最新进展

Studies have demonstrated total joint arthroplasty to be a highly cost-effective procedure. Nevertheless, many payers, especially the U.S. Centers for Medicare & Medicaid Services (CMS), have targeted total joint arthroplasty for cost control20. Adoption of a pay-for-performance program by CMS21 has created a zero-sum game to reward overachievers and penalize underachievers.

    The current literature lacks a detailed, comprehensive approach for risk-stratifying total joint arthroplasty patients and a systematic method for preoperatively allaying these risks. Popular tools such as the American Society of Anesthesiologists (ASA) classification system may be effective in predicting the overall outcome of surgery, but they cannot predict specific complications 22 and they do not facilitate further preparatory action23-25. Although medical evaluation should be performed in collaboration with the internist, evidence-based guidelines provide standardization and comprehensiveness. Conditions necessitating postponement or cancellation of total joint arthroplasty are present in approximately 4% of patients26. 

    初次全髋关节置换术和全膝关节置换术的需求在美国日益增高，预计未来20年内分别将增长174%和673%。大部分患者术后满意度为好和极好。现代手术技术和围手术期处理进一步的降低了全身和局部并发症。但髋膝关节置换术仍有2.2-7.4%的主要不良反应和0.1-0.8%的死亡率。如何进一步提高围手术期治疗从而降低并发症仍是广大关节外科医生所关注的问题。

尽管关节置换术是一个高性价比的医疗行为，但仍然有很多纳税人，尤其是美国医疗保险和医疗补助服务中心(CMS)希望进一步降低成本。CMS采用基于绩效的薪酬管理取得零和博弈，从而奖励低成本医疗过程、惩罚高成本医疗过程。

目前尚缺乏具体的、全面的方法来对关节置换术患者进行风险评估，也缺乏系统的方法在围手术期降低患者风险。目前常用的工具如美国麻醉医师协会评分系统（ASA）可能在评估术中风险上有效，但他并不能预测手术相关并发症，也不能指导相应的预防治疗。尽管医疗评估需要内科医生的协助，但循证医学可以提供标准且详尽的指南。目前仍有约4%的需关节置换患者因为各种情况需要推迟或取消手术。

Cardiovascular Conditions

    Complications related to the cardiovascular system represent 42% to 75% of major systemic adverse events and deaths following total joint arthroplasty7,13,27,28, and cardiovascular comorbidities are a significant risk factor for these events14,29. Intramedullary instrumentation and cementation cause marrow embolization and result in cardiac stress30. The in-hospital prevalence of myocardial infarction is 1.8%, occurring at a mean of three days postoperatively31. The American College of Cardiology and the American Heart Association published guidelines for perioperative cardiovascular evaluation32, which are summarized in Tables I through IV. 

Elective surgery is not recommended within four to six weeks after implantation of a bare-metal coronary stent, twelve months after implantation of a drug-eluting stent, or four weeks after balloon angioplasty32. Dual antiplatelet therapy is prescribed to minimize the risk of thrombosis before endothelialization of the stent occurs33, and premature drug cessation is an important predictor of death and major ischemic events34. Substitution of heparin may not prevent complications, and thrombosis is associated with a 45% mortality rate33. A cardiologist should provide explicit instructions regarding pharmaceutical prophylaxis Ideally, elective total joint arthroplasty should be deferred for at least twelve months after stent implantation or balloon angioplasty, and aspirin should be continued throughout the perioperative period for the arthroplasty. Clopidogrel for patients with cardiac stents appears to be safe during the perioperative period, incurring only a small increased risk of bleeding and hematoma formation35. Implantable cardioverter-defibrillators or pacemakers should be tested within three to six months preoperatively32. Atrial fibrillation increases the risk of stroke by twentyfold and should be adequately controlled prior to surgery36. 

Hypertension is the foremost cause of cardiovascular disease37, affecting 25%of patients. Only 72%of individuals with hypertension are aware of their condition, and less than one-third are adequately treated38. Stage-2 hypertension (<180/110 mm Hg) is not an independent risk factor for perioperative complications, and such hypertension alone does not warrant delay of surgery32,39. Antihypertensive medications should be continued perioperatively, and physicians should be vigilant for blood pressure lability and hypotensive episodes. 

Although orthopaedists rarely auscultate the heart, murmurs should not be ignored. Patent foramen ovale is present in 25% of patients40. This is normally a benign lesion41, but it is described as a risk factor for cryptogenic stroke42-45. Perioperative stroke occurs in 0.2% of total joint arthroplasty patients, and the majority of such strokes are caused by ischemia46-48. Percutaneous closure of a patent foramen ovale is a relatively benign procedure42, but it is uncertain whether it would be beneficial in high-risk patients41. 

心血管情况

    心血管系统并发症以及相应引起的死亡是关节置换术后主要不良事件，其占关节置换术后不良事件的42-75%，患者本身存在心血管系统疾病是该事件的高危因素。骨骼的髓内操作和骨水泥注入能引起骨髓栓塞从而导致心脏负荷增高。调查显示院内心肌梗塞发生率为1.8%，平均发生时间为术后三天内。表格I-IV为美国心脏病学会和美国心脏协会围手术期心血管系统评估指南（由于表格比较专业我就不一一翻译了）。

金属冠状支架植入后4-6周内、药物洗脱支架植入后12月内，气囊血管成形术后4周内不建议行非急诊手术。双重抗血小板治疗常用于支架植入之前以保证血栓风险最小化，过早停用抗血小板药物是缺血事件以及相关死亡的重要危险因子，肝素替代治疗并不能预防该类并发症，总之血栓相应并发症占总体死亡45%的比例。心血管医生应提供详尽的预防性用药说明，择期关节置换术应至少在支架植入术或气囊血管成形术后12个月后进行，阿司匹林应关节置换围手术期持续使用，支架植入患者围手术期应用氯吡格雷（抑制血小板药物）虽然会导致出血和血肿形成的风险轻度增加但总体上是安全的。植入的心脏电复律器-除颤器和起搏器应该在术前3-6个月进行检测。心房纤颤会引起中风的风险增加20倍，因此在手术前应给予恰当控制。

高血压是最常见的心血管疾病，约有25%患者罹患高血压。这些患者中只有72%知道他们患有高血压，而血压得到有效控制的往往少于三分之一。二级高血压(<180/110 mm Hg)并不是围手术期并发症的独立危险因素，也不需要因此推迟手术。围手术期应控制好血压，减少血压的大幅波动和低血压的发生。

尽管骨科医生极少听诊心音，但必须排除心脏杂音的存在，有25%的患者存在卵圆孔未闭，虽然一般是良性病变，但有研究表明这是不明原因中风的危险因子。关节置换术患者中风的发生率为0.2%，通常是缺血型中风。尽管经皮行卵圆孔闭塞术创伤很小，但此操作是否对高危患者有利尚不确定。

Rheumatoid Conditions

    Approximately 2.6% to 7% of osteoarthritic patients have psoriasis, and 7% to 42% of patients with psoriasis have arthritis49. Psoriatic lesions are marked by silver, scaly, round plaques, have higher bacterial counts than adjacent normal skin50, and are exacerbated by stress. Infection rates after total joint arthroplasty range from2%to 17%in patients with both arthritis and psoriasis51-53. Skin lesions have a predilection for extensor surfaces and intertriginous folds, and it is reasonable to delay surgery and to clear the plaques if the skin near the surgical site is compromised. According to the National Psoriasis Foundation, data on the effect of psoriasis on the risk of infection are limited and conflicting 

Patients with rheumatoid arthritis have similar mortality risks to controls, and no consensus exists regarding whether rheumatoid arthritis is associated with an elevated risk of periprosthetic joint infection55-61. Well-timed arthroplasty and improved pharmacotherapy have improved survival62. Disease modifying antirheumatic drugs, anti-inflammatory drugs, and biologic agents can compromise immunity and wound-healing. Their use in the perioperative period should be weighed against the risk of a rheumatoid arthritis flare-up63. A short corticosteroid tapering-off period is often necessary preoperatively to counteract the stress of surgery63. A rheumatologist should be consulted regarding the optimal pharmaceutical regimen (Table V). Sixty-one percent of patients with rheumatoid arthritis who are undergoing elective total joint arthroplasty have cervical spine instability, and >50% of these are symptomatic64. Cervical radiographs should always be made prior to arthroplasty surgery (Table VI)65. 

    The odds ratio for death in patients with systemic lupus erythematosus compared with controls is >3 after total hip arthroplasty and 2.5 after total knee arthroplasty66. Additionally, this condition is associated with a greater risk of wound complications67. To our knowledge, no specific recommendations to prevent these risks are available. 

    大约有2.6-7%的OA患者患有牛皮癣，而7-42%的牛皮癣患者罹患各种关节炎。银屑病病变特点为病灶呈银色、鳞片状、圆形斑块，有细菌数量比相邻的正常皮肤高，刺激下病情会加重。同时罹患关节炎和牛皮癣患者关节置换术后感染率为2-17%。牛皮癣的好发部位为肢体伸肌处皮肤和有损伤的皮肤，如果病灶临近手术区域最好推迟手术并治疗病灶。根据国家牛皮癣基金会数据，牛皮癣与术后感染率的关系尚不明确。

RA患者的死亡率与对照组相近，RA患者关节置换术后感染率是否增高目前尚未达到共识。恰当时机进行关节置换术以及最新的药物治疗能够有效提高患者的生存率。抗风湿药物、抗炎症药物以及相关生物制剂会损害患者的免疫力和伤口愈合能力。围手术期使用该类药物应权衡利弊。术前往往需要短期使用短效糖皮质激素以中和手术应激。应咨询风湿科医生以获得最佳的药物处方。需关节置换的RA患者中约61%合并颈椎不稳定，大于50%有颈椎不稳的相关征管，因此术前应给予颈椎照片。

SLE患者死亡率与对照组比较，全髋关节置换术后增加3倍，全膝关节置换术后增加2.5倍。此外，患者伤口并发症的发生率也大大提高，据我们所了解，目前尚没有相关措施降低该类风险。

Immunosuppression

    Recipients of solid-organ transplants often require chronic corticosteroid treatment as prophylaxis against posttransplant rejection. This causes increased vulnerability to infection. The risk of opportunistic infection is highest within the first six months after renal transplantation, and such infections are associated with a 29% mortality rate68. Transplant recipients have elevated risks of periprosthetic infection (9%)69, hip prosthesis dislocation (0% to 16.7%), venous thromboembolism (1.8% to 9%), and death (42% at fifteen years)70. Nevertheless, total joint arthroplasty provides good results in recipients of most types of solid-organ transplants70,71. Surgeons should have a high index of suspicion for early infection71. 

      器官移植患者常常需要长期服用糖皮质激素以预防排斥反应，这将导致感染的风险增加。肾移植患者术后头六个月发生机会性感染的风险最高，而此类感染的死亡率高达29%，移植患者关节置换术后假体周围感染率为9%、关节脱位率为0-16.7%，静脉血栓栓塞症发生率为1.8-8%，术后15年死亡率为52%。尽管如此，大部分移植患者关节置换术的疗效满意，手术医生仅需高度警惕早期感染的发生。

Intravenous Drug Abuse, Alcoholism, and Human Immunodeficiency Virus (HIV) 

    Intravenous drug abuse is a risk factor for bacteremia72 and periprosthetic joint infection73. In a small case series, 25% of total joint arthroplasty patients who were intravenous drug abusers developed a periprosthetic joint infection from hematogenous spread74. Patients with a history of intravenous drug abuse should be referred to a methadone clinic and be clean (as confirmed by intermittent physical examinations and drug screenings) for at least two years before total joint arthroplasty74. Infection with HIV is an independent risk factor for periprosthetic infection and has been associated with infection rates ranging from 13% to 25%. When HIV is combined with intravenous drug abuse, the infection rate is up to 60%74,75. It is reasonable to require full antiviral therapy, stable CD4 counts of >200 cells/mL, low viral titers, and a clearance recommendation from an HIV specialist before considering total joint arthroplasty in patients with HIV74,75. 

    Alcohol abuse is associated with increased postsurgical morbidity76,77 and delirium78. There is a 25% risk of dislocation after total hip arthroplasty in patients who drink >72 oz (2.1 L) per day of beer or >6 oz (177 mL) per day of other alcoholic beverages79-81. The CAGE questionnaire82 is the best known alcohol use questionnaire. However, a simple validated screening instrument, the AUDIT-C questionnaire (Table VII), is highly predictive; for every 1-point increase above 1 point, complications increase by 29%83. Abstinence for at least one month preoperatively significantly decreases postoperative morbidity84, but shorter periods do not make a difference85. Patients who abuse alcohol should be evaluated for liver disease and malnutrition 

    瘾君子常高发菌血症和假体周围感染，有研究显示，25%的该类患者发生血源性假体周围感染。因此具有滥用静脉药物注射的患者应给予至少2年的美沙酮药物治疗，并经定期体格检查和药物筛查以明确戒毒方能考虑手术。HIV感染是假体周围感染的独立危险因素，感染率高达13-25%。尤其对于HIV患者同时滥用静脉药物注射时，感染率高达60%。对于这类患者，必须进行全程抗病毒治疗，检查发现CD4稳定高于200 cells/mL、HIV病毒含量低并戒毒成功方能考虑手术。酗酒者术后死亡率和谵妄发生率增高，当患者日饮啤酒超过2.1L，日饮其他酒类超过177ml时，全髋关节置换术后关节脱位率高达25%。各类酗酒调查表中CAGE调查表最为著名，但AUDIT-C调查表就具有极高的预测性，AUDIT-C评分没增加1分，并发症的发生率增加29%。术前戒酒1月可明显降低术后并发症发生率，但短于1月无明显效果。酗酒者术前应评估肝功能及营养情况。

Dental Pathology

    Approximately 2% of total joint arthroplasty infections involve organisms found in the oropharynx, and most affected patients have preexisting cavities or oral abscesses86. Dental caries or infected gums requiring treatment are present in 15% to 23% of patients undergoing total joint arthroplasty 87,88. Antibiotic prophylaxis before substantial dental procedures in patients who have undergone total joint arthroplasty is controversial; authors of 74% of the prior literature on the topic take no clear position89. The American Academy of Orthopaedic Surgeons (AAOS) suggests prophylaxis in patients at high risk of hematogenous or prosthetic infection90, and the American Academy of Oral Medicine (AAOM) expresses concern that those recommendations have been extended to include all patients with a total joint arthroplasty, regardless of the underlying risk91. Bacteremia from dental procedures can cause seeding and sepsis of the prosthetic joint92-95. Treatable dental issues should be screened for and treated before total joint arthroplasty86,87,89. 

    大约有2%的术后感染患者病原菌来源于口腔，大部分患者先前存在龋齿或口腔脓肿。15-23%的合并龋齿或口腔感染关节置换患者术前需要相关治疗，该类关节置换患者在治疗牙科疾患时是否需要预防性应用抗生素尚却在争议。74%的该类研究并为给予明确结论。AAOS建议对于术后感染高风险患者给予预防性抗生素，AAOM则建议对于所有该类患者给予抗生素。牙源性病菌可经血种植于假体部位并引起局部脓肿，因此建议术前检查口腔情况并给予相应治疗。

Obesity

    Obesity increases the risk of complications in total joint arthroplasty patients96-98. One-half of total knee arthroplasty patients and one-third of total hip arthroplasty patients are obese (body mass index [BMI] > 30 kg/m2)99,100. The authors of nearly all studies report an increase, ranging from fourfold to nearly tenfold, in the prevalence of infection in obese and morbidly obese patients (BMI > 40 kg/m2)96,99,101-104. Diabetes compounds the risk associated with obesity105. Excess fat necessitates longer incisions and lengthier tourniquet times, resulting in more fat necrosis and greater wound complications96,106,107. Each day of prolonged drainage increases the risk of infection by 29% to 42%108. Obesity is associated with acetabular malpositioning109 and dislocation in total hip arthroplasty101,110 and with technical errors111 and medial collateral ligament avulsion in total knee arthroplasty103,106. Super obesity (BMI > 50 kg/m2) is associated with a twenty-onefold increase in the risk of infection102 and a complication rate of >50%112,113. However, some other studies do not support significant differences in complications in obese compared with nonobese patients100,114-118. Total joint arthroplasty provides functional improvement and patient satisfaction in obese and even morbidly obese patients104,119, but obesity remains a risk factor for inferior results when obese patients are matched with controls120,121. 

    肥胖患者关节置换术后并发症发生率增高，大约有一半的全膝关节置换术患者和三分之一全髋关节置换术患者BMI> 30 kg/m2。对于BMI> 40 kg/m2的肥胖患者术后感染率约为正常体重患者的4-10倍。肥胖患者常伴有糖尿病，肥胖意味着皮下脂肪过多，手术常需要更长的切口和更长时间应用止血带，这导致脂肪坏死和伤口并发症发生率增高，引流管留置时间延长，感染率约为29-42%。BMI> 40 kg/m2肥胖患者行THA容易并发髋臼位置不良和假体脱位，行TKA容易并发技术失误和MCL撕脱。BMI> 50 kg/m2的重度肥胖患者感染发生率是正常人群的20倍，其他并发症发生率>50%。也有部分研究认为前面的数据有点危言耸听，肥胖患者并没有那么可怕。总的来说，关节置换术对于肥胖患者甚至病态肥胖患者的临床疗效良好，术后患者功能改善、满意度高，但与正常人群相比，其临床疗效欠佳。

    For every 5-unit increase in BMI above 25 kg/m2, the overall risk of mortality in the general population increases by 30%122. Although dietary modification, drug therapy, behavioral changes, and exercise are effective in a highly motivated subset of individuals, these strategies are unsuccessful in most patients. Inability to exercise because of arthritis represents a logical reason for failure of weight-loss therapy, but morbidly obese patients often do not lose substantial weight even after total joint arthroplasty96. Preoperative weight loss should be recommended in morbidly obese patients and required in super-obese patients. Bariatric surgery is more effective than nonoperative therapy in patients with a BMI of >40 kg/m2 and typically results in a weight loss of 20 to 30 kg123,124. The overall mortality rate and adverse event rate associated with current bariatric procedures are <1% and approximately 20%, respectively123. However, there is conflicting evidence regarding whether bariatric surgery performed before or after total joint arthroplasty affects complication rates110,125. 

    当BMI＞25 kg/m2后，BMI每增加5 kg/m2，人群的死亡率增加30%。尽管医从性高的患者通过饮食控制、药物治疗、行为改变和积极的运动能有效减肥，但对于大部分患者这些措施是无效的。虽然很多关节炎患者以关节活动受限为由借口未进行减肥治疗，但是TJA后大部分患者仍未减肥成功提示该类患者无法坚持相关减肥治疗。对于肥胖患者术前应建议减肥，而对于重度肥胖患者必须先行减肥治疗再考虑手术。对于BMI＞40 kg/m2的患者，肥胖外科手术比非手术治疗更为有效，一般可有效减去20-30kg体重。目前肥胖外科手术死亡率低于1%，不良事件发生率约20%。但目前对于在TJA前后行肥胖外科手术是否会影响TJA相关并发症尚不明确。

    Obstructive sleep apnea is present in 5% to 11% of total joint arthroplasty patients126-128. This condition is associated with an increased prevalence of perioperative complications129 and a longer length of stay, but these can be reduced with adequate screening and management strategies126. The current gold standard for diagnosing obstructive sleep apnea is an overnight sleep study involving polysomnography130, but the STOP-BANG questionnaire (Table VIII) can screen for high risk patients129. Surgery can be delayed to definitively diagnose obstructive sleep apnea, or elective surgery can proceed with use of anesthetic and other perioperative measures to mitigate the effects of the presumptive obstructive sleep apnea126,129,131 

    约有5-11%的TJA患者合并阻塞性睡眠呼吸暂停，这部分患者围手术期并发症增多、住院时间延长，但经过合适的治疗能减少其发生率。目前诊断阻塞性睡眠呼吸暂停的金标准是整晚多频道睡眠记录，STOP-BANG调查表（表VIII）能鉴别出高风险患者。对于明确诊断的患者应推迟手术，或使用麻醉药物和其他方法缓解阻塞性睡眠呼吸暂停。

Hematologic Conditions

    Venous thromboembolic disease is one of the greatest risks associated with total joint arthroplasty. Historically, the rate of fatal pulmonary embolism has been reported to be up to 3.4%132. With improved thromboprophylaxis, the rates of fatal and symptomatic nonfatal pulmonary embolism have been reported to be 0.22%133 and 0.41%, respectively134. There is debate between the American College of Chest Physicians (ACCP) and the AAOS135-140 about the appropriate thromboprophylaxis protocol 141. Each patient is unique (Table IX), and the surgeon and internist should reach an agreement regarding prophylaxis. In high-risk patients who have contraindications to anticoagulation therapy142, failure of anticoagulation, cessation of anticoagulation therapy secondary to bleeding, or saddle emboli, inferior vena cava filters are effective in preventing pulmonary embolism (reducing the prevalence to 0% to 3.1%)143-146. However, such filters should not be used without careful consideration because they may not affect the overall mortality rate and they are associated with an increase in the rate of primary or recurrent deep venous thrombosis147-149. Many such filters are removable, but actual retrieval rates are low because of thrombosis and incorporation into the vessel wall143,150. Complications can occur in 11% of patients during retrieval143,144. Special considerations are necessary in patients on chronic anticoagulation therapy (Table X).

    静脉血栓栓塞症是TJA中危险度最高的并发症之一，致死性肺栓塞发生率为3.4%。随着抗凝治疗的改进，致死性肺栓塞和非致死性症状性肺栓塞发生率降至0.22%和0.41%。但目前ACCP和AAOS对如何抗凝尚存在争议，每一个病人都有其具体情况（表IX），外科医生和内科医生应根据其具体情况选择预防药物，对于有抗凝禁忌症、无法抗凝、因出血停止抗凝、已有血管栓子的高风险患者，下腔静脉过滤器能将肺栓塞的风险降至0-3.1%。但是安装过滤器必须有明确的指征，因为他们虽然能够预防肺栓塞，但并不能降低整体死亡率，同时会导致下肢深静脉血栓的发生和复发。尽管该类过滤器能够取出，但大部分患者由于血栓和血管壁耐受性差而选择终身留置，约有11%的患者在取出过滤器时会发生相应并发症。表X提示了下列慢性抗凝患者需要考虑的特殊问题。 

    Hemoglobin levels used to define anemia range from <13 to <14.2 g/dL in men and <11.6 to <12.3 g/dL in women151. Anemia is not uncommon in elderly patients152, and it is present in 21%of patients undergoing elective orthopaedic surgery153. Blood transfusion after total joint arthroplasty is associated with an increased infection rate. Patients with a preoperative hemoglobin level of <13 g/dL are 4 to 5.6 times more likely to require a transfusion than patients with a level of between 13 to 15 g/dL and fifteen timesmore likely than patientswith a level of >15 g/dL154,155. Preoperative autologous donation of blood can pose administrative difficulties, and such blood has a limited shelf-life and is wasted 25% to 46% of the time156-159. Patients without preoperative anemia did not benefit from autologous blood donation158, and patients who donated were less likely to receive allogeneic blood but overall they were more likely to receive a blood transfusion156. It is recommended that patients with a hemoglobin level of <11 g/dL undergo a work-up to identify the underlying cause of the anemia157. Patients with a below-normal hemoglobin level should receive multivitamins with iron supplementation to optimize their condition. Analyzed as a continuous variable rather than by category, the hemoglobin level is not a significant independent risk factor for myocardial infarction or death within the first thirty days after total joint arthroplasty160. 

    既往教材认为男性血色素低于14.2或13 g/dL，女性血色素低于12.3或11.6方能诊断贫血。但很多老年患者存在贫血，研究显示21%的骨科择期手术病人存在贫血。TJA术后输血可能导致感染率增高，对于术前血色素小于13 g/dL的患者较血色素在13-15 g/dL的患者术后需输血的可能性增加3-4.6倍，较血色素大于15 g/dL的患者术后需输血的可能性增加14倍.术前预存血保存困难、且有25-46%血缘会被浪费，因此管理较为困难。若患者术前无贫血往往不需预存血，预存血虽然可以减少异体输血，但会增加患者需要输血的可能性。血色素低于11 g/dL建议寻找贫血的可能病因，贫血患者应补充复方维生素和铁剂以改善贫血。由于变数众多，目前血色素水平并不是TJA术后30天内心肌梗塞和死亡的独立危险因素。 

    Hemophilia is associated with a 3% to 16% rate of infection after total joint arthroplasty161-163. Clotting factor infusions should be used to maintain clotting factor levels perioperatively. Although the literature regarding total joint arthroplasty in patients with hemophilic arthropathy is limited to medium-sized case series, results appear to be satisfactory, with elevated complications rates in some studies164-169 

    血友病患者TJA术后感染率为3-16%，围手术期应补充凝血因子保证正常凝血功能。中等样本量的文献显示TJA临床疗效满意，但并发症有所增高。

    Femoral head osteonecrosis affects up to 50% of patients with sickle-cell anemia170,171. The rate of complications during arthroplasty is as high as 67%, with the complications including sickle-cell-related events (acute chest syndrome or vaso-occlusive crisis, in 19%), transfusion issues (12%), and surgical complications (15%)171,172. Close monitoring of oxygenation, body temperature, fluid resuscitation, and acid-base balance is necessary to prevent sickle-cell-related events. Cardiomegaly and underlying congestive heart failure may accompany chronic anemia. A pain management specialist should help to manage patients with prior narcotic use. A hematologist should advise whether preoperative transfusion or plasmapheresis is indicated173. Patients with sickle cell anemia are often functionally asplenic and should be evaluated for latent niduses for infection170. 

    50%的股骨头坏死患者合并镰状细胞贫血，该类患者THA术后并发症发生率高达67%，其中镰状细胞贫血相关症状（急性胸痛、血管危象，19%）、输血反应（12%），手术相关并发症（15%）。严密观测氧饱和度、体温、液体量和酸碱平衡情况有利于预防镰状细胞贫血相关症状。慢性贫血常合并心脏扩大以及潜在的充血性心力衰竭。术前应请疼痛专家决定麻醉药品的使用，请血液科专家决定是否术前输血或血浆。镰状细胞贫血患者脾脏常无功能，应检查由于潜在的感染灶。

Age

    Increased age is associated with higher rates of medical complications and death after total joint arthroplasty8,13,14,28,174-176. Patients older than eighty-five years of age have a risk of in-hospital mortality that is more than ninefold greater than that of patients forty-five to sixty-four years of age7. The thirty-day mortality rate after total hip arthroplasty increases from 0.03% at <65 years of age to 0.07% at sixty-five to seventy-five years, 1.41% at seventy-five to eighty-five years, and 4.91% at more than eighty-five years13. Age alone, however, should not be a contraindication to surgery177. Forty percent of centenarians are functionally independent178. Although the overall mortality risk after total joint arthroplasty was 12% for patients who were more than 100 years old, the risk was similar to that of patients between ninety and 100 years old when adjusted for the overall mortality differences between the two groups11. Surgeons should carefully screen elderly patients and be prepared for higher rates of death and complications and a longer hospital stay. 

    TJA患者年龄越大，术后并发症和死亡的危险度也越大。85岁以上患者在院死亡率较45-65岁患者增加9倍以上。THA术后3天死亡率小于65岁患者中为0.03%，而在65-75岁患者中增加至0.07%，75-85岁患者中为1.41%，85岁以上人群为4.91%。尽管百岁以上老人TJA术后整体死亡率为12%，但其与90-110岁老人组相比无明显差异，因此年龄并不是手术的禁忌症。但外科医生应仔细评估患者，并做好术后死亡率、并发症发生率较高和住院时间延长的准备。

Renal Conditions

    Unlike coronary, cerebral, or peripheral vascular disease, renal ischemia is insidious in nature. Renal impairment is associated with a longer hospital stay, cardiac complications, early and late infections, and greater in-hospital and one-year mortality7,69,179,180. Postoperative acute renal failure, defined as a rise in serum creatinine to more than twice the baseline value or a urine output of <0.5 mL/kg-hr for twelve hours, occurs in 0.5% of total joint arthroplasty patients179 compared with 5% of the general hospitalized population181. Patients with renal insufficiency (serum creatinine > 1.5 mg/dL182 or creatinine clearance < 100 mL/min181) should be evaluated for potential treatment and preventative preoperative measures. 

    与心血管疾病和周围血管疾病不同，肾损害的临床症状不明显。肾功能不全常导致住院时间延长、心血管并发症、早期和晚期感染和住院死亡率、术后一年死亡率的增加。术后急性肾衰竭是指血肌酐高于标准值2倍或12小时内尿量<0.5 mL/kg-hr，其TJA术后发生率为0.5%，较住院总体人群5%低。肾功能不全患者（肌酐creatinine > 1.5 mg/dL或肌酐清除率< 100 mL/min）术前应仔细评估手术风险。

    Total joint arthroplasty in patients on dialysis has been examined in several case series. The mean duration of dialysis before surgery was six to twelve years. Function, reduction in pain, and the implant survival rate were satisfactory69,183-185. However, the rate of complications was high; a 66% rate of medical complications, a 21% rate of orthopaedic complications, and a 40% mortality at three years were reported in one study183. Another study demonstrated a 58% rate of early complications and mortality186. The reported overall prevalence of periprosthetic infection ranges from 0% to 19%69,184,185,187-191. Although dialysis is not an absolute contraindication to arthroplasty, patients need an in-depth medical evaluation and extensive risk counseling. 

    肾功能不全需透析患者行TJA已经有数个临床研究，一项研究针对平均透析时间为6-12年患者，术后功能、疼痛减轻程度、假体生存率均满意。但并发症发生率较高，内科并发症为66%，其中21%为骨科并发症，术后3年死亡率40%。另一项研究显示术后58%的早期并发症和死亡率。各项研究表明假体感染率在0-19%之间。综上所述，透析并不是关节置换的绝对并发症，但该类患者需要仔细的评估以及对各项风险做好充分准备。

Peripheral Vascular Conditions

    Vascular complications following total joint arthroplasty are rare (0.03% to 0.5%)192 but are usually limb-threatening or life-threatening193. Unpalpable peripheral pulses, intermittent claudication, pain at rest, arterial ulcers, substantial vascular calcifications, and a history of vascular insufficiency or vascular surgery should alert clinicians to at-risk patients192,194,195. If arterial insufficiency is suspected, an ankle-brachial pressure index (ABPI) should be ascertained, and referral to a vascular surgeon should be considered if the value is <0.9196. The timing of arterial reconstruction or bypass relative to total knee arthroplasty is controversial. Some authors recommend that vascular surgery precede total knee arthroplasty if the ABPI is <0.5 or if compromised peripheral blood supply is evident on Doppler ultrasonography197,198. Total knee arthroplasty with tourniquet use (300 mm Hg) does not appear to exacerbate preexisting atherosclerotic disease in the presence of noncritical ischemia of the leg or to impair the arterial supply at six weeks postoperatively199. 

    TJA术后血管并发症并不常见，约0.03-0.5%，但一旦发生常威胁肢体和生命。远端肢体无脉、间歇性跛行、休息痛、动脉溃疡、血管钙化以及既往有血管功能不全或血管手术史均提示该病人为高危患者。一旦考虑动脉功能不足，应测量踝-臂血压压力指数(ABPI)，若测量值<0.9196应转诊血管外科医生处理。何时考虑血管重建或分流术尚存在争议，若ABPI<0.5或血管彩超证实周围血管功能不全，应在TKA术前此类操作。TKA术中使用300mmHg止血带并不会增加轻中度患者先前存在的动脉粥样硬化，术后六周也没有损害动脉血液供应。

Patients with prior peripheral vascular bypass or angioplasty should be assessed by a vascular surgeon192. Atourniquet should not be used192,197. Small doses of intraoperative heparin (2500 U) and a preoperative screening ultrasonogram followed by an angiogram to identify occult stenosis or occlusions may be necessary200. A vascular examination may be necessary immediately preoperatively to confirm vascular patency in at-risk patients196. 

对于有周围血管分流术或血管重建术病史的患者，不建议使用止血带。术中使用小剂量肝素(2500 U)，术前血管彩超明确血管狭窄或闭塞部位将会带来益处。总之，对于高危患者术前应行血管相关方面检查以明确血管功能。

Infection

    Periprosthetic infection occurs within the first two years after 0.25% of total hip arthroplasties and 2.0% of total knee arthroplasties, and such infections are associated with a mortality rate of 2.7% to 18%102,201,202. Nineteen percent of all periprosthetic infections occur within the first ninety days, and 59% occur within the first two years58. Surgical site infections are associated with a 60% greater risk of intensive-care unit stay, a fivefold greater risk of hospital readmission, and a fivefold to eleven fold greater risk of death203. The prevalence of infection after total joint arthroplasty increased nearly twofold from 1990 to 20041, likely because of improved medical care, wider availability of total joint arthroplasty for less healthy patients 204,205, and emergence of more virulent antibiotic-resistant microorganisms. Patient risk factors for infection include posttraumatic arthritis, prior surgery, chronic liver disease, corticosteroid use, alcohol or intravenous drug abuse, greater severity of comorbidities, malnutrition, anemia, obesity, and diabetes 

    THA和TKA术后2年感染率为0.25%和2%，感染后死亡率为2.7-18%。19%的感染发生于术后90天内，59%发生于术后2年内。术后一旦感染入住ICU可能性增加60%，再入院率增加5倍，死亡率增加5-11倍。从1990到2004年，TJA感染率增加了近2倍，原因可能与医疗护理改善导致更多健康状况不良的患者接受了TJA以及更多耐药菌的出现有关。感染的高危因素包括创伤性关节炎、既往手术史、慢性肝脏疾病、糖皮质激素使用史、酗酒或反复静脉用药者、严重的内科疾病、营养不良、贫血、肥胖和糖尿病。

    In addition to preoperative patient optimization (e.g., glucose control and nutritional supplementation), preparations such as surgical site shaving on the day of surgery, intraoperative measures such as skin decontamination, and screening and treatment of methicillin-resistant Staphylococcus aureus (MRSA) have been shown to be effective in reducing infection207,208. Twenty-three percent of patients undergoing elective orthopaedic surgery are carriers of Staphylococcus aureus, and 5% are carriers of MRSA209. The risk of developing a surgical site infection is sevenfold greater in carriers of MRSA compared with methicillin sensitive Staphylococcus aureus (MSSA), and most surgical site infections are attributable to community-acquired strains brought into the hospital by the patient209. With increasing use of vancomycin for MRSA, vancomycin-resistant enterococcal infections have been reported in arthroplasty patients210. The association between perioperative urinary tract infection and periprosthetic infection appears to be minimal211-213 despite several case reports describing hematogenous seeding and delayed infection214. The classic urinary tract infection symptoms of dysuria and urgency and increased frequency of urination are often absent in elderly patients, and approximately 4% of total joint arthroplasty patients have asymptomatic urinary tract infections prior to surgery212. A rational approach to preoperative urinary tract infection based on available studies is outlined in Table XI. Short-term use of indwelling catheters is superior to intermittent straight catheterization and reduces urinary retention and bladder distention without increasing the rate of urinary tract infection215,216. Urinary catheters should be removed as soon as possible217,218. Patients with preoperative obstructive symptoms or bladder outflow problems should see a urologist.

    除了术前改善病人基本情况（如控制血糖、增加营养），手术前夜手术部位剃毛、术中严格的皮肤准备、预防MRSA感染都能有效降低感染率。23%的择期骨科手术患者携带金黄色葡萄球菌，5%携带MRSA。MRSA携带者比MSSA携带者手术部位感染率高7倍。大部分病原菌均为社区获得菌。随着万古霉素广泛应用于治疗MRSA，已有TJA术后耐万古霉素肠球菌感染的报道。尽管有很多血源性播散和延期感染的报道，但目前认为围手术期尿路感染与假体感染并无直接联系。老年病人往往没有尿频、尿急、尿痛这些典型的尿路感染症状，约4%TJA患者手术前有非典型尿路感染。表XI为术前尿路感染的治疗指南。在减少尿储留和膀胱过度充盈方面，短期留置导尿管比反复一次性导尿要更为合适，也不会增加尿路感染的发生率，当然，一旦条件允许，应尽早拔除留置导尿管。对于存在尿路梗阻症状和膀胱出口梗阻的患者应请泌尿外科医生行相应处理。 

    Revision arthroplasty is well known to be associatedwith an elevated risk of infection compared with primary arthroplasty219. Performing a primary total joint arthroplasty for posttraumatic arthritis in a patient with a history of septic arthritis is even more hazardous. Precautionary measures include joint aspiration, analysis of the serum C-reactive protein level and erythrocyte sedimentation rate, and multiple intraoperative cultures, plus indium-labeled leukocyte scans in select cases220. Primary total joint arthroplasty should be delayed for at least one year after resolution of a known infection; if the levels of any of the inflammatory markers indicate ongoing infection, the arthroplasty should be further delayed until normalization of these indices. Patients with a prior fracture221 and/or local infection should be extensively screened and counseled prior to surgery. 

    关节翻修术与初次置换相比感染率增高。对有化脓性关节炎病史的患者行初次关节置换术也有很大的风险。对于此类患者应进行无菌关节穿刺筛查有无感染、仔细分析CRP、ESR水平，术中进行多点组织细菌培养，必要时采用铟标记的白细胞扫描。初次关节置换应在已知感染控制后一年进行，如果有任何炎性标记物提示感染仍在持续，关节置换术应无限期推迟直到达到指征。总之，对于既往有骨折手术史和局部感染史的患者应仔细筛查，手术应慎之又慎。

    Corticosteroid injections are often used with local anesthetics for conservative management of osteoarthritis. Although there is no conclusive evidence, corticosteroid injections may predispose patients to septic arthritis after total joint arthroplasty 222,223. Most orthopaedists prefer to delay total joint arthroplasty until two to three months after corticosteroid injection. 

    局部注射糖皮质激素以改善OA的局部疼痛症状。尽管目前没有结论，但很多研究认为糖皮质激素注射史是TJA术后感染的危险因素。因此建议在糖皮质激素注射后2、3月再考虑行TJA。

Pulmonary Conditions and Smoking

    Acute hypoxic episodes (peripheral oxygen saturation [SpO2], 65%to 89%) occur in 4%of total joint arthroplasty patients during hospitalization. Although most of these episodes are due to atelectasis or unknown causes, some are secondary to important lung conditions including pneumonia, pulmonary edema, bronchospasm, and exacerbation of chronic lung disease 224. Pulmonary complications are strongly associated with comorbidities that are clinically identifiable, and there is no consensus regarding whether preoperative testing such as spirometry or arterial blood gas analysis is routinely necessary176,225. 

    约4%TJA患者在住院期间会发生急性缺氧综合症（外周SpO265-89%）。尽管大部分是由于肺不张或其他未知原因，也有部分是由于肺炎、肺部水肿、支气管痉挛和慢性肺部疾患恶化所造成。肺部情况在临床上较容易诊断，但术前肺功能测试和动脉血气是否必须目前尚存在争议。

    Elective total joint arthroplasty should be delayed in patients experiencing acute exacerbation of chronic obstructive pulmonary disease (COPD). The relative risk of complications for patients with COPD ranges from 2.7 to 4.7226-228, and COPD should be treated aggressively with standard measures (bronchodilators, therapy, corticosteroids, and/or smoking cessation) before the arthroplasty to achieve optimum exercise capacity and maximum symptom reduction225. If sputum or bronchial veolar fluid suggest infection, the surgery should be postponed and antibiotics should be administered229. 

    对于COPD患者急性发作时应推迟TJA，COPD患者并发症的相对危险度为2.7-4.7，因此术前应积极按照标准（支气管扩张剂、糖皮质激素和禁烟）治疗COPD以改善肺功能。若痰或支气管分泌物培养提示感染，应推迟TJA并给予抗生素。

    The prevalence of perioperative bronchospasmin patients with asthma is 1.7%230. To minimize complications, patients should be free of wheezing and have a peak flow that is >80% of the predicted value or the personal best value231. A short course of perioperative oral corticosteroids to treat asthma does not increase the risk of infection or complications232,233. Inhaled beta-2 adrenergic agonists and anticholinergic agents should be administered until the day of surgery in symptomatic asthmatics234. The effect of viral upper respiratory infection prior to surgery on pulmonary events is unknown, but it is reasonable to delay surgery in severe cases225 

    约有1.7%哮喘病人围手术期发生支气管痉挛，为使并发症发生率降至最低，患者应远离哮喘源，肺功能预测峰值应>80%或出于个人最佳情况。围手术期短期使用糖皮质激素治疗哮喘并不会增加感染和并发症的发生率。对于有症状的哮喘患者，手术当天应吸入beta-2受体阻滞剂以及静脉给予抗副交感神经药物。对于病毒性上呼吸道感染患者如何处理尚不明确，但大部分医生都会选择推迟手术。

    Pulmonary hypertension is rare (0.4%) after total joint arthroplasty235,236. It is associated with a fourfold increase in mortality (2.4% compared with 0.6% for total hip arthroplasty and 0.9% compared with 0.2% for total knee arthroplasty). Primary pulmonary hypertension is associated with the greatest risk of mortality (5%) and warrants preoperative consultation with a pulmonologist235,236 

    TJA术后肺动脉高压罕见，约0.4%，一旦发生患者死亡率提高4倍（THA为2.4%VS0.6%，TKA为0.9%VS0.2%）。初次肺动脉高压死亡率最高，约5%，此时应请呼吸科专家诊治。

    The detrimental effects of smoking on the immune system 237 and on oxygen delivery to healing tissues238 are well known. Infection, hematoma, and wound complication rates are significantly lower in patients who cease smoking at least six to eight weeks prior to total joint arthroplasty compared with persistent smokers239-241.Whether those benefits are evident for patients who do not quit until one to three weeks preoperatively is controversial 240-243. Intense intervention consisting of nicotine replacement therapy and one-on-one sessions with a professional counselor is effective. However, less-involved measures such as counseling alone, pharmacotherapy alone, or a combination of pharmacotherapy with short-term counseling only two to three weeks before surgery, informal counseling sessions, or written instructions are not240,244. There is no evidence that nicotine replacement therapy has an adverse effect on wound-healing240. Surgery is a motivational opportunity for patients to quit the highly addictive habit245. On average, preoperative smoking cessation is associated with a 41% relative reduction in the risk of postoperative complications, and the reduction is 19% for each week of cessation 

    吸烟对免疫系统和伤口的氧和供应有明显的损伤。TJA术前戒烟6-8周患者与持续吸烟患者相比，术后感染、血肿形成和伤口并发症的发生率均显著降低。术前戒烟1-3周是否有效目前尚存在争议。同时进行尼古丁替代治疗和一对一的专业医生咨询的这种强力组合治疗方式对于戒烟是有效的，但其他如单纯专业医生咨询、单独使用药物、术前2-3周的短期用药加上医生咨询、非专业医生咨询或者书面指示则效果不佳。目前无证据认为尼古丁替代治疗会对伤口愈合产生不良反应。手术是患者戒烟的一个极好机会。总得来说，术前戒烟能把术后并发症的相对危险度降低41%，早戒烟一周相对危险度降低19%。

Hepatic Conditions and Malnutrition

    Hepatic failure results in an impairment of neutrophil function and a reduction in the removal capacity of the reticuloendothelial system247,248.Mean survival for patients who develop cirrhosis after a prior major complication such as ascites, jaundice, encephalopathy, or variceal bleeding is 1.6 years249. Twenty-six complications were reported after total knee arthroplasty in a study of sixty patients with Child class-A cirrhosis (bilirubin < 1.5 mg/dL, albumin > 3.5 g/dL, prothrombin time < 4 sec prolonged, no encephalopathy, no ascites249) due to alcoholism or hepatitis250. Blood loss was elevated despite precautions, and infection occurred in 21% of the patients. Older age, a low platelet count, and hepatitis-B-related cirrhosis were independent risk factors for infection. A history of hepatic decompensation and a history of variceal bleeding were predictors of complications, and hepatoma was a predictor of mortality250. Another study indicated that emergency total hip arthroplasty for hip fractures in Child class-A or B patients resulted in high rates of complications and death, whereas only two major and four minor complications occurred after elective total joint arthroplasty in twenty-five patients251. Total joint arthroplasty is not advised for patients with cirrhosis if they have a history of hepatic decompensation or variceal bleeding, or if the cirrhosis is Child class C or possibly class B.

    肝功能衰竭将损害中性粒细胞功能以及降低网状内皮系统排除能力。对于进行性肝硬化患者，一旦发生如腹水、黄疸、肝性脑病、静脉曲张破裂出血等主要并发症，其平均寿命只有1.6年。研究显示对于60例酒精性肝硬化Child A级患者（胆红素< 1.5 mg/dL，白蛋白> 3.5 g/dL，前凝血酶原时间< 4 sec，无肝性脑病，无腹水）行TKA置换，围手术期有26次相关并发症的发生。即使有相应预防措施，失血量也会增加，感染率为21%。年龄、血小板计数低、乙型肝炎相关肝硬化是感染的独立危险因素。有肝功能不全病史以及静脉曲张破裂出血高度提示术后相关并发症增多，而肝癌高度提示术后死亡率增高。另一项研究显示，因髋部骨折急诊行THA的Child A或B级肝病患者，术后并发症和死亡率均较高，若改行择期手术，仅有2个主要和4个次要并发症。总之，对于有肝功能不全或静脉曲张破裂出血病史的患者，或者肝硬化分级为C级，甚至B级患者，不建议行TJA。

    Malnutrition is associated with longer hospital stays252, infection253, and a fivefold to sevenfold greater risk of developing major wound complications after total joint arthroplasty254,255. Occult malnutrition in healthy patients and paradoxical malnutrition in obese patients are not uncommon. Nutritional deficiency should be screened for in at-risk patients with cachexia, morbid obesity, malignancy, or a history of wound healing issues or alcoholism201. Laboratory values that have been reported to be predictive of significantly increased complications vary252,253,256,257, but diagnostic levels are described in Table XII. Malnourished patients should be referred to a nutritionist for optimization. 

    营养不良患者TJA术后住院时间延长、感染率增加、主要伤口并发症增加至平时的5-7倍。健康人群中不明原因的营养不良和肥胖人群中的病态营养不良患者均不少见。对于合并恶病质、病态肥胖、恶性肿瘤、伤口愈合不良史和酗酒者应检查营养情况。实验室诊断营养不良的指标众多，标准见表XII。对于英语不良患者术前应请营养师改善其营养情况。

Diabetes

糖尿病

    Diabetes mellitus affects 8% to 10% of patients undergoing total joint arthroplasty258,259, and 25% of diabetics are unaware that they have this condition260. The risks of major, minor, local, and systemic complications are all elevated postoperatively and during hospitalization31,102,261-265. Preadmission hyperglycemia has been shown to be an independent risk factor for in hospital symptomatic pulmonary embolism266. Surgery on patients with poorly controlled blood glucose levels should be delayed until hemoglobin A1C levels are satisfactory and a proper pharmacological regimen is established. The American Diabetes Association and the American Association of Clinical Endocrinologists recommend a target hemoglobin A1C level of <7.0%; for hospitalized patients who are not critically ill, they recommend a blood glucose level of <140 mg/dL before meals and a random blood glucose level of <180 mg/dL267. Patients with uncontrolled diabetes mellitus had higher odds of stroke, urinary tract infection, ileus, postoperative hemorrhage, wound infections, and death compared with patients with controlled diabetes258. Type-I and type-II diabetics have similarly elevated risks compared with nondiabetics258,268. Surgery should be scheduled for early in the day, and a basal-bolus rather than a sliding-scale insulin regimen should be used261.

THA

    患者中约有8-10%罹患糖尿病，约25%患者并不清楚他罹患此病。糖尿病患者术后和住院期间主要、次要、局部和系统并发症发生率全面升高。血糖增高是住院期间肺栓塞发生的独立危险因素。对于血糖控制不佳的患者应延迟手术直到血红蛋白A1C达到满意值。美国糖尿病协会和美国临床内分泌学家协会推荐对于病情不重的患者将血红蛋白A1C降至7%以下，餐前血糖降至140 mg/dL以下 ，随机血糖降至180 mg/dL以下 。未控制好血糖的糖尿病患者术后中风、尿路感染、肠梗阻、出血、伤后感染和死亡率均增高。I型糖尿病和II型糖尿病在相关并发症风险中无明显差异。对于糖尿病患者TJA应在上午进行，推荐基础用药+餐前大剂量使用胰岛素而不是待血糖升高再用胰岛素。 

    Risk stratification and appropriate preoperative management of comorbidities will decrease adverse events after total joint arthroplasty. Impending modifications to existing reimbursement plans in the United States include financial incentives that will pressure hospitals to adopt evidence-based algorithms and optimize patient safety. Nevertheless, although 90% of complications occur within four days of surgery, fewer than 50% of patients with life-threatening complications have identifiable predisposing factors. Orthopaedists must remain vigilant and select total joint arthroplasty candidates prudently to minimize adverse events whenever possible 

    围手术期风险控制和术前对合并症的恰当处理能够有效的降低TJA术后并发症。目前美国即将进行的医疗改革包括奖励医院采用询证医学支持的医疗措施来保证患者的安全。无论如何，尽管有90%的并发症发生在术后4天，但仅有不到50%发生威胁生命并发症的患者能找到明确的危险因素。因此骨科医生应该谨慎的选择手术以保证病人的安全。