predictors of chronic ankle instability after an index lateral ankle sprain: a systematic review
TRANSCRIPT
Accepted Manuscript
Title: Predictors of chronic ankle instability after an indexlateral ankle sprain: A systematic review
Author: Fereshteh Pourkazemi Claire E. Hiller JacquelineRaymond Elizabeth J. Nightingale Kathryn M. Refshauge
PII: S1440-2440(14)00024-3DOI: http://dx.doi.org/doi:10.1016/j.jsams.2014.01.005Reference: JSAMS 989
To appear in: Journal of Science and Medicine in Sport
Received date: 8-12-2013Accepted date: 25-1-2014
Please cite this article as: Pourkazemi F, Hiller CE, Raymond J, Nightingale EJ,Refshauge KM, Predictors of chronic ankle instability after an index lateral anklesprain: A systematic review, Journal of Science and Medicine in Sport (2014),http://dx.doi.org/10.1016/j.jsams.2014.01.005
This is a PDF file of an unedited manuscript that has been accepted for publication.As a service to our customers we are providing this early version of the manuscript.The manuscript will undergo copyediting, typesetting, and review of the resulting proofbefore it is published in its final form. Please note that during the production processerrors may be discovered which could affect the content, and all legal disclaimers thatapply to the journal pertain.
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Predictors of chronic ankle instability after an index lateral ankle sprain: A systematic 1
review 2
3
Fereshteh Pourkazemi,a Claire E. Hiller,a Jacqueline Raymond,b Elizabeth J Nightingale,a Kathryn M. 4
Refshauge a 5
6
a Discipline of Physiotherapy, Faculty of Health Sciences, University of Sydney, Australia 7
b Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Australia 8
9
Corresponding author: Fereshteh Pourkazemi 10
e-mail: [email protected] 11
12
Word count: 3037 13
The Abstract word count: 234 14
Number of tables: 2 15
Number of figures: 1 16
Supplemental files: 2 17
18
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Predictors of chronic ankle instability after an index lateral ankle sprain: A systematic 18
review 19
20
Abstract 21
Objective: To identify the predictors of CAI after an index lateral ankle sprain. 22
Design: Systematic review 23
Methods: The data bases of MEDLINE, CINAHL, AMED, Scopus, SPORTDiscus, Embase, Web of 24
Science, PubMed, PEDro, and Cochrane Register of Clinical Trials were searched from the earliest 25
record until May 2013. Prospective studies investigating any potential intrinsic predictors of chronic 26
ankle instability (CAI) after an index ankle sprain were included. Eligible studies had a prospective 27
design (follow-up of at least three months), participants of any age with an index ankle sprain, and 28
had assessed ongoing impairments associated with CAI. Eligible studies were screened and data 29
extracted by two independent reviewers. 30
Results: Four studies were included. Three potential predictors of CAI, i.e., postural control, 31
perceived instability, and severity of the index sprain, were investigated. Decreased postural control 32
measured by number of foot lifts during single-leg stance with eyes closed and perceived instability 33
measured by Cumberland Ankle Instability Tool (CAIT) were not predictors of CAI. While the results 34
of one study showed that the severity of the initial sprain was a predictor of re-sprain, another study 35
did not. 36
Conclusion: Of the three investigated potential predictors of CAI after an index ankle sprain, only 37
severity of initial sprain (grade II) predicted re-sprain. However, concerns about validity of the 38
grading system suggest that these findings should be interpreted with caution. 39
Key words: ankle sprains, joint instability, sprain severity, postural balance 40
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1. Introduction 42
43
Ankle sprain injuries, particularly sprain of the lateral ligaments, are among the most common lower 44
limb injuries in the general1,2 and athletic populations3 as well as among military personnel.4 High 45
recurrence rate, along with residual impairments, are the consequence of ankle sprain for up to 54% of 46
individuals.5 The most common residual impairments include re-sprain, perceived instability and 47
episodes of giving way (also referred to as functional instability), joint laxity (also referred to as 48
mechanical instability), pain, swelling, a feeling of weakness and subsequently reduced level of 49
physical activity.5 These residual impairments, alone or in combination, are frequently termed chronic 50
ankle instability (CAI).6 Prevention of CAI, particularly re-sprain, is the main treatment goal for many 51
studies of ankle sprain,7 however, prevention is only possible if people at risk of developing CAI can 52
be identified. That is, to determine the most effective prevention strategy it is essential to understand 53
the underlying causes leading to CAI, and the factors increasing the risk of CAI. 54
History of a previous sprain is the most frequently reported risk factor for lateral sprain.8-10 Basketball 55
players with history of an ankle sprain were found to be five times more likely to re-sprain, although 56
the reasons for the increased risk are unknown.9 Hertel11 suggested that ankle sprains cause various 57
sensorimotor deficits that can lead to instability, and that the presence of instability increases the risk 58
of further sprain. Many studies have investigated this theory, but the findings are inconsistent.12-14 59
There are few studies of predictors of CAI, however two systematic reviews have evaluated closely 60
related questions and some information can be derived from their findings. One systematic review 61
found decreased dorsiflexion range of motion to be a strong predictor of lateral ankle sprain.15 The 62
second systematic review investigated the clinical course of acute ankle sprain,5 finding only one 63
study that reported on prognostic factors for development of CAI16. Based on this study,16 athletes 64
competing at a higher level of competition were at greater risk of persisting impairments after an 65
acute sprain than athletes competing at lower levels. Severity of pain, number of re-sprains, as well as 66
level of perceived instability and self-reported recovery after an acute lateral ankle sprain were found 67
to be independent of the severity of the initial sprain. Furthermore, men were reported to have a 68
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greater risk of developing residual impairments than women. However, not all studies included in 69
these two systematic reviews investigated the risk factors contributing to CAI after an index ankle 70
sprain. 71
Research to date has tended to focus more on changes associated with CAI rather than predictors of 72
CAI. Sensorimotor, functional, anatomical or biomechanical changes associated with CAI have been 73
analysed in a number of systematic reviews.14,17,18 Postural instability,17,18 prolonged time to balance 74
after a jump,14 lower limb muscle weakness or muscle imbalance19 were found to be associated with 75
CAI. Whether these impairments cause CAI or develop as a result of CAI is not clear. Therefore, the 76
objective of the present systematic review was to identify predictors of CAI (e.g., age, sex, body mass 77
index (BMI), level of physical activity, balance, postural control, proprioception, motor control, 78
severity of ankle sprain, perceived ankle instability, feeling of giving way, ligament laxity, pain, or 79
swelling) after an index ankle sprain. Prospective studies investigating any of these variables as 80
potential predictors of CAI after an index ankle sprain might enable health providers to design more 81
effective treatments to prevent ongoing problems. 82
83
2. Methods 84
85
The study protocol was developed based on the framework outlined in the guidelines provided by the 86
PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement.20 The 87
protocol of this systematic review is registered on PROSPERO (registration number 88
CRD42012002990). 89
2.1. Eligibility criteria 90
Studies were included if they met the following inclusion criteria: i) longitudinal design, ii) follow-up 91
length of at least three months since the sprain, iii) participants of any age who had sustained an index 92
ankle sprain only, iv) measuring at least one of the potential predictors of CAI, v) reporting on any re-93
sprain or residual symptoms after the initial ankle sprain during the follow-up period, vi) published 94
full paper; abstracts were included if the authors provided the raw data for further analysis. Papers 95
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where it was possible that at least some of the participants had suffered an index sprain were 96
considered for inclusion, however if the data from this sub-group could not be isolated, then the paper 97
was excluded. 98
For randomised controlled trials, we included the minimal intervention group (e.g. conservative 99
treatment of lateral ankle sprains, such as modified footwear and associated supports, taping, adapted 100
training programmes, and education). Randomised clinical trials were excluded if there was no 101
minimal intervention group e.g., if surgery or immobilisation for more than three days were 102
investigated. 103
2.2. Information Sources 104
Studies were identified through a search of the MEDLINE, CINAHL, AMED, Scopus, 105
SPORTDiscus, Embase, Web of Science, PubMed, PEDro, and Cochrane Register of Clinical Trials 106
to May 2013. Abstracts from the International Ankle Symposium (IAS) and International Foot and 107
Ankle Biomechanics (i-FAB) conference proceedings, and bibliographies of eligible studies were 108
hand searched. In addition, relevant experts were contacted to identify any unpublished studies that 109
may exist and to review the list of identified studies for completeness. No language restriction was 110
imposed, however, if a translation could not be arranged, the paper was excluded. 111
2.3. Search Strategy 112
Key terms used in our search strategy are presented in supplemental file 1. Search protocols were 113
specifically designed to target prospective studies. 114
2.4. Study Selection 115
All studies identified by the search strategy were screened against the eligibility criteria independently 116
by the first author (FP) and by one other author (CH, JR or KR). Titles and abstracts were inspected 117
and clearly ineligible studies were removed. Full copies of potentially eligible papers were retrieved. 118
Any inconsistencies regarding inclusion of trials were resolved by consensus. 119
2.5. Potential Predictors of CAI 120
The following predictors, identified from previous studies of risk factors for lateral ankle sprain, were 121
considered as potential risk factors of developing CAI: age, sex, height, weight, BMI, leg dominance, 122
foot type, foot and lower limb alignment, ankle joint laxity, general ligamentous laxity, postural 123
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control, muscle weakness or muscle strength/power imbalance in lower limbs, lower limb muscle 124
reaction time, range of motion at lower limb joints, physical fitness, gait biomechanics, and severity 125
of symptoms after the initial sprain (e.g., pain, swelling, laxity, feeling of instability). 126
2.6. Outcome measures 127
Any measures that assessed ongoing impairments associated with CAI after the initial sprain during 128
the follow up period (e.g., re-sprain, swelling, pain, mechanical instability, perceived instability, 129
feeling of giving way, or feeling of weakness) were considered as outcome measures. 130
2.7. Data Extraction Process 131
Data were extracted independently by two authors (FP and CH) and confirmed by one other author 132
(either JR or KR). Any discrepancies were settled by further discussion and consensus. Study 133
characteristics extracted were study type, target population (setting, sex, age), sample size, inclusion 134
criteria, follow-up duration, prognostic factors measured, interventions (if any) and all reported 135
outcome measures. 136
2.8. Quality Assessment 137
Risk of bias and methodological quality of included studies were assessed using the quality 138
assessment tool developed by Pengel21 et al. This tool consists of 7 items rated as either ‘yes’, ‘no’ or 139
‘N/A’ (not applicable). Four items relate to control of bias (items 1-4), two to appropriate 140
measurement of variables (items 5 and 6) and one to control of confounding variables (item 7). Two 141
raters (FP and JR) independently assessed the quality and a third author (CH) resolved disagreements. 142
2.9. Synthesis of Results 143
Study outcomes were statistically pooled if the studies were considered to be sufficiently 144
homogeneous. For homogeneous studies, raw data were used in a direct logistic regression to assess 145
whether the predictor variables increased the likelihood of re-sprain. If the studies were considered 146
too heterogeneous, data were not pooled and the outcomes were described. 147
148
149
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149
3. Results 150
151
The search strategy identified 8085 titles. Following title and abstract screening, 210 potentially 152
relevant articles were identified, of which 16 met all the inclusion criteria. The data required for 153
analysis were reported in two of the included studies.22,23 The authors of the remaining 14 articles, 154
which included participants with one or more ankle sprains, were contacted for data related to the 155
participants with only an index ankle sprain. Seven authors replied, of whom only two were able to 156
provide raw data for analysis.24,25 Therefore, four studies22-25 were included in this review (Figure 1). 157
3.1. Study Characteristics 158
All included studies were prospective cohort trials, with follow-up periods that varied between 8 and 159
24 months. Participants were adults in two studies,23,24 adolescents in one study25 and children and 160
adolescents in the fourth study.22 In two studies the inclusion criterion was an acute index ankle sprain 161
of less than two days duration.22,23 The other two studies24,25 included a heterogeneous group of 162
participants, with a history that varied between multiple ankle sprains to no history of sprain, and the 163
time since sprain was not standardised. Separate data of the participants with an index ankle sprain 164
were provided by the authors of these two studies.24,25 Participants were recruited from various 165
settings, including a university,24 dance school,25 and primary care practice(s).22,23 The predictors of 166
CAI measured were perceived instability and balance24,25 in two of the studies and severity of index 167
sprain22,23 in the other two. The severity of injury was measured by either clinical symptoms and 168
anterior drawer stress x-ray23 or clinical symptoms and magnetic resonance imaging (MRI).22 The 169
outcomes reported were re-sprain in three studies23-25 and pain, mobility and perceived instability in 170
the remaining study.22 Details of the included studies are presented in Table 1. 171
3.2. Quality Assessment 172
No study was rated as having excellent methodological quality. Methodological quality was moderate 173
in three studies, with scores of 5 25 and 4.23,24 The fourth study22 had low methodological quality, with 174
a score of 3 (supplemental file 2).None of these studies used statistical adjustment for potentially 175
confounding factors. Only one study used blinded outcome assessor(s).22 176
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3.4. Predictive Factors of CAI 178
Data for two of the studies24,25 were pooled, because they investigated perceived instability and 179
balance as predictors for re-sprain. We were not able to pool data for the two other studies22,23 180
because, although they both investigated severity of initial sprain, they used different grading systems 181
and reported on different outcome measures. 182
Perceived instability and balance: Two studies24,25 investigated perceived instability and static balance 183
on both legs as a predictor of re-sprain. Perceived instability was measured using the Cumberland 184
Ankle Instability Tool (CAIT) and balance was measured recording the number of foot movements 185
during single-leg stance with eyes closed for 30 seconds. Hiller25 et al and de Noronha24 et al provided 186
raw data for 44 participants with history of an index ankle sprain. After the follow-up periods of 12-187
13 months, 11 participants had re-sprained their ankles. Raw data from these two studies were pooled 188
and logistic regression was performed, finding that the predictive capacity of the model was not 189
statistically significant (Table 2). That is, CAIT score and number of foot lifts during single-leg stance 190
with eyes close did not predict re-sprain. 191
Severity of the index ankle sprain: Two studies investigated severity of the index sprain as a predictor 192
of CAI. Malliaropoulos23 et al used an expanded grading system26 (I, II, IIIA and IIIB) to determine 193
severity of sprain. They found significant differences in rate of re-sprain between athletes with 194
different grades of injury during a 24 month follow-up period. Elite track and field athletes with less 195
severe ankle sprain (grade I or II) had a higher rate of re-sprain than athletes with more severe ankle 196
sprain (grade IIIA or IIIB). To further analyse the results of this study, we performed direct logistic 197
regression to assess the impact of the severity of index sprain on the likelihood of re-sprain. The 198
predictive capacity of the model was statistically significant, X²(3, n=202) = 14.71, P=0.002. The 199
severity of sprain (grades I to IIIB) explained between 7% (Cox and Snell R2) and 11.4% (Nagelkerke 200
R2) of the variance in re-sprain status, and correctly classified 81.7% of cases. However, only grade I 201
and II made a unique statistically significant contribution to the model (Table 2). The strongest 202
predictor of re-sprain was grade II injury, recording an odds ratio (OR) of 2.6. This indicates that 203
athletes with grade II injury were 2.6 times more likely to re-sprain their ankles. 204
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In the second study, Endele22 et al divided 30 children with an acute ankle sprain into three groups 205
based on the severity of their clinical symptoms (I, II or III). Only children with grade II and III were 206
followed up for eight months. Endele22 et al reported no significant differences between children with 207
grades II or III of ankle sprain, with regard to limitation of mobility, pain or instability, three months 208
after the index injury. These outcome measures were not reported at eight months follow up. Due to 209
the small number of participants in this study (n=15) no further analysis was performed. 210
211
4. Discussion 212
213
The present systematic review found that only three potential predictors of CAI (severity of sprain, 214
balance and perceived instability) had been investigated in longitudinal studies after an index ankle 215
sprain. Although recent evidence from cross-sectional studies shows that postural sway, time to 216
balance after a jump, foot position during gait, strength, and proprioception are altered in participants 217
with CAI,14,15,19 none of these factors has been investigated in a longitudinal study after the index 218
sprain. 219
Two studies investigated the severity of the index ankle sprain as a potential predictor of CAI, with 220
conflicting results. Although there are factors limiting comparisons between these studies, including 221
the use of different grading systems, different age groups (adults23 vs. children22), and different 222
duration of follow-up (24 months23 vs. 8 months22), a critique of the two studies highlights some 223
critical issues. 224
Malliaropoulos23 et al, classified the severity of index sprains into four grades based on the patients’ 225
clinical symptoms (dorsiflexion range of motion and swelling). Participants were referred for stress 226
radiography only if they were diagnosed with a grade III sprain. In the second study, Endele22 et al 227
also classified the sprains as grades I, II or III based on the clinical symptoms (weight bearing status 228
and swelling), however, they performed additional MRI investigations. Interestingly, they found that 229
clinical symptoms were not well correlated with the grade of injury. The amount of swelling and 230
ability to weight bear were highly correlated with bone bruising, based on their MRI findings. 231
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Furthermore, six (50%) children with sprains classified as grade II based on the clinical symptoms, 232
had complete ligament rupture and three had a Salter I injury. These findings raise concerns about the 233
validity of the grading systems based on symptoms, alone. 234
The second study22 provides valuable information regarding the severity of ankle sprain in 30 235
children. In this study however, only children with sprains classified as grade II or III were followed 236
up, and the follow-up was at eight months, potentially an inadequate period when investigating re-237
sprain and CAI. In this study, anatomical changes were reported in the MRIs of 10 children at eight 238
months, but Endele 22 et al did not re-assess pain, mobility or instability at eight months follow up. 239
Since the main aim of this study was to compare symptoms with MRI findings, the outcomes of pain, 240
instability or mobility were not reported. 241
Based on the results of these two studies, it is not possible to conclude definitively that ankle sprains 242
classified as grades I or II predict development of CAI. To be able to determine whether the severity 243
of an initial sprain predicts CAI, a valid grading system, a large sample size and adequate follow-up 244
are required. 245
Pooled data from the two other studies24,25 showed that CAIT scores do not predict re-sprain. CAIT is 246
a measure of perceived instability27 and previous studies demonstrated that perceived ankle instability 247
is related to ankle sprain.28 However, based on the new model of sub-groups of CAI developed by 248
Hiller29 et al, there is a sub-group of participants with CAI who have perceived instability without 249
recurrence of sprain. The findings of Hiller25 et al and de Noronha24 et al support the proposed model, 250
and explain the lack of predictive value of the CAIT score. Decreased CAIT score, or presence of 251
perceived instability, may increase risk of re-sprain in some subgroups, but not others. 252
The results of this systematic review also show that postural control, measured as the number of foot 253
lifts during single-leg stance with eyes closed was not a predictor of CAI. Many studies have 254
investigated postural control as a predictor of acute ankle sprain.25,30,31 These studies however, used 255
different measurement methods and found different results. While most of these studies found 256
decreased postural control as a predictor of acute ankle sprains,25,32 several found no relationship 257
between postural control scores and the risk of ankle sprain.30,31,33 In a recent systematic review, 258
Witchalls34 et al reported that the studies in which postural control was tested by scoring the number 259
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of errors during a test, did not show that poorer postural control increased the risk of ankle sprain. 260
They suggested that the increased subjectivity of these methods may increase the variability in scores 261
and render them less meaningful for measuring postural control. 262
While it seems the number of foot lifts during single-leg stance might not predict re-sprain, these 263
results should be interpreted with caution. Firstly, the different populations in these two studies 264
(adolescent dancers25 vs. active university students24) may have been a confounding factor. In 265
addition, the time from the index ankle sprain was not controlled for, potentially constituting another 266
confounding factor. Finally, the aim of these studies was not to predict CAI after an index sprain, and 267
therefore data were a subset. This resulted in a small number of participants in these two studies with 268
consequent lack of power for our re-analysis. 269
The strength of this systematic review was that no language limitations were imposed. Where 270
required, a translation in different languages was made (e.g. German, Italian, Japanese, and French). 271
We also included the grey literature. However, several studies could not be included because 272
reporting was insufficient and the data were not available for further analysis. 273
274
5. Conclusion 275
276
We found that of the three potential predictors of CAI that have been investigated prospectively after 277
an index ankle sprain, only severity of initial sprain (grade II) predicted re-sprain. However, concerns 278
about validity of the grading system suggest that these findings should be interpreted with caution. 279
Consequently, there is a large gap in the literature. Anatomical, central, physiological and 280
psychosocial changes have yet to be investigated after an initial sprain and the relationship of such 281
variables to re-injury and other residual symptoms remains unknown. 282
283
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283
Practical Implications 284
285
• Severity of the initial ankle sprain does not necessarily predict the likelihood of 286
developing chronic ankle instability. 287
• Perceived ankle instability and static balance do not appear to predict future ankle 288
sprains. 289
• Currently there is limited research investigating predictors of chronic ankle instability after 290
an index ankle sprain. 291
292
Acknowledgment 293
294
The authors would like to thank Dr Markus Hübscher, Ms Naomi Kusano, and Ms Alexandra Di Lallo 295
for their assistance in translation of non-English papers. 296
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Tables 374
Table 1. Characteristics of included studies 375
CAIT: Cumberland ankle instability tool, ER: Emergency room, MRI: magnetic resonance imaging, Mths: months, S: seconds, Yr: year 376
*The method of measurement for pain, mobility and instability was not explained in the study377
Author, Year Type of Study
Follow-up length
Participants Inclusion/Exclusion criteria Predictor Interventions Outcome measures
Hiller et al 2008
Prospective Cohort
13 mths 33 adolescents dancers with an index sprain Age: 14 ± 1.8 yrs (total study participants: 115)
Inclusion: Dance and ballet students Exclusion criteria: None
Cumberland Ankle Instability tool, Foot movement during single-leg stance with eyes closed (30 s)
None Re-sprain
Malliaropoulos et al 2009
Prospective Cohort
24 mths
202 elite Greek track and field athletes Age: 19 ± 4.1 yrs
Inclusion criteria: Acute index lateral ankle sprain, no history of ankle and foot injury Exclusion criteria: syndesmotic injury or a lower limb fracture
Severity of the initial sprain (I, II, IIIA or IIIB)
Common rehabilitation program
Re-sprain
de Noronha et al 2011
Prospective Cohort
12 mths
11 active university students with an index sprain Age: 20.9 ± 2.7 yrs (total study participants: 125)
Inclusion criteria: regular exercise (≥2/week) Exclusion criteria: sprain ≤ 1 month
CAIT, Foot movement during single-leg stance with eyes closed (30 s)
None
Re-sprain
Endele et al 2012
Prospective Cohort
8 mths
30 children presenting to ER(15 followed up for 8 mths ) Age: 11.2 yrs (range: 7-15)
Inclusion criteria: Acute index inversion sprain (≤ 2 days) with open epiphyseal plate Exclusion criteria: fracture or recurrent sprains
Severity of the initial sprain (I,II, III)
Initially:elastic compression wraps, AirSport Ankle brace, forearm crutches (if required). After 2 weeks: common rehabilitation program
Pain, mobility and instability* MRI
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Table 2. Odds ratio of re-sprains associated with CAIT scores, balance, and severity of the initial sprain 378
Variables OR 95% CI for odds ratio P-value
CAIT scores and balance Step 1
CAIT score (injured side) CAIT score (non-injured side) Foot-lifts (injured side) Foot-lifts (non-injured side) Constant
0.839 1.037 0.958 1.017 15.887
0.664-1.061 0.800-1.346 0.897-1.057 0.914-1.132
0.142 0.782 0.391 0.756 0.403
Severity of the initial sprain Step 1 Grade I
Grade II Grade III Constant
2.603 0.364 0.162
1.175-5.768 0.065-1.466
0.004 0.018 0.139 < 0.01
OR: odds ratio, CI: confidence interval379
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380 Figure Legends 381
Figure 1: Flow chart of the review process 382
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Figure(s)