This study analysed the clinical and radiological outcome of
anatomical reduction of a moderate or severe stable slipped capital
femoral epiphysis (SCFE) treated by subcapital osteotomy (a modified
Dunn osteotomy) through the surgical approach described by Ganz. We prospectively studied 31 patients (32 hips; 16 females and
five males; mean age 14.3 years) with SCFE. On the Southwick classification,
ten were of moderate severity (head-shaft angle >
30° to 60°) and
22 were severe (head-shaft angle >
60°). Each underwent open reduction
and internal fixation using an intracapsular osteotomy through the
physeal growth plate after safe surgical hip dislocation. Unlike
the conventional procedure, 25 hips did not need an osteotomy of
the apophysis of the great trochanter and were managed using an
extended retinacular posterior flap. Aims
Patients and Methods
We undertook a retrospective analysis of 306
procedures on 233 patients, with a mean age of 12 years (1 to 21),
in order to evaluate the use of somatosensory evoked potential (SSEP)
monitoring for the early detection of nerve compromise during external
fixation procedures for limb lengthening and correction of deformity.
Significant SSEP changes were identified during 58 procedures (19%).
In 32 instances (10.5%) the changes were transient, and resolved
once the surgical cause had been removed. The remaining 26 (8.5%)
were analysed in two groups, depending on whether or not corrective
action had been performed in response to critical changes in the
SSEP recordings. In 16 cases in which no corrective action was taken,
13 (81.2%, 4.2% overall) developed a post-operative neurological
deficit, six of which were permanent and seven temporary, persisting
for five to 18 months. In the ten procedures in which corrective
action was taken, four patients (40%, 1.3% overall) had a temporary
(one to eight months) post-operative neuropathy and six had no deficit. After appropriate intervention in response to SSEP changes, the
incidence and severity of neurological deficits were significantly
reduced, with no cases of permanent neuropathy. SSEP monitoring
showed 100% sensitivity and 91% specificity for the detection of
nerve injury during external fixation. It is an excellent diagnostic
technique for identifying nerve lesions when they are still highly
reversible.
