Comorbidity could alter joint arthroplasty prognosis

Dec 22 2012

By Lynda Williams, Senior medwireNews Reporter

The long-term outcome of hip and knee arthroplasty may be significantly influenced by comorbidity, suggest results from a large register-based study of over 96,000 osteoarthritis patients.

Data for 43,747 patients who underwent primary total hip replacement and 53,007 patients who underwent primary total knee replacement showed that patients with one or more of the specified diseases were 1.16 and 1.23 times, respectively, more likely to have poor prosthesis survival than those without.

"In some disease groups, the effect on survival rates was clinically highly significant, which may impair the cost-effectiveness of joint replacements in affected individuals," say Esa Jämsen (Coxa, Hospital for Joint Replacement, Tampere, Finland) and co-authors.

"The mechanisms of failure and factors predicting the outcomes within the disease groups (like duration of disease and its treatment) warrant further research in order to improve the surgical outcomes in these patients."

Multivariate analysis showed that patients with cardiovascular disease, defined as coronary heart disease, atrial fibrillation or heart failure, were significantly more likely to require revision of hip or knee arthroplasty than those without (hazard ratios [HRs]=1.19 and 1.29). A similar relationship was also found for patients with psychotic disorders, including mania, schizophrenia, and schizophrenia-like illness (HRs=1.41 for both).

Patients with hypertension or diabetes were significantly more likely than those without to require revision knee arthroplasty within 5 years than those without (HRs=1.14 and 1.27, respectively), while patients with depression were at increased risk for early hip arthroplasty revision (HR=1.50).

Patients with cancer were at increased risk for both poor hip arthroplasty survival (HR=1.27) and a revision of knee arthroplasty more than 5 years after surgery (HR=2.21) compared with patients without malignancy.

By contrast, neurodegenerative and pulmonary diseases had no impact on knee and hip prosthesis survival, the researchers report in the Annals of Rheumatic Diseases.

Jämsen et al say that while obesity may explain some of the link between cardiovascular disease and diabetes with the need for revision surgery, previous research has shown no association between obesity and the development of radiolucent lines surrounding prosthesis.

"The mechanisms explaining how cardiovascular diseases might affect prosthesis survival and the combined effects of cardiovascular diseases and diabetes warrant further research using clinical rather than register-based data," they write.

The team suggests that bone quality leading to prosthesis loosening could explain the link between cancer and comorbidity. While pain and joint scores are significantly associated with depression, the researchers note that the impact of depression could also be due to other comorbidities.

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