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As perioperative protocols have improved, there has been a reduction in the rates of key complications after hip and knee arthroplasty. Likewise, as we have been able to make patients more comfortable postoperatively, hospital length of stay has decreased and in some centers, hip and knee arthroplasty is now routinely performed as an outpatient. While the number of surgeons offering this option and patients choosing to have procedures performed as an outpatient grows, many questions revolve around this movement. This article will review the data supporting outpatient arthroplasty, the business and legal aspects involved, if surgeons can align with their hospital to offer these services, and how tightly knit and highly organized teams are key to the success of safely offering hip and knee arthroplasty on an outpatient basis. [ABSTRACT FROM AUTHOR]

Background: Metaphyseal bone loss is commonly encountered in revision total knee arthroplasty (TKA). Anderson Orthopaedic Research Institute types 2 and 3 defects generally require some form of metaphyseal fixation or augmentation. This study evaluates the midterm results of stepped, porous-coated metaphyseal sleeves in revision TKA in the setting of severe bone loss.Methods: Patients who underwent revision TKA using metaphyseal sleeves from March 2006 to May 2014 at our institution were identified from a prospective research database. Preoperative patient characteristics and operative data were reviewed. Postoperative outcomes were compared with preoperative values. Primary study outcomes included complications, reoperations, radiographic assessment of sleeve osteointegration, and survivorship.Results: One hundred sixteen knees (108 patients) underwent revision TKA with 152 metaphyseal sleeves (111 tibial and 41 femoral). Anderson Orthopaedic Research Institute defect classification included 5 type 2A, 89 type 2B, and 17 type 3 tibial defects; and 3 type 2A, 34 type 2B, and 4 type 3 femoral defects. There were 3 intraoperative fractures (1.9%) associated with sleeve preparation and/or insertion. Six knees (5 patients) were lost to follow-up and 5 patients (6 knees) died before 2 years. Of the remaining 104 knees (98 patients, 134 sleeves), mean follow-up was 5.3 years (range 2-9.6 years). Nineteen knees (16.4%) required reoperation, most commonly for recurrent infection. Only one sleeve demonstrated radiographic evidence of failed osteointegration, but did not require revision. Two sleeves (1.5%) required removal and/or resection for recurrent infection.Conclusion: This large retrospective series illustrates the utility of porous metaphyseal sleeves in revision TKA with a low rate of intraoperative complications, excellent osteointegration, and long-term fixation. [ABSTRACT FROM AUTHOR]

Background: Malalignment of the lower extremity is commonly seen in patients with severe osteoarthritis undergoing total knee arthroplasty (TKA) and is believed to play a role in quadriceps strength loss. Deformity correction is typically achieved through surgical techniques to provide appropriate ligamentous balancing. Therefore, this study examined the influence of change in lower extremity alignment on quadriceps strength outcomes after TKA.Methods: Seventy-three participants (36 male; mean age, 62 years; and mean body mass index, 29.7 kg/m2) undergoing primary unilateral TKA were used in this investigation. Before surgery and at 1 and 6 months after surgery, measures of isometric knee extensor strength, quadriceps activation, and long-standing plain films were collected. Using the films, measures of mechanical axis, distal femoral angle (DFA), proximal tibial angle, and patellofemoral angle were performed. Hierarchical linear regression was used to evaluate how change in alignment from baseline to 1 and 6 months influenced the change in quadriceps strength.Results: DFA was found to significantly contribute to changes in quadriceps strength at 1 and 6 months after TKA above those contributed by associated covariates. None of the other measures of lower extremity alignment were found to contribute to quadriceps strength in this sample.Conclusion: Reductions in quadriceps strength experienced after TKA are likely to be influenced by changes in lower extremity alignment. Specifically, measures of DFA were found to significantly contribute to these changes. Future work is needed to prospectively examine measures of lower extremity alignment change and recovery after TKA. [ABSTRACT FROM AUTHOR]

Background: Constrained implants are frequently required in revision total knee arthroplasty (TKA) and are associated with an increase in aseptic component loosening and damage or wear to the constraining mechanisms, compared with primary TKA. The purpose of the following study was to evaluate the midterm clinical and radiographic results including the incidence of bearing complications in a group of patients undergoing revision TKA using mobile-bearing revision TKA implants.Methods: We retrospectively reviewed 316 consecutive mobile-bearing revision TKAs performed at 2 centers between 2006 and 2010. There were 183 women and 133 men with a mean age of 66 years. The patients were evaluated clinically using the Knee Society scores. A radiographic analysis was performed. Bearing specific complications (ie, instability or dislocation) were recorded.Results: Patients were followed-up for a minimum of 24 months and a median of 59.88 months (range 24-121.2). The average Knee Society knee score and function scores increased from 40.8 and 47.9 points preoperatively to 80 points and 70.3 points, respectively (P < .01). The average knee flexion improved from 105.6° preoperatively to 117.4° postoperatively (P < .01). Eight patients required subsequent implant revision. No cases of bearing complications were observed.Conclusion: Revision TKA using mobile-bearing revision components demonstrated favorable midterm clinical and radiographic results with no occurrence of bearing instability or dislocation. Longer follow-up is required to evaluate for potential advantages of mobile-bearings over fixed-bearing revision components in terms of polyethylene wear reduction, reduced stress transmission across fixation interfaces, and reduced stress on the polyethylene post. [ABSTRACT FROM AUTHOR]

Background: Stress shielding is a well-recognized complication associated with total knee arthroplasty. However, this phenomenon has not been thoroughly described. Specifically, no study to our knowledge has evaluated the radiographic impact of utilizing various tibial component compositions on tibial stress shielding.Methods: We retrospectively reviewed 3 cohorts of 50 patients that had a preoperative varus deformity and were implanted with a titanium, cobalt chromium (CoCr), or an all polyethylene tibial implant. A radiographic comparative analysis was performed to evaluate the amount of medial tibial bone loss in each cohort. In addition, a clinical outcomes analysis was performed on the 3 cohorts.Results: The CoCr was noted to have a statistically significant increase in medial tibial bone loss compared with the other 2 cohorts. The all polyethylene cohort had a statistically significantly higher final Knee Society Score and was associated with the least amount of stress shielding.Conclusion: The CoCr tray is the most rigid of 3 implants that were compared in this study. Interestingly, this cohort had the highest amount of medial tibial bone loss. In addition, 1 patient in the CoCr cohort had medial soft tissue irritation which was attributed to a prominent medial tibial tray which required revision surgery to mitigate the symptoms. [ABSTRACT FROM AUTHOR]

Background: Because of improvements in ceramic materials and manufacturing, the incidence of ceramic failures has decreased over time. Recent concerns with corrosion have contributed to an increase in ceramic ball head utilization. The purpose of this study is to report the incidence of modern alumina bearing failures from a single major ceramic manufacturer in nearly 6 million hip implants and to identify trends in the modes of failure of these implants.Methods: Beginning in the year 2000, CeramTec AG (Plochingen, Germany) began a comprehensive program for reporting and gathering failure data on its products. From January 1, 2000, to December 31, 2013, over 3.2 million pure alumina (PA) and 2.78 million alumina matrix composite (AMC) ceramic ball heads were implanted worldwide. During this period, there were 672 PA and 28 AMC femoral head fractures. The fractures were analyzed with respect to time to failure, head size, and implant factors.Results: The incidence of clinical fractures of modern PA femoral heads and AMC femoral heads was 1 in 5000 (0.0201%) and 1 in 100,000 (0.0010%), respectively (P < .0001). The majority of implant failures (80%) occurred within 48 months following surgery (P < .01). Fractures were usually associated with specific events such as trauma, mismatched components, and dislocations. Large-diameter PA heads were associated with a lower rate of fracture compared to smaller-diameter femoral heads (0.0316% for 28-mm heads vs 0.0080% for heads 32 mm or greater [P < .01]). Similar trends were observed with AMC heads. The neck lengths of the femoral ball heads were also a factor: a short-taper 28-mm ball head was more likely to fracture compared to other neck lengths (P < .01).Conclusion: Modern PA ceramic heads are reliable with extremely low risk of fracture. The reliability is even better with AMC heads. [ABSTRACT FROM AUTHOR]

Background: Stress shielding is an uncommon complication associated with primary total knee arthroplasty. Patients are frequently identified radiographically with minimal clinical symptoms. Very few studies have evaluated risk factors for postoperative medial tibial bone loss. We hypothesized that thicker cobalt-chromium tibial trays are associated with increased bone loss.Methods: We performed a retrospective review of 100 posterior stabilized, fixed-bearing total knee arthroplasty where 50 patients had a 4-mm-thick tibial tray (thick tray cohort) and 50 patients had a 2.7-mm-thick tibial tray (thin tray cohort). A clinical evaluation and a radiographic assessment of medial tibial bone loss were performed on both cohorts at a minimum of 2 years postoperatively.Results: Mean medial tibial bone loss was significantly higher in the thick tray cohort (1.07 vs 0.16 mm; P = .0001). In addition, there were significantly more patients with medial tibial bone loss in the thick tray group compared with the thin tray group (44% vs 10%, P = .0002). Despite these differences, there were no statistically significant differences in range of motion, knee society score, complications, or revision surgeries performed.Conclusion: A thicker cobalt-chromium tray was associated with significantly more medial tibial bone loss. Despite these radiographic findings, we found no discernable differences in clinical outcomes in our patient cohort. Further study and longer follow-up are needed to understand the effects and clinical significance of medial tibial bone loss. [ABSTRACT FROM AUTHOR]

Background: Use of leukocyte esterase (LE) testing of synovial fluid as an adjunct to the infection workup in total joint arthroplasty patients has been advocated. The purpose of this study was to determine the false positive rate of this test.Methods: Two hundred patients with the diagnosis of degenerative osteoarthritis undergoing a total knee arthroplasty were identified for this study. The knee joint was aspirated under sterile conditions before performing the total knee arthroplasty. The fluid was analyzed with an LE reagent strip.Results: There were 27 bloody and 17 dry aspirations. One hundred forty-nine patients produced an aspiration that allowed for LE testing. There was 1 positive LE result. The specificity of the LE test was found to be 99.3%.Conclusion: These data suggest the LE strip as a part of the workup for infection in a native knee should yield few false positive results. [ABSTRACT FROM AUTHOR]

Abstract: Sequential bilateral total knee arthroplasty performed on 54 patients utilizing navigation (CAS-TKA) in one knee and traditional instrumentation (T-TKA) in the contralateral knee was reviewed at a mean follow-up duration of 2.5years. There were no differences with regard to KSS, ROM, postoperative anatomic alignment, mechanical axis, or tibial angle. There was a statistically significant decrease in outliers for the CAS-TKA group with respect to anatomic alignment (3.7% vs. 17.0%, P =0.024), mechanical axis (6.1 vs. 20.4%, P =0.037) and tibial component alignment (0% vs. 7.5%, P =0.042). There is no apparent benefit of CAS-TKA with regards to KSS, ROM, or alignment in the hands of fellowship-trained total joint specialists. The clinical relevance of reduced outliers in the CAS-TKA group is unknown with the current follow-up interval. [Copyright &y& Elsevier]

Abstract: An extensive database search was completed to perform a meta-analysis of outcomes of mobile-bearing total knee arthroplasty. Nineteen manuscripts encompassing 3506 total knee arthroplasty met criteria for analysis (average follow-up, 8.6 years). Data were subdivided based on design type and included rotating platform, meniscal bearing, and anterior-posterior glide-rotation subgroups. Fifteen-year survivorship of rotating platform designs (96.4%) was greater than meniscal bearing implants (86.5%). Mean component loosening (0.33%) and bearing instability (<1%) for all subgroups were uncommon. Implants placed prior to 1995 exhibited higher rates of bearing complications (1.6% vs 0.1%). Excellent results were obtained with mobile-bearing TKA over 2 decades. Loosening and bearing instability were uncommon. Bearing complications lessened after 1995, possibly secondary to improved surgical technique. [Copyright &y& Elsevier]

Abstract: Although metal-on-metal total hip arthroplasty (MOM THA) has been used for over 3 decades, substantial improvements in manufacturing and design have led to improved durability with modern implants. Reported advantages of the use of MOM THA include very low wear and subsequent osteolysis, increased range of motion to impingement secondary to the availability of larger diameter femoral heads, and the potential to monitor implant performance by serial assessment of metal ion levels. Clinical results of both first-generation and second-generation MOM THA have revealed good survivorship and a low incidence of osteolysis. Although the advantages of low wear and increased range of motion have made MOM THA an attractive bearing surface option, more widespread use of MOM bearing surfaces has been tempered with concern for increased metal ion levels and hypersensitivity reactions. [Copyright &y& Elsevier]

Background Some patients perceive symptomatic improvement in the contralateral knee after unilateral total knee arthroplasty (TKA). This so-called “splinting effect” has been observed but has not been radiographically evaluated. Methods A retrospective review of patients with bilateral knee osteoarthritis treated with unilateral TKA was performed. Patients were subcategorized into 2 groups based on whether contralateral TKA was performed within the 2-year period. Contralateral radiographic measurements were performed. Results Forty-four of 203 patients had contralateral TKA performed within 2 years. Preoperative parameters were significantly worse in the bilateral group. By 6 weeks postoperatively, mechanical axis plumbline improved approximately 1°, with more change in those patients with preoperative varus alignment. Larger delta changes were also present in bilateral group preoperative to 1-year radiographs for tibiofemoral angle and joint space widening. Conclusion In patients with bilateral knee osteoarthritis who undergo unilateral TKA, a splinting effect may be present and measurable radiographically with improvement of contralateral mechanical axis plumbline. Further research is necessary to determine whether this improvement may delay contralateral TKA implantation. [ABSTRACT FROM AUTHOR]