Outcomes and resource utilization in calcium pyrophosphate deposition disease patients who underwent total knee arthroplasty: a cross-sectional analysis.

This cross-sectional study aims to evaluate the predictors, outcomes, and resource utilization of total knee arthroplasty (TKA) in calcium pyrophosphate deposition disease (CPPD) patients. We used the US National Inpatient Sample database to identify CPPD and non-CPPD who underwent TKA from 2006 to 2014. Data collection included patient demographics and comorbidities. Outcomes following TKA included in-hospital mortality, complications, length of hospitalization, hospital charges, and disposition. Among the 5,564,005 patients who have undergone TKA, 11,529 (0.20%) had CPPD, with a median age of 72 years, and 53.7% were females. Compared with non-CPPD, patients with CPPD were more likely to be older (mean 72 vs 66 years; p < 0.001), male, white, and have Medicare insurance. CPPD patients were more likely to have ≥ 2 comorbidities calculated by the Charlson Comorbidity Index and discharge to an inpatient/rehabilitation facility. Regarding inpatient complications, myocardial infarction and knee reoperation were significantly more common in CPPD patients. TKA in CPPD patients was associated with significantly higher odds of increased length of stay (> 3 days) than those without CPPD (OR 1.43, 95% CI 1.37-1.49). There was no significant difference in the in-hospital mortality even after adjusting for possible confounders. CPPD patients who underwent TKA were more likely to have a longer hospital stay and discharge to a non-home setting than non-CPPD. Also, CPPD patients had a higher comorbidity burden and risk for myocardial infarction and reoperation.Key Points• This is the largest study to analyze data of CPPD patients who underwent TKA and compare them with non-CPPD patients, using a large nationwide database.• Compared to non-CPPD patients, TKA in CPPD patients is associated with a greater length of stay and disposition to a nursing/rehabilitation facility.• In-hospital complications such as myocardial infarction and reoperation were more frequently observed in CPPD patients than non-CPPD.• The results of this study should alert healthcare providers to develop strategies in order to improve outcomes of CPPD patients undergoing TKA.