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Biomedical subjects

A E Flatt

Publications and source records attributed to A E Flatt.

At least 19 recordsLinked to original sources
PubMed1979

Biomechanical evaluation of metacarpophalangeal joint prosthesis designs.

A laboratory biomechanical analysis of metacarpophalangeal joint prosthesis designs was done with fresh cadaver finger rays. The center of rotation, range of motion, tendon excursion, and fingertip force were determined on the specimens before and after implanting Swanson, Niebauer, Steffee II, St. Georg-Buchholz, Schultz, and modified Strickland prostheses. Their biomechanical behavior varied considerably and none duplicated the normal metacarpophalangeal (MP) joint. Each has design characteristics that may be clinically advantageous as well as disadvantageous. Irrespective of the design, the studies done cannot be divorced from the following factors: (1) implant material properties--silicone rubber implants buckled with tendon loading; this deformity created a significant flexor mechanical advantage and an extensor mechanical disadvantage; (2) implant fixation--freely movable implant stems dampened part of the applied load; braided suture provided inadequate immediate fixation; (3) implantation technique--the articulated prostheses can be technically unforgiving; errors in technique resulted in alteration of their biomechanical behavior.

Biomechanical Phenomena↗
PubMed1979

A comparison of hand growth in elementary schoolchildren in Czechoslovakia and the United States.

Studies have been made of the growth patterns of hands of elementary schoolchildren in Czechoslovakia (1707 children) and in the United States (1641 children). This paper compares the results of these studies and summarizes the patterns of growth for both hands of boys and girls aged from five to 12 years. The results indicate that the United States children generally have shorter and wider hands than their Czech counterparts. In both countries, boys have wider hands than girls, although there is evidence that at ages 11 and 12 years the girls' hands are longer. Growth spurts in both width and length measurements are apparent in children's hands in both countries, but the spurt often occurs at an earlier age in Czech children. Awareness of these general patterns of hand growth should be of assistance to the hand surgeon.

Child↗
PubMed1979

Annular constricting bands.

We reviewed forty-five patients with congenital constriction bands with an average follow-up of 15.8 years. The family history and associated anomalies were recorded and particular attention was paid to temperature gradients and neurocirculatory deficits with respect to band location. No family history of band constrictions was elicited. Most of our patients were products of first pregnancies and of young mothers. Deformity of the nails was a constant finding in patients with distally located bands. All patients demonstrated at least one other anomaly, most commonly a malformation of the hand. Neural deficits were noted in 23 per cent of the patients, while circulatory findings appeared in 16 per cent. A significant temperature gradient averaging 2.38 degrees Celsius was noted in twenty patients in whom the bands were located proximally. All patients with neural deficits demonstrated a significant temperature gradient. Staged z-plasty was the procedure of choice in surgical release of constriction bands.

Abnormalities, Multiple↗
PubMed1978

Clinical and experimental studies on the effect of extensor carpi radialis longus transfer in the rheumatoid hand.

Digital ulnar drift in the rheumatoid hand is a complex problem. The radial deformity of the wrist causes abnormal forces on the extrinsic flexor and extensor tendons which aggravate metacarpophalangeal ulnar drift. Analysis of the results of the transfer of the extensor carpi radialis longus to the extensor carpi ulnaris in 20 wrists showed that 13 of 20 had significant correction of the wrist deformity. The transferred tendon did not contract during active ulnar deviation. Laboratory studies of the transfer on cadaveric rheumatoid wrist models showed correction of the wrist deformity. The dorsal ulnar capsule was determined to be a stabilizer of wrist position, as evidenced by deformity after transection.

Arthritis, Rheumatoid↗
PubMed1978

Kinematics of the wrist. I. An experimental study of radial-ulnar deviation and flexion-extension.

The kinematics of the wrist during radial-ulnar deviation and flexion-extension were studied in several ways. In six fresh cadaver wrists, the forearm was fixed in full pronation, each motion was constrained to one plane, and two metal markers were placed in each of the finger metacarpals, as well as in the radius and all of the carpal bones except the pisiform and greater multangular. Radial ulnar and flexion-extension movements in these wrists were studied roentgenographically. In the wrists of six normal volunteers, a similar roentgenographic analysis was carried out and the trajectories of wrist motions also were studied using light-emitting diodes. Finally, roentgenographic measurements were made on 100 wrists of normal subjects. From these studies, it was concluded that: (1) during each of these motions, rotation occurs about a fixed axis located within the head of the capitate, and the location of each axis is not changed by the position of the hand in either plane; (2) the distance from the base of the third metacarpal to the distal articular surface of the radius (the carpal height), measured along the proximally projected axis of the third metacarpal on posteroanterior roentgenograms, is constant throughout radial-ulnar deviation of the normal wrist and can be used as a measure of carpal collapse; and (3) the perpendicular distance of the fixed axis of rotation for radial-ulnar deviation from the distally projected longitudinal axis of the ulna can be used as a quantitative measurement of the amount of translation of the carpus in pathological conditions.

Biomechanical Phenomena↗
PubMed1978

Kinematics of the wrist. II. Clinical applications.

A reproducible method of measuring carpal height and carpal-ulnar distance and expressing them as ratios of these distances to the length of the third metacarpal, as reported in a previous paper9, was applied to serial roentgenograms of seventeen patients with rheumatoid disease and six patients with Kienböck's disease. These ratios provide an accurate expression of the extent of carpal collapse and of ulnar translation. However, once carpal collapse has occurred, the trajectory of hand motion becomes flattened, and, as a result, the carpal height ratio will vary as the wrist moves from maximum radial to maximum ulnar deviation. These ratios may be of use in predicting a patient's clinical course, but a larger clinical study is necessary before use of the measurements for this purpose can be recommended with assurance.

Anthropometry↗
PubMed1978

Dysplasia epiphysealis hemimelica of the ulna.

A 3-year-old boy developed an abnormality of the forearm and wrist characterized by asymmetrical overgrowth, premature ossification of the distal ulnar epiphysis, shortening of both bones of the forearm, dorsal bowing of the ulna and formation of an enlarged lunate from 2 ossification centers. The eccentric overgrowth of the distal ulnar epiphysis was similar to the abnormality seen in dysplasia epiphysealis hemimelica of the long bones of the lower limbs, tarsal and carpal bones.

Child, Preschool↗
PubMed1978

An accurate data collection method for spatial motion using a sonic digitizer.

An accurate collecting method for spatial displacement data utilizing a sonic digitizer which works electronically and acoustically is described. The sequence of the operation of the digitizer system is explained. As an application, the study of elbow flexion-extension is presented. Finally, operational precautions for using this system are discussed.

Biomechanical Phenomena↗
PubMed1977

Congenital triangular bones in the hand.

From the literature we found reports of 105 patients whom we judged had a triangular deformity of one of the bones of the hand or foot. We found 49 patients of our own with 84 delta-shaped phalanges limited strictly to the hand. This represents an incidence of 3.5% of our congenital abnormalities of the upper extremity. The deformity is associated with many abnormalities: syndactyly, polydactyly, symphalangism, triphalangeal thumb, cleft hand, and hypoplastic hand are the most frequent Triangular deformity of the bone of the index finger usually is associated with Apert's syndrome. Triangular deformity of the proximal phalanx of the ring finger often is found with central polydactyly. Our average follow-up time on these 49 patients was 14 years, giving us a chance to establish some guidelines and general rules about the natural history and treatment of the delta bone.

Abnormalities, Multiple↗
PubMed1977

Camptodactyly: an analysis of sixty-six patients and twenty-four operations.

Camptodactyly is a nontraumatic flexion deformity of the proximal interphalangeal joint. The literature pertaining to its etiology and treatment is reviewed. An analysis of 66 patients with 110 affected hands is discussed with particular reference to the natural history of this deformity and the results of 24 operative procedures. Improvement was noted in less than 20% of 32 patients treated nonoperatively and followed for an average of 30 months. Corrective types of operative procedures in 20 hands resulted in improvement in only 35%. A treatment plan dependent on the age of the patient, the presence or absence of osteocartilagenous changes at the proximal interphalangeal joint, and associated anatomic abnormalities is presented.

Contracture↗
PubMed1976

Poland's syndrome.

Forty-three consecutive cases of Poland's syndrome were analyzed and the relevant literature was reviewed. The syndrome is not hereditary and is of unknown origin. It affects males more frequently than females. The clinical features are variable but always include congenital aplasia and syndactyly. The middle phalanges are hypoplastic or absent so that effectively there is only one interphalangeal joint. The syndactyly is usually incomplete and simple. It may involve all fingers and frequently includes the thumb, which then lies in the same plane as the fingers. Poland's syndrome may also include hypoplasia of the nipple and breast, hypoplasia of the upper ribs, herniation of the lung, contracture of the anterior axillary web, and elevated scapula. The arm and more frequently the forearm are hypoplastic. The right side is more often affected than the left. Surgical treatment by separating the syndactyly is recommended. In some cases a digit is removed to produce a three-fingered hand. Surgery is initiated by the age of one year and is completed by the time the child enters school, although periodic revisions may be necessary. Although the hand remains hypoplastic and functional capacity is limited by the inherent skeletal anomalies, surgical treatment improves functional capacity and cosmetic appearance in the majority of patients.

Arm↗
PubMed1976

Evaluation of the two-stage flexor-tendon reconstruction in severely damaged digits.

From July 1971 to July 1974, the two-stage tendon-grafting procedure of Hunter and Salisbury was performed in thirty-two severely damaged digits in twenty-five patients. Of these digits, twenty-three fingers and five thumbs could be evaluated for gain in total active flexion (expressed as per cent of preoperative passive flexion) and for gain in total active motion (expressed as per cent of total preoperative passive motion) after follow-ups ranging from six to fifty months. The results for total active flexion were 60.9 per cent good, 21.7 per cent fair, and 17.4 per cent poor, and for total active motion 21.7 per cent good, 56.5 per cent fair, and 21.7 per cent poor. Complications were frequent after both stages and included infection, migration of the rod, and adhesions within the proximal end of the newly formed sheath. Flexion contractures were a significant problem.

Adolescent↗