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Biomedical subjects

M P Murray

Publications and source records attributed to M P Murray.

At least 19 recordsLinked to original sources

Census adjustment and the distribution of federal spending.

In 1989, programs that use population counts to determine the distribution of their funds transferred $236 per capita to state and local governments. If the 1990 census were adjusted to reflect undercounting, about 40% of state and local governments would receive increased grants averaging $56 per miscounted person; other jurisdictions would lose an almost equal amount of grant money. The surprisingly small reallocations arise because 1) total funds allocated by population are essentially fixed; 2) allocations depend on other factors in addition to population; and 3) programs vary as to whether they allocate funds in direct or inverse proportion to population.

Community Health Services

Function following partial fibulectomy.

The fibula is a valuable source of a bone graft, but because the fibula has a role in lower extremity function, it is important to determine whether partial removal results in dysfunction or other problems. Forty-one patients (48 +/- 10 years of age) had a portion of their fibula removed for a bone graft. At evaluation 27 +/- 8 months later, 24 had no pain, 11 mild pain, and six moderate or severe pain. Sixteen had no complaints of any kind, but four without pain had minor difficulties with vigorous activities, and three complained of ankle swelling. There were no differences in range of motion between the operated and nonoperated side. Average muscle torque was lower on the operated than on the nonoperated side, but this difference was statistically significant only for ankle evertors in men. This study demonstrates that most patients will have subjective complaints and mild muscular weakness after removal of a portion of the fibula.

Adult

Roentgenographic findings following anterior cervical fusion.

We reviewed the pre- and postoperative lateral cervical roentgenograms in 90 patients who had anterior fusions and compared their findings with age and sex-matched people without neck problems. The average interval from surgery to review was 5 years. Preoperatively, all patients had a higher incidence of degenerative spondylosis at the levels to be fused than their asymptomatic counterparts. Postoperatively, there was no difference in the incidence of degenerative change between the operated and the control group at the levels above and below the fusion with the exception of anterior osteophyte formation which was more frequent in those with fusions.

Cervical Vertebrae

Correlations between objective measures of function and a clinical knee rating scale following total knee replacement.

Few objective measurements of function, other than range of motion, have been reported for patients with total condylar knee replacement. Moreover, to our knowledge, no studies have been reported which assess the degree of relationship between clinical ratings and measurements of function in these patients. Kinesiologic tests of function and the Hospital for Special Surgery (HSS) Knee Rating Form were used to evaluate 34 patients before and 2 years after 39 total condylar knee replacements. Prosthetic alignment was also evaluated postoperatively. The kinesiologic studies showed postoperative improvement in muscle strength, weight-bearing ability, and use of assistive devices, and in velocity, knee flexion-extension, and lateral head motion during walking. A moderate but significant degree of improvement was measured by the HSS score. Correlation coefficients showed that the postoperative knee rating score was significantly related to almost all of the postoperative objective measurements of function. Correlation coefficients between the prosthetic alignment scores and measurements of function were not statistically significant. The study strengthens the validity of use of the HSS Knee Rating Form as a tool for evaluating functional performance, particularly during the postoperative period.

Aged

Comparison of function two years after revision of failed total hip arthroplasty and primary hip arthroplasty.

Because of the known high complication rate, it is important for both the patient and physician to know as much as possible about the outcome of revision operations for loosened total hip arthroplasties. This study evaluates the changes in subjective ratings and objective kinesiologic measurements from before revision operations through two years after revision operations. The object is to compare these measurements with the measurements of a group of patients with primary replacements. Both groups of patients showed significant improvement in most parameters from before to after surgery. These parameters included walking performance, hip muscle strength, range of motion, forces applied to canes, and the amount of weight borne on the operated limb during quiet standing. Compared to the control group with primary replacements, the group with revision used more assistive devices, had less pain relief, walked slower, had less hip motion, and had more lateral lurch. While results after revision surgery were not as gratifying as those after primary hip replacement, patients requiring revision can still anticipate substantial improvement.

Adult

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

Age-related differences in knee muscle strength in normal women.

This study provides normal baselines of knee muscle strength for women up to 86 years of age. Knee muscle strength (torque) was measured during maximum isometric and dynamic (isokinetic) contractions in 72 normal healthy women in three age groups between 20 and 86 years. Strength of the oldest group ranged from 56 to 78% of that in the youngest group, depending on knee joint position. Strength values were greater for isometric contractions than for isokinetic contractions (performed at 36 degrees per second) and were approximately twice as great for the extensor as for the flexor muscles. For both muscle groups, the torque generated with the knee in 30 degrees of flexion was usually lower than that generated with the knee at the 45- or 60-degree position. Despite the significant deficit found in the strength of the oldest group, it is likely that this relative weakness would not be detected on routine clinical examination using manual muscle testing.

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

Antalgic maneuvers during walking in men with unilateral knee disability.

The gait of men with unilateral knee disability has not been quantified previously. Interrupted-light photography was used to quantify the gait abnormalities of 35 men whose major disability was unilateral knee pain. The following antalgic maneuvers were found to be common to the gait of these patients: slow and uneven forward progression with lateral lurching toward the painful side, asymmetry in stride and temporal components, and abnormalities in the displacement patterns of most body segments. Subnormal knee motion was found during the stance and swing phases. Because treatment of patients with knee problems is usually directed toward pain relief, an understanding of how pain affects walking performance is important to the clinician when assessing a patient's problem.

Adult

Mutagenic activity of epoxy embedding reagents employed in electron microscopy.

Components of epoxy-based embedding media used in electron microscopy were examined for their mutagenicity in the Ames Salmonella system. The compounds, singly and in combination, were shown to be active with strain TA100 (base substitution indicator) but not with TA98 (frameshift indicator). When tested separately the epoxy resins Araldite, Epon, and vinyl cyclohexen dioxide (VCD) and the plasticizer diglycidyl ether of propylene glycol (DER-736) were found to be significantly mutagenic. These active compounds, in combination with liver mixed oxidase preparation (S9), showed increased mutagenicity over similar preparations in the absence of microsomal activation.

Epoxy Resins

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

Locomotion assistance through cane impulse.

The extent of locomotion assistance gained through cane usage by those with hip disorders is assayed. Employing as a standard the propulsive impulse delivered by each lower limb of a healthy young male, the cane is shown to supply about one-fifth the equivalent impulse, aside from other possible benefits. Full test values are given for nine handicapped subjects.

Adult