Nizar N. Mahomed

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.

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.

Association Between Hospital and Surgeon Procedure Volume and the Outcomes of Total Knee Replacement

BACKGROUND The annual volume of major cardiovascular and oncologic procedures performed in hospitals and by surgeons has been inversely associated with the rates of perioperative mortality and complications. The relationship between hospital and surgeon volume and perioperative outcomes following total knee replacement has received little study. METHODS We analyzed claims data for Medicare patients who had elective primary total knee replacement between January 1 and August 31, 2000. Hospital and surgeon volumes were defined as the number of primary and revision total knee replacements performed in the hospital or by the surgeon in Medicare recipients in 2000. We examined the associations between the annual volumes of total knee replacement performed in the hospitals and by the surgeons and the rates of mortality and complications (infection, pulmonary embolus, myocardial infarction, or pneumonia) in the first ninety days postoperatively. The analyses were adjusted for age, gender, comorbid conditions, Medicaid eligibility (a marker of low income), and arthritis diagnosis. Analyses of hospital volume were adjusted for surgeon volume and vice versa. RESULTS Twenty-five percent of the primary total knee replacements were done by surgeons who performed twelve of these procedures or fewer in the Medicare population annually, and 11% were done in hospitals with an annual volume of twenty-five of these procedures or fewer. Compared with the patients who had a primary total knee replacement in hospitals with an annual volume of twenty-five procedures or fewer, those managed in hospitals with an annual volume exceeding 200 procedures had a lower risk of pneumonia (odds ratio, 0.65; 99% confidence interval, 0.47 to 0.90) and any of the adverse outcomes examined (death, pneumonia, pulmonary embolus, acute myocardial infarction, or deep infection) (odds ratio, 0.74; 99% confidence interval, 0.60 to 0.90). Similarly, patients who had a primary total knee replacement done by surgeons who performed more than fifty such procedures in Medicare recipients annually had a lower risk of pneumonia (odds ratio, 0.72; 99% confidence interval, 0.54 to 0.95) and any adverse outcome (odds ratio, 0.81; 99% confidence interval, 0.68 to 0.98) compared with patients of surgeons with an annual volume of twelve procedures or fewer. CONCLUSIONS Patients managed at hospitals and by surgeons with greater volumes of total knee replacement have lower risks of perioperative adverse events following primary total knee replacement. Patients and clinicians should incorporate these findings into discussions about selecting a surgeon and a hospital for total knee replacement. These data should also be integrated into the policy debate about the advantages and drawbacks of regionalizing total joint replacement to high-volume centers.

Epidemiology of Total Knee Replacement in the United States Medicare Population

BACKGROUND There are limited population-based data on the utilization and outcomes of total knee replacement. The aim of the present study was to describe the rates of primary and revision total knee replacement and selected outcomes in persons older than sixty-five years of age in the United States. METHODS Using Medicare claims, we computed annual incidence rates of unilateral elective primary and revision total knee replacement among United States Medicare beneficiaries in the year 2000. Poisson regression was used to assess the relationships between demographic characteristics and the incidence rates of primary and revision knee replacement. Proportional hazards models were used to examine the relationships between the ninety-day rates of complications and demographic and clinical factors. RESULTS The rate of primary knee replacement was lower in blacks than in whites and in those qualifying for Medicaid supplementation than in those with higher incomes. The complications observed during the ninety days following primary knee replacement included mortality (0.7%), readmission (0.9%), pulmonary embolus (0.8%), wound infection (0.4%), pneumonia (1.4%), and myocardial infarction (0.8%). The complications observed during the ninety days following revision knee replacement were mortality (1.1%), readmission (4.7%), pulmonary embolus (0.5%), wound infection (1.8%), pneumonia (1.4%), and myocardial infarction (1.0%). Blacks had higher rates of mortality, readmission, and wound infection after primary knee replacement than whites did. Patients who qualified for Medicaid supplementation had higher complication rates, particularly after primary knee replacement. CONCLUSIONS Overall, the rates of postoperative complications during the ninety days following total knee replacement are low. In the United States, blacks and individuals with low income undergo total knee replacement less frequently and generally have higher rates of adverse outcomes following primary knee replacement.

Topical Application of Tranexamic Acid Reduces Postoperative Blood Loss in Total Knee Arthroplasty: A Randomized, Controlled Trial

BACKGROUND Topical application of tranexamic acid to bleeding wound surfaces reduces blood loss in patients undergoing some major surgeries, without systemic complications. The objective of the present trial was to assess the efficacy and safety of the topical application of tranexamic acid on postoperative blood loss in patients undergoing primary unilateral total knee arthroplasty with cement. METHODS In a prospective, double-blind, placebo-controlled trial, 124 patients were randomized to receive 1.5 or 3.0 g of tranexamic acid in 100 mL of normal saline solution or an equivalent volume of placebo (normal saline solution) applied into the joint for five minutes at the end of surgery. The primary outcome was blood loss calculated from the difference between the preoperative hemoglobin level and the corresponding lowest postoperative value or hemoglobin level prior to transfusion. The safety outcomes included Doppler ultrasound in all patients and measurement of plasma levels of tranexamic acid one hour after release of the tourniquet. RESULTS Twenty-five patients were withdrawn for various reasons; therefore, ninety-nine patients were included in the intention-to-treat analysis. The postoperative blood loss was reduced in the 1.5 and 3-g tranexamic acid groups (1295 mL [95% confidence interval, 1167 to 1422 mL] and 1208 mL [95% confidence interval, 1078 to 1339 mL], respectively) in comparison with the placebo group (1610 mL [95% confidence interval, 1480 to 1738 mL]) (p < 0.017). The postoperative hemoglobin levels were higher in the 1.5 and 3.0-g tranexamic acid groups (10.0 g/dL [95% confidence interval, 9.5 to 10.4 g/dL] and 10.1 g/dL [95% confidence interval, 9.8 to 10.5 g/dL], respectively) in comparison with the placebo group (8.6 g/dL [95% confidence interval, 8.2 to 9 g/dL]) (p < 0.017). With the numbers studied, there was no difference in the rates of deep-vein thrombosis or pulmonary embolism between the three groups. Minimal systemic absorption of tranexamic acid was observed. CONCLUSIONS At the conclusion of a total knee arthroplasty with cement, topical application of tranexamic acid directly into the surgical wound reduced postoperative bleeding by 20% to 25%, or 300 to 400 mL, resulting in 16% to 17% higher postoperative hemoglobin levels compared with placebo, with no clinically important increase in complications being identified in the treatment groups.

Inpatient compared with home-based rehabilitation following primary unilateral total hip or knee replacement: a randomized controlled trial.

BACKGROUND Home-based rehabilitation is increasingly utilized to reduce health-care costs; however, with a shorter hospital stay, the possibility arises for an increase in adverse clinical outcomes. We evaluated the effectiveness and cost of care of home-based compared with inpatient rehabilitation following primary total hip or knee joint replacement. METHODS We randomized 234 patients, using block randomization techniques, to either home-based or inpatient rehabilitation following total joint replacement. All patients followed standardized care pathways and were evaluated, with use of validated outcome measures (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Short Form-36, and patient satisfaction), prior to surgery and at three and twelve months following surgery. The primary outcome was the WOMAC function score at three months after surgery. RESULTS The mean length of stay (and standard deviation) in the acute care hospital was 6.3 +/- 2.5 days for the group designated for inpatient rehabilitation prior to transfer to that facility compared with 7.0 +/- 3.0 days for the home-based rehabilitation group prior to discharge home (p = 0.06). The mean length of stay in inpatient rehabilitation was 17.7 +/- 8.6 days. The mean number of postoperative home-based rehabilitation visits was eight. The prevalence of postoperative complications up to twelve months postoperatively was similar in both groups, which each had a 2% rate of dislocation and a 3% rate of clinically important deep venous thrombosis. The prevalence of infection was 0% in the home-based group and 2% in the inpatient group. None of these differences was clinically important. Both groups showed substantial improvements at three and twelve months, with no significant differences between the groups with respect to WOMAC, Short Form-36, or patient satisfaction scores (p > 0.05). The total episode-of-care costs (in Canadian dollars) for the inpatient rehabilitation and home-based rehabilitation arms were

Patient Expectations Predict Greater Pain Relief with Joint Arthroplasty

14,532 and

Comparison of Early and Delayed Fixation of Subcapital Hip Fractures in Patients Sixty Years of Age or Less

11,082, respectively (p < 0.01). CONCLUSIONS Despite concerns about early hospital discharge, there was no difference in pain, functional outcomes, or patient satisfaction between the group that received home-based rehabilitation and the group that had inpatient rehabilitation. On the basis of our findings, we recommend the use of a home-based rehabilitation protocol following elective primary total hip or knee replacement as it is the more cost-effective strategy.

Biomechanical analysis of the gamma nail and sliding hip screw

We examined the relationship between patient expectations of total joint arthroplasty and functional outcomes. We surveyed 1799 patients undergoing primary hip or knee arthroplasty for demographic data and Western Ontario McMaster University Osteoarthritis Index scores at baseline, 3 months, and 1 year of follow-up. Patient expectations were determined with 3 survey questions. The patients with the greatest expectations of surgery were younger, male, and had a lower body mass index. Linear regression modeling showed that a greater expectation of pain relief with surgery independently predicted greater reported pain relief at 1 year of follow-up, adjusted for all relevant covariates (P < .05). Patient expectation of pain relief after joint arthroplasty is an important predictor of outcomes at 1 year.