bearing.

Michael Solomon
(Revised May 2011)

 

Normal Anatomy :: Total Hip Replacement THR
Hip Resurfacing :: Revision Hip Replacement

Normal Anatomy of the Hip Joint

Total Hip Replacement

• Introduction
• Arthritis
• Indications
• Benefits
• Pre-operation
• Day of Your Surgery
• Surgical Procedure
• Post-operative
• Special Precautions
• Risks and Complications
• Summary

Introduction

Hip replacement has become necessary for your arthritic hip: this is one of the most effective operations known and should give you many years of freedom from pain.

Once you have arthritis which has not responded to conservative treatment, you may well be a candidate for total hip replacement surgery.

Arthritis

Arthritis is a general term covering numerous conditions where the joint surface (cartilage) wears out. The joint surface is covered by a smooth articular surface that allows pain free movement in the joint. This surface can wear out for a number of reasons, often the definite cause is not known. When the articular cartilage wears out, the bone ends rub on one another and cause pain. There are numerous conditions that can cause arthritis and often the exact cause is never known. In general, but not always, it affects people as they get older (Osteoarthritis).

Other causes include

• Childhood disorders e.g., dislocated hip, Perthe's disease, slipped epiphysis etc
• Growth abnormalities of the hip (such as a shallow socket) may lead to premature arthritis
• Trauma (fracture)
• Increased stress e.g., overuse, overweight, etc.
• Avascular necrosis (loss of blood supply)
• Infection
• Connective tissue disorders
• Inactive lifestyle- e.g., Obesity, as additional weight puts extra force through your joints which can lead to arthritis over a period of time
• Inflammation e.g., Rheumatoid arthritis

In an arthritic hip

• The cartilage lining is thinner than normal or completely absent
• The degree of cartilage damage and inflammation varies with the type and stage of arthritis
• The capsule of the arthritic hip is swollen
• The joint space is narrowed and irregular in outline; this can be seen in an X-ray image
• Bone spurs or excessive bone can also build up around the edges of the joint
• The combinations of these factors make the arthritic hip stiff and limit activities due to pain or fatigue

Diagnosis

The diagnosis of osteoarthritis is made on history, physical examination & X-rays. There is no blood test to diagnose Osteoarthritis (wear & tear arthritis)

Indications

THR is indicated for arthritis of the hip that has failed to respond to conservative (non-operative) treatment.

You should consider a THR when you have

• Arthritis confirmed on X-ray
• Pain not responding to analgesics or anti-inflammatories
• Limitations of activities of daily living including your leisure activities, sport or work
• Pain keeping you awake at night
• Stiffness in the hip making mobility difficult

Benefits

Prior to surgery you will usually have tried some simple treatments such as simple analgesics, weight loss, anti-inflammatory medications, modification of your activities, walking sticks, physiotherapy.

The decision to proceed with THR surgery is a cooperative one between you, your surgeon, family and your local doctor. Benefits of surgery include

• Reduced hip pain
• Increased mobility and movement
• Correction of deformity
• Equalization of leg length (not guaranteed)
• Increased leg strength
• Improved quality of life, ability to return to normal activities
• Enables you to sleep without pain

Pre-operation

• Your surgeon will send you for routine blood tests and any other investigations required prior to your surgery
• You may be asked to undertake a general medical check-up with a physician
• You should have any other medical, surgical or dental problems attended to prior to your surgery
• Make arrangements around the house prior to surgery
• Cease aspirin or anti-inflammatory medications 10 days prior to surgery as they can cause bleeding
• Cease any naturopathic or herbal medications 10 days before surgery
• Stop smoking as long as possible prior to surgery

Day of Your Surgery

• You will be admitted to hospital usually on the day of your surgery
• Further tests may be required on admission
• You will meet the nurses and answer some questions for the hospital records
• You will meet your anaesthetist, who will ask you a few questions
• You will be given hospital clothes to change into and have a shower prior to surgery
• The operation site will be shaved and cleaned
• Approximately 30 mins prior to surgery, you will be transferred to the operating theatre

Surgical Procedure

An incision is made over the hip to expose the hip joint

The acetabulum (socket) is prepared using a special instrument called a reamer. The acetabular component is then inserted into the socket. This is sometimes reinforced with screws or occasionally cemented. A liner which can be made of plastic, metal or ceramic material is then placed inside the acetabular component.

The femur (thigh bone) is then prepared. The femoral head which is arthritic is cut off and the bone prepared using special instruments, to exactly fit the new metal femoral component. The femoral component is then inserted into the femur. This may be press fit relying on bone to grow into it or cemented depending on a number of factors such as bone quality and surgeon's preference.

The real femoral head component is then placed on the femoral stem. This can be made of metal or ceramic.

The hip is then reduced again, for the last time.

The muscles and soft tissues are then closed carefully.

Post-operative

You will wake up in the recovery room with a number of monitors to record your vitals. (Blood pressure, Pulse, Oxygen saturation, temperature, etc.) You will have a dressing on your hip and drains coming out of your wound.

Post-operative X-rays will be performed in recovery.

Once you are stable and awake you will be taken back to the ward.

You will have one or two drips in your arm for fluid and pain relief. This will be explained to you by your anaesthetist.

On the day following surgery, your drains will usually be removed and you will be allowed to sit out of bed or walk depending on your surgeons preference. .

You will be able to put all your weight on your hip and your Physiotherapist will help you with the post-op hip exercises.

You will be discharged to go home or a rehabilitation hospital approximately 4-6 days depending on your pain and help at home.

Sutures are usually dissolvable but if not are removed at about 10 days.

A post-operative visit will be arranged prior to your discharge.

Post-op precautions

Remember this is an artificial hip and must be treated with care.

AVOID THE COMBINED MOVEMENT OF BENDING YOUR HIP AND TURNING YOUR FOOT IN. This can cause DISLOCATION. 

You will be advised on various precautions that you need to take for 1 month after surgery
 

• You should sleep with a pillow between your legs for 4 weeks. Avoid crossing your legs and bending your hip past a right angle
• Avoid low chairs
• Avoid bending over to pick things up. Grabbers are helpful as are shoe horns or slip on shoes
• Elevated toilet seat helpful
• You can shower as the dressing is waterproof
• You can apply Vitamin E or moisturizing cream into the wound once the wound has healed
• If you have increasing redness or swelling in the wound or temperatures over 37.5 you should call your doctor
• If you are having any procedures such as dental work or any other surgery you should take antibiotics on the day of the procedure to prevent infection in your new prosthesis. Consult your surgeon for details
• Your hip replacement may go off in a metal detector at the airport

Risks and Complications

As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages.

It is important that you are informed of these risks before the surgery takes place.

Complications can be medical (general) or specific to the hip

Medical Complications include those of the anesthetic and your general well being. Almost any medical condition can occur so this list is not complete.

Complications include

• Allergic reactions to medications
• Blood loss requiring transfusion with its low risk of disease transmission
• Heart attacks, strokes, kidney failure, pneumonia, bladder infections
• Complications from nerve blocks such as infection or nerve damage
• Serious medical problems can lead to ongoing health concerns, prolonged hospitalization or rarely death

Specific complications include

Infection

Infection can occur with any operation. In the hip this can be superficial or deep. Infection rates are approximately 1%, if it occurs it can be treated with antibiotics but may require further surgery. Very rarely your hip may need to be removed to eradicate infection.

Dislocation.

This means the hip comes out of its socket. Precautions need to be taken with your new hip forever. It a dislocation occurs it needs to be put back into place with an anaesthetic. Rarely this becomes a recurrent problem needing further surgery.

Blood clots (Deep Venous Thrombosis)

These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify your surgeon.

Damage to nerves or blood vessels

Also rare but can lead to weakness and loss of sensation in part of the leg. Damage to blood vessels may require further surgery if bleeding is ongoing.

Wound irritation

Your scar can be sensitive or have a surrounding area of numbness. This normally decreases over time and does not lead to any problems with your new joint.

Leg length inequality

It may be difficult to make the leg exactly the same length as the other one. measure are taken intra-operatively to achieve equal leg lengths. Occasionally the leg is deliberately lengthened to make the hip stable during surgery. There are some occasions when it is simply not possible to match the leg lengths. All leg length inequalities can be treated by a simple shoe raise on the shorter side.

Wear

All joints eventually wear out. The more active you are, the quicker this will occur. In general 80-90% of hip replacements will survive 15-20 years.

Failure to relieve pain

Very rare but may occur especially if some pain is coming from other areas such as the spine.

Unsightly or thickened scar

Limp due to muscle weakness

Fractures (break) of the femur (thigh bone) or pelvis (hipbone)

This is also rare but can occur during or after surgery. This may prolong your recovery, or require further surgery. Discuss your concerns thoroughly with your orthopaedic surgeon prior to surgery.

Summary

Surgery is not a pleasant prospect for anyone, but for some people with arthritis, it could mean the difference between leading a normal life or putting up with a debilitating condition. Surgery can be regarded as part of your treatment plan- it may help to restore function to your damaged joints as well as relieve pain.