Background and rationale:
ACJD can be either managed conservatively or surgically. Concerning functional outcomes, it
usually accepted that ACJD Rockwood state I and II should be treated conservatively.It is
still debated whether grade III should be treated surgically or not, and only experts opinion
suggest that grade IV and V has better surgical outcome than conservative. The main
literature failed to demonstrate the superiority of the surgical management for functional
outcomes. Despite this, operative management results in a better cosmetic outcome, but
conservative management is associated with a lower duration of sick leave and lesser costs.
It has been purposed by a worldwide expert consensus (ISAKOS consensus) that dynamic
posterior clavicle impaction into the trapezius muscle (PICCAT) could be a predictive factor
of poor functional outcome in case of conservative management.
Hypothesis:
H0: ASES score at one year of follow-up is better with surgical management than with
conservative management.
H1: one year ASES score after conservative management is not inferior as after surgical
management. H1 will be first tested without PICCAT. If H1 is validated, it will then be
tested again including all patients, PICCAT or not.
Study design:
This multicentric case-control study is randomized 1:1 between conservative and surgical
treatment of ACJD. It is a non-inferiority trial that includes 176 patients that suffers from
acute ACJD Rockwood grade III-V. Conservative management will consist of a sling for 10 days
followed by a standardized physical therapy program, (Cote et al. 2010) and surgical
management will consist of coracoclavicular and acromioclavicular fixation and specific
rehabilitation. Clinical follow-up will last one year.
Statistical analysis
Non-inferiority statistical analysis will be performed upon appropriate unilateral 95%
confidence interval margin (Z = -1.645), with a non-inferiority margin of 6.4, corresponding
to ASES minimal clinically important difference. Analysis is planned in case of "intention to
treat" method, but, if patients of the conservative management group undergo surgery because
they are unsatisfied, ASES score will be measured prior surgery instead of at one year of
follow-up. No statistical adjustments on potential confounders are planned.
Sample size calculation:
ASES score minimal clinically important difference has been estimated to 6.4. ASES standard
deviation after surgical management of ACJD has been estimated to 9.7. If there is truly no
difference between the surgical and conservative treatments, then 80 patients are required to
be 90% sure that the lower limit of a one-sided 95% confidence interval (or equivalently a
90% two-sided confidence interval) will be above the non-inferiority limit of -6.4. Mazzoca,
one of the main authors of ISAKOS consensus (ISAKOS), has reported operating 50% of Rockwood
type III-V ACJD. From this, we can strongly suppose that 50% of Rockwood type III-V ACJD
presents PICCAT. Considering a 10% of drop-outs, we therefore need 80/(50%)*110% = 176
patients.