Osteoarthritis is a common disabling condition that causes general joint pain and stiffness caused by gradual erosion of cartilage. Hip osteoarthritis causes restricted physical activity and functional disability from pain around the hip, buttocks and even the thigh. This loss of function may convince patients that their worn out hip joint requires a replacement. A total hip replacement (THR) procedure is the standard of care for end stage hip arthritis. It involves removal of worn out parts of the hip joint and it's replacement with implants. This is just like how tyres are replaced in a car. While osteoarthritis may be the most common form of arthritis, other causes of arthritis include inflammatory arthritis (Rheumatoid arthritis, ankylosing spondylitis), avascular necrosis, post traumatic arthritis (after a hip fracture) or dysplasia (shallow hips).
A: both hips are worn out in this patient with underlying hip dysplasia. Notice how the right hip has migrated upwards leaving to some differences in the patient’s leg lengths.
B: both hips have been replaced with implants at the same time. This is to allow meaningful and effective physiotherapy and rehabilitation to occur.
C D E
C: image of a worn out hip, D: the different components of a total hip replacement implant. E: What a hip looks like after it has been replaced.
Initial Recovery: Typical recovery timeline and milestones
Pain Relief: Reduction in chronic pain levels
Mobility Improvement: Early improvements in walking and joint function
Most patients are admitted between one night and three nights in hospital after a total hip replacement. This certainly depends on many critical factors such as patients’ physical condition, pain levels, the ability to walk with or without walking aids to name a few. Most surgeons will continue prophylactic or preventative antibiotics for about 24 hours and allow patients to go home with oral painkillers. The pre-operative hip pain that patients had been suffering from for years should be completely gone. Patients will however feel some pain where their soft tissues and muscles are bruised from the surgery itself. The earlier patients walk, the less chance for muscles to weaken. If the surgery was performed through the posterior approach, there will be some hip restrictions imposed such as to avoid squatting, crossing your legs and kneeling. There are no such precautions if patients have their surgery through the anterior approach. I always remind patients that whatever pain and discomfort they may feel on day 1, it will continue to improve daily. Physiotherapists help patients achieve these goals as soon as they are able to get on their feet.
Patients are followed up weekly or two weekly till their wounds heal up and they are walking without much problems. Most patients do not require any walking aids after a week or two. They’re allowed to drive after about 3 weeks when they no longer require any strong pain medication. I encourage my patients to participate in low impact sports such as brisk walking and cycling within a month. Most will participate in physiotherapy as part of their rehab for about 6 weeks before they do their own stretching and exercise.
Joint Functionality: Increased range of motion and strength
Activity Level: Ability to return to normal activities and low-impact sports
Complication Rates: Common complications and their management (e.g., infection, dislocation)
Every patient is different in terms of their age, physical strength, level of activity, motivation and weight. Each will therefore experience a slightly different rehab journey. As most patients are already above 50 years old when they have their hip replacement, most will not require any second hip surgery or revision surgery in their lifetime. In general, physical activities do tail off after 70 or 75 years old hence the stress on the implants will be even less.
Physiotherapy is a critical part of rehab and regaining function after surgery. It comes in several stages focusing on range of motion, strengthening, balance and finally, performance. There is a constant conversation between patients and physiotherapist in terms of their rehab targets and timelines. This is unique for each patient. From an orthopaedic surgeon point of view, we encourage early and regular non-impact sports to allow patients to maintain their muscle strength, physical function and do the things they were not able to do while experience hip pain. We are just more cautious in the first few weeks while the wound has not fully healed yet. The risk of hip dislocation is extremely rare in operations done through the anterior approach so we don’t restrict patients’ activities. We love to hear that our patients have gone for an overseas holiday and taken up new hobbies or are actively taking care of their grandchildren.
Prosthetic Longevity: Expected lifespan of hip implants
Revisions and Reoperations: Frequency and reasons for revision surgeries
Quality of Life: Sustained improvements in daily activities and pain levels
Life expectancy is rising and so the survivorship of the total hi preplacement implant is very relevant.
The longevity of hip implants is multi-factorial. The lifetime risk of revision changes according to the age of the patient at the time hip replacement was implanted, with older patients having a lower lifetime risk of revision. Younger patients who are obese and participate in high impact sports are more likely to require a revision in their lifetimes. Reasons why implants fail include loosening, infection, fractures around the implant, persistent pain, dislocation and wear. Around the world, countries keep a registry of all the hip implants used for patients as well as record of which hips require revision surgeries. The data collection in various countries differ significantly and so that numbers have to be taken in context. Some of the implants used in these historical records are no longer used and the new implants do now have such a long follow up period. In general, most implants will last about 25 to 30 years without requiring a revision surgery based on publish data (The Lancet, How long does a hip replacement last? A systemic review. 2019). Several overall survival estimates have also been studied between patients younger and older than 55 years old at the time of surgery. The 15 year survival was about 86% in Denmark, 88% in Sweden, 87% in Norway and 84% in Finland.
All said and done, when patients have hip pain from arthritis and their quality of life is severely compromised, we will still proceed with the total hip replacement sooner rather than later once all other conservative measures have failed. Patients appreciate their quality of life and living an active one now and not when they are in their 70s or 80s when life has mostly gone by. They may or may not need a revision operation in future and most are happy to address this issue when they get to that bridge in future.
Patient Factors: Age, activity level, overall health
Surgical Factors: Choice of prosthetic, surgical technique (e.g. DAA)
Post-Surgical Care: Adherence to rehabilitation protocols, lifestyle choices
I often compare replacing a hip to replacing a tyre of a car. The car must firstly have a good engine, gears and suspension to work well and safely. Without these basic parts, there is no point in replacing its tyres.
Similarly, patients must have basic health and physical function with a good rehab potential for surgeons to decide that the hip replacement surgery will do the patient more good than harm. If patients have been bedridden for several months or years, if they have poorly controlled diabetes or a severely weak heart, they may not be a candidate for a total hip replacement at that point of time. I often send them for physiotherapy to build up their muscles and strength before surgery. They may also have to see various other specialists such as a cardiologist or diabetic specialist to optimise their health. In the meantime, I may give them oral painkillers or a steroid injection into their hip to reduce their pain.
While there is a lot of discussion about the choice of bearings of the hip (metal head versus ceramic head), it is just as important to discuss the material of the cup liner. There are ceramic and plastic liners. Ceramic heads and ceramic cup liners are associated with good longevity but may be associated with squeaking during certain movements. These ceramic liners only come in neutral alignment and do not have other configurations that help surgeons achieve a stable hip. The plastic liner comes in neutral, greater thickness or offset as well as a lip in the front to help achieve greater hip stability. This is especially important in posterior surgeons to reduce their risk of hip dislocation.
Different types of plastic cup liners to help surgeons customise their implant choice and achieve greater hip stability. Ceramic liners do not have such variety.
Despite all this talk about implants and their materials, it still comes down to surgical skills and technique to put these implants where they are meant to be put! Implants which are the wrong size or imbedded at the wrong angles may lead to quicker wear and tear, loosening and failure. Your orthopaedic surgeon will include all these factors and more during your clinic consultation.
Patient satisfaction increases when they have a stable and painless hip. They are also happy when both legs are the same length! The issue with leg length discrepancy is much lower in patients who have surgery through the anterior approach. As they are lying on their backs during surgery, accurate clinical assessment and x-rays are performed to ensure that both legs are the same length once the implants are in place. This helps to prevent limping and other back pain issues. I always use x-rays during surgery to ensure that implants are the right size and in the right place, as well as to ensure that the legs are of equal lengths! I also use robotic technology (Mako) in some patients to increase the accuracy of hip replacement surgery.
Madam AA is a 48 year old lady who suffered with hip pain for about 4 years. She had hip dysplasia (shallow acetabulum) and this lead to arthritis and torn hip labrum. Key-hole surgery by another surgeon to repair the torn labrum failed and she had to stop exercising, golfing and badminton.
Her right hip xray showed a dysplastic hip with bone-on-bone arthritis as well as cysts in her femoral head and acetabulum.
The x-ray image below showed the total hip implant in the right side and the two parallel green lines show that both legs are the same length after surgery. Robotic surgery takes the guess work out of joint replacements for orthopaedic surgeons!
After her total hip replacement, she returned to golf, exercises and now enjoys travelling the world with her family. Nothing can hold her down now!
Ms BB is a 45 year old lady who suffered with bilateral hip pain for many years. For unknown reasons, she developed avascular necrosis of both her hips. The blood supply to her hip was compromised and bone in her femoral head started to break down. Despite attempts to save her hip by another surgery, her condition continued to deteriorate.
Post-operative x-rays showing implants where her hips used to be. She is now able to live an active lifestyle which all 45 year olds should! Her days are now NOT dependent on how her hips feel when she wakes up! She enjoys taking her dog for walks and recently returned from a holiday in the UK.
Mr CC is a 57 year old Scottish man living in Indonesia. He has been suffering with hip pain for several years. He now had difficulty putting his trouser and socks on. He was unsteady on his feet with stairs and uneven surfaces. His left leg even felt shorter over the years as his hip worsened.
These x-rays show his left arthritic hip before surgery, as well as the implants after the anterior approach total hip replacement.
ConclusionPatients have long benefitted from total hip replacement for many decades. There have been many advances and technological improvements in the materials and dimensions of implants used to ensure these implants out-live patients. Surgical techniques have also improved to match the materials and robotic technologies which are now available for patients. At the end of the day, we want our patients to have an active, meaningful and purposeful life. A total hip replacement may be what you require if you are being held back by a painful and arthritic hip!