Is there an increased revision rate due to early tibial component loosening with a modern total knee arthroplasty design? A retrospective analysis from a large volume arthroplasty centre.

Background: The Attune TKR was introduced in 2011 as a successor to its predicate design The PFC Sigma. However, following reports of early failures, there are ongoing concerns related to increased loosening rates. Given the concerns, this study aimed to compare revision rates of the Attune implant to an established predicate, and other implant designs used in a high-volume arthroplasty center.

Methods: We identified 10,202 patients who underwent primary cemented TKR at our institution with a minimum of 1 year follow-up, involving 2406 Attune TKR (557 S +), 4642 PFC TKR, 3154 other designs. Primary outcomes were revision for all-causes, aseptic loosening of any component, and aseptic tibial loosening. Kaplan-Meier survival and Cox regression models were used to compare groups. Matched cohorts were selected for radiographic analysis.

Results: 308 knees were revised. The Attune cohort had the lowest risk of revision, with a rate of 2.98 per 1000 implant-years while the PFC and All Other Implant groups had a rate of 3.15 and 4.4 respectively. Aseptic loosing was the most common cause for revision, with 76% (65/88) involving the tibia. Survival analysis showed no significant differences between the Attune and other cohorts. Radiolucent lines were detected in 7.1% of the Attune S + group, 6.8% of the standard Attune group, and 6.3% of the PFC group, with no significant differences found between them.

Conclusion: This study represents the largest non-registry review of the Attune TKR in comparison to a predicate and other designs. There was no significant increased revision rate for all-cause revision or aseptic loosening, or peri-implant radiolucencies. It appears that increased loosening may not be as concerning as originally thought.

Level of evidence: Level III.