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Biomedical subjects

G M Gardner

Publications and source records attributed to G M Gardner.

At least 37 records · Page 2Linked to original sources

Shoulder-muscle strength and range of motion following surgical repair of full-thickness rotator-cuff tears.

Postoperative measurements of the range of motion and muscle strength of the shoulder and ratings of pain and the ability to perform daily activities were made in fifty-eight patients (sixty-three shoulders) who had a repair of a full-thickness rotator-cuff tear. Postoperatively, the patients had an average of 126 degrees of active flexion of the shoulder and an average of 130 degrees of active abduction. Passive motion averaged 21 degrees more than active motion. The strength of the abductor muscles of the shoulder averaged approximately 86 per cent of normal. Most patients reported marked relief of pain and rated themselves as having mild or no deficits in their ability to perform daily activities. The length of the cuff tear significantly affected the functional results. Short tears (less than 2.5 centimeters) were associated with greater strength and range of motion than were long tears. Fifteen of the nineteen patients who were unable to work preoperatively because of the shoulder returned to work after surgery, but not necessarily to the same type of work that they had done before the onset of the problem with the shoulder.

Acromion↗

Strength and range of motion in the ankle in two age groups of men and women.

Strength and range of motion of the ankle were measured in 20 normal men and 20 normal women divided equally into two age groups (25-35 and 50-60 years). Total range of dorsiflexion/plantar flexion averaged 75 degrees and the total range of inversion/eversion averaged 28 degrees. Few significant differences in range of motion were found between age groups, between men and women, or between dominant and nondominant limbs. Mean torque values for the men were greater than those for the women for all four muscle groups tested (plantar flexors, dorsiflexors, invertors and evertors). Strength of the women ranged from 62 to 70 percent of that of the men, depending upon muscle group. A multiple regression analysis showed that after the variability in muscle strength due to height and lean body weight had been taken into account, the additional variance accounted for by gender was very small. Differences in torque between age groups were not statistically significant. Differences in strength between dominant and nondominant limbs were significant only for the plantar flexors and dorsiflexors of the men.

Adult↗

Treadmill vs. floor walking: kinematics, electromyogram, and heart rate.

To identify the degree of difference between treadmill and floor walking, kinematic, electromyographic (EMG), and heart rate measurements were recorded in seven normal female subjects during walking at three speeds on the treadmill and on the floor. During treadmill walking, subjects tended to use a faster cadence and shorter stride length than during floor walking. In addition the displacements of the head, hip, and ankle in the sagittal plane showed statistically significant differences between floor and treadmill walking. Average EMG activity was usually greater on the treadmill than on the floor; however, this difference was only significant for the quadriceps. Heart rate was significantly higher during fast treadmill walking than floor walking. In general, treadmill walking was not found to differ markedly from floor walking in kinematic measurements or EMG patterns.

Adult↗

Hip function after total vs. surface replacement.

Kinesiologic measurements were made in two groups of 20 men before and 6 and 24 months after resurfacing or conventional replacement. Before surgery the group to have resurfacing was younger, had less pain, slightly more hip motion, greater muscle strength, walked faster, and used fewer assistive devices during walking than the group to have the conventional replacement. After surgery, the group with resurfacing maintained its advantage in muscle strength and walking velocity.

Age Factors↗

Functional performance after tibial rotationplasty.

We measured muscle strength, joint motion, and gait parameters and determined the electromyographic activities of the ankle and knee during walking, running, and stair-climbing in two children who had had a tibial rotationplasty for osteosarcoma of the distal end of the femur. Both had marked loss of strength in the plantar flexors on the side of the prosthesis compared with the sound side, although electromyographic recordings showed that the rotated calf muscles, to a substantial degree, had assumed the function of extensors of the prosthetic knee. Despite some abnormalities in gait, both children walked at speeds that were comparable to those of normal children. They could also run, climb stairs by stepping up with both limbs, and participate in many recreational activities. The functional abilities of these children suggested that rotationplasty, in patients with a similar lesion, is a worth-while alternative to above-the-knee amputation.

Artificial Limbs↗

Kinematic and EMG patterns during slow, free, and fast walking.

Kinematics and electromyographic (EMG) activity were recorded in seven normal women during walking at slow, free, and fast speeds. Speed-related differences were found in the stride dimensions, temporal components, and most of the simultaneous displacement patterns of body segments measured. For most of the muscles tested, the amplitude of normalized EMG activity decreased as walking speed decreased. The findings emphasize the importance of accounting for the effect of speed itself on measurements of gait.

Adult↗

Function after revision of failed total hip arthroplasty.

Measurements of functional performance were made before and 6 months after 31 primary total hip replacements and 31 total hip revisions for prosthetic loosening. After revision, functional performance returned to levels substantially the same as after primary hip replacement except for greater reliance on canes for patients in the revised group. Ratings of hip status and hip pain were slightly less satisfactory after revision as compared to after the primary operation.

Adult↗

Gait patterns in above-knee amputee patients: hydraulic swing control vs constant-friction knee components.

Multiple displacement patterns, stride dimensions, and temporal components during slow, free-speed, and fast walking were compared in the same seven above-knee amputees using prostheses with constant-friction knee components and using hydraulic swing-control knee components. During walking with the hydraulic-type prostheses, the amputees showed a wider range of walking speeds, improvement in the equality of the durations of successive swing and stance phases, and greater uniformity of forward progression. Improvements toward normal were also seen in several of the displacement patterns of the prosthetic limb during walking with the hydraulic knee. Several gait abnormalities persisted with both types of prostheses.

Adult↗

Anterolateral compared to posterior approach in total hip arthroplasty: differences in component positioning, hip strength, and hip motion.

In order to identify the functional advantages or disadvantages between the anterolateral and the posterior approaches to total hip arthroplasty, measurements of prosthetic position, hip-muscle strength, and hip joint mobility were made after Müller total hip arthroplasty without osteotomy in 52 patents operated through a posterior approach and 41 patients operated through an anterolateral approach. Men and women who had the posterior approach had less prosthetic component anteversion and longer neck lengths, with resultant more lateral and distal placement of the greater trochanter than groups with the anterolateral approach. Groups with the posterior approach had more normal hip abductor-muscle strength and more inward rotation on the operated side than group with the anterolateral approach. Groups with the anterolateral approach had more outward rotation on the operated side than groups with the posterior approach. These differences in function were related to the surgical approach rather than to differences in component position. An understanding of these observations should be used for selection of the surgical approach for the patient on an individual basis.

Biomechanical Phenomena↗

Comparison of Müller total hip replacement with and without trochanteric osteotomy. Kinesiologic measurements of 82 cases 2 years after surgery.

Function of 37 patients with osteotomy of the greater trochanter during total hip replacement (41 hips) is compared to function of 38 patients (41 hips) without osteotomy. Subjective assessments and cane force measurements were slightly more favorable in the group without osteotomy. Objective measurement of hip motion, hip abductor and adductor muscle strength, weight distribution during standing, and multiple components of free-speed and fast walking showed no statistically significant differences between performance of the groups with and without osteotomy before surgery or 6 months or 2 years after. This suggests that osteotomy provides no functional advantages to the patient beyond those obtained in total hip replacements without osteotomy.

Aged↗

Strength of isometric and isokinetic contractions: knee muscles of men aged 20 to 86.

Maximum isometric and isokinetic torques of the knee flexor and extensor muscles were measured at three knee joint positions in 72 normal, health men in three age groups from 20 to 86 years. The isokinetic contractions were performed at a speed of 36 degrees per second. The isometric contractions were sustained for five seconds. Strength of the men in the older age groups was significantly less than that of the youngest group. The strength of the isokinetic contractions was significantly less than that of the isometric contractions for all joint positions. The men in the oldest age group generally took longer than the younger men to reach peak torque during the isometric contractions. The torque values provide base-lines for evaluating patients with knee joint disabilities.

Adult↗

A comparison of the funtional performance of patients with Charnley and Müller total hip replacement. A two-year follow-up of eighty-nine cases.

Measurements of functional performance in 35 cases with Charnley total hip replacement were compared with those of 54 cases with Müller replacement before surgery and at 6- and 24-month follow-up intervals. The measurements included strength of the hip abductor and adductor muscles, hip motion, the amount of weight borne on the involved limb during standing posture, multiple components of free-speed and fast walking, and force applied to canes and crutches. Both replacement groups improved significantly in most components of function. In fact, both groups reached or nearly reached the lower limits of normal variability in weight-bearing ability, cadence, and some components which relate to smoothness of walking performance. The groups with Müller and Charnley replacement differed most in some components of range of hip motion, hip muscle strength, and lateral lurching during walking.

Adult↗

Function of the triceps surae during gait. Compensatory mechanisms for unilateral loss.

We studied the gait of a woman who was normal except for surgical excision of the gastrocnemius and soleus muscles. She was able to compensate for nearly all of her abnormalites of gait by excessive lateral pelvic tilt and prolonged quadriceps activity. Her mild disability, as regards gait, consisted of inability to increase walking speeds beyond the normal pacing. However, despite uneven step lengths, she had uniform forward progression. She had excessive dorsiflexion of the ankle and diminished plantar flexion on the involved side even though the retained plantar flexors could provide 38 per cent of her normal plantar flexor strength.

Adult↗

Walking patterns of men with parkinsonism.

Interrupted-light photography was used to record the simultaneous displacement patterns of multiple body segments of 44 patients with parkinsonism during free-speed and fast walking to quantitatively characterize their gait peculiarities. The patients were categorized into three disability groups according to their independence in activities of daily living. Their measurements of walking performance were compared to those of normal men. The gait components of the patients, which related systematically to the degree of disability, were: step lengths, vertical excursions of the head, extension of the hip and knee of the backward-directed limb at the onset of contralateral weight bearing, toe-floor distance at the onset of weight bearing, and rotation of the thorax.

Activities of Daily Living↗

Maximum isometric knee flexor and extensor muscle contractions: normal patterns of torque versus time.

Isometric torque of the knee flexor and extensor muscles were recorded for 5 seconds at three knee joint positions. The subjects included healthy men in age groups from 20 to 35 and 45 to 65 years of age. The amplitudes and duration of peak torque and the time to peak torque were measured for each contraction. Peak torque was usually maintaned less than 0.1 second and never longer than 0.9 second. At each of the three angles, the mean extensor muscle torque was higher than the mean flexor muscle torque in both age groups, and the mean torque for both muscle group was higher among the younger than among the older man. The highest average torque was recorded at the knee angle of 60 degrees for the extensor muscles and 45 degrees for the flexor muscles, but this was not always a stereotyped response either for a given individual or among individuals.

Adult↗

Roentgenographic measurements after Müller total hip replacement. Correlations among roentgenographic measurements and hip strength and mobility.

In fifty-two patients with Müller total hip replacement, roentgenographic measurements of prosthetic component positioning were correlated with hip-muscle strength and mobility measurements. Compared with the normal side, the average position of the center of the prosthetic head was more medial and superior in the pelvis, and the greater trochanter was more distal and lateral. Increasing neck length (distance from the center of the prosthetic head to the lesser trochanter) and a more distal position of the greater trochanter were among the measurements that related favorably to measurements of patient function. More superior placement of the center of the prosthetic head in the pelvis was associated with a more superior position of the lesser trochanter, which related adversely to function.

Aged↗