Aims. To report our experience with trunnion corrosion following metal-on-polyethylene
total hip arthroplasty, in particular to report the spectrum of
presentation and determine the mean time to presentation. Patients and Methods. We report the presenting symptoms and signs, intraoperative findings,
and early results and complications of operative treatment in nine
patients with a mean age of 74 years (60 to 86). The onset of symptoms
was at a mean of seven years (3 to 18) after index surgery. Results. Patients presented with a variety of symptoms including pain,
limp and rash. The preoperative mean serum cobalt level was 7.1 ppb
(2.2 to 12.8) and mean serum chromium level was 2.2 ppb (0.5 to
5.2). Metal artifact reduction sequence (MARS) MRI showed fluid
collection and possible pseudotumour formation in five hips, fluid
collection in two hips, and synovitis/debris in one hip, with no
MRI in one patient. Acetabular revision was performed in three patients,
six patients underwent liner and head exchange only. The postoperative
metal levels decreased in all patients: mean cobalt 0.5 ppb (0 to
1.8) and mean chromium 0.9 ppb (0 to 2.6) at a mean of five months
(3 to 8) postoperatively. Seven patients had good pain relief and
no complications at one year. There were two
Given the increasing number of total hip arthroplasty
procedures being performed annually, it is imperative that orthopaedic
surgeons understand factors responsible for instability. In order
to treat this potentially complex problem, we recommend correctly
classifying the type of instability present based on component position, abductor
function, impingement, and polyethylene wear. Correct classification
allows the treating surgeon to choose the appropriate revision option
that ultimately will allow for the best potential outcome. Cite this article:
