Primary Hip Replacement
What is this procedure?
A primary total hip replacement (THR) is a surgical procedure by which an individual’s worn hip is replaced by a prosthesis made from a combination of metal and plastic and/or ceramic. This procedure is typically used as the final measure for the management of hip osteoarthritis that has not responded to conservative therapies. Although considered a major operation, hip replacements have become increasingly common with approximately 72 000 THR procedures done in 2007.
What are the benefits?
Total hip replacement offers a number of advantages, primarily freedom from pain that will usually have plagued the individual for many years. This, along with improved function and mobility will allow an improved quality of life.
Total hip replacements last for at least fifteen years in most people, and can sometimes last for considerably longer than this. Many of hip replacements that were implanted 20 or more years ago and are still working well, so it is expected that the more advanced implants we are using today may last even longer.
What are the risks?
With any major operation there is a chance of bleeding, damage to nerves or blood vessels, and infection. A DVT (deep vein thrombosis) is a blood clot in the leg, and a PE (pulmonary embolus) is a blood clot in the lung; both can be arise after hip replacement. In order to prevent this from happening, graduated compression stockings should be worn and medicine (usually rivaroxaban tablets) are prescribed.
Although results are very good, joint replacements will never be the same as the joints that we are born with.
Some people have persistent pain that does not get better after surgery
After hip replacement, extremes of movement are not recommended as this can lead to dislocations. The time period where there is the greatest risk of this is during the first 3 months after surgery. The most risky activities are twisting movements with the hip flexed (for example when sitting on a chair and bending to pick something up from the floor.) the hip 1 in 10 people will experience ongoing pain after the operation – the reason for this is not always clear.
Some people have the sensation that the operated leg feels longer or shorter than it did before. Naturally, our legs are usually slightly different lengths - up to 1cm difference between left and right is normal and will be tolerated well. There is rarely a difference of greater than 1cm and some of the sensation that people describe may be due to muscles being disturbed by the surgery. Significant differences in leg length can be corrected with the use of an insole.
As with any operation, the risks should be discussed with the surgeon and the anaesthetist before deciding to go ahead.
Who should consider this operation?
THR should be considered if you have severe hip arthritis, and your symptoms affect your quality of life, despite nonoperative measures. The benefits of the operation should be deemed to outweigh any risks. Therefore you should only make the decision to go ahead with surgery after careful consideration, and after other treatments have been exhausted. This is particularly so in individuals with poor general health, as the risks of surgery are increased.
Preoperative preparation and evaluation
Once a decision to have a total hip replacement has been made, you will be required to come into hospital days or weeks before the actual procedure for a preoperative evaluation by the surgeon and members of the multidisciplinary team. During this time the team will take a medical history, perform a physical examination and carry out relevant investigations to ensure that you are fit enough to undergo the operation. These investigations usually include blood tests, urine tests and a heart trace (also known as an electrocardiogram or ECG).
If you smoke, you should stop smoking for as long as possible (at least 2 weeks) prior to the operation and should maintain this after the operation to reduce the chances of having a chest infection or wound healing problem. Certain medications should also be stopped prior to the operation, and you will be informed about these by the pre-assessment team. Certain medications and conditions may require you to be admitted into hospital 1-2 days prior to the operation. Arrangements for this will also be made during the preoperative evaluation.
You will be advised at this time on how to prepare your home circumstances for when you can be discharged from hospital. Home support may be arranged if you live alone and/or are deemed to require additional help.
It is important that you are as fit as possible prior to the operation to ensure the best possible outcome. The more muscle strength that you have around your hip before the operation the better you will cope afterwards. A physiotherapist should also be present at the preoperative clinic to advise you on exercises you can do to help strengthen the hip. You are also advised to remain as active and mobile as possible, and activities such as walking and swimming are encouraged. Finally the physiotherapist may also use this opportunity to issue and teach you how to use crutches. This helps to speed the recovery process.
What happens in the postoperative period?
Our understanding of hip replacement surgery and postoperative management has improved considerably over the years. As a result, patients who undergo a total hip replacement are normally discharged from hospital within 5 days of the procedure.
Immediately after the operation you will be taken to a recovery room until you are fully awake and the anaesthetist is happy that your condition is stable. At this point you will be transferred back to the ward. Pain is common in the early stages after surgery and you will therefore be offered adequate pain relief to manage your symptoms and allow you to commence early rehabilitation. Many surgeons now advocate an enhanced / accelerated recovery programme. This aims to have you standing and mobilizing within 12-18 hours of surgery. A physiotherapist will see you regularly during your stay in hospital to help with mobilizing, walking up and down stairs, and provide advice on strengthening exercises. The physiotherapist will also offer general advice to help manage pain and swelling.
There are certain activities and movements that must be avoided following a total hip replacement. These include bending the hip beyond 90 degrees (e.g. squatting and sitting in a low chair), and crossing legs. Both of these movements increase the risk of hip dislocation, particularly in the early stages after surgery. The physiotherapist should issue advice on these precautions. An occupational therapist (OT) will advise you on the correct height of seating. The OT will also assess your function undertaking a number of daily tasks and may issue equipment to help you manage at home.
The time taken to recover depends on many factors including your general health, preoperative function and the condition of other joints. After discharge you will continue to be followed up to ensure your recovery is going well. District nurses will manage changing of dressings and removal of skin clips or stitches and there will be an outpatient appointment at around 6 weeks after the operation. You may also be referred for outpatient physiotherapy if it is felt you would benefit from additional input. It commonly takes six to twelve months to experience the full benefits of surgery.