A randomized controlled trial comparing tibial migration of the ATTUNE cemented cruciate-retaining knee prosthesis with the PFC-sigma design

Abstract

Aims The primary objective of this study was to compare migration of the cemented ATTUNE fixed bearing cruciate retaining tibial component with the cemented Press-Fit Condylar (PFC)-sigma fixed bearing cruciate retaining tibial component. The secondary objectives included comparing clinical and radiological outcomes and Patient Reported Outcome Measures (PROMs). Methods A single blinded randomized, non-inferiority study was conducted including 74 patients. Radiostereometry examinations were made after weight bearing, but before hospital discharge, and at three, six, 12, and 24 months postoperatively. PROMS were collected preoperatively and at three, six, 12, and 24 months postoperatively. Radiographs for measuring radiolucencies were collected at two weeks and two years postoperatively. Results The overall migration (mean maximum total point motion (MPTM)) at two years was comparable: mean 1.13 mm (95% confidence interval (CI), 0.97 to 1.30) for the ATTUNE and 1.16 mm (95% CI, 0.99 to 1.35) for the PFC-sigma. At two years, the mean backward tilting was -0.43° (95% CI, -0.65 to -0.21) for the ATTUNE and 0.08° (95% CI -0.16 to 0.31), for the PFC-sigma. Overall migration between the first and second postoperative year was negligible for both components. The clinical outcomes and PROMs improved compared with preoperative scores and were not different between groups. Radiolucencies at the implant-cement interface were mainly seen below the medial baseplate: 17% in the ATTUNE and 3% in the PFC-sigma at two weeks, and at two years 42% and 9% respectively (p = 0.001). Conclusion In the first two postoperative years the initial version of the ATTUNE tibial component was not inferior with respect to overall migration, although it showed relatively more backwards tilting and radiolucent lines at the implant-cement interface than the PFC-sigma. The version of the ATTUNE tibial component examined in this study has subsequently undergone modification by the manufacturer. Level of Evidence: 1 (randomized controlled clinical trial) Cite this article: Bone Joint J 2020;102-B(9):1158–1166.

Early migration of a medially stabilized total knee arthroplasty

“…Although our study is not powered to evaluate clinical results, the scores on the FJS 50 and KOOS 30 , 51 are consistent with other TKAs. The polyethylene wear over two years was not clinically relevant (p = 0.116, Wilcoxon signed-rank test).…”

Roentgen stereophotogrammetric analysis: still a very valuable tool in the orthopaedic research armamentarium

“…A key study using model-based RSA compared migration, and clinical and patient-reported outcomes, between the ATTUNE design and PFC-sigma design. 21 The authors reported comparable tibial component migration at two years, but with more radiolucent lines observed at the implant-cement interface with the ATTUNE design, reinforcing that additional radiological parameters should be considered. Moreover, we need to be attentive to the failure mode, as there are exceptions in the behaviour of each implant.…”

“…27 The role of RSA has once again been vital in assessing micromotion and adjudicating the safety of these designs. 4,21,28 Other potential applications of RSA include in vivo linear and volumetric wear using model-based radiostereometric analysis. [29][30][31][32][33] Gascoyne et al 30 used modelbased RSA to evaluate linear and volumetric polyethylene (PE) wear in 101 TKA patients.…”

Tibial tray debonding from the cement mantle is associated with deformation of the backside of polyethylene tibial inserts

“…The findings of Kaptein et al 8 also agreed with those of Hoskins et al 30 They undertook a randomized controlled trial comparing the migration of the tibial component of 38 Attune cemented CR TKAs with 36 PFC-sigma TKAs. 8 At two years postoperatively, radiolucencies were seen between the Attune medial baseplate and the cement in 14 TKAs (42%) compared with three in Sigma PFC TKAs (9%). Staats et al 9 reviewed 529 primary cemented Attune and PFC Sigma TKAs which were implanted between 2014 and 2017 and also found a significantly higher incidence of radiolucent lines in the Attune group compared with the PFC group at 12 months postoperatively (35.1% vs 7.5%; p < 0.001).…”

“…[5][6][7] Others have reported an increased incidence of periprosthetic radiolucencies at early follow-up in patients treated the same designs of implant. 8,9 A number of reasons have been proposed. For the Attune (DePuy, USA), these include an increased constraint of the tibial PE, the absence of cement pockets on the tibial tray, changes in the roughness of the backside surface of the tibial tray, and stress-shielding secondary to the use of a thicker cobalt-chromium (CoCr) tray.…”