Surface hip replacement (SHR) is generally used
in younger, active patients as an alternative conventional total
hip replacement in part because of the ability to preserve femoral
bone. This major benefit of surface replacement will only hold true
if revision procedures of SHRs are found to provide good clinical
results. A retrospective review of SHR revisions between 2007 and 2012
was presented, and the type of revision and aetiologies were recorded.
There were 55 SHR revisions, of which 27 were in women. At a mean
follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris
hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical
reasons, nine for impingement, 13 for metallosis, nine for unexplained
pain and one for sepsis. Of the type of revision surgery performed,
14 were femoral-only revisions; four were acetabular-only revisions,
and 37 were complete revisions. We did not find that clinical scores were significantly different
between gender or different types of revisions. However, the mean
post-operative HHS was significantly lower in patients revised for
unexplained pain compared with patients revised for mechanical reasons
(86.9 (66 to 100) Based on the overall clinical results, we believe that revision
of SHR can have good or excellent results and warrants a continued
use of the procedure in selected patients. Close monitoring of these
patients facilitates early intervention, as we believe that tissue
damage may be related to the duration of an ongoing problem. There
should be a low threshold to revise a surface replacement if there
is component malposition, rising metal ion levels, or evidence of
soft-tissue abnormalities. Cite this article:
It has been proposed that a major advantage of surface replacement is that it is easy to revise and that the outcome of such revisions is good. This seems logical as the femoral head can easily be removed, the acetabular component can be cut out and a primary hip replacement can be inserted. Indeed a number of studies have shown good outcome following revision, particularly for femoral neck fracture. When we initially reviewed the results of our revisions we found that the operations were straight forward and the results were good provided the reasons for revision were neck fractures, loosening, infection and causes other than soft tissue reactions. When the reason for revision was soft tissue reaction, otherwise known as pseudotumour, the outcome was unsatisfactory with poor hip scores, and high rates of complications, revisions and recurrences. These were generally a manifestation of the soft tissue damage caused by the pseudotumours. We therefor recommended that early revisions should be considered with soft tissue reaction. By undertaking revisions earlier we have found that the results have improved but there are still cases with poor outcomes.
Surface replacement of the hip has become established as an alternative treatment to total hip replacement in the younger, active, male patient. By the very nature of preserving the femoral head and neck, there may be failures due to femoral neck fracture and femoral component loosening. Additionally, revisions of hip resurfacing for acetabular loosening may be necessary. Other scientific papers have described problems that may arise as a result of the metal-on-metal bearing either due to excess metal production or an immunologic-mediated reaction to the metal debris. Grammatopolous et al. describe poor results of revisions of surface replacements due to massive tissue destruction at the time of revision surgery, persistent pain, and swelling. In my experience with hip resurfacing, this complication is extremely rare. In my series of 925 resurfacings with a minimum of 2 year follow up, 12 revisions (1.3%) have been performed. Of these revisions, only 3 (0.3%) were for complications related to the metal-on-metal bearing; 2 for edge-loading and excess metal production, and 1 for metal hypersensitivity. None of the revision cases have had abductor destruction, or nerve/vascular involvement. Reconstruction of the joint was carried out with standard and revision components; post-operative function of these patients has been comparable to that of a primary total hip replacement. With careful monitoring of the post-operative resurfacing patient, problems can be identified early and
