Anatomical reconstruction to treat acromion fractures following reverse shoulder arthroplasty

Scapular fractures after reverse shoulder arthroplasty (RSA) are often associated with substantial shoulder impairment. Patient outcomes following either conservative or operative treatment have not been favourable, and consensus is lacking on the best treatment approach. We describe a technique for anatomic reconstruction of fractured lateral and basal acromion in patients at higher risk for diminished function or those for which conservative treatment has already failed.

Of the 95 patients who underwent RSA at our institution between December 2013 and December 2016, three had post-operative acromion fractures (type II). Two of these patients had secondary dislocation and one underwent conservative treatment that failed. In all three cases, the acromion was reconstructed using an open technique with plate and interfragmentary screw fixation.

After the acromial fracture and prior to reconstructive surgery, the shoulder function decreased substantially in all three cases. Following reconstruction, forward flexion improved from 53.0° to 127°, and abduction improved from 52.0 to 125°. The range of the Constant scores at the one year follow-up was 55-71, and the subjective shoulder value (SSV) was 50-90. One patient reached the same active range of motion (ROM) as her pre-fracture status, and the two other patients improved but did not regain the previous ROM level.

Acromion fractures after RSA are serious complications that have the potential to cause severe shoulder function impairment. Our fixation technique for anatomic lateral and basal acromion reconstruction was used safely to treat three patients with poor shoulder function due to secondary dislocation or non-unions.