Fahad Razak

Predicting the longer term outcomes of total knee arthroplasty

We asked the question of what are the patient level predictors (age, gender, body mass index, education, ethnicity, mental health, and comorbidity) for a sustained functional benefit at a minimum of 1 year follow-up after total knee arthroplasty(TKA). Five hundred fifty-one consecutive patients were reviewed from our joint registry between the years of 1998 and 2005. Baseline demographic data and the outcome scores of the Western Ontario McMaster University Osteoarthritis Index (WOMAC) and Medical Outcomes Short-Form 36 (SF36) scores were extracted from the database. Longitudinal regression modeling was performed to identify the predictive factors of interest. We had 27% of data points missing. The mean follow-up in our cohort was 3.0 years (range 1-8 years) and there were no revisions performed during this time. Clinical outcome scores were found to be relatively constant for 3-4 years after surgery and then demonstrated a gradual decline after that. Older age, year of follow-up, greater comorbidity, and a poorer mental health state at time of surgery were identified as negative prognostic factors for a sustained functional outcome following TKR (P<0.05). Knowledge of these factors that predict outcomes should be used in setting appropriate patient expectations of surgery.

Metabolic Syndrome and the Functional Outcomes of Hip and Knee Arthroplasty

Objective. Patients with an elevated systemic inflammatory state are known to report greater pain with knee osteoarthritis (OA). We investigated the influence of risk factors of metabolic syndrome (MetS) on patient function before and after hip and knee replacement surgery. Methods. A total of 677 consecutive patients with primary knee replacement and 547 consecutive patients with primary hip replacement with at least one MetS risk factor were reviewed from our joint registry. Demographic variables of age, sex, and comorbidity were retrieved. MetS risk factors were defined as body mass index (BMI) > 30 kg/m2, diabetes, hypertension, and hypercholesterolemia. Baseline and 1-year Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores were compared across patients by number of MetS risk factors, ranging from 1 to 4. Linear regression modeling was used to evaluate the effects of the MetS risk groups and the individual metabolic abnormalities on predicting baseline and 1-year WOMAC scores. Knee and hip patients were reviewed separately. Results. The knee and hip patients showed a significant difference in sex distribution, BMI, and mean comorbidity across risk groups (p < 0.05). Unadjusted analysis showed that baseline and 1-year WOMAC scores, for both knee and hip patients, increased significantly with increasing number of MetS risk factors (p < 0.05). The linear regression model with the individual metabolic abnormalities was found to be more predictive of outcome than one with the number of MetS risk factors. Hypertension and obesity were the metabolic factors most predictive of a poorer outcome following hip surgery as compared to just obesity for knee patients. Conclusion. Patient function following joint replacement surgery, particularly hip surgery, is negatively affected by metabolic abnormalities perhaps secondary to the systemic proinflammatory state. This knowledge should be used when counseling patients prior to surgery.

Change in the Body Mass Index Distribution for Women: Analysis of Surveys from 37 Low- and Middle-Income Countries

Using cross-sectional surveys, Fahad Razak and colleagues investigate how the BMI (body mass index) distribution is changing for women in low- and middle-income countries.

BMI Independently Predicts Younger Age at Hip and Knee Replacement

Obesity has been identified as a risk factor for the development of hip and knee osteoarthritis (OA) and may play a role in exacerbating existing disease. Therefore, we hypothesized that obese patients would present for hip and knee replacement surgery at a younger age than nonobese patients. From our registry, we performed a cross‐sectional study of 841 hip and 804 knee replacement patients. Patients were categorized by BMI ≤25 kg/m2, 25.1–29.9 kg/m2, 30–34.9 kg/m2, and ≥35 kg/m2. Linear regression modeling was used to examine the relationship between BMI and age at surgery. Hip and knee replacement patients mean age at surgery was 7.1 and 7.9 years younger, respectively, if their BMI was ≥35 kg/m2 when compared to patients with a BMI ≤25 kg/m2 (P = 0.002). BMI was a significant independent (of gender, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, surgeon, and comorbidity) predictor of age at knee replacement (P < 0.05). WOMAC scores were significantly worse preoperatively in patients with a BMI ≥35 kg/m2 compared to those with a BMI ≤25 kg/m2 (P < 0.05). Our study indicates that obese patients, especially those with a BMI ≥35 kg/m2, presented for and underwent joint replacement surgery at a younger age as compared to nonobese patients.

Antibiotic bone cement and the incidence of deep infection after total knee arthroplasty.

We asked if the use of antibiotic-laden bone cement (ALBC) decreased the deep infection rate after primary total knee arthroplasty as compared to plain bone cement. We surveyed 1625 consecutive patients for relevant covariates. Joint pain and function were assessed at baseline and at 1 year of follow-up with the Western Ontario McMaster University Osteoarthritis Index scores. The incidence of deep infection at 1-year follow-up was recorded. There were no differences in baseline covariates between groups (P > .05). We found a deep infection rate of 2.2% in the ALBC group and 3.1% in the plain bone cement group (P = .27). Adjusted analysis showed that ALBC was not predictive of a lower infection rate at 1 year (P = .84). Antibiotic-laden bone cement did not reduce the incidence of deep infection following primary total knee arthroplasty at 1-year follow-up.

Metabolic Syndrome and the Incidence of Symptomatic Deep Vein Thrombosis Following Total Knee Arthroplasty

Objective. We asked if patients with metabolic syndrome undergoing total knee replacement (TKR) have an increased risk for symptomatic deep vein thrombosis (DVT) at 3 months followup. Methods. We reviewed 1460 patients from our joint registry undergoing primary, unilateral TKR between 1998–2006. Demographic variables of age, sex, comorbidity, and education were retrieved. Metabolic syndrome was defined as body mass index above 30 kg/m2, diabetes, hypertension, and hypercholesterolemia. Logistic regression was used to examine the relationship of metabolic syndrome on the incidence of DVT. Results. The overall incidence of symptomatic DVT was 4.4% (65/1460). Patients with metabolic syndrome had an increased incidence of DVT compared to those without metabolic syndrome (15.5% vs 3.4%). Adjusted analysis showed that the risk of symptomatic DVT in patients with metabolic syndrome was 3.2 times [odds ratio 3.2, 95% CI (1.0,15.4), p = 0.04] the risk in those without metabolic syndrome. Conclusion. Hospital protocols developed for prophylactic anticoagulation following TKR should give special consideration to patients with metabolic syndrome.

Greater Perceived Helplessness in Osteoarthritis Predicts Outcome of Joint Replacement Surgery

Objective. To determine if there is a difference between male and female patients in their perceived control of osteoarthritis (OA) symptoms at the time of joint replacement surgery, as measured by the Arthritis Helplessness Index (AHI), and how this helplessness affects surgical outcomes at 1 year. Methods. From a joint replacement registry, 70 male and 70 female patients were randomly selected and matched for age, body mass index, comorbidity, procedure, and education. Patients completed the AHI prior to surgery. Functional status was assessed at baseline and 1-year followup with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Linear regression modeling was used to determine the effect of sex on predicting AHI scores. A second model was constructed to examine the effect of AHI on the 1-year WOMAC change score. Results. There were no statistically significant differences in demographic data or clinically significant differences in AHI scores between sexes. Linear regression modeling showed that female sex was a significant predictor of a greater AHI score prior to surgery (p < 0.05). Moreover, a greater AHI score was an independent predictor of a lower WOMAC change score at 1 year (p = 0.01). Conclusion. Interventions to improve control over arthritis symptoms should be studied with the goal of improving surgical outcomes.

Distributional change of women’s adult height in low- and middle-income countries over the past half century: An observational study using cross-sectional survey data

[This corrects the article DOI: 10.1371/journal.pmed.1002568.].