Correlation between reduction quality of femoral neck fracture and femoral head necrosis evaluated by three-dimensional measurement method / 中国组织工程研究

ABSTRACT

BACKGROUND:Reduction quality is essential for the healing and function of limb. Traditional X-ray and CT scans have some limitationsin quantitatively and visualy observing the reduction quality of the remnant fracture in three-dimensional displacements. Mimics have advantages in bone rapid modeling and three-dimensional measurement, which offers the chance in quantifying the reduction quality of the displacement in three-dimensional methods. OBJECTIVE:To measure residual displacement in femoral neck fracture patients with satisfactory reduction by using three-dimensional measurement method, and to evaluate the association between residual displacement and femoral head necrosis. METHODS:We enroled 141 patients with femoral neck fracture, who were treated in the Third Department of Joint, Affiliated Hospital of Logistics University of People’s Armed Police Force from January 2012 to December 2013. Al patients were divided into undisplaced fracture group (n=44; Garden1&2) and displaced fracture group (n=97; Garden3&4). Based on DICOM data of CT files, three-dimensional models were constructed in each patient. Three parameters were measured displacement of femoral head’s center, fossa capitis femoris and rotational displacement. Femoral head necrosis was folowed up. The correlation between residual displacement and femoral head necrosis was explored. RESULTS AND CONCLUSION:(1) The duration of folow-up in those patients ranged from 25 to 43 months. Femoral head necrosis occurred in 7 cases from the undisplaced fracture group and 21 cases from the displaced fracture group. (2) The three parameters (displacement of femoral head’s center, fossa capitis femoris and rotational displacement) were respectively (7.44±2.84) mm, (11.75±4.12) mm and (17.68±8.99)° in the undisplaced group, and (6.51±3.75) mm, (9.34±5.27) mm and (14.67±7.43)° in the displaced group. Except displacement of femoral head’s center, significant differences in the other two parameters were detected between the two groups (P< 0.05). (3) These findings suggest that poor reduction quality is the main factor causing femoral head necrosis. X ray is insufficient to describe the spatial shift and the angle, and has limitations in assessing the reductionquality of femoral neck fracture. Three-dimensional measurement has certain advantages to assess quality of fracture reduction.