These authors reviewed 98 patients in whom cemented humeral components revised to reverse total shoulders using a cement-within-cement technique.
The technical points made by this experienced author are worth noting:
(1) Visualization of the fins of the implant was required prior to extraction.
(2) A carbide punch was then placed under the proximal-medial portion of the stem. In cases in which the stem was collared, this was used for implant extraction. If no collar was present, a high-speed burr was used to create a ledge allowing for a direct axial force that would allow removal of the stem. (see "springboard notch discussion below).
(3) After stem removal, the remaining cement mantle was evaluated regarding the stability of the cement-bone interface
(4) Patients in whom frozensection microscopy revealed greater than 5 polymorphonuclear cells per high-power field, those with prior infection, and those with positive postoperative culture results were managed with an intravenous antibiotic regimen by an infectious disease specialist postoperatively.
(5) A diaphyseal intramedullary reamer was used to roughen the previous mantle and widen the intramedullary mantle.
(6) If the bone loss was deemed extensive enough to compromise the stability of the revision prosthetic stem, then an allograft-prosthetic composite (APC) was chosen to provide enhanced stability of the construct.
They compared 8 patients in whom humeral stem loosening developed with 90 patients whose stem remained fixed.
Using Mimics software, they measured the total area of the cement mantle (in square millimeters) and of the stem (in square millimeters) on 2-dimensional plain films preoperatively and at a minimum of 2 years after surgery.
In the group without loosening, the mean increase in the cement mantle area was 4380±12701 mm2 (P <.0001). In the group with loosening, the mean increase in the cement mantle area was only 811±4014 mm2 (P=.484).
The authors suggest that efforts to maximize the cement volume during reimplantation may lessen the chance of humeral stem loosening requiring additional revision.
Comment: All the technical points above are key. For example #6 says that cementing a round stem into a humerus without a metaphysis is unlikely to give rotational control.
Unfortunately, the authors do not provide details of the cementing technique including how to avoid voids as shown at the tip of the prosthesis in the right hand x-ray above. How is the canal cleaned and dried? Is the cement inserted in a more liquid than usual state? Is it pressurized? In cases of suspected infection, is it assumed that the cement will kill bugs in the canal rather than running a big risk of trying to remove all the cement?
Now for the springboard notch:
Because of concern about infection, a single stage revision was planned.
The available instrumentation did not enable the removal of the well-fixed humeral component. Thus we created a 'springboard notch' in the component using a pinecone bur. This notch enabled removal of the component by impacting upwards in the notch with a bone tamp.
After removal of the loose glenoid component, a standard stem was fixed securely using impaction allografting. The insertion of the standard stem was accomplished without needing to remove any additional bone.
In logging a springboard notch supports a plank inserted to give the logger a more advantageous approach to the trunk of the tree.
The authors suggest that efforts to maximize the cement volume during reimplantation may lessen the chance of humeral stem loosening requiring additional revision.
Comment: All the technical points above are key. For example #6 says that cementing a round stem into a humerus without a metaphysis is unlikely to give rotational control.
Unfortunately, the authors do not provide details of the cementing technique including how to avoid voids as shown at the tip of the prosthesis in the right hand x-ray above. How is the canal cleaned and dried? Is the cement inserted in a more liquid than usual state? Is it pressurized? In cases of suspected infection, is it assumed that the cement will kill bugs in the canal rather than running a big risk of trying to remove all the cement?
Now for the springboard notch:
Recently we had the opportunity to revise a total shoulder because of a loose glenoid component presenting 2.5 years after implantation. As seen in the x-rays below, the arthroplasty had been performed using a short 'canal sparing' humeral component.
The available instrumentation did not enable the removal of the well-fixed humeral component. Thus we created a 'springboard notch' in the component using a pinecone bur. This notch enabled removal of the component by impacting upwards in the notch with a bone tamp.
After removal of the loose glenoid component, a standard stem was fixed securely using impaction allografting. The insertion of the standard stem was accomplished without needing to remove any additional bone.
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To see a YouTube of our technique for a reverse total shoulder arthroplasty, click on this link.
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How you can support research in shoulder surgery Click on this link.
We have a new set of shoulder youtubes about the shoulder, check them out at this link.
Be sure to visit "Ream and Run - the state of the art" regarding this radically conservative approach to shoulder arthritis at this link and this link
Use the "Search" box to the right to find other topics of interest to you.
To see a YouTube of our technique for a reverse total shoulder arthroplasty, click on this link.
===
How you can support research in shoulder surgery Click on this link.
We have a new set of shoulder youtubes about the shoulder, check them out at this link.
Be sure to visit "Ream and Run - the state of the art" regarding this radically conservative approach to shoulder arthritis at this link and this link
Use the "Search" box to the right to find other topics of interest to you.
You may be interested in some of our most visited web pages arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'
