Description of the condition
The Achilles tendon is the thickest and strongest tendon in the human body. It attaches the powerful calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus). Rupture of the Achilles tendon is one of the most common tendon injuries in the adult population, with an estimated mean annual incidence ranging from 5.5 to 9.9 ruptures per 100,000 people in Canada (Suchak 2005), and values in Europe ranging from 6 ruptures per 100,000 people in Scotland (Maffulli 1999a) to 18 ruptures per 100,000 people in Finland (Leppilahti 1996). Most acute ruptures occur in people in their thirties or forties during sports activities; however, a smaller peak incidence in older non-athletic people should not be overlooked (Maffulli 1999a). The incidence of this injury is increasing, possibly as a result of the continuing participation in recreational sports activities in later life by the ageing population (Jozsa 1989; Nandra 2012).
The aetiology of spontaneous rupture of the Achilles tendon is not yet fully understood. It is generally considered that primary abnormalities have been present before the ruptures occur (Arner 1959; Maffulli 2000). Multiple causative factors such as tendon degeneration and collagen alteration (Jarvinen 1997), a reduction in blood supply to the midportion of the tendon (Ahmed 1998), conditions comorbid with systemic diseases (Leppilahti 1998), previous administration of steroids or fluoroquinolone antibiotics (Maffulli 1999b; Tsai 2011) and exercise-induced hyperthermia (Wilson 1994) may predispose the Achilles tendon to spontaneous rupture from microtrauma.
Acute Achilles tendon rupture is a debilitating injury, often resulting in prolonged disability and rehabilitation (Willits 2010). Providing patients with a prompt and accurate diagnosis and appropriate treatment is essential to avoid permanent disability and loss of function. A detailed history and physical examination (presence of a palpable gap, decreased ankle plantar flexion strength, and positive Thompson test or other physical tests) is generally sufficient for establishing a clinical diagnosis of acute Achilles tendon rupture (Maffulli 1998). In addition, ultrasonography and magnetic resonance imaging (MRI) can be helpful in some cases (Nandra 2012).
Description of the intervention
Primary treatment of acute Achilles tendon ruptures can be either conservative, generally involving full or partial immobilisation of the ankle, or surgical, generally involving the operative repair of the ruptured tendon. Although surgery tends to have a lower risk of re-rupture compared with non-surgical (conservative) treatment, the risk of infection and other complications are significantly higher (Bhandari 2002; Khan 2010; Lo 1997; Lynch 2004). Currently, conservative treatment is an option for all patients, including those declining surgery, and those for whom an operation or anaesthesia is contraindicated because of impaired healing potential (Maffulli 1999b; Willits 2010). Traditionally, conservatively treated patients usually wear a below-knee cast in equinus for four weeks without weight-bearing, followed by a second cast with the foot in neutral position allowing weight-bearing for another four weeks (Cetti 1993). Differences may exist in terms of the casting materials and techniques used (e.g. use of a heel raise), the duration of immobilisation, the duration of non-weight-bearing and the rehabilitation protocol. More recently, a combination of cast immobilisation and functional bracing (which allows immediate weight-bearing and active plantar flexion but restricts dorsiflexion of the ankle (McComis 1997)), or immediate functional bracing alone, have been introduced to minimise the complications associated with a long period of immobilisation, such as joint stiffness and muscle atrophy (Khan 2010; McComis 1997; Saleh 1992).
Similarly, conservative management after surgical repair of the ruptured Achilles tendon usually entails full or partial immobilisation. The postoperative rehabilitation protocol after surgery has evolved from using rigid immobilisation in a below-knee cast without weight-bearing for four to nine weeks (Cetti 1994) to an early functional protocol involving immediate mobilisation with early weight-bearing using functional bracing (a walking boot or modified orthosis) instead of a cast (Costa 2006; Kangas 2003; Suchak 2008). Physiotherapy for people with acute rupture of the Achilles tendon currently comprises a combination of different individual components of a specific rehabilitation regimen involving the type of cast or orthosis used, the degree of plantar flexion of the ankle, the timing of removal of the orthosis and the implementation of daily range of motion exercises, which have all been identified as variables to be evaluated in further research (Kearney 2012).
How the intervention might work
Conservative treatment, which initially immobilises the patient in a below-knee cast with non-weight-bearing in equinus, can reduce iatrogenic damage to normal tissue and protect the blood supply to the injured tendon, thus facilitating healing. However, prolonged immobilisation in a plaster cast may lead to a series of complications including joint stiffness, calf muscle atrophy, tendocutaneous adhesion and deep venous thrombosis (Mortensen 1999; Saleh 1992). Casting, which has also been the standard postoperative regimen after repair of a ruptured Achilles tendon, can make rehabilitation after surgery more difficult (Kangas 2003). With the merits of avoiding the risks of immobilisation, reducing rehabilitation time, and facilitating an early return to work and sporting activity, functional bracing has been promoted as a viable alternative to the use of a plaster cast (McComis 1997). Experimental studies have demonstrated that early loading of the ruptured tendon leads to benefits in improved tendon characteristics and decreased muscle atrophy (Kjaer 2005; Rantanen 1999). Additionally, some comparative clinical studies have suggested that appropriately implemented functional bracing combined with a rehabilitation protocol that allows early mobilisation and weight-bearing gives comparable results in terms of re-rupture and functional outcomes to those found for surgical repair (Costa 2006; Metz 2008; Twaddle 2007); however, concerns still remain about increased discomfort and pain while the patient walks, and an increased re-rupture rate from damage to the healing tendon caused by early loading of the tendon (Khan 2010; Suchak 2008).
Why it is important to do this review
There is no consensus regarding either the optimal primary conservative management of acute Achilles tendon ruptures or optimal management after surgery. Traditionally, plaster cast with prolonged immobilisation has been the standard treatment in both situations. However, the need for prolonged rigid immobilisation has been questioned, especially as satisfactory results have been reported for early mobilisation involving functional bracing. This points to the need to systematically appraise the current evidence of the effects and harms of different conservative interventions for treating acute Achilles tendon ruptures.
To assess the effects (benefits and harms) of different conservative interventions for the primary or postsurgical management of acute Achilles tendon ruptures.
The main focus will be on comparisons of different types and durations of splintage. Findings for primary and postsurgical management will be presented separately.
Criteria for considering studies for this review
Types of studies
We will include randomised controlled trials (RCTs) and quasi-RCTs (in which methods of allocating participants to a treatment, e.g. by date of birth, hospital record number, date of admission, alternation, are not strictly random) evaluating conservative interventions for treating acute Achilles tendon ruptures.
Types of participants
People of all ages (including children and adolescents) with acute Achilles tendon ruptures. Studies specifically focusing on people with delayed presentation (more than three weeks postinjury) or with recent re-ruptures will be excluded. Mixed population studies, which include such participants or those with other ankle injuries, will be included, provided separate data are available for participants with acute primary rupture of the Achilles tendon, or the proportion of participants with other injuries is small and balanced between treatment groups.
Types of interventions
All forms of conservative interventions, including cast immobilisation, functional bracing or a combination of these. The main comparison will be immediate functional bracing or a combination of casting with functional bracing versus casting alone. Additionally, we will compare early versus late mobilisation. More detailed components of the rehabilitation protocol, such as different types of exercises, are beyond the scope of the current review. Typically, the control group of a comparison will be the intervention involving the greater degree of immobilisation. Conservative interventions for primary and postoperative management will be analysed separately.
Types of outcome measures
- Re-rupture rate
- Rates of complications (e.g. adhesions, nerve damage, deep vein thrombosis) other than re-rupture
- Proportion of individuals returning to work and sport, and time to return to work and sport, including assessments of attainment of same level of sporting activity
- Cosmetic issues such as differences in calf circumference between injured and non-injured leg
- Long-term pain
- Strength measurement of ankle plantar flexion and dorsiflexion
- Range of motion of the ankle joint
We will also collect data on resource use (e.g. length of hospital stay, costs).
Search methods for identification of studies
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) and EMBASE (1980 to present).
In MEDLINE (Ovid online), the subject-specific search will be combined with the sensitivity-maximising version of the Cochrane Highly Sensitive Search Strategy for identifying randomised trials (Lefebvre 2011) (see Appendix 1). Search strategies for CENTRAL and EMBASE are also shown in Appendix 1.
We will search Current Controlled Trials and the WHO International Clinical Trials Registry Platform for ongoing and unpublished trials. No language or publication restrictions will be applied.
Searching other resources
We will search the reference lists of articles to identify additional trials. The bibliographies of recently published review articles will also be checked for potentially relevant citations. When additional clarification is required, we will contact the authors of identified studies.
Data collection and analysis
Selection of studies
Two review authors (CS and QZ) will independently screen the search results for potentially eligible trials. After obtaining full text articles, both authors will independently select studies for inclusion. In case of disagreement, a third review author (YW) will be consulted and a decision will be made through discussion.
Data extraction and management
Two review authors (CS and QZ) will independently extract data on trial design, study population, interventions and the outcomes listed above using a data extraction form specifically designed for this review. We will resolve any differences by referring back to the original article and reaching a consensus. When necessary and practical, we will contact the trial authors for additional information.
Assessment of risk of bias in included studies
Two review authors (CS and QZ) will assess the risk of bias independently using the domain-based evaluation tool recommended by The Cochrane Collaboration (Higgins 2011). Any differences will be resolved by discussion. If disagreement still exists, we will consult a third author (YW) to act as an arbitrator. We will assess the following domains.
- Random sequence generation (assessment of selection bias)
- Allocation concealment (assessment of selection bias)
- Blinding of participants and personnel (assessment of performance bias)
- Blinding of outcome assessment (assessment of detection bias)
- Incomplete outcome data (assessment of attrition bias)
- Selective reporting bias
- Other potential sources of bias such as major imbalances in key baseline characteristics
Measures of treatment effect
We will use risk ratios (RR) with 95% confidence intervals (CI) for reporting dichotomous data. We will use mean differences (MD) with 95% CI for continuous outcomes. We will use standardised mean differences (SMD) with 95% CI where continuous data from different scales or scoring systems are pooled.
Where appropriate and where the RR (a relative measure) is statistically significant, we will calculate the risk difference (RD) and convert this into the number needed to treat for an additional beneficial outcome (NNTB) or number needed to treat for an additional harmful outcome (NNTH).
Unit of analysis issues
We anticipate that the unit of randomisation in the included trials will be the individual person. Very occasionally, when participants are included who have sustained bilateral injuries, results may be presented for tendons or limbs. Where such unit of analysis issues arise and appropriate corrections have not been made, we will consider presenting the data for those trials in which the disparity between the units of analysis and randomisation is small. Where data are pooled, we will perform a sensitivity analysis to examine the effects of excluding incorrectly reported trials from the analysis. We will be alert to other potential unit of analysis issues, such as those relating to multiple observations for the same outcome.
Dealing with missing data
When necessary, we will seek to add insufficient data or obtain missing data by contacting the authors of the primary studies. We will perform intention-to-treat (ITT) analyses to include all trial participants wherever possible. Unless missing standard deviations can be derived from CIs, P values or standard errors, we will not assume values in order to present these in the analyses.
Assessment of heterogeneity
We will assess heterogeneity between comparable trials by visually examining the forest plot and using the Chi² test with significance set at a P value of < 0.1. The I² statistic (Higgins 2003) will be used to quantify inconsistency across studies and assess its impact on the meta-analysis, where values of 0% to 40% might not be important, 30% to 60% may represent moderate heterogeneity, 50% to 75% may represent substantial heterogeneity and 75% to 100%, considerable heterogeneity (Higgins 2011).
Assessment of reporting biases
When data can be pooled from 10 or more trials, we will assess potential publication biases using funnel plots (Egger 1997).
When considered appropriate, we will pool the results of comparable groups of trials using both fixed-effect and random-effects models. The choice of the model to be reported will be guided by a careful consideration of the extent of heterogeneity and whether it can be explained, in addition to other factors such as the number and size of studies that are included. We will use 95% CIs throughout. We will consider not pooling data where there is considerable heterogeneity (I² > 75%) that cannot be explained by the diversity of methodological or clinical features among the trials. Should meta-analysis not be possible or appropriate, we will report the data from these trials individually and, where available, present data in forest plots without totals.
Subgroup analysis and investigation of heterogeneity
We will perform subgroup analyses to investigate heterogeneity of effects, which may be conducted based on:
- age groups: children (< 18 years old) versus adults (18 to 65 years old) versus older adults (> 65 years old);
- participants' levels of sports activity: professional and competitive athletes versus recreational or non-athletes;
- different surgical techniques for postoperative comparisons: open versus minimally invasive/percutaneous surgery.
We will investigate whether the results of subgroups are significantly different by inspecting the overlap of CIs and performing the test for subgroup differences available in Review Manager 5.2 software (RevMan 2012).
We plan to perform sensitivity analyses in order to explore the effects of various aspects of trial and review methodology, by repeating the analysis and including only studies published in full reports with adequate allocation concealment, blinded outcome assessors or at least 80% follow up of participants in each group, and using different measures of calculating treatment effects (e.g. RD, odds ratio) and different statistical models (fixed-effect and random-effects models).
'Summary of findings' tables
Where there are sufficient data, the main results of this review will be presented in 'Summary of findings' tables. We shall use the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to assess the quality of evidence related to each of the primary outcomes listed in the Types of outcome measures (Section 12.2, Higgins 2011). The GRADE approach considers risk of bias, directness of evidence, heterogeneity, precision of effect estimates and risk of publication bias.
We wish to thank Laura CI MacDonald and Lindsey Elstub for their kind help during the development of this protocol and Joanne Elliott for helping develop the search strategies. We are grateful to Keith Hill, Helen Handoll and Judith Tarazona for their helpful feedback as editors and external referee.
This project was supported by grants from the National Natural Science Foundation of China (No. 81201404).
Appendix 1. Search strategies
The Cochrane Central Register of Controlled Trials (Wiley Online Library)
#1 MeSH descriptor: [Achilles Tendon] this term only
#2 (achill?s or tendoachill?s or ((calcane* or heel*) near/1 tendo*)):ti,ab,kw (Word variations have been searched)
#3 #1 or #2
#4 MeSH descriptor: [Rupture] this term only
#5 (rupture* or tear* or repair* or injur*):ti,ab,kw (Word variations have been searched)
#6 #4 or #5
#7 #3 and #6
MEDLINE (Ovid Online)
1 Achilles Tendon/
2 (achill#s or tendoachill#s or ((calcane* or heel*) adj1 tendo*)).tw.
5 (rupture* or tear* or repair* or injur*).tw.
8 Randomized Controlled Trial.pt.
9 Controlled Clinical Trial.pt.
12 Drug Therapy.fs.
17 exp Animals/ not Humans/
18 16 not 17
EMBASE (Ovid Online)
1 Achilles Tendon Rupture/
2 Achilles Tendon/
3 (achill#s or tendoachill#s or ((calcane* or heel*) adj1 tendo*)).tw.
5 Rupture/ or Tendon Rupture/
6 (rupture* or tear* or repair* or injur*).tw.
10 Randomized Controlled Trial/
11 Clinical Trial/
12 Controlled Clinical Trial/
14 Single Blind Procedure/
15 Double Blind Procedure/
16 Crossover Procedure/
18 Prospective Study/
19 ((clinical or controlled or comparative or placebo or prospective* or randomi#ed) adj3 (trial or study)).tw.
20 (random* adj7 (allocat* or allot* or assign* or basis* or divid* or order*)).tw.
21 ((singl* or doubl* or trebl* or tripl*) adj7 (blind* or mask*)).tw.
22 (cross?over* or (cross adj1 over*)).tw.
23 ((allocat* or allot* or assign* or divid*) adj3 (condition* or experiment* or intervention* or treatment* or therap* or control* or group*)).tw.
26 Case Study/ or Abstract Report/ or Letter/
27 25 not 26
Contributions of authors
Cheng Sun, Qi Zhuo, Wei Chai, Jiying Chen, Wei Yang and Peifu Tang contributed equally to the protocol. Yan Wang is the guarantor of the review.
Declarations of interest
Cheng Sun: none known
Qi Zhuo: none known
Wei Chai: none known
Jiying Chen: none known
Wei Yang: none known
Peifu Tang: none known
Yan Wang: none known
Sources of support
- Chinese PLA General Hospital/Medical School, China.
- Peking University Third Hospital, China.
- National Natural Science Foundation of China, China.