Determination of the PRIMA Stem size
The instruments feature color coding to support the surgical team using the system. The PRIMA Stem is available in 5 sizes and the table below indicates the corresponding color coding.
PRIMA Stem Size Color Code #1 No Color #2 Yellow #3 Orange #4 Magenta #5 Blue
Figure 13
Figure 14
Carefully remove all humeral osteophytes from the humeral head so that the size of the PRIMA Stem can be determined. Determine the size of the PRIMA stem using the metaphyseal sizer rings. As optional, the spike bushing could be used in this surgical phase to hold the metaphyseal sizer ring onto the resected humeral plane. Pre-assemble the spike bushing to the sizer ring on the back table, till the first click is heard (Figure 13). Then slide the metaphyseal sizer ring into the Ø 6 mm intramedullary rod and place it over the resected surface (Figure 14). The PRIMA stem will be aligned with the intramedullary canal of the humerus. To determine the correct implant, the outer rim of the selected ring should be central on the resected humeral surface without overlying the cortex (Figure 15A). The metaphyseal sizer ring has protrusions that are 3mm larger than the outer rim of the ring and should be used as reference tool for the positioning. The protrusions should be contained within the trabecular portion of the resected surface (Figure 15B) and should not extend beyond the cortical rim. If not satisfied substitute the sizer ring with a different size.
Ok
On limit
Over dimensioned
Figure 15A
3mm
Figure 15B
17
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