Journal of Orthopaedic & Sports Physical Therapy - David Tiberio, PT, PhD, OCS

The Effect of Excessive Subtalar Joint Pronation on Patellofemoral Mechanics: A Theoretical Model

Mon, 15 Sep 2008 00:00:00 EST

David Tiberio
Excessive compression of the lateral articular surfaces is frequently a major component of patellofemoral dysfunction. Many subjects exhibiting symptoms of this disorder have structural deviations throughout the lower extremity which combine to produce malalignment of the patellofemoral joint. Included in these malalignment factors is excessive pronation of the subtalar joint. Excessive rotation of the lower leg which accompanies subtalar joint pronation has been cited as a major contributor to patellofemoral dysfunction. Although the excessive rotation of the lower leg will disrupt the normal mechanics of the tibiofemoral joint, the specific link between tibial rotation and patellofemoral symptoms has not been established. This paper presents a theoretical model which describes the compensation that can occur at the tibiofemoral joint to deal with the excessive tibial rotation. The link between the tibiofemoral compensation and increased patellofemoral compression is delineated. Factors which determine whether this increased compression becomes symptomatic are discussed.

J Orthop Sports Phys Ther 1987;9(4):160-165.

Motion Measured from Forefoot and Hindfoot Landmarks During Passive Ankle Dorsiflexion Range of Motion

Wed, 10 Sep 2008 00:00:00 EST

Richard W. Bohannon, David Tiberio, Gregory Waters
This project was funded, in part, by the Research Foundation, University of Connecticut, Storrs, CT 06269-2101.

The purpose of this study was to document and compare, using surface landmarks, the magnitude of forefoot and hindfoot motion accompanying passive ankle dorsiflexion range of motion (ADROM). Twenty-two healthy subjects had their right ankle passively dorsiflexed two times from a resting position to a maximum dorsiflexion while they were supine and their subtalar joints were positioned in neutral. Initial resting position and maximum ADROM were measured from surface markings over the fibula, fifth metatarsal, and heel in pictures taken with a 35 mm camera. The difference between the maximum ADROM and the initial measurements obtained from the markings over the fifth metatarsal and heel were used to represent motion of the forefoot and hindfoot, respectively. The grand mean forefoot motion (39.8°) and hindfoot motion (37.1°) were significantly different (F = 13.62, p ≤ 0.001). The motions, however, were significantly correlated for the two trials (r = 0.905 and 0.704). The small magnitude of the difference (= 2.7°) in forefoot and hindfoot motion and significant correlations between the motions challenge the need for foot stabilization other than maintaining the subtalar joint in neutral.

J Orthop Sports Phys Ther 1991;13(1):20-22.

Kinematics of the Double-Leg-Lowering Test for Abdominal Muscle Strength

Mon, 11 Dec 2006 00:00:00 EST

Chad M. Zannotti, Richard W. Bohannon, David Tiberio, Michael J. Dewberry, Richard Murray
Study Design: Prospective descriptive study.

Objective:To investigate the kinematics of the double-leg-lowering (DLL) test of abdominal muscle strength.

Background: Adequate strength of the abdominal muscles is necessary for many household, occupational, and sports activities. Therapists, therefore, need valid measures of abdominal muscle strength.

Methods and Measures: A convenience sample of 17 subjects (7 women, 10 men) was tested. Using reflective spheres to identify specific body segments, subjects were videotaped while performing DLL under 2 conditions: attempting (controlled) prevention of anterior pelvic tilting versus not attempting (uncontrolled) prevention of anterior pelvic tilting. Videotape was analyzed using the PEAK 5 2-dimensional system.

Results: The pelvis tilted anteriorly by the time the extremities were lowered a mean 3.6°, regardless of condition. No significant difference in anterior pelvic tilting was associated with the 2 DLL conditions (F = 2.95, P = 0.105) but pelvic tilting did increase significantly as the lower extremities were lowered from vertical (F = 98.41, P < 0.001).

Conclusions: There appears to be a natural tendency for the pelvis to tilt anteriorly from very early in the DLL maneuver. As healthy young subjects do not appear able to prevent the tilting, the scoring system associated with the DLL test should be questioned.

J Orthop Sports Phys Ther. 2002; 32(9):432–436.

Keywords: examination, lower extremity, pelvis, physical therapy, trunk