Thursday, July 28, 2016

Corrosion in shoulder arthroplasty humeral components

Tribocorrosion in shoulder arthroplasty humeral component retrievals.

These authors studied 28 implants with a mean implantation time of 6.2 ± 6.0 years. Thirteen of the implants were the Tornier Aequalis and the rest were a mix of 11 other models. All models had a cobalt-chromium humeral head and a titanium humeral stem or anchor. The majority of designs had a male taper on the stem side.

Corrosion was present on 32% of heads and 38% of stems, whereas fretting was present on 36% of heads and 46% of stems. The greatest damage was in the lower zone of the taper, where the connection may be exposed to the surrounding joint fluid.

Comment: This paper is very similar to that discussed in a prior post (see this link), although the conclusions about the location of the worse corrosion are somewhat different.

Modularity is an advantage in customizing the implant to the shoulder. Time will tell whether corrosion offsets this advantage.