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Background: Total joint arthroplasty (TJA) is one of the most common procedures performed in the United States. Outcomes of this elective procedure may be improved via preoperative optimization of modifiable risk factors. Purposes: We sought to summarize the literature on the clinical implications of preoperative risk factors in TJA and to develop recommendations regarding preoperative optimization of these risk factors. Methods: We searched PubMed in August 2019 with an update in September 2020 for English-language, peer-reviewed publications assessing the influence on outcomes in total hip and knee replacement of 7 preoperative risk factors—obesity, malnutrition, hypoalbuminemia, diabetes, anemia, smoking, and opioid use—and recommendations to mitigate them. Results: Sixty-nine studies were identified, including 3 randomized controlled trials, 8 prospective cohort studies, 42 retrospective studies, 6 systematic reviews, 3 narrative reviews, and 7 consensus guidelines. These studies described worse outcomes associated with these 7 risk factors, including increased rates of in-hospital complications, transfusions, periprosthetic joint infections, revisions, and deaths. Recommendations for strategies to screen and address these risk factors are provided. Conclusions: Risk factors can be optimized, with evidence suggesting the following thresholds prior to surgery: a body mass index 2, serum albumin ≥3.5 g/dL, hemoglobin A1C ≤7.5%, hemoglobin >12.0 g/dL in women and >13.0 g/dL in men, and smoking cessation and ≥50% decrease in opioid use by 4 weeks prior to surgery. Surgery should be delayed until these risk factors are adequately optimized.

Postoperative urinary retention (POUR) after total knee arthroplasty (TKA) may cause urologic injury and delay patient discharge. This study measures the incidence of POUR and identifies predictive risk factors.Two-hundred seventy-one consecutive patients undergoing primary unilateral TKA were prospectively enrolled. Bladder scans were performed in the postanesthesia care unit (PACU) and every four hours thereafter. POUR was defined as400cc with inability to void and was treated with catheterization. Patient demographics, urologic history, operative data, perioperative medications, and bladder scanner volumes were investigated with the univariate and multivariate logistic regression analysis.Fifty-five patients (20%) developed POUR. Compared with non-POUR patients, PACU bladder scan volumes were greater in patients who developed POUR (344cc vs 120cc, P.001). POUR patients had lower BMI (27.8 vs 29.4, P = .03), longer operative duration (83.9 vs 76.0 minutes, P = .002), and lower ASA scores (2.2 vs 2.4, P = .02). Total intravenous fluid was equivalent between groups (1134cc vs 1185cc, P = .41). POUR patients received less narcotics measured by morphine milligram equivalents (16.1 vs 23.9, P.001). Fifteen variables including spinal type (bupivacaine and ropivacaine) and paralytic use were not predictive of POUR. Potentially predictive variables included anesthetic types administered (spinal, general, regional, and combination) and perioperative administration of nonsteroidal anti-inflammatory drugs (NSAIDs), glycopyrrolate, and muscle relaxants. The multivariate analysis showed that NSAIDs (P = .05) and glycopyrrolate (P = .04) were significant predictors.A significant percentage of patients develop POUR after TKA. Select patient demographics and PACU bladder scanning may identify those at risk. Appropriate pain control and judicious use of perioperative NSAIDs and glycopyrrolate may help minimize the risk of POUR.

Background Patients with a preoperative varus deformity >8 degrees are at increased risk of aseptic loosening after total knee arthroplasty. This study analyzes the effect of a tibial stem on the rate of aseptic loosening in patients with a severe preoperative varus deformity. Methods Patients with a preoperative varus deformity of >8 degrees and 2-year minimum follow-up with a stemmed tibial component (n = 67) were matched 1:2 to patients with a similar preoperative varus deformity with a standard tibial component (n = 134). Radiolucent lines were measured on the tibia at 6 weeks, 1 year, and 2 years postoperatively using the Knee Society Radiographic Evaluation System. Failure was defined as revision due to aseptic loosening of the tibial component. Outcomes were evaluated using Student’s t-tests and log-rank tests. Results Patients with tibial stems had greater preoperative deformity (12.9 vs 11.3 degrees, P = .004). There was no difference in postoperative alignment (1.7 vs 2.1 degrees varus, P = .25) or tibial component angle (1.8 vs 2.1 degrees varus, P = .33). Patients with stems were more likely to have more constraint (44.8% vs 1.5%, P 2 mm was observed in 17.6% (23/134) vs 5.97% (4/67) of patients in the stem group (P = .03). Rates of aseptic loosening were lower in the stem group (0% vs 5.15%, P = .05). Conclusion Despite worse preoperative deformity and higher utilization of constraint, tibial stem use in patients with severe preoperative varus deformity resulted in lower rates of aseptic loosening. Prophylactic use of stems in these patients may help increase implant survival.

Although the effect of tourniquet use during total knee arthroplasty (TKA) on functional outcomes is controversial, there are little data examining cement penetration and implant stability. This study examines the effect of tourniquet use on cement penetration and radiolucent line (RLL) progression.Patients undergoing primary total knee arthroplasty with a single surgeon, implant, and cement with minimum 5-year follow-up were retrospectively reviewed. Tourniquet use was defined as 30 minutes minimum, while no tourniquet was 0 minutes. Patients were 1:1 matched (n = 61 per group) by age (±5), gender, body mass index (±5), and follow-up (±2 years). Cement penetration and RLL were measured on the tibia at 6 weeks, and RLL at 1, 2, and 5 years postoperatively using the Knee Society Radiographic Evaluation System.Cement penetration was significantly increased in the tourniquet group in anterior-posterior zones 1 (2.16 vs 1.03 mm, P.0005), 2 (2.23 vs 1.51 mm, P.0005), and 5 (8.56 vs 6.3 mm, P = .009), and lateral zones 1 (2.89 vs 2.17 mm, P.0005), 2 (2.86 vs 2.12 mm, P.0005), 3P (3.99 vs 3.5 mm, P = .039), and 5 (8.18 vs 5.93 mm, P = .006). Cumulative cement penetration averaged 34.48 vs 43.33 mm in the tourniquet group (P.005). Progression of RLL2 mm was observed in 27.8% (17/61) vs 11.4% (7/61) of patients in the tourniquet group (P.005). There were 2 failures for aseptic tibial loosening in the no tourniquet group.Tourniquet use improves cement penetration and reduces RLL progression. Dryer surfaces during cementation may improve penetration, resulting in superior initial fixation strength and potentially reducing the long-term risk of aseptic loosening.

Aims Cross-table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). The CTL measurements may differ by > 10° from CT scan measurements but the reasons for this discrepancy are poorly understood. Anteversion measurements from CTL radiographs and CT scans are compared to identify spinopelvic parameters predictive of inaccuracy. Methods THA patients (n = 47; 27 males, 20 females; mean age 62.9 years (SD 6.95)) with preoperative spinopelvic mobility, radiological analysis, and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on postoperative CTL radiographs and CT scans using 3D reconstructions of the pelvis. Two cohorts were identified based on a CTL-CT error of ≥ 10° (n = 11) or < 10° (n = 36). Spinopelvic mobility parameters were compared using independent-samples t-tests. Correlation between error and mobility parameters were assessed with Pearson’s coefficient. Results Patients with CTL error > 10° (10° to 14°) had stiffer lumbar spines with less mean lumbar flexion (38.9°(SD 11.6°) vs 47.4° (SD 13.1°); p = 0.030), different sagittal balance measured by pelvic incidence-lumbar lordosis mismatch (5.9° (SD 18.8°) vs -1.7° (SD 9.8°); p = 0.042), more pelvic extension when seated (pelvic tilt -9.7° (SD 14.1°) vs -2.2° (SD 13.2°); p = 0.050), and greater change in pelvic tilt between supine and seated positions (12.6° (SD 12.1°) vs 4.7° (SD 12.5°); p = 0.036). The CTL measurement error showed a positive correlation with increased CTL anteversion ( r = 0.5; p = 0.001), standing lordosis ( r = 0.23; p = 0.050), seated lordosis ( r = 0.4; p = 0.009), and pelvic tilt change between supine and step-up positions ( r = 0.34; p = 0.010). Conclusion Differences in spinopelvic mobility may explain the variability of acetabular anteversion measurements made on CTL radiographs. Patients with stiff spines and increased compensatory pelvic movement have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with lumbar stiffness, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan. Cite this article: Bone Joint J 2021;103-B(7 Supple B):59–65.

Aims We aimed to examine the long-term mechanical survivorship, describe the modes of all-cause failure, and identify risk factors for mechanical failure of all-polyethylene tibial components in endoprosthetic reconstruction. Methods This is a retrospective database review of consecutive endoprosthetic reconstructions performed for oncological indications between 1980 and 2019. Patients with all-polyethylene tibial components were isolated and analyzed for revision for mechanical failure. Outcomes included survival of the all-polyethylene tibial component, revision surgery categorized according to the Henderson Failure Mode Classification, and complications and functional outcome, as assessed by the Musculoskeletal Tumor Society (MSTS) score at the final follow-up. Results A total of 278 patients were identified with 289 all-polyethylene tibial components. Mechanical survival was 98.4%, 91.1%, and 85.2% at five, ten and 15 years, respectively. A total of 15 mechanical failures were identified at the final follow-up. Of the 13 all-polyethylene tibial components used for revision of a previous tibial component, five (38.5%) failed mechanically. Younger patients (< 18 years vs > 18 years; p = 0.005) and those used as revision components (p < 0.001) had significantly increased rates of failure. Multivariate logistic regression modelling showed revision status to be a positive risk factor for failure (odds ratio (OR) 19.498, 95% confidence interval (CI) 4.598 to 82.676) and increasing age was a negative risk factor for failure (OR 0.927, 95% CI 0.872 to 0.987). Age-stratified risk analysis showed that age > 24 years was no longer a statistically significant risk factor for failure. The final mean MSTS score for all patients was 89% (8.5% to 100.0%). Conclusion The long-term mechanical survivorship of all-polyethylene tibial components when used for tumour endoprostheses was excellent. Tumour surgeons should consider using these components for their durability and the secondary benefits of reduced cost and ease of removal and revision. However, caution should be taken when using all-polyethylene tibial components in the revision setting as a significantly higher rate of mechanical failure was seen in this group of patients. Cite this article: Bone Joint J. 2020;102-B(2):170–176

Implant related infections are the most common cause of joint arthroplasty failure, requiring revision surgeries and a new implant, resulting in a cost of $8.6 billion annually. To address this problem, we created a class of coating technology that is applied in the operating room, in a procedure that takes less than 10 min, and can incorporate any desired antibiotic. Our coating technology uses an in situ coupling reaction of branched poly(ethylene glycol) and poly(allyl mercaptan) (PEG-PAM) polymers to generate an amphiphilic polymeric coating. We show in vivo efficacy in preventing implant infection in both post-arthroplasty infection and post-spinal surgery infection mouse models. Our technology displays efficacy with or without systemic antibiotics, the standard of care. Our coating technology is applied in a clinically relevant time frame, does not require modification of implant manufacturing process, and does not change the implant shelf life., Implant infection is the most common mode of joint replacement failure with serious complications. Here, the authors report on the in vivo application of a prophylactic coating technology that can incorporate a range of antibiotics and be applied in the operating room prior to implantation.

INTRODUCTION While the number of total hip arthroplasties (THAs) performed increases, so is the number of postoperative readmissions, resulting in costly episodes of care that may disproportionately affect certain hospitals. This study examines the rates of readmission of patients to the same hospital at which they underwent index THA, compared with readmission to a different hospital. METHODS Data for all hospital discharges from 1995 to 2010 were obtained from the California Office of Statewide Health Planning and Development database. Patient outcomes, readmission data, demographic information, hospital teaching status, and location were analyzed. Regression modeling was used to evaluate the effect of hospital teaching status, location, and individual complications on the risk of readmission to the same hospital as opposed to a different hospital following the index procedure. RESULTS The overall postoperative readmission rate for specific defined complications or all-cause 30-day readmissions was 3.92%, with 75.17% readmitted to the same hospital. Following index THA at a nonacademic or academic hospital, 95.9% and 84.6% of patients were readmitted to the same type of hospital, respectively. Patients who had their index procedure at an academic hospital had lower odds for readmission to the same hospital (odds ratio, 0.734; P < 0.0001) compared with nonacademic centers. Hospitals in midsize towns had higher odds of readmission to the same hospital (odds ratio, 1.735; P = 0.0012) compared with those in large metropolitan areas. DISCUSSION Although more than 75% of patients with unplanned readmissions went to the same hospital as their index THA, academic and larger metropolitan hospitals had higher odds of postoperative readmissions to a different hospital.

Implant-associated infections are challenging to diagnose and treat. Fluorescent probes have been heralded as a technologic advancement that can improve our ability to non-invasively identify infecting organisms, as well as guide the inexact procedure of surgical debridement. This study’s purpose was to compare two fluorescent probes for their ability to localize Staphylococcus aureus biofilm infections on spinal implants utilizing noninvasive optical imaging, then assessing the broader applicability of the more successful probe in other infection animal models. This was followed by real-time, fluorescence image-guided surgery to facilitate debridement of infected tissue. The two probe candidates, a labelled antibiotic that targets peptidoglycan (Vanco-800CW), and the other, a labelled antibody targeting the immunodominant Staphylococcal antigen A (1D9-680), were injected into mice with spine implant infections. Mice were then imaged noninvasively with near infrared fluorescent imaging at wavelengths corresponding to the two probe candidates. Both probes localized to the infection, with the 1D9-680 probe showing greater fidelity over time. The 1D9-680 probe was then tested in mouse models of shoulder implant and allograft infection, demonstrating its broader applicability. Finally, an image-guided surgery system which superimposes fluorescent signals over analog, real-time, tissue images was employed to facilitate debridement of fluorescent-labelled bacteria.

Extremity reconstruction surgery is increasingly performed rather than amputation for patients with large-segment pathologic bone loss. Debate persists as to the optimal void filler for this “limb salvage” surgery, whether metal or allograft bone. Clinicians focus on optimizing important functional gains for patients, and the risk of devastating implant infection has been thought to be similar regardless of implant material. Recent insights into infection pathophysiology are challenging this equipoise, however, with both basic science data suggesting a novel mechanism of infection of Staphylococcus aureus (the most common infecting agent) into the host lacunar–canaliculi network, and also clinical data revealing a higher rate of infection of allograft over metal. The current translational study was therefore developed to bridge the gap between these insights in a longitudinal murine model of infection of allograft bone and metal. Real-time Staphylococci infection characteristics were quantified in cortical bone vs metal, and both microarchitecture of host implant and presence of host immune response were assessed. An orders-of-magnitude higher bacterial burden was established in cortical allograft bone over both metal and cancellous bone. The establishment of immune-evading microabscesses was confirmed in both cortical allograft haversian canal and the submicron canaliculi network in an additional model of mouse femur bone infection. These study results reveal a mechanism by which Staphylococci evasion of host immunity is possible, contributing to elevated risks of infection in cortical bone. The presence of this local infection reservoir imparts massive clinical implications that may alter the current paradigm of osteomyelitis and bulk allograft infection treatment.

Purpose To critically evaluate the quality, accuracy, and readability of readily available Internet patient resources for platelet-rich plasma (PRP) as a treatment modality for musculoskeletal injuries. Methods Using the 3 most commonly used Internet search engines (Google, Bing, Yahoo), the search term "platelet rich plasma" was entered, and the first 50 websites from each search were reviewed. The website's affiliation was identified. Quality was evaluated using 25-point criteria based on guidelines published by the American Academy of Orthopaedic Surgeons, and accuracy was assessed with a previously described 12-point grading system by 3 reviewers independently. Readability was evaluated using the Flesch-Kincaid (FK) grade score. Results A total of 46 unique websites were identified and evaluated. The average quality and accuracy was 9.4 ± 3.4 (maximum 25) and 7.9 ± 2.3 (maximum 12), respectively. The average FK grade level was 12.6 ± 2.4, which is several grades higher than the recommended eighth-grade level for patient education material. Ninety-one percent (42/46) of websites were authored by physicians, and 9% (4/46) contained commercial bias. Mean quality was significantly greater in websites authored by health care providers (9.8 ± 3.1 vs 5.9 ± 4.7, P = .029) and in websites without commercial bias (9.9 ± 3.1 vs 4.5 ± 3.2, P = .002). Mean accuracy was significantly lower in websites authored by health care providers (7.6 ± 2.2 vs 11.0 ± 1.2, P = .004). Only 24% (11/46) reported that PRP remains an investigational treatment. Conclusions The accuracy and quality of online patient resources for PRP are poor, and the information overestimates the reading ability of the general population. Websites authored by health care providers had higher quality but lower accuracy. Additionally, the majority of websites do not identify PRP as an experimental treatment, which may fail to provide appropriate patient understanding and expectations. Clinical Relevance Physicians should educate patients that many online patient resources have poor quality and accuracy and can be difficult to read.

Author(s): Hegde, Vishal; Park, Howard Y; Dworsky, Erik; Zoller, Stephen D; Xi, Weixian; Johansen, Daniel O; Loftin, Amanda H; Hamad, Christopher D; Segura, Tatiana; Bernthal, Nicholas M | Abstract: Study designA controlled, interventional animal study.ObjectiveSpinal implant infection (SII) is a devastating complication. The objective of this study was to evaluate the efficacy of a novel implant coating that has both a passive antibiotic elution and an active-release mechanism triggered in the presence of bacteria, using an in vivo mouse model of SII.Summary of background dataCurrent methods to minimize the frequency of SII include local antibiotic therapy (vancomycin powder), betadine irrigation, silver nanoparticles, and passive release from antibiotic-loaded poly(methyl methacrylate) cement beads, all of which have notable weaknesses. A novel implant coating has been developed to address some of these limitations but has not been tested in the environment of a SII.MethodsA biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics. The in vivo performance of this coating was tested in the delivery of either vancomycin or tigecycline in a previously established mouse model of SII. Noninvasive bioluminescence imaging was used to quantify the bacterial burden, and implant sonication was used to determine bacterial colony-forming units (CFUs) from the implant and surrounding bone and soft tissue.ResultsThe PEG-PPS-vancomycin coating significantly lowered the infection burden from postoperative day 3 onwards (P l 0.05), whereas PEG-PPS-tigecycline only decreased the infection on postoperative day 5 to 10 (P l 0.05). CFUs were lower on PEG-PPS-vancomycin pins than PEG-PPS-tigecycline and PEG-PPS pins alone on both the implants (2.4 × 10, 8.5 × 10, and 1.0 × 10 CFUs, respectively) and surrounding bone and soft tissue (1.3 × 10, 4.8 × 10, and 5.4 × 10 CFUs, respectively) (P l 0.05).ConclusionThe biodegradable PEG-PPS coating demonstrates promise in decreasing bacterial burden and preventing SII. The vancomycin coating outperformed the tigecycline coating in this model compared to prior work in arthroplasty models, highlighting the uniqueness of the paraspinal infection microenvironment.Level of evidenceN/A.

Post-operative spine infections are a challenge, as hardware must often be retained to prevent destabilization of the spine, and bacteria form biofilm on implants, rendering them inaccessible to antibiotic therapy, and immune cells. A model of posterior-approach spinal surgery was created in which a stainless steel k-wire was transfixed into the L4 spinous process of 12-week-old C57BL/six mice. Mice were then randomized to receive either one of three concentrations (1 × 102 , 1 × 103 , and 1 × 104 colony forming units (CFU)) of a bioluminescent strain of Staphylococcus aureus or normal saline at surgery. The mice were then longitudinally imaged for bacterial bioluminescence to quantify infection. The 1 × 102 CFU group had a decrease in signal down to control levels by POD 25, while the 1 × 103 and 1 × 104 CFU groups maintained a 10-fold higher signal through POD 35. Bacteria were then harvested from the pin and surrounding tissue for confirmatory CFU counts. All mice in the 1 × 104 CFU group experienced wound breakdown, while no mice in the other groups had this complication. Once an optimal bacterial concentration was determined, mice expressing enhanced green fluorescent protein in their myeloid cells (Lys-EGFP) were utilized to contemporaneously quantify bacterial burden, and immune response. Neutrophil fluorescence peaked for both groups on POD 3, and then declined. The infected group continued to have a response above the control group through POD 35. This study, establishes a noninvasive in vivo mouse model of spine implant infection that can quantify bacterial burden and host inflammation longitudinally in real time without requiring animal sacrifice. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:193-199, 2017.

Introduction. Treatment of open fractures routinely involves multiple surgeries and delayed definitive fracture fixation because of concern for infection. If implants were made less susceptible to infection, a one-stage procedure with intramedullary nailing would be more feasible, which would reduce morbidity and improve outcomes. Methods. In this study, a novel open fracture mouse model was developed using Staphylococcus aureus (S. aureus) and single-stage intramedullary fixation. The model was used to evaluate whether implants coated with a novel “smart” polymer coating containing vancomycin or tigecycline would be colonized by bacteria in an open fracture model infected with S. aureus. In vivo bioluminescence, ex vivo CFUs, and X-ray images were evaluated over a 42-day postoperative period. Results. We found evidence of a markedly decreased bacterial burden with the local release of vancomycin and tigecycline from the PEG-PPS polymer compared to polymer alone. Vancomycin was released in a controlled fashion and maintained local drug concentrations above the minimum inhibition concentration for S. aureus for greater than 7 days postoperatively. Bacteria were reduced 139-fold from implants containing vancomycin and undetected from the bone and soft tissue. Tigecycline coatings led to a 5991-fold reduction in bacteria isolated from bone and soft tissue and 15-fold reduction on the implants compared to polymer alone. Antibiotic coatings also prevented osteomyelitis and implant loosening as observed on X-ray. Conclusion. Vancomycin and tigecycline can be encapsulated in a polymer coating and released over time to maintain therapeutic levels during the perioperative period. Our results suggest that antibiotic coatings can be used to prevent implant infection and osteomyelitis in the setting of open fracture. This novel open fracture mouse model can be used as a powerful in vivo preclinical tool to evaluate and optimize the treatment of open fractures before further studies in humans.

IntroductionAlthough a variety of agencies have attempted to evaluate the academic achievements of orthopaedic surgery academic centers, most use opaque criteria that are difficult to interpret and do not provide clear targets for improvement. This study leverages a weighted algorithm using objective measurements that has been linked to academic achievement to attempt to provide a comprehensive assessment of scholarly accomplishment for orthopaedic surgery academic centers.MethodsWe examined full-time faculty at 138 US orthopaedic surgery academic centers; part-time or volunteer faculty were excluded. Five metrics of academic achievement were assessed: National Institutes of Health funding (2013), number of publications, Hirschberg-index (ie, a metric of impact of publications), leadership positions held in orthopaedic surgery societies, and editorial board positions of top orthopaedic and subspecialty journals. Academic programs were given a score for every category, and the algorithm was used to calculate an overall score of academic achievement for each program.ResultsThe five most academically productive programs were Washington University in St. Louis, Hospital for Special Surgery, Mayo Clinic, University of Pennsylvania, and Thomas Jefferson University.ConclusionThis algorithm may provide faculty with an assessment tool that can establish benchmarks to help focus efforts toward increasing the academic productivity of their respective programs.

The purpose of this study was to determine the relative incidence of postoperative complications in 25-hydroxyvitamin D (25D)-deficient and -sufficient patients undergoing total knee arthroplasty (TKA). Patients who were either serum 25D deficient (25D International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes. Risk-adjusted odds ratios (ORs) were calculated using multivariate logistic regression with age, sex, and Charlson Comorbidity Index as covariates. In total, 868 of 6593 patients who underwent TKA from 2007 to 2016 were 25D deficient, corresponding to a 13.2% prevalence rate. On adjustment for age, sex, and Charlson Comorbidity Index, 25D-deficient patients had a higher incidence of postoperative stiffness requiring manipulation under anesthesia (OR, 1.69; 95% confidence interval [CI], 1.39–2.04; P P =.001), and prosthesis explantation (OR, 2.97; 95% CI, 2.04–4.31; P P P P =.006). Thus, serum 25D levels below 20 ng/mL are associated with a higher incidence of postoperative complications and may be a perioperative modifiable risk factor in TKA. [ Orthopedics . 2018; 41(4):e489–e495.]

Author(s): Park, Howard Y; Zoller, Stephen D; Sheppard, William L; Hegde, Vishal; Smith, Ryan A; Borthwell, Rachel M; Clarkson, Samuel J; Hamad, Christopher D; Proal, Joshua D; Bernthal, Nicholas M | Abstract: BackgroundAccording to the American Academy of Orthopaedic Surgeons (AAOS) Standards of Professionalism, the responsible testimony of expert witnesses in orthopaedic surgery malpractice lawsuits is important to the public interest. However, these expert witnesses are recruited and compensated without established standards, and their testimony can potentially sway court opinion, with substantial consequences. The objective of this study was to characterize defense and plaintiff expert orthopaedic surgeon witnesses in orthopaedic surgery malpractice litigation.MethodsUtilizing the WestlawNext legal database, defense and plaintiff expert witnesses involved in orthopaedic surgery malpractice lawsuits from 2013 to 2017 were identified. Each witness's subspecialty, mean years of experience, involvement in academic or private practice, fellowship training, and scholarly impact, as measured by the Hirsch index (h-index), were determined through a query of professional profiles, the Scopus database, and a PubMed search. Statistical comparisons were made for each parameter among defense and plaintiff expert witnesses.ResultsBetween 2013 and 2017, 306 expert medical witnesses for orthopaedic cases were identified; 174 (56.9%) testified on behalf of the plaintiff, and 132 (43.1%) testified on behalf of the defense. Orthopaedic surgeons who identified themselves as general orthopaedists comprised the largest share of expert witnesses on both the plaintiff (n = 61) and defense (n = 25) sides. The plaintiff witnesses averaged 36 years of experience versus 31 years for the defense witnesses (p l 0.001); 26% of the plaintiff witnesses held an academic position versus 43% of the defense witnesses (p = 0.013). Defense witnesses exhibited a higher proportion of fellowship training in comparison to plaintiff expert witnesses (80.5% versus 64.5%, respectively, p = 0.003). The h-index for the plaintiff group was 6.6 versus 9.1 for the defense group (p = 0.04). Two witnesses testified for both the plaintiff and defense sides.ConclusionsDefense expert witnesses held higher rates of academic appointments and exhibited greater scholarly impact than their plaintiff counterparts, with both sides averaging g30 years of experience. These data collectively show that there are differences in characteristics between plaintiff and defense witnesses. Additional study is needed to illuminate the etiology of these differences.

Author(s): Hegde, Vishal; Burke, Zachary DC; Park, Howard Y; Zoller, Stephen D; Johansen, Daniel; Kelley, Benjamin V; Levine, Ben; Motamedi, Kambiz; Federman, Noah C; Seeger, Leanne L; Nelson, Scott D; Bernthal, Nicholas M | Abstract: BACKGROUND:Although there is widespread acceptance of core needle biopsy (CNB) for diagnosing solid tumors, there is reluctance by some clinicians to use CNB for aneurysmal bone cysts (ABCs) as a result of concerns of safety (bleeding, nerve injury, fracture, readmission, or infection) and reliability, particularly to rule out malignant diagnoses like telangiectatic osteosarcoma. This is especially true when CNB tissue is sent from an outside hospital, where the technique used to obtain the tissue may be spurious. QUESTIONS/PURPOSES:(1) Is CNB effective (provided adequate information to indicate appropriate surgical treatment without further open biopsy) as an initial diagnostic test for ABC? (2) Is CNB accurate (pathology consistent with the subsequent definitive surgical pathologic diagnosis) in differentiating between benign lesions such as primary or secondary ABCs and malignant radiolucent lesions such as telangiectatic osteosarcoma? (3) What are the complications of CNB? (4) Is there any difference in the effectiveness or accuracy of CNB performed at outside institutions when compared with a referral center? METHODS:A retrospective study of our musculoskeletal tumor board pathology database (1990-2016) was performed using search criteria "aneurysmal bone cyst" or "telangiectatic osteosarcoma." Only patients undergoing a CNB who proceeded to definitive surgical resection with final pathology were included. Excluding outside CNBs, CNB was performed after presentation at a musculoskeletal tumor board as a result of atypical features on imaging or history concerning for malignancy. Outside CNB tissue was reviewed by our pathologists. If there was sufficient tissue for diagnosis, the patient proceeded to definitive surgery. If not, the patient underwent open biopsy. CNB diagnosis, open biopsy results, and open surgical resection pathology were reviewed. Complications, including bleeding, infection, nerve injury, readmission, or fracture, between the CNB and definitive open surgical procedure (mean 1.6 months) were documented. CNBs were considered "effective" if they yielded pathology considered sufficient to proceed with appropriate definitive surgery without additional open biopsy. CNBs were considered "accurate" if they were effective and yielded a pathologic diagnosis that matched the subsequent definitive surgical pathology. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of obtaining a malignant diagnosis using CNB were also calculated. RESULTS:A total of 81% (59 of 73) of CNBs were effective. Ninety-three percent (55 of 59) of CNBs were classified as accurate. Diagnostic CNBs had a sensitivity and specificity of 89% (eight of nine) and 100% (51 of 51), respectively. The PPV was 1.00 and the NPV was 0.82. There were no complications. With the numbers available, there was no difference in efficacy (90% [37 of 41 versus 14 of 15]; odds ratio, 0.97 [95% confidence interval {CI}, 0.41-2.27], p = 0.94) or accuracy (92% [34 of 37 versus 13 of 14]; odds ratio, 0.87 [95% CI, 0.08-9.16], p = 0.91) between CNBs performed in house and those referred from outside. CONCLUSIONS:These data suggest that CNBs are useful as an initial diagnostic test for ABC and telangiectatic osteosarcoma. Tissue from outside CNBs can be read reliably without repeat biopsy. If confirmed by other institutions, CNB may be considered a reasonable approach to the diagnosis of aggressive, radiolucent lesions of bone. LEVEL OF EVIDENCE:Level III, diagnostic study.

Antiosteoporotic medications are often used to concurrently treat a patient's fragility fractures and underlying osteoporosis. This review evaluates the existing literature from animal and clinical models to determine these drugs' effects on fracture healing. The data suggest that these medications may enhance bone healing, yet more thorough prospective studies are warranted. Pharmacologic agents that influence bone remodeling are an essential component of osteoporosis management. Because many patients are first diagnosed with osteoporosis when presenting with a fragility fracture, it is critical to understand how osteoporotic medications influence fracture healing. Vitamin D and its analogs are essential for the mineralization of the callus and may also play a role in callus formation and remodeling that enhances biomechanical strength. In animal models, antiresorptive medications, including bisphosphonates, denosumab, calcitonin, estrogen, and raloxifene, do not impede endochondral fracture healing but may delay repair due to impaired remodeling. Although bisphosphonates and denosumab delay callus remodeling, they increase callus volume and result in unaltered biomechanical properties. Calcitonin increases cartilage formation and callus maturation, resulting in improved biomechanical properties. Parathyroid hormone, an anabolic agent, has demonstrated promise in animal models, resulting in accelerated healing with increased callus volume and density, more rapid remodeling to mature bone, and improved biomechanical properties. Clinical data with parathyroid hormone have demonstrated enhanced healing in distal radius and pelvic fractures as well as postoperatively following spine surgery. Strontium ranelate, which may have both antiresorptive and anabolic properties, affects fracture healing differently in normal and osteoporotic bone. While there is no effect in normal bone, in osteoporotic bone, strontium ranelate increases callus bone formation, maturity, and mineralization; forms greater and denser trabeculae; and improves biomechanical properties. Further clinical studies with these medications are needed to fully understand their effects on fracture healing in order to simultaneously treat fragility fractures and underlying osteoporosis.

Background and Objective Cemented endoprosthetic reconstruction after resection of primary bone sarcomas has been a standard-of-care option for decades. With increased patient survival, the incidence of failed endoprostheses requiring revision surgery has increased. Revision of cemented endoprotheses by cementing into the existing cement mantle (CiC) is technically demanding. Methods This is a retrospective review of our endoprosthesis database of 512 consecutive cemented endoprosthetic reconstructions performed for oncologic diagnoses between 1980 and 2014. A total of 54 implants (mean patient age 32 years, range 13-81) were revised with a CiC technique. Outcomes evaluated were prosthesis survival, revision surgery categorized according to the Henderson Failure Mode Classification, complications, and functional scores. Results Fifteen-year Kaplan-Meier survival rate was 34% for initial revision and 39% for subsequent revision implants. Mean revised Musculoskeletal Tumor Society (MSTS) Score was 27 at latest follow-up. Infection rate was 2%, 9%, and 13% for primary endoprostheses, initial revisions, and subsequent revisions, respectively. Limb salvage rate was 87%. Conclusions At long-term follow up, endoprostheses revised with the CiC technique showed consistent 15-year survival from initial (34%) to subsequent (39%) revision. Despite a relatively high failure rate, these results are encouraging and demonstrate that this is a conservative, repeatable technique.

BackgroundDespite recent advances, infection remains the most common etiology of arthroplasty failure. Recent work suggests that 25-hydroxyvitamin D (25D) deficiency correlates with the frequency of periprosthetic joint infection (PJI). We endeavored to examine whether 25D3 deficiency leads to increased bacterial burden in vivo in an established mouse model of PJI and, if so, whether this effect can be reversed by preoperative 25D3 supplementation.MethodsMice (lys-EGFP) possessing fluorescent neutrophils were fed a vitamin D3-sufficient (n = 20) or deficient (n = 40) diet for 6 weeks. A group of 25D3-deficient mice (n = 20) were "rescued" with 1 intraperitoneal dose of 25D3 at 3 days before surgery. A stainless steel implant was inserted into the knee joint and the joint space was inoculated with bioluminescent Staphylococcus aureus (1 × 10 colony forming units [CFUs]). In vivo imaging was used to monitor bacterial burden and neutrophil infiltration. Blood was drawn to confirm 25D3 levels 3 days before surgery and on postoperative days (PODs) 0 and 14. Mice were killed at POD 21, and CFUs were quantified after culture. Myeloperoxidase (MPO) and β-N-acetylglucosaminidase (NAG) were assayed to look at neutrophil infiltration and activated tissue macrophage recruitment, respectively.ResultsSerum values confirmed 25D3 deficiency and repletion of the 25D3-rescued group. Bacterial bioluminescence and neutrophil fluorescence were significantly greater (p < 0.05) in the 25D3-deficient group. CFU counts from the joint tissue and implant were also significantly greater in this group (p < 0.05). Rescue treatment significantly decreased bacterial burden and neutrophil infiltration (p < 0.05). Compared with the 25D3-sufficient and 25D3-rescued groups, MPO activity was higher (p < 0.02) and NAG activity was lower (p < 0.03) in the 25D3-deficient group.ConclusionsThis study demonstrated in vivo in a mouse model of PJI that (1) 25D3 deficiency results in increased bacterial burden and neutrophil infiltration, and (2) this effect can be reversed with preoperative repletion of 25D3.Clinical relevanceConsidering that >65% of patients undergoing arthroplasty have insufficient or low levels of total 25D and that 25D levels can be replenished with ease using a U.S. Food and Drug Administration (FDA)-approved, oral 25D3 product, 25D deficiency may be an important modifiable risk factor in humans undergoing joint replacement.

Author(s): Hegde, Vishal; Johansen, Daniel; Park, Howard Y; Zoller, Stephen D; Hamad, Christopher; Bernthal, Nicholas M | Abstract: BackgroundThe Orthopaedic Research and Education Foundation (OREF) is the leading specialty-specific nongovernmental organization providing orthopaedic funding in the United States. As extramural research funding has become increasingly difficult to acquire, one mission of the OREF is to support investigators to generate data needed to secure larger extramural funding from agencies such as the National Institutes of Health (NIH). The objectives of this study were to evaluate the rate of translating OREF faculty-level grants into subsequent NIH funding and to determine if there are identifiable factors that increase the rate of converting an OREF grant into NIH funding.MethodsThis is a retrospective review of OREF grants awarded to full-time faculty orthopaedic surgeons between 1994 and 2014. Grants were analyzed on the basis of award type and were categorized as basic science, clinical, or epidemiological. Sex, individual scholarly productivity, and publication experience were evaluated. All awardees were assessed for subsequent NIH funding using the NIH RePORTER web site.ResultsOne hundred and twenty-six faculty-level OREF grants were awarded to 121 individuals. Twenty-seven OREF grant awardees (22%) received NIH funding at a mean of 6.3 years after OREF funding. Nineteen (46%) of 41 Career Development Grant winners later received NIH funding compared with 10 (12%) of 85 other award winners. OREF grants for basic science projects were awarded more often (58%) and were more than 4 times as likely to result in NIH funding than non-basic science projects (odds ratio, 4.70 [95% confidence interval, 1.66 to 13.33]; p = 0.0036). Faculty who later received NIH funding had higher scholarly productivity and publication experience (p l 0.05).ConclusionsThe OREF grant awardee conversion rate of 22% and, particularly, the 46% for Career Development Grant winners compares favorably with the overall NIH funding success rate (18% in 2014). Faculty-level OREF grants appear to achieve their purpose of identifying and supporting researchers who aim to secure subsequent federal funding.Clinical relevanceThe goal of this study is to examine how successful faculty who have obtained OREF grants have been in securing NIH funding later in their careers. Although subsequent accrual of NIH funding is not the only goal of OREF funding, it can be used as an important benchmark to assess the development of orthopaedic clinician-scientists.

To evaluate the efficacy of 3 commercially available systems: the Harvest SmartPReP 2 BMAC, Biomet BioCUE, and Arteriocyte Magellan systems. We compared the number and concentration of progenitor cells achieved both before and after centrifugation and the percentage of progenitor cells salvaged after centrifugation.Forty patients, mean age 47 ± 18 years (range: 18-92 years, 19 male/21 female) were prospectively consented for bilateral iliac crest aspiration. The first 20 aspirations compared the Harvest and Biomet systems, and based on those results, the second 20 compared the Harvest and Arteriocyte systems. One system was randomly assigned to each iliac crest. Each system's unique marrow acquisition process and centrifugation mechanism was followed. Samples for analysis were taken both immediately before the marrow was put into the centrifugation system (after acquisition), and after centrifugation. The number of progenitor cells in each sample was estimated by counting the connective tissue progenitors (CTPs).The Harvest system achieved a significantly greater number and concentration of CTPs both before and after centrifugation when compared to the Biomet system. There was no difference in the percent yield of CTPs after centrifugation. There was no significant difference in the number and concentration of CTPs between the Harvest and Arteriocyte systems before centrifugation, but the Harvest system had a significantly greater number and concentration of CTPs after centrifugation. The Harvest system also had a significantly higher percent yield of CTPs after centrifugation compared with the Arteriocyte system.The Harvest system resulted in a greater CTP number and concentration after centrifugation when compared with the Biomet and Arteriocyte systems and may thus provide increased osteogenic and chondrogenic capacity.

BACKGROUND CONTEXT Diagnosis and precise localization of spine infections are an elusive pursuit. Despite widespread technical advances, the current standard of magnetic resonance imaging lacks the precision to discern infection versus inflammation due to other causes. Nuclear medicine utilizing the metabolic positron emission tomography (PET) probe18F-fluorodeoxyglucose (18F-FDG) can identify inflammation, but it lacks specificity for bacterial infection. However, adjuncts compatible with PET/CT imaging have the potential to noninvasively increase the specificity for bacteria responsible for spine infections and guide surgeons with regard to the locale and extent of infection. PURPOSE The purpose of this study is to assess the diagnostic potential of utilizing PET/CT and 89-Zirconium (89Zr) labeled bacterial probes in noninvasive, accurate localization of spine implant infections. STUDY DESIGN/SETTING This is a basic science investigation utilizing a mouse model of spine infection. The spine implants are inoculated with bioluminescentStaphylococcus aureusfor longitudinal quantification of bacterial burden, and PET/CT signal intensity is quantified utilizing 18F-FDG and 89Zr-DFO-1D9 mAb intravenous injections. PATIENT SAMPLE Fifteen12-week-oldC57BL/6 wild type mice were utilized. OUTCOME MEASURES In vivobioluminescence and PET/CT signal intensity was quantified utilizing imaging software. Three-dimensional PET/CT images were utilized to localize signal intensities of interest. METHODS In accordance with an established mouse model of spine implant infection, a spinal implant was fixed into the spinous process of the L4 vertebra. Inoculation of the implant and wound bed was performed with bioluminescent S. Aureus. On postoperative day 7, 18F-FDG PET/CT imaging was completed in 11 infected and four sterile control mice. They were also injected intravenously via lateral tail vein with 68.6±1.6 μCi (∼14μgmAb) of89Zr-DFO-1D9 mAb. One week following89Zr-DFO-1D9 injection, mice underwent PET/CT to detect 89Zr-DFO-1D9 mAb signal intensities. RESULTS Bioluminescence imaging revealed signal emitted solely from the surgical bed of infected mice which matched that of historical infected controls – bioluminescence signals remained elevated over the duration of the experiment suggestive of sustained bacterial infection. PET-CT imaging with 18F-FDG probe revealed high signal intensity at the site of the spine implant with lower levels of signal within the gut, bladder, and heart. The 89Zr-DFO-1D9 mAb probe signal in the region of the implant was significantly higher in infected mice compared to sterile controls (2.72e9±1.19e9 versus 6.60E8±3.56E8 total radiant efficiency, respectively;p CONCLUSIONS TheS. aureusspecific89Zr-DFO-1D9 mAb probe was shown by PET/CT imaging to accurately detectinfections in-vivo. This study represents the first in-vivo investigation utilizing PET/CT with intravenous bacterial specific probes which may vastly improve the ability to accurately and noninvasively diagnose and localize spine infections.

BACKGROUND CONTEXT Bisphosphonates are commonly used in the orthopedic patient population to manage osteoporosis and other metabolic bone diseases. There is also increasing support for bisphosphonate use in the perioperative setting, to minimize osteolysis and bone loss. Additionally, bisphosphonates are known to affect the host immune system; however, their effect on implant infections, which are notoriously difficult to treat, remains largely unknown. PURPOSE The purpose of this study was to assess the effect of zoledronic acid (ZA) on spinal implant infection in our validated mouse model. METHODS Twenty-six 8-week-old C57BL/6 mice were included in the study. Twelve were treated with 250 ug/kg of ZA,12 with normal saline via retro-orbital injection on the day of surgery, and the remaining 2 were sterile controls. A stainless steel pin was then placed into the L4 spinous processes of all mice and site was inoculated with 1E+3 CFUs of bioluminescent Xen36 Staphylococcus aureus in experimental groups. Infection burden was monitored with in vivo bioluminescence imaging at pre-determined intervals. RESULTS Following an initial similar increase after surgery and inoculation, mice treated with ZA showed a decreased bacterial burden as compared to infected control group (p CONCLUSIONS The indications for ZA use continue to expand, and it is often used in the perioperative setting. In our validated mouse model of spine implant infection, ZA decreases bacterial burden as compared to controls. Further investigation is required to determine the effects of dosing, location of infection and to explore possible mechanisms by which ZA exerts this effect. These findings may suggest a further benefit to bisphosphonate use in the perioperative setting. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

With its continued successin improving bone mineral density and reducingthe incidence of some fractures associated withlow bone mass, longer-term data regardingbisphosphonate use have become available. Al-though described before the Food and DrugAdministration’s (FDA) approval and widespreadclinical use of bisphosphonates, an uncommonvariant of subtrochanteric and femoral shaft frac-tures thought to be associated with prolonged bi-sphosphonate therapy has captured the attentionof the osteoporosis community. These so-calledatypical femoral fractures occur after minimaltrauma and have a distinct configuration and ra-diographic appearance compared with typicalosteoporotic fractures. Although there is noevidence to suggest a cause-and-effect relation-ship, several studies have established an associa-tion between long-term bisphosphonate therapyandatypicalfemoralfractures.

Aneurysmal bone cysts (ABCs) are benign bone lesions arising predominantly in the pediatric population that can cause local pain, swelling, and pathologic fracture. Primary lesions, which constitute roughly two thirds of all ABCs, are thought to be neoplastic in nature, with one third of ABCs arising secondary to other tumors. Diagnosis is made with various imaging modalities, which exhibit characteristic features such as "fluid-fluid levels," although biopsy is critical, as telangiectatic osteosarcoma cannot be excluded based on imaging alone. Currently, the standard of care and most widely employed treatment is intralesional curettage. However, tumor recurrence with curettage alone is common and has driven some to propose a multitude of adjuvants with varying efficacy and risk profiles. Historically, therapies such as en bloc resection or radiation therapy were utilized as an alternative to decrease the recurrence rate, but these therapies imposed high morbidity. As a result, modern techniques now seek to simultaneously reduce morbidity and recurrence, the pursuit of which has produced preliminary study into minimally invasive percutaneous treatments and medical management.

Background: Postoperative infection is a devastating complication following arthroplasty. The goals of this study were to introduce a “smart” implant coating that combines passive elution of antibiotic with an active-release mechanism that “targets” bacteria, and to use an established in vivo mouse model of post-arthroplasty infection to longitudinally evaluate the efficacy of this polymer implant coating in decreasing bacterial burden. Methods: A novel, biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics both passively and actively. In vitro-release kinetics were studied using high-performance liquid chromatography (HPLC) quantification in conditions representing both the physiologic environment and the more oxidative, hyperinflammatory environment of periprosthetic infection. The in vivo efficacy of the PEG-PPS coating delivering vancomycin and tigecycline was tested using an established mouse model of post-arthroplasty infection. Noninvasive bioluminescence imaging was used to quantify the bacterial burden; radiography, to assess osseointegration and bone resorption; and implant sonication, for colony counts. Results: In vitro-release kinetics confirmed passive elution above the minimum inhibitory concentration (MIC). A rapid release of antibiotic was noted when challenged with an oxidative environment (p < 0.05), confirming a “smart” active-release mechanism. The PEG-PPS coating with tigecycline significantly lowered the infection burden on all days, whereas PEG-PPS-vancomycin decreased infection on postoperative day (POD) 1, 3, 5, and 7 (p < 0.05). A mean of 0, 9, and 2.6 × 102 colony-forming units (CFUs) grew on culture from the implants treated with tigecycline, vancomycin, and PEG-PPS alone, respectively, and a mean of 1.2 × 102, 4.3 × 103, and 5.9 × 104 CFUs, respectively, on culture of the surrounding tissue (p < 0.05). Conclusions: The PEG-PPS coating provides a promising approach to preventing periprosthetic infection. This polymer is novel in that it combines both passive and active antibiotic-release mechanisms. The tigecycline-based coating outperformed the vancomycin-based coating in this study. Clinical Relevance: PEG-PPS polymer provides a controlled, “smart” local delivery of antibiotics that could be used to prevent postoperative implant-related infections.

Long-term bisphosphonate use has often been associated with atypical femoral fractures. These fractures evolve from incomplete femoral fractures. A previous study demonstrated that the presence of a radiolucent line in an incomplete fracture can indicate a high risk of progression to complete fracture.The aim of this study is to present a management strategy for symptomatic bisphosphonate-associated incomplete atypical femoral fractures. Specific study questions include the following: (1) Is there a difference in the prognosis of these fractures based on the presence or absence of a radiolucent fracture line? (2) Can treatment with teriparatide assist in clinical/radiographic healing of these incomplete fractures? (3) Is there a characteristic biochemical profile in these patients?We retrospectively examined all femur radiographs ordered by the metabolic bone disease service at our hospital between July 1, 2006 and July 1, 2011 and identified 10 patients with a total of 14 incomplete fractures. Nine patients received bisphosphonates for a mean duration of 10 ± 5 years (range, 4-17). The mean follow-up since the time of diagnosis was 20 ± 11 months (range, 6-36 months).Five fractures did not have a radiolucent fracture line and were treated conservatively with partial weight-bearing restrictions and pharmacologic therapy. All five of these fractures healed with conservative management. Nine fractures had a radiolucent fracture line, and only two of these were treated successfully with conservative management including teriparatide. Six of the eight patients with a radiolucent line elected for surgical prophylaxis after 3 months of conservative management, whereas one patient underwent surgical prophylaxis without a trial of conservative management. Regarding the biochemical profiles, bone turnover markers for our patient cohort were in the lower quartile.Fractures without a radiolucent line appear to respond to conservative management and not require surgical prophylaxis. Teriparatide treatment may hold promise in promoting healing of these fractures.

BACKGROUND CONTEXT Surgical debridement of spine infections consists of excising tissue at the surgeon's discretion. Surgeon's rely on visual cues such as abnormal tissue coloration and consistency to determine the extent of debridement. However, complete and accurate debridement is difficult to assess given the lack of objective data with regard to location and extent of residual infection. PURPOSE The purpose of this study is to apply two emerging technologies: (1) novelStaphylococcus aureustargeting fluorescently labeled probes and (2) “OR ready” real-time fluorescent imaging system, in a proof of principle study evaluating the feasibility of image-guided debridement surgery. STUDY DESIGN/SETTING This is a basic science investigation utilizing a mouse model of spinal implant infection. BioluminescentStaphylococcus aureusis used for longitudinal quantification of bacterial burden. Once infections were established, an open-air, “OR ready” fluorescent imaging system was utilized for image guided surgery. PATIENT SAMPLE Thirty-six 12-week-oldC57BL/6 wild type mice were utilized, 10 for each experimental group. OUTCOME MEASURES Utilizing an established mouse model of spinal implant infection,in vivobioluminescence and fluorescence imaging was performed to quantify emitted signals. A recently developed open-air, fluorescence input image-guided surgery system was utilized to for debridement surgery and to evaluate residual bacterial burden on debrided tissue. METHODS Three groups of mice were subjected to a previously established spine implant infection model: (1) five mice with implants inoculated withS. aureusand one sterile control mouse 60 days prior to image-guided debridement, (2) 10 inoculated and five sterile mice 30 days prior, (3) 10 inoculated and five sterile control mice 7 days prior. A total of 24 hours prior to debridement surgery, aS. aureusImmunodominant Staphylococcal Antigen A (IsaA) antibody fluorescent probe was administered via tail vein injection. Fluorescent imaging was completed to confirm co-localization of the probe to bioluminescent bacteria. Mice were then subjected to a fluorescence image-guided surgery system for debridement. RESULTS Two of five mice from the 60-day group, 8/10 of the 30-day group, and 10/10 of the 7-day group established an infection confirmed by bioluminescence imaging. Subsequent fluorescence imaging following IsaA-antibody probe injection revealed co-localization of fluorescent probe to bioluminescent bacteria with high fidelity. Radical debridement of fluorescent material under the image-guided surgery system was completed which revealed fluorescently labeled tissue with continued light emissionex-vivo.No fluorescence remained in mice status post debridement, indicating successful infection excision. CONCLUSIONS The novel,S. aureusspecific fluorescent probe successfully labelled bacteria in chronic and acute spine implant infections.Furthermore, this probe was successfully applied to the image-guided surgery system.This technology has the potential to shift the paradigm in excision surgery with applications in infection and negative margin tumor surgery.

Metastatic disease to the pelvis can lead to structural instability and debilitating pain. Lesions are often quite large at the time of diagnosis, as the size of the pelvis and elastic nature of the peri-pelvic organs often result in few symptoms of mass effect for smaller lesions. Lesions are classified by biologic subtype and location based on the system of Enneking—iliac (Type I), periacetabular (Type II), rami (Type III), and sacrum (Type IV) [1]. Advanced 3-dimensional imaging of the lesion is essential to adequately assess the anatomy and structural stability of the pelvis. Only posterior column Type I and Type II lesions typically lead to issues with structural stability. The majority of cases of pelvic metastatic disease can be managed nonoperatively with pain management and radiation therapy, as most are at least moderately sensitive to radiation. Occasionally, however, due to intractable pain, compromised pelvic stability, or (rarely) for the reduction of oncologic disease burden, surgical intervention is indicated. These interventions are divided into intralesional procedures such as curettage with or without adjuvant therapies and possible cemented reconstruction; and wide, extralesional procedures including internal and external hemipelvectomies. The extended ilioinguinal approach can be used for most lesions, in addition to the anterolateral or posterior approaches to the hip for periacetabular lesions. As most Type I, III, and IV lesions do not compromise the structural integrity or weight-bearing capacity of the patient, intralesional and extralesional resections are typically followed with no attempt at reconstruction. Conversely, there has been much debate over reconstruction methods after resection of Type II lesions and many options exist, ranging from custom arthroplasty implants to allograft reconstructions to cement-rebar constructs to simply leaving a flail hip. Type IV lesions that require resection of greater than 50 % of the sacroiliac joint compromise pelvic stability and therefore often require hardware to prevent dissociation and limb length discrepancy. In all cases, wound closure with adequate soft tissue coverage is critical, as complications such as dehiscence, infection and herniation can be devastating. If the wound cannot be closed without significant tension, a flap should be used. While morbidity for these surgeries is significant, treatment of these lesions has been shown to improve patient quality of life. The benefits of surgery should always be weighed against the risks and life expectancy of the patient prior to proceeding with surgery. As medical advances have increased patient survival for many types of metastatic cancer, orthopedic oncologists must now evaluate and hone our resection and reconstruction techniques to achieve longer lasting, commensurate results.

While the gold standard of treatment of nonunion is open autologous bone grafting, studies have shown that injecting bone marrow aspirate concentrates (BMAC) is effective in treating tibial nonunions with fracture gaps less than 5 mm.We aim to demonstrate that combining BMAC with osteoinductive agents can effectively treat delayed or nonunion regardless of fracture gap size, nonunion site, or osteoinductive agent used.In this non-randomized retrospective-prospective cohort study, 49 patients with tibial nonunion met the inclusion criteria and underwent BMAC injection with demineralized bone matrix (DBM) and/or recombinant human bone morphogenic protein-2 (rhBMP-2). Radiologic healing of the fracture was the primary outcome. Patients were followed until radiographic union was achieved or another procedure was performed. Radiographic healing was defined as bridging of three out of four cortices on anteroposterior and lateral films.There was no difference in the healing rate (p = 0.81) between patients with fracture gaps less than and greater than 5 mm. On multivariate analysis, the use of rhBMP-2 was associated with a lower healing rate compared to DBM (p = 0.036). Patients who underwent early intervention (within 6 months of fixation) had higher union rates (p = 0.04).This study shows that percutaneous BMAC injection combined with either DBM and/or rhBMP-2 is a safe and effective treatment for delayed or nonunion regardless of the fracture gap size or fracture site. DBM may be superior to rhBMP-2 in this procedure.

Postoperative surgical site infection (SSI) is a common complication after posterior lumbar spine surgery. This review details an approach to the prevention, diagnosis and treatment of SSIs. Factors contributing to the development of a SSI can be split into three categories: (1) microbiological factors; (2) factors related to the patient and their spinal pathology; and (3) factors relating to the surgical procedure. SSI is most commonly caused by Staphylococcus aureus. The virulence of the organism causing the SSI can affect its presentation. SSI can be prevented by careful adherence to aseptic technique, prophylactic antibiotics, avoiding myonecrosis by frequently releasing retractors and preoperatively optimizing modifiable patient factors. Increasing pain is commonly the only symptom of a SSI and can lead to a delay in diagnosis. C-reactive protein and magnetic resonance imaging can help establish the diagnosis. Treatment requires acquiring intra-operative cultures to guide future antibiotic therapy and surgical debridement of all necrotic tissue. A SSI can usually be adequately treated without removing spinal instrumentation. A multidisciplinary approach to SSIs is important. It is useful to involve an infectious disease specialist and use minimum serial bactericidal titers to enhance the effectiveness of antibiotic therapy. A plastic surgeon should also be involved in those cases of severe infection that require repeat debridement and delayed closure.

Previous studies have demonstrated the distinct advantages of thoracoscopically assisted spinal fusion compared to traditional open thoracotomy. However, these techniques are limited by a steep learning curve, prolonged operative time, and lack of three-dimensional visualization of the surgical field.The objective of this study was to describe our initial experience with an adaptation of the extreme lateral interbody fusion (XLIF) technique allowing access to the anterior aspect of the thoracic and thoracolumbar spine with specific reference to (1) early pulmonary complications, (2) non-pulmonary complications, and (3) ability of this technique to successfully achieve spinal decompression and fusion at the operative level.Clinical and radiographic data were reviewed for the entire perioperative period. A total of 18 patients (72% females; mean age, 56.8 years) underwent a thoracic XLIF procedure for spinal pathologies including disc herniation, fracture, tumor, pseudoarthrosis, and proximal junctional kyphosis. A total of 32 levels were treated, with the majority located at the thoracolumbar junction. Twelve of the procedures were done as part of a combined anterior/posterior surgery.The mean estimated blood loss was 577 ml and the mean length of stay was 12 days. At a mean follow-up of 14 months, all patients except for one (who died of widely metastatic disease) had achieved radiographic evidence of fusion. Two patients developed pulmonary effusions requiring medical intervention. Six patients had seven non-pulmonary complications: incidental durotomy (two), infection (one), instrumentation pullout (one), cardiac arrhythmia (two), and death from metastatic disease (one).The XLIF technique can be utilized for access to the anterior column of the thoracic and thoracolumbar spine. The advantages of this minimally invasive technique include avoidance of the need for an access surgeon and for lung deflation during surgery as well as excellent visualization of the spinal pathology.