smith&nephew RT-PLUS Surgical Technique page 38

The tibial sizer trial and the handle are assembled and placed intramedullary with the tibial
chisel guide over the extension for trial stem (Ø 8 mm) and applied onto the proximal bone
resection.
The tibial sizer trial should completely cover the cortex without projecting beyond the tibia.
In case of doubt, a lateral projection is preferred, because a medial projection may cause
irritation of the pes anserinus. If the projection is not acceptable, a smaller size should be
used (pay attention to the combination!). The correct tibial size is then determined.
Notes
By use of tibial blocks, the corresponding blocks are to be attached to the tibial sizer. Note
the corresponding heights (5 mm, 10 mm or 15 mm) and side (Rlat/Lmed or Llat/Rmed). The
15 mm tibial blocks are anatomically bent M/L and posterior. Therefore, the undercontour is
always a size smaller than the upper contour.
Size 2 tibial component cannot be combined with size 4 femoral component.
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Controlling the joint gaps
The tension in fl exion and extension is checked
with spacers. The spacers (8, 11 and 14) re-
present the femoral component and the full
tibial component heights (tibial component
and tibial insert).
When using augmentation blocks, the corre-
sponding spacer blocks must be fi xed to the
spacer. Note the corresponding thickness
(5 mm, 10 mm or 15 mm). These can be fi xed
either on the tibial side or on the femoral
side.
If necessary, further release or resection is
performed.
Note
To release the spacer blocks, a long pin can
be inserted in the hole and used as a lever.
The two bone pins in the tibia are then
removed.
Tibial size determination
The chosen trial stem is attached to the exten-
sion for trial stem (Ø 8 mm) and with the mod-
ular handle carefully inserted into the tibial
IM canal so the line marked with PRIMARY
respectively REV. is approximately level to
the proximal bone resection. The modular
handle is now removed. It is important to
avoid putting excessive pressure in the tibial
IM canal.