[Treatment of symptomatic pseudarthrosis following acromion fracture with a patient-specific implant customized on a 3D-printed scapula].

Objective: Patient-specific osteosynthesis for pseudarthrosis of the acromion.

Indications: Symptomatic pseudarthrosis of the acromion at the level of a meta/mesacromion.

Contraindications: Infection; patient noncompliance regarding postoperative treatment protocol.

Surgical technique: Preoperatively, a patient-specific three-dimensional model of the scapula is printed. A locking compression plate (LCP) is individually adapted to this model. Via a dorsal surgical approach over the scapular spine, the pseudarthrosis is refreshed and autologous cancellous bone from the iliac crest is embedded in the fracture zone. This is followed by fixed-angle osteosynthesis with the individualized plate. In addition, tension banding with tapes is performed to reduce the tensile and shear forces on the fracture caused by the muscle.

Postoperative management: Consistent wearing of a shoulder-arm brace for 6 weeks postoperatively, active-assisted increase in range of motion for an additional 3 weeks, then gradual increase in weight-bearing and initiation of daily activities without additional weights until 12 weeks postoperatively.

Results: Treatment with the presented technique resulted in radiographic consolidation of the fracture and significant improvement in range of motion and pain at the 1‑year follow-up.