Friedrich Boettner

Tranexamic acid use and postoperative outcomes in patients undergoing total hip or knee arthroplasty in the United States: retrospective analysis of effectiveness and safety

Objective To determine the effectiveness and safety of perioperative tranexamic acid use in patients undergoing total hip or knee arthroplasty in the United States. Design Retrospective cohort study; multilevel multivariable logistic regression models measured the association between tranexamic acid use in the perioperative period and outcomes. Setting 510 US hospitals from the claims based Premier Perspective database for 2006-12. Participants 872 416 patients who had total hip or knee arthroplasty. Intervention Perioperative intravenous tranexamic acid use by dose categories (none, ≤1000 mg, 2000 mg, and ≥3000 mg). Main outcome measures Allogeneic or autologous transfusion, thromboembolic complications (pulmonary embolism, deep venous thrombosis), acute renal failure, and combined complications (thromboembolic complications, acute renal failure, cerebrovascular events, myocardial infarction, in-hospital mortality). Results While comparable regarding average age and comorbidity index, patients receiving tranexamic acid (versus those who did not) showed lower rates of allogeneic or autologous transfusion (7.7% v 20.1%), thromboembolic complications (0.6% v 0.8%), acute renal failure (1.2% v 1.6%), and combined complications (1.9% v 2.6%); all P<0.01. In the multilevel models, tranexamic acid dose categories (versus no tranexamic acid use) were associated with significantly (P<0.001) decreased odds for allogeneic or autologous blood transfusions (odds ratio 0.31 to 0.38 by dose category) and no significantly increased risk for complications: thromboembolic complications (odds ratio 0.85 to 1.02), acute renal failure (0.70 to 1.11), and combined complications (0.75 to 0.98). Conclusions Tranexamic acid was effective in reducing the need for blood transfusions while not increasing the risk of complications, including thromboembolic events and renal failure. Thus our data provide incremental evidence of the potential effectiveness and safety of tranexamic acid in patients requiring orthopedic surgery.

Total condylar knee arthroplasty: a long-term followup.

Between July 1977 and December 1983, 80 patients underwent 120 arthroplasties using a total condylar knee prostheses. Forty-one patients (68 knees) died and 13 patients were lost to followup. Twenty-six patients with 34 total condylar replacements were available for clinical followup. During the followup, 10 knees in nine patients (8.3%) from the overall 80 patients (120 knees) underwent revision; three (four knees) for aseptic loosening, one for periprosthetic fracture, three for infection, and two patients underwent revision for pain. Three revisions (three patients) occurred in the group of 26 patients available for followup. The average age of this group of patients at followup was 78 years (range, 53–94 years). There were 10 men and 16 women. Considering the high mean age of the patients in the series and patients’ overall health status, the clinical results were extremely good. Kaplan-Meier analysis showed a survivorship of 91% at 23 years followup, considering revision as an end point. Although there have been several changes in total knee replacement designs, materials, and implantation techniques, the long-term outcome of the original total condylar knee prosthesis is excellent.

Revised histopathological consensus classification of joint implant related pathology

This extended classification of joint implant related pathology is a practical histopathologic classification based on defined morphological criteria covering the complete spectrum of pathohistologic changes in periprosthetic tissues. These changes may occur as a consequence of endoprosthetic replacement of large joints and may lead to a reduction in the prosthesis survival rate. We describe the established consensus classification of the periprosthetic membrane, in which aseptic and septic prosthetic loosening can be subdivided into four histological types, as well as histopathological criteria for additional significant pathologies including endoprosthetic-associated arthrofibrosis, particle-induced immunological, inflammatory and toxic mechanisms (adverse reactions), and bone tissue pathologies. These characteristic tissue alterations and their relationships are summarized in the extended classification. Since particle heterogeneity in periprosthetic tissue is high and particle identification is a necessary part of diagnosis, the identification of different types of particles is described in the histopathological particle algorithm. The morphological qualities of prosthetic material particles and the demarcation between abrasion and non-abrasion endogenous particles are also summarized. This feasible classification which is based on low cost standard tissue processing and examination and on well-defined diagnostic criteria is a solid platform for the histological diagnosis of implant associated pathologies providing a stable and reproducible tool for the surgical pathologist. Since this classification is suitable for standardized histopathological diagnostics, it might also provide a useful data set for joint arthroplasty registers, particularly for registers based on so-called routine data.

MRI analysis for rotation of total knee components

PURPOSE The aim of this study was to analyze rotation of total knee (TKA) implant components using magnetic resonance imaging (MRI) and to assess the reproducibility of results. It was hypothesized that rotation of both femoral and tibial implants would be reliably reproduced. METHODS A retrospective analysis of 55 MRI studies in subjects with painful TKA implants was conducted. There were 27 zirconium and 28 cobalt/chrome/molybdenum alloy (CoCrMo) femoral components in the group. The rotation angle of femoral and tibial components was measured and determined. Statistical analysis included tests for reliability, variance between implant groups, standard deviations and confidence intervals. RESULTS There was a sufficient inter- and intra-observer reliability determined for rotation in all implants. The inter-observer reliability was notably higher in the zirconium femur group with significant less variance and lower standard deviations than the CoCrMo femoral component comparison group. Standard deviations for femoral rotational analysis were within a clinically acceptable range. The standard deviations were considerably higher in the tibial component rotational analysis. CONCLUSION MRI analysis of the rotation of femoral implants after TKA allows good reproducibility, especially with review of zirconium implants. There is less reproducibility for tibial components related to the applied geometric method to quantify rotation and not to the MRI technique.

An analysis of the safety of epidural and spinal neuraxial anesthesia in more than 100,000 consecutive major lower extremity joint replacements.

Background and Objectives A feared complication of spinal or epidural anesthesia is the development of epidural or spinal hematoma with subsequent neural element compression. Most available data are derived from the obstetric literature. Little is known about the frequency of hematoma occurrence among patients undergoing orthopedic joint arthroplasty, who are usually elderly and experience significant comorbidities. We sought to study the incidence of clinically significant lesions after spinal and epidural anesthesia and further describe their nature. Methods We retrospectively analyzed a database of all patients who underwent total hip or total knee arthroplasty under neuraxial anesthesia at our institution between January 2000 and October 2010. Patients with radiographically confirmed epidural lesions were identified and further analyzed. Results A total of 100,027 total knee and hip replacements under neuraxial anesthesia were performed at our institution. Ninety-seven patients underwent imaging studies to evaluate perioperative neurologic deficits (0.96/1000; 95% confidence interval, 0.77–1.16/1000). Eight patients were identified with findings of an epidural blood or gas collection (0.07/1000; 95% confidence interval, 0.02–0.13/1000). No patients receiving only spinal anesthesia were affected. All patients diagnosed with hematoma took at least 1 drug that potentially impaired coagulation (5 nonsteroidal anti-inflammatory agents, 1 a tricyclic antidepressant, and 1 an antiplatelet drug). No patient incurred persistent nerve damage. Conclusions The incidence of epidural/spinal complications found in this consecutive case series is relatively low but higher than previously reported in the nonobstetric population. Further research using large data sets could quantify the significance of some of the potentially contributing factors observed in this study.

Matched-pair total knee arthroplasty retrieval analysis: Oxidized zirconium vs. CoCrMo

Oxidized zirconium (OxZr) was introduced to serve as a ceramic surface for femoral components in TKA. The aim of this study was to compare retrieved OxZr components and corresponding PE inserts in matched comparison with conventional cobalt/chrome/molybdenum alloy (CoCrMo). Eleven retrieved posterior stabilized TKA with an OxZr femoral component were included. This included 6 implants from an earlier preliminary study. From a cohort of 56 retrieved TKA with conventional CoCrMo femoral components, pairs were matched according to duration of implantation, patient age, reason for revision, and BMI. Polyethylene inlays and femoral components were optically scored for in vivo damage. The average damage score of the tibial PE inserts was significantly lower with OxZr components (p=0.01). Mainly burnishing and scratches were found. The average wear score in the visual analysis of the femoral components was significantly lower for the OxZr as well (p=0.005). Femoral components made of OxZr were less sensitive to in vivo damage and corresponding PE inlays also showed less damage than CoCrMo components.

MRI analysis of the component-bone interface after TKA

PURPOSE The aim of the study is to describe and characterize the implant-bone interface of femoral, tibial and patellar components after TKA using magnet resonance imaging (MRI). SCOPE Fifty-five patients who underwent MRI modified to reduce artifacts after TKA were identified retrospectively from medical records. This included 27 TKA with a zirconium femoral component and 28 TKA with conventional cobalt/chrome/molybdenum alloy component (CoCrMo). The MRIs were evaluated by two blinded, independent investigators and Cohens Kappa was applied to determine the interobserver reliability. Excellent visibility, interobserver agreement and reliability was found for the interface of the tibial components, patellar buttons, and for femoral components made of zirconium. Conventional CoCrMo components caused significant artifact that interfered with the evaluation of the interface of femoral components. CONCLUSION MRI performed with a special protocol allows good reproducibility of analysis of implant-bone interface at tibia and patella after TKA. The femoral interface was visualized for components made of zirconium. Conventional CoCrMo femoral components caused considerable artifact and interfered with the evaluation of the femoral interface. MRI tailored to reduce metallic susceptibility artifact can be a helpful tool for evaluation of prosthesis bone interface and may be helpful for the diagnosis of component loosening.

The value of valgus stress radiographs in the workup for medial unicompartmental arthritis.

BackgroundHigh tibial osteotomy and unicompartmental knee arthroplasty are surgical treatment options for unicompartmental knee arthritis; these procedures are indicated for patients who do not have severe arthritis in the lateral compartment. Valgus stress radiographs sometimes are used to make this evaluation, but this test has not been critically evaluated.Questions/purposesWe sought to determine (1) whether valgus stress radiographs help to evaluate the integrity of the cartilage in the lateral compartment in patients undergoing TKA for noninflammatory arthritis, and (2) whether valgus stress radiographs can identify patients whose varus deformity is correctable.MethodsWe reviewed preoperative hip-to-ankle standing radiographs, AP standing radiographs, and valgus stress radiographs of 84 patients (91 knees) who underwent TKA for varus knee arthritis between July 2010 and January 2012. Valgus stress radiographs were obtained with the patient supine with the knee 20° flexed and a firm manual valgus force was applied through the knee. On valgus stress radiographs, the lateral compartment joint space width and the corrected mechanical alignment were measured. Intraoperative cartilage assessment (Outerbridge grade) was compared with lateral compartment joint space width. Knees with mechanical leg alignment of 3° varus to 3° valgus on valgus stress radiographs were considered correctable deformities.ResultsThe lateral compartment joint space width on valgus stress radiographs did not correlate with the intraoperative Outerbridge grading of the lateral compartment cartilage (rs = −0.154; p = 0.146). The majority of knees (93%; 55 of 59) with 10° or less mechanical varus on hip-to-ankle standing radiographs were correctable within the range of 3° varus to 3° valgus.ConclusionsValgus stress radiographs provided no added benefit to the radiographic assessment of the lateral compartment cartilage and regarding the correctability of the varus deformity.Level of EvidenceLevel III, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.

Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling.

Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal‐on‐metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion‐related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri‐implant osteolysis. In this study, we characterize tribocorrosion‐associated ALTR at a molecular level. Gene expression profiling of peri‐implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP‐10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT‐1). Importantly, MIG/CXCL9 and IP‐10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at‐risk patients.

Varus gonarthrosis predisposes to varus malalignment in TKA.

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.