Badawy, Mona, et al. “Primary Constrained and Hinged Total Knee Arthroplasty: 2- and 5-Year Revision Risk Compared With Unconstrained Total Knee Arthroplasty: A Report on 401 Cases from the Norwegian Arthroplasty Register 1994–2017”. Acta Orthopaedica, vol. 90, no. 5, June 2019, pp. 467-72, doi:10.1080/17453674.2019.1627638.