Modernizing Our Understanding of Total Hip Arthroplasty in the Pediatric and Young Adult Patient: A Single-center Experience.

INTRODUCTION: Pediatric hip disorders represent a broad range of pathology and remain a significant source of morbidity for children and young adults. Surgical intervention is often required for joint preservation, but when salvage is not possible, joint replacement may be indicated to eliminate pain and preserve function. Although there have been significant updates in the management of both pediatric hip disease and the field of total hip arthroplasty (THA), there is a paucity of literature reflecting advancements in the area of pediatric and young adult (PYA) arthroplasty. No study has investigated the impact of approach on outcomes after PYA THA. The purpose of this study is to describe the indications, techniques, and early outcomes of THA in the PYA population in a modern practice setting. METHODS: We performed a retrospective descriptive analysis of all patients undergoing primary THA performed at a tertiary care children's hospital from 2004 to 2019. Ninety-three hips in 76 patients were evaluated. Demographics, intraoperative variables, postoperative pain and function ratings, and complication and revision rates were collected. RESULTS: Eighty-five hips in 69 patients were included. Patients were aged 12 to 23 years old, with males and females represented equally (33 vs. 36, respectively). The most common cause of hip pain was avascular necrosis (AVN, 56/85, 66%), most commonly due to slipped capital femoral epiphysis (13/56, 23%) idiopathic AVN (12/56, 21%), and chemotherapy (12/56, 21%). Half of all hips had been previously operated before THA (43/85). Thirty-six procedures were performed via the posterolateral approach (36/85, 42%), 33 were performed via direct anterior approach (33/85, 39%), and 16 were performed via the lateral approach (LAT, 16/85, 19%). At final follow-up, 98% (83/85) of patients had complete resolution of pain, 82% (70/85) had no notable limp, and 95% (81/85) had returned to all activities. There were 6 complications and 1 early revision. Average Hip disability and Osteoarthritis Outcomes Score for Joint Replacement scores increased by 37 points from 56 to 93. The overall revision-free survival rate for PYA THA was 98.8% (at average 19-mo follow-up). CONCLUSIONS: Modern PYA THA is dissimilar in indications and surgical techniques to historic cohorts, and conclusions from prior studies should not be generalized to modern practice. In our practice, PYA patients most commonly carry a diagnosis of AVN, and THA can be performed with modern cementless fixation with large cup and head sizes and ceramic-on-cross-linked polyethylene bearings utilizing any approach. Further study is required to better characterize middle-term and long-term results and patient-reported outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV-retrospective case series.

Triple Surgical Fixation Technique for an Isolated Greater Trochanter Fracture in an Amateur Weightlifter.

Isolated greater trochanter fractures have been infrequently described in the literature and are typically managed conservatively. Functional strength after injury to the abductor complex can be markedly affected resulting in a Trendelenburg gait and overall abductor weakness. We present a case of a 35-year-old athlete who underwent surgical fixation because of notable fracture displacement and function debility. This case vignette demonstrates the importance of using all available interdisciplinary orthopaedic surgery literature to provide a patient-specific surgical construct. Our patient benefitted from arthroscopic, arthroplasty, and trauma evidence-based medicine to successfully treat his displaced greater trochanteric hip fracture. Successful surgical fixation was enhanced by combining three different methods of fixation: osteosynthesis with partially threaded screws and washers (DePuy Synthes), suture anchor (Arthrex) direct fracture approximation and tendon reinforcement, and a knotless double-row suture bridge (Arthrex) tension band construct. The patient was able to return weightlifting at 4 months postoperatively with no evidence of weakness or trendelenburg gait.

Factors, treatments, and outcomes associated with primary soft tissue malignancies of the forearm: A series of 31 cases.

BACKGROUND: Primary soft tissue malignancies of the forearm constitute up to 24% of soft tissue extremity malignancies and present a difficult problem when attempting to preserve both life and forearm function. As described by Enneking, recurrence and metastasis are the two largest contributors to morbidity and mortality and therefore, the primary consideration must be to excise the entire tumor. However, since limb salvage is the preferred treatment over amputation in 95% of cases, many physicians elect to perform marginal resections over wide resections in the attempt to increase functional outcomes. Our study aimed to compare recurrence rates and forearm functional outcomes between these groups to better guide clinical decision making. QUESTIONS/PURPOSES: (1) What is the difference in recurrence rates between wide resection of the tumor and marginal resection? (2) Between wide and marginal resection groups, what is the functional difference as measured by MSTS functional outcome scores? The purpose of our study was to answer these two questions and better understand if marginal resection yielded better results compared to wide resection. PATIENTS AND METHODS: Following IRB approval, we conducted a retrospective case series between 1999 and 2019. Included in the study were patients with a primary malignancy in the predetermined borders of the forearm with a minimum of two-year follow up post-operatively. All patients in the study were operated on by physicians in the Southern California Kaiser Permanente system. Thirty-one patients met criteria for the study. Recurrence rates and metastatic disease was determined through serial history and physical examination, with patients undergoing magnetic resonance (MRI) imaging of the affected area and computed tomography (CT) of the chest every 6 months for the first 2 years, and every 12 months for the following 3 years. MSTS scores were obtained in subsequent follow-ups following the guidelines set by the MSTS scoring system. RESULTS: Of the 31 patients evaluated, 4 (12.9%) had recurrence and 2 (6.5%) had signs of metastasis. Between the marginal excision and wide excision groups, all 4 recurrences happened in the marginal excision group and none occurred in the wide excision group. In addition, in the pathology report, excisions with 0.1 cm margins or less on any side had 3 instances of recurrence (31%) whereas there was only 1 recurrence (4.8%) outside of this group. MSTS scores for both wide excision and marginal excision were within 1 point with average scores being 26 and 26.9, respectively. CONCLUSIONS: Consistent with the literature, our study found that closer surgical margins lead to higher rates of recurrence due to the increased likelihood of aberrant tumor. However, when looking at functional outcome scores, we found minimal benefit in marginal resections compared to wide resections. The lack of MSTS score difference between both groups highlighted that the perceived benefit of choosing a marginal resection over wide excision may be nominal at best. Therefore, we recommend performing an additional intraoperative resection on narrow margins to reduce the chance of recurrence. Of note, clinical discernment in the form of preserving valuable neurovascular structures such as the median nerve should still be an important consideration.

Primary Knee Intra-articular Synovial Sarcoma in Pediatric and Adolescent Patients.

Synovial sarcoma (SS) arising within a knee joint is extremely rare, with 10 reported cases in pediatric and adolescent patients in English literature. Its rarity and nonspecific clinical and radiological features pose a diagnostic challenge. We present two cases of primary intra-articular SS of left knee to enhance awareness of this entity. One patient is a 17-year-old male complained of left knee pain and gait abnormality for 9 years. The other one is a 13-year-old female presented with left knee pain for one year. Both cases were clinically diagnosed as benign joint lesion and underwent biopsies. Histological examination, immunohistochemical staining and molecular study confirmed that both patients had primary intra-articular SS, monophasic spindle cell type. Intraarticular SS should be considered as a potential diagnosis with unexplained long-standing knee pain.

The WaterHub at Emory University: Campus Resiliency through Decentralized Reuse.

In the spring of 2015, Emory University in Atlanta, GA, commissioned an innovative campuswide water reclamation and reuse system known as the WaterHub®. Treating up to 400,000 gallons each day, the system can recycle the equivalent of two-thirds of the University's wastewater production and reduce the campus water footprint by up to 40 percent.One of the first district-scale water reuse systems in North America, the WaterHub mines wastewater from the campus sewer system and repurposes it for beneficial reuse on campus. In its first year of operation, the facility has treated more than 80 million gallons of campus wastewater and is expected to save millions of dollars in utility costs for the University over the next 20 years. The system represents a new age in commercial-scale water management in which onsite, urban water reclamation facilities may be a new norm.

Decoding the Epigenetic Heterogeneity of Human Pluripotent Stem Cells with Seamless Gene Editing.

Pluripotent stem cells exhibit cell cycle-regulated heterogeneity for trimethylation of histone-3 on lysine-4 (H3K4me3) on developmental gene promoters containing bivalent epigenetic domains. The heterogeneity of H3K4me3 can be attributed to Cyclin-dependent kinase-2 (CDK2) phosphorylation and activation of the histone methyltransferase, MLL2 (KMT2B), during late-G1. The deposition of H3K4me3 on developmental promoters in late-G1 establishes a permissive chromatin architecture that enables signaling cues to promote differentiation from the G1 phase. These data suggest that the inhibition of MLL2 phosphorylation and activation will prevent the initiation of differentiation. Here, we describe a method to seamlessly modify a putative CDK2 phosphorylation site on MLL2 to restrict its phosphorylation and activation. Specifically, by utilizing dimeric CRISPR RNA-guided nucleases, RFNs (commercially known as the NextGEN™ CRISPR), in combination with an excision-only piggyBac™ transposase, we demonstrate how to generate a point mutation of threonine-542, a predicted site to prevent MLL2 activation. This gene editing method enables the use of both positive and negative selection, and allows for subsequent removal of the donor cassette without leaving behind any unwanted DNA sequences or modifications. This seamless "donor-excision" approach provides clear advantages over using single stranded oligo-deoxynucleotides (ssODN) as donors to create point mutations, as the use of ssODN necessitate additional mutations in the donor PAM sequence, along with extensive cloning efforts. The method described here therefore provides the highest targeting efficiency with the lowest "off-target" mutation rates possible, while removing the labor-intensive efforts associated with screening thousands of clones. In sum, this chapter describes how seamless gene editing may be utilized to examine stem cell heterogeneity of epigenetic marks, but is also widely applicable for performing precise genetic manipulations in numerous other cell types.

Gene Editing in Human Pluripotent Stem Cells: Choosing the Correct Path.

The recent emergence of targeted nucleases has opened up new opportunities for performing genetic modifications with human pluripotent stem cells (hPSCs). These modifications can range from the creation of a routine knock-out to the more challenging single point-mutation. For both the new and established user, deciding on the best approach for the specific modification of interest can be an arduous task, as new and improved technologies are rapidly and continuously being developed. The choices between the reagents and methodologies depends entirely on the end-goal of the experiments and the locus to be modified. Investigators need to decide on the best nuclease to use for each experiment from among Zinc-Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 that would result in the highest likelihood of success with the fewest pitfalls. Furthermore, there have been significant improvements over the first-generation nucleases, such as the development of the dimeric CRISPR RNA-guided Fok1 nucleases (RFNs, marketed as NextGEN™ CRISPR) that reduces the "off-target" mutation rate, providing further options for investigators. Should researchers need to perform a point mutation, then considerations must be made between using single-stranded oligo-deoxynucleotides (ssODN) as the donor for homology-directed repair or utilizing a selection cassette within a donor vector in combination with an excision-only piggyBac™ transposase to leave a seamless edit. In this review, we will provide a general overview of the current technologies, along with methodologies for generating point mutations, while considering both their pros and cons.

Prognostic value of necrosis after neoadjuvant therapy for soft tissue sarcoma.

BACKGROUND AND OBJECTIVES: While treatment-induced tissue necrosis is a well-documented predictor of patient survival in malignant bone tumors, its prognostic value in soft tissue sarcomas is controversial. A prior study from our institution did not find a prognostic value to tumor necrosis. We analyze a more extensive database of high-grade soft tissue sarcomas treated with neoadjuvant chemotherapy, radiation therapy, or both to re-evaluate if the degree of tumor necrosis alone can be used as a predictive factor for local recurrence, metastasis, and disease-specific survival. METHODS: Two hundred and seven patients with high-grade extremity soft tissue sarcoma received neoadjuvant chemotherapy and/or radiation therapy and wide excision. Tumor treatment response was determined by histopathologic analysis, and patients were followed for local recurrence, metastasis, or death. RESULTS: Tumor necrosis ≥ 90% correlates with improved disease-free survival with univariate analysis, but this does not reach statistical significance on multivariate analysis. Age and tumor volume were found to be the only independent predictors of disease-free survival on multivariate analysis. CONCLUSIONS: There is insufficient evidence to support the use of necrosis to prognosticate survival and alter chemoradiation regimens in high grade soft tissue sarcomas of the extremity. Larger studies are needed to definitively address the prognostic value of necrosis. LEVEL OF EVIDENCE: Level II, Prognostic

Clavicular eosinophilic granuloma causing adult shoulder pain.

Though rarely reported, neoplasms of the clavicle occur, and their symptoms can be mistaken for more common shoulder conditions. We present the case of a benign clavicular neoplasm, rarely seen in adults, presenting with pain, and eventual pathologic fracture in a 49 year-old. A 49 year-old male firefighter underwent arthroscopic rotator cuff repair for shoulder pain after magnetic resonance imaging revealed supraspinatus tendon tear. The patient's pain persisted after surgery, and was described as routine until he developed severe pain after minor blunt trauma. A local Emergency Room performed the first x-rays, which revealed a pathologic fracture of the distal clavicle through a destructive lesion. The patient was referred to an orthopedic oncologist, who performed incisional biopsy, which initially diagnosed osteomyelitis. The patient was subsequently taken to surgery for debridement. Pathology then yielded the diagnosis of eosinophilic granuloma. The patient was taken back to surgery for formal curettage with open reduction and internal fixation. The patient's pain resolved, the pathologic fracture fully healed, and the patient returned to full time work as a firefighter. Though workup for common shoulder conditions often identifies incidental benign lesions of bone, the converse can be true. Persistent pain despite intervention should raise concern for further investigation. An x-ray alone can reveal a destructive bone lesion as the source of shoulder pain.

A novel highly potent therapeutic antibody neutralizes multiple human chemokines and mimics viral immune modulation.

Chemokines play a key role in leukocyte recruitment during inflammation and are implicated in the pathogenesis of a number of autoimmune diseases. As such, inhibiting chemokine signaling has been of keen interest for the development of therapeutic agents. This endeavor, however, has been hampered due to complexities in the chemokine system. Many chemokines have been shown to signal through multiple receptors and, conversely, most chemokine receptors bind to more than one chemokine. One approach to overcoming this complexity is to develop a single therapeutic agent that binds and inactivates multiple chemokines, similar to an immune evasion strategy utilized by a number of viruses. Here, we describe the development and characterization of a novel therapeutic antibody that targets a subset of human CC chemokines, specifically CCL3, CCL4, and CCL5, involved in chronic inflammatory diseases. Using a sequential immunization approach, followed by humanization and phage display affinity maturation, a therapeutic antibody was developed that displays high binding affinity towards the three targeted chemokines. In vitro, this antibody potently inhibits chemotaxis and chemokine-mediated signaling through CCR1 and CCR5, primary chemokine receptors for the targeted chemokines. Furthermore, we have demonstrated in vivo efficacy of the antibody in a SCID-hu mouse model of skin leukocyte migration, thus confirming its potential as a novel therapeutic chemokine antagonist. We anticipate that this antibody will have broad therapeutic utility in the treatment of a number of autoimmune diseases due to its ability to simultaneously neutralize multiple chemokines implicated in disease pathogenesis.

Antibody discovery ex vivo accelerated by the LacO/LacI regulatory network.

Monoclonal antibodies (mAbs) can be potent and highly specific therapeutics, diagnostics and research reagents. Nonetheless, mAb discovery using current in vivo or in vitro approaches can be costly and time-consuming, with no guarantee of success. We have established a platform for rapid discovery and optimization of mAbs ex vivo. This DTLacO platform derives from a chicken B cell line that has been engineered to enable rapid selection and seamless maturation of high affinity mAbs. We have validated the DTLacO platform by generation of high affinity and specific mAbs to five cell surface targets, the receptor tyrosine kinases VEGFR2 and TIE2, the glycoprotein TROP2, the small TNF receptor family member FN14, and the G protein-coupled receptor FZD10. mAb discovery is rapid and humanization is straightforward, establishing the utility of the DTLacO platform for identification of mAbs for therapeutic and other applications.

A meta-analysis of osteosarcoma outcomes in the modern medical era.

Four decades ago, specialized chemotherapy regimens turned osteosarcoma, once considered a uniformly fatal disease, into a disease in which a majority of patients survive. Though significant survival gains were made from the 1960s to the 1980s, further outcome improvements appear to have plateaued. This study aims to comprehensively review all significant, published data regarding osteosarcoma and outcome in the modern medical era in order to gauge treatment progress. Our results indicate that published survival improved dramatically from 1960s to 1980s and then leveled, or in some measures decreased. Recurrence rates decreased in the 1970s and then leveled. In contrast, published limb salvage rates have increased significantly every recent decade until the present. Though significant gains have been made in the past, no improvement in published osteosarcoma survival has been seen since 1980, highlighting the importance of a new strategy in the systemic management of this still very lethal condition.

Moving beyond response criteria: new measures of success in the treatment of sarcomas.

There is an urgent need to develop new therapies for soft tissue sarcomas. Traditional cytotoxic therapies, such as doxorubicin and ifosfamide, have been the standard approach to this disease. However, newer paradigms are emerging that are less toxic while targeting dysregulated pathways, tumor hypoxia, and genetic translocations. These newer therapies require different measures of activity as standard response criteria may inaccurately measure their effectiveness. Serious consideration of select endpoints and measures of tumor response are crucial to make significant strides in the treatment of sarcomas. Current studies on soft tissue sarcomas are slowly abandoning response rates while employing progression-free survival and time to progression as improved endpoints. With time and data, our understanding of the relative activity of these agents will grow and lead to improved benefits for our patients.

Endoprostheses last longer than intramedullary devices in proximal femur metastases.

BACKGROUND: The proximal femur is the most common site of surgery for bone metastases, and stabilization may be achieved through intramedullary fixation (IMN) or endoprosthetic reconstruction (EPR). Intramedullary devices are less expensive, less invasive, and may yield improved function over endoprostheses. However, it is unclear which, if either, has any advantages. QUESTIONS/PURPOSES: We determined whether function, complications, and survivorship differed between the two approaches. METHODS: We retrospectively reviewed 158 patients with 159 proximal femur metastatic lesions treated with surgical stabilization. Forty-six were stabilized with IMN and 113 were treated with EPR. The minimum followup was 0.25 months (mean, 16 months; median, 17 months; range, 0.25-86 months). RESULTS: The mean Musculoskeletal Tumor Society score was 24 of 30 (80%) after IMN and 21 of 30 (70%) after EPR. There were 12 complications (26%) in the IMN group, including 10 nonunions, six of which went on to mechanical failure. There were complications in 20 of 113 (18%) of the EPR group, which consisted of 10 dislocations (9%) and 10 infections (9%). There were no mechanical failures with EPR. Both implants remained functional for the limited lifespan of these patients in each group at all time intervals. EPRs were associated with increased implant longevity compared with IMNs (100% versus 85% 5-year survival, respectively) and a decreased rate of mechanical failure (0% versus 11%, respectively) when compared with the intramedullary devices. CONCLUSIONS: Patients with metastatic disease to the proximal femur may live for long periods of time, and these patients may undergo stabilization with either IMN or EPR with comparable functional scores and the implant survivorship exceeding patient survivorship at all time intervals. Endoprostheses demonstrate a lower mechanical failure rate and a higher rate of implant survivorship without mechanical failure than IMN devices. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

A comparison of fine-needle aspiration, core biopsy, and surgical biopsy in the diagnosis of extremity soft tissue masses.

BACKGROUND: Biopsy tissue can be obtained through a fine needle, a wider coring needle, or through an open surgical incision. Though much literature exists regarding the diagnostic yield of these techniques individually, none compare accuracy of diagnosis in the same mass. QUESTIONS/PURPOSES: We asked how the diagnostic accuracy of fine-needle aspiration, core biopsy, and open surgical biopsy compare in regard to identifying malignancy, establishing the exact diagnosis, and guiding the appropriate treatment of soft tissue masses. PATIENTS AND METHODS: We prospectively studied 57 patients with palpable extremity soft tissue masses, performing fine-needle aspiration, followed by core biopsy, followed by surgical biopsy of the same mass. RESULTS: Open surgical biopsy was 100% accurate on all accounts. With regard to determining malignancy, fine-needle aspiration and core biopsy had 79.17% and 79.2% sensitivity, 72.7% and 81.8% specificity, 67.9% and 76% positive predictive value, 82.8% and 84.4% negative predictive value, and an overall accuracy of 75.4% and 80.7%, respectively. In regard to determining exact diagnosis, fine-needle aspiration had a 33.3% accuracy and core biopsy had a 45.6% accuracy. With regard to eventual treatment, fine-needle aspiration was 38.6% accurate and core biopsy was 49.1% accurate. CONCLUSIONS: In soft tissue mass diagnosis, core biopsy is more accurate than fine-needle aspiration on all accounts, and open biopsy is more accurate than both in determining malignancy, establishing the exact diagnosis, and the guiding appropriate treatment.

Microbiology of bone and joint infections in injecting drug abusers.

BACKGROUND: The literature contains variable reports on the causative organisms of osteomyelitis and septic arthritis in patients with injecting drug abuse and on the rate of oxacillin-resistant S aureus. It is important to have a clear notion of the organisms to initiate empiric antimicrobial therapy. QUESTIONS/PURPOSES: We therefore determined the spectrum of organisms in bone and joint infections in patients who were injecting drug users. METHODS: We retrospectively reviewed the medical records of 215 patients (154 male, 61 female) with a history of injecting drug abuse and concurrent bone and/or joint infection from 1998 to 2005. The mean age was 43 years (range, 23-83 years). Osteomyelitis was present in 127 of the 215 patients (59%), septic arthritis in 53 (25%), and both in 35 (16%). The lower extremity was most commonly involved (141 cases, 66%), with osteomyelitis of the tibia present in 70 patients (33%) and septic knee arthritis in 30 patients (14%). RESULTS: Cultures yielded predominately Gram-positive bacteria: Staphylococcus aureus in 52% and coagulase-negative Staphylococcus in 20%. The proportion of oxacillin-resistant S aureus among S aureus infections increased from 21% in 1998 to 73% in 2005. Gram-negative organisms were present in 19% of infections and anaerobes in 13%. Patients with osteomyelitis had a higher prevalence of polymicrobial infections (46% versus 15%), infections due to Gram-negative organisms (24% versus 9%), and anaerobic infections (19% versus 6%) compared to patients with septic arthritis. CONCLUSIONS: These findings suggest broad-spectrum empiric antibiotic therapy, including vancomycin, should be considered for bone and joint infections in patients with injecting drug abuse. LEVEL OF EVIDENCE: Level IV, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Periacetabular reconstruction with a new endoprosthesis.

UNLABELLED: Reconstruction of the Type II pelvic resection is challenging. Currently available reconstructive options have inherent problems including graft and implant failure, pain, poor function, and high major complication rates. The periacetabular reconstruction (PAR) endoprosthesis was designed to be secured with internal fixation and bone cement to the remaining ilium and support a reconstructed acetabulum. This construct potentially avoids the complications of graft or hardware failure, while maintaining early mobilization, comfort, limb lengths, and function. We retrospectively reviewed 25 patients who underwent Type II pelvic resection and reconstruction with the PAR endoprosthesis, analyzing function, complications, and survivorship. The minimum followup was 13 months (mean, 29.4 months; range, 13 to 108 months). We compared the PAR data with the literature for the Mark II saddle endoprosthesis. The PAR's average MSTS score was 20.8 (67%), major complications occurred in 14 (56%), and implant survivorship was 84% at 2 years and 60% at 5 years. The rate of failure at the ilium-saddle interface was lower and implant survivorship higher than those in the published literature for the Mark II saddle. We recommend use of the PAR endoprosthesis for reconstruction of large defects following Type II pelvic resection. The modified saddle design provides greater inherent stability, allowing for faster rehabilitation and improved longevity without increased complications and is an improvement over the currently available saddle prostheses. LEVEL OF EVIDENCE: Level III, retrospective case series. See Guidelines for Authors for a complete description of levels of evidence.

The linear cutting stapler may reduce surgical time and blood loss with muscle transection: a pilot study.

UNLABELLED: Because of skeletal muscle's density and vascularity, its transection with standard electrocautery can be tedious. In a pilot study we asked whether a linear cutting stapling device decreased surgical time, blood loss, transfusion rates, and complications in patients undergoing above-knee amputation when compared to traditional electrocautery. We retrospectively reviewed 11 patients with above-knee amputation cases using a linear cutting stapling device over a 10-year period and compared those to 13 patients in whom we used electrocautery. The patients treated with the linear cutting stapling device had an average of 97 minutes of surgical time, 302 cc blood loss, and 1.55 units transfusion, compared to an average 119 minutes, 510 cc, and 2.15 units, respectively, with the electrocautery cases. Despite the trends, these parameters, as well as major complications, were similar in these two small groups. In skeletal muscle transection, we believe the linear cutting stapler is a reasonable and potentially cost-effective technical alternative to electrocautery, possibly resulting in less blood loss and shorter surgical time with similar rates of complications. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Microbiology of upper extremity soft tissue abscesses in injecting drug abusers.

Drug injection often results in upper extremity soft tissue infections. We determined the bacteriology of soft tissue abscesses in substance abusers who inject drugs to provide guidelines for empiric antibiotic therapy. We retrospectively studied 855 patients (638 men and 217 women; mean age, 41.5 years) with a history of injecting illicit drugs and a diagnosis of an upper extremity soft tissue abscess. In the 694 patients with positive cultures the most common organism was Staphylococcus aureus, identified in 359 of 694 patients (52%). An increase in the incidence of oxacillin-resistant S. aureus over time was observed. Oxacillin-resistant S. aureus comprised 5% of S. aureus infections in 1999, 50% in 2001, 56% in 2003, and 82% in 2005. Microaerophilic streptococci were present in 37% of culture-positive cases and other anaerobes in 10%. Infections were monomicrobial in 366 of 694 patients (53%) and polymicrobial in 328 of 694 patients (47%). S. aureus is the most common pathogen in soft tissue abscesses in injecting drug abusers with an increasing incidence of oxacillin-resistant S. aureus. In addition to surgical decompression of abscesses, broad-spectrum empiric antibiotic therapy is necessary.