An experimental piglet model induces avascular necrosis (AVN)
and deformation of the femoral head but its secondary effects on
the developing acetabulum have not been studied. The aim of this
study was to assess the development of secondary acetabular deformation
following femoral head ischemia. Intracapsular circumferential ligation at the base of the femoral
neck and sectioning of the ligamentum teres were performed in three
week old piglets. MRI was then used for qualitative and quantitative
studies of the acetabula in operated and non-operated hips in eight
piglets from 48 hours to eight weeks post-surgery. Specimen photographs and
histological sections of the acetabula were done at the end of the
study. Objectives
Methods
We determined the frequency, rate and extent
of development of scoliosis (coronal plane deformity) in wheelchair-dependent
patients with Duchenne muscular dystrophy (DMD) who were not receiving
steroid treatment. We also assessed kyphosis and lordosis (sagittal
plane deformity). The extent of scoliosis was assessed on sitting anteroposterior
(AP) spinal radiographs in 88 consecutive non-ambulatory patients
with DMD. Radiographs were studied from the time the patients became
wheelchair-dependent until the time of spinal fusion, or the latest assessment
if surgery was not undertaken. Progression was estimated using a
longitudinal mixed-model regression analysis to handle repeated
measurements. Scoliosis ≥ 10° occurred in 85 of 88 patients (97%), ≥ 20° in
78 of 88 (89%) and ≥ 30° in 66 of 88 patients (75%). The fitted
longitudinal model revealed that time in a wheelchair was a highly
significant predictor of the magnitude of the curve, independent
of the age of the patient (p <
0.001). Scoliosis developed in
virtually all DMD patients not receiving steroids once they became
wheelchair-dependent, and the degree of deformity deteriorated over
time. In general, scoliosis increased at a constant rate, beginning
at the time of wheelchair-dependency (p <
0.001). In some there
was no scoliosis for as long as three years after dependency, but
scoliosis then developed and increased at a constant rate. Some
patients showed a rapid increase in the rate of progression of the
curve after a few years – the clinical phenomenon of a rapidly collapsing
curve over a few months. A sagittal plane kyphotic deformity was seen in 37 of 60 patients
(62%) with appropriate radiographs, with 23 (38%) showing lumbar
lordosis (16 (27%) abnormal and seven (11%) normal). This study provides a baseline to assess the effects of steroids
and other forms of treatment on the natural history of scoliosis
in patients with DMD, and an approach to assessing spinal deformity
in the coronal and sagittal planes in wheelchair-dependent patients
with other neuromuscular disorders. Cite this article:
