The uncemented ATTUNE knee outcome study (ATKOS); Short-term clinical improvements in advanced knee osteoarthritis

Background: The functional patient-reported outcome measures (PROMs) of the newly introduced uncemented cruciate-retaining rotating-platform ATTUNE total knee arthroplasty (TKA) have not yet been documented. This preliminary study aims to evaluate the short-term functional PROMs. Secondary objectives include evaluating the clinical outcomes, and rates of revisions and reoperations. Method: Preliminary data from an ongoing 10-year multi-center observational study on patients with osteoarthritis receiving an uncemented ATTUNE were analyzed. Surgeries were performed with mechanical alignment and without patellar resurfacing. PROMs (Oxford-knee-score [OKS], Forgotten-joint-score [FJS], Anterior-Knee-Pain-Scale [KUJALA], EQ-5D-5L, NRS-pain-scale, TEGNER and UCLA) and clinical examination results were collected at 6 weeks, 6 months, and 1 year. Linear-mixed-models analyzed PROMs and clinical data, while revision rates were estimated using Kaplan-Meier survival analysis. Results: After excluding 171 knees with less than one year of follow-up, a total of 260 knees were included in the analysis. The cohort comprised 57 % women, of 67 years (standard deviation [SD] = 9.5) old, with a follow-up of 2.0 years (SD 0.9). All measured PROMs showed significant improvements at 6 months and 1 year compared to baseline. At 1 year postoperatively, the scores were as followed: OKS 36.8 (CI 35.7–38.0), FJS 53.1 (CI 49.7–56.6), KUJALA 71.7 (CI 69.5–73.8), EQ-5D-5L index 0.88 (CI 0.86–0.90), NRS at rest 1.2 (CI 0.9–1.4), NRS during movement 2.2 (CI 1.8–2.5), TEGNER 3.4 (CI 3.1–3.6), and UCLA 5.6 (CI 5.3–5.9). The revision rate was 1.9 % (CI 1.9–1.9) at 1 and 2 years, and 2.8 % (CI 2.8–2.8) at 3 years. Revisions included one case of aseptic loosening of the tibial component. Conclusions: The results suggest that the uncemented cruciate-retaining rotating-platform ATTUNE TKA provides substantial short-term functional improvements compared to the preoperative state, which are at least equivalent to other well-established TKAs. Longer follow-up is necessary to determine if these findings are sustained, particularly regarding revision rates. Level of evidence: Level II (prospective cohort study).