Charlotte B. Phillips

Outcomes of total hip and knee replacement: Preoperative functional status predicts outcomes at six months after surgery

OBJECTIVE To determine whether patients with knee or hip osteoarthritis (OA) who have worse physical function preoperatively achieve a postoperative status that is similar to that of patients with better preoperative function. METHODS This study surveyed an observational cohort of 379 consecutive patients with definite OA who were without other inflammatory joint diseases and were undergoing either total hip or knee replacement in a US (Boston) and a Canadian (Montreal) referral center. Questionnaires on health status (the Short Form 36 and Western Ontario and McMaster Universities Osteoarthritis Index) were administered preoperatively and at 3 and 6 months postoperatively. Physical function and pain due to OA were deemed the most significant outcomes to study. RESULTS Two hundred twenty-two patients returned their questionnaires. Patients in the 2 centers were comparable in age, sex, time to surgery, and proportion of hip/knee surgery. The Boston group had more education, lower comorbidity, and more cemented knee prostheses. Patients undergoing hip or knee replacement in Montreal had lower preoperative physical function and more pain than their Boston counterparts. In patients with lower preoperative physical function, function and pain were not improved postoperatively to the level achieved by those with higher preoperative function. This was most striking in patients undergoing total knee replacement. CONCLUSION Surgery performed later in the natural history of functional decline due to OA of the knee, and possibly of the hip, results in worse postoperative functional status.

Rates and Outcomes of Primary and Revision Total Hip Replacement in the United States Medicare Population

Background: Information on the epidemiology of primary total hip replacement is limited, and we are not aware of any reports on the epidemiology of revision total hip replacement. The objective of this study was to characterize the rates and immediate postoperative outcomes of primary and revision total hip replacement in persons sixty-five years of age and older residing in the United States.Methods: We used Medicare claims submitted by hospitals, physicians, and outpatient facilities between July 1, 1995, and June 30, 1996, to identify individuals who had undergone elective primary total hip replacement for a reason other than a fracture (61,568 patients) or had had revision total hip replacement (13,483 patients). Annual incidence rates of primary and revision total hip replacement were calculated, and multivariate modeling was used to evaluate the association between patient characteristics and surgical rates. The rates of occurrence of five complications within ninety days postoperatively were also evaluated, and relationships between those outcomes and patient characteristics were assessed with use of multivariate models adjusted for hospital and surgeon volume.Results: The rates of primary total hip replacement were three to six times higher than the rates of revision total hip replacement. Women had higher rates than men, and whites had higher rates than blacks. The rates of primary and revision total hip replacement increased with age until the age of seventy-five to seventy-nine years and then declined. The rates of complications occurring within ninety days after primary total hip replacement were 1.0% for mortality, 0.9% for pulmonary embolus, 0.2% for wound infection, 4.6% for hospital readmission, and 3.1% for hip dislocation. The rates after revision total hip replacement were 2.6%, 0.8%, 0.95%, 10.0%, and 8.4%, respectively. Factors associated with an increased risk of an adverse outcome included increased age, gender (men were at higher risk than women), race (blacks were at higher risk than whites), a medical comorbidity, and a low income.Conclusions: Analysis of United States Medicare population data showed that the rates of total hip replacement increased with age up to the age of seventy-five to seventy-nine years and that blacks had a significantly lower rate of total hip replacement than whites. The overall rates of adverse outcomes were relatively low, but they were significantly higher after revision than after primary total hip replacement.Level of Evidence: Prognostic study, Level II-1 (retrospective study). See p. 2 for complete description of levels of evidence.

Association Between Hospital and Surgeon Procedure Volume and Outcomes of Total Hip Replacement in the United States Medicare Population

Background: The mortality and complication rates of many surgical procedures are inversely related to hospital procedure volume. The objective of this study was to determine whether the volumes of primary and revision total hip replacements performed at hospitals and by surgeons are associated with rates of mortality and complications. Methods: We analyzed claims data of Medicare recipients who underwent elective primary total hip replacement (58,521 procedures) or revision total hip replacement (12,956 procedures) between July 1995 and June 1996. We assessed the relationship between surgeon and hospital procedure volume and mortality, dislocation, deep infection, and pulmonary embolus in the first ninety days postoperatively. Analyses were adjusted for age, gender, arthritis diagnosis, comorbid conditions, and income. Analyses of hospital volume were adjusted for surgeon volume, and analyses of surgeon volume were adjusted for hospital volume. Results: Twelve percent of all primary total hip replacements and 49% of all revisions were performed in centers in which ten or fewer of these procedures were carried out in the Medicare population annually. In addition, 52% of the primary total hip replacements and 77% of the revisions were performed by surgeons who carried out ten or fewer of these procedures annually. Patients treated with primary total hip replacement in hospitals in which more than 100 of the procedures were performed per year had a lower risk of death than those treated with primary replacement in hospitals in which ten or fewer procedures were performed per year (mortality rate, 0.7% compared with 1.3%; adjusted odds ratio, 0.58; 95% confidence interval, 0.38, 0.89). Patients treated with primary total hip replacement by surgeons who performed more than fifty of those procedures in Medicare beneficiaries per year had a lower risk of dislocation than those who were treated by surgeons who performed five or fewer of the procedures per year (dislocation rate, 1.5% compared with 4.2%; adjusted odds ratio, 0.49; 95% confidence interval, 0.34, 0.69). Patients who had revision total hip replacement done by surgeons who performed more than ten such procedures per year had a lower rate of mortality than patients who were treated by surgeons who performed three or fewer of the procedures per year (mortality rate, 1.5% compared with 3.1%; adjusted odds ratio, 0.65; 95% confidence interval, 0.44, 0.96). Conclusions: Patients treated at hospitals and by surgeons with higher annual caseloads of primary and revision total hip replacement had lower rates of mortality and of selected complications. These analyses of Medicare claims are limited by a lack of key clinical information such as operative details and preoperative functional status.

Comparative measurement sensitivity of short and longer health status instruments.

Short measures of health status are used increasingly in health services research, yet their sensitivities to clinical change have not been compared with longer, established instruments. In this study, 5 health status measures were administered preoperatively and 3 months postoperatively to 54 patients undergoing total hip arthroplasty. These instruments included the Sickness Impact Profile (SIP)—an established, long measure—and 4 short forms: the SF-36, Functional Status Questionnaire, shortened Arthritis Impact Measurement Scales, and Modified Health Assessment Questionnaire. Scores for physical, psychological, and global dimensions were constructed by aggregating subscales. Sensitivity to change, or responsiveness, was expressed with the standardized response mean (SRM), calculated as the mean change in score divided by the standard deviation of the change in score. The sampling distribution of the SRM was estimated with a jackknife procedure. Preoperative scores were moderately to highly correlated across instruments. The physical and global dimension SRMs of the brief health status measures ranged from 0.85 to 1.27 and were as large as or larger than the corresponding SIP SRMs. The SIP had the highest SRM on the psychological dimension. None of the instruments was significantly more sensitive than the others at the critical value (P = 0.005) adjusted for multiple comparisons. The brief health status measures were equally or more responsive than the SIP after total hip arthroplasty in the physical and global dimensions. Much larger samples are required to demonstrate statistically significant differences in SRMs among instruments.

Incidence rates of dislocation, pulmonary embolism, and deep infection during the first six months after elective total hip replacement.

Background: The lengths of acute hospital stays following total hip replacement have diminished substantially in recent years. As a result, a greater proportion of complications occurs following discharge. Data on the incidence trends of major complications of total hip replacement would facilitate recognition and management of these adverse events.Methods: We used Medicare claims data on beneficiaries sixty-five years and older who had had elective, primary total hip replacement for a reason other than a fracture (58,521 patients) or had had revision total hip replacement (12,956 patients) between July 1, 1995, and June 30, 1996. We calculated incidence rates of dislocation, pulmonary embolism, and deep hip infection per 10,000 person-weeks for four time-periods following the admission for the surgery (during the index hospitalization, from discharge to four weeks postoperatively, from five to thirteen weeks postoperatively, and from fourteen to twenty-six weeks postoperatively). We then used life-table methods to estimate the cumulative incidence of each complication over the first six postoperative months.Results: Of the patients who had had a primary total hip replacement, 3.9% had a dislocation, 0.9% had a pulmonary embolism, and 0.2% had a deep infection in the first twenty-six postoperative weeks. In the revision total hip replacement cohort, the proportions with dislocation, pulmonary embolism, and deep infection were 14.4%, 0.8%, and 1.1%, respectively. The rates of these adverse outcomes were highest during the index hospitalization, diminished considerably in the period from discharge to four weeks postoperatively, and continued to drop in the periods from five to thirteen and fourteen to twenty-six weeks postoperatively.Conclusions: The incidence rates of dislocation, pulmonary embolism, and deep infection are highest immediately after total hip replacement, but they continue to be elevated throughout the first three postoperative months. With the lengths of hospital stays continuing to diminish, an increasing proportion of complications will occur in outpatients. These findings provide a basis for developing strategies to prevent these complications in the postdischarge management of patients who have had elective total hip replacement.Level of Evidence: Prognostic study, Level II-1 (retrospective study). See p. 2 for complete description of levels of evidence.

The long-term clinical outcomes of Lyme disease. A population-based retrospective cohort study.

Lyme borreliosis is a tick-borne infection caused by the spirochete Borrelia burgdorferi [1-3]. The disease usually begins with erythema migrans accompanied by viral-like or meningitis-like symptoms. Weeks later meningitis, facial palsy, atrioventricular nodal block, or migratory musculoskeletal pain may develop, followed months to years later by episodes of frank arthritis, encephalopathy, polyneuropathy, or acrodermatitis [4]. Lyme disease is now the most common vector-borne disease in the United States; nearly 50 000 patients have been diagnosed with it since 1982 [5]. Musculoskeletal and neurologic sequelae may occur from Lyme disease. Some of the late consequences of Lyme disease, such as oligoarticular arthritis, axonal polyneuropathy, or active encephalopathy, are thought to be caused by persistent spirochetal infection and are amenable to antibiotic treatment [6-8]. Other syndromes such as persistent arthritis, fibromyalgia, subtle joint pain, or mild encephalopathy do not improve with antibiotic treatment, suggesting a mechanism other than active infection [9-12]. We studied persons residing in an endemic coastal area of Massachusetts who were previously infected with B. burgdorferi in the early 1980s [13]. They contracted Lyme disease while the clinical syndromes and optimal antibiotic therapies were still evolving, which offered a natural experiment for the identification of risk factors for Lyme disease sequelae. We ascertained the prevalence of persistent symptoms in unselected patients with a history of Lyme disease; ascertained their rheumatologic, neurologic, and health status outcomes; and identified potential risk factors for these long-term sequelae. Methods Participants In February l991, we did a follow-up analysis of residents of Argylla Road in Ipswich, Massachusetts, an endemic coastal area for Lyme disease. The incidence and clinical course of Lyme disease among residents of this area have been reported previously [13]. Participants were recruited by calling consecutive households located in the Argylla Road area, the epicenter of infection, to ask if they would be interested in enrolling in a study about Lyme disease in their area. Potential participants were told that the study involved a history, physical examination, and serologic analysis for Lyme disease. Information about whether a person ever had a previous diagnosis of Lyme disease was obtained and used to assign tentative status (with or without Lyme disease) for study participants. We recruited participants until we had 50 tentative persons with Lyme disease and 50 tentative controls. Once the potential Lyme disease group was filled, calls were made consecutively to fill the potential control group. Residents 18 years of age or older were invited to participate in the study. This protocol was approved by the Brigham & Womens Hospital Committee for the Protection of Human Subjects. Confirmation of Lyme Disease For inclusion in the Lyme group, persons needed a previous diagnosis of Lyme disease by a physician and needed to fulfill the Centers for Disease Control and Prevention (CDC) criteria for Lyme disease (a history of physician-documented erythema migrans or a late manifestation of Lyme disease confirmed by a positive Lyme serologic test result, or both [14]). This information was obtained through patient interview and then medical record review to determine if patients fulfilled criteria for Lyme disease. Previous study records, local physician reports, and previous serologic test results were available for confirmation of Lyme disease. Persons without a previous clinical history of Lyme disease were classified as controls. The status of the participants (with or without Lyme disease) was determined independent of the clinical assessment, using a protocol that did not include any outcome data. Assessment of Clinical Outcomes A blinded investigator determined outcomes in a standardized manner independent of Lyme disease status. All patients completed a standardized questionnaire, had electrocardiography, and had a neuropsychological battery of tests. The questionnaire included data on demographics, comorbidity, education, review of systems, medications, memory and cognitive function, and the Short Form-36 health status measure (a reliable, previously validated measure of physical, psychological, social, and role functions [15]). A physical examination was done by one observer blinded to Lyme disease status. It included a joint examination (the American College of Rheumatology Glossary examination) that measured swelling and pain through passive range of motion [16] and a neurologic evaluation of strength and deep tendon reflexes, light touch, and vibration sensation with a 128-Hz tuning fork (at the elbow, wrist, fibula, and ankles). Pain and swelling indices from the joint examination (the American College of Rheumatology Glossary examination) were summed and recorded as a global score. A vibration test result of a distal gradient was considered present if the participant reported diminished vibratory sensation at a distal compared with proximal site. Each participant had an electrocardiographic study that was interpreted blindly by a cardiologist uninvolved with the clinical assessment. All outcomes were determined by one investigator who had no knowledge of whether participants were in the Lyme or control groups. The neuropsychological battery of tests measured immediate and delayed verbal memory, attention, conceptualization, fine motor dexterity, and perceptual discrimination. Tests included the California Verbal Learning Test [17], Wechsler Memory Scale (visual reproduction and verbal paired associates subtests [18]), Shipley abstraction subtest [19], Stroop test [20], Trailmaking test [21], and Purdue Pegboard Test [22]. The California Verbal Learning Test measures verbal memory. Participants are asked to learn a list of 16 words during five trials; recall on the fifth trial is recorded (trial 5). This is then followed by a distracter list. The original list is recalled after the distracter list is learned (short recall) and then recalled again after a 20-minute delay (long recall). This is a challenging test of memory for patients with superior premorbid experience. Normative values are available for young and elderly adults [17]; the range of normal is between 11 and 15 words for trial 5 and is between 10 and 15 words for the long-recall subtest for persons between 45 and 54 years of age. A clinically significant change in the California Verbal Learning Test would be recalling 4 more words or 4 fewer words. All tests were administered according to published procedures. Test scores were transformed into standard scores calculated from published, age-corrected normative data. Participants with a score of 2 or more SDs from age-adjusted means were considered impaired. All results were reviewed by a neuropsychologist (RK) who was not involved with the participants evaluation, to determine those patients who were in need of further clinical evaluation. Participants with swelling or pain (joint examination test result), evidence of a distal gradient (vibration test result) or persistent symptoms of paresthesias in an extremity, or impairment on two or more neurocognitive tests were sent for further clinical evaluation. Nine patients were evaluated at the Lyme disease clinic at Tufts-New England Medical Center and 4 were evaluated by other neurologist or rheumatologist consultants to determine if these abnormal screening test results were accompanied by objective findings. This evaluation included lumbar puncture, electrophysiologic studies, magnetic resonance imaging, detailed neuropsychological tests [8], joint radiographs, or arthrocentesis. Serologic Evaluation All patients had serologic testing after the history and examination. Serum samples were stored at 70C and were tested for IgG antibodies to B. burgdorferi by indirect enzyme-linked immunosorbent assay (ELISA [23]); for IgM, IgG, and IgA antibodies to the spirochete by antibody-capture enzyme immunoassays [24]; and for the pattern of IgG reactivity to spirochetal polypeptides by Western blotting. In general, Western blot reactivity varied with the degree and duration of dissemination of Lyme disease. For example, patients with early localized infection or erythema migrans might react to only 2 to 8 B. burgdorferi polypeptides, those with meningitis might react to at least 8 to 14 polypeptides, and those with arthritis or late central nervous system disease might react to as many as 18 to 25 polypeptides (Berardi VP. Personal communication). The isolate used for antigen preparations was the B. burgdorferi G39/40 strain obtained through low passage [24]. Indirect ELISA titers greater than 400 and ELISA capture ratios (sample optical density/control optical density) of 1.0 or more were considered as increased test results. Western blot reactivity to five or more B. burgdorferi-specific polypeptides indicated previous infection [25]. Silver Stain Method The Dieterle silver impregnation stain used was a modification made by one of us (PHD) in 1985 [26]. This standard approach has yielded a constant clean yellow background of cerebral cortex sections with no silver impregnation of anatomic neural processes and dendrites. Spirochetes are easily seen as black to blue-black cells against the yellow tissue. Specificity for nonstaining of normal tissue fibers (procollagen, elastin, basement membrane material, and neural dendrites and filaments) and documentation of the cytologic structure of Borrelia spirochete strains were further tested in a large extended study [27]. Controls routinely used in each stain assay consisted of NP40 strain that was injected into human normal breast tissue removed for cosmetic surgery and was paraffin-embedded in the usual manner (negative control), and rat gonad tissue infected with the Reiter strain of treponemal spirochetes (positive c

American Burn Association/Shriners Hospitals for Children burn outcomes questionnaire: construction and psychometric properties

To develop a standardized, practical, self-administered questionnaire to monitor pediatric patients with burns and to evaluate the effectiveness of comprehensive pediatric burn management treatments, a group of experts generated a set of items to measure relevant burn outcomes. Children between the ages of 5 and 18 years were assessed in a cross-sectional study. Both parent and adolescent responses were obtained from children 11 to 18 years old. The internal reliability of final scales ranged from 0.82 to 0.93 among parents and from 0.75 to 0.92 among adolescents. Mean differences between parent and adolescent were small; the greatest difference occurred in the appearance subscale. Parental scales showed evidence of validity and potential for sensitivity to change. In an effort to support the construct validity of the new scales, they were compared with the Child Health Questionnaire and related to each other in clinically sensible ways. These burn outcomes scales reliably and validly assess function in patients with burns, and the scales have been developed in such a way that they are likely to be sensitive to change over time.

Disparity in Total Hip Replacement Affecting Hispanic Medicare Beneficiaries

Objective. To compare the utilization of total hip replacement (THR) between Hispanic persons and non-Hispanic persons in a sample with health insurance. Research Design. Case-control study using Medicare claims data. Patients. The cases were Medicare beneficiaries from Arizona, Illinois, New Mexico, or Texas who underwent a primary THR. The controls were Medicare beneficiaries who did not receive a THR, matched by age, sex, and county of residence. Measures. Beneficiary surnames and the race indicator in Medicare records were used to classify beneficiaries’ probability of being Hispanic. Conditional logistic regression was used to estimate the odds of receiving of THR, adjusting for Medicaid eligibility. Results. Six thousand four hundred thirty-seven recipients of a primary THR were matched to 12,874 controls. According to the Medicare race indicator, 1% of recipients of THR and 3.3% of controls were Hispanic (P ≤0.001). The odds of THR decreased as the probability of Hispanic ethnicity increased, from an odds ratio (OR) of 1.00 among beneficiaries with non-Hispanic surnames, to an OR of 0.36 among those with heavily Hispanic surnames (95% CI, 0.31, 0.43). Poverty, as reflected by eligibility for Medicaid, did not modify the low odds of THR among Hispanic persons (OR, 0.25 among Medicaid-eligible Hispanic persons; 95% CI, 0.19, 0.33; and OR, 0.30 among Hispanic persons not Medicaid eligible; 95% CI, 0.24, 0.38). Conclusion. Hispanic persons with Medicare receive THR at lower rates than do non-Hispanic persons. Because Medicare covers THR, our findings suggest that under utilization of THR by Hispanic persons cannot be attributed to lack of health insurance alone.

The development, validation, and testing of a health outcomes burn questionnaire for infants and children 5 years of age and younger: American Burn Association/Shriners Hospitals for Children.

The 12-member American Burn Association/Shriners Hospitals for Children Outcomes Task Force was charged with developing a health outcomes questionnaire for use in children 5 years of age and younger that was clinically based and valid. A 55-item form was tested using a cross-sectional design on the basis of a range of 184 infants and children between 0 and 5 years of age at 8 burn centers, nationally. A total of 131 subjects completed a follow-up health outcomes questionnaire 6 months after the baseline assessment. A comparison group of 285 normal nonburn children was also obtained. Internal consistency reliability of the scales ranged from 0.74 to 0.94. Tests of clinical validity were significant in the hypothesized direction for the majority of scales for length of hospital stay, duration since the burn, percent of body surface area burned, overall clinician assessment of severity of burn injury, and number of comorbidities. The criterion validity of the instrument was supported using the Child Developmental Inventories for Burn Children in early childhood and preschool stages of development comparing normal vs abnormal children. The instrument was sensitive to changes over time following a clinical course observed by physicians in practice. The Health Outcomes Burn Questionnaire for Infants and Children 5 years of age and younger is a clinically based reliable and valid assessment tool that is sensitive to change over time for assessing burn outcomes in this age group.

The validity and reliability of a Total Hip Arthroplasty Outcome Evaluation Questionnaire.

The Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT), the Task Force on Outcome Studies of The American Academy of Orthopaedic Surgeons, and The Hip Society reached a consensus on the nomenclature to be used for the evaluation of the results of total hip arthroplasty. The Task Force of The American Academy of Orthopaedic Surgeons, to assess the results of total hip arthroplasty from the perspective of the patient, subsequently developed a questionnaire that incorporated this nomenclature. The validity and reliability data regarding this questionnaire are reported in this study. Twenty-five patients participated in the reliability test. The non-response rate was five (0.5 per cent) of 941 possible responses. Test-retest reliability was determined by calculating the Spearman correlation coefficients for each question. The coefficients ranged from 0.41 to 1.0 over a mean test-retest interval of sixteen days. Most items had Spearman coefficients that were greater than 0.50, indicating good or excellent reliability. Validity was assessed, for the fifty-four patients who participated, by calculating the Spearman correlation coefficients for the items regarding pain in the affected hip, limitation of usual activities, capacity for walking without support, and the Sickness Impact Profile. The coefficients ranged from 0.11 (pain and limitation of activity) to 0.56 (Sickness Impact Profile and limitation of activity). These coefficients reflected modest associations, as anticipated, indicating that pain, function, and health status are related yet distinct concepts.(ABSTRACT TRUNCATED AT 250 WORDS)