Some biomechanical aspects of crutch and cane walking: the relationship between forward rate of progression, symmetry, and efficiency--a case report.

The purpose of this case report is to review the progression of crutch ambulation typically used in the management of lower extremity injuries, and to describe some biomechanical parameters of gait using assistive devices. A comparison is made between weight bearing status and the use of different devices (that is, axial crutches, cane). Unilateral versus bilateral and nonreciprocal versus reciprocal crutch gait patterns are evaluated. Review of the data showed bilateral use of crutches helped to maintain the symmetry of gait as was demonstrated when right and left cycle times and right and left stride lengths were compared. Symmetry was maintained for most bilateral crutch gaits with the exception of the NWB (three-point) pattern. This trial represents, by definition, an asymmetrical condition. The comparison of nonreciprocal versus reciprocal FWB crutch gaits revealed little objective difference in the parameters studied. However, it is the authors' view that a two-point reciprocal crutch gait more closely approximates normal gait, and therefore should be encouraged. It is possible that consideration of different parameters (for example, electrogoniometric analysis of joint angles) might demonstrate an objective difference between nonreciprocal and reciprocal gait patterns. When a single assistive device was used (crutch or cane) asymmetries were demonstrated. When single crutch and single cane trials were compared obvious asymmetries in cycle time and stride length were noted in the former. A single axial crutch splints the upper trunk, thereby decreasing pelvic/trunk rotation and reducing reciprocal arm swing. Using a cane substantially improves symmetry and forward rate of progression by increasing rotation and reciprocal arm swing. The authors believe this finding is significant and should be considered when selecting a unilateral device. Indeed, these findings suggest it may, under certain circumstances, be more appropriate to forego the use of a unilateral crutch. Perhaps the most obvious effect assistive devices have on gait is to decrease the rate of forward progression. When (unassisted) PRA was compared with trials in which assistive devices were used, velocity and cadence decreased. Asymmetries of gait lead to distortions in the path of the center of gravity, which manifest as increased energy expenditure. Energy expenditure is similarly affected when the rate of forward progression varies from an optimal rate. Using an inappropriate assistive device decreases forward rate of progression and therefore may lead to inefficient ambulation under certain circumstances.(ABSTRACT TRUNCATED AT 400 WORDS)