Total Hip Replacement (THR)

Arthritis of the hips is a very debilitating disease, because it is a weight-bearing joint with a wide arc of range of motion. Arthritis of the hips affect walking, stair climbing, sitting and is also characterised by night pain. That is why a total hip replacement has been judged to be one of the major medical advances of the 20th century. There have been many developments in prosthesis design as well as surgical technique techniques in the past 50 years, since Sir John Charnley managed to achieve good results with accurate surgical technique, prevention of infection, with cemented prosthesis and low friction metal- on- plastic articulation. Many 1st world countries have helped to advance the technology by recording every single replacement surgery in their countries on registers.

Indications for total hip replacements

Pain is the main indication for a total hip replacement in 90% of cases. It is usually advised for hip arthritis, which is causing severe pain and lack of functionality. Arthritis of the hips is a very debilitating disease because it is a weight-bearing joint with a wide arc of range of motion. Arthritis of the hips affect walking, stair climbing, sitting and is also characterised by night pain. The only other indication is to repair functional stability in cases where the joint or surrounding bone has been destroyed due to a hip fracture or severe trauma to the hip and pelvis.

The decision to do a total hip replacement is only considered once all non-surgical options such as analgesics, anti-inflammatory medications and adjustment of activities of daily living have been tried. Only severe hip pain that affects all activities of daily living, (especially sleeping and walking) warrants a total hip replacement. You, as the patient, will be able to decide if the pain is severe enough for a total hip replacement. If you are in doubt, it may be better to take the time to think about it. Delaying the decision will not lead to complications.

The aim of a total hip replacement

Through advances in medicine and the management of chronic diseases in the 21st century, life expectancy is increasing rapidly. These days people playing sports, even competitively, at a much older age has become the norm. For this reason, Dr Morkel is aware that many of his patients expect more from their total hip replacement and have these joint replacement surgeries at a younger age.

Not only are patients expecting greater longevity from hip arthroplasty, but also demanding more stability whilst putting more strain on the prosthesis. The newer designs for hip arthroplasty have resulted in increased longevity and with less host bone resorption compared to the earlier designs. Modern day hip replacements are safe and robust prostheses that will allow younger patients more functional abilities and last longer so that the patient can carry on with their sport and hobbies at the same level.

Because the aim of a total hip replacement is that it will last more than 20 years with excellent functioning for that period, it is important that the orthopaedic surgeon prioritise the alignment and soft tissue tension

Surgical approaches for hip replacements

Total hip replacements are the oldest of joint replacement surgeries, and the results are better than with the other joints due to it being a ball and socket joint. Unlike the other joints which are limited to one approach, there are 3 major surgical approaches to the hip joint when performing total hip replacement surgery. All 3 of these surgical approaches have their pros and cons.

Posterior approach:

The posterior approach is one of the traditional surgical approaches to the hip replacement. It is done while the patient lies on his or her side. An incision is made along the outside of the hip, and the hip joint is accessed from behind the thighbone. Almost any implant can be inserted with this approach. It provides excellent exposure and allows for complex revision surgery. With posterior approach surgery, there is a higher incidence of dislocations but only when performed by inexperienced orthopaedic surgeons.

Anterior lateral approach:

With the anterior lateral approach, one of the traditional approaches, excellent exposure of the hip joint is achieved with the patient on positioned on his or her side and the incision made directly down the outside of the hip. This approach has less risk of post-op dislocations and is also an excellent approach for revision surgery due to the good exposure of the joint. The disadvantage is that a small percentage of patients can have temporary abductor muscle weakness. With modifications to the approach, this very seldom occurs.

Anterior approach:

The direct anterior approaches to hip replacement surgery were developed in France, and it is gaining popularity in the rest of the world. It is reported to allow for smaller skin incisions. Although this exposure is good in an experienced orthopaedic surgeon's hands, it doesn't provide enough exposure for revision surgery. With this approach, access to the femoral canal can be difficult

Which of the three approaches is used will depend on your specific case. Dr Morkel will be able to discuss which approach would be best and the reasoning behind his choice. It has become preferable to do total hip replacements through smaller incisions making it minimally invasive per definition. While Dr Morkel aims to perform surgery through minimally invasive techniques, the most important aspect is that he chooses the most appropriate approach for the hip arthroplasty to provide the best outcome through correct alignment and tension of the prosthesis to improve the longevity of the prosthesis.

Enhanced recovery after Hip Arthroplasty

Soft tissue healing after a total hip replacement depends on the approach used, but is Dr Morkel's aim for better healing. The approach may impact the longevity of the prosthesis, how early the patient is mobile and also plays an important role in prevention of complications. Your recovery after a hip arthroplasty will depend on the approach that was taken by your orthopaedic surgeon.

Dr Morkel will discuss rehabilitation, physical therapy, and any lifestyle changes that might be required post-surgery. The advantage of early mobilisation after arthroplasty is that it means less pain and lower risk of deep vein thrombosis. For early mobilisation that is started the same day as the operation, a multidisciplinary approach which involves the anaesthetist, physiotherapists and all the nursing staff, is needed. Lifestyle changes may have to be made after surgery as you may need to avoid high-impact sports, heavy lifting or climbing. You can expect to be back to your normal activities within 4 weeks of surgery. Full recovery may take up to a year

Complications of Hip Arthroplasty

Recurrent dislocations

The general incidence of dislocations following total hip replacements is: There seems to be a higher incidence of dislocations with hip replacements performed through the posterior approach, but experienced surgeons can achieve the same figures with all the different approaches. With Dr Morkel's attention to detail in the alignment of the prosthesis, tension of soft tissue and post-operative rehabilitation, he is able to assist in preventing hip dislocations of his patients.

Deep vein thrombosis

There is a risk for deep vein thrombosis (DVT) in primary total hip replacements and pulmonary embolism as a complication. Prevention of DVT is important and depends on good hydration, early mobilisation, foot pumps, and chemical trombo-prophylaxis (low molecular heparin, Warfarin and newer anticoagulants).


There is always a risk of infection with major surgeries, and despite advances in prevention and antibiotics, it remains a concern. Prevention is still the best way to cure. For that reason, after a total hip replacement, the patient is investigated for any possible source of infection. Intra-operatively the principles that we adhere to prevent infections is laminar flow operating theatres, prophylactic antibiotics, accurate and precise surgical techniques, prevention of haematomas (collection of blood in operating sites) and special care with barrier nursing. Superficial infections can be treated effectively with antibiotics, but deep chronic infection might need a revision of the prosthesis.

Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a chronic pain condition most often affecting one of the limbs (arms, legs, hands, or feet), usually after an injury, trauma or trauma to that limb. CRPS is believed to be caused by malfunction of the peripheral and central nervous systems. Although rare, it can occur after hip arthroplasty. It is important that it is diagnosed early, and pain modulation treatment is started early for resolution of this potentially debilitating condition.

Heterotopic bone formation

Heterotopic bone formation in the muscle surrounding the hip can occur in 12% of hip replacements. This can lead to temporary stiffness and in severe cases require removal of the extra bone, once it has matured.

Frequently asked questions

What type of Total hip replacement prosthesis is the best?

There are so many different makes of hip prostheses which can be classified into either cemented and uncemented prosthesis with hard on soft and hard on hard articulations. There is also bone conserving metal on metal (resurfacing) prosthesis. Generally, younger patients have better bone quality and will demand longer survival from their prosthesis. There are very specific indications for a different prosthesis in different patients. These days the Swedish, Norwegian, British, American, Australian, New Zealand and recently SA national joint registers provide us with data on any prosthesis. These registers can give important information on different prosthesis longevity, complications and surgeons results. It is for that reason that Dr Morkel support joint registers and all his procedures and prosthesis are documented on the SA National Joint Register.

What type of articulations is the best?

Each of the different articulations has its pros and cons. Modern cross-linking techniques of high-density polyethene HDPE (plastic) and Vit E treatment promises extended survival of plastic acetabular liners/prosthesis. In laboratory studies, ceramic femoral head prostheses seem to promise better longevity than metal (cobalt chrome). There will always be particles released in plastic ceramic or cobalt chrome articulations, but these stay contained in the hip.

Is metal on metal articulations safe?

20 years ago when the resurfacing prosthesis was designed in the UK, it seemed to promise a stable large head articulation and bone preservation that promised to be the solution orthopaedic surgeons and patients were looking for.
In many cases, these resurfacing hip procedures did very well, but when the acetabular prosthesis alignment was not accurate, it led to foreign body reactions and early revision procedures for the patients. The different designs from other companies in resurfacing prosthesis that followed the original designs, could also not deliver the same result. Excellent medium-term results have been achieved by experienced surgeons with the original prosthesis. If a male patient considers a resurfacing prosthesis, it is essential to find an experienced orthopaedic surgeon in the procedure and to have the original design implanted. Females and patients with sensitivity to metal must not consider it as an option. Metal on metal articulations carries a risk of elevated cobalt and chrome ions in the blood and possible long term issues for patients. There is also a very small percentage of patients with allergies to chrome and nickel that develop allergic reactions to these ions in the body.

What is the best replacement for me?

It depends on your age, demands and bone morphology. The best is to choose an orthopaedic surgeon who you trust, who does a reasonable amount of total hip replacements and is available if there are any post-surgery hiccups. Allow Dr Morkel to choose the prosthesis after all the pros and cons have been discussed.

What is the best surgical approach for a total hip replacement?

Each of the different approaches has its pro and cons. The alignment and soft tissue tension determines the long term survival of the prosthesis and is much more important than the promise of returning to sport a few days quicker. It is best that the surgeon is comfortable with the approach that gives him or her the best ability to align the prosthesis and achieve the necessary exposure to implant the prosthesis with the necessary care to detail for the best long term outcome.

Minimally invasive hip surgery - a fad or a must have?

The length of the surgical scar is less important than the alignment and tissue tension in determining long term outcomes. Total hip replacements, although a very successful procedure, still carry risk and often specialised observation in the immediate post-operative period, can prevent complications. While the cosmetic appearance is important, it should not be more important than the patient's health or long term outcomes.

How long after the total hip replacement can I drive a motor vehicle?

This will depend on the approach that Dr Morkel uses, but a general rule is that 4-6 weeks after a total hip replacement should be a safe period to return to driving.

How can I prevent dislocation after a hip replacement?

Soft tissue healing in the immediate few weeks post-surgery is important to ensure the longevity of the hip arthroplasty. The physiotherapist will instruct patients how to navigate and mobilize sufficiently for enhanced recovery safely. Keeping to 4 basic principles: not to cross legs, not bend legs up beyond 90 degrees, not sit on sofas or in low chairs and not to sleep on the side should aid the results.

What about prophylactic antibiotics for surgical procedures or dental procedures post hip replacement?

Total hip replacement implants are large prosthesis, and there can be an increased risk with systemic bacterial infections. Small surgical procedures and localised infections are most probably not an extremely high risk, but taking amoxicillin as prophylactic antibiotic also should not lead to complications. General principles of early detection of systemic infections and balanced lifestyle supporting a vibrant immune system should be enough to ensure the longevity of the prosthesis.

Which sports are safe after hip arthroplasty?

All low impact sports that the patient participated in before the total hip replacement should be safe. Low impact sports include; tennis, golf, cycling, lawn bowls, alpine skiing, hockey, social squash, hiking and body boarding. Contact sports and high impact sports will not be possible. High impact sports include long distance running, rugby and extreme sports like kiteboarding, wakeboarding, surfing and bungee jumping. If someone is skilled at certain sports like alpine skiing or water skiing, for instance, it will be a safe sport to return to, but not to start as a new sport after the joint replacement.

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