- Email: [email protected]
Reproducibilty of partial weight bearing
Injury, Int. J. Care Injured (2005) 36, 556—559
www.elsevier.com/locate/injury
Reproducibilty of partial weight bearing A. Malviyaa,*, J. Richardsb, Richard K. Jonesb, A. Udwadiac, J. Doylec a
Fairfield Hospital, Bury, 75 Stockdale Place, Edgbaston, Birmingham B15 3XH, UK Centre for Rehabilitation and Human Performance Research, University of Salford, Salford, UK c Fairfield Hospital, Bury, UK b
Accepted 4 October 2004
KEYWORDS Partial; Weight bearing; Reproducibility; Retention
Summary Objectives: To find out whether partial weight bearing can be reproduced and retained. Design: In vivo experiment in normal subjects. Intervention: Training for partial weight bearing (25% of body weight) using bathroom scales. Main outcome measurement: Reproducibility on force platform immediately after training and after 60 min. Results: Twelve subjects were asked to reproduce 25% of their body weight through either the dominant or non-dominant limb on force platform after three practice attempts on bathroom scales with concurrent visual feedback. No feedback was provided after the measurements on force plate. The process was repeated after 1 h without any practice sessions in the interim period to find out if the weight practised could be retained. The mean 0-min reading was found to be 25.9% of body weight while the mean 60-min reading was found to be 24.4%. The p-value for the difference between the two means was found to be 0.3841. Conclusions: This study indicates that partial weight bearing instructions can be quantified and graded. Simple bathroom scales are sufficient to educate the patients and this can be practised at home after an initial period of supervision. # 2004 Elsevier Ltd. All rights reserved.
Introduction Grading the weight bearing status forms an integral part of further management of orthopaedic patients. It remains a dilemma because the pursuit * Corresponding author. Tel.: +44 121 2423624. E-mail address: [email protected] (A. Malviya).
to find the correct weight and the way to find a simple solution to the problem remains elusive. Moreover, a lot depends on the compliance as it is very easy for patients to either apply too little when in pain or too much when having good relief, which may be related to a high dose of analgesia or a successful but potentially fragile operative procedure.
0020–1383/$ — see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2004.10.004
Partial weight bearing
Although studies have been carried out to find out whether weight bearing can be taught, the available literature is quite limited. The methods used to educate and assess this skill have included force platform,2 bathroom scales,2 insole pressure measuring devices,4,5 limb load monitors,1 etc. with various kinds of feedback. It was found that such training was of limited value since subjects during and after training often exceeded target loads by as much as 50% or more.6 Retained learning was found to diminish rapidly. There has been a uniform disappointment in the result. Force monitoring platforms have been proposed as a useful tool for training and rehabilitation of patients requiring crutches or walker for protective weight bearing.7 Until now there has been no cost effective and readily available way of ascertaining the accuracy of patient performance. We decided to study whether a fixed amount of weight bearing can be ‘‘taught’’ to normal subjects with a simple device (bathroom scales) and whether it can be reproduced and retained for a longer duration. The aim was to find out whether the subjects were able to reproduce the taught weight on the force platform without any visual feedback and to check whether the subjects were able to remember the same weight after 1 h despite having not practiced in the interim period.
557
A paired t-test was performed to compare the difference between the means of the 0- and 60-min readings. Spearman’s r was used to correlate the two readings.
Results Table 1 shows the mean and standard deviation percentage of body weight (%BW) for the 12 subjects included in the study at 0 and 60 min. Both the dominant and non-dominant sides were grouped together. No significant difference was observed between the two tests at 0 and 60 min with the dominant and non-dominant sides grouped. When the data were separated into dominant and no dominant sides (Table 2) no significant difference was found for either limb, however, the dominant limb showed the more consistent and reproducible load. All the study subjects behaved in the same manner and all the values were within two standard deviation of the mean and thus within 95% confidence limits. Non-parametric correlation (Spearman’s r) shows a significant relationship, moderate in magnitude between the pressure studies at 0 and 60 min (r = 0.657, p = 0.02)
Discussion Materials and methods Twelve normal subjects (six males and six females) with an age range 28—42 were selected at random. Each subject was asked to reproduce about 25% of body weight on bathroom scales through either the dominant or non-dominant limb with concurrent visual feedback. The dominant limb was defined as the side with which the subject would kick a ball. All subjects were right leg dominant. Three practice attempts with one leg on the bathroom scale and another on a platform adjusted to the same level was allowed. Immediately after these practice attempts they were asked to reproduce a similar weight through the ‘‘study leg’’ on a force platform (Kistler, Switzerland) for 15 s sampling at 100 Hz. Five readings were taken so as to exclude any occurrence by chance. No feedback was provided as to the accuracy of the weight bearing. After 1 h the readings were repeated but this time without any practice attempts. The mean reading for each session was calculated using the middle 5 s period for each of the five attempts. This was done to exclude the erroneous readings when the subject was getting accustomed to the force platform.
The findings in our study were quite encouraging especially for the dominant leg. None of the subjects could perfectly reproduce the weight on the force platform but most of them were close to the target load. It was found that immediately after the practice sessions, which included only three attempts at the bathroom scales, the reproducibility was up to 25.9% of the body weight. After a period of 1 h without any practice in between the mean reading was 24.4% of body weight. There was a loss of reproducibility of about 1.5% body weight, however both were very close to the 25% body weight target. When the data were classified into dominant and non-dominant sides, it was found that the standard deviation of the dominant side was less than that of the non-dominant side (Table 2). This shows that the variability between the 0 and 60 min readings was Table 1 Subject (n = 12)
0 min (% body weight)
60 min (% body weight)
Mean S.D. p-value
25.9 7.7
24.4 9.9 0.3841
558
A. Malviya et al.
Table 2 Subject (n = 12)
Dominant (% body weight) (n = 6) 0 min
60 min
0 min
60 min
Mean S.D. p-value
29.1 4.4 0.9783
29.1 3.1
22.6 9.3 0.3091
19.8 12.4
much less in case of the dominant side and might be related to the higher proprioceptive input from the dominant side resulting in better retention. Moreover, the means of the 0- and 60-min readings were more consistent on the dominant side. From the statistical analysis, which compared the difference between the means of the 0 and 60 min, no significant difference (p > 0.05) was found between the two readings showing that the delay of 1 h between attempts did not have any effect on the load reproduced. This is true both for the data grouped together and separated into dominant and non-dominant sides. Previous studies had shown that a force platform is a better device to give accurate partial weight bearing instructions.2 The fact that bathroom scales are sufficient for this purpose means that a force platform need not be put into every physiotherapy department. It would also mean that if appropriate the clinical staff could let the patients know exactly how much weight they can actually put through the affected limb rather than being vague about it which they can practice at home. However, it would be ideal for an initial period to be spent educating this skill in the physiotherapy department preferably with post-response feedback for better retention than concurrent feedback, which has been found to be shortlasting.7 It had been thought in the past that the effect of training was of limited value since subjects, during training and after, often exceeded target loads.6 Any retained learning was found to diminish rapidly on the first and second days after training.6 Our study shows that target loads can be reproduced and remembered at least till 1 h, but a similar study design needs to be carried out with a longer duration in both the normal population and the patient population. The fact that bathroom scales are sufficient to teach this skill means that regular practice at home can help in better and longer retention. The accuracy of partial weight bearing has been in question.3 It is believed the training should be such that the biomechanics are not altered when weight is being put through the bathroom scales. In our study we were careful that both the legs were at the same level when the partial weight bearing was
Non-dominant (% body weight) (n = 6)
being practised. We used a platform to raise the other foot to the same level as that of the bathroom scale for this purpose. This simple manoeuvre may have contributed to good preliminary results. The fact that the results were better for the dominant side can be related to the higher proprioceptive input through the dominant leg. It would indicate that similar results could probably be reproduced on the non-dominant limb with more training. Instructions for partial weight bearing form an integral part of management of many orthopaedic patients and there would be very few clinicians who have not given these instructions in day-to-day orthopaedic practice. The implications of this study thus encompass a wide range of patients. Instead of an unscientific approach towards partial weight bearing a more scientific and practical protocol can be adopted. The instructions can be graded starting from 25% of body weight and thereby increasing in units of 25% to an ultimate full weight bearing status depending on the satisfactory progression of the patient’s condition.
Conclusion The demand of the present time is to formulate a strategy in which clinical staff can teach various grades of weight bearing in terms the patient can understand and reproduce. Rather than just progressing from a stage of an imaginary partial weight bearing status of which staff and the patients understand very little to one of full weight bearing, it is needed to set a protocol for further management of patients with such a requirement. The study aimed to provide a means of achieving this with the help of simple bathroom scales and indicates that such instructions can be given and followed with the help of a device available in almost all households with adequate training.
References 1. Gapsis JJ, Grabois M, Borrell RM, et al. Limb load monitor: evaluation of a sensory feedback device for controlled weight bearing. Arch Phys Med Rehabil 1982;63(1):38—41.
Partial weight bearing
2. Gray FB, Gray C, McClanahan JW. Assessing the accuracy of partial weight-bearing instruction. Am J Orthop 1998;27 (8):558—60. 3. Gupta SK, Dabke HV, Holt CA, et al. How accurate is partial weight bearing? Injury 2003;34:602—3 (Abstracts). 4. Perren T, Matter P. Feedback controlled weight bearing following osteosynthesis of the lower extremity. Swiss Surg 1996;2(6):252—8. 5. Tveit M, Karrholm J. Low effectiveness of prescribed partial weight bearing. Continuous recording of vertical loads
559
using a new pressure-sensitive insole. J Rehabil Med 2001;33(1):42—6. 6. Warren CG, Lehmann JF. Training procedures and biofeedback methods to achieve controlled partial weight bearing: an assessment. Arch Phys Med Rehabil 1975;56(10):449—55. 7. Winstein CJ, Pohl PS, Cardinale. et al. Learning a partialweight-bearing skill: effectiveness of two forms of feedback. Phys Ther 1996;76(9):985—93.
www.elsevier.com/locate/injury
Reproducibilty of partial weight bearing A. Malviyaa,*, J. Richardsb, Richard K. Jonesb, A. Udwadiac, J. Doylec a
Fairfield Hospital, Bury, 75 Stockdale Place, Edgbaston, Birmingham B15 3XH, UK Centre for Rehabilitation and Human Performance Research, University of Salford, Salford, UK c Fairfield Hospital, Bury, UK b
Accepted 4 October 2004
KEYWORDS Partial; Weight bearing; Reproducibility; Retention
Summary Objectives: To find out whether partial weight bearing can be reproduced and retained. Design: In vivo experiment in normal subjects. Intervention: Training for partial weight bearing (25% of body weight) using bathroom scales. Main outcome measurement: Reproducibility on force platform immediately after training and after 60 min. Results: Twelve subjects were asked to reproduce 25% of their body weight through either the dominant or non-dominant limb on force platform after three practice attempts on bathroom scales with concurrent visual feedback. No feedback was provided after the measurements on force plate. The process was repeated after 1 h without any practice sessions in the interim period to find out if the weight practised could be retained. The mean 0-min reading was found to be 25.9% of body weight while the mean 60-min reading was found to be 24.4%. The p-value for the difference between the two means was found to be 0.3841. Conclusions: This study indicates that partial weight bearing instructions can be quantified and graded. Simple bathroom scales are sufficient to educate the patients and this can be practised at home after an initial period of supervision. # 2004 Elsevier Ltd. All rights reserved.
Introduction Grading the weight bearing status forms an integral part of further management of orthopaedic patients. It remains a dilemma because the pursuit * Corresponding author. Tel.: +44 121 2423624. E-mail address: [email protected] (A. Malviya).
to find the correct weight and the way to find a simple solution to the problem remains elusive. Moreover, a lot depends on the compliance as it is very easy for patients to either apply too little when in pain or too much when having good relief, which may be related to a high dose of analgesia or a successful but potentially fragile operative procedure.
0020–1383/$ — see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2004.10.004
Partial weight bearing
Although studies have been carried out to find out whether weight bearing can be taught, the available literature is quite limited. The methods used to educate and assess this skill have included force platform,2 bathroom scales,2 insole pressure measuring devices,4,5 limb load monitors,1 etc. with various kinds of feedback. It was found that such training was of limited value since subjects during and after training often exceeded target loads by as much as 50% or more.6 Retained learning was found to diminish rapidly. There has been a uniform disappointment in the result. Force monitoring platforms have been proposed as a useful tool for training and rehabilitation of patients requiring crutches or walker for protective weight bearing.7 Until now there has been no cost effective and readily available way of ascertaining the accuracy of patient performance. We decided to study whether a fixed amount of weight bearing can be ‘‘taught’’ to normal subjects with a simple device (bathroom scales) and whether it can be reproduced and retained for a longer duration. The aim was to find out whether the subjects were able to reproduce the taught weight on the force platform without any visual feedback and to check whether the subjects were able to remember the same weight after 1 h despite having not practiced in the interim period.
557
A paired t-test was performed to compare the difference between the means of the 0- and 60-min readings. Spearman’s r was used to correlate the two readings.
Results Table 1 shows the mean and standard deviation percentage of body weight (%BW) for the 12 subjects included in the study at 0 and 60 min. Both the dominant and non-dominant sides were grouped together. No significant difference was observed between the two tests at 0 and 60 min with the dominant and non-dominant sides grouped. When the data were separated into dominant and no dominant sides (Table 2) no significant difference was found for either limb, however, the dominant limb showed the more consistent and reproducible load. All the study subjects behaved in the same manner and all the values were within two standard deviation of the mean and thus within 95% confidence limits. Non-parametric correlation (Spearman’s r) shows a significant relationship, moderate in magnitude between the pressure studies at 0 and 60 min (r = 0.657, p = 0.02)
Discussion Materials and methods Twelve normal subjects (six males and six females) with an age range 28—42 were selected at random. Each subject was asked to reproduce about 25% of body weight on bathroom scales through either the dominant or non-dominant limb with concurrent visual feedback. The dominant limb was defined as the side with which the subject would kick a ball. All subjects were right leg dominant. Three practice attempts with one leg on the bathroom scale and another on a platform adjusted to the same level was allowed. Immediately after these practice attempts they were asked to reproduce a similar weight through the ‘‘study leg’’ on a force platform (Kistler, Switzerland) for 15 s sampling at 100 Hz. Five readings were taken so as to exclude any occurrence by chance. No feedback was provided as to the accuracy of the weight bearing. After 1 h the readings were repeated but this time without any practice attempts. The mean reading for each session was calculated using the middle 5 s period for each of the five attempts. This was done to exclude the erroneous readings when the subject was getting accustomed to the force platform.
The findings in our study were quite encouraging especially for the dominant leg. None of the subjects could perfectly reproduce the weight on the force platform but most of them were close to the target load. It was found that immediately after the practice sessions, which included only three attempts at the bathroom scales, the reproducibility was up to 25.9% of the body weight. After a period of 1 h without any practice in between the mean reading was 24.4% of body weight. There was a loss of reproducibility of about 1.5% body weight, however both were very close to the 25% body weight target. When the data were classified into dominant and non-dominant sides, it was found that the standard deviation of the dominant side was less than that of the non-dominant side (Table 2). This shows that the variability between the 0 and 60 min readings was Table 1 Subject (n = 12)
0 min (% body weight)
60 min (% body weight)
Mean S.D. p-value
25.9 7.7
24.4 9.9 0.3841
558
A. Malviya et al.
Table 2 Subject (n = 12)
Dominant (% body weight) (n = 6) 0 min
60 min
0 min
60 min
Mean S.D. p-value
29.1 4.4 0.9783
29.1 3.1
22.6 9.3 0.3091
19.8 12.4
much less in case of the dominant side and might be related to the higher proprioceptive input from the dominant side resulting in better retention. Moreover, the means of the 0- and 60-min readings were more consistent on the dominant side. From the statistical analysis, which compared the difference between the means of the 0 and 60 min, no significant difference (p > 0.05) was found between the two readings showing that the delay of 1 h between attempts did not have any effect on the load reproduced. This is true both for the data grouped together and separated into dominant and non-dominant sides. Previous studies had shown that a force platform is a better device to give accurate partial weight bearing instructions.2 The fact that bathroom scales are sufficient for this purpose means that a force platform need not be put into every physiotherapy department. It would also mean that if appropriate the clinical staff could let the patients know exactly how much weight they can actually put through the affected limb rather than being vague about it which they can practice at home. However, it would be ideal for an initial period to be spent educating this skill in the physiotherapy department preferably with post-response feedback for better retention than concurrent feedback, which has been found to be shortlasting.7 It had been thought in the past that the effect of training was of limited value since subjects, during training and after, often exceeded target loads.6 Any retained learning was found to diminish rapidly on the first and second days after training.6 Our study shows that target loads can be reproduced and remembered at least till 1 h, but a similar study design needs to be carried out with a longer duration in both the normal population and the patient population. The fact that bathroom scales are sufficient to teach this skill means that regular practice at home can help in better and longer retention. The accuracy of partial weight bearing has been in question.3 It is believed the training should be such that the biomechanics are not altered when weight is being put through the bathroom scales. In our study we were careful that both the legs were at the same level when the partial weight bearing was
Non-dominant (% body weight) (n = 6)
being practised. We used a platform to raise the other foot to the same level as that of the bathroom scale for this purpose. This simple manoeuvre may have contributed to good preliminary results. The fact that the results were better for the dominant side can be related to the higher proprioceptive input through the dominant leg. It would indicate that similar results could probably be reproduced on the non-dominant limb with more training. Instructions for partial weight bearing form an integral part of management of many orthopaedic patients and there would be very few clinicians who have not given these instructions in day-to-day orthopaedic practice. The implications of this study thus encompass a wide range of patients. Instead of an unscientific approach towards partial weight bearing a more scientific and practical protocol can be adopted. The instructions can be graded starting from 25% of body weight and thereby increasing in units of 25% to an ultimate full weight bearing status depending on the satisfactory progression of the patient’s condition.
Conclusion The demand of the present time is to formulate a strategy in which clinical staff can teach various grades of weight bearing in terms the patient can understand and reproduce. Rather than just progressing from a stage of an imaginary partial weight bearing status of which staff and the patients understand very little to one of full weight bearing, it is needed to set a protocol for further management of patients with such a requirement. The study aimed to provide a means of achieving this with the help of simple bathroom scales and indicates that such instructions can be given and followed with the help of a device available in almost all households with adequate training.
References 1. Gapsis JJ, Grabois M, Borrell RM, et al. Limb load monitor: evaluation of a sensory feedback device for controlled weight bearing. Arch Phys Med Rehabil 1982;63(1):38—41.
Partial weight bearing
2. Gray FB, Gray C, McClanahan JW. Assessing the accuracy of partial weight-bearing instruction. Am J Orthop 1998;27 (8):558—60. 3. Gupta SK, Dabke HV, Holt CA, et al. How accurate is partial weight bearing? Injury 2003;34:602—3 (Abstracts). 4. Perren T, Matter P. Feedback controlled weight bearing following osteosynthesis of the lower extremity. Swiss Surg 1996;2(6):252—8. 5. Tveit M, Karrholm J. Low effectiveness of prescribed partial weight bearing. Continuous recording of vertical loads
559
using a new pressure-sensitive insole. J Rehabil Med 2001;33(1):42—6. 6. Warren CG, Lehmann JF. Training procedures and biofeedback methods to achieve controlled partial weight bearing: an assessment. Arch Phys Med Rehabil 1975;56(10):449—55. 7. Winstein CJ, Pohl PS, Cardinale. et al. Learning a partialweight-bearing skill: effectiveness of two forms of feedback. Phys Ther 1996;76(9):985—93.