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Few regenerative approaches exist for the treatment of injuries to adult dense connective tissues. Compared to fetal tissues, adult connective tissues are hypocellular and show limited healing after injury. We hypothesized that robust repair can occur in fetal tissues with an immature extracellular matrix (ECM) that is conducive to cell migration, and that this process fails in adults due to the biophysical barriers imposed by the mature ECM. Using the knee meniscus as a platform, we evaluated the evolving micromechanics and microstructure of fetal and adult tissues, and interrogated the interstitial migratory capacity of adult meniscal cells through fetal and adult tissue microenvironments with or without partial enzymatic digestion. To integrate our findings, a computational model was implemented to determine how changing biophysical parameters impact cell migration through these dense networks. Our results show that the micromechanics and microstructure of the adult meniscus ECM sterically hinder cell mobility, and that modulation of these ECM attributes via an exogenous matrix-degrading enzyme permits migration through this otherwise impenetrable network. By addressing the inherent limitations to repair imposed by the mature ECM, these studies may define new clinical strategies to promote repair of damaged dense connective tissues in adults.

Dense connective tissue injuries have limited repair, due to the paucity of cells at the wound site. We hypothesize that decreasing the density of the local extracellular matrix (ECM) in conjunction with releasing chemoattractive signals increases cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue., Dense connective tissues do not easily heal, in part due to a low supply of reparative cells. Here, the authors develop a fibrous scaffold for meniscal repair that sequentially releases collagenase and a growth factor at the injury site, breaking down the extracellular matrix and recruiting endogenous cells.

Venous thromboembolism (VTE) is an important problem in orthopedic trauma patients. An association between VTE and upper extremity injury has not been reported. The purpose of this investigation was to determine whether upper extremity trauma is an independent risk factor for lower extremity VTE. This study also attempted to identify associations between VTEs and demographic and injury variables in patients that sustained upper extremity trauma. Eleven years of data from the trauma registry at our Level I trauma center was retrospectively reviewed in an injury-matched cohort study. From an initial pool of 646 patients who sustained upper extremity trauma, 32 subjects (4.95%) were identified as having major upper extremity injuries as well as thromboembolic complications. Thirty-two injury-matched controls were randomly selected from the 646 patients with major upper extremity injuries. Regression analysis was performed to determine variables that were significantly associated with lower extremity thromboembolic complications. Overall incidence of VTE in patients sustaining upper extremity injury was 4.95% (deep vein thrombus 4.64%, pulmonary embolism 0.31%) and was similar to the 4.95% VTE rate in patients without upper extremity injury. Major head injury (p = 0.022) occurred at increased frequency in the VTE group. Patients with increased length of hospital stay (p

Abstract Lower extremity peripheral arterial disease (PAD) and musculoskeletal conditions both produce symptoms of leg pain, and may coexist. This study assesses the prevalence of PAD among patients referred to orthopedic surgery for evaluation of lower extremity pain. Fifty consecutive patients aged 50 years or more who had a chief complaint of leg pain, no history of trauma, and no previous history of PAD were studied prospectively. The presence of known risk factors for PAD and classic claudication symptoms was assessed by telephone interview and medical record review. Individuals were then evaluated by measurement of the ankle–brachial index (ABI) using Doppler and pulse volume recordings (PVR). A patient was deemed to have PAD if the ABI was below 0.9 or if the PVR demonstrated significant abnormalities. Occult PAD was detected in 10 of the 50 patients (20%) on the basis of the non-invasive vascular studies. There were no differences between patients with PAD and those without PAD regarding the presence of risk factors for PAD. None of the patients without PAD had claudication, while only one of the 10 patients with PAD had symptoms of classic claudication. In conclusion, 20% of patients referred by primary care providers to the orthopedic surgery clinic for lower extremity pain were discovered to have occult PAD. The majority of these patients did not have claudication. Orthopedic surgeons and primary care providers must maintain an appropriately high index of suspicion for PAD when evaluating patients with non-traumatic lower extremity pain.

Item does not contain fulltext BACKGROUND: The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively evaluated in groups of patients with osteoarthritis, yet not in patients with a femoral neck fracture. This study aimed to determine the reliability, construct validity, and responsiveness of the WOMAC compared with the Short Form-12 (SF-12) and the EuroQol 5D (EQ-5D) questionnaires for the assessment of elderly patients with a femoral neck fracture. METHODS: Reliability was tested by assessing the Cronbach alpha. Construct validity was determined with the Pearson correlation coefficient. Change scores were calculated from ten weeks to twelve months of follow-up. Standardized response means and floor and ceiling effects were determined. Analyses were performed to compare the results for patients less than eighty years old with those for patients eighty years of age or older. RESULTS: The mean WOMAC total score was 89 points before the fracture in the younger patients and increased from 70 points at ten weeks to 81 points at two years postoperatively. In the older age group, these scores were 86, 75, and 78 points. The mean WOMAC pain scores before the fracture and at ten weeks and two years postoperatively were 92, 76, and 87 points, respectively, in the younger age group and 92, 84, and 93 points in the older age group. Function scores were 89, 68, and 79 points for the younger age group and 84, 71, and 73 points for the older age group. The Cronbach alpha for pain, stiffness, function, and the total scale ranged from 0.83 to 0.98 for the younger age group and from 0.79 to 0.97 for the older age group. Construct validity was good, with 82% and 79% of predefined hypotheses confirmed in the younger and older age groups, respectively. Responsiveness was moderate. No floor effects were found. Moderate to large ceiling effects were found for pain and stiffness scales at ten weeks and twelve months in younger patients (18% to 36%) and in the older age group (38% to 53%). CONCLUSIONS: The WOMAC showed good reliability, construct validity, and responsiveness in both age groups of elderly patients with a femoral neck fracture who had been physically and mentally fit before the fracture. The instrument is suitable for use in future clinical studies in these populations. CLINICAL RELEVANCE: The results are based on two clinical trials. The questionnaires used concern pure, clinically relevant issues (ability to walk, climb stairs, etc.). Moreover, the results can be used for future research comparing clinical outcomes (or treatments) for populations with a femoral neck fracture.

Despite advances in tissue engineering for the knee meniscus, it remains a challenge to match the complex macroscopic and microscopic structural features of native tissue, including the circumferentially and radially aligned collagen bundles essential for mechanical function. To mimic this structural hierarchy, this study developed multi-lamellar mesenchymal stem cell (MSC)-seeded nanofibrous constructs. Bovine MSCs were seeded onto nanofibrous scaffolds comprised of poly(ε-caprolactone) with fibers aligned in a single direction (0° or 90° to the scaffold long axis) or circumferentially aligned (C). Multi-layer groups (0°/0°/0°, 90°/90°/90°, 0°/90°/0°, 90°/0°/90°, and C/C/C) were created and cultured for a total of 6 weeks under conditions favoring fibrocartilaginous tissue formation. Tensile testing showed that 0° and C single layer constructs had stiffness values several fold higher than 90° constructs. For multi-layer groups, the stiffness of 0°/0°/0° constructs was higher than all other groups, while 90°/90°/90° constructs had the lowest values. Data for collagen content showed a general positive interactive effect for multi-layers relative to single layer constructs, while a positive interaction for stiffness was found only for the C/C/C group. Collagen content and cell infiltration occurred independent of scaffold alignment, and newly formed collagenous matrix followed the scaffold fiber direction. Structural hierarchies within multi-lamellar constructs dictated biomechanical properties, and only the C/C/C constructs with non-orthogonal alignment within layers featured positive mechanical reinforcement as a consequence of the layered construction. These multi-layer constructs may serve as functional substitutes for the meniscus as well as test beds to understand the complex mechanical principles that enable meniscus function.

During surgical training, medical students and residents constantly are reminded to culture every suspected tumor and send tissue for pathologic evaluation for every suspected abscess. A diagnosis of cancer can be missed easily if this procedure is not followed, delaying the diagnosis and possibly adversely affecting the patient's prognosis. The confusion also may be compounded by a sterile abscess, positive culture results or a negative biopsy specimen. Therefore it is imperative to do a biopsy and a culture on any suspect lesion. An additional workup and possible biopsy may be warranted for a nonhealing wound that has been treated appropriately. The cases of three patients with lymphoma that were treated as infectious processes are presented. In all three instances, the appropriate treatment was delayed because of a delay in diagnosis.

INTRODUCTION/ PURPOSE: The widespread occurrence of muscular atrophy during immobilization and its reversal presents an important challenge to rehabilitation medicine. We used 3D-magnetic resonance imaging (MRI) in patients with surgically-stabilized ankle mortise fractures to quantify changes in plantarflexor and dorsiflexor muscle size during immobilization and rehabilitation, as well as to evaluate changes in force generating capacity (specific torque).Twenty-individuals participated in a 10 wk rehabilitation program after 7 wk of immobilization. MRIs were acquired at baseline, 2, and 7 wk of immobilization, and at 5 and 10 wk of rehabilitation. Isometric plantarflexor muscle strength testing was performed at 0, 5, and 10 wk of rehabilitation.Dorsiflexors and plantarflexors atrophied 18.9% and 24.4% respectively, the majority of which occurred during the first 2 wk of immobilization (dorsiflexors: 9.6%; plantarflexors: 14.1%). Likewise, more than 50% of hypertrophy during rehabilitation occurred within the first 5 wk of rehabilitation for both the dorsiflexors (12.9%) and plantarflexors (13.2%), when compared to the total amount of hypertrophy over 10 wk of rehabilitation (dorsiflexors: 17.6%, plantarflexors: 22.5%). There were no significant differences in hypertrophy or atrophy of the dorsiflexor or plantarflexor muscles, despite a rehabilitation emphasis on the plantarflexors. Patients had significantly lower plantarflexor specific torque (torque/CSA) than healthy, control subjects immediately after cast immobilization, which did not return to normal after 10 wk of rehabilitation (P0.05).Our investigation of the consequences of limb immobilization on rehabilitation outcomes in patients can be applied directly to optimizing rehabilitation programs. Although muscle hypertrophy occurred early during rehabilitation, plantarflexor muscle function (specific torque) should remain the focus of rehabilitation programs because although CSA recovered quickly, specific torque still lagged behind that of control subjects.

The documented history of the management of infections of the musculoskeletal system date back to ancient Egypt, and great strides have been made since, especially in the last two centuries. This chapter presents an overview of the important achievements in treating these conditions, as well as some of the challenges faced by the various physicians—from Hippocrates to Lister—who sought to cure them. Because of the constraints of chapter length and the excellent current literature available, no attempt will be made to deal with the past fifty years.

OBJECTIVES We hypothesized that the method of stress external rotation more accurately reproduces the mechanism of injury, and therefore this diagnostic method more likely detects ankle instability than the fibular stress examination. DESIGN Prospective cohort comparison study. SETTING Level 1 trauma center. PATIENTS Twenty-eight consecutive patients with unstable ankle fractures presenting within 7 days from the time of injury. Previous ankle surgical history or age younger than 18 years was excluded. INTERVENTION Stress external rotation and lateral fibular stress examination was performed intraoperatively. MAIN OUTCOME MEASURE Radiographic measurement of the tibiofibular clear space, tibiofibular overlap, and medial clear space were recorded. RESULTS After normalization of the fluoroscopic measurements, there was no difference in detecting changes in tibiofibular clear space or tibiofibular overlap. However, there was a significant difference in detecting medial clear space widening with stress external rotation. Compared with lateral fibular stress, stress external rotation demonstrated a 35% increase (P < 0.05) in medial clear space widening. This difference correlates with the 1-2-mm difference of additional widening with stress external rotation. CONCLUSIONS Untreated instability impacts patient outcomes. The difference in widening with stress external rotation was significantly greater than lateral fibular stress and appreciable on standard fluoroscopic views. Stress external rotation radiographs are a more reliable indicator of mortise instability than traditional lateral fibular stress. LEVEL OF EVIDENCE Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Repair of dense connective tissues in adults is limited by their intrinsic hypocellularity and is exacerbated by a dense extracellular matrix (ECM) that impedes cellular migration to and local proliferation at the wound site. Conversely, healing in fetal tissues occurs due in part to an environment conducive to cell mobility and division. Here, we investigated whether the application of a degradative enzyme, collagenase, could reprogram the adult wound margin to a more fetal-like state, and thus abrogate the biophysical impediments that hinder migration and proliferation. We tested this concept using the knee meniscus, a commonly injured structure for which few regenerative approaches exist. To focus delivery and degradation to the wound interface, we developed a system in which collagenase was stored inside poly(ethylene oxide) (PEO) electrospun nanofibers and released upon hydration. Through a series of in vitro and in vivo studies, our findings show that partial digestion of the wound interface improves repair by creating a more compliant and porous microenvironment that expedites cell migration to and/or proliferation at the wound margin. This innovative approach of targeted manipulation of the wound interface, focused on removing the naturally occurring barriers to adult tissue repair, may find widespread application in the treatment of injuries to a variety of dense connective tissues.

Osteomyelitis and septic arthritis can result in considerable morbidity in adults, especially when the diagnosis is delayed. The physiologic status of the host is an important variable, and surgical care is frequently required in addition to antibiotics to eradicate infection and treat complications.

Background and Purpose. The goal of this investigation was to study the recovery of ankle plantar-flexor peak torque, fatigue resistance, and functional ability (stair climbing, walking) following cast immobilization in patients with ankle fractures. Subjects. The participants were 10 patients who underwent open reduction-internal fixation and 8 weeks of cast immobilization following a fracture of the ankle mortise and 10 age- and sex-matched, noninjured comparison subjects. Methods. Plantar-flexor torque and fatigue resistance were measured at 1, 5, and 10 weeks of rehabilitation using an isokinetic dynamometer. Ankle plantar-flexor peak torque and fatigue resistance were correlated to timed ambulation, timed stair climbing, and unilateral heel-rises. Results. Following immobilization, plantar-flexor peak torque was decreased at all angular speeds and positions. The decrease in peak torque was associated with an increase in fatigue resistance. With rehabilitation, ankle plantar-flexor torque and fatigue resistance normalized. Regression analysis revealed a strong relationship between plantar-flexor peak torque and functional measures. By 10 weeks post-immobilization, peak torque, fatigue resistance, and all measures of functional performance had returned to control levels. Conclusion and Discussion. The decrease in muscle performance, functional ability, and fatigue resistance induced by 8 weeks of cast immobilization can be reversed with 10 weeks of supervised physical therapy. In addition, this study demonstrated that ankle-plantar flexor torque is a good predictor of stair-climbing and walking performance in patients with ankle fractures.

Below the knee amputation after trauma is an appropriate option for many patients with recalcitrant infection and nonunion of the tibia. Patients who have had transtibial amputations have lower energy expenditure, heart rate, and oxygen cost when ambulating with their prostheses than when using a three-point gait with crutches without their artificial limb. Innovative prosthetists have improved each of the five essential components of the limb amputated below the knee: socket, insert, shaft and pylon, foot and ankle assembly, and suspension system. Prosthetists are integral members of the patient's healthcare team. Their recommendations and direct patient care are essential to optimizing the functional ability of patients who have had amputations.

To evaluate the interobserver and intraobserver agreement for both treatment plan and fracture classification of tibial plateau fractures using plain films alone and with computed tomography (CT) scans.Prospective study to assess the impact of an advanced radiologic study on the agreement of treatment plan and fracture classification of tibial plateau fractures.Two orthopaedic traumatologists, two orthopaedic residents, and two skeletal radiologists were presented with twenty-one cases of tibial plateau fractures imaged with plain films and with CT scans.Agreement was measured using kappa coefficients.Using plain films alone, the mean interobserver kappa coefficient for classification was 0.62, which decreased to 0.61 after addition of CT scans. Using plain films alone for formulating a treatment plan, the mean interobserver kappa coefficient was 0.58, which increased to 0.71 after addition of CT scans. The mean intraobserver kappa coefficient for fracture classification using plain films was 0.70, which increased to 0.80 with addition of CT scans. The mean intraobserver kappa coefficient for treatment plan based on plain films alone was 0.62, which increased to 0.82 after addition of CT scans. Class was changed in an average of 12 percent of cases after addition of CT scans. Treatment plan was changed an average of 26 percent of the time after addition of CT scans.Addition of CT scans to plain roentgenograms increases the interobserver and intraobserver agreement on treatment plan.

In addition to consultation with an experienced hematologist, the following are recommendations regarding compartment syndrome in a patient with an inherited bleeding disorder. Von Willebrand's Disease. Humate-P (rich in von Willebrand factor) is the replacement therapy of choice for surgical procedures in patients with von Willebrand's disease. In general, in the perioperative period, factor VIII levels between 50% and 100% are ideal with a gradual tapering to maintain levels at 50% for approximately 2 weeks. Adjuncts to therapy are DDAVP and EACA. Hemophilia A. During the initial evaluation and with measurement of compartment pressures, factor VIII replacement to levels in the range of 40% to 60% of normal is appropriate replacement therapy. For fasciotomy, however, factor VIII levels greater than 50% to 100% are required. In patients who have developed antibodies to factor VIII, a number of options are available. With low titers of factor VIII inhibitor, higher doses of factor VIII may be successful in overriding the inhibitor. In patients with higher titers of inhibitor, activated factor VII or porcine factor VIII is recommended. Hemophilia B. Highly purified factor IX replacement aimed at keeping factor levels between 50% and 100% in the perioperative period, followed by maintenance at 50% for approximately 2 weeks, is optimal management. Treatment Algorithm: The Figure outlines an algorithm to aid in the diagnosis and treatment of compartment syndrome in the patient with an inherited bleeding disorder. In a suspected case of compartment syndrome due to a soft-tissue hemorrhage or injury, factor replacement as outlined above should be initiated. Unequivocal clinical findings in the normal patient usually would be an indication to proceed to fasciotomy without obtaining compartment pressures. In the patient with an inherited bleeding disorder, however, factor replacement and subsequent normalization of the clotting cascade may help lowe compartment pressures. Therefore, we advocate obtaining initial pressures even with clinical findings of an acute compartment syndrome. At our institution, we advocate using an automated handheld pressure monitor (Stryker, Ontario, Canada) or the needle injection technique as described by Whitesides et al. In interpreting the obtained pressures, we choose to use the guidelines as described by Heppenstall et al. Briefly, Heppenstall et al determined that the pressure threshold at which cellular damage occurred was related more closely to the difference between the mean arterial blood pressure and compartment pressure than with the absolute compartment pressure alone; this measurement is called delta P. If delta P is > 30 mm Hg, then one should continue factor replacements and perform serial clinical and pressure examinations. Pressures should be taken every hour for 2 hours total. If the patient worsens in either respect, then the physician should enter the other limb of the algorithm for delta P < 30 mm Hg. For the patient with a delta P < 30 mm Hg, the amount of time since onset of symptoms must be considered. Since the patient may improve with adequate factor replacement, a delta P < 30 mm Hg mercury does not dictate automatic fasciotomy. An adequate time trial of replacement therapy may be attempted. In patients whose pressures do not begin normalizing, we advocate proceeding to fasciotomy. Patients who begin to normalize pressures during a 2-hour trial can be followed with serial clinical and pressure examinations. Any worsening in either scenario is an indication for fasciotomy; otherwise, observation and factor replacement may be continued. After initial decompression, staples may be placed in both wound edges with an elastic vascular loop woven between the two edges in a "shoelace" pattern. Then while waiting for closure, the loops can be gradually tightened at the bedside. Definitive closure should be attempted around the fifth postoperative day. All closure techniques should be pre

The menisci are crescent-shaped fibrocartilaginous tissues which function to transmit and distribute complex loading patterns between the femur and tibia of the knee joint. Meniscus function in tension arises from highly aligned collagen fibers which run in a circumferential manner between insertion sites on the tibial plateau (1,2). However, the meniscus is often injured, and partial removal of the meniscus represents the most commonly performed orthopaedic surgery, despite the fact that its removal increases the likelihood of osteoarthritis in the long-term (3). Tissue engineered scaffolds have emerged as a promising alternative to replace portions of the damaged meniscus (4). Toward replacement, we have developed aligned nanofibrous scaffolds that can recapitulate the mechanical anisotropy of the meniscus (5,6). More recently, we have developed an approach to replicate the circumferential macroscopic orientation of fibers using a novel electrospinning method (7). However, these organized scaffolds are relatively thin (

The risk of transmission of blood-borne pathogens is directly related to the prevalence of the infectious disease in the physician's patient population, the infectivity after a single exposure, and the frequency and nature of exposure. After reading this material the reader should understand the guidelines for risk prevention of human immunodeficiency virus (HIV), hepatitis B virus, and hepatitis C virus transmission as published by the Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration (OSHA) and be better able to evaluate and choose personal protective devices for use while caring for patients. To date there have been no documented cases of HIV seroconversion from solid-bore needle puncture or aerosolized transmission from an HIV-positive patient to a physician in the operating room. However, the authors and the Orthopaedic Trauma Association urge all physicians who have sustained an occupational seroconversion to communicate with the CDC so that prevention guidelines and health-care worker protection can be improved. Regardless, all physicians performing invasive procedures must reevaluate their techniques to determine what procedures can be modified or new instruments developed to reduce the risk of exposure.

Endogenous repair of fibrous connective tissues is limited, and there exist few successful strategies to improve healing after injury. As such, new methods that advance repair by promoting cell growth, extracellular matrix (ECM) production, and tissue integration would represent a marked clinical advance. Using the meniscus as a test platform, we sought to develop an enzyme-releasing scaffold that enhances integrative repair. We hypothesized that the high ECM density and low cellularity of native tissue present physical and biological barriers to endogenous healing, and that localized collagenase treatment might expedite cell migration to the wound edge and tissue remodeling. To test this hypothesis, we fabricated a delivery system in which collagenase was stored inside electrospun poly(ethylene oxide) (PEO) nanofibers and released upon hydration. In vitro results showed that partial digestion of the wound interface improved repair by creating a microenvironment that facilitated cell migration, proliferation and matrix deposition. Specifically, treatment with high-dose collagenase led to a 2-fold increase in cell density at the wound margin and a 2-fold increase in integrative tissue compared to untreated controls at 4 weeks (P≤0.05). Furthermore, when composite scaffolds containing both collagenase-releasing and structural fiber fractions were placed inside meniscal tears in vitro, enzyme release acted locally and resulted in a positive cellular response similar to that of global treatment with aqueous collagenase. This innovative approach to targeted enzyme delivery may aid the many patients that exhibit meniscal tears by promoting integration of the defect, thereby circumventing the pathologic consequences of partial meniscus removal, and may find widespread application in the treatment of injuries to a variety of dense connective tissues.

We report six cases where significant postoperative pain persisted in individuals following arthroscopic surgery augmented with the use of lasers. Subsequent magnetic resonance images showed lesions with signal changes compatible with the diagnosis of osteonecrosis in areas directly addressed with laser energy.

The fibrous tissues prevalent throughout the body possess an ordered structure that underlies their refined and robust mechanical properties. Engineered replacements will require recapitulation of this exquisite architecture in three dimensions. Aligned nanofibrous scaffolds can dictate cell and matrix organization; however, their widespread application has been hindered by poor cell infiltration due to the tight packing of fibers during fabrication. Here, we develop and validate an enabling technology in which tunable composite nanofibrous scaffolds are produced to provide instruction without impediment. Composites were formed containing two distinct fiber fractions: slow-degrading poly(ε-caprolactone) and water-soluble, sacrificial poly(ethylene oxide), which can be selectively removed to increase pore size. Increasing the initial fraction of sacrificial poly(ethylene oxide) fibers enhanced cell infiltration and improved matrix distribution. Despite the removal of >50% of the initial fibers, the remaining scaffold provided sufficient instruction to align cells and direct the formation of a highly organized ECM across multiple length scales, which in turn led to pronounced increases in the tensile properties of the engineered constructs (nearly matching native tissue). This approach transforms what is an interesting surface phenomenon (cells on top of nanofibrous mats) into a method by which functional, 3D tissues (>1 mm thick) can be formed, both in vitro and in vivo. As such, this work represents a marked advance in the engineering of load-bearing fibrous tissues, and will find widespread applications in regenerative medicine.

The menisci are crescent-shaped fibrocartilaginous tissues whose structural organization consists of dense collagen bundles that are locally aligned but show a continuous change in macroscopic directionality. This circumferential patterning is necessary for load transmission across the knee joint and is a key design parameter for tissue engineered constructs. To address this issue we developed a novel electrospinning method to produce scaffolds composed of circumferentially aligned (CircAl) nanofibers, quantified their structure and mechanics, and compared them with traditional linearly aligned (LinAl) scaffolds. Fibers were locally oriented in CircAl scaffolds, but their orientation varied considerably as a function of position (P0.05). LinAl fibers did not change in orientation over a similar length scale (P0.05). Cell seeding of CircAl scaffolds resulted in a similar cellular directionality. Mechanical analysis of CircAl scaffolds revealed significant interactions between scaffold length and region (P0.05), with the tensile modulus near the edge of the scaffolds decreasing with increasing scaffold length. No such differences were detected in LinAl specimens (P0.05). Simulation of the fiber deposition process produced "theoretical" fiber populations that matched the fiber organization and mechanical properties observed experimentally. These novel scaffolds, with spatially varying local orientations and mechanics, will enable the formation of functional anatomic meniscus constructs.

The menisci are crescent-shaped fibrocartilaginous tissues which function to transmit and distribute loads between the femur and tibia of the knee joint. As such, the meniscus experiences complex loads, including tension, compression, and shear. Meniscus function in tension arises from an organized microstructure — bundles of highly aligned collagen circumnavigate the tissue between insertion sites on the tibial plateau (1). These aligned collagen bundles endow the tissue with mechanical properties that are highly anisotropic, and highest in the primary collagen orientation (2). Commercial products to replace the meniscus lack this unique structure and organization (3,4). To address engineering the knee meniscus, we have developed aligned nanofibrous scaffolds that can recapitulate this mechanical anisotropy (5,6). However promising, fibers within these scaffolds are unidirectional, while the fibers within the native tissue have a pronounced c-shaped macroscopic organization. To mimic this macroscopic orientation, we developed a new electrospinning method to collect organized fibers on a planar spinning disc (7). The objective of this study was to quantify the structure and mechanics of nanofibrous scaffolds collected using this novel technique and compare the data to aligned scaffolds obtained from a traditional electrospinning approach. We hypothesized that these circumferentially aligned (CircAl) scaffolds would behave similarly to linearly aligned (LinAl) scaffolds on short length scales, but exhibit marked differences in mechanics as the length scale increased.Copyright © 2012 by ASME

The menisci are crescent-shaped fibrocartilaginous tissues featuring highly aligned collagen arranged in a circumferential fashion to allow transmission of loads across the knee joint. To mimic this macroscopic orientation, we developed a novel electrospinning method to collect circumferentially aligned (CircAl) fibers, quantified their structure and mechanics, and compared them to linearly aligned (LinAl) scaffolds. Fiber orientation of CircAl scaffolds varied considerably as a function of position (p 0.05). Alterations in cellular alignment on a macroscopic scale were observed on the CircAl scaffolds. Mechanical analysis of the CircAl scaffolds revealed significant interactions between scaffold length and region (p 0.05). In conclusion, we developed electrospun nanofibrous scaffolds with a spatially varying macroscopic fiber orientation, creating a gradient in fiber alignment and differences in tensile properties over a macroscopic scale. These organized nanofibrous scaffolds can potentially direct the formation of an anatomic meniscus construct with structure and function that vary across a large anatomic expanse.

This study was designed to determine the outcome of implemented guidelines for venous thromboembolism (VTE) prophylaxis.This study was a retrospective review of a series of consecutive blunt orthopaedic trauma patients with thromboembolic complications. The patients were compared to control subjects over the same 10-year period. Univariate and multivariate statistical methods were used to determine the odds of VTE in the setting of this management guideline and risk factors for thromboembolic complications that may be refractory to this strategy.In the 10 years following institution of clinical management guidelines at our institution, the rate of VTE events was 3.2%, and the rate of pulmonary embolus was 0.3%. Risk factors for VTE that were refractory to our clinical management guidelines were pelvic fractures, major lower extremity injury, greater than 3 days of mechanical ventilation, increasing injury severity, and spinal cord injury.The implementation of a clinical management strategy for decreasing the incidence of VTE in blunt trauma patients and other potentially preventable complications is essential. Our data suggest that patients with certain injuries are particularly at risk for VTE and warrant special attention in clinical management and risk stratification, despite effective clinical management guidelines.

Electrospun scaffolds hold promise for the regeneration of dense connective tissues, given their nanoscale topographies, provision of directional cues for infiltrating cells and versatile composition. Synthetic slow-degrading scaffolds provide long-term mechanical support and nanoscale instructional cues; however, these scaffolds suffer from a poor infiltration rate. Alternatively, nanofibrous constructs formed from natural biomimetic materials (such as collagen) rapidly infiltrate but provide little mechanical support. To take advantage of the positive features of these constructs, we have developed a composite scaffold consisting in both a biomimetic fiber fraction (i.e., Type I collagen nanofibers) together with a traditional synthetic (i.e., poly-[e-caprolactone], PCL) fiber fraction. We hypothesize that inclusion of biomimetic elements will improve initial cell adhesion and eventual scaffold infiltration, whereas the synthetic elements will provide controlled and long-term mechanical support. We have developed a method of forming and crosslinking collagen nanofibers by using the natural crosslinking agent genipin (GP). Further, we have formed composites from collagen and PCL and evaluated the long-term performance of these scaffolds when seeded with mesenchymal stem cells. Our results demonstrate that GP crosslinking is cytocompatible and generates stable nanofibrous type I collagen constructs. Composites with varying fractions of the biomimetic and synthetic fiber families are formed and retain their collagen fiber fractions during in vitro culture. However, at the maximum collagen fiber fractions (20%), cell ingress is limited compared with pure PCL scaffolds. These results provide a new foundation for the development and optimization of biomimetic/synthetic nanofibrous composites for in vivo tissue engineering.

Background: Debridement and irrigation (D&I) of open tibia fractures less than 6 hours from the time of injury has been promoted as orthopaedic dogma despite limited evidence. The goal of this study was to determine the duration between emergency room presentation and D&I in open tibia fractures and to examine factors associated with delay in treatment. Methods: The National Trauma Data Bank Version 3.0 identified 6099 blunt trauma patients with open tibia fractures. Time was calculated from emergency room arrival to first D&I. Risk factors associated with delay in treatment greater than 6 hours and greater than 24 hours were then calculated using univariate and multivariate statistical methods. Results: Median time to D&I was 4.9 hours. Forty-two percent of patients with open tibia fractures experienced a delay in treatment of greater than 6 hours and 24% of patients experienced a delay to treatment of greater than 24 hours. Risk factors associated with greater than 6- and 24-hour delay on univariate and multivariate logistic regression were age, head or thoracic injury with Abbreviated Injury Score greater than 2, and presentation between 6 pm and 2 am. Level I and university hospitals carry a greater risk of delay that was independent of injury severity in multivariate analysis. Conclusions: A significant percentage of patients with open tibia fractures undergo their first surgical intervention of D&I greater than 6 hours after presentation to the emergency room. Patients with delayed D&I have more severe injuries, are treated at university or Level I centers, and present later in the day.

Obesity is prevalent in the developed world and is associated with significant costs to the health care system. The effect of morbid obesity in patients operatively treated for long-bone fractures of the lower extremity is largely unknown. The National Trauma Data Bank was accessed to determine if morbidly obese patients (body mass index >40) with lower extremity fractures have longer length of hospital stay, higher cost, greater rehabilitation admission rates, and more complications than nonobese patients. We identified patients with operatively treated diaphyseal femur (6920) and tibia (5190) fractures. Polytrauma patients and patients younger than 16 years were excluded. Morbidly obese patients were identified by ICD-9 and database comorbidity designation (femur, 131 morbidly obese; tibia, 75 morbidly obese). Patients meeting these criteria who were not morbidly obese were used as controls. Sensitivity analyses were performed to analyze patients with isolated trauma to the tibia or femur. Morbidly obese patients were more likely to be admitted to a subacute facility. Length of stay trended higher in morbidly obese patients. There was no significant relationship between obesity and inpatient mortality or inpatient complications. These trends held true when considering patients with multiple injuries and patients who had isolated long-bone injuries. Our study showed that morbidly obese patients may have greater rehabilitation needs following long-bone fractures in the lower extremity. Our study showed no difference in mortality or complications, although further studies are needed to confirm these findings.

Fragility fractures of the distal femur pose a challenge for stable internal fixation and good functional outcomes. Among those challenges are frailty of the elderly patient, high degree of osteoporosis, instability of the fracture patterns, short distal femur segment, and amount of comminution. Mortality at 1 year has been reported as high as 30%. Morbidity includes significant decreases in function, quality of life as well as medical and surgical complications. Medical stabilization and optimization are extremely important in this frail population. Non-surgical management is reserved for minimally displaced fractures in the patient who will likely not tolerate the risks of anesthesia or surgical intervention. Surgical treatment, which is the favored treatment, is necessary to prevent prolonged immobilization and its sequelae. Surgical treatment options include antegrade or retrograde intramedullary nailing, standard lateral plating, the use of fixed angle devices, and total knee arthroplasty. Rehabilitation is necessary and includes early range of motion, strengthening, mobilization, gait training if possible, and prevention of common medical complications.

Background: Comorbidities before and complications following hip fracture surgery can impact the return of function. We hypothesized that the American Society of Anesthesiologists (ASA) classification of medical comorbidities is a useful surrogate variable for the patient's general medical condition and would be a strong predictor of perioperative medical complications following hip fracture surgery. Methods: A retrospective review of the cases of 197 elderly patients who had undergone operative management of a hip fracture was performed. The ASA class, data regarding perioperative medical and surgical complications, and demographic data were obtained. Medical complications were defined as those requiring intervention by an internist or medical specialist. Differences in complication rates among the ASA classes were determined. Results: Medical complications were more common in patients in ASA class 3 (p < 0.001) and those in class 4 (p = 0.001) than in those in class 2. Patients in ASA class 3 had a 3.78 times greater chance of having a medical complication than did those in class 2 (p < 0.001). Patients in ASA class 4 had a 7.39 times greater chance of having medical complications than did those in class 2 (p = 0.001). No significant relationship was identified between the ASA class and surgical complications. Conclusions: The ASA class is strongly associated with medical problems in the perioperative period following hip fracture surgery in the elderly. Patients identified as being at higher risk (in ASA class 3 or 4) preoperatively should be closely managed medically so that perioperative medical complications can be managed and evolving medical issues can be addressed in a timely fashion. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Definitive treatment of open fractures of the tibial diaphysis is challenging. The high-energy nature of these fractures, as well as the contamination of the fracture site and devitalization of the soft-tissue envelope, greatly increases the risk of infection, nonunion, and wound complications. The goals of definitive treatment include wound coverage or closure; prevention of infection; restoration of length, alignment, rotation, and stability; fracture healing; and return of function. Advances in orthobiologics, modern plastic surgical techniques, and fracture stabilization methods, most notably locked intramedullary nailing, have led to improved prognosis for functional recovery and limb salvage. Despite improved union and limb salvage rates, the prognosis for severe type III open fracture of the tibial shaft remains guarded, and outcomes are often determined by patient psychosocial variables.

Compartment syndrome is a devastating complication of tibial fractures. The purpose of this study was to investigate the rate of clinically determined compartment syndrome requiring surgical intervention in tibial fractures by anatomical region and to identify the associated patient and injury factors.Retrospective cohort.University level I trauma center.Acute tibial fractures in 414 patients from January 1, 2004 through October 31, 2006.Tibial fractures in 414 patients met the inclusion and exclusion criteria. The fractures were classified into 3 groups (proximal, diaphyseal, and distal) based on the anatomic location of the fractures (AO/OTA fractures 41, 42, and 43, respectively). To determine the patient and injury factors associated with the development of compartment syndrome in tibial fractures, the following data were obtained: patient age and sex, mechanism of injury, presence of associated fractures, presence of concomitant head/chest/abdominal/pelvic injury, blood pressure upon admission, open versus closed fracture (Gustilo-Anderson classification if open), status of the fibula, and AO/OTA classification of the tibial fracture.Rate of clinically determined compartment syndrome requiring fasciotomy by anatomical region of the tibia.The rate of compartment syndrome was highest in the diaphyseal group (8.1%, P0.05) followed by proximal (1.6%) and distal (1.4%) groups. The diaphyseal group was further analyzed according to patient and injury factors. Patients who developed compartment syndrome were significantly younger (27.5 years +/- 11.7 SD versus 39.0 years +/- 16.7 SD, P = 0.003, Student t test) than those who did not develop compartment syndrome. The mean arterial pressures upon admission of the patients who developed compartment syndrome were also found to be slightly higher (107 versus 98.5 mm Hg, P = 0.039, Student t test) but not significantly so after Bonferroni adjustment. In multivariate regression analysis, decreasing age remained the only statistically significant independent predictor for the development of compartment syndrome (P = 0.006, regression coefficient = -0.0589) in diaphyseal tibial fractures.Tibial fractures of the diaphysis are more frequently associated with development of compartment syndrome than proximal or distal tibial fractures. More specifically, young patients with diaphyseal fractures are at risk for developing this complication and warrant increased vigilance and suspicion for compartment syndrome. A prospective study with sufficient power is needed to further identify risk factors associated with compartment syndrome in tibial fractures.

The orthopedist's goals are to prevent wound infection, expedite fracture healing, and restore optimal function. The importance of the soft tissue envelope to fracture healing is well recognized. In spite of continual research concerning wound repair, we remain at a loss to define precisely what starts the wound healing process and what ultimately stops it. In this article, we consider the basic science of wound repair, the effects of the patient's nutrition and volume status, soft tissue wound dressing options, soft tissue transfers, and specific recommendations.

This article presents an overview of the toxicities associated with the antibiotics more commonly used for the treatment of osteomyelitis. Included in each drug monograph are major and minor side effects, significant drug-drug and drug-food interactions, and the relative safety of the antimicrobial during pregnancy and in breast-feeding women.

The sensitivity, specificity, and predictive value of magnetic resonance imaging in the diagnosis of lesions of the rotator cuff, glenohumeral capsule, and glenoid labrum were evaluated in ninety-one patients and fifteen asymptomatic volunteers. Magnetic resonance imaging demonstrated 100 per cent sensitivity and 95 per cent specificity in the diagnosis of complete tears, and it consistently predicted the size of the tear of the rotator cuff. There was a definite correlation between atrophy of the supraspinatus muscle and the size of a complete, chronic tear of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the differentiation of tendinitis from degeneration of the cuff were 82 and 85 per cent, and in the differentiation of a normal tendon from one affected by tendinitis with signs of impingement the sensitivity and specificity were 93 and 87 per cent. The formation of spurs around the acromion and acromiocalvicular joint correlated highly with increased age of the patient and with chronic disease of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the diagnosis of labral tears associated with glenohumeral instability were 88 and 93 per cent. The study showed that high-resolution magnetic-resonance imaging is an excellent non-invasive tool in the diagnosis of lesions of the rotator cuff and glenohumeral instability.

Although hemiarthroplasties are an important treatment for femoral neck fractures, the literature does not provide a clear approach for selecting the implant fixation method. Therefore, we performed a systematic search of the medical literature and identified 11 prospective and retrospective studies that compared results between cemented and uncemented femoral implant fixation methods. After independent blind data extraction, we compared variables between cemented and uncemented cohorts using two different meta-analysis models. Pooled data represented 1632 cemented and 981 uncemented hemiarthroplasties (average age of patients, 78.9 and 77.5 years, respectively). The average operating room times and blood loss volumes were 95 minutes and 467 mL, respectively, for the cemented and 80 minutes and 338 mL for the uncemented cohorts. Postoperative mortality rates, overall complications, and pain were similar between the two cohorts. Despite a few potential trends, we found few statistical differences between cemented and uncemented techniques based on reported outcome measurements. In addition, inspection of this literature underscored the lack of and need for consistent and standardized reporting of outcome variables regarding these procedures.

Background: The use of recombinant human bone morphogenetic protein-2 (rhBMP-2) to improve the healing of open tibial shaft fractures has been the focus of two prospective clinical studies. The objective of the current study was to perform a subgroup analysis of the combined data from these studies. Methods: Two prospective, randomized clinical studies were conducted. A total of 510 patients with open tibial fractures were randomized to receive the control treatment (intramedullary nail fixation and routine soft-tissue management) or the control treatment and an absorbable collagen sponge impregnated with one of two concentrations of rhBMP-2. The rhBMP-2 implant was placed over the fracture at the time of definitive wound closure. For the purpose of this analysis, only the control treatment and the Food and Drug Administration-approved concentration of rhBMP-2 (1.50 mg/mL) were compared. Patients who anticipated receiving planned bone-grafting as part of a staged treatment were excluded from enrollment. Results: Fifty-nine trauma centers in twelve countries participated, and patients were followed for twelve months postoperatively. Two subgroups were analyzed: (1) the 131 patients with a Gustilo-Anderson type-IIIA or IIIB open tibial fracture and (2) the 113 patients treated with reamed intramedullary nailing. The first subgroup demonstrated significant improvements in the rhBMP-2 group, with fewer bone-grafting procedures (p = 0.0005), fewer patients requiring invasive secondary interventions (p = 0.0065), and a lower rate of infection (p = 0.0234), compared with the control group. The second subgroup analysis of fractures treated with reamed intramedullary nailing demonstrated no significant difference between the control and the rhBMP-2 groups. Conclusions: The addition of rhBMP-2 to the treatment of type-III open tibial fractures can significantly reduce the frequency of bone-grafting procedures and other secondary interventions. This analysis establishes the clinical efficacy of rhBMP-2 combined with an absorbable collagen sponge implant for the treatment of these severe fractures. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Healthcare Failure Mode and Effects Analysis (HFMEA) is a methodology for correcting latent system errors before they lead to adverse events. We examined the utility of HFMEA in evaluating the sterilization and use of surgical instruments. First, a multidisciplinary team graphed the process in a flow diagram. A hazard analysis was then used to examine potential failure modes (i.e., ways in which a process can fail) and their causes and to score the severity and other factors for each failure mode cause. Actions were then planned to address the selected failure mode causes. Flow charts were created for 3 foci: sterilization process, reading of biologicals, and use of equipment. Information was gathered through interviews and a review of the literature. Multiple clinically significant system errors were identified, and actions to correct them were developed. The HFMEA methodology facilitated the detection of previously unrecognized system errors, demonstrating its potential utility in addressing healthcare epidemiology-related adverse events.

Musculoskeletal infections result in considerable morbidity and mortality and lead to prolonged hospitalization and increased healthcare costs. Such infections present a major challenge to patients, treating teams of specialists, and healthcare systems. An improved understanding of prevention, diagnosis, and treatment of these infections is essential to enhance patient care and outcomes. With this goal in mind, the 20th annual meeting of the Musculoskeletal Infection Society of North America was held in Marina Del Rey, CA, in August 2010. The meeting included educational lectures and research papers on basic and biofilm science; risk factors; and prevention, diagnosis, and treatment of musculoskeletal infections. In this issue, Clinical Orthopaedics and Related Research features 11 of these papers. Four papers focus on the basic science of local antimicrobial delivery. New information is presented on elution of antimicrobials from emulsified bone cement, from bone cement of increased porosity, and from two sources of calcium sulfate as delivery vehicles. The cytotoxic effects of amphotericin B are also demonstrated. Diagnosis of infection can be challenging, and three papers address this issue by describing the role of joint aspirate white blood cell count and neutrophil percentage in the diagnosis of periprosthetic joint infections, by investigating the association of early postoperative leukocytosis with these infections, and by presenting a novel molecular technique for the diagnosis of infection. Two papers report on the management of periprosthetic joint infections. The results of irrigation and debridement for these infections are presented, as well as the outcome after two-stage exchange arthroplasty for infected knee arthroplasty. Finally, one paper addresses septic arthritis of a diseased hip using an articulating spacer and one reports on the sterility of the personal protection system in total joint arthroplasty. The annual meeting of the Musculoskeletal Infection Society of North America emphasizes interdisciplinary collaboration among basic scientists, infectious disease specialists, and orthopaedic surgeons and provides a unique opportunity to exchange information and learn from each other. The 2-day meeting in 2011 was held in Rochester, MN, August 5 to 6 (Figs. 1, ​,22). Fig. 1 Dr. Charalampos G. Zalavras is shown. Fig. 2 Dr. Montri D. Wongworawat is shown.