Does Fracture Pattern Really Predict Displacement of LC1 Sacral Fractures?

BACKGROUND

Operative management of minimally displaced lateral compression type-1 (LC1) pelvic ring injuries remains controversial. We aimed to assess the proportion of LC1 pelvic fractures that displaced following nonoperative management as a function of specific ring fracture patterns, and we quantified the magnitude of this displacement.

METHODS

A retrospective review of the billing registry of a level-I trauma center was performed. Two hundred and seventy-three patients with a high-energy LC1 pelvic ring fracture and <5 mm of sacral displacement were included. The fracture pattern was characterized with use of computed tomography (CT) scans and radiographs. Absolute and interval pelvic ring displacement were quantified with use of previously described methodology.

RESULTS

Thirty-five pelvic ring injuries (13%) were displaced. The rate of displacement was 31% (15 of 49) for LC1 injuries involving a complete sacral fracture and bilateral ramus fractures, 12% (7 of 58) for injuries involving a complete sacral fracture and a unilateral ramus fracture, and 10% (5 of 52) for injuries involving an incomplete sacral fracture and bilateral ramus fractures. In displaced injuries, the average interval displacement was 4.2 mm (95% confidence interval [CI], 1.8 to 6.8) and the final displacement was 9.9 mm ± 4.2 mm.

CONCLUSIONS

Our study suggests that fracture characteristics can be used to predict the likelihood of displacement of LC1 fractures that are treated without surgery. To our knowledge, the present study is the first to describe the magnitude of displacement that may occur in association with LC1 pelvic ring injuries that are treated nonoperatively; however, further studies are needed to determine the clinical impact of this displacement.

LEVEL OF EVIDENCE

Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Iliac Wing Fractures: A Systematic Review of the Literature

To review the literature on iliac wing fractures to assess outcomes of operative and nonoperative treatment. A search of PubMed, MEDLINE, and Cochrane Database of Systematic Reviews was performed. Articles reporting on iliac wing fractures without pelvic ring destabilization or intraarticular extension were included. Study information and patient data were collected, and a Methodological Index for Non-randomized Studies (MINORS) score was assigned to each article. In total, 19,363 articles were identified with 32 qualifying for inclusion. The articles included 131 patients with 133 fractures. The mean age was 43.6, and mean follow-up time was 41.9 months. Forty-eight (36%) fractures were treated operatively, and 85 (64%) were treated nonoperatively. Associated injuries included bowel injuries, other pelvic fractures, gunshot wounds, and arterial injuries. There is an absence of comparative studies between operative and nonoperative management of iliac wing fractures. Indications for operative management appear to depend on comminution, open fractures, and associated injuries. (Journal of Surgical Orthopaedic Advances 32(3):139-147, 2023).

Heterotopic Ossification Prophylaxis in Acetabular Fracture Surgery: A Systematic Review

Heterotopic ossification (HO) following acetabular fracture surgery is relatively common. The purpose of this study was to perform a systematic review of the literature regarding HO rates following acetabular surgery and the effectiveness of the various prophylactic measures taken to prevent its occurrence. A search of PubMed, MEDLINE, and Cochrane Database of Systematic Reviews was performed using the search terms ("Acetabular" OR "Acetabulum") AND ("Heterotopic Ossification" OR "HO" OR "Ectopic Ossification"). Inclusion criteria included articles published in English reporting on HO in acetabular fracture surgery. Descriptive statistics were calculated with categorical data presented as frequency with percentages and continuous data as means. Standard weighted means were calculated for all parameters. Sixty-six articles were included in this study with a total of 5,028 patients. HO was identified in 1,511 (30%) of fractures. Indomethacin (27%) and radiation therapy (24%) demonstrated decreased rates of HO formation versus no prophylaxis (36%). In particular, rates of severe HO formation were substantially decreased with radiation therapy (3%) and indomethacin (7%) compared to no prophylaxis (18%). Indomethacin and radiation therapy both appear to decrease HO formation and severity without substantially increasing surgical morbidity. (Journal of Surgical Orthopaedic Advances 32(4):217-224, 2023).

Risk factors for loss to follow up of pelvis and acetabular fractures

INTRODUCTION

Pelvic and acetabular fracture incidence is increasing worldwide for more than four decades. There is currently no evidence examining risk factors for loss to follow up in patients with these injuries.

METHODS

Patients presenting with pelvic and/or acetabular fractures at our institution between 2015 and 2020 were included. Demographic, injury, treatment, and follow up information was included. Excluded patients were those who sustained a pathologic fracture, has a course of treatment prior to transfer to our centre, or expired prior to discharge.

RESULTS

446 patients, 263 with a pelvic ring injury, 172 with an acetabular fracture, and 11 with combined injuries were identified. 271 (61%) of patients in our cohort followed up in Orthopaedic clinic (p = 0.016). With an odds ratio of 2.134, gunshot wound mechanism of injury was the largest risk factor for loss to follow up (p = 0.031) followed by male sex (OR= 1.859) and surgery with general trauma surgery (OR=1.841). The most protective risk factors for follow up with Orthopaedic surgery were operatively treated pelvic and acetabular fractures (OR=0.239) and Orthopaedic Surgery as the discharging service (OR=0.372).

DISCUSSION

Numerous risk factors exist for loss to follow up including male sex, ballistic mechanism, and discharging service. Investigation into interventions to improve follow up in these patients are warranted.

A Review on Management of Insufficiency Fractures of the Pelvis and Acetabulum

"Insufficiency fractures of the pelvis and acetabulum are occurring at increasing rates. Osteoporosis is the most prevalent risk fracture. Diagnosis begins with plain radiographs followed by advanced imaging with computed tomography and/or MRI. Pelvic ring fragility injuries are classified by the Fragility fractures of the pelvis system. Elderly acetabular fractures may be classified by the Letournel system. Management of these injuries is primarily nonoperative with early immobilization when allowed by fracture characteristics. When warranted, percutaneous fixation and open reduction internal fixation are options for both. Both acute and delayed total hip arthroplasty are options for acetabular fractures."

Effects of Delayed Hip Fracture Surgery on Severely Ill Patients: Defining the Time to Medical Optimization

BACKGROUND

Patients with multiple comorbidities often have delayed hip fracture surgery due to medical optimization. The goal of this study is to identify the allowable time for medical optimization in severely ill hip fracture patients.

METHODS

The 2016-2019 NSQIP database was used to identify patients over age 60 with ASA classification scores 3 and 4 for severe and life-threatening systemic diseases. Patients were divided into immediate (<24 hours), early (24-48 hours), or late (>48 hours) groups based on time to surgery (TTS). Risk-adjusted multivariable logistic regressions were conducted to compare relationships between 30-day postoperative outcomes and TTS.

RESULTS

43,071 hip fracture cases were analyzed for the purposes of this study. Compared to patients who underwent surgery immediately, patients who had surgeries between 24 and 48 hours were associated with higher rates of pneumonia (OR 1.357, CI 1.194-1.542), UTIs (OR 1.155, CI 1.000-1.224), readmission (OR 1.136, CI 1.041-1.240), postoperative LOS beyond 6 days (OR 1.249, CI 1.165-1.340), and mortality (OR 1.205, CI 1.084-1.338). Patients with surgeries delayed beyond 48 hours were associated with higher rates of CVA (OR 1.542, CI 1.048-2.269), pneumonia (OR 1.886, CI 1.611-2.209), UTIs (OR 1.546, CI 1.283-1.861), readmission (OR 1.212, CI 1.074-1.366), postoperative LOS beyond 6 days (OR 1.829, CI 1.670-2.003), and mortality (OR 1.475, CI 1.286-1.693) compared to patients with immediate surgery.

DISCUSSION

Severely ill patients with the hip fracture may have a 24-hour window for medical optimization. Hip fracture surgery performed beyond 48 hours is associated with higher complication rates and mortality among those who are severely ill. Further prospective studies are warranted to examine the effects of early surgical intervention among severely ill patients.

Orthopaedic Surgery Residency Program Websites: A Five-Year Update and the Rise of Social Media

Objective 

The importance of online information in the form of residency program websites has been well documented. With the rise of popularity of social media, another potential vital source of online information distribution exists. We aimed to examine the changes in orthopaedic surgery residency program websites and determine the use of social media by these programs.

Methods

A list of orthopaedic residency programs was obtained. Websites were then assessed for presence of numerous criteria. The presence of a social media account on Instagram, Twitter, and Facebook platforms was then determined.

Results

One hundred ninety-five websites out of 197 programs were identified. The most commonly present criterion was resident rotation schedule with 187 (96%) listings. Meanwhile, information on virtual sessions for prospective applicants was the least present at 26 (13%). Out of the 33 criteria assessed, websites contained an average of 20.4 criteria. Approximately half of the programs were noted to have a social media presence.

Conclusion

Website utilization and accessibility have improved over time as the importance of online information has continued to grow in the orthopaedic surgery residency application process. In order to increase their online presence, numerous programs have recently created or enhanced the profiles on social media platforms which may reach more users than websites alone.

Clinical Outcomes and Surgical Complications Among Patients with Bleeding Disorders After Acute Hip Fracture Surgery

OBJECTIVE

To compare short-term (≤30 days) outcomes of hip fracture between patients with and without bleeding disorders.

DESIGN

Retrospective database review.

SETTING

The study setting included hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program database.

PATIENTS

Patients with acute hip fractures were identified from the National Surgical Quality Improvement Program database between 2016 and 2019.

INTERVENTION

Open reduction internal fixation or hemiarthroplasty.

MAIN OUTCOME MEASUREMENTS

Mortality, readmission, reoperation, length of stay, and complication were main outcome measurements.

RESULTS

There were 63,718 patients undergoing hip surgery, and 16.0% had a bleeding disorder. After adjusting for confounders, multivariable regression models showed that cases with bleeding disorders were associated with higher rates of transfusion [odds ratio (OR) 1.404; confidence interval (CI), 1.335-1.479], myocardial infarction (OR 1.367; CI, 1.190-1.572), pneumonia (OR 1.193; CI, 1.078-1.321), renal failure (OR 1.843; CI, 1.363-2.491), surgical site infections (OR 1.429; CI, 1.185-1.175), sepsis (OR 1.25; CI, 1.034-1.511), and readmission (OR 1.314; CI, 1.224-1.408). However, bleeding disorders were not associated with mortality (OR 0.947; CI, 0.866-1.036) or reoperation (OR 1.061; CI, 0.925-1.220).

CONCLUSIONS

Hip fracture surgery in patients with bleeding disorders is not associated with higher risks of short-term mortality or reoperation. However, special consideration should be taken when calculating preoperative risks of complications among bleeding disorder patients.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Algorithm Improves Acetabular Fracture Radiograph Interpretation Among Inexperienced Practitioners

Acetabular fractures are often first evaluated in the emergency department, where physicians with little experience reading pelvic radiographs may be required to make an accurate diagnosis and early management decisions. In this study, medical students classified radiographs of 20 acetabular fractures and repeated the exercise three weeks later with the aid of a previously described algorithm; half the students were given a lesson prior to using the algorithm. The pre-algorithm accuracy was 4/20 and the post-algorithm accuracy was 8.3/20 (p<0.01). The lesson provided no difference (p=0.5). This algorithm is therefore a useful reference to help classify and triage acetabular fractures.

Characteristics and Trends of Highly Cited Articles in Calcaneus Fracture Research

Background:

Despite significant effort expended toward exploring fracture patterns, surgical timing, surgical approaches, and possible implants within the calcaneus fracture literature, treatment is still fraught with complications and controversy. This study aims to conduct a citation analysis of the most cited articles related to calcaneus fractures to highlight the most historically influential articles, as well as the more recent breakthrough articles that are leading change within the field.

Methods:

A literature search was performed via Scopus on September 20, 2021 using the terms “(calcaneus OR calcaneal OR hindfoot) AND (fracture OR injury)” to search “article title, abstract, and keywords” of all primary and review articles. Search results were rigorously reviewed to ensure appropriateness for this study. The 50 highest total cited included articles were analyzed. Title, authors, journal, country of origin, institution, year of publication, citation variables (total citation count, total citation density, citation count from the last 5 years, and 5-year citation density), and level of evidence were collected for each article. One-way analysis of variance with post hoc testing was used to identify differences in citation variables and level of evidence. Pearson correlation was used to directly compare different citation variables.

Results:

The total citation count average was 178±33, with a total citation density average of 9±2. The year of publication for the 50 articles ranged from 1948 to 2014, with a median year of 1999. Roy W. Sanders was the most productive author in the field, authoring 6 articles and lead authoring 3. The most frequent level of evidence was IV with 19 articles. There was a strong correlation between total citation density and 5-year citation density. The article level of evidence showed no impact on the included measures of an article’s influence.

Conclusion:

This study successfully analyzes and presents the characteristics among the highest cited articles related to calcaneus fractures. The provided characterization of influential works and authors highlights trends, impactful findings, and future areas of focus within calcaneus fracture literature.

Level of Evidence: Review Article.

Determining the Impact of the COVID-19 Pandemic on Hand Surgery Fellowship Education

The purpose of this study is to report the impact of COVID-19 on hand surgery fellow learning and preparedness for practice. A multi-dimensional questionnaire was distributed to current hand fellows and fellowship directors across the United States. Survey questions included fellowship location, institutional response, impact on practice, education and job search. Thirty-two hand surgery fellows and 14 fellowship directors completed the survey. Of fellows, 59% reported a greater than 75% decrease in case volume. Mean hours worked per week per fellow decreased by 52%. All fellowship directors and 94% of fellows did not expect COVID-19 to impact their ability to graduate, and nearly all fellows felt prepared to start practice after fellowship training. However, many fellows expressed concern about job opportunities. The work hours and exposure of hand surgery fellows to elective surgical cases have been adversely impacted by COVID-19. Nevertheless, current hand fellows feel prepared to enter practice. (Journal of Surgical Orthopaedic Advances 31(1):048-052, 2022).

Calcaneal Reconstruction With Femoral Head Allograft Vascularized by an Osteocutaneous Medial Femoral Condyle Flap: A Case Report

CASE

A 25-year-old man presented with a closed calcaneal fracture after a 6-storey fall, complicated by osteomyelitis from fixation attempts necessitating near-complete debridement of his calcaneal tuberosity. He underwent a successful single-stage calcaneal and soft-tissue reconstruction using a femoral head structural allograft vascularized with an osteocutaneous medial femoral condyle flap. At the 18-month follow-up, his limb is largely pain-free and functional, allowing ambulation and his combined allograft-vascularized bone reconstruction shows radiographic evidence of incorporation.

CONCLUSION

Calcaneal tuberosity reconstruction with a femoral head structural allograft and vascularized bone flap is a viable option for calcaneal tuberosity bone loss because of injury/infection.

Techniques for predicting and avoiding unintentional biplanar movements during iliosacral screw placement

The technique for placing iliosacral screws typically involves the surgeon using an inlet and outlet view as the primary means for assessing the anteroposterior and craniocaudal position of the guidewire, respectively. However, because these views are rarely, if ever, orthogonal to one another, this technique will inevitably lead to unintentional biplanar movements. These unintentional movements, in turn, require correction, which can increase operating room and fluoroscopic time. Here we calculate the degree and magnitude of these unintentional movements. Additionally, we provide a simple technique for minimizing or eliminating them altogether.

Epidemiology and risk factors for loss to follow-up following operatively treated femur ballistic fractures

INTRODUCTION

Evidence regarding recommendations for treatment of ballistic fractures remains limited. This paucity of literature has largely been attributed to gunshot wound victims being a difficult population to study secondary to loss to follow-up. The purpose of this study was to examine the epidemiology of operatively treated ballistic femur fractures at our institution, the frequency of outpatient follow-up and risk factors for loss to follow-up.

METHODS

Inpatient consults from 2013-2018 were queried for femoral gunshot wounds treated operatively. Cases without internal or external fixation were excluded from the study. Postoperative visits where a patient was hospitalized or had expired were excluded from the analysis. Demographic information, length of hospital stay, and operative characteristics were compared for different fixation methods and examined as risk factors for loss to follow-up.

RESULTS

A total of 194 patients met inclusion criteria. The average age was 27 years old and 94% of the patients were male. Patient's stayed a median of 5 days post-operatively with patients treated with external fixation staying longer than internal fixation (14 days vs 5 days p=0.01). 9.3% of ballistic fractures had a concomitant vascular injury necessitating repair. 70.4% of patients attended their 2-week postoperative visit, 55.7% of patients attended their 6 week follow-up visit and 31.3% attended their 3 month follow-up visit. Risk factors for loss to follow-up at 3 month visit included younger age (p=0.028), decreased hospital length of stay (p=0.025) and intramedullary fixation (p=0.00015).

DISCUSSION AND CONCLUSION

This study reinforces the difficulty of studying ballistic fractures secondary to loss to follow-up. Younger age, shorter hospital stays and intramedullary fixation increased the risk for loss to follow-up at 3 months.

Assessing the Early Impact of the COVID-19 Pandemic on Spine Surgery Fellowship Education

STUDY DESIGN

This was a cross-sectional study.

OBJECTIVE

The objective of this study is to report the impact of COVID-19 on spine surgery fellow education and readiness for practice.

SUMMARY OF BACKGROUND DATA

COVID-19 has emerged as one of the most devastating global health crises of our time. To minimize transmission risk and to ensure availability of health resources, many hospitals have cancelled elective surgeries. There may be unintended consequences of this decision on the education and preparedness of current surgical trainees.

MATERIALS AND METHODS

A multidimensional survey was created and distributed to all current AO Spine fellows and fellowship directors across the United States and Canada.

RESULTS

Forty-five spine surgery fellows and 25 fellowship directors completed the survey. 62.2% of fellows reported >50% decrease in overall case volume since cancellation of elective surgeries. Mean hours worked per week decreased by 56.2%. Fellows reported completing a mean of 188.4±64.8 cases before the COVID-19 crisis and 84.1% expect at least an 11%-25% reduction in case volume compared with previous spine fellows. In all, 95.5% of fellows did not expect COVID-19 to impact their ability to complete fellowship. Only 2 directors were concerned about their fellows successfully completing fellowship; however, 32% of directors reported hearing concerns regarding preparedness from their fellows and 25% of fellows were concerned about job opportunities.

CONCLUSIONS

COVID-19 has universally impacted work hours and case volume for spine surgery fellows set to complete fellowship in the middle of 2020. Nevertheless, spine surgery fellows generally feel ready to enter practice and are supported by the confidence of their fellowship directors. The survey highlights a number of opportunities for improvement and innovation in the future training of spine surgeons.

LEVEL OF EVIDENCE

Level III.

Patient-Reported Outcomes Measurement Information System Correlates With Modified Harris Hip Score in Total Hip Arthroplasty

The modified Harris Hip Score (mHHS) is a validated and disease-specific instrument commonly used to assess outcomes in total hip arthroplasty (THA). The Patient-Reported Outcomes Measurement Information System (PROMIS) is a validated, computer adaptive testing (CAT)-based global health assessment tool. The authors' goal was to examine the correlation between PROMIS Pain Interference and Physical Function CATs and the mHHS in patients undergoing primary THA. All THAs were performed by 1 of 2 fellowship-trained dedicated total joint surgeons at 1 academic institution. Patients completed PROMIS and mHHS assessments preoperatively and at 3, 6, 12, and 52 weeks postoperatively. Descriptive statistics and Pearson correlation values were determined. A total of 48 patients were prospectively enrolled in the study. Preoperatively, mean total PROMIS score (Pain Interference and Physical Function) was 74.2 and mHHS was 50.8. Preoperatively, mean total PROMIS score showed a moderate correlation (r=0.56; P<.0001) with total mHHS. Postoperatively, mean total PROMIS score at 3, 6, 12, and 52 weeks was 82.4, 93.4, 100, and 100, respectively (all P<.01 vs baseline), and mHHS was 68.2, 81.1, 85.9, and 88.6, respectively (all P<.01). At 3, 6, 12, and 52 weeks postoperatively, a strong and consistent correlation was observed between the total PROMIS score and mHHS (r=0.74, 0.74, 0.73, and 0.80, respectively; all P<.0001). The PROMIS Pain Interference and Physical Function CATs accurately assessed preoperative pain and dysfunction, as well as clinical improvement following THA. Combined PROMIS Pain Interference and Physical Function is comparable to the mHHS when assessing outcome following THA for osteoarthritis. [Orthopedics. 2021;44(1):e19-e25.].

Early Response of the Orthopaedic Trauma Community to the COVID-19 Pandemic

Background

With the rise of the COVID-19 pandemic, medical systems and providers have been forced to undertake substantial changes to staffing structure, hospital policy, and surgical indications to remain able to care for patients and protect the providers. Here, we present a survey of orthopaedic trauma fellowship directors to assess when and what changes these individual units have made in order to cope with this global pandemic.

Methods

The survey was distributed via email to all 62 programs listed in the Orthopaedic Trauma Association web site.

Results

Twenty four responses were received. The majority of programs implemented changes between March 1^st and 14^th, with nearly all splitting teams into individual units, incorporating virtual sign out, and reducing the number of available, i.e. exposed, staff, fellows, and residents at any particular time.

Conclusions

These changes have been implemented in order to proactively maintain the functionality of these vital teams to patient care with no definite end point to this pandemic in sight. We hope this study provides other trauma centers and orthopaedic practices insight into possible precautions that can be taken in response to the COVID-19 pandemic.

Modern total ankle arthroplasty versus ankle arthrodesis: A systematic review and meta-analysis

The controversy in surgical management of end-stage tibiotalar arthritis with Total Ankle Arthroplasty (TAA) versus Ankle Arthrodesis (AA) has grown in parallel with the evolution of both procedures. No randomized controlled trials exist due to the vast differences in surgical goals, patient expectations, and complication profiles between the two procedures. This makes high quality systematic reviews necessary to compare outcomes between these two treatment options. The aim of this study was to provide a systematic review with meta-analysis of publications reporting outcomes, complications, and revision data following third-generation TAA and/or modern AA published in the past decade. Thirtyfive articles met eligibility criteria, which included 4312 TAA and 1091 AA procedures. This review reports data from a mean follow-up of 4.9 years in the TAA cohort and 4.0 years in the AA cohort. There was no significant difference in overall complication rate following TAA compared to AA (23.6% and 25.7% respectively, P-value 0.31). Similarly, there was no significant difference in revision rate following TAA compared to AA (7.2% and 6.3% respectively, P-value 0.65). Successful treatment of end-stage tibiotalar arthritis requires an understanding of a patients’ goals and expectations, coupled with appropriate patient selection for the chosen procedure. The decision to proceed with TAA or AA should be made on a case-by-case basis following an informed discussion with the patient regarding the different goals and complication profiles for each procedure.

Pelvic incidence in a femoroacetabular impingement population

Objective

We aim to determine if pelvic incidence (PI) differed between a symptomatic femoroacetabular impingement (FAI) population and a control.

Methods

We retrospectively identified a cohort of symptomatic FAI patients and compared measured PI to a control group.

Results

The PI was significantly lower in the FAI group compared to the control (51.32±1.07 vs. 55.63±1.04; P < 0.01).

Conclusion

The mean PI was significantly decreased in the FAI population compared to a control.

Outcomes following extra-articular fractures of the scapula: A systematic review

BACKGROUND

Scapular neck and body fractures are typically treated nonoperatively, with operative treatment traditionally focused on intraarticular fractures or double disruptions of the shoulder suspensory complex. The objective of this study was to systematically examine and compile the existing literature in regard to operative and conservative treatment of extraarticular fractures of the scapula.

METHODS

A comprehensive search of multiple electronic databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to find outcome data on fractures of the scapular neck and body. All studies from 1988 to 2018 that met inclusion criteria were reviewed independently and graded based on the modified Coleman Methodology Score. Outcomes of interest were compiled and analyzed for adjusted means.

RESULTS

42 manuscripts with a total of 669 patients were included for analysis from an initial search of 335 results. There was an average age of 41.2 years, 78.1% were male, 98.8% had a blunt force mechanism, and 66.7% had other injures outside the scapula at time of presentation. In total, there were 120 patients with scapular body fractures, 95 with scapular neck fractures, 130 with floating shoulder injuries including a scapular neck or body fracture, and 324 with an unspecified extraarticular scapular fracture. 464 patients were treated operatively, with a mean union rate of 99.4%, Constant score of 84.4, and end forward elevation of 158°. 205 total patients were treated non-operatively, with a mean union rate of 85.1%, Constant score of 79.0, and end forward elevation of 153°.

CONCLUSION

Patients with extraarticular fractures of the scapula have excellent outcomes following either nonoperative or operative management. There is a need for high quality comparative studies to determine the optimal treatment strategy for these injuries.

Factors Influencing Subspecialty Choice of Orthopedic Residents: Effect of Gender, Year in Residency, and Presumptive Subspecialty

BACKGROUND

Subspecialty training is a common part of orthopedic surgical training. The factors which influence resident subspecialty choice have important residency design and workforce implications. Our objective was to present survey data gathered from orthopedic residents regarding their fellowship plans and relative importance of factors which influence those plans.

METHODS

An anonymous online survey tool was developed and distributed to orthopedic residents through their program directors at academic institutions across the country with orthopedic surgery residency programs.

RESULTS

227 residents completed the survey. 97% planned to pursue fellowship training after residency. The most common presumptive subspecialties were sports (29.7%), joints (17.3%) and shoulder/ elbow (12.8%). The majority of senior residents (57%) reported that their subspecialty choice had changed during residency. When making their choice of subspecialty, residents were most influenced by their experiences working on the subspecialty service in question, their experiences working with a mentor, and intellectual interest. The factors influencing their choice were affected by gender, residency year and presumptive subspecialty.

CONCLUSIONS

The most critical factors influencing subspecialty choice of orthopedic residents included experiences in rotations as a resident, intellectual interest and mentors in certain subspecialties. Factors influencing subspecialty choice changes over the course of residency and differ between male and female residents. This information may be useful for residency design, mentorship structuring, career counseling and for addressing subspecialty surpluses or shortages which arise in the future.Level of Evidence: IV.

Prosthesis-Engaging Retrograde Femoral Nail with Locking Plate for the Treatment of a Vancouver B1 Periprosthetic Femur Fracture Nonunion: A Case Report

CASE

Here, we describe a case of a Vancouver B1 periprosthetic femur fracture which initially went on to nonunion after open reduction and internal fixation. Union was ultimately achieved with a construct consisting of a prosthesis-engaging retrograde femoral nail and a locking compression plate.

CONCLUSIONS

This case provides evidence that a construct consisting of a prosthesis-engaging retrograde femoral nail and a locking compression plate is an option for increasing fracture site stability in Vancouver B1 periprosthetic fractures and may be useful for patients with poor bone quality or a previously established nonunion.

Arthroscopy versus arthrotomy for the treatment of septic knee arthritis

Purpose

To compare complications following arthroscopy and arthrotomy for treatment of septic knee arthritis.

Methods

Patients undergoing arthroscopy and arthrotomy for a diagnosis of septic knee arthritis were identified in National Surgical Quality Improvement Program and placed in a multivariate analysis to determine if type of surgery contributed to postoperative complications.

Results

Knee arthrotomy was associated with an increased risk for increased operative time [Parameter estimate 4.555 (95% CI:3.023-6.085); p < 0.0001], minor morbid events [OR 2.064 (95% CI: 1.447-2.943); p < 0.0001], and any morbidity [OR 2.285 (95% CI:1.527-3.419); p < 0.0001].

Conclusions

Knee arthrotomy was associated with a higher risk of complications.

The Experiential Benefit of an Orthopedic Trauma Fellowship: An Analysis of ACGME Case Log Data From 2006 to 2017

OBJECTIVE

The Accreditation Council for Graduate Medical Education (ACGME) has published orthopedic case log data since the 2006/2007 academic year. Here, we use this data to analyze the variability in orthopedic trauma case experience reported by orthopedic trainees and to better understand the impact of an orthopedic trauma fellowship on orthopedic surgical training.

DESIGN, SETTING, AND PARTICIPANTS

Data were gathered from ACGME case log reports for orthopedic residents (reporting the cumulative case experience of graduating residents) and orthopedic trauma fellows (reporting the case experience of their fellowship year only) for all available years.

RESULTS

The average orthopedic trauma fellow reported significantly more trauma cases in multiple body regions ("Pelvis/Hip", "Femur/Knee", and "Foot/Toes") and "Open Complex" reductions (as defined by the ACGME) in their 1 year of fellowship than the average resident reported in their 5 years of residency.

CONCLUSION

On average, orthopedic trauma fellowships substantially increase the trauma case volumes of orthopedic trainees, especially with respect to lower extremity trauma.

Novel Treatment for Recurrent Posttraumatic Hip Instability: A Case Report

CASE

A 26-year-old woman sustained a traumatic right hip dislocation with posterior wall component in a motor vehicle collision. Initial treatment consisted of open reduction internal fixation of her posterior wall fracture. Six years later, she developed low-energy recurrent hip instability. Imaging demonstrated posterior capsular insufficiency and femoral retrotorsion. The patient underwent intertrochanteric femoral rotational osteotomy. Nine years postoperatively, the patient has returned to activity without restriction or subsequent dislocations.

CONCLUSIONS

Recurrent posttraumatic hip instability requires careful identification of the etiology of instability. This case provides long-term follow-up after successful treatment with intertrochanteric femoral rotational osteotomy.

Single-Use Custom Instrumentation in Total Knee Arthroplasty: Effect on In-Hospital Complications, Length of Stay, and Discharge Disposition

Total knee arthroplasty (TKA) is a quality surgical intervention with rapidly increasing use. This growth has brought with it a host of new technologies, including custom instrumentation (CI). With the current emphasis on value-based health care, the clinical benefit of CI TKA must be evaluated. The goal of this study was to compare CI and conventional TKA regarding multiple quality metrics, in-hospital complications, length of stay, and discharge destination. The authors propensity score matched 231 conventional TKAs to 231 consecutive CI TKAs for age, sex, and body mass index. Preoperative risk factors analyzed were age, sex, body mass index, and preoperative hemoglobin. Perioperative factors included transfusion rate, hemoglobin drop, hemovac output, operative time, length of stay, discharge disposition, deep venous thrombosis and pulmonary embolism rates, and in-hospital vital sign data. There were no differences in preoperative demographics between groups. Postoperatively, there was no difference between conventional and CI TKA in operative time, transfusion rate, discharge hemoglobin, length of stay, discharge disposition, or in-hospital venous thromboembolism rates. In the conventional and CI groups, length of stay was 2.6 and 2.5 days (P=.43) and discharge disposition was 82% home and 83% home (P=.90), respectively. Although CI TKA is commonly implemented, in this analysis, compared with conventional TKA, it was not associated with any difference in length of stay, discharge disposition, operative time, transfusion rate, or in-hospital complications. [Orthopedics. 2019; 42(5):299-303.].

Cognitive Apprenticeship in Orthopaedic Surgery: Updating a Classic Educational Model

OBJECTIVE

To define cognitive apprenticeship and describe how it can be applied to orthopedic education.

DESIGN

Traditional apprenticeships have been used through history as a teaching model for wide variety of skills. These apprenticeships are characterized by practical, on-the-job training in which the apprentice observes and assists a master in the completion of a task, and thereby learns the skills needed to complete that task on his or her own.

RESULTS

Cognitive apprenticeship is differentiated from the traditional apprenticeship model primarily by its educational goals. Cognitive apprenticeships are used to teach skills which require internal though processes which cannot be readily observed externally by the teacher or the student.

CONCLUSION

Here, we review the history of the cognitive apprenticeship concept, its basic principles, its applications to a wide variety of educational circumstances, and its potential use a framework for developing orthopedic curricula.

Deltoid ligament repair reduces and stabilizes the talus in unstable ankle fractures

Introduction

Treatment of supination external rotation type IV (SER-IV) ankle injuries has focused on reduction and fixation of the fibula and syndesmosis (ORIF), not repair of the deltoid ligament.

Methods

Twenty-one ankles were analyzed with a motion capture system. Uninjured ankles were stressed and compared to ankles with SER-IV injuries, then with ORIF, and finally ORIF and deltoid repair.

Results

After deltoid ligament repair, talar coronal and axial rotation normalized to the uninjured state and were significantly reduced compared to ORIF alone.

Discussion

Deltoid ligament repair after an SER-IV ankle injury can help directly reduce and stabilize the tibiotalar joint.

The Relevance of the Judet and Letournel Acetabular Fracture Classification System in the Modern Era: A Review

The Judet and Letournel acetabular fracture classification system, based on the idea of bicolumnar support of the acetabulum, was first described in a landmark article published in the 1960s. It has stood the test of time and continues to be the preferred method for describing acetabular fractures for the majority of orthopaedic trauma surgeons. Still, there have been attempts to modify or replace Letournel system since its introduction for a variety of reasons, chief among them a perceived inability of the classification system to account for a number of transitional fracture patterns and injury modifiers that may affect surgical decision making and patient outcomes. In this review, we present the literature related to the Judet and Letournel acetabular fracture classification system, over 50 years after its first formal description. We summarize its strengths, weaknesses, and its place in our current understanding of acetabular fractures and their recommended management.

Long leg splinting for pediatric femur fractures

Background

Pediatric femur fractures are frequently encountered injuries frequently treated with spica casting. Spica casting may, however, be expensive and burdensome to patients. A possible alternative is a long leg splint.

Methods

Patients aged 6 months to 5 years old who were treated for a femoral shaft fracture with a long leg splint extending above the waist were matched with a patient treated with a spica cast.

Results

At the time of healing, the alignment in the spica cast group was only significantly better than the alignment of the splint group with respect to coronal angulation.

Valgus Osteotomy with Plate-and-Nail Fixation for the Treatment of Proximal Femoral Deformities Due to Fibrous Dysplasia: A Report of Two Cases

CASE

We describe 2 cases of proximal femoral deformity due to fibrous dysplasia that were corrected with osteotomies and a novel combined construct with a blade plate and a retrograde intramedullary nail.

CONCLUSION

A single-stage procedure using a combined construct with a blade plate and a retrograde intramedullary nail is a viable option for correcting and subsequently preventing proximal femoral deformities due to fibrous dysplasia.

Early diagnosis of septic arthritis in immunocompromised patients

OBJECTIVES

Septic arthritis results in rapid joint destruction if not properly diagnosed and treated. A work up for septic arthritis includes a peripheral white blood cell count, inflammatory markers, and a joint aspiration. In the general population, the interpretation of these labs has been well-defined by prior studies. To this point, no study has determined how immunosuppressive states affect this work up.

METHODS

Patients with immunosuppressive conditions who received a joint aspiration for a painful joint were retrospectively identified. Laboratory results from their work up were gathered and analyzed.

RESULTS

216 patients were included in the study, 21 of whom were diagnosed with septic arthritis. The average aspiration WBC count was 74,190 with 88% PMNs. 81% had a positive gram stain.

DISCUSSION

Laboratory values for immunosuppressed patients with septic arthritis were similar to those associated with septic arthritis in historical general population controls.

Simulation-Based Educational Module Improves Intern and Medical Student Performance of Closed Reduction and Percutaneous Pinning of Pediatric Supracondylar Humeral Fractures

BACKGROUND

Simulation-based education has been integrated into many orthopaedic residency programs to augment traditional teaching models. Here we describe the development and implementation of a combined didactic and simulation-based course for teaching medical students and interns how to properly perform a closed reduction and percutaneous pinning of a pediatric supracondylar humeral fracture.

METHODS

Subjects included in the study were either orthopaedic surgery interns or subinterns at our institution. Subjects all completed a combined didactic and simulation-based course on pediatric supracondylar humeral fractures. The first part of this course was an electronic (e)-learning module that the subjects could complete at home in approximately 40 minutes. The second part of the course was a 20-minute simulation-based skills learning session completed in the simulation center. Subject knowledge of closed reduction and percutaneous pinning of supracondylar humeral fractures was tested using a 30-question, multiple-choice, written test. Surgical skills were tested in the operating room or in a simulated operating room. Subject pre-intervention and post-intervention scores were compared to determine if and how much they had improved.

RESULTS

A total of 21 subjects were tested. These subjects significantly improved their scores on both the written, multiple-choice test and skills test after completing the combined didactic and simulation module. Prior to the module, intern and subintern multiple-choice test scores were significantly worse than postgraduate year (PGY)-2 to PGY-5 resident scores (p < 0.01); after completion of the module, there was no significant difference in the multiple-choice test scores. After completing the module, there was no significant difference in skills test scores between interns and PGY-2 to PGY-5 residents. Both tests were validated using the scores obtained from PGY-2 to PGY-5 residents.

CONCLUSIONS

Our combined didactic and simulation course significantly improved intern and subintern understanding of supracondylar humeral fractures and their ability to perform a closed reduction and percutaneous pinning of these fractures.

Total ankle arthroplasty versus ankle arthrodesis-a comparison of outcomes over the last decade

BACKGROUND

The surgical treatment of end-stage tibiotalar arthritis continues to be a controversial topic. Advances in surgical technique and implant design have lead to improved outcomes after both ankle arthrodesis (AA) and total ankle arthroplasty (TAA), yet a clear consensus regarding the most ideal form of treatment is lacking. In this study, the outcomes and complications following AA and TAA are compared in order to improve our understanding and decision-making for care and treatment of symptomatic tibiotalar arthritis.

METHODS

Studies reporting on outcomes and complications following TAA or AA were obtained for review from the PubMed database between January 2006 and July 2016. Results from studies reporting on a minimum of 200 total ankle arthroplasties or a minimum of 80 ankle arthrodesis procedures were reviewed and pooled for analysis. All studies directly comparing outcomes and complications between TAA and AA were also included for review. Only studies including modern third-generation TAA implants approved for use in the USA (HINTEGRA, STAR, Salto, INBONE) were included.

RESULTS

A total of six studies reporting on outcomes following TAA and five reporting on outcomes following AA met inclusion criteria and were included for pooled data analysis. The adjusted overall complication rate was higher for AA (26.9%) compared to TAA (19.7%), with similar findings in the non-revision reoperation rate (12.9% for AA compared to 9.5% for TAA). The adjusted revision reoperation rate for TAA (7.9%) was higher than AA (5.4%). Analysis of results from ten studies directly comparing TAA to AA suggests a more symmetric gait and less impairment on uneven surfaces after TAA.

CONCLUSIONS

Pooled data analysis demonstrated a higher overall complication rate after AA, but a higher reoperation rate for revision after TAA. Based on the existing literature, the decision to proceed with TAA or AA for end-stage ankle arthritis should be made on an individual patient basis.

Novel intramedullary device for lengthening transfemoral residual limbs

Background

Lower limb loss is a highly disabling medical condition that can severely impact a person’s quality of life. Recovery becomes especially challenging if an amputee has a short residual limb, which can complicate proper prosthetic fitting, causing discomfort, difficulties in suspension, and reduced mobility. Current limb lengthening techniques such as the Ilizarov apparatus and external fixators are cumbersome, uncomfortable, and have high complication rates. In this study, we investigated the effectiveness of a novel limb-lengthening device that uses intramedullary bone lengthening and requires only one percutaneous rod at the end of the limb during the distraction phase. Only the intramedullary nail remains after the distraction phase, and no external components are required during the consolidation phase. We hypothesize that this system would create a much easier experience for the patient.

Methods

The system was first tested in a mock surgical implantation using plastic femur bones. The device was then tested in a series of cadaveric experiments using pelvis-to-knee specimens by a group of surgeons. Surgeons evaluated the surgical insertion technique, soft tissue considerations, hardware fixation strategies, and the effectiveness of the distraction mechanism. Revisions and improvements to the device and surgical procedure were made based on the results from the cadaveric experiments.

Results

A questionnaire was given to two visiting surgeons following the final iteration of the device. The surgeons reported that the system effectively lengthened the limb, was sturdy, and could be installed efficiently. However, there remains a risk of infection and soft tissue imbalances, similar to that introduced by an external fixator device. Suggestions on how to improve the design of the device and mitigate infection through postoperative management and surgical standard of care will be considered for future clinical trials.

Conclusions

The described intramedullary residual limb-lengthening device has evolved from a prototype to a mature model tested in six cadaveric experiments to date. Further mechanical and functional testing is needed to finalize the device before testing in patients.

Weight cycling, psychological health, and binge eating in obese women

This study examined the relationship between weight cycling and psychological health in 120 obese women. Weight cycling was defined in 2 ways by retrospective self-report: total lifetime weight loss and total number of weight cycles > or = 20 lbs (> or = 9.07 kg). Psychological self-report measures assessed psychiatric symptoms, eating behavior, mood, stress, and perceptions of physical health. Of the 52 associations between weight cycling and psychological parameters, 8 were significant, with the most consistent association being between weight cycling and binge eating. Binge eating was also strongly associated with psychological distress, as found in previous studies. After adjusting for binge eating, however, weight cycling was independently related to only one of the psychological measures: perceived physical health.

Weight cycling, psychological health, and binge eating in obese women

This study examined the relationship between weight cycling and psychological health in 120 obese women. Weight cycling was defined in 2 ways by retrospective self-report: total lifetime weight loss and total number of weight cycles > or = 20 lbs (> or = 9.07 kg). Psychological self-report measures assessed psychiatric symptoms, eating behavior, mood, stress, and perceptions of physical health. Of the 52 associations between weight cycling and psychological parameters, 8 were significant, with the most consistent association being between weight cycling and binge eating. Binge eating was also strongly associated with psychological distress, as found in previous studies. After adjusting for binge eating, however, weight cycling was independently related to only one of the psychological measures: perceived physical health.

Effect of the number of high-fat and low-fat cues on food choice

This study examined the effects on food choice of increasing the number of healthy items available (fruit) and decreasing the number of unhealthy items available (candy bars). A similar choice, involving nonfood items, was also examined. Two hundred eighty-nine men and women were randomly assigned to 1 of 4 experimental groups: (a) control group, (b) increased number of fruits, (c) decreased number of candy bars, and (d) combination. Between 30% and 40% of participants chose fruit regardless of the amount of fruit and candy presented: there was no effect of increasing fruit or decreasing candy bars. However, restrained participants and current dieters were more likely to choose fruit. In contrast, both stimulus control techniques were effective in increasing the percentage of participants choosing a nonfood item. These results suggest that stimulus control may not be sufficient to modify food choice: other powerful factors affect eating behavior, and these must be considered.

Prescribing exercise in multiple short bouts versus one continuous bout: effects on adherence, cardiorespiratory fitness, and weight loss in overweight women

OBJECTIVE

To investigate whether prescribing exercise in several short-bouts versus one long-bout per day would enhance exercise adherence, cardiorespiratory fitness, and weight loss in overweight adult females in a behavioral weight control program.

DESIGN

Randomized controlled trial with subjects randomized to either a short-bout exercise group (SB, n = 28, age = 40.4 +/- 5.9 yrs) or a long-bout exercise group (LB, n = 28, age = 40.9 +/- 7.3 yrs), with subjects followed for a period of 20 weeks. Both groups were instructed to exercise 5 days per week with exercise duration progressing from 20 to 40 min per day. The LB group performed one exercise bout per day, whereas the SB group performed multiple 10 min bouts of exercise per day. The recommended caloric intake for all subjects was 5022-6277 kJ/day (1200-1500 kcal/day), with fat reduced to 20% of caloric intake.

SUBJECTS

Fifty-six obese, sedentary females (BMI = 33.9 +/- 4.1 kg/m2).

MEASUREMENTS

Exercise participation was assessed from self-reported diaries and Tri-Trac Accelerometers. Cardiorespiratory fitness was assessed using a submaximal cycle ergometer test.

RESULTS

Exercising in multiple short-bouts per day improved adherence to exercise: the SB group reported exercising on a greater number of days (mean +/- s.d. = 87.3 +/- 29.5 days vs 69.1 +/- 28.9 days; P < 0.05) and for a greater total duration (223.8 +/- 69.5 min/week vs 188.2 +/- 58.4 min/week; P = 0.08) than the LB group. Predicted VO2Peak increased by 5.6% and 5.0% for the LB and SB groups, respectively (P < 0.05). There was a trend for the weight loss to be greater in the SB group (-8.9 +/- 5.3 kg) compared to the LB group (-6.4 +/- 4.5 kg; P < 0.07).

CONCLUSION

These results suggest that short-bouts of exercise may enhance exercise adherence. Short-bouts of exercise may also enhance weight loss and produce similar changes in cardiorespiratory fitness when compared to long-bouts of exercise. Thus, short-bouts of exercise may be preferred when prescribing exercise to obese adults.

Effects of a behavioral weight loss program stressing calorie restriction versus calorie plus fat restriction in obese individuals with NIDDM or a family history of diabetes

OBJECTIVE

The aim of this randomized trial was to compare the effects of a behavioral intervention focusing on either calorie restriction alone or calorie plus fat restriction on weight loss and changes in lipids and glycemic control in individuals with non-insulin-dependent diabetes mellitus (NIDDM) or a family history of diabetes.

RESEARCH DESIGN AND METHODS

We recruited 44 obese women with NIDDM and 46 obese women with a family history of NIDDM and randomly assigned these subjects to calorie restriction (CAL) or to calorie plus fat restriction (CAL + FAT). All subjects participated in a 16-week behavioral weight loss program, with training in diet, exercise, and behavior modification. Subjects assigned to the CAL condition were given a 1,000-1,500 kcal/day goal and self-monitored calories consumed. Subjects assigned to the CAL+FAT condition had the same calorie goal, but were also given a fat goal (grams of fat/day), to produce a diet with < 20% of calories from fat; this group monitored both calories and fat grams.

RESULTS

Among NIDDM subjects, weight loss of the subjects in the CAL+FAT condition was significantly greater than subjects in the CAL condition (7.7 vs. 4.6 kg) and the CAL+FAT condition group also maintained their weight loss better at the 1-year follow-up (5.2 vs. 1.0 kg). Significant decreases in glucose, high-density lipoprotein (HDL) cholesterol, and total cholesterol were seen after 16 weeks of treatment among NIDDM subjects; these changes were similar in CAL and CAL+FAT groups, but a greater proportion of subjects in CAL condition required oral hypoglycemic medication. At the 1-year follow-up, all parameters had returned to baseline. No significant differences in weight loss or physiological changes were seen between CAL and CAL+FAT conditions in subjects with a family history of diabetes.

CONCLUSIONS

These results suggest that using the combination of calorie and fat restriction may help promote weight loss in obese NIDDM patients. No other long-term benefits of this regimen were observed.

The Drosophila segmentation gene runt has an extended cis-regulatory region that is required for vital expression at other stages of development

The Drosophila runt gene functions in several developmental pathways during embryogenesis. This gene was initially characterized due to the pivotal role that it plays in the genetic regulatory network that establishes the segmented body pattern. Recently it was found that this X-chromosome-linked gene is one of several dosage-sensitive, X-linked components that is involved in activating the Sex-lethal gene in blastoderm stage female embryos. Finally, this gene is also extensively re-expressed in later stages of embryogenesis in the developing nervous system where it plays an important role in the development of specific neural lineages. We have initiated an analysis of the runt cis-regulatory region in order to investigate runt's roles in these (and other) developmental pathways. Analysis of both the function and the expression patterns of runt genes with truncated cis-regulatory regions indicates that there are multiple elements that make quantitative contributions to runt regulation during segmentation. We find that sequences that are more than 8.5 kb upstream of the runt promoter are necessary for normal expression during the post-blastoderm stages of embryogenesis. Genetic experiments indicate that the post-blastoderm expression of runt is vital to the organism.

Nutritional management of catabolic acute renal failure requiring renal replacement therapy

Catabolic acute renal failure patients have a high incidence of morbidity and mortality despite advances in dialytic and lifesaving technologies. Malnutrition is a complicating factor in the treatment of these patients. Early and aggressive nutritional support may positively impact eventual outcome. Continuous renal replacement therapy (CRRT) enables delivery of this support. This article reviews nutritional support in acute renal failure for individuals undergoing these therapies.

Overlapping genes of Drosophila melanogaster: organization of the z600-gonadal-Eip28/29 gene cluster

The Drosophila gonadal (gdl) gene is a member of a gene cluster that maps cytogenetically to the 71CD interval of chromosome 3. The gene is bordered distally by z600, a gene expressed predominantly during early embryogenesis, and proximally by Eip28/29, a gene regulated by ecdysone in Drosophila cell lines. gdl can be expressed in either of two modes in adults: gdlF expression leads to the transcripts 1300 and 1000, which are found in the ovaries, whereas gdlM expression leads to the transcripts 1500 and 1200, which are found in the testes. In situ hybridization analysis reveals that this expression occurs in the germ line during oogenesis and spermatogenesis. Structural studies identify an unusual gdl sequence organization. The ovarian and testes transcripts differ at their 5' ends because of the utilization of different transcription initiation sites. This result indicates that alternative promoter usage is responsible for sex-specific gdl expression. Within an expression mode, the two transcripts differ at their 3' ends as a result of multiple polyadenylation site usage; one of these sites resides within the 5' exon of the Eip28/29 gene. gdl is overlapped by z600 as well because the z600 transcript is polyadenylated at position +91 of the gdlM transcripts. An analysis of germ-line transformants reveals that gdl can be expressed properly outside the overlapping gene environment because a 1.8-kb DNA region contains all the sequences necessary for gdl sex-specific expression.

Isolation of the Drosophila segmentation gene runt and analysis of its expression during embryogenesis

runt is one of the genes required for establishment of the segmented body pattern of the Drosophila embryo. We have isolated DNA sequences containing this gene using P-element transposon tagging. Southern blot analyses of six different DNA rearrangements that are associated with runt mutations revealed a minimal region of 8.5-kb of DNA that was important for function. In germ line transformation experiments, a 14.5-kb segment of DNA that spanned this minimal region provided significant, although not full, levels of runt activity. The runt gene encoded a 2.6-kb poly(A)+ RNA that underwent a series of dynamic changes in its spatial and temporal patterns of accumulation during embryogenesis. The runt RNA was most abundant at the blastoderm stage when it showed the seven stripes of expression characteristic of other Drosophila pair-rule genes.