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1173 
DEVICES 
Methods for Estimating the Proper Length of a Cane 
Rajeswari Kumar, MD, Meng Cheng Roe, AID, Oscar U. Scremin, MD, PhD 
ABSTRACT. Kumar R, Roe MC, Scremin OU. Methods for 
estimating the proper length of a cane. Arch Phys Med Rehabil 
1995;76:1173-5. 
Objective: To find a practical method of cane length mea- 
surement that achieves the elbow flexion of 20 ° to 30 ° . 
Design: Two standard methods of cane length measurements 
were compared. Method I: Length of the cane measured from 
the floor to the top of the greater trochanter. Method II: Length 
of the cane measured from the floor to the distal wrist crease. 
Using an adjustable cane, each individual was fitted according 
to the two methods, and elbow angle was measured after each 
adjustment. Cane length was also correlated with arm length 
and height. 
Participants: Fifty-two normal volunteers who were ambula- 
tory without assistive devices. 
Results: Mean _+ SD of the elbow angle according to Method 
I and Method II was 44.8 _+ 11.8 and 25.4 + 6.1, respectively. 
A significant difference was found in the elbow angle between 
the two methods (unpaired two-tailed student t test, p = 
5.910-18). Of the 52 volunteers, 4 (7.7%) measured according 
to method I and 49 (94.3%) measured according to method II 
showed the elbow angle between 20 ° and 30 ° . The ideal length 
of the cane (L) also can be determined by the formula L = H 
× .45 + .87 meters or A × .76 + .19 meters, where H is the 
height of the individual in meters and A is the arm length 
measured in meters. 
Conclusion: Ideally, cane length should be measured from 
the floor to the distal wrist crease. The length can also be deter- 
mined using the above formulae. 
This is a US government work. There are no restrictions on 
its use. 
C ANES are among the most commonly prescribed ambula- tory devices. They are helpful in unloading painful joints 
and in stabilizing the ambulation in patients with impaired bal- 
ance.~'2 The degree of assistance they provide varies consider- 
ably from one patient to another. 
In 1967, Jebson 3 reported that a cane of ideal length should 
produce up to 30 ° of elbow flexion, "which allows the arm to 
lengthen and shorten at different phases of gait cycle." The 
current standard recommendation for prescription of a cane is 
that its ideal length should produce 20 ° to 30 ° of elbow flexion. 3'4 
Although there are several guidelines for measuring the 
From the Department of Physical Medicine and Rehabilitation, Veterans Affairs 
Medical Center, and Department of Medicine, University of California at Los 
AngeLes School of Medicine (Dr. Kumar); University of California at Los Angeles 
Multicampus Residency Program in Physical Medicine and Rehabilitation, Veter- 
ans Affairs Medical Center (Dr. Roe); and Geriatric Research, Education, and 
Clinical Center, Veterans Affairs Medical Center, and Department of Physiology, 
University of California at Los Angeles School of Medicine (Dr. Scremin). 
Submitted for publication January 17, 1995. Accepted in revised form May 23, 
1995. 
No commercial party having a direct financial interest in the results of the 
research supporting this article has or will confer a benefit upon the authors or 
upon any organization with which the authors are associated. 
Reprint requests to Rajeswari Kumar, MD, PM&R Service, W 117, West Los 
Angeles Veterans Affairs Medical Center, Wilshire and Sawtelle Boulevards, Los 
Angeles, CA 90073. 
This is a US government work. There are no restrictions on its use. 
0003-9993/95/7612-338050.00/0 
length of crutches in a clinical setting, the guideline for mea- 
surement of canes has been poorly defined. The elbow angle 
can be measured with a goniometer while the patient is being 
fitted with a cane; however, this is not a practical method in a 
clinical setting. One commonly used method for determining 
proper cane length is to measure the distance from the floor to 
the greater trochanter. 3'4 However, there is no documentation 
that this method provides the desired elbow flexion. The present 
study compared two methods of measuring cane length to deter- 
mine which one produced elbow flexion of 20 ° to 30 ° and to 
develop guidelines for cane length measurement in a clinical 
setting. 
METHODS 
Fifty-two normal volunteers who were ambulatory without 
assistive devices participated in this study. An adjustable cane 
was used for measurements. Two methods were used to deter- 
mine cane length. 
Method 1. The person stood erect wearing comfortable, flat 
shoes. The length of the cane was adjusted so that the top of 
the cane corresponded to the top of the greater trochanter. The 
lower tip of the cane was placed at a point 6 inches lateral to 
the little toe. 
Method 2. The person stood with the arm hanging loosely 
close to the body. The cane length was adjusted so that the top 
of the cane was at the distal wrist crease. The lower tip of the 
cane was again placed at a point 6 inches lateral to the little 
toe. 
After adjustment of the cane, the person held the cane as if 
using it to walk, and the elbow angle was measured. To measure 
the angle, the center of the goniometer was placed in the lateral 
epicondyle. By palpating along the spine of the scapula, the 
acromion was localized. By palpating further laterally, the mid- 
point on the lateral end of the acromion was located. One arm 
of the goniometer was placed on the lateral aspect of the arm 
along the long axis of the humerus connecting this point on 
the acromion to the lateral epicondyle. The other arm of the 
goniometer was placed in the middle of the forearm. 
The actual length of the cane was measured after each adjust- 
ment using a tape measure. 
To find the relationship between arm length (A) and length 
of the cane (L), arm length was measured in 41 volunteers. To 
measure arm length, the individual stood erect with the arm in 
90 ° of abduction and the elbow, wrist, and fingers in extension. 
The arm length was measured from the sternal notch to the tip 
of the middle finger. 
The height was measured in meters in 15 individuals. To 
measure the height, the person stood with comfortable, flat 
shoes in front of the scale. Because statistical analysis in 15 
people showed no significant difference between the reported 
and measured height (Pearson correlation, r = .8011, p < 
.0001), only the reported height was recorded for the rest of the 
37 individuals. 
Statistical analysis. An unpaired two-tailed student t test 
was used to compare the elbow angle between the two methods. 
Regression analysis was used to compare height and arm length 
with the cane length measured according to Method 2. 
Arch Phys Med Rehabil Vol 76, December 1995 
1174 ESTIMATING PROPER CANE LENGTH, Kumar 
Occurrenl 
20 
16 
12 
E lbow A 
[u 
; cur rences 
20 
16 
12 
} 
Fig 1. The elbow angle obtained 
when cane length was measured 
according to method 1 (trochan- 
ter) and method 2 (wrist) (n = 
52). Pooled value (men and 
women) of elbow angle with 
method 1 was significantly dif- 
ferent from method 2 (unpaired 
two-tailed student ttest; p = 1.2 
× 10 le). 
RESULTS 
Fifty-two volunteers with ages ranging from 22 to 78 years 
participated in the study. Mean age (mean ± SD) was 35.7 ± 
11.12 for women and 45.04 ± 19.2 for men. There were 21 
men and 31 women. Measurement of the elbow angle that re- 
sulted when cane length was determined according to method 
1, ie, floor to the greater trochanter, showed that only 4 of 52 
(7.7%) subjects had the elbow angle between 20 ° and 30 ° and 
the rest of the subjects had an elbow angle greater than 31 ° (fig 
1). However, when cane length was determined according to 
method 2, ie, from the floor to the distal wrist crease, the re- 
sulting elbow angle was between20 ° and 30 ° in 49 of 52 
(94.3%) subjects, and only 3 of 52 (5.7%) had an elbow angle 
greater than 31 ° (fig 1). Regression analysis showed that age 
did not correlate with the resulting elbow angle (fig 2). Since 
there was no correlation between gender and the elbow angle 
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40 
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Age (years ) 
Fig 2. The relationship between age and elbow angle In = 52). The coeffi- 
cient of the regression of the elbow angle on age, on age obtained by 
least squares method, was not statistically significantly different from 
zero. 
(table 1), the data from both genders were pooled. Mean _ SD 
of the elbow angle according to method 1 was 44.8 + 11.8 (n 
= 52) and according to method 2 was 25.4 ± 6.1 (n = 52). 
There was a significant difference between the mean of the elbow 
angle between the two methods (unpaired two-tailed t test; p = 
5.9 x 10 ,8) (fig 1). A significantly greater number of people 
achieved an appropriate elbow angle using method 2. 
Regression analysis showed that the length of the cane (L) 
can be determined from the formula L = A x .76 + .19m, 
where A is the ann length measured from the sternal notch to 
the tip of the middle finger with the arm abducted at 90 ° and 
elbow, wrist, and fingers in extension (fig 3). Regression analy- 
sis also showed that the height of the individual is twice the 
length of the arm (Arm length [A] = .50 x H + .01m, where 
H is the height of the individual). Thus, a significant correlation 
was also found between the length of the cane and the height 
of the subjects. The length of the cane (L), therefore, can also 
be determined by the formula L = H x .45 + .087m (fig 4). 
DISCUSSION 
Canes are the most commonly prescribed walking aids. 2 They 
increase the base of support and reduce the fear of instability 
Table 1: Elbow Angle, Cane Length, Height, and Arm Length 
Measurements (n = 52) 
Mean SD Cl(U) CI(L) 
Elbow angle (°) M1 (M) 43,86 10.10 48.45 39.26 
Elbow angle (°) M1 (F) 45.70 12.51 50.33 41.15 
Elbow angle (°) M2 (M) 25.10 4.71 28.10 23,80 
Elbow angle (°) M2 (F) 25.13 6.39 27.47 22.78 
Cane length (m) M1 (M) .94 .04 .96 .92 
Cane length (m) M1 (F) .78 .05 .90 .87 
Cane length (m) M2 (M) .87 .05 .89 .85 
Cane length (m) M2 (F) .81 .05 .83 .79 
Height (m) (M) 1.7 .08 1.78 1.70 
Height (m) (F) 1.63 .08 1.66 1.60 
Arm length (m) (M) 39 .05 .92 .86 
Arm length (m) (F) .83 .04 .81 .81 
Age (yr) (M) 35.71 11.12 40.03 31.40 
Age (yr) (F) 45.05 19.26 53.82 36.28 
There was no significant difference in any of the variables measured 
between genders. 
Abbreviations: CI(U), upper 95% confidence interval; CI(L), lower 95% 
confidence interval; M, men; F, women; M1, method 1; M2, method 2. 
Arch Phys Med Rehabil Vol 76, December 1996 
ESTIMATING PROPER CANE LENGTH, Kumar 1175 
in elderly people. 2 By using canes properly during ambulation, 
the weight-bearing forces in the lower extremity can be re- 
duced. 1'2 Some patients, however, receive canes from friends or 
relatives, or choose them on their own. These canes may not 
provide proper support or unload a painful joint in the lower 
extremity. Many studies have determined force transmission 
through canes. 5-7 However, methods for proper determination 
of a cane's length have not been reported. One previous study 
showed that two thirds of elderly people used a cane that was 
too long. 8 Canes that are too long raise the shoulder and cause 
an increase in flexion of the elbow. Canes that are too short 
cause the user to lean toward the cane while standing, and lean 
forward while placing the cane forward when walking. 8 It is 
controversial whether walking devices that are not properly 
measured might contribute to falls in the elderly, s'9 
With the application of instrumented crutches, canes, force 
platform, and special camera system, Opila and colleagues j° 
recorded the axial and shear forces on walking aids and limbs. 
The values were plotted as histograms. Recording of such forces 
with different walking aids in patients with different disabilities 
was reported to be beneficial in gait training and proper prescrip- 
tion of walking aidsJ ° However, expensive equipment, such as 
a force platform and a special camera system, was required. 
Jebsen 3 initially made the assumption that canes may be used 
to support 20% to 25% of body weight and canes of ideal 
length produce 20 ° to 30 ° of elbow flexion, in which case elbow 
extensors act as shock absorbers. Later studies using an instru- 
mented cane proved that axial loading on the cane varies be- 
tween 15% to 40% of body weight. 7'~° 
Static analysis of upper limb loading while using a cane 
showed that elbow joint force and muscle moment force at the 
elbow depend on the amount of flexion at the elbow. Muscle 
moment force at the elbow is provided by elbow extensors, 
which help to counteract the tendency of cane forces to induce 
elbow flexion. 2 If the cane is fitted with the arm in full extension, 
the muscle moment force at the elbow is negligible. This ap- 
pears ideal for reducing the muscle moment force at the elbow. 
However, the patient who is fitted with the arm in full extension 
will lean forward to advance the cane while walking. Longer 
1.2 
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0.6 
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• • • 
I F I 
.7 0,8 0.9 1 
Arm Length (meters) 
Fig 3. The relationship between arm length and cane length (n = 41). 
The parameters of regression equation of wrist to floor distance on arm 
length estimated by the least squares method were coefficient .76X + 
.17 (intercept = .19, • = .85). 
1.2 
¢/b 
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o 
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0.7 
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1.5 1.6 1.7 1.8 1.9 
HEIGHT (meters} 
Fig 4, The relationship between height and cane length (n - 52) as mea- 
sured by wrist to floor (method 2). Parameters of regression equation 
of cane length by method 2 on height estimated by the least squares 
method were coefficient .45X + .087 (intercept = .087, • = .086). 
canes cause an increase in elbow flexion, an increased demand 
on triceps, and an increase in muscle moment force at the elbow. 
The current recommendation agrees with the previous sugges- 
tion that the cane should provide 20 ° to 30 ° of elbow flexion. ~'2'4 
The commonly used method for cane length measurement, how- 
ever, has not been documented to provide 20 ° to 30 ° of elbow 
flexion. 
One previous study showed that there are discrepancies in 
the length of the cane measured when the cane is measured 
from the floor to the greater trochanter and when the cane is 
measured from the floor to the ulnar styloid process) Our study 
clearly shows that the conventional method of measuring the 
cane from the floor to the greater trochanter is not an effective 
method. The cane should be measured from the floor to the 
distal wrist crease to provide the expected elbow angle. 
We have also developed other formulae for measurement of 
a cane in a clinical setting. The length of the cane can be 
calculated if a person's height or arm length is known, using 
the formula given above. 
References 
1. Blount WP. Don't throw away the cane. J Bone Joint Surg Am 
1956; 38A:695-708. 
2. Deathe AB, Hayes KC, Winter DA. The biomechanics of canes, 
crutches, and walkers. Crit Rev Phys Rehabil Med 1993;5:15-29. 
3. Jebsen RH. Use and abuse of ambulation aids. JAMA 1967; 199:63. 
4. Ragnarson K. Orthotics and shoes. In: DeLisa JA, editor. Rehabilita- 
tion medicine: principles and practice.Philadelphia: Lippincott, 
1988:310. 
5. Murray MP, Seireg AH, Scholz RC. A survey of the time, magni- 
tude and orientation of forces applied to walking sticks by disabled 
men. Am J Phys Med Rehabil 1969;48:1-13. 
6. Edwards BG. Contralateral and ipsilateral cane usage by patients 
with total knee or hip replacements. Arch Phys Med Rehabil 
1986;67:734-40. 
7. Ely DD, Smidt GL. Effect of cane on variables of gait for patients 
with hip disorders. Phys Ther 1977;57:507-12. 
8. Mully GP. Walking sticks. BMJ 1988;296:475-6. 
9. Sainsbury R, Mulley GP. Walking sticks used by the elderly. BMJ 
1982; 284:1751. 
10. Opila KA, Nicol AC, Paul P. Forces and impulses during aided 
gait. Arch Phys Med Rehabil 1986;68:715-22. 
Arch Phys Med Rehabil Vol 76, December 1995