Time to Return to School After 10 Common Orthopaedic Surgeries Among Children and Adolescents.

BACKGROUND: Return to school among adolescents is often overlooked in orthopaedic outcome studies. The purpose was to measure the time missed from school after 10 common orthopedic surgeries. METHODS: Patients, 5 to 19 years old enrolled in elementary, middle, or high school, who underwent treatment for fixation of type III supracondylar humerus fracture, midshaft femur fracture fixation, isolated anterior cruciate ligament reconstruction, isolated partial menisectomy, adolescent idiopathic scoliosis fusion, closed reduction of both-bone forearm fracture, arthroscopic Bankart repair, hip arthroscopy with femoroacetabular impingement correction, limb length discrepancy correction, or surgical fixation of slipped capital femoral epiphysis during the 2014/2015 and 2015/2016 school years were identified for this Institutional Review Board-approved study. All patients were contacted after surgery to determine date of return to school, number of days in session, and number of school days missed. RESULTS: Two hundred six patients met the inclusion criteria for this study. Mean age at time of surgery was 13.0±3.8 years. There were 105 males (51%). Mean time to return to school overall was 13.0±15.2 days. Very few students (n=9; 4%) did not miss any school days during recovery from the procedure of interest. The average number of days missed from school for males was 6.6 days compared with 8.4 days in females (P=0.20). There was no difference between patients aged 5 to 12 years compared with those aged 13 to 19 years (7.1 vs. 7.7 d, respectively; P=0.69). On average, patients who underwent closed reduction of a both-bone forearm fracture returned to school the quickest following surgery (3.4±1.2 d) and missed the least amount of in-session school days (1.9±0.9 d), and those who underwent adolescent idiopathic scoliosis fusion were out of school the longest (42.3±21.4 d) and missed the greatest number of in-session school days (27.6±14.7 d). CONCLUSIONS: Information regarding average time missed from school for 10 common orthopaedic surgeries can be used by clinicians to counsel patients and their families regarding expected recovery time. LEVEL OF EVIDENCE: Level IV.

The anatomy of the infrarenal lumbar splanchnic nerves in human cadavers: implications for retroperitoneal nerve-sparing surgery.

Injury to the nerves of the aortic- and superior hypogastric plexuses during retroperitoneal surgery often results in significant post-operative complications, including retrograde ejaculation and/or loss of seminal emission in males. Although previous characterizations of these plexuses have done well to provide a basis for understanding the typical anatomy, additional research into the common variations of these plexuses could further optimize nerve-sparing techniques for retroperitoneal surgery. To achieve this, the present study aimed to document the prevalence and positional variability of the infrarenal lumbar splanchnic nerves (LSNs) through gross dissection of 26 human cadavers. In almost all cases, two LSNs were observed joining each side of the aortic plexus, with 48% (left) and 33% (right) of specimens also exhibiting a third joining inferior to the left renal vein. As expected, the position of the LSNs varied greatly between specimens. That said, the vast majority (98%) of LSNs joining the aortic plexus were found to originate from the lumbar sympathetic trunk above the level of the inferior mesenteric artery. It was also found that, within specimens, adjacent LSNs often coursed in parallel. In addition to these nerves, 85% of specimens also demonstrated retroaortic LSN(s) that were angled more inferior compared with the other LSNs (P < 0.05), and exhibited a unique course between the aorta/common iliac arteries and the left common iliac vein before joining the superior hypogastric plexus below the aortic bifurcation. These findings may have significant implications for surgeons attempting nerve-sparing procedures of the sympathetic nerves in the infrarenal retroperitoneum such as retroperitoneal lymphadenectomies. We anticipate that the collective findings of the current study will help improve such retroperitoneal nerve-sparing surgical procedures, which may assist in preserving male ejaculatory function post-operatively.

Ultrasound-guided lateral-medial transmuscular quadratus lumborum block for analgesia following anterior iliac crest bone graft harvesting: a clinical and anatomical study.

BACKGROUND: The anterior iliac crest (AIC) is one of the most common sites for harvesting autologous bone, but the associated postoperative pain can result in significant morbidity. Recently, the transmuscular quadratus lumborum block (TQL) has been described to anesthetize the thoraco-lumbar nerves. This study utilizes a combination of cadaveric models and clinical case studies to evaluate the dermatomal coverage and analgesic utility of TQL for AIC bone graft donor site analgesia. METHODS: Ten ultrasound-guided TQL injections were performed in five cadaver specimens using a lateral-to-medial transmuscular approach. Twenty mL of 0.5% methylcellulose was injected on each side after ultrasound confirmation of the needle tip ventral to the quadratus lumborum muscle (QLM). Cranio-caudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy and direct staining of the thoraco-lumbar nerves were recorded. Following the anatomical findings, continuous catheter TQL blocks were performed in four patients undergoing ankle surgery with autologous AIC bone graft. The dermatomal anesthesia and postoperative analgesic consumption were recorded. RESULTS: In the anatomical component of the study, 9/10 specimens showed a lateral spread anterior to the transversalis fascia and medially between the QLM and psoas major muscle. Direct staining of the branches of the T12, L1, and L2 nerves was noted ventral to the QLM, while variable staining of the T9-T11 nerves was seen laterally in the transversus abdominis plane and the transversalis fascia. The vertical spread of injectate anterior to the QLM was T12 to the iliac crest (n = 5/10) and L1 to the iliac crest (n = 4/10). In the four patients who received TQL, the T9-L2 dermatomal anesthesia correlated with the injectate spread seen in the cadavers and provided effective analgesia at the bone graft donor site. CONCLUSION: Ultrasound-guided TQL injections consistently cover the thoraco-lumbar innervation relevant to the AIC graft donor site. The injectate spread seen in anatomical dissections correlated with the dermatomal anesthesia clinically. The TQL has the potential to provide reliable analgesia for patients undergoing AIC bone graft harvesting.

Retroperitoneal Lymph Node Dissection: Anatomical and Technical Considerations from a Cadaveric Study.

PURPOSE: Metastatic testis cancer in the retroperitoneum presents a technical challenge to urologists in the primary and post-chemotherapy settings. Where possible, bilateral nerve sparing retroperitoneal lymph node dissection should be performed in an effort to preserve ejaculatory function. However, this is often difficult to achieve, given the complex neurovascular anatomy. We performed what is to our knowledge the first comprehensive examination of the anatomical relationships between the sympathetic nerves of the aortic plexus and the lumbar vessels to facilitate navigation and nerve sparing during bilateral retroperitoneal lymph node dissection. MATERIALS AND METHODS: The relative anatomy of the infrarenal vasculature (lumbar vessels, right gonadal vein and inferior mesenteric artery) was investigated in 21 embalmed human cadavers. The complex relationships between these vessels and the sympathetic nerves of the aortic plexus were examined by dissection of an additional 8 fresh human cadavers. RESULTS: Analysis of the infrarenal vasculature from 21 cadavers demonstrated that the position of the right gonadal vein and the inferior mesenteric artery may be useful to locate the right superior lumbar vein and the first pair of infrarenal lumbar arteries as well as the common lumbar trunk (vein) and the second pair of infrarenal lumbar arteries, respectively. Furthermore, the lumbar splanchnic nerves supplying the aortic plexus were most often positioned anteromedial to the respective lumbar vein. CONCLUSIONS: The current study describes the complex neurovascular relationships that are crucial to performing successful nerve sparing retroperitoneal lymph node dissection. Surgical techniques are also discussed. Collectively, these results may help surgeons decrease the rate of postoperative retrograde ejaculation and/or anejaculation.

Histological verification of the prehypogastric and ovarian ganglia confirms a bilaterally symmetrical organization of the ganglia comprising the aortic plexus in female human cadavers.

The aortic plexus is a network of sympathetic nerves positioned along the infrarenal abdominal aorta. Recently, we characterized the aortic plexus and its ganglia (inferior mesenteric, left/right spermatic, and prehypogastric ganglion) in males; however, the literature minimally describes its anatomy in females. In the present study, we conducted the first histological examination of the left and right ovarian ganglia, while also investigating whether females, like males, exhibit a prehypogastric ganglion. The ganglia were dissected from embalmed (n = 32) and fresh (n = 1) human cadavers, and H&E staining was used to confirm the presence of a left ovarian ganglion in 31/31 specimens, a right ovarian ganglion in 29/29 specimens and a prehypogastric ganglion in 25/28 specimens. Comparable to the topographic arrangement in males, there is a bilateral organization of the ganglia comprising the aortic plexus in females. More specifically, the left and right ovarian ganglia were positioned in close relation to their respective ovarian artery, whereas the prehypogastric ganglion was positioned within the right cord of the aortic plexus, contralateral to the inferior mesenteric ganglion. Using immunohistochemistry, it was shown that all ganglia from the fresh cadaver stained positive for tyrosine hydroxylase, thereby confirming their sympathetic nature. Having provided the first topographical and histological characterization of the ovarian and prehypogastric ganglia in females, future studies should seek to determine their specific function.

A Three-dimensional Analysis of Zygomatic Symmetry in Normal, Uninjured Faces.

Current approaches to facial reconstruction are based on the assumption of facial symmetry, though this has yet to be established in the literature. Through quantitative and qualitative analysis, symmetry of normal, male faces is examined here using the zygomatic complex as a bellwether for the rest of the facial skeleton. Three-dimensional models reconstructed from the computed tomography scans of 30 adult male patients displaying normal facial skeletal anatomy were analyzed. Seven zygomatic landmarks were identified on all craniofacial models, and asymmetry scores were calculated based on the average deviation distance upon reflection of 1 hemiface across the midfacial plane. Deviation maps were then generated for each zygomatic pair to enable visualization of the asymmetry. All landmarks displayed a slight (<3 mm) deviation from perfect symmetry, and analysis of zygomatic form asymmetry revealed an average of 0.4 mm of surface deviation between hemifaces. The presence of such slight asymmetries in the zygoma warrants further investigation as to the clinical relevance of such skeletal asymmetries from both an esthetic and biomechanical consideration to provide insight as to the proper approach to zygomatic restoration in cases of zygomatic fracture.

Anatomy of the nerves and ganglia of the aortic plexus in males.

It is well accepted that the aortic plexus is a network of pre- and post-ganglionic nerves overlying the abdominal aorta, which is primarily involved with the sympathetic innervation to the mesenteric, pelvic and urogenital organs. Because a comprehensive anatomical description of the aortic plexus and its connections with adjacent plexuses are lacking, these delicate structures are prone to unintended damage during abdominal surgeries. Through dissection of fresh, frozen human cadavers (n = 7), the present study aimed to provide the first complete mapping of the nerves and ganglia of the aortic plexus in males. Using standard histochemical procedures, ganglia of the aortic plexus were verified through microscopic analysis using haematoxylin & eosin (H&E) and anti-tyrosine hydroxylase stains. All specimens exhibited four distinct sympathetic ganglia within the aortic plexus: the right and left spermatic ganglia, the inferior mesenteric ganglion and one previously unidentified ganglion, which has been named the prehypogastric ganglion by the authors. The spermatic ganglia were consistently supplied by the L1 lumbar splanchnic nerves and the inferior mesenteric ganglion and the newly characterized prehypogastric ganglion were supplied by the left and right L2 lumbar splanchnic nerves, respectively. Additionally, our examination revealed the aortic plexus does have potential for variation, primarily in the possibility of exhibiting accessory splanchnic nerves. Clinically, our results could have significant implications for preserving fertility in men as well as sympathetic function to the hindgut and pelvis during retroperitoneal surgeries.

Anatomy of the proximal tibiofibular joint and interosseous membrane, and their contributions to joint kinematics in below-knee amputations.

A result of below-knee amputations (BKAs) is abnormal motion that occurs about the proximal tibiofibular joint (PTFJ). While it is known that joint morphology may play a role in joint kinematics, this is not well understood with respect to the PTFJ. Therefore, the purposes of this study were: (i) to characterize the anatomy of the PTFJ and statistically analyze the relationships within the joint; and (ii) to determine the relationships between the PTFJ characteristics and the degree of movement of the fibula in BKAs. The PTFJ was characterized in 40 embalmed specimens disarticulated at the knee, and amputated through the mid-tibia and fibula. Four metrics were measured: inclination angle (angle at which the fibula articulates with the tibia); tibial and fibular articular surface areas; articular surface concavity and shape. The specimens were mechanically tested by applying a load through the biceps femoris tendon, and the degree of motion about the tibiofibular joint was measured. Regression analyses were performed to determine the relationships between the different PTFJ characteristics and the magnitude of fibular abduction. Finally, Pearson correlation analyses were performed on inclination angle and surface area vs. fibular kinematics. The inclination angle measured on the fibula was significantly greater than that measured on the tibia. This difference may be attributed to differences in concavity of the tibial and fibular surfaces. Surface area measured on the tibia and fibula was not statistically different. The inclination angle was not statistically correlated to surface area. However, when correlating fibular kinematics in BKAs, inclination angle was positively correlated to the degree of fibular abduction, whereas surface area was negatively correlated. The characteristics of the PTFJ dictate the amount of fibular movement, specifically, fibular abduction in BKAs. Predicting BKA complications based on PTFJ characteristics can lead to recommendations in treatment.

A cadaveric study of the anterolateral ligament: re-introducing the lateral capsular ligament.

PURPOSE: The purpose of this study was to verify and characterize the anatomical properties of the anterolateral capsule, with the aim of establishing a more accurate anatomical description of the anterolateral ligament (ALL). Furthermore, microscopic analysis of the tissue was performed to determine whether the ALL can morphologically be classified as ligamentous tissue, as well as reveal any potential functional characteristics. METHODS: Three different modalities were used to validate the existence of the ALL: magnetic resonance imagining (MRI), anatomical dissection, and histological analysis. Ten fresh-frozen cadaveric knee specimens underwent MRI, followed by anatomical dissection which allowed comparison of MRI to gross anatomy. Nine additional fresh-frozen cadaveric knees (19 total) were dissected for a further anatomical description. Four specimens underwent H&E staining to look at morphological characteristics, and one specimen was analysed using immunohistochemistry to locate peripheral nervous innervation. RESULTS: The ALL was found in all ten knees undergoing MRI and all nineteen knees undergoing anatomical dissection, with MRI being able to predict its corresponding anatomical dissection. The ALL was found to have bone-to-bone attachment points from the lateral femoral epicondyle to the lateral tibia, in addition to a prominent meniscal attachment. Histological sectioning showed ALL morphology to be characteristic of ligamentous tissue, having dense, regularly organized collagenous bundles. Immunohistochemistry revealed a large network of peripheral nervous innervation, indicating a potential proprioceptive role. CONCLUSION: From this study, the ALL is an independent structure in the anterolateral compartment of the knee and may serve a proprioceptive role in knee mechanics.

Regional Variations in Cartilage Thickness of the Radial Head: Implications for Prosthesis Design.

PURPOSE: To characterize the regional variations in cartilage thickness around the radial head. METHODS: We dissected 27 cadaveric radii and scanned them with computed tomography in neutral position. Three-dimensional cartilage and subchondral bone surface models were generated from computed tomography scans and 2 independent observers processed them through a computer program to obtain cartilage thickness measurements. These measurements were taken at 41 predetermined landmarks around the periphery of the radial head and within the articular dish. RESULTS: At the periphery of the radial head, cartilage was thickest in the posteromedial region. Thickness values within the articular dish were similar but increased toward the rim. Regional variations within the rim (range, 0.76-1.73 mm) were also detected with the thickest region located anteriorly and thinnest region laterally. In addition, cartilage was significantly thicker in male relative to female specimens. CONCLUSIONS: Regional variations in cartilage thickness are present around the periphery and rim and within the articular dish of the radial head. CLINICAL RELEVANCE: Cartilage thickness across the articular dish may contribute to dish depth and the radius of curvature. This may be clinically important for the design of anatomic implants, because accounting for such subtle contours could help to restore radiocapitellar concavity-compression stability better.

ANATOMICAL VARIATIONS OF THE GREATER PALATINE NERVE IN THE GREATER PALATINE CANAL.

The greater palatine nerve and the greater palatine canal are common sites for maxillary anesthesia during dental and maxillo-facial procedures. The greater palatine nerve is thought to course as a single trunk through the greater palatine canal, branching after its exit from the greater palatine foramen. We describe intra-canalicular branching variations of the greater palatine nerve found in 8 of 20 embalmed dissection specimens. Such variation is previously unreported in the literature. We characterize the variations in branching pattern and discuss the possible implications for clinical practice.

The lumbar arteries and veins: Quantification of variable anatomical positioning with application to retroperitoneal surgery.

The lumbar arteries and veins are segmentally arranged vessels in the abdomen that supply the vertebrae and posterior abdominal/paravertebral muscles. Recent studies have indicated that these vessels have a tendency to vary from the classical description of bilateral pairing. The objective of this study was to more accurately characterize the anatomy of the lumbar vessels through the dissection of 22 cadaveric specimens and examination of 41 patients' computed tomography angiography scans. The positions of the lumbar vessels were measured in reference to the bifurcation/confluence of the common iliac arteries/veins. In 22 cadaveric specimens, the course of the lumbar veins was dissected to the psoas major muscle to characterize venous tributaries. Our results indicate that the lumbar veins were rarely paired, segmentally diverged closer to the iliocaval confluence, and preferentially drained into the left side of the IVC. Several types of lumbar veins were additionally characterized based on their consistent coursing patterns. In contrast, the lumbar arteries exhibited pairing, and these successive pairs were found to be equally spaced along the length of the infrarenal abdominal aorta. In specimens where the median sacral artery and 4th lumbar artery pair arose from a trifurcating common trunk, the positions of the 3rd and 4th lumbar arteries were significantly inferior (P < 0.05) compared to those with independent median sacral arteries. Clinically, proper management of the anatomical patterns described in this study may be pivotal in reducing the incidence of intraoperative damage to the lumbar vessels, and may help in the treatment of vascular diseases.

Ultrasound-guided greater palatine nerve block: a case series of anatomical descriptions and clinical evaluations.

BACKGROUND: Greater palatine nerve (GPN) block is commonly performed for maxillary and palatal anesthesia by using bony landmarks. Ultrasound (US) can be used to consistently identify greater palatine foramen (GPF) as a defect in the bony palate enabling US-guided injections near the foramen. METHODS: We scanned and injected 16 undissected well-embalmed hemisectioned cadaveric heads after excluding major anatomical malformations. A linear high-frequency hockey stick probe (7-13 MHz) positioned in long axis to the hard palate visualized GPF as a discontinuity in the hard palate. US-guided injections of 0.1 mL India ink were made in an oblique plane. Specimens were dissected immediately after injection, and dye distribution was noted. The success rate of identification of GPF, number of attempts, and number of successful injections were recorded. The technique was evaluated clinically in 7 patients undergoing dental procedures. Five patients had US-guided injections, and 2 patients received US-assisted greater palatine canal blocks. RESULTS: GPF was successfully identified in 16 hemisectioned heads (n = 16). In 7 of 16 hemisectioned cadaveric specimens (n = 7/16), needle pass was seen on the US and traces of India ink were found within the greater palatine canal and pterygopalatine fossa. In the remaining heads (n = 9/16), the dye was observed in the mucosal tissue of the hard palate anterior to the GPF or in the soft palate. Clinical evaluation reconfirmed successful identification of GPF by US in 6 of 7 patients (n = 6/7). US-guided injections were successful in 6 of the 8 attempted blocks (n = 6/8) with median number (range) of attempts being 2 (1-4). US-assisted injections were successful in 2 patients (n = 2/2). CONCLUSIONS: US has the potential to successfully locate and characterize GPF in normal and edentulous maxilla. US-guided GPN blocks can be technically challenging. The clinical applicability of US guidance or assistance for GPN block needs further evaluation in a larger sample of patients.

Evaluating the impact of an integrated multidisciplinary head & neck competency-based anatomy & radiology teaching approach in radiation oncology: a prospective cohort study.

BACKGROUND: Modern radiation oncology demands a thorough understanding of gross and cross-sectional anatomy for diagnostic and therapeutic applications. Complex anatomic sites present challenges for learners and are not well-addressed in traditional postgraduate curricula. A multidisciplinary team (MDT) based head-and-neck gross and radiologic anatomy program for radiation oncology trainees was developed, piloted, and empirically assessed for efficacy and learning outcomes. METHODS: Four site-specific MDT head-and-neck seminars were implemented, each involving a MDT delivering didactic and case-based instruction, supplemented by cadaveric presentations. There was no dedicated contouring instruction. Pre- and post-testing were performed to assess knowledge, and ability to apply knowledge to the clinical setting as defined by accuracy of contouring. Paired analyses of knowledge pretests and posttests were performed by Wilcoxon matched-pair signed-rank test. RESULTS: Fifteen post-graduate trainees participated. A statistically significant (p < 0.001) mean absolute improvement of 4.6 points (17.03%) was observed between knowledge pretest and posttest scores. Contouring accuracy was analyzed quantitatively by comparing spatial overlap of participants' pretest and posttest contours with a gold standard through the dice similarity coefficient. A statistically significant improvement in contouring accuracy was observed for 3 out of 20 anatomical structures. Qualitative and quantitative feedback revealed that participants were more confident at contouring and were enthusiastic towards the seminars. CONCLUSIONS: MDT seminars were associated with improved knowledge scores and resident satisfaction; however, increased gross and cross-sectional anatomic knowledge did not translate into improvements in contouring accuracy. Further research should evaluate the impact of hands-on contouring sessions in addition to dedicated instructional sessions to develop competencies.

Surgically relevant aortic arch mapping using computed tomography.

BACKGROUND: Recent advances in surgical repair of aortic arch pathologies have increasingly used endovascular stent-graft technology. The purpose of this study was to map the aortic arch diameters, branch orientations, and center line distances using a commercially available three-dimensional computed tomography-based software package and to propose a prototype design. METHODS: TeraRecon 3D imaging software was used for morphological assessment of computed tomography scans from 45 patients (mean age: 68 years; 26 males, 19 females). In each patient, 13 measurements were made in relation to the center line, including diameters at several preset points, distances, and branch vessel orientations. RESULTS: The mode of the proximal diameters (2 cm and 4 cm distal to coronary artery) was 32 mm and 34 mm. The mode of the distance between the innominate and left common carotid arteries was 5 mm and 6 mm, and the mode of the distance between the left common carotid artery and left subclavian artery was 8 mm. Most commonly, the left common carotid artery was anterior to the other arch branches by 3 to 5 mm. CONCLUSIONS: These anatomic measurements provide useful information for the advancement of minimally invasive and safer surgical repair of the aortic arch. Based on the most commonly observed measurements, a standardized off-the-shelf stent-graft is proposed that would be appropriate for the majority of patients.

An anatomic study of coronoid cartilage thickness with special reference to fractures.

BACKGROUND: Current coronoid fracture classification systems are based on fragment size and configuration using plain radiographs and/or computed tomography (CT). During surgery, coronoid fracture fragments appear much larger than anticipated because cartilage is radiolucent and therefore not accounted for with preoperative imaging. The purpose of this imaging study was to quantify the articular cartilage thickness of the coronoid, with reference to coronoid fractures. MATERIALS AND METHODS: Twenty-four cadaveric ulnae were dissected, imaged with CT, and analyzed by use of image analysis software. Thirteen identifiable landmarks were chosen on the coronoid, olecranon, and proximal radioulnar joint to measure articular cartilage thickness. Intraobserver reliability and interobserver reliability were determined. RESULTS: Cartilage thickness was highest at the coronoid tip, with a mean of 3.0 mm (range, 1.7-4.6 mm). Cartilage thickness at the tip correlated inversely with age (P < .01) and correlated strongly with overall ulnar height and ulnar length (P < .05). All measurements had excellent intraobserver and interobserver reliability. CONCLUSION: The thickness of cartilage on the coronoid tip is not inconsequential. The results of this study indicate that a 2-mm coronoid tip fracture on CT scan may actually appear to be a mean of 5 mm thick when viewed at the time of surgery. Clinically, this is important because it may alter the classification, the decision to treat, or the type of fixation used. Importantly, biomechanical cadaveric studies assessing coronoid injuries have incorporated cartilage thickness into coronoid size measurements when creating simulated fractures; therefore, it is critical that the conclusions of such biomechanical studies be scrutinized with regard to their clinical recommendations. Surgeons should be aware of these discrepancies.

Are Clerks Proficient in the Basic Sciences? Assessment of Third-Year Medical Students' Basic Science Knowledge Prior to and at the Completion of Core Clerkship Rotations.

Basic sciences are a cornerstone of undergraduate medical education (UME), yet research indicates that students' basic science knowledge is not well retained. Many UME curricula are increasing the integration between the basic and clinical sciences with the goal of enhancing students' knowledge levels; however, the impact of clerkship training on students' basic science knowledge remains inconclusive. Thus, using clerkship directors' expectations as framework, we aimed to assess third-year medical students' basic science knowledge during clerkship training and evaluate the influence of clerkship training on their basic science knowledge. Using concepts deemed necessary by clerkship directors, we created a basic science assessment for each clerkship rotation. Assessments were distributed to third-year medical students as a pre- and post-test to assess their basic science knowledge prior to and at the completion of each rotation. On average, students retained ≥ 60% of relevant basic science knowledge from pre-clerkship, and neither clerkship rotation order, nor the basic science discipline being assessed, impacted students' basic science knowledge levels. Post-test data revealed that students, on average, reinforced fundamental concepts during clerkship. Interestingly, even though lower-performing students demonstrated the greatest post-test improvement, they still left each rotation with knowledge deficits compared with their highest-performing peers, suggesting that the clinical experience of clerkship appears to be particularly beneficial for lower-performing students, in regard to enhancing their basic science knowledge. Overall, results indicate that earlier exposure to clinical learning in UME, along with integration of basic science education into clerkship, could promote students' basic science knowledge acquisition and retention.

Correction to: Are Clerks Proficient in the Basic Sciences? Assessment of Third-Year Medical Students' Basic Science Knowledge Prior to and at the Completion of Core Clerkship Rotations.

[This corrects the article DOI: 10.1007/s40670-021-01249-3.].

Lateral subvastus approach: A cadaveric examination of its potential for total knee arthroplasty.

BACKGROUND: Lateral approaches to total knee arthroplasty (TKA) provide good surgical exposure and may provide greater ease of soft tissue balancing in patients with a valgus deformity; however, little is known about the versatility in non-valgus knees. The present study evaluated if a lateral subvastus approach can achieve adequate surgical exposure while maintaining less soft tissue damage compared with the medial parapatellar approach in knees without any significant deformity. METHODS: Using paired fresh-frozen cadaveric knees, the present study provides the first specimen-matched, side-by-side comparison of the lateral subvastus approach to the standard medial parapatellar approach to TKA. Ten knees were selected to undergo a lateral subvastus approach; the contralateral knee had a medial parapatellar approach as control. Incision length, surgical exposure and iatrogenic soft tissue damage were compared between the two approaches. RESULTS: The lateral subvastus approach was successfully performed using an incision length that was not different from that used in the medial parapatellar approach (p > 0.05). The resultant surgical exposure was comparable between approaches (p > 0.05). The risk of the approach included tearing of the vastus lateralis fibers, and/or abrasion of the iliotibial tract/patellar ligament. CONCLUSIONS: The lateral subvastus approach to TKA provided a comparable method to the standard medial parapatellar approach. Despite adequate exposure, the approach did risk soft tissue injury. Caution needs to be exercised to reduce the risk of iatrogenic injury to the vastus lateralis and surrounding ligaments. The successful implementation in this cadaveric study substantiates the need for further consideration of this approach in clinical practice.

Expectations and Perceptions of Students' Basic Science Knowledge: Through the Lens of Clerkship Directors.

Basic sciences are a cornerstone of undergraduate medical education (UME) as they provide a necessary foundation for the clinical sciences to be built upon and help foster trainees' competency. However, research indicates that students' basic science knowledge is not well retained, and as a result, students are ill-prepared, with respect to their basic science knowledge, when entering clerkship. One potential reason why students may not be prepared for clerkship is a lack of understanding as to which basic science concepts are critical for medical students to retain from pre-clerkship. We facilitated interviews with all core UME clerkship directors to establish which basic science concepts they expect students to know prior to each clerkship rotation, along with student's basic science strengths and areas of improvement. Interviews revealed that students are expected to have some knowledge of every basic science prior to clerkship, with pharmacology being a strong focus, as many specialties deal with common drugs and classes of drugs. Additionally, general anatomy and physiology knowledge were deemed student strengths in two rotations. Clerkship directors focused on perceived areas of improvement more than perceived strengths, with the most prevalent areas being pharmacology, microbiology, and detailed anatomy. These results represent views of clerkship directors from one Canadian institution; however, since clerks rotate through institutions across Canada, this data provides the impetus for creating a national discussion to help foster standardization of UME curricula, with the overarching goal of ensuring all graduates are proficient in the necessary fundamentals as they transition into residency.