Unusually High Rate of Early Failure of Tibial Component in ATTUNE Total Knee Arthroplasty System at Implant-Cement Interface
A novel design total knee arthroplasty (TKA) system has been introduced to improve patient outcomes and increase longevity. However, we have encountered a high rate of debonding of tibial implant-cement interface. In addition, multiple reports have been filed in Manufacturer and User Facility Device Experience database (MAUDE) with the same mechanism of failure. Therefore, we evaluated: clinical, radiographic, and intraoperative findings of patients who received this system and required a revision surgery, and findings from MAUDE database compiled to this date. We reviewed three hospital databases for patients who had revision TKA for tibial loosening at the implant-cement interface. This yielded 15 cases with a mean age of 61 years (range, 47-84). All patients received a novel knee system at another institution. Radiographic analysis was performed by treating orthopaedist. The MAUDE database was reviewed for reports of aseptic failure. Patients presented with pain on weight bearing, effusion, and decreased range of motion (ROM) within 2 years after surgery. Radiographic evaluation demonstrated loosening of the tibial components in 2 of 15 knees. This included cruciate retaining, posterior stabilized, fixed bearing, and rotating platform bearing designs. Intraoperative findings demonstrated gross loosening of the tibial component at the implant-cement interface. Femoral and patellar components were well fixed. There were 21 reports of tibial loosening at the implant-cement interface in MAUDE database in the past 2 months alone. Numerous other tibial failures were reported; however, the mechanisms of failures were not specified. Tibial component loosening is a rare complication of cemented TKA at short-term follow-up. Several possible reasons include increased constraint, reduced cement pockets, and reduced keel rotational stabilizers. The tibial component, which has greater torsional loads, has lower surface roughness than femoral component. We believe that this complication is underreported due to failure of radiographs to assess loosening. In addition, MAUDE database reporting is not consistent and competing companies cannot provide data on the revised components. In patients who have negative workup for a painful joint, one must consider the diagnosis of debonding.