Surgical versus conservative interventions for treating acromioclavicular dislocation of the shoulder in adults
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the relative effects of surgical versus conservative (non‐surgical) interventions for treating acromioclavicular dislocations in adults.
Outcome will be measured primarily in terms of function, pain and serious adverse effects of treatment.
Background
Description of the condition
The acromioclavicular joint is located at the top of the shoulder. It is the joint between the acromion (a process at the top of the spine of the scapula or shoulder blade) and the lateral (outer) end of the clavicle (collarbone). The joint is stabilized by a combination of dynamic muscular (the deltoid and trapezius muscles) and static ligamentous (tough fibrous) structures: these are the acromioclavicular ligaments, which are located in the joint capsule and the coracoclavicular ligaments, connecting another process (the coracoid) at the top of the scapula and the clavicle (Post 1985).
The acromioclavicular dislocation is one of the most common problems in the general orthopaedic practice. It is the most prevalent shoulder injury in participants of contact sports (any sport in which the impact of one person against another is an inherent part of the sport, such as boxing, football, ice hockey and martial arts) (Bishop 2006). Data reveal that acromioclavicular dislocations occur in 41% of the collegiate football players and in 40% of the (US) National Football League quarterbacks (Kaplan 2005; Kelly 2004). These dislocations are more common in men than in women (ratio 5:1) (Jacobs 1966); perhaps because they are more likely to be practicing contact sports than women. This injury is more often an incomplete than a complete lesion (2:1) (Galatz 2005).
The most common mechanism of injury is a direct blow to the point of the shoulder, usually from a fall. Less commonly, an indirect trauma may be transmitted up the arm as a result of a fall onto an outstretched hand.
The clinical features of acute acromioclavicular dislocations include pain at the acromioclavicular joint, which does not usually radiate and its severity is often related to the degree of injury. The arm is voluntarily held by the side of the body and all movements are restricted because of pain. Physical examination may show swelling and bruising, an abrasion or a typical deformity described as the prominent clavicle and the depression below it (Bowers 1935).
Acromioclavicular separations have been described as subluxations when they are partial; and dislocations when complete (Imatani 1975). Allman 1967 has classified sprains of acromioclavicular joint into grades I, II and III:
-
Grade I: results from to a mild force that causes tearing of only a few fibres of the acromioclavicular ligament and capsule. There is no instability of the joint.
-
Grade II: is caused by moderate force with rupture of the capsule and acromioclavicular ligament. This injury often causes a subluxation (partial or incomplete dislocation). The coracoclavicular ligaments are not ruptured.
-
Grade III: results from a severe force that ruptures both the acromioclavicular and coracoclavicular ligaments, producing dislocation of the acromioclavicular joint.
This classification has been widely accepted (Taft 1987). Rockwood (Galatz 2005) identified six types of injury, the first three of which are the same as Allman's grades. The other three types (IV, V, and VI) are all Allman's Grade‐III injuries, varying only in the degree and direction of the clavicle displacement (seeTable 1).
| Type | Description |
| Type I | A mild injury involving spraining the acromioclavicular ligaments while leaving the joint intact. |
| Type II | Injury where the acromioclavicular ligaments are torn and acromioclavicular joint is disrupted, while the coracoclavicular ligaments are intact. |
| Type III | Injury involves complete tearing of both the acromioclavicular and coracoclavicular ligaments with 100% dislocation of the joint. |
| Type IV | Injury is a complete acromioclavicular dislocation with posterior displacement of the clavicle through or into the trapezius fascia |
| Type V | Injury is a complete acromioclavicular dislocation with 100% to 300% superior dislocation of the clavicle. It can involve significant disruption of the deltotrapezial fascia. |
| Type VI | Injury involves inferior displacement of the clavicle into a subacromial or subcoracoid position. |
Description of the intervention
Non‐surgical or conservative treatment generally involves immobilisation of the arm with a sling. Among other methods are braces and adhesive strapping. After a short period of immobilisation, lasting around two weeks, gradual mobilisation is started.
Surgical procedures include repositioning of the joint parts and the repair or reconstruction, or a combination of these, of the various ruptured ligaments using different devices such as the coracoclavicular screw and hook plate. Newer surgical interventions now exist which are currently being adopted but they have not been tested in randomised clinical trials so far. After surgery, the arm is immobilised in a sling to allow healing to take place.
How the intervention might work
Grade I and II injuries or acromioclavicular joint subluxations are almost invariably treated conservatively. This review focuses on the more severe injuries, where the joint is dislocated.
Surgical management for acromioclavicular dislocation has been advocated as it enables the restoration of the joint anatomy, thus avoiding the obvious deformity and a potentially unsatisfactory outcome (Rawes 1996). However, disadvantages of surgery include migration of pins used for fixation, erosion of the bone by fixation devices, failure of metallic fixation devices, recurrence of deformity, painful or unsightly scar, late development of acromioclavicular arthralgia and the necessity of a second operation to remove fixation devices (Weaver 1972).
The advantages of the conservative treatment are shorter period of rehabilitation and avoidance of hospitalisation (Bannister 1989; Larsen 1986; Rawes 1996). Reported disadvantages are that about 20% of patients treated conservatively have unsatisfactory results due to pain, instability and limitation of motion (Kennedy 1954). Moreover, there is an uncertainty regarding healing and the potential need for reconstructive surgery, which is more difficult to perform if the displacement has persisted for a long period (Larsen 1986; Roper 1982).
Why it is important to do this review
Over 35 conservative methods and nearly 30 surgical methods of correction have been identified and advocated for acromioclavicular dislocation. The question of whether surgery should be used remains controversial (Eskola 1987; Lancaster 1987; Phillips 1998; Press 1997; Spencer 2007).
We have identified two systematic reviews focussing on these injuries (Phillips 1998; Spencer 2007). Both reviews, which also included evidence from studies other than from randomised controlled trials, provisionally concluded against the use of surgery for the majority of dislocations but also emphasized the poor evidence base. Our review will test this basic treatment question by applying more rigorous methodology, including restricting the included studies to randomised or quasi‐randomised trials and performing a broader literature search that includes non‐English literature, and through enabling future updates in the light of new evidence.
Objectives
To assess the relative effects of surgical versus conservative (non‐surgical) interventions for treating acromioclavicular dislocations in adults.
Outcome will be measured primarily in terms of function, pain and serious adverse effects of treatment.
Methods
Criteria for considering studies for this review
Types of studies
Any randomised controlled trials and quasi‐randomised trials (that is those in which the allocation is not strictly random: e.g., by date of birth, hospital record number, alternation) comparing surgical with conservative interventions of acromioclavicular dislocation.
Types of participants
Included in this review will be trials with participants meeting the following criteria:
-
Skeletally mature (adults greater than 18 years of age);
-
History of acute (less than three weeks) acromioclavicular dislocation, irrespective of diagnosis method (usually clinical and image evaluations);
-
No other symptomatic shoulder disorders (e.g. osteoarthritis, shoulder instability, fracture).
Mixed population trials that include patients with acromioclavicular separations who do not meet these criteria will be included if the proportion of such patients is small (under 10%) or if separate data can be obtained for those meeting the above criteria.
Types of interventions
All surgical and conservative interventions used for treating acromioclavicular dislocation will be considered.
-
Surgical interventions include the coracoclavicular screw, reconstruction of coracoclavicular ligaments, acromioclavicular wires and hook plates;
-
Conservative interventions include immobilisation of the arm in a sling, use of braces and adhesive strapping.
Types of outcome measures
Primary outcomes
-
Health‐related quality of life;
-
Pain;
-
Return to previous occupation, including work, sport and activities of daily living;
-
Treatment failure and other serious adverse effects of treatment such as requirement for a subsequent operation.
-
Patient‐reported shoulder function.
Examples of commonly used instruments for measuring pain and function outcomes are:
-
VAS (visual analogue scale);
-
The Constant Score (Constant 1987);
-
Short Form‐36 (SF‐36) (Ware 1992);
-
Disability of the Arm, Shoulder, and Hand questionnaire ‐ DASH (Hudak 1996).
Secondary outcomes
Clinical outcomes
-
Shoulder range of motion;
-
Strength;
-
Cosmetic appearance;
-
Patient satisfaction with treatment.
Radiological outcomes
-
Residual deformity (distance between coracoid and clavicle or acromion and clavicle).
Resource use
-
Hospital admission and length of stay, number of outpatient attendances and other costs with treatment;
-
Time off work or education.
Safety: (success or failure of treatment and adverse events)
-
Complications:
‐ Early (e.g. wound or skin breakdown or skin necrosis under strapping, fixation failure, migration of wires, residual deformity, infection, reoperation);
‐ Late (e.g. traumatic arthritis, calcification of coracoclavicular ligament, reoperation).
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 (The Cochrane Library current issue), MEDLINE (1966 to present), EMBASE (1988 to present), and LILACS (1982 to present). We will also search Current Controlled Trials at www.controlled‐trials.com, the UK National Research Register (records up to September 2007 can be accessed at https://portal.nihr.ac.uk/Pages/NRRArchive.aspx) and the WHO International Clinical Trials Registry at www.who.int/ictrp/en/ for ongoing and recently completed trials. There will be no restrictions based on language or publication status.
In MEDLINE (PubMed) the Cochrane Highly Sensitive Search Strategy for identifying randomised trials, sensitivity‐ and precision‐maximizing version (Lefebvre 2008), will be combined with the subject specific search (Appendix 1). Search strategies are also shown for The Cochrane Library (Wiley InterScience; seeAppendix 2), EMBASE (Elsevier; seeAppendix 3), and LILACS (http://bases.bireme.br; seeAppendix 4).
Searching other resources
We will check reference lists of articles, reviews and textbooks for possible relevant studies. We will include the findings from handsearches of abstracts of the British Elbow and Shoulder Society annual meetings (2001 to present: www.bess.org.uk/meetings/archive.asp), the American Orthopaedic Trauma Association annual meetings (1996 to present: www.hwbf.org/ota/am/), and the American Academy of Orthopaedic Surgeons annual meetings (www.aaos.org/).
Data collection and analysis
Selection of studies
Two authors (MT and ML) will independently select and assess potentially eligible studies, using a piloted form, for inclusion in the review. Any disagreements will be resolved by discussion and, if necessary, adjudication by a third author (JB).
Data extraction and management
Two review authors (MT and ML) will use a piloted data extraction form to independently collect the data. Any disagreements will be resolved by a third review author (JB). Two review authors (MT and ML) will enter data into RevMan. Where necessary, we will send requests to trial authors for additional information or data.
Assessment of risk of bias in included studies
Two review authors (MT and ML) will independently assess various aspects of methodological quality of the included studies, using a modified version of the Cochrane Bone, Joint and Muscle Trauma Group's former quality assessment tool (seeTable 2). Data will also be collected for future inclusion in the Risk of Bias tables. Disagreement will be resolved by a third review author (MM).
| Items | Scores | Notes |
| (1) Was the assigned treatment adequately concealed prior to allocation? | Yes = method did not allow disclosure of assignment. | Cochrane code (see Handbook): Clearly yes = A; Not sure = B; Clearly no = C. |
| (2) Were the outcomes of participants who withdrew described and included in the analysis (intention‐to‐treat)? | Yes = withdrawals well described and accounted for in analysis. | |
| (3) Were the outcome assessors blinded to treatment status? | Yes = effective action taken to blind assessors. | |
| (4) Were important baseline characteristics reported and comparable? | Yes = good comparability of groups, or confounding adjusted for in analysis. | Although many characteristics including hand dominance are important, the principal confounders are considered to be age, gender, type of lesion (dislocation or subluxation). |
| (5) Were the trial participants blind to assignment status after allocation? | Yes = effective action taken to blind participants. | |
| (6) Were the treatment providers blind to assignment status? | Yes = effective action taken to blind treatment providers. | |
| (7) Were care programmes, other than the trial options, identical? | Yes = care programmes clearly identical. | Examples of clinically important differences in other interventions are: time of intervention, duration of intervention, difference in rehabilitation. |
| (8) Were the inclusion and exclusion criteria for entry clearly defined? | Yes = clearly defined (including type of fracture). | |
| (9) Were the outcome measures used clearly defined? | Yes = clearly defined. | |
| (10) Were the accuracy and precision, with consideration of observer variation, of the outcome measures adequate; and were these clinically useful and did they include active follow up? | Yes = optimal. | |
| (11) Was the timing (e.g. duration of surveillance) clinically appropriate? | Yes = optimal (> 1 year) |
Measures of treatment effect
Risk ratios with 95% confidence intervals will be calculated for dichotomous outcomes. Where appropriate, we will express estimate effects as NNTs (numbers needed to treat). The NNT corresponds mathematically to the inverse of risk difference and clinically to the number of patients to be treated to avoid one undesired event and will be calculated using the pooled risk ratio.
Continuous outcome data will be expressed as mean differences with 95% confidence intervals. When two or more studies present their data derived from the same instrument of evaluation (with the same units of measurement), data will be pooled as a mean difference (MD). Conversely, when primary studies express the same variables through different instruments (and different units of measurement) we will use the standardised mean difference (SMD).
Dealing with missing data
In case there is inadequate information relative to estimate effects, such as number of patients, means, measures of uncertainty (standard deviation or error), or number of events and patients, we will try to contact the main authors of primary studies. When impossible to acquire missing data such as standard deviations, we will present data in the text and/or tables. The same strategy will be used for results with binary data or continuous data that are not normally distributed.
Assessment of heterogeneity
The heterogeneity of estimate effects between the included studies will be assessed by visual inspection of the forest plot (analysis) along with consideration of the test for heterogeneity and the I2 statistic.
Data synthesis
If considered appropriate, results of comparable groups of trials will be pooled. Initially we will use the fixed‐effect model and 95% confidence intervals. However, since we expect a diversity of clinical and methodological characteristics in the included studies, it is likely that we will choose to use the random‐effects model.
Subgroup analysis and investigation of heterogeneity
We would aim to perform subgroup analyses in order to explore effect size differences in relation to the type of injury (Rockwood classification types) and whether the surgery involved ligament reconstruction or not.
Sensitivity analysis
Also we will perform sensitivity analyses investigating the effects of allocation concealment, the inclusion of studies with a high risk of bias, and the substitution of a reasonable range of data if data are missing.
| Type | Description |
| Type I | A mild injury involving spraining the acromioclavicular ligaments while leaving the joint intact. |
| Type II | Injury where the acromioclavicular ligaments are torn and acromioclavicular joint is disrupted, while the coracoclavicular ligaments are intact. |
| Type III | Injury involves complete tearing of both the acromioclavicular and coracoclavicular ligaments with 100% dislocation of the joint. |
| Type IV | Injury is a complete acromioclavicular dislocation with posterior displacement of the clavicle through or into the trapezius fascia |
| Type V | Injury is a complete acromioclavicular dislocation with 100% to 300% superior dislocation of the clavicle. It can involve significant disruption of the deltotrapezial fascia. |
| Type VI | Injury involves inferior displacement of the clavicle into a subacromial or subcoracoid position. |
| Items | Scores | Notes |
| (1) Was the assigned treatment adequately concealed prior to allocation? | Yes = method did not allow disclosure of assignment. | Cochrane code (see Handbook): Clearly yes = A; Not sure = B; Clearly no = C. |
| (2) Were the outcomes of participants who withdrew described and included in the analysis (intention‐to‐treat)? | Yes = withdrawals well described and accounted for in analysis. | |
| (3) Were the outcome assessors blinded to treatment status? | Yes = effective action taken to blind assessors. | |
| (4) Were important baseline characteristics reported and comparable? | Yes = good comparability of groups, or confounding adjusted for in analysis. | Although many characteristics including hand dominance are important, the principal confounders are considered to be age, gender, type of lesion (dislocation or subluxation). |
| (5) Were the trial participants blind to assignment status after allocation? | Yes = effective action taken to blind participants. | |
| (6) Were the treatment providers blind to assignment status? | Yes = effective action taken to blind treatment providers. | |
| (7) Were care programmes, other than the trial options, identical? | Yes = care programmes clearly identical. | Examples of clinically important differences in other interventions are: time of intervention, duration of intervention, difference in rehabilitation. |
| (8) Were the inclusion and exclusion criteria for entry clearly defined? | Yes = clearly defined (including type of fracture). | |
| (9) Were the outcome measures used clearly defined? | Yes = clearly defined. | |
| (10) Were the accuracy and precision, with consideration of observer variation, of the outcome measures adequate; and were these clinically useful and did they include active follow up? | Yes = optimal. | |
| (11) Was the timing (e.g. duration of surveillance) clinically appropriate? | Yes = optimal (> 1 year) |
