Acute Acromioclavicular Dislocation: Epidemiology, Natural History and Analysis of Prognostic Factors
Condition: Acromioclavicular Joint Dislocation
MeSH terms: Joint Dislocations
Study type: Observational

Summary: 
      Aim:

      To evaluate non-operative treatment of acute acromioclavicular (AC) joint dislocation and
      define prognostic factors to guide the choice of treatment in order to develop an
      individualized treatment algorithm.

      Objectives:

        1. To investigate whether a sub classification of Rockwoods type III in a stable type IIIA
           and an unstable type IIIB, as suggested by ISAKOS (International Society of Arthroscopy,
           Knee Surgery and Orthopaedic Sports Medicine), is clinically relevant. Clinically
           relevant is defined as a difference in the WOSI score of >14%

        2. To evaluate clinical, functional and radiological results, along with patient-reported
           health, 6 weeks, 3 months, 6 months and 1 year after acute AC dislocation

        3. To investigate whether specific factors are of prognostic value to the result after
           non-operative management of acute AC dislocation

        4. To investigate if Rockwoods classification of AC dislocations is of prognostic value for
           the rehabilitation after the injury.

      Type of study: Prospective cohort study. 100 patients will be included.

      Time schedule:

      Recruitment of patients is planned to begin November 2018. It is expected that the inclusion
      will span 1 year, provided an average of 2 patients included per week. With a 1-year
      follow-up for each patient the total study period is expected to be 2 years.

      Set-up:

      In the Capital Region of Denmark the majority of patients with acute AC joint dislocation are
      treated non-operatively. A collar'n cuff is applied in the emergency room and the patient is
      instructed to begin non-weight bearing exercises after 1-3 weeks.

      100 patients with acute AC-joint dislocation will be included in the cohort and evaluated at
      controls 6 weeks, 3 months, 6 months and 1 year after the injury. The patients will be
      identified from X-rays obtained in the Emergency Departments at three Danish Hospitals.

      At each control the patient will reply to 2 questionnaires regarding their shoulder-related
      function and quality of life, be evaluated through 5 clinical tests, and 2 different X-rays
      of the AC-joint will be obtained.
    

Detailed description: 
      Introduction:

      Acromioclavicular (AC) joint dislocations are common injuries accounting for 9-12% of all
      injuries to the shoulder girdle. The injuries are graded according to Rockwoods
      classification type I-VI. There is consensus on the treatment of Rockwood type I and II which
      rehabilitates well with conservative treatment, and for high-grade injuries of types IV, V
      and VI, which usually requires surgery. However the treatment of the most common type, type
      III, has remained controversial for the last 30 years. To assess this problem, ISAKOS
      (International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine) Upper
      Extremity Committee in 2014 provided a modified Rockwood classification, suggesting a
      sub-classification of the debated type III in a stable type IIIA and an unstable type IIIB.

      The purpose of this sub-classification is to identify and differentiate patients, who are
      expected to rehabilitate well with conservative treatment from those who would benefit from
      early surgical intervention, i.e. type IIIA and IIIB. Type IIIA is considered stable and is
      characterized by absence of scapula dyskinesia and no overriding of the clavicle to acromion.
      Type IIIB is characterized by presence of scapula dyskinesia and no overriding of the
      clavicle to acromion.

      Aim:

      To evaluate non-operative treatment of acute acromioclavicular (AC) joint dislocation and
      define prognostic factors to guide the choice of treatment in order to develop an
      individualized treatment algorithm.

      Objectives:

        1. To investigate whether a sub classification of Rockwoods type III in a stable type IIIA
           and an unstable type IIIB, as suggested by ISAKOS, is clinically relevant. Clinically
           relevant is defined as a difference in the WOSI score of >14%

        2. To evaluate clinical, functional and radiological results, along with patient-reported
           health, 6 weeks, 3 months, 6 months and 1 year after acute AC dislocation

        3. To investigate whether specific factors are of prognostic value to the result after
           non-operative management of acute AC dislocation

        4. To investigate if Rockwoods classification of AC dislocations is of prognostic value for
           the rehabilitation after the injury.

      Study design: The study is carried out as a prospective cohort study. 100 patients will be
      included.

      Time schedule:

      Recruitment of patients for the study is planned to begin in November 2018. It is expected
      that the inclusion will span 1 year, provided an average of 2 patients included per week.
      With a 1-year follow-up for each patient the total study period is expected to be 2 years.

      Methods:

      Recruitment:

      100 patients with acute AC-joint dislocation from the Emergency Departments at three
      different hospitals in the Capital Region of Denmark (Hvidovre, Glostrup and Amager
      hospitals) will be included in the cohort. Patients with superior displacement of the
      clavicle to the acromion are of interest to the study.

      At the Emergency Departments, the patients will receive the standard conservative treatment
      of collar'n cuff for 1-3 weeks.

      To identify patients, all X-rays of the AC-joint and the clavicle obtained at the three
      hospitals will be evaluated weekly, identifying the presence and degree of potential AC
      dislocations. If the patient meet the inclusion criterias, he or she will be invited to
      participate in the cohort.

      Follow-up:

      Participants will be offered an appointment in the ambulatory for baseline evaluation.
      Follow-up measurements will be performed at 6 weeks, 3 months, 6 months and 1 year after the
      injury. The study's primary endpoint is at the 3 month mark.

      At the follow-ups, participants will be evaluated clinically, functionally and
      radiologically. Primary outcome measure is the patient's self-reported shoulder-related
      quality of life, evaluated using WOSI (Western Ontario Shoulder Instability Index). As
      secondary outcomes patients will evaluate their functional limitations and pain with SPADI
      (Shoulder Pain and Disability Index), the cosmetic results with NRS (Numeric Rating Scale)
      and attend a clinical evaluation regarding range of motion (ROM), the presence of scapular
      dyskinesia, antero-posterior/superior-inferior instability of the clavicle and O'Briens test.
      Two radiographs of the AC-joint will be obtained to determine the coraco-clavicular distance
      as well as the degree of overriding of the clavicle to acromion.

      It is expected that a number of patients in the cohort, due to sustainable pain and
      non-acceptable disability, will be offered surgical treatment. This group will be followed
      exactly like the group of conservatively treated patients. The two groups will be compared
      both according to their demographical data and their outcome.

      Discontinuation:

      Each patient can choose to withdraw from the trial at any time. A patient may also be
      withdrawn from the trial at any time based on the investigators' discretion.

      Data Registration:

      All relevant data is recorded and stored in a specially designed database; RedCap. The data
      registration has been approved by the Danish Data Protection Agency and The Ethical committee
      of the Capital Region of Denmark.

      Statistics:

      The cohort will be described descriptively regarding demographic parameters as well as
      primary and secondary outcomes. The change of the outcomes over time will be described using
      relevant statistics according to the characteristics of the variables and if necessary the
      normal distribution. A regression analysis will be used to evaluate the association between
      prognostic factors and recovery.

      Sample size:

      The sample size is calculated to detect if a clinical relevant difference in WOSI-score
      exists between a group with stable (type IIIA) and unstable (type IIIB) AC dislocations. The
      calculation is based on a clinical relevant difference in WOSI-score of 14%, a standard
      deviation, SD, of 20%, a significance level of 0,05 and a power of 90%. According to this
      calculation the study demands 88 patients but because of the risk of drop-out, 100 patients
      will be included.

      Ethical considerations:

      The project is approved by the National Committee on Health Research Ethics. The purpose of
      the study is to follow the natural history of a common injury, where guidelines for the
      treatment already exist. There is no intervention in the study - patients enrolled will
      receive the standard treatment in the Emergency Departments. They will be offered
      standardized physiotherapy and extra controls, which is considered an advantage for the
      patients as they receive a thorough follow-up and examination of the healing process. The
      disadvantages for the patients are: 1) Participation in the study is time-consuming: Patients
      need to attend 4 extra controls, each lasting approximately 1h. 2) Exposure to radiation: At
      each control, 2 x-rays of the shoulder will be obtained. However the radiation exposure is
      very small, only 0,1-0,3 mSv/ x-ray, equivalent to a few weeks of background radiation. It is
      believed that the potential benefits for both patients in the study and future patients with
      AC dislocations (thorough follow-up and individualized treatment,) exceed the the potential
      inconveniences (additional follow-up audits and light exposure to radiation).
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        100 patients with acute acromioclavicular dislocation, admitted to the Emergency
        departments at Hvidovre, Glostrup and Amager Hospitals (Copenhagen). All patients will be
        treated according the standard regimen.
      
Keywords: Acromioclavicular Joint Dislocation; AC joint dislocation; Treatment; Conservative treatment; Type III AC dislocation; Grade III AC dislocation; AC joint; Rockwood; Rockwood type III; Rockwood grade III