Effects of tibial components on load transfer in the upper tibia.

Knee specimens were loaded in combinations of compression, anteroposterior force, rotational torque, and varus-valgus moment. The strains on the outer surface of the tibia at four levels were determined from strain gauges. Tibial components of the central peg type were cemented in place and the strains again measured for the same loading combinations, thus obtaining comparisons with the normal.

The kinematic rotating hinge: biomechanics and clinical application.

The Kinematic rotating hinge offers a solution as a salvage procedure for severely deformed and unstable "end-stage" knees. Excellent short-term results in terms of pain relief can be achieved, and motion up to 130 degrees is possible, depending on the condition of the quadriceps mechanism and the extent of scarring from previous operations. Care must be taken to avoid cortical penetration, especially in cases of hinge revisions, osteoporosis, thin-walled bones, and the presence of old cement.

Jejunal glucose absorption in selected high and low weight lines of domestic fowl.

Intestinal glucose uptake was measured in normal and dwarf chickens from lines selected fro high and low body weight. Jejunal tissue rings were excised from 9-week-old chicks and incubated in a medium containing .002 M glucose.

Fixation of tibial components of knee prostheses.

Twelve different tibial components were compared for fixation. The components included compartmental, anteriorly joined, posterior-cruciate retaining, and one-place with one, two, or three fixation posts; all-plastic or with a metal tray. The apparatus applied compressive load with anterior-posterior force, rotational torque, or varus-valgus moment.

Forces at the glenohumeral joint in abduction.

The purpose of this study was to determine the forces in the glenohumeral joint for isometric abduction (including all directions of rotation) in the plane of the scapula. The lines of actions of muscles were obtained from 3 upper quarter specimens, electromyographic data was used, as well as geometrical parameters of shoulder motion. The main assumption made in the analysis was that the force in a muscle was proportional to its area times the integrated electromyographic signal.

An apparatus to assess function of the hand.

An apparatus was developed to study the movement, strength, and manipulative ability of the hand. To obtain normal values, measurements were made on 80 women and 65 men between the ages of 17 and 70 years. As a comparison, 30 female patients with severe rheumatoid arthritis were studied.

Excision of the cruciate ligaments in total knee replacement.

The cruciate ligaments (and the intercondylar eminence of the tibia) should be removed when the knee is replaced. A mechanically unlinked prosthesis can be designed which will then be capable of restoring "cruciate" stability, i.e.

Conformity in condylar replacement knee prosthesis.

Experiments were carried out to determine the optimum conformity between the femoral and tibial condyles in condylar replacement knee prostheses. Wear tests and observations from removed prostheses indicated that both high and low conformity produced characteristic abrasion and fatigue. Partly conforming condyles provided stability under load-bearing but allowed laxity to occur.

Ligament length patterns, strength, and rotational axes of the knee joint.

Using intact fresh specimens, the cruciate ligament lengths for positions of flexion and internal-external rotation were computed using a non-invasive technique; using photographic methods, the centers of transverse rotation on the tibia and the direction of the flexion axis were also obtained. The anterior cruciate was found to be particularly effective in restraining internal tibial rotation; the ability of the posterior cruciate to restrain external rotation, however, depended strongly on the transverse axis location. Ligament length changes during flexion were found to be small in the absence of rotary torque and anteroposterior forces.

Normal and abnormal motion of the shoulder.

The roentgenographic parameters of motion in normal and abnormal shoulders, including the movement of the scapula, arm angle, glenohumeral angle, scapulothoracic angle, excursion of the humeral head, and instant center of motion for abduction in the plane of the scapula, were determined in twelve normal subjects and fifteen patients. The scapula rotated externally with abduction. The ratio of glenohumeral to scapulothoracic movement was 5:4 after about 30 degrees of abduction.

Stabilizing mechanisms of the loaded and unloaded knee joint.

Knee specimens were placed in an apparatus which imposed cyclic anterior-posterior or rotatory forces, with various compressive loads applied to the joint. Force-displacement graphs or torque-rotation graphs were automatically plotted, giving the laxity under various conditions. The ligaments, capsule, and menisci provided joint stability under no-load conditions.

[Arthroplasty of the knee. Prosthesis without uni- or bicondylar hinge].

The prosthesis has two components. The femoral component is metallic surfacing the condyle and a tibial plateau in polyethylene replaces the original one. The prosthesis can be uni or bi-condylar.

Laboratory evaluation of a metal-plastic type of metacarpophalangeal joint prosthesis.

In the normal joint, the conformity of the joint surfaces can provide appreciable dorsal-volar shear stability when a compressive joint force acts. The centers of rotation were within 3 mm of the center of the metacarpal ball. Passive radial-ulna motion at 0 degrees flexion was close to 60 degrees, active motion being half of this; at 90 degrees flexion, there was 37 degrees passive and 23 degrees active motion.

Kinematics of the knee after prosthetic replacements.

A method was developed for describing the flexion-extension motion of the knee joint in a sagittal plane, by employing ciné radiography and then plotting the loci of three points on the femur relative to the tibia. Normal knees displayed similar patterns, the curves were smooth, and flexion-extension curves superimposed. A standard knee outline with standard curves was defined, with which to compare the abnormal and prosthetic knees.