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PubMed2003

Simultaneous revision and contralateral primary total knee arthroplasty.

BACKGROUND: There is controversy regarding whether simultaneous or staged bilateral total knee arthroplasty should be performed in patients with bilateral gonarthrosis. In addition, revision total knee arthroplasties have been less successful than primary arthroplasties. The purpose of this study was to evaluate the results of simultaneous revision and contralateral primary total knee arthroplasties performed during the same setting. METHODS: The study cohort included 150 knees in seventy-five patients who had undergone revision arthroplasty because of aseptic failure of a total knee arthroplasty and a contralateral primary arthroplasty for severe gonarthrosis under the same anesthetic. The study group was compared with a control group of sixty patients who had severe arthritis in one knee and had undergone unilateral revision total knee arthroplasty on the contralateral side. The duration of follow-up averaged five years in the group treated with the simultaneous arthroplasties and eight years in the control group. Clinical and radiographic results were evaluated with the Knee Society rating system. RESULTS: In the study group, the average knee score improved by 48 points on the side of the primary arthroplasty and by 37 points on the side of the revision. At the last follow-up visit, most (sixty-five) of the seventy-five patients stated that the knee with the revision felt better than the knee with the simultaneously performed primary arthroplasty. In the control group, the average knee score improved by 30 points on the side of the revision arthroplasty. However, forty-five of the sixty patients had a primary total knee arthroplasty on the contralateral side within two years after the index revision arthroplasty; by four years, all sixty patients had undergone a contralateral primary arthroplasty. CONCLUSIONS: We found a favorable outcome in patients who had undergone simultaneous revision and contralateral primary total knee arthroplasties. Despite a lower mean knee score and less motion, most patients seemed to prefer the knee with the revision arthroplasty to the knee with the primary procedure. These results suggest that this combined procedure is a safe and favorable alternative to a staged procedure consisting of revision and subsequent contralateral primary total knee arthroplasty.

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PubMed1997

Revision total knee arthroplasty after failed high tibial osteotomy.

Eleven patients (12 knees) who underwent revision total knee arthroplasty after failed high tibial osteotomy are reviewed. All patients were evaluated clinically and radiographically before osteotomy and arthroplasty, and in the follow-up period. The time from osteotomy until arthroplasty ranged from 9 months to 9 years, 6 months (average: 4 years, 5 months). The average follow-up period after arthroplasty was 6 years, 11 months (range: 1 year, 6 months to 13 years). On the basis of the Japan Orthopaedic Association osteoarthritic knee scoring system, the results of total knee arthroplasty after osteotomy were found to be comparable with the results after primary arthroplasty. Patients were divided into two groups according to the time from osteotomy to arthroplasty, alignment of the leg before arthroplasty, and the reason for requiring revision arthroplasty. Group 1 included 6 patients with 6 knees who underwent arthroplasty within 3 years after osteotomy. The main reason for revision arthroplasty in Group 1 was pain due to the recurrence of a varus deformity. Group 2 included 5 patients (6 knees) who underwent revision arthroplasty more than 5 years after osteotomy. The main reason for revision arthroplasty in Group 2 was pain or hydrarthrosis due to the progression to bi-compartmental or tri-compartmental osteoarthritis. There was no significant difference in the clinical results between the two groups. Concerning patellar height, LT/LP of Group 1 was significantly lower than that of Group 2. There were no significant differences in the radiographic findings among the two study groups and the control group of 71 patients (110 knees) who underwent primary total knee arthroplasty, except for alignment before arthroplasty. Using the Japan Orthopaedic Association osteoarthritic knee scoring system, previous osteotomy does not seem to affect the outcome of total knee arthroplasty. With refinement of the technique of high tibial osteotomy, revision total knee arthroplasty after 3 years or less would be avoidable, however, revision total knee arthroplasty due to osteoarthritic deterioration over time would be inevitable.

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PubMed2006

Outcomes of total and unicompartmental knee arthroplasty for secondary and spontaneous osteonecrosis of the knee.

BACKGROUND: The reported outcomes of patients who underwent total or unicompartmental knee arthroplasty for secondary and spontaneous osteonecrosis of the knee are often from studies that lack the number of subjects necessary to generate meaningful conclusions. We systematically reviewed the available literature in order to define the outcomes of patients after total knee arthroplasty for secondary osteonecrosis and after total or unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee. METHODS: A literature review yielded twenty cohorts with demographic patient information and outcome scores (global knee scores, radiographic outcomes, and revision rates) for patients who had knee arthroplasty as treatment for either secondary or spontaneous osteonecrosis of the knee. The mean preoperative and postoperative global knee scores, the mean revision rate, and the categorization of the mean "poor" and mean "good" outcomes for the knees with each underlying disease were tabulated and reported. The demographic data and the reported mean global knee scores were weighted by the number of knees in each study. RESULTS: Total knee arthroplasty was performed in 150 knees with secondary osteonecrosis and 148 knees with spontaneous osteonecrosis, and unicompartmental knee arthroplasty was performed in sixty-four knees with spontaneous osteonecrosis. Total knee arthroplasty for spontaneous osteonecrosis of the knee was associated with the best outcomes (higher "good" and postoperative global knee scores and lower revision [3%] and "poor" outcome [6%] rates compared with the other two groups). The outcomes after total knee arthroplasty in knees with secondary osteonecrosis as well as in knees with spontaneous osteonecrosis were better in the cohorts operated on during or after 1985 than in those operated on before 1985. Similarly, the outcomes after unicompartmental knee arthroplasty in knees with spontaneous osteonecrosis of the knee were also better in the cohorts operated on during or after 1985 than in those operated on before 1985. CONCLUSIONS: Total knee arthroplasty performed as treatment for either secondary osteonecrosis or spontaneous osteonecrosis and unicompartmental knee arthroplasty performed as treatment for spontaneous osteonecrosis were associated with improved outcomes in cohorts with more recent operative dates. The evidence suggests that the use of contemporary cemented implants in total knee arthroplasty and the selective use of stems and augments in patients who have development of secondary osteonecrosis after total knee arthroplasty are producing outcomes that are comparable to those seen after total knee arthroplasty for osteoarthritis. Although the outcomes of patients who have total knee arthroplasty for the treatment of spontaneous osteonecrosis of the knee have historically been favorable, such outcomes have also shown particular improvement in the studies from more recent operative periods. Although poor outcomes were seen after unicompartmental knee arthroplasty in earlier studies of patients with spontaneous osteonecrosis of the knee, it is possible that those results were secondary to inappropriate patient selection, as the authors of the most recent and, to our knowledge, the only study to follow established operative indications regarding the use of unicompartmental knee arthroplasty reported excellent results. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

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PubMed2006

Cost-effectiveness of unicompartmental and total knee arthroplasty in elderly low-demand patients. A Markov decision analysis.

BACKGROUND: Interest in unicompartmental knee arthroplasty has recently increased in the United States, making a firm understanding of the indications for this procedure important. The purpose of this study was to examine the cost-effectiveness of unicompartmental knee arthroplasty compared with total knee arthroplasty in elderly low-demand patients. METHODS: A Markov decision model was used to evaluate the cost-effectiveness of unicompartmental knee arthroplasty as compared with total knee arthroplasty in the elderly population. Transition probabilities were estimated from the Norwegian Arthroplasty Register and the arthroplasty literature, and costs were based on the average Medicare reimbursement for unicompartmental, tricompartmental, and revision knee arthroplasties. Outcomes were measured in quality-adjusted life-years. RESULTS: Our model showed unicompartmental knee arthroplasty to be a cost-effective strategy for this population as long as the annual probability of revision is <4%. The cost of unicompartmental knee arthroplasty must be greater than $13,500 or the cost of total knee arthroplasty must be less than $8500 before total knee arthroplasty becomes more cost-effective. CONCLUSIONS: Our model suggests that, on the basis of currently available cost and outcomes data, unicompartmental knee arthroplasty and total knee arthroplasty have similar cost-effectiveness profiles in the elderly low-demand patient population. However, several important parameters that could alter the cost-effectiveness analysis were identified; these included implant survival rates, costs, perioperative mortality and infection rates, and utility values achieved with each procedure. The thresholds identified in this study may help decision-makers to evaluate the cost-effectiveness of each strategy as further research characterizes the variables associate with unicompartmental and total knee arthroplasties and may be helpful for designing future appropriate clinical trials.

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PubMed1996

Cancer risk after metal on metal and polyethylene on metal total hip arthroplasty.

The incidence of cancer after metal on metal total hip arthroplasty (McKee-Farrar) and polyethylene on metal total hip arthroplasty (Brunswik, Lubinus) was compared with that of the general population in Finland. The mean followup time for the patients who had metal on metal total hip arthroplasty was 15.7 (9092 person years) and for the patients who had polyethylene on metal total hip arthroplasty it was 12.5 years (19,846 person years). One hundred thirteen malignant cancers were observed in patients who had metal on metal total hip arthroplasty and 212 were observed in patients who had polyethylene on metal total hip arthroplasty. The standardized incidence ratio for all cancers of the metal on metal arthroplasty group was 0.95 (95% confidence limits 0.79-1.13) and that of the polyethylene on metal arthroplasty group was 0.76 (95% confidence limits 0.68-0.86). The risk of total cancer in the patients who had metal on metal total hip arthroplasty was 1.23-fold compared with that of the patients who had polyethylene on metal total hip arthroplasty. Both groups had significantly less lung cancer than the general population: the leukemia incidence in the patients who had metal on metal total hip arthroplasty was slightly increased (observed to experienced 7/3.03, standardized incidence ratio 0.61; 95% confidence limits 0.17-1.56). The leukemia rate of the patients who had metal on metal total hip arthroplasty was 3.77-fold compared with that of the patients who had polyethylene on metal total hip arthroplasty, but this difference was not statistically significant. No sarcomas were observed at the site of the prosthesis. The incidence of the other forms of cancers did not differ significantly from those in the general population. The observed variation in the incidence of different cancers among patients who had total hip arthroplasty compared with the general population suggests that factors other than total hip arthroplasty play a major role in the origin of cancer.

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PubMed2005

Racial/ethnic differences in surgical outcomes in veterans following knee or hip arthroplasty.

OBJECTIVE: The utilization of joint arthroplasty for knee or hip osteoarthritis varies markedly by patient race/ethnicity. Because of concerns about surgical risk, black patients are less willing to consider this treatment. There are few published race/ethnicity-specific data on joint arthroplasty outcomes. The present study was undertaken to examine racial/ethnic differences in mortality and morbidity following elective knee or hip arthroplasty. METHODS: Using information from the Veterans Administration National Surgical Quality Improvement Program database, data on 12,108 patients who underwent knee arthroplasty and 6,703 patients who underwent hip arthroplasty over a 5-year period were analyzed. Racial/ethnic differences were determined using prospectively collected data on patient characteristics, procedures, and short-term outcomes. The main outcome measures were risk-adjusted 30-day mortality and complication rates. RESULTS: Adjusted rates of both non-infection-related and infection-related complications after knee arthroplasty were higher among black patients compared with white patients (relative risk [RR] 1.50, 95% confidence interval [95% CI] 1.08-2.10 and RR 1.42, 95% CI 1.06-1.90, respectively). Hispanic patients had a significantly higher risk of infection-related complications after knee arthroplasty (RR 1.64, 95% CI 1.08-2.49) relative to otherwise similar white patients. Race/ethnicity was not significantly associated with the risk of non-infection-related complications (RR 0.97, 95% CI 0.68-1.38 in blacks; RR 1.18, 95% CI 0.60-2.30 in Hispanics) or infection-related complications (RR 1.27, 95% CI 0.91-1.78 in blacks; RR 1.22, 95% CI 0.63-2.36 in Hispanics) after hip arthroplasty. The overall 30-day mortality was 0.6% following knee arthroplasty and 0.7% following hip arthroplasty, with no significant differences by race/ethnicity observed for either procedure. CONCLUSION: Although absolute risks of complication are low, our findings indicate that, after adjustment, black patients have significantly higher rates of infection-related and non-infection-related complications following knee arthroplasty, compared with white patients. In addition, adjusted rates of infection-related complications after knee arthroplasty are higher in Hispanic patients than in white patients. Such differences between ethnic groups are not seen following hip arthroplasty. These groups do not appear to differ significantly in terms of post-arthroplasty mortality rates.

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PubMed1997

Simultaneous bilateral versus unilateral total knee arthroplasty. Outcomes analysis.

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.

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PubMed2002

The effect of education and income on need and willingness to undergo total joint arthroplasty.

OBJECTIVE: Individuals with lower socioeconomic status (SES) receive less arthritis care, including joint arthroplasty. However, no studies have considered the expectations or needs of the patients. Our objective was to assess the effect of education and income on the potential need for, and the willingness to consider hip and knee arthroplasty. METHODS: Through a mail/telephone survey of 48,218 persons ages 55 years or older residing in 2 areas of Ontario, Canada, 3,307 individuals with moderate-to-severe hip/knee problems were identified. These individuals received a questionnaire to assess education, income, arthritis severity, and comorbidity. In a subset of these subjects, we conducted interviews to evaluate the willingness to consider arthroplasty, and we also performed clinical and radiographic examinations of the joints to validate self-reports of arthritis. The potential need for arthroplasty was defined as the presence of severe arthritis (as scored by the Western Ontario and McMaster Universities Osteoarthritis Index), with no absolute contraindications to surgery. Separate logistic regression models examined the independent effects of education and income on the potential need for, and definite willingness to consider arthroplasty, after controlling for age, sex, and region of residence. Potential unmet need was estimated as the proportion of subjects with the need for arthroplasty who were not already on a surgery waiting list, who were definitely willing to consider arthroplasty, and who had evidence of arthritis by examination and radiography. RESULTS: Response rates were at least 72% for all questionnaires and interviews. Less education (adjusted odds ratio [OR] 1.57 for less than high school versus postsecondary education, 95% confidence interval [95% CI] 1.17-2.11) and lower income (adjusted OR 1.83 for </=$20,000 versus >$40,000, 95% CI 1.24-2.70) were independently associated with a greater likelihood of having the potential need for arthroplasty. Among the subjects with potential need, neither education nor income was independently associated with a definite willingness to consider arthroplasty. Thus, taking willingness into consideration, individuals with less education and/or lower income were more likely to have potential unmet need for arthroplasty. CONCLUSION: Persons with lower SES had a greater need for, and were equally willing to consider arthroplasty, compared with those with higher SES. Thus, observed SES disparities in the rates of performed arthroplasties cannot be explained by a lower need or less willingness to undergo arthroplasty in those with lower SES.

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PubMed2003

Intrathecal morphine for postoperative analgesia: a randomized, controlled, dose-ranging study after hip and knee arthroplasty.

UNLABELLED: In this series, we examined analgesia and side effects of intrathecal morphine sulfate (ITMS) after hip and knee arthroplasty over a dose range of 0.0-0.3 mg. Eighty patients undergoing hip (n = 40) or knee (n = 40) arthroplasty were randomized to receive ITMS (0.0, 0.1, 0.2, or 0.3 mg). A patient-controlled analgesia (PCA) device provided free access to additional analgesics. Morphine use, pain relief, and side effects were recorded for 24 h. Data were analyzed with analysis of variance and linear regression. After hip arthroplasty, morphine use was less in patients receiving 0.1, 0.2, or 0.3 mg of ITMS than in control patients (P < 0.05). After knee arthroplasty, ITMS did not reduce postoperative morphine requirements. Nausea and vomiting and the incidence of oxygen saturation <93% were similar in all groups. Pruritus was more common after ITMS. Patients receiving 0.2 or 0.3 mg of ITMS were more satisfied with their pain control than those receiving 0.0 or 0.1 mg after both hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than after hip arthroplasty. We conclude that combining small-dose (0.2 mg) ITMS with PCA morphine provides good to excellent pain control in most patients after total hip or knee arthroplasty. However, PCA morphine use was reduced by the addition of ITMS only after hip arthroplasty. IMPLICATIONS: This series examined the need for supplemental analgesics, the quality of analgesia, and the incidence of side effects with intrathecal morphine sulfate (ITMS) for analgesia after hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than hip arthroplasty. Combining small-dose (0.2 mg) ITMS with standard doses of PCA morphine provided good to excellent pain control in most patients and reduced patient-controlled analgesia morphine use after hip, but not knee, arthroplasty.

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PubMed2007

Factors associated with prolonged wound drainage after primary total hip and knee arthroplasty.

BACKGROUND: Prolonged wound drainage following total hip or total knee arthroplasty has been associated with an increased risk of postoperative morbidity. The purpose of this study was to determine the pharmacologic, surgical, and patient-specific factors that are associated with prolonged wound drainage and the relationship of this complication to the length of hospital stay and the rate of wound infections. METHODS: We conducted a retrospective observational study of 1211 primary total hip arthroplasties and 1226 primary total knee arthroplasties. Prospectively collected data included body mass index, intraoperative blood loss, surgical time, type of prophylaxis against deep venous thrombosis, and length of hospital stay. The association of these factors with the duration of postoperative wound drainage was analyzed. An acute infection developed after fifteen primary total hip arthroplasties and ten primary total knee arthroplasties. The patients with an acute postoperative infection were compared with their uninfected counterparts, and an odds ratio was determined to estimate the risk of prolonged wound drainage resulting in a wound infection. RESULTS: Morbid obesity was strongly associated with prolonged wound drainage in the total hip arthroplasty group (p = 0.001) but not in the total knee arthroplasty group (p = 0.590). An increased volume of drain output was an independent risk factor for prolonged wound drainage in both groups. Patients who received low-molecular-weight heparin for prophylaxis against deep venous thrombosis had a longer time until the postoperative wound was dry than did those treated with aspirin and mechanical foot compression or those who received Coumadin (warfarin); this difference was significant on the fifth postoperative day (p = 0.003) but not by the eighth postoperative day. Prolonged wound drainage resulted in a significantly longer hospital stay in both groups (p < 0.001). Each day of prolonged wound drainage increased the risk of wound infection by 42% following a total hip arthroplasty and by 29% following a total knee arthroplasty. CONCLUSIONS: Morbid obesity, the use of low-molecular-weight heparin, and a higher drain output were associated with a prolonged time until the postoperative wound was dry following a primary total hip arthroplasty, whereas a higher drain output was the only risk factor associated with prolonged drainage following a primary total knee arthroplasty. Prolonged drainage was associated with a higher rate of infection following a primary total hip arthroplasty, whereas obesity was the only identified independent risk factor for postoperative infection following a primary total knee arthroplasty.

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PubMed2006

Prevalence and risk factors for symptomatic thromboembolic events after shoulder arthroplasty.

UNLABELLED: Deep venous thrombosis and pulmonary embolism after shoulder arthroplasty are not well described. We sought to identify the frequency of deep venous thrombosis and pulmonary embolisms in patients after shoulder arthroplasties to compare these rates with the frequency of deep venous thrombosis and pulmonary embolisms among patients who had total hip and total knee arthroplasties, and to identify associated risk factors. The New York State Department of Health Statewide Planning and Research Cooperative System database was used to identify hospital admissions of patients having shoulder, hip, or knee arthroplasties between 1985 and 2003 with or without an associated diagnostic code for deep venous thrombosis or pulmonary embolism. This resulted in a retrospective cohort of 328,301 procedures. The frequency of deep venous thrombosis was 5.0 per 1000 procedures for shoulder arthroplasties compared with 15.7 for hip arthroplasties and 26.9 for knee arthroplasties. The frequency of pulmonary embolisms was 2.3 for shoulder arthroplasties, 4.2 for hip arthroplasties, and 4.4 for knee arthroplasties. Increasing age, trauma, and cancer were risk factors for thromboembolic events after shoulder arthroplasties. Although the absolute rates of thromboembolic complications were less in patients who had shoulder arthroplasties compared with those of patients who had lower extremity procedures, a larger percentage of these complications were pulmonary embolisms. Perioperative antithrombotic prophylaxis may be beneficial to reduce the frequency of deep venous thrombosis and pulmonary embolisms among patients having shoulder arthroplasties, particularly in higher-risk groups. LEVEL OF EVIDENCE: Prognostic study, Level II (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

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PubMed1999

Analysis of routine histological evaluation of tissues removed during primary hip and knee arthroplasty.

BACKGROUND: It has often been hospital policy to send all resected specimens obtained during a total hip or knee arthroplasty for histological evaluation. This practice is expensive and may be unnecessary. We sought to determine the ability of surgeons to diagnose primary joint conditions correctly, and we attempted to identify any possible risks to the patient resulting from the omission of routine histological evaluation of specimens at the surgeon's discretion. Our objective was to ascertain whether routine histological evaluation could be safely omitted from the protocol for primary hip and knee arthroplasty without compromising the care of the patient. METHODS: A total of 1388 consecutive arthroplasties in 1136 patients were identified from a database of primary total hip and knee arthroplasties that was prospectively maintained by the senior one of us. Follow-up data obtained at a mean of 5.5 years (range, two to ten years) were available after 92 percent (1273) of the 1388 arthroplasties. The preoperative diagnosis was determined from the history, findings on clinical examination, and radiographs. The intraoperative diagnosis was determined by gross inspection of joint fluid, articular cartilage, synovial tissue, and the cut surfaces of resected specimens. The combination of the preoperative and intraoperative diagnoses was considered to be the surgeon's clinical diagnosis. All resected specimens were sent for routine histological evaluation, and a pathological diagnosis was made. Attention was given to whether a discrepancy between the surgeon's clinical diagnosis and the pathological diagnosis altered the management of the patient. The original diagnoses were updated with use of annual radiographs and clinical assessments. The cost of histological examination of specimens obtained at arthroplasty was determined by consultation with hospital administration, accounting, and pathology department personnel. RESULTS: A pathological fracture or an impending fracture was diagnosed preoperatively and confirmed intraoperatively during twelve of the 1388 arthroplasties. Histological analysis demonstrated malignancy in specimens obtained during eleven of these arthroplasties and evidence of a benign rheumatoid geode in the specimen obtained during the twelfth arthroplasty. The preoperative and intraoperative diagnoses made before and during the remaining 1376 arthroplasties were benign conditions, which were confirmed histologically in all patients. No diagnosis changed during the follow-up period. As demonstrated by a comparison with the histological diagnosis, the surgeon's clinical diagnosis of malignancy had a sensitivity of 100 percent (95 percent confidence interval, 74.0 to 100 percent), a specificity of 99.9 percent (95 percent confidence interval, 99.6 to 100 percent), a positive predictive value of 91.7 percent (95 percent confidence interval, 64.6 to 98.5 percent), and a negative predictive value of 100 percent (95 percent confidence interval, 99.7 to 100 percent). There was a discrepancy between the preoperative and intraoperative diagnoses associated with eleven arthroplasties. All eleven intraoperative diagnoses were correct, as confirmed histologically. Excluding the patients who had a pathological or impending fracture, the accuracy of the surgeon's preoperative diagnosis was 99.2 percent (95 percent confidence interval, 98.6 to 99.5 percent). When the intraoperative and preoperative diagnoses were combined, the accuracy was 100 percent (95 percent confidence interval, 99.7 to 100 percent). Histological evaluation at our hospital resulted in total charges, including hospital costs and professional fees, of $196.27 and a mean total reimbursement of $102.59 per evaluation. In our series of 1136 patients with 1388 arthroplasties, these costs could have been eliminated for all but the twelve patients who had a suspected malignant lesion and the one patient in whom pigmented villonodular synovitis was found. (ABSTRACT

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