Kazuomi Sugamoto

Kinematics of the subaxial cervical spine in rotation in vivo three-dimensional analysis

Study Design. Kinematics of the upper cervical spine during head rotation were investigated using three-dimensional magnetic resonance imaging (MRI) in healthy volunteers. Objectives. To demonstrate in vivo intervertebral coupled motions of the upper cervical spine. Summary of Background Data. Although various in vivo and in vitro studies have identified the normal movement patterns of the upper cervical spine, no previous studies have accurately analyzed in vivo three-dimensional intervertebral motions of the upper cervical spine during head rotation. Methods. Fifteen healthy volunteers underwent three-dimensional MRI of the upper cervical spine using a 1.0-T imager in progressive 15° steps during head rotation. Segmented three-dimensional MRIs of each vertebra in the neutral position were superimposed over images taken at other positions, using voxel-based registration. Relative motions between occiput (Oc) and atlas (C1) and between C1 and axis (C2) were measured and described with 6 degrees of freedom by rigid body Euler angles and translations. Results. Mean (± SD) maximum angles of axial rotation in Oc–C1 and C1–C2 were 1.7 ± 1.5° and 36.2 ± 4.5° to each side, respectively. Increases in angle of axial rotation in C1–C2 became smaller with increased head rotation, indicating axial rotation in C1–C2 displayed nonlinear motion. Coupled lateral bending with axial rotation was observed in the direction opposition to that of axial rotation in Oc–C1 (mean, 4.1 ± 1.4°) and C1–C2 (mean, 3.8 ± 3.0°). Coupled extension with axial rotation occurred at both C0–C1 (mean, 13.3 ± 4.9°) and C1–C2 (mean, 6.9 ± 3.0°). Conclusions. We developed an innovative in vivo three-dimensional motion analysis system using three-dimensional MRI. In vivo coupled motions of the upper cervical spine investigated using this system supported the results of the previous in vitro study.

Improvement of depth position in 2-D/3-D registration of knee implants using single-plane fluoroscopy

Two-dimensional (2-D)/three-dimensional (3-D) registration techniques using single-plane fluoroscopy are highly important for analyzing 3-D kinematics in applications such as total knee arthroplasty (TKA) implants. The accuracy of single-plane fluoroscopy-based techniques in the determination of translation perpendicular to the image plane (depth position), however, is relatively poor because a change in the depth position causes only small changes in the 2-D silhouette. Accuracies achieved in depth position using conventional 2-D/3-D registration techniques are insufficient for clinical applications. Therefore, we propose a technique for improving the accuracy of depth position determination in order to develop a system for analyzing knee kinematics over the full six degrees of freedom (6 DOF) using single-plane fluoroscopy. In preliminary experiments, the behaviors of errors for each free variable were quantified as evaluation curves by examining changes in cost function with variations in the free variable. The evaluation curve for depth position was more jagged, and the curve peak less pointy, compared to the evaluation curves of the other five variables, and the curve was found to behave differently. Depth position is therefore optimized independently of the other variables, using an approximate evaluation curve of depth position prepared after initial registration. Accuracy of the proposed technique was evaluated by computer simulation and in vitro tests, with validation of absolute position and orientation performed for each knee component. In computer simulation tests, root-mean-square error (RMSE) in depth position was improved from 2.6 mm (conventional) to 0.9 mm (proposed), whereas for in vitro tests, RMSE improved from 3.2 mm to 1.4 mm. Accuracy of the estimation of the remaining two translational and three rotational variables was found to be almost the same as that obtained by conventional techniques. Results of in vivo tests are also described in which the possibility of full 6 DOF kinematic analysis of TKA implants is shown.

Localization of bone morphogenetic protein-2 in human osteoarthritic cartilage and osteophyte

OBJECTIVESnTo examine the localization of bone morphogenetic protein (BMP)-2 mRNA and protein in human osteoarthritic (OA) articular cartilage and osteophyte.nnnDESIGNnFive normal, four growing and 14 OA human cartilage samples, graded histomorphologically by Mankin Score, were studied by in situ hybridization and immunohistochemistry for the expression of BMP-2.nnnRESULTSnBMP-2 mRNA was present in chondrocytes in neonatal growing articular cartilage, but was scarcely present in normal adult articular cartilage. In OA articular cartilage, BMP-2 mRNA and protein were detected in both clustering and individual chondrocytes in moderately or severely damaged OA cartilage. In moderately damaged OA cartilage, BMP-2 mRNA was localized in both upper and middle zone chondrocytes, but was not detected in deep layer chondrocytes. In severely damaged OA cartilage, cellular localization of BMP-2 mRNA was extended to the deep zone. In the area of osteophyte formation, BMP-2 mRNA was intensely localized in fibroblastic mesenchymal cells, fibrochondrocytes, chondrocytes and osteoblasts in newly formed osteophytic tissue. The pattern of BMP-2/4 immunolocalization was associated with that of mRNA localization.nnnCONCLUSIONSnBMP-2 mRNA and BMP-2/4 were detected in cells appearing in OA tissues. BMP-2 was localized in cells of degenerating cartilage as well as osteophytic tissue. Given the negative localization of BMP-2 in normal adult articular cartilage, BMP-2 might be involved in the regenerating and anabolic activities of OA cells, which respond to cartilage damage occurring in osteoarthritis.

Comparison between mobile-bearing and fixed-bearing knees in bilateral total knee replacements

The purpose of this study was to compare mid-term results of mobile-bearing and fixed-bearing in bilateral total knee arthroplasty (TKA). Twenty-two patients underwent bilateral TKA with a mobile-bearing prosthesis (Rotaglide, Corin, UK) on one side and a fixed-bearing prosthesis (NexGen-CR, Zimmer, USA) on the other. There were 21 female patients, and in 18 patients, the diagnosis was rheumatoid arthritis. The average age was 59.6 (35–78) years. In all procedures, the posterior cruciate ligament was retained and patella re-surfaced. The average follow-up in the mobile-bearing group was 98 (79–107) months and 96 (79–107) months in the fixed-bearing group. At the final follow-up, the knee score was 91.8 points and 91.1 points, respectively, and the function score 65.5 points. The range of motion was similar in the two groups (1.1–106.9°; 0.4–106.9°). Five patients favoured the fixed-bearing prosthesis, but 16 found no difference. In patients with bilateral TKA, there was no difference in the short-term result between mobile-bearing and fixed-bearing prostheses.RésuméLe but de cette étude était de comparer les résultats à moyen terme des plateaux fixes et des plateaux mobiles dans l’arthroplastie totale du genou bilatérale (TKA). Vingt-deux malades ont eu une arthroplastie bilatérale avec une prothèse à plateau mobile (Rotaglide, Corin, ROYAUME-UNI) d’un côté et une prothèse à plateau fixe (NexGen-CR, Zimmer, USA) de l’autre. Il y avait 21 femmes et, pour 18 malades le diagnostic était polyarthrite rhumatoïde. L’âge moyen était 59.6 (35–78) ans. Dans tous les cas, le ligament croisé postérieur a été conservé et la rotule resurfacée. Le suivi moyen dans le groupe plateau mobile était 98 (79–107) mois et 96 (79–107) mois dans le groupe plateau fixe. Au dernier recul le score du genou était 91,8 points et 91,1 points respectivement et le score fonctionnel de 65,5 points. L’amplitude de mouvement était semblable dans les deux groupes (1.1–106.9° resp. 0.4–106.9°). Cinq malades préfèraient la prothèse à plateau fixe mais 16 n’ont trouvé aucune différence. Chez les malades avec une arthroplastie bilatérale du genou il n’y avait aucune différence dans les résultat à court terme entre les prothèses à plateau fixe et celles à plateau mobile.

Total ankle replacement in rheumatoid arthritis

We reviewed 21 patients with rheumatoid arthritis who had a total ankle replacement between 1984 and 2000. The average follow-up was 72 (15–169) months. Clinical results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score. At the latest review, three ankles had been revised. Two ankles were excellent, seven good, three fair, and 12 poor. Eleven patients with 13 ankles had residual pain, with radiographs showing a high incidence of radiolucent lines. Migration of the tibial component was seen in 13 ankles and collapse of talus in nine. Although clinical results were poor, patient satisfaction was not.RésuméNous avons examiné 21 malades atteint de polyarthrite rhumatoïde qui avaient eu une prothèse totale de la cheville entre 1984 et 2000. La moyenne de suivi était de 72 mois (15–169). Les résultats cliniques ont été évalués avec le score de la Société Américaine du Pied et de la Cheville. À la révision la plus tardive, trois chevilles avaient été réopéreés. Deux chevilles avaient un résultat excellent, sept un bon, trois un résultat moyen et 12 un mauvais résultat. Onze malades, avec 13 chevilles opérées, avaient des douleurs résiduelles, avec une grande fréquence de liserés radiologiques. La migration du composant tibial a été notée dans 13 chevilles et l’enfoncement de l’astragale dans neuf chevilles. Bien que les résultats cliniques étaient assez mauvais, les patients étaient plutôt satisfaits.

Glenoid shape in atraumatic posterior instability of the shoulder

Glenoid shape is related closely to shoulder stability and its abnormality is thought to affect the humeral head position in shoulders with atraumatic instability. However, it is unclear how the glenoid shape in shoulders with atraumatic instability is different from the glenoid shape in normal shoulders. The current authors investigated glenoid shape of 45 healthy individuals (20 males and 25 females; average age, 22 years) and 20 patients with atraumatic posterior instability with multidirectional laxity (six males and 14 females; average age, 19 years) using three-dimensional magnetic resonance imaging. The tilting angles of the glenoid bone were measured in five consecutive planes perpendicular to the long axis of the glenoid and cross sections were divided into three types (concave, flat, convex). In healthy individuals, the average tilting angles from the bottom to the top of the glenoid bone were 3.0° ± 3.6°, 1.0° ± 3.2°, −1.0° ± 2.0°, −2.3° ± 3.9°, and −6.9° ± 3.7° anteriorly, and tilting angles of patients were −6.1° ± 4.0°, −4.0° ± 3.6°, −4.8° ± 3.2°, −5.5° ± 2.7°, and −7.5° ± 3.1°. The type of cross section also was different on the bottom plane where the concave shape accounted for 78% of healthy individuals whereas it accounted for 0% of patients. The loss of tilting angles and concavity of the inferior glenoid would correlate with the direction of the head translation in posterior instability.

Evaluation of three-dimensional glenoid structure using MRI

The tilting angle and the shape of the glenoid cavity are considered to relate closely to shoulder stability. They are also important when planning arthroplasty and developing new designs. This study examines the glenoid cavity using 3‐dimensional MRI. Forty volunteers (20 men, 20 women; average age 21.4; range 18–35 y) were enrolled in the study. The tilting angles of the glenoid bone were measured in 5 consecutive axial planes perpendicular to the glenoidal long axis. Cross sections were divided into 3 types (concave, flat, convex) according to the shape on each plane.

The triquetrum-hamate joint: An anatomic and in vivo three-dimensional kinematic study

PURPOSEnTo obtain anatomic and kinematic information regarding the relative motion of the triquetrum-hamate (TqH) joint.nnnMETHODSnIn this anatomic study the contact surface constraints of the TqH joint that affect TqH motion were investigated by passively simulating TqH motion according to the kinematic data. Two fresh and 28 embalmed cadaver wrists were dissected. In the kinematic study we studied the in vivo 3-dimensional (3D) kinematics of the TqH joint during radioulnar deviation (RUD) and wrist flexion and extension motion (FEM) in 5 healthy wrists using a magnetic resonance image (MRI)-based markerless bone registration algorithm. Animations of the relative motion of the TqH joint were created and accurate estimates of the relative positions and orientations of the bones and axes of rotation of TqH motion during RUD and FEM were obtained.nnnRESULTSnThe anatomic study revealed that the contact surface constraints of the TqH joint include primarily the oval convex surface of the hamate. In the kinematic study TqH motion was likely to be not helicoidal but rotational around an oval convex surface of the hamate. In RUD the triquetral movement was rotation in an ulnoflexion-radial extension plane of the wrist. In FEM it was rotation in an almost flexion-extension plane of the wrist. The axes of rotation of the TqH joint in all wrist motions always ran distal to the TqH joint.nnnCONCLUSIONSnTypical motion of the TqH joint in functional range of motion is not a helicoidal motion on the saddle, but rather a rotational motion on an oval, whose axes of rotation are located on the distal side of the joint.

Localization and expression of osteopontin in the rotator cuff tendons in patients with calcifying tendinitis

Abstract. Calcifying tendinitis of rotator cuff tendons is a common and painful condition caused by ectopic calcification in humans. To examine the involvement of osteopontin (OPN), a potent regulator of calcium deposition on connective tissues, localization and expression of OPN protein and messenger (m)RNA were investigated in human tissue samples of calcified rotator cuff tendons. Immunohistochemistry demonstrated that OPN was localized in cells surrounding the calcified area. OPN was localized in two distinct cell types, i.e., fibroblast-like cells negative for CD68 and tartrate-resistant acid phosphatase (TRAP) and multinucleated macrophages positive for CD68 and TRAP. In situ hybridization revealed that the mRNA expression of OPN in these cells coincided with the immunohistochemistry results, and these results were supported by reverse transcriptase polymerase chain reaction analysis using human OPN-specific oligonucleotides. Cells located away from the calcified area did not express OPN. The present findings indicate the involvement of OPN in the process of calcification of rotator cuff tendons and suggest that OPN plays a role in such painful disorders through the actions of at least two cell types.

Scapulohumeral rhythm : relationship between motion velocity and rhythm

The relative contributions of scapulothoracic and glenohumeral motion at different rates of shoulder motion were studied through adduction to abduction in the scapular plane. Nineteen shoulders of 10 healthy individuals (all men, 24–30 years of age) were analyzed using an image intensifier and a high-resolution digital video system. High- and low-speed motion consisted of 2 and 4 seconds per one cycle, respectively, from abduction to adduction in the scapular plane. Glenohumeral and scapulothoracic ratios were fixed at low speed and these results agree with the finding of other researchers. Ratios at high speed were not fixed and differed significantly from those at low speed. Ratios were high at the beginning of abduction or adduction and at angles beyond 40° abduction, then decreased according to the arm movement. Glenohumeral motion at high speed was more dominant at the beginning of abduction or adduction beyond the setting phase, then became less dominant according to the arm movement, compared with the motion at low speed.