Page 109 - Slipped Capital Femoral Epiphysis Pathogenetic and Clinical aspects

Eighty-eight per cent of our study group felt that an acute, unstable SCFE was an
urgent situation and definitive management should take place within 24 h of the
event. These figures are probably the same as in the POSNA study [6] in which
only 12% of surgeons felt that the case could be ‘added to the elective schedule’.
Sixty-six per cent of respondents stated that they do not reposition the slip but
it may be that in some cases the administration of a general anaesthetic and
the process of positioning the patient on the operating table actually result in
an improvement of the relationship between the epiphysis and the metaphysis.
The free text sections of the questionnaire provoked considerable comment
regarding the concept of ‘gentle repositioning’. From the literature, there appears
to be a ‘cut-off’ point around 24 hours [11–13] after which the incidence of AVN
is likely to rise. In the study by Peterson [11], if manipulation and fixation occurred
within 24 hours of presentation, the AVN rate was 7% but this increased to 20% if
similar management occurred after 24 hours. The major source of blood supply
to the epiphysis is through the posterior–superior retinacular vessels. Bone scans
on admission demonstrate the relationship between instability of the physis and
abnormal blood supply to the head suggesting that the most likely cause of AVN
lies in the initial displacement caused by the injury [14,15] An increasing suggestion
is found in the literature that decompression of the hip joint by aspiration [16] or 6 with a more formal arthrotomy [17,18] reduces the rate of AVN following displaced
femoral neck fractures in the paediatric population. No published evidence supports this approach in the management of the acute, unstable SCFE and yet 29% of surgeons in this study do decompress the joint. A similar extrapolation of principles was noted in the POSNA study in which 36% of respondents decompress the capsule.
In keeping with the literature, which demonstrates a tendency to operate percutaneously and use one screw fixation [3,4,12,19–24], most of our respondents (79%) used a single screw. Interestingly, the use of a second screw was significantly higher in those surgeons with more experience. In the POSNA study [6], a greater percentage used two screws (40%) but no comment is made as to whether this was more likely to occur if the surgeon was more experienced or not.
Although Mooney et al. [6] suggest that many European centers favor prophylactic pinning of the normal side, it was only offered routinely by 6% of UK surgeons and 15% of Dutch surgeons, although more senior surgeons were more likely to perform prophylactic fixation than their junior colleagues. Thus, overall, this study
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