Sequentially Irradiated and Annealed Highly Cross-Linked Polyethylene: Clinical and Radiographic Outcomes in Total Knee Arthroplasty at 10-Year Follow-up.

Highly cross-linked polyethylene (HXLPE) has become the preferred bearing surface in total hip arthroplasty. However, its acceptance in total knee arthroplasty (TKA) has not been as robust because of concerns pertaining to wear and its impact on implant failure. Therefore, this multicenter study was purposed to evaluate the 10-year (1) radiographic outcomes; (2) complications; and (3) implant survivorship in patients with TKA receiving a sequentially irradiated and annealed HXLPE. A retrospective, multi-center study was performed on 139 patients (171 TKAs) who underwent primary TKA with HXLPE and possessed a minimum of 10-year follow-up. Radiographs were analyzed for radiolucencies along the implant-fixation interface using the Modern Knee Society Radiographic Evaluation System. Kaplan-Meier analysis determined implant survivorship when the end points were revision for polyethylene wear and polyethylene revision for any reason. Sixteen TKAs (9.9%) demonstrated periprosthetic linear radio-lucencies. Seventeen TKAs (9.9%) required additional surgeries, 9 (5.3%) of which were revisions, with 1 (0.6%) TKA requiring revision because of polyethylene wear. Other causes of revision included instability (1.8%), infection (1.6%), and arthrofibrosis (1.6%). The mean time to revision was 5.9 years (range, 0.1-11.1 years). Survivorship pertaining to polyethylene revision for wear was 99.4%, whereas all-cause polyethylene revision was 94.7%. This study in patients undergoing primary TKA using a second-generation HXLPE demonstrated excellent results with respect to polyethylene wear characteristics and strength with a 99.4% survivorship at 10 years. [Orthopedics. 2023;46(2):e111-e117.].

Sequentially Irradiated and Annealed Highly Cross-Linked Polyethylene: Linear Vector and Volumetric Wear in Total Hip Arthroplasty at 10 Years.

BACKGROUND: There is a paucity of data on the long-term performance of highly cross-linked polyethylene (HXLPE). Therefore, this study evaluated 10-year 1) functional, 2) radiographic, and 3) surgical outcomes in patients who underwent total hip arthroplasty with sequentially irradiated and annealed HXLPE. METHODS: A retrospective, multicenter study was conducted on patients who underwent primary total hip arthroplasty and received HXLPE polymer (n = 151). Two-dimensional radiographic linear and volumetric wear analyses were quantified using the Martell Hip Analysis software, while functional outcomes were assessed by analyzing postoperative Short-Form-12 (SF-12) Physical and Mental Health Surveys and Harris Hip Scores. Radiographic outcomes included yearly linear (mm/y) and volumetric (mm3/y) wear rates. Surgical outcomes included additional operations and survivorship. RESULTS: SF-12 scores were within 1 standard deviation (SD) of the normal population (SF-12 Physical: 47.0; SF-12 Mental: 52.0), while the Harris Hip Scores of 89.5 was borderline between "good" and "excellent." Total and annual linear wear rates were 0.164 mm (SD: 0.199 mm) and 0.015 mm/y (SD: 0.018 mm/y), respectively. The mean total volumetric wear rate was 141.4 mm3 (SD: 165.0) and 12.6 mm3/y (SD: 14.9 mm3/y) when broken down into a yearly rate. Eleven patients required revisions, resulting in an all-cause polyethylene survivorship of 92.7%, with a polyethylene wear survivorship of 100.0%. CONCLUSIONS: Our results demonstrate clinically undetectable linear and volumetric wear rates after 10 years in those who received the unique sequentially irradiated and annealed HXLPE. Furthermore, high rates of survivorship coupled with low all-cause revision rates illustrate the polymers' capability to potentially increase implant longevity.

Mid-Term Follow Up of Newer-Generation Morphometric Wedge Stems for Total Hip Arthroplasty (THA).

INTRODUCTION: Proximally coated, morphometric wedge femoral stems illustrated excellent survivorship and clinical outcomes at a minimum five-year postoperative follow up. MATERIALS AND METHODS: We completed a retrospective review of 186 THA patients from three high-volume surgeons to assess clinical- and patient-reported outcomes five years after implantation with a cementless, proximally coated morphometric wedge femoral stem. We reviewed Gruen zones on early postoperative and mid-term radiographs for signs of osteolysis, loosening, and wear. Clinical- and patient-reported outcomes were compared with previously published two-year outcomes for these femoral stems. RESULTS: No progression of radiolucencies or loosening was observed radiographically when comparing minimum one-year and five-year follow up. Reactive radiodense lines were observed in 23 cases (12.64%), and 13 cases (7.14%) exhibited true radiolucencies of 1-3mm, and all remained unchanged between follow ups or were no longer present on the five-year film. Cortical hypertrophy was noted in Gruen zones 3 and/or 5 in 11 cases (6.04%). No stems were revised for mechanical loosening or for periprosthetic fracture. Nine (9) patients (4.87%) underwent revisions during the follow-up period for periprosthetic infection, femoral head and/or acetabular component revisions, and impingement requiring release and femoral head change. Average Harris Hip Scores were excellent at five years and improved slightly when compared to a two-year follow up; however, this change was not statistically significant. Health-related quality of life mental component and physical component scores were a mean of 48.45 and 43.10 at 5 years, respectively. All cause Kaplan-Meier survivorship of the femoral stem was calculated at 98.4% at an average 65.7 months post implantation. Additionally, this cohort exhibited 100% aseptic survivorship during the follow-up period. CONCLUSION: Newer-generation morphometric wedge femoral stems for THA exhibit excellent radiographic stability, patient satisfaction, and clinical outcomes five years post implantation.

New Technology for Total Knee Arthroplasty Provides Excellent Patient-Reported Outcomes: A Minimum Two-Year Analysis.

INTRODUCTION: Robotic-assisted total knee arthroplasty has been demonstrated to help increase various patient-reported, clinical, and surgical outcome metrics (PROMs). However, the current literature is limited regarding PROMs data for longer follow-up periods beyond one year. Therefore, the purpose of this study was to 1) report multicenter patient-reported outcomes with multiple metrics, as well as 2) postoperative surgeon-specific outcomes at a minimum two-year follow-up. MATERIALS AND METHODS: Five fellowship-trained, high-volume surgeons performed a total of 188 total knee arthroplasty surgeries using the enhanced preoperative planning and real-time intraoperative feedback of a robotic-assisted device. Patients from all surgeons followed similar postoperative rehabilitation beginning on postoperative day one. Patients were evaluated based on the Short Form-12 Questionnaire (SF-12), the Forgotten Joint Score (FJS), and Knee Society total and subscores (KSS). The SF-12 was subdivided into two components: mental composite score (MCS) and physical composite score (PCS). The KSS was subdivided into functional and knee scores. Additionally, surgical outcomes from the latest follow-up visit were evaluated. All patients were evaluated at a minimum of two years follow-up time. RESULTS: All patients reported excellent postoperative outcomes for all three PROMs. The mean postoperative SF-12 MCS and PCS scores were both 57 points, with 50 as the threshold for norm-based scoring (MCS range: 42 to 69 points; PCS range: 41 to 68 points). The mean FJS was 75 points (range: 14 to 100 points). The mean KSS functional score was 84 points (range: 20 to 100) while the mean Knee Score was 92 points (range: 40 to 100). Similarly, we found that the aseptic revision rates were low (n=2, 1.06%, one for unexplained pain, and another for a post-traumatic tibial fracture) with few other postoperative complications (n=7 patients [3.7%]) in our cohort. CONCLUSION: Our analysis found that patients had excellent outcomes across multiple PROM metrics. Future work can build on these results with large patient populations over longer follow-up intervals. Nevertheless, these results provide the foundation and evidence to support the continued use of this innovative technology for total knee arthroplasties.

Manipulation Under Anesthesia Rates in Technology-Assisted versus Conventional-Instrumentation Total Knee Arthroplasty.

INTRODUCTION: Various technological advancements, specifically robotic assistance, have been implemented for total knee arthroplasty (TKA) procedures to attempt to improve patient outcomes and decrease complication rates. Manipulations under anesthesia have been considered a surrogate for knee stiffness, an undesired postoperative outcome that can potentially be avoided. Currently, there is a lack of information regarding the impact that these new technologies have on manipulations under anesthesia (MUA) rates following TKA. Therefore, the purpose of this study was to evaluate rates of MUAs between a consecutive series of patients who underwent robotic-assisted surgery compared to patients who underwent TKA with conventional instrumentation. MATERIALS AND METHODS: A total of 188 consecutive robotic-assisted total knee arthroplasties were performed by five fellowship-trained, high-volume surgeons at academic and community institutions. Patients were paired to a consecutive equal number of control patients by each of the specific surgeon for comparison. All patients followed similar postoperative rehabilitation starting on postoperative day one. Rates of MUAs were evaluated within and between cohorts. Additionally, the percent difference of rates was calculated to compare cohorts. All patients were evaluated at a minimum of two years follow-up time from the index procedure. Chi-square analyses was performed to statistically compare MUA rates between the cohorts. RESULTS: The overall manipulation under anesthesia rate for the study cohort was 1.06% (2/188 patients), while it was 4.79% in the control cohort (9/188) (p=0.032). A 127.5% difference in manipulation under anesthesia rates was found between the two cohorts. No individual surgeons had higher MUA rates in their robotic-assisted group. CONCLUSION: Our study found that patients undergoing robotic-assisted TKA experienced a significant, 4.5-fold decrease in rates of manipulation under anesthesia (p=0.032). Given that MUAs can be a marker of knee stiffness following total knee arthroplasty, the lower rate indicates that study cohort patients had less knee stiffness and, therefore, greater initial postoperative range of motion than the control cohort. Based on these data, assistive technologies may have an advantageous role contributing to enhanced patient outcomes.

A Comparative Effectiveness Study for Non-Operative Treatment Methods for Knee Osteoarthritis.

A number of non-operative treatment options are commonly prescribed for patients presenting with degenerative osteoarthritis of the knee, where surgery is not yet recommended. However, there is a paucity of studies evaluating the comparative effectiveness of these treatment options to best inform both patients and providers. This study examined the comparative effectiveness of a home exercise program versus bracing or a combination of the two (brace-only, exercise-only, and brace and exercise cohorts) on the following: 1) objective functional measures (quadriceps muscle strength, Self-Paced Walk Test [SPWT], and Timed "Up & Go" [TUG] Test); 2) subjective functional measures (Lower Extremity Function Scale [LEFS] and Health Survey [VR-12] outcomes); 3) pain using Visual Analog Scale [VAS-10]; 4) patient metrics (patient treatment preference, perceptions, and compliance); and 5) progression to total knee arthroplasty (TKA) over a 12-week period. Subjects exhibited significant improvements from baseline on all measures regardless of group assignment; however, the only significant difference between groups was the larger improvement in pain scores between the brace-only and the exercise-only cohorts (p = 0.022). The brace-only regimen may be more efficacious; however, larger studies are needed to confirm this. These findings suggest that patients who are provided with either treatment option may be able to achieve a better quality of life and return to activity that may delay an elective joint arthroplasty surgery.

The Role of Barbed Sutures in Wound Closure Following Knee and Hip Arthroplasty: A Review.

Lower extremity joint arthroplasty procedures often require a large incision to have an adequate exposure, which subsequently leads to lengthy wounds that may contribute to long closure, anesthesia, and overall operative times. The recently introduced knotless barbed suture may provide better outcomes, faster closure time, and decreased material utilization. Therefore, the aim of this study was to review the impact of barbed sutures on: (1) wound-related complications; (2) closure and operative time; (3) patient outcomes (range of motion and Knee Society Scores [KSS]); and (4) effects on cosmesis and patients' satisfaction. A literature search was performed using up to February 2017. Barbed sutures were associated with shorter closure times, shorter operative times, and larger cost savings per procedure as well as comparable wound complication rates after total joint arthroplasty. Although the current review is limited by the number of studies included, it demonstrates that overall, barbed sutures contribute to surgical efficiency when compared with conventional skin closure modalities.

Has Health Care Reform Legislation Reduced the Economic Burden of Hospital Readmissions Following Primary Total Joint Arthroplasty?

BACKGROUND: The purpose of this study was to determine whether the cost of readmissions after primary total hip and knee arthroplasty (THA and TKA) has decreased since the introduction of health care reform legislation and what patient, clinical, and hospital factors drive such costs. METHODS: The 100% Medicare inpatient dataset was used to identify 1,654,602 primary THA and TKA procedures between 2010 and 2014. The per-patient cost of readmissions was evaluated in general linear models in which the year of surgery and patient, clinical, and hospital factors were treated as covariates in separate models for THA and TKA. RESULTS: The year-to-year risk of 90-day readmission was reduced by 2% and 4% (P < .001) for THA and TKA, respectively. By contrast, the cost of readmissions did not change significantly over time. The 5 most important variables associated with the cost of 90-day THA readmissions (in rank order) were the nature of the readmission (ie, due to medical or procedure-related reasons), the length of stay, hospital's teaching status, discharge disposition, and hospital's overall total joint arthroplasty volume. The top 5 factors associated with the cost of 90-day TKA readmissions were (in rank order) the length of stay, hospital's teaching status, discharge disposition, patient's gender, and age. CONCLUSION: Although readmission rates declined slightly, the results of this study do not support the hypothesis that readmission costs have decreased since the introduction of health care reform legislation. Instead, we found that clinical and hospital factors were among the most important cost drivers.

Dual Mobility Acetabular Cups in Primary Total Hip Arthroplasty in Patients at High Risk for Dislocation.

INTRODUCTION: Postoperative dislocation occurs in approximately 2% of primary total hip arthroplasties (THAs). Risk factors associated with dislocation include: age of 70 years or older, body mass index (BMI) of 30 kg/m2 or greater, alcohol abuse, and neuro-degenerative diseases such as multiple sclerosis or Parkinson's disease. As a result, dual-mobility articulations, which have been typically used for revision procedures, have become an increasingly popular option for these "at risk" primary THAs. Few studies have assessed their use in this complex patient population. Therefore, the purpose of this study was to assess: 1) survivorship; 2) radiographic outcomes (cup migration, progressive radiolucencies, and changes in component position); 3) Harris Hip Scores; and 4) complications of the dual-mobility articulation in the setting of primary THA for patients at high risk for dislocation. MATERIALS AND METHODS: Five participating surgeons performed 495 primary cementless THAs between January 2011 and December 2013. During this time, four of the five surgeons used dual-mobility articulations whenever the acetabular cup size was 52 mm or greater to allow for a 28 mm head, while one surgeon used it when the cup size was less than 52 mm to allow for an effective head size of 38 mm. The remaining surgeon used it for all THAs. Of the 495 patients, 453 (92%) received dual-mobility articulations, of which, 43 patients (10%) were lost to follow-up before the two year minimum. The remaining 410 patients were further assessed to determine those who were considered high risk for dislocation (age = 70 years, BMI =30 kg/m2, had a diagnosis of alcohol abuse, or had a neuro-degenerative disorder). Two hundred forty-nine patients were included in the analysis (103 men, 146 women) who had a mean age of 66 years (range, 24 to 90 years). The mean follow-up was 3.3 years (range, 2 to 5 years). Kaplan-Meier analysis was performed to assess aseptic and all-cause acetabular cup survivorship. Radiographs were evaluated for cup migration, progressive radiolucencies, and any changes in component position. Clinical outcomes were assessed using the Harris Hip Score (HHS), and any surgery-related complications were recorded. RESULTS: The survivorship to aseptic failure (n= 1) and all-cause (aseptic, n= 1; septic, n= 1) Kaplan-Meier acetabular component survivorships were 99.6% (95% confidence interval [CI], 99.1% to 99.9%) and 99.2% (95% CI, 98.5% to 99.9%), respectively. One hip had impingement of an anteverted cup, resulting in trunnion notching, and required revision of the cup and stem. Another hip had a deep infection, which was treated with a two-stage revision procedure. There were no dislocations in this cohort. No progressive radiolucencies or component positional changes were seen on radiographic assessment. Patients reported a mean HHS of 92.5 (range, 47 to 100 points) at final follow-up. Surgical complications included one polyethylene liner that was incompletely seated, and one loose femoral stem, which required revision of only the femoral component. CONCLUSIONS: At short-term follow-up, dual-mobility articulations in primary THA offer survivorship, outcomes, and complications comparable to conventional THA designs in patients who are at increased risk for postoperative dislocation. Serious complications, such as polyethylene wear and intraprosthetic dislocations, have occasionally been reported with the use of these components. Therefore, future studies should be prospective, multi-center, and have longer-term follow-up to determine the true benefit of modular dual-mobility articulations in patients who are at high risk for dislocation.

Which Clinical and Patient Factors Influence the National Economic Burden of Hospital Readmissions After Total Joint Arthroplasty?

BACKGROUND: The Affordable Care Act of 2010 advanced the economic model of bundled payments for total joint arthroplasty (TJA), in which hospitals will be financially responsible for readmissions, typically at 90 days after surgery. However, little is known about the financial burden of readmissions and what patient, clinical, and hospital factors drive readmission costs. QUESTIONS/PURPOSES: (1) What is the incidence, payer mix, and demographics of THA and TKA readmissions in the United States? (2) What patient, clinical, and hospital factors are associated with the cost of 30- and 90-day readmissions after primary THA and TKA? (3) Are there any differences in the economic burden of THA and TKA readmissions between payers? (4) What types of THA and TKA readmissions are most costly to the US hospital system? METHODS: The recently developed Nationwide Readmissions Database from the Healthcare Cost and Utilization Project (2006 hospitals from 21 states) was used to identify 719,394 primary TJAs and 62,493 90-day readmissions in the first 9 months of 2013 based on International Classification of Diseases, 9th Revision, Clinical Modification codes. We classified the reasons for readmissions as either procedure- or medical-related. Cost-to-charge ratios supplied with the Nationwide Readmissions Database were used to compute the individual per-patient cost of 90-day readmissions as a continuous variable in separate general linear models for THA and TKA. Payer, patient, clinical, and hospital factors were treated as covariates. We estimated the national burden of readmissions by payer and by the reason for readmission. RESULTS: The national rates of 30- and 90-day readmissions after THA were 4% (95% confidence interval [CI], 4.2%-4.5%) and 8% (95% CI, 7.5%-8.1%), respectively. The national rates of 30- and 90-day readmissions after primary TKA were 4% (95% CI, 3.8%-4.0%) and 7% (95% CI, 6.8%-7.2%), respectively. The five most important variables responsible for the cost of 90-day THA readmissions (in rank order, based on the Type III F-statistic, p < 0.001) were length of stay (LOS), all patient-refined diagnosis-related group (APR DRG) severity, type of readmission (that is, medical- versus procedure-related), hospital ownership, and age. Likewise, the five most important variables responsible for the cost of 90-day TKA readmissions were LOS, APR DRG severity, gender, hospital procedure volume, and hospital ownership. After adjusting for covariates, mean 90-day readmission costs reimbursed by private insurance were, on average, USD 1324 and USD 1372 greater than Medicare (p < 0.001) for THA and TKA, respectively. In the 90 days after TJA, two-thirds of the total annual readmission costs were covered by Medicare. In 90 days after THA, more readmissions were still associated with procedure-related complications, including infections, dislocations, and periprosthetic fractures, which in aggregate account for 59% (95% CI, 59.1%-59.6%) of the total readmission costs to the US healthcare system. For TKA, 49% of the total readmission cost (95% CI, 48.8%-49.6%) in 90 days for the United States was associated with procedure issues, most notably including infections. CONCLUSIONS: Hospital readmissions up to 90 days after TJA represent a massive economic burden on the US healthcare system. Approximately half of the total annual economic burden for readmissions in the United States is medical and unrelated to the joint replacement procedure and half is related to procedural complications. CLINICAL RELEVANCE: This national study underscores LOS during readmission as a primary cost driver, suggesting that hospitals and doctors further optimize, to the extent possible, the clinical pathways for the hospitalization of readmitted patients. Because patients readmitted as a result of infection, dislocation, and periprosthetic fractures are the most costly types of readmissions, efforts to reduce the LOS for these types of readmissions will have the greatest impact on their economic burden. Additional clinical research is needed to determine the extent to which, if any, the LOS during readmissions can be reduced without sacrificing quality or access of care.

Novel venous thromboembolic disease (VTED) prophylaxis for total knee arthroplasty-aspirin and fish oil.

BACKGROUND: Despite the demonstrated success of multiple anticoagulation therapies for post-operative prophylaxis of thromboembolic disease in lower extremity arthroplasties, each modality comes with a unique set of limitations. Thus, the ideal anticoagulation medication which provides adequate therapy with minimal cost, complications, or added patient work is yet to be defined. One promising novel thrombophylactic supplement is fish oil, as many preliminary clinical trials have demonstrated a protective effect of fish oil against thrombosis in multiple clinical settings. In addition, others have demonstrated synergistic effect when combined with aspirin. However, there are paucity of studies that compared combined aspirin and fish oil therapy for venous thromboembolism prophylaxis with other pharmacological agents, especially in the field of orthopaedics. Therefore, this study evaluated: (I) risk of post-operative deep vein thrombosis (DVT) and pulmonary embolism (PE), and (II) bleeding complications; among patients who had primary total knee arthroplasty (TKA) and received one of the following regimens: (i) 325 mg aspirin and mechanical pulsatile stocking; (ii) rivaroxaban; or (iii) 325 mg aspirin and 1,000 mg fish oil. METHODS: This was a 6-year prospective study analyzing the postoperative thromboembolic prophylaxis received by patients who underwent primary TKA. Patients who had a previous history of thromboembolic disease were excluded from the study due to an increased risk of recurrent clot formation. A total of 850 patients were enrolled. A total of 300 patients enrolled between October 2011 and June 2013 received 325 mg aspirin and mechanical pulsatile stocking, while 250 patients enrolled between June 2013 and December 2014 received rivaroxaban. A total of 300 patients enrolled between January 2015 and July 2017 received 325 mg aspirin and 1,000 mg fish oil. Major venous thromboembolic events (VTEs) and bleeding complications within the first 90 days post-operatively were recorded in each cohort. The odds ratios (ORs) and 95% confidence intervals (CIs), for thromboembolic and bleeding events were calculated and compared between the aspirin and fish oil cohort vs. aspirin and pulsatile stocking cohort, and aspirin and fish oil cohort vs. rivaroxaban cohort. A P value of <0.05 was used to determine statistical significance. RESULTS: A total of 25 DVT events were recorded including 1 of 300 (0.33%) in the aspirin and fish oil cohort, 22 of 300 (7.33%) in the aspirin and pulsatile stocking cohort and 2 of 250 (0.8%) in the rivaroxaban cohort. When comparing ORs, patients who received aspirin and fish oil demonstrated significantly lower risk for thromboembolic events when compared to the aspirin and pulsatile stocking group (OR: 0.045; 95% CI: 0.0061-0.3394; P<0.05). When compared to the rivaroxaban cohort the ORs did not differ significantly (OR: 0.416; 95% CI: 0.0376-4.6223; P>0.05). In addition, no PE events were recorded in any of the cohorts. When compared to rivaroxaban, the fish oil and aspirin cohort demonstrated significantly lower incidence of bleeding episodes (1 of 300, 0.33% vs. 30 of 250 patients, 12%; OR: 0.0278; 95% CI: 0.0038-0.2051; P<0.05). No bleeding events were recorded in the aspirin and pulsatile stocking cohort. CONCLUSIONS: This study demonstrated the potentially synergistic anti-thromboembolic effect of aspirin and fish oil in the prevention of post-operative venous thromboembolism in primary TKA patients. Based on the results from this study, the authors conclude that the combination of aspirin and fish oil maybe an excellent thromboprophylactic modality for patients to use after TKA. These results warrant further, larger prospective studies analyzing the use of fish oil supplements in VTE prophylaxis.

Which Hospital and Clinical Factors Drive 30- and 90-Day Readmission After TKA?

BACKGROUND: The purpose of this study was to analyze the hospital, clinical, and patient factors associated with inpatient readmission after total knee arthroplasty (TKA) in the Medicare population and to understand the primary reasons for readmission. METHODS: The Medicare 100% national hospital claims database was used to identify 952,593 older patients (65+) with a primary TKA in 3848 hospitals between 2010 and 2013. A multilevel logistic regression analysis with a clustered data structure was used to investigate the risk of all-cause 30- and 90-day readmission, incorporating hospital, clinical, and patient factors. RESULTS: At 30 days, readmission ranged from 0% to 22% (median, 4.9%), whereas at 90 days, readmission ranged from 0% to 32% (median, 8.6%). Geographic census region, hospital procedure volume, rural hospital location, and nonprofit ownership were the only significant hospital factors among those we studied. Evaluation of clinical factors showed use of a perioperative transfusion was associated with 13% greater risk; patients discharged to home had 25% lower risk; and surgeon volume and length of stay were also significant. These effect sizes were at least comparable to patient factors, such as age, gender, comorbidities, and socioeconomic status. The top 5 most frequently reported primary reasons for 30- or 90-day readmission in TKA were surgery and medical related: wound infection, deep infection, atrial fibrillation, cellulitis and abscess of leg, or pulmonary embolism. CONCLUSION: The results of this study support further optimization of anti-infection measures, both intraoperative and postoperative, to reduce the broad variation in hospital readmissions.

Hospital, Patient, and Clinical Factors Influence 30- and 90-Day Readmission After Primary Total Hip Arthroplasty.

BACKGROUND: The purpose of this study was to analyze the hospital, clinical, and patient factors associated with inpatient readmission after total hip arthroplasty (THA) in the Medicare population and to understand the primary reasons for readmission. METHODS: The Medicare 100% national hospital claims database was used to identify 442,333 older patients (65+) with a primary THA in 3730 hospitals between 2010 and 2013. A multilevel logistic regression analysis with a clustered data structure was used to investigate the risk of all-cause 30- and 90-day readmission, incorporating hospital, clinical, and patient factors. RESULTS: At 30 days, 5.8% (median) of the patients were readmitted, whereas at 90 days, 10.5% (median) were readmitted. Geographic census region, hospital procedure volume, and nonprofit ownership were the only significant hospital factors among those we studied. Overall, clinical factors explained more of the variation in readmission rates than general hospital factors. Use of a perioperative transfusion was associated with 14% greater risk, patients discharged to home had 28% lower risk, and surgeon volume and length of stay were also significant risk factors. The top 5 most frequently reported primary reasons for 30-day readmission in THA were procedure related: dislocation (5.9%), deep infection (5.1%), wound infection (4.8%), periprosthetic fracture (4.4%), or hematoma (3.4%). CONCLUSION: These findings support further optimization of the delivery of care-both intraoperative and postoperative-to reduce the broad variation in hospital readmissions.

Outcomes of Second-Generation Tapered Wedge Femoral Stem.

INTRODUCTION: Newer generation cementless femoral stems have been designed to emulate more precisely the anatomy of the native femur. However, few studies have evaluated these designs. The purpose of this study was therefore to evaluate outcomes of primary total hip arthroplasty (THA) in patients who received a second-generation, tapered wedge stem by analyzing (1) all-cause and aseptic implant survivorships; (2) clinical and patient-reported outcomes; (3) radiographic outcomes; and (4) incidence of complications. MATERIALS AND METHODS: We evaluated 202 primary THA patients (37% men, 63% women) who had a mean age of 63 years (range, 18 to 88) and a mean body mass index (BMI) of 29 (range, 18 to 40). All patients underwent THA using a press-fit, tapered wedge stem with a morphometric design containing a size-specific medial curvature, which optimizes initial press-fit stability. Kaplan-Meier analysis was performed to determine implant survivorship, and Harris Hip Scores (HHS) and the Short form-36 (SF-36) were used to evaluate clinical and patient-reported outcomes. Early postoperatively and annually thereafter, pelvic radiographs were reviewed for evidence of osteolysis or loosening. Complications were identified through a comprehensive chart review and were classified as either surgical or medical. RESULTS: At final follow-up, the all-cause and aseptic survivorships for the femoral stem were 99.5% and 100%, respectively. At final follow-up, the mean HHS was 87 (range, 35 to 100). The SF-36 mental and physical component scores were 47 (range, 19 to 65) and 47 (range, 23 to 65), respectively, at final follow-up. No progressive radiolucencies or loosening were observed. Surgical complications included nerve palsy, posterior trochanteric avulsion, arthrofibrosis, and periprosthetic fracture. The only medical complication was acute renal failure. CONCLUSION: This second-generation stem demonstrated excellent short-term survivorship and functional outcomes. The improved patient fit of this stem may yield continued favorable results with longer-term follow-up.

Low Frequency of Early Complications With Dual-mobility Acetabular Cups in Cementless Primary THA.

BACKGROUND: Dislocation complicates 1% to 5% of primary total hip arthroplasties (THAs). As a result, some surgeons consider dual-mobility articulations, which are usually used in the revision setting to decrease the likelihood of dislocation, as an option for primary THA. However, few studies have evaluated their use in this setting. QUESTIONS/PURPOSES: (1) What is the cup survivorship when the dual-mobility articulation is used in the setting of primary THA? (2) What are the clinical outcomes with this approach? (3) What are the radiographic outcomes? (4) What are the complications of dual-mobility articulations in primary THA? METHODS: Between 2011 and 2013, the five participating surgeons performed 495 cementless primary THAs. During that time, one of the five surgeons used dual-mobility articulations for all THAs, and the other four used it whenever the acetabular cup size was 52 mm or greater to enable a 28-mm head. Of the 495 patients, 453 (92%) were performed using this device. Smaller patients were treated with a standard THA. Of the 453 patients, a total of 43 patients (10%) were lost to followup before the 2-year minimum. The resulting 410 patients who were included in the analysis (164 men, 246 women) had a mean age of 64 years (SD, 12 years). The mean followup was 3 years (SD, 0.7 years). We performed Kaplan-Meier analyses to assess survivorship to aseptic failure and all-cause acetabular component survivorship. Clinical outcomes were evaluated using the Harris hip score (HHS); radiographs were assessed for cup migration, progressive radiolucencies, and positional changes of the components; and any surgery-related complications were recorded. RESULTS: The survivorship to aseptic failure and all-cause acetabular component survivorship was 99.8% (failures, n = 1) (95% confidence interval [CI], 4.517-4.547) and 99.3% (failures, aseptic, n = 1; septic, n = 2) (95% CI, 4.494-4.543); one hip had trunnion notching caused by impingement of a malpositioned cup, which was treated with revision of the cup and stem; and two patients had periprosthetic infections that were treated with two-stage revisions. There were no dislocations. Patients had a mean HHS of 94 (SD, 6) at final followup. On radiographic evaluation, no progressive radiolucencies or positional changes of the components were identified. Surgical complications included one traumatic avulsion of the abductors, one traumatic avulsion of the greater trochanter, which was repaired without revision of any of the components, and one loose femoral stem, which required revision of the femoral component only. CONCLUSIONS: Dual-mobility cups in primary THA yield seemingly comparable survivorship and complications to conventional THA bearings at short-term followup. Because serious complications have occasionally been reported with the use of these bearings, larger, longer term, comparative-and ideally, randomized-trials will be needed to establish the superiority of one approach over the other. Until or unless such studies show the superiority of dual-mobility designs for primary THA, we recommend that in the setting of uncomplicated primary THA, dual-mobility articulations be used only in centers that track their results carefully or in research protocols. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Minimum 5-year follow-up for primary THA using a tapered, proximally coated cementless stem.

The purpose of this study was to assess the survivorship of a proximally coated, cementless femoral stem used for total hip arthroplasty at a minimum 5-year follow-up by assessing clinical outcomes and implant survival. A total of 936 primary total hip arthroplasties were performed in 854 patients by 3 high-volume surgeons between 2001 and 2007. Patients included 385 men and 469 women with a mean age of 56 years (range, 20-88 years) and a mean follow-up of 7 years (range, 5-11 years). The aseptic revision rate related to the femoral component was 0.3%. Three patients underwent revision of the femoral component. Mean postoperative Harris Hip Score improved to 91 points (range, 70-100 points). When stratified by primary cause of total hip arthroplasty, no differences were found in implant survivorship or postoperative Harris Hip Scores. With the exception of the 3 patients who underwent revision surgery, postoperative radiographic evaluation of the stems demonstrated no progressive radiolucencies, component malalignment, change in component position, or implant subsidence at most recent follow-up.These results are encouraging and indicate a 0.3% revision rate for the femoral component. The cause of primary total hip arthroplasty did not affect the clinical outcomes. These types of prostheses will provide patients with a stable implant that is expected to have excellent durability and longevity.

Patellofemoral arthroplasty: 7-year mean follow-up.

Patellofemoral arthroplasty has had renewed interest with the purpose of this study to evaluate its outcomes. Between 2001 and 2006, 43 were performed in 37 patients who had a mean follow-up of 7 years (range, 4-8 years). Patient outcomes were determined using Knee Society objective and function scores, revision rates, and complication rates. The 5-year Kaplan-Meier survivorship was 95%. Knee Society objective scores improved from a mean of 64 points (range, 57-68 points) to 87 points (range, 50-100 points), and functional scores improved from a mean of 48 points (range, 45-50 points) to 82 points (range, 20-100 points). This study shows maintained successful clinical and radiographic results at mean 7-year follow-up for patellofemoral arthroplasty.

A Comparison Study of Two Cruciate-Retaining Total Knee Designs: A Preliminary Report.

Cruciate-retaining total knee arthroplasties have had high success rates. The purpose of this study was to compare a newer cruciate-retaining design to a previously used implant to determine if there were any changes in clinical or functional outcome. A total of 461 patients (553 knees) were identified who had total knee arthroplasty with this newer design. At latest 2-year follow-up, the mean range of motion was 121 degrees (range 105 to 140 degrees), the mean Knee Society pain score was 91 points (range, 57 to 100 points) and the functional score was 76 points (45 to 100 points). The comparison group of 211 patients (225 knees) had a mean range of motion of 119 degrees at 2 years (range, 90 to 142 degrees) with Knee Society pain and functional scores of 95 and 85 points, respectively (ranges 57 to 100, and 0 to 100, respectively). The use of the newer cruciate-retaining total knee arthroplasty showed comparable results to the previously used design at short-term follow-up. The cruciate-retaining design used in this study had no early failures, though further study is needed to make assessments regarding longer-term functional results and outcomes.

Does functional improvement following TKA correlate to increased sports activity?

Improved TKA designs and surgical techniques have allowed surgeons to not only treat the pain associated with osteoarthritis but also to restore function. The present study analyzed whether the increase in physical activity of patients following surgery is associated with their level of functional and objective improvement. An activity questionnaire was utilized to collect pre- and post-operative information from 355 patients (417 knees). Corresponding functional and objective assessments were collected using the Knee Society rating system. Overall, a mean 48 point (range, -44 to 97 points) improvement in Knee Society function score showed moderate correlation to a 2.5 point (range, -40 to 57 points) increase in weighted activity score (R = 0.362). There was less of a correlation between the mean objective score increase of 49 points (-32 to 84 points) and change in activity level (R = 0.194). There were 29% of the patients who showed no change in activity level. These results suggest that change in activity level is more closely associated with improved function than changes in objective measures. With more than 52% of TKA patients reporting increased activity scores, further studies are needed to assess longer-term effects of activity levels on the durability of these prostheses.