Disability and Rehabilitation
ISSN: 0963-8288 (Print) 1464-5165 (Online) Journal homepage: http://www.tandfonline.com/loi/idre20
Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture Sara Mannberg Bäckman, Sara Stråt, Susanne Ahlström & Nina Brodin To cite this article: Sara Mannberg Bäckman, Sara Stråt, Susanne Ahlström & Nina Brodin (2015): Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture, Disability and Rehabilitation To link to this article: http://dx.doi.org/10.3109/09638288.2015.1044623
Published online: 11 May 2015.
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Date: 18 October 2015, At: 21:52
http://informahealthcare.com/dre ISSN 0963-8288 print/ISSN 1464-5165 online Disabil Rehabil, Early Online: 1–6 ! 2015 Informa UK Ltd. DOI: 10.3109/09638288.2015.1044623
RESEARCH PAPER
Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture Sara Mannberg Ba¨ckman1, Sara Stra˚t1, Susanne Ahlstro¨m1, and Nina Brodin1,2 Division of Physiotherapy, Orthopaedic Clinic, Danderyd Hospital, Stockholm, Sweden and 2Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm, Sweden
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Abstract
Keywords
Purpose: To describe content validity, concurrent validity, sensitivity to change, internal consistency and the outcome distribution of the Patient Specific Functional Scale (PSFS) in patients with proximal humeral fracture. Method: Fifty-three patients with proximal humeral fracture treated conservatively or surgically with plate and screw or intramedullary nail were recruited 6 weeks (±1 week) post-trauma or post-surgery. The following assessments were used: the PSFS, patient global score, shoulder function assessment, grip strength and Western Ontario Osteoarthritis of the shoulder Index (WOOS), before start of (n ¼ 53) and after (n ¼ 22) 2–3 months of group rehabilitation. Results: In total, 96% of the activities stated in the PSFS was classified in the International Classification of Functioning, Disability and Health activity component and 62% were found in the WOOS. Correlations between measures were low. The PSFS was highly sensitive to change to a period of group rehabilitation. All questions of the PSFS contributed to the total score. Both floor and ceiling effects could be noted. Conclusion: The PSFS shows satisfying measurement properties and may be a useful complement in the evaluation of individual changes during a period of rehabilitation after proximal humeral fracture.
ICF, measurement, patient preference, rehabilitation History Received 13 October 2014 Revised 16 April 2015 Accepted 21 April 2015 Published online 11 May 2015
ä Implications for Rehabilitation
The PSFS assesses on activity level in patients with proximal humeral fracture. The PSFS is sensitive to change for group rehabilitation after humeral fracture. The PSFS can be useful for goal-setting, motivating and individually tailoring rehabilitation activities. The PSFS should be used in addition to specific measures of body functions and general health.
Introduction Of all fractures treated in orthopedic clinics, approximately 4–5% are proximal humeral fractures [1–5]. Proximal humeral fracture is the third most common fracture among elderly people following proximal femur fracture and distal radius fracture [6]. Approximately 75% of all who incur a proximal humeral fracture are over 60 years of age, and the fracture type is three times more common among women than men [2,7,8]. Almost all proximal humeral fractures are minimally displaced and can therefore be treated conservatively with early movement training and usually with satisfying results [3,5,7–9]. Several studies show that more complex proximal humeral fractures with three or more parts in
Address for correspondence: Nina Brodin, Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institute, 23 100, S 141 83 Huddinge, Sweden. Tel: +46 8 524 88843. Fax: +46 8 524 88813. E-mail: [email protected]
healthy and active patients should be treated surgically to optimize shoulder function [7–9]. After a proximal humeral fracture, a concerted effort by the patient, surgeon and physical therapist is required for the patient to regain good functionality of the shoulder joint [8]. A dilemma in rehabilitation is that early and aggressive mobilization can lead to the fracture healing the wrong way or not healing at all, while a too long immobilization can lead to stiffness and contracture. Individually tailored and graded exercise until full functional mobility in the shoulder joint has been achieved is the foundation of successful rehabilitation after both conservatively and operatively treated proximal humeral fracture [8]. Six to eight weeks post-operatively or post-trauma, both operatively and conservatively treated patients perform active range of motion exercises and resistance training with light weights [8]. Individually tailored exercise based on activity limitations stated by the patient can improve adherence to rehabilitation. It also seems more meaningful to strive for and achieve personally
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set goals [10,11]. Pre-defined questionnaires and/or general scales might include several parts that do not provide answers to the patient’s specific problem. A patient-specific instrument, on the other hand, can record and evaluate changes on individual patient level. Selected activities are therefore relevant and meaningful to the patient [10,12–15]. The Patient-Specific Functional Scale (PSFS) was developed by physical therapists in Canada [14], and focuses on the patient’s own perceived activity limitations. The patient is asked about current functional status instead of being asked about changes in functionality, as in many other instruments [10,11,14]. The measurements properties of the Canadian version of the PSFS have been described in studies on patients with lower back pain, knee dysfunction, neck dysfunction, cervical radiculopathy and in patients with upper extremity musculoskeletal problems. In all these studies, the PSFS has proven valid and reliable [10,11,14– 16]. A Swedish translation of the instrument has been made by Broberg, Johansson and Roos, which was updated in 2005. The translation is distributed by the Swedish Association of Registered Physical therapists (LSR) (http://www.sjukgymnastforbundet.se/ lsr_old_asp/matmetoder/index.asp). The Swedish version of the PSFS has been tested in patients with surgically treated carpometacarpal joint osteoarthritis [17], showing very good content validity and good reliability. When assessing and evaluating rehabilitation in a clinical setting, a common framework such as the ‘‘International Classification of Functioning, Disability and Health’’ (ICF) can be useful. The ICF is a classification as well as a model, where the classification part consists of a number of different factors which in turn can be used in different approaches to describe an individual’s ability to function [18,19]. Using the ICF coding rules, information can be coded in various items, contributing to a more secure way to determine the level of which a method assesses [18]. In a study by Fairbairn et al. [20], all activities described in the PSFS were coded according to the ICF coding rules. Of all the activities that were coded, 80% could be categorized in the ICF component ‘‘Activities’’. In a similar study by Rosengren et al. [17], 100% of the activities were categorized in the ICF component ‘‘activities’’. There is currently no specific measure of activity limitation directed towards proximal humeral fractures, and no patientspecific functional assessment instrument has been tested on this group of patients according to validity and reliability requirements. The use of the PSFS can lead to greater understanding, refined planning and structure of the rehabilitation. If used in assessment of rehabilitation, it might increase the patient’s feeling of participation in the rehabilitation and motivate towards reaching personal goals. The PSFS is time-efficient and easy to manage. It is therefore interesting to test the PSFS in this particular group of patients to assess its usefulness for the individual, as well as for the evaluation of an entire period of rehabilitation. The purpose of this study was to describe content validity, concurrent validity, sensitivity to change, internal consistency and the outcome distribution of the PSFS in patients with proximal humeral fracture.
Methods Patients A total of 53 patients were included in the study, and the recruitment was based on convenience (Table 1). Assessments were performed in 3.5 years during 2008–2012. Inclusion criteria were: patients with proximal humeral fracture treated conservatively or surgically with plate and screw or intramedullary nail, 6 weeks (±1 week) post-trauma or post-operatively. Exclusion
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criteria were: (a) difficulties understanding and speaking Swedish, (b) cognitive limitations affecting the ability to follow instructions and to fill out questionnaires, (c) patients with proximal humeral fracture treated surgically with any type of shoulder prosthetic, cerclage or screw, (d) other acute or disabling injuries in the same arm. Demographic data collected from each patient were: sex, age, hand dominance, injured side, and amount and type of pain medication. Type of fracture and type of treatment were collected from the patient’s medical record (Table 1). Study protocol Patients were recruited at a physical therapist appointment during a scheduled visit at the orthopedic clinic 6 weeks (±1 week) posttrauma or post-operatively. Patients were asked to give a written consent after they had received oral and written information about the study and had agreed to participate. The five physical therapists that were collecting data had at least 3 years of experience working with this type of patients, and they were all co-trained, before the study started, in how all the assessments should be performed. A separate study protocol was kept for each patient, respectively. Assessments were performed in the following order: demographic data, the PSFS [10,11,16], patient global score (PGS) [21,22], shoulder function assessment [23–25], grip strength (Grippit) [24,26,27] and Western Ontario Osteoarthritis of the Shoulder Index (WOOS) [28,29]. Assessments took 15–25 min and were performed in connection to a regular visit at the physical therapist. The second assessment was performed after 2–4 months of shoulder rehabilitation (once a week). Dose and type of pain medication, the PSFS (rating of the same activities chosen at the first test session), PGS, shoulder function assessment, Grippit, WOOS and Global Rating of Change Scale (GRC) were then assessed. Assessments The following assessments were used. The PSFS is a patientspecific self-report instrument where the patient is asked to state three activities currently difficult or impossible to perform due to the injury, symptom or illness [10,11,16]. The difficulty of performing each activity is rated on an 11 point scale, 0–10, were 0 is ‘‘Unable to perform activity’’ and 10 is ‘‘Able to perform activity at same level as before injury or problem’’. The PSFS takes about four minutes to perform, and a change of two steps or more is considered to represent a clinically relevant change [14]. The patient global score (PGS) is a self-report instrument to evaluate general wellbeing. On a 100 mm Visual Analog Scale (VAS), were 0 is ‘‘worst wellbeing’’ and 100 is ‘‘best wellbeing’’, the patient is asked to rate their general wellbeing, considering the current injury [21,22]. The shoulder function assessment ad modum Bostro¨m is developed for use in rheumatic diseases, but is also frequently used within orthopedic rehabilitation. The assessment include five functional tasks; hand-to-ceiling, hand-to-opposite-shoulder, Table 1. Demographics of 53 participants with humeral fracture. Gender, male/female (n) Age, years, median (range) Injured dominant side (%) Conservative/surgical treatment (n) Collum chirurgicum fracture (n) Tuberculum majus fracture (n) Combinated collum chirurgicum/tuberculum majus fracture (n) Proximal humeral fracture (n) On current pain medication (%)
8/45 60 (34–77) 51 27/26 10 5 22 16 83
Validation of PSFS for humeral fracture
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hand-to-neck, hand-to-back and hand-to-sacrum. Each task is scored on a six-grade scale from 1 to 6 where 1 indicates a severe disability and 6 normal function. In the current study, the scale was reversed to better fit with the remaining assessments [23–25]. Grip strength (Grippit, AB Detektor, Go¨teborg, Sweden) is an electronic device assessing the maximal isometric grip strength in Newton (N). Patients were asked to sit in an upright position with their arm and hand in a standard position. Thereafter, the patients were asked to press together/grip around a handle, as hard as possible, during the 10 s test [24,26,27]. The Western Ontario Osteoarthritis of the Shoulder index (WOOS), is a diagnosis specific measurement for evaluating the quality of life in relation to shoulder function of symptomatic primary osteoarthritis of the shoulder. The WOOS consists of 19 statements, divided in to four categories: (a) physical symptoms, (b) sports/recreation/work, (c) lifestyle, (d) emotions. The patients answer each question by marking on a 100 mm visual analog scale (VAS). The WOOS ranges from 0 to 1900 where 0 represents no symptoms/best quality of life [28,29]. A Swedish version of the ¨ berg and WOOS translated by Hultenheim Klintberg [30], Lind, O Lillkrona is available from the Swedish Shoulder and Elbow Society (SSAS) [31]. The global rating of change scale (GRC) was used at the second assessment only. The GRC scale consists of two parts, where each part starts with a question regarding direction of change (better/worse/no change) and is then scored on a 15 point scale ranging from +7 (indicating improvement) to 7 (indicating impairment). The first part asks about the magnitude of change and the second part asks about the importance of change. Only the question regarding magnitude of the GRC was used in this study, and was answered by both the participants and their physical therapist, each unaware of the other persons answer [10,32].
regarding both direction (better/worse/no change) and level (±0–7). Internal consistency of the PSFS was estimated using the Spearman correlation between PSFS median and the three questions independently. This was done to assure that no question was abstracted from the other three, and that all questions contributed to the total sore. A Spearman correlation of approximately rs ¼ 0.70 was expected between all three questions, respectively. Outcome distribution regarding floor and/or ceiling effects of the PSFS was described by median along with interquartile range (Q1–Q3), and the percentage of participants’ ratings in the bottom or top of the scale. All statistical tests were two-sided and p50.05 was regarded as statistically significant.
Results A total of 53 patients were recruited and participated in the study. For demographic data, refer Table 1. Baseline assessment data of the participants is found in Table 2. Content validity A total of 47 different activities were stated in the PSFS and 45 of them (96%) were coded into activity level according to the ICF. Also, 29 (62%) could be found in the WOOS (Table 3). Concurrent validity Correlations between the PSFS and other measures were none to low (0.03 to 0.34; Table 2).
Table 2. Baseline data for 53 participants and Spearman correlations between the PSFS and other outcomes at baseline.
Ethics
PSFS total Spearman correlation (sign.)
Ethical approval was obtained from the regional ethic committee in Stockholm, reference number: 2009/318-31/2. Median (range)
Data analysis Data were stored in Excel and statistically analyzed using Statistica version 10 from StatsoftInc, Tulsa, OK. Descriptive statistics are presented as median, range for continuous variables and frequency and percentage for categorical variables. Content validity was described based on the activities stated in the PSFS, and thereafter coded according to the ICF coding rules into different components [33] by both authors together. The number of activities coded into the ICF activity component was counted, and to be deemed to assess activity, 590% of the activities stated in the PSFS should be coded into the ICF activity component. The activities stated in the PSFS were also compared to the activities in the WOOS, and an agreement of 50% was expected as the WOOS is not designed for humeral fracture assessment. Concurrent validity was calculated by the Spearman rank order correlation coefficient between PSFS and other variables, resulting in correlation coefficients (rs) between 1 and +1 [34,35]. The following reference levels for correlations were used: 0.00– 0.25 none or very low, 0.26–0.49 low, 0.50–0.69 moderate, 0.70– 0.89 high, 0.90–1.00 very high [36,37]. In most psychosocial variables, correlations commonly lies in the range 0.20–0.40, a level most often considered low in another context [35]. The strength of a correlation thus depends much on type of variables, and an absolute limit is difficult to state [35]. Due to the type of variables assessed in this study, correlations in the range 0.20–0.40 were expected. Sensitivity to change was calculated by the Sign test between follow-up and baseline scores, and between participants’ and physical therapists’ GRC (p50.05)
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a
PSFS total (0–10) Patient global score (0–100) Shoulder function assessment (5–30) Grip strength (N) WOOSb total (0–1900) Physical symptoms (0–600) Sports/recreation/work (0–500) Pain (0–100)
3 (0–8) 46 (0–93)
1.0 0.03 (ns)
20 (7–29)
0.32, p50.05
175 1030.5 272.5 291.5
(47–381) (300–1529.5) (79–541) (44–458)
50.5 (5–89.5)
0.25 (ns) 0.32, p50.05 0.33, p50.05 0.34, p50.05 0.14 (ns)
a
Patient specific functional scale (PSFS). Western Ontario Osteoarthritis of the shoulder Index (WOOS).
b
Table 3. Activities mentioned by at least 4 individuals in the PSFS, coded according to the ICF and compared to activities included in the WOOS. Activity
N
ICF Code
WOOS
Combing/washing/styling hair Reaching for objects above shoulder height Putting on clothes Doing housework (cleaning, doing laundry) Driving car Lifting and carrying objects Heavy gardening Hook a bra behind the back Hanging garments Bicycling
22 15 15 10 9 8 5 5 4 4
d5202 d430 d540 d640 d4751 d430 d6505 d540 d6400 d4750
Yes Yes Yes Yes No Yes Yes Yes Yes Yes
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Table 4. Sensitivity to change 22 participants measured before (median 1) and after 2 months of shoulder rehabilitation (median 2). Assessment PSFSa total Patient global score (0–100) Shoulder function assessment (5–30) Grip strength (N) WOOSb total (0–1900) WOOSb Physical symptoms (0–600) WOOSb Sports/recreation/work (0–500) Pain (0–100)
Median 1 2 45 19 215 1043 276 260.5 50.25
(0–8) (4–93) (10–28) (77–367) (300–1529.5) (79–541) (44–458) (6.5–89.5)
Median 2 9 16 7.5 254 359.5 102.75 114.5 13.5
(5–10) (1–74) (5–26) (105–406) (60.5–1199) (26–382) (13.5–321) (3–72)
p value 50.001 50.001 50.001 50.001 50.001 50.001 50.001 0.001
a
Patient Specific Functional Scale (PSFS). Western Ontario Osteoarthritis of the shoulder Index (WOOS).
b
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Sensitivity to change Twenty-two participants were included in the second assessment, after 2 months and 3 weeks of group shoulder rehabilitation. Median age of the 22 participants was 53.5 years, range (35–71), 12 were treated conservatively and 10 surgically. Five participants had collumchirurgicum fracture, two had tuberculummajus fracture, ten had a combination of collumchirurgicum and tuberculummajus fractures, and five had proximal humeral fracture. At re-assessment, 36% were on pain medication. The outcome in all variables was statistically significant and improved after shoulder rehabilitation, as was the PSFS (Table 4). There was total agreement (100%) between patients’ and physical therapists’ ratings of direction of outcome of rehabilitation in the GRC (better/worse/no change) and no systematic deviation could be detected between patients’ and physical therapists’ rating of level ( ± 0–7) of improvement (Sign test p ¼ 0.34). Internal consistency and outcome distribution The three questions of the PSFS contributed independently and significant to the total PSFS with the following correlations; PSFS median – PSFS 1: rs ¼ 0.75, PSFS median PSFS 2: rs ¼ 0.71 and PSFS median – PSFS 3: rs ¼ 0.65. A tendency towards floor effects could be seen in the total PSFS with a median score of 3 (range 0–8) and Q1 0–0, Q3 5–8. Also, 28% of the participants scored 0 in the total PSFS at baseline, indicating a severe activity limitation. At follow up, the ceiling effects were more evidently seen as the median score of PSFS total was 9 (range 5–10) with Q1 5–8, Q3 10–10, and 48% of the participants scored 10 which indicated no activity limitation at all.
Discussion The PSFS has very good content validity, as 96% of the stated activities could be classified in the ICF activity component and 62% were found in the WOOS. Concurrent validity was low, however the PSFS was highly sensitive to change after group rehabilitation once a week for 2–4 months. All three questions of the PSFS contributed to the total score, and both floor and ceiling effects could be noted. This is the first study to describe activity limitations that individuals with proximal humeral fracture experience early in the healing process. The activities that the participants stated in the PSFS sort under the component ‘‘activities and participation’’ in the ICF, except for one activity; sleeping which sorts under the component ‘‘body functions and body structures’’. Of all the 47 different activities, 29 (62%) could be found in the standardized questionnaire, the WOOS.
The results in this study are similar to the results in the study by Fairbairn et al., where 80% of all the activities collected by the PSFS were categorized into the ICF component ‘‘activities’’ and 7.7% were categorized into the ICF component ‘‘participation’’. In the same study, very few activities from the PSFS could be categorized under the ICF component ‘‘body function and body structure’’ [20]. In the Swedish study by Rosengren et al. [17], all the activities collected by the PSFS were categorized under the ICF component ‘‘activities’’. According to Fairbairn et al., one of the reasons that most of the activities in the PSFS ended up under the component ‘‘activities and participation’’ may be due to the standard question posed to the individual, as the question is directed to provide an activity and can thus provide a distortion of the response [20]. Of the instruments used in this study, the highest correlations were found between the PSFS and the WOOS, and between the PSFS and the shoulder function assessment, although the correlations were both low. The reason for the low correlations between the PSFS and the WOOS may be that the WOOS also raises other issues not related to the activity. For example, ‘‘How worried are you about what will happen with your shoulder in the future?’’ This can affect the total score of the WOOS and implicate other concerns that are not related to activity and thus not described in the PSFS. The low correlations can also be related to the possible floor effects in the PSFS, as can be seen in this study and has been described in earlier studies [10,17]. In the study by Chatman et al. [10], it was hypothesized that the PSFS provide correlations to other assessments between 0.30 and 0.50. Also, in the study by Westaway et al. [11], the correlations were assumed to be at a moderate level. The correlations in these studies were higher than expected, and are comparable to correlations between two instruments designed for the same purpose, known as disease specific measuring instruments [10,11]. In the current situation, there is no instrument appropriate for individuals with proximal humeral fractures which, at the same time, is also focused on the ICF dimension ‘‘activities and participation’’. This can explain the low correlations between the PSFS and other instruments used in this study compared to the studies by Chatman et al. and Westaway et al. In the study by Rosengren et al. [17], where the Swedish version of the PSFS was tested, no strong correlations between the PSFS and other measurements could be found. All the correlations were in the range of rs ¼ 0.20–0.50. Regarding internal consistency, correlations between the PSFS median score and the three questions were rs ¼ 0.75, 0.71 and 0.65, respectively. Based on this, one can argue if two activities would have been enough to describe these diagnoses, thus omitting the third question from the score. However, rs ¼ 0.65 is close to the expected level of rs ¼ 0.70 and therefore we argue that
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DOI: 10.3109/09638288.2015.1044623
the PSFS should be kept in its original form, based on three questions, when used in this diagnosis. We decided to limit this study to those participants who were treated conservatively or surgically with plate and screw or intramedullary nail, as these patients were rehabilitated in a similar manner and were in the same phase of the rehabilitation 6 weeks post-trauma or postoperatively. A weakness of the study is the sample method, and the lack of information about the external loss. At the start of the study, the goal was to have a consecutive sampling method. This proved not to be possible given that the study was conducted in parallel with the daily clinical work. One of the strengths of the study is that there is no internal loss to follow-up. The fact that five different physical therapists performed the measurements could lead to, despite co-training before the start of the study, different approaches to collecting data, which in turn may affect the results. Regarding generalizability, in this study, there are few men; only eight of the 53 participants are men. However, proximal humeral fractures are three times more common in women than in men [2,7,8]. Therefore, the participants can be considered representative for this diagnostic group. The median age of 60 years can be considered as a bit low as the group of patients is mainly dominated by individuals older than 60 years of age. This may be due to controlled selection related to the shoulder rehabilitation group primarily consisting of patients of working age. The data collection has only been performed on participants treated at Danderyd hospital in Stockholm, thus the sample should represent urbanites. These factors along with activity level, previous illnesses/diseases and profession (among those who were still working) can affect the results and especially the choice of activity in the PSFS, and are factors that were not registered in the background data. All of these factors should be recorded in future studies as they may affect the choice of activity and outcome.
Conclusion Based on our findings, we conclude that The PSFS assesses on activity level in patients with proximal humeral fracture and that The PSFS is sensitive to change for group rehabilitation after humeral fracture. Also, we consider the PSFS a useful tool for goal-setting, motivating and individually tailoring rehabilitation activities and suggest that The PSFS should be used in addition to specific measures of body functions and general health in rehabilitation after humeral fracture. However, most participants in this study are of working age and might thus have additional motivation for rehabilitation exercises. The measurement properties of the PSFS in older people and during home-based exercises after humeral fractures need to be described.
Acknowledgements We would like to acknowledge Suzanne Revay for participating in the beginning of data collection.
Declaration of interest None of the authors declare any conflict of interest. None of the authors have received any funding for this study
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ISSN: 0963-8288 (Print) 1464-5165 (Online) Journal homepage: http://www.tandfonline.com/loi/idre20
Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture Sara Mannberg Bäckman, Sara Stråt, Susanne Ahlström & Nina Brodin To cite this article: Sara Mannberg Bäckman, Sara Stråt, Susanne Ahlström & Nina Brodin (2015): Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture, Disability and Rehabilitation To link to this article: http://dx.doi.org/10.3109/09638288.2015.1044623
Published online: 11 May 2015.
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http://informahealthcare.com/dre ISSN 0963-8288 print/ISSN 1464-5165 online Disabil Rehabil, Early Online: 1–6 ! 2015 Informa UK Ltd. DOI: 10.3109/09638288.2015.1044623
RESEARCH PAPER
Validity and sensitivity to change of the Patient Specific Functional Scale used during rehabilitation following proximal humeral fracture Sara Mannberg Ba¨ckman1, Sara Stra˚t1, Susanne Ahlstro¨m1, and Nina Brodin1,2 Division of Physiotherapy, Orthopaedic Clinic, Danderyd Hospital, Stockholm, Sweden and 2Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm, Sweden
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Abstract
Keywords
Purpose: To describe content validity, concurrent validity, sensitivity to change, internal consistency and the outcome distribution of the Patient Specific Functional Scale (PSFS) in patients with proximal humeral fracture. Method: Fifty-three patients with proximal humeral fracture treated conservatively or surgically with plate and screw or intramedullary nail were recruited 6 weeks (±1 week) post-trauma or post-surgery. The following assessments were used: the PSFS, patient global score, shoulder function assessment, grip strength and Western Ontario Osteoarthritis of the shoulder Index (WOOS), before start of (n ¼ 53) and after (n ¼ 22) 2–3 months of group rehabilitation. Results: In total, 96% of the activities stated in the PSFS was classified in the International Classification of Functioning, Disability and Health activity component and 62% were found in the WOOS. Correlations between measures were low. The PSFS was highly sensitive to change to a period of group rehabilitation. All questions of the PSFS contributed to the total score. Both floor and ceiling effects could be noted. Conclusion: The PSFS shows satisfying measurement properties and may be a useful complement in the evaluation of individual changes during a period of rehabilitation after proximal humeral fracture.
ICF, measurement, patient preference, rehabilitation History Received 13 October 2014 Revised 16 April 2015 Accepted 21 April 2015 Published online 11 May 2015
ä Implications for Rehabilitation
The PSFS assesses on activity level in patients with proximal humeral fracture. The PSFS is sensitive to change for group rehabilitation after humeral fracture. The PSFS can be useful for goal-setting, motivating and individually tailoring rehabilitation activities. The PSFS should be used in addition to specific measures of body functions and general health.
Introduction Of all fractures treated in orthopedic clinics, approximately 4–5% are proximal humeral fractures [1–5]. Proximal humeral fracture is the third most common fracture among elderly people following proximal femur fracture and distal radius fracture [6]. Approximately 75% of all who incur a proximal humeral fracture are over 60 years of age, and the fracture type is three times more common among women than men [2,7,8]. Almost all proximal humeral fractures are minimally displaced and can therefore be treated conservatively with early movement training and usually with satisfying results [3,5,7–9]. Several studies show that more complex proximal humeral fractures with three or more parts in
Address for correspondence: Nina Brodin, Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institute, 23 100, S 141 83 Huddinge, Sweden. Tel: +46 8 524 88843. Fax: +46 8 524 88813. E-mail: [email protected]
healthy and active patients should be treated surgically to optimize shoulder function [7–9]. After a proximal humeral fracture, a concerted effort by the patient, surgeon and physical therapist is required for the patient to regain good functionality of the shoulder joint [8]. A dilemma in rehabilitation is that early and aggressive mobilization can lead to the fracture healing the wrong way or not healing at all, while a too long immobilization can lead to stiffness and contracture. Individually tailored and graded exercise until full functional mobility in the shoulder joint has been achieved is the foundation of successful rehabilitation after both conservatively and operatively treated proximal humeral fracture [8]. Six to eight weeks post-operatively or post-trauma, both operatively and conservatively treated patients perform active range of motion exercises and resistance training with light weights [8]. Individually tailored exercise based on activity limitations stated by the patient can improve adherence to rehabilitation. It also seems more meaningful to strive for and achieve personally
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set goals [10,11]. Pre-defined questionnaires and/or general scales might include several parts that do not provide answers to the patient’s specific problem. A patient-specific instrument, on the other hand, can record and evaluate changes on individual patient level. Selected activities are therefore relevant and meaningful to the patient [10,12–15]. The Patient-Specific Functional Scale (PSFS) was developed by physical therapists in Canada [14], and focuses on the patient’s own perceived activity limitations. The patient is asked about current functional status instead of being asked about changes in functionality, as in many other instruments [10,11,14]. The measurements properties of the Canadian version of the PSFS have been described in studies on patients with lower back pain, knee dysfunction, neck dysfunction, cervical radiculopathy and in patients with upper extremity musculoskeletal problems. In all these studies, the PSFS has proven valid and reliable [10,11,14– 16]. A Swedish translation of the instrument has been made by Broberg, Johansson and Roos, which was updated in 2005. The translation is distributed by the Swedish Association of Registered Physical therapists (LSR) (http://www.sjukgymnastforbundet.se/ lsr_old_asp/matmetoder/index.asp). The Swedish version of the PSFS has been tested in patients with surgically treated carpometacarpal joint osteoarthritis [17], showing very good content validity and good reliability. When assessing and evaluating rehabilitation in a clinical setting, a common framework such as the ‘‘International Classification of Functioning, Disability and Health’’ (ICF) can be useful. The ICF is a classification as well as a model, where the classification part consists of a number of different factors which in turn can be used in different approaches to describe an individual’s ability to function [18,19]. Using the ICF coding rules, information can be coded in various items, contributing to a more secure way to determine the level of which a method assesses [18]. In a study by Fairbairn et al. [20], all activities described in the PSFS were coded according to the ICF coding rules. Of all the activities that were coded, 80% could be categorized in the ICF component ‘‘Activities’’. In a similar study by Rosengren et al. [17], 100% of the activities were categorized in the ICF component ‘‘activities’’. There is currently no specific measure of activity limitation directed towards proximal humeral fractures, and no patientspecific functional assessment instrument has been tested on this group of patients according to validity and reliability requirements. The use of the PSFS can lead to greater understanding, refined planning and structure of the rehabilitation. If used in assessment of rehabilitation, it might increase the patient’s feeling of participation in the rehabilitation and motivate towards reaching personal goals. The PSFS is time-efficient and easy to manage. It is therefore interesting to test the PSFS in this particular group of patients to assess its usefulness for the individual, as well as for the evaluation of an entire period of rehabilitation. The purpose of this study was to describe content validity, concurrent validity, sensitivity to change, internal consistency and the outcome distribution of the PSFS in patients with proximal humeral fracture.
Methods Patients A total of 53 patients were included in the study, and the recruitment was based on convenience (Table 1). Assessments were performed in 3.5 years during 2008–2012. Inclusion criteria were: patients with proximal humeral fracture treated conservatively or surgically with plate and screw or intramedullary nail, 6 weeks (±1 week) post-trauma or post-operatively. Exclusion
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criteria were: (a) difficulties understanding and speaking Swedish, (b) cognitive limitations affecting the ability to follow instructions and to fill out questionnaires, (c) patients with proximal humeral fracture treated surgically with any type of shoulder prosthetic, cerclage or screw, (d) other acute or disabling injuries in the same arm. Demographic data collected from each patient were: sex, age, hand dominance, injured side, and amount and type of pain medication. Type of fracture and type of treatment were collected from the patient’s medical record (Table 1). Study protocol Patients were recruited at a physical therapist appointment during a scheduled visit at the orthopedic clinic 6 weeks (±1 week) posttrauma or post-operatively. Patients were asked to give a written consent after they had received oral and written information about the study and had agreed to participate. The five physical therapists that were collecting data had at least 3 years of experience working with this type of patients, and they were all co-trained, before the study started, in how all the assessments should be performed. A separate study protocol was kept for each patient, respectively. Assessments were performed in the following order: demographic data, the PSFS [10,11,16], patient global score (PGS) [21,22], shoulder function assessment [23–25], grip strength (Grippit) [24,26,27] and Western Ontario Osteoarthritis of the Shoulder Index (WOOS) [28,29]. Assessments took 15–25 min and were performed in connection to a regular visit at the physical therapist. The second assessment was performed after 2–4 months of shoulder rehabilitation (once a week). Dose and type of pain medication, the PSFS (rating of the same activities chosen at the first test session), PGS, shoulder function assessment, Grippit, WOOS and Global Rating of Change Scale (GRC) were then assessed. Assessments The following assessments were used. The PSFS is a patientspecific self-report instrument where the patient is asked to state three activities currently difficult or impossible to perform due to the injury, symptom or illness [10,11,16]. The difficulty of performing each activity is rated on an 11 point scale, 0–10, were 0 is ‘‘Unable to perform activity’’ and 10 is ‘‘Able to perform activity at same level as before injury or problem’’. The PSFS takes about four minutes to perform, and a change of two steps or more is considered to represent a clinically relevant change [14]. The patient global score (PGS) is a self-report instrument to evaluate general wellbeing. On a 100 mm Visual Analog Scale (VAS), were 0 is ‘‘worst wellbeing’’ and 100 is ‘‘best wellbeing’’, the patient is asked to rate their general wellbeing, considering the current injury [21,22]. The shoulder function assessment ad modum Bostro¨m is developed for use in rheumatic diseases, but is also frequently used within orthopedic rehabilitation. The assessment include five functional tasks; hand-to-ceiling, hand-to-opposite-shoulder, Table 1. Demographics of 53 participants with humeral fracture. Gender, male/female (n) Age, years, median (range) Injured dominant side (%) Conservative/surgical treatment (n) Collum chirurgicum fracture (n) Tuberculum majus fracture (n) Combinated collum chirurgicum/tuberculum majus fracture (n) Proximal humeral fracture (n) On current pain medication (%)
8/45 60 (34–77) 51 27/26 10 5 22 16 83
Validation of PSFS for humeral fracture
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hand-to-neck, hand-to-back and hand-to-sacrum. Each task is scored on a six-grade scale from 1 to 6 where 1 indicates a severe disability and 6 normal function. In the current study, the scale was reversed to better fit with the remaining assessments [23–25]. Grip strength (Grippit, AB Detektor, Go¨teborg, Sweden) is an electronic device assessing the maximal isometric grip strength in Newton (N). Patients were asked to sit in an upright position with their arm and hand in a standard position. Thereafter, the patients were asked to press together/grip around a handle, as hard as possible, during the 10 s test [24,26,27]. The Western Ontario Osteoarthritis of the Shoulder index (WOOS), is a diagnosis specific measurement for evaluating the quality of life in relation to shoulder function of symptomatic primary osteoarthritis of the shoulder. The WOOS consists of 19 statements, divided in to four categories: (a) physical symptoms, (b) sports/recreation/work, (c) lifestyle, (d) emotions. The patients answer each question by marking on a 100 mm visual analog scale (VAS). The WOOS ranges from 0 to 1900 where 0 represents no symptoms/best quality of life [28,29]. A Swedish version of the ¨ berg and WOOS translated by Hultenheim Klintberg [30], Lind, O Lillkrona is available from the Swedish Shoulder and Elbow Society (SSAS) [31]. The global rating of change scale (GRC) was used at the second assessment only. The GRC scale consists of two parts, where each part starts with a question regarding direction of change (better/worse/no change) and is then scored on a 15 point scale ranging from +7 (indicating improvement) to 7 (indicating impairment). The first part asks about the magnitude of change and the second part asks about the importance of change. Only the question regarding magnitude of the GRC was used in this study, and was answered by both the participants and their physical therapist, each unaware of the other persons answer [10,32].
regarding both direction (better/worse/no change) and level (±0–7). Internal consistency of the PSFS was estimated using the Spearman correlation between PSFS median and the three questions independently. This was done to assure that no question was abstracted from the other three, and that all questions contributed to the total sore. A Spearman correlation of approximately rs ¼ 0.70 was expected between all three questions, respectively. Outcome distribution regarding floor and/or ceiling effects of the PSFS was described by median along with interquartile range (Q1–Q3), and the percentage of participants’ ratings in the bottom or top of the scale. All statistical tests were two-sided and p50.05 was regarded as statistically significant.
Results A total of 53 patients were recruited and participated in the study. For demographic data, refer Table 1. Baseline assessment data of the participants is found in Table 2. Content validity A total of 47 different activities were stated in the PSFS and 45 of them (96%) were coded into activity level according to the ICF. Also, 29 (62%) could be found in the WOOS (Table 3). Concurrent validity Correlations between the PSFS and other measures were none to low (0.03 to 0.34; Table 2).
Table 2. Baseline data for 53 participants and Spearman correlations between the PSFS and other outcomes at baseline.
Ethics
PSFS total Spearman correlation (sign.)
Ethical approval was obtained from the regional ethic committee in Stockholm, reference number: 2009/318-31/2. Median (range)
Data analysis Data were stored in Excel and statistically analyzed using Statistica version 10 from StatsoftInc, Tulsa, OK. Descriptive statistics are presented as median, range for continuous variables and frequency and percentage for categorical variables. Content validity was described based on the activities stated in the PSFS, and thereafter coded according to the ICF coding rules into different components [33] by both authors together. The number of activities coded into the ICF activity component was counted, and to be deemed to assess activity, 590% of the activities stated in the PSFS should be coded into the ICF activity component. The activities stated in the PSFS were also compared to the activities in the WOOS, and an agreement of 50% was expected as the WOOS is not designed for humeral fracture assessment. Concurrent validity was calculated by the Spearman rank order correlation coefficient between PSFS and other variables, resulting in correlation coefficients (rs) between 1 and +1 [34,35]. The following reference levels for correlations were used: 0.00– 0.25 none or very low, 0.26–0.49 low, 0.50–0.69 moderate, 0.70– 0.89 high, 0.90–1.00 very high [36,37]. In most psychosocial variables, correlations commonly lies in the range 0.20–0.40, a level most often considered low in another context [35]. The strength of a correlation thus depends much on type of variables, and an absolute limit is difficult to state [35]. Due to the type of variables assessed in this study, correlations in the range 0.20–0.40 were expected. Sensitivity to change was calculated by the Sign test between follow-up and baseline scores, and between participants’ and physical therapists’ GRC (p50.05)
3
a
PSFS total (0–10) Patient global score (0–100) Shoulder function assessment (5–30) Grip strength (N) WOOSb total (0–1900) Physical symptoms (0–600) Sports/recreation/work (0–500) Pain (0–100)
3 (0–8) 46 (0–93)
1.0 0.03 (ns)
20 (7–29)
0.32, p50.05
175 1030.5 272.5 291.5
(47–381) (300–1529.5) (79–541) (44–458)
50.5 (5–89.5)
0.25 (ns) 0.32, p50.05 0.33, p50.05 0.34, p50.05 0.14 (ns)
a
Patient specific functional scale (PSFS). Western Ontario Osteoarthritis of the shoulder Index (WOOS).
b
Table 3. Activities mentioned by at least 4 individuals in the PSFS, coded according to the ICF and compared to activities included in the WOOS. Activity
N
ICF Code
WOOS
Combing/washing/styling hair Reaching for objects above shoulder height Putting on clothes Doing housework (cleaning, doing laundry) Driving car Lifting and carrying objects Heavy gardening Hook a bra behind the back Hanging garments Bicycling
22 15 15 10 9 8 5 5 4 4
d5202 d430 d540 d640 d4751 d430 d6505 d540 d6400 d4750
Yes Yes Yes Yes No Yes Yes Yes Yes Yes
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Table 4. Sensitivity to change 22 participants measured before (median 1) and after 2 months of shoulder rehabilitation (median 2). Assessment PSFSa total Patient global score (0–100) Shoulder function assessment (5–30) Grip strength (N) WOOSb total (0–1900) WOOSb Physical symptoms (0–600) WOOSb Sports/recreation/work (0–500) Pain (0–100)
Median 1 2 45 19 215 1043 276 260.5 50.25
(0–8) (4–93) (10–28) (77–367) (300–1529.5) (79–541) (44–458) (6.5–89.5)
Median 2 9 16 7.5 254 359.5 102.75 114.5 13.5
(5–10) (1–74) (5–26) (105–406) (60.5–1199) (26–382) (13.5–321) (3–72)
p value 50.001 50.001 50.001 50.001 50.001 50.001 50.001 0.001
a
Patient Specific Functional Scale (PSFS). Western Ontario Osteoarthritis of the shoulder Index (WOOS).
b
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Sensitivity to change Twenty-two participants were included in the second assessment, after 2 months and 3 weeks of group shoulder rehabilitation. Median age of the 22 participants was 53.5 years, range (35–71), 12 were treated conservatively and 10 surgically. Five participants had collumchirurgicum fracture, two had tuberculummajus fracture, ten had a combination of collumchirurgicum and tuberculummajus fractures, and five had proximal humeral fracture. At re-assessment, 36% were on pain medication. The outcome in all variables was statistically significant and improved after shoulder rehabilitation, as was the PSFS (Table 4). There was total agreement (100%) between patients’ and physical therapists’ ratings of direction of outcome of rehabilitation in the GRC (better/worse/no change) and no systematic deviation could be detected between patients’ and physical therapists’ rating of level ( ± 0–7) of improvement (Sign test p ¼ 0.34). Internal consistency and outcome distribution The three questions of the PSFS contributed independently and significant to the total PSFS with the following correlations; PSFS median – PSFS 1: rs ¼ 0.75, PSFS median PSFS 2: rs ¼ 0.71 and PSFS median – PSFS 3: rs ¼ 0.65. A tendency towards floor effects could be seen in the total PSFS with a median score of 3 (range 0–8) and Q1 0–0, Q3 5–8. Also, 28% of the participants scored 0 in the total PSFS at baseline, indicating a severe activity limitation. At follow up, the ceiling effects were more evidently seen as the median score of PSFS total was 9 (range 5–10) with Q1 5–8, Q3 10–10, and 48% of the participants scored 10 which indicated no activity limitation at all.
Discussion The PSFS has very good content validity, as 96% of the stated activities could be classified in the ICF activity component and 62% were found in the WOOS. Concurrent validity was low, however the PSFS was highly sensitive to change after group rehabilitation once a week for 2–4 months. All three questions of the PSFS contributed to the total score, and both floor and ceiling effects could be noted. This is the first study to describe activity limitations that individuals with proximal humeral fracture experience early in the healing process. The activities that the participants stated in the PSFS sort under the component ‘‘activities and participation’’ in the ICF, except for one activity; sleeping which sorts under the component ‘‘body functions and body structures’’. Of all the 47 different activities, 29 (62%) could be found in the standardized questionnaire, the WOOS.
The results in this study are similar to the results in the study by Fairbairn et al., where 80% of all the activities collected by the PSFS were categorized into the ICF component ‘‘activities’’ and 7.7% were categorized into the ICF component ‘‘participation’’. In the same study, very few activities from the PSFS could be categorized under the ICF component ‘‘body function and body structure’’ [20]. In the Swedish study by Rosengren et al. [17], all the activities collected by the PSFS were categorized under the ICF component ‘‘activities’’. According to Fairbairn et al., one of the reasons that most of the activities in the PSFS ended up under the component ‘‘activities and participation’’ may be due to the standard question posed to the individual, as the question is directed to provide an activity and can thus provide a distortion of the response [20]. Of the instruments used in this study, the highest correlations were found between the PSFS and the WOOS, and between the PSFS and the shoulder function assessment, although the correlations were both low. The reason for the low correlations between the PSFS and the WOOS may be that the WOOS also raises other issues not related to the activity. For example, ‘‘How worried are you about what will happen with your shoulder in the future?’’ This can affect the total score of the WOOS and implicate other concerns that are not related to activity and thus not described in the PSFS. The low correlations can also be related to the possible floor effects in the PSFS, as can be seen in this study and has been described in earlier studies [10,17]. In the study by Chatman et al. [10], it was hypothesized that the PSFS provide correlations to other assessments between 0.30 and 0.50. Also, in the study by Westaway et al. [11], the correlations were assumed to be at a moderate level. The correlations in these studies were higher than expected, and are comparable to correlations between two instruments designed for the same purpose, known as disease specific measuring instruments [10,11]. In the current situation, there is no instrument appropriate for individuals with proximal humeral fractures which, at the same time, is also focused on the ICF dimension ‘‘activities and participation’’. This can explain the low correlations between the PSFS and other instruments used in this study compared to the studies by Chatman et al. and Westaway et al. In the study by Rosengren et al. [17], where the Swedish version of the PSFS was tested, no strong correlations between the PSFS and other measurements could be found. All the correlations were in the range of rs ¼ 0.20–0.50. Regarding internal consistency, correlations between the PSFS median score and the three questions were rs ¼ 0.75, 0.71 and 0.65, respectively. Based on this, one can argue if two activities would have been enough to describe these diagnoses, thus omitting the third question from the score. However, rs ¼ 0.65 is close to the expected level of rs ¼ 0.70 and therefore we argue that
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the PSFS should be kept in its original form, based on three questions, when used in this diagnosis. We decided to limit this study to those participants who were treated conservatively or surgically with plate and screw or intramedullary nail, as these patients were rehabilitated in a similar manner and were in the same phase of the rehabilitation 6 weeks post-trauma or postoperatively. A weakness of the study is the sample method, and the lack of information about the external loss. At the start of the study, the goal was to have a consecutive sampling method. This proved not to be possible given that the study was conducted in parallel with the daily clinical work. One of the strengths of the study is that there is no internal loss to follow-up. The fact that five different physical therapists performed the measurements could lead to, despite co-training before the start of the study, different approaches to collecting data, which in turn may affect the results. Regarding generalizability, in this study, there are few men; only eight of the 53 participants are men. However, proximal humeral fractures are three times more common in women than in men [2,7,8]. Therefore, the participants can be considered representative for this diagnostic group. The median age of 60 years can be considered as a bit low as the group of patients is mainly dominated by individuals older than 60 years of age. This may be due to controlled selection related to the shoulder rehabilitation group primarily consisting of patients of working age. The data collection has only been performed on participants treated at Danderyd hospital in Stockholm, thus the sample should represent urbanites. These factors along with activity level, previous illnesses/diseases and profession (among those who were still working) can affect the results and especially the choice of activity in the PSFS, and are factors that were not registered in the background data. All of these factors should be recorded in future studies as they may affect the choice of activity and outcome.
Conclusion Based on our findings, we conclude that The PSFS assesses on activity level in patients with proximal humeral fracture and that The PSFS is sensitive to change for group rehabilitation after humeral fracture. Also, we consider the PSFS a useful tool for goal-setting, motivating and individually tailoring rehabilitation activities and suggest that The PSFS should be used in addition to specific measures of body functions and general health in rehabilitation after humeral fracture. However, most participants in this study are of working age and might thus have additional motivation for rehabilitation exercises. The measurement properties of the PSFS in older people and during home-based exercises after humeral fractures need to be described.
Acknowledgements We would like to acknowledge Suzanne Revay for participating in the beginning of data collection.
Declaration of interest None of the authors declare any conflict of interest. None of the authors have received any funding for this study
References 1. Horak J, Nilsson BE. Epidemiology of fracture of the upper end of the humerus. Clin Orthop Relat Res 1975;112:250–3. 2. Lind T, Krøner K, Jensen J. The epidemiology of fractures of the proximal humerus. Arch Orthop Trauma Surg 1989;108:285–7. 3. Zyto K, Ahrengart L, Sperber A, To¨rnkvist H. Treatment of displaced proximal humeral fractures in elderly patients. J Bone Joint Surg Br 1997;79:412–17.
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