Abstract
Background
The normal references for acetabular parameters are important for the diagnosis of hip diseases and planning of total hip arthroplasty. There are wide interindividual differences in acetabular morphology in the normal population, and little is known about differences in acetabular morphology in the average South Korean population. The purpose of this study was to evaluate side and sex differences in acetabular morphology in the South Korean population.
Methods
The acetabular parameters, including anteversion angle, abduction angle, center-edge angle, acetabular width and depth, and acetabular-head index, were measured on three-dimensional computed tomography images in 197 healthy Korean adults. Differences in acetabular parameters according to side and sex were evaluated.
Results
The mean acetabular anteversion angle of men and women was 17.3° ± 5.2° and 20.1° ± 3.5°, respectively. The mean acetabular width of men and women was 61.5 ± 4.6 cm and 56.5 ± 4.0 cm, respectively. There were significant sex differences in acetabular anteversion angle (p = 0.001) and acetabular width (p = 0.036) when adjusted for age, body height, and weight. The mean acetabular width of the right side and the left side was 60.2 ± 5.2 cm and 57.8 ± 4.5 cm, respectively. There were significant side differences in acetabular width (p = 0.007) when adjusted for age, body height, weight, and sex.
Conclusions
Differences and reference ranges of acetabular parameters are important for the diagnosis of acetabular deformity, such as femoroacetabular impingement and acetabular dysplasia. Moreover, these differences and reference ranges are useful for preoperative planning and safe positioning of acetabular components in total hip arthroplasty.
Keywords: Acetabular morphology, Sex, Three-dimensional computed tomography
The anatomic structure of the normal hip joint depends on dynamic interaction between the proximal femur and acetabulum.1,2,3) Abnormal interaction due to variation in the orientation of either the acetabulum, proximal femur, or a combination of both can directly damage the hip.4,5,6) There are two types of hip diseases associated with morphological abnormalities of the acetabulum. Acetabular dysplasia caused by an anteverted shallow acetabulum is associated with deficiency of anterior, superior, or lateral coverage of the femoral head.7) Causes of pincer-type femoroacetabular impingement (FAI) include increased acetabular depth and acetabular retroversion, leading to anterior or lateral overcoverage of the femoral head.8) Normal references for acetabular parameters are needed because the diagnosis of these two diseases depends on quantitative parameters of the acetabulum.9,10) Normal references for acetabular parameters are also essential for total hip replacement arthroplasty.11) Malposition of the acetabular component in total hip arthroplasty can cause dislocation, wear, osteolysis, and limited range of motion.12,13) Although the safe range for the positioning of acetabular components has been suggested,14) there are wide interindividual variations in acetabular anatomy in normal population. Some acetabular parameters are significantly different among people depending on sex and side.15,16) Therefore, sex and side differences in acetabular anatomy should be considered for diagnosing hip diseases and planning total hip arthroplasty. However, little is known about variations of acetabular anatomy in average South Korean adults. Thus, the purpose of this study was to evaluate side and sex differences in acetabular morphology in a normal South Korean population.
METHODS
This study was approved by the Institutional Review Board of Jeju National University Hospital (No. 2020-03-033). All methods were performed in accordance with the relevant guidelines and regulations (Declaration of Helsinki). Patient informed consent was waived by the Institutional Review Board due to the retrospective nature of the study. This study retrospectively analyzed acetabular parameters in 197 healthy South Korean adults (87 men and 110 women). Patients who visited the radiology department and underwent screening for other diseases were recruited from January 2009 to December 2013. The number of the study population (n = 197) satisfied the optimal sample size calculated using G-Power program (a free statistical program available at http://www.gpower.hhu.de/). None of them suffered from hip osteoarthritis, congenital or developmental hip morphology changes such as dislocation, subluxation, or dysplasia, previous surgery, or trauma to the hip. For male patients, their mean age, height, and weight were 60.4 ± 13.8 years, 166.5 ± 7.1 cm, and 65.2 ± 9.8 kg, respectively. For female patients, their mean age, height, and weight were 68.7 ± 12.5 years, 154.2 ± 6.0 cm, and 56.0 ± 9.3 kg, respectively.
Patients were placed in supine position with the knee joints fully extended and the patella facing forward for three-dimensional computed tomography (3D-CT) examination using a 64-layer CT scanner (Siemens Medical Solutions, Erlangen, Germany). Scanning parameters were as follows: 1.0 mm in layer thickness and 0.6 mm in reconstruction interval. Data were transmitted to a Siemens image post-processing work station to obtain 3D reconstruction images. The following parameters were measured using the 3D reconstruction images. Acetabular anteversion angle (AVA) was measured on axial CT images. AVA was defined as an angle formed by a line passing through the anteroposterior acetabualr ridge and another line drawn perpendicular to a line connecting the posterior pelvic margins at the sciatic notch level (Fig. 1). Other acetabular parameters were measured on anteroposterior CT images. Acetabular width was measured as a distance between the most superolateral point and the lowermost point of the acetabulum. Acetabular depth was measured along the perpendicular line extending from the top of the acetabular roof to the bottom of the acetabulum. Center-edge angle was defined as an angle between a vertical line drawn through the femoral head center and another line passing from the femoral head center to the superolateral point of the acetabulum. Acetabular index was calculated with the following formula: depth / width × 100 (%) (Fig. 2). Acetabular abduction angle (ABA) was measured as an angle formed by a horizontal line passing through the bottom of the acetabular tear drops and a line drawn from the teardrop to the lateral margin of the acetabulum. Acetabular head index was calculated using the following formula: width of the sourcil (I) / femoral head width (H) × 100 (%) (Fig. 3).
Fig. 1. Anteversion angle was defined as an angle formed by a line (AB) passing through the anteroposterior acetabualr ridge and another line (AC) drawn perpendicular to a line (DE) drawn between posterior pelvic margins at the sciatic notch level.
Fig. 2. Acetabular width was defined as an inferior distance (AB) between the most superolateral point and the lowermost point of the acetabulum. Acetabular depth was defined as a perpendicular distance (CD) from the top of the acetabular roof to the bottom of the acetabulum. Center edge angle was defined as an angle between a vertical line (EF) passing through the femoral head center and another line (EG) drawn from the femoral head center to the superolateral point of the acetabulum.
Fig. 3. Acetabular abduction angle was defined as an angle between a horizontal line (AB) passing through the bottom of acetabular tear drops and a line (CD) drawn from the teardrop to the lateral margin of the acetabulum. Acetabular head index was calculated as follows: width of the sourcil (H) / femoral head width (I) × 100 (%).
Interobserver and intraobserver reliability was assessed using the interclass correlation coefficient of the measurments, and an agreement of 0.75 was considered excellent. Differences in acetabular parameters according to side and sex were evaluated. Each acetabular measurment was assessed using descriptive statistical analysis. Side and sex differences for each acetbular parameter were assessed using the t-test. Analysis of covariance was used to compare differences in acetabular parameters bewteen sexes and sides after adjusting for age, body height, and weight. Age and sex differences for each acetbular parameter were assessed using one way analysis of variance. A p-value ≤ 0.05 was considered statistically significant. Data were analyzed using IBM SPSS ver. 19.1 (IBM Corp., Armonk, NY, USA).
RESULTS
Each parameter showed good to excellent interobserver and intraobserver agreement. Average values of all acetabular parameters in both sexes are displayed in Table 1. Compared to men, women had significantly greater AVA (p = 0.001) and ABA (p = 0.012) and significantly smaller center-edge angle (p = 0.026), acetabular width (p < 0.001), and depth (p < 0.001). Sex differences in AVA (p = 0.001) and acetabular width (p = 0.036) were significant after adjusting for age, body height, and weight. Average values of all acetabular parameters of both sides are displayed in Table 2. There were significant side differences in acetabular width (p = 0.002), which were also significant after adjusting for age, body height, and weight (p = 0.007). Average values of all acetabular parameters by age and sex are presented in Table 3. There was no significant difference in acetabular parameters according to age.
Table 1. Differences in Acetabular Parameters in Both Sexes.
| Variable | Male (n = 87) | Female (n = 110) | p-value | p-value* |
|---|---|---|---|---|
| Age (yr) | 60.4 ± 13.8 | 68.7 ± 12.5 | < 0.001 | |
| Height (cm) | 166.5 ± 7.1 | 154.2 ± 6.0 | < 0.001 | |
| Weight (kg) | 65.2 ± 9.8 | 56.0 ± 9.3 | < 0.001 | |
| Anteversion (°) | 17.3 ± 5.2 | 20.1 ± 3.5 | 0.001 | 0.001 |
| Abduction (°) | 40.5 ± 3.6 | 42.2 ± 4.8 | 0.012 | 0.480 |
| Center-edge (°) | 37.2 ± 7.3 | 34.5 ± 7.6 | 0.026 | 0.161 |
| Width (cm) | 61.5 ± 4.6 | 56.5 ± 4.0 | < 0.001 | 0.036 |
| Depth (cm) | 26.0 ± 2.9 | 23.5 ± 3.2 | < 0.001 | 0.097 |
| Acetabular head index (%) | 84.7 ± 6.3 | 84.2 ± 6.3 | 0.619 |
Values are presented as mean ± standard deviation.
*Analysis of covariance after adjusting for age, body height, and weight.
Table 2. Differences in Acetabular Parameters between Right and Left Sides.
| Variable | Right (n = 197) | Left (n = 197) | p-value | p-value* |
|---|---|---|---|---|
| Anteversion (°) | 19.4 ± 4.4 | 18.0 ± 4.9 | 0.127 | 0.007 |
| Abduction (°) | 41.6 ± 3.5 | 41.1 ± 5.0 | 0.408 | |
| Center-edge (°) | 35.4 ± 7.2 | 36.3 ± 7.9 | 0.431 | |
| Width (cm) | 60.2 ± 5.2 | 57.8 ± 4.5 | 0.002 | |
| Depth (cm) | 25.1 ± 3.4 | 24.4 ± 3.2 | 0.219 | |
| Acetabular head index (%) | 84.8 ± 5.0 | 84.2 ± 7.3 | 0.571 |
Values are presented as mean ± standard deviation.
*Analysis of covariance after adjusting for age, body height, weight, and sex.
Table 3. Differences in Acetabular Parameters by Age and Sex.
| Parameter | Anteversion (°) | Abduction (°) | Center-edge (°) | Width (cm) | Depth (cm) | Acetabular head index (%) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Male | Female | Male | Female | Male | Female | Male | Female | Male | Female | Male | Female | |
| 30–49 yr (male : female = 15 : 11) | 18.3 ± 8.5 | 18.8 ± 3.6 | 42.1 ± 4.2 | 45.4 ± 2.9 | 38.7 ± 8.4 | 37.0 ± 6.2 | 60.5 ± 4.0 | 55.1 ± 2.2 | 26.3 ± 3.9 | 22.8 ± 2.8 | 83.9 ± 5.4 | 83.2 ± 8.8 |
| 50–59 yr (male : female = 22 : 11) | 16.4 ± 3.7 | 20.8 ± 2.1 | 41.1 ± 3.6 | 43.1 ± 3.7 | 38.5 ± 8.0 | 39.3 ± 6.9 | 59.7 ± 3.6 | 57.8 ± 3.9 | 25.4 ± 2.8 | 23.9 ± 3.2 | 82.8 ± 4.8 | 81.5 ± 7.1 |
| 60–69 yr (male : female = 18 : 23) | 15.7 ± 4.1 | 20.7 ± 3.3 | 39.7 ± 3.5 | 43.3 ± 4.3 | 36.7 ± 7.1 | 32.2 ± 8.5 | 63.1 ± 7.2 | 55.3 ± 4.9 | 26.2 ± 3.0 | 22.8 ± 3.0 | 87.4 ± 9.5 | 83.0 ± 6.2 |
| 70–79 yr (male : female = 16 : 48) | 18.0 ± 2.9 | 19.4 + 3.3 | 39.6 ± 2.4 | 42.1 ± 3.6 | 35.2 ± 5.2 | 35.0 ± 6.5 | 62.7 ± 3.0 | 56.7 ± 4.5 | 26.2 ± 1.5 | 23.7 ± 3.6 | 84.9 ± 4.4 | 85.0 ± 3.8 |
| 80–89 yr (male : female = 11 : 22) | 19.5 ± 4.5 | 22.1 ± 5.3 | 38.3 ± 6.9 | 42.3 ± 4.3 | 35.6 ± 7.1 | 37.0 ± 7.3 | 62.1 ± 1.1 | 57.2 ± 2.4 | 26.3 ± 3.3 | 23.9 ± 3.1 | 85.0 ± 3.8 | 86.9 ± 7.0 |
Values are presented as mean ± standard deviation.
DISCUSSION
The normal range of acetabular parameters is important for distinguishing acetabular deformity and planning total hip arthroplasty. However, there are wide interindividual variations of acetabular parameters in people of different sex, as well as between right and left hips. However, there is no consensus on normal ranges of acetabular parameters. There are previous studies that evaluated differences of acetabular parameters by sex and side based on plain radiography, which may not have been accurate enough due to its limitations in measurement based on positions. In the current study, 3D-CT reconstruction images were used to evaluate differences of acetabular parameters between men and women and between right and left sides. As measurements could be performed in any plane and any direction using 3D reconstruction images, 3D-CT allows more accurate measurements than plain radiography.
Previous data on sex-related difference in acetabular parameters are inconsistent. Many studies showed that AVA was significantly larger in women than in men15,17,18,19) as in our study. Acetabular parameters in normal male populations showed more retroversion of the acetabulum than in female counterparts, indicating men are anatomically more prone to pincer-type FAI. However, many clinical studies have shown that the incidence of pincer-type impingement was more frequent in women than men.3) Cobb et al.20) reported that there was no significant difference in AVA between pincer-type FAI patients and normal acetabular patients, suggesting there are other contributing factors in the higher prevalence of pincer-type FAI in women other than anatomical positions of the acetabulum. Potential causal anatomical factors such as coxa profunda, acetabular protrusions, and femoral retroversion in pincer-type FAI should be evaluated in addition to sex differences in further research. Some studies showed that acetabular width was significantly larger in men than women.18,19) However, other studies reported positive correlations between body height and acetabular size and that the difference in acetabular width between women and men was associated with body height, not sex.21) Our results showed that acetabular width was significantly different between sexes after adjusting for body height and weight.
Previous comparative studies on acetabular parameters of both acetabulums have demonstrated inconsistent results. Buller et al.22) and Tallroth and Lepisto15) failed to find significant differences in any acetabular parameters between left and right hips. However, Vandenbussche et al.19) reported differences in acetabular parameters between right and left hips. In addition, our results indicated significant differences in acetabular width between right and left acetabulums after adjusting for body height and weight. Side difference in acetabular width was also statistically significant after adjusting for body height, weight, and sex.
Inconsistent results on sex- and side-related differences in acetabular parameters in previous studies might have originated from geographic and racial differences in acetabular parameters. We summarized the acetabular parameters according to countries and confirmed that there was some difference (Table 4). The cause of these differences can be genetic or cultural (the way babies are carried may affect hip development).23) Moreover, a previous study reported that side differences of acetabular or proximal femoral parameters were associated with the dominant leg because the dominant leg may bear greater loading force than the non-dominant leg.24) Although the cause of sex- and side-related differences in acetabular parameters needs to be further studied, acetabular width is an important factor in restoring normal hip mechanics and the awareness of sex and side differences in acetabular width could be helpful for planning total hip arthroplasty.18)
Table 4. Differences in Acetabular Parameters by country.
| Parameter | Japan23) | China20) | Malaysia23) | British23) | Finland15) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Male | Female | Male | Female | Male | Female | Male | Female | Male | Female | |
| Anteversion (°) | - | - | 17.5 ± 5.73 | 18.1 ± 5.55 | - | - | - | - | 17.0 ± 6.0 | 23.0 ± 7.0 |
| Abduction (°) | 39.0 ± 3.2 | 41.8 ± 3.4 | 40.2 ± 3.03 | 42.2 ± 3.87 | 36.9 ± 4.0 | 38.6 ± 4.9 | 36.2 ± 2.8 | 39.0 ± 3.2 | - | - |
| Center-edge (°) | 29.5 ± 5.9 | 27.9 ± 6.5 | 34.4 ± 5.96 | 32.8 ± 6.29 | 34.0 ± 7.5 | 34.4 ± 7.5 | 31.7 ± 5.5 | 30.4 ± 5.4 | 39.0 ± 7.0 | 43.0 ± 7.0 |
| Acetabular-head index (%) | 81.1 ± 6.4 | 80.6 ± 6.4 | - | - | 85.5 ± 5.1 | 84.8 ± 5.0 | 82.3 ± 5.2 | 82.6 ± 5.0 | - | - |
Values are presented as mean ± standard deviation.
The safe range for the position of the acetabular component is important during total hip arthroplasty. An ABA of 40° ± 10° and an AVA of 15° ± 10° have been considered as safe zones.14) However, in the current study, we found that there were sex and side differences in AVA in a normal Koran population. Therefore, the optimal acetabular position in total hip arthroplasty differs between individuals. The exact placement of acetabular components within the safe zone may not be good for every patient. Kennedy at al.12) have suggested the use of native acetabular position as a guide for acetabular component placement during total hip arthroplasty. It is also important to evaluate the width and depth of the acetabulum in preoperative planning for total hip arthroplasty. The size of an acetabular implant is also important in total hip arthroplasty. The geographic discrepancy between the implant and acetabular anatomy often results in partial prosthetic overlap of the acetabular rim. This discrepancy leads to iliopsoas impingement caused by the chronic friction of the iliopsoas tendon and rim of the implant.19) In the current study, we found that there were sex and side differences of acetabular width in a normal Koran population. Therefore, sex and side-related differences in acetabular parameters are critical for accurate position and anatomical alignment of total hip arthroplasty components. Preoperatively determining acetabular parameters with CT scanning is important for optimum acetabular component placement in total hip arthroplasty.
This study has some limitations. First, all acetabular parameters were measured by a single investigator. Second, because of the retrospective nature of this study, the position of patients during CT scan was not fully controlled. In addition, the study sample size (197 participants) was relatively small to draw a definite conclusion. Thus, a large multicenter study is needed to investigate the reliable acetabular parameters in South Korean population. Lastly, side differences in acetabular parameters between dominant and non-dominant legs were not evaluated in the current study. This requires future investigations.
In summary, this study confirmed that there were morphological differences in the acetabulum based on sex and side. A set of reference ranges for normal acetabular parameters were provided for South Korean population. These differences and reference ranges for acetabular parameters are important for the diagnosis of acetabular deformity, such as FAI or acetabular dysplasia, and useful for preoperative planning and safe positioning of acetabular components in total hip arthroplasty. A large multicentric study is needed in the future to confirm specific reference ranges in South Korean population for total hip arthroplasty.
ACKNOWLEDGEMENTS
This work was supported by a research grant from Jeju National University Hospital in 2019.
Footnotes
CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported.
References
- 1.McKibbin B. Anatomical factors in the stability of the hip joint in the newborn. J Bone Joint Surg Br. 1970;52(1):148–159. [PubMed] [Google Scholar]
- 2.Beaupre GS, Orr TE, Carter DR. An approach for time-dependent bone modeling and remodeling-application: a preliminary remodeling simulation. J Orthop Res. 1990;8(5):662–670. doi: 10.1002/jor.1100080507. [DOI] [PubMed] [Google Scholar]
- 3.Tannenbaum E, Kopydlowski N, Smith M, Bedi A, Sekiya JK. Gender and racial differences in focal and global acetabular version. J Arthroplasty. 2014;29(2):373–376. doi: 10.1016/j.arth.2013.05.015. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Beck M, Kalhor M, Leunig M, Ganz R. Hip morphology influences the pattern of damage to the acetabular cartilage: femoroacetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br. 2005;87(7):1012–1018. doi: 10.1302/0301-620X.87B7.15203. [DOI] [PubMed] [Google Scholar]
- 5.Notzli HP, Wyss TF, Stoecklin CH, Schmid MR, Treiber K, Hodler J. The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement. J Bone Joint Surg Br. 2002;84(4):556–560. doi: 10.1302/0301-620x.84b4.12014. [DOI] [PubMed] [Google Scholar]
- 6.Reynolds D, Lucas J, Klaue K. Retroversion of the acetabulum: a cause of hip pain. J Bone Joint Surg Br. 1999;81(2):281–288. doi: 10.1302/0301-620x.81b2.8291. [DOI] [PubMed] [Google Scholar]
- 7.Cooperman DR, Wallensten R, Stulberg SD. Acetabular dysplasia in the adult. Clin Orthop Relat Res. 1983;(175):79–85. [PubMed] [Google Scholar]
- 8.Kassarjian A, Brisson M, Palmer WE. Femoroacetabular impingement. Eur J Radiol. 2007;63(1):29–35. doi: 10.1016/j.ejrad.2007.03.020. [DOI] [PubMed] [Google Scholar]
- 9.Delaunay S, Dussault RG, Kaplan PA, Alford BA. Radiographic measurements of dysplastic adult hips. Skeletal Radiol. 1997;26(2):75–81. doi: 10.1007/s002560050197. [DOI] [PubMed] [Google Scholar]
- 10.Garbuz DS, Masri BA, Haddad F, Duncan CP. Clinical and radiographic assessment of the young adult with symptomatic hip dysplasia. Clin Orthop Relat Res. 2004;(418):18–22. doi: 10.1097/00003086-200401000-00004. [DOI] [PubMed] [Google Scholar]
- 11.Della Valle AG, Padgett DE, Salvati EA. Preoperative planning for primary total hip arthroplasty. J Am Acad Orthop Surg. 2005;13(7):455–462. doi: 10.5435/00124635-200511000-00005. [DOI] [PubMed] [Google Scholar]
- 12.Kennedy JG, Rogers WB, Soffe KE, Sullivan RJ, Griffen DG, Sheehan LJ. Effect of acetabular component orientation on recurrent dislocation, pelvic osteolysis, polyethylene wear, and component migration. J Arthroplasty. 1998;13(5):530–534. doi: 10.1016/s0883-5403(98)90052-3. [DOI] [PubMed] [Google Scholar]
- 13.D’Lima DD, Urquhart AG, Buehler KO, Walker RH, Colwell CW., Jr The effect of the orientation of the acetabular and femoral components on the range of motion of the hip at different head-neck ratios. J Bone Joint Surg Am. 2000;82(3):315–321. doi: 10.2106/00004623-200003000-00003. [DOI] [PubMed] [Google Scholar]
- 14.Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am. 1978;60(2):217–220. [PubMed] [Google Scholar]
- 15.Tallroth K, Lepisto J. Computed tomography measurement of acetabular dimensions: normal values for correction of dysplasia. Acta Orthop. 2006;77(4):598–602. doi: 10.1080/17453670610012665. [DOI] [PubMed] [Google Scholar]
- 16.Krebs V, Incavo SJ, Shields WH. The anatomy of the acetabulum: what is normal? Clin Orthop Relat Res. 2009;467(4):868–875. doi: 10.1007/s11999-008-0317-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Stem ES, O’Connor MI, Kransdorf MJ, Crook J. Computed tomography analysis of acetabular anteversion and abduction. Skeletal Radiol. 2006;35(6):385–389. doi: 10.1007/s00256-006-0086-4. [DOI] [PubMed] [Google Scholar]
- 18.Murtha PE, Hafez MA, Jaramaz B, DiGioia AM., 3rd Variations in acetabular anatomy with reference to total hip replacement. J Bone Joint Surg Br. 2008;90(3):308–313. doi: 10.1302/0301-620X.90B3.19548. [DOI] [PubMed] [Google Scholar]
- 19.Vandenbussche E, Saffarini M, Taillieu F, Mutschler C. The asymmetric profile of the acetabulum. Clin Orthop Relat Res. 2008;466(2):417–423. doi: 10.1007/s11999-007-0062-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Cobb J, Logishetty K, Davda K, Iranpour F. Cams and pincer impingement are distinct, not mixed: the acetabular pathomorphology of femoroacetabular impingement. Clin Orthop Relat Res. 2010;468(8):2143–2151. doi: 10.1007/s11999-010-1347-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Daysal GA, Goker B, Gonen E, et al. The relationship between hip joint space width, center edge angle and acetabular depth. Osteoarthritis Cartilage. 2007;15(12):1446–1451. doi: 10.1016/j.joca.2007.05.016. [DOI] [PubMed] [Google Scholar]
- 22.Buller LT, Rosneck J, Monaco FM, Butler R, Smith T, Barsoum WK. Relationship between proximal femoral and acetabular alignment in normal hip joints using 3-dimensional computed tomography. Am J Sports Med. 2012;40(2):367–375. doi: 10.1177/0363546511424390. [DOI] [PubMed] [Google Scholar]
- 23.Lavy CB, Msamati BC, Igbigbi PS. Racial and gender variations in adult hip morphology. Int Orthop. 2003;27(6):331–333. doi: 10.1007/s00264-003-0507-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Chhibber SR, Singh I. Asymmetry in muscle weight and one-sided dominance in the human lower limbs. J Anat. 1970;106(Pt 3):553–556. [PMC free article] [PubMed] [Google Scholar]