The Longevity of a Total Hip Replacement
Most orthopedic surgeons would agree that the goal of a Total Hip replacement is to relieve pain and allow one to ambulate better. It is a very common procedure that most of us have performed during our life in practice. It is a highly effective procedure. A replacement may fail with time due to breakdown or corrosion of the metallic component, loosening of the cement used, infection or other causes. Sooner or later the components of a hip replacement will not be functional. The longer time a patient has benefited from a hip replacement, the higher the rate of failure. Can we discuss the longevity of a Total Hip Replacement?
The longevity of a joint replacement is directly proportional to the engineering of the prosthetic component used. The shape of the prosthetic devices has played an important role in its biomechanical function. Whenever a patient is exploring his/her option to treat the degeneration a hip joint or a tumor or even a fracture, it is important to discuss fully the procedure exploring the benefits and the limitations associated with the operation. We will discuss the functionality of a hip joint, the different causes bringing pain and finally what expectations the patient and the surgeon should have. Post operatively, exercises and activities to restore the musculature around the hip and the extremity will enhance the return to mobility. Often, it is better explained in a pre-op period to build confidence between the surgeon and his/her patient once a full return to regular activities is expected.
In face of a patient presenting with a painful hip joint enabling him to ambulate and forcing the use of external supports or a wheelchair, one can understand how daily living activities can affect life. The hip become stiff and painful rendering any task requesting mobility, difficult. The individual contemplating such procedure often report difficulties in wearing socks because of inability to cross their legs. Medications which have in the past relieved the symptoms, ceased to benefit the patient. A hip replacement become the best option to restore functionality.
Anecdotally, the first total hip replacement was performed in the mid-20th century. This is a successful procedure which over the years has allowed us to perfect the way of approaching the joint to minimize the destruction of the anatomy and to restore the function. Improvements in the techniques and technology have greatly increase the effectiveness of the hip joint. The Agency for Health Research and Quality reports more than 300,000 total hip reconstructions by total hip replacement each year are performed in the United States of America.
The hip joint is the largest joint of the human body. It consists in a ball-and-socket articulation where the ball represents the head of the femur and the socket being a part of the pelvic bone called acetabulum. An articulate cartilage covered the joint surface allowing a smooth motion. The joint is enveloped by a synovial membrane responsible for the lubrication of the joint eliminating any friction during motion. A massive musculature supported by ligaments is re-enforcing the capsule of the joint.
The most common cause of pain and disability in a hip joint is degenerative arthritis. Many arthritic process due to osteoarthritis, Traumatic arthritis or rheumatoid arthritis can involve this joint and interfere with the range of motion:
1- Osteoarthritis is the becoming of all joint with time. It is aged-related and represents the “tear and wear” of the joint. Any patient older than 50 years of age or older will manifest pain or stiffness in relation to this type of arthritis. Some may develop the degeneration earlier than others because of familial predispositions. The cushion provided by the cartilage wears away allowing the bones to rub against each other causing stiffness and later pain and inability to bear weight and ambulate.
2- Autoimmune diseases like Rheumatoid arthritis in which the synovial membrane become diseased, inflamed or thickened, damaging the cartilage in allowing a loss of joint surface. This kind of process represents a group of disorders called inflammatory arthritis.
3- Injuries to the hip joint following a traumatic event like a fracture dislocation, can damage the articular cartilage of the hip joint and lead to stiffness, pain and loss of motion. The blood supply to the femoral head can become deficient after the dislocation limiting the blood supply to the femoral head and causing an Avascular Necrosis. With time, the avascular portion of the femoral head collapse resulting in arthritis. Many diseases like sickle cell and other hemoglobinopaties, like Gaucher’s disease can present with the same lack of blood supply to the femoral head. We have seen this complication in IV drug abusers and infections around the hip joint as well.
4- Many pathologies during infanthood or adolescence can also present with such problem. Kids with Developmental Hip Dysplasia called in the past Congenital hip dysplasia have shown a loss of congruity at the hip joint leading to degenerative process. Slipped capital femoral epiphysis will also present with stiffness and loss of range of motion but with time, osteoarthritis and chondrolysis may set in.
The Total Hip Replacement consists in the removal of damaged cartilage and bone including the femoral head with their replacement by prosthetic components. They are replaced by a metallic stem inserted into the medullary canal of the proximal femur. This stem can be cemented in people with poor bone stock or pressed fitted in younger individuals with healthy bone. The orthopedic surgeon will have also the choice to replace the head with a metallic or ceramic head over the tip of the component. The damaged cartilage of the acetabulum (socket) is also grounded out and replaced with another metallic component which can be stabilized with cement, or screws alone. A spacer is then inserted into the socket to fit the femoral metallic head. This spacer can be of plastic, ceramic or metallic forming a smooth gliding surface.
When a surgical option is finally chosen by a patient to become a recipient of a Total Hip Replacement, it will require a cooperative effort between the patient and his family, the primary care physician and the orthopedic surgeon. Many factors will be analyzed during a consultation once a patient is ready for the replacement:
- Pain and disability rather than age should be considered. We believe that 50 to 80 years of age-group have been considered as typical ages for a hip replacement but recipient should be chosen on an individual basis. Total joint arthroplasty has been performed successfully on teenagers and elderly who have demonstrated pain with every day activities, unrelieved by anti-inflammatory medication. Often, stiffness and inability to ambulate after failed attempts at rehabilitation and ambulation with external support. Radiologic images may show extensive damage or deformity to the hip joint. Occasionally an MRI or a CT scan study may be needed to determine the quality of the bone stock.
Other considerations for an evaluation prior to such procedure, should include:
- The orthopedic consultant to decide whether a hip replacement surgery is the best method to relieve the pain and improve the mobility. He will need to explain the potential risks and complications of such procedure in opening a true dialogue with the patient. The more the patient know, the better he/she will be able to accept and manage the expected changes. In discussing with his/her patient, expectation for daily living activities should be raised.
- One has to understand that material used in the components are subject to wear. So patient’s weight needs to be discussed with exercises programs to minimize wear and loosening of the components. This can be manifested by a painful joint replacement. Avoidance of high impact activities such as jogging, jumping, hiking and even dancing is strongly suggested.
- A dental evaluation to minimize bacteremia from any infection is recommended. If needed, the dental procedures should be carried prior to the planned replacement. Even routine cleaning procedure should be delayed to decrease any risk.
- Urinary problems like an inflamed prostate, should be resolved prior to any surgical treatment. Infections anywhere in the body need to be treated.
- Proper social planning with home therapy will be arranged at discharge from the hospital, after a short stay in hospital first and maybe also a stay in an extended care facility providing help with cooking, bathing, laundry etc. Proper equipment will be also delivered at home like high toilet seat, pillow, dressing etc.
It is important also for the one who become a recipient of a Total Hip Replacement to know about the possibility of failure of the component of the prosthetic device through different processes like dislocation, infection, fracture, mechanical failure with wear of polyethylene, breakage or loosening in the cement fixation etc. Infections are seen in less than 2% of Total hip replacements. Blood clots are common complications especially in the pelvic veins and can be life-threatening. Prophylaxis with anticoagulation therapy and sequential compressive devices or ankle pump will facilitate the vascular flow. Early mobilization is always enforced with precautions when sitting, bending and even sleeping. One has always to discuss those eventualities and the life expectancy of such procedure. The conception that all hip replacements provide a normal pain-free function for the remaining of their life needs to be discouraged fully. A recipient should be also told about the possibility of a leg-length discrepancy.
Studies in the United Kingdom in 2014 have advertised Hip replacement were for people with advanced degenerative arthritis and then a revision was expected in the next 10 years. Nowadays, it is difficult to hear about the longevity of a revised hip replacement’s surgery. The new hip replacement may activate metal detectors at the airports security stand and a special identification card confirming the existence of an artificial hip, is generally provided.
When a recipient asks how long a hip replacement will last, the physician has no other choice than to rely on historical data. Some registries have shown hip replacement lasting 20 to 25 years or less but in fact they are limited by the quality of data presented and the lack of follow up as well, then reflecting a bias. We may rely on annual reports looking at age and sex distribution or implant design presented by different National Joint registries in England, Wales or Sweden etc., to give a plausible answer. Data on a series of 23000 hip replacements have suggested a decrease in the revision rate.
Failure in arthroplasty can be measured in many ways and patients who report failure in one setting may also report success in another. Revision surgery has an uncertain outcome seeing patients and clinicians deciding on the risks and benefits. We need to remember that the goal for the revision surgery is as well to relieve pain. Studies have shown that less than 20% of such patients in need of a revision have not taken the choice. Women were found to have better construct survivorship at all ages than men. Data contributing to a 15-year survival are also available from the Australian and Finnish Registries.
To all who ask so often the pro’s and the cons of a total hip replacement, we have to frankly state that there is not enough information available to predict how long a hip replacement based on searches from the Arthroplasty Registry data from the USA, UK, Finland, Sweden, Denmark Australia etc. These Registries contain almost ¾ of Hip Replacement done in the last 20 years and more than ½ were done because of Degenerative Arthritis. In conclusion, a proponent for a total hip replacement suffering from degenerative arthritis should expect 15 to 20 years from a replacement with all precautions required for the well-being of the prosthetic components
Maxime Coles MD
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8- National Joint Registry for England