I had only one case in a SLE patient after 2 revisions . we used the Waldemar Link SADDLE PROSTHESIS unfortunately it became infected with chronic discharge eventually we had to remove the implant several years after surgery. The patient died shortly after the last operation.
Saddle prosthesis is not the same thing I'm talking about a stemmed cup like the McMinn stemmed cup (Link) which is an evolution of the Ring prosthesis.
Dear Dr. Pignatti,
You mean the use of periacetabular reconstruction endoprosthesis or custom-made tumor prosthesis for acetabular revision ? These models should be preserved for pelvic tumors and shoud not be used for acetabular reconstruction in revision surgery. They are very massive, one needs a wider resection and additional lost of bone stock. As Chanan says above, the results are not satisfactory. In surgery for pelvic malignancies their application is justified because of the character of the condition.
For acetabular reconstruction ( even in Paprosky 3A-B defect) the use of Zimmer Burch-Schneider cage yields satisfactory results.
The McMinn stemmed cup is no longer provided by Link. Another Implant I used to take is from the company Zimmer, they do not provide it any longer too. ImplantCast still sells a stemmed cup, even with bipolar bearing technology. But since this is a modular implant it in deed is a bit bulky.
Functional outcome after stemmed cup can be very good. I remember a patient whom i implanted a stemmed cup who received a functional result close to a primary hip. The indikation was acetabular metastasis.
Since the bone destruction in revision arthroplasty often resembles tumour like situations, there do exist indications (e.g. pelvic dicontinuity with severe bone loss) when You should take stemmed cups into Your therapeutic considerations, because augmented cups or cages can be overstrained.
Dear Dr Pignatti, in my hands the production of patient specific partial "pelvic reconstructs" works best if you do not have the possibility to implant a cup that fits in place by circular or at least 3-point loading. A Burch-Schneider construct may be helpfull, if this is a first revision case and mostly not Paprosky 3B or with pelvic discontinuity. With a custom made pelvic acetabular reconstruct, based on a CAD model following DICOM catscan data, it is possible not only to fix the construct according to the biomechanical needs but also according to your personal preferences. You may or may not reproduce the anatomical center of rotation, offset and leg length.
If the cancer belongs to advanced cancer and there is no chance for us to do more than a palliative treatment, such as metal acetabular cup+bone cement. If the cancer is found at a rather early period, we choose to do our best to clean out the cancer and to do the bone graft which could be from the head of the femur.
Dear dr. Pignatti, we use the ring Zimmer Burch-Schneider cage with eventual graft bone on the bottom and proximally, usually bone morcellised, sometimes with a tablet of the femoral head to close the bottom. But sometimes the flange can be short with iliac bone deficits proximal important. We have no experience with stemmed cup.
Dear all,
I understand that BS cage can be an option for acetabular reconstruction in severe bone defect, it is well documented in literature that it works in old patients with low functional requests but in young patients long term results are poor. In my experience in severe bone defects Paprosky 3a-b or pelvic disjunction an iliac screw modular cup is reliable safe and it is a relatively straight procedure. I really do suggest in case of acetabular cup revision in severe bone defect this method of reconstruction.
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