Table 2 Overview over all unfavorable events with criteria and frequency (n = number, RSA = reverse shoulder arthroplasty)

implant events (n = 4, 8.2%)

 malpositioning of the plate

yes or no

2

4.1%

 screw dislocation

yes or no

1

2.0%

 plate fracture

yes or no

1

2.0%

osteochondral events (n = 37, 75.5%)

 postoperative malreduction of the fracture

yes: NSA < 110° or > 150°, no: NSA 110–150°

3

6.1%

 head shaft malreduction

yes: > 5 mm, no: < 5 mm

12

24.5%

 greater tuberosity malreduction

yes: > 5 mm, no: < 5 mm

5

10.2%

 postoperative screw perforation

yes or no

1

2.0%

 secondary tuberosity dislocation

yes: > 5 mm, no: < 5 mm

1

2.0%

 tuberosity resorption

yes or no

1

2.0%

 osteonecrosis with screw perforation

yes or no

5

10.2%

 osteonecrosis without screw perforation

yes or no

7

14.3%

 secondary glenohumeral osteoarthritis

yes: painful and progressive, no: not painful and progressive

2

4.1%

infection (n = 1, 2.0%)

 late hematogenous infection

yes or no

1

2.0%

deep soft tissue events (n = 7, 14.3%)

 operated shoulder stiffness

yes or no

5

10.2%

 persistent shoulder stiffness

yes or no

2

4.1%

total unfavorable events

49

100.0%

patients with unfavorable event

27

27.6%