Radiological characteristics of the calcaneal spurs in psoriatic arthritis.

OBJECTIVES: Inflammation at the entheses is a distinguishing feature of psoriatic arthritis (PsA). Enthesitis at the heel is the most common location at the Achilles and plantar fascia insertions on the calcaneus. This study aimed to 1) describe the morphological features and measurements of plantar calcaneal spurs in subjects with PsA and controls and 2) determine radiological features that differentiate between inflammatory and non-inflammatory calcaneal spurs. METHODS: Weight bearing lateral foot radiographs of 101 subjects with PsA and 38 control subjects without inflammatory arthritis were examined for plantar calcaneal and Achilles spurs. Three measurements were taken from each radiograph: plantar spur base, mid-segment, and length in millimeters. The differences in radiographic measurements, and the presence of fluffy periostitis of the plantar spurs were then compared between PsA patients and controls. RESULTS: Of the 101 subjects with PsA, 76 (75%) had at least one plantar calcaneal spur and 32 (31.5%) had at least one Achilles tendon spur, compared to 18 (47%) and 3 (8%) respectively in control group (p=0.004). Fluffy plantar periostitis was identified in 14 PsA subjects and none of the controls (p=0.01). The dimensions of plantar spurs were significantly different between groups - longer mid-segment distinguished patients with PsA from controls. CONCLUSIONS: Calcaneal spurs are more common in subjects with PsA than controls. Longer mid-segment measurement was associated with PsA. This study indicates that the presence of fluffy plantar periostitis and broad based and longer mid-segment dimensions are radiological features for inflammatory spurs.

Prevalence and predictors of reduced work productivity in patients with psoriatic arthritis.

OBJECTIVES: Psoriatic arthritis (PsA) is a unique inflammatory musculoskeletal disorder associated with psoriasis. Although high rates of absenteeism have been associated with PsA, less is known about the impact of the disease on the productivity of patients who remain at work. The aim of this study was to identify factors associated with reduced work productivity, as measured by the Work Limitations Questionnaire (WLQ), among patients with PsA. METHODS: Patients attending a single Psoriatic Arthritis Clinic were recruited for participation. Employed participants (including homemakers) first completed a Questionnaire for the Assessment of Work-Related Factors (QAWRF). Eligible participants then completed the WLQ. WLQ scores were used as the dependent variable in linear and logistic regression analyses. Independent variables assessed in this study include work characteristics, demographic factors, and clinical measures. RESULTS: One hundred and eighty-six eligible patients (60.9% males) returned their assessment forms for analysis. The mean reduction in work productivity due to illness was 4.3%. In univariate linear regression analysis, work productivity was significantly associated with sex, education status, Psoriasis Area and Severity Index (PASI), AJC, ESR, Functional Co-morbidity Index (FCI), and support at work; associations with gender, ESR, FCI, and medications were also significant in a reduced multivariate model. CONCLUSIONS: Work productivity was associated with demographic, clinical, and work-related factors in PsA. These variables may be useful in identifying patients who require more aggressive intervention, including the use of effective drugs to control disease activity and advocacy for a more supportive work environment.

The functional MICA-129 polymorphism is associated with skin but not joint manifestations of psoriatic disease independently of HLA-B and HLA-C.

A methionine/valine polymorphism at amino acid 129 of the major histocompatibility complex class I chain-related gene A (MICA-129) categorizes alleles into strong and weak binders of the natural killer (NK) and T-cell receptor NKG2D. We investigated whether MICA-129 is differentially associated with skin and joint manifestations of psoriatic disease (PsD) independently of human leukocyte antigen (HLA)-C and HLA-B in patients and controls from Toronto and St. John's. The MICA-129 methionine (Met) allele, particularly Met/Met homozygosity, was strongly associated with both cutaneous psoriasis (PsC) and psoriatic arthritis (PsA) independently of HLA-B and HLA-C in Toronto patients, and was also associated with PsA in St. John's patients, but with no additional effect of Met/Met homozygosity. No association remained after adjustment for HLA alleles in St. John's patients. MICA-129 was not associated with PsA when compared with PsC. We conclude that MICA-129 is a marker of skin manifestations of PsD that is independent of HLA class I in Toronto patients.