Effect of simulating leg length inequality on pelvic torsion and trunk mobility.

Although techniques such as roentgenograms and magnetic resonance imaging can provide definitive information about leg length inequality, they are not easily implemented for screening purposes. Using relative heights of palpated iliac crests as criteria for determining degree of lateral pelvic tilt, we examined the immediate effect of simulating leg length inequality on pelvic torsion and trunk flexion. In seven healthy men and 22 healthy women, 18-28 years of age, a lift of at least 15 mm was placed under either foot to laterally tilt the pelvis 1.2 degrees or more. In eight subjects with pre-existing lateral pelvic tilts of 1.8 degrees or more, a lift was also used to eliminate the tilt. We examined how this tilting affected torsion between the innominates and mobility of the trunk. The innominate contralateral to the lift became more anteriorly rotated than the ipsilateral innominate and lateral flexion of the trunk increased toward the side of the lift. Both of these effects can be associated with clinical leg length inequality, so a lateral pelvic tilt on the order of 1.2 degrees, if encountered in the clinic, should signal the suitability of more extensive examination for possible lower limb asymmetry.

Effect of head position on vertical mandibular opening.

STUDY DESIGN: A within-subjects repeated measures design. OBJECTIVES: To determine differences in the amount of vertical opening of the mandible among 3 different head positions. BACKGROUND: Results from several studies have suggested that the position of the head and neck may affect temporomandibular joint function. Presently no standardized position of the head and neck has been recommended for measuring vertical opening of the mandible. METHODS AND MEASURES: Twenty males and 20 females (32.9 +/- 8.3 years) participated in the study. We obtained 3 measurements of vertical mandibular opening using a millimeter ruler on each subject in the forward, neutral, and retracted head positions. RESULTS: A 1-way repeated measures analysis of variance followed by pairwise comparisons indicated that the vertical mandibular opening was significantly greater in the forward head position (44 +/- 5.3 mm) than in the neutral head position (41.5 +/- 4.8 mm) and in the retracted head position (36.2 +/- 4.5 mm). In addition, vertical mandibular opening was significantly greater in the neutral head position than in the retracted head position. Interclass correlation coefficients for the 3 head positions ranged from 0.90 to 0.97 for intrarater, interrater, and day-to-day reliability. CONCLUSIONS: Head position is an important factor in determining the amount of vertical mandibular opening in healthy adults.

Assessment of anteroposterior instability of the knee during gait.

A noninvasive kinematic recording technique involving geometric modeling of the knee joint was employed to determine anteroposterior displacements of the knee during walking. The model estimated how much the femoral condyles slid and rolled on the tibial plateau. Movement not due to sliding or rolling was attributed to horizontal translation of the tibia with respect to the femur. Thirty normal adults participated in this study. A three-dimensional analysis system with noninvasive skin markers was employed to collect kinematic data of the femur and tibia during walking. Within-session and between-session reliabilities were high in the tested subjects. Normal subjects had an average of 5.5 mm of maximum anterior displacement of the tibia during stance phase of walking. These results differed neither between left and right knees, nor between men and women. Dynamic instability of the knee during walking can be reasonably measured by the proposed method in normal subjects.

Short-term effect of correcting leg length discrepancy on performance of a forceful body extension task in young adults.

In this study we assessed the short-term effect of correcting leg length discrepancy on a vigorously performed task of resisted full body extension in 10 men, 18 to 35 years old, who had estimated leg length discrepancies of 10-15 mm. Using a cable ergometer we examined work performed, initial peak tension exerted on the ergometer, second peak tension, time to first peak tension, and mean velocity of the whole task. Each subject performed the task both with and without a heel lift, introduced to equalize leg length. The interval between testing under these two conditions was 48 hr. In the task of pulling the cable upward, each subject began from floor level with knees and trunk flexed, progressing to full body extension with the arms pulling the cable overhead with maximal effort. For each trial the task was repeated 15 times, with intervals of 90 seconds between the repetitions. Use of the lift failed to have a statistically significant effect on any of the variables, although it clearly enabled three of the subjects to exert greater strength with the arms and trunk during the second peak tension. This suggests that 1) overall body extension is influenced by too many factors to be affected in a consistently predictable way by a heel lift to correct leg length discrepancy, and 2) the heel lift may aid certain subjects with leg length discrepancy specifically during extension of the trunk in this task.

A weight bearing method for determining forefoot posting for orthotic fabrication.

Orthotic prescription for forefoot posting is commonly based upon measures of the forefoot performed on a non-weightbearing foot. However, the relationship of measures of the unloaded foot to determine orthotic prescription for compensatory forefoot function during gait is still in question. Another approach to determine orthotic prescription is to measure the height of forefoot posting necessary to prevent excessive pronation of the subtalar joint during weightbearing. Therefore, the purpose of this study was to determine the intrarater, interrater and day-to-day reliability of forefoot measures during an active, weightbearing movement. Thirty-two volunteers, 18 females (mean age 38.9 +/- 15.3 yr) and 18 males (mean age 44.8 +/- 20.6 yr) participated in the study. Four examiners performed repeated forefoot measures on both feet using the weightbearing technique during two test sessions separated by a week. Intrarater and interrater reliability (ICC (3,1)) ranged from 0.90 to 0.95 and 0.87 to 0.94, respectively. Day-to-day reliability (ICC (1,1)) ranged from 0.84 to 0.88 for all measures. We conclude that the weightbearing method used in this study to determine forefoot posting is reliable. The acceptable reliability of this method justifies the need for future investigations of the validity and the clinical efficacy of this technique for orthotic prescription.

The effect of nontraumatic immobilization on ankle dorsiflexion stiffness in rats.

Experimental evidence supports the general conclusion that 6 or more weeks of immobilization will cause joint contractures due to changes in the capsules of animals whose limbs have been traumatized. There is controversy whether contractures will form in 6 weeks in limbs which are free of trauma. The purpose of this study was to determine if range of motion would be lost in ankle joints of rats following nontraumatic immobilization of the hindlimb for 2 or 6 weeks. The right hindlimb of each animal was immobilized in a plaster cast for 2 or 6 weeks with the left hindlimb serving as a matched control (N = 8). Nonimmobilized rats served as additional controls (N = 4). Following 2 or 6 weeks of immobilization, each rat was sacrificed and the lower leg removed at the knee. An electrogoniometer measured the change in dorsiflexion as torque was applied in increasing increments to the ankle. Load-deformation tests were performed to determine: 1) torque to end range of dorsiflexion, 2) joint excursion with application of 3.57 mNm torque for 2.5 seconds, and 3) joint excursion with prolonged application of 3.57 mNm torque. Only the group casted for 6 weeks demonstrated a significant (p < 0.05) decrease in both degrees of dorsiflexion and joint compliance. The group casted for 6 weeks required five times more torque to achieve end range than the other groups and had a 70% decrease in ankle dorsiflexion when a fixed torque of 3.57 mNm was applied. No significant differences were noted among the remaining groups. These findings suggest that in nontraumatically immobilized joints of rats, dense connective tissue remodels in such a way that mobility is unaffected after 2 weeks, but becomes quite limited by 6 weeks.

Intratester and intertester reliability and validity of measures of innominate bone inclination.

Determination of innominate bone inclination in standing is frequently assessed in postural analysis of subjects. Currently, no goniometer for objective assessment of innominate bone inclination in standing is commercially available. The purpose of this study was to determine the intratester and intertester reliability and validity of measures taken with a pelvic inclinometer. The intraclass correlation coefficient (ICC) for repeated measures of the pelvic inclinometer fixed to a mechanical model was 0.99. The intertester reliability of using the hand-held pelvic inclinometer to determine inclination on a mechanical model was ICC = 0.99. In measures of 20 male subjects by three testers, the ICC for intertester reliability was 0.95 and the range of ICCs for intratester measures was 0.92-0.96. Measures by the inclinometer had a high degree of reliability compared with the criterion roentgenographic measure, ICC = 0.93. Measurement of the inclination of both left and right innominate bones of a subject required only 2 minutes, indicating clinical applicability.

Effects of three different posting methods on controlling abnormal subtalar pronation.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the effects of different orthotic posting methods on controlling abnormal foot pronation during ambulation. SUBJECTS: Twenty-two individuals with forefoot varus deformities of at least 8 degrees (13 women, aged 21-40 years, and 9 men, aged 20-50 years) participated in the study. The female subjects had an average height and weight of 162.6 cm (64 in) and 55.3 kg (122 lb), and the male subjects had an average height and weight of 175.3 cm (69 in) and 80.7 kg (178 lb). METHODS: The subjects were examined with a computerized video motion analysis system. A control trial consisted of walking at 4.0 km/h in running shoes. Experimental trials included walking at 4.0 km/h in running shoes with unposted orthotic shells and with orthotic shells posted in the forefoot, the rear foot, and both forefoot and rear foot. RESULTS: Maximal calf-to-calcaneus and calcaneus-to-vertical angles were decreased more by orthoses posted in both the forefoot and the rear foot than by orthoses posted only in the forefoot. No difference in maximal calf-to-calcaneus and calcaneus-to-vertical angles were found with combined forefoot and rear-foot posting compared with posting in the rear foot alone. The maximal calf-to-calcaneus angle was decreased by orthoses posted in any of the three methods and by the orthotic shell alone when compared with shoes alone. The maximal calcaneus-to-vertical angle was decreased by orthoses posted in any of the three methods, but not by the orthotic shell alone when compared with shoes alone. CONCLUSION AND DISCUSSION: Clinicians should consider combined posting or rear-foot posting alone when maximal control of rear-foot frontal-plane pronation is desired, though forefoot posting alone and the orthotic shell also provide control of rear-foot frontal-plane pronation.

Isokinetic measurement of foot invertor and evertor force in three positions of plantarflexion and dorsiflexion.

The purpose of this study was to determine the ankle position at which the greatest peak torque occurs during isokinetic testing of inversion and eversion force. Testing of right foot invertors and evertors was performed at 10 degrees dorsiflexion, neutral dorsiflexion and plantarflexion, and 10 degrees plantarflexion on 25 untrained subjects with the MERAC isokinetic dynamometer. Subjects were retested to determine reliability. Results indicate that 10 degrees plantarflexion appears better than the other positions tested because reliability was highest and torque output was greatest at this position. Reliability was assessed with a Pearson product moment test and a paired comparisons test (p

Source of error in clinical assessment of innominate rotation. A special communication.

The sacroiliac joint (SIJ) is a possible source of low back pain or dysfunction. Various methods of visually assessing the relative position of the innominate to the sacrum have been used to evaluate SIJ dysfunction. The purpose of this special communication is to describe how a false-positive interpretation of innominate rotation may occur when a leg-length difference exists and visual assessment is used.

Accuracy of the unassisted pain drawings by patients with chronic pain.

This investigation was conducted to test the accuracy of unassisted pain maps drawn by patients with chronic pain. Three aspects of accuracy were investigated, the accuracy of the area of pain reported, whether all existing pains were reported, and whether related symptoms were reported. Thirty-six successive new admissions to a chronic pain rehabilitation center were used as subjects. Each patient filled out the pain map prior to meeting any professional staff. During their examination the investigators completed a new pain map without seeing the patient's map. Thirty-one pairs of pain maps were compared and scored, with most maps showing several pain areas. Area of pain was accurately represented 43% of the time. Of 139 distinct pains found during examination, only 58% were reported in the pain maps. Thirtyfour percent of related symptoms were reported. It appears that unassisted pain maps are sufficiently flawed to discourage their use as an indicator of the patients symptom location J Orthop Sports Phys Ther 1987;8(8):391-396.

Comparison of muscle to other soft tissue in limiting elbow extension.

Nine middle-aged women were examined to determine whether extension of the elbow in normal adults is limited primarily by muscle, or by ligaments and capsule. Terminal range of elbow extension was measured when the subject was normally relaxed and in the same subjects under conditions of paralysis induced by a myoneuro blocking agent. Relaxation of the unparalyzed subject was confirmed with a biofeedback machine. Paralysis resulted in increased elbow extension in all subjects. Since the myoneuro blocking agent affects only muscle and not the connective tissue, it is concluded that elbow extension in the normal adult woman is limited primarily by muscle.J Orthop Sports Phys Ther 1984;5(4):170-174.