Hassan M.K. Ghomrawi

Current etiologies and modes of failure in total knee arthroplasty revision.

Although total knee arthroplasty is a very effective intervention and increasing in prevalence, failures do occur. We studied patients presenting for total knee arthroplasty revision to determine any modifiable causes of failure, both short and long term, and where future efforts should be directed to reduce the incidence of failure. A multicenter prospective observational cohort study of 318 consecutive patients, with minimum 1 year follow-up, undergoing total knee arthroplasty revision was performed. Associations between modes of failure were also assessed. The mean time from primary procedure to total knee arthroplasty revision was 7.9 years. Many patients (64.4%) had more than one cause of failure. Thirty-one percent of patients were early (< 2 years) failures at a mean of 11 months. These had a higher prevalence of infection, perioperative factors and comorbidities. Late failures occurred at a mean of 119.2 months. Other major causes of failure included instability (28.9%), wear (24.5%) and component loosening suggesting the importance of modifications in technique, implants and other areas. Application of these findings will ultimately reduce revision numbers through continued refinement of total knee arthroplasty practice and through further specific investigation of these modes of failure.Level of Evidence: Therapeutic study, level II-2 (prospective study). See the Guidelines for Authors for a complete description of levels of evidence.

The Impact of Valve Surgery on 6-Month Mortality in Left-Sided Infective Endocarditis

Background— The role of valve surgery in left-sided infective endocarditis has not been evaluated in randomized controlled trials. We examined the association between valve surgery and all-cause 6-month mortality among patients with left-sided infective endocarditis. Methods and Results— A total of 546 consecutive patients with left-sided infective endocarditis were included. To minimize selection bias, propensity score to undergo valve surgery was used to match patients in the surgical and nonsurgical groups. To adjust for survivor bias, we matched the follow-up time so that each patient in the nonsurgical group survived at least as long as the time to surgery in the respective surgically-treated patient. We also used valve surgery as a time-dependent covariate in different Cox models. A total of 129 (23.6%) patients underwent surgery within 30 days of diagnosis. Death occurred in 99 of the 417 patients (23.7%) in the nonsurgical group versus 35 deaths among the 129 patients (27.1%) in the surgical group. Eighteen of 35 (51%) patients in the surgical group died within 7 days of valve surgery. In the subset of 186 cases (93 pairs of surgical versus nonsurgical cases) matched on the logit of their propensity score, diagnosis decade, and follow-up time, no significant association existed between surgery and mortality (adjusted hazard ratio, 1.3; 95% confidence interval, 0.5 to 3.1). With a Cox model that incorporated surgery as a time-dependent covariate, valve surgery was associated with an increase in the 6-month mortality with an adjusted hazard ratio of 1.9 (95% confidence interval, 1.1 to 3.2). Because the proportionality hazard assumption was violated in the time-dependent analysis, we performed a partitioning analysis. After adjustment for early (operative) mortality, surgery was not associated with a survival benefit (adjusted hazard ratio, 0.92; 95% confidence interval, 0.48 to 1.76). Conclusions— The results of our study suggest that valve surgery in left-sided infective endocarditis is not associated with a survival benefit and could be associated with increased 6-month mortality, even after adjustment for selection and survivor biases as well as confounders. Given the disparity between the results of our study and those of other observational studies, well-designed prospective studies are needed to further evaluate the role of valve surgery in endocarditis management.

Appropriateness Criteria and Elective Procedures — Total Joint Arthroplasty

The implementation of appropriateness criteria that help to identify the patients likely to benefit most from a given procedure could help to combat increasing health care costs while enhancing access and quality. Total joint arthroplasty offers a prime example.

How Often are Patient and Surgeon Recovery Expectations for Total Joint Arthroplasty Aligned? Results of a Pilot Study

BackgroundSurgeons strive to set patient expectations for recovery following total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, some patients report dissatisfaction after surgery due to unmet expectations.PurposeWe compared patients’ and surgeon’s recovery expectations prior to primary THA and TKA.MethodsSixty eight patients scheduled to undergo primary total hip replacement (THR) or total knee replacement (TKR) surgery were enrolled. Before surgery, patients filled out a validated recovery expectations questionnaire that quantified expectations of postoperative pain relief, function, and well-being with a value from 0 to 100 (higher being more optimistic). The surgeon independently completed the same questionnaire for each patient. Overall score and item-specific comparisons were conducted. Correlations were explored between agreement level, demographics, patient-reported health status measures, and patients’ assessments of the risk of complications associated with surgery.ResultsMost patients undergoing THR or TKR had higher expectations for recovery than their surgeon. Applying the clinically meaningful difference in expectations (≥7 points), 52.5% of the TKA patients’ expectations exceeded those of the surgeon, while 22.5% expected less than their surgeon and 60.7% of THA patients’ expectations exceeded those of the surgeon, while 21.4% expected less than their surgeon. THA patients with either lower or higher expectations than their surgeon had lower physical and mental health status scores. TKA patients with lower expectations compared to their surgeon had a higher expectation of complications.ConclusionsMore than 50% of the patients had higher expectations than their surgeon and this was driven by expectations of high-level activities and extreme range of motion. Further investigations are needed to understand these differences so as to enhance patient preoperative education.

The association between the timing of valve surgery and 6-month mortality in left-sided infective endocarditis

Objective: The optimal timing of valve surgery in left-sided infective endocarditis (IE) is undefined. We aimed to examine the association between the timing of valve surgery after IE diagnosis and 6-month mortality among patients with left-sided IE. Methods: We analysed data from a retrospective cohort of patients with left-sided IE who underwent valve surgery within 30 days of diagnosis at a tertiary centre. The association between time from IE diagnosis to surgery and all-cause 6-month mortality was assessed using Cox proportional hazards modelling after adjusting for the propensity score (to undergo surgery 0–11 days vs >11 days, median time, after IE diagnosis). Results: Of 546 left-sided IE cases seen between 1980 and 1998, 129 (23.6%) underwent valve surgery within 30 days of diagnosis. The median time between IE diagnosis and surgery was 11 days (range 1–30). There were 35/129 (27.2%) deaths in the surgical group. Using Cox proportional hazards modelling, propensity score and longer time to surgery (in days) were associated with unadjusted HRs of (1.15, 95% CI 1.04 to 1.28, per 0.10 unit change, p = 0.009) and (0.93; 95% CI 0.88 to 0.99, per day, p = 0.03), respectively. In multivariate analysis, a longer time to surgery was associated with an adjusted HR (0.97; 95% CI 0.90 to 1.03). The propensity score and time from diagnosis to surgery had a correlation coefficient of r = −0.63, making multicollinearity an issue in the multivariable model. Conclusion: On univariate analysis, a longer time to surgery showed a significant protective effect for the outcome of mortality. After adjusting for the propensity to undergo surgery early versus late, a longer time to surgery was no longer significant but remained in the protective direction. Multicollinearity between the time to surgery and the propensity score may have hindered our ability to detect the independent effect of time to surgery.

Socioeconomic issues and demographics of total knee arthroplasty revision

Despite rising numbers of total knee arthroplasty revision (TKAR) procedures there remains a paucity of information regarding the relationships between total knee arthroplasty failure and socioeconomic and educational status, demographics, general health and functional disability. We performed a multicenter prospective study of 290 consecutive TKAR patients in order to determine whether they differed from the population they were drawn from in terms of socioeconomic or educational status, race or gender. Secondary aims were to establish the relative comorbid status of this population, social supports and their general health status compared to national norms and their modes of failure. Our cohort consisted of 137 males and 153 females with a mean age of 68.6 years (range, 34-85 years), substantial overall functional disability according to the SF-36 and a large average number of comorbidities at baseline. We found a relative overrepresentation of patients of comparatively low socioeconomic and educational status and also of Caucasian patients in the TKAR population. This large prospective investigation demonstrates demographic features associated with TKA failure and provides a platform for further investigations on the effect demographic characteristics have on the outcomes of TKAR.Level of Evidence: Prognostic Study, Level II (Lesser quality prospective study). See Guidelines for Authors for a complete description of the Levels of Evidence.

Radiographic prediction of intraoperative bone loss in knee arthroplasty revision.

A key challenge for orthopaedic surgeons performing revision total knee arthroplasty is the management of bone loss. The goal of our study was to test the validity of predicting bone loss from preoperative radiographs using two commonly utilized bone loss assessments: the Anderson Orthopaedic Research Institute and University of Pennsylvania systems and secondarily to assess the frequency and severity of bone loss in a prospective study of total knee arthroplasty revisions. Ninety-eight total knee arthroplasty revision patients were assessed and bone loss was detected in 76 (77.6%) patients preoperatively and intraoperatively. The validity of both systems was established. Agreement between preoperative and intraoperative Anderson Orthopaedic Research Institute classification was fair for the femur and good for the tibia. All University of Pennsylvania preoperative measures were correlated with intraoperative measures. Establishing valid and reliable preoperative systems of measuring bone loss facilitates planning of total knee arthroplasty revision and rehabilitation and meaningful comparisons between different series of patients and treatment protocols.Level of Evidence: Diagnostic study, level I (prospective testing of previously developed diagnostic criteria on consecutive patients [with universally applied reference “gold” standard]). See Author Guidelines for a complete description of levels of evidence.

Patterns of functional improvement after revision knee arthroplasty

BACKGROUND Despite the increase in the number of total knee arthroplasty revisions, outcomes of such surgery and their correlates are poorly understood. The aim of this study was to characterize patterns of functional improvement after revision total knee arthroplasty over a two-year period and to investigate factors that affect such improvement patterns. METHODS Three hundred and eight patients in need of revision surgery were enrolled into the study, conducted at seventeen centers, and 221 (71.8%) were followed for two years. Short Form-36 (SF-36), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lower-Extremity Activity Scale (LEAS) scores were collected at baseline and every six months for two years postoperatively. A piecewise general linear mixed model, which models correlation between repeated measures and estimates separate slopes for different follow-up time periods, was employed to examine functional improvement patterns. RESULTS Separate regression slopes were estimated for the zero to twelve-month and the twelve to twenty-four-month periods. The slopes for zero to twelve months showed significant improvement in all measures in the first year. The slopes for twelve to twenty-four months showed deterioration in the scores of the WOMAC pain subscale (slope = 0.67 +/- 0.21, p < 0.01) and function subscale (slope = 1.66 +/- 0.63, p < 0.05), whereas the slopes of the other measures had plateaued. A higher number of comorbidities was consistently the strongest deterrent of functional improvement across measures. The modes of failure of the primary total knee arthroplasty were instrument-specific predictors of outcome (for example, tibial bone lysis affected only the SF-36 physical component score [coefficient = -5.46 +/- 1.91, p < 0.01], while malalignment affected both the SF-36 physical component score [coefficient = 5.41 +/- 2.35, p < 0.05] and the LEAS score [coefficient = 1.42 +/- 0.69, p < 0.05]). Factors related to the surgical technique did not predict outcomes. CONCLUSIONS The onset of worsening pain and knee-specific function in the second year following revision total knee arthroplasty indicates the need to closely monitor patients, irrespective of the mode of failure of the primary procedure or the surgical technique for the revision. This information may be especially important for patients with multiple comorbidities.

The providers of health services in Lebanon: a survey of physicians

BackgroundEmerging from civil distress carries with it major challenges to reforming a health system. One such challenge is to ensure an adequate supply of competent human resources. The objective of this study was to assess the supply of physicians in Lebanon in 1998, with an assessment of their practice patterns and capacity building.MethodsLists of members of physicians associations were examined to determine the number of physicians in Lebanon and their geographical distribution. A self-administered survey targeted 388 physicians (5%) randomly stratified by the five regions of Lebanon. Some 377 providers reported information on their demographic profile, practice patterns and development. Further, information on continuing education activities was acquired.ResultsIn Lebanon, the overall physician-to-population ratio was 248 per 100, 000, characterized by an evident maldistribution at the intracountry regional level. Physicians worked 38 hours per week examining on average 21 patients per day, with an average time of 30 minutes spent per visit. They also reported spending 11% of their time waiting for patients. Respondents reported a very wide range of income, with 90% earning less than USD 2,000 per month. Moreover, the continuing education profile revealed a total of 43.7 hours per year, similar to that required for board certification in many developed countries. Conference attendance was the dominant continuing education activity (95% of respondents) and consumed most of the time allotted for continuing education, reported at 32 hours per year.Discussion and conclusionVarious economic indicators point to an oversupply of physicians in Lebanon and a poor allocation of their time for capacity building. Therefore, it is crucial for decision-makers to closely monitor the increasing supply of providers and institute appropriate intervention strategies, taking into consideration appropriate provision of good-quality services and ensuring that continuing education activities are well established, organized and monitored.

Conclusion about the association between valve surgery and mortality in an infective endocarditis cohort changed after adjusting for survivor bias

OBJECTIVE Survivor bias commonly weakens observational studies, even those published in premier journals. It occurs because patients who live longer are more likely to receive treatment than those who die early. We sought to quantify the effect of survivor bias on the association between valve surgery and mortality in infective endocarditis (IE). STUDY DESIGN AND SETTING The study cohort included 546 IE patients. We compared the hazard ratios (HR) resulting from two propensity score analysis approaches that adjusted for survivor bias (time-dependent variable and matching on follow-up time) with those achieved using the same models but without that adjustment (time-fixed variable). RESULTS In the total cohort, the HR of surgery in the time-dependent model was 1.9 (95% confidence interval [CI] = 1.1-3.2; P = 0.03) vs. 0.9 (95% CI = 0.5-1.4; P = 0.53) in the time-fixed model. In the propensity score-matched subset, the HR of surgery was 1.3 (95% CI = 0.5-3.1; P = 0.56) and 0.8 (95% CI = 0.4-1.7; P = 0.57) in the subset with and without matching on follow-up time, respectively. CONCLUSION Adjusting for survivor bias changed the conclusion about the association between valve surgery and mortality in IE. Researchers should be aware of this bias when evaluating observational studies of treatment efficacy.