Hip replacement is a
surgical
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
procedure in which the
hip
In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint.
The hip region is ...
joint is replaced by a prosthetic
implant
Implant can refer to:
Medicine
*Implant (medicine), or specifically:
** Brain implant
** Breast implant
**Buttock implant
**Cochlear implant
**Contraceptive implant
**Dental implant
** Fetal tissue implant
**Implantable cardioverter-defibrillator ...
, that is, a hip prosthesis. Hip replacement surgery can be performed as a total replacement or a hemi (half) replacement. Such
joint replacement
Replacement arthroplasty (from Greek ''arthron'', joint, limb, articulate, + ''plassein'', to form, mould, forge, feign, make an image of), or joint replacement surgery, is a procedure of orthopedic surgery in which an arthritic or dysfunctional j ...
orthopaedic surgery
Orthopedic surgery or orthopedics ( alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...
is generally conducted to relieve
arthritis
Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...
pain
Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
or in some
hip fracture
A hip fracture is a break that occurs in the upper part of the femur (thigh bone). Symptoms may include pain around the hip, particularly with movement, and shortening of the leg. Usually the person cannot walk.
They most often occur as a res ...
s. A total hip replacement (total hip arthroplasty or THA) consists of replacing both the
acetabulum
The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.
Structure
There are three bones of the ''os coxae'' (hip bone) that c ...
and the femoral head while
hemiarthroplasty
Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip prosthesis. Hip replacement surgery can be performed as a total replacement or a hemi (half) replacement. Such joint replacement or ...
generally only replaces the femoral head. Hip replacement is one of the most common orthopaedic operations, though patient satisfaction varies widely. Approximately 58% of total hip replacements are estimated to last 25 years. The average cost of a total hip replacement in 2012 was $40,364 in the United States, and about $7,700 to $12,000 in most European countries.
Medical uses
Total hip replacement is most commonly used to treat joint failure caused by
osteoarthritis
Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...
. Other indications include
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
,
avascular necrosis
Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop which may limit the ability to move. Co ...
,
traumatic arthritis
Trauma most often refers to:
*Major trauma, in physical medicine, severe physical injury caused by an external source
*Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event
*Traumatic inju ...
,
protrusio acetabuli
''Protrusio acetabuli'' is an uncommon defect of the ''acetabulum'', the socket that receives the femoral head to make the hip joint. The hip bone of the pelvic bone/girdle is composed of three bones, the ilium (bone), ilium, the ischium and the p ...
, certain
hip fracture
A hip fracture is a break that occurs in the upper part of the femur (thigh bone). Symptoms may include pain around the hip, particularly with movement, and shortening of the leg. Usually the person cannot walk.
They most often occur as a res ...
s, benign and malignant
bone tumor
A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroi ...
s, arthritis associated with
Paget's disease,
ankylosing spondylitis
Ankylosing spondylitis (AS) is a type of arthritis characterized by long-term inflammation of the joints of the spine typically where the spine joins the pelvis. Occasionally areas affected may include other joints such as the shoulders or hip ...
and
juvenile rheumatoid arthritis
Juvenile may refer to:
*Juvenile status, or minor (law), prior to adulthood
* Juvenile (organism)
*Juvenile (rapper) (born 1975), American rapper
* ''Juvenile'' (2000 film), Japanese film
* ''Juvenile'' (2017 film)
*Juvenile (greyhounds), a greyh ...
. The aims of the procedure are pain relief and improvement in hip function. Hip replacement is usually considered only after other therapies, such as
physical therapy
Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
and pain medications, have failed.
Risks
Risks and complications in hip replacement are similar to those associated with all
joint replacements. They can include infection, dislocation, limb length inequality, loosening, impingement, osteolysis, metal sensitivity, nerve palsy, chronic pain and death.
Weight loss surgery
Bariatric surgery (or weight loss surgery) includes a variety of procedures performed on people who are obese. Long term weight loss through the standard of care procedures ( Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion ...
before a hip replacement does not appear to change outcomes.
Dislocation
![Hip prosthesis liner creep and wear](https://upload.wikimedia.org/wikipedia/commons/d/d9/Hip_prosthesis_liner_creep_and_wear.png)
Dislocation (the ball coming out of the socket) is the most common complication. The most common causes vary by the duration since the surgery.
Hip prosthesis
dislocation
In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to sl ...
mostly occurs in the first three months after insertion, mainly because of incomplete scar formation and relaxed soft tissues.
It takes eight to twelve weeks for the soft tissues injured or cut during surgery to heal. The chance of this is diminished if less tissue is cut, if the cut tissue is repaired and if large diameter head balls are used.
Dislocations occurring between three months and five years after insertion usually occur due to malposition of the components, or dysfunction of nearby muscles.
[
Risk factors of late dislocation (after five years) mainly include:][
* Female sex
* Younger age
* Previous ]subluxation
A subluxation is an incomplete or partial dislocation of a joint or organ.
According to the World Health Organization (WHO), a subluxation is a "significant structural displacement", and is therefore always visible on static imaging studies, suc ...
without complete dislocation
* Previous trauma
* Substantial weight loss
* Recent onset or progression of dementia
Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...
or a neurological disorder
A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakn ...
* Malposition of the cup
* Liner wear, particularly when it allows head movement of more than 2 mm within the cup compared to its original position
* Prosthesis loosening with migration
Surgeons who perform more operations tend to have fewer dislocations. An anterior approach seems to lower dislocation rates when small diameter heads are used, but that benefit has not been shown when compared to modern posterior incisions with the use of larger diameter heads. The use of larger diameter head size in itself decreases dislocation risk, even though this correlation is only found in head sizes up to 28 mm: larger heads do not additional decreases in dislocation rate. Keeping the leg out of certain positions during the first few months after surgery further reduces risk.
Infection
Infection is one of the most common causes for revision of a total hip replacement. The incidence of infection in primary hip replacement is 1% or less in the United States. Risk factors for infection include obesity, diabetes, smoking, immunosuppressive medications or diseases, and history of infection.
Limb length inequality
Most adults have a limb length inequality of 0–2 cm which causes no deficits. It is common for people to sense a larger limb length inequality after total hip replacement. Sometimes the leg seems long immediately after surgery when in fact both are equal length. An arthritic hip can develop contractures that make the leg behave as if it is short. When these are relieved with replacement surgery and normal motion and function are restored, the body feels that the limb is now longer than it was. This feeling usually subsides by six months after surgery as the body adjusts to the new hip joint. The cause of this feeling is variable, and usually related to abductor muscle weakness, pelvic obliquity, and minor lengthening of the hip during surgery (<1 cm) to achieve stability and restore the joint to pre-arthritic mechanics. If the limb length difference remains bothersome to the patient more than six months after surgery, a shoe lift can be used. Only in extreme cases is surgery required for correction. The perceived difference in limb length for a patient after surgery is a common cause for lawsuits against the healthcare provider.
Fracture
Intraoperative fractures may occur. After surgery, bones with internal fixation devices in situ are at risk of periprosthetic Periprosthetic in medicine refers to a structure in close relation to an implant.
Clinically it can refer to:
*Bone fracture or 'periprosthetic fracture' around an artificial joint, e.g. after a knee replacement
*infection around an artificial jo ...
fractures at the end of the implant, an area of relative mechanical stress. Post-operative femoral fractures are graded by the Vancouver classification The Vancouver classification is a grading system used in orthopaedics to determine management of post-operative periprosthetic femoral fractures following a hip arthroplasty. It is named for the city Vancouver, home to the University of British C ...
.
Vein thrombosis
Venous thrombosis
Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to ...
such as deep vein thrombosis
Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
and pulmonary embolism
Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain p ...
are relatively common following hip replacement surgery. Standard treatment with anticoagulant
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...
s is for 7–10 days; however, treatment for 21+ days may be superior. Extended-duration anticoagulants (up to 35 days following surgery) may prevent VTE in people undergoing hip replacement surgery. Other research suggested that anticoagulants in otherwise healthy patients undergoing a so-called fast track protocol with hospital stays under five days, might only be necessary while in the hospital. Emerging evidence supports the use of aspirin for venous thromboembolism prophylaxis. Large randomised control trials suggested that aspirin is not inferior to low-molecular weight heparins
Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the treatm ...
and rivaroxaban
Rivaroxaban, sold under the brand name Xarelto among others, is an anticoagulant medication (blood thinner) used to treat and prevent blood clots. Specifically it is used to treat deep vein thrombosis and pulmonary emboli and prevent blood clo ...
. However, aspirin may not be appropriate in all cases, especially for patients who have additional risk factors for venous thromboembolisms or may have an inadequate response to aspirin.
Some physicians and patients may consider having an ultrasonography for deep vein thrombosis after hip replacement.[, which cites
* ] However, this kind of screening should only be done when indicated because to perform it routinely would be unnecessary health care
Unnecessary health care (overutilization, overuse, or overtreatment) is health care provided with a higher volume or cost than is appropriate.
In the United States, where health care costs are the highest as a percentage of GDP, overuse was the ...
.
Intermittent pneumatic compression Intermittent pneumatic compression is a therapeutic technique used in medical devices that include an air pump and inflatable auxiliary sleeves, gloves or boots in a system designed to improve venous circulation in the limbs of patients who have ed ...
(IPC) devices are sometimes used for prevention of blood clots following total hip replacement.
Osteolysis
Many long-term problems with hip replacements are the result of osteolysis
Osteolysis is an active resorption of bone matrix by osteoclasts and can be interpreted as the reverse of ossification. Although osteoclasts are active during the natural formation of healthy bone the term "osteolysis" specifically refers to a path ...
. This is the loss of bone caused by the body's reaction to polyethylene wear debris, fine bits of plastic that wear off the cup liner over time. An inflammatory process causes bone resorption that may lead to subsequent loosening of the hip implants and even fractures in the bone around the implants. Ceramic bearing surfaces may eliminate the generation of wear particles. Metal cup liners joined with metal heads (metal-on-metal hip arthroplasty) were developed for similar reasons. In the lab these show excellent wear characteristics and benefit from a different mode of lubrication.
Highly cross-linked polyethylene plastic liners experience significantly reduced plastic wear debris. The newer ceramic and metal prostheses may not have long-term performance records. Ceramic piece breakage can lead to catastrophic failure. This occurs in about 2% of implants. They may also cause an audible, high pitched squeaking noise with activity. Metal-on-metal arthroplasty can release metal debris into the body. Highly cross linked polyethylene is not as strong as regular polyethylene. These plastic liners can crack or break free of the metal shell that holds them.
Loosening
On radiography, it is normal to see thin radiolucent areas of less than 2 mm around hip prosthesis components, or between a cement mantle and bone. These may indicate loosening of the prosthesis if they are new or changing, while areas greater than 2 mm may be harmless if they are stable. The most important prognostic factors of cemented cups are absence of radiolucent lines in DeLee and Charnley zone I, as well as adequate cement mantle thickness. In the first year after insertion of uncemented femoral stems, it is normal to have mild subsidence (less than 10 mm). The direct anterior approach has been shown to itself be a risk factor for early femoral component loosening.
Metal sensitivity
Concerns were raised in the early 2000s regarding metal sensitivity and the potential dangers of metal particulate debris from hip prostheses, including the development of ''pseudotumors'', soft tissue
Soft tissue is all the tissue in the body that is not hardened by the processes of ossification or calcification such as bones and teeth. Soft tissue connects, surrounds or supports internal organs and bones, and includes muscle, tendons, ligam ...
masses containing necrotic tissue, around the hip joint. It appears these masses were more common in women, and these patients showed a higher level of iron in the blood. The cause was then unknown, and was probably multifactorial. There may have been a toxic reaction to an excess of particulate metal wear debris or a hypersensitivity reaction to a "normal" amount of metal debris.
Metal hypersensitivity is a well-established phenomenon and is not uncommon, affecting about 10–15% of the population. Skin contact with certain metals can cause immune reactions such as hives
Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...
, eczema
Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...
, redness and itching. Although little is known about the short- and long-term pharmacodynamics and bioavailability of circulating metal degradation products ''in vivo'', there have been many reports of immunologic-type responses temporally associated with implantation of metal components. Individual case reports link immune hypersensitivity reactions with adverse performance of metallic cardiovascular, orthopedic and plastic surgical and dental implants.[
]
Metal toxicity
Most hip replacements consist of cobalt and chromium alloys, or titanium. Stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
is no longer used. Any metal implant releases its constituent ions
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
into the blood. Typically, these are excreted in the urine, but in certain individuals the ions can accumulate in the body. In implants which involve metal-on-metal contact, microscopic fragments of cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...
and chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
can be absorbed into the person's bloodstream. There are reports of cobalt toxicity with hip replacement, particularly metal-on-metal hip replacements, which are no longer in use.[
Use of metal-on-metal hip replacements from the 1970s was discontinued in the 1980s and 1990s, particularly after the discovery of aseptic lymphocyte-dominant vasculitis-associated lesions (ALVAL). However, the FDA's 510k approval process allowed companies to have new and "improved" metal-on-metal hips approved without much clinical testing. Some people with these prostheses experienced similar reactions to the metal debris as occurred in the 20th century; some devices were recalled.
]
Nerve palsy
Post operative sciatic nerve
The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals which is the largest branch of the sacral plexus and runs alongside the hip joint and down the lower limb. It is the longest and widest si ...
palsy is another possible complication. The frequency of this complication is low. Femoral nerve
The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee.
Structure
The femoral nerve is the major nerve supplying the anterior compartment of the thigh. It is the largest ...
palsy is another, but much rarer, complication. Both of these will typically resolve over time, but the healing process is slow. Patients with pre-existing nerve injury are at greater risk of experiencing this complication and are also slower to recover.
Chronic pain
A few patients who have had a hip replacement suffer chronic pain after the surgery. Groin pain can develop if the muscle that raises the hip (iliopsoas
The iliopsoas muscle (; from lat, ile, lit=groin and grc, ψόᾱ, psóā, muscles of the loins) refers to the joined psoas major and the iliacus muscles. The two muscles are separate in the abdomen, but usually merge in the thigh. They are usua ...
) rubs against the edge of the acetabular cup. Bursitis can develop at the trochanter where a surgical scar crosses the bone, or if the femoral component used pushes the leg out to the side too far. Also some patients can experience pain in cold or damp weather. Incision made in the front of the hip (anterior approach) can cut a nerve running down the thigh leading to numbness in the thigh and occasionally chronic pain at the point where the nerve was cut (a neuroma).
Death
The rate of perioperative mortality
Perioperative mortality has been defined as any death, regardless of cause, occurring within 30 days after surgery in or out of the hospital. Globally, 4.2 million people are estimated to die within 30 days of surgery each year. An important consid ...
for elective hip replacements is significantly less than 1%.
Metal-on-metal hip implant failure
By 2010, reports in the orthopaedic literature increasingly cited the problem of early failure of metal-on-metal prostheses in a small percentage of patients. Failures may have related to the release of minute metallic particles or metal ions from wear
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in m ...
on the implants, causing pain and disability severe enough to require revision surgery in 1–3% of patients. Design deficits of some prothesis models, especially with heat-treated alloys and a lack of specialized surgical experience, accounted for most of the failures. In 2010, surgeons at medical centers such as the Mayo Clinic
The Mayo Clinic () is a nonprofit American academic medical center focused on integrated health care, education, and research. It employs over 4,500 physicians and scientists, along with another 58,400 administrative and allied health staff, ...
reported curtailing their use of metal-on-metal implants by 80 percent over the previous year, in favor of those made from other materials, such as combinations of metal and plastic. The cause of these failures remains controversial, and may include both design factors, operative technique factors, and factors related to patient immune response
An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...
. In the United Kingdom, the Medicines and Healthcare products Regulatory Agency
The Medicines and Healthcare products Regulatory Agency (MHRA) is an executive agency of the Department of Health and Social Care in the United Kingdom which is responsible for ensuring that medicines and medical devices work and are acceptably ...
commenced an annual monitoring regime for metal-on-metal hip replacement patients from May 2010. Data which are shown in The Australian Orthopaedic Association's 2008 National Joint replacement registry A joint replacement registry is a system of collecting information of arthroplasty outcomes at a population (often national) level, in order to provide an evidence-base for safe and effective treatment options.
Background
The UK registry, the N ...
, a record of nearly every hip implanted in that country over the previous 10 years, tracked 6,773 BHR (Birmingham Hip Resurfacing) hips and found that less than 0.33% may have been revised due to the patient's reaction to the metal component. Other, similar, metal-on-metal designs have not fared as well, with some reports showing that 76–100% of people with these metal-on-metal implants with aseptic implant failures and needing revision surgery also had histological evidence of inflammation, accompanied by extensive lymphocyte infiltrates characteristic of delayed-type hypersensitivity reactions. It is not clear to what extent this phenomenon negatively affects orthopedic implant patients. However, for patients presenting with signs of allergic reaction, testing for sensitivity should be conducted. Removal of the device should be considered, since removal may alleviate the symptoms. Patients who have allergic reactions to alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
jewelry are more likely to have reactions to orthopedic implants. There is increasing awareness of the phenomenon of metal sensitivity, and many surgeons now take this into account when planning which implant is optimal for each patient.
On March 12, 2012, ''The Lancet
''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823.
The journal publishes original research articles, ...
'' published a study, based on data from the National Joint Registry of England and Wales, finding that metal-on-metal hip implants failed at much higher rates than other types of hip implants, and calling for a ban on all metal-on-metal hip prostheses. The analysis of 402,051 hip replacements showed that 6.2% of metal-on-metal hip implants had failed within five years, compared to 1.7% of metal-on-plastic and 2.3% of ceramic-on-ceramic hip implants. Each increase in head size of metal-on-metal hip implants was associated with a 2% increase in failure rate. Surgeons of the British Hip Society recommended that large head metal-on-metal implants should no longer be implanted.
On February 10, 2011, the U.S. FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
issued an advisory on metal-on-metal hip implants, stating it was continuing to gather and review all available information about metal-on-metal hip systems. On June 27–28, 2012, an advisory panel met to decide whether to impose new standards, taking into account findings of the study in ''The Lancet''. No new standards, such as routine checking of blood levels of metal ions, were set, but guidance was updated. The U.S. FDA does not require hip implants to be tested in clinical trials before they can be sold in the U.S. Instead, companies making new hip implants only need to prove that they are "substantially equivalent" to other hip implants already on the market. The exception is metal-on-metal implants, which were not tested in clinical trials, but, due to the high revision rate of metal-on-metal hips, the FDA has stated that, in the future, clinical trials will be required for approval, and that post-market studies will be required to keep metal-on-metal hip implants on the market.
Modern process
The modern artificial joint owes much to the 1962 work of Sir John Charnley
Sir John Charnley, (29 August 1911 – 5 August 1982) was an English orthopaedic surgeon. He pioneered the hip replacement operation, which is now one of the most common operations both in the UK and elsewhere in the world, and created the ...
at Wrightington Hospital. His work in the field of tribology
Tribology is the science and engineering of interacting surfaces in relative Motion (physics), motion. It includes the study and application of the principles of friction, lubrication and wear. Tribology is highly interdisciplinary, drawing on m ...
resulted in a design that almost completely replaced the other designs by the 1970s. Charnley's design consisted of three parts:
# stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
one-piece femoral stem and head
# polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...
(originally Teflon
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemou ...
), acetabular component, both of which were fixed to the bone using
# PMMA PMMA may refer to:
* para-Methoxymethamphetamine, a stimulant drug
* Philippine Merchant Marine Academy
The Philippine Merchant Marine Academy ( fil, Akademiya sa Bapor Pangkalakalan ng Pilipinas) also referred to by its acronym PMMA) is a ma ...
(acrylic) bone cement
Bone cements have been used very successfully to anchor artificial joints (hip joints, knee joints, shoulder and elbow joints) for more than half a century. Artificial joints (referred to as prostheses) are anchored with bone cement. The bone ce ...
The replacement joint, which was known as the Low Friction Arthroplasty
Arthroplasty (literally " e-orming of joint") is an orthopedic surgical procedure where the articular surface of a musculoskeletal joint is replaced, remodeled, or realigned by osteotomy or some other procedure. It is an elective procedure that i ...
, was lubricated with synovial fluid
Synovial fluid, also called synovia, elp 1/sup> is a viscous, non-Newtonian fluid found in the cavities of synovial joints. With its egg white–like consistency, the principal role of synovial fluid is to reduce friction between the articular ...
. The small femoral head () was chosen for Charnley's belief that it would have lower friction against the acetabular component and thus wear out the acetabulum more slowly. Unfortunately, the smaller head dislocated more easily. Alternative designs with larger heads such as the Mueller prosthesis were proposed. Stability was improved, but acetabular wear and subsequent failure rates were increased with these designs. The Teflon acetabular components of Charnley's early designs failed within a year or two of implantation. This prompted a search for a more suitable material. A German salesman showed a polyethylene gear sample to Charnley's machinist, sparking the idea to use this material for the acetabular component. The UHMWPE
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. T ...
acetabular component was introduced in 1962. Charnley's other major contribution was to use polymethylmethacrylate (PMMA) bone cement to attach the two components to the bone. For over two decades, the Charnley Low Friction Arthroplasty, and derivative designs were the most used systems in the world. It formed the basis for all modern hip implants. An example can be seen at the Science Museum, London.
The Exeter hip stem was developed in the United Kingdom during the same time as the Charnley device. Its development occurred following a collaboration between Orthopaedic Surgeon Robin Ling
Robin Sydney Mackwood Ling, (7 September 1927 – 9 October 2017) was an English surgeon who invented the Exeter hip system, a hip replacement. As an orthopaedic surgeon at the Princess Elizabeth orthopaedic hospital, Exeter, he co-operated wi ...
and University of Exeter
The University of Exeter is a public university , public research university in Exeter, Devon, England, United Kingdom. Its predecessor institutions, St Luke's College, Exeter School of Science, Exeter School of Art, and the Camborne School of Min ...
engineer Clive Lee
Alan John Clive Lee (18 February 1939 – 2 November 2021) was a British design engineer known for co-creating the Exeter hip system in association with orthopaedic surgeon, Robin Ling. Unlike any other hip replacement, the collarless polishe ...
and it was first implanted at the Princess Elizabeth Orthopaedic Hospital in Exeter in 1970. The Exeter Hip is a cemented device, but with a slightly different stem geometry. Both designs have shown excellent long-term durability when properly placed and are still widely used in slightly modified versions.
Early implant designs had the potential to loosen from their attachment to the bones, typically becoming painful ten to twelve years after placement. In addition, erosion of the bone around the implant was seen on x-rays. Initially, surgeons believed this was caused by an abnormal reaction to the cement holding the implant in place. That belief prompted a search for an alternative method to attach the implants. The Austin Moore device had a small hole in the stem into which bone graft was placed before implanting the stem. It was hoped bone would then grow through the window over time and hold the stem in position. Success was unpredictable and the fixation not very robust. In the early 1980s, surgeons in the United States applied a coating of small beads to the Austin Moore device and implanted it without cement. The beads were constructed so that gaps between beads matched the size of the pores in native bone. Over time, bone cells from the patient would grow into these spaces and fix the stem in position. The stem was modified slightly to fit more tightly into the femoral canal, resulting in the Anatomic Medullary Locking (AML) stem design. With time, other forms of stem surface treatment and stem geometry have been developed and improved.
Initial hip designs were made of a one-piece femoral component and a one-piece acetabular component. Current designs have a femoral stem and separate head piece. Using an independent head allows the surgeon to adjust leg length (some heads seat more or less onto the stem) and to select from various materials from which the head is formed. A modern acetabulum component is also made up of two parts: a metal shell with a coating for bone attachment and a separate liner. First the shell is placed. Its position can be adjusted, unlike the original cemented cup design which are fixed in place once the cement sets. When proper positioning of the metal shell is obtained, the surgeon may select a liner made from various materials.
To combat loosening caused by polyethylene wear debris, hip manufacturers developed improved and novel materials for the acetabular liners. Ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
heads mated with regular polyethylene liners or a ceramic liner were the first significant alternative. Metal liners to mate with a metal head were also developed. At the same time these designs were being developed, the problems that caused polyethylene wear were determined and manufacturing of this material improved. Highly crosslinked UHMWPE was introduced in the late 1990s. The most recent data comparing the various bearing surfaces has shown no clinically significant differences in their performance. Potential early problems with each material are discussed below. Performance data after 20 or 30 years may be needed to demonstrate significant differences in the devices. All newer materials allow use of larger diameter femoral heads. Use of larger heads significantly decreases the chance of the hip dislocating, which remains the greatest complication of the surgery.
When available implants are used, cemented stems tend to have a better longevity than uncemented stems. No significant difference is observed in the clinical performance of the various methods of surface treatment of uncemented devices. Uncemented stems are selected for patients with good quality bone that can resist the forces needed to drive the stem in tightly. Cemented devices are typically selected for patients with poor quality bone who are at risk of fracture during stem insertion. Cemented stems are less expensive due to lower manufacturing cost, but require good surgical technique to place them correctly. Uncemented stems can cause pain with activity in up to 20% of patients during the first year after placement as the bone adapts to the device. This is rarely seen with cemented stems.
Techniques
There are several incisions, defined by their relation to the gluteus medius. The approaches are posterior (Moore), lateral (Hardinge or Liverpool), antero-lateral (Watson-Jones), anterior (Smith-Petersen) and greater trochanter
The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system.
It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Stan ...
osteotomy. There is no compelling evidence in the literature for any particular approach.
Posterior approach
The ''posterior'' (''Moore'' or ''Southern'') ''approach'' accesses the joint and capsule through the back, taking piriformis muscle
The piriformis muscle () is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.
The piriformis muscle has its origin upon the front surface of the sacrum, and inse ...
and the short external rotators of the femur. This approach gives excellent access to the acetabulum and femur and preserves the hip abductors and thus minimizes the risk of abductor dysfunction post operatively. It has the advantage of becoming a more extensile approach if needed. Critics cite a higher dislocation rate, although repair of the capsule, piriformis and the short external rotators along with use of modern large diameter head balls reduces this risk. Limited evidence suggests that the posterior approach may cause less nerve damage.
Lateral approach
The ''lateral approach'' is also commonly used for hip replacement. The approach requires elevation of the hip abductors (gluteus medius
The gluteus medius, one of the three gluteal muscles, is a broad, thick, radiating muscle. It is situated on the outer surface of the pelvis.
Its posterior third is covered by the gluteus maximus, its anterior two-thirds by the gluteal aponeu ...
and gluteus minimus
The gluteus minimus, or glutæus minimus, the smallest of the three gluteal muscles, is situated immediately beneath the gluteus medius.
Structure
It is fan-shaped, arising from the outer surface of the ilium, between the anterior and infer ...
) to access the joint. The abductors may be lifted up by osteotomy of the greater trochanter and reapplying it afterwards using wires (as per Charnley), or may be divided at their tendinous portion, or through the functional tendon (as per Hardinge) and repaired using sutures. Although this approach has a lower dislocation risk than the posterior approach, critics note that occasionally the abductor muscles do not heal back on, leading to pain and weakness which is often very difficult to treat.
Antero-lateral approach
The ''anterolateral approach'' develops the interval between the tensor fasciae latae
The tensor fasciae latae (or tensor fasciæ latæ or, formerly, tensor vaginae femoris) is a muscle of the thigh. Together with the gluteus maximus, it acts on the iliotibial band and is continuous with the iliotibial tract, which attaches to the ...
and the gluteus medius. The Gluteus medius, gluteus minimus and hip capsule are detached from the anterior (front) for the greater trochanter and femoral neck and then repaired with heavy suture after the replacement of the joint.
Anterior approach
The ''anterior approach'' uses an interval between the sartorius muscle
The sartorius muscle () is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the Anterior compartment of thigh, anterior compartment.
Structure
The sartorius muscle originates f ...
and tensor fasciae latae. Dr. Joel Matta and Dr. Bert Thomas have adapted this approach, which was commonly used for pelvic fracture repair surgery, for use when performing hip replacement. When used with older hip implant systems that had a small diameter head, dislocation rates were reduced compared to surgery performed through a posterior approach. With modern implant designs, dislocation rates are similar between the anterior and posterior approaches. The anterior approach has been shown in studies to variably improve early functional recovery, with possible complications of femoral component loosening and early revision compared to other approaches.
Minimally invasive approaches
The dual incision approach and other minimally invasive surgery seeks to reduce soft tissue damage through reducing the size of the incision. However, component positioning accuracy and visualization of the bone structures can be significantly impaired as the approaches get smaller. This can result in unintended fractures and soft tissue injury. The majority of current orthopedic surgeons use a "minimally invasive" approach compared to traditional approaches which were quite large comparatively.
Computer-assisted surgery
Computer-assisted surgery (CAS) represents a surgical concept and set of methods, that use computer technology for surgical planning, and for guiding or performing surgical interventions. CAS is also known as computer-aided surgery, computer-assist ...
and robotic surgery techniques are also available to guide the surgeon to provide enhanced component accuracy. Several commercial CAS and robotic systems are available for use worldwide. Improved patient outcomes and reduced complications have not been demonstrated when these systems are used when compared to standard techniques.
Implants
The prosthetic implant used in hip replacement consists of three parts: the acetabular cup, the femoral component, and the articular interface. Options exist for different people and indications. The evidence for a number of newer devices is not very good, including: ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups. Correct selection of the prosthesis is important.
Acetabular cup
The acetabular cup is the component which is placed into the acetabulum
The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.
Structure
There are three bones of the ''os coxae'' (hip bone) that c ...
(hip socket). Cartilage and bone are removed from the acetabulum and the acetabular cup is attached using friction or cement. Some acetabular cups are one piece, while others are modular. One-piece (monobloc) shells are either ultra-high-molecular-weight polyethylene
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. T ...
(UHMWPE) or metal, they have their articular surface machined on the inside surface of the cup and do not rely on a locking mechanism to hold a liner in place. A monobloc polyethylene cup is cemented in place while a metal cup is held in place by a metal coating on the outside of the cup. Modular cups consist of two pieces, a shell and liner. The shell is made of metal; the outside has a porous coating while the inside contains a locking mechanism designed to accept a liner. Two types of porous coating used to form a friction fit are sintered
Clinker nodules produced by sintering
Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction.
Sintering happens as part of a manufacturing ...
beads and a foam metal design to mimic the trabeculae of cancellous bone and initial stability is influenced by under-reaming and insertion force. Permanent fixation is achieved as bone grows onto or into the porous coating. Screws can be used to lag the shell to the bone providing even more fixation. Polyethylene liners are placed into the shell and connected by a rim locking mechanism; ceramic and metal liners are attached with a Morse taper
Morse may refer to:
People
* Morse (surname)
* Morse Goodman (1917-1993), Anglican Bishop of Calgary, Canada
* Morse Robb (1902–1992), Canadian inventor and entrepreneur
Geography Antarctica
* Cape Morse, Wilkes Land
* Mount Morse, Church ...
.
Femoral component
The femoral component is the component that fits in the femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...
(thigh bone). Bone is removed and the femur is shaped to accept the femoral stem with attached prosthetic femoral head (ball). There are two types of fixation: cemented and uncemented. Cemented stems use acrylic bone cement
Bone cements have been used very successfully to anchor artificial joints (hip joints, knee joints, shoulder and elbow joints) for more than half a century. Artificial joints (referred to as prostheses) are anchored with bone cement. The bone ce ...
to form a mantle between the stem and to the bone. Uncemented stems use friction, shape and surface coatings to stimulate bone to remodel and bond to the implant. Stems are made of multiple materials (titanium, cobalt chromium, stainless steel, and polymer composites) and they can be monolithic or modular. Modular components consist of different head dimensions and/or modular neck orientations; these attach via a taper similar to a Morse taper
Morse may refer to:
People
* Morse (surname)
* Morse Goodman (1917-1993), Anglican Bishop of Calgary, Canada
* Morse Robb (1902–1992), Canadian inventor and entrepreneur
Geography Antarctica
* Cape Morse, Wilkes Land
* Mount Morse, Church ...
. These options allow for variability in leg length, offset and version. Femoral heads are made of metal or ceramic material. Metal heads, made of cobalt chromium for hardness, are machined to size and then polished to reduce wear of the socket liner. Ceramic heads are more smooth than polished metal heads, have a lower coefficient of friction than a cobalt chrome head, and in theory will wear down the socket liner more slowly. As of early 2011, follow-up studies in patients have not demonstrated significant reductions in wear rates between the various types of femoral heads on the market. Ceramic implants are more brittle and may break after being implanted.
Articular interface
The articular interface is not part of either implant, rather it is the area between the acetabular cup and femoral component. The articular interface of the hip is a simple ball and socket joint. Size, material properties and machining tolerances
Engineering tolerance is the permissible limit or limits of variation in:
# a physical dimension;
# a measured value or physical property of a material, manufacturing, manufactured object, system, or service;
# other measured values (such as t ...
at the articular interface can be selected based on patient demand to optimise implant function and longevity whilst mitigating associated risks. The interface size is measured by the outside diameter of the head or the inside diameter of the socket. Common sizes of femoral heads are , and . While was common in the first modern prostheses, now even larger sizes are available from 38 to over 54 mm. Larger-diameter heads lead to increased stability and range of motion whilst lowering the risk of dislocation. At the same time they are also subject to higher stresses such as friction and inertia. Different combinations of materials have different physical properties which can be coupled to reduce the amount of wear debris generated by friction. Typical pairings of materials include metal on polyethylene (MOP), metal on crosslinked polyethylene (MOXP), ceramic on ceramic (COC), ceramic on crosslinked polyethylene (COXP), and metal on metal (MOM). Each combination has different advantages and disadvantages.
Dual mobility hip replacements reduce the risk of dislocation.
Configuration
Post-operative projectional radiography
Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by x-ray radiation. The image acquisition is generally performed by radiographers, and the images ...
is routinely performed to ensure proper configuration of hip prostheses.
The direction of the acetabular cup influences the range of motion of the leg, and also affects the risk of dislocation.[ For this purpose, the ''acetabular inclination'' and the ''acetabular anteversion'' are measurements of cup angulation in the ]coronal plane
The coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes.
Details
The coronal plane is an example of a longitud ...
and the sagittal plane
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divid ...
, respectively.
File:Acetabular inclination of hip prosthesis.jpg, Acetabular inclination.[ This parameter is calculated on an anteroposterior radiograph as the angle between a line through the lateral and medial margins of the acetabular cup and the ''transischial line'' which is tangential to the inferior margins of the bones.]
File:Range of acetabular inclination.png, Acetabular inclination is normally between 30 and 50°.[ A larger angle increases the risk of dislocation.]
File:Acetabular anteversion of hip prosthesis.jpg, Acetabular anteversion. This parameter is calculated on a lateral radiograph as the angle between the transverse plane
The transverse plane (also known as the horizontal plane, axial plane and transaxial plane) is an anatomical plane that divides the body into Anatomical terms of location#Superior and inferior, superior and inferior sections. It is perpendicula ...
and a line going through the (anterior and posterior) margins of the acetabular cup.
File:Range of acetabular anteversion.png, Acetabular anteversion is normally between 5 and 25°.[ An anteversion below or above this range increases the risk of dislocation.][ There is an ]intra-individual variability
In statistics, dispersion (also called variability, scatter, or spread) is the extent to which a distribution is stretched or squeezed. Common examples of measures of statistical dispersion are the variance, standard deviation, and interquart ...
in this method because the pelvis may be tilted in various degrees in relation to the transverse plane.[
File:Leg length discrepancy after hip replacement.jpg, ''Leg length discrepancy'' after hip replacement is calculated as the vertical distance between the middle of the minor trochanters, using the acetabular tear drops][ or the transischial line][ as references for the horizontal plane. A discrepancy of up to 1 cm is generally tolerated.][
File:Center of rotation of hip prosthesis.jpg, ''Center of rotation'': The horizontal center of rotation is calculated as the distance between the acetabular teardrop and the center of the head (or caput) of the prosthesis and/or the native femoral head on the contralateral side.][ The vertical center of rotation instead uses the transischial line for reference.][ The parameter should be equal on both sides.][
]
Alternatives and variations
Conservative management
The first line approach as an alternative to hip replacement is conservative management which involves a multimodal approach of oral medication, injections, activity modification and physical therapy
Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
. Conservative management can prevent or delay the need for hip replacement.
Preoperative care
Preoperative education is an important part of patient care. Some evidence indicates that it may slightly reduce anxiety before hip or knee replacement, with low risk of negative effects.
Hemiarthroplasty
Hemiarthroplasty is a surgical procedure that replaces one half of the joint with an artificial surface and leaves the other part unchanged. This class of procedure is most commonly performed on the hip after an intracapsular fracture of the femur neck (hip fracture
A hip fracture is a break that occurs in the upper part of the femur (thigh bone). Symptoms may include pain around the hip, particularly with movement, and shortening of the leg. Usually the person cannot walk.
They most often occur as a res ...
). The procedure is performed by removing the head of the femur and replacing it with a metal or composite prosthesis
In medicine, a prosthesis (plural: prostheses; from grc, πρόσθεσις, prósthesis, addition, application, attachment), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through trau ...
. The most commonly used prosthesis designs are the Austin Moore and Thompson prostheses. A composite
Composite or compositing may refer to:
Materials
* Composite material, a material that is made from several different substances
** Metal matrix composite, composed of metal and other parts
** Cermet, a composite of ceramic and metallic materials
...
of metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
and HDPE
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...
that forms two interphases (bipolar prosthesis) can be used. The monopolar prosthesis has not been shown to offer any advantage over bipolar designs. The procedure is recommended only for elderly/frail patients, due to their lower life expectancy and activity level. This is because over time the prosthesis tends to loosen or to erode the acetabulum
The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.
Structure
There are three bones of the ''os coxae'' (hip bone) that c ...
. Independently mobile older adults with hip fractures may benefit from a total hip replacement instead of hemiarthroplasty.
File:Bipolar hip prosthesis.jpg, Hip prosthesis for hemiarthroplasty. This example is bipolar, meaning that the head has two separate articulations.
File:X-ray of hips with a hemiarthroplasty.jpg, X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
of the hips, with a right-sided hemiarthroplasty
Hip resurfacing
Hip resurfacing
Hip resurfacing has been developed as a surgical alternative to total hip replacement (THR). The procedure consists of placing a cap (usually made of cobalt-chrome metal), which is hollow and shaped like a mushroom, over the head of the femur whi ...
is an alternative to hip replacement surgery. It has been used in Europe since 1998 and became a common procedure. Health-related quality of life measures are markedly improved and patient satisfaction is favorable after hip resurfacing arthroplasty.
The minimally invasive hip resurfacing
Minimally invasive hip resurfacing (MIS) is a total or partial hip surgery that can be carried out through an incision of less than 10 cm (4 inches) without imparting great forces on the anatomy or compromising component positioning.Comis Or ...
procedure is a further refinement to hip resurfacing.
Viscosupplementation
Viscosupplementation is the injection of artificial lubricants into the joint. Use of these medications in the hip is off label. The cost of treatment is typically not covered by health insurance.
Some authorities claim that the future of osteoarthritis treatment is bioengineering
Biological engineering or
bioengineering is the application of principles of biology and the tools of engineering to create usable, tangible, economically-viable products. Biological engineering employs knowledge and expertise from a number o ...
, targeting the growth and/or repair of the damaged, arthritic joint. Centeno et al. reported on the partial regeneration of an arthritic human hip joint using mesenchymal stem cell
In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type o ...
s. It is yet to be shown that this result will apply to a large group of patients and result in significant benefits. The FDA stated that this procedure does not conform to regulations, but Centeno claims that it is exempt from FDA regulation. It has not been shown in controlled clinical trials to be effective.
Prevalence and cost
Total hip replacement incidence varies in developed countries between 30 (Romania) and 290 (Germany) procedures per 100,000 population per year. Approximately 0.8% of Americans have undergone the procedure.
According to the International Federation of Healthcare Plans, the average cost of a total hip replacement in 2012 was $40,364 in the United States, $11,889 in the United Kingdom, $10,987 in France, $9,574 in Switzerland, and $7,731 in Spain. In the United States, the average cost of a total hip replacement varies widely by geographic region, ranging from $11,327 (Birmingham, Alabama) to $73,927 (Boston, Massachusetts).
History
The earliest recorded attempts at hip replacement were carried out in Germany in 1891 by Themistocles Gluck
Themistocles Gluck (30 November 1853 in Iaşi, Moldavia – 25 April 1942 in Berlin) was a German physician and surgeon. He first invented endoprostheses from ivory in 1890 at Berlin, when he performed the first documented total wrist Arthroplas ...
(1853–1942), who used ivory to replace the femoral head
The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur). It is supported by the femoral neck.
Structure
The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a l ...
(the ball on the femur), attaching it with nickel-plated screws. Subsequently, he used a cement made from plaster of Paris, powdered pumice and glue.
Molded-glass implants were introduced in the 1920s by Smith-Peterson in the USA. Although these showed good bio-compatibility, they were mechanically fragile so he started experiments with metallic prostheses in the 1930s. In 1938, Philip Wiles of Middlesex General Hospital, UK carried out a total hip replacement using a stainless-steel prosthesis attached by bolts. In 1940, Dr. Austin T. Moore (1899–1963) at Columbia Hospital in Columbia, South Carolina
Columbia is the capital of the U.S. state of South Carolina. With a population of 136,632 at the 2020 census, it is the second-largest city in South Carolina. The city serves as the county seat of Richland County, and a portion of the city ...
performed a hip replacement using a prototype prosthesis made of the cobalt-chrome alloy Vitallium; it was inserted into the medullary canal and "fenestrated" to promote bone regrowth. A commercial version known as the "Austin Moore Prosthesis" was introduced in 1952; it is still in use today, typically for femoral neck fractures in the elderly. Following the lead of Wiles, several UK general hospitals including Norwich
Norwich () is a cathedral city and district of Norfolk, England, of which it is the county town. Norwich is by the River Wensum, about north-east of London, north of Ipswich and east of Peterborough. As the seat of the See of Norwich, with ...
, Wrightington
Wrightington is a civil parish in West Lancashire, England, with an area of 3,915½ acres. The surface is hilly, rising to over 400 ft. at Harrock on the border of Parbold, and then falling to the north, northeast and southeast. On the sou ...
, Stanmore
Stanmore is part of the London Borough of Harrow in London. It is centred northwest of Charing Cross, lies on the outskirts of the London urban area and includes Stanmore Hill, one of the highest points of London, at high. The district, which ...
, Redhill and Exeter
Exeter () is a city in Devon, South West England. It is situated on the River Exe, approximately northeast of Plymouth and southwest of Bristol.
In Roman Britain, Exeter was established as the base of Legio II Augusta under the personal comm ...
developed metal-based prostheses during the 1950s and 1960s.
Metal/Acrylic prosthesis were tried in the 1950s but were found to be susceptible to wear. In the 1960s, John Charnley
Sir John Charnley, (29 August 1911 – 5 August 1982) was an English orthopaedic surgeon. He pioneered the hip replacement operation, which is now one of the most common operations both in the UK and elsewhere in the world, and created the ...
at Wrightington General Hospital combined a metal prosthesis with a PTFE
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...
acetabular cup before settling on a metal/polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...
design. Ceramic bearings were developed in the late 1970s.
The means of attachment also has diversified. Early prostheses were attached by screws (e.g. Gluck, Wiles) with later developments using dental or bone cements (e.g. Charnley, Thompson) or cementless systems which relied on bone regrowth (Austin-Moore, Ring). The choice of alloy, bearing material, attachment and detailed geometry has led to the wide variety of prosthesis designs available today.
The London Science Museum
A science museum is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in mu ...
has a collection of hip prostheses which reflect developments in the US, UK and elsewhere. These show the use of different materials and different designs for different circumstances (e.g. cemented and uncemented arthroplasty.) Some are on display in the museum's "Medicine: The Wellcome Galleries".
The items include:
* Prosthesis from 1960: The "Gosset-style" prosthesis was first introduced in 1949, although the specific example was made by Lusterlite Ltd of Leeds
Leeds () is a city and the administrative centre of the City of Leeds district in West Yorkshire, England. It is built around the River Aire and is in the eastern foothills of the Pennines. It is also the third-largest settlement (by populati ...
in 1960. It has a perspex "ball" and simple rod-like shaft made of nickel-plated stainless-steel.
* Examples of prostheses from 1970 to 1985: Examples provided by Ipswich
Ipswich () is a port town and borough in Suffolk, England, of which it is the county town. The town is located in East Anglia about away from the mouth of the River Orwell and the North Sea. Ipswich is both on the Great Eastern Main Line r ...
Hospital, UK are made of Vitallium
Vitallium is an alloy of 65% cobalt, 30% chromium, 5% molybdenum, and other substances. The alloy is used in dentistry and artificial joints, because of its resistance to corrosion. It is also used for components of turbochargers because of its ...
(Co/Cr alloy) with curved standard or slender femoral stems. One example has a studded cup.
* Examples of prostheses from the 1990s: Examples, some of which were developed at the Redhill Group of Hospitals and Dorking Hospital, include a ringed titanium hip prosthesis with a screw stem and porous cup, a modular hip prosthesis with a textured femoral stem to aid bone grafting (material unspecified), two Thompson-type prostheses made of Vitallium
Vitallium is an alloy of 65% cobalt, 30% chromium, 5% molybdenum, and other substances. The alloy is used in dentistry and artificial joints, because of its resistance to corrosion. It is also used for components of turbochargers because of its ...
alloy and an Austin Moore type prosthesis (material unspecified), with a porous metal femoral stem.
* Example of acetabular cup prosthesis from 1998: Example of a prosthetic socket, from Sulzer Orthopedics Inc., is the Inter-Op Hemispherical Shell. This is made from materials not recognised by the human body, so the body's immune system does not attack and reject the joint.
* Examples of prostheses from 2006: Examples made by Smith & Nephew Orthopedics include an "Anthology" titanium prosthesis, which has a flat-tapered stem placed in the thigh bone, and an "Echelon" (cobalt-chrome prosthesis for both cementless and cemented arthroplasty
Arthroplasty (literally " e-orming of joint") is an orthopedic surgical procedure where the articular surface of a musculoskeletal joint is replaced, remodeled, or realigned by osteotomy or some other procedure. It is an elective procedure that i ...
. Both have porous coating to promote bone adhesion.
The Science Museum's collection also includes specialised surgical tools for hip operations:
* Instrument sets made by Downs Ltd for the City Hospital, Nottingham University Hospitals UK. Tools include head punches, reamers, drills and rasps.
* Prototype oscillating bone saws made by Kenneth Dobbie in the 1960s. Dobbie was electrical engineer at the Royal National Orthopaedic Hospital
The Royal National Orthopaedic Hospital (RNOH) is a specialist orthopaedic hospital located in the London Borough of Harrow, United Kingdom, and a part of Royal National Orthopaedic Hospital NHS Trust. It provides the most comprehensive range of ...
, Stanmore, UK. He worked closely with the hip surgeon Sir John Charnley
Sir John Charnley, (29 August 1911 – 5 August 1982) was an English Orthopedic surgery, orthopaedic surgeon. He pioneered the hip replacement operation, which is now one of the most common operations both in the UK and elsewhere in the wo ...
to develop the saws eventually leading to a commercial product made by De Soutter Brothers Ltd.
Other animals
See also
* 2010 DePuy Hip Recall The 2010 DePuy Hip Replacement Recall was instituted when DePuy Orthopaedics, Inc., a division of Johnson and Johnson, recalled its ASR XL Acetabular metal-on-metal hip replacement system on August 24, 2010.
Background
The recall came after data f ...
* Abductor wedge
* Femoroacetabular impingement
Femoroacetabular impingement (FAI) is a condition involving one or more anatomical abnormalities of the hip joint, which is a ball and socket joint. It is a common cause of hip pain and discomfort in young and middle-aged adults. It occurs when th ...
* Gruen zone
After hip replacement, hip prosthesis zones are regions in the interface between prosthesis material and the surrounding bone. These are used as reference regions when describing for example complications including hip prosthesis loosening on med ...
* Hip examination
In medicine, physiotherapy, chiropractic, and osteopathy the hip examination, or hip exam, is undertaken when a patient has a complaint of hip pain and/or signs and/or symptoms suggestive of hip joint pathology. It is a physical examination mane ...
References
External links
Edheads Virtual Hip Surgery + Surgery Photos
{{DEFAULTSORT:Hip Replacement
Implants (medicine)
Orthopedic surgical procedures
Pelvis
Prosthetics
Orthopedic implants