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Background: Compression bandages often are used after TKA to reduce swelling. However, the degree to which they are helpful has not been well characterized., Questions/purposes: The purpose of this study was to determine whether use of a compression bandage after TKA was associated with (1) less leg swelling (our primary endpoint); or (2) secondary study endpoints, including improved ROM of flexion and extension, lower visual analog scale (VAS) pain scores for worst pain and pain during physical therapy just before surgery, postoperative day (POD) 1, POD 2, and POD 28, or fewer wound complications within 90 days of surgery., Methods: A prospective, single-center, two-arm, parallel-group randomized controlled trial was conducted on 51 patients undergoing simultaneous, bilateral, primary TKA between February 2015 and August 2016. Patients were excluded if they had a body mass index > 40 kg/m, a history of a venous thromboembolic event, an allergy to the dressing or compression bandage, or lymphedema in one or both legs. Participants averaged a mean age of 62 years (range, 40-83 years). In all patients, we released the tourniquet after full wound closure, and we applied an Aquacel dressing to both limbs. Patients were randomized by opaque envelope, and the compression bandage was applied to the randomized limb. For each leg, study personnel not involved in patient care measured the patients' limb circumference (thigh, knee, and tibia), ROM, and VAS pain scores 24 hours after surgery, 48 hours after surgery, and on POD 28. The minimal clinically important difference for circumference was 2 cm with a SD of 2 cm in the circumference. For VAS, it was 2 points with a SD of 2. For ROM, it was 10° with a SD of 15. We conservatively picked an effect size of 0.5 SD and assumed a correlation between limbs of 0.3. This set the power level at 0.80 with an α error of 0.05; thus, a power analysis for paired t-tests indicated that 45 patients would be an appropriate sample size. There were 29 patients randomized to the right leg group and 22 patients randomized to the left leg group. There were no differences between the limb with and without the compression bandage preoperatively., Results: Postoperatively, there were no differences between the groups in terms of leg swelling at the thigh (POD 1: mean ± SD = 51 ± 6 with compression bandage versus mean ± SD = 51 ± 6 without compression bandage, mean Δ = - 0.14, 95% confidence interval [CI], -0.65 to 0.37], p = 0.586; POD 2: mean ± SD = 53 ± 6 with compression bandage versus mean ± SD = 53 ± 7 without compression bandage, mean Δ = -0.22, 95% CI, -0.95 to 0.51, p = 0.548; POD 28: mean ± SD = 47 ± 6 with compression bandage versus mean ± SD = 47 ± 6 without compression bandage, mean Δ = -0.01, 95% CI, -0.39 to 0.38, p = 0.975), knee (POD 1: mean ± SD = 45 ± 4 with compression bandage versus mean ± SD = 45 ± 5 without compression bandage, mean Δ = -0.44, 95% CI, -1.16 to 0.28, p = 0.223; POD 2: mean ± SD = 46 ± 4 with compression bandage versus mean ± SD = 46 ± 4 without compression bandage, mean Δ = -0.30, 95% CI, -0.69 to 0.10, p = 0.137; POD 28: mean ± SD = 42 ± 5 with compression bandage versus mean ± SD = 42 ± 5 without compression bandage, mean Δ = 0.21, 95% CI, -0.34 to 0.76, p = 0.446), and shin (POD 1: mean ± SD = 40 ± 4 with compression bandage versus mean ± SD = 40 ± 4 without compression bandage, mean Δ = -0.22, 95% CI, -1.23 to 0.79, p = 0.659; POD 2: mean ± SD = 41 ± 4 with compression bandage versus mean ± SD = 41 ± 4 without compression bandage, mean Δ = -0.31, 95% CI, -0.72 to 0.09, p = 0.126; POD 28: mean ± SD = 37 ± 4 with compression bandage versus mean ± SD = 37 ± 4 without compression bandage, mean Δ = -0.34, 95% CI, -0.92 to 0.24, p = 0.246). There were no differences between the groups in terms of flexion ROM (POD 1: mean ± SD = 56 ± 25 with compression bandage versus mean ± SD = 58 ± 22 without compression bandage, mean Δ = -2.63, p = 0.234; POD 2: mean ± SD = 64 ± 20 with compression bandage versus mean ± SD = 63 ± 23 without compression bandage, mean Δ = 1.22, p = 0.534; POD 28: mean ± SD = 101 ± 20 with compression bandage versus mean ± SD = 102 ± 20 without compression bandage, mean Δ = -1.64, p = 0.103) and extension (POD 1: mean ± SD = 12 ± 7 with compression bandage versus mean ± SD = 12 ± 7 without compression bandage, mean Δ = 0.51, p = 0.328; POD 2: mean ± SD = 9 ± 5 with compression bandage versus mean ± SD = 10 ± 6 without compression bandage, mean Δ = -1.28, p = 0.061; POD 28: mean ± SD = 6 ± 14 with compression bandage versus mean ± SD = 4 ± 4 without compression bandage, mean Δ = 2.19, p = 0.252). With the numbers available, we observed greater maximal postoperative pain for the limb with the compression bandage than the control limb on POD 1 and POD 2, but not on POD 28 (POD 1: mean ± SD = 8 ± 3 with compression bandage versus mean ± SD = 7 ± 3 without compression bandage, mean Δ = 0.66, p = 0.030; POD 2: mean ± SD = 7 ± 2 with compression bandage versus mean ± SD = 7 ± 3 without compression bandage, mean Δ = 0.80, p = 0.008; POD 28: mean ± SD = 4 ± 3 with compression bandage versus mean ± SD = 3 ± 3 without compression bandage, mean Δ = 0.14, p = 0.526). Likewise, there was greater pain during physical therapy for the limb with the compression bandage than the limb without on POD 2, but not on POD 1 and POD 28 (POD 1: mean ± SD = 7 ± 3 with compression bandage versus mean ± SD = 6 ± 3 without compression bandage, mean Δ = 0.29, p = 0.460; POD 2: mean ± SD = 8 ± 2 with compression bandage versus mean ± SD = 7 ± 3 without compression bandage, mean Δ = 0.67, p = 0.018; POD 28: mean ± SD = 5 ± 2 with compression bandage versus mean ± SD = 5 ± 3 without compression bandage, mean Δ = 0.14, p = 0.600). With the numbers available, we observed no difference in 90-day wound healing complications between the limb with and the limb without the compression dressing; however, the sample size was too small to analyze this in a meaningful statistical way. Overall, there were 6% total wound complications in the compression bandage group and 12% total wound complications in the group without the compression bandage (odds ratio [OR], 0.47; p = 0.487). Drainage was not observed in the group with the compression bandage, whereas the group without the compression bandage had 6% drainage (OR, 0.00; p = 0.243). There were no deep infections or reoperations within 90 days postoperatively., Conclusions: Applying a compression bandage after TKA did not result in any clinical improvement in limb circumference, ROM, or pain. Based on this study, we believe that applying a compression bandage after TKA neither benefits nor harms the patient. Thus, we no longer use compression dressings for routine primary TKA., Level of Evidence: Level I, therapeutic study.

Background: Length of stay after total hip arthroplasty (THA) has decreased over the last two decades. However, published studies that have examined same-day and early discharge protocols after THA have been done in highly selected patient groups operated on by senior surgeons in a nonrandomized fashion without control subjects., Questions/purposes: The purpose of this study was to evaluate and compare patients undergoing THA who are discharged on the same day as the surgery ("outpatient," less than 12-hour stay) with those who are discharged after an overnight hospital stay ("inpatient") with regard to the following outcomes: (1) postoperative pain; (2) perioperative complications and healthcare provider visits (readmission, emergency department or physician office); and (3) relative work effort for the surgeon's office staff., Methods: A prospective, randomized study was conducted at two high-volume adult reconstruction centers between July 2014 and September 2015. Patients who were younger than 75 years of age at surgery, who could ambulate without a walker, who were not on chronic opioids, and whose body mass index was less than 40 kg/m 2 were invited to participate. All patients had a primary THA performed by the direct anterior approach with spinal anesthesia at a hospital facility. Study data were evaluated using an intention-to-treat analysis. A total of 220 patients participated, of whom 112 were randomized to the outpatient group and 108 were randomized to the inpatient group. Of the 112 patients randomized to outpatient surgery, 85 (76%) were discharged as planned. Of the remaining 27 patients, 26 were discharged after one night in the hospital and one was discharged after two nights. Of the 108 patients randomized to inpatient surgery with an overnight hospital stay, 81 (75%) were discharged as planned. Of the remaining 27 patients, 18 met the discharge criteria on the day of their surgery and elected to leave the same day, whereas nine patients stayed two or more nights., Results: On the day of surgery, there was no difference in visual analog scale (VAS) pain among patients who were randomized to discharge on the same day and those who were randomized to remain in the hospital overnight (outpatient 2.8 ± 2.5, inpatient 3.3 ± 2.3, mean difference -0.5, 95% confidence interval [CI], -1.1 to 0.1, p = 0.12). On the first day after surgery, outpatients had higher VAS pain (at home) than inpatients (3.7 ± 2.3 versus 2.8 ± 2.1, mean difference 0.9, 95% CI, 0.3-1.5, p = 0.005). With the numbers available, there was no difference in the number of reoperations, hospital readmissions without reoperation, emergency department visits without hospital readmission, or acute office visits. At 4-week followup, there was no difference in the number of phone calls and emails with the surgeon's office (outpatient: 2.4 ± 1.9, inpatient: 2.4 ± 2.2, mean difference 0, 95% CI, -0.5 to 0.6, p = 0.94)., Conclusions: Outpatient THA can be implemented in a defined patient population without requiring additional work for the surgeon's office. Because 24% (27 of 112) of patients planning to have outpatient surgery were not able to be discharged the same day, facilities to accommodate an overnight stay should be available., Level of Evidence: Level I, therapeutic study.

Background: Elevated temperatures after total joint arthroplasty (TJA) are common and can be a source of anxiety both for the patient and the surgical team. Although such fevers rarely are caused by acute infection, many patients are subjected to extensive testing for elevated body temperature after surgery. We recently implemented a multimodal pain management regimen for TJA, which includes acetaminophen, pregabalin, and celecoxib or toradol, and because some of these medications have antipyrexic properties, it was speculated that this protocol might influence the frequency of postoperative pyrexia., Questions/purposes: The purpose of this study was to determine whether patients treated under this protocol were less likely to exhibit postoperative fever after primary TJA, compared with a historical control group, and whether they were less likely to receive postoperative testing as part of a fever workup., Methods: We compared 1484 primary TJAs in which pain was controlled primarily with opioid-based relief from July 2004 to December 2006 with 2417 procedures from July 2009 to December 2011 during which time multimodal agents were used. The same three surgeons were responsible for care in both of these cohorts. Oral temperature readings in the first 5 postoperative days (POD) were drawn from a review of medical records, which also were evaluated for fever workup tests, including urinalysis, urine culture, chest radiograph, and blood culture. Fever was defined by the presence of a temperature measurement over 38.5 °C. Patients having preoperative fever or postoperative fever starting later than POD 5 were excluded. Before surgery, there were no differences between the groups' temperature measurements., Results: Fewer patients developed fever in the multimodal analgesia group than in the control group (5% versus 25%, p < 0.001). Furthermore, fewer patients underwent workup for fever in the multimodal analgesia cohort (1.8% of patients undergoing 155 individual tests) compared with the control cohort (9.8% of patients undergoing 247 individual tests; p < 0.001)., Conclusions: In addition to fewer adverse effects and better pain control, the multimodal analgesia protocol has the hidden benefit of dampening the temperature response to the surgical insult of TJA. The decreased rate of postoperative fever avoids unnecessary anxiety for the patient and the treating team and reduces healthcare resource use occasioned by working up postoperative fever., Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Background: The most effective agent for prophylaxis against venous thromboembolic disease after total joint arthroplasty (TJA) remains unknown. The paucity of literature comparing different methods of pulmonary embolism (PE) prophylaxis and fear of litigation make it difficult for surgeons to abandon the use of aggressive chemical prophylaxis., Questions/purposes: We compared the (1) overall frequency of symptomatic PE, (2) risk of symptomatic PE after propensity matching that adjusted for potentially confounding variables, and (3) other complications and length of stay before and after propensity matching in patients undergoing TJA at our institution who received either aspirin or warfarin prophylaxis., Methods: A total of 28,923 patients underwent TJA between January 2000 and June 2012 at our institution, had either aspirin (325 mg twice daily; 2800 patients) or warfarin prophylaxis (26,123 patients), and were registered in our institutional electronic database. The incidence of symptomatic PE, symptomatic deep vein thrombosis (DVT), hematoma formation, infection, wound complications, and mortality up to 90 days postoperatively was collected from the database. We performed multivariate analysis and 3:1 and 5:1 propensity score matching for comorbid and demographic variables., Results: The overall symptomatic PE rate was lower (p < 0.001) in patients receiving aspirin (0.14%) than in the patients receiving warfarin (1.07%). This difference did not change after matching. The aspirin group also had significantly fewer symptomatic DVTs and wound-related problems and shorter hospital stays, which did not change after matching., Conclusions: After publication of the American Academy of Orthopaedic Surgeons' guidelines, some surgeons have utilized aspirin as thromboprophylaxis after TJA. Based on our findings from a large institutional database, aspirin offers suitable prophylaxis against symptomatic PE in selected patients.

Background: Although infections are a major cause of morbidity and mortality after total joint arthroplasty (TJA), little is known about nationwide epidemiology and trends of infections after TJA., Questions/purposes: We therefore determined (1) trends of postoperative pneumonia, urinary tract infection (UTI), surgical site infection (SSI), sepsis, and severe sepsis after TJA; (2) risk factors of these infections; (3) effect of these infections on length of stay (LOS) and hospital charges; and (4) the infection-related mortality rate and its predictors., Methods: The International Classification of Diseases, 9th Revision codes were used to identify patients who underwent TJA and were diagnosed with aforementioned infections during hospitalization in the Nationwide Inpatient Sample database from 2002 to 2010. Multivariate analysis was performed to identify risk factors of these infections., Results: Rates of pneumonia, UTI, SSI, sepsis, and severe sepsis were 0.74%, 3.26%, 0.31%, 0.25%, and 0.15%, respectively. Number of comorbidities and type of TJA were independent predictors of infection. Mortality decreased during the study period (odds ratio, 0.87; 95% confidence interval, 0.86-0.89). The median LOS was 3 days without complications but increased in the presence of SSI (median, 7 days), sepsis (median, 12 days), and severe sepsis (median, 15 days). Occurrence of pneumonia, sepsis, and severe sepsis increased risk of mortality 5.2, 8.5, and 66.2 times, respectively., Conclusions: Rates of UTI, pneumonia, and SSI but not sepsis and severe sepsis are apparently decreasing. The likelihood of infection is increasing with number of comorbidities and revision surgeries. Rate of sepsis-related mortality is also decreasing., Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Background: Acute postoperative infection after total hip arthroplasty (THA) is typically treated with irrigation and débridement and exchange of the modular femoral head and acetabular liner. Given a rate of failure exceeding 50% in some series, a one-stage exchange has been suggested as a potential alternative because it allows more thorough débridement and removal of colonized implants. To date, most studies published on the one-stage exchange have used microbe-specific antibiotic-laden bone cement with only one small single-institution series that reported outcomes after a cementless one-stage exchange., Questions/purposes: We determined whether a one-stage cementless exchange for treating acute postoperative infection after THA would result in infection control with component retention and normalization of infection markers., Methods: We retrospectively identified 27 patients who underwent a one-stage exchange performed for an acute (≤6 weeks) postoperative infection after THA from April 2004 to December 2009. Primary cementless components were used both at the time of the index arthroplasty and the revision in all patients. Surgery was followed by a 6-week course of culture-specific antibiotics in all patients and a variable course of oral antibiotics. Our primary outcome was retention of the implants at most recent followup and our secondary outcome was normalization of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) at most recent followup. Patients were followed until failure or a minimum of 2 years., Results: At a minimum followup of 27 months (mean, 50 months; range, 27-89 months), 19 of the 27 patients (70%) retained their implants but four required further operative débridement with component retention at a mean of 3 weeks (range, 2-6 weeks) to obtain control of infection. Thus, an isolated single-stage exchange was successful in 15 of the 27 patients (56%). Eight patients (30%) ultimately had a two-stage exchange for persistent infection; seven of these patients required no further surgery, whereas one patient required a second two-stage exchange. Of those patients retaining their prosthesis after one-stage exchange and tracked with ESR and CRP, four (33% [four of 12]) had elevated values without other signs or symptoms of recurrent infection., Conclusions: For acute postoperative infection after primary THA, a one-stage cementless exchange allowed 70% of patients to retain their implants at most recent followup. Of those patients who ultimately went on to a two-stage exchange, only one required a second two-stage exchange., Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Background: Postoperative pain after total knee arthroplasty remains one of the most important challenges facing patients undergoing this surgery. Providing a balance of adequate analgesia while limiting the functional impact of regional anesthesia and minimizing opioid side effects is critical to minimize adverse events and improve patient satisfaction., Questions/purposes: We asked whether bupivacaine delivered through an elastomeric device decreases the (1) patients' perception of pain after TKA; (2) narcotic consumption; and (3) narcotic-related side effects as compared with a placebo., Methods: In this prospective, double-blind, placebo-controlled study, all patients received standardized regional anesthesia, a preemptive and multimodal analgesic protocol, and a continuous intraarticular infusion at 5 mL/hour through an elastomeric infusion pump. The patients were randomized to receive either an infusion pump filled with (1) 300 mL of 0.5% bupivacaine, the experimental group (n = 75); or (2) 300 mL of 0.9% normal saline solution, the control group (n = 75). Data concerning postoperative pain levels through a visual analog scale, postoperative opioid consumption, opioid-related side effects, and complications were collected and analyzed., Results: Patients in the experimental group receiving the bupivacaine reported a reduction in pain levels in highest, lowest, and current visual analog scale scores compared with the placebo group on the first postoperative day and highest visual analog scale score on postoperative Day 2 along with a 33% reduction in opioid consumption on postoperative Day 2 and a 54% reduction on postoperative Day 3., Conclusion: In patients undergoing TKA, continuous intraarticular analgesia provided an effective adjunct for pain relief in the immediate postoperative period without the disadvantages encountered with other analgesic methods.

Background: C-reactive protein (CRP) serum assays are a standard element of the diagnostic workup for periprosthetic joint infection (PJI). However, because CRP is a marker for systemic inflammation, this test is not specific to PJI., Questions/purposes: Our purpose was to assess whether synovial fluid and serum assays alone could differentiate between infected and uninfected revision knee arthroplasties and to determine which of these methods had the greatest diagnostic accuracy., Methods: We collected synovial fluid specimens from 66 patients undergoing revision total knee arthroplasty. Patients were judged uninfected or infected by standardized criteria. Synovial CRP levels were measured using an individual CRP assay (15 samples; 10 infected, five uninfected) and a multiplex immunoassay platform (59 samples; 25 infected, 34 uninfected). Results from preoperative standard serum CRP assays conducted were also collected (55 samples; 25 infected, 30 uninfected). Sensitivity, specificity, and receiver operating characteristic curve analyses were performed for each assay with a diagnosis of infection based on previously established criteria., Results: Synovial CRP concentrations differed between infected and uninfected joints in the multiplex and serum analyses. The area under the curve was 0.84 for the individual assay, 0.91 for the multiplex assay, and 0.88 for the serum CRP assay. Sensitivity and specificity were 70.0% and 100.0% for the individual enzyme-linked immunosorbent assay, 84.0% and 97.1% for the multiplex assay, and 76.0% and 93.3% for the serum CRP assay., Conclusions: An assay measuring CRP in synovial fluid may be more accurate in diagnosing PJI than the standard serum CRP assay. We believe such an assay holds promise as a new diagnostic marker for PJI.

Background: Modular femoral stems are one option for revision THA surgeons and allow offset restoration, leg length discrepancy correction, and stability independent of distal stem fixation. The complexity of revision THA usually leads surgeons to use multiple revision hip designs to address these issues., Questions/purposes: We evaluated functional outcomes with a revision modular system and determined whether such a system achieved initial distal fixation, femoral offset restoration, leg length equalization, and hip stability., Methods: We prospectively followed 118 patients in whom a modular stem system was used for reconstruction of their failed index femoral stem. Sixty-nine hips were classified as Type I (classification of Paprosky et al.), 35 as Type II, 17 as Type III, and one as Type IV. Functional assessment was achieved using patient- and physician-administered outcome evaluations (SF-36, WOMAC, Lower Extremity Activity Scale, Harris hip score). Stem fixation, offset restoration, leg length discrepancy, and hip stability were evaluated radiographically. Complications were also recorded. Minimum followup was 2 years (average, 4 years; range, 2-7 years)., Results: Average values on all functional outcome evaluations showed improvement at latest followup. Distal bone ingrowth fixation was obtained in 100% of the patients, offset was corrected in 66%, leg length discrepancy was corrected in 78%, and stability was achieved in 97%. No failures or fractures at the body to stem junction were seen at latest followup., Conclusions: Modular femoral components achieved functional outcomes and were useful to address distal fixation, femoral offset restoration, leg length equalization, and hip stability when revising failed femoral components., Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Background: In recent years, a number of alternative bearing surfaces, such as ceramic on ceramic, are being used in THA. Squeaking after THA is a recently recognized complication; however, its incidence is unknown., Questions/purposes: Find the incidence of squeaking; when it ensues; activities associated to squeaking; its natural history, and outcome of revisions for squeaking., Methods: A prospective observational study between 2002 and 2007; yield 1486 ceramic-on-ceramic THA performed at our institution. All patients were followed up by office visits or by phone, to obtain information regarding squeaking, pain and function. Minimum followup was 2.5 years (mean, 5.5 years; range, 2.5-7.9 years)., Results: Ninety-five of the 1486 hips (6%) developed squeaking after THA, 39 females (44%) and 49 males (56%) with an average age of 49.9 years. Squeaking began on average 19.7 months after surgery but not associated with pain or functional impairment in any patient. Squeaking could be heard during walking (38%), ascending stairs (24%), bending forward (21%), and other activities (18%), was constant in 26% of the patients and intermittent in 74%. The intensity and frequency remained similar over time in 70% of the patients., Conclusions: Squeaking is a real phenomenon that occurred in about 6% of our patients. The etiology for this problem remains elusive and is likely to be multifactorial in nature. Squeaking, when developed, does not seem to be self-limited and persists in the majority. Nine patients underwent revision arthroplasty for squeaking. No fractures or other implant-related issues were observed., Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Unlabelled: An extended-release epidural morphine (EREM) has been introduced to improve postoperative pain management. Studies have shown the effectiveness of this agent in providing better pain control and patient satisfaction for patients undergoing total joint arthroplasty. We evaluated postoperative pain relief by comparing average daily pain scores and opioid use with those of the control group. Safety was measured by comparing the occurrence of postoperative complications, nausea and vomiting, pruritus, and respiratory depression between the two groups. Between February 2006 and March 2008, we selected 203 patients to receive EREM for THA. These patients were matched in a 2:1 ratio with patients undergoing THA and receiving spinal anesthesia. We retrospectively reviewed all major and minor postoperative complications from a prospective database. Patients receiving EREM had lower pain scores than patients not receiving EREM on Postoperative Day 1 (POD 1) but not POD 2, or POD 3. Patients receiving EREM experienced a slightly higher incidence of pulmonary embolism and supraventricular tachycardia. Patients receiving EREM also experienced more nausea and vomiting and pruritus. We found EREM provided better pain relief on POD 1 at the expense of a slightly higher incidence of side effects compared with spinal anesthesia alone., Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Unlabelled: Porous surfaces are intended to enhance osteointegration of cementless implants. Tantalum has been introduced in an effort to enhance osseointegration potential of uncemented components. We therefore compared the clinical outcome of acetabular components with two different porous surfaces. We retrospectively reviewed 283 patients (295 hips) who underwent cementless revision hip arthroplasty with either an HA-coated titanium cup (207 patients, 214 hips) or porous tantalum cup (79 patients, 81 hips). The minimum followup was 24 months in both groups (titanium: average 51.8 months, range, 24-98 months; tantalum: average, 35.4 months, range, 24-63 months). The titanium and tantalum groups had a mechanical failure rate (clinical plus radiographic) of 8% and 6%, respectively. In hips with minor bone deficiency (type 1, 2A, 2B using the classification of Paprosky et al.), 6% of titanium cups and 4% of tantalum cups failed. In hips with major bone deficiency (type 2C, 3), 24% of titanium cups and 12% of tantalum cups developed failure. In the major bone deficiency group, the tantalum cups had fewer numbers of lucent zones around the cup. Eighty-two percent of titanium cups that failed did so at 6 months postoperatively or later, whereas 80% of tantalum cups that failed did so in less than 6 months. Radiographically in the major group, tantalum cups yielded better fixation., Level of Evidence: Level III, retrospective comparative study. See the Guidelines for Authors for a complete description of levels of evidence.

Unlabelled: Polyethylene wear and osteolysis are not uncommon in THA mid- and long-term. In asymptomatic patients the dilemma faced by the orthopaedic surgeon is whether to revise the cup and risk damage to the supporting columns and even pelvic discontinuity or to perform isolated polyethylene exchange and risk a high rate of postoperative recurrent instability and dislocation that will necessitate further surgery. We retrospectively reviewed 62 patients (67 hips) who underwent revision arthroplasty for polywear and osteolysis. Thirty-six hips had isolated polyethylene exchange, while 31 had full acetabular revision. The minimum followup was 2 years (mean, 2.8 years; range, 2-5 years). Three of 36 hips with a retained cup grafted through the cup holes failed within 5 years due to acetabular loosening. One of 31 hips with full revision underwent re-revision for aseptic cup loosening at 5 months postoperatively. Although we do not recommend prophylactic revision of all cups for polywear and osteolysis, the patient may be warned of the possibility of an approximate 10% failure rate when retaining the acetabular component. We do, however, advocate cup extraction in the following situations: damage to the locking mechanism, erosion of the femoral head through the liner and into the cup damaging the metal, and a malpositioned component that may jeopardize the stability of the revision., Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Wear debris from metal-on-polyethylene articulation in conventional total hip arthroplasty can limit the implant's longevity. Modern ceramic material with high wear resistance and low fracture risk has the potential to extend the lifetime of total hip arthroplasty, which makes the procedure potentially more suitable for young, active patients. Concerns with brittle ceramic material include fracture risk, the "squeak" phenomenon, and potentially a higher dislocation rate secondary to limited neck lengths and liner options. We therefore determined the early dislocation rate in modern ceramic-on-ceramic total hip arthroplasty. In 1635 total hip arthroplasties performed over the 9-year period (1996-2005), we observed three anterior and 15 posterior dislocations (1.1%). All were treated successfully, one with a revision and 17 with closed reduction under general anesthesia. Ceramic-on-ceramic total hip arthroplasty can be a good alternative bearing surface with a low dislocation rate.

Epidural hypotensive anesthesia can, in addition to imparting numerous intraoperative benefits, provide excellent postoperative pain control for patients having joint arthroplasties. However, because of the risk of epidural hematoma, epidural anesthesia is not coadministered with anticoagulation in some centers. We retrospectively ascertained, by chart review, the incidence of epidural hematoma in 11,235 patients having 12,991 knee arthroplasties at our institution who received oral anticoagulation and epidural anesthesia for their surgery. Warfarin was administered on the day of surgery. With the exception of 212 patients, the epidural catheter was removed within 48 hours of surgery. Based on clinical examinations, we detected no epidural hematomas. For 1030 patients (1038 knees) whose charts were reviewed in detail, the mean international normalized ratio at the time of removal of the epidural catheter was 1.54 (range, 0.93-4.25). We identified no other complications related to the coadministration of epidural anesthesia and warfarin. Although administration of epidural anesthesia in patients with coagulopathy can be detrimental, we recognized no cases of epidural hematoma causing neurologic symptoms in patients receiving controlled oral anticoagulation after total knee arthroplasty.

Our research group developed an implant retrieval program to study in vivo degradation of polyethylene. We now have evidence to support our hypothesis that degradation of radiation-sterilized polyethylene occurs in the body for not only historical gamma air sterilized liners, but also for conventional gamma inert sterilized (ArCom) and annealed highly crosslinked polyethylene (Crossfire) liners as well. Our research has also led to the discovery that the most severe manifestations of in vivo oxidation typically occur in regions of the liner experiencing minimal wear, such as the rim of the component, where the body fluids (containing oxidizing species) have access to the polyethylene. Our data from historical, ArCom, and Crossfire retrievals all point to a similar scenario in which the femoral head limits the in vivo oxidation of polyethylene at the bearing surface. Consequently, provided rim impingement does not occur, and the polyethylene locking mechanisms remain relatively isolated from oxidizing fluid, in vivo oxidation does not seem to be clinically important in the first 10 years of implantation for conventional gamma sterilized polyethylene. We conclude that in vivo degradation should be included among the list of potential long-term failure modes for modular polyethylene components for total hip arthroplasty.

We compared the outcomes of bilateral total hip arthroplasty performed as a one-stage or two-stage procedure. We retrospectively identified 196 patients (392 hips) with bilateral arthritis of the hip who underwent total hip arthroplasties: 98 patients (196 hips) as a one-stage procedure (one-stage group) and 98 (196 hips) as a two-stage procedure (two-stage group). All patients had uncemented components implanted under spinal anesthesia and had the same postoperative rehabilitation protocol. Both groups' functional outcomes were similar. The mean preoperative hemoglobin was 12.6 g/dL in the one-stage group and 12.9 g/dL in the two-stage group. The mean cumulative blood transfusion was 2.6 units in the one-stage group and 3.5 units in the two-stage group. Patients in the two-stage group had more complications, most commonly anemia and wound drainage. The total mean hospital stay was longer in the two-stage group (8.1 days; range, 5-39 days) compared with the one-stage group (4.3 days; range, 3-11 days). The mean total expenses were higher in the two-stage group (dollar 64,600) compared with the one-stage group (dollar 45,900). Young and healthy patients may be candidates for one-stage bilateral total hip arthroplasty without an increase in complications and with lower costs.

Decreased muscle damage is a reported benefit of minimally invasive surgical (MIS) approaches in total hip arthroplasty (THA). We compared the extent and location of muscle damage during THA using the MIS anterior Smith-Petersen and MIS posterior surgical approaches. THA was performed in six human cadavers (12 hips). One hip was assigned to the Smith-Petersen approach and the contralateral hip to the posterior approach. Muscle damage was graded with a technique of visual inspection to calculate a proportion of surface area damage. Less damage occurred in the gluteus minimus muscles and minimus tendon with the Smith-Petersen approach. A mean of 8% of the minimus muscle was damaged via the Smith-Petersen approach, compared to 18% via the posterior approach. The tensor fascia latae muscle was damaged (mean of 31%), as well as direct head of the rectus femoris (mean 12%) during the Smith-Petersen approach. The piriformis or conjoined tendon was transected in 50% of the anterior approaches to mobilize the femur. The posterior approach involved intentional detachment of the piriformis and conjoined tendon and measurable damage to the abductor muscles and gluteus minimus tendon in each specimen. Clinical outcome studies and gait analysis are necessary to ascertain the functional implications of these findings.

Minimally invasive surgery (MIS) and computer-assisted orthopaedic surgery (CAOS) options for total knee arthroplasty (TKA) have become increasingly popular. However, few controlled studies document their efficacy and safety. We examined the Internet for Knee Society members' websites to evaluate the level of promotion for these procedures in terms of direct (surgeon endorsed) and indirect (surgeon associated) information. On 92 websites, 22.7% made indirect reference to MIS TKA, while only 10.9% made a direct reference. Of the sites referencing MIS TKA, faster recovery was reported on 90% of indirect sites and 50% of direct sites. Specific risks were discussed on only 35% of indirect sites, and on only 20% of direct sites. CAOS TKA was discussed on 6.5% of indirect sites and on 5.4% of direct sites. Although MIS and CAOS TKA are frequently discussed on the Internet, only a small percentage of KS members directly promote these techniques (10.9% and 5.4%, respectively). Information was often indirectly associated with KS surgeons through institutional websites or hospital affiliations. Information indirectly associated with a surgeon may be mistaken as endorsing the procedure by a prospective patient.

Most patients exhibiting instability after total hip arthroplasty can be treated nonoperatively. However, instability may become recurrent and require surgical intervention. Abductor insufficiency and component malpositioning constitute two of the most important causes of recurrent instability, although the exact cause may not be identifiable in some patients. There is relative scarcity of reports in the literature regarding the outcome of surgical intervention for recurrent instability; however, it is known that surgical intervention is likely to have a better outcome in patients for whom the cause of recurrent instability can be identified. We hypothesized that component malpositioning, which may be subtle in some cases, is the cause of recurrent instability for many patients. The outcomes of revision arthroplasty in 93 patients who were treated at our institution for recurrent instability were reviewed. Component malpositioning was found to be the major cause of recurrent instability in this successfully treated cohort.

We evaluated the outcome of revision arthroplasty for polyethylene wear presenting as late dislocation. The computerized databases at two institutions were reviewed to identify all patients presenting with first time dislocation five or more years after total hip arthroplasty. Records and radiographs were then evaluated, and patients whose late dislocation occurred in the presence of greater than two millimeters of polyethylene liner wear with no other etiology for dislocation were identified. There were 22 patients with a mean age of 57.8 years at primary procedure. The average time from initial arthroplasty to dislocation was 9.0 years. Revision surgery to address polyethylene wear and instability was performed at a mean of 11.1 years (range 5.8 to 23 years). Revision surgery restored stability to eighteen patients (eighty-two percent). Polyethylene wear can and is associated with late dislocation after hip arthroplasty. Exchange of polyethylene lining of a metal backed implant or revision of the all polyethylene acetabular component can successfully address late instability in the majority of patients.

Unlabelled: The management of periprosthetic fracture around the knee remains a challenging problem. The objective of this article was to review the general concepts, treatment algorithms, and the overall treatment outcomes of femoral and tibial periprosthetic fractures after total knee arthroplasty. This article aimed to highlight the deficiencies of the current classification systems that fail to provide a guideline for selection of appropriate treatment options. We proposed a new classification system for periprosthetic femoral fractures that takes into account the status of the prosthesis, the quality of distal bone stock, and the reducibility of the fracture. Type I fractures are those occurring in patients with good bone stock with the prosthesis being fixed and well positioned. Type IA fractures are either nondisplaced or easily reducible and can be treated conservatively. Type IB fractures are irreducible and require reduction and internal fixation. Type II fractures are defined as those occurring also in patients with good bone stock and being reducible, but either the components are loose or malpositioned. These fractures are treated by revision arthroplasty. Type III fractures are reducible or irreducible fractures that occur in patients with poor bone stock and in the vicinity of loose or malpositioned components. These fractures are treated by distal femoral replacement., Level of Evidence: Therapeutic study, level V (expert opinion). See Guidelines for Authors for a complete description of levels of evidence.

We searched the Internet for Web sites related to 106 members of the Hip Society. Web sites (private and/or hospital affiliated) for each surgeon were evaluated for the term "minimally invasive total hip replacement" and its related names. One hundred two of the 106 Hip Society members (96%) had Web sites. Of the 102 Web sites, eight Web sites had links to multiple members of the Hip Society, resulting in 94 distinct sites. Nineteen percent (19 of 102 members) of Hip Society members made reference to minimally invasive hip surgery. 11% (10 of 94 sites) of Web sites included references to minimally invasive hip surgery. When the terms fast or quicker recovery were evaluated, 14% (14 of 102 members) of surgeons used these terms. There were references to these terms on 6% (six of 94 sites) of the members' Web sites. Two incision techniques were discussed by only 10% (10 of 102 members) of members, and reported on 4% (four of 94 sites) of Web sites. In contrast, only 26% (five of 19 members) of Hip Society members and 30% (three of 10 sites) of Web sites reported the risks. Although minimally invasive hip arthroplasty frequently is discussed and advertised by some surgeons, only a small percentage of Hip Society members actually promote or make claims to these techniques on their Web sites.

Despite immense improvements, periprosthetic infection continues to compromise the result of otherwise successful joint arthroplasty. There are various limitations in the treatment of periprosthetic infection, the most important of which is the inability to deliver antibiotics to the local tissue without the need for intravenous administration. We have developed a novel route to covalently tether vancomycin to a metal (titanium) surface, which showed effective bactericidal activity because of a vancomycin coupling. The chemistry of tethering does not affect the biological activity of the biofactors that are attached to the metal surface. This technology holds great promise for the manufacturing of "smart" implants that can be self protective against periprosthetic infection, or can be used for the treatment of periprosthetic infections when they occur.

Complications associated with reimplantation of a total hip arthroplasty after resection or Girdlestone arthroplasty for treatment of an infected hip are not well-documented. Forty-four hips in 44 patients with a minimum 2-year followup (range, 2-9 years) from the time of reimplantation total hip arthroplasty were evaluated retrospectively. The average Harris hip score changed from 40 preoperatively to 78 at the latest followup. One patient had persistent infection requiring rerevision surgery, and another patient had rerevision surgery for recurrent dislocation. Complications related to the prosthesis consisted of dislocations in five patients (11.4%), recurrent infection in one patient (2.3%), trochanteric nonunion in four patients (9.1%), hematoma in one patient, heterotopic ossification in one patient, and postoperative wound drainage in one patient. Resection arthroplasty of the hip is highly effective in eradicating infection. In the current series, 97.7% of patients were free of infection at the latest followup. However, with an 11.4% dislocation rate and 39% of patients having a persistent limp, alternative approaches need to be evaluated which might reduce these complications.

The incidence of failure after knee replacement is low, yet it has been reported that more than 22,000 knee replacements are revised yearly. The purpose of the current study was to determine current mechanisms of failure of total knee arthroplasties. A retrospective review was done on all patients who had revision total knee arthroplasty during a 3-year period (September 1997-October 2000) at one institution. The preoperative evaluation in conjunction with radiographs, laboratory data, and intraoperative findings were used to determine causes of failure. Two hundred twelve surgeries were done on 203 patients (nine patients had bilateral surgeries). The reasons for failure listed in order of prevalence among the patients in this study include polyethylene wear, aseptic loosening, instability, infection, arthrofibrosis, malalignment or malposition, deficient extensor mechanism, avascular necrosis in the patella, periprosthetic fracture, and isolated patellar resurfacing. The cases reviewed included patients who had revision surgery within 9 days to 28 years (average, 3.7 years) after the previous surgery. More than half of the revisions in this group of patients were done less than 2 years after the index operation. Fifty percent of early revision total knee arthroplasties in this series were related to instability, malalignment or malposition, and failure of fixation.

The authors report their 15-year experience with primary total hip arthroplasty using collarless, tapered, porous-coated femoral stems (Trilock and Taperloc) in patients with osteoarthritis, rheumatoid arthritis, and in octogenarians. Excellent clinical results were achieved in all groups at latest followup. For the patients with Trilock stems, Taperloc stems, and patients who were octogenarians and patients with rheumatoid arthritis, Charnley pain scores were 5.6, 5.5, 5.7, and 5.7; Charnley function scores were 5.2, 5.1, 4.2, and 5.3; Harris hip scores were 92, 92, 82, and 93 points, respectively. There was a 2% rate of thigh pain with the Trilock, 4% with Taperloc, 4% in octogenarians, and 2% in patients with rheumatoid arthritis. In 96% of the patients in the Trilock group, in 100% of the patients in the Taperloc group, in 100% of the patients who were octogenarians, and in 100% of the patients with rheumatoid arthritis, femoral components showed radiographic evidence of bone ingrowth. There were six (12%) femoral component revisions in the Trilock group (all secondary to nonmodularity of the component at the time of acetabular revision), one femoral component revision in the Taperloc group and no femoral component revisions in the patients who were octogenarians or who had rheumatoid arthritis. Design features (collarless tapered wedge fit, circumferentially porous-coated) virtually ensure bone ingrowth and are thought to be responsible for the excellent clinical results and longevity.

Seventeen staged, bilateral total hip arthroplasties performed in 17 patients were reviewed to compare side-to-side polyethylene wear. Implants used on both sides were similar except for implant offset: one hip in each patient was replaced using a femoral component having a standard implant offset, whereas the other side had a lateral offset implant. The mean followup was 5.70 years (range, 2-10.2 years) on the side with a standard femoral implant and 5.67 years (range, 2-9.7 years) on the side with a lateralized femoral component. The only statistically different parameter between the sides was the femoral component offset. All other parameters affecting polyethylene wear, such as period of followup, head size, head type, cup size, cup inclination, medialization of cup, and patient-related factors were similar on both sides. On the side with a standard femoral component, the mean actual prosthetic offset (determined by manufacturer's specifications) was 35.2 mm and the radiologic offset was 31.5 mm. On the side with a lateralized femoral component, the actual prosthetic offset was 42.5 mm and the radiologic offset was 40.1 mm. The difference in offsets between the sides was statistically significant. The mean preoperative offset of the femur was 38.8 mm. Regression analysis revealed that only femoral component offset and cup size correlated significantly with linear wear rate. On the side with a standard femoral component, the linear wear rate was 0.21 mm per year, whereas on the side with a lateralized femoral component, the linear wear rate was 0.10 mm per year. The differences in the linear wear rates were significant. Lateralization of the femoral component in this series more closely restored preoperative hip biomechanics and significantly decreased polyethylene wear.

Seventy-one total hip arthroplasties with a cementless, wedge fit, cobalt chrome femoral component were reviewed in 60 patients at a minimum 10-year followup (mean, 11.5 years). For the femoral component, the mechanical failure rate was 5% and the revision rate for aseptic loosening was 0%. The mean Charnley scores for pain, function, and motion changed from preoperative mean values of 3.0, 2.7, and 3.2 to followup mean values of 5.7, 5.5, and 5.2, respectively. The followup mean Harris hip Score was 91. The incidence of thigh pain was 1.4% at 10-year followup. Ninety-five percent of femoral components showed radiologic evidence of stable, bone ingrowth fixation, whereas loosening was seen in 5% of stems. Despite the high incidence of acetabular osteolysis, no osteolysis was seen on the femoral side distal to the lesser trochanter. Nonmodularity of the femoral component led to unavoidable revision of stably fixed femoral components in seven (9.8%) hips during the revision of a loose socket. Design features (collarless, tapered, wedge fit, and circumferentially porous coated) were thought to be crucial to the superlative results with the cobalt chrome femoral component.

Radiographic subsidence of the femoral prosthesis and clinical results after unilateral and simultaneous bilateral uncemented total hip arthroplasty were compared. Patients who had bilateral total hip arthroplasty began weight-bearing as tolerated on both lower extremities the day after surgery. Patients who had undergone unilateral total hip arthroplasty were maintained at 10% weightbearing on the operative limb for 6 weeks after surgery. Patients in both groups were matched for age, gender, and weight. Minimal followup was 2 years. There was no difference between the two groups in terms of clinical results. Radiographic assessments were performed immediately after surgery, 6 weeks after surgery, and again at 2 years after surgery. Radiographs were reviewed by a single observer and analyzed with a digitized data recorder. Increased subsidence of the femoral prosthesis within the bilateral group was found at 6 weeks. The mean subsidence of the femoral prosthesis at 6 weeks for the bilateral total hip arthroplasty group was 0.86 mm (range, 0.18-2.60 mm) and for the unilateral group was 0.39 mm (range, 0.07-1.46 mm). However, subsidence occurring between 6 weeks and 2 years averaged 0.50 mm (range, 0.09-1.10 mm) for the bilateral group and 0.54 mm (range, 0.03-0.99 mm) for the unilateral group. This difference was not significant. At the 2-year followup, all femoral prostheses in both groups appeared radiographically stable with evidence of bone ingrowth and no indications of loosening. Thus, immediate weightbearing after bilateral total hip arthroplasty in this study resulted in more initial subsidence (during the first 6 weeks after surgery) of the femoral prosthesis but did not preclude the prosthesis from becoming stable and achieving bone ingrowth. Patients in both groups obtained satisfactory clinical results. Because initial stability and bone ingrowth are factors influenced by prosthesis design, the results of this study may not be applicable to all implants.

One hundred consecutive, primary simultaneous bilateral total knee arthroplasties were prospectively compared with 100 consecutive, primary unilateral total knee arthroplasties in reference to relative risk, complications, cost, and need for rehabilitation. All procedures were performed using identical preoperative, intraoperative, and postoperative protocols. Postoperative confusion was approximately four times greater in the simultaneous bilateral total knee arthroplasties group (29% versus 7%), which was thought to represent an increased incidence of fat embolism. Cardiopulmonary complications were approximately three times greater after simultaneous bilateral total knee arthroplasties (14% versus 5%), and most commonly involved arrhythmias. The increased stress on the cardiopulmonary system with simultaneous bilateral total knee arthroplasties may make this procedure contraindicated in certain patients with preexisting disease. There was an approximately 17 times greater need for banked blood in the simultaneous bilateral total knee arthroplasties group (17% versus 1%), which is alarming given the persistent concerns of transfusion related disease transmission. Although the length of hospitalization was similar (6.4 days simultaneous bilateral total knee arthroplasties versus 6 days unilateral total knee arthroplasty), 89% of the patients in the simultaneous bilateral total knee arthroplasties group required a rehabilitation stay versus 45% of the patients in the unilateral total knee arthroplasty group. Total hospital charges averaged $53,168 for simultaneous bilateral total knee arthroplasties versus $32,598 for unilateral total knee arthroplasty. Total rehabilitation charges were similar. The relative cost savings implicit by doing simultaneous bilateral total knee arthroplasties seem to be at least partially offset by the approximately two times greater need for rehabilitation in this group. The true safety, efficacy, relative risk, and total cost analysis of simultaneous bilateral total knee arthroplasties demands further critical evaluation.

The Medical Outcomes Study Short Form-36 was used preoperatively and 2 years postoperatively to compare patients' self reported assessment of health and function between 151 patients who had primary total hip replacement and 49 patients who had total hip revision, 149 patients who had primary total knee replacements, 41 patients who had lumbar laminectomy, and 43 patients who had scoliosis surgery. Primary total hip arthroplasty and lumbar laminectomy posted equivalent followup scores. Primary total hip arthroplasty showed significant improvements in physical function and health perception when compared with revision total hip arthroplasty; all other health parameters were similar. Primary total hip arthroplasty showed significantly better followup scores and greater improvement in scores in four of nine categories of the SF-36 when compared with primary total knee arthroplasty (despite identical scores preoperatively). Despite a higher level of assessed health preoperatively, patients who had scoliosis surgery compared least favorably with patients who had primary total hip arthroplasty at 2 years followup. In terms of patient self assessment of health and function, primary total hip arthroplasty and lumbar laminectomy for radiculopathy gave the best results.

One hundred two patients underwent 105 primary uncemented total hip arthroplasties and were reviewed at a minimum of 5 years after operation (mean, 6.1 years). The components were titanium alloy with a titanium plasma spray coating. The acetabular revision rate was 11.4%. Acetabular cavitary lytic lesions were identified in 25.5% at 5 years. All acetabular revisions were performed for a combination of wear and osteolysis. One femoral revision was performed to facilitate an acetabular revision, but the femoral revision rate for aseptic loosening was 0%. In addition, no femoral components had subsided or were thought to be loose radiographically. Thigh pain was present in 4% at 5 years. Despite the 25.5% incidence of acetabular osteolysis, distal femoral lysis was not seen and only 5% showed focal osteolysis in the trochanteric region proximal to the circumferential porous coating of the femoral component. Component design features were thought to be critical to the excellent performance of the femoral component and to the poor performance of the acetabular component.

The authors report the results of a prospective study examining the benefits of daily continuous passive motion combined with physical therapy, compared with physical therapy alone, in 103 consecutive osteoarthritic patients undergoing primary total knee arthroplasty. The first 51 patients received continuous passive motion initiated in the recovery room and the next 52 patients did not receive continuous passive motion. Both groups underwent an identical physical therapy protocol starting on the first postoperative day. At discharge, there was a significant increase in active flexion in the continuous passive motion group. There were no significant differences regarding pain, wound healing, knee swelling, wound drainage, pulmonary embolism, or length of hospital stay between the 2 groups. At 2 years, there were no clinical differences in the motion or knee scores. Knee manipulation was done for < 50 degrees flexion after the tenth postoperative day. There were 5 manipulations in the noncontinuous passive motion group and none in the continuous passive motion group. The entire costs associated with the 5 manipulations was $48,274 or $937 per patient not receiving continuous passive motion. The average daily inpatient rental of the machine was $60 per day. Continuous passive motion is efficacious in increasing short-term flexion and decreasing the need for knee manipulation without increasing costs.

Recementing a femoral prosthesis into a retained cement mantle was done during revision total hip arthroplasty in 15 patients using ultrasonic tools to reshape the existing cement mantle. Early complications such as bone perforation or fracture were avoided. The 2-year followup in 4 patients revealed no adverse effect on the bone-cement interface as judged radiographically. One patient had rerevision for instability at 1 year after operation. Indications for this technique include isolated failure of the cement-prosthesis interface, femoral component fracture, or isolated acetabular revision in which exposure needs, instability, leg length inequality, or femoral-head size dictated change of the femoral component.

In 20 patients with patellar "clunks" after posterior stabilized total knee arthroplasty, the average time to presentation was 10.7 months postarthroplasty. All patients demonstrated an audible and often painful "clunk" during extension. Fourteen procedures (11 arthroscopic debridements and three patellar component revisions) were performed in 12 patients. At reoperation, a suprapatellar fibrous nodule was seen to wedge into the intercondylar notch during flexion and dislodge during extension, generating the symptoms. The disorder resolved after nodule excision. Although four recurrences arose after arthroscopic debridements, none developed after arthrotomy and patellar button revision. Femoral component design, postsurgical inflammation, and altered extensor mechanics are potential etiologic agents of this complication.

Seventy-one cemented total hip arthroplasties (THAs) in 66 patients were compared with 70 cementless THAs in 61 patients. The cemented and cementless components were identical except for the presence of a porous proximal surface on the cementless component. The mean follow-up time was 4.3 years in the cemented group and 4.1 years in the cementless group, with a minimum follow-up of two years. Postoperative Charnley pain scores were identical for both groups, as was the incidence of limp. The final Charnley function score, however was significantly higher in the cementless group (5.6) than in the cemented group (5.1). One revision was performed in the cemented group, none in the cementless group. Complete demarcation of the bone-cement interface was presented in two cemented components and was associated with subsidence. Three cementless components had early subsidence, and two of these had complete radiopaque lines around the porous surface. None of these three patients, however, had unsatisfactory pain or function scores. The most important finding of this study is the equivalence of clinical results noted in both cemented and cementless THA as late as six years after operation.

With a greater understanding of the prevention of thromboembolic complications, the incidence of fatal pulmonary embolism after total joint arthroplasty has declined. Although much of our knowledge is centered around deep vein thrombosis and its use as a marker for thromboembolic complications, little is known about the natural history of both symptomatic and asymptomatic pulmonary embolism. Although differing methods of prophylaxis have shown some success, the ideal agent has yet to be discovered. The use of serial lung scanning has shown great use in the diagnosis of pulmonary embolism. Additional studies using effective diagnostic tools are needed to evaluate the risk of recurrent embolism. Only then can the duration of treatment and prophylaxis be determined. Despite the many unanswered questions, the following conclusions can be drawn: (1) fatal pulmonary emboli are a preventable complication of total joint arthroplasty; (2) fatal emboli are often preceded by small and frequently asymptomatic emboli; (3) detection and appropriate therapeutic measures for asymptomatic emboli are possible with the use of serial lung scans and judicious use of pulmonary angiography; and (4) low-dose coumadin has proven to be the most effective agent in lowering the risk of asymptomatic, symptomatic, and fatal pulmonary emboli.

The incidence of pulmonary embolism (PE) in osteoarthritic patients prophylaxed with low-dose coumadin after cemented total knee arthroplasty (TKA) was investigated prospectively. Each patient had a preoperative perfusion scan and a ventilation-perfusion scan on the seventh postoperative day. Pulmonary embolism was diagnosed by a high probability ventilation-perfusion scan or positive arteriogram. Patients with a moderate probability scan had an arteriogram to rule out PE. Pulmonary embolus was identified in 48 (5.6%) of 852 TKAs in 755 patients. Of these, six (0.7%) were symptomatic, and no fatal PE was identified. Age, gender, and weight did not show statistical differences comparing the PE and non-PE groups, nor did the incidences of previous PE, contralateral phlebitis, malignancy, and diabetes. A history of ipsilateral phlebitis increased the risk of PE from 5.2% to 13%, and a history of cardiac disease decreased the risk from 7.8% to 4.2%. Type of anesthesia, blood loss, tourniquet time, and prosthesis type were not significant factors. With the exception of previous contralateral phlebitis, traditional risk factors for PE were not found to increase risk of PE with low-dose coumadin prophylaxis. Spinal anesthesia that has been shown to be protective in total hip surgery was not a significant factor in this study.

The development of ultrasonically driven tools for revision joint arthroplasty is presented. The data represent seven-years' experience and include information from laboratory investigation and clinical experience from 20 surgical cases. Whole bone torsional strength studies reveal no decrease in strength parameters after the removal of cement ultrasonically. Comparison studies demonstrate that ultrasonic tools allow more rapid completion of cement and prosthesis removal than traditional manual tools. Histologic studies using an in vivo canine model demonstrate no deleterious effects to endosteal bone where cement had been removed by ultrasound. Clinical studies indicate that the use of ultrasound facilitates the surgery and causes no cortical perforations; the creation of cortical windows was not necessary in all cases. Ultrasound is safe and efficacious in cement and prosthesis removal during revision surgery.

This study was designed to identify those total arthroplasty patients at high risk for embolism even while on a proven warfarin prophylactic regimen and to identify the measure of anticoagulation that would be most efficacious in the prevention of pulmonary embolism (PE). A series of 2348 total arthroplasty patients had a preoperative perfusion scan and a postoperative ventilation/perfusion scan. All patients were placed on a low-dose warfarin protocol. Eighty-one patients were identified as having a PE by pulmonary arteriography (incidence of 3.4%). Of these, 89% were asymptomatic and no case was fatal. A control group of 159 patients without PE was used for comparison. Patients older than 65 years of age with a history of genitourinary infection were identified as being at higher risk of PE while on a proven warfarin prophylactic program. These patients may need additional prophylactic measures to reduce the risk of PE. In contrast, patients with a history of phlebitis, PE, obesity, or varicosities were not at excess risk for PE while on warfarin prophylaxis; therefore, no additional prophylactic measures are required. All prothrombin time profiles were within the prophylactic range. Therefore, the actual prothrombin time may not be the critical determinant of the level of anticoagulation or prophylaxis achieved.

Posterior dislocation of the prosthesis after total knee arthroplasty is an infrequent but serious complication. Seven patients with this complication were treated from January 1985 until October 1989. Five of the seven dislocations occurred in primary total knee arthroplasties and two occurred after revision arthroplasty. Limb alignment before arthroplasty, when it could be determined, was valgus in all patients, averaging 25 degrees. In each case there was an identifiable problem with the knee extensor mechanism: five had patellar dislocations, one a patellar tendon rupture, and one a patellar fracture. In three of the posterior dislocations, there was also an imbalance of the flexion and extension gaps with excessive laxity of the ligaments in flexion. Treatment was individualized. In two patients, the knee was reduced closed and the patella subsequently tracked so that no reoperation was necessary. One ruptured patellar tendon could not be repaired in a 94-year-old patient with cardiac disease. A cylinder cast was applied with poor results. Operative intervention was required in four patients, one of whom required only a patellar realignment procedure. The three other patients required component revision procedures, however, in addition to patellar realignment procedures. In these three patients, laxity of the knee in flexion was so severe that posterior instability could not be corrected merely by patellar relocation. At a follow-up examination (average, 21 months postoperatively), all six patients who were treated as recommended had good results with no further dislocations, with the exception of the one patient with a patellar tendon rupture.

Primary total knee arthroplasty was performed in four patients with acute intraarticular fractures. All four were at high risk of failure for standard operative and nonoperative treatment because of severe osteopenia, preexisting intraarticular pathology, or a limited life expectancy. All benefited by early pain relief, functional range of motion, and early ambulation, with no early perioperative morbidity.

Patellofemoral pain due to an unusual suprapatellar fibrous nodule developed in three patients after posterior stabilized total knee arthroplasty. Each patient had a "catch" or "clunk" associated with pain on extension of the knee. At revision, a prominent fibrous nodule was found at the junction of the proximal patellar pole and the quadriceps tendon. The pathogenesis of this proximal fibrous nodule may involve impingement of the anterosuperior edge of the intercondylar notch area of the femoral component into the proximal quadriceps tendon or may involve impingement of the patellar prosthesis itself on the quadriceps tendon. Roentgenographic examination revealed an abnormally proximal placement of the patellar prosthesis on the patella. Surgical removal of the fibrous nodule resolved the symptoms. Revision of the patellar prosthesis may be necessary.

A prospective, randomized study was performed in 54 female total arthroplasty patients to determine whether straight catheterization in the recovery room might reduce the incidence of postoperative urinary infection, urinary retention, and urinary catheterization. Thirty-one patients were straight catheterized in the recovery room; 23 were not. Overall, 13% of the patients developed a urinary tract infection postoperatively, 60% of the patients required at least one catheterization, and 13% of the patients required a Foley catheter. No beneficial effect of straight catheterization in the recovery room after arthroplasty was demonstrated.

Biomechanical tests of a new method of fixation for intracapsular hip fractures compared with other types of mechanical fixation were investigated under one specific loading condition. Human femora fixed in formalin were classified by the Singh index for degree of osteoporosis. Specimens of Grade III or less were grouped as osteoporotic, and Grade IV or greater, normal. Both normal and osteoporotic bones were tested. A transverse osteotomy in the subcapital region was fixed by one of two techniques: (1) Asnis screws (AS) or (2) variable length telescoping compression screws (VLCS). Each specimen was roentgenographed after fixation to assess the placement of the devices and reduction. Each femur was held in an angle vise that was placed on rollers on a table mounted on the servohydraulic testing machine. Compression was applied at a constant displacement rate of 10 mm per second to failure. Load and displacement were monitored; specimens were photographed and roentgenographed after failure. In osteoporotic bone, the VLCS provided yield and ultimate load values several times greater than those of the AS. Resistance to combined compression varus loading was significantly higher with the experimental system in osteoporotic bone. In normal bone there was no significant difference between the two systems.

Based on 21 patellar fractures after total knee arthroplasty, the authors found that nondisplaced fractures of the patella following total knee arthroplasty are best treated nonoperatively, that displaced fractures with no extensor lag can adequately be treated nonoperatively, and that displaced fractures with an extensor lag present have poor results with operative treatment. Fragment excision should be considered for displaced distal pole fractures with patellar tendon disruption, and patellectomy should be considered for failures of all other treatments.