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Biomedical subjects

T D Cooke

Publications and source records attributed to T D Cooke.

At least 55 records · Page 3Linked to original sources
PubMed1988

Standardized biomechanical measurement for varus-valgus stiffness and rotation in normal knees.

Seventeen female and 24 male subjects had varus and valgus and apparent rotations measured using a standardized mechanical testing device that cyclically applied a 20-Nm moment in each direction. Five parameters--apparent varus rotation, apparent valgus rotation, apparent overall rotation, varus stiffness, and valgus stiffness showed intersubject variations approaching 40%. Right-left variations in the same subject averaged 12%, with no significant right-left differences overall. Female knees rotated 66% more than male knees and were 35% less stiff. The ratio of apparent valgus rotation to apparent varus rotation averaged 0.775, and the ratio of valgus stiffness to varus stiffness averaged 1.23 for all knees. Stiffness and rotation parameters were highly correlated for both genders in the valgus phase of testing. Results suggest that although magnitudes of measured parameters vary considerably from subject to subject, common relationships between parameters from the same normal knee exist.

Adult↗
PubMed1988

Geometry of the first metatarsophalangeal joint.

This study aimed to define the articular geometry of the metatarsophalangeal (MTP) joint of the great toe. Embedded in resin blocks, five pairs of cadaveric first MTP joints (all from men) were sequentially cut in the sagittal plane with a milling machine, removing 0.5 mm of bone in each cut. The photographed cartilaginous outline of each cut was digitized against reference markers, which enabled a computer system to superimpose each outline in three dimensions. The intersesamoidal ridge was found to be parallel to the lateral shaft. The peak of the ridge was just lateral to the midline of the MT head. The articular outline, through the ridge of each sample, was circular; however, other surface contours were noncircular. The undulating plantar aspect of the MTP head formed by the intersesamoidal ridge and related grooves was found to have symmetric relationships to the sesamoid bones and a consistent orientation to the shaft. The rounded distal dorsal aspect of the MTP head showed consistent differences to the concavity formed by the phalangeal base. The sample size is too small for the sizing of prostheses but it is adequate to study the geometry of the MTP joint. More data are needed for the accurate replication of a resurfacing prosthesis and understanding of joint kinematics.

Cartilage, Articular↗
PubMed1988

Geometry of the humeroulnar joint.

Clinical results with elbow prostheses have been disappointing. A detailed knowledge of elbow joint geometry and mechanics is necessary to improve prosthetic design. In this study, the humeroulnar articulation of four human cadaver elbows was examined using surface analytic methods. In this article, the location of the transverse axis of elbow flexion-extension is suggested in relation to well-defined landmarks, the medial and lateral epicondyles, and subsequently to the line connecting their most lateral points--the transepicondylar line. The geometry of the structures responsible for the carrying angle is discussed, as is the extent of cartilage-covered bearing areas of the lower humerus and upper ulna. Implications pertaining to prosthetic design and surgical technique resulting from this study are discussed.

Cartilage, Articular↗
PubMed1988

Antigen-induced tenosynovitis in hypersensitized rabbits: a model for rheumatoid tenosynovitis.

Rabbits were first immunized and later challenged with the same antigen (bovine serum albumin, or ferritin) by injection into the tibialis anterior tendon. Inflammatory changes of the tenosynovium and epitenon included infiltration by neutrophils (early) and mononuclear cells (later) over a 6-week course of tenosynovitis. A pattern of antigen entrapment in the tendon together with immunoglobulin was shown by use of radiolabelled antigen and immunochemical staining. Half-life of antigen in the tissues averaged 5 days over the 6-week period. Changes in the epitenon included cellular necrosis, appearance of phagocytic cells, and disruption of the collagen matrix. Tissues of control animals (challenged without prior immunization) showed minimal changes and significantly less retention of antigen (P greater than 0.005). The model is relevant to the mechanism of tendon damage associated with antigen-driven chronic inflammation, as may be the case in rheumatoid arthritis.

Animals↗
PubMed1988

Distribution of bone strength in the proximal tibia.

Indentation tests were used to determine the ultimate strength of the proximal tibia. Measurements were made at the subchondral bone surface and on transverse planes up to 25 mm below the surface. Medial condyles were stronger than lateral condyles, and in both cases bone strength decreased abruptly with distance from the surface, especially over the first 5 mm. The mean bone strength was greater in men than in women in both condyles, especially in the harder upper layers. The areas of greatest strength on both the medial and lateral sides varied with depth. At the surface, maximum strength in the medial region was more posterior in men than in women. With increasing depth, the area shifted medially in the medial region and laterally in the lateral region. Spatial distribution of strength across planes of the tibia seems consistent with anticipated patterns of load distribution in weight bearing and with the contiguity of the trabecular bone. The data are relevant to an understanding of normal joint mechanics and to the design and placement of prostheses in total knee arthroplasty.

Aged↗
PubMed1988

An electron microscopic study of early pathology in chondromalacia of the patella.

For a study of the ultrastructural pathology of chondromalacia patellae, we studied biopsy specimens that had been obtained at operation in twelve young patients who had pain in the anterior aspect of the knee due to mechanical derangement and also had the pathological changes in articular cartilage that are characteristic of chondromalacia. The initial pathological finding was swelling of the superficial matrix associated with breakdown of the collagen fiber network, especially at matrix streaks in the superficial and transitional zones. Fibrillated cartilage contained surface fissures that penetrated the middle layers. Amorphous electron-dense material was found covering the internal surfaces of the fissures; this appeared to contain degraded components of the matrix. In association with these changes, there were formation of nests of cells (clusters of chondrocytes) and increased numbers of organelles in the chondrocytes. A limited repair reaction also was observed in some specimens; this was characterized by the migration of fibroblast-like cells over the surface of the cartilage. The ultrastructural observations on these specimens from patients who had chondromalacia were compatible with a pathogenesis resulting from mechanical overload.

Adolescent↗
PubMed1987

Radiographic assessment of progression in osteoarthritis.

We evaluated methods of grading radiologic progression of osteoarthritis (OA). Sets of radiographs were assessed separately by 8 readers who were blinded to the time sequence. Included were radiographs of patients with OA of the hands (24 pairs), hips (40 pairs), and knees (32 pairs). Most films were taken 12-60 months apart. The relative contribution of individual joints (such as particular interphalangeal joints), of observations (such as narrowing or spurs), and of a single joint compartment (such as the medial or lateral compartment of the knee) toward evidence of OA progression was evaluated, as well as the reliability and concordance of scoring, and the sensitivity in detecting change. In assessing OA of the hand, the greatest sensitivity was achieved by reading a single posteroanterior bilateral hand radiograph for narrowing, spurs, and erosions, and scoring 10 joints (second and third distal interphalangeal, second and third proximal interphalangeal, and trapeziometacarpal joints, bilaterally), using a scale of 0-3. In OA of the hip, a single anteroposterior radiograph assessed for joint space narrowing and cyst formation yielded the greatest sensitivity. In OA of the knee, an anteroposterior radiograph, with weight-bearing, assessed for narrowing, spurs, and sclerosis in both the medial and lateral compartments yielded the greatest sensitivity. These techniques will be useful to the investigator in designing experimental studies and to the clinician in determining the rate of disease progression in an individual patient.

Aged↗
PubMed1987

Femoral anteversion: assessment based on function axes.

This study describes a clinically oriented anatomical assessment of anteversion on 32 cadavers ranging from 61 to 89 years. The method used a three-dimensional reference system based on functional axes of the femur. Each soft tissue-free femur was mounted on an osteometric table and aligned to its functional axes. The long axes were defined as passing from the centre of the femoral head to the femoral attachment of the posterior cruciate ligament (PCL). A line that ran through the PCL attachment (equal distal origin of this system) and was parallel to a transepicondylar line served as transverse axis. Anteversion of the femur was defined as an angle formed to the transverse axis by a line running through the centre of the femoral head through the midpoint of the narrowest segment of the femoral neck. The measurement mean for anteversion among these specimens was 7.4 degrees with a range from -10.8 degrees (retroversion) to 22.1 degrees. There was no statistical difference in mean values (p less than 0.05) between sexes or between right and left sides of the group; however, there were large variations for anteversions when each side in the same individual was compared (although there was no dominant side). Retroversions were observed in four of 32 femurs (12.5%). No correlation was found between the anteversion in these femurs and rotational geometry at the knee. We compared our data with those obtained by conventional techniques, by which anteversion for each femur was measured after the bone had been placed on a flat surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Orthopedic sawblades. A case study.

Surgical stainless steel sawblades are frequently used with metal templates at implant surgery, hence there is a high potential for blade damage and suboptimal bone cuts. The authors appraised currently used operating room sawblades with a comparison of their cutting efficacy. There were numerous instances of damage to the cutting teeth surfaces. At a controlled cutting speed, such blades require significantly greater force than unused blades to cut cancellous and cortical samples of bovine bone. Microscopic assessment of cancellous bone specimens cut with damaged blades revealed torn, irregular, debris-filled surfaces. Blades should be inspected for damage after each use and discarded if their condition is in doubt.

Bone and Bones↗
PubMed1987

The anatomy and functional axes of the femur.

Linear and angular measurements were made on thirty-two cadaveric femora with respect to the mechanical (functional) axes of the bone. The long axis was defined as a line from the center of the femoral head to the anterolateral attachment of the posterior cruciate ligament. The transverse axis was defined as a line through the posterior cruciate ligament parallel to the line connecting each epicondyle. The condylar width, the length of each interepicondylar line, correlated well with depth, but the projections of the condyles from the transverse plane revealed significant variations from specimen to specimen. Considerable variation also was found between femora in terms of angular dimensions (that is, the angle of anteversion and the neck-shaft angle proximally, and the valgus angle of the femoral shaft distally). Considerable interspecimen variation in the angles between the transcondylar plane and the femoral center, in accord with the valgus angle of the femoral shaft distally, was also noted. The mean transcondylar valgus angle (described as the tangent of the condyles to the perpendicular of the long axis) was 3.8 degrees. In contrast, little variation among specimens was noted for the angle made by the shaft and the long axis.

Aged↗
PubMed1987

Significance of immune complex deposits in osteoarthritic cartilage.

Deposits of immunoglobulins and complement in cartilage with synovial mononuclear cell infiltrates suggest local immune reactions in osteoarthritic joints. The variabilities defined in deposition pattern and synovial histopathology, the patterns and extent of polyarthritis, without evidence of systemic illness, suggest that these immune reactions mark past events in the host's response localized in mechanically prejudiced articulations. The current data give little support for an immune initiation for osteoarthritis nor for the induction of autoimmunity; rather, they suggest episodes of immune insult which may at times initiate and at times prolong clinical inflammation in mechanically deranged sites and which, via the activation of complement and mononuclear cell mediators, accelerate cartilage damage.

Antigen-Antibody Complex↗
PubMed1986

Development of criteria for the classification and reporting of osteoarthritis. Classification of osteoarthritis of the knee. Diagnostic and Therapeutic Criteria Committee of the American Rheumatism Association.

For the purposes of classification, it should be specified whether osteoarthritis (OA) of the knee is of unknown origin (idiopathic, primary) or is related to a known medical condition or event (secondary). Clinical criteria for the classification of idiopathic OA of the knee were developed through a multicenter study group. Comparison diagnoses included rheumatoid arthritis and other painful conditions of the knee, exclusive of referred or para-articular pain. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop sets of criteria that serve different investigative purposes. In contrast to prior criteria, these proposed criteria utilize classification trees, or algorithms.

Adult↗
PubMed1986

A three-dimensional finite element analysis of the upper tibia.

A three-dimensional finite element model of the proximal tibia has been developed to provide a base line for further modeling of prosthetic resurfaced tibiae. The geometry for the model was developed by digitizing coronal and transverse sections made with the milling machine, from one fresh tibia of average size. The load is equally distributed between the medial and lateral compartments over contact areas that were reported in the literature. An indentation test has been used to measure the stiffness and the ultimate strength of cancellous bone in four cadaver tibiae. These values provided the statistical basis for characterising the inhomogeneous distribution of the cancellous bone properties in the proximal tibia. All materials in the model were assumed to be linearly elastic and isotropic. Mechanical properties for the cortical bone and cartilage have been taken from the literature. Results have been compared with strain gage tests and with a two-dimensional axisymmetric finite element model both from the literature. Qualitative comparison between trabecular alignment, and the direction of the principal compressive stresses in the cancellous bone, showed a good relationship. Maximum stresses in the cancellous bone and cortical bone, under a load which occurs near stance phase during normal gait, show safety factors of approximately eight and twelve, respectively. The load sharing between the cancellous bone and the cortical bone has been plotted for the first 40 mm distally from the tibial eminence.

Aged↗
PubMed1986

Scanning electron microscopy of antigen induced arthritic joints. I. Inflammatory cell interactions at synovial-meniscal surfaces during the Arthus response.

Scanning electron microscopy has been used to study experimental antigen induced arthritis, providing a unique perspective of the early inflammatory events. An initial aggregation of acute inflammatory cells was noted at the synovial-meniscal junction with maximal numbers observed between 12 and 24 h post challenge. Variations in cell surface ruffling, which may represent different phases of activation, were observed throughout the Arthus response. By 48 h post challenge the meniscal and synovial surfaces were covered by a mat of fibrin and degraded cell remnants.

Animals↗
PubMed1986

Deleterious interactions of immune complexes with tibial cartilage of antigen-induced arthritic rabbits. II: Chondrocyte degradation.

The observations of immune complex (IC) deposition in the surface of rheumatoid arthritis (RA) cartilage, in conjunction with degradative changes in superficial and midzone chondrocytes, raised the question of causal relationships. In antigen-induced arthritis in rabbits, cartilage degradation occurred in association with IC deposition and is accompanied by chondrocyte damage. Superficial and midzone chondrocytes in rabbit tibial cartilage of arthritic joints, induced by bovine serum albumin (BSA) or ferritin (Fn), were examined by electron microscopy during the evolution of the arthus response. The first cell changes were noted at six hours, by which time superficially formed IC had begun to extend into the matrix. Elongated cytoplasmic footlets, numerous lysosomes, and lipid droplets occurred initially. By 24 hours, concomitant with the deeper extension of surface IC, prominent changes in chondrocytes of both superficial, and midzones progressed to ultrastructural evidence of cell death. The pinocytosis of electron-dense amorphous materials, which included IC, preceded degradation. These data suggest that the observed cytopathology is a manifestation of locally deposited IC.

Animals↗
PubMed1986

A scientific basis for surgery in rheumatoid arthritis.

Understanding a disease process provides the scientific basis for specific treatment. In rheumatoid arthritis (RA), disease(s) of unknown cause, the lack of knowledge about the intrinsic involvement of the articular collagenous tissues (ACT) as a site for the deposition and persistence of immune complexes may have led to poor long-term results of surgery, especially synovectomy. Because we may now presume that immune complexes in ACT provide inflammatory, immune foci for chronic synovitis, ablative surgery of the damaged cartilaginous tissues is a specific remedy. Such knowledge may be used judiciously with techniques of fusion, resection, and arthroplasty to improve and maintain the long-term function of patients with the crippling seropositive form of the disease.

Arthritis, Rheumatoid↗