Trabecular Metal Augments During Complex Primary Total Hip Arthroplasty.

Background: Trabecular metal augments (TMAs) have been extensively used in revision total hip arthroplasty (THA) to address acetabular bone defects. However, limited data exists regarding TMA utilization during primary THA. This study aims to assess the clinical and radiographic outcomes of TMAs used during primary THA. Methods: A single-institution retrospective case series of primary THA patients treated with TMA between 2010 and 2019 was performed. Patient demographics, complications, and revisions were recorded. Cup position, center of rotation, leg length, and radiolucent lines were assessed radiographically. The Kaplan-Meier method was used to compute implant survivorship. Results: Twenty-six patients (30 hips) were included with average age of 52.6 ± 15.3 years (range: 22-78) and mean follow-up of 4.1 ± 2.1 years (range: 2.0-8.9). Most TMAs were indicated for developmental dysplasia of the hip (n = 18; 60.0%). On average, hip center of rotation was lowered 1.5 ± 1.3 cm and lateralized 1.2 ± 1.5 cm, while leg length and global offset were increased by 2.4 ± 1.2 cm and 0.4 ± 1.0 cm, respectively. At final follow-up, 3 hips (10.0%) required revision: one (3.3%) for aseptic loosening and 2 (6.7%) for instability. No patients had progressive radiolucent lines at final follow-up. Five-year survival with aseptic loosening and all-cause revision as endpoints was 100% (95% confidence interval: 90.0%-100.0%) and 92.1% (95% confidence interval: 81.3%-100.0%), respectively. One patient required revision for aseptic loosening after the 5-year mark. Conclusions: Trabecular metal augmentation during primary THA demonstrates satisfactory early to mid-term outcomes. TMA is a viable option for complex primary THA when bone loss is encountered or secondary support is required. Level of Evidence: Level IV.

Limited Durability of Extensor Mechanism Reconstruction Following Total Knee Arthroplasty: Mesh and Allograft Show Equivalent Outcomes at Five-Year Follow-Up.

BACKGROUND: Extensor mechanism disruption is a challenging complication following total knee arthroplasty. The purpose of this study was to compare outcomes between patients who received mesh versus allograft extensor mechanism reconstruction. METHODS: All patients who underwent extensor mechanism reconstruction at a single institution were screened. Demographic and surgical variables were recorded, including technique (ie, synthetic mesh versus allograft reconstruction). Patients were assessed for preoperative and postoperative extensor lag, revision, and duration of follow-up. Analyses, including Kaplan-Meier survivorships, were performed to compare mesh to allograft reconstruction. In total, 50 extensor mechanism reconstructions (30 mesh and 20 allograft) were conducted between January 1st, 2001, and December 31st, 2022. RESULTS: There were no differences between the cohorts with respect to revision (26.7 [8 of 30] versus 35.0% [7 of 20], P = .680) or failure defined as above knee amputation or fusion (6.7 [2 of 30] versus 5.0% [1 of 20], P = .808). There were also no differences in time to reoperation (average 27 months [range, 6.7 to 58.8] versus 29 months [range, 1.2 to 84.9], P = .910) or in postoperative extensor lag among patients who did not undergo a reoperation (13 [0 to 50] versus 11° [0 to 30], P = .921). The estimated 5-year Kaplan-Meier survival with extensor mechanism revision as the endpoint was similar between the 2 groups (52.1, 95% confidence interval [CI] = 25.4 to 73.3 versus 55.0%, 95% CI = 23.0 to 78.4%, P = .990). CONCLUSIONS: The purpose of this study was to present the findings of a large cohort of patients who required extensor mechanism reconstruction. Regardless of the reconstruction type, the 5-year outcomes of patients requiring extensor mechanism reconstruction are suboptimal.

Factors Associated With Failure Following Proximal Femoral Replacement for Salvage Hip Surgery for Nononcologic Indications.

BACKGROUND: Proximal femoral replacement (PFR) is used when extensive proximal femoral bone loss is encountered during revision total hip arthroplasty. However, further data on 5-to-10-year survivorship and predictors of failure are needed. Our aim was to assess the survivorship of contemporary PFRs used for nononcologic indications and determine factors associated with failure. METHODS: A single-institution retrospective observational study was conducted between June 1, 2010 and August 31, 2021 for patients undergoing PFR for non-neoplastic indications. Patients were followed for a minimum of 6 months. Demographic, operative, clinical, and radiographic data were collected. Implant survivorship was determined via Kaplan-Meier analysis of 56 consecutive cemented PFRs in 50 patients. RESULTS: At a mean follow-up of 4 years, the mean Oxford Hip Score was 36.2 and patient satisfaction was rated at an average of 4.7 of 5 on the Likert scale. Radiographic evidence of femoral-sided aseptic loosening was determined in 2 PFRs at a median of 9.6 years. The 5-year survivorship with all-cause reoperation and revision as end points was 83.2% (95% Confidence Interval [CI]: 70.1% to 91.0%) and 84.9% (95% CI: 72.0% to 92.2%), respectively. The 5-year survivorship was 92.3% (95% CI: 78.0% to 97.5%) for stem length > 90 mm compared to 68.4% (95% CI: 39.5% to 85.7%) for stem length ≤ 90 mm. A construct-to-stem length ratio (CSR) ≤ 1 was associated with a 91.7% (95% CI: 76.4% to 97.2%) survival, while a CSR > 1 was associated with a 73.6% (95% CI: 47.4% to 88.1%) survival. CONCLUSION: A PFR stem length ≤ 90 mm and CSR > 1 were associated with increased rates of failure.

Positive COVID-19 Diagnosis Following Primary Elective Total Joint Arthroplasty: Increased Complication and Mortality Rates.

BACKGROUND: This study analyzed complication rates following primary elective total joint arthroplasty (TJA) in patients who subsequently contracted COVID-19. METHODS: A large national database was queried for adult patients who underwent primary elective TJA in 2020. Patients who contracted COVID-19 after total knee arthroplasty (TKA) or total hip arthroplasty (THA) underwent 1:6 matching (age [±6 years], sex, month of surgery, COVID-19-related comorbidities) to patients who did not. Differences between groups were assessed using univariate and multivariate analyses. Overall, 712 COVID-19 patients were matched to 4,272 controls (average time to diagnosis: 128-117 days [range, 0-351]). RESULTS: Of patients diagnosed <90 days postoperatively, 32.5%-33.6% required COVID-19-driven readmission. Discharge to a skilled nursing facility (adjusted odds ratio [aOR] 1.72, P = .003) or acute rehabilitation unit (aOR 4.93, P < .001) and Black race (aOR 2.28, P < .001) were associated with readmission after TKA. Similar results were associated with THA. COVID-19 patients were at increased risk of pulmonary embolism (aOR 4.09, P = .001) after TKA and also periprosthetic joint infection (aOR 4.65, P < .001) and sepsis (aOR 11.11, P < .001) after THA. The mortality rate was 3.51% in COVID-19 patients and 7.94% in readmitted COVID-19 patients compared to 0.09% in controls, representing a 38.7 OR and 91.8 OR of death, respectively. Similar results were observed for TKA and THA separately. CONCLUSION: Patients who contracted COVID-19 following TJA were at greater risk of numerous complications, including death. These patients represent a high-risk cohort who may require more aggressive medical interventions. Given the potential limitations presently, prospectively collected data may be warranted to validate these findings.

The Persistent Effects of the COVID-19 Pandemic on Total Joint Arthroplasty Changes in Practice Patterns in the United States From 2020 to 2021.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic has dramatically disrupted orthopaedic surgery practice patterns. This study aimed to examine differences between patients who underwent total joint arthroplasty (TJA) before the pandemic compared to 2020 and 2021. METHODS: A retrospective cohort study was performed on all patients who underwent elective inpatient TJA from January 2017 to December 2021 using a national large database. Descriptive statistics were utilized to trend length of stay (LOS) and patient age. Patient demographics, discharge destinations, and rates of medical comorbidities were assessed for patients undergoing TJA in 2020 and 2021 compared to patients from prepandemic years (2017 to 2019). Overall, 1,173,366 TJAs were identified (2017 to 2019: 810,268 TJAs, average 270,089 cases/year; 2020: 175,185 TJAs; 2021: 187,627 TJAs). There was a 35.3% and 30.5% decrease in 2020 and 2021, respectively, when compared to the prepandemic annual average. RESULTS: Average LOS decreased from 1.6 days in January 2020 to 0.9 days by December 2021. Same-day discharges increased from 6.2% of cases in 2019 to 30.5% in 2021. Discharge to skilled nursing facilities (SNF) reduced from 11.3% in 2017 to 2019 to 4.3% and 4.5% in 2020 and 2021, respectively. Patients ≥70 years old undergoing elective TJA decreased from 39.6% in 2017 to 2019 to 29.2% in April 2020. CONCLUSION: In response to the COVID-19 pandemic, same-day discharges following primary elective TJA increased markedly, the average LOS decreased, discharges to SNFs decreased, and a preferential shift toward younger patients was observed. LEVEL OF EVIDENCE: Therapeutic Level III.

Influence of donor age and comorbidities on transduced human adipose-derived stem cell in vitro osteogenic potential.

Human adipose-derived mesenchymal stem cells (ASCs) transduced with a lentiviral vector system to express bone morphogenetic protein 2 (LV-BMP-2) have been shown to reliably heal bone defects in animal models. However, the influence of donor characteristics such as age, sex, race, and medical co-morbidities on ASC yield, growth and bone regenerative capacity, while critical to the successful clinical translation of stem cell-based therapies, are not well understood. Human ASCs isolated from the infrapatellar fat pads in 122 ASC donors were evaluated for cell growth characteristics; 44 underwent additional analyses to evaluate in vitro osteogenic potential, with and without LV-BMP-2 transduction. We found that while female donors demonstrated significantly higher cell yield and ASC growth rates, age, race, and the presence of co-morbid conditions were not associated with differences in proliferation. Donor demographics or the presence of comorbidities were not associated with differences in in vitro osteogenic potential or stem cell differentiation, except that transduced ASCs from healthy donors produced more BMP-2 at day 2. Overall, donor age, sex, race, and the presence of co-morbid conditions had a limited influence on cell yield, proliferation, self-renewal capacity, and osteogenic potential for non-transduced and transduced (LV-BMP-2) ASCs. These results suggest that ASCs are a promising resource for both autologous and allogeneic cell-based gene therapy applications.

Tranexamic Acid and Prothrombotic Complications Following Total Hip and Total Knee Arthroplasty: A Population-Wide Safety Analysis Accounting for Surgeon Selection Bias.

BACKGROUND: Tranexamic acid (TXA) utilization during total joint arthroplasty (TJA) has become ubiquitous. However, concerns remain regarding the risk of thrombotic complications. The goal of this study was to examine the risk of prothrombotic complications in patients who received TXA during total knee (TKA) and total hip arthroplasty (THA). METHODS: The Premier Healthcare Database was queried for patients who underwent elective TJA. TXA utilization trends were described from 2008 to 2020. Two analyses were performed using ICD-10 codes from 2016 to 2020: (1) patients who received TXA compared to patients who did not receive TXA and, (2) to account for surgeon selection bias, patients whose surgeon utilized TXA consistently (≥90% of cases) compared to patients whose surgeons used TXA infrequently (≤30% of cases). Multivariate and instrumental variable analyses (IVA) were performed to assess outcomes while accounting for confounding factors. TXA utilization increased from 0.1% of cases in 2008 to 89.2% in 2020. From 2016 to 2020, 1,120,858 TJAs were identified (62.1% TKA, 27.9% THA), of which 874,627 (78.0%) received TXA. RESULTS: Patients who received TXA were at lower risk of prothrombotic (adjusted Odds Ratio (aOR) 0.82, P < .001), bleeding (aOR 0.75, P < .001), and infectious complications (aOR 0.91, P < 0.001). Furthermore, patients who underwent surgery from surgeons who utilized TXA consistently were at lower risk for prothrombotic (aOR 0.90, P < .001) and bleeding (aOR 0.72, P < .001) complications. CONCLUSION: The widespread utilization of TXA during elective TJA was not associated with increased rates of prothrombotic complications. These findings persisted after accounting for surgeon selection bias. LEVEL OF EVIDENCE: Level III.

Monomicrobial Joint Infection by Leclercia adecarboxylata in an Immunocompetent Patient After Knee Arthroscopy: A Case Report.

CASE: A 54-year-old immunocompetent man presented to the office with severe right knee pain and swelling 27 days after knee arthroscopy. Additional diagnostics identified a monomicrobial infection of the right knee joint by the bacterium Leclercia adecarboxylata, which was later confirmed by repeated aspiration of the joint and culture of the aspirated fluid. CONCLUSION: This case report details a postoperative monomicrobial infection with L. adecarboxylata after a knee arthroscopy in an immunocompetent host. Although infection by this bacterium is rare, this case demonstrates the possibility of L. adecarboxylata infection in the knee joint after orthopaedic surgery.

Elective Inpatient Total Joint Arthroplasty Case Volume in the United States in 2020: Effects of the COVID-19 Pandemic.

BACKGROUND: Despite known surgical volume reductions in 2020 during the height of the COVID-19 pandemic, no study has fully quantified the impact of the pandemic on the number of elective inpatient total hip (THA) and total knee arthroplasty (TKA) cases. The purpose of the present study was to analyze THA and TKA case volumes in the United States during the COVID-19 pandemic. METHODS: The Premier Healthcare Database was utilized to identify adults undergoing primary elective THA or TKA from January 2017 to December 2020. The National Inpatient Sample was cross-referenced to provide nationwide representative sampling weights. Patients undergoing revision total joint arthroplasty (TJA) or non-elective surgery were excluded. Two quantitative models were created from both databases to estimate TJA case volume in 2020. Descriptive statistics were utilized to report monthly changes in elective TJA utilization throughout 2020. Univariate analyses were performed to compare differences between subgroups. RESULTS: From 2017 to 2019, it was estimated that 1,006,000 elective inpatient TJAs (64.2% TKA and 35.8% THA) were performed annually. In 2020, an estimated 526,000 to 538,000 cases (62.0% TKA and 38.0% THA) were performed, representing a 46.5% to 47.7% decrease in nationwide volume from the prior 3-year average. Moreover, the elective TJA case volume for April 2020 was 1.9% of the average for that month from 2017 through 2019. Subsequently, case volumes for May and June increased compared with the volumes for those months from 2017 through 2019. There was then a decrease in cases for July, corresponding with the "second wave" of COVID-19, followed by an additional steady monthly decline through December, corresponding with the "third wave." Finally, the elective TJA cases for December 2020 represented only 41.0% of the average case volume for that month from 2017 through 2019. CONCLUSIONS: In the midst of the 2020 COVID-19 pandemic, approximately 526,000 to 538,000 elective inpatient TJA cases were performed, representing a 46.5% to 47.7% decrease compared with the 3 previous years. The effects of the COVID-19 pandemic persisted through the end of that year, with decreased case volume through December 2020.

Modern Proximal Femoral Replacement in Revision Total Hip Arthroplasty for Nononcologic Indications.

BACKGROUND: Advances in surgical technique and prosthesis design have expanded the non-neoplastic indications for proximal femoral replacement (PFR) to include fracture nonunion, periprosthetic fracture, and severe bone loss in the setting of revision total hip arthroplasty (THA). The purpose of this study is to assess outcomes of PFRs used for nononcologic indications. METHODS: A single-institution, retrospective, cohort survey study was conducted between August 2015-February 2020 of consecutive patients undergoing PFR for nononcologic indications in revision THA. Patient demographics, surgical variables, complications, and revision procedures were collected. Patient satisfaction and Oxford Hip scores were assessed via a telephone questionnaire. Implant survivorship was estimated using the Kaplan-Meier method. RESULTS: In total, 24 patients (27 PFRs) were available for analysis with an average age of 69.3 ± 12.9 years (range: 37-90). The average number of operations prior to PFR implantation was 3.1 ± 2.1 (range: 0-7). At a mean follow-up of 2.4 years (range: 0.5-5.1), the mean Oxford Hip Score was 31.7 ± 10.2, and mean patient satisfaction was 4.9/5. Six patients (20.7%) experienced a postoperative complication, with dislocation occurring in three patients (10.3%). None of the patients with dual mobility articulations (n = 4) had dislocation. Three-year survivorship was 85.2% (95% CI 71.8%-98.6%) with all-cause reoperations as the endpoint and 100% (95% CI 100.0%-100.0%) with revision for aseptic loosening as the endpoint. CONCLUSION: The current study demonstrates excellent short-term survivorship, satisfactory patient-reported outcomes, and high patient satisfaction following PFR for nononcologic indications during revision THA utilizing modern techniques. The most common mode of failure was dislocation requiring reoperation with revision to constrained acetabular components.

Patient Perception Regarding the Safety of Elective Joint Arthroplasty Surgery During the COVID-19 Pandemic.

BACKGROUND: Total joint arthroplasty (TJA) practices have been dramatically impacted by the COVID-19 pandemic. To date, no study has assessed trends in patient perceptions regarding the safety of elective TJA. METHODS: A single-institution, prospective cohort study was conducted between May 11th and August 10th, 2020. All patients who underwent elective hip and knee arthroplasty were contacted via telephone or emailed surveys. Two-hundred and thirty-five consecutive patients were screened, and 158 agreed to participate. The average age was 65.9 ± 11.5 years, with 51.0% of patients being female. The percentage of participants who underwent total knee, total hip, and unicompartmental knee arthroplasty was 41.4%, 37.6%, and 21.0%, respectively. Survey components assessed demographic data, level of concern and specific concerns about the pandemic, and factors increasing patient comfort in proceeding with surgery. RESULTS: Older age (P = .029) and female sex (P = .004) independently predicted higher concern on multivariate analysis. Race (P = .343), surgical site (knee vs hip, P = .58), and procedure type (primary vs revision, P = .26) were not significantly related to degree of concern. Most participants (71.5%) disagreed that the pandemic would negatively affect the outcome of their surgery. Patient concern mirrored statewide COVID-19 cases and deaths, rather than local municipal trends. The most cited reassuring factors were preoperative COVID-19 testing, personal protective equipment usage by hospital staff, and surgeon support. CONCLUSIONS: Patient concern regarding the safety of elective TJA may follow broader policy-level events rather than local trends. Surgeons should note that universal preoperative COVID-19 testing, adequate personal protective equipment, and surgeon support were reassuring to patients. LEVEL OF EVIDENCE: Level IV Therapeutic.

Dose-Dependent Early Postoperative Opioid Use Is Associated with Periprosthetic Joint Infection and Other Complications in Primary TJA.

BACKGROUND: Opioids are commonly prescribed for postoperative pain following total joint arthroplasty. Despite widespread use, few studies have examined the dose-dependent effect of perioperative opioid use on postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Therefore, we examined the dose-dependent relationship between opioid use and postoperative complications following primary THA and TKA. METHODS: We queried the Premier Healthcare Database to identify adult patients who underwent primary elective THA or TKA from 2004 to 2014, and quantified opioid consumption within the first 3 postoperative days. Opioid consumption was standardized to morphine milligram equivalents (MMEs). Patients were divided into quintiles on the basis of MME exposure: <54, 54 to 82, 83 to 116, 117 to 172, and >172 MMEs. Primary outcomes included postoperative periprosthetic joint infection, pulmonary embolism, deep venous thrombosis, and pulmonary complications. Secondary outcomes included wound infection, wound dehiscence, and readmission within 30 and 90 days postoperatively. Univariate and multivariate analyses were performed to compare differences between groups and to account for confounders. RESULTS: A total of 1,525,985 patients were identified. The mean age was 65.7 ± 10.8 years, 598,320 patients (39.2%) were male, and 1,174,314 patients (77.0%) were Caucasian. On multiple logistic regression analysis, increasing MME exposure was associated with a dose-dependent increased risk of postoperative complications. Compared with patients receiving <54 MMEs, exposure to >172 MMEs was associated with greater odds of periprosthetic joint infection (adjusted odds ratio [aOR], 1.37; 95% confidence interval [CI], 1.33 to 1.42), deep venous thromboembolism (aOR, 1.34; 95% CI, 1.30 to 1.38), pulmonary embolism (aOR, 1.29; 95% CI, 1.25 to 1.34), and pulmonary complications (aOR, 1.06; 95% CI, 1.05 to 1.08). Exposure to >172 MMEs was associated with increased risk of wound infection (aOR, 1.37; 95% CI, 1.33 to 1.41), wound dehiscence (aOR, 1.24; 95% CI, 1.19 to 1.31), and readmission within 30 (aOR, 1.21; 95% CI, 1.20 to 1.22) and 90 days (aOR, 1.20; 95% CI, 1.19 to 1.21). CONCLUSIONS: Increasing opioid use within the early postoperative period following THA or TKA was associated with a dose-dependent increased risk of periprosthetic joint infection and venous thromboembolic events. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Population-based Survivorship of Computer-navigated Versus Conventional Total Knee Arthroplasty.

BACKGROUND: The goal of computer navigation in total knee arthroplasty (TKA) is to improve the accuracy of alignment. However, the relationship between this technology and implant longevity has not been established. The purpose of this study was to analyze survivorship of computer-navigated TKAs compared with traditionally instrumented TKAs. METHODS: The PearlDiver Medicare database was used to identify patients who underwent a primary TKA using conventional instrumentation versus computer navigation between 2005 and 2014. Conventional and computer-navigated cohorts were matched by age, sex, year of procedure, comorbidities, and geographic region. Kaplan-Meier curves were generated to estimate survivorship with aseptic mechanical complications, periprosthetic joint infection, and all-cause revision as end points. RESULTS: During the study period, 75,709 patients who underwent a computer-navigated TKA were identified and matched to a cohort of 75,676 conventional TKA patients from a cohort of 1,607,803 conventional TKA patients. No difference existed in survival between conventional instrumentation (94.7%) and navigated TKAs (95.1%, P = 0.06) at 5 years. A modest decrease was found in revisions secondary to mechanical complications associated with navigation (96.1%) compared with conventional instrumentation (95.7%, P = 0.02) at 5 years. No differences in revision rates because of periprosthetic joint infection were observed (97.9% versus 97.9% event-free survival, P = 0.30). In a subgroup of Medicare patients younger than 65 years of age, use of computer navigation was associated with a decrease in all-cause revision (91.4% versus 89.6% event free survival, P = 0.01) and revision secondary to mechanical complications (89.6% versus 87.8% event-free survival, P = 0.01) at 5 years. DISCUSSION: Among Medicare patients, no notable difference existed in TKA survival associated with the use of computer navigation at the 5-year follow-up. Use of computer navigation was associated with a slight decrease in revisions secondary to mechanical failure. Although improved survivorship was associated with patients younger than 65 years of age who had a navigated TKA, generalizability of these findings is limited given the unique characteristics of this Medicare subpopulation.

Complex Reconstruction of the Knee with a Free Vertical Rectus Abdominis Flap after Periprosthetic Soft Tissue Necrosis.

Periprosthetic joint infection (PJI) is limb threatening and difficult to treat. Although a two-stage re-implantation is accepted as the standard of care for PJI, extensive debridement, numerous surgeries, or liquifactive necrosis from the infection can result in a tissue defect. With a large tissue defect, soft tissue coverage is required to protect the prosthesis, fill any dead space, and obtain a satisfactory wound closure. With defects too large for local or regional flap coverage, free tissue transfer is the best option. We present a case in which soft tissue coverage with both medial and lateral gastrocnemius muscle flaps was not sufficient; free tissue transfer was necessary for both wound closure and creation of an adequate soft tissue envelope for the future placement of a prosthesis. Regardless of the complicated surgical history and extensive soft tissue damage, limb function was restored and the patient regained his independence.

Systematic Review and Meta-Analysis of Intrawound Vancomycin in Total Hip and Total Knee Arthroplasty: A Call for a Prospective Randomized Trial.

BACKGROUND: Topical intrawound vancomycin has been used extensively in spine surgery to decrease surgical site infections. However, the efficacy of intrawound vancomycin in total hip (THA) and total knee arthroplasty (TKA) to prevent periprosthetic joint infection (PJI) has not been established. METHODS: The PubMed and MEDLINE databases were searched to identify studies utilizing intrawound vancomycin in primary and revision THA and TKA. Data for postoperative infection were pooled using random effect models with results reported as odds ratios (ORs) and 95% confidence intervals. Studies were weighted by the inverse variance of their effect estimates. RESULTS: Of the 91 studies identified, 6 low-quality retrospective studies (level III) were pooled for further analysis. A total of 3298 patients were assessed, 1801 of which were treated with intrawound vancomycin. Overall, patients who received vancomycin had a decreased rate of PJI (OR 0.2530, P < .0001). When analyzed separately, TKA patients and THA patients who received intrawound vancomycin had lower rates of PJI (OR 0.3467, P = .0005 and OR 0.3672, P = .0072, respectively). Pooled primary TKA and THA patients receiving vancomycin saw the rate of PJI decrease (OR 0.4435, P = .0046). Pooled revision TKA and THA patients saw a similar decrease in infection rates (OR 0.2818, P = .0013). No apparent publication bias was observed; however, the results from this analysis are limited by the low quality of evidence and inherent potential for bias. CONCLUSION: Intrawound vancomycin may reduce the risk of PJI in primary and revision TKA and THA. However, only low-quality evidence exists, highlighting the need for randomized controlled trials before broad adoption of this practice can be recommended given the potential implications of widespread use of vancomycin in hip and knee arthroplasty.

In vitro evaluation of a lentiviral two-step transcriptional amplification system using GAL4FF transactivator for gene therapy applications in bone repair.

In this study, we developed a lentiviral two-step transcriptional amplification (TSTA) system expressing bone morphogenetic protein-2 (BMP-2) under the control of a GAL4FF transactivator to enhance gene expression and limit toxicity for bone repair applications. To this end human MSCs, isolated from bone marrow or adipose tissue, were transduced overnight with a LV-TSTA system (GAL4FF or GAL4vp16) expressing BMP-2 or GFP and evaluated in vitro for transduction efficiency, mean fluorescence intensity, cell viability, and BMP-2 production. FACS analysis of GFP-transduced MSCs confirmed successful transduction with the GAL4FF+GFP vector. Moreover, ELISA demonstrated abundant BMP-2 production by GAL4FF+BMP2-transduced human MSCs over a period of 8 weeks, with minimal cytotoxicity at all time points. Compared to GAL4vp16, GAL4FF was superior with respect to BMP production at 1, 2, 4, 6, and 8 weeks in BMSCs. In ASCs, GAL4FF was still associated with higher BMP-2 production at weeks 2-8, but this difference was not as prominent as in BMSCs. To our knowledge, this is the first report of GAL4FF-mediated BMP-2 production by human BMSCs and ASCs. Compared to the standard GAL4vp16TSTA vector, GAL4FF was associated with lower cytotoxicity and higher in vitro gene expression in both BMSCs and ASCs.

Gene Therapy for Bone Repair Using Human Cells: Superior Osteogenic Potential of Bone Morphogenetic Protein 2-Transduced Mesenchymal Stem Cells Derived from Adipose Tissue Compared to Bone Marrow.

Ex vivo regional gene therapy strategies using animal mesenchymal stem cells genetically modified to overexpress osteoinductive growth factors have been successfully used in a variety of animal models to induce both heterotopic and orthotopic bone formation. However, in order to adapt regional gene therapy for clinical applications, it is essential to assess the osteogenic capacity of transduced human cells and choose the cell type that demonstrates the best clinical potential. Bone-marrow stem cells (BMSC) and adipose-derived stem cells (ASC) were selected in this study for in vitro evaluation, before and after transduction with a lentiviral two-step transcriptional amplification system (TSTA) overexpressing bone morphogenetic protein 2 (BMP-2; LV-TSTA-BMP-2) or green fluorescent protein (GFP; LV-TSTA-GFP). Cell growth, transduction efficiency, BMP-2 production, and osteogenic capacity were assessed. The study demonstrated that BMSC were characterized by a slower cell growth compared to ASC. Fluorescence-activated cell sorting analysis of GFP-transduced cells confirmed successful transduction with the vector and revealed an overall higher but not statistically significant transduction efficiency in ASC versus BMSC (90.2 ± 4.06% vs. 80.4 ± 8.51%, respectively; p = 0.146). Enzyme-linked immunosorbent assay confirmed abundant BMP-2 production by both cell types transduced with LV-TSTA-BMP-2, with BMP-2 production being significantly higher in ASC versus BMSC (239.5 ± 116.55 ng vs. 70.86 ± 24.7 ng; p = 0.001). Quantitative analysis of extracellular deposition of calcium (Alizarin red) and alkaline phosphatase activity showed that BMP-2-transduced cells had a higher osteogenic differentiation capacity compared to non-transduced cells. When comparing the two cell types, ASC/LV-TSTA-BMP-2 demonstrated a significantly higher mineralization potential compared to BMSC/LV-TSTA-BMP-2 7 days post transduction (p = 0.014). In conclusion, this study demonstrates that transduction with LV-TSTA-BMP-2 can significantly enhance the osteogenic potential of both human BMSC and ASC. BMP-2-treated ASC exhibited higher BMP-2 production and greater osteogenic differentiation capacity compared to BMP-2-treated BMSC. These results, along with the fact that liposuction is an easy procedure with lower donor-site morbidity compared to BM aspiration, indicate that adipose tissue might be a preferable source of MSCs to develop a regional gene therapy approach to treat difficult bone-repair scenarios.

Orthopedic Surgery Applicants: What They Want in an Interview and How They Are Influenced by Post-Interview Contact.

OBJECTIVES: Common strategies for orthopedic residency programs to attract competitive applicants include optimizing the interview day and contacting favorably ranked applicants postinterview. The purpose of this work was to determine (1) applicants' perspectives on the ideal interview day, (2) how frequently applicants are contacted postinterview, and (3) the influence of this contact on rank order lists (ROL). DESIGN: Prospective Comparative Survey SETTING: Mayo Clinic Department of Orthopedic Surgery, Rochester, MN, USA PARTICIPANTS: A survey was completed by 312 successfully matched orthopedic surgery residency applicants following the 2015 match regarding their views of the ideal interview day, components they valued most, post-interview contact, and how that contact influenced their ROL. RESULTS: Applicants stated they preferred interviews that lasted 15 (55%) minutes, a mean of 1.7 (range: 1-5) interviewers present per interview, 5 total interviews (range: 1-10) in a day, an interview with residents (96%), and interviews days lasting only a half day (88%). The majority (94%) desire a social event attended by only residents (54%) or staff and residents (46%). Few wanted an assessment of surgical skills (36%) or orthopedic knowledge (23%). The interview day was rated very valuable in determining their ROL (4.4 out of 5.0). Applicants told a mean of 1.7 (range: 0-11) programs they were "ranking the program highly" and 0.8 (range: 0-5) programs they were "going to rank them #1." Of the 116 (40%) applicants contacted by programs following interviews, 24 (21%) moved programs higher and 3 (3%) moved programs lower on their ROL. CONCLUSIONS: Orthopedic Surgery applicants have clear preferences for what they consider to be the ideal interview day and many alter their ROL following post-interview contact. These data may be beneficial to programs looking to optimize the interview experience for applicants.

The Cost of Getting Into Orthopedic Residency: Analysis of Applicant Demographics, Expenditures, and the Value of Away Rotations.

OBJECTIVES: Little is known about the demographics and expenditures of applicants attempting to match into the competitive field of orthopedic surgery. In attempt to better inform potential applicants, the purposes of this work are to (1) better understand the demographics of successfully matched applicants, (2) determine the monetary cost of applying, and (3) assess the value of away rotations for improving chances of a successful match. DESIGN: Prospective comparative survey. SETTING: Mayo Clinic Department of Orthopedic Surgery, Rochester, MN. PARTICIPANTS: A week following the 2015 Orthopedic Surgery Residency Match, a survey was sent to 1,091. The survey focused on applicant demographics, number of programs applied to, cost of applying, and the value of away rotations. RESULTS: A total of 408 applicants completed the survey (response rate = 37%). Of these, 312 (76%) matched and 96 (24%) did not match into a US Orthopedic Surgery Residency. Of the matched applicants, 300 (96%) were from US allopathic medical schools, 9 (3%) US Osteopathic Schools, and 3 (1%) were international graduates. Males comprised 84% of these applicants whereas 16% were female. The mean number of programs applied to was 71 (range: 20-140). On average, applicants were offered 16 interviews (range: 1-53) and they attended 11 (range: 0-12). Completing a rotation at a program increased an applicant׳s chances of matching into that program by a factor of 1.5 (60% vs 40%). Of the applicants who matched, most applicants matched to an orthopedic residency in the same region where the applicant attended medical school (58%). The average cost of the application was $1,664 (range: $100-$5,000) whereas the cost of interviews (travel, food, etc.) was $3,656 (range: $15-$20,000). Total expenditures ranged from $450 to $25,000 (mean = $5,415). Over 8% of matched applicants spent >$10,000. CONCLUSIONS: Gaining acceptance into orthopedic surgery residency remains a very competitive process. Away rotations appear to correlate strongly with match status; however, the process remains quite expensive for applicants.

Effect of proximal femoral bone support on the fixation of a press-fit noncemented total hip replacement femoral component.

PURPOSE: Proximal femoral bone loss is a common challenge in revision hip arthroplasty. In this study, in-vitro fixation of a non-cemented, rectangular, dual-tapered, press-fit femoral component designed to achieve metadiaphyseal fixation was analyzed using an accelerated proximal femoral bone loss model to assess the potential use in revision cases. METHODS: The press-fit AlloclassicTM femoral stem was implanted in ten cadaveric femurs and tested under cyclic biomechanical loading in an intact state, and then again after sequential proximal femoral bone resections, simulating increasing amounts of bone deficiency. Anterior-posterior and medial-lateral interface motions were measured at the distal stem tip throughout loading. 
 RESULTS: Three specimens remained stable throughout testing, with initial and peak per-cycle motions of less than 50 µm. Six specimens were destabilized under loading with higher per-cycle motions, specifically at the distal stem tip during peak loading in the anterior-posterior direction, with motions of 78±69 µm, compared to 12±9 µm in the stable specimens (P<.05). Total migration of the destabilized specimens was also significantly higher, specifically at the proximal stem tip in the medial-lateral direction, with migrations of 101±34 µm (P<.05) and at the distal stem tip in the anterior-posterior direction, with migrations of 155±179 µm (P<.05), compared to 33±12 µm and 13±11 µm for the stable specimens. CONCLUSION: The results indicate that when strong initial fixation is achieved, long-term success is possible given substantial proximal femoral bone loss.