Joshua C. Patt

Adipose-Derived Stem Cells: Characterization and Current Application in Orthopaedic Tissue Repair

Orthopaedic tissues, such as bone, cartilage, intervertebral disc and tendon, contain cells that are difficult to culture and stimulate in vitro for repair of damaged tissue. Stem cells have the ability to self-renew and differentiate into many tissue types. Recent progress in stem cell research has led to an enthusiastic effort to utilize stem cells for orthopaedic tissue regeneration. Due to ease of harvest and abundance, adipose-derived mesenchymal cells (ASC) are an attractive, readily available adult stem cell that has become increasingly popular for use in many stem cell applications. Recent progress has been made in characterizing ASC and looking mechanistically at gene expression and cellular pathways involved in differentiation. This review focuses on (i) the characterization of ASC through expression of appropriate surface markers; (ii) modulation of in vitro differentiation of ASC through different scaffolds, growth factors, and media; and (iii) the use of ASC in orthopaedic tissue repair. Strategies for repair involve the use of differentiated or undifferentiated, fresh or passaged ASC, in conjunction with appropriate choice of media, growth factors and scaffolds. Recent in vivo studies utilizing ASC are discussed giving results on defect repair and potential for clinical orthopaedic tissue regeneration.

Is PET useful in detecting occult nonpulmonary metastases in pediatric bone sarcomas

Orthopaedic oncologists are increasingly utilizing positron emission tomography (PET) technology in the initial workup and staging of sarcomas and for monitoring treatment response. We evaluated the use of PET with fluorine-18-fluoro- 2-deoxy D-glucose (FDG) to detect occult nonpulmonary metastases in patients < age 30 newly diagnosed with either Ewings or osteosarcoma, and the impact of this information upon therapeutic decision making. We retrospectively reviewed prospectively collected data (1994-2004) on 55 patients age < 30 years old over a 10 year span. PET detected metastases in 12/55 (22%) of these patients, eight of whom (67%) harbored disease outside the lung; however, only 4/55 (7%) were upstaged to Stage IV specifically due to findings determined by PET alone. Three of 17 (18%) Ewings sarcoma patients, but only one of 38 (3%) osteosarcoma patients, were upstaged by PET alone. The most important alteration in treatment decisions was the substitution of irradiation in lieu of surgery for local control in Ewings sarcoma patients.Level of Evidence: Diagnostic study, level II. See Guidelines for Authors for a complete description of levels of evidence.

What factors influence applicants' rankings of orthopaedic surgery residency programs in the National Resident Matching Program?

BackgroundIn accordance with the American Academy of Orthopaedic Surgeons’ strategic goal of enriching our field by building a more diverse orthopaedic workforce, the specialty needs further information delineating the factors important to the applicant pool as a whole and more specifically to women and other underrepresented minority groups.Questions/purposesThis study aims to identify (1) factors important to residency applicants selecting an orthopaedic residency program; (2) differences in factor importance for men, women, and minorities, and (3) the importance of different information sources used when making his or her rank list.MethodsAll 742 applicants who applied to the authors’ orthopaedic surgery residency program in the 2013 National Resident Matching Program were queried. The response rate was 28% (207 of 742). Respondents were asked to rank, on a 5-point Likert scale, 37 factors that may have affected their rank lists to differing degrees. Respondents also identified the importance of sources of information used to make their rank lists, factors that residency programs considered important when ranking applicants, and their level of agreement with various sex- and racial-specific statements regarding orthopaedic training.ResultsThe most important factors affecting rank lists were perceived happiness/quality of life of current residents, resident camaraderie, and impression after an away rotation. Women weighed their personal interactions and a program’s proximity to family and friends more heavily when determining a rank list. Sixty-eight percent of women eliminated residency programs from their options based on perceived sex biases versus less than 1% of men. Applicants valued information obtained from away rotations at an institution and in talking with current residents most when determining his or her rank list.ConclusionsPrograms should consider interpersonal factors, like quality of life and resident camaraderie as factors in attracting applicants. They also should minimize perceived biases and emphasize interactions with current residents during the application process to meet their goals of attracting an exceptional and more diverse orthopaedic workforce.

Does Intrawound Vancomycin Application During Spine Surgery Create Vancomycin-Resistant Organism?

BACKGROUND: Surgical site infection (SSI) following spine surgery is a morbid and expensive complication. The use of intrawound vancomycin is emerging as a solution to reduce SSI. The development of vancomycin‐resistant pathogens is an understandable concern. OBJECTIVE: To determine the occurrence of vancomycin‐resistant SSI in patients with and without use of intrawound vancomycin. METHODS: Patients undergoing elective spine surgery were dichotomized based on whether intrawound vancomycin was applied. Outcome was occurrence of SSI requiring return to the operating room within postoperative 90 days. The intrawound culture and vancomycin minimal inhibitory concentrations (MIC) were reviewed. Analyses were conducted to compare the pathogen profile and MIC for vancomycin in patients who received vancomycin and those who did not. RESULTS: Of the total 2802 patients, 43% (n = 1215) had intrawound vancomycin application during the index surgery. The use of vancomycin was associated with significantly lower deep SSI rates (1.6% [n = 20] vs 2.5% [n = 40], P = .02). The occurrence of Staphylococcus aureus SSI was significantly lower in the patients who had application of intrawound vancomycin (32% vs 65%, P = .003). None of the patients who had application of intrawound vancomycin powder, and subsequently developed an S aureus SSI, demonstrated pathogens with resistance to vancomycin. All patients had MIC < 2 &mgr;g/mL, the vancomycin susceptibility threshold. The occurrence of gram‐negative SSI (28% vs 7%) and culture negative fluid collection (16% vs 5%) was higher in the vancomycin cohort. CONCLUSIONS: The use of intrawound vancomycin during the index spine surgery was protective against SSI following spine surgery. The application of intrawound vancomycin during index surgery does not appear to create vancomycin‐resistant organisms in the event of an SSI.

Intrawound Vancomycin Decreases the Risk of Surgical Site Infection After Posterior Spine Surgery: A Multicenter Analysis

Study Design. Secondary analysis of data from a prospective multicenter observational study. Objective. The aim of this study was to evaluate the occurrence of surgical site infection (SSI) in patients with and without intrawound vancomycin application controlling for confounding factors associated with higher SSI after elective spine surgery. Summary of Background Data. SSI is a morbid and expensive complication associated with spine surgery. The application of intrawound vancomycin is rapidly emerging as a solution to reduce SSI following spine surgery. The impact of intrawound vancomycin has not been systematically studied in a well-designed multicenter study. Methods. Patients undergoing elective spine surgery over a period of 4 years at seven spine surgery centers across the United States were included in the study. Patients were dichotomized on the basis of whether intrawound vancomycin was applied. Outcomes were occurrence of SSI within postoperative 30 days and SSI that required return to the operating room (OR). Multivariable random-effect log-binomial regression analyses were conducted to determine the relative risk of having an SSI and an SSI with return to OR. Results. . A total of 2056 patients were included in the analysis. Intrawound vancomycin was utilized in 47% (n = 966) of patients. The prevalence of SSI was higher in patients with no vancomycin use (5.1%) than those with use of intrawound vancomycin (2.2%). The risk of SSI was higher in patients in whom intrawound vancomycin was not used (relative risk (RR) -2.5, P < 0.001), increased number of levels exposed (RR -1.1, P = 0.01), and those admitted postoperatively to intensive care unit (ICU) (RR -2.1, P = 0.005). Patients in whom intrawound vancomycin was not used (RR -5.9, P < 0.001), increased number of levels were exposed (RR-1.1, P = 0.001), and postoperative ICU admission (RR -3.3, P < 0.001) were significant risk factors for SSI requiring a return to the OR. Conclusion. The intrawound application of vancomycin after posterior approach spine surgery was associated with a reduced risk of SSI and return to OR associated with SSI. Level of Evidence: 2

Open Reduction vs Distal Femoral Replacement Arthroplasty for Comminuted Distal Femur Fractures in the Patients 70 Years and Older

BACKGROUND The ideal management of distal femur fractures in the elderly is unclear. Acute arthroplasty has the theoretical advantage of earlier mobilization. We examined the outcomes of patients 70 years and older who underwent open reduction internal fixation (ORIF) vs distal femoral replacement (DFR) for comminuted, intra-articular distal femur fractures. METHODS A retrospective review of patients with AO/OTA classification 33C distal femur fractures treated with either ORIF or DFR was performed. Outcomes including all-cause reoperation, length of stay, fracture union, postoperative complications, use of ambulatory device and living situation at 1 year, and mortality were evaluated. RESULTS The study cohort included 38 patients: 10 underwent DFR and 28 ORIF. Mean patient age for both cohorts was 82 years. No difference in comorbidities or mechanism of injury was found between groups. The incidence of reoperation was 11% in the ORIF group and 10% in the DFR group. In the ORIF group, the average time to fracture union was 24 weeks, with a nonunion incidence of 18%. Twenty-three percent of ORIF group were wheelchair dependent vs none in the DFR cohort, although not statistically significant. Differences between the groups with respect to all-cause reoperation, living situation or need for ambulatory device at 1 year, and 1-year mortality did not reach statistical significance. CONCLUSION Nearly 1 in 5 patients older than 70 years developed a nonunion after ORIF of an intra-articular distal femur fracture. At 1-year follow-up, all patients in DFR group were ambulatory while 1 in 4 in the ORIF group were wheelchair bound.

Soft tissue sarcomas in skin: presentations and management

Soft tissue sarcomas are a rare but heterogeneous family of malignant tumors that are predominantly found deep to the integumentary layer. Only a small number of these primary mesenchymal tumors actually originate from the dermal layers. A systematic approach to the evaluation and workup of these neoplasms can prevent inappropriate management. After staging evaluation, most of these tumors are primarily managed with en-bloc surgical resection. Other adjuvant therapies routinely employed include chemotherapy and radiation therapy. Proper treatment typically involves participation of a multidisciplinary care team for optimal outcome. General principles and treatment strategies will be discussed along with a review of the more common cutaneous manifestations of sarcoma.

Effect of Polyether Ether Ketone on Therapeutic Radiation to the Spine: A Pilot Study.

Study Design. Cadaveric model. Objectives. To compare the effect of PEEK versus conventional implants on scatter radiation to a simulated tumor bed in the spine Summary of Background Data. Given the highly vasculature nature of the spine, it is the most common place for bony metastases. After surgical treatment of a spinal metastasis, adjuvant radiation therapy is typically administered. Radiation dosing is primarily limited by toxicity to the spinal cord. The scatter effect caused by metallic implants decreases the accuracy of dosing and can unintentionally increase the effective dose seen by the spinal cord. This represents a dose-limiting factor for therapeutic radiation postoperatively. Methods. A cadaveric thorax specimen was utilized as a metastatic tumor model with two separate three-level spine constructs (one upper thoracic and one lower thoracic). Each construct was examined independently. All four groups compared included identical posterior instrumentation. The anterior constructs consisted of either: an anterior polyether ether ketone (PEEK) cage, an anterior titanium cage, an anterior bone cement cage (polymethyl methacrylate), or a control group with posterior instrumentation alone. Each construct had six thermoluminescent detectors to measure the radiation dose. Results. The mean dose was similar across all constructs and locations. There was more variability in the upper thoracic spine irrespective of the construct type. The PEEK construct had a more uniform dose distribution with a standard deviation of 9.76. The standard deviation of the others constructs was 14.26 for the control group, 19.31 for the titanium cage, and 21.57 for the cement (polymethyl methacrylate) construct. Conclusion. The PEEK inter-body cage resulted in a significantly more uniform distribution of therapeutic radiation in the spine when compared with the other constructs. This may allow for the application of higher effective dosing to the tumor bed for spinal metastases without increasing spinal cord toxicity with either fractionated or hypofractionated radiotherapy. Level of Evidence: N/A

The use of an interference fit retrograde nail as an adjunct to plate fixation of a complex Vancouver B1 periprosthetic femoral fracture

As the number of hip arthroplasties performed continues to grow, increasingly complex periprosthetic fractures are encountered. In particular, fractures occurring near the tip of a well-fixed stem, classified as Vancouver B1, have been associated with high rates of failure. Numerous treatment strategies have been recommended including traditional plating, locked plating, cortical allografts as well as retrograde nails overlapping the femoral stem tip. The latter technique has been advocated as a less invasive method to stabilise periprosthetic fractures in elderly, lowdemand patients unfit for extensive surgical procedures. Here, we present the use of a retrograde nail overlapping a femoral stem in a young, active patient as supplemental fixation to a lateral plate for the difficult situation of a Vancouver B1 periprosthetic fracture proximal to an femoral shaft hypertrophic nonunion.

CORR Insights(®): Sacral Insufficiency Fractures are Common after High-dose Radiation for Sacral Chordomas Treated With or Without Surgery.

C hordoma is a rare malignant tumor of the vertebral column that is thought to arise from notocordal rest cells. The tumors characteristically occur in the midline of the neuro-central axis, from the skull base to the sacrum. The highest percentage of these are seen distally, frequently arising from the sacrococcygeal junction, and surgical resection is the treatment of choice for these tumors. However, the complex anatomy of the neural axis can make obtaining acceptable margins challenging. The ideal surgical treatment consists of resection with wide margins, but it remains challenging to preserve essential neural function and avoid injury to visceral and vascular structures during resection. Frequently, margins are positive, marginal, or contaminated [7–9] and adjuvant treatment strategies must be considered. The most common adjuvant treatment employed is radiation therapy, but because chordomas often are radioresistant, high dose radiotherapy (> 60 Gy) generally is used [1]. Highly conformal strategies such as proton beam or stereotactic radiosurgery techniques are commonly employed to maximize dose to the operative bed. Some institutions have employed neoadjuvant radiation as a strategy to try and improve local control—as is the protocol at the authors’ institution [1]. One of the critiques of radiation therapy is that it can cause pathological fractures of bones that lie in the radiation field [4]. While prior studies of chordoma have appropriately pointed out the major morbidity and mortality associated with sacral resections [5, 7, 10], the authors recognized a disparity between prior studies and their own cohort with respect to this functionally relevant complication of sacral insufficiency fractures. The current paper takes a focused look at this common complication of This CORR Insights is a commentary on the article ‘‘Sacral Insufficiency Fractures are Common after High-dose Radiation for Sacral Chordomas Treated With or Without Surgery’’ by Osler and colleagues available at: DOI: 10.1007/s11999-015-4566-5. The author certifies that he, or any member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at DOI: 10.1007/s11999-0154566-5. J. C. Patt MD, MPH (&) Department of Orthopaedic Surgery, Carolinas Medical Center, Levine Cancer Institute, 1025 Morehead Medical Dr. Suite 300, Charlotte, NC 28204, USA e-mail: joshua.patt@carolinashealthcare.org; joshuapatt@hotmail.com CORR Insights Published online: 30 October 2015 The Association of Bone and Joint Surgeons1 2015