Biomedical subjects

R K Laughman

Publications and source records attributed to R K Laughman.

9 recordsLinked to original sources

PubMed1984

Functional evaluation of total knee replacement.

The assessment of patients following prosthetic knee replacement suffers from a lack of objective criteria. An automated method of laboratory assessment that permits the objective evaluation of knee joint function is described. Nine biomechanical parameters were statistically selected, weighted, and combined to develop a Performance Index (Ip). One hundred ninety-two patients (274 diseased knees) were studied prior to total knee replacement surgery, with 107 patients (138 knees) returning for a 1-year postoperative study. Preoperative rheumatoid knees were found to have significantly poorer function than those involved with degenerative disease. Overall, the patients experienced a marked improvement 1 year post-total knee replacement (TKR), with their functional scores approaching the lower limits of normal. Prostheses were assessed according to generic classes as well as specific design types. The newer generation devices were found to produce better functional results. In the patients receiving Anametric and Total Condylar total knee devices, a patellar resurfacing component was found to produce improved knee function in comparison with patients receiving the same prosthesis but without patellar resurfacing.

Adult↗

PubMed1984

Objective clinical evaluation of function. Gait analysis.

Automated gait analysis allows us to document and quantify objectively normal gait, functional deficits, and patient response to therapeutic intervention. Instrumentation for this analysis at the Mayo Clinic Gait Laboratory includes three-dimensional electrogoniometers for measurement of relative joint rotation at the hip, knee, and ankle; footswitches that record foot-floor contact sequences; instrumented mats that measure step length and width; piezoelectric force plates for measurement of floor reaction forces; and two walkways that simulate a variety of ground conditions. We use a DEC-PDP 11/34 computer for acquisition, storage, and analysis of data and for generation of a gait report form that displays a patient's results relative to normal and previous evaluations. Applications of these techniques include assessment of function preoperative and postoperative total joint arthroplasty, quantification of gait faults, and documentation of effectiveness of exercise and gait training techniques. We have demonstrated the reliability of the techniques, accumulated a sizeable normal data bank, and developed a concise, effective data summary for communication with referring practitioners.

Amputees↗

PubMed1983

Changes in knee function associated with treadmill ambulation.

A comparison of level walking, on a walkway and on a treadmill, was performed using ten normal subjects. Motion about the knee was measured using a triaxial electrogoniometer, and foot-floor contact patterns were recorded by means of four foot switches attached to the sole of each shoe. On the walkway, the data were collected with the subject moving at a comfortable walking speed. The treadmill was then set at the average velocity obtained on the walkway. Knee joint rotation in the coronal and transverse planes did not change significantly between the walkway and the treadmill. In the sagittal plane, significant differences were found for total motion (p less than 0.01), swing phase motion (p less than 0.01), knee position at heel strike (p less than 0.05), and maximum swing phase extension (p less than 0.01). A comparison of the foot-floor contact patterns between walkway and treadmill ambulation revealed reduced heel contact time, with an increase in toe contact while on the treadmill. It was concluded that sagittal plane knee kinematics during level treadmill walking differ significantly from level overground walking.

Adult↗

PubMed1983

Normative data of knee joint motion and ground reaction forces in adult level walking.

A normative data base of temporal distance factors, knee joint motion and ground reaction force patterns for 148 adults during level walking is reported. The data were studied using parametric and non-parametric (Fourier series) representations to facilitate statistical analyses. Key parameters were divided according to age and sex. Individual force and motion curves of each normal subject were averaged to establish the 'typical' patterns. All typical patterns were combined to construct the 'general' patterns. The essential number and most significant Fourier coefficients were determined. It was found that the sex-related variation is more significant than the age-related variation in adult gait. This data base can serve as a common reference for comparison.

Adult↗

PubMed1983

Strength changes in the normal quadriceps femoris muscle as a result of electrical stimulation.

The purpose of this study was to examine the effectiveness of an electronic muscle stimulator in strengthening normal quadriceps femoris muscle without the assistance of simultaneous isometric muscle contraction. The sample consisted of 58 subjects who were randomly divided into three independent groups. One group (n = 19) served as controls; one group (n = 20) underwent daily stimulation of the right quadriceps femoris muscle using a specified protocol; and one group (n = 19) underwent isometric strengthening of the quadriceps femoris muscle using a specified protocol. The mechanical force of isometric quadriceps femoris muscle contraction was recorded weekly for the three groups, and the initial and final values were subjected to an analysis of covariance. The electrical-stimulation and isometric-exercise groups had statistically significant increases in quadriceps femoris muscle torque when compared with the nonexercised controls (p less than .001). The data supported the use of this electronic stimulator as an appropriate device for strengthening skeletal muscle without voluntary effort.

Adult↗

PubMed1980

Biomechanical gait evaluation of pre and postoperative total knee replacement patients.

Gait analysis based on the triaxial electrogoniometric method was carried out on a large group of normals and total knee replacement patients before and after surgery. Analysis of the objective gait variables was performed to compare the pre and postoperative results with that of the normals. Eight most significant gait variables were identified and from which two functional indices were calculated to provide an overall assessment of the reconstructive procedure based on disease type, side of involvement, and prosthetic design. It was found that total knee replacement provides significant functional improvement. Such improvement was more pronounced in certain patients, but its dependence on prosthetic type remained less conclusive. The results also suggested that there is a critical timing for surgery to obtain its maximum benefit. Knee function after joint replacement is a time-related phenomenon and, therefore, the patients must be followed beyond one-year postoperatively to provide more accurate assessment.

Biomechanical Phenomena↗

PubMedDate not supplied

Three-dimensional kinematics of the taped ankle before and after exercise.

The practice of prophylactic ankle taping or wrapping to reduce the incidence of inversion ankle sprains in athletes has come under attack. The purpose of this study was to measure objectively one ankle taping technique's ability to withstand the stresses placed upon it by a standardized exercise routine. Electrogoniometers were used to measure the three-dimensional ankle motion of 20 subjects walking on a level surface and a 10 degrees sideslope. The evaluations were carried out under these three conditions: (1) both ankles untaped, (2) both ankles taped before exercises, and (3) both ankles taped after exercise. The results from this study indicate that the tape does indeed restrict those motions associated with inversion ankle sprain. Methods similar to those described in this study could be used in the evaluation of many current training room practices and thereby provide an objective rationale for their application.

Adult↗

PubMedDate not supplied

Objective technique for evaluating painful heel syndrome and its treatment.

The biomechanical evaluation of patients with painful heels has received only limited attention although the potential morbidity and disability associated with such an ailment can be severe. An objective analysis of the patient's foot function during gait can produce useful information to assess the underlying pathology. This method can also help to evaluate the efficacy of various existing treatment protocols. The impulse distribution based on foot-floor vertical reaction force and time under the hind-, mid-, and forefoot was determined in 32 normal subjects while walking in their usual street shoes. Variations related to shoe types were noted, with high heeled shoes causing the most significant deviations from normal. The same technique was applied to 13 painful heel syndrome patients. Characteristic deviations from the normal impulse distribution were noted in these patients which provided the basis for differentiating the pathological condition between the patients with painful heel pads and those with plantar fasciitis. The effectiveness of using heel cups as a therapeutic device was also assessed. Although significant gait changes were not associated with the insertion of heel cups, they did seem to shift the foot-floor impulse forward from the heel region, which made them effective in patients afflicted with localized heel pain, but not in those with plantar fasciitis.

Adult↗

PubMedDate not supplied

Biomechanical analysis of foot function during gait and clinical applications.

Temporal and distance gait factors, foot-switch contact patterns, ankle/subtalar joint motion, and center of foot pressure distribution have been used to evaluate normal and abnormal foot mechanics. A normal control group and selected patients with well defined pathologic conditions were studied to examine the effectiveness of this method. Biomechanical observations reflect the clinical pathologic condition. Abnormalities involving the forefoot, midfoot, and hindfoot are most suitable for analyzing center of foot pressure. Ankle and subtalar problems are studied by motion analysis, with the subject walking on different ground conditions.

Adult↗