Radiostereometric analysis (RSA) allows an extremely accurate
measurement of early micromotion of components following arthroplasty. In this study, RSA was used to measure the migration of 11 partially
cemented fluted pegged glenoid components in patients with osteoarthritis
who underwent total shoulder arthroplasty using an improved surgical
technique (seven men, four women, mean age 68). Patients were evaluated
clinically using the American Shoulder and Elbow Surgeons (ASES)
and Constant-Murley scores and by CT scans two years post-operatively. Aims
Patients and Methods
Resurfacing of the humeral head is commonly used
within the UK to treat osteoarthritis (OA) of the shoulder. We present
the results of a small prospective randomised study of this procedure
using the Global CAP prosthesis with two different coatings, Porocoat
and DuoFix hydroxyapatite (HA). We followed two groups of ten patients
with OA of the shoulder for two years after insertion of the prosthesis
with tantalum marker beads, recording pain, Constant–Murley and
American Shoulder and Elbow Surgeons (ASES) outcome scores, and
using radiostereometric analysis to assess migration. The outcomes
were similar to those of other series, with significant reductions
in pain (p = 0.003) and an improvement in the Constant (p = 0.001)
and ASES scores (p = 0.006). The mean migration of the prosthesis
three months post-operatively was 0.78 mm (0.51 to 1.69) and 0.72
mm (0.33 to 1.45) for the Porocoat and DuoFix groups, respectively.
Analysis of variance indicated that the rate of migration reached
a plateau after three months post-operatively in both groups. At
follow-up of two years the mean migration was 1 mm ( The addition of a coating of HA to the sintered surface does
not improve fixation of this prosthesis. Cite this article:
