Does the size of the femoral head correlate with the incidence of avascular necrosis of the proximal femoral epiphysis in children with developmental dysplasia of the hip treated by closed reduction?

Abstract

Purpose The purpose of this study was to identify if any correlation between size of the proximal femoral epiphysis and avascular necrosis (AVN) exists. Methods We retrospectively reviewed 111 patients with developmental dysplasia of the hip treated by closed reduction (124 hips). The diameter and height of both femoral head and ossific nucleus were assessed on preoperative MRI. Results The diameter and the height of the femoral head as well as of the ossific nucleus of the contralateral side were significantly greater than the dislocated side. AVN occurred in 21 (16.9%) out of 124 hips. The rate of AVN gradually decreased with age: 30.0% at six to 12 months, 18.2% at 12 to 18 months and 3.7% at 18 to 24 months. Spearman correlation analysis showed that age is negatively correlated with the incidence of AVN (r = -0.274; p = 0.002) and the diameter of the femoral head has a significantly negative association with the incidence of AVN (r = -0.287; p = 0.001). No significant association was observed between the incidence of AVN and height of the femoral head or size of the ossific nucleus. Hips with AVN were significantly smaller than hips without AVN. Conclusions The size of both the femoral head and the ossific nucleus increase with age although the dislocated femoral head is smaller compared with the contralateral side. The diameter of the femoral head and not the size of the ossific nucleus negatively correlate with the risk of AVN, with a bigger femoral head showing lower risk of AVN. Level of evidence III

Developmental retardation of femoral head size and femoral head ossification in mild and severe developmental dysplasia of the hip in infants: a preliminary cross-sectional study based on ultrasound images

“…Persistent lateral hip subluxation and dislocation result in a shallow acetabulum and a mismatched femoral head. A smaller femoral head and delayed appearance of the ossific nucleus in radiographic DDH were also found in the study of Wu et al (22) and Sugawara et al (23). More importantly, a smaller femoral head was significantly associated with the incidence of avascular necrosis (22).…”

Evaluation of avascular necrosis risk factors after closed reduction for developmental dysplasia of the hip before walking age

“…Wu et al . [21] measured the ossific nucleus size on MRI of the patients they applied closed reduction and reported that ossific nucleus size was not related to AVN of the femoral head. Chen et al .…”

Does the vascular development of the femoral head correlate with the incidence of avascular necrosis of the proximal femoral epiphysis in children with developmental dysplasia of the hip treated by closed reduction?

“…Our studies have also showed that the incidence of poor perfusion of the femoral head on the dislocated side was significantly higher than that at contralateral side. 22 In all, 61.5% of vascular perfusion of the femoral head was partially or globally decreased on the dislocated side in patients with DDH after CR, but not decreased at the contralateral side. Tiderius et al 15 reported that pMRI was used to evaluate the perfusion changes of the femoral head after CR in 27 children (28 hips) with DDH, and the results showed that 20 hips (71.4%) showed focal, asymmetric and global decreased of perfusion of the femoral head after CR on the dislocated side.…”

“…Our previous study has also shown that the development of the femoral head on the dislocated side in patients with DDH is significantly poorer than that at the contralateral side. 22 This may be related to the lack of mutual stress stimulation between the dislocated femoral head and acetabulum, the poor development of the femoral head and the poor development of the vascular.…”

“…Our previous studies have also shown that poor development of the femoral head is a risk factor of AVN in patients with DDH after CR. 22 , 23 Thus, vascular immaturity of the femoral head before CR is an intrinsic factor in the occurence of AVN after CR. This may also explain why the occurrence of AVN after DDH surgery is difficult to avoid completely regardless of the therapeutic measures taken.…”