Table 1.
Explanted RTKA implants and the conical profile of their stem extensions, as measured using the preoperative planning software MediCAD
| RTKA model (manufacturer) | No | Stem design | Conical angle | Conical proportion |
|---|---|---|---|---|
| MUTARS® GenuX® MK (Implantcast, Buxtehude, Germany) | 4 | Cy (Co) | 0° (8°) | 30% proximal |
| Endo-Model RH prosthesis (Waldemar LINK, Hamburg, Germany) | 17 | Co | 2° | 100% |
| Zimmer® NexGen® LCCK (ZIMMER BIOMET, Warsaw, USA) | 10 | Cy | 0° | 0% |
| Zimmer® NexGen® RHK (ZIMMER BIOMET, Warsaw, USA) | Cy | 0° | 0% | |
| P.F.C.™ SIGMA TC3 (DePuy Synthes Joint Reconstruction, Warsaw, USA) | 6 | Cy (Co)* | 0° (1.6°–2.7°) | 0% (100%) |
| LCS COMPLETE™ RKS (DePuy Synthes Joint Reconstruction, Warsaw, USA) | 2 | Cy (Co)* | 0° (1.6°–2.7°) | 0% (100%) |
| M.B.T. Revision Tray Monobloc (DePuy Synthes Joint Reconstruction, Warsaw, USA) | 1 | Co* | 8° | 100% |
| LEGION® RK or HK (Smith & Nephew, Inc., Memphis, USA) | 3 | Cy | 0° | 0% |
| RT-PLUS Modular Knee (Smith & Nephew, Inc., Memphis, USA) | 4 | Cy* | 0° | 0% |
| EndoRo® AS KRS (B.Braun, Aesculap AG, Tuttlingen, Germany) | 3 | Cy (Co) | 0° (2–3°) | 23% distal |
*Depending on the length and fixation technique, some otherwise cylindrical stems may also possess conical profiles [e.g., the cemented tapered universal stems with length 90–150 mm and conical angles 1.6°–2.7° (DePuy)]. Furthermore, while the RT-PLUS modular knee possesses a cylindrical stem, the cemented RT-PLUS monobloc has a conical stem design (95 mm/4.5°–18°). Other RTKA implants may have different stem profiles within the same model depending on the side of the joint, usually with cylindrical designs on the femoral side and conical designs on the tibial side [e.g., the M.B.T. Revision Tibia Tray (DePuy) with a monobloc conical stem (61.8 mm/8°), and the Natural Knee II Revision (Zimmer) with cylindrical femoral stems and conical tibial stems (90–215 mm/12°–5.1°)]
CAVE: measurements may vary from the original manufacturer’s values