We undertook a retrospective comparative study
of all patients with an unstable slipped capital femoral epiphysis presenting
to a single centre between 1998 and 2011. There were 45 patients
(46 hips; mean age 12.6 years; 9 to 14); 16 hips underwent intracapsular
cuneiform osteotomy and 30 underwent pinning in situ,
with varying degrees of serendipitous reduction. No patient in the
osteotomy group was lost to follow-up, which was undertaken at a
mean of 28 months (11 to 48); four patients in the pinning in
situ group were lost to follow-up, which occurred at a
mean of 30 months (10 to 50). Avascular necrosis (AVN) occurred
in four hips (25%) following osteotomy and in 11 (42%) following
pinning in situ. AVN was not seen in five hips
for which osteotomy was undertaken >
13 days after presentation.
AVN occurred in four of ten (40%) hips undergoing emergency pinning in
situ, compared with four of 15 (47%) undergoing non-emergency
pinning. The rate of AVN was 67% (four of six) in those undergoing
pinning on the second or third day after presentation.
Pinning in situ following complete reduction
led to AVN in four out of five cases (80%). In comparison, pinning in situ following
incomplete reduction led to AVN in 7 of 21 cases (33%). The rate
of development of AVN was significantly higher following pinning in
situ with complete reduction than following intracapsular
osteotomy (p = 0.048). Complete reduction was more frequent in those
treated by emergency pinning and was strongly associated with AVN
(p = 0.005).
Non-emergency intracapsular osteotomy may have a protective effect
on the epiphyseal vasculature and should be undertaken with a delay
of at least two weeks. The place of emergency pinning in
situ in these patients needs to be re-evaluated, possibly
in favour of an emergency open procedure or delayed intracapsular
osteotomy. Non-emergency pinning in situ should
be undertaken after a delay of at least five days, with the greatest
risk at two and three days after presentation. Intracapsular osteotomy
should be undertaken after a delay of at least 14 days. In our experience,
closed epiphyseal reduction is harmful.
Cite this article: Bone Joint J 2015;97-B:412–19.
