Does primary or secondary chondrocalcinosis influence long-term survivorship of unicompartmental arthroplasty?

Background:Coexistence of degenerative arthritis and calcium pyrophosphate dihydrate (CPPD) crystals (or radiological chondrocalcinosis) with osteoarthritis (OA) of the knees is frequent at the time of arthroplasty. Several studies suggest more rapid clinical and radiographic progression with CPPD than with OA alone. However, it is unclear whether chondrocalcinosis predisposes to higher risks of progression of arthritis in other compartments. QUESTION/ PURPOSES: We questioned whether chondrocalcinosis influences clinical scores, degeneration of other compartments, rupture of the ACL, survivorship, reason for revision, or timing of failures in case of UKA. METHODS: We retrospectively reviewed 206 patients (234 knees) who had UKAs between 1990 and 2000. Of these 234 knees, 85 had chondrocalcinosis at the time of surgery and 63 of the knees subsequently had radiographic evidence of chondrocalcinosis observed during followup. We evaluated patients with The Knee Society rating system and compared function and radiographic progression in the other compartments of patients without and with chondrocalcinosis. RESULTS: The use of conventional NSAIDs, radiographic progression of OA in the opposite femorotibial compartment of the knee, failure of the ACL, and aseptic loosening did not occur more frequently among patients with chondrocalcinosis. The 15-year cumulative survival rates were 90% and 87% for the knees without and with chondrocalcinosis, respectively, using revision to TKA as the end point. CONCLUSION: Our findings show chondrocalcinosis does not influence progression and therefore is not a contraindication to UKA. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.