Objective. To determine the probability that patients with psoriatic a
rthritis (PsA) will require musculoskeletal surgery. To identify facto
rs predictive of surgery in patients with PsA. To determine the clinic
al outcome of patients with PsA who underwent surgery compared to pati
ents who did not. Methods, The database of the Psoriatic Arthritis Cli
nic was searched to identify individuals who had undergone musculoskel
etal surgery. Biological and clinical data such as erythrocyte sedimen
tation rate (ESR), rheumatoid factor, clinical pattern, nail changes,
functional class, number of inflamed joints, and radiological damage,
as well as health scores such as Arthritis Impact Measurement Scale 2
(AIMS-2), SF-36, and Health Assessment Questionnaire (HAQ) were availa
ble for these patients. Patients who had surgery were compared to thos
e who did not. Results, Out of 444 patients with confirmed PsA, 31 had
musculoskeletal surgery (6.98%). This probability increased with the
duration of PsA. Surgery patients had their first operation at an aver
age of 13.9 years (range 1-46) after onset of joint disease. Age at on
set of PsA, clinical pattern, constancy of clinical pattern over time,
rheumatoid factor, functional class, symmetry, nail changes, and the
time separating the onset of skin disease and the onset of joint disea
se were not significantly different at the 0.05 confidence level. Pati
ents who had surgery had significantly more radiological damage (p < 0
.001) and more actively inflamed joints (p < 0.02) at first assessment
than patients who did not. AIMS2, SF-36, and HAQ scores at final revi
ew were not statistically different across both groups. Conclusion. In
our patients the probability of having musculoskeletal surgery for Ps
A was 7%. It increased with disease duration. Patients had their first
surgery after an average of 13 years. The number of actively inflamed
joints and the extent of radiological damage at first assessment were
highly predictive of subsequent surgery: patients with the highest nu
mbers of severely affected joints, both clinically and radiologically,
were more likely to have surgery. ''Baseline characteristics'' such a
s ESR, rheumatoid factor, functional class, clinical pattern, nail cha
nges, and symmetry were not predictive of subsequent orthopedic surger
y.