- Email: [email protected]
Carpal tunnel syndrome: Case study of an intercollegiate athlete
Industrial Ergonomics ELSEVIER
International Journal of Industrial Ergonomics 15 (1995) 297-300
i
Short communication
Carpal tunnel syndrome: Case study of an intercollegiate athlete Brian Kelly, Jennifer Jackson, Robert Yearout, Jeff Taylor Department of Management, Universityof North Carolina at Asheville (UNCA), One University Heights, Ashecille, NC 28804-3299, USA
Received May 28, 1994; accepted in revised form July 19, 1994
Abstract Carpal Tunnel Syndrome (CTS) is an increasingly common nerve entrapment disorder which is a direct result of humans subjecting their hands to hours of repetitive motion. This case's subject was a 21-year-old female intercollegiate volleyball setter diagnosed with CTS. The study's purpose was to monitor the progression of her symptoms' severity over the observation period and to demonstrate that surgery may not always be the answer. Analysis revealed that only task abstention and not conservative medical treatments is effective in symptom retardation.
Relevance to industry Industrial specialization and the use of personal computers has resulted in an exponential increase in the diagnosis CTS. Due to the concern of controlling worker's compensation cost, emphasis by ergonomists, industrial engineers and managers has concentrated on the work place. However, many CTS cases are not occupationally related. This case examines an exceptionally motivated student athlete. Industrial application drawn from this study is that motivated workers can and sometimes will perform with CTS. Ergonomists and industrial managers should not allow motivated employees to abuse themselves but take every opportunity to implement better ergonomically designed tasks and work stations. Keywords." Repetitive motion; Carpal tunnel syndrome; Nerve entrapment disorder; Carpal tunnel release surgery; Task frequency; Task duration; Intercollegiate athlete
1. Background T o d a y ' s t e c h n o l o g i c a l w o r k e n v i r o n m e n t has r e s u l t e d in an e x p o n e n t i a l i n c r e a s e in t h e d i a g n o sis of a r e p e t i t i v e m o t i o n e n t r a p m e n t d i s o r d e r l a b e l e d C a r p a l T u n n e l S y n d r o m e (CTS). G r e e r et al. (1992) r e p o r t e d t h a t C T S - r e l a t e d injuries have risen from 20,000 (1983) to a l m o s t 74,000 (1987) a n d e s t i m a t e d t h a t such injuries could c o m p r i s e
50% of w o r k e r s ' s c o m p e n s a t i o n claims by the y e a r 2000. D u e to c o n t r o l l i n g w o r k e r ' s c o m p e n s a tion cost concerns, e r g o n o m i s t s , e n g i n e e r s a n d m a n a g e r s have c o n c e n t r a t e d on the w o r k place. R o u t i n e i n d u s t r i a l r e p e t i t i v e a n d office v i d e o disp l a y unit tasks a r e c u r r e n t r e s e a r c h ' s focus. W i t h r e g a r d to athletics, t h e r e is very little i n f o r m a t i o n specifically a d d r e s s i n g CTS. Since this d e b i l i t a t ing c o n d i t i o n can occur any time h u m a n s subject
0169-8141/95/$09.50 © 1995 Elsevier Science B.V. All rights reserved SSDI 0169-8141(94)00067-0
298
B. Kelly et al. / International Journal of Industrial Ergonomics 15 (1995) 297-300
their hands to extensive hours of repetitive movement (Storti, 1990), highly specialized athletes maybe at risk. CTS occurs when there is compression of the median nerve within the carpal tunnel. The carpal tunnel, a confined space in the wrist, is made up of 8 carpal bones, 9 tendons, and ligaments. It is through this space that the median nerve passes before it branches into the hand. The ligaments and coverings (synovium), of the tendons in the carpal tunnel swell as a result of repetitive motion, causing tenosynovitis. Symptoms are quite painful, with the most common being paresthesia (numbness) throughout the sensory distribution of the median nerve in the hand. The victim may also experience burning pain in the index, middle, medial half of the ring finger, and weakness in the thumb, which are innervated by the median nerve. Symptoms may be felt spontaneously rather than constantly, with the majority of attacks being experienced at night (Storti, 1990). Smaller wrist dimensions, increased retention of body fluid, menstrual cycle, pregnancy, or breast feeding may
contribute to females' susceptibility in acquiring CTS (Konz and Mital, 1990). If left untreated, CTS can result in partial or complete disability of the hand. Konz and Mital (1990) suggested guidelines for preventing and alleviating the symptoms associated with CTS. Four broad categories were listed as follows; Frequency (reduce the number of cycles for a specific wrist), Joint Angle (keep the wrist in the neutral position), Force (reduce the amount of force and its duration) and Non-Ergonomic (medical). Medical approaches vary from the conservative (diuretics) to radical surgery. Extreme cases of CTS may require surgery. The procedure is known as Carpal Tunnel Release and ranks among the highest of successful surgeries. The tissue or tissues which cause the compression upon the median nerve is surgically extracted, thus relieving the compression. If surgery is elected and the patient returns to the unaltered repetitive task, CTS symptoms will resurface. Whether it be in the work place or a vocational activity, the best solution is to adopt preventative
A
Fig. 1. The setting task.
B. Kelly et al. / International Journal of Industrial Ergonomics 15 (199.5) 297-300
measures such as those previously suggested by Konz and Mital (1990).
2. Subject The volunteer subject was a 21-year-old female intercollegiate volleyball player. Until diagnosed (spring, 1992), her wrist pain was initially dismissed as arthritis. While attending the UNCA, the subject's symptoms became so severe after competition that she could not hold a cup of water with both hands. Symptoms progressed throughout the season as follows; shaking of the hands, tingling in the index and middle fingers, radiating hand pain, numbness and in worse case scenarios, tetany. Tetany, the uncontrollable locking of a muscle group, had begun to occur randomly in both hands. Upon formal diagnosis, her physician and the authors advised the subject to either alter her technique, cease competition or have surgery and then cease competition.
3. Task (setting the bali) In layman's terms, a volleyball setter is analogous to the importance of a football quarterback, she runs the show. Three hits are allowed on each side of the net, with every second hit being the setter's responsibility. Six participants are on the court at any time during a match. To become a nationally ranked volleyball setter (such as this subject), consistency was essential, thus requiring the exact same wrist motion each time the ball was set. It was this repetitive motion which caused the pain and numbness characteristic of CTS. Fig. 1 (Rhodarmer, 1994) illustrates the setting task. The subject's hands are in the receiving position (A). Elbows are slightly bent with the hands in the neutral position. The force of the ball causes hyperextension of the wrists and increased flexion of the elbows (B). It is at this point that maximum force is applied to the wrist. The initial stage of the follow-through (C) releases the ball. Wrists are returned to the neutral position and elbows are slightly bent. To complete the follow-through (D), the elbows are fully
299
extended with wrists remaining in neutral position. The subject's technique required the thumb, index and middle finger (digits principally affected by CTS) to make ball contact. The extreme hyperextension due to the force of the ball on the fingers is the principal cause of this condition's severity. The first three years of the subject's career resulted in 3941 assists. Since assists are only recorded when the team scores a point, only an estimated 33% of the subject's sets were recorded. An approximate number of times the subject set the ball prior to the study, excluding practice and warm-ups, was 11,823.
4. Method Criteria for evaluation included a multi-item semantic differential scale (symptoms), strength tests (kg/cm2), and measure performance (assists). Right and left hand grip strength was measured prior to and after each practice or game. Throughout the study the subject was treated with 2000 mg Ibuprofen and wrists constraints at night.
5. Results For the 1993 season (92 days) the subject recorded 1246 assists, which gave a total of 5287 career (four years) assists. Total sets were estimated to be over 15,860. Hand grip strength averaged 2.18 k g / c m 2 (right) and 1.74 k g / c m 2 (left) for the prior and 1.51 k g / c m 2 (right) and 1.21 k g / c m 2 (left) for the post game or practice conditions. Assists per game ranged from 19 to 152 with a single game average of 78.9 (SD 29.6). The R 2 technique (alpha = 0.05) was used to identify significant variables. Days (duration), grip strength and symptoms progression were the only significant variables. Fig. 2 illustrates grip strength deterioration. Linear regression was used to determine significant relationships. Only duration to grip strength was found to be significant (alpha =0.01). Multiple correlation coefficients and standard errors of the estimate were 0.47 and 0.45, and 0.38 and 0.37 for the right hand and left
300
B. Kelly et al. / International Journal of lndustrial Ergonomics 15 (1995) 297-300
3
o~
" "~g;
"2-
i 1" ~ 0.5-
i~ ,o
[ -
classic Hawthorne and the Western Electric Company study. Task performance frequency (duration), not sets per game, was the contributing variable in grip strength deterioration. Since setting consistency is critical to a team's competitive success, radical task alteration is infeasible.
2o oo
L.AND
........ L
30 4o so so 70 T,o. C REooENc ,N DA S ED,C
.AND
--.
80
~r 7. Conclusion 90
RED.OT ]
Fig. 2. Grip strength deterioration. hand models respectively. Symptom data was so widely dispersed that duration only explained less than 2% variation. Since data was determined to be heterogeneous, Satterthwaite's Approximation (alpha = 0.001) (Milliken and Johnson, 1984) was used to group comparisons. Prior game or practice grip strength was significantly higher in the right versus the left hand. Post condition of the right hand was significantly lower than the prior right hand strength. Post left hand strength was significantly lower than all other conditions. Thirty days after completing competition, the subject's grip strength and symptoms had returned to their original measured levels.
6. D i s c u s s i o n
Without previous years' data or additional subjects, treatment inferences cannot be drawn. The slight decrease in assists may be attributed to the graduation of two exceptional team-mates and not to performance. Even with severe pain and numbness, a courageous and dedicated human can endure and achieve continuous exceptional performance. This confirms the findings of the
Ceasing to perform a repetitive task that requires a prescribed technique, whether or not surgery is performed, appears to be the only way to achieve symptom relief. It can be stated that exceptionally talented female volleyball setters are at CTS risk. It is highly recommended that the setting duration (frequency) be reduced by recruiting more than one setter per squad. A prudent coach should retain at least three setters out of the 12 permissible squad members. An industrial application that can be drawn from this study is that motivated workers can and sometimes will perform with CTS. Industry should not allow employees to keep abusing themselves but take every opportunity to implement better ergonomically designed tasks and work stations. Innovative techniques such as frequent rotation within work cells may be appropriate.
References
Greet, B., Jenkins, W., Roberts, R., 1992. Carpal tunnel syndrome: A challenge for rehabilitation. Journal of Rehabilitation, 58: 43-46. Konz, S. and Mital, A., 1990. Guidelines: Carpal Tunnel Syndrome. International Journal of Industrial Ergonomics, 5: 175-180. Milliken, G. and Johnson, D., 1984, Analysis of Messy Data, Volume I: Designed Experiments. Lifetime Learning Publications, London. Storti, Peter A., 1990. Getting a grasp on carpal tunnel syndrome. Risk Management, 37: 40-48. Rhodarmer, Melanie A., 1994. Figure 1 illustration. UNCA, Asheville, NC.
International Journal of Industrial Ergonomics 15 (1995) 297-300
i
Short communication
Carpal tunnel syndrome: Case study of an intercollegiate athlete Brian Kelly, Jennifer Jackson, Robert Yearout, Jeff Taylor Department of Management, Universityof North Carolina at Asheville (UNCA), One University Heights, Ashecille, NC 28804-3299, USA
Received May 28, 1994; accepted in revised form July 19, 1994
Abstract Carpal Tunnel Syndrome (CTS) is an increasingly common nerve entrapment disorder which is a direct result of humans subjecting their hands to hours of repetitive motion. This case's subject was a 21-year-old female intercollegiate volleyball setter diagnosed with CTS. The study's purpose was to monitor the progression of her symptoms' severity over the observation period and to demonstrate that surgery may not always be the answer. Analysis revealed that only task abstention and not conservative medical treatments is effective in symptom retardation.
Relevance to industry Industrial specialization and the use of personal computers has resulted in an exponential increase in the diagnosis CTS. Due to the concern of controlling worker's compensation cost, emphasis by ergonomists, industrial engineers and managers has concentrated on the work place. However, many CTS cases are not occupationally related. This case examines an exceptionally motivated student athlete. Industrial application drawn from this study is that motivated workers can and sometimes will perform with CTS. Ergonomists and industrial managers should not allow motivated employees to abuse themselves but take every opportunity to implement better ergonomically designed tasks and work stations. Keywords." Repetitive motion; Carpal tunnel syndrome; Nerve entrapment disorder; Carpal tunnel release surgery; Task frequency; Task duration; Intercollegiate athlete
1. Background T o d a y ' s t e c h n o l o g i c a l w o r k e n v i r o n m e n t has r e s u l t e d in an e x p o n e n t i a l i n c r e a s e in t h e d i a g n o sis of a r e p e t i t i v e m o t i o n e n t r a p m e n t d i s o r d e r l a b e l e d C a r p a l T u n n e l S y n d r o m e (CTS). G r e e r et al. (1992) r e p o r t e d t h a t C T S - r e l a t e d injuries have risen from 20,000 (1983) to a l m o s t 74,000 (1987) a n d e s t i m a t e d t h a t such injuries could c o m p r i s e
50% of w o r k e r s ' s c o m p e n s a t i o n claims by the y e a r 2000. D u e to c o n t r o l l i n g w o r k e r ' s c o m p e n s a tion cost concerns, e r g o n o m i s t s , e n g i n e e r s a n d m a n a g e r s have c o n c e n t r a t e d on the w o r k place. R o u t i n e i n d u s t r i a l r e p e t i t i v e a n d office v i d e o disp l a y unit tasks a r e c u r r e n t r e s e a r c h ' s focus. W i t h r e g a r d to athletics, t h e r e is very little i n f o r m a t i o n specifically a d d r e s s i n g CTS. Since this d e b i l i t a t ing c o n d i t i o n can occur any time h u m a n s subject
0169-8141/95/$09.50 © 1995 Elsevier Science B.V. All rights reserved SSDI 0169-8141(94)00067-0
298
B. Kelly et al. / International Journal of Industrial Ergonomics 15 (1995) 297-300
their hands to extensive hours of repetitive movement (Storti, 1990), highly specialized athletes maybe at risk. CTS occurs when there is compression of the median nerve within the carpal tunnel. The carpal tunnel, a confined space in the wrist, is made up of 8 carpal bones, 9 tendons, and ligaments. It is through this space that the median nerve passes before it branches into the hand. The ligaments and coverings (synovium), of the tendons in the carpal tunnel swell as a result of repetitive motion, causing tenosynovitis. Symptoms are quite painful, with the most common being paresthesia (numbness) throughout the sensory distribution of the median nerve in the hand. The victim may also experience burning pain in the index, middle, medial half of the ring finger, and weakness in the thumb, which are innervated by the median nerve. Symptoms may be felt spontaneously rather than constantly, with the majority of attacks being experienced at night (Storti, 1990). Smaller wrist dimensions, increased retention of body fluid, menstrual cycle, pregnancy, or breast feeding may
contribute to females' susceptibility in acquiring CTS (Konz and Mital, 1990). If left untreated, CTS can result in partial or complete disability of the hand. Konz and Mital (1990) suggested guidelines for preventing and alleviating the symptoms associated with CTS. Four broad categories were listed as follows; Frequency (reduce the number of cycles for a specific wrist), Joint Angle (keep the wrist in the neutral position), Force (reduce the amount of force and its duration) and Non-Ergonomic (medical). Medical approaches vary from the conservative (diuretics) to radical surgery. Extreme cases of CTS may require surgery. The procedure is known as Carpal Tunnel Release and ranks among the highest of successful surgeries. The tissue or tissues which cause the compression upon the median nerve is surgically extracted, thus relieving the compression. If surgery is elected and the patient returns to the unaltered repetitive task, CTS symptoms will resurface. Whether it be in the work place or a vocational activity, the best solution is to adopt preventative
A
Fig. 1. The setting task.
B. Kelly et al. / International Journal of Industrial Ergonomics 15 (199.5) 297-300
measures such as those previously suggested by Konz and Mital (1990).
2. Subject The volunteer subject was a 21-year-old female intercollegiate volleyball player. Until diagnosed (spring, 1992), her wrist pain was initially dismissed as arthritis. While attending the UNCA, the subject's symptoms became so severe after competition that she could not hold a cup of water with both hands. Symptoms progressed throughout the season as follows; shaking of the hands, tingling in the index and middle fingers, radiating hand pain, numbness and in worse case scenarios, tetany. Tetany, the uncontrollable locking of a muscle group, had begun to occur randomly in both hands. Upon formal diagnosis, her physician and the authors advised the subject to either alter her technique, cease competition or have surgery and then cease competition.
3. Task (setting the bali) In layman's terms, a volleyball setter is analogous to the importance of a football quarterback, she runs the show. Three hits are allowed on each side of the net, with every second hit being the setter's responsibility. Six participants are on the court at any time during a match. To become a nationally ranked volleyball setter (such as this subject), consistency was essential, thus requiring the exact same wrist motion each time the ball was set. It was this repetitive motion which caused the pain and numbness characteristic of CTS. Fig. 1 (Rhodarmer, 1994) illustrates the setting task. The subject's hands are in the receiving position (A). Elbows are slightly bent with the hands in the neutral position. The force of the ball causes hyperextension of the wrists and increased flexion of the elbows (B). It is at this point that maximum force is applied to the wrist. The initial stage of the follow-through (C) releases the ball. Wrists are returned to the neutral position and elbows are slightly bent. To complete the follow-through (D), the elbows are fully
299
extended with wrists remaining in neutral position. The subject's technique required the thumb, index and middle finger (digits principally affected by CTS) to make ball contact. The extreme hyperextension due to the force of the ball on the fingers is the principal cause of this condition's severity. The first three years of the subject's career resulted in 3941 assists. Since assists are only recorded when the team scores a point, only an estimated 33% of the subject's sets were recorded. An approximate number of times the subject set the ball prior to the study, excluding practice and warm-ups, was 11,823.
4. Method Criteria for evaluation included a multi-item semantic differential scale (symptoms), strength tests (kg/cm2), and measure performance (assists). Right and left hand grip strength was measured prior to and after each practice or game. Throughout the study the subject was treated with 2000 mg Ibuprofen and wrists constraints at night.
5. Results For the 1993 season (92 days) the subject recorded 1246 assists, which gave a total of 5287 career (four years) assists. Total sets were estimated to be over 15,860. Hand grip strength averaged 2.18 k g / c m 2 (right) and 1.74 k g / c m 2 (left) for the prior and 1.51 k g / c m 2 (right) and 1.21 k g / c m 2 (left) for the post game or practice conditions. Assists per game ranged from 19 to 152 with a single game average of 78.9 (SD 29.6). The R 2 technique (alpha = 0.05) was used to identify significant variables. Days (duration), grip strength and symptoms progression were the only significant variables. Fig. 2 illustrates grip strength deterioration. Linear regression was used to determine significant relationships. Only duration to grip strength was found to be significant (alpha =0.01). Multiple correlation coefficients and standard errors of the estimate were 0.47 and 0.45, and 0.38 and 0.37 for the right hand and left
300
B. Kelly et al. / International Journal of lndustrial Ergonomics 15 (1995) 297-300
3
o~
" "~g;
"2-
i 1" ~ 0.5-
i~ ,o
[ -
classic Hawthorne and the Western Electric Company study. Task performance frequency (duration), not sets per game, was the contributing variable in grip strength deterioration. Since setting consistency is critical to a team's competitive success, radical task alteration is infeasible.
2o oo
L.AND
........ L
30 4o so so 70 T,o. C REooENc ,N DA S ED,C
.AND
--.
80
~r 7. Conclusion 90
RED.OT ]
Fig. 2. Grip strength deterioration. hand models respectively. Symptom data was so widely dispersed that duration only explained less than 2% variation. Since data was determined to be heterogeneous, Satterthwaite's Approximation (alpha = 0.001) (Milliken and Johnson, 1984) was used to group comparisons. Prior game or practice grip strength was significantly higher in the right versus the left hand. Post condition of the right hand was significantly lower than the prior right hand strength. Post left hand strength was significantly lower than all other conditions. Thirty days after completing competition, the subject's grip strength and symptoms had returned to their original measured levels.
6. D i s c u s s i o n
Without previous years' data or additional subjects, treatment inferences cannot be drawn. The slight decrease in assists may be attributed to the graduation of two exceptional team-mates and not to performance. Even with severe pain and numbness, a courageous and dedicated human can endure and achieve continuous exceptional performance. This confirms the findings of the
Ceasing to perform a repetitive task that requires a prescribed technique, whether or not surgery is performed, appears to be the only way to achieve symptom relief. It can be stated that exceptionally talented female volleyball setters are at CTS risk. It is highly recommended that the setting duration (frequency) be reduced by recruiting more than one setter per squad. A prudent coach should retain at least three setters out of the 12 permissible squad members. An industrial application that can be drawn from this study is that motivated workers can and sometimes will perform with CTS. Industry should not allow employees to keep abusing themselves but take every opportunity to implement better ergonomically designed tasks and work stations. Innovative techniques such as frequent rotation within work cells may be appropriate.
References
Greet, B., Jenkins, W., Roberts, R., 1992. Carpal tunnel syndrome: A challenge for rehabilitation. Journal of Rehabilitation, 58: 43-46. Konz, S. and Mital, A., 1990. Guidelines: Carpal Tunnel Syndrome. International Journal of Industrial Ergonomics, 5: 175-180. Milliken, G. and Johnson, D., 1984, Analysis of Messy Data, Volume I: Designed Experiments. Lifetime Learning Publications, London. Storti, Peter A., 1990. Getting a grasp on carpal tunnel syndrome. Risk Management, 37: 40-48. Rhodarmer, Melanie A., 1994. Figure 1 illustration. UNCA, Asheville, NC.