Abiram Bala

Outcomes after Total Knee Arthroplasty for post-traumatic arthritis.

INTRODUCTION Total Knee Arthroplasty (TKA) is an important treatment for posttraumatic arthritis (PTA), but evidence on outcomes is sparse. The purpose of this study was to evaluate the impact of PTA versus primary osteoarthritis (OA) on postoperative outcomes after TKA. METHODS We queried the entire Medicare database from 2005 to 2012. International Classification of Diseases, 9th revision and Current Procedural Terminology codes were used to identify the procedure, indication, and complications. Patients with minimum two-years follow-up were selected. Odds ratios (ORs), confidence intervals, and p-values (p) were calculated. RESULTS For PTA, 3509 patients had TKA. For OA, 257,611 patients with TKA served as controls. The average Charlson Comorbidity Index for both groups was five. PTA patients were younger; only eight out of 29 Elixhauser comorbidities were higher. PTA patients had higher incidence of periprosthetic infection (OR 1.72, p<0.001), cellulitis or seroma (OR 1.19, p<0.001), knee wound complications (OR 1.80, p<0.001), TKA revision (OR 1.23, p=0.01), and arthrotomy/incision and drainage (OR 1.55, p<0.001). Blood transfusion rate was lower in PTA patients. There were no significant differences in bleeding complications, prosthetic dislocation, broken prostheses, periprosthetic fracture, osteolysis and polywear, neurovascular injury, and extensor mechanism rupture. DISCUSSION AND CONCLUSION This study represents, to our knowledge, TKA outcomes in the largest cohort of PTA patients to date. Our findings indicate that these patients are at higher risk for many, but not all, postoperative surgical complications despite being as healthy as patients receiving TKA for primary OA.

Psychiatric disorders increase complication rate after primary total knee arthroplasty

BACKGROUND Psychiatric disease is difficult to screen preoperatively and the incidence of mental health disorders in patients undergoing total knee arthroplasty (TKA) may be underappreciated. The purpose of this study is to evaluate the perioperative complication profile in patients with psychiatric disorders. METHODS A search of the entire Medicare database from 2005 to 2011 was performed to identify patients who underwent primary TKA with bipolar disorder (20,972), depression (187,448), and schizophrenia (7607). A cohort of 1,271,464 patients as controls with minimum 2.5-year follow-up. Medial and surgical complications at 30-days, 90-days, and overall were compared between the two cohorts. RESULTS Patients with any psychiatric disease were more likely to be younger (age<65 OR 5.5, p<0.001), female (OR 2.61, p<0.001), and more medically complex (significant increase in 28/28 Elixhauser medical comorbidities, p<0.05). There was a significant increase (p<0.001) in 11/14 (78.5%) of recorded postoperative medical complication rates at 90-days. There was a statistically significant increase in periprosthetic infection (OR 2.17 p<0.001), periprosthetic fracture (OR 2.40, p<0.001), revision TKA (OR 2.06, p<0.001), and extensor mechanism rupture (OR 2.41, p<0.001) at 90day and overall time points. CONCLUSIONS Patients with psychiatric disorders who undergo elective primary TKA have significantly increased medical and surgical complication rates in the global period and short term follow-up. An ideal screening tool is yet to be determined and these patients need to be counseled appropriately regarding the increased complication rates before proceeding with TKA.

How Do Previous Solid Organ Transplant Recipients Fare After Primary Total Knee Arthroplasty

INTRODUCTION Total knee arthroplasty (TKA) has been proven to increase knee outcome scores after solid organ transplantation (SOT), but many authors are concerned about a higher complication rate. The purpose of this study is to evaluate the complication profile of TKA after previous SOT. METHODS A search of the entire Medicare database from 2005 to 2011 was performed using International Classification of Disease, version 9, codes to identify 3339 patients who underwent TKA after 1 or more solid organ transplants including the kidney (2321), liver (772), lung (129), heart (412), and pancreas (167). A cohort of 1,685,295 patients served as a control with minimum 2-year follow-up. Postoperative complications at 30-day, 90-day, and overall time points were compared between the 2 cohorts. RESULTS Patients with any SOT were younger (age: <65, odds ratio [OR]: 6.58, P < .001), male (OR: 1.88, P < .001), and medically complex (significant increase in 28 of 29 Elixhauser comorbidities, P < .05). There was a significant increase (P < .05) in 11 of 13 (84.6%) recorded postoperative medical complications rates at 90 days. There was a significant increase overall in periprosthetic infection (OR: 2.11, P < .001), periprosthetic fracture (OR: 1.78, P < .001), and TKA revision (OR: 1.36, P < .001). When analyzed by individual organ, heart and lung transplants carried the fewest medical and surgical complications. CONCLUSION The results of this study demonstrate that patients with previous SOT who undergo elective primary TKA have more postoperative complications in the global period and at short-term follow-up. Yet, complication profiles by individual organ varied significantly.

Venous Thromboembolism Prophylaxis After TKA: Aspirin, Warfarin, Enoxaparin, or Factor Xa Inhibitors?

BackgroundThere is considerable debate regarding the ideal agent for venous thromboembolism (VTE) prophylaxis after TKA. Numerous studies and meta-analyses have yet to provide a clear answer and often omit one or more of the commonly used agents such as aspirin, warfarin, enoxaparin, and factor Xa inhibitors.Questions/PurposesUsing a large database analysis, we asked: (1) What are the differences in VTE incidence in primary TKA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors? (2) What are the differences in bleeding risk among these four agents? (3) How has use of these agents changed with time?MethodsWe queried a combined Humana and Medicare database between 2007 and Quarter 1 of 2016, and identified all primary TKAs performed using ICD-9 and Current Procedural Terminology codes. All patients who had any form of antiplatelet or anticoagulation prescribed within 1 year before TKA were excluded from our study cohort. We then identified patients who had either aspirin, warfarin, enoxaparin, or factor Xa inhibitors prescribed within 2 weeks of primary TKA. Each cohort was matched by age and sex. Elixhauser comorbidities and Charlson Comorbidity Index for each group were calculated. We identified 1016 patients with aspirin, and age- and sex-matched 6096 patients with enoxaparin, 6096 patients with warfarin, and 5080 patients with factor Xa inhibitors. Using ICD-9 codes, with the understanding that patients at greater risk may have had more-attentive surveillance, the incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications (bleeding requiring surgical intervention, hemorrhage, hematoma, hemarthrosis), postoperative anemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days postoperatively. A four-way chi-squared test was used to determine statistical significance. Utilization was calculated using compound annual growth rate.ResultsThere was a difference in the incidence of DVT at 90 days (p < 0.01). Factor Xa inhibitors (2.9%) had the lowest incidence of DVT followed by aspirin (3.0%) and enoxaparin (3.5%), and warfarin (4.8%). There was a difference in the incidence of PE at 90 days (p < 0.01). Factor Xa inhibitors (0.9%) had the lowest incidence of PE followed by enoxaparin (1.1%), aspirin (1.2%), and warfarin (1.6%). There was a difference in the incidence of postoperative anemia at 90 days (p < 0.01). Aspirin (19%) had the lowest incidence of postoperative anemia followed by warfarin (22%), enoxaparin (23%), and factor Xa inhibitors (23%). There was a difference in the incidence of a blood transfusion at 90 days (p < 0.01). Aspirin (7%) had the lowest incidence of a blood transfusion followed by factor Xa inhibitors (9%), warfarin (12%), and enoxaparin (13%). There were no differences in bleeding-related complications (p = 0.81) between the groups. Aspirin use increased at a compound annual growth rate of 30%, enoxaparin at 3%, and factor Xa inhibitors at 43%, while warfarin use decreased at a compound annual growth rate of -3%.ConclusionsFactor Xa inhibitors had the highest growth in utilization during our study period, followed by aspirin, when compared with enoxaparin and warfarin. When selected for the right patient, factor Xa inhibitors provided improved VTE prophylaxis compared with enoxaparin and warfarin, with a lower rate of blood transfusion. Aspirin provided comparable VTE prophylaxis compared with factor Xa inhibitors with improved VTE prophylaxis compared with enoxaparin and warfarin with the lowest risk of bleeding.Level of EvidenceLevel III, therapeutic study.

Analysis of complication rates following perioperative transfusion in shoulder arthroplasty

BACKGROUND Postoperative anemia requiring a blood transfusion is not uncommon following anatomic total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (RTSA). However, the potential complications in patients undergoing transfusion after shoulder arthroplasty remain unclear. The goal of this study was to examine the postoperative outcomes of patients receiving blood transfusions following TSA and RTSA. METHODS Using the Medicare Standard Analytic Files database, we identified all patients undergoing TSA or RTSA between 2005 and 2010. Using International Classification of Diseases, Ninth Revision, Clinical Modification and Current Procedural Terminology codes, we identified the procedure, transfusion status, comorbidities, and postoperative complications of interest. Odds ratios and 95% confidence intervals were calculated. RESULTS We identified 7,794 patients who received a perioperative blood transfusion following TSA or RTSA, as well as 34,293 age- and gender-matched controls, during the study period. Patients who received a perioperative transfusion had statistically significantly higher rates of myocardial infarction, pneumonia, systemic inflammatory response syndrome or sepsis, venous thromboembolic events, and cerebrovascular accidents at all time points in question. Patients who received a blood transfusion also showed an increased incidence of surgical complications, including periprosthetic infection and mechanical complications, up to 2 years postoperatively. CONCLUSION To our knowledge, this represents the largest study to examine the relationship between the need for perioperative blood transfusion and postoperative medical and surgical outcomes following TSA and RTSA. The results observed in this study highlight the importance of preoperative counseling and medical optimization prior to shoulder arthroplasty, particularly in patients with preoperative anemia or multiple medical comorbidities.

Metal-on-metal total hip arthroplasty is not associated with cardiac disease

Aims Many case reports and small studies have suggested that cobalt ions are a potential cause of cardiac complications, specifically cardiomyopathy, after metal‐on‐metal (MoM) total hip arthroplasty (THA). The impact of metal ions on the incidence of cardiac disease after MoM THA has not been evaluated in large studies. The aim of this study was to compare the rate of onset of new cardiac symptoms in patients who have undergone MoM THA with those who have undergone metal‐on‐polyethylene (MoP) THA. Patients and Methods Data were extracted from the Standard Analytics Files database for patients who underwent MoM THA between 2005 and 2012. Bearing surface was selected using International Classification of Diseases ninth revision codes. Patients with a minimum fiveyear follow‐up were selected. An age and gender‐matched cohort of patients who underwent MoP THA served as a comparison group. New diagnoses of cardiac disease were collected during the follow‐up period. Comorbidities and demographics were identified and routine descriptive statistics were used. Results We identified 29 483 patients who underwent MoM THA and 24 175 matched patients who underwent MoP THA. Both groups had a mean Charlson comorbidity index score of 4. There were no statistically significant differences in 30 of 31 pre‐existing comorbidities. Patients undergoing MoM THA had a slightly lower incidence of cardiac failure compared with those undergoing MoP THA at three years (6.60% versus 7.06%, odds ratio (OR) 0.93, 95% confidence interval (CI) 0.87 to 0.99) and four years (8.73% versus 9.49%, OR 0.91, 95% CI 0.86 to 0.97) postoperatively, with no difference in the incidence of new cardiac failure in between the groups at five years. There was no statistically significant difference in the incidence of arrhythmia, myocardial infarction and cardiomyopathy at any time between the two groups. Conclusion MoM THA is not associated with cardiac complications. Initial reports may have represented individual instances of cardiac disease in patients with a failing MoM articulation rather than an emerging epidemiological trend.

Total shoulder arthroplasty in patients with HIV infection: complications, comorbidities, and trends

BACKGROUND Patients with human immunodeficiency virus (HIV) infection were previously at substantial risk for immunosuppression-related complications. As a result of highly active antiretroviral therapy, HIV-infected patients are living longer and are presenting for elective surgery. Outcomes in HIV-infected patients are well described for hip and knee arthroplasty but not for total shoulder arthroplasty (TSA). The purpose of this study was to examine postoperative complications of TSA in HIV-positive patients. METHODS We queried the entire 2005 to 2012 Medicare database. Current Procedural Terminology and International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify the procedure, demographics, comorbidities, and postoperative complications. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. RESULTS The query returned 2528 HIV-positive patients who underwent TSA or reverse TSA (RTSA). There was increased utilization of TSA and RTSA in this population from 2005 to 2012; 1353 patients had 2-year follow-up. These patients were slightly older and had higher prevalence of comorbidities, suggesting a sicker cohort. HIV-positive patients had alarmingly higher rates of 90-day cerebrovascular accident (OR, 35.98; CI, 30.34-42.67). HIV-positive patients had higher overall rates of broken prosthetic joints (OR, 1.72; CI, 1.20-2.47), periprosthetic infection (OR, 1.36; CI, 1.01-1.82), and TSA revision or repair (OR, 2.44; CI, 1.81-3.28). CONCLUSIONS To our knowledge, this is the first study that directly examines the postoperative outcomes of HIV-positive patients after TSA or RTSA. As more of these patients present for surgery, surgeons should be aware that these patients might be at increased risk for certain postoperative surgical and medical complications.

Computer-Navigated Total Knee Arthroplasty Utilization.

Computer-navigated total knee arthroplasty (CN-TKA) has been used to improve component alignment, though the evidence is currently mixed on whether there are clinically significant differences in long-term outcomes. Given the established increased costs and operative time, we hypothesized that the utilization rate of CN-TKA would be decreasing relative to standard TKA in the Medicare population given the current health care economic environment. We queried 1,914,514 primary TKAs performed in the entire Medicare database from 2005 to 2012. Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes were used to identify and separate CN-TKAs. Utilization of TKA was compared by year, gender, and region. Average change in cases per year and compound annual growth rate (CAGR) were used to evaluate trends in utilization of the procedure. We identified 30,773 CN-TKAs performed over this time period. There was an increase in utilization of CN-TKA per year from 984 to 5,352 (average = 572/year, R (2) = 0.85, CAGR = 23.58%) from 2005 to 2012. In contrast, there was a slight decrease in overall TKA utilization from 264,345 to 230,654 (average = 4297/year, R (2) = 0.74, CAGR = - 1.69%). When comparing proportion of CN-TKA to all TKAs, there was an increase from 0.37 to 2.32% (average 0.26%/year, R (2) = 0.88, CAGR = 25.70%). CN-TKA growth in males and females was comparable at 24.42 and 23.11%, respectively. The South region had the highest growth rate at 28.76%, whereas the Midwest had the lowest growth rate at 15.51%. The Midwest was the only region that peaked (2008) with a slow decline in utilization until 2012. Despite increased costs with unclear clinical benefit, CN-TKA is increasing in utilization among Medicare patients. Reasons could include patient preference, advertising, proper of coding the procedure, and increased publicly available information about arthroplasty options.

Is Metal-On-Metal Total Hip Arthroplasty Associated With Neurotoxicity?

BACKGROUND Isolated case reports in the literature describe systemic neurologic side effects associated with metal-on-metal (MOM) bearing surfaces, yet the incidence of these effects have not been evaluated beyond individual cases. The purpose of this study was to compare new diagnoses of these side effects described in isolated cases in large patient cohorts of MOM vs metal on polyethylene (MOP). METHODS We queried the entire Medicare database from 2005 to 2012. Total hip arthroplasty (THA) and bearing surface were determined using International Classification of Diseases, 9th revision procedure codes. Patients with 5-year follow-up were selected. Using International Classification of Diseases, 9th revision codes, we identified new diagnoses of previously reported neurologic side effects: peripheral neuropathy, sensorineural hearing loss, visual impairment, paresthesias, tinnitus, and vertigo. Comorbidities and demographics were collected. Odds ratios, CIs, and P values were calculated. RESULTS Overall, 29,483 MOM THAs and 23,587 age- and gender-matched MOP THAs were identified. The average Charlson Comorbidity Index was 5 for both groups. MOM and MOP patients had 26 of 30 identical prevalence of Elixhauser-measure comorbidities. There was no statistically significant difference in new diagnoses of any of the side effects at any time point between the 2 groups over 5 years. CONCLUSION This study represents, to our knowledge, the first longitudinal analysis of systemic neurotoxicity after THA in a large cohort of patients. The results of our study suggest that on the large scale, neurologic side effects previously described do not occur as a common attributable complication. Rather, these cases may be due to individual patient hypersensitivity to metal ions.

Are factor Xa inhibitors effective thromboprophylaxis following hip fracture surgery?: A large national database study

INTRODUCTION The purpose of this study was to evaluate the effectiveness of Factor Xa inhibitors (XaI) for thromboprophylaxis following hip fracture surgery in a large cohort of patients, and compare XaI against warfarin and enoxaparin. METHODS Patients undergoing hip fracture surgery from 2007 to 2015 were identified in a large claims database. Patients prescribed warfarin, XaI, or enoxaparin within 2 weeks of surgery were identified and grouped into cohorts. Medical comorbidities and complication incidences, including deep venous thrombosis (DVT), pulmonary embolism (PE), and bleeding complications were calculated. Chi-square analysis was performed and adjusted residuals calculated to determine significant differences. RESULTS DVT rates were significantly different between groups at thirty days only (5.03% warfarin, 2.91% XaI, 3.48% enoxaparin, p=0.047). PE rates were significantly different at all time points; enoxaparin had the lowest rates. There were no differences in the rates of other complications. DISCUSSION XaI are an option for thromboprophylaxis in hip fracture patients, although their possible decreased effectiveness against PE compared to enoxaparin should be considered. CONCLUSIONS This study compares the effectiveness of Factor Xa inhibitors to warfarin and enoxaparin for hip fracture patients, using a large national database. In this study, Factor Xa inhibitors had similar effectiveness for DVT prophylaxis compared to these agents.