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INTRODUCTION: The authors sought to evaluate cost differences between shoulder arthroplasties and lower-extremity joint replacements in the outpatient and inpatient setting within a large health-maintenance organization. METHODS: A cross-sectional study of 100 total hip arthroplasties (THA), 100 total knee arthroplasties (TKA), and 100 shoulder arthroplasties (50 anatomical total shoulder arthroplasties and 50 reverse shoulder arthroplasties [RTSA]) was performed at a single regional health care center within an integrated health care maintenance organization. A time-driven activity-based costing methodology was used to obtain total cost of each episode for outpatient (vs) inpatient surgery. Results are presented by procedure type. RESULTS: Compared to their respective inpatient procedure, outpatient surgery was less expensive by 20% for RTSA, 22% for total shoulder arthroplasties, 29% for THA, and 30% for TKA. The cost of implants was the highest proportion of cost for all joint procedures across inpatient and outpatient settings, ranging from 28% of the total cost for inpatient THA to 63% of the cost for outpatient RTSA. DISCUSSION: Although many factors influence the total cost for arthroplasty surgery, including rate of hospitalization, duration of stay, operative time, complexity of cases, patient factors, equipment, and resource utilization, the implant cost remains the most expensive factor, with hospital bed admission status being the second costliest contribution. CONCLUSION: Outpatient total arthroplasty substantially reduced procedure expenses in a managed-care setting by 20%–30%, although savings for outpatient shoulder arthroplasty was lower than savings for THA or TKA. Implant costs remain the largest portion of shoulder arthroplasty procedure expenses.

Background All aspects of the arthroplasty pathway must be scrutinized to maximize value and eliminate unnecessary cost. Radiology providers’ contracts with hospitals often call for readings of all radiographs. This policy has little effect on patient care when intraoperative radiographs are taken and used to make real-time decisions. In order to determine the value of radiologist overreads, we asked 3 questions: what was the delay between the time an intraoperative radiograph was taken and time the report was generated, were the overreads accurate, and what is the associated cost? Methods Two hundred hip and knee radiograph reports generated over 6 months during 391 cases were reviewed. The time the report was dictated was compared to the time taken and time of surgery completion. To determine accuracy, each overread was rated as accurate or inaccurate. The cost of the overread was determined by multiplying the number of radiographs times the radiology fee less the technical fee. Results Median delay between taking the radiograph and filing the report was 45 minutes (range, 0-9778 minutes). Only 31.5% were filed before completion of the procedure. And 18.0% (36/200) were considered inaccurate despite lenient criteria. The reading fee for hip radiographs was $52.00, and for knee radiographs was $38.00, representing a total cost of $10,182 in our select series. This cost projects to $43,614 annually at our facility. Conclusion Radiology overreads of intraoperative radiographs have no effect on real-time decision-making. In the era of value-based care, payors should stop paying for overreads and reimburse providers who actually read the films intraoperatively.

AimsDebridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.MethodsA retrospective case series of 35 PJI TKA patients, with a median age of 67 years (interquartile range (IQR) 61 to 75), who underwent DAIR combined with IO vancomycin (500 mg), was performed with minimum 12 months' follow-up. A total of 26 patients with primary implants were treated for acute perioperative or acute haematogenous infections. Additionally, nine patients were treated for chronic infections with components that were considered unresectable. Primary outcome was defined by no reoperations for infection, nor clinical signs or symptoms of PJI.ResultsMean follow-up for acute infection was 16.5 months (12.1 to 24.2) and 15.8 months (12 to 24.8) for chronic infections with unresectable components. Overall non-recurrence rates for acute infection was 92.3% (24/26) but only 44.4% (4/9) for chronic infections with unresectable components. The majority of patients remained on suppressive oral antibiotics. Musculoskeletal Infection Society (MSIS) host grade was a significant indicator of failure (p < 0.001).ConclusionThe addition of IO vancomycin at the time of DAIR was shown to be safe with improved results compared to current literature using standard DAIR without IO antibiotic administration. Use of this technique in chronic infections should be applied with caution. While these results are encouraging, this technique requires longer follow-up before widespread adoption. Cite this article: Bone Joint J 2021;103-B(6 Supple A):185–190.

Background Medial unicompartmental knee arthroplasty (mUKA) is an increasingly popular treatment option for medial compartment knee osteoarthritis. Published mUKA survival rates have varied. The purpose of this meta-analysis was to provide pooled estimates of mUKA survival 5 and 10 years postoperatively. Methods We included studies in English within the last 15 years with a clear description of mUKA failure. Random-effects models were used to pool complementary log-log transformed implant survival estimates at 5 and 10 years postoperatively. Between-study variance was estimated using the restricted maximum likelihood method. Between-study heterogeneity was tested using the χ2 test and quantified using the I2 statistic. I2 values 75% were considered low, moderate, and high, respectively. Multivariable meta-regression was used to assess the potential association of mean patient age and study start year with survival estimates at 5 and 10 years. All analyses were performed using the metafor and meta packages implemented in R software version 3.3.4 (R Foundation for Statistical Computing, Vienna, Austria). Results Twenty-six studies met inclusion criteria, representing 42,791 knees. Study-level and pooled 5- and 10-year mUKA survival estimates were 95.3% (95% confidence interval, 93.6-96.6) and 91.3% (88.9-93.3), respectively. Between-study heterogeneity was high (>88%) for all years. Mean patient age and study start year explained only 12.3% and 30.7% of between-study heterogeneity at 5 and 10 years, respectively. Conclusion Five- and 10-year pooled mUKA survival estimates were 95.3% and 91.3%, respectively. These data establish better estimates of mUKA survivorship and can help when counseling patients considering mUKA.

Background The response to COVID-19 catalyzed the adoption and integration of digital health tools into the health care delivery model for musculoskeletal patients. The change, suspension, or relaxation of Medicare and federal guidelines enabled the rapid implementation of these technologies. The expansion of payment models for virtual care facilitated its rapid adoption. The authors aim to provide several examples of digital health solutions utilized to manage orthopedic patients during the pandemic and discuss what features of these technologies are likely to continue to provide value to patients and clinicians following its resolution. Conclusion The widespread adoption of new technologies enabling providers to care for patients remotely has the potential to permanently change the expectations of all stakeholders about the way care is provided in orthopedics. The new era of Digital Orthopaedics will see a gradual and nondisruptive integration of technologies that support the patient’s journey through the successful management of their musculoskeletal disease.

Background Routinely obtaining adjacent joint radiographs when evaluating patients with ankle fractures may be of limited clinical utility and an unnecessary burden, particularly in the absence of clinical suspicion for concomitant injuries. Methods One thousand, three hundred and seventy patients who sustained ankle fractures over a 5-year period presenting to two level 1 trauma centers were identified. Medical records were retrospectively reviewed for demographics, physical examination findings, and radiographic information. Analyses included descriptive statistics along with sensitivity and predictive value calculations for the presence of adjacent joint fracture. Results Adjacent joint imaging ( n =1045 radiographs) of either the knee or foot was obtained in 873 patients (63.7%). Of those, 75/761 patients (9.9%) demonstrated additional fractures proximal to the ankle joint, most commonly of the proximal fibula. Twenty-two of 284 (7.7%) demonstrated additional fractures distal to the ankle joint, most commonly of the metatarsals. Tenderness to palpation demonstrated sensitivities of 0.92 and 0.77 and positive predictive values of 0.94 and 0.89 for the presence of proximal and distal fractures, respectively. Additionally, 19/22 (86.4%) of patients sustaining foot fractures had their injury detectable on initial ankle X-rays. Overall, only 5.5% (75/1370) of patients sustained fractures proximal to the ankle and only 0.2% (3/1370) of patients had additional foot fractures not evident on initial ankle X-rays. Conclusion The addition of adjacent joint imaging for the evaluation of patients sustaining ankle fractures is low yield. As such, patient history, physical examination, and clinical suspicion should direct the need for additional X-rays. Level of evidence Level IV.

Background Incisional hernias are a complication in 10% of all open abdominal operations and can result in substantial morbidity. The purpose of this study was to determine whether inhibiting abdominal muscle contraction influences incisional hernia formation during the fascial healing after laparotomy. We hypothesized that decreasing the deformation of the abdominal musculature would decrease the size or occurrence of an incisional hernia. Methods Using an established rat model for incisional hernia, a laparotomy through the linea alba was closed with 1 mid-incision, fast-absorbing suture. Three groups were compared: a sham group (sham; n = 6) received no laparotomy, and the saline hernia (SH; n = 6) and Botox hernia (BH; n = 6) groups were treated once with equal volumes of saline or botulinum toxin (Botox, Allergan) before the incomplete laparotomy closure. On postoperative day 14, the abdominal wall was examined for herniation and adhesions, and contractile forces were measured for abdominal wall muscles. Results No hernias developed in the sham rats. Rostral hernias developed in all SH and BH rats. Caudal hernias developed in all SH rats, but in only 50% of the BH rats. Rostral hernias in the BH group were 35% shorter and 43% narrower compared with those in the SH group (P Conclusion In our rat model, partial paralysis of abdominal muscles decreases the number and size of incisional hernias. These results suggest that contractions of the abdominal wall muscle play a role in the pathophysiology of the formation of incisional hernias.

Carpal tunnel syndrome is frequently associated with traumatic injuries. The most common mechanisms include distal radius fractures and carpal/metacarpal fractures and dislocations. Less common etiologies include soft tissue blunt trauma, tendon ruptures, burns, thermal injuries, and insect bites. The index of suspicion for acute carpal tunnel syndrome should be high in patients with high-energy fractures and dislocations. In suspected cases of acute carpal tunnel syndrome, treatment should not be delayed and consists of surgical carpal tunnel release. Carpal tunnel syndrome can also present in delayed fashion several months after injury. In these cases, it can be treated like idiopathic carpal tunnel syndrome with conservative measures and/or surgery.

Purpose To evaluate the intra- and interobserver reliability of a scoring system for distal radius fracture union based on specific radiographic parameters obtainable from x-rays. Methods Two sets of 35 anteroposterior and lateral x-rays were obtained by retrospective review of consecutive patients with distal radius fractures (AO types A and C) treated by a single surgeon in 2009. One set was assembled for those patients treated nonsurgically and 1 set for those treated with open reduction and internal fixation (ORIF) with volar plating. Radius union scoring system (RUSS) scores were compiled from a 5-person review panel consisting of hand surgeons and musculoskeletal radiologists. Union of each of the 4 cortices was graded on a 3-point scale (0, fracture line visible with no callus; 1, callus formation but fracture line present; 2, cortical bridging without clear fracture line). Reviewers also recorded their overall impression of fracture union (united or not united). Each set of radiographs was reviewed twice by the 5 reviewers, 2 weeks apart. Inter- and intraobserver reliability were determined using intraclass correlation coefficients. Results For nonsurgically treated fractures, substantial agreement in union scores was found with regard to both intra- and interobserver reliability. For fractures treated with ORIF, substantial agreement was found in union scores with regard to intraobserver reliability and moderate agreement with regard to interobserver reliability. In addition, when using the reviewers' overall assessment of union as a reference standard, RUSS had a statistically significant predictive value in being able to differentiate between united and not united fractures. Conclusions This radiographic union tool demonstrated substantial intra- and interobserver reliability for the determination of fracture union in the distal radius. The RUSS is a simple method for a standardized assessment of radiographic union of DRF treated nonsurgically or with ORIF. Type of study/level of evidence Economic/decision analysis IV.

Adjacent segment disease (ASD) is disappointing long-term outcome for both the patient and clinician. In contrast to adjacent segment degeneration, which is a common radiographic finding, ASD is less common. The incidence of ASD in both the cervical and lumbar spine is between 2% and 4% per year, and ASD is a significant contributor to reoperation rates after spinal arthrodesis. The etiology of ASD is multifactorial, stemming from existing spondylosis at adjacent levels, predisposed risk to degenerative changes, and altered biomechanical forces near a previous fusion site. Numerous studies have sought to identify both patient and surgical risk factors for ASD, but a consistent, sole predictor has yet to be found. Spinal arthroplasty techniques seek to preserve physiological biomechanics, thereby minimizing the risk of ASD, and long-term clinical outcome studies will help quantify its efficacy. Treatment strategies for ASD are initially nonoperative, provided a progressive neurological deficit is not present. The spine surgeon is afforded many surgical strategies once operative treatment is elected. The goal of this manuscript is to consider the etiologies of ASD, review its manifestations, and offer an approach to treatment.

This article was updated on May 13, 2014. The third bullet point, which had previously read “Patients who have or are at risk of sustaining a distal radial fracture generally are elderly, are female, and have lower bone mineral densities and lower serum vitamin-D levels” was redundant with the second bullet point. The third bullet point now reads as follows: “Patients with a distal radial fracture are at an increased risk for future falls, which can lead to further morbidity and mortality.” As a consequence of our aging population, the public health burden of osteoporosis has reached epidemic proportions1. In 2004, 10 million persons in the United States carried the diagnosis of osteoporosis, and the prevalence of osteopenia reached 34 million2. Every third postmenopausal woman and every fifth man older than fifty years is estimated to have osteoporosis3. The World Health Organization (WHO) defines osteoporosis as a bone mineral density more than 2.5 standard deviations below the young adult mean for a given population4. Patients with decreased bone mineral density have increased bone fragility and are at increased fracture risk, especially for distal radial fracture5. The incidence of osteoporotic fractures was greater than 2 million in 2005 …

Background: We hypothesized that vertebral bone mineral density as measured in Hounsfield units (HU) by computed tomography (CT) can correlate with values obtained by dual x-ray absorptiometry (DXA). Our study aimed to report such a correlation along with the normative HU values within a large, heterogeneous population. Methods: We identified 2,020 trauma patients with a CT scan encompassing any part of their thoracic or lumbar spine. Mean HU values within each vertebral body were reported with respect to vertebral level, sex, and age. Using linear regression analysis, our data were also compared to DXA results in patients having both CT and DXA scans. Results: Analyses of CT scans yielded 28,083 unique vertebrae (18,489 male and 9,594 female) for which HU values were obtained. There were significant correlations between lumbar vertebral body HU and both DXA bone mineral density estimates (R2 = 0.50) and T-scores (p

Recently, both living and deceased organ donation rates have hit a plateau, despite increases in need for viable organs. One approach to improve donation rate is public education and policy; thus, it is necessary to understand the information the public is receiving regarding organ donation. We hypothesized that primetime medical dramas portray organ donation and transplantation in a negative manner. We compiled data on all primetime medical drama episodes with transplant themes from November 2008 through June 2010 and assessed depictions of organ donors and transplant candidates. Positive and negative thematic elements surrounding the process and individuals involved were also identified. One hundred and fifty-five million and 145 million households watched episodes containing any negative message and any positive message, respectively. Episodes containing only negative messages had over twice the household viewership per episode compared to episodes containing only positive messages (8.4 million vs. 4.1 million, p = 0.01). Widespread exposure to these representations may reinforce public misconceptions of transplantation. The transplant community should consider the popularity of medical dramas as an opportunity to impact the perception of organ donation and transplantation for millions of Americans.

We sought to estimate the effect of smoking on the biliary complication rate following orthotopic liver transplantation. We retrospectively evaluated the records of liver transplant recipients at our center from July 1, 1999 to October 26, 2007. Using Cox proportional hazards models, we estimated the time to the earliest biliary complication (leak or stricture) based on smoking exposure, as active, former, or lifetime nonsmoker, adjusting for other clinical factors. Overall, 409 liver transplant recipients were evaluated. The overall biliary complication rate was 37.7% (n = 154). Biliary complications included 66 anastomotic leaks, 60 anastomotic strictures, and 28 nonanastomotic lesions. ERCP was the primary diagnostic modality (n = 112). 18.1% of liver transplant recipients were active smokers (n = 74) and 42.8% were former smokers (n = 175). Active smokers were at greatest risk for biliary complications on unadjusted analysis (P = 0.022). After multivariable adjustment, active smokers had a 92% higher rate of biliary complication rates compared with lifetime nonsmokers (HR 1.92, 95% CI 1.07-3.43), but no difference was noted in the rate of complication resolution. Smoking clearly portends a significant risk of biliary complications following liver transplantation. Smoking status should be clearly defined when evaluating transplant candidacy and in counseling patients with cirrhosis.

Background Surgical operations at academic medical centers typically involve a resident physician performing cases together with, and/or under the supervision of, an attending physician. Although this is a widely accepted practice, recent emphasis on patient safety has led to scrutiny about this educational model. There are few studies evaluating whether complication rates, independent of patient risk factors, are affected by resident participation in operations. Study Design We identified 295 patients (590 breasts) who had undergone bilateral reduction mammoplasty led by a single attending surgeon between October 1, 1997 and September 30, 2008 at the University of Michigan Health System. In all cases, the attending operated on the right breast and the resident operated on the left breast under the supervision of the attending, allowing each patient to act as their own control. Their charts were retrospectively reviewed and major complications were defined as those requiring either an operation or hospitalization to treat. Results Twenty-three patients (7.8%) had a major complication after their breast reduction. Ten of these complications occurred in the left breast, 9 in the right breast, and 4 in both breasts. Statistical analysis revealed no differences in major complication rates between the side operated on with the primary surgeon being the resident versus the attending (4.7% versus 4.4%; p=1.00). Conclusions In the context of this single surgical operation, resident participation does not substantially affect major complication rates. The common residency training paradigm provides clinical experience and supervision without necessarily impacting patient safety. Analysis of additional operations in different settings will be necessary.

With the recent regulations limiting resident work hours, it has become more important to understand how residents spend their time. The volume and content of the pages they receive provide a valuable source of information that give insight into their workload and help identify inefficiencies in hospital communication. We hypothesized that above a certain workload threshold, paging data would suggest breakdowns in communication and implications for quality of care. All pages sent to six general surgery interns at the University of Michigan over the course of one academic year (7/1/2008-6/30/2009) were retrospectively categorized by sender type, message type, message modifier, and message quality. Census, discharge, and admission information for each intern service were also collected, and intern duties were further analyzed with respect to schedule. "On-call" days were defined as days on which the intern bore responsibility for care of all admitted floor patients. The interns received a total of 9,843 pages during the study period. During on-call shifts, each intern was paged an average of 57 ± 3 times, and those on non-call shifts received an average of 12 ± 3 pages. Floor/intensive care unit (ICU) nurses represented 32% of the page volume received by interns. Interestingly, as patient volume increased, there was a decrease in the number of pages received per patient. By contrast, at higher patient volumes, there was a trend toward an increasing percentage of urgent pages per patient. At high intern workloads, our data suggest no major communication breakdowns but reveal the potential for inferior quality of care.

Background Surgeons frequently struggle to determine patient suitability for liver transplantation. Objective and comprehensive measures of overall burden of disease, such as sarcopenia, could inform clinicians and help avoid futile transplantations. Study Design The cross-sectional area of the psoas muscle was measured on CT scans of 163 liver transplant recipients. After controlling for donor and recipient characteristics using Cox regression models, we described the relationship between psoas area and post-transplantation mortality. Results Psoas area correlated poorly with Model for End-Stage Liver Disease score and serum albumin. Cox regression revealed a strong association between psoas area and post-transplantation mortality (hazard ratio=3.7/1,000 mm 2 decrease in psoas area; p Conclusions Central sarcopenia strongly correlates with mortality after liver transplantation. Such objective measures of patient frailty, such as sarcopenia, can inform clinical decision making and, potentially, allocation policy. Additional work is needed develop valid and clinically relevant measures of sarcopenia and frailty in liver transplantation.

Arthroplasty implant fracture is a rare but critical complication that requires difficult revision surgery, often with poor results, patient disability, and significant cost. Several reports show component fracture either at the stem or at the neck interface after a relatively short postoperative course. We report such failure after 12 years, suggesting no safe period after which femoral implant fracture does not occur.

Purpose To determine interobserver reliability in measuring the cortical thickness of distal radiuses on posteroanterior radiographs obtained at the time of injury and to determine whether there is a correlation between distal radius cortical thickness and hip and lumbar spine scores on dual-energy x-ray absorptiometry (DXA). Methods Four orthopedic surgeons at 2 academic institutions who were blinded to the study protocol reviewed standard posteroanterior wrist radiographs of 80 women over age 50 years with distal radius fractures with DXA data obtained within the past 2 years. Radial bicortical widths were measured at 50 and 70 mm proximal to the distal ulnar articular surface, and mean bicortical thickness was calculated from radiographs of the injured wrist. Average bicortical width was compared with each patient's femoral and lumbar spine bone density measures. Data were analyzed using Pearson correlation coefficients and simple linear regression. Inter-rater reliability was evaluated using intra-class correlation coefficients. Results The inter-rater reliability for average bicortical thickness had a high intra-class correlation coefficient value of 0.91. Average bicortical thickness showed a statistically significant positive relationship with femoral bone density. Average bicortical thickness was statistically correlated with femoral bone density values, with a 1-mm increase in average bicortical thickness associated with a 0.05 g/cm 2 -increase in femoral density. Average bicortical thickness was not associated with lumbar bone density. Conclusions Bicortical thickness of the distal radius was positively correlated with femoral bone density but not with lumbar spine density. This may reflect similarity in quality and loading properties of the femur and radius as appendicular bones, compared with the axial spine. Identification of thinned distal radial cortices in association with distal radius fracture is a simple qualitative observation that should prompt further evaluation with DXA and medical management of bone insufficiency. Type of study/level of evidence Diagnostic II.

Background Unlike risk factors associated with sternotomy complications, those associated with sternal reconstruction have not been well elucidated. We sought to examine complication rates after sternal wound reconstruction and to identify perioperative risk factors associated with these complications. Methods We evaluated the records of 230 consecutive patients who underwent sternal reconstruction with muscle flaps after cardiac surgery. Patient demographics, clinical comorbidities, and operative procedure types were evaluated against two outcome variables—major complications and reconstructive failure. Results The mean age of our cohort was 62 y. Major complications (readmission, reoperation, or death) occurred in 76 patients (33%), including mortality rate of 3.5%. Obesity, chronic obstructive pulmonary disease, and type of reconstructive procedure correlated with an increased risk of major complications. Reconstructive failure occurred in 39 patients (17%) and was associated with female gender, obesity, previous coronary artery bypass graft procedure, and prior left internal mammary artery usage. Regression analyses demonstrated that obesity is independently associated with an increased risk of major complications and that women are at an increased risk of reconstructive failure. Reconstructions involving the rectus abdominis were correlated with an increased risk of major complications, but this difference was not significant in multiple regression analysis. Conclusions Usual risk factors for sternal wound development after cardiac surgery include diabetes, age, obesity, tobacco use, history of stroke, bilateral left internal mammary artery harvest, and significant blood transfusion. In distinction, this study found that the risks independently associated with major complications and reconstructive failures after reconstruction of sternal wounds are limited to obesity and female gender.

Objectives To determine whether risk for implantable cardioverter-defibrillator (ICD) therapy varies by body mass index (BMI) in systolic heart failure (HF). Background It is unknown whether obesity increases sudden death risk in patients with systolic HF. Methods Secondary analysis of patients with HF, left ventricular ejection fraction ≤0.40 and ICD (N = 464) was performed using Cox regression modeling to assess risk for first delivered ICD therapy, with patients grouped by BMI (kg/m2): normal (18.5 to

We sought to estimate the effect of smoking on the biliary complication rate following orthotopic liver transplantation. We retrospectively evaluated the records of liver transplant recipients at our center from July 1, 1999 to October 26, 2007. Using Cox proportional hazards models, we estimated the time to the earliest biliary complication (leak or stricture) based on smoking exposure, as active, former, or lifetime nonsmoker, adjusting for other clinical factors. Overall, 409 liver transplant recipients were evaluated. The overall biliary complication rate was 37.7% (n = 154). Biliary complications included 66 anastomotic leaks, 60 anastomotic strictures, and 28 nonanastomotic lesions. ERCP was the primary diagnostic modality (n = 112). 18.1% of liver transplant recipients were active smokers (n = 74) and 42.8% were former smokers (n = 175). Active smokers were at greatest risk for biliary complications on unadjusted analysis (P = 0.022). After multivariable adjustment, active smokers had a 92% higher rate of biliary complication rates compared with lifetime nonsmokers (HR 1.92, 95% CI 1.07-3.43), but no difference was noted in the rate of complication resolution. Smoking clearly portends a significant risk of biliary complications following liver transplantation. Smoking status should be clearly defined when evaluating transplant candidacy and in counseling patients with cirrhosis.

Every year in the US, over 40,000 individuals are killed and more than 3 million others injured as a result of motor vehicle collisions (MVCs). The economic cost of crash injuries each year is greater than $230 billion. In order to improve vehicle safety, a better understanding of the mechanism by which injuries are caused in current crashes as well as the human factors that affect injury tolerance is required. Biomechanical studies using cadavers suggest that factors such as bone density, muscle mass and body geometry influence the body’s ability to tolerate injurious forces. We hypothesized that fat in both the subcutaneous and visceral compartments may act as an energy absorbing material and affect injury patterns in MVCs. This study examined the relationship between the severity of the injuries sustained in MVCs and that occupant’s subcutaneous and visceral fat volumes as measured by CT. 139 adults MVC occupants were studied. Field and vehicle inspection was performed to determine crash configuration, crash severity and restraint use. All of the patients received CT evaluation of their abdomen and pelvis as part of their trauma workup. A three-dimensional image of the abdomen was reconstructed and volumetric measurement of both the subcutaneous and visceral fat were performed on a two-inch slab at the level of the third lumbar vertebra. The results showed that increased volume of either subcutaneous or visceral fat correlated with a significant decrease in the overall Injury Severity Score (ISS) (p