Histological Structure of the Medial and Lateral Patellofemoral Ligaments and Implications for Reconstructive Surgery and Anterior Knee Pain.

Biomechanically, the patellofemoral joint is one of the most complex human articulations and a common source of pain for active adults and adolescents, particularly females.1-4 Patellofemoral disorders account for 20%-40% of all knee problems seen in family practice, sports medicine, and orthopedic clinics.1, 3-5.

Selection on Phalanx Development in the Evolution of the Bird Wing.

The frameshift hypothesis is a widely accepted model of bird wing evolution. This hypothesis postulates a shift in positional values, or molecular-developmental identity, that caused a change in digit phenotype. The hypothesis synthesized developmental and paleontological data on wing digit homology. The "most anterior digit" (MAD) hypothesis presents an alternative view based on changes in transcriptional regulation in the limb. The molecular evidence for both hypotheses is that the MAD expresses Hoxd13 but not Hoxd11 and Hoxd12. This digit I "signature" is thought to characterize all amniotes. Here, we studied Hoxd expression patterns in a phylogenetic sample of 18 amniotes. Instead of a conserved molecular signature in digit I, we find wide variation of Hoxd11, Hoxd12, and Hoxd13 expression in digit I. Patterns of apoptosis, and Sox9 expression, a marker of the phalanx-forming region, suggest that phalanges were lost from wing digit IV because of early arrest of the phalanx-forming region followed by cell death. Finally, we show that multiple amniote lineages lost phalanges with no frameshift. Our findings suggest that the bird wing evolved by targeted loss of phalanges under selection. Consistent with our view, some recent phylogenies based on dinosaur fossils eliminate the need to postulate a frameshift in the first place. We suggest that the phenotype of the Archaeopteryx lithographica wing is also consistent with phalanx loss. More broadly, our results support a gradualist model of evolution based on tinkering with developmental gene expression.

Use of the Contralateral Knee as a Control in the Destabilization of Medial Meniscus Osteoarthritis Rat Model.

Destabilization of the medial meniscus (DMM) induces osteoarthritis (OA) in a rat model, but using the contralateral limb as control is unknown. We examined DMM and obesity in an OA rat model using contralateral limbs as control. Femoral condyles and tibial plateaus were evaluated. No differences were found between knees across diet groups (P=.61) or between surgery scores in diet groups (both P>.49). Thus, contralateral limbs may be a control for short-term (≤4 weeks) studies.

Anatomical and Radiographic Characterization of the Lateral Patellofemoral Ligament of the Knee.

The purpose of the current study was to describe the femoral and patellar insertions of the lateral patellofemoral ligament (LPFL) and to determine their location relative to known anatomic and radiographic landmarks. In this descriptive laboratory study, 10 cadaveric knees were dissected, and the patellar and femoral insertions of the LPFL were identified. Each specimen was examined radiographically. The average center of the femoral insertion of the LPFL was calculated in reference to radiographic landmarks.

Fibrocartilaginous metaplasia and neovascularization of the anterior cruciate ligament in patients with osteoarthritis.

INTRODUCTION: The anterior cruciate ligament (ACL) prevents the anterior translocation and medial rotation of the tibia against the femur. It is typically composed of dense regular connective tissue (DRCT), small amount of loose connective tissue, little vasculature, and few nerve endings. The objective of the current study was to evaluate the details of histological changes in ACLs of patients with clinically diagnosed osteoarthritis (OA). MATERIALS AND METHODS: The ACLs of six patients undergoing total knee replacement because of OA (OA group) were compared with 16 normal ACLs from cadavers (control). The ACLs were analyzed for tissue composition and number of blood vessels across the full length and thickness of the ligament. Percentages for areas of DRCT, fibrocartilage, degenerative tissue, and vasculature were calculated. Tissue composition and relative number of blood vessels were compared between groups. RESULTS: The proportion of DRCT to non-DRCT was significantly smaller in the OA group than the control group (p < .001); non-DRCT included degenerative connective tissue and fibrocartilage. The number of blood vessels to area was greater in the OA group than the control group (p = .002). Six of control (37.5%) and five of OA ACLs (83%) showed areas of calcification. CONCLUSIONS: These results indicate that inflammatory processes contributing to OA in the knee cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, calcification, and formation of fibrocartilage-like tissue inside the ligament. These changes make ligament-retaining total knee arthroplasty a less beneficial option for knee repair.

Integration of Ultrasonography into the Undergraduate Medical Curriculum: Seven Years of Experience.

Ultrasound education has been part of the curriculum at A.T. Still University's Kirksville College of Osteopathic Medicine for over seven years (since 2011), and has been successfully integrated into the first two years of the four-year medical school curriculum. Students master ultrasound techniques through hands-on laboratories covering all body regions and systems. Ultrasound training has the potential to enhance the medical school learning experience for students and improve the quality of their future patient care.

Introduction of a Combined Gastrointestinal Histopathology Laboratory Exercise into an Undergraduate Medical School Curriculum.

To improve training in histology and pathology, an integrative, case-based histopathology laboratory exercise that used virtual microscopy was offered to first-year medical students during the KCOM gastrointestinal block. Students showed improvement in their understanding of histology and pathology after completing the exercise. Most students agreed that the combined histopathology laboratory helped them improve their understanding of histology and pathology in the gastrointestinal system and link normal histological and pathological changes to better understand disease processes.

Gross Anatomy Education Today: The Integration of Traditional and Innovative Methodologies.

The current study surveyed first-year osteopathic medical students about dissection, multimedia dissector, split laboratories, VH (virtual human) dissector, ultrasonography, and prior experience of anatomical concepts. Students perceived cadaveric dissection, multimedia dissector, and ultrasonography laboratories as important contributors for learning anatomy. Students felt cadaveric dissection was an important factor in their medical school selection. Study results suggested students perceived integrated anatomy courses that utilized dissection and multimodal approaches to deliver anatomical information as highly effective.

The role of excessive body weight and meniscal instability in the progression of osteoarthritis in a rat model.

BACKGROUND: The main objective of the study was to determine if excessive body weight and meniscal destabilization cause knee articular cartilage damage and changes in meniscal histology indicative of knee osteoarthritis (OA). METHODS: Forty female Lewis rats were randomly assigned to regular diet sham surgery, regular diet medial meniscus destabilization (DMM) surgery, high-fat diet sham surgery, or high-fat diet DMM surgery. Surgical intervention occurred four weeks after diet initiation. Rats were sacrificed four weeks post-surgery. Progression of OA was evaluated in femoral condyles and tibial plateaus using the Osteoarthritis Research Society International (OARSI) scoring system by two blinded scorers. Ossification of menisci was evaluated with digitized histological slides using a grid. RESULTS: DMM surgery had greater OARSI scores than sham surgery for all knee surfaces in both diet groups (all P < 0.004). The high-fat diet sham surgery group had greater OARSI scores than the regular diet sham surgery group on all knee surfaces (all P < 0.02). Histological evaluation showed the lateral meniscus had more bone than the medial meniscus, but there was no relationship between diet or surgery groups and amount of bone in the meniscus. CONCLUSIONS: Results suggested excessive body weight may contribute to spontaneous onset of OA and emphasized the importance of preventative care in those at risk of developing OA.

Histological characteristics of knee menisci in patients with osteoarthritis.

Existing data indicate knee menisci in patients with osteoarthritis (OA) show tearing, maceration, and fragmentation, but little is known about the change in histological structure. The aim of this study was to evaluate the change in the menisci histological structure in patients with clinically diagnosed knee OA. Fourteen patients undergoing surgical treatment of knee OA (OA group) and 14 cadaveric knees (control group) were assessed. Demographic data, medical history, synovial fluid, OA severity, medial meniscus (MM) tissue, and lateral meniscus (LM) tissue were collected from the OA group. Three nonconsecutive 10 µm cross-sectional tissue slices of menisci were analyzed for percentage of tissue calcification. Exact Mann-Whitney tests and Spearman correlation coefficients tested for relationships between variables. The major change in the histological structure of the menisci in patients with OA was calcification of the matrix, which was significantly greater in the OA group compared with the control group for MM (OA: 11.9%, cadaver: 5.17%; P < 0.001) and LM tissues (OA: 11.1%, cadaver: 4.2%; P < 0.001). A correlation between percent calcification of the MM and LM tissues existed in the OA group (ρ = 0.56, P = 0.04) but not the control group (P = 0.20). The most pronounced pathological change in the histology of menisci was calcification of the cartilage matrix, significantly greater in the OA group than the control group. A strong correlation between percent calcification of MM and LM tissues in patients with OA indicates changes in fibrocartilage matrix of menisci progress similarly in the medial and lateral compartments of the knee. Clin. Anat. 30:805-810, 2017. © 2017Wiley Periodicals, Inc.

Premedical anatomy experience and student performance in medical gross anatomy.

Gross anatomy is considered one of the most important basic science courses in medical education, yet few medical schools require its completion prior to matriculation. The effect of taking anatomy courses before entering medical school on performance in medical gross anatomy has been previously studied with inconsistent results. The effect of premedical anatomy coursework on performance in medical gross anatomy, overall medical school grade point average (GPA), and Comprehensive Osteopathic Medical Licensing Examination Level 1 (COMLEX 1) score was evaluated in 456 first-year osteopathic medical students along with a survey on its perceived benefits on success in medical gross anatomy course. No significant differences were found in gross anatomy grade, GPA, or COMLEX 1 score between students with premedical anatomy coursework and those without. However, significant differences and higher scores were observed in students who had taken three or more undergraduate anatomy courses including at least one with cadaveric laboratory. There was significantly lower perceived benefit for academic success in the medical gross anatomy course (P<.001) from those students who had taken premedical anatomy courses (5.9 of 10) compared with those who had not (8.2 of 10). Results suggest that requiring any anatomy course as a prerequisite for medical school would not have significant effect on student performance in the medical gross anatomy course. However, requiring more specific anatomy coursework including taking three or more undergraduate anatomy courses, one with cadaveric laboratory component, may result in higher medical gross anatomy grades, medical school GPA, and COMLEX 1 scores. Clin. Anat. 30:303-311, 2017. © 2017 Wiley Periodicals, Inc.

Distribution of Neuron Cell Bodies in the Intraspinal Portion of the Spinal Accessory Nerve in Humans.

The spinal accessory nerve is often identified as a purely motor nerve innervating the trapezius and sternocleidomastoid muscles. Although it may contain proprioceptive neurons found in cervical spinal levels C2-C4, limited research has focused on the histology of the spinal accessory nerve. The objective of the present study was to examine the spinal accessory nerve to determine if there are neuronal cell bodies within the spinal accessory nerve in humans. Cervical spinal cords were dissected from eight cadavers that had previously been used for dissection in other body regions. The segmental rootlets were removed to quantify the neuron cell bodies present at each spinal level. Samples were embedded in paraffin; sectioned; stained with hematoxylin and eosin; and examined using a microscope at 4×, 10×, and 40× magnification. Digital photography was used to image the samples. Neuronal cell bodies were found in 100% of the specimens examined, with non-grossly visible ganglia found at spinal levels C1-C4. The C1 spinal level of the spinal accessory nerve had the highest number of neuron cell bodies.

Impact of the clinical ultrasound elective course on retention of anatomical knowledge by second-year medical students in preparation for board exams.

Ultrasound has been integrated into a gross anatomy course taught during the first year at an osteopathic medical school. A clinical ultrasound elective course was developed to continue ultrasound training during the second year of medical school. The purpose of this study was to evaluate the impact of this elective course on the understanding of normal anatomy by second-year students. An anatomy exam was administered to students enrolled in the clinical ultrasound elective course before the start of the course and after its conclusion. Wilcoxon signed ranks tests were used to determine whether exam scores changed from the pre-test to the post-test. Scores from two classes of second-year students were analyzed. Students who took the elective course showed significant improvement in the overall anatomy exam score between the pre-test and post-test (P < 0.001). Scores for exam questions pertaining to the heart, abdomen, upper extremity, and lower extremity also significantly improved from the pretest to post-test (P < 0.001), but scores for the neck and eye showed no significant improvement. The clinical ultrasound elective course offered during the second year of medical school provided students with an important review of key anatomical concepts while preparing them for board exams. Our results suggested that more emphasis should be placed on head and neck ultrasound to improve student performance in those areas. Musculoskeletal, abdominal, and heart ultrasound labs were more successful for retaining relevant anatomical information.

Circumventing the polydactyly 'constraint': the mole's 'thumb'.

Talpid moles across all northern continents exhibit a remarkably large, sickle-like radial sesamoid bone anterior to their five digits, always coupled with a smaller tibial sesamoid bone. A possible developmental mechanism behind this phenomenon was revealed using molecular markers during limb development in the Iberian mole (Talpa occidentalis) and a shrew (Cryptotis parva), as shrews represent the closest relatives of moles but do not show these conspicuous elements. The mole's radial sesamoid develops later than true digits, as shown by Sox9, and extends into the digit area, developing in relation to an Msx2-domain at the anterior border of the digital plate. Fgf8 expression, marking the apical ectodermal ridge, is comparable in both species. Developmental peculiarities facilitated the inclusion of the mole's radial sesamoid into the digit series; talpid moles circumvent the almost universal pentadactyly constraint by recruiting wrist sesamoids into their digital region using a novel developmental pathway and timing.