Vol 10, No 3, May/June 2002 217 Disabling hip pain requiring total hip arthroplasty (THA) can have a variety of etiologies, many of which have an incidence of bilaterality. Bilateral hip disease can be caused by a single disorder or by a combi- nation of two discrete processes. Primary osteoarthritis (OA) of the hip, the most common disorder associated with severe hip pain and disability in the elderly, has a preva- lence of 3.1% and occurs bilaterally in 42% of patients. 1 Rheumatoid arthritis of the hip, although less common with an incidence of at least 0.2 per 1,000 per year, affects hips bilaterally in greater than 50% of patients. In a review of bilateral THAs done as a single stage, the diagnosis was OA in 140 of 244 hips (57%) and rheumatoid arthritis in 42 of 244 hips (17%). 2 Other etiologies of hip disease include secondary OA (eg, secondary to trauma, osteo- necrosis, developmental dysplasia of the hip, Legg-Calvé-Perthes dis- ease, or slipped capital femoral epi- physis), inflammatory processes (eg, psoriatic arthritis, ankylosing spon- dylitis, or Crohn’s disease), and metabolic processes (eg, Gaucher’s disease, Paget’s disease, ochronosis, or hemochromatosis). Development of the Single-Stage Bilateral Approach Lipscomb 3 in 1965 reviewed a series of 349 patients who had undergone simultaneous reconstructive sur- gery (such as osteotomies) for bilat- eral hip disease, but single-stage bilateral THA was initially reported by Charnley in 1967. 4 Jaffe and Charnley 5 in 1971 published a re- view of 50 consecutive patients in whom Charnley had done bilateral low-friction arthroplasty. There were an equal number of men and women; average age was 61.4 years (range, 47 to 74 years). Eighty per- cent had primary or secondary OA; the remainder of the patients had hip disorders resulting from inflam- matory causes. Jaffe and Charnley concluded that the minimal addi- tional risk of complications with bilateral compared with unilateral low-friction arthroplasty was offset by the advantages of one-time administration of anesthesia, a sin- gle recuperative period, and an overall decreased length of stay. The minimal increase in risk was largely attributable to the experi- enced efficiency of the surgical team, which did approximately 1,000 hip procedures per year. Dr. Macaulay is Director, Center for Hip and Knee Replacement, Columbia University, New York, NY. Dr. Salvati is Director, Hip and Knee Service, Hospital for Special Surgery, New York. Dr. Sculco is Chief, Department of Orthopaedic Surgery, Hospital for Special Surgery. Dr. Pellicci is Attending Orthopaedic Surgeon, Hospital for Special Surgery. Reprint requests: Dr. Macaulay, Rm 1146, PH 11th Floor, 622 West 168th Street, New York, NY 10032. Copyright 2002 by the American Academy of Orthopaedic Surgeons. Abstract The number of single-stage bilateral total hip arthroplasties done each year is increasing. The risk of postoperative complications in medically stable patients is acceptable; complications are approximately 1.3 times more frequent than with unilateral total hip arthroplasty. Although there are no absolute indications for a single-stage bilateral total hip arthroplasty, the procedure is usually contraindicat- ed in patients with such comorbidities as heart disease, pulmonary insufficiency, or diabetes, and it is absolutely contraindicated in patients with a documented patent ductus arteriosus or septal defect. The primary postoperative concern is that the cardiopulmonary insult associated with two surgical wounds and sur- geries can lead to an increase in thromboembolic events. The cost for single-stage bilateral total arthroplasty is less than that for a two-stage bilateral total hip arthroplasty, with savings predominantly due to reduced length of acute hospital stay. However, the decision to undergo single-stage bilateral total hip arthroplasty is one that must be made in concert with the patient. J Am Acad Orthop Surg 2002;10:217-221 Single-Stage Bilateral Total Hip Arthroplasty William Macaulay, MD, Eduardo A. Salvati, MD, Thomas P. Sculco, MD, and Paul M. Pellicci, MD Single-stage bilateral THA has gained popularity at some institu- tions in North America. In the past three decades, 976 patients (1,952 hips) have undergone single-stage bilateral THA at the Hospital for Special Surgery in New York. This number represents 7% of the more than 27,000 THAs performed at that institution during that time. From 1970 to 1985, 325 single-stage bilat- eral THAs (650 hips), approximately 20 per year, were done. 6 The rate now has increased to more than 70 bilateral procedures per year. In 1976, Ritter and Randolph 7 compared 50 patients who had bilat- eral total hip replacement with 50 patients who had 50 unilateral pro- cedures. They concluded that bilat- eral THA was feasible, carrying an only slightly increased risk of com- plications compared with unilateral THA. Table 1 summarizes the post- operative complications from this study. Ritter et al 8-10 reassessed bi- lateral THA in three subsequent arti- cles and reached similar conclusions. Salvati et al 2 reviewed three groups of bilateral THAs done at the Hospital for Special Surgery from 1970 to 1976. Group I (122 pa- tients, 244 hips) consisted of single- stage procedures, group II (134 patients, 268 hips) of bilateral THAs done during the same admission, and group III (205 patients, 410 hips) of bilateral THAs done during separate admissions. The authors noted the marked reduction in cost associated with less time in surgery and decreased length of hospitaliza- tion. They did not find a higher complication rate within any partic- ular group, despite the fact that Ritter and Randolph 7 previously had shown an increased rate of both phlebitis and myositis ossificans. Bracy and Wroblewski 11 reported on a series of bilateral THAs as a single-stage procedure done at the Centre for Hip Surgery (Wrighting- ton Hospital, Appley Bridge, UK). The average age of the 400 patients studied (237 women, 163 men) was 57.7 years. Seventy-five percent of the patients had primary OA. The authors concluded that this proce- dure could be done without higher risk of complication compared with the unilateral procedure, except for the incidence of fatal pulmonary embolism, which was 1.5% com- pared with 1.0% for unilateral THAs. However, the risk was still lower than if the patient had been exposed to two separate proce- dures. In a prospective study of periop- erative morbidity, Cammisa et al 6 compared 23 patients who had sin- gle-stage bilateral THA with 12 patients who had unilateral THA. They concluded that perioperative morbidity of single-stage bilateral THA was no greater than that with unilateral THA with regard to car- diopulmonary function and overall clinical outcome. Eggli et al 12 reported on bilateral THA done in 510 patients. Group A (128 patients) underwent single- stage bilateral THA, group B (126 patients) had the surgeries separat- ed by less than 6 weeks, and group C (256 patients) had both stages of the bilateral THA done between 6 weeks and 6 months apart. All patients had a minimum 1.5-year follow-up. The patients in group A showed no increased risk of compli- cation. Of the 4,000 THAs done between 1989 and 1995 at the Nuffield Orthopaedic Centre in Oxford, UK, 190 (4.75%) were part of a single- stage bilateral procedure. A retro- spective comparison of the compli- cations in this group with those of a group of 107 patients (214 hips) who had staged bilateral THA (with a 2- to 24-month interval between stages) showed that single-stage bilateral THA was as safe as the staged procedure. 13 In another study of 79 patients who had single- stage bilateral THA, the authors concluded that this procedure is Single-Stage Bilateral Total Hip Arthroplasty Journal of the American Academy of Orthopaedic Surgeons 218 Table 1 Complications After Total Hip Arthroplasty Total Hip Arthroplasty Postoperative Complications Unilateral Bilateral (50 patients) (50 patients) Phlebitis 1 patient 6 patients Myositis ossificans None 5 patients (8 hips) Pulmonary embolus 1 patient 3 patients Dislocation 2 patients 3 patients (3 hips) Urinary tract infecton None 3 patients Death 1 patient* 1 patient* Sacral decubiti None 1 patient Nonunion of greater trochanter None 1 hip Heel sores None 3 patients (3 bilateral) Wound hematoma 1 patient 4 patients (1 bilateral) Femoral artery embolus None 1 hip Fusion None 1 hip (secondary to myositis ossificans) Pneumonia None 1 patient Wound infection None None * Secondary to pulmonary embolism. (Adapted with permission. 7 ) appropriate for severe bilateral hip disease in selected patients. 14 Indications There are no absolute indications for a single-stage bilateral THA compared with staged procedures. The strongest indication is severe disabling bilateral arthritis of the hip in a medically fit patient. A rel- ative indication is the existence of a condition that may impede the rehabilitation process. For instance, a contralateral contracture might cause a suboptimal result, such as persistent hip flexion contracture on the treated side because of the patient’s inability to stand erect dur- ing ambulation. Contralateral hip pain may impede rehabilitation. An equivalent level of symptoms in both hips can make the decision as to which side to treat first more dif- ficult. (We do the most severely arthritic side first.) Another relative indication for single-stage bilateral THA is when lengthening during the hip reconstruction on the more symptomatic side would create an unacceptable limb-length inequality. Patient preference is important. Patients who desire a single period of anesthesia, hospitalization, and recovery are more amenable to hav- ing both hips done simultaneously. The surgeon, medical consultant, and anesthesiologist must agree that the patient is healthy enough to un- dergo the operation. The procedure should be done by an experienced team to assure expeditious surgery. In addition, familiarity by nursing and support staff with patients who have undergone single-stage bilat- eral THA can help avoid complica- tions in the perioperative period. Contraindications An elderly patient with significant comorbidities (eg, heart disease, pulmonary insufficiency, or dia- betes) usually is not a candidate for single-stage bilateral THA. Patients with a history of documented fat emboli syndrome, adult respiratory distress syndrome, pulmonary embolus, or myocardial infarction also are not optimal candidates. The existence of a documented patent ductus arteriosus or septal defect, which would allow access of embolized material, such as fat droplets, to the arterial system and thus directly to the brain and other vital organs, 15 is one of the few absolute contraindications to single- stage bilateral THA. The insult is increased with two procedures done in 1 day when compared with procedures done on different days. Surgical Protocol Bilateral THA is often performed on a hip table with the patient in the lateral decubitus position, with all bony prominences well padded and an axillary roll placed appropriately. The down leg may be equipped with mechanical compression. The operation takes place in a laminar flow enclosure with self-adherent plastic drapes. The surgical team, including the scrub technician, wear isolator suits to minimize the shed- ding of bacteria into the surgical wound. Anesthesia personnel re- main outside the enclosure, and room traffic outside the enclosure is kept to a minimum. Intravenous antibiotics are administered 15 min- utes before each incision (so that the total does not represent an overdose for the time period) and postopera- tively in all patients for 24 hours. Arterial lines, Foley catheters, and Swan-Ganz catheters are used in most cases. The Swan-Ganz cath- eters are important in deciding whether to proceed with the second hip. A decision not to proceed with the second hip may be made in approximately 5% of patients. This decision usually is based on elevated pulmonary artery pressure mea- surements, either at the start of the first hip or as manifested by a rise in the pulmonary artery pressure >30% after the first hip is completed. An indwelling epidural catheter is used for hypotensive epidural anesthesia (which allows for the administra- tion of more anesthesia and for postoperative patient-controlled analgesia). A posterolateral approach to both hips is utilized, with subsequent for- mal repair of the posterior capsule and external rotator muscles (includ- ing the quadratus femoris). The implants used are surgeon depen- dent. Two drainage tubes connected to a reinfusion system are inserted for all wounds and removed on postoperative day 1. The contents of the femoral canal are carefully suc- tioned before any instrumentation, and after placement of the cement restrictor the canal is lavaged, suc- tioned, and dried to further reduce the possibility of fat embolus. The patient is turned immediately after the first surgical hip wound is cov- ered with a sterile bandage. The sec- ond incision typically is made 20 minutes after application of the ster- ile dressing to the first hip. Routine use of intraoperative radiographs is not recommended; a postoperative portable anteroposterior radiograph of the pelvis will confirm the satis- factory position of both hips. Management of blood loss is important for both unilateral and single-stage bilateral THA. Expedi- tious surgery and hypotensive epidural anesthesia often can keep the total blood loss for the combined procedure to <350 mL. In the ab- sence of factors that may suggest the possibility of increased blood loss (eg, morbid obesity, fusion takedown, coagulopathy), the sur- geon should consider a protocol slightly more aggressive than that used for primary unilateral THA (ie, autodonation of two units preopera- William Macaulay, MD, et al Vol 10, No 3, May/June 2002 219 tively, preoperative administration of erythropoietin, hemodilution, or perioperative salvage). If there are complicating factors, consideration should be given to using combina- tions of techniques, such as intraop- erative cell salvage or recombinant human erythropoietin, or possibly foregoing a single-stage bilateral procedure. Most patients are monitored in the recovery room until the morning after surgery. Whenever possible, physical therapy begins on postop- erative day 1. Patients who can ambulate should bear weight as tol- erated with a walker. For patients with bilateral cementless femoral implants, Lofstrand crutches and four-point gait training are recom- mended in physical therapy. Most patients ambulate by postoperative day 2 and, on average, have a 6-day length of stay. A rehabilitative hos- pital stay of 7 to 10 days often occurs after hospital discharge. Complications The primary concern associated with single-stage bilateral THA is the additional cardiopulmonary insult associated with embolization of the contents of two femoral canals (particularly with cement pressur- ization) on the same day. The addi- tional impact on the three arms of Virchow’s triad (stasis, hypercoagu- lability, and intimal injury) associ- ated with the added surgical insult of two wounds and operations can lead to an increase in postoperative thromboembolic events. The phenomenon of fat embolism during THA was recognized quite early during the history of THA in the United States. Herndon et al 16 characterized the problem by doing femoral vein ultrasound and triglyc- eride analysis of femoral vein blood samples at various stages of the THA procedure in a series of 34 pa- tients. Some fat embolism occurred during the acetabular component seating, but the greatest insult oc- curred during femoral component insertion. None of the 34 patients studied had exhibited signs and symptoms of fat emboli syndrome. Similar information was obtained from a canine animal model of THA that same year. 17 These data indi- cate that the patient who exhibits clinical symptoms of fat emboli syn- drome after THA either has received a larger embolic load or, for some poorly understood physiologic rea- son, has pulmonary vasculature that does not handle the load as well as does that of other patients. The patient undergoing bilateral THA therefore is theoretically at greater risk for this complication. Fat emboli are believed to reach the systemic circulation either directly across the pulmonary capillary bed or indirect- ly via shunts (eg, a patent ductus arteriosus). In this way, embolic con- tent can get directly to vital organs, such as the brain or the myocardium. In 1979, Charnley 18 reported that the incidence of fatal pulmonary embolism for the first 7,959 low-fric- tion arthroplasties was 1.04%, while incidence of nonfatal pulmonary embolism was 7.89%. The incidence of fatal pulmonary embolism after bilateral low-friction arthroplasty was 1.65%, and the incidence of non- fatal pulmonary embolism was 12.8%. This incidence appeared to be an improvement if a doubled pul- monary embolism rate is assumed for single-stage bilateral low-friction arthroplasties (2 × 1.04 = 2.08% and 2 × 7.89 = 15.78%). Using intraopera- tive monitoring of pulmonary artery pressure, decreasing periods of femoral vein kinking, and avoiding mechanical compression may de- crease the rates of these adverse events. Many of the complications listed in Table 1 have not occurred with a frequency double that for unilateral THA. Dislocation rates remain <0.3% 19 when bilateral procedures are done, although this may be the result of patient selection bias. Cost Considerations The cost of single-stage bilateral THA is considerably less than that of two-stage bilateral THA. In one study, 12 the total length of hospital stay was 5 to 6 days less in the sin- gle-stage group, which accounted for a 30% reduction in overall cost. Two other studies have shown a 25% cost savings in the single-stage setting compared with doing two unilateral THAs. 20,21 The savings in both stud- ies was primarily attributed to length of hospital stay. In addition, the eco- nomic impact of lost employment productivity with two recuperative periods, although difficult to mea- sure accurately, is likely reduced with single-stage THA. Summary Single-stage bilateral THA is a viable option for the motivated patient with few comorbid conditions. The potentially higher risk of complica- tions does not necessarily reach the incidence expected when the THAs are performed in two stages. Com- plications as a result of single-stage bilateral THA may be reduced fur- ther when the surgery is done at a dedicated institution with an effi- cient surgical team and competent anesthesiologist. The total costs associated with single-stage bilateral total hip arthroplasty are less than those for two sequential arthroplas- ties because of the single surgical session, decreased anesthesia time, and shorter overall hospital stay and recuperative period. However, any savings are of secondary importance to the patient’s well-being, and the decision for single-stage bilateral total hip arthroplasty must be made by the patient, surgeon, medical consultant, and anesthesiologist. Single-Stage Bilateral Total Hip Arthroplasty Journal of the American Academy of Orthopaedic Surgeons 220 References 1. Tepper S, Hochberg MC: Factors asso- ciated with hip osteoarthritis: Data from the First National Health and Nutrition Examination Survey (NHANES-I). Am J Epidemiol 1993;137:1081-1088. 2. 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Lorenze M, Huo MH, Zatorski LE, Keggi KJ: A comparison of the cost effectiveness of one-stage versus two- stage bilateral total hip replacement. Orthopedics 1998;21:1249-1252. 21. Reuben JD, Meyers SJ, Cox DD, Elliott M, Watson M, Shim SD: Cost compari- son between bilateral simultaneous, staged, and unilateral total joint arth- roplasty. J Arthroplasty 1998;13:172-179. William Macaulay, MD, et al Vol 10, No 3, May/June 2002 221 . a history of documented fat emboli syndrome, adult respiratory distress syndrome, pulmonary embolus, or myocardial infarction also are not optimal candidates. The existence of a documented patent. disease, pulmonary insufficiency, or diabetes, and it is absolutely contraindicated in patients with a documented patent ductus arteriosus or septal defect. The primary postoperative concern is that