INTRODUCTION — Total hip arthroplasty (THA) is one of the most successful orthopedic procedures performed today. For patients with hip pain due to a variety of conditions, THA can relieve pain, restore function, and improve quality of life. Sir John Charnley, a British orthopedic surgeon, developed the fundamental principles of the artificial hip and is credited as the father of THA. He designed a hip prosthesis in the mid- to late 1960s. Approximately 500,000 THAs are performed each year in the United States alone [1,2].
The evaluation and management of patients undergoing THA, as well as the conduct of the procedure, are reviewed here. The complications of THA are presented in detail separately. (See "Complications of total hip arthroplasty".)
Indications — Total hip arthroplasty (THA) is indicated for patients who have failed conservative or previous surgical treatment options for a deteriorated hip joint and who continue to have persistent, debilitating pain and a significant decrease in the activities of daily living. Patients with significant deformity and limitation of motion may also be candidates if the disability that results is considerable, even in the absence of pain. The decision to proceed with THA is made with an understanding of the potential benefits and risks. A thorough understanding of the procedure and the anticipated outcome is an important part of the decision-making process.
The normal hip functions as a "ball-and-socket" joint. The femoral head (ball) articulates with the acetabulum (socket), allowing a smooth range of motion in multiple planes. Any condition that affects either of these structures can lead to deterioration of the joint. This, in turn, can lead to deformity, pain, and loss of function. The most common condition affecting the hip in this way is osteoarthritis. Other conditions that may affect the hip adversely include inflammatory arthritides (eg, rheumatoid arthritis, psoriatic arthritis, spondyloarthropathies), femoroacetabular impingement syndrome, developmental hip dysplasia, childhood hip disorders (eg, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis), trauma, neoplasms, and osteonecrosis.
Contraindications — THA should not be undertaken in a number of clinical settings, including:
●Active infection (local or systemic)
●Preexisting significant medical problems (eg, recent myocardial infarction, unstable angina, heart failure, severe anemia)
●Permanent or irreversible muscle weakness in the absence of pain
Active infection is perhaps the most significant contraindication to THA. An infected THA can be a devastating and costly complication. Infection and other complications of THA are discussed in detail elsewhere. (See "Complications of total hip arthroplasty".)
Relative contraindications include paraplegia, inability to ambulate that is not related to the hip disorder per se, absence of hip abductor muscle function, progressive neurologic deficit, a neuropathic (Charcot) joint , and people with severe obesity.
Alternatives — THA is typically an elective procedure. Thus, a conservative approach aimed at treating the underlying disease should be tried before THA. For patients with osteoarthritis, this usually includes nonoperative treatment measures, such as weight reduction, physical therapy, nonsteroidal antiinflammatory drugs (NSAIDs), assistive devices (eg, a cane), and intraarticular glucocorticoid injections. For patients with inflammatory arthritis of the hip (eg, rheumatoid arthritis or spondyloarthropathy), THA is offered to address the symptoms of advanced structural disease and not those of the underlying inflammatory disorder, which is treated medically.
In selected cases, the suitability of surgical procedures other than THA such as hemiarthroplasty, hip resurfacing, arthrodesis, and hip osteotomy may be discussed with the patient. (See "Overview of surgical therapy of knee and hip osteoarthritis", section on 'Alternatives to total hip arthroplasty'.)
PREOPERATIVE EVALUATION — A careful preoperative evaluation is essential to confirm hip pathology as the source of symptoms and disability and ensure the appropriateness of surgery, as well as to assist with surgical planning. General issues in preoperative medical consultation and management are presented elsewhere. (See "Preoperative medical evaluation of the healthy adult patient".)
History and physical examination — Most patients with deterioration of the hip joint present with pain. This is typically localized to the anterior hip or groin. Pain may also be present in the posterior buttock and trochanteric region and can radiate to the thigh or knee. Pain typically occurs with activity but can also be present at rest. The pain is often exacerbated by weightbearing and may be worse with initial movement. Patients frequently describe "stiffness" or "tightness" of the hip, and loss of motion is often noted. Disruption of sleep and difficulty walking, putting on shoes and socks, going up and down stairs, or getting into and out of a car are common complaints. The patient may also need an assistive device (eg, cane).
A thorough musculoskeletal examination should be performed in every candidate for total hip arthroplasty (THA). A more detailed description of hip anatomy, pain patterns, differential diagnosis, and physical examination of the hip, including special maneuvers, is available elsewhere. (See "Approach to the adult with unspecified hip pain".)
Particular attention to the spine, pelvis, and knees is also essential to rule out radicular pathology, since hip pain may be the indirect result of radicular pathology, as well as other concomitant diseases.
Prior to surgery, the following evaluations of the lower extremities are essential:
●Inspection – Gait, previous incisions, abnormal swelling of hip or limb, abrasions, discolorations, and cutaneous infections should be evaluated by inspection. Gait assessment should include an evaluation of any limp, use of assistive devices, and/or limb length discrepancy. The presence or absence of a Trendelenburg gait should be noted. Any evidence of a "minor" infection (eg, infected ingrown toenail) may require a delay in surgery until the infection has completely resolved.
●Palpation – Anterior superior iliac spines, iliac crest, greater trochanter, posterior superior iliac spines, ischial tuberosity, and sacroiliac joint should be evaluated by palpation. Palpation can help rule out nonarticular causes of "hip pain." For example, lateral hip pain localized over the greater trochanter is usually not an indicator of hip joint pathology but may actually represent greater trochanteric bursitis or greater trochanteric pain syndrome (from inflammation or tendinopathy of the gluteus medius and minimus tendons). (See "Greater trochanteric pain syndrome (formerly trochanteric bursitis)", section on 'Clinical presentation'.)
●Range of motion – Hip flexion/extension, abduction/adduction, and internal/external rotation should be recorded. Contractures should be noted. Limitation of motion often develops as hip pathology progresses. Joint surface incongruity, muscle spasms, soft tissue contracture, and/or mechanical block (eg, osteophytes or loose bodies) may all contribute to decreased motion.
●Muscle testing – Motor strength and tone of the hip flexors, extensors, abductors, and adductors should be evaluated and documented. In addition, muscle strength and tone of the distal limb should also be tested.
●Nerve and vascular status – Preoperatively, it is imperative to evaluate and document nerve and vascular status. Sciatic and peroneal nerve function testing, assessment of arterial pulses, and a sensory examination should be performed and documented for both limbs. In addition, venous insufficiency should be noted. Severe vascular disease should be evaluated by a vascular surgeon prior to proceeding with surgery.
•Leg length measurement – As part of preoperative planning, leg lengths must be evaluated. There are two types of leg length discrepancy:
-"Apparent" leg length discrepancy is the result of compensation in response to pathology or contracture rather than an actual difference in leg lengths (eg, presence of scoliosis or pelvic obliquity).
-True leg length discrepancy is the result of an anatomic or structural change in the lower limb (eg, tibia fracture). Typically, a deteriorated hip joint will cause a decrease in true leg length.
To measure leg length, the patient should lie supine with the lower limbs in comparable positions with the legs slightly apart and parallel. A tape measure can be used to record the length between the anterior superior iliac spine and the medial malleolus for each limb. Another useful method of identifying a true leg length discrepancy is by using blocks of varying height. The patient is asked to stand, and blocks of varying height are placed under the shorter limb. When the iliac crests are at the same level, the block height represents a good approximation of the true leg length discrepancy.
•Trendelenburg sign – This test assesses the strength and function of the hip abductors. The sign is elicited by asking the patient to stand on the involved leg. Normally, the pelvis on the opposite side rises. However, if the pelvis on the opposite side drops, this test is positive. A positive test indicates that the hip abductors of the involved limb are weak or are relatively inhibited.
•Straight leg raise – When this test is performed against resistance, groin pain is typically elicited if significant hip pathology is present (eg, Stinchfield test). In addition, when this test is performed passively by the examiner, radiating pain from the back or posterior hip into the lower leg suggests a radicular pathology.
Medical risk assessment — The patient undergoing THA must be able to tolerate anesthesia, associated operative stress, and perioperative blood loss, as well as the rehabilitation process involved following THA. Since many patients who undergo THA are older, specific attention should be paid to the patient's comorbid medical problems and symptoms that may reflect underlying comorbidities that need to be considered prior to undergoing THA.
A more detailed discussion of the medical risk assessment prior to THA, which is similar to that for total knee arthroplasty (TKA), can be found elsewhere (see "Total knee arthroplasty", section on 'Medical risk assessment'). A more general preoperative medical evaluation is also reviewed separately. (See "Preoperative medical evaluation of the healthy adult patient" and "Evaluation of cardiac risk prior to noncardiac surgery" and "Evaluation of perioperative pulmonary risk" and "Preoperative evaluation and perioperative management of patients with rheumatic diseases".)
The overall success and longevity of the implant may depend on several patient-related factors that are associated with increased wear, including younger age, high activity level, and obesity . (See 'Longevity of implant' below.)
Laboratory studies — Baseline laboratory tests should include a complete blood count (CBC), prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), blood type/screen, and basic chemistries. An electrocardiogram (ECG) is often performed. Urinalysis should be obtained in patient with urinary symptoms. Any identified urinary tract infection (>100,000 colony-forming units [CFU]) should be treated with antibiotics prior to surgery . Other laboratory tests can be ordered, as needed, to assess abnormalities found during the preoperative examination.
Imaging studies — Plain radiographs of the hip and pelvis confirm the diagnosis and help with preoperative planning for THA. Preoperative films should include a weightbearing anteroposterior (AP) pelvis, as well as AP and lateral views of the affected hip. Care should be taken to ensure that the entire proximal femur is visualized so that any deformity can be identified. In addition to plain radiographs, magnetic resonance imaging (MRI) may be necessary to evaluate certain hip disorders such as osteonecrosis. If significant lumbar disease or history of lumbar spine surgery is noted, separate lumbar spine films may be obtained for further evaluation. Standing and sitting lateral films from the first lumbar vertebra to the pelvis may help in evaluation of the spine-pelvis-hip relationship. A discussion of imaging techniques and modalities for evaluation of hip pain is presented separately. (See "Approach to the adult with unspecified hip pain".)
Antimicrobial prophylaxis — All patients undergoing total hip arthroplasty (THA) should receive prophylactic antibiotics (table 1). Prophylactic regimens are discussed in detail elsewhere. (See "Prevention of prosthetic joint and other types of orthopedic hardware infection", section on 'During hardware placement'.)
Thromboprophylaxis — Thromboprophylaxis (pharmacologic, mechanical) is indicated for patients undergoing THA because they are at moderate-to-high risk for thromboembolism. A discussion on the incidence of venous thromboembolism after THA can be found elsewhere. (See "Complications of total hip arthroplasty", section on 'Venous thromboembolism'.)
Our practice is generally consistent with guidelines from the American College of Chest Physicians (ACCP), the American Society of Hematology (ASH), and the American Academy of Orthopaedic Surgeons (AAOS). The approach to prevent thromboembolic disease in patients undergoing THA is discussed in detail separately. (See "Prevention of venous thromboembolism in adults undergoing hip fracture repair or hip or knee replacement".)
Anesthetic considerations — THA may be performed with general anesthesia, regional anesthesia, or neuraxial anesthesia (ie, spinal, epidural, or combined spinal epidural). The choice of anesthetic technique is based on patient comorbidities and patient choice. General anesthesia is used for patients with contraindications to neuraxial anesthesia and for some patients with potential difficulty with airway management. In practice, many patients receive some elements of both types of anesthesia. During neuraxial anesthesia, most patients receive heavy sedation, and patients who receive general anesthesia for THA may also have epidural analgesia for postoperative pain control.
Comparisons of general and neuraxial anesthesia for THA show some differences for some, but not all, outcomes. In one meta-analysis that includes patients undergoing total hip or knee arthroplasty, length of hospital stay was reduced for those undergoing neuraxial anesthesia (weighted mean difference -0.4 days [-0.76 to -0.03]) . However, there were no significant differences in mortality, chest infection, or thromboembolism. Blood loss and transfusion were not evaluated because of the low quality of studies.
For uncomplicated primary THA, single injection spinal anesthesia is a commonly used technique. Epidural or combined spinal-epidural are used for procedures that are expected to last more than approximately two hours and if postoperative epidural analgesia is planned. Any plans for ongoing use of antithrombotic therapies (antiplatelet agents, anticoagulants) should be discussed with the surgeon before finalizing plans for regional anesthesia techniques, either used intraoperatively or postoperatively. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication".)
Perioperative pain control — A multimodal strategy for control of pain control after THA may include regional anesthesia, acetaminophen, and nonsteroidal antiinflammatory drugs (NSAIDs), which are often used to reduce the need for opioids. (See "Approach to the management of acute pain in adults".)
●Lumbar epidural analgesia – Postoperative continuous epidural analgesia can be used if epidural or combined spinal-epidural anesthesia is used for surgery. (See "Approach to the management of acute pain in adults", section on 'Regional anesthesia techniques'.)
●Peripheral nerve block – Sensory innervation of the hip joint includes femoral, sciatic, and obturator nerves. Therefore, no single nerve block can be used to provide complete analgesia after THA. Lumbar plexus block may provide adequate postoperative analgesia after THA but can be technically challenging and carries risks including neuraxial spread of local anesthetic, neuraxial hematoma, and retroperitoneal hematoma. It can be considered as part of a multimodal pain control strategy for patients with chronic pain, opioid tolerance, or sensitivity to opioids. (See "Lower extremity nerve blocks: Techniques", section on 'Lumbar plexus (psoas compartment) block'.)
TOTAL HIP ARTHROPLASTY PROCEDURE
Total hip arthroplasty implant design — All total hip arthroplasties (THAs) consist of a femoral component, an acetabular component, and a bearing surface. Most systems are modular with a separate femoral stem, femoral head, acetabular liner, and acetabular shell. This modularity gives the operating surgeon tremendous flexibility in dealing with any intraoperative situation or anatomic variation. There are a number of femoral and acetabular implants available for use in THA. The choices reflect different philosophies regarding the type of fixation, design features, and materials.
Fixation of the prosthetic components to host bone can be achieved with one of two techniques. The more common approach in the United States achieves fixation without the use of cement and relies on bony ingrowth into or onto the porous implant surface that has been either "press-fit" or "interference-fit" into the surrounding bone. Alternatively, methylmethacrylate cement can be used to fix the femoral and/or acetabular component in patients with poor bone quality.
Surgeons may select antibiotic-loaded cement in total hip arthroplasty (or hip hemiarthroplasty), either routinely or selectively in patients at high risk for infection. The optimal dosing and effectiveness have not been fully assessed. Commercially available antibiotic-loaded cement usually comes premixed with low-dose antibiotics (typically less than 1 gram per 40 gram batch of cement). Surgeons may choose to place higher doses of antibiotics within the cement (greater than commercially available) for high-risk patients, but this must be weighed against the potential that high-dose antibiotics can weaken the cement and predispose to failure. Moreover, in a randomized trial, high-dose dual antibiotic-loaded cement did not reduce the incidence of deep surgical site infection after hip hemiarthroplasty compared with single antibiotic-loaded cement . (See "Prevention of prosthetic joint and other types of orthopedic hardware infection", section on 'Local antibiotic delivery'.)
Acetabular component — While there are many options for acetabular components in primary THA, the majority of acetabular components inserted today are cementless, porous, and modular. Typically, a hemispheric porous metal shell is inserted into the acetabulum, and a modular liner is then placed within the shell. The acetabular liner, typically made of highly crosslinked polyethylene, is designed to articulate with a highly polished femoral head (ball). The porous surface of the implant varies from manufacturer to manufacturer and may have a surface coating (such as hydroxyapatite) that promotes bony ingrowth or ongrowth. Many designs allow for the insertion of screws for supplementary fixation of the shell.
The alternative to a cementless acetabular component is an acetabular component fixed to the acetabulum with cement. This type of acetabular implant has fallen out of favor in the United States due to studies showing a higher overall loosening rate than with uncemented implants. However, some surgeons advocate the use of an all-polyethylene cemented acetabular implant for older patients with poor bone quality .
Bearing surface — In the past, the standard bearing surface consisted of a metallic (cobalt-chromium) femoral head, which articulated with a smooth, high-density polyethylene acetabular liner. Due to osteolysis (bone loss and destruction) caused by wear and resultant particle debris, this combination is used less commonly. The most widely used combination is a ceramic femoral head with an acetabular liner made of highly crosslinked polyethylene. Laboratory results show superior wear performance of highly crosslinked polyethylene compared with conventional high-density polyethylene [9,10]. Furthermore, clinical results have shown superior longevity of highly crosslinked polyethylene compared with conventional high-density polyethylene in vivo [11-13]. Ceramic femoral heads avoid the risk of taper corrosion that can occur with a metal head on metal trunnion (mixed-metal taper junction).
Other bearing surfaces used in the hip include ceramic-on-ceramic and metal-on-metal. While these have both demonstrated reduced wear as compared with standard metal-on-polyethylene, other potential complications have limited their widespread use. Ceramic-on-ceramic bearing surfaces have rarely shown catastrophic breakages as well as minor chips and cracks. With newer ceramic technology, this occurs much less frequently. Another complication of a ceramic-on-ceramic bearing surface is an audible squeak.
Metal-on-metal bearing surfaces were introduced because they were thought to offer advantages over other materials, including less wear and lower risk of dislocation because of the ability to use larger head ball sizes. However, subsequent studies showed that metal-on-metal THA did not confer a clinical advantage over other bearing surfaces and resulted in higher rates of revision [14-18]. The lack of evidence as a superior bearing surface along with adverse local tissue reactions have limited the use of metal-on-metal bearing surfaces in conventional THA. This is in contrast to metal-on-metal resurfacing procedures, where the results in select patient cohorts have been equal to or better than conventional THA in terms of implant survival, patient mortality, and function [19-21]. However, adverse local tissue reactions have been described for metal-on-metal resurfacings as well. It should be noted that metal-on-metal bearing surfaces are contraindicated in patients with compromised kidney function as well as women of childbearing age due to unknown effects of metal ions on the unborn fetus. Complications from metal-on-metal wear is discussed separately. (See "Complications of total hip arthroplasty", section on 'Sequelae from metal-on-metal wear debris'.)
Femoral component — Femoral components can be classified as either cementless or cemented. A cementless femoral component is the implant of choice for younger patients and any patient with good bone stock (particularly those with thick femoral cortices and with smaller diameter femoral canals). However, in older patients and those with osteoporosis, it may be more difficult to get good initial stability with a cementless component and there is a higher risk of periprosthetic femoral fracture. In addition, a larger (and necessarily stiffer) implant would be required. Therefore, a cemented implant is an appropriate choice in the older, low-demand patient with poor bone stock (thin cortices and larger canal diameter).
Cementless implants are typically porous-coated to increase surface area for bone ingrowth. In addition, the roughened surface helps to achieve initial stability of the implant, which is critical for the long-term success of the implant. The porous coating may be limited to the proximal portion of the femoral implant or may extend over the entire length of the implant. This varies depending upon the philosophy of the design. Proximally porous coated implants rely on the metaphysis or metadiaphyseal junction for fixation and stability. Extensively porous-coated implants rely more on diaphyseal fixation. Cementless implant designs use a circumferential porous coating, which has been shown to help prevent access of wear particles from the articulating surface down along the implant-bone interface.
The use of bone cement during arthroplasty can rarely cause bone cement implantation syndrome (BCIS), which is a poorly understood condition that can cause hypoxia and hypotension, and may result in cardiac arrest. Measures to prevent BCIS include pulse lavage of the femoral canal, slow introduction of the stem, providing a vent hole in the bone for long-stem component insertion, and minimal pressurization of cement. (See "Complications of total hip arthroplasty".)
Femoral head — The femoral head in any THA must match the acetabular bearing surface. Almost all THAs performed today utilize a highly polished ceramic or cobalt chrome femoral head. Due to increased awareness and prevalence of trunnionosis (wear at the femoral head-neck interface), there has been a shift towards greater use of ceramic as the femoral head material of choice. Different diameters are available ranging from 22 mm up to 40 mm (or greater). The key considerations regarding head size are range of motion, stability, and propensity for wear. In general, increasing head size is correlated with increased range of motion and decreased dislocation rate but also with increased volumetric wear and generation of particle debris. Therefore, a compromise must be made. The introductions of more durable acetabular liners (eg, highly crosslinked polyethylene) and alternative bearing surfaces have led most surgeons towards the use of a larger head size than the prior standard of 28 mm typically used in primary THA. The larger prosthetic head allows for improved range of motion and decreased risk of dislocation.
Arthroplasty technique — The surgical technique for THA has evolved since it was first introduced, with a variety of surgical approaches described.
THA is carried out in a stepwise fashion (figure 1):
●The hip joint is exposed
●The femoral neck is cut (with or without dislocation of the femoral head) and the femoral head is removed
●The acetabulum is prepared and a cup is placed
●The femur is prepared and a stem is placed
●A head ball is then placed onto the stem
●The hip is reduced and the surgical wound is closed
Incision and exposure — THA can be approached using a posterolateral, direct lateral, or anterior approach. These surgical approaches all provide excellent exposure of the hip joint. A good result can be achieved through any of these approaches, and the best approach is that with which the surgeon is most comfortable. The surgical approach can impact the type and incidence of certain complications as noted the sections below .
Posterolateral approach — The posterolateral approach, also called the Kocher-Langenbeck approach, gains exposure to the hip through a posterior incision. The gluteus maximus muscle is split and the short external rotators are dissected off the posterior aspect of the hip. The joint is entered posteriorly through the capsule. The gluteus medius is left intact. This approach is usually performed with the patient in the lateral decubitus position. Variations of this approach preserve some or all of the short external rotators. A piriformis sparing approach accesses the hip joint below the piriformis tendon and a superior variation of the posterior approach accesses the hip above the short external rotators.
Because the posterolateral approach disrupts the posterior soft tissue of the hip, it has historically been associated with having a higher rate of dislocation compared with the direct lateral approach. Additional information regarding the risk of dislocation is presented separately. (See "Complications of total hip arthroplasty", section on 'Dislocation'.)
Direct lateral approach — The direct lateral approach, also called the Hardinge or modified Hardinge approach, gains exposure to the hip through a lateral incision. The anterior portion of the gluteus medius muscle is split and elevated off of the femur. This provides access to the hip through the anterior hip capsule. Typically, this approach is performed with the patient in the lateral position. However, the direct lateral approach may be performed with the patient supine or in a semilateral position. Once the THA is completed, the gluteus medius muscle insertion is repaired (by the tendon itself or with a portion of detached bone).
The direct lateral approach has a low risk of dislocation  but higher risk for postoperative limp and heterotopic ossification due to disruption of the abductor muscles [24,25]. Additional information regarding heterotopic ossification is presented separately. (See "Complications of total hip arthroplasty", section on 'Heterotopic ossification' and 'Prophylaxis for heterotopic ossification in selected patients' below.)
Anterior approach — The anterior approach, also called the Smith-Petersen or Hueter approach, gains exposure to the hip anteriorly without the need to detach any of the surrounding muscles. A space is created between the tensor fascia lata and the sartorius muscles. Access to the hip is provided through the anterior hip capsule. A variation of the anterior approach, the anterolateral approach (or Watson-Jones approach), accesses the hip through the space posterior to the tensor fascia lata. Anterior approaches are performed with the patient supine but can also be performed with the patient in a lateral position. A special operating table and the assistance of fluoroscopy are often used, but a regular operating table ("off-table") can also be used. (See "Patient positioning for surgery and anesthesia in adults".)
Complications associated with the anterior approach include intraoperative femoral fracture (due to a more challenging femoral exposure), ankle fracture (from positioning or traction issues when using a specialized operating table), and damage to the lateral femoral cutaneous nerve or femoral nerve (as branches of this nerve sit very close to the surgical field). Because the muscles around the hip are not detached during the procedure, many surgeons who use the anterior approach tell their patients that dislocation precautions are not necessary. There appears to be a lower risk of dislocation with the direct anterior approach as compared with the posterior approach, but the direct lateral approach has the lowest dislocation rate . There is also some preliminary evidence that the anterior approach is associated with a more rapid early recovery [26,27]. However, speed of recovery depends upon many variables, and a good rapid recovery can be achieved with any of the approaches with the right anesthetic regimen, patient education, and postoperative assistance.
Surgical navigation and robotic surgical assistance — Surgical navigation in THA is also being developed. Navigation involves real-time tracking of bones and surgical instruments during surgery. The potential benefits of navigation in THA are improved accuracy of implant position (particularly the acetabular component) . Similarly, a surgical robot, which can assist the surgeon in bone preparation and implant positioning, may also be used. The disadvantages of navigation systems or robotic assistance are increased operative time, the need for image acquisition preoperatively or intraoperatively, and increased expense. Navigation is used in very few hip replacements, but there is now accumulating evidence that use of this technology may help reduce the risk of dislocation and reduce the need for revision of the acetabular component [29-31].
Minimizing blood loss — THA may involve substantial intraoperative and perioperative blood loss. In one study, the estimated blood loss following THA was almost 1000 mL . This places some patients at increased risk for myocardial infarction, angina, transient ischemic attack, stroke, and seizure (especially in patients with significant systemic illness), as well as the need for blood transfusions.
Tranexamic acid, an antifibrinolytic agent, is increasingly used for joint arthroplasty to help minimize blood loss. For most patients undergoing THA, tranexamic acid is administered to decrease blood loss and the need for blood transfusion. For patients with a high baseline risk of VTE, the decision should be individualized as there is insufficient data regarding its use in this patient population.
The optimal regimen for administration of tranexamic acid is still uncertain, since various doses and routes of administration (ie, oral, topical, and intravenous) are available [33-42]. A common regimen is to give 1 gram of tranexamic acid intravenously before incision and 1 gram of tranexamic acid intravenously during closure. Tranexamic acid can also be given in the postoperative period as needed. This practice is consistent with the guideline regarding tranexamic acid that has been published and endorsed by the American Association of Hip and Knee Surgeons, American Society of Regional Anesthesia and Pain Medicine, American Academy of Orthopaedic Surgeons, Hip Society, and Knee Society .
The efficacy and safety of tranexamic acid has been evaluated in randomized trials [44-46] and meta-analyses [47-50]. In one of the largest meta-analyses, the administration of either topical or intravenous tranexamic acid during THA was associated with less total blood loss, lower transfusion rates, and shorter hospitalization duration compared with controls . Although there was no increased risk of deep vein thrombosis, the outcome of pulmonary embolism or other vascular complications was not included in the analysis.
A general discussion of preoperative and intraoperative blood conservation techniques is presented separately. (See "Perioperative blood management: Strategies to minimize transfusions", section on 'Preoperative strategies' and "Perioperative blood management: Strategies to minimize transfusions", section on 'Intraoperative strategies'.)
Managing limb length discrepancy — As noted previously, a deteriorated hip joint may cause a decrease in leg length. In most patients, it is desired to achieve equal leg lengths postoperatively. Sometimes, however, surgeons may desire to lengthen a leg beyond the pre-arthritic length to improve stability of the hip. Tensioning the soft tissues around the hip (hip capsule and abductors) may help reduce the risk of dislocation. Ultimately, hip stability is more important than leg length discrepancy. Most surgeons would accept a small leg length inequality in exchange for a hip that is more stable and less likely to dislocate.
Intraoperatively, there are many techniques to determine limb length. These range from special devices that measure from a fixed point on the pelvis to a simple comparison of intraoperative knee and heel positions. Intraoperative radiographs or fluoroscopy may also be very useful. Some method is required for measuring limb length, and redundancy is desirable.
POSTOPERATIVE CARE AND FOLLOW-UP — The hospital length of stay following total hip arthroplasty (THA) is typically one to three days. However, there are a growing number of surgeons who are now safely performing this procedure as outpatient [51-53].
Postoperative management includes pain management, prophylaxis against venous thromboembolism, appropriate attention to medical comorbidities, and physical therapy. (See 'Perioperative care' above.)
Rehabilitation — Many patients can be discharged home after surgery, but some may require a temporary inpatient rehabilitation or nursing facility stay. Mobilization and physical therapy are initiated as soon as possible to facilitate recovery of function and to help prevent deep vein thrombosis (DVT). Rapid recovery protocols are becoming more widespread. Exercises to restore normal hip motion and strength and a gradual return to everyday activities are initiated in the hospital and continued upon discharge . This may involve 20 to 30 minutes of exercises two or three times daily during early recovery. Typically, weightbearing as tolerated is allowed, and an assistive device is used to help with balance and stability. Walking aids are weaned as strength, balance, and comfort improve. Depending on the surgical approach and surgeon's protocol, some patients may need to follow certain dislocation precautions. As an example, patients given posterior hip dislocation precautions may be asked to avoid low chairs, not to bend their hip beyond 90 degrees, and to avoid crossing their legs. Some surgeons may also recommend formal outpatient therapy, but this is often individualized based on the surgeon's preferences and the patient's needs .
Time to full recovery varies widely, but patients are typically doing quite well with minimal pain by three months postoperatively. There may be further improvement noted even up to one year following surgery.
Follow-up and activity level — Follow-up visits with the surgeon are scheduled at routine intervals, but may vary from surgeon to surgeon. Most patients may resume regular, non-impact activities such as walking, stair-climbing, swimming, golf, light tennis, and biking. These activities can be resumed once comfort and strength allows. High-impact activities such as manual labor, heavy lifting, and high-intensity sports (eg, running, jogging) should be avoided. Other activities such as yoga and Pilates may be allowed if care is taken to avoid extremes in range of motion to avoid dislocation. Long-term follow-up is recommended to evaluate for wear of the bearing surface or other implant-related issues.
Prophylaxis for heterotopic ossification in selected patients — For patients at high risk of heterotopic ossification (HO), we suggest administering prophylactic nonsteroidal antiinflammatory drugs (NSAIDs). External beam radiation (typically given as a single dose perioperatively) is a reasonable alternative for patients who cannot tolerate NSAIDs or for whom NSAIDs are contraindicated. However, the decision for which method of prophylaxis to use is typically surgeon dependent. Both methods have been shown to decrease the incidence of HO in high-risk patients. A previous history of HO is one of the strongest risk factors for HO after THA . Other factors placing patients at higher risk for HO include male sex, cemented implant, bilateral surgery, ankylosing spondylitis, and the direct lateral surgical approach [57,58]. A detailed description of the incidence and presenting symptoms of HO after THA is presented separately. (See "Complications of total hip arthroplasty".)
Indomethacin is the most commonly used NSAID for HO prophylaxis, although other NSAIDs have demonstrated effectiveness . The usual dose of indomethacin is 75 to 100 mg/day. It is typically initiated within 24 to 48 hours for surgery, and then continued for 7 to 14 days postoperatively. The efficacy for NSAIDs in reducing the incidence of postoperative HO is supported by randomized trials and meta-analyses [58-61]. In one of the largest meta-analyses including both randomized trials and observational studies, both selective and nonselective NSAIDs decreased the risk of forming HO after THA when compared with placebo (odds ratio [OR] -1.35, CI -1.83 to -0.86 and OR -1.58, CI -2.41 to -0.75, respectively) . Bleeding complications are more frequent in patients receiving NSAIDs in conjunction with anticoagulation for thromboembolic prophylaxis [62,63]. Careful monitoring should be implemented . Prophylactic use of a proton pump inhibitor may reduce the risk of NSAID-induced gastroduodenal damage and subsequent gastrointestinal bleeding (see "NSAIDs (including aspirin): Secondary prevention of gastroduodenal toxicity"). While indomethacin is relatively inexpensive and readily available, some patients are not able to tolerate the medication due to gastrointestinal side effects. Kidney issues (such as chronic renal insufficiency) may also make indomethacin a poor choice for prophylaxis. These patients may be more appropriate for external beam radiation.
External beam radiation has also demonstrated efficacy in preventing HO after THA . When used, it is typically administered as a single-dose regimen of 700 or 800 centigray. Radiation may be administered preoperatively (within 24 hours) or postoperatively (within 72 hours) [65-68]. Malignant transformation following this type of single-dose radiation has been reported but is very rare [69,70]. A meta-analysis that included seven randomized trials that compared radiation with NSAIDs concluded that radiotherapy is more effective, but the absolute difference in the rates of clinically significant HO were quite small, and on the order of 1 percent .
Longevity of implant — Published results of total hip arthroplasty (THA) demonstrate excellent clinical and functional results. These results vary depending upon the implant, surgical technique, the type of fixation, biomaterials, the patient's age, preoperative function, and a myriad of other factors including the hospital/clinician's surgical volume [4,72-74]. THA may be performed successfully in patients ranging from young [75-77] to older adults (over 80 years of age) . With modern bearing materials, the risk of revision is as low as 0.5 percent per year for the first 20 years where data are available. This is true for younger and older patients with only slight increases in risk in younger, more active patients . Patient satisfaction following the procedure is also typically high .
In general, over 90 percent of patients are working successfully after THA, are pain-free, and are without complication 15 years postoperatively . A large meta-analysis including data from national registries estimated that almost 60 percent of hip replacements last 25 years .
Most studies show an increased risk of early revision due to infection in patients with obesity [83,84]. This effect increases with increasing obesity, particularly with a body mass index (BMI) over 35 kg/m2. Despite the increased risk of revision in patients with obesity, the risk remains low, and such patients do have significant improvement in postoperative pain, function, and satisfaction. A study from Canada noted that patients with severe obesity can experience substantial benefit, despite a very small but statistically significant increase in the need for revision due to septic complications . Other studies have emphasized the increased risk of both superficial and deep infections and have described an increased risk of dislocation in such patients [86-88]. (See "Complications of total hip arthroplasty".)
Morbidity and mortality — Postoperative mortality after THA is overall low, with estimates citing a 30- or 90-day mortality rate of less than 1 percent [89-91]:
●Reductions in mortality rates between 1991 and 2008 were shown in an analysis of over 1.4 million Medicare beneficiaries in the United States who underwent elective primary THA during this period . The 30-day mortality decreased during this interval from 0.7 to 0.4 percent, despite a mean increase of one year in age and despite a mean increase from one to two in the number of comorbid medical conditions.
●A retrospective analysis from the United Kingdom assessed mortality within 90 days of hip replacement from 2003 to 2011, and included 409,096 primary hip replacements for osteoarthritis . During the eight years of follow-up, there was a significant decrease in mortality from 0.56 to 0.29 percent, even after adjusting for age, sex, and comorbidity.
A number of factors are associated with the risk of death after THA. As an example, mortality rates are higher in patients who have THA in the setting of hip fracture management when compared with those who have elective surgery for other indications . In addition, improved survival has been noted in patients administered spinal anesthesia as well as mechanical or chemical thromboprophylaxis . (See 'Perioperative care' above.)
Complications following THA include those that may occur with any major surgery, such as those related to anesthesia, blood loss, or transfusion reactions. Complications that are specific to the hip arthroplasty procedure are discussed in detail separately. (See "Complications of total hip arthroplasty".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Total hip arthroplasty".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Deciding to have a hip replacement (The Basics)")
●Beyond the Basics topics (see "Patient education: Total hip replacement (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Total hip arthroplasty (THA), also known as total hip replacement, consists of resection of the diseased articular surfaces of the hip, followed by replacement with prosthetic hip components. For the properly selected patient, the procedure results in significant pain relief, as well as improved function and quality of life. In spite of the potential benefits of THA, it is typically an elective procedure and should only be considered after a thorough discussion of the risks, benefits, and alternatives. (See 'Introduction' above and 'Preoperative considerations' above.)
●The most common indication for THA is for the relief of pain associated with osteoarthritis of the hip in patients who have failed nonoperative treatments. Other conditions that cause pain and loss of function that may result in the need for THA include inflammatory arthritides (eg, rheumatoid arthritis, psoriatic arthritis, spondyloarthropathies), femoroacetabular impingement syndrome, developmental hip dysplasia, childhood hip disorders (eg, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis), trauma, neoplasms, and osteonecrosis. (See 'Indications' above.)
●Active infection is perhaps the most significant contraindication to THA. Other contraindications include preexisting or significant medical problems (eg, recent myocardial infarction, unstable angina, heart failure, severe anemia), skeletal immaturity, quadriplegia, or permanent or irreversible muscle weakness in the absence of pain. Relative contraindications include paraplegia, inability to ambulate that is not related to the hip disorder per se, absence of hip abductor muscle function, progressive neurologic deficit, a neuropathic (Charcot) joint, and patents with severe obesity. (See 'Contraindications' above.)
●A careful preoperative evaluation must be performed to confirm hip pathology as the source of symptoms and disability and ensure the appropriateness of surgery as well as to assist with surgical planning. The evaluation includes particular elements of the history, a physical examination, imaging and laboratory studies, a review of treatment alternatives, and discussions of the benefits and risks of the procedure. (See 'Preoperative evaluation' above.)
●Prophylactic antibiotics are given preoperatively to reduce the risk for surgical site infection and prosthetic joint infection. Postoperative thromboprophylaxis should also be administered in patients undergoing THA. Prophylactic antibiotic regimens and the approach to thromboprophylaxis in adult orthopedic surgery are discussed in detail separately. (See "Prevention of prosthetic joint and other types of orthopedic hardware infection", section on 'During hardware placement' and "Prevention of venous thromboembolism in adults undergoing hip fracture repair or hip or knee replacement".)
●THA can be performed with general anesthesia, regional anesthesia, or neuraxial (ie, spinal, epidural, or combined spinal epidural) anesthesia. The choice of anesthetic technique is based on patient comorbidities and patient choice. (See 'Anesthetic considerations' above.)
●For most patients undergoing THA, tranexamic acid is used to decrease blood loss and the need for blood transfusion. The optimal regimen for administration of tranexamic acid is still uncertain, as various doses and routes of administration (ie, oral, topical, and intravenous) are available. (See 'Minimizing blood loss' above.)
●THA is carried in stepwise fashion (figure 1). THA can be performed using a posterolateral, direct lateral, or anterior approach. (See 'Arthroplasty technique' above and 'Incision and exposure' above.)
●Total hip prostheses consist of a femoral component, an acetabular component, and a bearing surface. There are a number of femoral and acetabular implants available for use. The choices reflect different philosophies regarding the type of fixation, design features, and materials. (See 'Total hip arthroplasty implant design' above.)
●Postoperative care includes pain management and venous thromboembolism (VTE) prophylaxis, as well as appropriate physical therapy to achieve the best possible hip motion and return to full function as quickly and safely as possible. (See 'Thromboprophylaxis' above and 'Perioperative pain control' above and 'Rehabilitation' above and 'Follow-up and activity level' above.)
●For patients at high risk of heterotopic ossification (HO), we suggest administering prophylactic nonsteroidal antiinflammatory drugs (NSAIDs) (Grade 2C). External beam radiation is a reasonable alternative for patients who cannot tolerate NSAIDs or for whom NSAIDs are contraindicated. Indomethacin is the most commonly used NSAID for HO prophylaxis, although other NSAIDs are also effective. The usual dose of indomethacin is 75 to 100 mg/day and should be continued for 7 to 14 days postoperatively. Measures aimed at preventing HO should be administered before the fifth postoperative day, optimally within 24 to 48 hours. (See 'Prophylaxis for heterotopic ossification in selected patients' above.)
●THA typically results in excellent clinical and functional outcomes. Mortality following THA is overall low, with estimates citing a 30- or 90-day mortality of less than 1 percent, and is primarily related to preexisting medical comorbidities. (See 'Longevity of implant' above and 'Morbidity and mortality' above.)
●Complications specific to THA are discussed in detail separately. (See "Complications of total hip arthroplasty".)
ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Thomas Thornhill, MD, Jeffrey Katz, MD, MSc, and Bill Walter, MBBS, FRACS, PhD, who contributed to earlier versions of this topic review.
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