postop cup migration in a RA osteoporotic patient

immediate postop

after postop mobilisation

This X-ray was send to me for an opinion. The initial X-rays were fine execpt for  some medialisation which in nonporotic bone would hav been fine.. On mobilising the patient complained of pain and the X-ray revealed the above.  It appears that the cup has migrated superiomedially suggesting a anterior column deficiency, but if the ilioischial line is traced up there appears to be a break sugesting posterior column breach.  Is it a T fracture.

   

First of all one needs Judet views and a ct to confirm the same. The options on table should include acetabular plates if the posterior column is compromised. A birch schnider cage if the posterior column is breached .if only the anterior column is breached one  could get away with a primary cup or a ganZ  cage and a cemented cup

Any comments or advise

 Our window for revision was 5 weeks later as the patient got chicken pox and had to postpone the revision  which increased the risks for bleeding dur to callus as well as reduced thr chances for  reduction of the T fracture  and plating. she also has a low pulmonary reserve and gross osteoporoisis. At revision we found a rotated maluniting posterior column a central/floor  defect. We elected to accept the deformity and bridge the defect with a BS cage with the inferior flange modified to a hook on table adding strength froM the tear drop( hope the flange does not break)  and cemented the cup and stem.  the stem is definitely in varus and the cementation could have been better . i do hope for a 10 yrs survival or more as she is low demand. we have started her on PTH  and VIT D.

 As a word of caution, beware of the severely porotic RA patient. using an uncemented cup is fine( if good bone stock is available) but watch out for fractures intra-op and may be postop. a cemented cup protected by a ganz cage or an antiprotrusio cage  could avoid a surgeons nightmare.