The impact of prior ACL reconstruction on total knee arthroplasty outcomes: a retrospective matched cohort study.

INTRODUCTION: Discrepant data exists regarding the outcomes following total knee arthroplasty (TKA) with a prior anterior cruciate reconstruction (ACLR). The purpose of our study was to compare surgical and medical outcomes in the patients with prior ACLR undergoing TKAs compared to a matched control group of the patients who had undergone TKAs without prior ACLR. We hypothesized that the patients with prior ACLR would have inferior clinical outcomes. MATERIAL/METHODS: We retrospectively queried the PearlDiver-database for patients who underwent TKA following ACLR from 2011 to 2020. We used propensity-score matching to create two cohorts. The two-sided independent t-test and Chi-Squared test were used. RESULTS: We identified 2,174 patients who had prior ACLR before the TKAs. There were another 1,348,870 patients who did not have ACLR before the TKAs. After matching, each group had 2,171 patients. The ACLR-TKA group had significantly lower rates of aseptic revision at 2 years (1.2% vs. 4.0%, OR 0.3, p < 0.01), PJI requiring antibiotic spacer at 2 years (0.3% vs. 0.8%, OR 0.35, p = 0.02), and MUA at 90 days (0.4% vs. 7.5%, OR 0.05, p < 0.01). The rate of wound disruption was lower for the ACLR-TKA group at 90 days (p = 0.03) as were several medical complications including AKI at 90 days (p < 0.01), DVT at 90 days (p < 0.01), pneumonia at 90 days (0.04), and required blood transfusion at 90 days (p < 0.01). CONCLUSION: These results differed from our expectations. Within the limitations of the study, we are unable to determine the factors for the lower complications in the ACLR-TKA group. The data from this study are different from what had been reported in the previous studies.

Tapered vs Cylindrical Stem Fixation in a Model of Femoral Bone Deficiency in Revision Total Hip Arthroplasty.

BACKGROUND: Distal fixation achieved with a tapered stem design has demonstrated favorable clinical results in revision total hip arthroplasty in the setting of severe bone defects. However, stem subsidence is common with this stem design. PURPOSE: The purpose of this study is to compare the initial fixation stability of a tapered stem design to a fully porous-coated cylindrical stem design in a model of severe femoral bone deficiency. METHODS: Tapered and cylindrical stems (n = 8) were implanted into a model femur with progressively shorter segments for fixation (9, 6, or 3 cm). The stems were axially loaded, and the force to produce subsidence was recorded. RESULTS: Average loads to produce 150 µm of displacement with a 3-cm segment were higher for the tapered stem (393 N vs 221 N, P < .01). No difference was observed in the 6- or 9-cm models. Average loads to produce failure (>4-mm subsidence) were also higher for tapered stems with a 3-cm segment (1574 N vs 500 N, P < .0001). A regression analysis determined the minimum segment length of 1.5-2.5 cm to obtain stable fixation with a tapered stem design (R(2) = 0.78, P < .001). CONCLUSIONS: Tapered stems required higher loads to produce subsidence than cylindrical stems in a revision THA model. Revision tapered stems require a minimum intact segment of 1.5-2.5 cm to obtain adequate initial fixation stability. Revision tapered stems have superior initial fixation stability to cylindrical stems in the setting of severe bone loss.

Preoperative flexion does not influence postoperative flexion after rotating-platform total knee arthroplasty.

PURPOSE: Preoperative range of motion (ROM) has been regarded as one of the most important factors in predicting postoperative ROM following total knee arthroplasty (TKA). Mobile-bearing TKA designs have been suggested to possibly improve the knee kinematics compared to fixed-bearing designs. The purpose of this study was to examine the difference in postoperative flexion as a function of preoperative flexion in a consecutive series of TKAs done using a posterior-stabilized rotating-platform prosthesis. METHODS: ROM was assessed in 153 consecutive TKAs done using a rotating-platform posterior cruciate-substituting design. Patients were divided into two groups based on their preoperative ROM (Group 1 < 95°, Group 2 > 95°). The Knee Society Score (KSS) and ROM were assessed preoperatively, 3 months and 12 months postoperatively. RESULTS: There was no difference in flexion 12 months after surgery between groups (mean 120° and 123°, respectively. n.s.). After 3 month follow-up, no increase in ROM was experienced by either group. Patients in Group 1 experienced significantly greater increases in both ROM (p < 0.001) and KSS (p < 0.05). There was no difference in the KSS at 12 months after surgery between groups. CONCLUSION: In this series of patients undergoing TKA with a rotating-platform prosthesis, the preoperative ROM was not predictive of the postoperative ROM. Patients with stiff knees preoperatively may benefit from a mobile-bearing design prosthesis.

Apixaban and rivaroxaban decrease deep venous thrombosis but not other complications after total hip and total knee arthroplasty.

Apixaban and rivaroxaban are oral direct factor Xa (FXa) inhibitors used for VTE prevention after total hip (THA) and total knee arthroplasty (TKA). A meta-analysis of level I studies comparing rivaroxaban 10 mg daily or apixaban 2.5 mg twice daily to enoxaparin for the prevention of VTE after THA or TKA was performed analyzing efficacy and safety outcomes. Seven studies met the inclusion criteria including 24,385 patients. Oral FXa inhibitors were superior to enoxaparin in preventing DVT (p<0.00001). There was no difference in the rate of PE, death, major bleeding, blood transfusion requirement, reoperation for bleeding or postoperative wound infections. Oral FXa inhibitors are superior to enoxaparin in preventing DVT after THA and TKA. There is no difference in the rate of PE, death, or postoperative wound complications.

Total Hip Arthroplasty in Nonagenarians - A National In-Patient Sample-Based Study of Perioperative Complications.

Background: Nonagenarians are a rapidly expanding population in the United States. These patients are met with increasing rates of hip arthritis, necessitating the need for total hip arthroplasty (THA). However, there is currently limited information on hospitalization information and perioperative complications in this population. Methods: In this retrospective study, we used the Nationwide Inpatient Sample (NIS) database from 2016-2019 to analyze the incidence of perioperative complications, length of stay (LOS), and the cost of care (COC) among patients undergoing THAs who were categorized as nonagenarians, and those who were not. Results: The NIS database identified 309 100 patients who underwent THAs from 2016-2019. Of those, 1864 patients (.6%) were nonagenarian, while the remaining 307 236 patients were included under the non-nonagenarian category (control). The mean age in the nonagenarian group was 90 years compared to the control group which had a mean age of 65.8 years. There was an increased incidence of mortality rate (nonagenarian group .2%, control group .03%, P < .001), myocardial infarction (MI) (nonagenarian group .1%, control group .02%, P = .01), acute renal failure (ARF) (nonagenarian group 5.4%, control group 1.6%, P < .001), blood anemia post-operatively (nonagenarian group 28.9%, control group 17.2%, P < .001), and deep vein thrombosis (DVT) (nonagenarian group .48%, control group .07%, P < .001) in the nonagenarian group. The COC for the nonagenarian group was higher than that in the control group (P < .001). The mean LOS was longer in the nonagenarian group (3.1 days) in comparison to the control group (1.96 days) (P < .001). Conclusions: Nonagenarians had significantly higher rates of both orthopedics and medical complications than the younger patients undergoing THAs. In addition, the nonagenarian group incurred higher COC. This information is useful for the providers to make informed decisions regarding patient care and resource utilization for nonagenarian patients undergoing THAs.

Complications of primary total hip arthroplasty in human immunodeficiency virus-positive patients with femoral head osteonecrosis.

BACKGROUND: Femoral head osteonecrosis (FHON) is a well-recognised complication in patients with human immunodeficiency virus (HIV) infection. Total hip arthroplasty (THA) is a reliable solution to FHON and has provided functional improvement and pain relief in these patients. Higher complication rates, in particular infections, have been reported in the series of THAs done in the HIV-positive patients. The purpose of this study was to evaluate the complication rate of THA for FHON in HIV-positive patients managed with the highly active antiretroviral therapy (HAART) protocols. METHODS: A retrospective review was performed of HIV-positive patients with FHON who underwent THAs over a 10-year period at a single institution. RESULTS: A total of 56 THAs (44 patients) met the inclusion criteria. The mean age at the time of THAs was 47 (range 34-60) years. Of the 44 patients, 39 (88.6%) were males. The mean follow-up was 6.6 (range 2.0-11.3) years. The overall complication rate was 12.5%, with 2 (3.6%) cases of deep periprosthetic infections. CONCLUSIONS: HIV-positive patients with FHON undergoing THAs do have a considerable complication rate (12.5%). The deep periprosthetic infection rate (3.6%) in these patients, however, has decreased with contemporary disease modification protocols.

The eighth American college of chest physicians guidelines on venous thromboembolism prevention: implications for hospital prophylaxis strategies.

Venous thromboembolism (VTE) is the most common potentially preventable form of hospital-related mortality. It presents as a major healthcare burden, affecting both medical and surgical patients. The prevention of VTE has been identified as one of the most important in-hospital safety practices in the US. VTE guideline recommendations provide a framework for clinical practice and guide VTE prophylaxis policies. Guidelines produced by the American College of Chest Physicians (ACCP) are considered to be the 'gold standard' in VTE prevention, diagnosis and management, and have been updated. A number of differences exist between the new 2008 ACCP guidelines on VTE prevention and the previous version published in 2004. There are variations regarding VTE prevention, including new and stronger evidence-based recommendations for several indications and agents. The updated guidelines give a strong recommendation that every hospital develop a VTE prevention policy, which is particularly important given the current international drive to reduce the incidence of VTE. A formal hospital policy should help improve compliance with appropriate VTE prophylaxis strategies. The ACCP guidelines form a basis for improving patient safety at a time of public reporting of quality of care, hospital accreditation, national standards of care, and pay for performance initiatives. In this review, changes in recommendations for VTE prevention in the 2008 ACCP guidelines compared with the previous edition in 2004 are outlined. In addition, outstanding areas of debate are discussed and the role of the 2008 ACCP guidelines in the context of the new VTE performance measures analyzed.

Total hip arthroplasty in the ankylosed hip.

Altered biomechanics secondary to hip ankylosis often result in degeneration of the lumbar spine, ipsilateral knee, and contralateral hip and knee. Symptoms in these joints may be reduced with conversion total hip arthroplasty (THA) of the ankylosed hip. THA in the ankylosed hip is a technically challenging procedure, and the overall clinical outcome is generally less satisfactory than routine THA performed for osteoarthritis and other etiologies. Functional integrity of the hip abductor muscles is the most important predictor of walking ability following conversion THA. Many patients experience persistent limp, and it can take up to 2 years to fully assess final functional outcome. Risk factors cited for increased risk of failed THA include prior surgical ankylosis and age <50 years at the time of conversion THA.

Standardized total knee arthroplasty pathway improves outcomes in minority patients.

OBJECTIVES: Inferior total knee arthroplasty (TKA) outcomes are reported in minority populations. Standardized TKA pathways improve outcomes but have not been studied extensively in minority populations. This study evaluated the impact of TKA pathway standardization at an urban teaching hospital that predominantly treats minority patients. STUDY DESIGN: Retrospective cohort study. METHODS: This study compared primary TKA outcomes before and after implementation of a standardized multidisciplinary pathway that emphasized preoperative education and discharge planning, preemptive multimodal pain control, and early rehabilitation. Patients were grouped as "nonpathway" (n = 144) or "pathway" (n = 182) based on whether they underwent TKA before or after pathway implementation. Outcomes included length of stay (LOS), patient-controlled analgesia (PCA) use, blood transfusion, postoperative hemoglobin, complications, and discharge disposition. Analysis involved negative binomial and multiple logistic regression models, t tests, and Fisher's exact tests. RESULTS: Mean (SD) age was 61.6 (8.7) years, and 36.5% were men. Ethnicity of the patients included Hispanic (44.5%), African American (27.9%), Asian (14.1%), and White (12.9%). Pathway and nonpathway patients were similar demographically and racially. Pathway patients had shorter LOS (P = .04), less PCA use (P < .001), more frequent discharge home (P = .03), fewer transfusions (P = .002), and higher postoperative hemoglobin (P < .001). Overall incidence of complications was similar (P = .61). Nonpathway patients developed more cardiopulmonary complications (P = .02), whereas pathway patients had more wound dehiscence (P = .01). CONCLUSIONS: Compared with nonpathway patients, standardized TKA pathway patients had shorter LOS, decreased PCA use, increased discharge to home, fewer blood transfusions, and higher postoperative hemoglobin, with no difference in total incidence of complication.

Sources of contamination in the operating room: A fluorescent particle powder study.

This study utilized fluorescent particle powder to investigate 2 potential sources of sterile field contamination in the operating room (OR): forced-air warming blankets and OR light manipulation. In part 1, sterile draping for knee replacement surgery was performed on a mannequin in a sterile OR, comparing field contamination with the forced-air warming on versus off during draping. In part 2, OR lights coated with fluorescent powder were manipulated over a sterile field. Proper operation of these devices may reduce the particle burden on the surgical field.

A randomized evaluation of betrixaban, an oral factor Xa inhibitor, for prevention of thromboembolic events after total knee replacement (EXPERT).

Betrixaban is an oral direct inhibitor of factor Xa (FXa) being developed for the prevention of venous thromboembolism (VTE). Its antithrombotic effects had not been previously tested in patients. This exploratory clinical trial in the US and Canada randomized 215 patients undergoing elective total knee replacement (TKR) in a 2:2:1 ratio to receive post-operative betrixaban 15 mg or 40 mg p.o. bid or enoxaparin 30 mg s.c. q12h, respectively, for 10-14 days. The betrixaban dosage was blinded, but enoxaparin was not. Primary efficacy outcome was the incidence of VTE, consisting of deep-vein thrombosis (DVT) on mandatory unilateral (operated leg) venography, symptomatic proximal DVT, or pulmonary embolism (PE) through Day 10-14. Safety outcomes included major and clinically significant non-major bleeds through 48 h after treatment. All efficacy and bleeding outcomes were adjudicated by a blinded independent central adjudication committee. Of 214 treated patients, 175 (82%) were evaluable for primary efficacy. VTE incidence was 14/70 (20%; 95% CI: 11, 31) for betrixaban 15 mg, 10/65 (15%; 95% CI: 8, 27) for betrixaban 40 mg, and 4/40 (10%; 95% CI: 3, 24) for enoxaparin. No bleeds were reported for betrixaban 15 mg, 2 (2.4%) clinically significant non-major bleeds with betrixaban 40 mg, and one (2.3%) major and two (4.6%) clinically significant non-major bleeds with enoxaparin. A dose- and concentration-dependent effect of betrixaban on inhibition of thrombin generation and anti-Xa levels was observed. Betrixaban demonstrated antithrombotic activity and appeared well tolerated in knee replacement patients at the doses studied.

Oral thrombin inhibitor dabigatran etexilate vs North American enoxaparin regimen for prevention of venous thromboembolism after knee arthroplasty surgery.

Dabigatran, an oral once-daily unmonitored thrombin inhibitor, has been tested elsewhere using enoxaparin 40 mg once daily. We used the North American enoxaparin 30 mg BID regimen as the comparator. This was a double-blind, centrally randomized trial. Unilateral total knee arthroplasty patients were randomized to receive oral dabigatran etexilate 220 or 150 mg once daily, or enoxaparin 30 mg SC BID after surgery, blinded. Dosing stopped at contrast venography, 12 to 15 days after surgery. Among 1896 patients, dabigatran 220 and 110 mg showed inferior efficacy to enoxaparin (venous thromboembolism rates of 31% [P = .02 vs enoxaparin], 34% [P < .001 vs enoxaparin], and 25%, respectively). Bleeding rates were similar, and no drug-related hepatic illness was recognized. Dabigatran, effective compared to once-daily enoxaparin, showed inferior efficacy to the twice-daily North American enoxaparin regimen, probably because of the latter's more intense and prolonged dosing.

Is cement still a fixation option for total hip arthroplasty?

Debate remains with regard to the best fixation method for total hip arthroplasty. Much of the argument supporting cementless fixation has been based upon the failure of cement fixation with earlier designs and surgical techniques. There are extensive published data supporting the clinical efficacy and durability of cement fixation. Recent meta-analyses support superior results of cement fixation when compared to cementless fixation in large subsets of patient populations.

Venous Thromboembolism Prophylaxis after Total Knee Arthroplasty.

Venous thromboembolic disease (VTED) is a major cause of morbidity and mortality after total knee arthroplasty (TKA). Current VTED prophylaxis protocols consist of early mobilization, mechanical compression devices, and pharmacologic agents. Venous phasic flow-regulated below-knee devices are generally favored, but the optimal duration and method of mechanical prophylaxis is unknown. Risk stratification models have been developed to guide pharmacologic prophylaxis. For patients with standard VTED risk profile, aspirin has become increasingly popular. Recent studies have validated the efficacy, relatively low bleeding risks, and cost-effectiveness of aspirin in the patients with standard risk profile. Current evidence suggests that the newer oral anticoagulants, including the factor Xa and the direct thrombin inhibitors, are effective for the reduction of postoperative VTED but may be associated with increased bleeding and wound complication rates.

Are critical pathways and implant standardization programs effective in reducing costs in total knee replacement operations?

BACKGROUND: Total knee replacement (TKR) operation is one of the most effective procedures, both clinically and in terms of cost. Because of increased volume and cost for this procedure during the past 3 decades, TKRs are often targeted for cost reduction. The purpose of this study was to evaluate the efficacy of two cost reducing methodologies, establishment of critical clinical pathways, and standardization of implant costs. STUDY DESIGN: Ninety patients (90 knees) were randomly selected from a population undergoing primary TKR during a 2-year period at a tertiary teaching hospital. Patients were assigned to three groups that corresponded to different strategies implemented during the evolution of the joint-replacement program. Medical records were reviewed for type of anesthesia, operative time, length of stay, and any perioperative complications. Financial information for each patient was compared among the three groups. RESULTS: Data analysis demonstrated that the institution of a critical pathway significantly shortened length of hospital stay and was effective in reducing the hospital costs by 18% (p < 0.05). In addition, standardization of surgical techniques under the care of a single surgeon substantially reduced the operative time. Selection of implants from a single vendor did not have any substantial effect in additionally reducing the costs. CONCLUSIONS: Standardized postoperative management protocols and critical clinical pathways can reduce costs and operative time. Future efforts must focus on lowering the costs of the prostheses, particularly with competitive bidding or capitation of prostheses costs. Although a single-vendor approach was not effective in this study, it is possible that a cost reduction could have been realized if more TKRs were performed, because the pricing contract was based on projected volume of TKRs to be done by the hospital.

Venous thromboembolism following total knee replacement.

Venous thromboembolic disease (VTE) remains the most common and potentially fatal complication following total knee replacement (TKR). Its incidence has been reported in excess of 50% if no prophylaxis is used. Even with current prophylaxis regimens, VTE incidence remains high in the range of 25% to 30%. Three prophylaxis regimens are recommended according to the guidelines put forth by the American College of Chest Physicians: 1) low-molecular-weight heparin, 2) indirect factor Xa inhibitor, and 3) adjusted-dose warfarin. Phase II and III clinical trials are currently underway to evaluate the efficacy and safety of newer antithrombotic agents as prophylaxis against VTE following TKR.

Stem geometry changes initial femoral fixation stability of a revised press-fit hip prosthesis: A finite element study.

BACKGROUND: Stable femoral fixation during uncemented total hip arthroplasty is critical to allow for subsequent osseointegration of the prosthesis. Varying stem designs provide surgeons with multiple options to gain femoral fixation. OBJECTIVE: The purpose of this study was to compare the initial fixation stability of cylindrical and tapered stem implants using two different underreaming techniques (press-fit conditions) for revision total hip arthroplasty (THA). METHODS: A finite element femur model was created from three-dimensional computed tomography images simulating a trabecular bone defect commonly observed in revision THA. Two 18-mm generic femoral hip implants were modeled using the same geometry, differing only in that one had a cylindrical stem and the other had a 2 degree tapered stem. Surgery was simulated using a 0.05-mm and 0.01-mm press-fit and tested with a physiologically relevant loading protocol. RESULTS: Mean contact pressure was influenced more by the surgical technique than by the stem geometry. The 0.05-mm press-fit condition resulted in the highest contact pressures for both the cylindrical (27.35 MPa) and tapered (20.99 MPa) stems. Changing the press-fit to 0.01-mm greatly decreased the contact pressure by 79.8% and 78.5% for the cylindrical (5.53 MPa) and tapered (4.52 MPa) models, respectively. The cylindrical stem geometry consistently showed less relative micromotion at all the cross-sections sampled as compared to the tapered stem regardless of press-fit condition. CONCLUSIONS: This finite element analysis study demonstrates that tapered stem results in lower average contact pressure and greater micromotion at the implant-bone interface than a cylindrical stem geometry. More studies are needed to establish how these different stem geometries perform in such non-ideal conditions encountered in revision THA cases where less bone stock is available.

Arthroscopic debridement of acute periprosthetic septic arthritis of the knee.

PURPOSE: To evaluate the efficacy of a treatment protocol including arthroscopic irrigation and debridement in resolving acute periprosthetic septic arthritis of the knee. TYPE OF STUDY: Retrospective review. METHODS: During a 1-year period, patients presenting with acute septic arthritis of the knee after total knee arthroplasty were screened for suitability for treatment with an arthroscopic debridement protocol consisting of (1) arthroscopic debridement and synovectomy with at least 12 L of antibiotic irrigant, (2) suction drainage until minimum output, (3) repeat arthroscopy for fever persisting beyond 48 hours, and (4) intravenous antibiotics for 6 weeks. Only previously well-functioning arthroplasties presenting within 7 days of symptom onset in patients without immunocompromising factors and with radiographically stable prosthetic components were selected for this treatment protocol. Five knees in 4 patients met the inclusion criteria and were examined clinically and radiographically at minimum 36-month follow-up. RESULTS: The mean follow-up interval was 41 months (range, 36 to 43 months). No knee had been revised or had revision planned for infection, although 1 had undergone tibial insert exchange for polyethylene wear. Follow-up radiographs showed no prosthetic loosening, and Knee Society scores averaged 88 (range, 75-95) in the 4 retained knees, 3 of which were subjectively thought to have returned to their preinfection level of functioning. All knees were infected with a single organism not considered highly virulent. No patients required oral suppressive antibiotics for their knees. CONCLUSIONS: Early aggressive arthroscopic debridement as part of a treatment protocol of acute periprosthetic knee septic arthritis with well-fixed and functioning implants can be an effective treatment option in selected cases. LEVEL OF EVIDENCE: Level IV study (no, or historical control group).

Incidence of heterotopic ossification following total hip arthroplasty in patients with prior stroke.

This study reviewed the incidence of heterotopic ossification and the functional limitations in a cohort of consecutive patients with prior stroke who underwent primary total hip arthroplasty (THA). Thirty-one primary THAs were performed in 22 patients who had a cerebrovascular accident prior to THA. Mean follow-up 35 months. The overall incidence of heterotopic ossification was 36%, with significant Brooker class III and IV heterotopic ossification reported in 22% of patients. The data suggest that prior cerebrovascular accident may pose an increased risk of significant heterotopic ossification following primary THA. Consideration of prophylaxis in this subset of patients may be warranted.

New anticoagulants for thromboprophylaxis after total knee arthroplasty.

Total knee arthroplasty (TKA) is one of the most common orthopedic procedures in the United States. The number of TKAs is expected to rise significantly over the next 2 decades. One of the most common complications after TKA is venous thromboembolism (VTE), which is potentially fatal. The incidence of VTE is effectively reduced by prophylactic anticoagulants, and clinical guidelines have been developed to improve VTE management. However, current anticoagulants have limitations in terms of efficacy, safety, half-life, ease of administration, and patient adherence. Moreover, these anticoagulants require routine monitoring and dose adjustment, and potential bleeding complications represent an important concern. A new generation of anticoagulants, including recently approved rivaroxaban, is being developed to address the shortcomings of current agents. The efficacy and safety of these newer agents are comparable with those of existing ones. Rivaroxaban is the only new oral agent that is approved for use in TKA and that has demonstrated an efficacy superior to that of enoxaparin in phase 3 trials. To optimize the management of VTE prophylaxis after TKAs, orthopedic surgeons must have a thorough understanding of these new oral agents.