Monday, October 17, 2016

Failed prosthesis for fracture: the 'absent tuberosity sign'

One of the most difficult aspects of proximal humeral fracture surgery is getting the tuberosity reduced, fixed and healed. This problem is not made easier by placing a large humeral implant, which reduces the amount of bone left to reattach the displaced tuberosity.

Here's an example of this problem: a shoulder with pseudoparalysis after a post-traumatic deformity was treated with a total shoulder. Note on the AP view that the tuberosity is missing (there is no bone lateral to the arrow).

The axillary view shows the displaced, ununited greater tuberosity fragments (arrows) as well as some anterior translation of the humeral head on the glenoid.

Revision of this prosthesis to a reverse total will be complicated by (1) the bony ingrowth surface on the humeral prosthesis 

as well as (2) the bone loss that may occur when the glenoid component is removed.

Unless the tuberosity can be mobilized and fixed securely, a primary reverse total shoulder might have been a consideration at the index surgery, as shown in the x-ray below of a reverse total shoulder  (also with an 'absent tuberosity sign').

Note that, in contrast to our usual impaction grafting approach, this stem needed cement for control of prosthetic height and version.