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Shoulder pain in wheelchair users with tetraplegia and paraplegia
453
Shoulder Pain in Wheelchair Users With Tetraplegia and Paraplegia Kathleen A. Curtis. PhD. PT. George A. Drvsdale. BS. R. David Lunza, MSPT, Morey Kolber, MSPT, Richard S. Vitolo, kSP$ Rdnald 6’est, M,$PT ’ ’ ABSTRACT. Curtis KA, Drysdale GA, Lanza RD, Kolber M, Vitolo RS, West R. Shoulder pain in wheelchair users with tetraplegia and paraplegia. Arch Phys Med Rehabil 1999;80: 453-7. Objective: To compare the prevalence and intensity of shoulder pain experienced during daily functional activities in individuals with tetraplegia and individuals with paraplegia who use manual wheelchairs. Design: Self-report survey. Setting: General community. Participants: Fifty-five women and 140 men, 92 subjects with tetraplegia and 103 subjects with paraplegia who met inclusion criteria of 3 hours per week of manual wheelchair use and at least 1 year since onset of spinal cord injury. Main Outcome Measures: Respondents completed a demographic and medical history questionnaire and the Wheelchair User’s Shoulder Pain Index (WUSPI), a measure of pain during typical daily activities. Results: More than two thirds of the sample reported shoulder pain since beginning wheelchair use, with 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reporting current pain. Performance-corrected WUSPI scoreswere significantly higher in subjects with tetraplegia than in subjects with paraplegia. Conclusions: Both the prevalence and intensity of shoulder pain was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Efforts to monitor and prevent shoulder pain should continue after rehabilitation. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation N THE UNITED STATES there are an estimated 235,000 to Iestimated 265,000 individuals with spinal cord injury (SCI) and an additional 9,000 new injuries each year1 ApproxiFrom the Division of Physical Therapy, Department of Orthopaedics and Rehabilitation, University of Miami School of Medicine, Miami, FL (Dr. Curtis, Mr. Lanza, Mr. Kolber, Mr. kolo, Mr. West): and the Department of Physical Therapy, School of Health and Human Services. California State Universitv. Fresno. CA (Mr. Drvsdalej. Dr. Curtis is currently affiliated with the Department o?‘Physical Theiapy, Slhool if Health and Human Services. California State University, Fresno, CA. Mr. Kolber is currently affiliated with Lighthouse Orthopedics, Boca Raton, FL. Mr. Lana is currently affiliated with Egan Health Care, Metairie, LA. Mr. West is currently afkiliated with the Public Health Service-Phoenix Indian Medical Center, Phoenix, AZ. Mr. Vitolo is currently affiliated with the Veterans Administration Medical Center, West Palm Beach, FL. Submitted for publication August 4, 1998. Accepted in revised form October 22, 1998. Presented at Physical Therapy 98, Scientific Meeting and Exposition, American Physical Therapy Association, June 7, 1998, Orlando. FL. 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 Kathleen A. Curtis, PhD, PT, Physical Therapy Department, California State University, Fresno, 2345 East San Ramon Avenue/MS 29, Fresno, CA 93740-8031. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation 0003-9993/99/X004-5152$3.00/0
mately 53% of these individuals have cervical lesions (tetraplegia); the remaining 47% have lesions below the first thoracic level (paraplegia). Although advances in technology and health care have increased the life expectancy of individuals with SCI, many quality-of-life issues have surfaced related to secondary disabilities associated with aging.2-5 Most individuals with paraplegia and tetraplegia use wheelchairs for mobility at home, school, work, and play. Many wheelchair users experience upper extremity pain that interferes with essential activities of daily living such as wheelchair propulsion, driving, dressing, and transfers6z7Upper extremity weight-bearing activities and chronic overuse have both been implicated in the development of soft tissue disorders and degenerative changes in the shoulder jointslo Although several studies have documented the prevalence of upper extremity pain in manual wheelchair users, few authors have addressed related functional difficulties. Pentland and Twomeyl’ documented the functional implications of shoulder pain in 11 women with paraplegia, and reported that work and school activities, outdoor wheeling, household work/child care, and loading a wheelchair into a car were most commonly associated with shoulder pain. Curtis and colleaguesI2 also studied 64 long-term wheelchair users with SC1 and reported the highest intensity of shoulder pain during functional activities requiring extremes of shoulder range of motion, overhead positioning, or a high level of upper extremity strength. The most painful activities for these subjects included wheeling up inclines, reaching to an overhead shelf, sleeping, transfers to nonlevel surfaces, and washing their backs. Since individuals with tetraplegia are generally more limited in upper extremity strength and function than are persons with paraplegia, we might expect that wheelchair users with tetraplegia would experience a higher prevalence and intensity of shoulder pain during functional activities than would wheelchair users with paraplegia. This was supported by Sie and associates2 who observed that significantly more individuals with tetraplegia than individuals with paraplegia reported that they had experienced shoulder pain since their SC1 (46% and 36%, respectively). Neither the intensity of shoulder pain nor the difficulty it imposes during functional activities has been compared in wheelchair users with respect to level of SCI. Identification of these problems in the SC1 population has implications for detection, prevention, and treatment of musculoskeletal complications and resulting secondary disability. Therefore, the purpose of the current study was to compare the prevalence and intensity of shoulder pain during specific functional activities in individuals with tetraplegia and individuals with paraplegia. METHODS Subjects Subjects included 195 individuals with SCI, 55 women and 140 men, who used manual wheelchairs for at least 3 hours a Arch
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SHOULDER
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IN WHEELCHAIR
week. There were 92 subjects with tetraplegia; their average age was 32.9 (i 10.1) years, they had used their wheelchairs an average of 6.9 (k5.0) years, and 55% were employed or students. In comparison, there were 103 subjects with paraplegia; their average age was 34.4 (t 10.7) years, they had used their wheelchairs an average of 7.2 (26.5) years, and 65% of this group were employed or students. Instrumentation A self-administered questionnaire was used to collect demographic and medical history information and to assess the intensity of pain experienced during the performance of activities of daily living. Data collected included age, gender, marital status, duration of wheelchair use, level of SCI, frequency of wheelchair transfers per day, hours per week spent at work and/or school, in sporting/recreational activities, and driving, type of automobile driven, history of shoulder problems, presence and location of current shoulder pain, type of medical attention sought for shoulder pain, type of treatment received for shoulder pain, and presence of other upper extremity pain. We used the Wheelchair User’s Shoulder Pain Index (WUSPI), a 15-item valid and reliable questionnaire, to assess the intensity of pain during the performance of activities of daily living such as transfers, loading a wheelchair into a car, wheeling up inclines, dressing, bathing, overhead lifting, driving, performing household chores, and sleeping.13 Subjects rated their intensity of pain during these activities on a lo-cm visual analog scale (VAS) anchored at “no pain” and “worst pain ever experienced.” The total possible score on the scale ranged from 0 to 150. Procedures A packet, including a cover letter, consent form, questionnaire, and return mail envelope, was mailed to 700 individuals with SC1 who were registered with an SC1 research foundation. A follow-up postcard was mailed 3 weeks after the initial mailing to encourage a prompt response. Subjects returned a signed consent form with the survey, in accordance with procedures approved by the Institutional Review Board for the Protection of Human Subjects. Data Analysis All demographic data were analyzed using descriptive statistics. The WUSPI was scored by measuring the response on the VAS for each of the 15 items. The individual item scores were then summed to give a total score. We recorded how many subjects marked the option of “not performed” instead of a score on the VAS. Because many of the subjects with tetraplegia did not perform one or more activities measured in WUSPI items, we calculated a performancecorrected shoulder pain (PC-WUSPI) score by dividing the raw total WUSPI score by the number of activities performed and then multiplying by 15. In this way, we were able to more accurately reflect the actual intensity of shoulder pain experienced during activities performed, rather than assuming equivalent activity levels in subjects with tetraplegia and paraplegia. We also compared medical history characteristics and prevalence of shoulder pain in subjects with tetraplegia and subjects with paraplegia by conducting a series of x2 tests. Similarly, we performed a series of independent t tests to compare demographic characteristics and shoulder pain (PC-WUSPI) scores in the two groups. We then partitioned the two groups of subjects in three categories by age and years of wheelchair use and performed a Arch
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two-factor analysis of variance (ANOVA) to investigate the effect of the variables age and level of SC1 on shoulder pain (PC-WUSPI) scores. We performed an additional two-factor ANOVA to determine the effect of duration of wheelchair use and level of SC1 on shoulder pain (PC-WUSPI) scores. An alpha level of .05 was selected for all analyses. RESULTS Level of Daily Activity/Medical History Of the 700 individuals who were sent the questionnaire packet, 195 returned the survey (28%). Independent t tests showed no significant differences in age, years of wheelchair use, and weekly hours of work, school, or leisure activity between subjects with tetraplegia and subjects with paraplegia. Individuals with paraplegia, however, performed significantly more wheelchair transfers per day and spent significantly more hours per week driving than did individuals with tetraplegia (table 1). Chi-square analysis showed no significant differences in marital status or employment patterns between these two groups. There were, however, significant differences between the two groups with respect to gender; the proportion of women was greater among the paraplegic respondents (33%) than among the tetraplegic respondents (23%). Additionally, significantly more subjects with tetraplegia reported using power wheelchairs and vans with hydraulic lifts than did subjects with paraplegia. Further, only 54.4% of respondents with tetraplegia reported driving, compared with 86% of respondents with paraplegia (table 2). Less than 15% of the total subject pool reported that they had experienced shoulder pain before becoming wheelchair users. In contrast, 78% of subjects with tetraplegia and 59% of subjects with paraplegia reported that they had experienced shoulder pain since becoming wheelchair users. Similarly, 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reported current shoulder pain. More than 47% of the subjects with tetraplegia and 34% of the subjects with paraplegia reported that they had experienced bilateral shoulder pain. Chi-square analysis showed a significantly higher prevalence of previous shoulder pain, bilateral shoulder pain, and current shoulder pain in subjects with tetraplegia than in subjects with paraplegia. Despite the high prevalence of shoulder pain, fewer than 5% of individuals from either of the SC1 groups reported surgical intervention. In addition to shoulder pain, 43% of all subjects also reported a history of hand and elbow pain since becoming wheelchair users (table 3).
Table 1: Comparisons of Subjects With Tetraplegia and Paraplegia on Age, Exposure, and Activity Characteristics by Unpaired tTests Tetraplegia (n = 92)
Age Years of wheelchair use Average number of wheelchair transfers/day Hours/week Hours/weekof Hours/week * Indicates gia.
of work and school sport and leisure of driving that
value
is significantly
Paraplegia (n=103)
p
Meall
SD
Mean
SD
V&X?
32.9
10.0
34.4
10.7
NS
7.0
5.0
7.3
6.5
NS
7.1 20.8 14.0
5.5 19.8 14.8
17.0 23.4 13.6
10.1 17.4 14.0
<.001* NS
5.6
8.9
9.5
8.1
NS <.Ol*
in subjects
with
paraple-
higher
SHOULDER
Table
2: Comparisons of Subjects With by x2 Analyses on Demographic
PAIN
Tetraplegia and Characteristics
Tetraplegia (n = 92)
Paraplegia (n = 103)
n
%
”
71 21
77.2 22.8
69
67
34
33
56
61.5
42
41.4
26
28.6
46
44.7
7 2
7.7 2.2
11 30
10.7 2.9
0
0.0
1
1.0
Manual Power
53 7
57.6
98.1
Both
32
7.0 34.8
102 1
SCI lesion Complete
27
%
Gender
Paraplegia
pValue NS
Men Women Marital Status Single
NS
Married Divorced Separated Widowed Wheelchair
Type
<.OOl
1
1.0 1.0
32.1
39
43.3
51 6
60.7 7.1
36 15
40.0 16.7
26
28.3
42
40.8
Student Volunteer
25 5
27.2 5.4
25 2
24.3 1.9
Retired Other
14
15.2
13
12.6
22
23.9
21
20.3
50
54.4
42
45.7
89 14
86.4 13.6
co1
Incomplete Not known Employment Employed
Status
Driving Yes Vehicle Type Car Van with lift Van without or utility
vehicle
Curtis
455
Comparison of Shoulder Pain by Years of Exposure The subject pool was partitioned into three age groups: 30 years or younger, 31 to 40 years, and older than 40 years. A two-factor ANOVA was performed on shoulder pain (PCWUSPI) scores to determine the effect of age group and SC1 level on shoulder pain. We found a significant main effect of SC1 level, but no effect of age group and no significant interaction of the two factors. Individuals with tetraplegia showed higher PC-WUSPI scores in each age group, although the differences seem to grow much smaller in those subjects older than 40 years of age (fig 1). A similar two-factor ANOVA was done to determine the effect of duration of wheelchair use and SC1 level on shoulder pain (PC-WUSPI) scores. We partitioned the group into three categories: 0 to 5 years, 6 to 10 years, and more than 10 years of wheelchair use. Likewise, we found a significant main effect of SC1 level on PC-WUSPI scores but no effect of years of wheelchair use and no significant interaction of the two factors. Scoresfor subjects with paraplegia remained relatively constant in each duration of wheelchair use category. In contrast, shoulder pain (PC-WUSPI) scores for subjects with tetraplegia decreased with increased duration of wheelchair use (fig 2). Table
19
21.1
64
62.7
26 0
28.9 0.0
7 5
6.9 4.9
4 2
4.4 2.2
12 2
11.8 2.0
3: Comparisons by x2 Analyses
of Subjects With Tetraplegia and Paraplegia on History of Shoulder Pain and Treatment Tetraplegia (n = 92)
n Shoulder
becoming
wheelchair
user
p
(n=103)
%
”
%
Value
17
18.5
8
7.8
<.05+
72 54
78.3 58.7
61 43
59.2 41.7
<.05+ <.05+
13
14.6
11
11.0
+
15 42 19
16.9 47.2 21.4
13 34 42
13.0 34.0 42.0
+ + *
4
4.4
3
2.9
NS
33
35.9
24
23.5
NS
Physical Therapist Chiropractor
28 4 1
30.8 4.4 1.1
16 6
15.7 5.9
Other None
1
11.1
4
3.9
57
62.6
76
74.5
Since becoming wheelchair user Current pain Location of shoulder pain since becoming
wheelchair
user
1.05
Left Right Bilateral None History
WUSPI Scores We calculated the PC-WUSPI score by dividing the raw total WUSPI score by the number of activities performed and then multiplying by 15. The PC-WUSPI scores for the group of subjects with tetraplegia were 70% higher (29.4) than the PC-WUSPI scores for the group of subjects with paraplegia (17.3). Further, the intensity of shoulder pain was even higher in subjects with tetraplegia who reported bilateral shoulder pain. Among respondents who reported bilateral pain, PC-WUSPI scores averaged 58 points in subjects with tetraplegia and 31 points in those with paraplegia, reflecting an almost 90% higher average intensity of shoulder pain in subjects with tetraplegia. There was little difference, however, between individuals with tetraplegia and individuals with paraplegia in the rank order of the activities they found most painful. Both SC1 groups reported the highest intensities of shoulder pain while pushing the wheelchair up an incline, while pushing the wheelchair for more than 10 minutes, and while sleeping. Comparison of individual WUSPI item scores in subjects with tetraplegia and subjects with paraplegia by independent t tests showed that those with tetraplegia had significantly higher scores than did those with paraplegia for three individual items-pushing wheelchairs up ramps/inclines, putting on a T shirt/pullover, and driving (table 4).
Paraplegia
Pain
Before <.OOl
lift
USERS,
NS
1.001
No
Truck Other
IN WHEELCHAIR
of shoulder
Has sought shoulder
surgery
medical pain
Medical attention provided by:
attention
for
for shoulder
pain NS
Physician
Treatment Ice
for shoulder
pain
Heat Exercise Medication Rest Presence
of hand/elbow
23.9
23
22.3
NS
38.0 44.6
26 31
25.2 30.1
<.05+ <.05+
33 45
35.9 48.9
25 38
24.3 36.9
NS NS
36
40.0
46
45.1
NS
13 7
14.6 7.9
10 11
9.7 10.7
16 53
18.0 59.6
26 55
25.2 45.4
pain since
becoming wheelchair Location of hand/elbow
user pain
NS
Left Right Bilateral None * Indicates gia. + Indicates gia.
22 35 41
that
score
is significantly
higher
in subjects
with
paraple-
that
score
is significantly
higher
in subjects
with
tetraple-
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SHOULDER
Table
4: Unpaired
t Tests Comparing WUSPI Scores With Tetraplegia and Paraplegia Tetraplegia
PAIN
IN WHEELCHAIR
USERS,
Curtis
of Subjects
Paraplegia P
(ofk!)
Mean
SD
(of?CJS)
Mean
SD
Values
transfer Wheelchair-car
81
1.2
2.0
101
0.8
1.6
NS
transfer Wheelchair-tub
53
1.3
2.4
100
1.0
1.8
NS
61
1.5
2.4
99
1.0
1.8
NS
27
0.9
1.8
87
1.5
2.3
NS
74
2.6
3.3
97
1.9
2.7
NS
65
3.0
3.4
98
1.8
2.6
overhead Putting on pants Putting on
58 48
1.7 0.9
2.9 1.7
98 100
1.5 0.6
2.4 1.4
t-shirt/pullover Putting on button-
71
1.4
2.4
101
0.7
1.5
48 47
0.9
2.1
96
0.6
1.3
NS
1.3
2.4
99
1.0
1.9
NS
WUSPI
Items
Bed-wheelchair
transfer Loading wheelchair into car Pushing
wheelchair
>lOmin Pushing wheelchair up ramps/inclines Lifting
object
down
shirt
Washing back Daily activities
chores
* Indicates gia. + Indicates gia.
2.1
2.7
99
1.3
2.2
NS
46
2.2 1.2
3.1 2.2
91 96
1.0 1.2
1.7 2.1
<.01+ NS
2.3
2.8
100
1.7
2.6
NS
9.7 29.4
4.4 36.6
92 103
14.2 17.5
2.2 24.5
<.OOl* <.Ol’
92 score
92
that
score
is significantly
higher
in subjects
with
paraple-
that
score
is significantly
higher
in subjects
with
tetraple-
DISCUSSION Few studies have documented the prevalence or intensity of shoulder pain in wheelchair users during specific functional activities. Sie and associates3compared the overall prevalence of upper extremity pain in SCI, but focused on locations of pain
Fig 1. Comparison of shoulder pain scores in subjects with tetraplegia and paraplegia by age group. Among subjects with paraplegia WUSPI scores increased in each age decile. In comparison, among subjects with tetraplegia, scores were markedly higher in each decile except that of subjects older than 40 years.
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6-10 YEARS YEARS OF WHEELCHAIR USE
210 YEARS
Fig 2. Comparison of shoulder pain scores in subjects with tetraplegia and paraplegia by duration of wheelchair use. Subjects with paraplegia had similar WUSPI scores across all exposures to wheelchair use. In comparison, scores of individuals with tetraplegia decreased in each 5-year interval.
4.05’
70 62 83
Total items performed PC-WUSPI
NS NS
at
work/school Driving Household Sleeping
<.Ol+
from
o-5 YRS
in general anatomic regions of the upper extremities rather than the activities that elicited pain. Silfverskiold and Waters14 reported that 33% of subjects with tetraplegia 6 to 18 months after onset of SC1 experienced moderate to severe functional disability, whereas subjects with paraplegia experienced minimal functional lossesdue to shoulder pain. In the current cross-sectional study, both the prevalence and intensity of shoulder pain during the performance of functional activities was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Individuals with tetraplegia can be at a slight to severe disadvantage in performing activities of daily living because they may lack strong elbow extension, precise hand grip, and trunk stability.15 With the high prevalence of shoulder pain and generally lower reported frequency of performance, we concluded that some individuals with tetraplegia may find routine transfers, extended periods of wheelchair propulsion, or other activities of daily living either too painful or too strenuous and, therefore, cease to routinely perform these activities. Another important issue is the intensity of shoulder pain that subjects in both SC1 groups reported during sleeping hours. Scott and Donovani reported that nearly half of their subjects with tetraplegia experienced shoulder pain severe enough to interfere with sleep. Likewise, Silfverskiold and Waters14 reported that many patients with tetraplegia experienced shoulder pain day and night. Our study supports these findings in that 46% of individuals with paraplegia and 60% of individuals with tetraplegia reported pain during sleeping hours. The etiology of shoulder pain in this population has also received considerable attention in the literature. Researchers have associated shoulder pain in the SC1 population with overuse related to weight-bearing during wheelchair transfers and excessive demands of wheelchair propulsion.5,6,10,17,18 It would be expected that shoulder pain associated with overuse should increase with years of exposure, either with increased age or with increased years of wheelchair use. Pentland and Twomeyll concluded that upper limb pain in individuals with paraplegia increases over time. Similarly, Sie and colleagues2 reported that individuals with paraplegia experienced an increase in prevalence of upper extremity pain between 5 and 20 years after injury. In our study, both subjects with tetraplegia and those with paraplegia showed increasing WUSPI scores with increasing age, although WUSPI scores of subjects with
SHOULDER
PAIN
IN WHEELCHAIR
tetraplegia older than 40 years of age were lower than the scores of subjects with tetraplegia who were in the 31- to 40-year-old age group. This difference may be in part due to the nonperformance of painful activities in the aging individual with tetraplegia. Subjects with paraplegia performed most of the activities measured by the WUSPI across all age groups. In contrast, subjects with tetraplegia decreased activity performance as age increased. Even with the calculation of the PC-WUSPI score, nonperformance of the most painful activities will tend to lower scores for this subgroup of wheelchair users in comparison to those in younger age brackets. Similarly, in the current study, individuals with tetraplegia with 0 to 5 years of wheelchair use reported the highest shoulder pain (PC-WUSPI) scores in comparison with two subgroups with greater durations of wheelchair use. Again, these lower scores may indicate less intensity of shoulder pain, but are more likely to reflect nonperformance of the most painful activities in the two subgroups with tetraplegia with greater durations of wheelchair use. Limitations
of Study
This cross-sectional study is limited in that it measures the subjects’ shoulder pain at one point in time. Because of the nature of this design, we are unable to draw conclusions about whether the intensity of shoulder pain was stable, decreasing, or increasing over time in an individual subject. Additionally, the study had a response rate of only 28% in a sample of fairly young individuals with SCI. Because the sample was limited in both size and range of age, it may not be generalizable to the SC1population as a whole. Recommendations
for Future
Research
We recommend a longitudinal study be conducted using the WUSPI on a broader range of the population with SCI, representing a greater variation in age and years of wheelchair use. Further clinical research also needs to be focused on the development of strategies that prevent and decrease the prevalence and/or intensity of chronic upper extremity pain in this population. CONCLUSION
This study documents a strong influence of shoulder pain on the performance of functional activities after SCI. The findings of this study supported previous reports that the prevalence and intensity of shoulder pain is higher in individuals with tetraplegia than in individuals with paraplegia. Individuals with tetraplegia were more likely to not perform the most strenuous functional activities with increasing age or duration of wheelchair use. The WUSPI seems to measure shoulder pain well in subjects with tetraplegia if information
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regarding nonperformance of particular items is simultaneously collected to allow computation of performance-corrected scores. Acknowledgments: The authorsacknowledgethe Miami Project to Cure Paralysis for assistance in subject recruitment and the Ronald E. McNair Post-baccalaureate Achievement Program for its support in manuscript preparation. References 1. Collins WE. A review and update of experimental and clinical studies of spinal cord injury. Paraplegia 1983;21:204-19. 2. Sie IH, Waters RL, Adkins RH, Gellman H. Upper extremity pain in the postrehabilitation spinal cord injured patient. Arch Phys Med Rehabil 1992;73:44-8. 3. Pentland WE, Twomey LT. The weight-bearing upper extremity in women with long term paraplegia. Paraplegia 1991;29:521-30. 4. Geisler WO, Jousse AT, Wynne-Jones M, Breithaupt D. Survival in traumatic spinal cord injury. Paraplegia 1983;21:364-73. 5. Gellman H, Sie I, Waters RL. Late complications of the weightbearing upper extremity in the paraplegic patient. Clin Orthop 1988;233:132-5. 6. Nichols PJR, Norman PA, Ennis JR. Wheelchair user’s shoulder? Stand J Rehabil Med 1979;11:29-32. 7. Waring WP, Maynard FM. Shoulder pain in acute traumatic quadriplegia. Paraplegia 1991;29:37-42. 8. Robinson MD, Hussey RW, Ha CY. Surgical decompression of impingement in the weight-bearing shoulder. Arch Phys Med Rehabil 1993;74:324-7. 9. Curtis KA, Dillon DA. Survey of wheelchair athletic injuries: common patterns and prevention. Paraplegia 1985;23:70-5. 10. Bayley JC, Cochran TP, Sledge CB. The weight-bearing shoulder. J Bone Joint Surg 1987;69A:676-8. 11. Pentland WE. Twomev LT. Uaoer limb function in versons with long term paraplegia and impikations for independence: part II. Paraplegia 1994;32:219-24. 12. Curtis KA, Roach KE, Applegate EB, Amar T, Benbow CS, Genecco TD, et al. Development of the wheelchair user’s shoulder pain index (WUSPI). Paraplegia 1995;33:290-93. 13. Curtis KA, Roach KE, Applegate EB, Amar T, Benbow CS, Genecco TD. et al. Reliabilitv and validitv of the wheelchair user’s shoulder pain index (WUSPI). Paraplegia 1995;33:595-601. 14. Silfverskiold J, Waters RL. Shoulder pain and functional disability in spinal cord injury patients. Clin Orthop 1991;272:141-5. 15. Harburn KL, Spaulding SJ. Muscle activity in the spinal cordinjured during wheelchair ambulation. Am J Occup Ther 1986;40: 629-36. 16. Scott JA, Donovan WH. The prevention of shoulder pain and contracture in the acute quadriplegia patient. Paraplegia 198 1; 19: 313-9. 17. Barber DB, Gail NG. Osteonecrosis: an overuse injury of the shoulder in paraplegia: a case report. Paraplegia 1991;29:423-6. 18. Powers MC, Newsam CJ, Gronley JK, Fontaine CA, Perry .I. Isometric shoulder torque in subjects with spinal cord injury. Arch Phys Med Rehabil 1994;75:761-5.
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Shoulder Pain in Wheelchair Users With Tetraplegia and Paraplegia Kathleen A. Curtis. PhD. PT. George A. Drvsdale. BS. R. David Lunza, MSPT, Morey Kolber, MSPT, Richard S. Vitolo, kSP$ Rdnald 6’est, M,$PT ’ ’ ABSTRACT. Curtis KA, Drysdale GA, Lanza RD, Kolber M, Vitolo RS, West R. Shoulder pain in wheelchair users with tetraplegia and paraplegia. Arch Phys Med Rehabil 1999;80: 453-7. Objective: To compare the prevalence and intensity of shoulder pain experienced during daily functional activities in individuals with tetraplegia and individuals with paraplegia who use manual wheelchairs. Design: Self-report survey. Setting: General community. Participants: Fifty-five women and 140 men, 92 subjects with tetraplegia and 103 subjects with paraplegia who met inclusion criteria of 3 hours per week of manual wheelchair use and at least 1 year since onset of spinal cord injury. Main Outcome Measures: Respondents completed a demographic and medical history questionnaire and the Wheelchair User’s Shoulder Pain Index (WUSPI), a measure of pain during typical daily activities. Results: More than two thirds of the sample reported shoulder pain since beginning wheelchair use, with 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reporting current pain. Performance-corrected WUSPI scoreswere significantly higher in subjects with tetraplegia than in subjects with paraplegia. Conclusions: Both the prevalence and intensity of shoulder pain was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Efforts to monitor and prevent shoulder pain should continue after rehabilitation. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation N THE UNITED STATES there are an estimated 235,000 to Iestimated 265,000 individuals with spinal cord injury (SCI) and an additional 9,000 new injuries each year1 ApproxiFrom the Division of Physical Therapy, Department of Orthopaedics and Rehabilitation, University of Miami School of Medicine, Miami, FL (Dr. Curtis, Mr. Lanza, Mr. Kolber, Mr. kolo, Mr. West): and the Department of Physical Therapy, School of Health and Human Services. California State Universitv. Fresno. CA (Mr. Drvsdalej. Dr. Curtis is currently affiliated with the Department o?‘Physical Theiapy, Slhool if Health and Human Services. California State University, Fresno, CA. Mr. Kolber is currently affiliated with Lighthouse Orthopedics, Boca Raton, FL. Mr. Lana is currently affiliated with Egan Health Care, Metairie, LA. Mr. West is currently afkiliated with the Public Health Service-Phoenix Indian Medical Center, Phoenix, AZ. Mr. Vitolo is currently affiliated with the Veterans Administration Medical Center, West Palm Beach, FL. Submitted for publication August 4, 1998. Accepted in revised form October 22, 1998. Presented at Physical Therapy 98, Scientific Meeting and Exposition, American Physical Therapy Association, June 7, 1998, Orlando. FL. 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 Kathleen A. Curtis, PhD, PT, Physical Therapy Department, California State University, Fresno, 2345 East San Ramon Avenue/MS 29, Fresno, CA 93740-8031. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation 0003-9993/99/X004-5152$3.00/0
mately 53% of these individuals have cervical lesions (tetraplegia); the remaining 47% have lesions below the first thoracic level (paraplegia). Although advances in technology and health care have increased the life expectancy of individuals with SCI, many quality-of-life issues have surfaced related to secondary disabilities associated with aging.2-5 Most individuals with paraplegia and tetraplegia use wheelchairs for mobility at home, school, work, and play. Many wheelchair users experience upper extremity pain that interferes with essential activities of daily living such as wheelchair propulsion, driving, dressing, and transfers6z7Upper extremity weight-bearing activities and chronic overuse have both been implicated in the development of soft tissue disorders and degenerative changes in the shoulder jointslo Although several studies have documented the prevalence of upper extremity pain in manual wheelchair users, few authors have addressed related functional difficulties. Pentland and Twomeyl’ documented the functional implications of shoulder pain in 11 women with paraplegia, and reported that work and school activities, outdoor wheeling, household work/child care, and loading a wheelchair into a car were most commonly associated with shoulder pain. Curtis and colleaguesI2 also studied 64 long-term wheelchair users with SC1 and reported the highest intensity of shoulder pain during functional activities requiring extremes of shoulder range of motion, overhead positioning, or a high level of upper extremity strength. The most painful activities for these subjects included wheeling up inclines, reaching to an overhead shelf, sleeping, transfers to nonlevel surfaces, and washing their backs. Since individuals with tetraplegia are generally more limited in upper extremity strength and function than are persons with paraplegia, we might expect that wheelchair users with tetraplegia would experience a higher prevalence and intensity of shoulder pain during functional activities than would wheelchair users with paraplegia. This was supported by Sie and associates2 who observed that significantly more individuals with tetraplegia than individuals with paraplegia reported that they had experienced shoulder pain since their SC1 (46% and 36%, respectively). Neither the intensity of shoulder pain nor the difficulty it imposes during functional activities has been compared in wheelchair users with respect to level of SCI. Identification of these problems in the SC1 population has implications for detection, prevention, and treatment of musculoskeletal complications and resulting secondary disability. Therefore, the purpose of the current study was to compare the prevalence and intensity of shoulder pain during specific functional activities in individuals with tetraplegia and individuals with paraplegia. METHODS Subjects Subjects included 195 individuals with SCI, 55 women and 140 men, who used manual wheelchairs for at least 3 hours a Arch
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SHOULDER
PAIN
IN WHEELCHAIR
week. There were 92 subjects with tetraplegia; their average age was 32.9 (i 10.1) years, they had used their wheelchairs an average of 6.9 (k5.0) years, and 55% were employed or students. In comparison, there were 103 subjects with paraplegia; their average age was 34.4 (t 10.7) years, they had used their wheelchairs an average of 7.2 (26.5) years, and 65% of this group were employed or students. Instrumentation A self-administered questionnaire was used to collect demographic and medical history information and to assess the intensity of pain experienced during the performance of activities of daily living. Data collected included age, gender, marital status, duration of wheelchair use, level of SCI, frequency of wheelchair transfers per day, hours per week spent at work and/or school, in sporting/recreational activities, and driving, type of automobile driven, history of shoulder problems, presence and location of current shoulder pain, type of medical attention sought for shoulder pain, type of treatment received for shoulder pain, and presence of other upper extremity pain. We used the Wheelchair User’s Shoulder Pain Index (WUSPI), a 15-item valid and reliable questionnaire, to assess the intensity of pain during the performance of activities of daily living such as transfers, loading a wheelchair into a car, wheeling up inclines, dressing, bathing, overhead lifting, driving, performing household chores, and sleeping.13 Subjects rated their intensity of pain during these activities on a lo-cm visual analog scale (VAS) anchored at “no pain” and “worst pain ever experienced.” The total possible score on the scale ranged from 0 to 150. Procedures A packet, including a cover letter, consent form, questionnaire, and return mail envelope, was mailed to 700 individuals with SC1 who were registered with an SC1 research foundation. A follow-up postcard was mailed 3 weeks after the initial mailing to encourage a prompt response. Subjects returned a signed consent form with the survey, in accordance with procedures approved by the Institutional Review Board for the Protection of Human Subjects. Data Analysis All demographic data were analyzed using descriptive statistics. The WUSPI was scored by measuring the response on the VAS for each of the 15 items. The individual item scores were then summed to give a total score. We recorded how many subjects marked the option of “not performed” instead of a score on the VAS. Because many of the subjects with tetraplegia did not perform one or more activities measured in WUSPI items, we calculated a performancecorrected shoulder pain (PC-WUSPI) score by dividing the raw total WUSPI score by the number of activities performed and then multiplying by 15. In this way, we were able to more accurately reflect the actual intensity of shoulder pain experienced during activities performed, rather than assuming equivalent activity levels in subjects with tetraplegia and paraplegia. We also compared medical history characteristics and prevalence of shoulder pain in subjects with tetraplegia and subjects with paraplegia by conducting a series of x2 tests. Similarly, we performed a series of independent t tests to compare demographic characteristics and shoulder pain (PC-WUSPI) scores in the two groups. We then partitioned the two groups of subjects in three categories by age and years of wheelchair use and performed a Arch
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Curtis
two-factor analysis of variance (ANOVA) to investigate the effect of the variables age and level of SC1 on shoulder pain (PC-WUSPI) scores. We performed an additional two-factor ANOVA to determine the effect of duration of wheelchair use and level of SC1 on shoulder pain (PC-WUSPI) scores. An alpha level of .05 was selected for all analyses. RESULTS Level of Daily Activity/Medical History Of the 700 individuals who were sent the questionnaire packet, 195 returned the survey (28%). Independent t tests showed no significant differences in age, years of wheelchair use, and weekly hours of work, school, or leisure activity between subjects with tetraplegia and subjects with paraplegia. Individuals with paraplegia, however, performed significantly more wheelchair transfers per day and spent significantly more hours per week driving than did individuals with tetraplegia (table 1). Chi-square analysis showed no significant differences in marital status or employment patterns between these two groups. There were, however, significant differences between the two groups with respect to gender; the proportion of women was greater among the paraplegic respondents (33%) than among the tetraplegic respondents (23%). Additionally, significantly more subjects with tetraplegia reported using power wheelchairs and vans with hydraulic lifts than did subjects with paraplegia. Further, only 54.4% of respondents with tetraplegia reported driving, compared with 86% of respondents with paraplegia (table 2). Less than 15% of the total subject pool reported that they had experienced shoulder pain before becoming wheelchair users. In contrast, 78% of subjects with tetraplegia and 59% of subjects with paraplegia reported that they had experienced shoulder pain since becoming wheelchair users. Similarly, 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reported current shoulder pain. More than 47% of the subjects with tetraplegia and 34% of the subjects with paraplegia reported that they had experienced bilateral shoulder pain. Chi-square analysis showed a significantly higher prevalence of previous shoulder pain, bilateral shoulder pain, and current shoulder pain in subjects with tetraplegia than in subjects with paraplegia. Despite the high prevalence of shoulder pain, fewer than 5% of individuals from either of the SC1 groups reported surgical intervention. In addition to shoulder pain, 43% of all subjects also reported a history of hand and elbow pain since becoming wheelchair users (table 3).
Table 1: Comparisons of Subjects With Tetraplegia and Paraplegia on Age, Exposure, and Activity Characteristics by Unpaired tTests Tetraplegia (n = 92)
Age Years of wheelchair use Average number of wheelchair transfers/day Hours/week Hours/weekof Hours/week * Indicates gia.
of work and school sport and leisure of driving that
value
is significantly
Paraplegia (n=103)
p
Meall
SD
Mean
SD
V&X?
32.9
10.0
34.4
10.7
NS
7.0
5.0
7.3
6.5
NS
7.1 20.8 14.0
5.5 19.8 14.8
17.0 23.4 13.6
10.1 17.4 14.0
<.001* NS
5.6
8.9
9.5
8.1
NS <.Ol*
in subjects
with
paraple-
higher
SHOULDER
Table
2: Comparisons of Subjects With by x2 Analyses on Demographic
PAIN
Tetraplegia and Characteristics
Tetraplegia (n = 92)
Paraplegia (n = 103)
n
%
”
71 21
77.2 22.8
69
67
34
33
56
61.5
42
41.4
26
28.6
46
44.7
7 2
7.7 2.2
11 30
10.7 2.9
0
0.0
1
1.0
Manual Power
53 7
57.6
98.1
Both
32
7.0 34.8
102 1
SCI lesion Complete
27
%
Gender
Paraplegia
pValue NS
Men Women Marital Status Single
NS
Married Divorced Separated Widowed Wheelchair
Type
<.OOl
1
1.0 1.0
32.1
39
43.3
51 6
60.7 7.1
36 15
40.0 16.7
26
28.3
42
40.8
Student Volunteer
25 5
27.2 5.4
25 2
24.3 1.9
Retired Other
14
15.2
13
12.6
22
23.9
21
20.3
50
54.4
42
45.7
89 14
86.4 13.6
co1
Incomplete Not known Employment Employed
Status
Driving Yes Vehicle Type Car Van with lift Van without or utility
vehicle
Curtis
455
Comparison of Shoulder Pain by Years of Exposure The subject pool was partitioned into three age groups: 30 years or younger, 31 to 40 years, and older than 40 years. A two-factor ANOVA was performed on shoulder pain (PCWUSPI) scores to determine the effect of age group and SC1 level on shoulder pain. We found a significant main effect of SC1 level, but no effect of age group and no significant interaction of the two factors. Individuals with tetraplegia showed higher PC-WUSPI scores in each age group, although the differences seem to grow much smaller in those subjects older than 40 years of age (fig 1). A similar two-factor ANOVA was done to determine the effect of duration of wheelchair use and SC1 level on shoulder pain (PC-WUSPI) scores. We partitioned the group into three categories: 0 to 5 years, 6 to 10 years, and more than 10 years of wheelchair use. Likewise, we found a significant main effect of SC1 level on PC-WUSPI scores but no effect of years of wheelchair use and no significant interaction of the two factors. Scoresfor subjects with paraplegia remained relatively constant in each duration of wheelchair use category. In contrast, shoulder pain (PC-WUSPI) scores for subjects with tetraplegia decreased with increased duration of wheelchair use (fig 2). Table
19
21.1
64
62.7
26 0
28.9 0.0
7 5
6.9 4.9
4 2
4.4 2.2
12 2
11.8 2.0
3: Comparisons by x2 Analyses
of Subjects With Tetraplegia and Paraplegia on History of Shoulder Pain and Treatment Tetraplegia (n = 92)
n Shoulder
becoming
wheelchair
user
p
(n=103)
%
”
%
Value
17
18.5
8
7.8
<.05+
72 54
78.3 58.7
61 43
59.2 41.7
<.05+ <.05+
13
14.6
11
11.0
+
15 42 19
16.9 47.2 21.4
13 34 42
13.0 34.0 42.0
+ + *
4
4.4
3
2.9
NS
33
35.9
24
23.5
NS
Physical Therapist Chiropractor
28 4 1
30.8 4.4 1.1
16 6
15.7 5.9
Other None
1
11.1
4
3.9
57
62.6
76
74.5
Since becoming wheelchair user Current pain Location of shoulder pain since becoming
wheelchair
user
1.05
Left Right Bilateral None History
WUSPI Scores We calculated the PC-WUSPI score by dividing the raw total WUSPI score by the number of activities performed and then multiplying by 15. The PC-WUSPI scores for the group of subjects with tetraplegia were 70% higher (29.4) than the PC-WUSPI scores for the group of subjects with paraplegia (17.3). Further, the intensity of shoulder pain was even higher in subjects with tetraplegia who reported bilateral shoulder pain. Among respondents who reported bilateral pain, PC-WUSPI scores averaged 58 points in subjects with tetraplegia and 31 points in those with paraplegia, reflecting an almost 90% higher average intensity of shoulder pain in subjects with tetraplegia. There was little difference, however, between individuals with tetraplegia and individuals with paraplegia in the rank order of the activities they found most painful. Both SC1 groups reported the highest intensities of shoulder pain while pushing the wheelchair up an incline, while pushing the wheelchair for more than 10 minutes, and while sleeping. Comparison of individual WUSPI item scores in subjects with tetraplegia and subjects with paraplegia by independent t tests showed that those with tetraplegia had significantly higher scores than did those with paraplegia for three individual items-pushing wheelchairs up ramps/inclines, putting on a T shirt/pullover, and driving (table 4).
Paraplegia
Pain
Before <.OOl
lift
USERS,
NS
1.001
No
Truck Other
IN WHEELCHAIR
of shoulder
Has sought shoulder
surgery
medical pain
Medical attention provided by:
attention
for
for shoulder
pain NS
Physician
Treatment Ice
for shoulder
pain
Heat Exercise Medication Rest Presence
of hand/elbow
23.9
23
22.3
NS
38.0 44.6
26 31
25.2 30.1
<.05+ <.05+
33 45
35.9 48.9
25 38
24.3 36.9
NS NS
36
40.0
46
45.1
NS
13 7
14.6 7.9
10 11
9.7 10.7
16 53
18.0 59.6
26 55
25.2 45.4
pain since
becoming wheelchair Location of hand/elbow
user pain
NS
Left Right Bilateral None * Indicates gia. + Indicates gia.
22 35 41
that
score
is significantly
higher
in subjects
with
paraple-
that
score
is significantly
higher
in subjects
with
tetraple-
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SHOULDER
Table
4: Unpaired
t Tests Comparing WUSPI Scores With Tetraplegia and Paraplegia Tetraplegia
PAIN
IN WHEELCHAIR
USERS,
Curtis
of Subjects
Paraplegia P
(ofk!)
Mean
SD
(of?CJS)
Mean
SD
Values
transfer Wheelchair-car
81
1.2
2.0
101
0.8
1.6
NS
transfer Wheelchair-tub
53
1.3
2.4
100
1.0
1.8
NS
61
1.5
2.4
99
1.0
1.8
NS
27
0.9
1.8
87
1.5
2.3
NS
74
2.6
3.3
97
1.9
2.7
NS
65
3.0
3.4
98
1.8
2.6
overhead Putting on pants Putting on
58 48
1.7 0.9
2.9 1.7
98 100
1.5 0.6
2.4 1.4
t-shirt/pullover Putting on button-
71
1.4
2.4
101
0.7
1.5
48 47
0.9
2.1
96
0.6
1.3
NS
1.3
2.4
99
1.0
1.9
NS
WUSPI
Items
Bed-wheelchair
transfer Loading wheelchair into car Pushing
wheelchair
>lOmin Pushing wheelchair up ramps/inclines Lifting
object
down
shirt
Washing back Daily activities
chores
* Indicates gia. + Indicates gia.
2.1
2.7
99
1.3
2.2
NS
46
2.2 1.2
3.1 2.2
91 96
1.0 1.2
1.7 2.1
<.01+ NS
2.3
2.8
100
1.7
2.6
NS
9.7 29.4
4.4 36.6
92 103
14.2 17.5
2.2 24.5
<.OOl* <.Ol’
92 score
92
that
score
is significantly
higher
in subjects
with
paraple-
that
score
is significantly
higher
in subjects
with
tetraple-
DISCUSSION Few studies have documented the prevalence or intensity of shoulder pain in wheelchair users during specific functional activities. Sie and associates3compared the overall prevalence of upper extremity pain in SCI, but focused on locations of pain
Fig 1. Comparison of shoulder pain scores in subjects with tetraplegia and paraplegia by age group. Among subjects with paraplegia WUSPI scores increased in each age decile. In comparison, among subjects with tetraplegia, scores were markedly higher in each decile except that of subjects older than 40 years.
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6-10 YEARS YEARS OF WHEELCHAIR USE
210 YEARS
Fig 2. Comparison of shoulder pain scores in subjects with tetraplegia and paraplegia by duration of wheelchair use. Subjects with paraplegia had similar WUSPI scores across all exposures to wheelchair use. In comparison, scores of individuals with tetraplegia decreased in each 5-year interval.
4.05’
70 62 83
Total items performed PC-WUSPI
NS NS
at
work/school Driving Household Sleeping
<.Ol+
from
o-5 YRS
in general anatomic regions of the upper extremities rather than the activities that elicited pain. Silfverskiold and Waters14 reported that 33% of subjects with tetraplegia 6 to 18 months after onset of SC1 experienced moderate to severe functional disability, whereas subjects with paraplegia experienced minimal functional lossesdue to shoulder pain. In the current cross-sectional study, both the prevalence and intensity of shoulder pain during the performance of functional activities was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Individuals with tetraplegia can be at a slight to severe disadvantage in performing activities of daily living because they may lack strong elbow extension, precise hand grip, and trunk stability.15 With the high prevalence of shoulder pain and generally lower reported frequency of performance, we concluded that some individuals with tetraplegia may find routine transfers, extended periods of wheelchair propulsion, or other activities of daily living either too painful or too strenuous and, therefore, cease to routinely perform these activities. Another important issue is the intensity of shoulder pain that subjects in both SC1 groups reported during sleeping hours. Scott and Donovani reported that nearly half of their subjects with tetraplegia experienced shoulder pain severe enough to interfere with sleep. Likewise, Silfverskiold and Waters14 reported that many patients with tetraplegia experienced shoulder pain day and night. Our study supports these findings in that 46% of individuals with paraplegia and 60% of individuals with tetraplegia reported pain during sleeping hours. The etiology of shoulder pain in this population has also received considerable attention in the literature. Researchers have associated shoulder pain in the SC1 population with overuse related to weight-bearing during wheelchair transfers and excessive demands of wheelchair propulsion.5,6,10,17,18 It would be expected that shoulder pain associated with overuse should increase with years of exposure, either with increased age or with increased years of wheelchair use. Pentland and Twomeyll concluded that upper limb pain in individuals with paraplegia increases over time. Similarly, Sie and colleagues2 reported that individuals with paraplegia experienced an increase in prevalence of upper extremity pain between 5 and 20 years after injury. In our study, both subjects with tetraplegia and those with paraplegia showed increasing WUSPI scores with increasing age, although WUSPI scores of subjects with
SHOULDER
PAIN
IN WHEELCHAIR
tetraplegia older than 40 years of age were lower than the scores of subjects with tetraplegia who were in the 31- to 40-year-old age group. This difference may be in part due to the nonperformance of painful activities in the aging individual with tetraplegia. Subjects with paraplegia performed most of the activities measured by the WUSPI across all age groups. In contrast, subjects with tetraplegia decreased activity performance as age increased. Even with the calculation of the PC-WUSPI score, nonperformance of the most painful activities will tend to lower scores for this subgroup of wheelchair users in comparison to those in younger age brackets. Similarly, in the current study, individuals with tetraplegia with 0 to 5 years of wheelchair use reported the highest shoulder pain (PC-WUSPI) scores in comparison with two subgroups with greater durations of wheelchair use. Again, these lower scores may indicate less intensity of shoulder pain, but are more likely to reflect nonperformance of the most painful activities in the two subgroups with tetraplegia with greater durations of wheelchair use. Limitations
of Study
This cross-sectional study is limited in that it measures the subjects’ shoulder pain at one point in time. Because of the nature of this design, we are unable to draw conclusions about whether the intensity of shoulder pain was stable, decreasing, or increasing over time in an individual subject. Additionally, the study had a response rate of only 28% in a sample of fairly young individuals with SCI. Because the sample was limited in both size and range of age, it may not be generalizable to the SC1population as a whole. Recommendations
for Future
Research
We recommend a longitudinal study be conducted using the WUSPI on a broader range of the population with SCI, representing a greater variation in age and years of wheelchair use. Further clinical research also needs to be focused on the development of strategies that prevent and decrease the prevalence and/or intensity of chronic upper extremity pain in this population. CONCLUSION
This study documents a strong influence of shoulder pain on the performance of functional activities after SCI. The findings of this study supported previous reports that the prevalence and intensity of shoulder pain is higher in individuals with tetraplegia than in individuals with paraplegia. Individuals with tetraplegia were more likely to not perform the most strenuous functional activities with increasing age or duration of wheelchair use. The WUSPI seems to measure shoulder pain well in subjects with tetraplegia if information
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regarding nonperformance of particular items is simultaneously collected to allow computation of performance-corrected scores. Acknowledgments: The authorsacknowledgethe Miami Project to Cure Paralysis for assistance in subject recruitment and the Ronald E. McNair Post-baccalaureate Achievement Program for its support in manuscript preparation. References 1. Collins WE. A review and update of experimental and clinical studies of spinal cord injury. Paraplegia 1983;21:204-19. 2. Sie IH, Waters RL, Adkins RH, Gellman H. Upper extremity pain in the postrehabilitation spinal cord injured patient. Arch Phys Med Rehabil 1992;73:44-8. 3. Pentland WE, Twomey LT. The weight-bearing upper extremity in women with long term paraplegia. Paraplegia 1991;29:521-30. 4. Geisler WO, Jousse AT, Wynne-Jones M, Breithaupt D. Survival in traumatic spinal cord injury. Paraplegia 1983;21:364-73. 5. Gellman H, Sie I, Waters RL. Late complications of the weightbearing upper extremity in the paraplegic patient. Clin Orthop 1988;233:132-5. 6. Nichols PJR, Norman PA, Ennis JR. Wheelchair user’s shoulder? Stand J Rehabil Med 1979;11:29-32. 7. Waring WP, Maynard FM. Shoulder pain in acute traumatic quadriplegia. Paraplegia 1991;29:37-42. 8. Robinson MD, Hussey RW, Ha CY. Surgical decompression of impingement in the weight-bearing shoulder. Arch Phys Med Rehabil 1993;74:324-7. 9. Curtis KA, Dillon DA. Survey of wheelchair athletic injuries: common patterns and prevention. Paraplegia 1985;23:70-5. 10. Bayley JC, Cochran TP, Sledge CB. The weight-bearing shoulder. J Bone Joint Surg 1987;69A:676-8. 11. Pentland WE. Twomev LT. Uaoer limb function in versons with long term paraplegia and impikations for independence: part II. Paraplegia 1994;32:219-24. 12. Curtis KA, Roach KE, Applegate EB, Amar T, Benbow CS, Genecco TD, et al. Development of the wheelchair user’s shoulder pain index (WUSPI). Paraplegia 1995;33:290-93. 13. Curtis KA, Roach KE, Applegate EB, Amar T, Benbow CS, Genecco TD. et al. Reliabilitv and validitv of the wheelchair user’s shoulder pain index (WUSPI). Paraplegia 1995;33:595-601. 14. Silfverskiold J, Waters RL. Shoulder pain and functional disability in spinal cord injury patients. Clin Orthop 1991;272:141-5. 15. Harburn KL, Spaulding SJ. Muscle activity in the spinal cordinjured during wheelchair ambulation. Am J Occup Ther 1986;40: 629-36. 16. Scott JA, Donovan WH. The prevention of shoulder pain and contracture in the acute quadriplegia patient. Paraplegia 198 1; 19: 313-9. 17. Barber DB, Gail NG. Osteonecrosis: an overuse injury of the shoulder in paraplegia: a case report. Paraplegia 1991;29:423-6. 18. Powers MC, Newsam CJ, Gronley JK, Fontaine CA, Perry .I. Isometric shoulder torque in subjects with spinal cord injury. Arch Phys Med Rehabil 1994;75:761-5.
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