J Knee Surg 2018; 31(01): 087-091
DOI: 10.1055/s-0037-1602132
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Patient-Reported Outcomes following Single- and Multiple-Radius Total Knee Replacement: A Randomized, Controlled Trial

Nadeem Mushtaq1, Alexander D. Liddle2, David Isaac3, Katherine Dillow4, Paul Gill5
  • 1Department of Trauma and Orthopaedic Surgery, Imperial College Healthcare NHS Trust, London, United Kingdom
  • 2University College London Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, University College London, Brockley Hill, Stanmore, United Kingdom
  • 3Department of Trauma and Orthopaedic Surgery, Torbay Hospital NHS Foundation Trust, Torbay, United Kingdom
  • 4Department of Trauma and Orthopaedic Surgery, Dartford and Gravesham NHS Trust, Dartford, United Kingdom
  • 5Department of Trauma and Orthopaedic Surgery, Princess Royal University Hospital, London, United Kingdom
Further Information

Publication History

24 August 2015

09 March 2017

Publication Date:
05 May 2017 (eFirst)


Although single-radius (SR) designs of total knee replacement (TKR) have theoretical benefits, the clinical advantage conferred by such designs is unknown. The aim of this randomized, controlled study was to compare the short-term clinical outcomes of the two design rationales. A total of 105 knees were randomized to receive either a single radius (Scorpio, Stryker; SR Group) or multiple radius (AGC, Zimmer Biomet; MR group) TKR. Patient-reported outcomes (Oxford Knee Score [OKS] and Knee Society Score [KSS]) were collected at 6 weeks, 6 months, and 1 year following surgery. No knees were revised. There was no difference in primary outcomes: OKS was 39.5 (95% confidence interval [CI]: 36.9–42.1) in the SR group and 38.1 (95% CI: 36.0–40.3) in the MR group (p = 0.40). KSS was 168.4 (95% CI: 159.8–177.0) in the SR group; 159.5 (95% CI 150.5–168.5) in the MR group (p = 0.16). There was a small but statistically significant difference in the degree of change of the objective subscale of the KSS, favoring the SR design (p = 0.04), but this is of uncertain clinical relevance. The reported benefits of SR designs do not provide demonstrable functional advantages in the short term.