Erik Cattrysse

In Vitro Three Dimensional Morphometry of the Lateral Atlantoaxial Articular Surfaces

Study Design. The present study verifies the 3-dimensional anatomic features of the lateral atlantoaxial joints with reference to a local reference frame using a direct in vitro approach. Objective. To study the concordance between the axial and atlantal articular surfaces. Summary of Background Data. Detailed information of joint-configurations is imperative for understanding the complex kinematics of the upper cervical joint. Data on the quantitative morphology of the human spinal facet joints has been published, but did not include the atlanto-occipital and atlantoaxial joints. Methods. In 20 fresh spine specimens, metal markers were implanted on the cranium, the atlas, and the axis. After registration of the intact specimens, the bony segments were separated and markers and anatomic landmarks were digitized. The size, shape, and orientation relative to the local reference frame of the axis were derived from the relative position data of the joint surface landmarks. Results. The diameters and surface areas of the inferior articular surfaces of the atlas are slightly smaller than the corresponding surfaces on the superior aspects of the axis (17.7 mm and 235 mm2 vs. 17.0 and 212 mm2). In this sample of older-aged specimens, the curvature of the articulating surfaces is nearly flat. The absolute angle between the left and right surface areas is about 130° and corresponds well between axis and atlas. The orientation of the joint surfaces of axis and atlas with respect to the sagittal plane of the axis indicates a good congruency. Conclusion. There seems to be a strong relationship between the anatomic features of the lateral articulating surfaces of atlas and axis. Differences in the orientation of joint surfaces to the frontal plane may be related to deviations from the neutral position. This issue raises the problem of the definition of three-dimensional-neutral joint positions.

Ultrasound of the knee with emphasis on the detailed anatomy of anterior, medial, and lateral structures

ObjectiveTo describe the detailed ultrasound anatomy of the anterior, medial, and lateral aspects of the knee and present the ultrasound examination technique used.Materials and MethodsWe present ultrasound using images of patients, volunteer subjects, and cadaveric specimens. We correlate ultrasound images with images of anatomical sections and dissections.ResultsThe distal quadriceps tendon is made up of different laminas that can be seen with ultrasound. One to five laminas may be observed. The medial retinaculum is made up of three anatomical layers: the fascia, an intermediate layer, and the capsular layer. At the level of the medial patellofemoral ligament (MPFL) one to three layers may be observed with ultrasound. The medial supporting structures are made up of the medial collateral ligament and posterior oblique ligament. At the level of the medial collateral ligament (MCL), the superficial band, as well as the deeper meniscofemoral and meniscotibial bands can be discerned with ultrasound. The posterior part, corresponding to the posterior oblique ligament (POL), also can be visualized. Along the posteromedial aspect of the knee the semimembranosus tendon has several insertions including an anterior arm, direct arm, and oblique popliteal arm. These arms can be differentiated with ultrasound. Along the lateral aspect of the knee the iliotibial band and adjacent joint recesses can be assessed. The fibular collateral ligament is encircled by the anterior arms of the distal biceps tendon. Along the posterolateral corner, the fabellofibular, popliteofibular, and arcuate ligaments can be visualized.ConclusionThe anatomy of the anterior, medial, and lateral supporting structures of the knee is more complex than is usually thought. Ultrasound, with its exquisite resolution, allows an accurate assessment of anatomical detail. Knowledge of detailed anatomy and a systematic technique are prerequisites for a successful ultrasound examination of the knee.

Intra-articular kinematics of the upper limb joints: a six degrees of freedom study of coupled motions

In sport, leisure and certain occupational activities, joint lesions of the upper limb are very common. To understand their aetiology in order to prevent and treat these pathologies on a scientific basis, a comprehensive knowledge of the involved stress and kinematics is imperative. For many years intra-articular joint kinematics have been described hypothetically in terms of the convex–concave principle. This principle, however, has not been validated. The in vitro research on the acromioclavicular, glenohumeral and elbow joints was performed using an electromagnetic tracking device (Flock of Birds). By recalculating the positions of the trackers to an embedded coordinate system on the joint surface, the intra-articular joint movements can be analysed. Therefore, the bony configurations and articular surface features were registered with a 3D drawing stylus (Microscribe). Thirteen acromioclavicular joints, six glenohumeral joints and seven elbows were studied. The coupled intra-articular movements were analysed using the Euler angles and finite helical axis approaches. The results of the acromioclavicular joint analysis indicate that during movements in the scapular plane a superior rotation of the clavicle was coupled with an inferior translation and vice versa, whilst during movements in the plane perpendicular to the scapular plane the anterior rotation was coupled with an anterior translation and vice versa. In the glenohumeral joint, the abduction-elevation was coupled with an external rotation. In the humero-ulnar joint, the extension was coupled with an external rotation and varus movement. This intra-articular behaviour was in contradiction to currently accepted convex–concave concepts in arthrokinematics and manual therapy. The results may have major implications for manual therapy and orthopaedic medical practice.

Brain plasticity in Parkinson’s disease with freezing of gait induced by action observation training

Gait disorders represent a therapeutic challenge in Parkinson’s disease (PD). This study investigated the efficacy of 4-week action observation training (AOT) on disease severity, freezing of gait and motor abilities in PD, and evaluated treatment-related brain functional changes. 25 PD patients with freezing of gait were randomized into two groups: AOT (action observation combined with practicing the observed actions) and “Landscape” (same physical training combined with landscape-videos observation). At baseline and 4-week, patients underwent clinical evaluation and fMRI. Clinical assessment was repeated at 8-week. At 4-week, both groups showed reduced freezing of gait severity, improved walking speed and quality of life. Moreover, AOT was associated with reduced motor disability and improved balance. AOT group showed a sustained positive effect on motor disability, walking speed, balance and quality of life at 8-week, with a trend toward a persisting reduced freezing of gait severity. At 4-week vs. baseline, AOT group showed increased recruitment of fronto-parietal areas during fMRI tasks, while the Landscape group showed a reduced fMRI activity of the left postcentral and inferior parietal gyri and right rolandic operculum and supramarginal gyrus. In AOT group, functional brain changes were associated with clinical improvements at 4-week and predicted clinical evolution at 8-week. AOT has a more lasting effect in improving motor function, gait and quality of life in PD patients relative to physical therapy alone. AOT-related performance gains are associated with an increased recruitment of motor regions and fronto-parietal mirror neuron and attentional control areas.

Measurement of three-dimensional intra-articular kinematics: methodological and interpretation problems.

Intra-articular kinematics evaluates joint motion in terms of the configuration of the joint. Therefore data are needed concerning joint kinematics as well as joint configuration. We have developed accurate measurement methods for both in vivo and in vitro evaluation. Interpretation of the processed data is more complex than simply setting up a coordinate system based on the joint configuration. Although the description of intra-articular motion in terms of Euler–Cardan or helical angles may be complete, the therapeutic interpretation may be doubtful. Using the the ulno-humeral joint during flexion–extension as an example, we found the combination of helical angles in the directions of extension/external rotation/varus. In the case of the Cardan angles, inconsistent patterns of rotation resulted from a different choice of sequence order and were different from the helical angles. The finite helical axis (FHA) provides a functional representation of the joint movement, i.e. pathways of motion, whereas the sequence dependency of Euler–Cardan angles produces problems in the therapeutic interpretation of the movement. Therefore we believe that an FHA approach should be used in intra-articular kinematics research.

Ultrasound of the elbow: A systematic approach using bony landmarks

The use of bony landmarks can be helpful in performing an ultrasound study of the elbow. We discuss bony landmarks that can be used for evaluation of the common extensor tendon, ulnar collateral ligament and common flexor tendon, coronoid and olecranon fossa, ulnar nerve, and biceps tendon. We discuss bony landmarks for each of these structures.

To What Degree Does Active Cervical Range of Motion Differ Between Patients With Neck Pain, Patients With Whiplash, and Those Without Neck Pain? A Systematic Review and Meta-Analysis

OBJECTIVES To quantify differences in active cervical range of motion (aCROM) between patients with neck pain and those without neck pain, in patients with whiplash-associated disorders (WADs) and nontraumatic neck pain, and in patients with acute complaints versus those with chronic complaints. DATA SOURCES Seven bibliographic databases were searched from inception to April 2015. In addition, a manual search was performed. STUDY SELECTION Full articles on a numerical comparison of aCROM in patients with neck pain and asymptomatic control persons of similar ages were included. Two reviewers independently selected studies and assessed risk of bias. DATA EXTRACTION Two reviewers extracted the data. Pooled mean differences of aCROM were calculated using a random-effects model. DATA SYNTHESIS The search yielded 6261 hits; 27 articles (2366 participants, 13 low risk of bias) met the inclusion criteria. The neck pain group showed less aCROM in all movement directions compared with persons without neck pain. Mean differences ranged from -7.04° (95% CI, -9.70° to -4.38°) for right lateral bending (11 studies) to -89.59° (95% CI, -131.67° to -47.51°) for total aCROM (4 studies). Patients with WADs had less aCROM than patients with nontraumatic neck pain. No conclusive differences in aCROM were found between patients with acute and patients with chronic complaints. CONCLUSIONS Patients with neck pain have a significantly decreased aCROM compared with persons without neck pain, and patients with WADs have less aCROM than those with nontraumatic neck pain.

The effect of action observation/execution on mirror neuron system recruitment: an fMRI study in healthy individuals

Action observation and execution activate regions that are part of the motor and mirror neuron systems (MNS). Using functional magnetic resonance (fMRI), we defined the presence and extent of MNS activation during three different motor tasks with the dominant, right-upper limb in healthy individuals. The influence of the modality of task administration (execution, observation, observation and execution) was also investigated. fMRI scans during the execution (E) of a motor task, the observation (O) of a video showing the same task performed by another person and the simultaneous observation and execution (OE) of the task were obtained from three groups of healthy subjects (15 subjects per group) randomized to perform: a simple motor (SM) task, a complex motor (CM) task and a finalistic motor (FM) task. Manual dexterity was assessed using the 9-hole peg test and maximum finger tapping frequency. MNS activation was higher during FM than SM or CM tasks, independently from the modality of administration (E, O, or OE). Inferior frontal gyrus recruitment was more significant during SM than CM tasks in the E and O conditions. Compared to SM and FM, CM task resulted in increased recruitment of brain regions involved in complex motor task performance. Compared to O and E, OE resulted in the recruitment of additional, specific, brain areas in the cerebellum, temporal and parietal lobes. The modality of administration and the type of task modulated MNS recruitment during motor acts. This might have practical implications for the set-up of individualized motor rehabilitation strategies.

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.

Accuracy of peripheral quantitative computed tomography and magnetic resonance imaging in assessing cortical bone cross-sectional area: a cadaver study.

Objective: The present study aimed to assess the accuracy of peripheral quantitative computed tomography (pQCT) and magnetic resonance imaging (MRI) in assessing the cortical cross-sectional area (CCSA) at the level of the tibia. Methods: Nine human whole-leg specimens were scanned with pQCT and MRI (T1-weighted and ultrashort echo-time [UTE] images) at 2 diaphyseal levels, 1 distal and the other 1 proximal. Subsequently, the bones were cut, and the CCSA was measured using digitized planimetry on the transverse sections. The correlation between CCSAs assessed via pQCT and MRI (T1 and UTE images) and assessed via planimetry, taken as a criterion standard, was evaluated using the Spearman rank correlation method. Results: The mean (SD) CCSA with pQCT was 237.3 (54.3) mm2; T1-MRI, 228.8 (63.2) mm2; UTE-MRI, 178.5 (54.8) mm2; and planimetry, 250.17 (59.3) mm2.The CCSA measured with pQCT and T1-MRI was highly correlated with the planimetric CCSA (&rgr; = 0.868 and &rgr; = 0.880, respectively, P < 0.001). The correlation involving UTE-MRI was somewhat weaker (&rgr; = 0.664, P = 0.003). Conclusions: Peripheral quantitative computed tomography and MRI (T1-weighted images) are accurate for the assessment of the CCSA at the tibial shaft.