A ten-year prospective randomized trial comparing non-operative treatment to hook plate fixation for Rockwood III acromio-clavicular dislocation.

Background: Despite new modern surgical techniques, no short-term functional differences have been demonstrated between operative and non-operative treatment for acute acromio-clavicular (AC) dislocations Rockwood III-V. Few studies describe the long-term clinical and radiological results of these lesions. We aim to compare the one- and ten-year outcome of patients either treated non-operatively or with hook plate fixation for Rockwood III AC lesions.

Hypothesis: Non-operative treatment is not inferior to surgical treatment at short and long-term follow-up when considering patient function and radiological degenerative changes.

Patients and methods: Prospective randomized trial including 56 consecutive patients aged between 18 and 60, admitted to a level one trauma center for an acute Rockwood III AC joint dislocation. Patients were randomized to two groups: non-operative or surgical treatment with hook plate. Outcome measures were obtained by an independent examiner and included Constant score, DASH score, complications, and radiological results at one and minimum ten years (last visit delayed due to COVID-19 pandemia). Data analysis with a 5% alpha error.

Results: We observed no difference between the two groups for the Constant score at one year (non-operative 93.3 ± 7.4 vs surgical 92.7 ± 6.7, p = 0,41) and ten years (93.3 ± 10 vs 98.2 ± 5.2, p = 0,08). Similar results for all other clinical outcomes were censed. The reoperation rate was higher in the surgical group (88.5 vs 3.3%, p < 0,01), but consisted of hardware removal in most cases. Radiological degenerative changes were present in both groups at ten years (non-operative 33.3% vs surgical 50%, p = 0,24).

Discussion: This study confirmed that non-operative treatment was not inferior to surgical treatment with a hook plate for acute Rockwood III AC joint lesion at both short and long-term follow-up periods. Patients treated non-operatively achieved very high clinical scores, nearly equivalent to normal function. Further research should identify the patient-specific risk factors associated with the rare cases of failed non-operative treatment.

Level of evidence: I; randomized controlled study, therapeutic.