Primary meniscal-bearing knee replacements: 8- to 15-year followup

This study presents the survivorship data of a consecutive series of primary meniscal-bearing total knee replacements at one institution at 8 to 15 years followup. We reviewed 125 meniscal-bearing knee replacements in 93 patients at a minimum followup of 96 months (mean, 130 months; range, 96-191 months). The tibial and femoral components were cemented in 71 knees; uncemented femurs and tibias were used in 48 knees; and cemented tibias and uncemented femurs were used in six knees. One patient was lost to followup. Seventeen knees failed, three as a result of infection. Five knees were revised for loose tibial components and one for a loose femoral component. A second femoral component was identified as radiographically loose. All the loose components were uncemented. Five knees had reoperation for fractured bearings and one for a dislocated bearing. This knee was later rerevised for a loose uncemented tibia. One knee was revised for instability and a second knee was identified as grossly unstable but not revised. Kaplan-Meier survival analysis showed survivorship of approximately 90% at 9 years, which decreased to 71% at 15 years. Uncemented components had an increased aseptic loosening rate compared with cemented components. Meniscal-bearing replacements with cement fixation appeared successful, although bearing fracture seems to be a predominant failure mode at long-term followup.