Evaluation of medial acetabular wall bone stock in patients with developmental dysplasia of the hip using a helical computed tomography multiplanar reconstruction technique.
BACKGROUND
The technique of medialization has been used to reconstruct acetabula at the level of true acetabula in total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Appreciation of the bone stock in the medial acetabular wall is significant for making an optimal acetabular reconstruction plan and avoiding complications.


OBJECTIVE
To evaluate the bone stock of the medial acetabular wall and its relation to the degree of subluxation in patients with DDH using computed tomography (CT).


METHODS
Helical CT scans of 27 hips were obtained from 21 patients with osteoarthritis secondary to DDH who were scheduled for total hip arthroplasty. Eleven hips belonged to Crowe class I, while 16 hips belonged to Crowe class II/III. The raw CT data were reprocessed in various planes by scrolling multiplanar reformation (MPR). Acetabular opening, depth, and medial bone stock, as indicated by the minimum thickness of the medial acetabular wall, were measured in the transverse reformed MPR plane.


RESULTS
The minimum thicknesses of the medial acetabular wall in Crowe-I and Crowe-II/III hips were 3.8+/-2.1 mm and 7.1+/-3.1 mm, respectively, with statistically significant differences between the groups (P<0.05). Furthermore, the bone stock in the medial acetabular wall correlated with the degree of subluxation (R=0.69) and the acetabular depth (R= ;- ;0.71).


CONCLUSIONS
There was significantly more bone stock in the medial acetabular wall in patients with higher-degree subluxation than there was in the less-severe class. This difference should be taken into consideration when reconstructing acetabula in THA in patients with DDH using the technique of medialization.
Liu
Rui Yu
RY
Department of Orthopedic Surgery, Second Hospital Affiliated to the Medical College of Xi'an Jiaotong University, Xi'an Shaanxi, PR China. liuryu@126.com
Wang
Kun Zheng
KZ
Wang
Chun Sheng
CS
Dang
Xiao Qian
XQ
Tong
Zhi Qin
ZQ
D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D005260:Female; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D018709:Statistics, Nonparametric; D036542:Tomography, Spiral Computed