Superior Articular Surface Research Articles

Typical thoracic vertebrae morphometry: A cadaveric study in Nigeria

Introduction: Spine morphometry is of global interest because of its great importance in prosthetics, orthopedics, and biomechanics. The present study was carried out to provide a comprehensive morphometric data of typical thoracic vertebrae in Nigeria. Material and Methods: A total of 208 typical thoracic vertebrae which consist of 26 set of macerated adult male vertebrae, were studied by direct measurements of the vertebral body, vertebral foramen, pedicle, lamina, spinous and transverse processes, and superior and inferior articular processes. Digital Vernier Caliper was used to measure internal and external distances. Data collected were statistically analyzed and mean values were presented in a mean ± standard deviation. Results: Anterior vertebral body height (VBH) gradually increased to a maximum value at T9 (18.83 ± 1.54 mm) and minimum at T2 (16.93 ± 1.57 mm). Mean value of posterior VBH was minimum at T2 (17.59 ± 1.43 mm) and maximum at T9 (20.46 ± 3.08 mm). Width of spinous process tip had relatively stable values from T2 to T9 with the maximum at T2 (5.05 ± 1.36 mm). Lamina thickness mean values were relatively stable from T2 to T9 with a maximum value at T9 level (7.30 ± 1.24 mm) and the minimum at T2 (6.60 ± 1.16 mm). Discussion and Conclusion: Superior and inferior articular surfaces and Laminae were reported for the first time which contributes to the novelty of this study. These findings will serve as a guidepost in the understanding and design of well-fitted materials for the typical thoracic vertebrae, which will enhance preclinical and clinical evaluation of vertebral implants, prosthetics, and management of spine pathology.

Should the Tibiotalar Angle Be Measured Using an AP or Mortise X-ray?

Category: Basic Sciences/Biologics Introduction/Purpose: The tibiotalar angle(TTA) is an important radiographic tool to determine alignment or malalignment of the ankle and hindfoot.Two methods of measuring the TTA have been described. The midline TTA(MTTA) is when the first line is along the anatomical axis of the tibia, and the second line is along the superior articular surface of the talus. Another method measures a line along the lateral border of the tibia, and a line along the superior articular surface of the talus (the lateral TTA, LTTA). The aims of the study were to compare the two angles as measured on mortise and AP radiographs in normal and pathological cases.We also compared the MTTA and LTTA, to see if they are comparable and if both methods are reliable and reproducible. Methods: A retrospective radiograph review was performed of sequential ankle radiographs taken between 2016 and 2017 across 4 specialist orthopaedic centres in the United Kingdom. Patients were categorised into two distinct groups. In the Normal Group (NG), patients had no evidence of injury and normal radiological appearances. In the Arthritis Group (AG), patients had radiographic changes as per the Kellgren-Lawrence scale 2 to 4. All radiographs were weightbearing and classified as either AP or mortise views based on the position of the talus and overlap of the tibia and fibula. The MTTA and the LTTA were measured on each radiograph. Results: There were 320 radiographs for review;158 normal radiographs and 162 radiographs had arthritis.There were 117 AP and 203 mortise radiographs. The overall mean MTTA was 88.7±5.1 degrees(range 77-104), and the mean LTTA was 87.5±5.2 degrees(range 73-104);p<0.01.There was no significant difference between the MTTA and LTTA in the normal group. There was a significant difference(p<0.01) when comparing the MTTA and LTTA in the arthritis group(Table 1). There was no significant difference when the MTTA was measured between the AP and Mortise radiographs. There was a significant difference in the LTTA between AP and mortise radiographs(p=0.04). There was no significant difference between the MTTA or LTTA when measuring the angles on AP radiographs(p=0.09).However, there was a significant difference when measuring these angles in the mortise radiographs(p=0.02). Conclusion: Understanding the tibiotalar angle is key to planning for deformity correction. It is important that consistency of methods for measurement are used for reporting. In this paper we have shown the MTTA to be a reliable and reproducible tool for measuring the TTA, in both normal ankle radiographs and in patients with ankle arthritis. There is no significant difference when the MTTA is measured using an AP or a mortise radiograph. In contrast, we have shown that the LTTA to be unreliable and statistically different when measured on both AP and mortise radiographs.

Les lésions de la racine postérieure du ménisque médial induisent une extrusion méniscale postérieure anormale en semi-flexion : étude en IRM ouverte

BackgroundA medial meniscus posterior root tear (MMPRT) is defined as an injury to the posterior meniscal insertion on the tibia. In MMPRT, the medial meniscus (MM) hoop function is damaged, and the MM undergoes a medial extrusion into the interior from the superior articular surface of the tibia. However, the details of MM position and movement during knee joint movement are unclear in MMPRT cases. The present study aims to evaluate MM position and movement via magnetic resonance imaging (MRI) examination of the MM posterior extrusion (MMPE) at knee flexion angles of 10° and 90°. We hypothesized that, during knee flexion, the MM will shift to the posterior and the posterior extrusion will increase compared to that when the knee is extended. Materials and methodsTwenty-four patients were diagnosed with symptomatic MMPRT on open MRI examination. Preoperative MMPE, anteroposterior interval (API) of the MM, and MM medial extrusion (MMME) at knee flexion angles of 10° and 90° were measured. ResultsFor patients with MMPRT, the MMPE increased from −4.77±1.43mm to 3.79±1.17mm (p<0.001) when the knee flexion angle increased from 10° to 90°. Further, flexing the knee from 10° to 90° decreased the API of the MM from 20.19±4.22mm to 16.41±5.14mm (p<0.001). MMME showed no significant change between knee flexion angles of 10° and 90°. DiscussionThis study demonstrated that, in cases of MMPRT, the MMPE clearly increases when the knee is flexed to 90°, while MMME does not change. Our results suggest that open MRI examination can be used to evaluate the dynamic position of the posterior MM by scanning the knee as it flexes to 90°. Level of evidenceIV retrospective cohort study.

Medial meniscus posterior root tear induces pathological posterior extrusion of the meniscus in the knee-flexed position: An open magnetic resonance imaging analysis.

A medial meniscus posterior root tear (MMPRT) is defined as an injury to the posterior meniscal insertion on the tibia. In MMPRT, the medial meniscus (MM) hoop function is damaged, and the MM undergoes a medial extrusion into the interior from the superior articular surface of the tibia. However, the details of MM position and movement during knee joint movement are unclear in MMPRT cases. The present study aims to evaluate MM position and movement via magnetic resonance imaging (MRI) examination of the MM posterior extrusion (MMPE) at knee flexion angles of 10° and 90°. We hypothesized that, during knee flexion, the MM will shift to the posterior and the posterior extrusion will increase compared to that when the knee is extended. Twenty-four patients were diagnosed with symptomatic MMPRT on open MRI examination. Preoperative MMPE, anteroposterior interval (API) of the MM, and MM medial extrusion (MMME) at knee flexion angles of 10° and 90° were measured. For patients with MMPRT, the MMPE increased from -4.77±1.43mm to 3.79±1.17mm (p<0.001) when the knee flexion angle increased from 10° to 90°. Further, flexing the knee from 10° to 90° decreased the API of the MM from 20.19±4.22mm to 16.41±5.14mm (p<0.001). MMME showed no significant change between knee flexion angles of 10° and 90°. This study demonstrated that, in cases of MMPRT, the MMPE clearly increases when the knee is flexed to 90°, while MMME does not change. Our results suggest that open MRI examination can be used to evaluate the dynamic position of the posterior MM by scanning the knee as it flexes to 90°. IV: retrospective cohort study.

Neural Network as an Assisting Tool in Designing Talus Implant

The design of current talus implant are focusing too much on mechanical simplicity and usually based on certain population which tends to ignore the anatomically difference between populations. An anatomically talus implant design is known can reduce the contact pressure but one of the constraints for designing implant anatomically is to get bone parameters. This is due to the difficulty to get enough volunteers in getting bone parameters using hazardous method (X-ray or CT scan) .Thus, the talus implant (TI) for particular population was developed based on artificial neural network (ANN) prediction. By using Finite Element Method (FEM), numerical models that include mainly the talus bone and the talus implants are created to compare the contact pressure distribution of the newly develop talus implant with the three different kind of current talus implant designs (BOX, STAR &amp; TNK). For FEM results, only BOX and the newly develop talus implant exceeded the contact stress recommended for the superior articular surface compared to the others. The results also showed that the stress increased near the resected surface. Thus, it is agreed that excessive bone resection may not support the force at the ankle which consequently may contribute to early loosening and subsidence of the talus implant. It is concluded that the excessive bone resection can be avoided by perfectly match talus implant which only can be achieved by designing talus implant for a particular population.

Desenvolvimento de um guia paciente‐específico para fixação de coluna cervical alta

ObjectiveHigh cervical spine fixation represents a challenge for spine surgeons due to the complex anatomy and the risks of vascular and medullar injury. The recent advances in 3D printing have unfolded a whole new range of options for these surgeons. MethodsIn this study, a guide for the placement of the lateral mass screw in C1 was developed using 3D printing. Eight real‐size models of the high cervical spine and their respective screw guides were built using CT scan images. The guidewires were inserted with the help of the printed guides and then the models were analyzed with the help of CT scan images. ResultsAll the guidewires in this study obtained a safe placement in the models, avoiding the superior and inferior articular surfaces, the vertebral foramen, and the vertebral artery. ConclusionThe study demonstrated the efficiency of the guide, a reliable tool for C1 lateral mass screws guidewire insertions.

Anatomical Consideration for Posterior Atlantoaxial Transarticular Screw Fixation from Reformatted Two-Dimensional CT Images

Background: Posterior transarticular C1-C2 fixation by screw is a widely used technique to correct atlantoaxial instability. However, the screw trajectory must be precise because the adjacent vital organs include the spinal cord and vertebral artery in the transverse foramen. Due to the lack of an objective measuring method, clarifying the range of the safe zone of screw trajectory in both the sagittal and coronal planes is important. Objective: To clarify the safe zone and ideal trajectory for screw fixation ensuring safety and without violating the transverse foramen and spinal canal. Methods: Radiographs of the normal upper cervical spine and coronal reconstruction CT scans from the entry point of the screw on C2 was performed and the safe zone for the screw path was drawn. The points of screw intersection on the superior articular surface of C2 were measured from the posterior rim of the superior articular surface of C2 then the safe zone of the screw in the coronal plane was drawn in the coronal oblique plane along the screw direction. Results: Average safe zone in the sagittal plane was 51.6 – 61.2 relative to the superior articular of C2 and the safe zone in the coronal view was medially 9.5 and laterally 4.2 relative to the midline of the spinous process. The safe zone and ideal screw trajectory should intersect C2 at 8.03 and 4.5 mm from the posterior rim of the superior articular surface on C2. Conclusion: The result of this study showed the range of the safe zone of the posterior atlantoaxial screw trajectory that guides to minimize the risk of misdirection and violating the transverse foramen by the screw. The areas on the superior articular of C2 intersected by the trajectories making the longest paths are guides to purchase the longest path of bone to achieve more stability and pullout strength

Types of facets on the superior articular surface of dried human calcanei

To evaluate the prevalence of pterygium and its determinants in the underserved, rural population of Iran.In this cross-sectional study of 3851 selected individuals, 86.5% participated in the study, and the prevalence of pterygium was evaluated in 3312 participants. A number of villages were selected from the north and south of Iran using multistage cluster sampling. Pterygium was diagnosed by the ophthalmologist using slit-lamp examination.The mean age of the study participants was 37.3 ± 21.4 years (2–93 years), and 56.3% (n = 1865) of them were women. The prevalence of pterygium was 13.11% [95%confidence interval (CI):11.75–14.47]. The prevalence of pterygium was 14.99 (95%CI:12.79–17.19) in men and 12.07 (95%CI:10.3–13.84) in women. Pterygium was not seen in children below the age of 5 years. The prevalence of pterygium increased linearly with age; the lowest and highest prevalence of pterygium was observed in the age group 5–20 years (0.19%) and 61–70 years (28.57%). Evaluation of the relationship between pterygium with age, sex, educational level, and place of living using a multiple model showed that age, living in the south of Iran, and low educational level were correlated with pterygium.The prevalence of pterygium was significantly higher in Iranian villages when compared with the results of previous studies. This finding may represent the effect of a rural lifestyle and its risk factors.

Morphometry of superior articular surface of head of radius

Morphometry of superior articular surface of head of radius

A Collapse that Led to Shoulder Pain

HISTORY: A 55 year old female presents for right shoulder pain. She has a history of multiple sclerosis, recent falls complicated by a right 6th rib fracture and a right 4th phalanx fracture, a 35 pack year history of tobacco use, and an unknown fracture of her right shoulder sustained at age 16. Her current shoulder pain began four weeks prior to her visit while reaching behind her back in the shower. She felt like her shoulder popped out of place. She has achy pain, worse when touching her shoulder or using her walker. It improves with lying down and with a sling. Acetaminophen and ibuprofen do not provide relief. Physical therapy as part of her multiple sclerosis treatment has not helped. PHYSICAL EXAMINATION: BP: 122/82, Pulse: 69, Respirations: 16, SpO2: 96%. Shoulder: - No gross abnormality, no step-offs along the clavicle. - Tender over the entire humeral head and anterior shoulder. - No swelling, warmth, or erythema. - ROM: o Right flexion 85 degrees active, 95 degrees passive. o Right abduction 90 degrees active, 100 degrees passive. o Adduction, internal rotation, external rotation and extension were full and equal bilaterally. - 5/5 strength - Special tests: positive empty can, Hawkin’s, O’Brien’s, and Speed’s test. Negative crossed arm adduction, AC compression, and sulcus sign. Unable to perform Neer’s test due to pain. DIFFERENTIAL DIAGNOSIS: Torn rotator cuff Glenohumeral arthritis Humeral head fracture as part of Osteogenesis Imperfecta Avascular necrosis AC joint arthritis Shoulder dislocation/subluxation Elder Abuse TEST AND RESULTS: Shoulder 3 view XR: - Extensive posttraumatic deformity of proximal right humerus with marked irregularity of articular surface. - Possible non-displaced superimposed acute or subacute fracture - Slightly displaced posterolateral right 4th and 5th rib fractures Shoulder MRI: - Marked abnormality of the right humeral head with contour deformity - Progressive collapse of superior articular surface, with focal marrow edema. This may be posttraumatic or relate to avascular necrosis - No rotator cuff tear. FINAL WORKING DIAGNOSIS: Avascular necrosis of the humeral head TREATMENT AND OUTCOMES: - Placed in arm sling for pain control - Referred for surgical replacement of the humeral head - Referred for workup for osteogenesis imperfecta, given multiple fractures

Anatomic Humeral Head Reconstruction With Fresh Osteochondral Talus Allograft for Recurrent Glenohumeral Instability With Reverse Hill-Sachs Lesion

The treatment of recurrent glenohumeral instability, especially with a concomitant bony lesion, remains challenging. This is especially true in the case of posterior instability given its less common incidence. Moreover, the presence of an engaging reverse Hill-Sachs lesion in combination with posterior instability will result in the need for a more aggressive treatment option. In comparison with a Hill-Sachs lesion, a reverse Hill-Sachs lesion features greater chondral deficiency that must be addressed during treatment. We propose the talus allograft as a potential allograft for treatment of an engaging reverse Hill-Sachs lesion. The superior articular surface of the talus may be used to reconstruct the articular surface of the humeral head. In this technical note, we describe our preferred primary technique for treatment of an engaging reverse Hill-Sachs lesion with recurrent glenohumeral instability through use of a fresh osteochondral talus allograft, as well as discuss the advantages and disadvantages of this allograft option.

Morphometry of the superior articular surface of head of radius

The human elbow joint has three different articulations surrounded by a common joint capsule. These joints are the humeroulnar joint, humeroradial joint, and the proximal radioulnar joint. The humeroradial joint is a shallow ball-and-socket, hinge type of synovial joint. This aims to provide morphometric data concerning the superior articular surface of the head of radius. In a sample of 30 dry specimen of the radius, high-precision measurements were recorded to derive a statistical inference concerning: the maximal depth of the superior articular surface, its average diameter, and the articular surface area and its concavity volume. The depth and the diameter were measured using an electronic Vernier. Measuring the surface area and volume at such a small-scale was a challenge. Hence, three methods were deployed: a mathematical method, a cast material technique, and a low-surface tension fluid application.The 95% confidence intervals were 1.847–2.119mm (depth), 18.963–20.445mm (diameter), 2.961–3.451cm2 (surface area), and 0.277–0.359cm3 (volume). There was a strong positive correlation for: depth vs. volume, depth vs. area, area vs. volume, diameter vs. depth, diameter vs. area, and diameter vs. volume. However, the correlation was absent (not significant) for age vs. diameter (p-value 0.361), age vs. depth (p-value 0.937), age vs. area (p-value 0.342), age vs. volume (p-value 0.512), limb orientation vs. area (p-value 0.149), limb vs. volume (p-value 0.146). This is the first study of its kind, to analyze the morphometry of the superior articular surface of the radial head, both experimentally and statistically. Derived data are of high impact in standardization and practical application in anthropology, biotechnology and biomedical applications, orthopedics, and rheumatology.

The Anatomic Midpoint of the Attachment of the Medial Patellofemoral Complex

The medial patellofemoral ligament varies in attachment of its fibers to the patella and vastus intermedius tendon. Our aim was to identify and describe its anatomic midpoint. To account for the variability of the attachment site, we refer to it as the medial patellofemoral complex. Using AutoCAD software, we identified the midpoint of the medial patellofemoral complex attachment on photographs of 31 cadaveric knee dissections. The midpoint was referenced relative to the superior articular surface of the patella (P1) and was described in terms of the percentage of the patellar articular length distal to this point. A second point, at the junction of the medial border of the vastus intermedius tendon with the superior articular border of the patella, was identified (P2). The distances of the midpoint to P1 and P2 were calculated and were compared using paired t tests. Twenty-five images had appropriate quality and landmarks for digital analysis. The midpoint of the medial patellofemoral complex was located a mean (and standard deviation) of 2.3% ± 15.8% of the patellar articular length distal to the superior pole and was at or proximal to P1 in 12 knees. In all knees, the midpoint was at or proximal to P2. After exclusion of 2 knees with vastus intermedius tendon attachments only, the medial patellofemoral complex midpoint was closer to P2 (5.3% ± 8.6% of the patellar articular length) than to P1 (9.3% ± 8.5% of the patellar articular length) (p = 0.06). The midpoint of the medial patellofemoral complex was 2.3% of the articular length distal to the superior pole of the patella. Additionally, we describe an anatomic landmark at the junction of the medial border of the vastus intermedius tendon and the articular border of the patella that approximates the midpoint of this complex. Our study shows that the anatomic midpoint of the attachment of the medial patellofemoral complex is proximal to the junction of the medial vastus intermedius tendon and the articular border of the patella, suggesting that graft placement may be more anatomic on the vastus intermedius tendon rather than on the patella.

Morphogenetically active scaffold for osteochondral repair (polyphosphate/alginate/N,O-carboxymethyl chitosan).

Here we describe a novel bioinspired hydrogel material that can be hardened with calcium ions to yield a scaffold material with viscoelastic properties matching those of cartilage. This material consists of a negatively charged biopolymer triplet, composed of morphogenetically active natural inorganic polyphosphate (polyP), along with the likewise biocompatible natural polymers N,O-carboxymethyl chitosan (N,O-CMC) and alginate. The porosity of the hardened scaffold material obtained after calcium exposure can be adjusted by varying the pre-processing conditions. Various compression tests were applied to determine the local (nanoindentation) and bulk mechanical properties (tensile/compression test system for force measurements) of the N,O-CMC-polyP-alginate material. Determinations of the Young's modulus revealed that the stiffness of this comparably water rich (and mouldable) material increases during successive compression cycles to values measured for native cartilage. The material not only comprises viscoelastic properties suitable for a cartilage substitute material, but also displays morphogenetic activity. It upregulates the expression of genes encoding for collagen type II and aggrecan, the major proteoglycan within the articular cartilage, in human chondrocytes, and the expression of alkaline phosphatase in human bone-like SaOS-2 cells, as revealed in RT qPCR experiments. Further, we demonstrate that the new polyP-based material can be applied for manufacturing 3D solid models of cartilage bone such as of the tibial epiphyseal plate and the superior articular cartilage surface. Since the material is resorbable and enhances the activity of cells involved in regeneration of cartilage tissue, this material has the potential to be used for artificial articular cartilage implants.

Morphometry of the articular facets on the superior, medial and lateral surfaces of the body of talus and its clinical relevance

Background: In the formation of Ankle joint, tibio-fibular mortice receives superior, medial and lateral articular surfaces of body of Talus. Because of very limited availability of the data on the Morphometry of the articular facets on the Body of the dry human tali, this study was undertaken. Aims: To prepare the database on the articular facets on the superior, medial and lateral surfaces of body of talus, to find if there is statistically significant difference between both the sides of measurements and to compare the results with the previous studies. Methods and Material: 40 Dry Human Tali (20 Right and 20 Left) were measured with Digital vernier caliper for the following Measurements: On the Trochlear surface: Medial length, Central length, Lateral length, Anterior width, Central width, Posterior width. On the lateral triangular articular facet: Central height, Central width. On the coma shaped medial articular facet: Central height, Central width. Results: Mean values of Medial, Central and Lateral lengths were 31.02, 30.39 and 29.63mm on Right side and 31.79, 30.65 and 29.45mm on Left side. Mean Anterior, Central and Posterior widths were 28.87, 28.16 and 21.59mm on right side and 29.08, 27.54 and 21.78mm on left side. On the medial articular surface, mean central height was 11.93mm on the right side and 11.29mm on the left side, Mean central width was 27.94mm on the right side and 28.29mm on the left side. On the lateral articular surface, mean central height was 22.14mm on the right side and 22.63mm on the left side. Mean central width was 18.93mm on the right side and 18.99mm on the left side. There is no significant difference between right and left sides of measurements. Conclusion: The trochlear articular surface is wider in front, measurements of opposite talus bone can be used as a control during talus bone replacement surgery, it may help surgeons to plan pre-operatively the complex talar fracture surgeries, to design accurate talus bone prosthesis and talus implants.

Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area.

Background:Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA) of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement.Materials and Methods:ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools.Results:Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41), 42.49 (8.15) and 55.26 (10.08) degrees, respectively.Conclusions:Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively.

The potential effect of anatomic relationship between the femur and the tibia on medial meniscus tears

The anatomic and the kinematical relationships between the femur and the tibia have been previously examined in both normal and diseased knees. However, less attention has been directed to the effect of these relationships on the meniscal diseases. Therefore, we aimed to investigate the impact of femorotibial incongruence on both lateral and medial meniscal tears. A total of 100 images obtained from MRI of 100 patients (39 males and 61 females) were included in the study. Diameters of the medial and the lateral femoral condyles, thicknesses of the menisci, and diameters of the medial and the lateral tibial articular surfaces were measured. The medial meniscus tear was detected in 40 (40%) patients. However, no lateral meniscus tear was found. Significant relationships were found between the diameters of the posterior medial femoral condyle and the medial tibial superior articular surface and between the diameters of the posterior lateral femoral condyle and the lateral tibial superior articular surface. The mean values for the diameter of the medial condyle of the femur, the lateral condyle of the femur, the medial superior articular surface of the tibia, and the lateral superior articular surface of the tibia were found to be significantly higher in cases with meniscus tear compared to cases without meniscus tear. However, no significant difference was present regarding the thicknesses of the medial and the lateral menisci. A positive relationship between the diameter of the posterior medial femoral condyle and the tibial medial superior articular surface was found in cases with (n=40) (r (2)=0.208, p=0.003) and without tear (n=60) (r (2)=0.182, p=0.001). In addition, a significant positive relationship was found between the diameter of the posterior medial femoral condyle and the medial tibial superior articular surface in cases with and without tear. The impact of femorotibial incongruence on the medial meniscus tear is important for the understanding of the lesions.

Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

To describe a type of meniscus flap tear resembling a bucket-handle tear, named a "hemi-bucket-handle" tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears. Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears. A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign. We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear.

Morphology of sustentaculum tali: Biomechanical importance and correlation with angular dimensions of the talus

Summary of background data The talus and the calcaneus share the bulk of load transmitted from the leg to the skeleton of the foot. The present study analyses the inter-relationship between the superior articular surface and the angular dimensions of the talus with the morphology of the sustentaculum tali. Objective Identification of possible relationships between different angular parameters of the talus morphology and the sustentaculum tali in context of load transmission through the foot. Methods One articular surface and three angular parameters at the junction of the head and the body were measured from dried human talar bones. Corresponding calcaneal samples were measured for four dimensions at the sustentaculum tali. Correlation and regression statistical values between parameters were worked out and analysed. Results Several parameters within the talus demonstrated significant correlations amongst themselves. The neck vertical angle showed a strong correlation with the articulating surface area below the head of the talus. Conclusions The inter-relationship between articular and angular parameters within the talus demonstrates strong correlation for certain parameters. Data presented in the study may be helpful to adjust calcaneal and talar screw placement techniques, prosthesis designing and bio-mechanical studies at this important region.

In vitro characterization of the anterior to posterior curvature of the superior articular facets of the atlas as a function of age

Background context Reference is made in the literature to the inherent instability of the atlantooccipital joint in infants and young children because of pliant ligaments, undeveloped musculature, smaller condyles, and the relative lack of anteroposterior curvature of the superior articular facet surfaces of the atlas. The combination of these morphologic factors is purported to make this population particularly vulnerable to whiplash-type injuries. Although a significant difference in the magnitude of the anteroposterior curvature of the superior articular facet surfaces of the atlas between young children and adults has been observed, quantitative analysis of the curvature of these surfaces has not been documented. Purpose To quantify the anterior to posterior curvature of the superior articular facet surfaces of the atlas as a function of age. Study design This study is a retrospective analysis of the anterior to posterior curvature of the superior articular facet surfaces of the atlas as a function of age in 15 pediatric cadaver specimens from the Hamann-Todd Osteology Collection in Cleveland, Ohio, and 18 adult cadaver specimens from the Department of Experimental Anatomy in Brussels, Belgium. Methods A stylus, connected to a three-dimensional digitizer, was used to manually define a series of points on the perimeter of the superior articular facet surfaces of the atlas of each specimen. The digitized data points were then used to generate two planes that approximated the anterior and posterior aspects of the articular surfaces in three-dimensional space. A line through a point on each plane and perpendicular to that plane was defined for each of the two planes. The angle between the two perpendicular lines was calculated and used to quantify the curvature of the facet surface. Results The anteroposterior curvature of the superior articular facet surfaces of the atlas increases from an average angle of 11.5 (±4.7) degrees at 1 year of age and asymptotically approaches an average angle of 43.5 (±13.4) degrees at 80 years of age. There is a direct relationship between age and the anterior to posterior curvature of the superior articular surfaces of the atlas that can be approximated (r 2=0.94) with a sigmoid function. Ninety percent of the final curvature is achieved at approximately 8 years of age.