THE ANATOMICAL RECORD 297:643–649 (2014)
Three-Dimensional Computed Tomography Reconstruction Measurements of Acetabulum in Chinese Adults HECHENG MA,1 YINGYING HAN,2 QIWEI YANG,2 YUBAO GONG,1 SHUANG HAO,3 YOUQIONG LI,4 AND JIANGUO LIU2* 1 Department of Orthopaedics, The First Hospital of Jilin University, Changchun, Jilin 130021, China 2 China-Japan Union Hospital of Jilin University, Changchun, Jilin 130021, China 3 The Second Hospital of Jilin University, Changchun, Jilin 130021, China 4 Department of Anatomy, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin 130021, China
ABSTRACT The present study was designed to define the morphological dimensions of the acetabulum in normal Chinese adults and to statistically compare these data with the available data worldwide. This information is important for the diagnosis of dysplasia and treatment of total hip arthroplasty. In this study, the gender and bilateral differences were evaluated. One-hundred CT scans of patients were retrospectively studied. These individuals showed no signs of developmental disturbances in either of the hip joints. Thirty-five morphometric parameters of the acetabulum were measured. The size of acetabulum was evaluated by the acetabular perimeter, anteroposterior diameter, vertical diameter, the depth and width of fossa ovalis in both transaxial and coronal plane. The parameters of acetabular orientation were the acetabular angle, anterior center edge angle, neck shaft angle, acetabular anteversion, and abduction angle. The coverage of acetabulum was examined as the, acetabular head index, center edge angle, the distance between the femoral head, and acetabulum. Gender and bilateral differences were analyzed for each parameter, and compared with available worldwide data. The results showed statistically significant differences between the Chinese genders and also between the Chinese and other human races in some parameters. In conclusion, gender, bilateral and racial differences exist in the morphology of acetabulum. The data may be helpful for the design of total hip arthroplasty for the Chinese population. Anat Rec, 297:643–649, C 2014 Wiley Periodicals, Inc. 2014. V
Key words: acetabulum; computed tomography; hip dysplasia; Chinese; gender; race; bilateral
Developmental dysplasia of the hip (DDH), a serious disease of the hip, is closely associated with morphological abnormalities of the acetabulum, particularly acetabular size, width, depth, orientation and the coverage of a femoral head. It is characterized by an anteverted shallow acetabulum with deficient anterior, superior or lateral coverage of the femoral head (Murphy et al., 1990). C 2014 WILEY PERIODICALS, INC. V
*Correspondence to: Jianguo Liu, Department of Orthopaedics, The First Hospital of Jilin University, Changchun, Jilin 130021, China. E-mail: [email protected] Received 13 June 2013; Accepted 23 December 2013. DOI 10.1002/ar.22885 Published online 11 February 2014 in Wiley Online Library (wileyonlinelibrary.com).
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TABLE 1. Morphometric measurements performed on 100 people acetabulum (No. 1–27 are measured on CT workstation, while No. 28–32 are measured on Efilm workstation) No. 1 2 3 4
Name AP AWt AWc
Figure
Measurement
1 1 1 2
Acetabular perimeter The width between the most anterior and posterior point in transaxial plane The width between the highest and low point in coronal plane The distance between the anterior acetabulum and the femoral head in transaxial plane The distance between the posterior acetabulum and the femoral head in transaxial plane The distance between the lateral margin of acetabulum and the femoral head in coronal plane The distance between highest point of acetabulum and the femoral head in coronal plane The least thickness of the bone of acetabulum in transaxial plane The width of fossa ovalis in transaxial plane The depth of fossa ovalis in transaxial plane The least thickness of the bone of acetabulum in coronal plane The width of fossa ovalis in coronal plane The depth of fossa ovalis in coronal plane The area that is enclosed by acetabulum and line between the anterior and posterior point The area that is enclosed by acetabulum and the femoral head The area that is enclosed by the line between anterior and posterior point and the femoral head The angle of the horizon and a line through the most superior point of the acetabular joint surface and anterior rim of the acetabulum The angle by the horizontal axis and a line running through the center point and the anterior point of acetabular in transaxial plane The angle by the horizontal axis a line running through the center point and the posterior point of acetabular in transaxial plane The angle by the vertical axis and a line running through the center point and the high lateral margin acetabular in coronal plane The angle by the vertical axis and a line running through the center point and the low lateral margin acetabular in coronal plane The angle between a line combining the anterior and posterior margins of the acetabulum and a sagittal line in transaxial plane The angle between a line combining the high and low margins of the acetabulum and the vertical axis line in coronal plane The angle between a line through the anterior margins of acetabulum and the posterior margin of fossa ovalis and the coronal line in the transaxial plane The angle between a line through the posterior of acetabulum and the posterior margin of fossa ovalis and the coronal line in the transaxial plane The angle between a line through the high margin of acetabulum and fossa ovalis and the vertical axis line in the coronal plane The angle between a line through the low margin of acetabulum and the high margin of fossa ovalis and the vertical axis line in the coronal plane The depth of acetabulum in coronal plane The depth of acetabulum in transaxial plane The distance of the highest margin of acetabulum to the horizontal line through the lateral margin of acetabulum in coronal plane The distance of the two vertical axis lines that through either innermost of femoral head or lateral margin of acetabulum in coronal plane The diameter of the femoral head The angle of the long femoral shaft and the head Coverage rate is a rate of No.15/No.14 Acetabulum head index is a rate of No. 31/No. 32
5
2
6
7
7
7
8 9 10 11 12 13 14
2 2 2 7 7 7 3
15 16
3 3
17
ACE
1
18
AnCE
4
19
PCE
4
20
CE
8
21
ICE
8
22
AcetAV
5
23
AcetAD
9
24
AnAA
6
25
PAA
6
26
AA
10
27
IAA
10
28 29 30
ADc ADt
9 5 7
31 32 33 34 35
11 NSA CR AHI
11 12
The key to diagnosis of acetabular dysplasia lies in the accurate evaluation of quantitative parameters of the acetabulum. Furthermore, total hip arthroplasty (THA), performed worldwide, has resulted in favorable clinical outcomes (Faldini et al., 2011). However, a malpositioned acetabular prosthesis during THA can result in dislocation, pelvic osteolysis, limited range of motion, polyethylene wear, and component migration (Parvizi et al., 2007). To avoid THA complications, the prosthesis must be placed in the right position (Biedermann et al., 2005) and the
prosthesis should well match the anatomy of the individual patient. Thus having accurate morphology of the acetabulum improves the clinical outcomes of THA. Because there are ethnicity differences in the morphology of the acetabulum, different surgical guides have been developed for THA (Lewinnek et al., 1978). Presently, however, there are few studies concerning the morphology and morphometrics of acetabular anatomy in normal Chinese adults. In this paper, acetabulum CT scans were measured, retrospectively, from 100 hundred individuals who
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
645
Fig. 1. 1–12 Schematic drawings of measurements 1–33 (the horizontal line is in parallel with the line between the right and left center point of the head of femur, the sagittal line is perpend.
showed no signs of developmental dysplasia in their hips. The purpose of this study was to show the morphology and morphometrics of Chinese acetabulum and statistically compare them with the available data from other ethnic groups. The second purpose of this study was to determine the variations that occur in normal hips, and in any underlying differences concerning their gender, bilateral sides and races.
MATERIALS AND METHODS
Methods All patients underwent a routine scan on a CT scanner (Toshiba Aquilion One). The patients were positioned with their legs fully extended and feet stabilized in a neutral position. With the following parameters: 140 kV, 250 mA, and standard algorithm, Heli-cal 0.5-mm CT sections were obtained. The data were transferred to a diagnostic workstation and reconstructed with the ViteaFx software. Images in the transaxial, coronal, and sagittal planes were routinely reformatted and measured.
Patients
CT Evaluation
Ethics and scientific committee approvals were obtained from our institution for this study and informed consents were obtained from all participants. This retrospective study was performed at the Jilin University Hospital. Using the hospital’s archiving system, information was obtained on hip CT scans. In this series, individuals with signs of osteoarthrosis, arthritis, congenital, or developmental structural changes were excluded. Ultimately, 100 patients (54 females and 46 males), presenting no signs of developmental dysplasia in either hip, were investigated. The mean age of the female was 61.6 years (range, 24–88 years), with the mean height being 161 cm (range, 152– 181 cm). The mean age of the male was 51.7 years (range, 19–76 years), with the mean height being 173 cm (range, 155–189 cm). Both sides of their acetabulums had been CT-scanned and three-dimensionally reconstructed, and no abnormalities were found.
The measurement was carried out on the workstation. A complete list of all measurements performed is given in Table 1. The figures (Fig. 1) also illustrate most of these measurements.
Statistical Analysis Distribution of the values was estimated by descriptive statistical analyses. The parameters including the sex and race differences were assessed using the two independent sample t test (SPSS17.0). P < 0.05 were considered statistically significant.
RESULTS A total of 33 measurements were performed on each acetabulum. The orientation of acetabulum were the
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TABLE 2. Results of morphometric measurements on 100 intact human people’s CT scan (distances are given in mm, except No. 28–32 given in cm, angles are given in degrees, the areas are given in mm2) Female
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Male
Left
Right
Left
Right
P0 value
P00 value
177.5 6 9.9 49.1 6 2.4 51.0 6 3.4 3.3 6 0.8 2.7 6 0.8 4.7 6 1.2 2.8 6 1.1 4.0 6 1.4 26.6 6 3.9 6.7 6 1.5 4.1 6 1.6 21.0 6 3.6 4.5 6 1.0 738.2 6 126.1 205.2 6 43.3 1657.9 6 237.8 29.1 6 5.7 31.2 6 8.5 11.7 6 5.9 34.6 6 6.6 63.4 6 5.3 21.6 6 5.6 50.4 6 3.9 80.4 6 6.9 22.8 6 6.3 9.0 6 5.9 111.9 6 5.8 1.8 6 0.2 2.3 6 0.3 0.3 6 0.2 3.8 6 0.3 4.3 6 0.3 126.7 6 3.6 28.0 6 4.9 88.0 6 7.3
179.4 6 10.4 49.4 6 2.4 49.3 6 2.5 3.2 6 0.8 2.5 6 0.9 5.4 6 1.3 2.8 6 1.1 3.6 6 1.1 25.6 6 3.3 6.5 6 1.4 3.8 6 1.1 20.7 6 4.3 4.4 6 1.0 710.2 6 109.7 187.0 6 41.2 1668.0 6 247.8 30.7 6 5.1 30.0 6 8.5 10.6 6 7.1 35.1 6 6.1 63.8 6 6.3 21.1 6 6.0 51.3 6 3.8 79.6 6 6.8 25.4 6 5.9 9.7 6 5.8 111.2 6 5.6 1.8 6 0.2 2.3 6 0.3 0.3 6 0.2 3.7 6 0.3 4.3 6 0.3 126.2 6 3.8 26.4 6 4.8 86.6 6 5.2
197.7 6 12.3 53.8 6 2.8 56.1 6 3.1 3.6 6 1.0 2.6 6 1.0 4.8 6 1.4 3.2 6 0.8 4.2 6 1.3 27.1 6 4.4 6.9 6 1.8 4.2 6 1.3 22.6 6 4.8 5.1 6 1.4 941.3 6 152.5 247.1 6 70.5 1605.6 6 251.7 27.9 6 6.3 30. 1 6 7.1 11.5 6 6.3 37.0 6 5.7 63.0 6 4.3 20.4 6 5.5 51.3 6 3.7 77.1 6 6.9 24.2 6 5.5 7.7 6 6.1 110.3 6 6.3 2.1 6 0.2 2.6 6 0.3 0.5 6 0.2 4.2 6 0.3 4.8 6 0.3 127.6 6 3.8 26.5 6 6.7 87.5 6 4.8
200.8 6 10.8 54.4 6 2.6 56.3 6 2.7 3.5 6 1.1 2.7 6 0.9 4.9 6 1.4 3.4 6 1.0 4.1 6 1.4 26.5 6 4.2 6.7 6 1.7 4.2 6 1.2 22.5 6 5.0 5.0 6 1.4 919.0 6 148.3 221.8 6 57.4 1615.8 6 255.8 28.3 6 6.5 30.3 6 8.3 11.7 6 6.7 38.0 6 8.9 63.5 6 7.1 20.3 6 5.8 52.1 6 4.8 75.6 6 6.4 26.9 6 5.4 8.2 6 6.8 110.7 6 6.5 2.1 6 0.3 2.5 6 0.3 0.4 6 0.2 4.3 6 0.4 5.0 6 0.5 126.0 6 3.8 24.4 6 5.7 87.1 6 5.4
P < 0.001 P < 0.001 P < 0.001 P < 0.01 P > 0.05 P > 0.05 P < 0.05 P < 0.01 P > 0.05 P > 0.05 P > 0.05 P < 0.01 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P < 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.001 P > 0.05 P < 0.05 P > 0.05 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P > 0.05 P < 0.05 P > 0.05
P < 0.01 P > 0.05 P > 0.05 P < 0.01 P > 0.05 P < 0.01 P > 0.05 P > 0.05 P < 0.01 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P < 0.001 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P < 0.001 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.01 P > 0.05
P0 value: male versus female hip; P00 value: left versus right side.
lateral, inferior, anterior, and posterior AA angle and CE angles, ACE angle, AcetAV angle, AcetAD angle, neck shaft angle. The size of acetabulum was assessed by the diameter, the depth, and width of the acetabulum and fossa ovalis both in transaxial and coronal planes. The coverage of the acetabulum were interpreted by the CE angle, CR, AHI, the distance between the head of femur of acetabulum. The detailed results are present in Table 2. The comparisons of the mean parameters in female with those in male and the bilateral parameters are shown in Table 2.
clinical outcomes in treating the acetabular dysplasia (Faldini et al., 2011). A malpositioned acetabular prosthesis and an unfit prosthesis during THA may result in dislocation, pelvic osteolysis, limited range of motion, polyethylene wear, and component migration (Parvizi et al., 2007). To avoid these complications, an understanding of the morphology of acetabulum in the individual patient is important for a successful clinical outcome from the surgery. In the present study, the normal, nondiseased, acetabular morphology in Chinese population is described.
The Orientation of Acetabulum DISCUSSION Computed tomography has proven to be a practical approach to assess acetabular deformity and acetabular morphology. An understanding of the normal range of acetabular morphometric parameters has been the key to distinguish acetabular deformity from normal anatomical variations (Chiron et al., 2012). However, the range of normal acetabular variations may differ between races and genders (Nicholls et al., 2011). While total hip arthroplasty (THA) has generally favorable
In the present study, the orientation of the acetabulum was described by the acetabular angle, anterior center-edge angle, neck shaft angle, acetabular anteversion, and abduction angle. The published values of the acetabular orientation by ethnic groups are shown in Table 3. Acetabular angle, originally described by Sharp (1961), is considered as the most important indicator in the diagnosis of dysplasia of the acetabulum. The comparisons shown in Table 3 provide clear evidence that variations exist between different races. The AA angle
Lavy et al. (2003) Jeremic´ et al. (2011) Stem et al. (2006) Lequesne et al. (2004) Tuck et al. (2005) Nelitz et al. (1999) Murtha et al. (2008) – – – – – – – 132.83 6 4.37 – 128 6 1.7 130 6 3.3 – 137.3 6 9.0 55.5 6 10.4 – – – –
– – – 19.3 6 10.8
– – 39.0 6 4.0 – – – 57.1 6 9.1 – –
– – 23.0 6 5.0 – – – 24.1 6 9.2
–
– –
36.65 6 4.61 35.66 6 4.68 38.6 6 4.9 38.5 6 3.9 – 3.63 6 4.52 39.0 6 3.2 43.5 6 4.3 – Malawian Serbian American France British German American
L R Nigerian
36.2 6 2.8
12.34 6 7.5 15.8 6 8.72 – 9.0 6 6.0 – – – 35.60 6 4.70 35.47 6 4.11 36.9 6 4.0 37.5 6 3.6 –
– 39.0 6 3.2 41.8 6 3.4 Japanese
– 9.19 6 6.24 36.5 6 3.5 37.31 6 4.27 37.5 6 3.8 38.28 6 4.43 Korean South Asian
Finnish
Chinese
L R
– – 164
– – 565
– – 30 6 4
–
–
12.74 6 10 16.97 6 7.69 – 6.2 6 4.9 – – –
–
–
–
–
–
– – 44.4 6 6.5 17.9 6 6.3 –
– 11.68 6 6.0
– –
– –
– –
– –
– –
– –
Tallroth and Lepist€o (2006) Han et al. (1998) Fujii (2001), Umer et al. (2009), Fujii (2001), Minoda et al. (2006) Oladipo et al. (2010)
Zeng et al. (2011)
– – – – – – 39.5 6 3.62 40.2 6 3.03 – 41.2 6 3.98 42.2 6 3.87 – 18.1 6 5.55 16.0 6 5.74 17 6 6 17.6 6 4.8 0 18.1 6 5.55 23 6 7 – – 31 6 4
Male Female Male Female Male Female Male Female Male Female
Neck shaft angle Acetabular abduction angle Acetabular anteversion angle Anterior center-edge angle Acetabular angle
TABLE 3. Published values of the acetabular orientation by ethnic groups ( )
References
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
647
described in a Finnish population (Tallroth and Lepist€o, 2006) is in accordance with the present observations in the Chinese populations. It should be noted that there were significant gender differences in both populations. However, the AA angle of other races were much larger than that observed in the present study (P < 0.001), perhaps due in part to the different methods that were used in these measurements. Even though there were variations in the anatomical landmarks used in the measurements in different studies, all conclude that there were significant gender differences. The ACE angle is an effective measurement to show the superior–anterior coverage of the femoral head (Lequesne, 1961). Several studies of different races in Table 3 indicate that the results from the Chinese population differ from other races except for the Finnish populations. Some of these differences may be due to different methods being used (i.e., X-ray radiography and CT), however there were gender differences except in the Finnish population. AcetAV angle and AcetAD angle are two important angles to describe the orientation of the acetabulum (Anda et al., 1991; D’Lima et al., 2000). It is important during THA to place the prosthesis in the right position (Ghelman et al., 2009), or serious postoperative complications could occur (Minoda et al., 2006). A “safe zone” for the orientation of the acetabular component (abduction 40 6 10 , anteversion 20 6 5 ) has been recommended (Soong et al., 2004) to best avoid these complications. However, this “safe zone” does vary with age, gender, and race in acetabular orientation. The comparisons presented in Table 3 raise the intriguing possibility that acetabular anteversion in the American, Finnish, and Japanese populations are significantly larger in females than males, and this differs from the findings in Chinese population. Neither the southeast Chinese (Zeng et al., 2011) nor the present observation show any gender differences in the anteversion of acetabulum. Furthermore, the Chinese AcetAV angle was much larger than the Japanese, comparable with the AcetAV angle of the Americans and Finnish populations. As for the AcetAD angle, Zeng et al. (2011) reports that it is larger in southeast Chinese females than males (P < 0.001), which is inconsistent with the present findings. In addition, the AcetAV angle reported here differs from other races. No significant gender difference was found in both AcetAV angle and AcetAD angle and this differs from the results of others. It should be emphasized that it is the acetabular orientation that is important for the success of the THA procedure (Biedermann et al., 2005; Ghelman et al., 2009; Minoda et al., 2006; Lewinnek et al., 1978) and the parameters defined in the present study should help guide surgeons for procedures in the Chinese population. The femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk (Alonso et al., 2000; Gnudi et al., 2011). In a United Kingdom (UK) population (Tuck et al., 2005), the NSA in the female was significantly smaller than in the male, which is inconsistent with those measured in the present study. Tuck et al. (2005) found that the mean NSA was significantly smaller in those with vertebral fractures, but larger in those with distal forearm fractures (P 5 0.01), suggesting that femoral NSA is determinant of hip fracture risk in UK men (Tuck et al., 2011).
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MA ET AL.
TABLE 4. The published values of the acetabular size by ethnic groups AD (mm) Chinese
L R
Japanese British Austrian
AW (mm)
AP (mm)
Female
Male
Female
Male
Female
Male
17.5 6 1.68 19.4 6 2.21 9.2 6 0.5 14.4 6 0.2 10.2 6 2.7
19.4 6 2.21 19.3 6 2.48 8.9 6 0.5 14.4 6 0.4 11.5 6 2.6
51.4 6 2.07 51.4 6 2.38 – – 48.3 6 3.3
56.0 6 3.33 55.2 6 3.11 – – 49.5 6 2.3
–
–
– – 68.5 6 2.9
– – 65.9 6 5.2
–
–
47.8 6 2.3
56.3 6 2.6
147.5 6 6.4
170.6 6 7.9
Italian
Zeng et al. (2011) Yoshimura et al. (1998) Genser-Strobl and Sora (2005) Benazzi et al. (2008)
TABLE 5. The published values of the acetabular coverage by ethnic groups CE ( )
AHI (%)
South Asian Nigerian Malawian British Japanese Japanese
L R
Female
Male
Female
Male
References
89.0 6 6.0 46.0 6 5.7 48.0 6 4.7 84.8 6 5.0 81.6 6 5.0 80.6 6 6.4 81.7 6 4.6
87.0 6 5.0 48.0 6 0.3 47.0 6 0.5 85.5 6 5.1 82.3 6 5.2 81.1 6 5.0 88.5 6 6.6
34.57 6 6.78 33.98 6 6.09 33.17 6 6.80 34.3 6 7.5 30.4 6 5.4 27.9 6 6.5
36.28 6 6.44 34.80 6 6.99 32.43 6 7.74 34.0 6 7.5 31.7 6 5.5 29.5 6 5.9
Umer et al. (2009) Oladipo et al. (2010)
German
74.3 6 7.9
Several studies of different races in Table 3 indicate that all races share a similar NSA. The inferior, anterior, and posterior acetabular angles were also measured. These angles have not previously been measured and these values may provide additional data of great value for surgical procedures in the acetabulum (Peters et al., 2012; Pierchon et al., 1994; Yoshimine, 2006). There were, however, significant differences between female and male. Thus, taking all into consideration, these parameters describing the acetabular orientation give an evidence on the guide of THA on different race and genders.
The Size of Acetabulum The size of acetabulum is important for prosthetic design (Berry et al., 2005). And the published values of the acetabular orientation by ethnic groups are shown in Table 4.The depth of acetabulum (AD) is considered as a very important measurement for acetabular dysplasia and osteoarthritis (Lequesne et al., 2004; Yoshimura et al., 1998). There are gender differences in these parameters in Chinese and other races (Table 4). However, the AD found in the present study is larger than that reported for Japanese, British, and Austrian (Genser-Strobl and Sora, 2005; Yoshimura et al., 1998). Among the published value in Table 4, a significant difference exists in different races. Furthermore, differences exist between coronal and transaxial plane in our observation. The depth of acetabulum in the transaxial plane is much larger than that in the coronal plane. This means the acetabulum is not vertical. As for the width of acetabulum (AW), our result is similar to other published results on Chinese (Zeng et al., 2011), with a significant difference between female and male. However, the AW of Austrian (Genser-Strobl and Sora, 2005)
>25 23.5 6 7.8
Lavy et al. (2003) Chosa and Tajima (2003) Nelitz et al. (1999)
and Italian (Benazzi et al., 2008) much smaller than other results, including Chinese.
The Coverage of Acetabulum The acetabular head index (AHI) is classical used to assess femoral head coverage (Chosa and Tajima, 2003). A report of south Asian by Umer et al. (2009) showed the mean AHI is quite similar to ours with no gender difference. However, other researches in Table 5 about Nigerian, British, and German suggest much smaller than ours, especially the Nigerian. It is reasonable that the races lead to the different AHI. The center edge angle (CE angle), originally described by Wiberg and Frey (1939), is perhaps the most popular indicator estimated in most of the radiographic classifications, which evaluates the degree of lateral overage of the femoral head in the frontal plane (Ttinnts, 1976). Many authors have reported the CE angle of their own races, and race differences can be obviously seen from Table 5. There are significant gender differences in all races except two African countries Malawian and Nigeria. The CE angle of Japanese and German are much smaller than others. Taken all into consideration, the differences in the coverage of the acetabulum lead to different diagnosis of DDH and different surgery strategy. Furthermore, the distance between the femoral head and the acetabulum were also measured in anterior, superior, lateral, and posterior site of acetabulum. All these parameters clearly indicate the coverage of acetabulum. The coverage of acetabulum changed once DDH or acetabular fracture happened. So it is a very important morphological parameter to diagnosis the DDH and fracture. Interestingly, apart from the gender and racial difference, the bilateral difference has also been analyzed. According to the recent research, no bilateral differences
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
were found in all except Vandenbussche’s report (2008), which confirmed and quantified the asymmetry of the acetabular rim. It is the same with our observation. There are no significant differences in this common parameter of Chinese acetabulum. However, the new parameters that never conducted by others show a little difference, such as the acetabular perimeter, the distance between the acetabulum and the femur head shown in Table 2. A better understanding of the difference remains to be elucidated in more detail. In conclusion, new morphometric data on the hip joint specific for Chinese populations were raised in the present study and all the parameters defined should help guide surgeons for procedures in the Chinese population. A well understanding of the morphometry and morphology of acetabulum in the individual patient is important for a successful clinical outcome from the surgery. Secondly, there were significant gender and racial differences in most measurements.
ACKNOWLEDGEMENTS The authors are grateful to the department of radiology, China-Japan Friendship Hospital for achieving the measurement.
LITERATURE CITED Anda S, Terjesen T, Kvistad KA. 1991. Computed tomography measurements of the acetabulum in adult dysplastic hips: Which level is appropriate? Skeletal Radiol 20:267–271. Alonso CG, Curiel MD, Carranza FH, Cano RP, Perez AD. 2000. Femoral bone mineral density, neck-shaft angle and mean femoral neck width as predictors of hip fracture in men and women. Osteoporos Int 11:714–720. Benazzi S, Maestri C, Parisini S, Vecchi F, Gruppioni G. 2008. Sex assessment from the acetabular rim by means of image analysis. Forensic Sci Int 180:e51–e58. Berry DJ, von Knoch M, Schleck CD, Harmsen WS. 2005. Effect of femoral head diameter and operative approach on risk of dislocation after primary total hip arthroplasty. J Bone Joint Surg Am 87:2456–2463. Biedermann R, Tonin A, Krismer M, Rachbauer F, Eibl G, St€ ockl B. 2005. Reducing the risk of dislocation after total hip arthroplasty: The effect of orientation of the acetabular component. J Bone Joint Surg Br 87:762–769. Chiron P, Espie A, Reina N, Cavaignac E, Molinier F, Laffosse JM. 2012. Surgery for femoroacetabular impingement using a minimally invasive anterolateral approach: Analysis of 118 cases at 2.2-year follow-up. Orthop Traumatol Surg Res 98:30–38. Chosa E, Tajima N. 2003. Anterior acetabular head index of the hip on false-profile views. New index of anterior acetabular cover. J Bone Joint Surg Br 85:826–829. D’Lima DD, Urquhart AG, Buehler KO, Walker RH, Colwell CW Jr. 2000. The effect of the orientation of the acetabular and femoral components on the range of motion of the hip at different headneck ratios. J Bone Joint Surg Am 82:315–321. Faldini C, Miscione MT, Chehrassan M, Acri F, Pungetti C, d’Amato M, et al. 2011. Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: Results after 12-years follow-up. J Orthop Traumatol 12:213–218. Genser-Strobl B, Sora MC. 2005. Potential of P40 plastination for morphometric hip measurements. Surg Radiol Anat 27:147–151. Ghelman B, Kepler CK, Lyman S, Della Valle AG. 2009. CT outperforms radiography for determination of acetabular cup version after THA. Clin Orthop Relat Res 467:2362–2370. Gnudi S, Sitta E, Pignotti E. 2011. Prediction of incident hip fracture by femoral neck bone mineral density and neck-shaft angle:
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A 5-year longitudinal study in post-menopausal women. Br J Radiol 85:467–473. Lavy CB, Msamati BC, Igbigbi PS. 2003. Racial and gender variations in adult hip morphology. Int Orthop 27:331–333. Lequesne M, de Seze. 1961. False profile of the pelvis. A new radiographic incidence for the study of the hip. Its use in dysplasias and different coxopathies. Rev Rhum Mal Osteoartic 28:643–652. Lequesne M, Malghem J, Dion E. 2004. The normal hip joint space variations in width, shape, and architecture on 223 pelvic radiographs. Ann Rheum Dis 63:1145–1151. Lewinnek GE, Lewis J, Tarr R, Compere C, Zimmerman J. 1978. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 60:217–220. Minoda Y, Kadowaki T, Kim M. 2006. Acetabular component orientation in 834 total hip arthroplasties using a manual technique. Clin Orthop Relat Res 445:186–191. Murphy SB, Kijewski PK, Millis MB, Harless A. 1990. Acetabular dysplasia in the adolescent and young adult. Clin Orthop Relat Res 261:214–223. Nelitz M, Guenther K, Gunkel S, Puhl W. 1999. Reliability of radiological measurements in the assessment of hip dysplasia in adults. Br J Radiol 72:331–334. Nicholls AS, Kiran A, Pollard TCB, Hart DJ, Arden C, Spector T, et al. 2011. The association between hip morphology parameters and nineteen-year risk of end-stage osteoarthritis of the hip: A nested case–control study. Arthritis Rheum 63:3392–3400. Oladipo G, Okoh PD, Suleiman YA. 2010. Acetabular morphometry for determining hip dysplasia in the Nigerian population. Res J Med Sci 5:125–128. Parvizi J, Tarity TD, Slenker N, Wade F, Trappler R, Hozack WJ, et al. 2007. Proximal femoral replacement in patients with nonneoplastic conditions. J Bone Joint Surg Am 89:1036–1043. Peters FM, Greeff R, Goldstein N, Frey CT. 2012. Improving acetabular cup orientation in total hip arthroplasty by using smartphone technology. J Arthroplasty 27:1324–1330. Pierchon F, Pasquier G, Cotten A, Fontaine C, Clarisse J, Duquennoy A. 1994. Causes of dislocation of total hip arthroplasty. CT study of component alignment. J Bone Joint Surg Br 76:45–48. Sharp IK. 1961. Acetabular dysplasia: The acetabular angle. J Bone Joint Surg Br 43:268. Soong M, Rubash HE, Macaulay W. 2004. Dislocation after total hip arthroplasty. J Am Acad Orthop Surg 12:314–321. Tallroth K, Lepist€ o J. 2006. Computed tomography measurement of acetabular dimensions: Normal values for correction of dysplasia. Acta Orthop 77:598–602. Ttinnts D. 1976. Normal values of the hip joint for the evaluation of X-rays in children and adults. Clin Orthop Relat Res 119:39–47. Tuck SP, Pearce MS, Rawlings DJ, Birrell FN, Parker L, Francis RM. 2005. Differences in bone mineral density and geometry in men and women: The Newcastle Thousand Families Study at 50 years old. Br J Radiol 78:493–498. Tuck SP, Rawlings DJ, Scane AC, Pande I, Summers GD, Woolf AD, et al. 2011. Femoral neck shaft angle in men with fragility fractures. J Osteoporos 2011: 903726. Umer M, Sepah YJ, Asif S, Azam I, Jawad MU. 2009. Acetabular morphometry and prevalence of hip dysplasia in the South Asian population. Orthop Rev (Pavia) 1:34–38. Vandenbussche E, Saffarini M, Taillieu F, Mutschler C. 2008. The asymmetric profile of the acetabulum. Clin Orthop Relat Res 466: 417–423. Wiberg G, Frey HD. 1939. Studies on dysplastic acetabula and congenital subluxation of the hip joint: With special reference to the complication of osteoarthritis. Acta Chir Scand (Suppl 58) 83:1–135. Yoshimura N, Campbell L, Hashimoto T, Kinoshita H, Okayasu T, Wilman C, et al. 1998. Acetabular dysplasia and hip osteoarthritis in Britain and Japan. Br J Rheumatol 37:1193–1197. Yoshimine F. 2006. The safe-zones for combined cup and neck anteversions that fulfill the essential range of motion and their optimum combination in total hip replacements. J Biomech 39:1315–1323. Zeng Y, Wang Y, Zhu Z, Tang T, Dai K, Qiu S. 2011. Differences in acetabular morphology related to side and sex in a Chinese population. J Anat 220:256–262.
Three-Dimensional Computed Tomography Reconstruction Measurements of Acetabulum in Chinese Adults HECHENG MA,1 YINGYING HAN,2 QIWEI YANG,2 YUBAO GONG,1 SHUANG HAO,3 YOUQIONG LI,4 AND JIANGUO LIU2* 1 Department of Orthopaedics, The First Hospital of Jilin University, Changchun, Jilin 130021, China 2 China-Japan Union Hospital of Jilin University, Changchun, Jilin 130021, China 3 The Second Hospital of Jilin University, Changchun, Jilin 130021, China 4 Department of Anatomy, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin 130021, China
ABSTRACT The present study was designed to define the morphological dimensions of the acetabulum in normal Chinese adults and to statistically compare these data with the available data worldwide. This information is important for the diagnosis of dysplasia and treatment of total hip arthroplasty. In this study, the gender and bilateral differences were evaluated. One-hundred CT scans of patients were retrospectively studied. These individuals showed no signs of developmental disturbances in either of the hip joints. Thirty-five morphometric parameters of the acetabulum were measured. The size of acetabulum was evaluated by the acetabular perimeter, anteroposterior diameter, vertical diameter, the depth and width of fossa ovalis in both transaxial and coronal plane. The parameters of acetabular orientation were the acetabular angle, anterior center edge angle, neck shaft angle, acetabular anteversion, and abduction angle. The coverage of acetabulum was examined as the, acetabular head index, center edge angle, the distance between the femoral head, and acetabulum. Gender and bilateral differences were analyzed for each parameter, and compared with available worldwide data. The results showed statistically significant differences between the Chinese genders and also between the Chinese and other human races in some parameters. In conclusion, gender, bilateral and racial differences exist in the morphology of acetabulum. The data may be helpful for the design of total hip arthroplasty for the Chinese population. Anat Rec, 297:643–649, C 2014 Wiley Periodicals, Inc. 2014. V
Key words: acetabulum; computed tomography; hip dysplasia; Chinese; gender; race; bilateral
Developmental dysplasia of the hip (DDH), a serious disease of the hip, is closely associated with morphological abnormalities of the acetabulum, particularly acetabular size, width, depth, orientation and the coverage of a femoral head. It is characterized by an anteverted shallow acetabulum with deficient anterior, superior or lateral coverage of the femoral head (Murphy et al., 1990). C 2014 WILEY PERIODICALS, INC. V
*Correspondence to: Jianguo Liu, Department of Orthopaedics, The First Hospital of Jilin University, Changchun, Jilin 130021, China. E-mail: [email protected] Received 13 June 2013; Accepted 23 December 2013. DOI 10.1002/ar.22885 Published online 11 February 2014 in Wiley Online Library (wileyonlinelibrary.com).
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TABLE 1. Morphometric measurements performed on 100 people acetabulum (No. 1–27 are measured on CT workstation, while No. 28–32 are measured on Efilm workstation) No. 1 2 3 4
Name AP AWt AWc
Figure
Measurement
1 1 1 2
Acetabular perimeter The width between the most anterior and posterior point in transaxial plane The width between the highest and low point in coronal plane The distance between the anterior acetabulum and the femoral head in transaxial plane The distance between the posterior acetabulum and the femoral head in transaxial plane The distance between the lateral margin of acetabulum and the femoral head in coronal plane The distance between highest point of acetabulum and the femoral head in coronal plane The least thickness of the bone of acetabulum in transaxial plane The width of fossa ovalis in transaxial plane The depth of fossa ovalis in transaxial plane The least thickness of the bone of acetabulum in coronal plane The width of fossa ovalis in coronal plane The depth of fossa ovalis in coronal plane The area that is enclosed by acetabulum and line between the anterior and posterior point The area that is enclosed by acetabulum and the femoral head The area that is enclosed by the line between anterior and posterior point and the femoral head The angle of the horizon and a line through the most superior point of the acetabular joint surface and anterior rim of the acetabulum The angle by the horizontal axis and a line running through the center point and the anterior point of acetabular in transaxial plane The angle by the horizontal axis a line running through the center point and the posterior point of acetabular in transaxial plane The angle by the vertical axis and a line running through the center point and the high lateral margin acetabular in coronal plane The angle by the vertical axis and a line running through the center point and the low lateral margin acetabular in coronal plane The angle between a line combining the anterior and posterior margins of the acetabulum and a sagittal line in transaxial plane The angle between a line combining the high and low margins of the acetabulum and the vertical axis line in coronal plane The angle between a line through the anterior margins of acetabulum and the posterior margin of fossa ovalis and the coronal line in the transaxial plane The angle between a line through the posterior of acetabulum and the posterior margin of fossa ovalis and the coronal line in the transaxial plane The angle between a line through the high margin of acetabulum and fossa ovalis and the vertical axis line in the coronal plane The angle between a line through the low margin of acetabulum and the high margin of fossa ovalis and the vertical axis line in the coronal plane The depth of acetabulum in coronal plane The depth of acetabulum in transaxial plane The distance of the highest margin of acetabulum to the horizontal line through the lateral margin of acetabulum in coronal plane The distance of the two vertical axis lines that through either innermost of femoral head or lateral margin of acetabulum in coronal plane The diameter of the femoral head The angle of the long femoral shaft and the head Coverage rate is a rate of No.15/No.14 Acetabulum head index is a rate of No. 31/No. 32
5
2
6
7
7
7
8 9 10 11 12 13 14
2 2 2 7 7 7 3
15 16
3 3
17
ACE
1
18
AnCE
4
19
PCE
4
20
CE
8
21
ICE
8
22
AcetAV
5
23
AcetAD
9
24
AnAA
6
25
PAA
6
26
AA
10
27
IAA
10
28 29 30
ADc ADt
9 5 7
31 32 33 34 35
11 NSA CR AHI
11 12
The key to diagnosis of acetabular dysplasia lies in the accurate evaluation of quantitative parameters of the acetabulum. Furthermore, total hip arthroplasty (THA), performed worldwide, has resulted in favorable clinical outcomes (Faldini et al., 2011). However, a malpositioned acetabular prosthesis during THA can result in dislocation, pelvic osteolysis, limited range of motion, polyethylene wear, and component migration (Parvizi et al., 2007). To avoid THA complications, the prosthesis must be placed in the right position (Biedermann et al., 2005) and the
prosthesis should well match the anatomy of the individual patient. Thus having accurate morphology of the acetabulum improves the clinical outcomes of THA. Because there are ethnicity differences in the morphology of the acetabulum, different surgical guides have been developed for THA (Lewinnek et al., 1978). Presently, however, there are few studies concerning the morphology and morphometrics of acetabular anatomy in normal Chinese adults. In this paper, acetabulum CT scans were measured, retrospectively, from 100 hundred individuals who
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
645
Fig. 1. 1–12 Schematic drawings of measurements 1–33 (the horizontal line is in parallel with the line between the right and left center point of the head of femur, the sagittal line is perpend.
showed no signs of developmental dysplasia in their hips. The purpose of this study was to show the morphology and morphometrics of Chinese acetabulum and statistically compare them with the available data from other ethnic groups. The second purpose of this study was to determine the variations that occur in normal hips, and in any underlying differences concerning their gender, bilateral sides and races.
MATERIALS AND METHODS
Methods All patients underwent a routine scan on a CT scanner (Toshiba Aquilion One). The patients were positioned with their legs fully extended and feet stabilized in a neutral position. With the following parameters: 140 kV, 250 mA, and standard algorithm, Heli-cal 0.5-mm CT sections were obtained. The data were transferred to a diagnostic workstation and reconstructed with the ViteaFx software. Images in the transaxial, coronal, and sagittal planes were routinely reformatted and measured.
Patients
CT Evaluation
Ethics and scientific committee approvals were obtained from our institution for this study and informed consents were obtained from all participants. This retrospective study was performed at the Jilin University Hospital. Using the hospital’s archiving system, information was obtained on hip CT scans. In this series, individuals with signs of osteoarthrosis, arthritis, congenital, or developmental structural changes were excluded. Ultimately, 100 patients (54 females and 46 males), presenting no signs of developmental dysplasia in either hip, were investigated. The mean age of the female was 61.6 years (range, 24–88 years), with the mean height being 161 cm (range, 152– 181 cm). The mean age of the male was 51.7 years (range, 19–76 years), with the mean height being 173 cm (range, 155–189 cm). Both sides of their acetabulums had been CT-scanned and three-dimensionally reconstructed, and no abnormalities were found.
The measurement was carried out on the workstation. A complete list of all measurements performed is given in Table 1. The figures (Fig. 1) also illustrate most of these measurements.
Statistical Analysis Distribution of the values was estimated by descriptive statistical analyses. The parameters including the sex and race differences were assessed using the two independent sample t test (SPSS17.0). P < 0.05 were considered statistically significant.
RESULTS A total of 33 measurements were performed on each acetabulum. The orientation of acetabulum were the
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TABLE 2. Results of morphometric measurements on 100 intact human people’s CT scan (distances are given in mm, except No. 28–32 given in cm, angles are given in degrees, the areas are given in mm2) Female
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Male
Left
Right
Left
Right
P0 value
P00 value
177.5 6 9.9 49.1 6 2.4 51.0 6 3.4 3.3 6 0.8 2.7 6 0.8 4.7 6 1.2 2.8 6 1.1 4.0 6 1.4 26.6 6 3.9 6.7 6 1.5 4.1 6 1.6 21.0 6 3.6 4.5 6 1.0 738.2 6 126.1 205.2 6 43.3 1657.9 6 237.8 29.1 6 5.7 31.2 6 8.5 11.7 6 5.9 34.6 6 6.6 63.4 6 5.3 21.6 6 5.6 50.4 6 3.9 80.4 6 6.9 22.8 6 6.3 9.0 6 5.9 111.9 6 5.8 1.8 6 0.2 2.3 6 0.3 0.3 6 0.2 3.8 6 0.3 4.3 6 0.3 126.7 6 3.6 28.0 6 4.9 88.0 6 7.3
179.4 6 10.4 49.4 6 2.4 49.3 6 2.5 3.2 6 0.8 2.5 6 0.9 5.4 6 1.3 2.8 6 1.1 3.6 6 1.1 25.6 6 3.3 6.5 6 1.4 3.8 6 1.1 20.7 6 4.3 4.4 6 1.0 710.2 6 109.7 187.0 6 41.2 1668.0 6 247.8 30.7 6 5.1 30.0 6 8.5 10.6 6 7.1 35.1 6 6.1 63.8 6 6.3 21.1 6 6.0 51.3 6 3.8 79.6 6 6.8 25.4 6 5.9 9.7 6 5.8 111.2 6 5.6 1.8 6 0.2 2.3 6 0.3 0.3 6 0.2 3.7 6 0.3 4.3 6 0.3 126.2 6 3.8 26.4 6 4.8 86.6 6 5.2
197.7 6 12.3 53.8 6 2.8 56.1 6 3.1 3.6 6 1.0 2.6 6 1.0 4.8 6 1.4 3.2 6 0.8 4.2 6 1.3 27.1 6 4.4 6.9 6 1.8 4.2 6 1.3 22.6 6 4.8 5.1 6 1.4 941.3 6 152.5 247.1 6 70.5 1605.6 6 251.7 27.9 6 6.3 30. 1 6 7.1 11.5 6 6.3 37.0 6 5.7 63.0 6 4.3 20.4 6 5.5 51.3 6 3.7 77.1 6 6.9 24.2 6 5.5 7.7 6 6.1 110.3 6 6.3 2.1 6 0.2 2.6 6 0.3 0.5 6 0.2 4.2 6 0.3 4.8 6 0.3 127.6 6 3.8 26.5 6 6.7 87.5 6 4.8
200.8 6 10.8 54.4 6 2.6 56.3 6 2.7 3.5 6 1.1 2.7 6 0.9 4.9 6 1.4 3.4 6 1.0 4.1 6 1.4 26.5 6 4.2 6.7 6 1.7 4.2 6 1.2 22.5 6 5.0 5.0 6 1.4 919.0 6 148.3 221.8 6 57.4 1615.8 6 255.8 28.3 6 6.5 30.3 6 8.3 11.7 6 6.7 38.0 6 8.9 63.5 6 7.1 20.3 6 5.8 52.1 6 4.8 75.6 6 6.4 26.9 6 5.4 8.2 6 6.8 110.7 6 6.5 2.1 6 0.3 2.5 6 0.3 0.4 6 0.2 4.3 6 0.4 5.0 6 0.5 126.0 6 3.8 24.4 6 5.7 87.1 6 5.4
P < 0.001 P < 0.001 P < 0.001 P < 0.01 P > 0.05 P > 0.05 P < 0.05 P < 0.01 P > 0.05 P > 0.05 P > 0.05 P < 0.01 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P < 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.001 P > 0.05 P < 0.05 P > 0.05 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P < 0.001 P > 0.05 P < 0.05 P > 0.05
P < 0.01 P > 0.05 P > 0.05 P < 0.01 P > 0.05 P < 0.01 P > 0.05 P > 0.05 P < 0.01 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P < 0.001 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P < 0.001 P > 0.05 P > 0.05 P > 0.05 P < 0.05 P > 0.05 P > 0.05 P > 0.05 P > 0.05 P < 0.01 P > 0.05
P0 value: male versus female hip; P00 value: left versus right side.
lateral, inferior, anterior, and posterior AA angle and CE angles, ACE angle, AcetAV angle, AcetAD angle, neck shaft angle. The size of acetabulum was assessed by the diameter, the depth, and width of the acetabulum and fossa ovalis both in transaxial and coronal planes. The coverage of the acetabulum were interpreted by the CE angle, CR, AHI, the distance between the head of femur of acetabulum. The detailed results are present in Table 2. The comparisons of the mean parameters in female with those in male and the bilateral parameters are shown in Table 2.
clinical outcomes in treating the acetabular dysplasia (Faldini et al., 2011). A malpositioned acetabular prosthesis and an unfit prosthesis during THA may result in dislocation, pelvic osteolysis, limited range of motion, polyethylene wear, and component migration (Parvizi et al., 2007). To avoid these complications, an understanding of the morphology of acetabulum in the individual patient is important for a successful clinical outcome from the surgery. In the present study, the normal, nondiseased, acetabular morphology in Chinese population is described.
The Orientation of Acetabulum DISCUSSION Computed tomography has proven to be a practical approach to assess acetabular deformity and acetabular morphology. An understanding of the normal range of acetabular morphometric parameters has been the key to distinguish acetabular deformity from normal anatomical variations (Chiron et al., 2012). However, the range of normal acetabular variations may differ between races and genders (Nicholls et al., 2011). While total hip arthroplasty (THA) has generally favorable
In the present study, the orientation of the acetabulum was described by the acetabular angle, anterior center-edge angle, neck shaft angle, acetabular anteversion, and abduction angle. The published values of the acetabular orientation by ethnic groups are shown in Table 3. Acetabular angle, originally described by Sharp (1961), is considered as the most important indicator in the diagnosis of dysplasia of the acetabulum. The comparisons shown in Table 3 provide clear evidence that variations exist between different races. The AA angle
Lavy et al. (2003) Jeremic´ et al. (2011) Stem et al. (2006) Lequesne et al. (2004) Tuck et al. (2005) Nelitz et al. (1999) Murtha et al. (2008) – – – – – – – 132.83 6 4.37 – 128 6 1.7 130 6 3.3 – 137.3 6 9.0 55.5 6 10.4 – – – –
– – – 19.3 6 10.8
– – 39.0 6 4.0 – – – 57.1 6 9.1 – –
– – 23.0 6 5.0 – – – 24.1 6 9.2
–
– –
36.65 6 4.61 35.66 6 4.68 38.6 6 4.9 38.5 6 3.9 – 3.63 6 4.52 39.0 6 3.2 43.5 6 4.3 – Malawian Serbian American France British German American
L R Nigerian
36.2 6 2.8
12.34 6 7.5 15.8 6 8.72 – 9.0 6 6.0 – – – 35.60 6 4.70 35.47 6 4.11 36.9 6 4.0 37.5 6 3.6 –
– 39.0 6 3.2 41.8 6 3.4 Japanese
– 9.19 6 6.24 36.5 6 3.5 37.31 6 4.27 37.5 6 3.8 38.28 6 4.43 Korean South Asian
Finnish
Chinese
L R
– – 164
– – 565
– – 30 6 4
–
–
12.74 6 10 16.97 6 7.69 – 6.2 6 4.9 – – –
–
–
–
–
–
– – 44.4 6 6.5 17.9 6 6.3 –
– 11.68 6 6.0
– –
– –
– –
– –
– –
– –
Tallroth and Lepist€o (2006) Han et al. (1998) Fujii (2001), Umer et al. (2009), Fujii (2001), Minoda et al. (2006) Oladipo et al. (2010)
Zeng et al. (2011)
– – – – – – 39.5 6 3.62 40.2 6 3.03 – 41.2 6 3.98 42.2 6 3.87 – 18.1 6 5.55 16.0 6 5.74 17 6 6 17.6 6 4.8 0 18.1 6 5.55 23 6 7 – – 31 6 4
Male Female Male Female Male Female Male Female Male Female
Neck shaft angle Acetabular abduction angle Acetabular anteversion angle Anterior center-edge angle Acetabular angle
TABLE 3. Published values of the acetabular orientation by ethnic groups ( )
References
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
647
described in a Finnish population (Tallroth and Lepist€o, 2006) is in accordance with the present observations in the Chinese populations. It should be noted that there were significant gender differences in both populations. However, the AA angle of other races were much larger than that observed in the present study (P < 0.001), perhaps due in part to the different methods that were used in these measurements. Even though there were variations in the anatomical landmarks used in the measurements in different studies, all conclude that there were significant gender differences. The ACE angle is an effective measurement to show the superior–anterior coverage of the femoral head (Lequesne, 1961). Several studies of different races in Table 3 indicate that the results from the Chinese population differ from other races except for the Finnish populations. Some of these differences may be due to different methods being used (i.e., X-ray radiography and CT), however there were gender differences except in the Finnish population. AcetAV angle and AcetAD angle are two important angles to describe the orientation of the acetabulum (Anda et al., 1991; D’Lima et al., 2000). It is important during THA to place the prosthesis in the right position (Ghelman et al., 2009), or serious postoperative complications could occur (Minoda et al., 2006). A “safe zone” for the orientation of the acetabular component (abduction 40 6 10 , anteversion 20 6 5 ) has been recommended (Soong et al., 2004) to best avoid these complications. However, this “safe zone” does vary with age, gender, and race in acetabular orientation. The comparisons presented in Table 3 raise the intriguing possibility that acetabular anteversion in the American, Finnish, and Japanese populations are significantly larger in females than males, and this differs from the findings in Chinese population. Neither the southeast Chinese (Zeng et al., 2011) nor the present observation show any gender differences in the anteversion of acetabulum. Furthermore, the Chinese AcetAV angle was much larger than the Japanese, comparable with the AcetAV angle of the Americans and Finnish populations. As for the AcetAD angle, Zeng et al. (2011) reports that it is larger in southeast Chinese females than males (P < 0.001), which is inconsistent with the present findings. In addition, the AcetAV angle reported here differs from other races. No significant gender difference was found in both AcetAV angle and AcetAD angle and this differs from the results of others. It should be emphasized that it is the acetabular orientation that is important for the success of the THA procedure (Biedermann et al., 2005; Ghelman et al., 2009; Minoda et al., 2006; Lewinnek et al., 1978) and the parameters defined in the present study should help guide surgeons for procedures in the Chinese population. The femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk (Alonso et al., 2000; Gnudi et al., 2011). In a United Kingdom (UK) population (Tuck et al., 2005), the NSA in the female was significantly smaller than in the male, which is inconsistent with those measured in the present study. Tuck et al. (2005) found that the mean NSA was significantly smaller in those with vertebral fractures, but larger in those with distal forearm fractures (P 5 0.01), suggesting that femoral NSA is determinant of hip fracture risk in UK men (Tuck et al., 2011).
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TABLE 4. The published values of the acetabular size by ethnic groups AD (mm) Chinese
L R
Japanese British Austrian
AW (mm)
AP (mm)
Female
Male
Female
Male
Female
Male
17.5 6 1.68 19.4 6 2.21 9.2 6 0.5 14.4 6 0.2 10.2 6 2.7
19.4 6 2.21 19.3 6 2.48 8.9 6 0.5 14.4 6 0.4 11.5 6 2.6
51.4 6 2.07 51.4 6 2.38 – – 48.3 6 3.3
56.0 6 3.33 55.2 6 3.11 – – 49.5 6 2.3
–
–
– – 68.5 6 2.9
– – 65.9 6 5.2
–
–
47.8 6 2.3
56.3 6 2.6
147.5 6 6.4
170.6 6 7.9
Italian
Zeng et al. (2011) Yoshimura et al. (1998) Genser-Strobl and Sora (2005) Benazzi et al. (2008)
TABLE 5. The published values of the acetabular coverage by ethnic groups CE ( )
AHI (%)
South Asian Nigerian Malawian British Japanese Japanese
L R
Female
Male
Female
Male
References
89.0 6 6.0 46.0 6 5.7 48.0 6 4.7 84.8 6 5.0 81.6 6 5.0 80.6 6 6.4 81.7 6 4.6
87.0 6 5.0 48.0 6 0.3 47.0 6 0.5 85.5 6 5.1 82.3 6 5.2 81.1 6 5.0 88.5 6 6.6
34.57 6 6.78 33.98 6 6.09 33.17 6 6.80 34.3 6 7.5 30.4 6 5.4 27.9 6 6.5
36.28 6 6.44 34.80 6 6.99 32.43 6 7.74 34.0 6 7.5 31.7 6 5.5 29.5 6 5.9
Umer et al. (2009) Oladipo et al. (2010)
German
74.3 6 7.9
Several studies of different races in Table 3 indicate that all races share a similar NSA. The inferior, anterior, and posterior acetabular angles were also measured. These angles have not previously been measured and these values may provide additional data of great value for surgical procedures in the acetabulum (Peters et al., 2012; Pierchon et al., 1994; Yoshimine, 2006). There were, however, significant differences between female and male. Thus, taking all into consideration, these parameters describing the acetabular orientation give an evidence on the guide of THA on different race and genders.
The Size of Acetabulum The size of acetabulum is important for prosthetic design (Berry et al., 2005). And the published values of the acetabular orientation by ethnic groups are shown in Table 4.The depth of acetabulum (AD) is considered as a very important measurement for acetabular dysplasia and osteoarthritis (Lequesne et al., 2004; Yoshimura et al., 1998). There are gender differences in these parameters in Chinese and other races (Table 4). However, the AD found in the present study is larger than that reported for Japanese, British, and Austrian (Genser-Strobl and Sora, 2005; Yoshimura et al., 1998). Among the published value in Table 4, a significant difference exists in different races. Furthermore, differences exist between coronal and transaxial plane in our observation. The depth of acetabulum in the transaxial plane is much larger than that in the coronal plane. This means the acetabulum is not vertical. As for the width of acetabulum (AW), our result is similar to other published results on Chinese (Zeng et al., 2011), with a significant difference between female and male. However, the AW of Austrian (Genser-Strobl and Sora, 2005)
>25 23.5 6 7.8
Lavy et al. (2003) Chosa and Tajima (2003) Nelitz et al. (1999)
and Italian (Benazzi et al., 2008) much smaller than other results, including Chinese.
The Coverage of Acetabulum The acetabular head index (AHI) is classical used to assess femoral head coverage (Chosa and Tajima, 2003). A report of south Asian by Umer et al. (2009) showed the mean AHI is quite similar to ours with no gender difference. However, other researches in Table 5 about Nigerian, British, and German suggest much smaller than ours, especially the Nigerian. It is reasonable that the races lead to the different AHI. The center edge angle (CE angle), originally described by Wiberg and Frey (1939), is perhaps the most popular indicator estimated in most of the radiographic classifications, which evaluates the degree of lateral overage of the femoral head in the frontal plane (Ttinnts, 1976). Many authors have reported the CE angle of their own races, and race differences can be obviously seen from Table 5. There are significant gender differences in all races except two African countries Malawian and Nigeria. The CE angle of Japanese and German are much smaller than others. Taken all into consideration, the differences in the coverage of the acetabulum lead to different diagnosis of DDH and different surgery strategy. Furthermore, the distance between the femoral head and the acetabulum were also measured in anterior, superior, lateral, and posterior site of acetabulum. All these parameters clearly indicate the coverage of acetabulum. The coverage of acetabulum changed once DDH or acetabular fracture happened. So it is a very important morphological parameter to diagnosis the DDH and fracture. Interestingly, apart from the gender and racial difference, the bilateral difference has also been analyzed. According to the recent research, no bilateral differences
MEASUREMENTS OF ACETABULUM IN CHINESE ADULTS
were found in all except Vandenbussche’s report (2008), which confirmed and quantified the asymmetry of the acetabular rim. It is the same with our observation. There are no significant differences in this common parameter of Chinese acetabulum. However, the new parameters that never conducted by others show a little difference, such as the acetabular perimeter, the distance between the acetabulum and the femur head shown in Table 2. A better understanding of the difference remains to be elucidated in more detail. In conclusion, new morphometric data on the hip joint specific for Chinese populations were raised in the present study and all the parameters defined should help guide surgeons for procedures in the Chinese population. A well understanding of the morphometry and morphology of acetabulum in the individual patient is important for a successful clinical outcome from the surgery. Secondly, there were significant gender and racial differences in most measurements.
ACKNOWLEDGEMENTS The authors are grateful to the department of radiology, China-Japan Friendship Hospital for achieving the measurement.
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