Fig 1.
Implant groups (A: short press-fit stem, B: short undersized stem, C: long press-fit stem, D: no stem), each combined with comparable M.B.T.
Revision tray and sleeve.
Fig 2.
Microscopic and macroscopic surfaces of a tibial tray, combined with sleeve and distal stem.
Fig 3.
Connection of an adapter to the intact bone using a template and adhesive resin.
Fig 4.
Simulated AORI Type I resection using a template, located 5 mm distal to the medial plateau.
Fig 5.
(A) High-resolution measuring device: entire setup used and (B) details of the measuring area.
Fig 6.
Location of the implant stability measuring points #1-#9 and bone flexibility measuring points b1-b6 as well as deformation sections Δb1,b2 to Δb5,b6.
Fig 7.
(A) Schematic of the applied axial torque around the longitudinal stem axis and (B) of the medio-lateral torque.
Fig 8.
(A) Rotational implant stability and (B) bending implant stability based on measured relative micromotions between bone and implant.
Comparison of Group D (no stem, depicted in blue, measuring points #1-#5) vs. Group A (short press-fit stem, depicted in red, measuring points #1-#8).
Fig 9.
(A) Rotational implant stability and (B) bending implant stability based on measured relative micromotions between bone and implant.
Comparison of Group D (no stem, depicted in blue, measuring points #1-#5) vs. Group C (long press-fit stem, depicted in red, measuring points #1-#9).
Fig 10.
(A) Rotational implant stability and (B) bending implant stability based on measured relative micromotions between bone and implant.
Comparison of Group A (short press-fit stem, depicted in red, measuring points #1-#8) vs. Group C (long press-fit stem, depicted in blue, measuring points #1-#9.
Fig 11.
(A) Rotational implant stability and (B) bending implant stability based on measured relative micromotions between bone and implant.
Comparison of Group A (short press-fit stem, depicted in red, measuring points #1-#8) vs. Group B (short undersized stem, depicted in blue, measuring points #1-#8).
Table 1.
Measured relative micromotions at the bone sections Δb1,b2 to Δb5,b6 are shown for intact bone Group E and for all implant groups (A-D) described as means and standard deviation (±SD).
The applied varus-valgus torque is separated into lateral and medial load condition to analyze bending bone deformation.
Fig 12.
Bone flexibility of Groups (A-E) in five different sections of the tibia during varus-valgus load application (separated into lateral ~blue and medial ~ red).
Deformations are given as relative micromotions between six bone measuring points in μm. Bar charts show the deformation of each group, while continuous lines resemble the deformation of an intact bone. Higher motions are accompanied by higher flexibility of the bone-implant compound and lower motions are accompanied by lower flexibility of the compound.