Total Hip Replacement: Relieving Pain and Restoring Function

Bradley Ashman, MD, David Cruikshank, MD, Michael Moran, MBBCh, FRCSC

Total hip replacement: Relieving pain and restoring function

Since the first successful modern hip arthroplasty was performed by Sir John Charnley in the 1960s, procedures and components have evolved and made joint replacement available to patients younger than 65.

ABSTRACT: Total hip replacement metal or ceramic femoral heads; and otal hip replacement is a re- is one of the most common ortho- polyethylene or ceramic acetabular markable procedure that can paedic reconstructive procedures liners. In British Columbia, the stan- Trelieve pain and restore func- performed today, with more than dard of care is a metal acetabular tion. According to the Canadian Insti- 40 000 replacements completed an- shell with a polyethylene liner and tute for Health Information, more than nually in Canada. New surgical tech- a cemented or uncemented femoral 40 000 hip replacements are complet- niques and materials have led to stem with a metal femoral head. Hip ed annually in Canada (https://secure procedures that produce profound resurfacing is an option for young .cihi.ca/estore/productFamily.htm? changes in the lives of patients and active patients, although its use locale=en&pf=PFC2945&lang=en). allow them to resume virtually all of worldwide has declined dramatical- For most patients with a destructive their previous activities. Sir John ly. Early mobilization after total hip process occurring in the hip joint, to- Charnley developed low-friction ar- replacement is recommended. While tal hip arthroplasty (THA) is a viable throplasty in the 1960s. Since then, complication rates are low, possible option. Since the first successful THA procedures have evolved to address postoperative problems include ve- was performed in the 1960s, proce- the issues of wear and bone loss and nous thromboembolism and nerve dures and the components used have permit joint replacement in patients injury in the short-term, and peri- evolved and we now have a better un- younger than 65. Pain is the prima- prosthetic fracture and osteolysis in derstanding of post-op considerations ry indication for a hip replacement, the long-term. If there is a failure of and possible complications. with osteoarthritis being the most the hip replacement for some rea- common cause. State-of-the-art im- son, the likelihood of a revision pro- History plants in 2016 include cemented, cedure succeeding is good. Beginning in the 1800s, a number of uncemented, or hybrid components; attempts were made at hip replacement for infection and fracture using implants of ivory, glass, ceramic, and metal. These trials continued through to the 1960s, when Sir John Charnley

Drs Ashman and Cruikshank are residents in the Department of Orthopaedics at the University of British Columbia. Dr Moran is an orthopaedic surgeon at the University Hospital of Northern BC and a clinical pro- fessor in the Department of Orthopaedics This article has been peer reviewed. at the University of British Columbia.

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developed the modern total hip often. These include metal-on-metal been resolved. Patients unable to per- replacement, which he called low- and ceramic-on-ceramic bearing sur- form activities of daily living or with friction arthroplasty.1 Charnley’s faces. While the risk of wear is mini- deformities such as a leg-length dis- procedure used a single-component mal with these articulations, metal- crepancy or flexion deformity are (monoblock) metal femoral stem and on-metal total hip arthroplasty has prime candidates for this operation. head combined with a cemented poly- been abandoned because of the many Such patients tend to have significant ethylene acetabular shell. The arthro- failures related to adverse local tissue pain. With the improving outcomes plasty of Charnley’s era survived for reactions to metal debris and the for- of hip replacement it is no longer many years but had problems. The mation of pseudotumors. Currently, necessary to wait until patients are 22.25-mm femoral head was prone the only hard-on-hard bearing surface completely disabled before considering surgery. Earlier intervention yields better outcomes provided that nonoperative treatments are no longer effective and the patient has pain that is related to the hip joint and not referred from the lumbar spine or With the improving outcomes related to extra-articular structures. of hip replacement it is no Pain from the hip joint is typi- cally located in the groin or buttock, longer necessary to wait until with referral to the thigh and often patients are completely disabled to the knee. Hip arthritis can present solely with knee pain, a finding espe- before considering surgery. cially common in elderly patients. All patients presenting with knee pain should undergo a physical examination of the hip and appropriate radio- graphs should be obtained if abnormalities are found during the hip to dislocation and the polyethylene available for a total hip arthroplasty examination. shell to eccentric wear. Larger femo- is ceramic-on-ceramic, and accord- ral heads were developed that reduced ing to joint registry data there is no Diagnoses the rate of dislocation, but at the cost evidence of superiority when ceramic Obviously, patients being considered of increased wear. Whatever the size and highly crosslinked polyethylene for THA need to have an underlying of the head, the cement mantle tended are compared at 10 years follow-up. condition that can be addressed using to loosen and then fail. The problem Today’s state-of-the art implants joint replacement. In broad terms, any of loosening was essentially solved include: patient with a pathology that leads to with the introduction of uncemented • Femoral heads of metal or ceramic. degeneration of the articular carti- components. However, failures con- • Acetabular liners of polyethylene or lage of the joint might benefit from tinued to occur with the breakdown ceramic. replacement of that joint. Osteoar- of the polyethylene and subsequent • Components that are cemented, un- thritis, whether idiopathic, develop- bone loss. cemented, or hybrid (uncemented mental, or posttraumatic, is by far Since the late 1990s, highly cross- acetabulum and cemented femur). the most common diagnosis lead- linked polyethylene with much im- ing to hip replacement surgery. This proved wear characteristics has been Indications includes osteoarthritis in the medial used with excellent results. Today The primary indication for total hip wall of the acetabulum, which is often wear and bone loss as a result of hip replacement is pain. Patients who are missed because the radiological find- replacement are exceedingly rare, unable to sleep because of pain will ings can be subtle and the presenting regardless of patient age or activity generally have a remarkable outcome symptoms can be somewhat unusu- level. In addition, so-called hard-on- from THA and will likely awake from al. For example, a patient may have hard articulations are being used more surgery to realize that their pain has pain at night and with certain activi-

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A B

Figure 1. Anteroposterior view of left hip (A) shows minor changes at the dome of the acetabulum and difficult-to-assess osteoarthritis (solid arrow) in the acetabular medial wall. Lateral view of the left hip (B) reveals osteoarthritis (dashed arrow) in the acetabular medial wall. ties because the medial wall of the hip will rarely change the manage- collapse and cause degeneration of the acetabulum is affected, but can still ment and should not be ordered if hip joint. However, the radiological have good walking tolerance because there is any evidence of degenera- findings are often not as pronounced the dome of the acetabulum (the tive arthritis. Hip-preserving surgery as the patient symptoms. MRI will weight-bearing surface) is relatively (hip arthroscopy or open dislocation reveal the extent of the disease but is unaffected. In these cases, the lateral and debridement) in the presence of not usually a necessary investigation radiograph can be helpful in assessing degeneration will not lead to a good unless the plain X-ray images do not medial wall osteoarthritis ( Figure 1 ). outcome and may lead to more rapid reveal any abnormalities early in the Over the past decade femoroac- progression of the arthritis and an ear- course of the disease. etabular impingement (FAI) has been lier need for a hip replacement. Inflammatory arthropathies such recognized as a precursor of and pos- Acetabular dysplasia involves a as rheumatoid arthritis, ankylosing sibly one of the ultimate causes of shallow or underdeveloped acetabu- spondylitis, and psoriatic arthritis all idiopathic osteoarthritis of the hip. lum that leads to early hip osteoar- present with degenerative changes The condition commonly occurs as thritis. As in cases of femoroacetabu- similar to those seen in osteoarthri- either cam FAI (deformity of the fem- lar impingement, patients older than tis and should be treated in the same oral neck) or pincer FAI (deformity 40 with acetabular dysplasia will not manner. of the acetabulum). The impingement benefit from osteotomies and labral caused by deformed hip bones even- repairs. The only effective surgi- Age tually leads to acetabular labral tears cal option is a total hip replacement. In the past, being younger than 65 and concomitant articular cartilage As such, there is no role for MRI in was considered a barrier to joint degeneration. Because the labral tears diagnosing acetabular dysplasia and replacement. This is no longer the are part of the degenerative process, degenerative change. case. Although patients with hip- the repair of these in patients older Avascular necrosis occurs when related pain should be counseled to than 40 without a bona fide injury the blood supply to the femoral head persist with nonoperative treatment and FAI is almost never indicated. is disrupted. In such cases the avas- until such time as their symptoms are An MRI or MRI/arthrogram of the cular portion of the femoral head can severe enough to warrant THA, it is

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important to recognize that patients contact during the joint articulation The main difference between mod- age 40 to 50 may be better served by consists of the femoral head and the ern implants and the original 1960s replacement than by hip arthroscopy acetabular liner. The search for the implants is the move away from the or further waiting. These patients are best materials to use in this bearing monoblock head-and-stem construct. not too young for hip replacement, surface have led to industry innova- The implant used by Charnley was a and the thinking that only patients tion and much debate. femoral stem and head that had been older than 65 should be offered THA Options today include a femoral machined as a single unit, whereas is no longer correct. head made of metal (cobalt and chro- current implants consist of a femo- As the bearing surfaces used for mium) or ceramic and an acetabular ral stem with a trunnion that permits hip replacement have improved, the liner made of metal, ceramic, or poly- attachment of a head and thus allows lifespan of implants has increased, ethylene. In British Columbia, the for more sizing options. In recent years, however, trunnion corrosion has led to pseudotumor formation similar to that experienced by patients with metal-on-metal total hip replacement.2 Although rare, these inflamma- Implants are now good enough to tory masses have been reported with metal-on-polyethylene hip replace- outlast the patient in most cases. ments and are thought to be related to metallic corrosion where the head of cobalt and chromium joins with the femoral stem, which in most cases is made of titanium. In North America currently, the and the age of the patient is not as Medical Services Plan covers the cost metal-on-polyethylene bearing sur- critical a consideration as it once of a cemented or uncemented femoral face is used most commonly.3 It has was. Implants are now good enough stem with a metal femoral head and a good wear characteristics, a high sur- to outlast the patient in most cases. metal acetabular shell with a polyeth- vivorship, and remains the workhorse Therefore, the status of the joint and ylene liner (either ultra high molecular of arthroplasty surgeons now that the symptoms of the patient, not the weight or highly crosslinked polyeth- the early problem of liner wear has age of the patient, should determine ylene). If a patient asks for a differ- been addressed. Originally, the pres- whether a THA is appropriate. ent component because of a perceived sure of the metal femoral head on the benefit, there is an additional charge softer polyethylene liner produced an Implants since no benefit has been found with eccentric wear pattern that eventu- Many implant designs have been other articulating surfaces. ally led to joint failure and the need used during the development of total for revision.4 Over the last 15 years or hip arthroplasty. Research into vari- Metal-on-polyethylene bearing so the use of crosslinked polyethylene ous implant materials and different surface has significantly reduced the rate of shapes and sizes of both the femoral In the 1960s, Charnley pioneered the wear, and revisions for polyethylene and acetabular components has made use of a metal femoral head and an wear are now uncommon. this field a diverse and exciting one. acetabular component of ultra high During a total hip arthroplasty molecular weight polyethylene. This Ceramic-on-ceramic and procedure, the degenerated femoral metal-on-polyethylene bearing sur- ceramic-on-polyethylene head and acetabulum are replaced face was adapted from the impact bearing surface with a metal femoral stem and head bearings used for looms in the textile An alternative to metal-on- (cemented or uncemented), a metal industry.1 polyethylene is a bearing surface of acetabular shell (cemented or unce- Since Charnley’s time, only a few medical grade ceramic. The ceramic- mented), and an acetabular liner that improvements have been made, and on-ceramic bearing surface is more locks into the acetabular shell. The the metal-on-polyethylene bearing expensive but has better wear char- bearing surface that takes the force of now has an excellent track record. acteristics, reduced particulate debris

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generation, and greater biocompat- in total hip arthroplasty. The advan- ibility.5 tages included low volumetric wear, The use of ceramic bearings is high resistance to implant fracture, increasing in North America and and lower rates of dislocation with is used in the majority of cases in the increased femoral head sizes per- Europe. Earlier generations of ceram- mitted by large-head metal-on-metal ic were relatively brittle, which lead to THA.8 a high risk of component fracturing.6 This enthusiasm was short lived, Improvements in ceramic technology however. It has now been well docu- and manufacturing techniques have mented that patients with a metal-on- dramatically reduced the incidence of metal THA have elevated serum lev- implant fracturing5 along with the risk els of cobalt and chromium, of which of squeaking from the hip with walk- the clinical effects are unknown. Fur- ing and bending motions.7 Despite ther, it has been discovered that in the potential advantages of a ceramic- some patients the metallic ion wear on-ceramic bearing surface, the rate debris leads to formation of benign of revision at 10 years is identical to solid or cystic masses. Investiga- that of metal-on-polyethylene and the tions have found that the prevalence cost is greater. While the ceramic-on- of these pseudotumors in asymp- ceramic bearing surface is considered tomatic patients with metal-on-metal an option for young, active patients implants is unacceptably high.9 Given who require a total hip arthroplasty,7 the complications and the high revi- the routine use of ceramic-on-ceramic sion rates for large-head metal-on- instead of metal-on-polyethylene is metal implants, this bearing surface Figure 2. Total hip replacement with cemented components. not considered cost-effective. is no longer an option for total hip An alternative to the standard arthroplasty. ceramic-on-ceramic bearing is a ceramic femoral head with a poly- Cemented versus uncemented ethylene liner. This ceramic-on- implants polyethylene bearing surface does not A major consideration in THA is pose a squeaking risk and is cheaper whether to use a cemented or an unce- than a ceramic-on-ceramic bearing. mented implant. Early procedures While the wear rates of ceramic-on- relied on polymethylmethacrylate polyethylene and metal-on-poly cement from the dental industry,10 a ethylene are not appreciably different, bonding agent that failed to adequate- the risk of pseudotumor formation ly secure arthroplasty implants to from metallic debris is eliminated with bone. Charnley recognized that rather the use of ceramic-on-polyethylene. than using the cement for bonding, he Despite this advantage, the routine should use it as a grout to create an use of ceramic-on-polyethylene is interface between the porous meta not considered to be cost-effective physeal and cortical bone and the because of the rarity of pseudotumors metal implant in order to greatly in the large number of hip replace- increase the surface contact area and ments done annually and the higher achieve long-term stability. While cost of ceramic implants. cemented implants ( Figure 2 ) are still favored in some parts of the world, Metal-on-metal bearing surface including Sweden and Norway,10 From the late 1990s to the early 2000s the most common type of prosthesis there was a resurgence in the use of in North America is an uncemented Figure 3. Total hip replacement with a metal-on-metal bearing surface implant ( Figure 3 ). uncemented components.

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In uncemented techniques, both The use of hip resurfacing has have not resulted in higher dislocation the femoral and acetabular com- declined dramatically worldwide over rates when patients undergo an ante- ponents are coated with a porous the past few years, but remains a via- rior or anterolateral approach THA. material that encourages the bone to ble option for young, active patients Similarly, there is no strong evidence grow into the surface of the implant. with disabling osteoarthritis. While for higher dislocation rates with Initial stability depends on having the hip resurfacing must be used with precaution-free post-op protocols implant firmly pressed into the bone, caution, it can lead to good and long- when patients undergo a posteri- and long-term stability is gained by lasting outcomes when performed by or approach replacement.13 While the bone bonding to the implant. In an experienced surgeon and in a well- patients are encouraged to observe some cases, such as when the femo- selected patient. Currently the proce- hip precautions, a commonsense ral bone is of poor quality and can- dure is not recommended for women, approach should be followed and not support a firmly press-fit femoral men of small stature, or patients older patients should not be too worried component, cement can be used. This than 65. about dislocation, which remains a is known as a hybrid THA, in which relatively rare complication provided the acetabular component is unce- Post-op considerations the implants are positioned correctly. mented, but the femoral component After patients have undergone total is cemented. There is no substan- hip arthroplasty, they should be en- Venous thromboembolism tial difference in outcome between couraged to mobilize early and to ob- Venous thromboembolism is a well- uncemented and hybrid fixation tech- serve hip precautions. Patients should documented complication of total niques, and the choice of fixation also be monitored for possible com- hip arthroplasty. THA patients are at depends on surgeon experience and plications. Complications that may particular risk because of both intrao- patient characteristics. occur in the short-term are: perative endothelial trauma and ven- • Venous thromboembolism (VTE) ous stasis from relative immobiliza- Hip resurfacing • Prosthetic joint infection tion in the perioperative period. A Hip resurfacing is an alternative to • Nerve injury recent systematic review found ap- the traditional total hip arthroplasty, • Vascular injury proximately 1 in 200 patients (0.53%) which requires the removal of the • Bleeding developed symptomatic VTE prior to femoral head and neck. In a resurfac- • Leg-length discrepancy hospital discharge following hip arth- ing procedure, the femoral head is • Dislocation/instability roplasty despite receiving VTE pro- machined to accept a metal cap and • Fracture phylaxis.14 This same study found the acetabulum is replaced in a man- Complications that may occur in rates of symptomatic VTE events oc- ner similar to that used for THA. In the long-term are: curred in approximately 2% to 5% this way the large-diameter head and • Prosthetic joint infection of hip arthroplasty patients within 3 acetabular component make a metal- • Periprosthetic fracture months of surgery.14 The rate of clin- on-metal bearing surface. • Dislocation/instability ically asymptomatic VTE events is The advantages of a hip resurfac- • Polyethylene wear higher still but clinical relevance of ing procedure include the maintenance • Osteolysis asymptomatic VTE is not known.14 of bone stock, which can eventually The American Academy of Or- be converted to a THA should the re- Mobilization and hip precautions thopaedic Surgeons (AAOS) and the surfaced joint wear out or fail. The Postoperative patient mobilization American College of Chest Physi- disadvantages include a risk of femo- should begin within 24 hours of hip cians (ACCP) have published guide- ral neck fracture and the risks that go replacement surgery.12 Benefits of lines regarding VTE prophylaxis in along with a metal-on-metal bearing early mobilization include decreased joint arthroplasty patients.15,16 The surface, such as elevated serum levels risk of venous thromboembolism, AAOS guidelines state that moderate of metal ions and adverse tissue reac- shorter inpatient stay, and lower total evidence supports the use of pharma- tions. However, it has been shown that cost of care.12 cological and/or mechanical VTE pro- the serum metal ion concentrations Hip precautions following THA phylaxis for routine hip replacement, generated by hip resurfacing are much have become routine in postopera- but do not recommend one particular less than those generated by a large- tive care. Recent research suggests prophylactic regimen over another head metal-on-metal THA.11 precaution-free post-op protocols because of inconclusive evidence.16

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The ACCP guidelines state that grade monary embolism and require antico- (with or without erythrocyte sedi- 1B evidence supports the use of ei- agulation. Because DVT/PE after hip mentation rate), and obtaining sterile ther low molecular weight heparin, replacement is a provoked event, anti- joint aspirate for culturing and sensi- fondaparinux, apixaban, dabigatran, coagulation is not required long-term tivity testing and cell count with dif- rivaroxaban, low-dose unfractionated and may be stopped after 3 months ferential. Obtaining aspirate prior to heparin, warfarin, or aspirin for VTE unless the condition is a recurrent initiating systemic antibiotic therapy prophylaxis in THA patients. Fur- one, in which case the patient should prevents compromising the diagnos- thermore, the ACCP cites grade 1C be referred to a thrombosis clinic or tic value of the aspiration and allows evidence for intermittent pneumatic to a hematologist to see if long-term selection of an appropriate antibi- compression devices as mechanical anticoagulation is indicated. otic. A prospective multicentre study VTE prophylaxis.15 Following surgery, patients who develop VTE can remain asymptomatic, experience leg swelling suggestive of deep vein thrombosis (DVT), or exhibit one or more of the following A methodical approach to symptoms suggestive of pulmonary the evaluation and management embolism (PE): tachycardia, short- ness of breath, chest pain, hemopty- of surgical wounds following 17 sis, hypotension, anxiety. Knowing THA is critical. the likelihood of VTE developing and promptly recognizing the signs and symptoms can permit early workup and treatment to limit morbidity, reduce cost of care, and prevent mor- tality. It should be emphasized that a Prosthetic joint infection of arthroplasty patients compared D-dimer assay has no role in the post- Prosthetic joint infection is a serious results from superficial cultures of op workup given the expected eleva- complication that occurs in 1% to 2% wound exudate with deep cultures of tion of D-dimer levels due to recent of patients and has negative effects on intra-articular tissue or aspirate and surgery.18 Duplex Doppler ultrasound patient morbidity and satisfaction and found poor concordance, with many can help in the diagnosis of DVT, on the overall cost of care. A method- superficial cultures yielding bacterial but should not be used to scan the ical approach to the evaluation and growth while deep cultures and fur- calf because a diagnosis of calf DVT management of surgical wounds fol- ther workup suggested the absence based on duplex Doppler ultrasound lowing THA is critical. Postopera- of infection. Based on these findings, is unreliable and the risk of embolism tive wound infection can result from the authors of the study recommend from calf DVT is very low in the post- surgical contamination, contiguous against the use of superficial cultures operative setting and does not warrant spread, or hematogenous spread.18 to prevent misdiagnosis and medical the risk of anticoagulation. CT pul- Acute THA wound infections mani- or surgical mismanagement.19 Ide- monary angiography (or ventilation- fest within days or weeks of surgery ally, when patients present with con- perfusion scan in patients unable to and present with localized hip pain, cerning surgical wounds, workup for undergo CT angiography) is the test swelling, erythema, and warmth. infection and prompt follow-up with of choice to assess for pulmonary Wound drainage or a draining sinus their surgeon or an on-call orthopae- embolism.18 When the radiologist tract may be evident and the presen- dic surgeon should occur before anti- reports a filling defect on a CT pulmo- tation can include fever, malaise, and biotics are initiated. nary angiogram, it needs to be noted frank sepsis.18 Chronic wound infec- Until recently, patients with ortho whether this is a segmental or subseg- tions present more subtly but are com- paedic implants, including hip re- mental filling defect. Subsegmental monly associated with pain. Standard placements, were routinely given an- filling defects do not require antico- workup for wound infection includes tibiotic prophylaxis when undergoing agulation. Segmental filling defects obtaining blood for culturing and low- or high-risk dental procedures are consistent with a diagnosis of pul- WBC and C-reactive protein testing to prevent prosthetic joint infections.

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Clinical practice guidelines released lous. Preoperative cessation of anti- solves within 3 months and does not in 2012 by the AAOS in conjunction coagulants should be undertaken, and require any specific treatment. Intra- with the American Dental Associa- the use of tranexamic acid for bleed- operative fracture can happen on the tion now recommend against antibi- ing prophylaxis should be consid- acetabular or, more commonly, the otic prophylaxis for dental procedures ered.18 Patients should also be coun- femoral side during bony preparation because of a lack of evidence that seled preoperatively regarding the or implant insertion. If identified in- dental-procedure-induced bacteremia possible need for perioperative blood traoperatively, additional fixation is leads to prosthetic joint infections. transfusion, although this is becom- often necessary to ensure prosthesis The grade of recommendation for this ing rare in patients with a preopera- stability. Postoperative recognition of is designated as Limited.20,21 tive hemoglobin level over 125 g/dL. fracture, especially involving the acetabulum, could alter clinical course and may require revision surgery to ensure implant stability.18 Hip instability or dislocation occurs in approximately 1% to 3% of THA patients and is the second most common indication for revision sur- The incidence of nerve injury gery after infection. Dislocation most commonly happens within 1 month following THA is approximately of surgery.17 Numerous factors can 1 to 2 cases per thousand. lead to instability, including infection, trauma, patient noncompliance, implant wear or loosening, pseudotumor formation, and component mal- position. Treatment of a dislocated prosthesis is closed reduction under procedural sedation with orthopaedic referral.18 Recurrent dislocations gen- Other complications Leg-length discrepancy may oc- erally require revision surgery. The incidence of nerve injury fol- cur following THA. Patients tend to Periprosthetic fractures secondary lowing THA is approximately 1 to tolerate up to 2 cm of LLD without to trauma can occur at any point post- 2 cases per thousand, with the pero- need for treatment, but a greater dis- operatively. Immediate orthopaedic neal branch of the sciatic nerve and crepancy can become clinically im- referral is required to determine the the femoral nerve most commonly portant, potentially manifesting as need for operative fixation or revision affected.17 Multiple causes must be knee, hip, or lumbar pain or as gait arthroplasty. considered, including traction injury, disturbance.18 Most symptomatic Components wear over time with compression, and direct trauma, al- LLD can be treated with a shoe lift. repetitive loading and friction within though in many cases the cause will In patients requiring bilateral THA, the artificial joint; this natural wear remain unknown. Prognosis tends to subsequent arthroplasty on the con- process can be exacerbated by com- be favorable for partial, if not full, tralateral hip may actually balance ponent malpositioning.18 Research return of function, but depends on out the inequality. It is not unusual for into implant biomechanics is con- the cause of the injury. Support- patients with no measurable LLD to tinuing in an attempt to maximize ive treatment, including a foot drop complain that the surgical limb seems component lifespan by minimizing orthosis for sciatic nerve palsies, is longer. This is known as a functional wear. Wear debris, particularly from recommended.17,18 leg-length discrepancy and is related the breakdown of polyethylene, trig- While vascular injury is exceed- to mobilization of a previously stiff gers an immune response and can ingly rare during THA surgery,18 hip in which the hip is held in an ab- lead to prosthesis instability and oste- bleeding in the perioperative period ducted position to avoid dislocation olysis. This bone resorption, in turn, remains a well-established risk even and also due to weak hip abductor can cause component loosening and when surgical technique is meticu- muscles. In most patients, this re- pain.18 Osteolysis is a complication

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of older implants from the 1990s al. Adverse local tissue reactions on metal- 13. Husted H, Gromov K, Malchau H, et al. and earlier, and is seen rarely now. on-polyethylene total hip arthroplasty due Traditions and myths in hip and knee arth- Implant loosening can still be seen, to trunnion corrosion. Bone Joint J roplasty. Acta Orthop 2014;85:548-555. however, and is related to either the 2015;97B:1024-1030. 14. Januel JM, Chen G, Ruffieux C, et al. failure of the cement or the failure of 3. Lehil MS, Bozic KJ. Trends in total hip Symptomatic in-hospital deep vein throm- bone ingrowth in uncemented com- arthroplasty implant utilization in the Unit- bosis and pulmonary embolism following ponents. Patients with persistent hip ed States. J Arthroplasty 2014;29:1915- hip and knee arthroplasty among patients pain following THA, especially of 1918. receiving recommended prophylaxis: A new onset, should be re-referred to 4. Abu-Amer Y, Darwech I, Clohisy JC. Asep- systematic review. JAMA 2012;307:294- their orthopaedic surgeon for workup. tic loosening of total joint replacements: 303. If there is a failure of a hip re- Mechanisms underlying osteolysis and 15. Falck-Ytter Y, Francis CW, Johanson NA, placement due to infection, osteoly- potential therapies. Arthritis Res Ther et al. Prevention of VTE in orthopedic sur- sis, periprosthetic fracture, or some 2007;9(suppl 1):S6. gery patients: Antithrombotic therapy and other cause, the likelihood of a revi- 5. Masson B. Emergence of the alumina ma- prevention of thrombosis, 9th ed: Amer- sion procedure succeeding is good. trix composite in total hip arthroplasty. Int ican College of Chest Physicians evi- Revision THA produces results that Orthop 2009;33:359-363. dence-based clinical practice guidelines. approach those of the initial surgery. 6. Boutin P. Total hip arthroplasty using a ce- Chest 2012;141(suppl 2):e278S-e325S. ramic prosthesis. Pierre Boutin (1924- 16. Jacobs JJ, Mont MA, Bozic KJ, et al. Summary 1989). Clin Orthop Relat Res 2000;(379):3- American Academy of Orthopaedic Sur- Total hip arthroplasty can relieve 11. geons Clinical Practice Guideline on: Pre- pain, restore function, allow patients 7. Aoude AA, Antoniou J, Epure LM, et al. venting venous thromboembolic disease to return to normal activities, and is Midterm outcomes of the recently FDA in patients undergoing elective hip and a viable option for most patients with approved ceramic on ceramic bearing in knee arthroplasty. J Bone Joint Surg Am a degenerative process occurring in total hip arthroplasty patients under 65 2012;94:746-747. their hip joint. In BC the standard of years of age. J Arthroplasty 2015;30: 17. Lieberman JR (ed). AAOS comprehen- care for hip implants is a metal ace- 1388-1392. sive orthopaedic review. Rosemont, IL: tabular shell with a polyethylene liner 8. Jacobs JJ, Urban RM, Hallab NJ, et al. American Academy of Orthopaedic Sur- and a cemented or uncemented femo- Metal-on-metal bearing surfaces. J Am geons; 2009. ral stem with a metal femoral head. Acad Orthop Surg 2009;17:69-76. 18. Nutt JL, Papanikolaou K, Kellett CF. Com- Early mobilization after total hip 9. Williams DH, Greidanus NV, Masri BA, et plications of total hip arthroplasty. Orthop replacement is recommended. While al. Prevalence of pseudotumor in asymp- Trauma 2013;27:272-276. complication rates are low, possible tomatic patients after metal-on-metal hip 19. Tetreault MW, Wetters NG, Aggarwal VK, postoperative problems can include arthroplasty. J Bone Joint Surg Am 2011; et al. Should draining wounds and sinuses venous thromboembolism, prosthet- 93:2164-2171. associated with hip and knee arthroplas- ic joint infection, and periprosthetic 10. Troelsen A, Malchau E, Sillesen N, Mal- ties be cultured? J Arthroplasty 2013; fracture. When a hip replacement fails chau H. A review of current fixation use 28:133-136. for some reason, there is a good like- and registry outcomes in total hip arthro- 20. Watters W, Rethman MP, Hanson NB, et lihood that a revision procedure will plasty: The uncemented paradox. Clin Or- al. Prevention of orthopaedic implant in- succeed. thop Relat Res 2013;471:2052-2059. fection in patients undergoing dental pro- 11. Garbuz DS, Tanzer M, Greidanus NV, et al. cedures. J Am Acad Orthop Surg 2013; Competing interests The John Charnley Award: Metal-on-met- 21:180-189. None declared. al hip resurfacing versus large-diameter 21. Jevsevar DS, Abt E. The new AAOS-ADA head metal-on-metal total hip arthroplas- clinical practice guideline on prevention of References ty: A randomized clinical trial. Clin Orthop orthopaedic implant infection in patients 1. Gomez PF, Morcuende JA. A historical Relat Res 2010;468:318-325. undergoing dental procedures. J Am Acad and economic perspective on Sir John 12. Stowers MD, Lemanu DP, Coleman B, et Orthop Surg 2013;21:195-197. Charnley, Chas F. Thackray Limited, and al. Review article: Perioperative care in the early arthroplasty industry. Iowa Or- enhanced recovery for total hip and knee thop J 2005;25:30-37. arthroplasty. J Orthop Surg (Hong Kong) 2. Whitehouse MR, Endo M, Zachara S, et 2014;22:383-392.

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