A case of congenital pili multigemini.

Pili multigemini is an uncommon hair follicle disorder, where multiple hair shafts emerge from the same follicular opening. While it is commonly observed in men's facial hair, it has also been reported, albeit infrequently, in other areas of the body. Here we describe an unusual case of congenital pili multigemini presenting on the eyebrow of a female infant.

Disseminating evidence in medical education: journal club as a virtual community of practice.

BACKGROUND: This study explores the impacts of the Council on Medical Student Education in Pediatrics (COMSEP) Journal Club, a unique means of providing monthly professional development for a large international community of pediatric undergraduate medical educators. In particular, we sought to establish member engagement with the Journal Club, identify factors impacting member contributions to the Journal Club, and determine perceived benefits of and barriers to participation as a Journal Club reviewer. METHODS: Using an established Annual Survey as a study instrument, six survey questions were distributed to members of COMSEP. Items were pilot tested prior to inclusion. Quantitative data were analyzed using descriptive statistics and chi-square analysis.. RESULTS: Of 125 respondents who completed the survey, 38% reported reading the Journal Club most months or always. Level of engagement varied. Reasons for reading included a topic of interest, keeping up to date on medical education literature, gaining practical tips for teaching and implementing new curricula. Motivators for writing a review included keeping up to date, contributing to a professional organization, and developing skill in analyzing medical education literature, with a minority citing reasons of enhancing their educational portfolio or academic promotion. The most commonly cited barriers were lack of time and lack of confidence or training in ability to analyze medical education literature. CONCLUSION: As a strategy to disseminate the latest evidence in medical education to its membership, the COMSEP Journal Club is effective. Its format is ideally suited for busy educators and may help in members' professional development and in the development of a community of practice.

The Stability of Fixation of Vancouver B2 Periprosthetic Femoral Fractures: Effect of Implantation Technique.

BACKGROUND: Due to increasing volume of total hip arthroplasties, periprosthetic femoral fractures have become a common complication with increased revision burden and perioperative morbidity. The objective of this study was to evaluate the fixation stability of Vancouver B2 fractures treated with 2 techniques. METHODS: A common B2 fracture was created by reviewing 30 type B2 cases. The fracture was then reproduced in 7 pairs of cadaveric femora. The specimens were divided into 2 groups. In Group I ("reduce-first"), the fragments were reduced first, followed by implantation of a tapered fluted stem. In Group II ("ream-first"), the stem was implanted in the distal femur first, followed by fragment reduction and fixation. Each specimen was loaded in a multiaxial testing frame with 70% of peak load during walking. A motion capture system was used to track the motion of the stem and fragments. RESULTS: The average stem diameter in Group II was 16.1 ± 0.4 mm, versus 15.4 ± 0.5 mm in Group I. The fixation stability was not significantly different in the 2 groups. After the testing, the average stem subsidence was 0.36 ± 0.31 mm and 0.19 ± 0.14 mm (P = .17) and the average rotation was 1.67 ± 1.30° and 0.91 ± 1.11° (P = .16) in Groups I and II, respectively. Compared to the stem, there was less motion of the fragments and there was no difference between the 2 groups (P > .05). CONCLUSIONS: When tapered fluted stems were used in combination with cerclage cables for treatment of Vancouver type B2 periprosthetic femoral fractures, both the "reduce-first" and "ream-first" techniques showed adequate stem and fracture stability.

Micromotion and Migration of Cementless Tibial Trays Under Functional Loading Conditions.

BACKGROUND: The outcome of cementless total knee arthroplasty (TKA) relies on successful bony ingrowth into the implant surfaces. Failures due to aseptic loosening are still reported, especially in younger and more active patients. The objective of this study is to quantify the micromotion of a commercially available design of cementless tibial tray under loading conditions simulating walking and stair descent. METHOD: A commercially available design of cementless total knee arthroplasty was implanted in 7 cadaveric knees which were preconditioned with 500 cycles of 0°-100° flexion under a vertical load of 1050 N in a custom-built, multiaxial functional activity simulator. This was followed by application of the peak forces and moments occurring during walking and stair descent. During each loading procedure, 3-dimensional motion at the bone-prosthesis interface was measured using digital image correlation. RESULTS: The tray migrated 101 ± 25 µm on average during preconditioning, which was dominated by rotation in the sagittal plane (92% of total migration), combined with posterior translation (28%) and minimal rotation in the transverse plane (14%). The migration varied 2.7-fold (61-167 µm) between the 6 measurement zones. Stair descent produced significantly higher total micromotion than walking in zone #5 (62 ± 9 vs 51 ± 10 µm, P < .05) and zone #6 (68 ± 17 vs 37 ± 10 µm, P < .05). In addition, during stair descent, the tray exhibited significantly more tilting (anterior zones: 31 ± 17 vs -16 ± 20 µm, P < .05; posterior zones: -60 ± 8 vs -40 ± 7 µm, P < .05) and more anteroposterior displacement in the anterior zones (-25 ± 3 vs -13 ± 2 µm, P < .05) when compared to walking. CONCLUSION: The relative motion at the bone-prosthesis interface varied substantially around the periphery of the cementless tray. Under the loading conditions evaluated, the tray primarily underwent a rocking motion in the sagittal plane. Compared with walking, stair descent produced significantly more micromotion, especially in the posterior zones.

Relation between right ventricular wall stress, fibrosis, and function in right ventricular pressure loading.

Right ventricle (RV) pressure loading can lead to RV fibrosis and dysfunction. We previously found increased RV, septal hinge-point and left ventricle (LV) fibrosis in experimental RV pressure loading. However, the relation of RV wall stress to biventricular fibrosis and dysfunction is incompletely defined. Rabbits underwent progressive pulmonary artery banding (PAB) over 3 wk with hemodynamics, echocardiography, and myocardial samples obtained at a terminal experiment at 6 wk. An additional group received PAB and treatment with an endothelin receptor antagonist. The endocardial and epicardial borders of short-axis echo images were traced and analyzed with invasive pressures to yield regional end-diastolic (ED) and end-systolic (ES) wall stress. To increase clinical translation, computer model-derived wall stress was compared with Laplace wall stress. The relation of wall stress with fibrosis (picrosirius red staining) and ventricular function was analyzed. ED wall stress in all regions and RV and LV free-wall ES wall stress were increased in PAB rabbits versus sham animals. Laplace wall stress correlated well with computational models. In PAB, fibrosis was highest in the RV free wall, then septal hinge regions, and lowest in the septum and LV free wall. Fibrosis was moderately related to ED (r = 0.47, P = 0.0011), but not ES wall stress. RV ED wall stress was strongly related to echo indexes of function (strain rate: r = 0.71, P = 0.048; E', r = -0.75, P = 0.0077; tricuspid annular plane systolic excursion: r = 0.85, P = 0.0038) and RV fractional area change (r = 0.77, P = 0.027). ED, more than ES, wall stress is related moderately to fibrosis and strongly to function in experimental RV pressure loading, especially at the septal hinge-point regions, where fibrosis is prominent. This suggests that wall stress partially links RV pressure loading, fibrosis, and dysfunction and may be useful to follow clinically.NEW & NOTEWORTHY Biventricular fibrosis and dysfunction impact outcomes in RV pressure loading, but their relation to wall stress is poorly defined. Using a pulmonary artery band rabbit model, we entered echocardiography and catheter data into a computer model to yield regional end-diastolic (EDWS) and end-systolic (ESWS) wall stress. EDWS, more than ESWS, correlated with fibrosis and dysfunction, especially at the fibrosis-intense septal hinge-point regions. Thus, wall stress may be clinically useful in linking RV pressure loading to regional fibrosis and dysfunction.

Will New Metal Heads Restore Mechanical Integrity of Corroded Trunnions?

BACKGROUND: Metal wear and corrosion from modular junctions in total hip arthroplasty can lead to further unwanted surgery. Trunnion tribocorrosion is recognized as an important contributor to failure. This study was performed to determine if new metal heads restore mechanical integrity of the original modular junction after impaction on corroded trunnions, and assess which variables affect stability of the new interface created at revision total hip arthroplasty. METHODS: Twenty-two trunnions, cobalt-chromium (CoCr) and titanium alloy (TiAIV), (CoCr, n = 12; TiAIV, n = 10) and new metal heads were used, 10 trunnions in pristine condition and 12 with corrosion damage. Test states were performed using an MTS Machine and included the following: 1, Assembly; 2, Disassembly; 3, Assembly; 4, Toggling; and 5, Disassembly. During loading, three-dimensional motion of the head-trunnion junction was measured using a custom jig. RESULTS: There were no statistical differences in the tested mechanical properties between corroded and pristine trunnions implanted with a new metal femoral head. Average micromotion of the head versus trunnion interface was greatest at the start of loading, stabilizing after approximately 50 loading cycles at an average of 30.6 ± 3.2 µm. CONCLUSION: Corrosion at the trunnion does not disrupt mechanical integrity of the junction when a CoCr head is replaced with a CoCr trunnion. However, increased interface motion of a new metal head on a corroded titanium trunnion requires additional study. The evaluation of ball head size on mechanical integrity of trunnions would also be a potential subject of future investigation, as increasing the ball head size at the time of revision is not uncommon in revisions today.

Anteroposterior Knee Stability During Stair Descent.

This study examined the influence of tibio-femoral conformity on anteroposterior (AP) knee stability during stair descent, particularly with a dished cruciate sacrificing (CS) design. A joint simulator simulated stair descent of cadaveric knees. Tibio-femoral displacement was measured. Knees were tested in intact, ACL-deficient, and TKA with cruciate-retaining (CR), CS and posterior-stabilizing (PS) inserts. Loading during stair descent simulation caused femur displacement anteriorly prior to quadriceps contraction. Quadriceps contraction reestablished the initial femoral AP position. During simulated stair descent, AP stability was restored using PS, CR or CS inserts with an intact PCL. The CS design without the PCL did not provide AP stability. Increasing quadriceps force to restore AP stability may explain the clinical findings of pain and fatigue experienced by some patients after TKA.

Impact of Prophylactic Cerclage Location on Femoral Fracture Propagation: A Biomechanical Study.

OBJECTIVES: Prophylactic cerclage cables are often placed intraoperatively about a fracture to prevent propagation. However, biomechanical data supporting optimal cable placement location are lacking. The objective of this study was to evaluate the impact of prophylactic cerclage placement location on the propagation of femoral shaft fractures. METHODS: The diaphysis of 14 fresh-frozen cadaveric femora were included. Volumetric bone mineral density in the femoral shaft was obtained from quantitative computed tomography scans. For each specimen, a 5-mm longitudinal fracture was created proximally to simulate a pre-existing fracture. After reaming of the femoral canal, a 3 degrees tapered wedge was advanced with an MTS machine at 0.2 mm/s until failure. The tests were conducted with a CoCr cable placed at varying distances (5 mm, 10 mm, 15 mm, 20 mm, and cableless) from the distal tip of the initial fracture. A compression loadcell was used to measure the cable tension during the tests. The axial force, displacement, and cable tension were monitored for comparison between groups. RESULTS: In the cableless group, the mean force needed to propagate the fracture was 1017.8 ± 450.3 N. With the addition of a cable at 5 mm below the fracture, the failure force nearly doubled to 1970.4 ± 801.1 N (P < 0.001). This also led to significant increases in stiffness (P = 0.006) and total work (P = 0.001) when compared with the control group. By contrast, in the 15 and 20 mm groups, there were no significant changes in the failure force, stiffness, and total work as compared with the control group (P > 0.05). CONCLUSIONS: Propagation of femoral shaft fracture was effectively resisted when a prophylactic cable was placed within 5 mm from the initial fracture, whereas cables placed more than 10 mm below the initial fracture were not effective in preventing fracture propagation.

Correction: Clinical reasoning education in the clerkship years: A cross-disciplinary national needs assessment.

[This corrects the article DOI: 10.1371/journal.pone.0273250.].

Minding the gap: towards a shared clinical reasoning lexicon across the pre-clerkship/clerkship transition.

Teaching and learning of clinical reasoning are core principles of medical education. However, little guidance exists for faculty leaders to navigate curricular transitions between pre-clerkship and clerkship curricular phases. This study compares how educational leaders in these two phases understand clinical reasoning instruction. Previously reported cross-sectional surveys of pre-clerkship clinical skills course directors, and clerkship leaders were compared. Comparisons focused on perceived importance of a number of core clinical reasoning concepts, barriers to clinical reasoning instruction, level of familiarity across the undergraduate medical curriculum, and inclusion of clinical reasoning instruction in each area of the curriculum. Analyses were performed using the Mann Whitney U test. Both sets of leaders rated lack of curricular time as the largest barrier to teaching clinical reasoning. Clerkship leaders also noted a lack of faculty with skills to teach clinical reasoning concepts as a significant barrier (p < 0.02), while pre-clerkship leaders were more likely to perceive that these concepts were too advanced for their students (p < 0.001). Pre-clerkship leaders reported a higher level of familiarity with the clerkship curriculum than clerkship leaders reported of the pre-clerkship curriculum (p < 0.001). As faculty transition students from the pre-clerkship to the clerkship phase, a shared understanding of what is taught and when, accompanied by successful faculty development, may aid the development of longitudinal, milestone-based clinical reasoning instruction.

Single-Strand "Short Isometric Construct" Medial Collateral Ligament Reconstruction Restores Valgus and Rotational Stability While Isolated Deep MCL and Superficial MCL Reconstruction Do Not.

BACKGROUND: Historical MCL (medial collateral ligament) reconstruction (MCLR) techniques have focused on the superficial MCL (sMCL) to restore valgus stability while frequently ignoring the importance of the deep MCL (dMCL) in controlling tibial external rotation. The recent recognition of the medial ligament complex importance has multiple studies revisiting medial anatomy and questioning contemporary MCLR techniques. PURPOSE: To assess whether (1) an isolated sMCL reconstruction (sMCLR), (2) an isolated dMCL reconstruction (dMCLR), or (3) a novel single-strand short isometric construct (SIC) would restore translational and rotational stability to a knee with a dMCL and sMCL injury. STUDY DESIGN: Controlled laboratory study. METHODS: Biomechanical testing was performed on 14 fresh-frozen cadaveric knee specimens using a custom multiaxial knee activity simulator. The specimens were divided into 2 groups. The first group was tested in 4 states: intact, after sectioning the sMCL and dMCL, isolated sMCLR, and isolated dMCLR. The second group was tested in 3 states: intact, after sectioning the sMCL and dMCL, and after single-strand SIC reconstruction (SICR). In each state, 4 loading conditions were applied at 0°, 20°, 40°, 60°, and 90° of knee flexion: 8-N·m valgus torque, 5-N·m external rotation torque, 90-N anterior drawer, and combined 90-N anterior drawer plus 5-N·m tibial external rotation torque. Anterior translation, valgus rotation, and external rotation of the knee were measured for each state and loading condition using an optical motion capture system. RESULTS: sMCL and dMCL transection resulted in increased laxity for all loading conditions at all flexion angles. Isolated dMCLR restored external rotation stability to intact levels throughout all degrees of flexion, yet valgus stability was restored only at 0° of flexion. Isolated sMCLR restored valgus and external rotation stability at 0°, 20°, and 40° of flexion but not at 60° or 90° of flexion. Single-strand SICR restored valgus and external rotation stability at all flexion angles. In the combined anterior drawer plus external rotation test, isolated dMCL and single-strand SICR restored stability to the intact level at all flexion angles, while the isolated sMCL restored stability at 20° and 40° of flexion but not at 60° or 90° of flexion. CONCLUSION: In the cadaveric model, single-strand SICR restored valgus and rotational stability throughout the range of motion. dMCLR restored rotational stability to the knee throughout the range of motion but did not restore valgus stability. Isolated sMCLR restored external rotation and valgus stability in early flexion. CLINICAL RELEVANCE: In patients with anteromedial rotatory instability in the knee, neither an sMCLR nor a dMCLR is sufficient to restore stability.

Biomechanical evaluation of a new MatrixMandible plating system on cadaver mandibles.

PURPOSE: Current mandibular plating systems contain a wide range of plates and screws needed for the treatment of mandibular reconstruction and mandibular fractures. The authors' hypothesis was that a single diameter screw could be used in all applications in a plating system. Therefore, the purpose of this study was to test if the 2.0-mm locking screws could replace the 2.4-mm screws to stabilize a 2.5-mm-thick reconstruction plate in the treatment of mandibular discontinuity. MATERIALS AND METHODS: Thirty-six fresh human cadaveric mandibles were used: 18 were plated using 2.0-mm locking screws (experimental) and the other 18 were plated using 2.4-mm locking screws (control). Each group was further divided into 3 subgroups based on the site of loading application: the ipsilateral (right) second premolar region, the central incisal region, and the contralateral (left) first molar region. The same ipsilateral (right) mandibular angular discontinuity was created by the same surgeon. The mandible was mounted on a material testing machine. The micromotions between the 2 segments, permanent and elastic displacements, were recorded after incremental ramping loads. The magnitude of screw back-out and the separation between plate and bone were recorded using a laser scanner (resolution, 0.12 mm) before and after the loading applications. The data were processed. Descriptive analyses and a general linear model for repeated measures analysis of variance were performed. RESULTS: There was no statistically significant difference in permanent displacement (mean, 1.16 and 0.82 mm, respectively) between the 2.0-mm and 2.4-mm screw groups. There also was no statistically significant difference in elastic displacement between the 2 groups (mean, 1.48 and 1.21 mm, respectively). Finally, there were no statistically significant differences in screw back-out or separation between plate and bone between the 2 groups. All means for screw back-out and separation between screw and bone for each group were judged within the error of the laser scanning system (<0.12 mm). CONCLUSION: One may anticipate that the mechanical functions of the 2.0-mm locking screws are not different from those of the 2.4-mm screws when a 2.5-mm-thick reconstruction plate is used to reconstruct mandibular angular discontinuity. However, further biomechanical studies (ie, fatigue of screws) are warranted before a randomized clinical trial can be conducted to definitively prove that the 2.4-mm screws can be replaced by 2.0-mm screws.

Learning by doing and creation of the shared discovery curriculum.

BACKGROUND: The Michigan State College of Human Medicine began as an experiment to teach medical students in community-based settings and to create a primary care workforce for the state. Decades later, CHM faced internal and external challenges that spurred creation of a new curriculum - the Share Discovery Curriculum - founded on learning by doing and other learning theories. METHODS: A curricular design group (CDG) developed guiding principles for reform. Based on this, pedagogies and structures were selected to achieve this vision and developed into a curricular structure. Components of the first-year curriculum were piloted with a group of students and faculty members. RESULTS: Six guiding principles were endorsed, grounded in learning theories such as Dewey's Learning by Doing. Based upon these, several key features of the new curriculum emerged: learning communities; one-on-one coaches for students; symptom-based presentations for content; simulation, authentic clinical tasks, flipped classrooms, and modified practice-based learning as primary teaching modalities; early, integrated clinical and scientific learning; milestones as course learning objectives; and a multidimensional, competency-based assessment system. DISCUSSION: The process and outcomes described here are intended as an exemplar for schools undertaking curricular change. Early stakeholder engagement, faculty development, sustainable administrative systems, and managing complexity are core to the success of such endeavors.

Utilizing learning communities to deliver an integrated undergraduate medical education curriculum.

AIM: Learning communities (LCs) have been identified as a structure to support student wellness as well as create a positive learning environment and have been increasingly adopted in undergraduate medical education (UGME). In 2016, Michigan State University College of Human Medicine made curricular changes which integrated basic, social, and clinical sciences. One of the major strategies adopted to deliver this integrated curriculum was to create LCs that served as a central scaffold for students' academic development. Our primary aim is to describe how the school utilized LC faculty to deliver this core integrated curriculum. METHODS: Students were surveyed about their perceptions of the effectiveness of the LCs in delivering an integrated science curriculum. Student academic performance in the new curriculum was compared to that of students from the legacy curriculum as a measure of the effectiveness of the curricular changes. RESULTS: The percentage of students in each class who responded to surveys ranged between 78.7% and 95.8%. Mean Likert responses (1 = strongly disagree; 5 = strongly agree) for statements 'the Faculty Fellow is effective in helping me learn the scholar group content', 'the Faculty Fellow is an effective teacher in our scholar group', and 'the Faculty Fellow is well prepared for our scholar group' ranged from 4.37 to 4.78, 4.72 to 4.76, and 4.81 to 4.86, respectively. In addition, a comparison of summative exam scores of the new curriculum's students to the legacy curriculum's students demonstrated comparable or better performances in the new curriculum. CONCLUSIONS: Utilizing LCs to deliver an integrated science curriculum is an underutilized strategy in UGME. Surveys on student satisfaction and academic performance are encouraging. Additional outcome measures are planned to continually evaluate this innovative multifaceted integration.

An Exemplar Milestone Framework for Scaffolding a Competency-Based Medical School Curriculum.

A strong competency and milestone framework is imperative for medical schools adopting competency-based education and assessment. Milestones can be used to align what is taught and what students are asked to demonstrate from matriculation to graduation. We describe the creation and implementation of our milestone framework as an exemplar. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-022-01558-1.

Clinical reasoning education in the clerkship years: A cross-disciplinary national needs assessment.

BACKGROUND: Improving clinical reasoning education has been identified as an important strategy to reduce diagnostic error-an important cause of adverse patient outcomes. Clinical reasoning is fundamental to each specialty, yet the extent to which explicit instruction in clinical reasoning occurs across specialties in the clerkship years remains unclear. METHOD: The Alliance for Clinical Education (ACE) Clinical Reasoning Workgroup and the Directors of Clinical Skills Courses (DOCS) Clinical Reasoning Workgroup collaborated to develop a clinical reasoning needs assessment survey. The survey questionnaire covered seven common clinical reasoning topics including illness scripts, semantic qualifiers, cognitive biases and dual process theory. Questionnaires were delivered electronically through ACE member organizations, which are primarily composed of clerkship leaders across multiple specialties. Data was collected between March of 2019 and May of 2020. RESULTS: Questionnaires were completed by 305 respondents across the six organizations. For each of the seven clinical reasoning topics, the majority of clerkship leaders (range 77.4% to 96.8%) rated them as either moderately important or extremely important to cover during the clerkship curriculum. Despite this perceived importance, these topics were not consistently covered in respondents' clerkships (range 29.4% to 76.4%) and sometimes not covered anywhere in the clinical curriculum (range 5.1% to 22.9%). CONCLUSIONS: Clerkship educators across a range of clinical specialties view clinical reasoning instruction as important, however little curricular time is allocated to formally teach the various strategies. Faculty development and restructuring of curricular time may help address this potential gap.

Does acetabular retroversion affect range of motion after total hip arthroplasty?

BACKGROUND: Increasingly, acetabular retroversion is recognized in patients undergoing hip arthroplasty. Although prosthetic component positioning is not determined solely by native acetabular anatomy, acetabular retroversion presents a dilemma for component positioning if the surgeon implants the device in the anatomic position. QUESTIONS/PURPOSES: We asked (1) whether there is a difference in ROM between surface replacement arthroplasty (SRA) and THA in the retroverted acetabulum, and (2) does increased femoral anteversion improve ROM in the retroverted acetabulum? METHODS: Using a motion analysis tracking system, we determined the ROM of eight cadaveric hips and then created virtual CT-reconstructed bone models of each specimen. ROM was determined with THA and SRA systems virtually implanted with (1) the acetabular component placed in 45° abduction and matching the acetabular anteversion (average 23° ± 4°); (2) virtually retroverting the bony acetabulum 10°; and (3) after anteverting the THA femoral stem 10°. RESULTS: SRA resulted in ROM deficiencies in four of six maneuvers, averaging 25% to 29% in the normal and retroverted acetabular positions. THA restored ROM in all six positions in the normal acetabulum and in four of the six retroverted acetabula. The two deficient positions averaged 5% deficiency. THA with increased femoral stem anteversion restored ROM in five positions and showed only a 2% deficiency in the sixth position. Compared with the intact hip, ROM deficits were seen after SRA in the normal and retroverted acetabular positions and to a lesser extent for THA which can be improved with increased femoral stem anteversion. CONCLUSION: Poor ROM may result after SRA if acetabular retroversion is present.

Which procedure better restores intact hip range of motion: total hip arthroplasty or resurfacing? A combined cadaveric and computer simulation study.

Previous comparisons of hip range of motion (ROM) after THA and surface replacement arthroplasty (SRA) are inconclusive due to the lack of soft tissue considerations and dissimilar control groups. The normal ROMs of 8 intact cadaveric hips were determined by placing specimens in 6 discrete, predefined positions of rotation at a standard torque. In each position, the limiting factor of ROM, either bony impingement or soft tissue restriction, could be determined. Total hip arthroplasty and SRA components were virtually implanted, and ROM until impingement was determined. With a THA, the ROM was comparable to that of the intact hip. With an SRA, flexion (111° ± 13°) was less than for the intact hip (131° ± 6°). Surface replacement arthroplasty, but not THA, significantly decreases the ROM compared to intact hips.

A quasi-experimental evaluation of a breastfeeding support program for low income women in Michigan.

We examined the effectiveness of a peer counseling breastfeeding support program for low income women in Michigan who participate in WIC. Because there was more demand for services than could be met by the program, many women who requested services were not subsequently contacted by a peer counselor. We used a quasi-experimental methodology that utilized this excess demand for services to estimate the causal effect of the support program on several breastfeeding outcomes. We relied on data derived from administrative and survey-based sources. After providing affirmative evidence that our key assumption is consistent with the data, we estimated that the program caused the breastfeeding initiation to increase by about 27 percentage points and the mean duration of breastfeeding to increase by more than 3 weeks. The support program we evaluated was very effective at increasing breastfeeding among low income women who participate in WIC, a population that nationally breastfeeds at rates well below the national average and below what is recommended by public health professionals. Given the substantial evidence that breastfeeding is beneficial for both the child and mother, the peer counseling breastfeeding support program should be subjected to a cost/benefit analysis and evaluated at other locales.

Anatomic double-bundle anterior cruciate ligament reconstruction: kinematics and knee flexion angle-graft tension relation.

PURPOSE: The purpose of this study was to compare the bundle tension curves and resultant knee kinematics between 2 tensioning protocols in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Anatomic double-bundle ACL reconstruction was performed in 7 male cadaveric knees. Each graft was tensioned to 22 N under 2 conditions: (1) both bundles tensioned at 20 degrees of knee flexion (20/20 protocol) or (2) posterolateral (PL) bundle tensioned at 15 degrees and anteromedial (AM) bundle at 45 degrees (45/15 protocol). Knee kinematics were recorded in response to anterior and combined rotatory loads in the intact, ACL-deficient, and reconstructed states. Bundle tension was recorded dynamically with knee motion and during each loading test. RESULTS: Tensioning both bundles at 20 degrees of knee flexion resulted in a reciprocal bundle tension pattern that was not statistically different; the PL bundle tension was greater than the AM bundle tension in full extension, and the AM bundle tension was greater than the PL bundle tension from 25 degrees to 120 degrees. In the second tensioning protocol, the AM bundle tension was significantly greater than the PL bundle tension at all flexion angles. Both tensioning protocols restored normal knee kinematics. CONCLUSIONS: Bundle-tensioning protocol is a variable that has a significant effect on the bundle-loading patterns in double-bundle ACL reconstruction. The 20/20 protocol resulted in AM and PL bundle-loading patterns that were equivalent during dynamic testing, whereas the 45/15 protocol led to excessive tension in the AM bundle in full extension. We recommend equal tensioning of both bundles with the knee at 20 degrees of flexion to restore relatively normal tension curves in each bundle and to avoid excessive stress on the AM bundle. CLINICAL RELEVANCE: In double-bundle ACL reconstruction, there is no consensus regarding bundle-tensioning protocols. This study provides data on the individual bundle tension curves that result from 2 commonly used tensioning protocols. These data will assist clinicians as the technique and application of double-bundle ACL reconstruction move forward.