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In the now 110 years that have passed since Kienböck first published his seminal description of lunate osteonecrosis, improvements in imaging technology and surgical technique have provided a better understanding of Kienböck disease pathogenesis and treatment. However, the precise etiology, natural history, and optimal treatment remain controversial. Future studies examining the genetics behind the disease and large-scale prospective studies comparing treatment options represent the next step in improving our understanding of this rare and complex phenomenon.

Bicycle utilization continues to increase annually, and this trend was recently accelerated by the coronavirus disease of 2019 pandemic. There is limited epidemiologic data, however, regarding the prevalence and nature of bicycle-related injuries. Therefore, the purpose of this study is to characterize trends in bicycle-related injuries. The National Electronic Injury Surveillance System was queried for bicycle-related injuries from 2012 to 2021. Patient demographic and injury data were collected and analyzed to describe trends in incidence, patient demographics, and injury patterns associated with an emergency department encounter for a bicycle-related injury. There were an estimated 4,666,491 (95% confidence interval: 4,661,472-4,671,510) bicycle-related injuries from 2012 to 2021. The incidence of these injuries has significantly decreased over time (R = -0.983, R

Ligament repair with suture-tape augmentation has been used in the operative treatment of joint instability and may have advantages with respect to early motion and stability. The purpose of this investigation was to describe the clinical results of traumatic elbow instability treated with lateral ulnar collateral ligament repair with suture-tape augmentation.All cases of acute and chronic elbow instability treated surgically between 2018 and 2020 were included if they underwent ligament repair with suture-tape augmentation of the lateral ulnar collateral ligament as part of the procedure. Cases with6 months of follow-up were excluded. A manual chart review was performed to record patient demographics as well as injury and surgery characteristics. Radiographic outcomes, range of motion, and patient-reported outcome measures, including the visual analog pain scale and Disabilities of the Arm, Shoulder, and Hand, were recorded. Range of motion measurements were recorded at the end of the clinical follow-up, as were surgical complications.Eighteen cases were included with a mean follow-up of 20 months. Five (28%) cases involved a high-energy mechanism, and 11 (62%) cases involved terrible triad fracture dislocations. The mean Disabilities of the Arm, Shoulder, and Hand questionnaire and visual analog pain scale scores were 17 and 2, respectively. The mean flexion-extension arc was 124°, and 2 (11%) cases had100° flexion-extension arc. There were 2 (11%) postoperative complications, and both cases had postoperative instability requiring reoperation. We observed no cases of capitellar erosion from the suture-tape material.For complex elbow instability, ligament repair with suture-tape augmentation of the lateral ulnar collateral ligament results in acceptable functional outcomes and a reoperation rate comparable with other joint stabilization procedures.Therapeutic IV.

Seasonal media reports often describe the dangers of pumpkin carving, yet little data exists regarding the actual incidence of hand injuries resulting from pumpkin carving. The purpose of this study is to describe, quantify, and trend ED encounters associated with pumpkin-related knife injuries.The National Electronic Injury Surveillance System (NEISS) was queried for pumpkin-related knife injuries from 2012 to 2021. Patient demographic and injury data was collected and analyzed to describe trends in incidence, patient demographics, and injury patterns associated with an ED encounter for a pumpkin-related knife injury.There were an estimated 20,579 (95% CI: 17,738-23,420) pumpkin-related knife injuries from 2012 to 2021. The incidence of pumpkin-related knife injuries remained stable over time (RPumpkin-related knife injuries are a preventable cause of hand injury with predictably high-incidence in fall months. Additionally, our data suggests further precautions should be taken to prevent injury in pediatric patients. Understanding at-risk populations in addition to implementing public safety initiatives and education on safe pumpkin-carving techniques could prevent serious injuries in the future.

Introduction With the increasing incidence of total shoulder arthroplasty (TSA) being performed worldwide, there is a growing effort to reduce postoperative pain, the consumption of opioids (oral morphine equivalents [OMEs]), and subsequent in hospital length of stay. Although perioperative pain control regimens have been widely studied in patients undergoing TSA, patients continue to consume a significant quantity of opioids after surgery. In the era of an opioid epidemic, novel methods for the improvement of perioperative pain control is of utmost importance. The aim of this quality improvement initiative was to evaluate the effect of liposomal bupivacaine (LB) versus ropivacaine (RP) in interscalene peripheral nerve blockade (IPNB) in patients undergoing TSA. Methods This quality improvement initiative prospectively evaluated a consecutive group of patients undergoing TSA from June 2017 to September 2019. Patients were included if they underwent either an anatomic or reverse shoulder arthroplasty at a single institution by 1 of 2 fellowship trained surgeons. Patients were divided in to 2 temporal cohorts based on the US Food and Drug administration's approval of LB. Patients who received a RPIPNB were in the control group, while those who received a LBIPNB were in the treatment group. Outcome measures studied included average visual analog pain scores (VAS) at 24 and 48 hours in the hospital, OME's, and length of stay. Results A total of 114 patients underwent TSA and met the inclusion criteria to be included in the analysis: 58 received RPIPNB and 56 received LBIPNB. The cohorts did not demonstrate any statistically different attributes (eg, age, sex, dominance, smoking status, psychiatric disorders, diabetes, HTN, or ASA class). Difference in 24 hour and 48 hour VAS pain scores was significantly improved in the LBIPNB group as compared to the RPIPNB group (2.46 vs. 0.72, and 2.02 and −0.41, respectively P Conclusion Despite significantly improved pain scores at 24 hours and 48 hours, patients who received LBIPNB did not demonstrate a statistically significant improvement in LOS or quantity of OME's consumed. The discrepancy between subjective numeric pain scores and objective healthcare metrics is likely multifactorial, and brings to light the difficulty in determining the value of new pain regimens. In lieu of these findings, it is difficult to endorse or reject the use of LBIPNB in TSA. Without further studies demonstrating improved efficacy in reduction of opioid consumption and LOS, given the additional expense of the drug, its continued use remains uncertain. Level of Evidence Level III.

Background There remains a paucity of epidemiologic data from recent years on the incidence of shoulder arthroplasty. We aimed to examine the recent trends and predict future projections of hemiarthroplasty (HA), anatomic (aTSA), and reverse shoulder arthroplasty (RSA), as well as compare these predictions to those for total hip (THA) and knee arthroplasty (TKA). Methods The National Inpatient Sample was queried from 2011 to 2017 for HA, aTSA, and RSA, as well as TKA and THA. Linear and Poisson regression was performed to project annual procedural incidence and volume to the year 2025. Results Between 2011 and 2017, the number of primary shoulder arthroplasties increased by 103.7%. In particular, RSA increased by 191.3%, with 63,845 RSAs performed in 2017. All projection models demonstrated significant increases in shoulder arthroplasty volume and incidence from 2017 to 2025. By 2025, the linear model predicts that shoulder arthroplasty volume will increase by 67.2% to 174,810 procedures whereas the Poisson model predicts a 235.2% increase, to 350,558 procedures by 2025. These growth rate projections outpace those of THA and TKA. Conclusions The number of shoulder arthroplasties has been increasing in recent years, largely because of the exponential increases in RSA. The overall incidence is increasing at a greater rate than TKA or THA, with projections continuing to rise over the next decade. These data and projections can be used by policy makers and hospitals to drive initiatives aimed at meeting these projected future demands.

The biceps brachii myotendinous unit, particularly the long head of the biceps tendon and its labral attachment, is a common cause of shoulder and arm pain. Its complex anatomy and normal variations can present a challenge when interpreting MR images. The purpose of this manuscript is to review the proximal biceps anatomy, variants, pathology, and post-operative appearance as seen on MRI. Recent data regarding the accuracy of clinical examination and MRI will be summarized.

BACKGROUND As the utilization of reverse total shoulder arthroplasty (RSA) grows, it is increasingly important to examine the relationship between hospital volume and RSA outcomes. We hypothesized that hospitals that perform a higher volume of RSAs would have improved outcomes. We also performed stratum-specific likelihood ratio (SSLR) analysis with the aim of delineating concrete definitions of hospital volume for RSA. METHODS The Nationwide Readmissions Database was queried for patients who had undergone elective RSA from 2011 to 2015. Annual hospital volume and 90-day outcome data were collected, including readmission, revision, complications, hospital length of stay (LOS), supramedian cost, and discharge disposition. SSLR analysis was performed to determine hospital volume cutoffs associated with increased risks for adverse events. Cutoffs generated through SSLR analysis were confirmed via binomial logistic regression. RESULTS The proportion of patients receiving care at high-volume centers increased from 2011 to 2015. SSLR analysis produced hospital volume cutoffs for each outcome, with higher-volume centers showing improved outcomes. The volume cutoffs associated with the best rates of 90-day outcomes ranged from 54 to 70 RSAs/year, whereas cost and resource utilization cutoffs were higher, with the best outcomes in hospitals performing >100 RSAs/year. SSLR analysis of 90-day readmission produced 3 hospital volume categories (1 to 16, 17 to 69, and ≥70 RSAs/year), each significantly different from each other. These were similar to the strata for 90-day revision (1 to 16, 17 to 53, and ≥54 RSAs/year) and 90-day complications (1 to 9, 10 to 68, and ≥69 RSAs/year). SSLR analysis produced 6 hospital volume categories for cost of care over the median value (1 to 5, 6 to 25, 26 to 47, 48 to 71, 72 to 105, and ≥106 RSAs/year), 5 categories for an extended LOS (1 to 10, 11 to 25, 26 to 59, 60 to 105, and ≥106 RSAs/year), and 4 categories for non-home discharge (1 to 31, 32 to 71, 72 to 105, and ≥106 RSAs/year). CONCLUSIONS We have defined hospital surgical volumes that maximize outcomes after RSA, likely related to surgical experience, ancillary staff familiarity, and protocolized pathways. This information may be used in future policy decisions to consolidate complex procedures, such as RSA, at high-volume destinations, or to encourage lower-volume institutions to strategize an approach to function as a higher-volume center. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Introduction: Salvage procedures such as proximal row carpectomy, 4-corner fusion, total wrist arthroplasty, and total wrist arthrodesis are commonly used at the end stages of wrist arthritis. These operations have high complication rates, and significant controversy exists regarding the selection of procedure. Long-term oral glucocorticoid therapy has previously been identified as a risk factor for complications in multiple orthopedic procedures. The purpose of this study is to investigate the effect long-term oral preoperative corticosteroid use has on complications after different salvage operations for wrist arthritis. Methods: The National Surgical Quality Improvement Program database was queried to identify patients who underwent proximal row carpectomy, 4-corner fusion, total wrist arthroplasty, or total wrist fusion between 2005 and 2020. Patients were classified by steroid use. Univariate analysis and multivariate logistic regression were used to assess the risk of complications. Results: A total of 1298 patients were identified. Overall, steroid use was found to be independently associated with a higher complication rate. On multivariate analysis of patients who underwent 4-corner fusion, steroid use was found to be associated with higher complication rate and surgical site infection rate. Steroid use was not associated with increased complications in patients who underwent proximal row carpectomy, total wrist arthroplasty, or total wrist fusion when examined individually. Conclusion: Long-term oral corticosteroid therapy was associated with an increased risk of postoperative infections in patients who underwent 4-corner fusion, which was not found in other wrist salvage operations.

Advanced imaging is increasingly used by upper extremity surgeons in the diagnosis and evaluation of peripheral nerve pathology. Ultrasound and magnetic resonance neurography (MRN) have emerged as the most far-reaching modalities for peripheral nerve imaging and often provide complimentary information. Technology improvements allow better depiction of the peripheral nervous system, allowing for more accurate diagnoses and preoperative planning. The purpose of this review is to provide an overview of current modalities and expected advances in peripheral nerve imaging with a focus on practical applications in the clinical setting. Ultrasound is safe, inexpensive, and readily available, and allows dynamic imaging with high spatial resolution as well as immediate evaluation of the contralateral nerve for comparison. It is primarily limited by its dependency on skilled operators and soft tissue contrast. The spatial evaluation of the perineural environment, fascicular echostructure, and nerve diameter are features of particular use in the diagnosis and treatment of nerve tumors, compressive lesions, and nerve trauma. Sonoelastrography has shown promise as a useful adjunct to standard sonographic imaging. MRN refers to the optimization of magnetic resonance image sequences and technology for visualization and contrasting nerves from surrounding structures. MRN provides excellent soft tissue contrast, depicts the entire nerve in 3 dimensions, allows for early evaluation of downstream muscle injury, and functions without operator dependency limits. Images provide details of nerve anatomic relationships, congruency, size, fascicular pattern, local and intrinsic fluid status, and contrast enhancement patterns, making MRN particularly useful in the setting of trauma, tumor, compressive lesions, and evaluation of brachial plexus injuries. Advances in MR volume and cinematic rendering software, magnet and coil technology, nerve-specific contrast media, and diffusion-weighted and tensor imaging will likely continue to expand the clinical application and indications for MRN.

Background:. Existing data on the epidemiology of shoulder arthroplasty are limited to future projections of incidence. However, the prevalence of shoulder arthroplasty (the number of individuals with a shoulder arthroplasty alive at a certain time and its implications for the burden of revision procedures) remains undetermined for the United States. Hence, the purpose of this study was to estimate the prevalence of shoulder arthroplasty in the United States. Methods:. The National Inpatient Sample (NIS) was queried to count all patients who underwent total shoulder arthroplasty (TSA), including both anatomic and reverse TSA, and hemiarthroplasty between 1988 and 2017. The counting method was used to calculate the current prevalence of TSA and hemiarthroplasty using age and sex-specific population and mortality data from the U.S. Census Bureau. Results:. In 2017, an estimated 823,361 patients (95% confidence interval [CI], 809,267 to 837,129 patients) were living in the United States with a shoulder replacement. This represents a prevalence of 0.258%, increasing markedly from 1995 (0.031%) and 2005 (0.083%). Female patients had a higher prevalence at 0.294% than male patients at 0.221%. Over 2% of people who were ≥80 years of age in the United States were living with a shoulder replacement. Furthermore, approximately 60% of patients living with a shoulder replacement had undergone the operation between 2013 and 2017. The incidence of revision shoulder arthroplasty is increasing on an annual basis, with 10,290 revision procedures performed in 2017, costing the U.S. health-care system $205 million. Conclusions:. The prevalence of shoulder arthroplasty in the United States has markedly increased over time. This trend will likely continue given increasing life expectancies and exponentially increasing shoulder arthroplasty incidence rates. Most patients do not have long-term follow-up, and revision shoulder arthroplasty rates are increasing, a trend that is projected to continue. The data from our study highlight the enormous public health impact of shoulder replacement and shed light on a potentially increasing revision burden.

Background Recent studies suggest increased complications when surgery closely follows corticosteroid injection. The purpose of this study was to understand the occurrence of surgical site infection (SSI), wound complications, and reoperation rates after carpal tunnel release (CTR) when corticosteroid injections were given within 180 days preoperatively. Methods Data were collected from the Truven MarketScan database from 2009 to 2018. Cohorts were created based on preoperative timing of injection (Results Overall, 223 899 patients underwent CTR. Of these, 17 391 (7.76%) had a preoperative injection in the 180 days preceding surgery. Univariate analysis demonstrated a relationship between timing of injections and noninfectious wound complications ( P = .006) and rate of 1-year reoperation ( P = .045). Univariate analysis demonstrated a relationship between number of injections and 1-year reoperation ( P < .001). On multivariate analysis, those receiving injections within 30 days preoperatively had increased rates of SSI ( P = .034) and noninfectious wound complications ( P = .006) compared with those with no injection or at other time points. Patients with 2 ( P = .002) or 3 or more injections ( P < .001) in the 180-day preoperative period had increased odds of 1-year reoperation. Conclusion Our study suggests increased risk of SSI, wound complications, and 1-year reoperation when corticosteroid injections are administered in the 30-day preoperative period. In addition, multiple steroid injections may increase the risk of 1-year reoperation.

Purpose Carpal tunnel syndrome is a common condition, with well-defined diagnostic and treatment guidelines. Despite these guidelines, continued variation in care exists, with providers variably using diagnostic tests and nonsurgical treatment modalities prior to surgery. The purpose of this study was to evaluate the variation and cost associated with the diagnosis and nonsurgical treatment of patients prior to undergoing carpal tunnel release. Methods We queried the Truven MarketScan database to identify patients who underwent carpal tunnel release from 2010 to 2017. Patients were identified using common current procedural terminology codes and included if they were enrolled in the database for a minimum of 12 months prior to surgery to allow all preoperative data to be captured. All associated current procedural terminology codes during the 1-year preoperative period were refined to codes related to median neuropathy and categorized as office visits, diagnostic imaging (x-ray, ultrasound, and magnetic resonance imaging), electrodiagnostic testing, injections, occupational or physical therapy, durable medical equipment, and preoperative laboratory tests. Results In total, 378,381 patients were included in the study. A per-patient average cost of $858.74 was spent on preoperative workup and nonsurgical treatment. Electrodiagnostic testing represented 44.6% of the cost, and office visits represented 31.9%. Regarding nonsurgical treatment, 16.1% of the patients received an injection during the 1-year preoperative period, 26.8% received a medical brace, and 6.6% used physical therapy. When analyzed based on age group, the per-patient average cost for patients aged 70 years or older was significantly less than those younger than 70 years ($723.92 vs $878.76). Conclusions Despite robust clinical practice guidelines and high volumes, significant variation in presurgical care exists. These data are useful to begin to critically analyze the causes of variation in the diagnosis and treatment of carpal tunnel syndrome and move toward a more effective, efficient, and informed treatment strategy. Type of study/level of evidence Economic/decision analysis II.

» Optimal management of nonunions of the proximal pole of the scaphoid is controversial and dependent on many patient and pathophysiologic considerations. » If the proximal pole subchondral bone support is sufficient, options include open reduction and internal fixation, either alone or in combination with autologous nonvascularized or vascularized bone graft. » If the proximal pole is not salvageable, replacement with osteochondral autografts or osteochondral flaps is the only option for reconstruction of the native anatomy.

Peripheral nerve and brachial plexus injuries are life-altering events, given the extensive compromise in shoulder, arm, and hand function. When these injuries do not recover, or attempts at nerve reconstructions fail to restore various functions of the upper extremity, patients are often left quite limited in their daily lives. Tendon transfers have been established in the hand and wrist as very successful options for many patients with peripheral nerve injuries isolated to one specific nerve or motor distribution. In recent years, tendon transfers around the shoulder and elbow have shown tremendous promise in restoring function what was traditionally very hard to treat proximal peripheral nerve lesions or upper trunk brachial plexus injuries. There are many important considerations when deciding on the appropriate tendon transfer option for these patients. Keeping these considerations in mind, we will review various types of shoulder, elbow, and hand functional deficits and the various tendon transfer options to reconstruct each one.

Background: The COVID-19 pandemic has led to changes to in-office orthopedic care, with a rapid shift to telemedicine. Institutions’ lack of established infrastructure for these types of visits has posed challenges requiring attention to confidentiality, safety, and patient satisfaction. Purpose: The aim of this study was to analyze the feasibility of telemedicine in orthopedics during the pandemic and its effect on efficiency and patient satisfaction. Methods: Patients seen by the Emory University Department of Orthopaedics Sports Medicine and Upper Extremity Divisions via telemedicine from March 23 to April 24, 2020, were contacted by telephone. Each patient was asked to respond to questions on satisfaction, ease of use, and potential future use; satisfaction with telemedicine and previous clinical visits were measured using a modified 5-point Likert scale. Results: Of the 762 patients seen, 346 (45.4%) completed the telemedicine questionnaire. Satisfaction varied by visit type, with average scores of 4.88/5 for in-office clinic visits versus 4.61/5 for telemedicine visits. There was no significant difference among age groups for satisfaction ratings. Patients 65 years old or older reported significantly longer visit times and decreased ease of use with the telemedicine platform. Conclusion: Telemedicine in a large orthopedics department was successfully implemented without compromising patient satisfaction. The use of telemedicine allows many patients to be seen quickly and efficiently without diminishing their musculoskeletal clinical experience.

Aims The impact of tobacco use on readmission and medical and surgical complications has been documented in hip and knee arthroplasty. However, there remains little information about the effect of smoking on the outcome after total shoulder arthroplasty (TSA). We hypothesized that active smokers are at an increased risk of poor medical and surgial outcomes after TSA. Methods Data for patients who underwent arthroplasty of the shoulder in the USA between January 2011 and December 2015 were obtained from the National Readmission Database, and 90-day readmissions and complications were documented using validated coding methods. Multivariate regression analysis was performed to quantify the risk of smoking on the outcome after TSA, while controlling for patient demographics, comorbidities, and hospital-level confounding factors. Results A total of 196,325 non-smokers (93.1%) and 14,461 smokers (6.9%) underwent TSA during the five-year study period. Smokers had significantly increased rates of 30- and 90-day readmission (p = 0.025 and 0.001, respectively), revision within 90 days (p < 0.001), infection (p < 0.001), wound complications (p < 0.001), and instability of the prosthesis (p < 0.001). They were also at significantly greater risk of suffering from pneumonia (p < 0.001), sepsis (p = 0.001), and myocardial infarction (p < 0.001), postoperatively. Conclusion Smokers have an increased risk of readmission and medical and surgical complications after TSA. These risks are similar to those found for smokers after hip and knee arthroplasty. Many surgeons choose to avoid these elective procedures in patients who smoke. The increased risks should be considered when counselling patients who smoke before undertaking TSA. Cite this article: Bone Joint J 2020;102-B(11):1549–1554.

This cross-sectional study uses data from the US Consumer Product Safety Commission’s National Electronic Injury Surveillance System to assess trends in the prevalence of electric scooter injuries in the US from 2014 to 2019.

The incidence of total shoulder arthroplasty (TSA) in increasing. Evidence in primary hip and knee arthroplasty suggest that preoperative opioid use is a risk factor for postoperative complication. This relationship in TSA is unknown. The purpose of this study was to investigate this relationship.The Truven Marketscan claims database was used to identify patients who underwent primary, unilateral TSA. Preoperative opioid use status was then used to divide patients into cohorts based on the average daily oral morphine equivalents (OMEs) received in the 6-month preoperative period. This included the following cohorts: opioid naïve and1, 1-5, 5-10, and10 average daily OMEs. In total, 29,454 patients with 90-day postoperative follow-up were included. Of these, 21,580 patients and 8959 patients had 1- and 3-year follow-up, respectively. Patient information and complication data were collected. Univariate and multivariate logistic regression were then performed to assess the association of preoperative opioid use with postoperative outcomes. A subgroup analysis was performed to examine revision surgery at 1 and 3 years postoperatively.Forty-four percent of identified patients received preoperative opioids, but the preoperative opioid-naïve patient became more common over the study period. Multivariate analysis demonstrated that patients receiving10 average daily OMEs (compared with opioid naïve) had higher odds of opioid overdose (odds ratio [OR] 4.17, 95% confidence interval [CI] 1.57-11.08, P = .004), wound complication (OR 2.04, 95% CI 1.44-2.89, P.001), superficial surgical site infection (OR 2.33, 95% CI 1.63-3.34, P.001), prosthetic joint infection (OR 3.41, 95% CI 2.50-4.67, P.001), pneumonia (OR 1.95, 95% CI 1.39-2.75, P.001), and thromboembolic event (OR 1.42, 95% CI 1.18-1.72, P.001). The same group had higher health care utilization, including extended length of stay, nonhome discharge, readmission, and emergency department visits (P ≤ .001). Total perioperative adjusted costs were more than $7000 higher in the10-OME group when compared to preoperative opioid-naïve patients.Opioid use prior to TSA is common and is associated with increased complications, health care utilization, revision surgery, and costs. This risk is dose dependent, and efforts should be made at cessation prior to surgery.

Surgical treatment of wrist arthritis in the younger patient population remains a challenging issue, and various surgical options need to be carefully considered for each patient. Proximal row carpectomy and 4-corner arthrodesis have proven to be reliable options for reducing pain and restoring adequate function in most young high-demand patients if the lunate facet is spared. Selective neurectomy has proven to be a promising stand-alone or complementary procedure for the treatment of pain that is associated with wrist arthritis in patients of all ages, with spared motion and the opportunity to perform additional procedures if pain continues. Alternative procedures, including capitolunate arthrodesis, total wrist arthrodesis, radial styloidectomy, total wrist arthroplasty, and wrist hemiarthroplasty, have considerable strengths and weaknesses and need to be studied further in younger patients.

Medial elbow injuries in the throwing athlete are common and increasing in frequency. They occur due to repetitive supraphysiologic forces acting on the elbow during the overhead throw. Overuse and inadequate rest are salient risk factors for injury. Most athletes improve substantially with rest and nonoperative treatment, although some athletes may require surgical intervention to return to play. Because of advances in conservative and surgical treatments, outcomes after medial elbow injury have improved over time. Currently, most athletes are able to return to a high level of play after ulnar collateral ligament reconstruction and experience a low rate of complications.

Purpose Loss of active shoulder abduction after brachial plexus or isolated axillary nerve injury is associated with a severe functional deficit. The purpose of this 2-center study was to retrospectively evaluate restoration of shoulder abduction after transfer of a radial nerve branch to the axillary nerve for patients after brachial plexus or axillary nerve injury. Methods Patients who underwent transfer of a radial nerve branch to the anterior branch of the axillary nerve between 2004 and 2014 were reviewed. A total of 27 patients with an average follow-up of 22 months were included. Outcome measures included pre- and postoperative shoulder abduction and triceps strength and active and passive shoulder range of motion. Results Shoulder abduction strength increased after surgery in 89% of patients. Average preoperative shoulder abduction was 12° compared with 114° after surgery. Twenty-two of 27 patients (81.5%) achieved at least M3 strength, with 17 of 27 patients (62.9%) achieving M4 strength. No differences were observed when subgroup analysis was performed for isolated nerve transfer versus multiple nerve transfer, mechanism of injury, injury level, branch of radial nerve transferred, or time from injury to surgery. A negative correlation was found comparing increasing age and both shoulder abduction strength and active shoulder abduction. No patients lost triceps strength after surgery. There were 4 patients who achieved no significant gain in shoulder abduction or deltoid strength and were deemed failures. No postoperative complications occurred. Conclusions Transfer of a branch of the radial nerve to the anterior branch of the axillary nerve was successful in improving shoulder abduction strength and active shoulder motion in the majority of the patients with brachial plexus or isolated axillary nerve injury. Type of study/level of evidence Therapeutic IV.

This study investigated the sensitivity, specificity, and accuracy of physical examination compared with high resolution sonography for the detection of the palmaris longus tendon in 136 wrists. The incidence of tendon absence was 10% by sonography and 14% by physical examination. The sensitivity of the physical examination was 94% and the specificity 86% compared with sonography as the reference standard. Accurate identification of the palmaris longus tendon through physical examination was not influenced by body mass index or wrist circumference. Upon review of the sonography images, none of the palmaris longus tendons missed on physical examination were considered to be adequate for grafting based on expert opinion. While physical exam was 93% accurate for detection of the palmaris longus tendon compared with ultrasound, our study suggests that it is sufficient for detection of those tendons that can be used as donors clinically.

Recent media reports have described knife injuries sustained while preparing avocados; however, this rise has not been reported in the literature. The purpose of this study is to describe, quantify, and trend emergency department (ED) encounters associated with avocado-related knife injuries.The National Electronic Injury Surveillance System (NEISS) was queried for avocado-related knife injuries from 1998 to 2017. Patient demographic and injury data was collected and analyzed to describe trends in incidence, patient demographics, and injury patterns associated with an ED encounter for an avocado-related knife injury.There were an estimated 50,413 (95% Confidence Interval: 46,333-54,492) avocado-related knife injuries from 1998 to 2017. The incidence of avocado-related knife injuries increased over this time period (1998-2002 = 3143; 2013-2017 = 27,059). This increase correlated closely with a rise in avocado consumption in the U.S. (Pearson's Correlation: 0.934, p 0.001) Women comprised 80.1% of injuries. The most common demographic injured were 23 to 39-year old females (32.7%), while the least common was males under the age of 17 (0.9%). Most ED presentations occurred on Saturdays (15.9%) or Sundays (19.9%) and the majority occurred during the months of April through July (45.6%). Injuries were much more common on the left (and likely non-dominant) hand.Avocado-related knife injuries are a preventable cause of hand injury. The incidence has risen significantly in recent years, possibly due to an increased consumption of avocados in the United States. Education on safe avocado preparation techniques and public safety initiatives, such as warning labels, could help prevent serious injuries in the future.

Purpose Underinsured hand trauma patients are more likely to be transferred to quaternary care centers, which burdens these patients and centers. By increasing insurance coverage, care for less severe upper-extremity injuries may be available closer to patients’ homes. We evaluated whether the 2014 expansion of Medicaid in Maryland under the Affordable Care Act decreased the number of uninsured upper-extremity trauma patients and the volume of unnecessary emergency trauma visits at our hand center. Methods We identified all upper-extremity trauma patients between 2010 and 2017 at our hand trauma referral center. Injury severity was classified based on the need for subspecialty care. Bivariate relations between insurance status and demographic covariates, including injury type and distance, both before and after Medicaid expansion were evaluated. We used patient-level and multinomial logistic regression models to evaluate changes in payer and transfer appropriateness. Results We studied 12,009 acute upper-extremity trauma patients. With Medicaid expansion, the percentage of trauma patients with Medicaid coverage increased from 15% to 24%, with a decrease in uninsured from 31% to 24%. After Medicaid expansion, non-transfer patient appropriateness decreased and appropriateness of transfers remained consistent across all payers. The average distance patients traveled for care remained similar before and after expansion. Conclusions Medicaid expansion significantly decreased the proportion of uninsured upper-extremity trauma patients. We identified no significant changes in the distances these patients traveled for specialized care. In addition, the appropriateness of transferred patients did not change significantly after expansion, whereas appropriateness of nontransferred patients actually declined after Medicaid expansion. Clinical relevance This study indicates no notable change in adherence to transfer guidelines after expansion, and a possible increase in use of emergency services by newly insured patients.

Background: Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. Methods: A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. Results: There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). Conclusions: For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

Background: Small olecranon fractures present a significant challenge for fixation, which has resulted in development of plates with proximal extension. Olecranon-specific plates with proximal extensions are widely thought to offer superior fixation of small proximal fragments but have distinct disadvantages: larger dissection, increased hardware prominence, and the increased possibility of impingement. Previous biomechanical studies of olecranon fracture fixation have compared methods of fracture fixation, but to date there have been no studies defining olecranon plate fixation strength for standard versus extended olecranon plates. The purpose of this study is to evaluate the biomechanical utility of the extended plate for treatment of olecranon fractures. Methods: Sixteen matched pairs of fresh-frozen human cadaveric elbows were used. Of the 16, 8 matched pairs received a transverse osteotomy including 25% and 8 including 50% of the articular surface on the proximal fragment. One elbow from each pair was randomly assigned to a standard-length plate, and the other elbow in the pair received the extended-length plate, for fixation of the fracture. The ulnae were cyclically loaded and subsequently loaded to failure, with ultimate load, number of cycles, and gap formation recorded. Results: There was no statistically significant difference between the standard and extended fixation plates in simple transverse fractures at either 25% or 50% from the proximal most portion of the articular surface of the olecranon. Conclusion: Standard fixation plates are sufficient for the fixation of small transverse fractures, but caution should be utilized particularly with comminution and nontransverse fracture patterns.

Background: Ballistic fractures of the carpus and hand are routinely treated in large urban centers. These injuries can be challenging due to many factors. Various treatment options exist for these complicated injuries, but there are limited data available. This report analyzes patient demographics, treatments, and outcomes at a large urban trauma center. Methods: All ballistic fractures of the hand and wrist of the patients who presented to a single center from 2011 to 2014 were retrospectively reviewed. Patient demographics, injury mechanism, treatment modalities, and outcomes were analyzed. Results: Seventy-seven patients were identified; 70 were male, and 7 were female. Average age of the patients was 29.6 years. Seventy-five injuries were low velocity, whereas 2 were high velocity. Sixty-seven patients had fractures of a metacarpal or phalanx, whereas 4 had isolated carpal injuries. Six had combined carpal and metacarpal or phalanx fractures. Thirty-six patients had concomitant tendon, nerve, or vascular injuries requiring repair. Sixty-three patients underwent operative intervention, with the most common intervention being percutaneous fixation. Sixteen patients required secondary surgery. Eighteen complications were reported. Conclusions: The majority of patients in this report underwent early operative intervention with percutaneous fixation. Antibiotics were administered in almost all cases and can usually be discontinued within 24 hours after surgery. It is important to consider concomitant nerve, vascular, or tendon injuries requiring repair. We recommend early treatment of these injuries with debridement and stabilization. Due to lack of follow-up and patient noncompliance, early definitive treatment with primary bone grafting should be considered.

This article reports a series of severe permanent brachial plexus injuries in American football players. The authors describe the mechanisms of injury and outcomes from a more contemporary treatment approach in the form of nerve transfer tailored to the specific injuries sustained. Three cases of nerve transfer for brachial plexus injury in American football players are discussed in detail. Two of these patients regained functional use of the extremity, but 1 patient with a particularly severe injury did not regain significant function. Brachial plexus injuries are found along a spectrum of brachial plexus stretch or contusion that includes the injuries known as “stingers.” Early identification of these severe brachial plexus injuries allows for optimal outcomes with timely treatment. Diagnosis of the place of a given injury along this spectrum is difficult and requires a combination of imaging studies, nerve conduction studies, and close monitoring of physical examination findings over time. Although certain patients may be at higher risk for stingers, there is no evidence to suggest that this correlates with a higher risk of severe brachial plexus injury. Unfortunately, no equipment or strengthening program has been shown to provide a protective effect against these severe injuries. Patients with more severe injuries likely have less likelihood of functional recovery. In these patients, nerve transfer for brachial plexus injury offers the best possibility of meaningful recovery without significant morbidity. [ Orthopedics. 2016; 39(6):e1188–e1192.]

To examine health status and health care experiences of homeless patients in health centers and to compare them with their nonhomeless counterparts.Nationally representative data from the 2009 Health Center Patient Survey.Cross-sectional analyses were limited to adults (n = 2,683). We compared sociodemographic characteristics, health conditions, access to health care, and utilization of services among homeless and nonhomeless patients. We also examined the independent effect of homelessness on health care access and utilization, as well as factors that influenced homeless patients' health care experiences.Computer-assisted personal interviews were conducted with health center patients.Homeless patients had worse health status-lifetime burden of chronic conditions, mental health problems, and substance use problems-compared with housed respondents. In adjusted analyses, homeless patients had twice the odds as housed patients of having unmet medical care needs in the past year (OR = 1.98, 95 percent CI: 1.24-3.16) and twice the odds of having an ED visit in the past year (OR = 2.00, 95 percent CI: 1.37-2.92).There is an ongoing need to focus on the health issues that disproportionately affect homeless populations. Among health center patients, homelessness is an independent risk factor for unmet medical needs and ED use.

Objectives. We examined primary care and public health activities among federally funded health centers, to better understand their successes, the barriers encountered, and the lessons learned.Methods. We used qualitative and quantitative methods to collect data from 9 health centers, stratified by administrative division, urban–rural location, and race/ethnicity of patients served. Descriptive data on patient and institutional characteristics came from the Uniform Data System, which collects data from all health centers annually. We administered questionnaires and conducted phone interviews with key informants.Results. Health centers performed well on primary care coordination and community orientation scales and reported conducting many essential public health activities. We identified specific needs for integrating primary care and public health: (1) more funding for collaborations and for addressing the social determinants of health, (2) strong leadership to champion collaborations, (3) trust building...

The Bureau of Primary Health Care (BPHC), in the Health Resources and Services Administration (HRSA), funds over 1,100 health centers to provide primary and preventive care to about 19 million underserved patients throughout the nation (Health Resources and Services Administration). Under Section 330 of the Public Health Service Act, the federal Health Center Program has been serving vulnerable populations since 1965 and has been championed as a model delivery system for improving access to care and reducing disparities (Shi et al. 2001a,b; Shi et al. 2004, 2009; Proser 2005; Hadley, Cunningham, and Hargraves 2006; Shi, Stevens, and Politzer 2007). The year 2008 marked the beginning of a program-wide clinical quality improvement initiative to measure and demonstrate quality of care across all BPHC-funded health centers (Health Resources and Services Administration). As part of this initiative, the Health Center Program now incorporates an array of performance measures into its annual data reporting activities, emphasizing a combination of indicators measuring both processes of care and health outcomes. The performance measures tracked by HRSA are consistent with those endorsed by the National Quality Forum, AQA Alliance (formerly the Ambulatory Care Quality Alliance), and other national quality organizations; are designed to address priority health conditions of HRSA safety-net populations throughout the life cycle; and are amenable to quality improvement. For instance, quality measures include indicators of screening for cervical cancer, which disproportionately affects vulnerable populations served by HRSA-funded health centers and for which early detection and care can significantly decrease mortality and improve 5-year survival. Other measures include access to prenatal care, low birth weight, age-appropriate immunizations, and chronic disease management indicators for diabetes and hypertension. In years past, a number of studies have evaluated health centers' performance on quality-related indicators. This prior research found that health centers performed quite well with respect to prenatal care outcomes; specifically, rates of low birth weight in health centers were comparable or lower than other provider settings nationwide, despite the fact that health centers serve higher-risk groups (Politzer et al. 2001; Regan et al. 2003; Haq 2007). In addition, cervical cancer screening rates in health centers exceeded national rates, overall and for specific racial/ethnic and insurance groups (Regan, Lefkowitz, and Gaston 1999; Politzer et al. 2001; Regan et al. 2003; Shi and Stevens 2007; Dor et al. 2008; Shin et al. 2008; Shi et al. 2009). Health centers have also generally shown comparable performance in terms of childhood immunization rates (Schempf, Politzer, and Wulu 2003). However, past research found room for improvement in performance in the management of chronic diseases. Studies of health center patients conducted 10 years ago suggested that only about 50 percent of patients with hypertension, and 40–60 percent of patients with diabetes, received appropriate care (Chin et al. 2000; Hicks et al. 2006). Quality improvement efforts, such as the various Health Disparities Collaboratives implemented within health centers, showed progress in diabetes-related prevention, screening, treatment, and monitoring activities, as well as cancer screening, while the collaboratives were in operation; however, no improvements were demonstrated in hypertension (Chin et al. 2004, 2007; Chien, Walters, and Chin 2007; Landon et al. 2007). There was also mixed evidence regarding the impact of these interventions on longer-term patient outcomes, such as control of glycated hemoglobin levels for diabetes and control of blood pressure for hypertension (Chien, Walters, and Chin 2007; Landon et al. 2007). While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. While informative, these studies may not serve as the best preface to the current state of clinical quality in health centers. Prior data sources date back at least 5 years, preceding the current quality improvement initiative at HRSA, and previous analyses often included regional rather than national data, possibly limiting the generalizability of the findings. To address this gap in the health center literature, this study sought to provide the most recent national analyses of clinical quality performance across health centers, using 2009 Uniform Data System (UDS) data from HRSA. The purpose of this study was to provide a description of the current status of clinical quality among the nation's health centers, to compare the status with similar national measures, and to examine health center patient, provider, and institutional characteristics associated with performance excellence. We utilized 2009 data from the UDS, to which all health centers are required to submit a variety of aggregated information on an annual basis. Other studies have often included nonrandom and/or regional samples of health centers, but use of the UDS data enables the calculation of national estimates. Finally, previous studies tended to focus on processes of care as indicators of quality rather than both processes of care and health outcomes.

Recent reports suggest the need for further study of the impact of organizational char- acteristics on quality-related activities in health centers. To better understand these issues, a cross- sectional assessment of quality-related activities in Health Resources and Services Administration- funded health centers was conducted using a mailed questionnaire. Associations between the extent and frequency of quality-related activities and organizational characteristics, including lo- cation, size, and accreditation status, were examined. In general, the frequency and type of most quality-related activities did not vary greatly by size and location, but differed by accreditation sta- tus. The findings can be explained in part by Health Resources and Services Administration/Bureau of Primary Health Care requirements and implementation of their Accreditation Initiative.

Functional success after below-knee amputation (BKA) has been poorly studied. The purpose of this study was to establish a consistent definition of “successful outcome” after BKA and to identify clinical variables influencing that definition. Three hundred nine consecutive patients undergoing BKA were evaluated postoperatively using the following definition for “successful outcome”: 1) wound healing of the BKA without need for revision to a higher level; 2) maintenance of ambulation with a prosthesis for at least 1 year or until death; and 3) survival for at least 6 months. Independent clinical predictors influencing outcome were determined using bivariate and multivariable logistic regression analyses. For the cohort, median survival and maintenance of ambulation were 44 months and 60 months, respectively. Although 86.4 per cent of patients healed without the need for revision to a higher level, 63.4 per cent maintained ambulation with a prosthesis for 1 year and 86.1 per cent survived for 6 months, successful outcome as defined by attaining all three components of the definitions occurred in only 51.1 per cent (n = 158) of patients. Of 19 clinical variables examined, six were identified in bivariate analysis as significantly associated with outcome. However, only three were found to be independent predictors of outcome using logistic regression modeling. The presence of coronary artery disease [odds ratio (OR), 0.465; 95% CI, 0.289–0.747], cerebrovascular disease (OR, 0.389; 95% CI, 0.154–0.980), and impaired ambulatory ability before BKA (OR, 0.310; 95% CI, 0.154–0.623) were each associated with a decreased odds for successful outcome. Patients who presented with impaired ambulatory ability in combination with another independent predictor had only a 20 per cent to 23 per cent probability of successful outcome and patients who presented with all three had a 10.4 per cent probability of success. In contrast, patients who had none of the independent predictors at presentation had a 67.5 per cent probability of successful outcome after BKA. A standardized definition of success after BKA capable of predicting outcomes is feasible and can be a useful tool to determine rehabilitation potential. When judged by our definition, patients without predictors of failure possess a high potential for rehabilitation, whereas patients with multiple predictors rarely rehabilitate, should probably receive palliative above-knee amputation, and forgo the expense of futile prosthetic training.

Background Subscapularis dysfunction remains a significant problem after shoulder arthroplasty. Published techniques have variable recommendations for placing a rotator interval closing suture in attempts to off-load the subscapularis repair site, the implications of which have yet to be examined in the literature. The goals of this study were to investigate the biomechanical benefit of the rotator interval closing suture on the subscapularis repair strength and to analyze the effect on shoulder range of motion. Methods Sixteen matched cadaveric shoulders underwent a subscapularis tenotomy and shoulder arthroplasty. The subscapularis tenotomy was repaired, and motion at physiologic torsional force was recorded. One of each matched pair was randomly assigned to receive an additional rotator interval closure suture. Each specimen then underwent a standardized cyclic loading with measurement of gap formation and load to failure. Results The rotator interval closing suture significantly increased the ultimate load to failure of the subscapularis repair (452 N vs. 219 N; P = .002) and decreased gap formation at the subscapularis repair site. Measurement of the shoulder motion showed no significant difference between shoulders with and without the rotator interval closing suture. Discussion We report the additional biomechanical benefit that the rotator interval closing suture provides to the subscapularis repair site after shoulder arthroplasty. This suture acts to improve the load to failure of the subscapularis repair and to decrease gap formation under cyclic load. Furthermore, it does not detrimentally affect shoulder external rotation or overall arc of rotation. Our findings support the application of this off-loading technique after subscapularis repair during shoulder arthroplasty.

This paper presents a theoretical and numerical investigation of the spatially averaged electric field in the beam of a circular aperture. The investigation leads to closed-form analytical expressions, based on scalar diffraction theory, which describe the spatially averaged electric field in the Fresnel region of a circular aperture excited by a spatially uniform, harmonic plane wave. The expressions ultimately permit rapid, practical, and efficient prediction of certain routine electromagnetic measurements. Because the expressions are valid in the Fresnel region, they are also valid in the near field, the far field, and the Fraunhofer region of a circular aperture. In fact, it is shown that the closed-form expressions contain, as special cases, classic on-axis and far-field results associated with a circular aperture. The analytical expressions are based on a generalization of Fresnel diffraction originally developed by Lommel in the late 1800s. Hence, a thorough review of the literature on the Lommel diffraction formulation is presented. Finally, it is shown that results obtained from the closed-form expressions compare quite favorably to results obtained from the exact solution computed via the dyadic Green's function approach.

Objectives To determine the association between race on severe heterotopic ossification (HO) following acetabular fracture surgery. Design Retrospective case control study. Setting Level I university trauma centre. Methods Two hundred and fifty-three patients who were surgically treated for acetabular fractures were retrospectively evaluated. Postoperative radiographs were evaluated for HO by a blinded musculoskeletal radiologist, and classified based on a modified Brooker classification. Results Of the 253 patients that met inclusion and exclusion criteria, 175 (69%) were male and 78 (31%) were female. One hundred and fifty-four (61%) patients were Caucasian, and 99 (39%) were African American (AA). Fifty-five (21%) patients developed severe HO. Of those who developed severe HO, 25 were Caucasian (45%), 30 were African American (55%). Forty-one patients (75%) with severe HO were male, and 14 (25%) were female. No statistical differences (p > 0.05) were found between groups in terms of age, days to surgery, GCS at presentation, surgical approach, perioperative HO prophylaxis, or AO/OTA fracture classification. The patient population was then stratified by race, gender, and race/gender. AA were more likely than Caucasians to develop severe HO (odds ratio [OR], 2.24; confidence interval [CI], 1.22–4.11). When gender was considered independent of race, no statistical differences (p > 0.05) were observed (OR, 1.40; CI, 0.71–2.75). AA males were much more likely to develop severe HO when compared to Caucasian females (OR, 4.4; CI, 1.38–14.06). Conclusion Race is associated with different rates of severe HO formation following acetabular fracture surgery. AA patients are significantly more likely to develop severe HO following acetabular fracture surgery when compared to Caucasian patients.

This paper presents a theoretical analysis of the spatially averaged free-field responses of phase-sensitive and phase-insensitive receivers centered in the beam of a harmonically excited piston transmitter. The responses of unfocused circular plane piston receivers are analyzed, and both unfocused and spherically focused piston transmitters are considered. A set of closed-form expressions figures prominently in the analysis. The expressions are based on the Lommel diffraction formulation which is, in turn, based on the Fresnel approximation. Although approximate, the expressions allow for quick and easy estimation of phase-sensitive or phase-insensitive unfocused piston receiver responses. It is shown that the spatial averaging effects associated with phase-sensitive and phase-insensitive receivers are virtually identical when γ ≤ 0.1, where γ = b/a is the ratio of receiver radius b to transmitter radius a. In addition, numerical results obtained from the closed-form expressions are compared with previously reported results. The comparisons indicate that the approximate results are valid from the m = 3 maxima forward under the assumption of linear propagation when ka > 58, where k is the circular wave number. Finally, it is pointed out that the closed-form expressions may prove useful in the estimation of the potential for bioeffects associated with diagnostic ultrasound. (E-mail: narpci@rit.edu)

A closed-form frequency-domain formalism for spatially integrated diffraction corrections is proposed. Spatially integrated diffraction corrections are necessary when trying to characterize material with ultrasonic probing. In the case of piston transducers and point receivers, the Lommel diffraction formulation is used when the excitation is monochromatic, and the arccos diffraction formulation is used when the excitation is impulsive. The Lommel and arccos formulations are usually treated separately; here, they are connected. Specifically, the arccos diffraction formulation and Lommel diffraction formulation are shown to form an approximate Fourier transform pair. Since the Lommel formulation is amenable to closed-form spatial integration, Lommel functions are used to derive diffraction corrections for unfocused piston transducers operating in receiveonly (one-way) mode or transmit/receive (two-way) mode. Results obtained from the proposed closed-form frequency-domain formalism are qualitatively compared with results based on the closed-form time-domain or impulse-response formalism. It will be shown that the proposed frequency-domain formalism has theoretical and practical value. Finally, specific computational considerations are discussed as necessary.