A Two-Stage Approach Integrating Provisional Biomaterial-Mediated Stabilization Followed by a Definitive Treatment for Managing Volumetric Muscle Loss Injuries.

Treatment of volumetric muscle loss (VML) faces challenges due to its unique pathobiology and lower priority in severe musculoskeletal injury management. Consequently, a need exists for multi-stage VML treatment strategies to accommodate delayed interventions owing to comorbidity management or prolonged casualty care in combat settings. To this end, polyvinyl alcohol (PVA) was used at concentrations of 5%, 7.5%, and 10% to generate provisional muscle void fillers (MVFs) of varying stiffness values (1.125 kPa, 3.700 kPa, and 7.699 kPa) to stabilize VML injuries as part of a two-stage approach. These were implanted into a rat model for a duration of 4 weeks, then explanted and either left untreated (control) or treated through minced muscle grafting (MMG). Additional benchmarks included acute MMG and unrepaired groups. At the MVF explant, the 7.5% PVA group exhibited superior neuromuscular function compared to the 5% and 10% PVA groups, the least fibrosis, and the largest median myofiber size among all groups at the 12-week endpoint. Despite the 7.5% PVA's superiority amongst the two-stage treatment groups, neuromuscular function was neither improved nor impaired relative to acute treatment benchmarks. This suggests that the future success of a two-stage VML treatment strategy will necessitate a more effective definitive intervention.

A Novel Use of a Schanz Pin-Rectal Foreign Body Extraction: A Case Report.

Introduction: Retained rectal foreign bodies (RFBs) can be difficult to extract, forcing the surgeon to get creative. This is the first case report utilizing orthopedic drilling and joystick manipulation techniques for foreign body extraction. Case Report: A 63-year-old male presented to the emergency department with a pool ball in his rectum for two days. Extraction attempts under anesthesia both transanally and through a low midline laparotomy were unsuccessful due to the patient's pelvic anatomy. Orthopedic surgery was consulted to see if any manipulation or resection of the pelvis might aid in extraction. Ultimately, a Schanz pin was drilled retrogradely from the rectum into the pool ball and successfully manipulated the pool ball out of the patient. Conclusion: Techniques such as drilling and joystick manipulation are common in orthopedic surgery but rarely used in other surgical fields. This case presented a novel use of a Schanz pin in RFB extraction. Application of orthopedic surgical technique in a colorectal surgery in this case saved the patient from more invasive interventions such as pubic symphysiotomy or ischial tuberosity resection.

External Fixation Before Planned Conversion to Internal Fixation in Orthopaedic Trauma: Controversies and Current Trends.

External fixation is a widely used technique for a myriad of bone fractures and pathologies in all extremities. Despite its widespread use, controversies and unknowns still exist. This review article seeks to discuss current literature surrounding pin insertion technique, pin-site care, intraoperative use during conversion to definitive fixation, the relationship of pin sites to definitive fixation, and pin-site management after removal for temporary external fixation.

Halicin remains active against Staphylococcus aureus in biofilms grown on orthopaedically relevant substrates.

Aims: Biofilm infections are among the most challenging complications in orthopaedics, as bacteria within the biofilms are protected from the host immune system and many antibiotics. Halicin exhibits broad-spectrum activity against many planktonic bacteria, and previous studies have demonstrated that halicin is also effective against Staphylococcus aureus biofilms grown on polystyrene or polypropylene substrates. However, the effectiveness of many antibiotics can be substantially altered depending on which orthopaedically relevant substrates the biofilms grow. This study, therefore, evaluated the activity of halicin against less mature and more mature S. aureus biofilms grown on titanium alloy, cobalt-chrome, ultra-high molecular weight polyethylene (UHMWPE), devitalized muscle, or devitalized bone. Methods: S. aureus-Xen36 biofilms were grown on the various substrates for 24 hours or seven days. Biofilms were incubated with various concentrations of halicin or vancomycin and then allowed to recover without antibiotics. Minimal biofilm eradication concentrations (MBECs) were defined by CFU counting and resazurin reduction assays, and were compared with the planktonic minimal inhibitory concentrations (MICs). Results: Halicin continued to exert significantly (p < 0.01) more antibacterial activity against biofilms grown on all tested orthopaedically relevant substrates than vancomycin, an antibiotic known to be affected by biofilm maturity. For example, halicin MBECs against both less mature and more mature biofilms were ten-fold to 40-fold higher than its MIC. In contrast, vancomycin MBECs against the less mature biofilms were 50-fold to 200-fold higher than its MIC, and 100-fold to 400-fold higher against the more mature biofilms. Conclusion: Halicin is a promising antibiotic that should be tested in animal models of orthopaedic infection.

Using AI to Write a Review Article Examining the Role of the Nervous System on Skeletal Homeostasis and Fracture Healing.

PURPOSE OF REVIEW: Three review articles have been written that discuss the roles of the central and peripheral nervous systems in fracture healing. While content among the articles is overlapping, there is a key difference between them: the use of artificial intelligence (AI). In one paper, the first draft was written solely by humans. In the second paper, the first draft was written solely by AI using ChatGPT 4.0 (AI-only or AIO). In the third paper, the first draft was written using ChatGPT 4.0 but the literature references were supplied from the human-written paper (AI-assisted or AIA). This project was done to evaluate the capacity of AI to conduct scientific writing. Importantly, all manuscripts were fact checked and extensively edited by all co-authors rendering the final manuscript drafts significantly different from the first drafts. RECENT FINDINGS: Unsurprisingly, the use of AI decreased the time spent to write a review. The two AI-written reviews took less time to write than the human-written paper; however, the changes and editing required in all three manuscripts were extensive. The human-written paper was edited the most. On the other hand, the AI-only paper was the most inaccurate with inappropriate reference usage and the AI-assisted paper had the greatest incidence of plagiarism. These findings show that each style of writing presents its own unique set of challenges and advantages. While AI can theoretically write scientific reviews, from these findings, the extent of editing done subsequently, the inaccuracy of the claims it makes, and the plagiarism by AI are all factors to be considered and a primary reason why it may be several years into the future before AI can present itself as a viable alternative for traditional scientific writing.

Role of the Neurologic System in Fracture Healing: An Extensive Review.

PURPOSE OF REVIEW: Despite advances in orthopedics, there remains a need for therapeutics to hasten fracture healing. However, little focus is given to the role the nervous system plays in regulating fracture healing. This paucity of information has led to an incomplete understanding of fracture healing and has limited the development of fracture therapies that integrate the importance of the nervous system. This review seeks to illuminate the integral roles that the nervous system plays in fracture healing. RECENT FINDINGS: Preclinical studies explored several methodologies for ablating peripheral nerves to demonstrate ablation-induced deficits in fracture healing. Conversely, activation of peripheral nerves via the use of dorsal root ganglion electrical stimulation enhanced fracture healing via calcitonin gene related peptide (CGRP). Investigations into TLR-4, TrkB agonists, and nerve growth factor (NGF) expression provide valuable insights into molecular pathways influencing bone mesenchymal stem cells and fracture repair. Finally, there is continued research into the connections between pain and fracture healing with findings suggesting that anti-NGF may be able to block pain without affecting healing. This review underscores the critical roles of the central nervous system (CNS), peripheral nervous system (PNS), and autonomic nervous system (ANS) in fracture healing, emphasizing their influence on bone cells, neuropeptide release, and endochondral ossification. The use of TBI models contributes to understanding neural regulation, though the complex influence of TBI on fracture healing requires further exploration. The review concludes by addressing the neural connection to fracture pain. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Cracking the Code: The Role of Peripheral Nervous System Signaling in Fracture Repair.

PURPOSE OF REVIEW: The traditionally understated role of neural regulation in fracture healing is gaining prominence, as recent findings underscore the peripheral nervous system's critical contribution to bone repair. Indeed, it is becoming more evident that the nervous system modulates every stage of fracture healing, from the onset of inflammation to repair and eventual remodeling. RECENT FINDINGS: Essential to this process are neurotrophins and neuropeptides, such as substance P, calcitonin gene-related peptide, and neuropeptide Y. These molecules fulfill key roles in promoting osteogenesis, influencing inflammation, and mediating pain. The sympathetic nervous system also plays an important role in the healing process: while local sympathectomies may improve fracture healing, systemic sympathetic denervation impairs fracture healing. Furthermore, chronic activation of the sympathetic nervous system, often triggered by stress, is a potential impediment to effective fracture healing, marking an important area for further investigation. The potential to manipulate aspects of the nervous system offers promising therapeutic possibilities for improving outcomes in fracture healing. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Do Not Lose Your Nerve, Be Callus: Insights Into Neural Regulation of Fracture Healing.

PURPOSE OF REVIEW: Fractures are a prominent form of traumatic injury and shall continue to be for the foreseeable future. While the inflammatory response and the cells of the bone marrow microenvironment play significant roles in fracture healing, the nervous system is also an important player in regulating bone healing. RECENT FINDINGS: Considerable evidence demonstrates a role for nervous system regulation of fracture healing in a setting of traumatic injury to the brain. Although many of the impacts of the nervous system on fracture healing are positive, pain mediated by the nervous system can have detrimental effects on mobilization and quality of life. Understanding the role the nervous system plays in fracture healing is vital to understanding fracture healing as a whole and improving quality of life post-injury. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Tranexamic Acid and Holding Venous Thromboembolism Prophylaxis Morning of Surgery Do Not Decrease Transfusion Requirements in Patients Undergoing Anterior Intrapelvic Approach for Acetabular Open Reduction and Internal Fixation.

INTRODUCTION: The objective of this study was to determine factors that may affect transfusion rates for patients requiring an anterior intrapelvic (AIP) approach for an acetabulum fracture. METHODS: This was a multicenter retrospective comparison study (3 trauma centers at two urban academic centers). Patients who had an AIP approach for an acetabulum fracture without other notable same-day procedures (irrigation and débridement and/or external fixation were only other allowed procedures) were included. One hundred ninety-five adult (18 and older) patients had adequate records to complete analysis with no preexisting coagulopathy. The main outcome evaluated was the number of units transfused at the time of surgery and up to 7 days after surgery. RESULTS: Factors that were found to affect intraoperative transfusion rates were older age, lower preoperative hematocrit, longer surgery duration, and requiring increased intraoperative intravenous fluids. Factors that did not affect transfusion rate included sex, body mass index, hip dislocation at the time of injury, fracture pattern, AIP approach alone or with lateral window ± distal extension, Injury Severity Score, preoperative platelet count, use of tranexamic acid, and venous thromboembolism prophylaxis received morning of surgery. When followed out through the remainder of a week after surgery, the results for any factor did not change. DISCUSSION: In this large multicenter retrospective study of patients requiring an AIP approach, tranexamic acid and use of venous thromboembolism prophylaxis (or holding it the morning of surgery) did not affect transfusion rates either during surgery or up to a week after surgery. Older age, lower preoperative hematocrit level, longer surgery time, and increased intraoperative intravenous fluids were associated with higher transfusion rates. DATA AVAILABILITY AND TRIAL REGISTRATION NUMBERS: Data are available on request. LEVEL OF EVIDENCE: Level 3, retrospective case-control study.

Skin Antisepsis before Surgical Fixation of Extremity Fractures.

BACKGROUND: Studies evaluating surgical-site infection have had conflicting results with respect to the use of alcohol solutions containing iodine povacrylex or chlorhexidine gluconate as skin antisepsis before surgery to repair a fractured limb (i.e., an extremity fracture). METHODS: In a cluster-randomized, crossover trial at 25 hospitals in the United States and Canada, we randomly assigned hospitals to use a solution of 0.7% iodine povacrylex in 74% isopropyl alcohol (iodine group) or 2% chlorhexidine gluconate in 70% isopropyl alcohol (chlorhexidine group) as preoperative antisepsis for surgical procedures to repair extremity fractures. Every 2 months, the hospitals alternated interventions. Separate populations of patients with either open or closed fractures were enrolled and included in the analysis. The primary outcome was surgical-site infection, which included superficial incisional infection within 30 days or deep incisional or organ-space infection within 90 days. The secondary outcome was unplanned reoperation for fracture-healing complications. RESULTS: A total of 6785 patients with a closed fracture and 1700 patients with an open fracture were included in the trial. In the closed-fracture population, surgical-site infection occurred in 77 patients (2.4%) in the iodine group and in 108 patients (3.3%) in the chlorhexidine group (odds ratio, 0.74; 95% confidence interval [CI], 0.55 to 1.00; P = 0.049). In the open-fracture population, surgical-site infection occurred in 54 patients (6.5%) in the iodine group and in 60 patients (7.3%) in the chlorhexidine group (odd ratio, 0.86; 95% CI, 0.58 to 1.27; P = 0.45). The frequencies of unplanned reoperation, 1-year outcomes, and serious adverse events were similar in the two groups. CONCLUSIONS: Among patients with closed extremity fractures, skin antisepsis with iodine povacrylex in alcohol resulted in fewer surgical-site infections than antisepsis with chlorhexidine gluconate in alcohol. In patients with open fractures, the results were similar in the two groups. (Funded by the Patient-Centered Outcomes Research Institute and the Canadian Institutes of Health Research; PREPARE ClinicalTrials.gov number, NCT03523962.).

Early Treatment of Acetabular Fractures Using an Anterior Approach Increases Blood Loss but not Packed Red Blood Cell Transfusion.

OBJECTIVE: The objective of this study was to determine whether time from hospital admission to surgery for acetabular fractures using an anterior intrapelvic (AIP) approach affected blood loss. DESIGN: Retrospective review. SETTING: Three level 1 trauma centers at 2 academic institutions. PATIENT SELECTION CRITERIA: Adult (18 years or older) patients with no pre-existing coagulopathy treated for an acetabular fracture via an AIP approach. Excluded were those with other significant same day procedures (irrigation and debridement and external fixation were the only other allowed procedures). OUTCOME MEASURES AND COMPARISONS: Multiple methods for evaluating blood loss were investigated, including estimated blood loss (EBL), calculated blood loss (CBL) by Gross and Hgb balance methods, and packed red blood cell (PRBC) transfusion requirement. Outcomes were evaluated based on time to surgery. RESULTS: 195 patients were studied. On continuous linear analysis, increasing time from admission to surgery was significantly associated with decreasing CBL at 24 hours (-1.45 mL per hour by Gross method, P = 0.003; -0.440 g of Hgb per hour by Hgb balance method, P = 0.003) and 3 days (-1.69 mL per hour by Gross method, P = 0.013; -0.497 g of Hgb per hour by Hgb balance method, P = 0.010) postoperative, but not EBL or PRBC transfusion. Using 48 hours from admission to surgery to define early versus delayed surgery, CBL was significantly greater in the early group compared to the delayed group (453 [IQR 277-733] mL early versus 364 [IQR 160-661] delayed by Gross method, P = 0.017; 165 [IQR 99-249] g of Hgb early versus 143 [IQR 55-238] g Hgb delayed by Hgb balance method, P = 0.035), but not EBL or PRBC transfusion. In addition, in multivariate linear regression, neither giving tranexamic acid nor administering prophylactic anticoagulation for venous thromboembolism on the morning of surgery affected blood loss at 24 hours or 3 days postoperative ( P > 0.05). CONCLUSION: There was higher blood loss with early surgery using an AIP approach, but early surgery did not affect PRBC transfusion and may not be clinically relevant. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Proteomic Analyses of Plasma From Patients With Fracture-Related Infection Reveals Systemic Activation of the Complement and Coagulation Cascades.

OBJECTIVES: The objective of this study was to compare plasma proteomes of patients with confirmed fracture-related infections (FRIs) matched to noninfected controls using liquid chromatography-mass spectrometry. DESIGN: This was a prospective case-control study. SETTING: The study was conducted at a single, academic, Level 1 trauma center. PATIENT SELECTION CRITERIA: Patients meeting confirmatory FRI criteria were matched to controls without infection based on fracture region, age, and time after surgery from June 2019 to January 2022. Tandem mass tag liquid chromatography-mass spectrometry analysis of patient plasma samples was performed. OUTCOME MEASURES AND COMPARISONS: Protein abundance ratios in plasma for patients with FRI compared with those for matched controls without infection were calculated. RESULTS: Twenty-seven patients meeting confirmatory FRI criteria were matched to 27 controls. Abundance ratios for more than 1000 proteins were measured in the 54 plasma samples. Seventy-three proteins were found to be increased or decreased in patients with FRI compared with those in matched controls (unadjusted t test P < 0.05). Thirty-two of these proteins were found in all 54 patient samples and underwent subsequent principal component analysis to reduce the dimensionality of the large proteomics dataset. A 3-component principal component analysis accounted for 45.7% of the variation in the dataset and had 88.9% specificity for the diagnosis of FRI. STRING protein-protein interaction network analysis of these 3 PCs revealed activation of the complement and coagulation cascades through the Reactome pathway database (false discovery rates <0.05). CONCLUSIONS: Proteomic analyses of plasma from patients with FRI demonstrate systemic activation of the complement and coagulation cascades. Further investigation along these lines may help to better understand the systemic response to FRI and improve diagnostic strategies using proteomics. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Humerus Nonunion Surgery in Patients With Initial Operative Fracture Fixation.

OBJECTIVES: To describe outcomes following humerus aseptic nonunion surgery in patients whose initial fracture was treated operatively and to identify risk factors for nonunion surgery failure in the same population. DESIGN: Retrospective case series. SETTING: Eight, academic, level 1 trauma centers. PATIENTS SELECTION CRITERIA: Patients with aseptic humerus nonunion (OTA/AO 11 and 12) after the initial operative management between 1998 and 2019. OUTCOME MEASURES AND COMPARISONS: Success rate of nonunion surgery. RESULTS: Ninety patients were included (56% female; median age 50 years; mean follow-up 21.2 months). Of 90 aseptic humerus nonunions, 71 (78.9%) united following nonunion surgery. Thirty patients (33.3%) experienced 1 or more postoperative complications, including infection, failure of fixation, and readmission. Multivariate analysis found that not performing revision internal fixation during nonunion surgery (n = 8; P = 0.002) and postoperative de novo infection (n = 9; P = 0.005) were associated with an increased risk of recalcitrant nonunion. Patient smoking status and the use of bone graft were not associated with differences in the nonunion repair success rate. CONCLUSIONS: This series of previously operated aseptic humerus nonunions found that more than 1 in 5 patients failed nonunion repair. De novo postoperative infection and failure to perform revision internal fixation during nonunion surgery were associated with recalcitrant nonunion. Smoking and use of bone graft did not influence the success rate of nonunion surgery. These findings can be used to give patients a realistic expectation of results and complications following humerus nonunion surgery. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Plating Versus Intramedullary Nailing of OTA/AO 43C1 and C2 Intra-articular Distal Tibia Fractures: A Propensity Score and Multivariate Analysis.

OBJECTIVE: To compare rates of reduction loss, nonunion, and infection in intra-articular distal tibia fractures (IADTF) treated with limited open reduction internal fixation and intramedullary nailing (IMN) as compared to open reduction internal fixation with plate and screws (plate fixation [PF]). DESIGN: Retrospective review. SETTING: Level-I academic trauma center. PATIENT SELECTION CRITERIA: Patients age ≥ 18 with OTA/AO 43C1 and C2 IADTF treated with IMN or PF between 2013-2021. OUTCOME MEASURES AND COMPARISONS: Loss of reduction, surgical site infection (SSI), nonunion, and patient-reported outcomes (PROs) were compared for IMN versus PF treatments. RESULTS: One hundred ten patients met the inclusion criteria (IMN 33 and PF 77). There was no loss of reduction found. Seventeen nonunions (15% overall; IMN 4/33 and PF 13/77) and 13 SSIs (12% overall; IMN 2/33 and PF11/77) were identified. Despite several risk factors being identified for nonunion and SSI in bivariate analysis, only open fracture remained significant as a risk factor for both nonunion (odds ratio 0.09 for closed fracture, 95% confidence interval, 0.02-0.56, P = 0.009) and SSI (odds ratio 0.07 for closed fracture, 95% confidence interval, 0.06-0.26, P = 0.012) in the multivariate model. Propensity scoring based on presurgical variables was significantly different between patients who received IMN versus PF ( P = 0.03); however, logistic regression incorporating the propensity score revealed no significant association with nonunion and SSI. Adjusting for the propensity score, there remained no association comparing IMN versus PF with nonunion and SSI ( P = 0.54 and P = 0.17, respectively). There was also no difference in PROs between IMN and PF (physical function: P = 0.25 and pain interference: P = 0.21). CONCLUSIONS: Overall nonunion and SSI prevalence was 15% and 12%, respectively, in operatively treated OTA/AO 43C1 and C2 IADTF. An open fracture was a significant risk factor for nonunion and SSI. Metaphyseal fixation through IMN or PF did not affect loss of reduction, nonunion, SSI, or PROs. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Work Productivity Loss After Minimally Displaced Complete Lateral Compression Pelvis Fractures.

OBJECTIVE: To quantify work impairment and economic losses due to lost employment, lost work time (absenteeism), and lost productivity while working (presenteeism) after a lateral compression pelvic ring fracture. Secondarily, productivity loss of patients treated with surgical fixation versus nonoperative management was compared. DESIGN: Secondary analysis of a prospective, multicenter trial. SETTING: Two level I academic trauma centers. PATIENT SELECTION CRITERIA: Adult patients with a lateral compression pelvic fracture (OTA/AO 61-B1/B2) with a complete posterior pelvic ring fracture and less than 10 mm of initial displacement. Excluded were patients who were not working or non-ambulatory before their pelvis fracture or who had a concomitant spinal cord injury. OUTCOME MEASURES AND COMPARISONS: Work impairment, including hours lost to unemployment, absenteeism, and presenteeism, measured by Work Productivity and Activity Impairment assessments in the year after injury. Results after non-operative and operative treatment were compared. RESULTS: Of the 64 included patients, forty-seven percent (30/64) were treated with surgical fixation, and 53% (30/64) with nonoperative management. 63% returned to work within 1 year of injury. Workers lost an average of 67% of a 2080-hour average work year, corresponding with $56,276 in lost economic productivity. Of the 1395 total hours lost, 87% was due to unemployment, 3% to absenteeism, and 10% to presenteeism. Surgical fixation was associated with 27% fewer lost hours (1155 vs. 1583, P = 0.005) and prevented $17,266 in average lost economic productivity per patient compared with nonoperative management. CONCLUSIONS: Lateral compression pelvic fractures are associated with a substantial economic impact on patients and society. Surgical fixation reduces work impairment and the corresponding economic burden. LEVEL OF EVIDENCE: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Reproducible Cartilage Impact Model to Generate Post-Traumatic Osteoarthritis in the Rabbit.

Post-traumatic osteoarthritis (PTOA) is responsible for 12% of all osteoarthritis cases in the United States. PTOA can be initiated by a single traumatic event, such as a high-impact load acting on articular cartilage, or by joint instability, as occurs with anterior cruciate ligament rupture. There are no effective therapeutics to prevent PTOA currently. Developing a reliable animal model of PTOA is necessary to better understand the mechanisms by which cartilage damage proceeds and to investigate novel treatment strategies to alleviate or prevent the progression of PTOA. This protocol describes an open, drop tower-based rabbit femoral condyle impact model to induce cartilage damage. This model delivered peak loads of 579.1 ± 71.1 N, and peak stresses of 81.9 ± 10.1 MPa with a time-to-peak load of 2.4 ± 0.5 ms. Articular cartilage from impacted medial femoral condyles (MFCs) had higher rates of apoptotic cells (p = 0.0058) and possessed higher Osteoarthritis Research Society International (OARSI) scores of 3.38 ± 1.43 compared to the non-impacted contralateral MFCs (0.56 ± 0.42), and other cartilage surfaces of the impacted knee (p < 0.0001). No differences in OARSI scores were detected among the non-impacted articular surfaces (p > 0.05).

High Nonunion and Amputations Rates With Either Early Intramedullary Nail Removal or Retention for Tibial Shaft Fracture-Related Infections.

OBJECTIVES: To compare debridement, antibiotics, and implant retention (DAIR) and intramedullary nail (IMN) removal with subsequent strategy for fracture stabilization in the treatment of tibia fracture-related infections (FRIs) occurring within 90 days of initial IMN placement. DESIGN: Retrospective case-control. SETTING: Four academic, Level 1 trauma centers. PATIENTS: Sixty-six patients who subsequently received unplanned operative treatment for FRI diagnosed within 90 days of initial tibia IMN. INTERVENTION: DAIR versus IMN removal pathways. MAIN OUTCOME MEASUREMENTS: Fracture union. RESULTS: Twenty-eight patients (42.4%) were treated with DAIR and 38 (57.6%) via IMN removal with subsequent strategy for fracture stabilization. Mean follow-up was 16.3 months. At final follow-up, ultimate bone healing was achieved in 75.8% (47/62), whereas 24.2% (15/62) had persistent nonunion or amputation. No significant difference was observed in ultimate bone healing ( P = 0.216) comparing DAIR and IMN removal. Factors associated with persistent nonunion or amputation were time from injury to initial IMN ( P < 0.001), McPherson systemic host grade B ( P = 0.046), and increasing open-fracture grade, with Gustilo-Anderson IIIB/IIIC fractures being the worst ( P = 0.009). Fewer surgeries after initial FRI treatment were positively associated with ultimate bone healing ( P = 0.029). CONCLUSIONS: Treatment of FRI within 90 days of tibial IMN with DAIR or IMN removal with subsequent strategy for fracture stabilization results in a high rate, nearly 1 in 4, of persistent nonunion or amputation, with neither appearing superior for improving bone healing outcomes. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Minced muscle autografting improves bone healing but not muscle function in a porcine composite injury model.

Composite tissue injuries (CTIs) in extremities include segmental bone defects (SBDs) and volumetric muscle loss. The objective of this study was to determine if skeletal muscle autografting with minced muscle grafts (MMGs) could improve healing in an SBD and improve muscle function in a porcine CTI model that includes an SBD and adjacent volumetric muscle loss injury. Adult Yucatan Minipigs were stratified into three groups including specimens with an isolated SBD, an SBD with volumetric muscle loss (CTI), and an SBD with volumetric muscle loss treated with MMG (CTI + MMG). Bone healing was quantified with serial x-rays and postmortem computed tomography scanning. Muscle function was quantified with a custom in vivo force transducer. Muscle tissue content was determined by biochemical analyses and histology. Anterior cortex-modified Radiographic Union Score for Tibia fractures (mRUSTs) decreased from 2.7 to 1.9 (p = 0.003) in CTI versus SBD animals. MMG improved anterior mRUST scores to 2.5 in CTI + MMG specimens (p = 0.030 compared to CTI specimens) and overall mRUST scores increased from 9.4 in CTI specimens to 11.1 in CTI + MMG specimens (p = 0.049). Residual strength deficits at euthanasia were 42% in SBD (p < 0.001), 44% in CTI (p < 0.001), and 48% in CTI + MMG (p < 0.001) compared to preoperative values. There were no differences in strength deficits between the three groups. Biochemical and histologic analyses demonstrated scattered differences between the three groups compared to contralateral muscle. MMG improved bone healing. However, the primary cause of muscle dysfunction and biochemical changes was the presence of an SBD. Clinical significance: Early mitigation of SBDs may be necessary to prevent muscle damage and weakness in patients sustaining composite extremity trauma.

The impact of heterotopic ossification prophylaxis after surgical fixation of acetabular fractures: national treatment patterns and related outcomes.

BACKGROUND: Heterotopic ossification (HO) is a common complication after surgical fixation of acetabular fractures. Numerous strategies have been employed to prevent HO formation, but results are mixed and optimal treatment strategy remains controversial. The purpose of the study was to describe current national heterotopic ossification (HO) prophylaxis patterns among academic trauma centers, determine the association between prophylaxis type and radiographic HO, and identify if heterogeneity in treatment effects exist based on outcome risk strata. METHODS: We used data from a subset of participants enrolled in the Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities (PREPARE) trial. We included only patients with closed AO-type 62 acetabular fractures that were surgically treated via a posterior (Kocher-Langenbeck), combined anterior and posterior, or extensile exposure. PREPARE Clinical Trial Registration Number: NCT03523962 Patient population This cohort study was nested within the Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities (PREPARE) trial. The PREPARE trial is a multicenter cluster-randomized crossover trial evaluating the effectiveness of two alcohol-based pre-operative antiseptic skin solutions. All PREPARE trial clinical centers that enrolled at least one patient with a closed AO-type 62 acetabular fracture were invited to participate in the nested study. RESULTS: 277 patients from 20 level 1 and level 2 trauma centers in the U.S. and Canada were included in this study. 32 patients (12%) received indomethacin prophylaxis, 100 patients (36%) received XRT prophylaxis, and 145 patients (52%) received no prophylaxis. Administration of XRT was associated with a 68% reduction in the adjusted odds of overall HO (OR 0.32, 95% CI, 0.14 - 0.69, p = 0.005). The overall severe HO (Brooker classes III or IV) rate was 8% for the entire cohort; XRT reduced the rate of severe HO in high-risk patients only (p=0.03). CONCLUSION: HO prophylaxis patterns after surgical fixation of acetabular fractures have changed dramatically over the last two decades. Most centers included in this study did not administer HO prophylaxis. XRT was associated with a marked reduction in the rate of overall HO and the rate of severe HO in high-risk patients. Randomized trials are needed to fully elucidate the potential benefit of XRT. PREPARE Clinical Trial Registration Number: NCT03523962.

Clinical Assessments of Fracture Healing and Basic Science Correlates: Is There Room for Convergence?

PURPOSE OF REVIEW: The purpose of this review is to summarize the clinical and basic science methods used to assess fracture healing and propose a framework to improve the translational possibilities. RECENT FINDINGS: Mainstays of fracture healing assessment include clinical examination, various imaging modalities, and assessment of function. Pre-clinical studies have yielded insight into biomechanical progression as well as the genetic, molecular, and cellular processes of fracture healing. Efforts are emerging to identify early markers to predict impaired healing and possibly early intervention to alter these processes. Despite of the differences in clinical and preclinical research, opportunities exist to unify and improve the translational efforts between these arenas to develop and optimize our ability to assess and predict fracture healing, thereby improving the clinical care of these patients.