Deformity of the femoral head following vascular infarct in piglets.
BACKGROUND
In Legg-Calvé-Perthes disease (LCPD), 4 major patterns (coxa plana, coxa magna, coxa vara, subluxation) of the femoral head are commonly observed. However, direct observation of pathological specimens is rarely possible. An animal model of LCPD may clarify the pathogenesis of femoral head deformity.


METHODS
In 26 piglets, we interrupted the vascular supply to the capital femoral epiphysis by cutting the ligamentum teres and ligating the femoral neck containing the epiphyseal artery. 6-7 piglets in each experimental group were killed at early (2 and 4 weeks: P2 and P4), intermediate (12 weeks: P12), and late (20 weeks: P20) periods. We examined the extracted femoral heads macroscopically and radiographically.


RESULTS
The mean decrease in epiphyseal height was 1.5 mm, 4.1 mm, 5.0 mm, and 7.5 mm in P2, P4, P12 and P20, respectively (rs = 0.76, p = 0.002). The mean increase of diameter was 4.1 mm, 6.9 mm, and 6.8 mm in P4, P12 and P20, respectively. Decrease of the articulotrochanteric distance was mild in P2 and P4, and severe in P12 and P20. Subluxation of the femoral head was observed only in P12 and P20 piglets.


CONCLUSIONS
The piglet model of LCPD was useful in the early stage of devascularization for investigation of the developmental pattern of femoral head deformity. However, when the piglets had grown to 20 weeks old or more--that is, to full skeletal maturity--the femoral head and acetabulum showed severe deformities that were most likely caused by heavy body weight.
Department of Orthopedics, Chonnam National University Hospital, Hakdong 8, Kwangju, Korea. smrowe@chonnam.ac.kr
Sung Man
SM
Rowe
Jae Joon
JJ
Lee
Jae Yoon
JY
Chung
Eun Sun
ES
Moon
Eun Kyoo
EK
Song
Hyoung Yeon
HY
Seo
D000077:Acetabulum / Q000473:pathology; D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D005270:Femur Head / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology*; D007873:Legg-Calve-Perthes Disease / Q000209:etiology / Q000473:pathology*; D011859:Radiography; D013552:Swine