Interventions for preventing ankle ligament injuries
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the effects (benefits and harms) of interventions for preventing ankle ligament injuries and re‐injuries.
It is anticipated that the population will consist predominantly of individuals, from adolescence to middle age, who are participating in regular sports and other physical activities. Where possible, individuals undergoing rehabilitation for ankle sprains will be analysed separately.
The specific objectives of this review are to assess differences in outcomes between:
-
Any intervention aimed at the prevention of ankle ligament injuries versus no intervention;
-
Different interventions aimed at the prevention of ankle ligament injuries.
Background
Description of the condition
While people are encouraged to take part in sports and other physical activities because of their benefits to health (Haskell 2007), participation in such activities generally increases the risk of injury. The ankle joint is the most common location of injury for many physical activities (Fong 2007).
Most ankle injuries are acute sprains, involving injury to the ankle ligaments. The majority of ankle sprains involve the lateral ligaments; these are situated on the outer side of the ankle. In the United States, the incidence rates of ankle sprain range from 2.15 per 1000 person‐years in the general population (Waterman 2010a) to 58.4 per 1000 person‐years in physically active populations (Waterman 2010b). About half of all ankle sprains occur during athletic activity, with basketball, football, and soccer being associated with the highest number of ankle sprains (Waterman 2010a).
Injury to the lateral ligaments occurs as a result of a forced inversion (inward movement of the foot) while the foot is in plantar flexion (foot bent downwards) (Wexler 1998). In this vulnerable plantar flexed position, the bony stability in the ankle joint is minimal and stability is provided by the ligaments alone. Injury occurs to the anterior talofibular ligament first, followed to a varying degree by the calcaneofibular ligament. The posterior talofibular ligament is usually uninjured unless there is a frank dislocation of the ankle. Together, these ligaments form the lateral ligament complex.
Clinically, lateral ligament injuries are graded 1, 2 or 3. Grade 1 (mild) involves a stretch (or sprain), grade 2 (moderate) involves a partial tear, and grade 3 (severe) involves a complete tear (Kannus 1991). Most ankle sprains heal without residual complaints. However, up to one in three people re‐injure their ankle (Bahr 1997;Beynnon 2001;Verhagen 2004), which can result in disability and can lead to chronic pain or instability in up to 40% of re‐injured cases (Gerber 1998; Yeung 1994).
Description of the intervention
In an attempt to prevent (primary prevention) ankle sprains, ankle taping, braces, modified footwear and associated supports, adapted training regimens including ankle exercises, and injury awareness have been used (Handoll 2001). Secondary prevention (prevention of re‐injury or recurrence) includes interventions such as neuromuscular training aimed at enhancing coordination and retraining proprioception (sense of joint and muscular position). Neuromuscular training typically involves the use of 'wobble boards' (also called ankle disks). Neuromuscular training is also referred to as balance training, proprioceptive training, or sensorimotor training. Secondary prevention is a common treatment goal in the management of ankle sprains.
How the intervention might work
External measures for the ankle joint were originally designed with the aim of restricting abnormal range of ankle motion. Historically, it was presumed that the support system that provides the best mechanical stabilisation would be the best system to prevent ankle injuries. However, based on outcomes from clinical and mechanical studies it is more likely that external measures act primarily by supporting neuromuscular function rather than by restricting the range of ankle motion (Hupperets 2009; Verhagen 2000;Verhagen 2001).
Neuromuscular (i.e. sensorimotor, proprioceptive, balance) training is a well‐established secondary preventive measure. The rationale behind this intervention is that athletes who sustain an ankle sprain have a higher risk of re‐injury within one to two years of the injury (Bahr 1997;Ekstrand 1990;Verhagen 2004). Besides ligamentous weakness, impairment of proprioception after an ankle sprain is generally thought to be the cause of the increased injury risk (Freeman 1965). It is assumed that neuromuscular training improves this deficit by re‐establishing and strengthening the protective reflexes of the ankle (Karlsson 1993).
Why it is important to do this review
Ankle ligament injury is the most prevalent and universal sports injury. Prevention of ankle injuries could preserve health in people who participate in high‐risk sports and those who have suffered a previous ankle ligament injury. Since the publication in 2001 of the previous Cochrane review in this area (Handoll 2001), several more effectiveness studies have been conducted and published. More recently, two systematic reviews have been published specifically exploring the preventive effect of external ankle supports (Dizon 2010) and neuromuscular training (Hubscher 2010). However, neither review examines the effects of the various preventive measures against each other. Therefore, a new synthesis of available literature is warranted to establish the effectiveness of preventive measures for acute lateral ligament injury of the ankle.
Objectives
To assess the effects (benefits and harms) of interventions for preventing ankle ligament injuries and re‐injuries.
It is anticipated that the population will consist predominantly of individuals, from adolescence to middle age, who are participating in regular sports and other physical activities. Where possible, individuals undergoing rehabilitation for ankle sprains will be analysed separately.
The specific objectives of this review are to assess differences in outcomes between:
-
Any intervention aimed at the prevention of ankle ligament injuries versus no intervention;
-
Different interventions aimed at the prevention of ankle ligament injuries.
Methods
Criteria for considering studies for this review
Types of studies
Randomised and quasi‐randomised (method of allocating participants to a treatment which is not strictly random; e.g. by date of birth, hospital record number or alternation) controlled trials evaluating interventions for preventing ankle ligament injuries will be considered for inclusion.
Types of participants
Individuals at risk of, or who have had a previous, ankle ligament injury will be eligible. We expect that the majority of trial populations will fall into the adolescence to middle age category, which reflects the greater participation in high‐risk activities for ankle sprains. This review will also include people who have undergone rehabilitation after an ankle sprain.
Types of interventions
Any intervention, including use of (modified) footwear, external ankle supports, ankle taping, adapted training programmes including ankle exercises, co‐ordination and/or neuromuscular training programmes, and injury awareness, which were applied to prevent ankle ligament injury, will be eligible. Trials involving testing of preventative devices in laboratory conditions or which only report intermediate outcome measures that have no proven relationship to clinical outcomes will be excluded.
Trials involving the rehabilitative treatment of ankle sprains will be included, providing the interventions under study were specifically intended to reduce the risk of re‐injury, and that re‐injury data were actively collected and reported.
Types of outcome measures
The reporting of ankle ligament injury is a criterion for study inclusion.
Primary outcomes
-
Incidence of ankle ligament injury;
-
Severity of ligament injuries to the ankle (grade, surgery considered); and
-
Patient‐assessed ankle function (e.g. giving way, performance inhibition).
Secondary outcomes
-
Incidence of other lower extremity injuries;
-
Complications (e.g. fitness deficit, skin abrasions, other injuries);
-
Measures of service utilisation or resource use (e.g. practitioner visits, costs of intervention); and
-
Compliance (adherence) to the intervention.
Search methods for identification of studies
Electronic searches
We will search the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (to present), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, current issue), MEDLINE (1948 to present), EMBASE (1980 to present), SPORTDiscus (1985 to present), and CINAHL (1937 to present). We will also search the WHO International Clinical Trials Registry Platform for ongoing and recently completed trials. No language restriction will be applied.
In MEDLINE, the subject specific strategy will be combined with the sensitivity‐ and precision‐maximizing version of the Cochrane Highly Sensitive Search Strategy for identifying randomised trials (Lefebvre 2011). In EMBASE, the subject‐specific strategy will be combined with the RCT search filter developed by the Scottish Intercollegiate Network. Search strategies for CENTRAL, MEDLINE, EMBASE, SPORTDiscus, CINAHL, and the WHO International Clinical Trials Registry Platform can be found in Appendix 1.
Searching other resources
We will check the reference lists of relevant studies and reviews.
Data collection and analysis
Selection of studies
Initial study selection will be performed independently by two review authors (KWJ and EV). Both authors will examine titles and abstracts to produce a list of potentially relevant reports. Full texts will then be retrieved and examined independently by the same review authors in order to obtain a final list of eligible reports. If consensus cannot be achieved, a third party (PvdW) will adjudicate. Where necessary, we will contact trial authors for clarification and additional information to inform study selection.
Data extraction and management
Key information from each included study will be independently extracted by two review authors (KWJ and EV) using a piloted data collection form. This form will collect information on the source, study eligibility, study design and methods, study participants, interventions used, outcome measures, and results. The trial authors will be contacted where the reports do not provide full information. Where necessary, consensus will be reached by discussion.
Assessment of risk of bias in included studies
Risk of bias of all included studies will be independently assessed by two review authors (KWJ and EV) using The Cochrane Collaboration's 'Risk of bias' tool (Higgins 2011; seeAppendix 2). This tool assesses selection bias (random sequence generation and allocation concealment), performance bias (blinding of participants and personnel), detection bias (blinding of outcome assessment), attrition bias (incomplete outcome data), reporting bias (selective reporting), and other sources of bias. The latter include bias from major imbalances in baseline characteristics, performance bias (from systematic differences in the care provided) and sponsorship bias (from funding sources). Where necessary, a third review author (PvdW) will adjudicate on differences of opinion. We will consider subjective and objective outcomes separately in our assessment of assessor blinding, and short‐term and longer‐term outcomes for completeness of outcome data.
Measures of treatment effect
We will calculate risk ratios with 95% confidence intervals for dichotomous data and mean differences, or standardised mean differences where different scales are used, with 95% confidence intervals for continuous data. Where appropriate data are available, we will also calculate the numbers needed to treat to avoid one additional ankle sprain.
Unit of analysis issues
Cluster randomisation may be used in some trials eligible for inclusion. When allocation is by a group of participants, such as a platoon or soccer team, unit of analysis errors are likely to result from the presentation of outcome by the individual participants. The risk of injury of such individuals cannot be considered independently of the cluster unit (platoon/team). Using statistical methods which assume, for example, that all participants’ chances of injury are independent ignores the possible similarity between outcomes for participants within the same platoon or team. This may underestimate standard errors and give misleadingly narrow confidence intervals, leading to the possibility of spurious positive findings (Bland 1997). Whilst we will present the overall results of these trials where available and will use adjusted data if feasible, we will indicate these as cluster randomised trials and suggest cautious interpretation.
Dealing with missing data
Where necessary, we will contact trial authors for missing data, including intra‐class correlation coefficients for cluster randomised trials.
Assessment of heterogeneity
Heterogeneity of the included studies will be assessed by visual inspection of the analyses, along with consideration of the chi² test for heterogeneity and the I² statistic.
Assessment of reporting biases
Possible duplicate publications of the same studies will be addressed by taking into account the following from each identified study: author names, study design, presented sample demographics, location and setting of the intervention. Where uncertainties remain after these factors are considered, we will correspond with the study authors. Funnel plots will be used to assess reporting bias when there are 10 or more trials in a comparison.
Data synthesis
Where appropriate, the results of comparable studies will be pooled using the fixed‐effect model. The individual and pooled statistics will be reported as either risk ratios, mean differences or standardised mean differences; all with 95% confidence intervals.
Subgroup analysis and investigation of heterogeneity
Where possible, we intend to subgroup data by history of previous sprain and gender. We will investigate whether the results of subgroups are significantly different by inspecting the overlap of confidence intervals, and performing the test for subgroup differences and the I² statistic available in RevMan.
Sensitivity analysis
Where possible, we will conduct sensitivity analyses to evaluate the effects of various aspects of trial and review methodology, including the effect of missing data, inclusion of trials at high risk of bias, principally from lack of allocation concealment, or for which only abstracts were obtained.
'Summary of findings' tables
Where there is sufficient evidence to merit the preparation of 'Summary of findings' tables, we will develop these for each of the main comparisons. We will use the GRADE approach to assess the quality of evidence related to each of the key outcomes listed in the Types of outcome measures (Chapter 12.2, Higgins 2011).
