Validity of the orthopedic POSSUM scoring system for the assessment of postoperative mortality in patients with pressure ulcers

In the treatment of pressure ulcers, assessment of systemic problems is an important yet difficult step in selecting either conservative or surgical therapeutic intervention. The surgical auditing system called the Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) and its orthopedic version (O-POSSUM), which gives a predictive mortality rate for the first 30 postoperative days, may be useful for assessing systemic status, but have yet to be sufficiently validated for patients with pressure ulcers. To assess the validity of POSSUM and O-POSSUM, 71 procedures on 50 cases were retrospectively statistically analyzed using receiver operating characteristic curves and goodness-of-fitness testing with the Hosmer-Lemeshow chi(2) test for logistic regression modeling. POSSUM and O-POSSUM showed satisfactory discriminatory power in receiver operating curve analysis. The validity of the values obtained by POSSUM and O-POSSUM was also confirmed. O-POSSUM was superior to POSSUM in both analyses. O-POSSUM is useful in assessing the systemic status of patients with pressure ulcers. Some patients with pressure ulcers show extreme systemic conditions. Assessment of systemic status with O-POSSUM contributes to daily clinical practice and future studies of treatments for pressure ulcers.