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Trunnionosis is emerging as an early mode of failure in conventional metal-on-polyethylene total hip arthroplasty. It is defined as wear or corrosion at the trunnion, the taper at the femoral head-neck interface. Trunnion wear can result in a variety of negative sequelae and, in severe cases, necessitate revision arthroplasty. We describe a 64-year-old man with a metal-on-polyethylene total hip arthroplasty who presented with a sensation of clunking in the hip. Initial imaging and laboratory studies were inconclusive, and the decision was made to monitor. Two years later, trunnion wear was detected on radiographs, presenting as an abnormal alignment of the femoral neck relative to the femoral head. Several case reports and series describe catastrophic total hip arthroplasty failure due to trunnionosis. However, few describe the radiographic signs of wear at the trunnion before gross failure. This early presentation is important to recognize to minimize patient morbidity and aid surgical planning.

Background In January 2018, the Center for Medicare and Medicaid Services (CMS) removed total knee arthroplasty (TKA) from the inpatient-only list. This impacted hospital reimbursement, Comprehensive Joint Replacement (CJR) bundle volumes, and bundle performance. We describe these impacts at an academic teaching hospital. Methods We reviewed CJR bundle data provided by CMS and internal databases to identify the shift in CJR TKA episode volume since January 2018, the impact on postacute care (PAC) utilization rates and readmissions, financial impact to the bundle, and impact on hospital reimbursement. We used data provided to CJR participants, internal hospital sources, and the Medicare Limited Data Set. Results Between 2017 and 2018, CJR TKA episodes decreased from 91 to 51 (44% reduction). Inpatient PAC utilization was significantly higher in 2018 (20% vs 8%). The 90-day readmission rates increased from 5.5% to 12.7%. Average variance to target dropped from 15% to 5%. Average CMS reimbursement for TKA at our institution in 2019 was $14,823 for inpatients and $9299 for outpatients. We experienced $930,463 in decreased reimbursement from January 2018 to September 2019 as a result of the shift from inpatient to outpatient. In addition, we expect $625,143 in decreased incentive payments as higher functioning and lower cost outpatient TKAs are excluded from CJR. Conclusion Although CMS projected a minimal impact on CJR bundle participants, this has not been the case at our institution. We experienced reduced volumes, increased PAC utilization, and a substantial financial impact. We expect a similar outcome when CMS removes total hip arthroplasty from the inpatient-only list.

Background Osteoarthritis is a mechanical abnormality characterized by chronic joint pain associated with degeneration of the articular cartilage, synovitis, and local inflammation, leading to loss of function and pain. A connection exists between the peripheral nervous system and inflammatory joint degeneration. The process by which inflammation is influenced by the nervous system is known as neuroinflammation. One of the neuropeptides involved in peripheral neuroinflammation is nociceptin, a peptide related to the opioid class of substances. Nociceptin has both pro- and anti-inflammatory effects. Some studies show that nociceptin can be measured in synovial fluid, while other studies have not been able to detect it. The presence of nociceptin in synovial fluid could imply a molecular role for the neuropeptide in the joint, both physiologically as well as pathophysiologically. The goal of this pilot study was to determine whether nociceptin was present in the synovial fluid of osteoarthritic knees. Methods Patients undergoing primary total knee arthroplasty were enrolled after Institutional Review Board approval was obtained. Synovial fluid was aspirated from patients’ operative knee joints and blood samples were obtained. A commercially available enzyme Immunoassay kit was used to test for nociceptin. A linear mixed-effects model was developed to account for the repeated measurements and baseline covariates. Least squares (adjusted) means were derived from the model to compare the sample types and to compare subgroups. Results Twenty patients were included in this study. Nociceptin was detected in the synovial fluid and plasma of all patients. The mean concentration (± standard deviation) of nociceptin in synovial fluid was 28.7 ± 18.2 pg/ml. The mean concentration of nociceptin in plasma was 45.2 ± 24.3 pg/ml pre-procedure, and 40.1 ± 20.6 pg/ml post-tourniquet deflation. The nociceptin concentration in synovial fluid was significantly lower than the nociceptin concentration in plasma, both pre-procedure and post-tourniquet deflation (p = 0.002 and p = 0.016 respectively). The nociceptin concentration in both plasma and synovial fluid was significantly lower in females versus males (p = 0.012). Conclusion We demonstrated that nociceptin is present in synovial fluid and plasma of patients undergoing total knee arthroplasty. This implies a potential role for nociceptin in modulating inflammation in osteoarthritis. Trial registration ClinicalTrials.gov, NCT02528916. Retrospectively registered on August 19, 2015

Background Total knee arthroplasty (TKA) is commonly performed with proprietary, manual instrumentation provided by the surgical implant manufacturer. Registry studies and meta-analysis, with few outliers, have consistently shown similar functional outcomes and implant survival after TKA regardless of implant manufacturer, implant design, or surgical technique. We hypothesized that process mapping could identify areas for improvement in TKA instrumentation. Methods Seventeen TKA implant systems from 10 companies representing over 90% of all TKAs performed in the United States were evaluated. Instrumentation required for femoral, tibial, and patellar preparation was compared. The number of steps including surgical technician assembly steps, instrument handoffs, and surgeon steps were tabulated based off application of a standardized surgical flow, adjusted for manufacturer-recommended steps during completion of a TKA operation. Results Cruciate-retaining (CR) knee instrumentation in studied systems required 158-225 discrete steps and posterior-stabilized (PS) knees required 181-230 steps. With the fewest steps for femoral, tibial, and patellar instrumentation, CR and PS knee systems could be improved to 145 and 163 steps, respectively. The Arthrex iBalance and the Biomet Vanguard Microplasty required fewest steps among CR systems; the OrthoDevelopment Balanced and the Corin Unity required fewest steps among PS systems. Conclusions Process mapping identified potential areas for improved instrumentation in all studied systems, suggesting the possibility to reduce operative steps broadly across the TKA industry. Patient outcomes were not evaluated by system. Future implant system design changes may do well to reduce unnecessary steps and instrumentation.

Background Acute and acute hematogenous prosthetic joint infections (PJIs) are often treated with open debridement and polyethylene exchange (ODPE) in an effort to save the prosthesis, decrease morbidity, and reduce costs. However, failure of ODPE may compromise a subsequent 2-stage treatment. The purpose of this study is to identify patient factors that impact the success of ODPE for acute and acute hematogenous PJIs. Methods A retrospective review examined comorbidities, preoperative laboratory values, and patient history for patients with successful and failed ODPE treatment for acute perioperative or acute hematogenous periprosthetic hip or knee joint infections. Successful treatment was defined as retaining a well-fixed implant without the need for additional surgery for a minimum of 6-month follow-up with or without lifelong oral maintenance antibiotics. Results Fifty-three of 72 patients (73.6%) underwent successful ODPE. Of the 19 failures, 14 completed 2-stage revision with one subsequent known failure for recurrent infection. Patients with a Staphylococcus aureus infection were more likely to fail ODPE (48.3% vs 11.6%, P = .0012, odds ratio 7.1, 95% confidence interval 2.3-25.3). Patients with a preoperative hematocrit ≤32.1 were also more likely to fail ODPE (55% vs 16%, P = .0013, odds ratio 6.7, 95% confidence interval 2.2-22.4). When neither risk factor was present, 97.1% of PJIs were successfully treated with ODPE. Conclusion S aureus infection and preoperative hematocrit ≤32.1 are independent risk factors for ODPE failure. ODPE is a safe alternative to 2-stage revision in patients without preoperative anemia and without S aureus infection. Two-thirds of patients with a failed ODPE were successfully treated with a 2-stage reimplantation.

Background Centers for Medicare and Medicaid Services removed total knee arthroplasties (TKAs) from the Inpatient-Only list on January 1, 2018, which meant TKAs could be performed on a hospital outpatient basis. We sought to understand (1) what the financial implications have been for hospitals, (2) to what extent financial incentives have influenced the adoption of outpatient TKAs across hospitals, (3) whether adoption of outpatient TKAs has impacted the success of hospitals with managing post-acute care (PAC) spend, and (4) the financial implications to Medicare of the adoption of outpatient TKAs. Methods We used national patient-level Medicare fee-for-service Part A claims data (100% sample) from January 2018 through June 2019 to calculate the inpatient and outpatient TKA payment rate for each hospital, and the distribution in these payments across the country. We then ran case-level regressions to understand the factors associated with adoption of outpatient TKAs, and the drivers of PAC spend. Finally, we quantified the savings to Medicare. Results Hospitals on average received $3682 (30%) lower payment from Medicare for outpatient TKA cases, but this varied widely across hospitals. The difference in payment rates across hospitals was not statistically significantly related to their adoption rate of outpatient TKAs. PAC spend was higher for same-day discharges, but lower for cases that stayed at least 1 night. Based on the adoption rate of outpatient TKAs in Q2 2019, Medicare saved $355M on a run rate basis. Conclusion Hospitals have adopted outpatient TKAs independent of the financial impact. Medicare has benefited from lower PAC spend and lower payments to hospitals.

Introduction:In 2014, we implemented a geriatric hip fracture patient care pathway at our institution which was designed to improve outcomes and decrease time to surgery.Materials and Methods:We analyzed retrospective data from 463 patients, aged greater than 50, who had surgical treatment for a closed hip fracture due to a low-energy injury between 2013 and 2016 at an academic institution. Objective outcome measures included time to surgery, mortality rate, and total hospital length of stay. Our primary goal was to decrease the time to surgery for definitive fracture fixation to within 24 hours of admission to the hospital for patients who were medically fit for surgery.Results:We implemented a multidisciplinary, collaborative approach to address the needs of this specific patient population. Prior to implementing the pathway in 2013, our baseline time to surgery within 24 hours was 74.67%. After implementation, we had incremental yearly increases in the percentage of patients operated on within 24 hours, 82.31% in 2014 ( P = .10) and 84.14% in 2015 ( P = .04). During the study period, our overall time to surgery was reduced by 27% with an initial average of 20.22 hours in 2013, decreasing to 15.33 hours in 2014, and 14.63 hours in 2015. Our mortality rate at 1 year was 16% in 2013, 17% in 2014, and 15% in 2015.Conclusion:With implementation of the pathway, we were able to expedite surgical care for our patients and demonstrate a 10% improvement in the percentage of patients able to have surgery within 24 hours over a 3-year period. Our mortality and hospital length of stay, however, remained the same. Through this collaborative process and system standardization, we believe we have significantly improved not only direct patient care but their overall hospital experience. We continue to make improvements in our pathway.

The continued presence of biofilm may be one cause of the high risk of failure observed with irrigation and debridement with component retention in acute periprosthetic joint infection (PJI). There is a poor understanding of the role of biofilm antibiotic tolerance in PJI. (1) Do increasing doses of cefazolin result in decreased viable biofilm mass on arthroplasty materials? (2) Is cefazolin resistance phenotypic or genotypic? (3) Is biofilm viability a function of biofilm depth after treatment with cefazolin? (4) Is the toxin-antitoxin system, yoeB expression, associated with antibiotic stress? Methicillin-sensitive Staphylococcus aureus biofilm was cultured on total knee arthroplasty (TKA) materials and exposed to increasing doses of cefazolin (control, 0.5, 1.0, 10.0, 100.0 μg/mL). Quantitative confocal microscopy and quantitative culture were used to measure viable biofilm cell density. To determine if cefazolin resistance was phenotypic or genotypic, we measured minimum inhibitory concentration (MIC) after exposure to different cefazolin concentrations; changes in MIC would suggest genotypic features, whereas unchanged MIC would suggest phenotypic behavior. Finally, quantitative reverse transcription-polymerase chain reaction was used to quantify expression of yoeB levels between biofilm and planktonic bacteria after exposure to 1 μg/mL cefazolin for 3 hours. Although live biofilm mass was reduced by exposure to cefazolin when compared with biofilm mass in controls (39.2 × 103 ± 26.4 × 103 pixels), where the level after 0.5 µg/mL exposure also showed reduced mass (20.3 × 103 ± 11.9 × 103 pixels), no further reduction was seen after higher doses (mass at 1.0 µg/mL: 5.0 × 103 pixels ± 1.1 × 103 pixels; at 10.0 µg/mL: 6.4 × 103 ± 9.6 × 103 pixels; at 100.0 µg/mL: 6.4 × 103 ± 3.9 × 103). At the highest concentration tested (100 µg/mL), residual viable biofilm was present on all three materials, and there were no differences in percent biofilm survival among cobalt-chromium (18.5% ± 15.1%), polymethylmethacrylate (22.8% ± 20.2%), and polyethylene (14.7% ± 10.4%). We found that tolerance was a phenotypic phenomenon, because increasing cefazolin exposure did not result in changes in MIC as compared with controls (MIC in controls: 0.13 ± 0.02; at 0.5 µg/mL: 0.13 ± 0.001, p = 0.96; at 1.0 µg/m: 0.14 ± 0.04, p = 0.95; at 10.0 µg/m: 0.11 ± 0.016, p = 0.47; at 100.0 µg/m: 0.94 ± 0.047, p = 0.47). Expression of yoeB after 1 µg/mL cefazolin for 3 hours in biofilm cells was greater in biofilm but not in planktonic cells (biofilm: 62.3-fold change, planktonic cells: −78.8-fold change, p < 0.001). Antibiotics are inadequate at complete removal of the biofilm from the surface of TKA materials. Results suggest that bacterial persisters are responsible for this phenotypic behavior allowing biofilm high tolerance to antibiotics. Antibiotic-tolerant biofilm suggests a mechanism behind the poor results in irrigation and debridement for acute TKA PJI.

Background Higher body mass index (BMI) has been associated with postoperative complications in total knee arthroplasty (TKA) and total hip arthroplasty (THA). However, the association of incremental increases of BMI and its effects on postoperative complications has not been well studied. We hypothesize that there is a BMI cutoff at which there is a significant increase of the risk of postoperative complications. Methods We studied the American College of Surgeons National Surgical Quality Improvement Program from 2006 to 2013. The final cohort included 77,785 primary TKA and 49,475 primary THA subjects, respectively. Patients were separated into 7 groups based on BMI (18.5-24.9 kg/m 2 , 25.0-29.9 kg/m 2 , 30.0-34.9 kg/m 2 , 35.0-39.9 kg/m 2 , 40.0-44.9 kg/m 2 , 45.0-49.9 kg/m 2 , and >50.0 kg/m 2 ). We analyzed data on five 30-day composite complication variables, including any complication, major complication, wound infection, systemic infection, and cardiac and/or pulmonary complication. Results The odds ratio for 4 (any complication, major complication, wound infection, and systemic infection) of 5 composite complications started to increase exponentially once BMI reached 45.0 kg/m 2 or higher in TKA. Similarly, the odds ratio in 3 (any complication, systemic infection, and wound infection) of 5 composite complications showed similar trends in THA patients. These findings were further confirmed with propensity score matching and entropy balancing. Conclusions Our study suggested that there was a positive correlation between BMI and incidences of 30-day postoperative complications in both TKA and THA. The odds of complications increased dramatically once BMI reached 45.0 kg/m 2 .

Background Patient-reported outcomes are essential to demonstrate the value of hip and knee arthroplasty, a common target for payment reforms. We compare patient-reported global and condition-specific outcomes after hip and knee arthroplasty based on hospital participation in Medicare’s bundled payment programs. Methods We performed a prospective observational study using the Comparative Effectiveness of Pulmonary Embolism Prevention after Hip and Knee Replacement trial. Differences in patient-reported outcomes through 6 months were compared between bundle and nonbundle hospitals using mixed-effects regression, controlling for baseline patient characteristics. Outcomes were the brief Knee Injury and Osteoarthritis Outcomes Score or the brief Hip Disability and Osteoarthritis Outcomes Score, the Patient-Reported Outcomes Measurement Information System Physical Health Score, and the Numeric Pain Rating Scale, measures of joint function, overall health, and pain, respectively. Results Relative to nonbundled hospitals, arthroplasty patients at bundled hospitals had slightly lower improvement in Knee Injury and Osteoarthritis Outcomes Score (−1.8 point relative difference at 6 months; 95% confidence interval −3.2 to −0.4; P = .011) and Hip Disability and Osteoarthritis Outcomes Score (−2.3 point relative difference at 6 months; 95% confidence interval −4.0 to −0.5; P = .010). However, these effects were small, and the proportions of patients who achieved a minimum clinically important difference were similar. Preoperative to postoperative change in the Patient-Reported Outcomes Measurement Information System Physical Health Score and Numeric Pain Rating Scale demonstrated a similar pattern of slightly worse outcomes at bundled hospitals with similar rates of achieving a minimum clinically important difference. Conclusions Patients receiving care at hospitals participating in Medicare’s bundled payment programs do not have meaningfully worse improvements in patient-reported measures of function, health, or pain after hip or knee arthroplasty.

Treatment in periprosthetic joint infection (PJI) remains challenging. The failure rate of two-stage revision and irrigation and debridement with component retention in PJI suggests that biofilm cells have a high tolerance to antibiotic chemotherapy. Previous work has demonstrated that biofilm cells have high antibiotic tolerance in vitro, but there is little clinical evidence to support these observations. The aim of this study was to determine if retrieved antibiotic spacers from two-stage revision total knee arthroplasty for PJI have evidence of remaining viable bacteria. Antibiotic poly (methyl methacrylate) (PMMA) spacers from two-stage revision total knee arthroplasty for PJI were prospectively collected and analyzed for bacterial 16s rRNA using polymerase chain reaction (PCR), reverse transcription (RT)-PCR, quantitative RT-PCR (qRT-PCR), and single genome analysis (SGA). PCR and RT-PCR identified bacterial species on 53.8% (7/13) of these samples. When initial culture negative cases are excluded, 68% (6/9) samples were identified with bacterial species. A more rigorous qRT-PCR analysis showed a strong positive signal for bacterial contamination in 30.7% (4/13) of cases. These patients did not show any clinical evidence of PJI recurrence after 15 months of follow-up. Because the half-life of bacterial rRNA is approximately a few days, the identification of bacteria rRNA on antibiotic PMMA spacers suggests that viable bacteria were present after conclusion of antibiotic therapy. This study provides evidence for the high tolerance of biofilm cells to antibiotics in vivo and the important role of bacterial persisters in PJI. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:452-458, 2018.

FDA's Unique Device Identification (UDI) Rule will mandate manufacturers to assign unique identifiers to their marketed devices. UDI use is expected to improve implant documentation and identification. A 2012 American Association of Hip and Knee Surgeons membership survey explored revision total hip and knee arthroplasty implant identification processes. 87% of surgeons reported regularly using at least 3 methods to identify failed implants pre-operatively. Median surgeon identification time was 20 min; median staff time was 30 min. 10% of implants could not be identified pre-operatively. 2% could not be identified intra-operatively. UDI in TJA registry and UDI in EMR were indicated practices to best support implant identification and save time. FDA's UDI rule sets the foundation for UDI use in patient care settings as standard practice for implant documentation.

This article was updated on May 4, 2016, because of a previous error. On page 689, under the “DELAY TKA” heading, the text had previously read “Moderate evidence supports that a 5-month delay to total knee arthroplasty (TKA) does not worsen outcomes.” The text now reads “Moderate evidence supports that an 8-month delay to total knee arthroplasty (TKA) does not worsen outcomes.” An erratum has been published: J Bone Joint Surg Am. 2016 June 15;98(12):e53. The AAOS Evidence-Based Guideline on Surgical Management of Osteoarthritis of the Knee includes both diagnosis and treatment. This clinical practice guideline has been endorsed by the Arthroscopy Association of North America (AANA) and the Society of Military Orthopaedic Surgeons (SOMOS). This brief summary of the AAOS Clinical Practice Guideline contains a list of the recommendations and the rating of strength based on the quality of the supporting evidence. Discussion of how each recommendation was developed and the complete evidence report are contained in the full guideline at http://www.aaos.org/Quality/Clinical\_Practice\_Guidelines/Clinical\_Practice\_Guidelines/. ### BMI AS A RISK FACTOR Strong evidence supports that obese patients have less improvement in outcomes with total knee arthroplasty (TKA). Strength of Recommendation: Strong ★★★★ ### DIABETES AS A RISK FACTOR Moderate evidence supports that patients with diabetes are at higher risk for complications with total knee arthroplasty (TKA). Strength of Recommendation: Moderate ★★★☆ ### CHRONIC PAIN AS A RISK FACTOR Moderate evidence supports that patients with select chronic pain conditions have less improvement in patient reported outcomes with TKA. Strength of Recommendation: Moderate ★★★☆ ### DEPRESSION/ANXIETY AS A RISK FACTOR Limited evidence supports that patients with depression and/or anxiety symptoms have less improvement in patient reported outcomes with total knee arthroplasty (TKA). Strength of Recommendation: Limited ★★☆☆ ### CIRRHOSIS/HEPATITIS C AS A RISK FACTOR Limited evidence supports that patients with cirrhosis …

The outcomes of 18 primary or revision total hip (THA) and knee arthroplasties (TKA) in 9 patients with cardiac transplants were reviewed. Primary total joint arthroplasties were performed for osteonecrosis (5 hips) or osteoarthritis (5 hips, 4 knees). There were no infections in any of these patients. Final Harris Hip Scores were 71.8 for patients with osteonecrosis and 88.6 for osteoarthritis. Eight of 10 hips were pain-free at final follow-up. Two of the 10 primary THAs required late revision at 7 and 10 years after the index arthroplasty. One patient (2 hips and 1 knee) had chronic bilateral lower extremity pain. Total knee arthroplasty range of motion averaged from 7.5° to 118°. Average final Knee Society function score was 79, and objective score was 88. One of 4 patients with primary TKA required a manipulation under anesthesia. No reoperations were required in this group. Overall, patients with heart transplantations on immunosuppression had generally good pain relief after THA and TKA. There were no infections in this small cohort; however, there were many complications.

Case We describe a case of septic hip arthritis and enterocutaneous fistula formation caused by the seeding of a hip joint during hip arthroscopy performed in the setting of a psoas abscess. Treatment consisted of multiple debridements and femoral head resection with subsequent total hip arthroplasty. Conclusions This case highlights the importance of a thorough history, physical examination, and assessment of available imaging before proceeding to surgery, even when the procedure is one considered to have minimal risks, such as arthroscopy.

To evaluate the effects of the economic downturn on adult reconstruction surgery in the United States, a survey of the American Association of Hip and Knee Surgeons (AAHKS) membership was conducted. The survey evaluated surgical and patient volume, practice type, hospital relationship, total joint arthroplasty cost control, employee staffing, potential impact of Medicare reimbursement decreases, attitudes toward health care reform options and retirement planning. A surgical volume decrease was reported by 30.4%. An outpatient visit decrease was reported by 29.3%. A mean loss of 29.9% of retirement savings was reported. The planned retirement age increased to 65.3 years from 64.05 years. If Medicare surgeon reimbursement were to decrease up to 20%, 49% to 57% of AAHKS surgeons would be unable to provide care for Medicare patients, resulting in an unmet need of 92,650 to 160,818 total joint arthroplasty procedures among AAHKS surgeons alone. Decreases in funding for surgeons and inadequate support for subspecialty training will likely impact access and quality for Americans seeking adult reconstruction surgery.

Background: Hyponatremia is common among orthopaedic patients and is associated with adverse clinical outcomes. We examined the prevalence, timing, causes, and outcomes of hyponatremia in adult hospitalized orthopaedic surgery patients. Methods: We evaluated the medical records of 1067 consecutive orthopaedic surgery patients admitted to a tertiary academic institution. The medical records were reviewed to investigate hyponatremia (serum sodium

Background: Bipolar hip arthroplasty has been advocated by some as an alternative to total hip arthroplasty for the treatment of degenerative arthritis of the hip. We sought to assess the results of this procedure at our institution after a minimum duration of follow-up of ten years. Methods: We retrospectively reviewed a consecutive series of 152 patients (173 hips) who underwent primary bipolar hemiarthroplasty for the treatment of symptomatic degenerative arthritis of the hip with a cementless femoral component between 1983 and 1987. Of the original cohort of 152 patients, ninety-two patients (104 hips) were available for clinical and radiographic review at a mean of 12.2 years postoperatively. At the time of the latest follow-up, self-administered Harris hip questionnaires were used to assess pain, mobility, activity level, and overall satisfaction with the procedure. Biplanar hip radiographs were made to evaluate bipolar shell migration, osteolysis, and femoral stem fixation. Results: At the time of the latest follow-up, nineteen patients (nineteen hips) had undergone revision to total hip arthroplasty because of mechanical failure, and three patients (three hips) were awaiting revision because of symptomatic radiographic mechanical failure. Twelve acetabular revisions were performed or scheduled for the treatment of pelvic osteolysis or protrusio acetabuli secondary to component migration. Acetabular reconstruction required bone-grafting, an oversized shell, and/or a pelvic reconstruction ring. The overall rate of mechanical failure was 21.2% (twenty-two of 104 hips), with 91% (twenty) of the twenty-two failures involving the acetabular component. Reaming of the acetabulum at the time of the index arthroplasty was associated with a 6.4-fold greater risk of revision. The rate of implant survival, with revision because of mechanical failure as the end point, was 94.2% for femoral components and 80.8% for acetabular components at a mean of 12.2 years. Of the remaining sixty-nine patients (eighty-one hips) in whom the original prosthesis was retained, seventeeen patients (24.6%) rated the pain as moderate to severe. Nearly 30% of patients with an intact prosthesis required analgesics on a regular basis. Radiographs were available for fifty-eight hips (including all of the hips with moderate to severe pain) after a minimum duration of follow-up of ten years; twenty-eight of these fifty-eight hips had radiographic evidence of acetabular component migration. Conclusions: This bipolar cup, when used for hemiarthroplasty in patients with symptomatic arthritis of the hip, was associated with unacceptably high rates of pain, migration, osteolysis, and the need for revision to total hip arthroplasty, especially when the acetabulum had been reamed. To the extent that these findings can be generalized to similar implant designs with conventional polyethylene, we do not recommend bipolar hemiarthroplasty as the primary operative treatment for degenerative arthritis of the hip. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Management of periprosthetic fractures around the knee is often difficult because of poor bone quality, comminution, and constraints imposed by the existing prosthesis. Locked condylar plates may provide more reliable fixation for these fractures than traditional methods of fixation. Eleven patients with periprosthetic fractures around the knee were treated with open reduction and internal fixation using a locked condylar plate. All 9 acute fractures and 1 of 2 periprosthetic nonunions healed at an average of 21 weeks, and no patient required additional surgery. Nine fractures healed in anatomical alignment, whereas 1 healed in 5 degrees valgus. The remaining periprosthetic nonunion developed a persistent nonunion with subsequent hardware failure. The average range of motion was 4 degrees to 92 degrees . Locked plating systems are highly effective for the management of complex periprosthetic fractures around the knee. They result in reliable fracture healing and permit early motion in complex fractures.

Background: The long-term results of revision of failed primary cemented femoral components with use of cement have been reported, but there is little information about the results of revision of failed uncemented femoral components with use of cement. The purpose of the present study was to examine the minimum five-year results for patients in whom a failed uncemented primary femoral component was revised with use of modern cementing techniques. Methods: Forty-eight consecutive hips (forty-seven patients) in which a failed primary uncemented femoral component was revised with use of cement at one institution from 1985 to 1992 were followed prospectively and reviewed retrospectively. The mean age of the patients at the time of revision was sixty-seven years. Only seven revisions were performed with a long-stem femoral component. The postoperative cement mantle was classified, according to the system of Mulroy and Harris, as grade A in four hips, grade B in twenty-five, grade C1 in seven, grade C2 in twelve, and grade D in none. Results: Eleven femoral components were removed or revised because of aseptic loosening (ten) or deep infection (one). An additional four unrevised femoral components had evidence of probable or definite loosening at the time of the final radiographic follow-up. Thus, fourteen (29%) of the forty-eight femoral implants demonstrated aseptic loosening during the study period. Five of the twenty-nine hips in which the postoperative cement mantle was classified as grade A or B had mechanical failure at the time of the final follow-up, compared with nine of the nineteen hips in which the postoperative cement mantle was classified as grade C1 or C2 (p < 0.05). Among the hips with surviving prostheses, 79% had had moderate or severe pain preoperatively whereas 25% had moderate or severe pain at the time of the final follow-up. The six-year rate of survival of the femoral component was 72% with revision for aseptic loosening as the end point and 67% with mechanical failure (revision for aseptic loosening or radiographic loosening) as the end point. Conclusions: While revision of a failed uncemented femoral implant with use of cement provided pain relief and improved function for most patients, the rate of loosening at the time of intermediate-term follow-up was higher than that commonly reported after revision of failed cemented implants with use of cement and also was higher than that commonly reported after revision with use of uncemented extensively porous-coated implants. Bone removal at the time of the initial implantation of the stem and bone loss due to subsequent failure of the uncemented implant often left little intramedullary cancellous bone, which may explain the high rate of loosening observed in the first decade after revision in this series. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

The purpose of this study was to evaluate the economic attributes of private practice adult reconstruction (AR) offices. 458 AAHKS surgeons responded; 65% were in private practice (fee-for-service, non-salaried, non-employed AR surgeons). 54% had considered hospital employment in the past two years. The average group employs 13.4 orthopedic surgeons (3.4 AR), and 105 other employees. The average total budget is $12.5 million per year with $4 million in salaries, and $238,000 in tax revenue generated. Co-management joint ventures are a better model than hospital employment for aligning AR surgeons and hospitals and realizing the cost effectiveness and quality improvement goals of PPACA and AARA while preserving the economic impact of AR private practice.

In acute periprosthetic infection, irrigation and debridement with component retention has a high failure rate in some studies. We hypothesize that pulse lavage irrigation is ineffective at removing biofilm from total knee arthroplasty (TKA) components. Staphylococcus aureus biofilm mass and location was directly visualized on arthroplasty materials with a photon collection camera and laser scanning confocal microscopy. There was a substantial reduction in biofilm signal intensity, but the reduction was less than a ten-fold decrease. This suggests that irrigation needs to be further improved for the removal of biofilm mass below the necessary bioburden level to prevent recurrence of acute infection in total knee arthroplasty.

Background: Hip fractures are common in the elderly, and patients with hip fractures frequently have comorbid illnesses. Little is known about the relationship between comorbid illness and hospital costs or length of stay following the treatment of hip fracture in the United States. We hypothesized that specific individual comorbid illnesses and multiple comorbid illnesses would be directly related to the hospitalization costs and the length of stay for older patients following hip fracture. Methods: With use of discharge data from the 2007 Nationwide Inpatient Sample, 32,440 patients who were fifty-five years or older with an isolated, closed hip fracture were identified. Using generalized linear models, we estimated the impact of comorbidities on hospitalization costs and length of stay, controlling for patient, hospital, and procedure characteristics. Results: Hypertension, deficiency anemias, and fluid and electrolyte disorders were the most common comorbidities. The patients had a mean of three comorbidities. Only 4.9% of patients presented without comorbidities. The average estimated cost in our reference patient was $13,805. The comorbidity with the largest increased hospitalization cost was weight loss or malnutrition, followed by pulmonary circulation disorders. Most other comorbidities significantly increased the cost of hospitalization. Compared with internal fixation of the hip fracture, hip arthroplasty increased hospitalization costs significantly. Conclusions: Comorbidities significantly affect the cost of hospitalization and length of stay following hip fracture in older Americans, even while controlling for other variables. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Wear-induced osteolysis remains a common problem after total knee arthroplasty and may be particularly difficult to detect clinically or radiographically around the femoral component. We describe the use of magnetic resonance imaging to identify particulate-induced osteolysis around the distal femur and proximal tibia in 2 patients with total knee arthroplasties. The extent of the osteolysis was not apparent from standard x-rays, and the information provided by the magnetic resonance imaging facilitated preoperative discussion with the patient as well as preoperative planning for the surgery.

Many patients with severe cardiac disease can now live for a prolonged period with left ventricular assist devices (LVADs), and some patients will develop noncardiac medical issues that may benefit from surgical intervention. Previous studies have reported a low rate of complications in patients with LVADs undergoing noncardiac surgical procedures. We report the cases of 2 patients with LVADs who underwent total knee arthroplasties for osteoarthritis. Both patients had significant pain relief and improved function; however, management of anticoagulation and bleeding complications was challenging.

A 2008 survey of American Association of Hip and Knee Surgeons membership explored current venous thromboembolism (VTE) protocols for lower-extremity total joint surgery. Fifty-three percent reported a change in VTE-related practices in the last 5 years. More than 70% reported that their primary hospital now mandates VTE prophylaxis. Although 74% of their primary hospitals recognized the American College of Chest Physicians guidelines, 68% of surgeons felt the American Academy of Orthopaedic Surgeons guidelines were more relevant to their practice. Respondents believe low molecular weight heparin to be the most efficacious but aspirin to be the easiest to use and has the lowest risks of bleeding and wound drainage. Warfarin was the most used in hospital prophylaxis, and 90% of respondents targeted an international normalized ratio of 1.6 to 2.5. Practice patterns continue to evolve, and there remains no consensus on specific treatment protocols or preferences.

A technique for ipsilateral femoral neck and shaft fracture using the sliding compression hip screw with plate combined with trochanteric antegrade Ender nailing of the femur was applied in two cases. Ender nails can be passed without difficulty past a compression hip screw and the bicortical plating screws. The hip and femur can be fixed internally through a single approach in a single position. Sliding compression hip screw devices can provide excellent preliminary stable femoral neck fixation. Blood supply to the femoral head is not disturbed while the femoral intramedullary fixation is performed. Antegrade Ender nailing avoids the common knee complications associated with other retrograde techniques. Decreased operative time, less blood loss, less technical difficulty, and early mobilization are important factors in the multiple-injured patient. Femoral intramedullary fixation may require open reduction, circlerage to ensure stability, and maintenance of alignment in case of significant comminution to allow early crutch ambulation. This mode of fixation may be advantageous for selected cases.