Clinical effects of combined anteversion and offset on postoperative dislocation in total hip arthroplasty

doi:10.21203/rs.3.rs-1863433/v2

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Research Article

Clinical effects of combined anteversion and offset on postoperative dislocation in total hip arthroplasty

https://doi.org/10.21203/rs.3.rs-1863433/v2

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Background

Implant impingement and soft tissue tension are factors involved in dislocation after total hip arthroplasty (THA). Combined anteversion (CA) has been used as an indicator for implant placement; however, placing implants optimally remains challenging. Moreover, the effect of changes in offset on dislocation remains unclear. We aimed to clarify the effects of postoperative CA and pre- and postoperative changes in offset on dislocation.

Methods

We included patients who underwent primary cementless THA performed between 2013 and 2020. The mean values of CA and offset in the dislocation and non-dislocation groups were compared. The CA values within ± 10% of the recommended values were defined as good CA, and those outside the range were defined as poor CA. The dislocation rates in the good and poor CA groups and in the groups with and without increased offset were compared.

Results

A total of 283 hips were included. The mean values of CA in the dislocation and non-dislocation groups were significantly different (p < 0.001). The dislocation rate was significantly lower in the good CA group (p < 0.05). The dislocation rates in the groups with and without increased total offset were 0.5% and 4.3%, respectively (p = 0.004). There were no dislocations in patients with good CA and increased offset.

Conclusions

The dislocation rate was significantly lower when implants were placed within ± 10% of the recommended CA value. Our results suggest that dislocation can be avoided by placing the implant in the good CA range and considering the increase in total offset on the operative side.

Total hip arthroplasty

Dislocation

Combined anteversion

Offset

Complications after total hip arthroplasty (THA) are known to include infection, loosening, fracture, and dislocation. Of these, dislocation is one of the most serious complications that may require revision; therefore, preventing dislocation is essential [1]. Various factors are involved in dislocation after THA, including surgical, patient, and implant factors [2, 3]. Patient factors include age, cerebral dysfunction, and range of motion [2, 4]; implant factors include head diameter and neck design [2, 4]; surgical factors include operative approach, implant and bony impingement, and soft tissue strain [5]. Several studies have demonstrated that implant impingement because of inadequate implant placement is the main cause of postoperative THA dislocation [6–8].

Combined anteversion (CA), the optimal combination of cup inclination, cup anteversion, and stem anteversion to maximize the range of motion and minimize the risk of cup-neck impingement to reduce the risk of dislocation, has been reported to be a useful index for implant positioning [9–11]. Moreover, the offset is an index for bony impingement and soft tissue tension [5, 12]. However, few reports have evaluated THA dislocations based on both CA and offset. Additionally, although differences in offset between the operative and contralateral sides have been reported, the pre- and postoperative offsets on the operative side have not been described. In this study, we aimed to determine if obtaining desired CA and combined offset would lead to a reduction in hip instability in a consecutive series of hip arthroplasties.

Participants

A total of 428 consecutive hips, which underwent primary cementless THA via posterior approach from 2013 to 2020 at our institution, were included. This retrospective case-control study was conducted in compliance with the Helsinki Declaration and was approved by the institutional ethics board (19–174). The patients provided written informed consent prior to participation. Patients who used non-flatliners (n = 65), those who could not undergo postoperative computed tomography (CT) for any reason (n = 37), and those who could not be followed for more than 1 year (n = 48) were excluded. All hips were followed up for at least 1 year, during which time postoperative dislocations were recorded.

Preoperative planning

Preoperative planning was performed using a three-dimensional (3D) template (ZedHip™ Lexi Co., Ltd., Tokyo, Japan) based on preoperative CT. For the pelvic coordinates, the functional pelvic plane was used as the reference plane passing through the bilateral anterior iliac spines and parallel to the CT table [13], and for the femoral coordinates, the retrocondylar plane was used as the reference plane passing through the posterior point of the greater trochanter and the posterior points of the medial and lateral femoral condyle [14]. The target inclination of the acetabular component (cup radiographic inclination) was set to 43° in all cases. Anteversion of the femoral component (stem anteversion) was predicted by placing a stem along the shape of the proximal femur using a preoperative 3D template. The target anteversion of the acetabular component (cup anatomical anteversion) was determined for each case using Yoshimine’s CA formula (cup anatomical anteversion + cup radiographic inclination + 0.80 × stem anteversion = 90.8°) [11].

Surgical procedure and postoperative evaluation

All surgical procedures were performed in the lateral decubitus position, and a CT-based navigation system (Stryker CT-Hip System V1.1, Stryker-Leibinger GmbH & Co. KG, Freiberg, Germany) was used as the acetabular component. The posterior articular capsule and short external rotator muscles were repaired in all cases [15]. All surgeries were performed by either of the two senior authors.

A CT scan was performed at 1 week postoperatively as a routine protocol to evaluate implant placement and to confirm the presence of fractures. The postoperative CT data were imported into the template for 3D analysis. The postoperative placement angles of the acetabular and femoral components were measured using the template. Matching with the preoperative template data, a template of the same size as the actual implant was overlapped on the postoperative CT for measurement (Fig. 1). Based on these placement angles, the postoperative CA values were calculated using the formulas of Widmer et al (cup radiographic anteversion + 0.7 × stem anteversion = 37°) and Yoshimine et al [10, 11]. The mean CA values of the dislocated and non-dislocated groups were calculated and compared. Cup radiographic inclination within 35°–55° and CA values within ± 10% of the recommended values (Widmer: 37°±4°, Yoshimine: 90.8°±9°) were defined as good CA, and those outside the range were defined as poor CA. The dislocation rates in the good and poor groups were compared. The absolute values of the difference between the CA values calculated for each case and the recommended CA values using the formulas of Widmer et al and Yoshimine et al (37° and 90.8°, respectively) were calculated. Moreover, the cutoff values of CA for dislocation were examined. All offset measurements were made by projecting the distance on a horizontal plane using the template based on the preoperative and postoperative CT findings.

The horizontal distance from the pubic symphysis to the center of the femoral head was measured as the acetabular offset, and the horizontal distance from the center of the femoral head to a line passing through the center of the femoral shaft was measured as the femoral offset [16]. The sum of these offsets was defined as the total offset (Fig. 2).

The mean values of the total, acetabular, and femoral offsets on the operated side were compared between the dislocated and non-dislocated groups. The difference between the preoperative and postoperative values of each of these three offsets was divided into the postoperative increase and non-increase groups, and their dislocation rates were compared. The number of dislocations in each combination of the total offset increased/non-increased group and the CA good/poor group was investigated. The dislocation rates were also compared in cases with inner heads < 32 and ≥ 32 mm.

Statistical assessment

Demographic variables are described as means, standard deviations, and ranges for continuous data. We used the Mann–Whitney U test to compare the averages of continuous variables and Fisher’s exact test to compare the proportions of categorical variables between the groups. Receiver operator coefficient (ROC) curves were created to calculate the cutoff value of CA for dislocation. The Youden method was used to calculate the optimal threshold scores to obtain the best balance between sensitivity and specificity [17]. All statistical analyses were conducted using JMP (version 15.1.0; SAS Institute Inc., Cary, NC), with statistical significance defined as p < 0.05.

The mean follow-up period was 5.3 ± 1.8 (2.5–9) years. Patient demographics are presented in Table 1. A total of 283 hips (256 patients) were included. There were nine dislocated hips (3.2%) and 274 non-dislocated hips. Dislocation was found in nine out of 238 cases treated by the surgeon SN and in zero out of 45 cases treated by KM. There was no difference in the dislocation rates between the cases treated by these surgeons (p = 0.363). The mean CA values, as calculated by both Widmer et al’s and Yoshimine et al’s equations, were significantly different between the dislocation and non-dislocation groups. The good CA group included 158 hips according to the study of Widmer et al and 233 hips according to the study of Yoshimine et al, and dislocation was significantly lower in the good CA group for both Widmer and Yoshimine (Table 2). Based on the ROC curve analysis, the cutoff values for dislocation in Widmer’s CA and Yoshimine’s CA were 37°±3.3° and 90.8°±10.3°, respectively (Fig. 3a, 3b). The area under the ROC curve for Widmer’s CA was 0.696, the sensitivity was 0.889, the specificity was 0.471, and the Youden index was 0.36; for Yoshimine’s CA, the area under the ROC curve, sensitivity, specificity, and Youden index were 0.676, 0.556, 0.873, and 0.4, respectively. The mean total, acetabular, and femoral offsets on the operated side were not different between the dislocation and non-dislocation groups. The number of increased offsets was 169 (59.7%), 64 (22.6%), and 223 (78.8%) for total, acetabular, and femoral offsets on the operated side, respectively. Regarding the number of dislocations, the increased and non-increased groups were only significantly different in the total offset. Concerning the mean of the preoperative and postoperative differences in offset, the offsets were not significantly different between the dislocation and non-dislocation groups (Table 2). In the evaluation of dislocation using total offset and CA simultaneously, using both equations, dislocations were observed in cases with poor CA or no increase in offset, but no dislocations were observed in cases with good CA and increased offset (Table 3). The used femoral heads had sizes of 28, 32, and 36 mm; femoral heads of 28 mm were used in 57 cases, of which three were dislocated, with no significant difference in dislocation compared to cases of ≥ 32 mm (Table 4).

The investigation was performed to determine the effect of CA and offset on dislocation after THA. It was demonstrated that both Widmer’s and Yoshimine’s CA values showed a significant difference in the mean values between the dislocation and non-dislocation groups, supporting the effectiveness of CA. However, many researchers have reported that some degree of difference between preoperative target values and postoperative measured values of implant placement angle is inevitable in THA [18–20]. Considering these previous reports, it is difficult to place the cup precisely at the generally recommended combined anteversion value. Moreover, Widmer et al assume that the radiographic inclination of the cup should be in the range of 40°–45° for CA; however, it is also difficult to place the implant within this range. In this study, only 155 implants were placed within this range. Therefore, based on the aforementioned reports and considering possible CA errors in surgery, we defined good CA as a cup radiographic inclination within the range of 35–55° and within ± 10% of the recommended CA value. The results of the present study demonstrated that dislocation was significantly lower in the good CA group and the cutoff values of CA for postoperative dislocation were 37°±3.3° and 90.8°±10.3° for Widmer and Yoshimine, respectively. This range is almost the same as our definition of good CA, and it covers the pre- and postoperative differences in implant placement angles in previous reports. Significantly fewer dislocations occurred when implants were placed within this range, which is useful as an indicator of dislocation prevention. However, as cases of dislocation occurred even when implants were placed within this range, it would be difficult to prevent dislocation after THA using CA alone as an indicator of implant placement.

CA has been reported to be effective only in the prevention of implant impingement, but not in bony impingement [21]. Previous studies have shown the importance of not only implant impingement but also bony impingement and soft tissue tension in the prevention of dislocation after THA [5, 21, 22]. Studies on bony impingement have shown that increased acetabular offset provides increased range of motion for flexion and internal rotation by decreasing the effect of impingement of the greater trochanter on the anterior acetabulum [23–25]. Increased femoral offset improves hip abductor strength by lengthening the functional lever arm, reducing impingement, and increasing postoperative joint stability [22, 26] and hip range of motion [27, 28]. Thus, dislocation after THA is influenced not only by CA but also by acetabular offset and femoral offset, and all of these indicators should be considered during surgery. In this study, the results revealed no significant difference in the dislocation rate between the groups with and without increased acetabular and femoral offsets but a significant difference in the dislocation rate between the groups with and without increased total offset. In THA of patients with osteoarthritis, medialization by reaming is often necessary to place the acetabular component in an anatomically normal acetabulum [29]. The femoral offset should be increased to compensate for the decrease in acetabular offset due to the medialization. Thus, both offsets need to be evaluated [30], and avoiding a decrease in the total offset is important [31], which supports our results. In this study, the distance from the pubic symphysis to the femoral shaft was measured as the total offset; therefore, both the femoral and acetabular offsets were used in the evaluation. In both Widmer’s and Yoshimine’s CA, there were dislocations under the condition of good CA alone but not in cases with good CA and increased total offset. This suggests that dislocation can be further avoided by considering not only CA to prevent implant impingement but also the increase in total offset on the operated side to avoid soft tissue hypotension and bony impingement.

Although a previous report showed no difference in the risk of dislocation between the increased and non-increased global offset groups [32], all previous reports on offset for dislocation after THA have compared the offset between the healthy and the operative sides. Krishnan et al reported that the mean difference between the right and left sides of the normal hip offset was 2.54 ± 2.31 mm and that hip offsets are not always symmetrical even in normal hips [33]. Additionally, determining the appropriate center of rotation of the hip joint in patients with bilateral morbidity or severe dysplasia is difficult [34]. In our study, we found a significant difference in the pre- and postoperative total offset changes on the operative side between the dislocation and non-dislocation groups. This method of evaluating offset has a great advantage in that it is not affected by the condition of the contralateral hip joint. Our findings also suggest that when postoperative offset on the operative side is reduced from the preoperative offset, soft tissue tension is reduced, thus, resulting in bony impingement and increased susceptibility to dislocation. To our knowledge, no other study has compared the pre- and postoperative offsets on the affected side. In this study, regarding the occurrence of pain on the lateral side of the hip, there was no significant difference between patients with > 5 mm of postoperative femoral offset on the operated side compared with the healthy side and those with < 5 mm. Many studies have reported that pain does not increase with increasing offset, which supports our results [23, 35–38].

The limitations of this study should be noted. First, three types of femoral head sizes were used in this study. Regarding the effect of different head sizes on dislocation, many reports have shown that there was less dislocation in those sized ≥ 32 mm compared to those sized 28 mm [39]. However, in this study, no difference in dislocation was observed after comparing head sizes of 28 and ≥ 32 mm. Similar results were obtained for CA and offset for dislocation only in cases with a head size of ≥ 32 mm. Second, we used a non-flatliner to prevent dislocation in patients with inadequate intraoperative stability. These cases were excluded from the study because postoperative CT could not accurately measure the angle of placement of the non-flatliner, which may overestimate the effect of CA on dislocation. Third, the small sample size of nine patients with dislocations prohibited a multi-factor analysis. More dislocation cases should be evaluated to improve the accuracy of the analysis. Fourth, long-term adverse effects in cases of excessively increased femoral offset were not evaluated. Polyethylene wear reportedly increases when femoral offset increases by more than 5 mm compared with the normal hip joint [40]. In this study, there were 22 cases, in which femoral offset increased by ≥ 5 mm compared with the healthy side in 112 patients with unilateral disease, and the patients need to be carefully monitored in the future. Fifth, the proportion of female individuals in this study was larger than that of male individuals, showing a substantial sex bias. The reason for this is that most of the indications for total hip arthroplasty in Japan are of osteoarthritis associated with acetabular dysplasia, and the prevalence of this disease is approximately three times higher in women [41]. In the present study, the incidence of dislocation was not significantly different between men and women.

The dislocation rate was significantly lower when implants were placed within ± 10% of the recommended CA value, suggesting that placement within this range can prevent postoperative dislocation. In addition, an increase in the total offset on the operative side may prevent more dislocations.

THA

Total hip arthroplasty

Combined anteversion

ROC

Receiver operator coefficient

Three-dimensional

Ethics approval and consent to participate

This retrospective case-control study was conducted in compliance with the Helsinki Declaration and was approved by Teikyo University Medical Research Ethics Committee (19-174). The patients provided written informed consent prior to participation.

Consent for publication

All individuals have given general consent in the use of their data, including imaging, for analysis and publication.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Authors’ contributions

All authors contributed to the study conception and design. Material preparation and data collection and analysis were performed by KM and RH. The first draft of the manuscript was written by KM, and all authors commented on the previous versions of the manuscript. All authors read and approved the final manuscript.

Acknowledgments

We would like to thank Editage (www.editage.com) for English language editing.

Bozic KJ, Kurtz SM, Lau E, Ong K, Vail TP, Berry DJ. The epidemiology of revision total hip arthroplasty in the United States. J Bone Joint Surg Am. 2009;91:128–33. https://doi.org/10.2106/JBJS.H.00155.
Berry DJ, von Knoch M, Schleck CD, Harmsen WS. The cumulative long-term risk of dislocation after primary Charnley total hip arthroplasty. J Bone Joint Surg Am. 2004;86:9–14. https://doi.org/10.2106/00004623-200401000-00003.
Malkani AL, Ong KL, Lau E, Kurtz SM, Justice BJ, Manley MT. Early- and late-term dislocation risk after primary hip arthroplasty in the Medicare population. J Arthroplasty. 2010;25:21–5. https://doi.org/10.1016/j.arth.2010.04.014.
Howie DW, Holubowycz OT, Middleton R, Large Articulation Study Group. Large femoral heads decrease the incidence of dislocation after total hip arthroplasty: a randomized controlled trial. J Bone Joint Surg Am. 2012;94:1095–102. https://doi.org/10.2106/JBJS.K.00570.
Patel PD, Potts A, Froimson MI. The dislocating hip arthroplasty: prevention and treatment. J Arthroplasty. 2007;22:86–90. https://doi.org/10.1016/j.arth.2006.12.111.
Marchetti E, Krantz N, Berton C, Bocquet D, Fouilleron N, Migaud H, et al. Component impingement in total hip arthroplasty: frequency and risk factors. A continuous retrieval analysis series of 416 cup. Orthop Traumatol Surg Res. 2011;97:127–33. https://doi.org/10.1016/j.otsr.2010.12.004.
Parvizi J, Kim KI, Goldberg G, Mallo G, Hozack WJ. Recurrent instability after total hip arthroplasty: beware of subtle component malpositioning. Clin Orthop Relat Res. 2006;447:60–5. https://doi.org/10.1097/01.blo.0000218749.37860.7c.
Shon WY, Baldini T, Peterson MG, Wright TM, Salvati EA. Impingement in total hip arthroplasty a study of retrieved acetabular components. J Arthroplasty. 2005;20:427–35. https://doi.org/10.1016/j.arth.2004.09.058.
Dorr LD, Malik A, Dastane M, Wan Z. Combined anteversion technique for total hip arthroplasty. Clin Orthop Relat Res. 2009;467:119–27. https://doi.org/10.1007/s11999-008-0598-4.
Widmer KH, Zurfluh B. Compliant positioning of total hip components for optimal range of motion. J Orthop Res. 2004;22:815–21. https://doi.org/10.1016/j.orthres.2003.11.001.
Yoshimine F. 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. 2006;39:1315–23. https://doi.org/10.1016/j.jbiomech.2005.03.008.
Forde B, Engeln K, Bedair H, Bene N, Talmo C, Nandi S. Restoring femoral offset is the most important technical factor in preventing total hip arthroplasty dislocation. J Orthop. 2018;15:131–3. https://doi.org/10.1016/j.jor.2018.01.026.
Nishihara S, Sugano N, Nishii T, Ohzono K, Yoshikawa H. Measurements of pelvic flexion angle using three-dimensional computed tomography. Clin Orthop Relat Res. 2003;411:140–51. https://doi.org/10.1097/01.blo.0000069891.31220.fd.
Kingsley PC, Olmsted KL. A study to determine the angle of anteversion of the neck of the femur. J Bone Joint Surg Am. 1948;30:745–51. https://doi.org/10.2106/00004623-194830030-00021.
Zhang Y, Tang Y, Zhang C, Zhao X, Xie Y, Xu S. Modified posterior soft tissue repair for the prevention of early postoperative dislocation in total hip arthroplasty. Int Orthop. 2013;37:1039–44. https://doi.org/10.1007/s00264-013-1874-9.
Ogawa T, Takao M, Hamada H, Sakai T, Sugano N. Soft tissue tension is four times lower in the unstable primary total hip arthroplasty. Int Orthop. 2018;42:2059–65. https://doi.org/10.1007/s00264-018-3908-9.
Youden WJ. Index for rating diagnostic tests. Cancer. 1950;3:32–5. https://doi.org/10.1002/1097-0142(1950)3:1<32::aid-cncr2820030106>3.0.co;2-3.
Imai H, Miyawaki J, Kamada T, Takeba J, Mashima N, Miura H. Preoperative planning and postoperative evaluation of total hip arthroplasty that takes combined anteversion. Eur J Orthop Surg Traumatol. 2016;26:493–500. https://doi.org/10.1007/s00590-016-1777-8.
Suda K, Ito T, Miyasaka D, Imai N, Minato I, Endo N. Cup implantation accuracy using the HipCOMPASS mechanical intraoperative support device. Springerplus. 2016;5:784. https://doi.org/10.1186/s40064-016-2503-z.
Inaba Y, Kobayashi N, Suzuki H, Ike H, Kubota S, Saito T. Preoperative planning for implant placement with consideration of pelvic tilt in total hip arthroplasty: postoperative efficacy evaluation. BMC Musculoskelet Disord. 2016;17:280. https://doi.org/10.1186/s12891-016-1120-x.
Weber M, Woerner M, Craiovan B, Voellner F, Worlicek M, Springorum HR, et al. Current standard rules of combined anteversion prevent prosthetic impingement but ignore osseous contact in total hip arthroplasty. Int Orthop. 2016;40:2495–504. https://doi.org/10.1007/s00264-016-3171-x.
Jinno T, Koga D, Asou Y, Morita S, Okawa A, Muneta T. Intraoperative evaluation of the effects of femoral component offset and head size on joint stability in total hip arthroplasty. J Orthop Surg (Hong Kong). 2017;25:2309499016684298. https://doi.org/10.1177/2309499016684298.
Cassidy KA, Noticewala MS, Macaulay W, Lee JH, Geller JA. Effect of femoral offset on pain and function after total hip arthroplasty. J Arthroplasty. 2012;27:1863–9. https://doi.org/10.1016/j.arth.2012.05.001.
Matsushita A, Nakashima Y, Jingushi S, Yamamoto T, Kuraoka A, Iwamoto Y. Effects of the femoral offset and the head size on the safe range of motion in total hip arthroplasty. J Arthroplasty. 2009;24:646–51. https://doi.org/10.1016/j.arth.2008.02.008.
Kurtz WB, Ecker TM, Reichmann WM, Murphy SB. Factors affecting bony impingement in hip arthroplasty. J Arthroplasty. 2010;25:624–34. https://doi.org/10.1016/j.arth.2009.03.024.
Bourne RB, Rorabeck CH. Soft tissue balancing: the hip. J Arthroplasty. 2002;17:17–22. https://doi.org/10.1054/arth.2002.33263.
Charles MN, Bourne RB, Davey JR, Greenwald AS, Morrey BF, Rorabeck CH. Soft-tissue balancing of the hip: the role of femoral offset restoration. Instr Course Lect. 2005;54:131–41. https://doi.org/10.2106/00004623-200405000-00030.
Liebs TR, Nasser L, Herzberg W, Rüther W, Hassenpflug J. The influence of femoral offset on health-related quality of life after total hip replacement. Bone Joint J. 2014;96:36–42. https://doi.org/10.1302/0301-620X.96B1.31530.
Merle C, Innmann MM, Waldstein W, Pegg EC, Aldinger PR, Gill HS, et al. High variability of acetabular offset in primary hip osteoarthritis influences acetabular reaming-a computed tomography-based anatomic study. J Arthroplasty. 2019;34:1808–14. https://doi.org/10.1016/j.arth.2019.03.065.
Dastane M, Dorr LD, Tarwala R, Wan Z. Hip offset in total hip arthroplasty: quantitative measurement with navigation. Clin Orthop Relat Res. 2011;469:429–36. https://doi.org/10.1007/s11999-010-1554-7.
Clement ND, S Patrick-Patel R, MacDonald D, Breusch SJ. Total hip replacement: increasing femoral offset improves functional outcome. Arch Orthop Trauma Surg. 2016;136:1317–23. https://doi.org/10.1007/s00402-016-2527-4.
Mahmood SS, Mukka SS, Crnalic S, Wretenberg P, Sayed-Noor AS. Association between changes in global femoral offset after total hip arthroplasty and function, quality of life, and abductor muscle strength. A prospective cohort study of 222 patients. Acta Orthop. 2016;87:36–41. https://doi.org/10.3109/17453674.2015.1091955.
Krishnan SP, Carrington RW, Mohiyaddin S, Garlick N. Common misconceptions of normal hip joint relations on pelvic radiographs. J Arthroplasty. 2006;21:409–12. https://doi.org/10.1016/j.arth.2005.10.021.
Takamatsu T, Shishido T, Takahashi Y, Masaoka T, Tateiwa T, Kubo K, et al. Radiographic determination of hip rotation center and femoral offset in Japanese adults: a preliminary investigation toward the preoperative implications in total hip arthroplasty. BioMed Res Int. 2015;2015:610763. https://doi.org/10.1155/2015/610763.
Flecher X, Ollivier M, Argenson JN. Lower limb length and offset in total hip arthroplasty. Orthop Traumatol Surg Res. 2016;102:S9–20. https://doi.org/10.1016/j.otsr.2015.11.001.
Iorio R, Healy WL, Warren PD, Appleby D. Lateral trochanteric pain following primary total hip arthroplasty. J Arthroplasty. 2006;21:233–6. https://doi.org/10.1016/j.arth.2005.03.041.
Innmann MM, Maier MW, Streit MR, Grammatopoulos G, Bruckner T, Gotterbarm T, et al. Additive influence of hip offset and leg length reconstruction on postoperative improvement in clinical outcome after total hip arthroplasty. J Arthroplasty. 2018;33:156–61. https://doi.org/10.1016/j.arth.2017.08.007.
Sayed-Noor AS, Sjoden GO. Greater trochanteric pain after total hip arthroplasty: the incidence, clinical outcome and associated factors. Hip Int. 2006;16:202–6. https://doi.org/10.5301/hip.2008.4186.
Jameson SS, Lees D, James P, Serrano-Pedraza I, Partington PF, Muller SD, et al. Lower rates of dislocation with increased femoral head size after primary total hip replacement: a five-year analysis of NHS patients in England. J Bone Joint Surg Br. 2011;93:876–80. https://doi.org/10.1302/0301-620X.93B7.26657.
Little NJ, Busch CA, Gallagher JA, Rorabeck CH, Bourne RB. Acetabular polyethylene wear and acetabular inclination and femoral offset. Clin Orthop Relat Res. 2009;467:2895–900. https://doi.org/10.1007/s11999-009-0845-3.
Jingushi S, Ohfuji S, Sofue M, Hirota Y, Itoman M, Matsumoto T, et al. Multiinstitutional epidemiological study regarding osteoarthritis of the hip in Japan. J Orthop Sci. 2010;15:626–31. https://doi.org/10.1007/s00776-010-1507-8.

Table 1

Patient demographics
Characteristic		Value
Number of patients (hips/cases)		283/256
Gender (hips/cases)	Male	68/58
Gender (hips/cases)	Female	215/198
Age at THA^* (years)		63.3 ± 11.1 (33–85)
BMI (kg/m²) ^*		24.5 ± 4.4 (15.8–39.6)
Diagnosis (hips/cases)	OA ONFH FNF RA RDC	216/196 51/44 8/8 3/3 5/5
^* Values are presented as mean ± standard deviation (range)
BMI, body mass index; OA, osteoarthritis; ONFH, osteonecrosis of the femoral head; FNF, femoral neck fracture; RA, rheumatoid arthritis; RDC, rapidly destructive coxopathy; THA, total hip arthroplasty

Table 2

Results of the univariate analysis of factors for dislocation after total hip arthroplasty
Variable		Dislocation (+) n = 9	Dislocation (-) n = 274	p-value
Age at THA^* (years)		61.7 ± 14.2 (40–79)	63.4 ± 11 (33–85)	0.652
Sex (hips/cases)	Male	2/2	66/56	1.000
Sex (hips/cases)	Female	7/7	208/191	1.000
BMI (kg/m²) ^*		25 ± 5.5 (17.2–36.6)	24.5 ± 4.4 (15.8–39.6)	0.722
Mean CA^* (degree)	Widmer	30.4 ± 8.5 (15.1–41.2)	37.1 ± 5.9 (19.8–62.1)	0.001^a
Mean CA^* (degree)	Yoshimine	81.3 ± 12 (60–95)	90.6 ± 7.4 (66.7–118.7)	< 0.001^a
Widmer CA (hips)	Good	2	156	0.0469^a
Widmer CA (hips)	Poor	7	118	0.0469^a
Yoshimine CA (hips)	Good	4	229	0.01^a
Yoshimine CA (hips)	Poor	5	45	0.01^a
Total offset (hips)	Increase (+)	1	168	0.004^a
Total offset (hips)	Decrease (-)	8	106	0.004^a
Acetabular offset (hips)	Increase (+)	2	62	1.000
Acetabular offset (hips)	Decrease (-)	7	212	1.000
Femoral offset (hips)	Increase (+)	6	217	0.406
Femoral offset (hips)	Decrease (-)	3	57	0.406
Total offset D ^* (mm)		-3.5 ± 8.0(-15.9〜12.7)	1.1 ± 8.9 (-31.7〜43.4)	0.124
Acetabular offset D ^* (mm)		-6.1 ± 8.0 (-22.3〜3.2)	-5.1 ± 6.6 (-30.8〜26)	0.67
Femoral offset D ^* (mm)		1.6 ± 5.4 (-4.7〜12.6)	5.3 ± 7.0 (-14.1〜29.9)	0.103^a
^* Values are presented as mean ± standard deviation (range)
^a Statically significant p-value < 0.05
BMI, body mass index; CA, combined anteversion: D, the value obtained by subtracting the preoperative value from the postoperative value for each offset; THA, total hip arthroplasty

Table 3 Dislocation rate of each group of combined anteversion and total offset (dislocated cases/total cases)

3-A Widmer

Widmer	TO decrease	TO increase
CA good	3.2% (2/62)	0% (0/96)
CA poor	11.5% (6/52)	1.4% (1/73)

3-B Yoshimine

Yoshimine	TO decrease	TO increase
CA good	4.8% (4/84)	0% (0/126)
CA poor	20% (4/20)	3.6% (1/28)

CA, combined anteversion: TO, total offset

Table 4

Number of dislocations by femoral head size
		Dislocation (+)	Dislocation (-)	p-value
Femoral head size	≥ 32 mm	6	220	0.392
Femoral head size	< 32mm	3	54	0.392

No competing interests reported.

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Clinical effects of combined anteversion and offset on postoperative dislocation in total hip arthroplasty

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Abstract

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Background

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Surgical procedure and postoperative evaluation

Statistical assessment

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