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Imageless navigation versus traditional method in total hip arthroplasty: A meta-analysis
International Journal of Surgery 21 (2015) 122e127
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Review
Imageless navigation versus traditional method in total hip arthroplasty: A meta-analysis Zhengye Liu a, Yan Gao b, Lin Cai a, * a b
Department of Orthopedics, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430000, PR China Department of Radiology Oncology and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430000, PR China
h i g h l i g h t s Imageless navigation has become more common place, whereas there still exist different arguments about this technique. Mean cup inclination and anteversion were not statistically significantly different with or without this technique. Cup deviation and outliers were significantly decreased with imageless navigation system. Imageless navigation is preferable compared with traditional method.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 17 June 2015 Accepted 18 July 2015 Available online 5 August 2015
Purpose: Accuracy of acetabular component orientation is improved with computer navigation in THA. In recent years, imageless navigation has become more commonplace, whereas there still exist different arguments about this technique. Methods: We conducted a meta-analysis to assess the accuracy of imageless navigation for acetabular implantation in total hip arthroplasty. The computer based online search strategy covered the major medical databases (Cochrane Library, Medline, Pubmed, and EmbaseI) from January 2004 to December 2014. Data of selected clinical trials were analysed using Revman 5.1 software. Results: 7 clinical trials enrolling 485 patients were included. Mean cup inclination and anteversion were not statistically significantly different between the conventional groups and the imageless computer navigated groups (P ¼ 0.83 and P ¼ 0.89 respectively). Deviation from the desired position of inclination shows no significant differences (P ¼ 0.06), whereas deviation from the desired position of anteversion was smaller in computer navigated group (P<0.0001). Only one study gave useful information about operation time which is significantly increased (MD ¼ 23.00, P ¼ 0.001). Conclusions: Current literature generally hold the opinion that navigation is a reliable tool to optimize cup placement, but still there are some different voices about imageless navigation system. This metaanalysis emphasizing more on the accuracy of cup-positioning with imageless navigation reveals that imageless navigation is preferable compared with traditional method. © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Keywords: Total hip arthroplasty Computer navigated Imageless navigation RCTs Meta-analysis
1. Introduction Total hip replacement is commonly used to treat joint failure caused by osteoarthritis. Preventing complications, improving function and durability has been the main focus of arthroplasty research for decades. Dislocation is the most common postoperative complication in total hip arthroplasty. Many factors
* Corresponding author. E-mail addresses: [email protected], [email protected] (L. Cai).
contributes to dislocation, Barrack et al. [1] indicated that deviation in acetabular cup positioning was a major cause of hip dislocations and proposed a safe zone of cup position in 35 e55 of abduction and 10 e30 of anteversion. Lewinnek et al. [2] advocated a “safe zone” of 40 ± 10 of abduction and 15 ± 10 of anteversion. Hereby,a precise placement of the acetabular component in particular is crucial. Traditionally, the acetabular components are placed according to the surgeons' experience and the mechanical alignment guide. In the past decade, the accuracy of these methods has been doubted. Freehand [3,4] and mechanically guided [5e7] techniques have
http://dx.doi.org/10.1016/j.ijsu.2015.07.707 1743-9191/© 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Z. Liu et al. / International Journal of Surgery 21 (2015) 122e127
resulted in inaccurate cup position in terms of inclination and anteversion, with numerous acetabular components placed outside the safe zone defined by Lewinnek et al. [2] even when performed by an experienced surgeon. In this context, computer navigation system was introduced in total hip arthroplasty as a more reliable tool to prevent malpositioning of the prostheses and to ameliorate implant alignment. There now exist three types of navigation systems: computed tomography (CT)-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is in particular outstanding for significantly improved accuracy of orientation of the acetabular component [8], which is, however, outweighed by the relatively longer operation time needed for preoperative planning and the consequent increase in cost and radiation exposure [10]. It is suggested in several studies that imageless navigation, using a three-dimensional optical localizer and an optical tracker mounted to the pelvis to collect anatomical data intraoperatively and to form a three-dimensional reconstruction of a patient's bone, is a highly efficacious technique in achieving optimal cup position and in preventing postoperative dislocation by reducing outliers from the desired position, with the surgery less prolonged and no additional radiation exposure involved. Thus imageless navigation has become more common place in TKA or THA. In spite of all the advantages of imageless navigation, there still exists some argument. Some studies indicated that acetabular component position were similar under tomography analyses after using the imageless navigation or traditional method [11]. A meta-analysis of high quality is quite essential in solving the present problems. There are several meta-analyses [19] comparing computer navigation with traditional method, but none of these articles gave a comparision between imageless navigation and traditional method separately. This study is aimed to compile the current best evidence by pooling all relevant RCT studies comparing imageless navigation and conventional method in THA to examine whether imageless navigation is preferable in regard of cup positioning. 2. Methods and materials Our search strategy covered major electronic databases including Cochrane Library, Medline, Pubmed, and Embase from January 2004 to December 2014. We used the following medical subject headings as key words: “computer navigation”, “computer navigated”, “imageless navigation”, “image-free navigation”, “computer assisted”, each in combination with “total hip arthroplasty”, “total hip replacement”, “THR”, “THA”. We also conducted manual searches in the Journal of Bone and Joint Surgery, and in Google. Reference lists of all identified studies are searched as well for additional relevant trials that the computer-based search may fail to identify. Only English studies conducted on human subjects were included. Including criteria: 1. All published RCTs and quasi-RCTs (in which the method of allocating participants was not strictly random or not mentioned) comparing imageless navigated with the conventional THA. 2. Intervention: Imageless navigation system in experimental group versus traditional manual method in conventional group. 3. Using inclination and anteversion of the cup, Lewinnek's safe zone, operation time as target criteria. Exclusion criteria: Retrospective trials; studies including THA revision or acetabular dysplasia patients; studies in which CTnavigated cases and imageless navigated ones are mixed in the experimental group; not a control study. Full paper of included studies were carefully read and assessed with the following quality criteria including randomization method, concealment of allocation, blinding, data integrity and intention-to-treat analysis. Data was extracted by two authors
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separately. Two authors of this meta-analysis independently extracted all relevant data from eligible studies. Disagreement was resolved by discussion with a third investigator. The following data were extracted:(1) participants' demographic data; (2) mean inclination and anteversion; (3) deviation from desired position of inclination and anteversion; (4) operation time; (5) acetabular components placed outside the desired range; (6) any other outcomes mentioned in individual studies were considered for inclusion. We used chi-square statistics to assess heterogeneity: p-values of <0.1 were considered to indicate statistical heterogeneity, in which condition a random effects model was to be used, otherwise, we used a fixed effects model. We abstracted and calculated weighted means and weighted mean differences, 95% confidence intervals (CIs) for continuous outcomes, Risk ratio (RR) and CIs for dichotomous outcomes. We used the Revman version 5.1 software for all analyses. 3. Results Using our key words, 425 potentially relevant papers were revealed. By screening dates, titles and reading the abstracts and full papers, 7 studies [9e15] involving 485 enrolled patients (240 in the imageless navigation group and 245 in the conventional group) were included in the meta-analysis. The searching process was presented in Fig. 1. Only English studies were included. The sample sizes ranged from 40 to 125. Most of the studies had clear inclusion or exclusion criteria. Most studied referred to the experience of surgeons in conventional THA before the study. All the included trials referred to randomization, but only 4 trials [10,11,12and13] give adequate explanation of allocating methods. And only 1 trial [13] reported allocation concealment. Surgeon blinding is not adaptable; 2 trials referred to blinding of outcome assessment. Details of methodological quality is presented in Table 1. Two of the trials explained the target sample size [10,14]. None of the studied fulfilled the ITT principle. All seven trials gave usable data of cup inclination. For there is a significant heterogeneity (P ¼ 0.0003, I2 ¼ 77%), as is demonstrated in Fig. 2a, a random effects model was used to analyse the data. The weighted mean difference in inclination between conventional and imageless navigation group was not statistically significant (0.2, CI: 1.69e2.09, P ¼ 0.83). Significant heterogeneity (P ¼ 0.001, I2 ¼ 73%) was noted in anteversion as well, Fig. 2b, thus we used a random effects model, no significant difference between the two groups in respect of mean anteversion (0.19, CI: 2.98e2.60, P ¼ 0.89). 3 studies used deviation from the desired position as a criteria [11,12and14], a random effects model was used due to a significant heterogeneity (P ¼ 0.02, I2 ¼ 76%) in deviation from the desired position of inclination, Fig. 2c. Even though without a significant difference between the two groups (1.46, CI: 3.00e0.08, P ¼ 0.06), there is a trend that deviations in experimental group is decreased. After ruling out a study whose result is evidently opposed to the others [11], the decrease has become statistically significant (2.11, CI: 4.06e0.16, P ¼ 0.03). A fixed effects model was used because no statistical heterogeneity (P ¼ 0.3, I2 ¼ 17%) was found in deviation from the desired position of anteversion between the studies, Fig. 2d. Meta-analysis showed a significant difference between the groups in terms of this criteria (2.91, CI: 4.21 to 1.60, P<0.0001). Overall, variability in cup positioning was reduced statistically significantly with imageless navigation. Four studies gave complete data about number of cups implanted beyond safe zone [10,11,13and15]. No statistical heterogeneity (P ¼ 0.64, I2 ¼ 0%) between those studies, Fig. 2e. Relative risk of cup positioning outside the safe zone with navigation was
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Fig. 1. Flow chart of the study selection and inclusion process.
Table 1 Studies included in the meta-analysis. Author
Year
Navigation system
Cup
No. of patients (N/C)
Randomization
ITT
Blinding
Ernst
2011
“randomly allocated”
No
e
2014
Press-fit components (Pinnacle, DePuy, Warsaw, Indiana) Plasmacup, Aesculap
32/30
Henrique M.C Richard Lass
20/20
e
62/63
Randomization criteria used by Excel “randomly assigned”
No
2013
Hip unlimited 5.0; BrainLAB AG, Feldkirchen, Germany. Orthopilot (Aesculap, B. Braun, Tuttlingen, Germany) ORTHOsoft, Inc, Montreal, Canada
No
Assessment blinding
Fang Lin
2011
23/25
“randomized into 2 groups”
No
e
T. Kalteis,
2006
Press-fit (Pinnacle, DePuy, Warsaw, IN)
60/30
“assigned randomly by lot”
No
e
S. Parratte,
2007
Press-fit (Hilock, Symbios)
30/30
Matched pair design
NO
Brian
2009
Not stated
50/55
A sequential series
NO
Assessment blinding e
Stryker Navigation System, Stryker Corp, Kalamazoo, Mich VectorVision hip 3.0 system (BrainLAB,Heimstetten, Germany) Praxim Medivision, Grenoble, France Stryker imageless navigation system.
Cementless titanium conical screw cup (Alloclassic Zweymüller, Zimmer,Inc., Warsaw, IN) Stryker Trident (Stryker Corp)
statistically significantly reduced (RR ¼ 0.31, CI: 0.17e0.55, P<0.0001). Only one study described number of outlier in regards to inclination and anteversion respectively [12]: There were no outliers for inclination in the computer-assisted hips, but 5 outliers (7.9%) of 63 patients in the conventional group (P ¼ 0.02). There were 6 (9.7%) outliers of 62 hips for anteversion in the navigated group, and 23 of 63 (36.5%) in the conventional group (P<0.05). Though only one study gave useful information about operation time which is significantly increased (MD ¼ 23.00, P ¼ 0.001) [15], Fig. 2f. All included studies noted a significant increase of mean operation time in imageless navigated group ranging from 8 min to 23 min. In the study of Kalteis et al., the mean blood loss in the imageless navigated group was 350 mL (20e950 mL), with 399 mL (50e1090 mL) in the conventional group, but no statistically significant difference was found. Overall, variability in cup positioning was statistically significantly reduced with the technique of imageless navigation in THA, along with the risk of placing the acetabular component beyond the
safe zone. 4. Discussion As demonstrated in previous meta-analyses [18,19], accuracy of acetabular component orientation is improved with computer navigation in THA. Considering the fact that imageless navigation system has become more common place in THA whereas none of the previous meta-analyses studied this technique separately, it has become quite necessary to make a high quality meta-analysis emphasizing the accuracy of imageless navigation system. Imageless navigation system has its own advantages when compared with CT-based navigation system: no additional radiation exposure, shorter operation time. But its drawbacks are also obvious in front of CT-base one: relying on cutaneous palpation of bony landmarks to obtain the APP limit the precision of imageless navigation. It is now widely acknowledged that the thickness of the soft tissues over the ASIS (anterior superior iliac spines) can affect the measurement of anteversion or inclination, while the soft
Z. Liu et al. / International Journal of Surgery 21 (2015) 122e127
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Fig. 2. a) Forrest plot for mean inclination of cups placed with and without navigation. b) Forrest plot for mean anteversion of cups placed with and without navigation. c) Forrest plot for deviation from desired position inclination of cups placed with and without navigation. d) Forrest plot for deviation from desired position inclination of cups placed with and without navigation. e) Forrest plot for acetabular component placed beyond safe zone with or without navigation. f) Forrest plot for operation time with or without navigation.
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tissues over the pubic symphysis can affect mainly the anteversion. Thus, acquisition of the APP in obese people doesn't seem to be precise enough [13]. Our meta-analysis demonstrates a clear advantage of imageless navigation system over traditional method in optimizing acetabular alignment in THA. As is proved in other studies, the advantages of navigation systems has always been improved prostheses accuracy and reduced acetabular component outliers, that is, cups positioned beyond the “safe zone”. Lewinnek's definition of safe zone is not universally accepted, but it's still accepted by most surgeons [15,16]. Acetabular component placed beyond the safe zone is believed to be relevant with the dislocation rate [2,17]. It seems that imageless navigation technique meet this criteria in our study, with the deviation from desired position of inclination and anteversion decreased significantly. The significant difference in acetabular component position and outliers between the two groups, is of great clinical value, as in the condition of malposition, the acetabular component may experience more impingement and the range of motion is restricted. It is now known as a risk factor for dislocation and is considered to be relevant with increased and premature wear, elevated blood metalion concentrations, loosening and revision of the prosthesis [20e22]. It is something that all surgeons strive to avoid using a variety of techniques including computer navigation. However, this proven advantage of CT-base navigation, accuracy, is traded off against the argument of prolonged operative time, higher costs and radiation exposure. By contrast, imageless navigation is equally effective in reducing outliers with the surgery time less prolonged and no additional radiation exposure involved. Even though in our study operation time is significantly increased in the imageless group as well, more studies with long time follow up are needed to see if the additional operation time are able to cause relevant complications and affect long-term outcomes. In conclusion, imageless navigation do improve the accuracy of acetabular placement in terms of decreasing the deviation of acetabular component [23]. In expense, operation time have significantly augmented, whose influence on long-term outcome is still not quite clear. Both advantages and disadvantages should be taken into consideration when making clinical decisions. It is very important to guarantee the accuracy of registration of the anatomical landmarks in order to obtain an accurate position of the anterior pelvic plane by the computer. Richard Lass et al. recommended one method of using a sharp metal pointer to get the registration of the anatomical landmarks [12]. They believed that it may help to achieve a high accuracy even in obese patients and found no significant difference in implantation accuracy in regard to patients with a BMI <27 kg/m2 or 27 kg/m2. More studies of high quality are needed to further prove our results. Furthermore, weaknesses in methodology of these included trials are not negligible as well. Future trials must adhere to methodological standards such as proper random assignment and intention-to-treat analyses, and aim for a thorough comparison of radiographic and functional results, complication and survival rates, quality of life, and also extra costs and cost utility.
Ethical approval No Ethical Approval was given.
Funding None.
Author contribution Cailin: study design. Liu Zhengye&Gao yan: data collection, data analysis. Liu Zhengye: writing. Conflict of interest statement None to declare. Guarantor Liu Zhengye. References [1] R. Barrack, Dislocation after total hip arthroplasty: implant design and orientation, J. Am. Acad. Orthop. Surg. 11 (2003) 89. [2] G.E. Lewinnek, J.L. Lewis, R. Tarr, Dislocations after totalhip replacement arthroplasties, J. Bone Jt. Surg. 60A (1978) 217. [3] T. Leenders, D. Vandevelde, G. Mahieu, et al., Reduction in variability of acetabular cup abduction using computer assisted surgery: a prospective and randomized study, Comput. Aided Surg. 7e2 (2002) 99. [4] G. Saxler, A. Marx, D. Vandevelde, U. Langlotz, M. Tannast, M. Wiese, U. Michaelis, G. Kemper, P.A. Grützner, R. Steffen, M. von Knoch, T. HollandLetz, K. Bernsmann, The accuracy of free-hand cup positioningda CT based measurement of cup placement in 105 total hip arthroplasties, Int. Orthop. 28e4 (2004) 198. [5] A.M. Digioia 3rd, B. Jaramaz, A.Y. Plakseychuk, J.E. Moody Jr., C. Nikou, R.S. Labarca, T.J. Levison, F. Picard, Comparison of a mechanical acetabular alignment guide with computer placement of the socket, J. Arthroplast. 17e3 (2002) 359. [6] D.M. Hassan, G.H. Johnston, W.N. Dust, G. Watson, A.T. Dolovich, Accuracy of intraoperative assessment of acetabular prosthesis placement, J. Arthroplast. 13e1 (1998) 80. [7] M. Nogler, O. Kessler, A. Prassl, B. Donnelly, R. Streicher, J.B. Sledge, M. Krismer, Reduced variability of acetabular cup positioning with use of an imageless navigation system, Clin. Orthop. Relat. Res. 426 (2004) 159. [8] A.M. DiGioia, B. Jaramaz, M. Blackwell, D.A. Simon, F. Morgan, J.E. Moody, C. Nikou, B.D. Colgan, C.A. Aston, R.S. Labarca, E. Kischell, T. Kanade, The Otto Aufranc Award: image guided navigation system to measure intraoperatively acetabular implant alignment, Clin. Orthop. 355 (1998) 8e22. €rner, T. Kalteis, J. Grifka, T. Renkawitz, Accuracy [9] E. Sendtner, T. Schuster, M. Wo of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position, Int. Orthop. (SICOT) 35 (2011) 809e815. €this, L. Perlick, M. Tingart, J. Grifka, Imageless [10] T. Kalteis, M. Handel, H. Ba navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation? J. Bone Jt. Surg. Br. 88 (2) (2006) 163e167. [11] H.M. Gurgel, A.T. Croci, H.A. Cabrita, J.R. Vicente, M.C. Leonhardt, J.C. Rodrigues, Acetabular component positioning in total hip arthroplasty with and without a computer-assisted system_ a prospective, randomized and controlled study, J. Arthroplast. 29 (2014) 167e171. [12] R. Lass, B. Kubista, B. Olischar, S. Frantal, R. Windhager, A. Giurea, Total hip arthroplasty using imageless computer-assisted hip navigation. A prospective randomized study, J. Arthroplast. 29 (2014) 786e791. [13] S. Parratte, J.N. Argenson, Validation and usefulness of a computer-assisted cup-positioning system in total hip arthroplasty. A prospective, randomized, controlled study, J. Bone Jt. Surg. Am. 89 (2007) 494e499, http://dx.doi.org/ 10.2106/JBJS.F.00529. [14] Lin F1, D. Lim, R.L. Wixson, S. Milos, R.W. Hendrix, M. Makhsous, Limitations of imageless computer-assisted navigation for total hip arthroplasty, J. Arthroplast. 26 (4) (2011). [15] B.C. Najarian, J.E. Kilgore, D.C. Markel, Evaluation of component positioning in primary total hip arthroplasty using an imageless navigation device compared with traditional methods, J. Arthroplast. 24 (1) (2009). [16] I.H. Reininga, W. Zijlstra, R. Wagenmakers, et al., Minimally invasive and computer navigated total hip arthroplasty: a qualitative and systematic review of the literature, BMC Muscoloskelet Disord. 11 (2010) 92. [17] K. Hirakawa, N. Mitsugi, T. Koshino, T. Saito, Y. Hirasawa, T. Kubo, Effect of acetabular cup position and orientation in cemented total hip arthroplasty, Clin. Orthop. Relat. Res. 388 (2001) 135e142. [18] K. Xu, Y.M. Li, H.F. Zhang, C.G. Wang, Y.Q. Xu, Z.J. Li, Computer navigation in total hip arthroplasty: a meta-analysis of randomized controlled trials, Int. J. Surg. 12 (2014) 528e533. €tz, J. Grifka, C. Lüring, Navigated cup [19] J. Beckmann, D. Stengel, M. Tingart, J. Go implantation in hip arthroplasty. A meta-analysis, Acta Orthop. 80 (5) (2009) 538e544. [20] S. Patil, A. Bergula, P.C. Chen, C.W. Colwell Jr., D.D. D'Lima, Polyethylene wear and acetabular component orientation, J. Bone Jt. Surg. Am. 85 (Suppl. 4)
Z. Liu et al. / International Journal of Surgery 21 (2015) 122e127 (2003) 56e63. [21] T. Nishii, N. Sugano, H. Miki, T. Koyama, M. Takao, H. Yoshikawa, Influence of component positions on dislocation: computed tomographic evaluations in a consecutive series of total hip arthroplasty, J. Arthroplast. 19 (2004) 162e166. [22] W. Brodner, A. Grubl, R. Jankovsky, V. Meisinger, S. Lehr, F. Gottsauner-Wolf, Cup inclination and serum concentration of cobalt and chromium after metal-
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on-metal total hip arthroplasty, J. Arthroplast. 19 (2004) 66e70. [23] C. Merle, G. Grammatopoulos, W. Waldstein, E. Pegg, H. Pandit, P.R. Aldinger, H.S. Gill, D.W. Murray, Comparison of native anatomy with recommended safe component orientation in total hip arthroplasty for primary osteoarthritis, J. Bone Jt. Surg. Am. 95 (22) (2013 Nov 20) e172, http://dx.doi.org/10.2106/ JBJS.L.01014.
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Review
Imageless navigation versus traditional method in total hip arthroplasty: A meta-analysis Zhengye Liu a, Yan Gao b, Lin Cai a, * a b
Department of Orthopedics, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430000, PR China Department of Radiology Oncology and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430000, PR China
h i g h l i g h t s Imageless navigation has become more common place, whereas there still exist different arguments about this technique. Mean cup inclination and anteversion were not statistically significantly different with or without this technique. Cup deviation and outliers were significantly decreased with imageless navigation system. Imageless navigation is preferable compared with traditional method.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 17 June 2015 Accepted 18 July 2015 Available online 5 August 2015
Purpose: Accuracy of acetabular component orientation is improved with computer navigation in THA. In recent years, imageless navigation has become more commonplace, whereas there still exist different arguments about this technique. Methods: We conducted a meta-analysis to assess the accuracy of imageless navigation for acetabular implantation in total hip arthroplasty. The computer based online search strategy covered the major medical databases (Cochrane Library, Medline, Pubmed, and EmbaseI) from January 2004 to December 2014. Data of selected clinical trials were analysed using Revman 5.1 software. Results: 7 clinical trials enrolling 485 patients were included. Mean cup inclination and anteversion were not statistically significantly different between the conventional groups and the imageless computer navigated groups (P ¼ 0.83 and P ¼ 0.89 respectively). Deviation from the desired position of inclination shows no significant differences (P ¼ 0.06), whereas deviation from the desired position of anteversion was smaller in computer navigated group (P<0.0001). Only one study gave useful information about operation time which is significantly increased (MD ¼ 23.00, P ¼ 0.001). Conclusions: Current literature generally hold the opinion that navigation is a reliable tool to optimize cup placement, but still there are some different voices about imageless navigation system. This metaanalysis emphasizing more on the accuracy of cup-positioning with imageless navigation reveals that imageless navigation is preferable compared with traditional method. © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Keywords: Total hip arthroplasty Computer navigated Imageless navigation RCTs Meta-analysis
1. Introduction Total hip replacement is commonly used to treat joint failure caused by osteoarthritis. Preventing complications, improving function and durability has been the main focus of arthroplasty research for decades. Dislocation is the most common postoperative complication in total hip arthroplasty. Many factors
* Corresponding author. E-mail addresses: [email protected], [email protected] (L. Cai).
contributes to dislocation, Barrack et al. [1] indicated that deviation in acetabular cup positioning was a major cause of hip dislocations and proposed a safe zone of cup position in 35 e55 of abduction and 10 e30 of anteversion. Lewinnek et al. [2] advocated a “safe zone” of 40 ± 10 of abduction and 15 ± 10 of anteversion. Hereby,a precise placement of the acetabular component in particular is crucial. Traditionally, the acetabular components are placed according to the surgeons' experience and the mechanical alignment guide. In the past decade, the accuracy of these methods has been doubted. Freehand [3,4] and mechanically guided [5e7] techniques have
http://dx.doi.org/10.1016/j.ijsu.2015.07.707 1743-9191/© 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Z. Liu et al. / International Journal of Surgery 21 (2015) 122e127
resulted in inaccurate cup position in terms of inclination and anteversion, with numerous acetabular components placed outside the safe zone defined by Lewinnek et al. [2] even when performed by an experienced surgeon. In this context, computer navigation system was introduced in total hip arthroplasty as a more reliable tool to prevent malpositioning of the prostheses and to ameliorate implant alignment. There now exist three types of navigation systems: computed tomography (CT)-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is in particular outstanding for significantly improved accuracy of orientation of the acetabular component [8], which is, however, outweighed by the relatively longer operation time needed for preoperative planning and the consequent increase in cost and radiation exposure [10]. It is suggested in several studies that imageless navigation, using a three-dimensional optical localizer and an optical tracker mounted to the pelvis to collect anatomical data intraoperatively and to form a three-dimensional reconstruction of a patient's bone, is a highly efficacious technique in achieving optimal cup position and in preventing postoperative dislocation by reducing outliers from the desired position, with the surgery less prolonged and no additional radiation exposure involved. Thus imageless navigation has become more common place in TKA or THA. In spite of all the advantages of imageless navigation, there still exists some argument. Some studies indicated that acetabular component position were similar under tomography analyses after using the imageless navigation or traditional method [11]. A meta-analysis of high quality is quite essential in solving the present problems. There are several meta-analyses [19] comparing computer navigation with traditional method, but none of these articles gave a comparision between imageless navigation and traditional method separately. This study is aimed to compile the current best evidence by pooling all relevant RCT studies comparing imageless navigation and conventional method in THA to examine whether imageless navigation is preferable in regard of cup positioning. 2. Methods and materials Our search strategy covered major electronic databases including Cochrane Library, Medline, Pubmed, and Embase from January 2004 to December 2014. We used the following medical subject headings as key words: “computer navigation”, “computer navigated”, “imageless navigation”, “image-free navigation”, “computer assisted”, each in combination with “total hip arthroplasty”, “total hip replacement”, “THR”, “THA”. We also conducted manual searches in the Journal of Bone and Joint Surgery, and in Google. Reference lists of all identified studies are searched as well for additional relevant trials that the computer-based search may fail to identify. Only English studies conducted on human subjects were included. Including criteria: 1. All published RCTs and quasi-RCTs (in which the method of allocating participants was not strictly random or not mentioned) comparing imageless navigated with the conventional THA. 2. Intervention: Imageless navigation system in experimental group versus traditional manual method in conventional group. 3. Using inclination and anteversion of the cup, Lewinnek's safe zone, operation time as target criteria. Exclusion criteria: Retrospective trials; studies including THA revision or acetabular dysplasia patients; studies in which CTnavigated cases and imageless navigated ones are mixed in the experimental group; not a control study. Full paper of included studies were carefully read and assessed with the following quality criteria including randomization method, concealment of allocation, blinding, data integrity and intention-to-treat analysis. Data was extracted by two authors
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separately. Two authors of this meta-analysis independently extracted all relevant data from eligible studies. Disagreement was resolved by discussion with a third investigator. The following data were extracted:(1) participants' demographic data; (2) mean inclination and anteversion; (3) deviation from desired position of inclination and anteversion; (4) operation time; (5) acetabular components placed outside the desired range; (6) any other outcomes mentioned in individual studies were considered for inclusion. We used chi-square statistics to assess heterogeneity: p-values of <0.1 were considered to indicate statistical heterogeneity, in which condition a random effects model was to be used, otherwise, we used a fixed effects model. We abstracted and calculated weighted means and weighted mean differences, 95% confidence intervals (CIs) for continuous outcomes, Risk ratio (RR) and CIs for dichotomous outcomes. We used the Revman version 5.1 software for all analyses. 3. Results Using our key words, 425 potentially relevant papers were revealed. By screening dates, titles and reading the abstracts and full papers, 7 studies [9e15] involving 485 enrolled patients (240 in the imageless navigation group and 245 in the conventional group) were included in the meta-analysis. The searching process was presented in Fig. 1. Only English studies were included. The sample sizes ranged from 40 to 125. Most of the studies had clear inclusion or exclusion criteria. Most studied referred to the experience of surgeons in conventional THA before the study. All the included trials referred to randomization, but only 4 trials [10,11,12and13] give adequate explanation of allocating methods. And only 1 trial [13] reported allocation concealment. Surgeon blinding is not adaptable; 2 trials referred to blinding of outcome assessment. Details of methodological quality is presented in Table 1. Two of the trials explained the target sample size [10,14]. None of the studied fulfilled the ITT principle. All seven trials gave usable data of cup inclination. For there is a significant heterogeneity (P ¼ 0.0003, I2 ¼ 77%), as is demonstrated in Fig. 2a, a random effects model was used to analyse the data. The weighted mean difference in inclination between conventional and imageless navigation group was not statistically significant (0.2, CI: 1.69e2.09, P ¼ 0.83). Significant heterogeneity (P ¼ 0.001, I2 ¼ 73%) was noted in anteversion as well, Fig. 2b, thus we used a random effects model, no significant difference between the two groups in respect of mean anteversion (0.19, CI: 2.98e2.60, P ¼ 0.89). 3 studies used deviation from the desired position as a criteria [11,12and14], a random effects model was used due to a significant heterogeneity (P ¼ 0.02, I2 ¼ 76%) in deviation from the desired position of inclination, Fig. 2c. Even though without a significant difference between the two groups (1.46, CI: 3.00e0.08, P ¼ 0.06), there is a trend that deviations in experimental group is decreased. After ruling out a study whose result is evidently opposed to the others [11], the decrease has become statistically significant (2.11, CI: 4.06e0.16, P ¼ 0.03). A fixed effects model was used because no statistical heterogeneity (P ¼ 0.3, I2 ¼ 17%) was found in deviation from the desired position of anteversion between the studies, Fig. 2d. Meta-analysis showed a significant difference between the groups in terms of this criteria (2.91, CI: 4.21 to 1.60, P<0.0001). Overall, variability in cup positioning was reduced statistically significantly with imageless navigation. Four studies gave complete data about number of cups implanted beyond safe zone [10,11,13and15]. No statistical heterogeneity (P ¼ 0.64, I2 ¼ 0%) between those studies, Fig. 2e. Relative risk of cup positioning outside the safe zone with navigation was
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Fig. 1. Flow chart of the study selection and inclusion process.
Table 1 Studies included in the meta-analysis. Author
Year
Navigation system
Cup
No. of patients (N/C)
Randomization
ITT
Blinding
Ernst
2011
“randomly allocated”
No
e
2014
Press-fit components (Pinnacle, DePuy, Warsaw, Indiana) Plasmacup, Aesculap
32/30
Henrique M.C Richard Lass
20/20
e
62/63
Randomization criteria used by Excel “randomly assigned”
No
2013
Hip unlimited 5.0; BrainLAB AG, Feldkirchen, Germany. Orthopilot (Aesculap, B. Braun, Tuttlingen, Germany) ORTHOsoft, Inc, Montreal, Canada
No
Assessment blinding
Fang Lin
2011
23/25
“randomized into 2 groups”
No
e
T. Kalteis,
2006
Press-fit (Pinnacle, DePuy, Warsaw, IN)
60/30
“assigned randomly by lot”
No
e
S. Parratte,
2007
Press-fit (Hilock, Symbios)
30/30
Matched pair design
NO
Brian
2009
Not stated
50/55
A sequential series
NO
Assessment blinding e
Stryker Navigation System, Stryker Corp, Kalamazoo, Mich VectorVision hip 3.0 system (BrainLAB,Heimstetten, Germany) Praxim Medivision, Grenoble, France Stryker imageless navigation system.
Cementless titanium conical screw cup (Alloclassic Zweymüller, Zimmer,Inc., Warsaw, IN) Stryker Trident (Stryker Corp)
statistically significantly reduced (RR ¼ 0.31, CI: 0.17e0.55, P<0.0001). Only one study described number of outlier in regards to inclination and anteversion respectively [12]: There were no outliers for inclination in the computer-assisted hips, but 5 outliers (7.9%) of 63 patients in the conventional group (P ¼ 0.02). There were 6 (9.7%) outliers of 62 hips for anteversion in the navigated group, and 23 of 63 (36.5%) in the conventional group (P<0.05). Though only one study gave useful information about operation time which is significantly increased (MD ¼ 23.00, P ¼ 0.001) [15], Fig. 2f. All included studies noted a significant increase of mean operation time in imageless navigated group ranging from 8 min to 23 min. In the study of Kalteis et al., the mean blood loss in the imageless navigated group was 350 mL (20e950 mL), with 399 mL (50e1090 mL) in the conventional group, but no statistically significant difference was found. Overall, variability in cup positioning was statistically significantly reduced with the technique of imageless navigation in THA, along with the risk of placing the acetabular component beyond the
safe zone. 4. Discussion As demonstrated in previous meta-analyses [18,19], accuracy of acetabular component orientation is improved with computer navigation in THA. Considering the fact that imageless navigation system has become more common place in THA whereas none of the previous meta-analyses studied this technique separately, it has become quite necessary to make a high quality meta-analysis emphasizing the accuracy of imageless navigation system. Imageless navigation system has its own advantages when compared with CT-based navigation system: no additional radiation exposure, shorter operation time. But its drawbacks are also obvious in front of CT-base one: relying on cutaneous palpation of bony landmarks to obtain the APP limit the precision of imageless navigation. It is now widely acknowledged that the thickness of the soft tissues over the ASIS (anterior superior iliac spines) can affect the measurement of anteversion or inclination, while the soft
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Fig. 2. a) Forrest plot for mean inclination of cups placed with and without navigation. b) Forrest plot for mean anteversion of cups placed with and without navigation. c) Forrest plot for deviation from desired position inclination of cups placed with and without navigation. d) Forrest plot for deviation from desired position inclination of cups placed with and without navigation. e) Forrest plot for acetabular component placed beyond safe zone with or without navigation. f) Forrest plot for operation time with or without navigation.
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tissues over the pubic symphysis can affect mainly the anteversion. Thus, acquisition of the APP in obese people doesn't seem to be precise enough [13]. Our meta-analysis demonstrates a clear advantage of imageless navigation system over traditional method in optimizing acetabular alignment in THA. As is proved in other studies, the advantages of navigation systems has always been improved prostheses accuracy and reduced acetabular component outliers, that is, cups positioned beyond the “safe zone”. Lewinnek's definition of safe zone is not universally accepted, but it's still accepted by most surgeons [15,16]. Acetabular component placed beyond the safe zone is believed to be relevant with the dislocation rate [2,17]. It seems that imageless navigation technique meet this criteria in our study, with the deviation from desired position of inclination and anteversion decreased significantly. The significant difference in acetabular component position and outliers between the two groups, is of great clinical value, as in the condition of malposition, the acetabular component may experience more impingement and the range of motion is restricted. It is now known as a risk factor for dislocation and is considered to be relevant with increased and premature wear, elevated blood metalion concentrations, loosening and revision of the prosthesis [20e22]. It is something that all surgeons strive to avoid using a variety of techniques including computer navigation. However, this proven advantage of CT-base navigation, accuracy, is traded off against the argument of prolonged operative time, higher costs and radiation exposure. By contrast, imageless navigation is equally effective in reducing outliers with the surgery time less prolonged and no additional radiation exposure involved. Even though in our study operation time is significantly increased in the imageless group as well, more studies with long time follow up are needed to see if the additional operation time are able to cause relevant complications and affect long-term outcomes. In conclusion, imageless navigation do improve the accuracy of acetabular placement in terms of decreasing the deviation of acetabular component [23]. In expense, operation time have significantly augmented, whose influence on long-term outcome is still not quite clear. Both advantages and disadvantages should be taken into consideration when making clinical decisions. It is very important to guarantee the accuracy of registration of the anatomical landmarks in order to obtain an accurate position of the anterior pelvic plane by the computer. Richard Lass et al. recommended one method of using a sharp metal pointer to get the registration of the anatomical landmarks [12]. They believed that it may help to achieve a high accuracy even in obese patients and found no significant difference in implantation accuracy in regard to patients with a BMI <27 kg/m2 or 27 kg/m2. More studies of high quality are needed to further prove our results. Furthermore, weaknesses in methodology of these included trials are not negligible as well. Future trials must adhere to methodological standards such as proper random assignment and intention-to-treat analyses, and aim for a thorough comparison of radiographic and functional results, complication and survival rates, quality of life, and also extra costs and cost utility.
Ethical approval No Ethical Approval was given.
Funding None.
Author contribution Cailin: study design. Liu Zhengye&Gao yan: data collection, data analysis. Liu Zhengye: writing. Conflict of interest statement None to declare. Guarantor Liu Zhengye. References [1] R. Barrack, Dislocation after total hip arthroplasty: implant design and orientation, J. Am. Acad. Orthop. Surg. 11 (2003) 89. [2] G.E. Lewinnek, J.L. Lewis, R. Tarr, Dislocations after totalhip replacement arthroplasties, J. Bone Jt. Surg. 60A (1978) 217. [3] T. Leenders, D. Vandevelde, G. Mahieu, et al., Reduction in variability of acetabular cup abduction using computer assisted surgery: a prospective and randomized study, Comput. Aided Surg. 7e2 (2002) 99. [4] G. Saxler, A. Marx, D. Vandevelde, U. Langlotz, M. Tannast, M. Wiese, U. Michaelis, G. Kemper, P.A. Grützner, R. Steffen, M. von Knoch, T. HollandLetz, K. Bernsmann, The accuracy of free-hand cup positioningda CT based measurement of cup placement in 105 total hip arthroplasties, Int. Orthop. 28e4 (2004) 198. [5] A.M. Digioia 3rd, B. Jaramaz, A.Y. Plakseychuk, J.E. Moody Jr., C. Nikou, R.S. Labarca, T.J. Levison, F. Picard, Comparison of a mechanical acetabular alignment guide with computer placement of the socket, J. Arthroplast. 17e3 (2002) 359. [6] D.M. Hassan, G.H. Johnston, W.N. Dust, G. Watson, A.T. Dolovich, Accuracy of intraoperative assessment of acetabular prosthesis placement, J. Arthroplast. 13e1 (1998) 80. [7] M. Nogler, O. Kessler, A. Prassl, B. Donnelly, R. Streicher, J.B. Sledge, M. Krismer, Reduced variability of acetabular cup positioning with use of an imageless navigation system, Clin. Orthop. Relat. Res. 426 (2004) 159. [8] A.M. DiGioia, B. Jaramaz, M. Blackwell, D.A. Simon, F. Morgan, J.E. Moody, C. Nikou, B.D. Colgan, C.A. Aston, R.S. Labarca, E. Kischell, T. Kanade, The Otto Aufranc Award: image guided navigation system to measure intraoperatively acetabular implant alignment, Clin. Orthop. 355 (1998) 8e22. €rner, T. Kalteis, J. Grifka, T. Renkawitz, Accuracy [9] E. Sendtner, T. Schuster, M. Wo of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position, Int. Orthop. (SICOT) 35 (2011) 809e815. €this, L. Perlick, M. Tingart, J. Grifka, Imageless [10] T. Kalteis, M. Handel, H. Ba navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation? J. Bone Jt. Surg. Br. 88 (2) (2006) 163e167. [11] H.M. Gurgel, A.T. Croci, H.A. Cabrita, J.R. Vicente, M.C. Leonhardt, J.C. Rodrigues, Acetabular component positioning in total hip arthroplasty with and without a computer-assisted system_ a prospective, randomized and controlled study, J. Arthroplast. 29 (2014) 167e171. [12] R. Lass, B. Kubista, B. Olischar, S. Frantal, R. Windhager, A. Giurea, Total hip arthroplasty using imageless computer-assisted hip navigation. A prospective randomized study, J. Arthroplast. 29 (2014) 786e791. [13] S. Parratte, J.N. Argenson, Validation and usefulness of a computer-assisted cup-positioning system in total hip arthroplasty. A prospective, randomized, controlled study, J. Bone Jt. Surg. Am. 89 (2007) 494e499, http://dx.doi.org/ 10.2106/JBJS.F.00529. [14] Lin F1, D. Lim, R.L. Wixson, S. Milos, R.W. Hendrix, M. Makhsous, Limitations of imageless computer-assisted navigation for total hip arthroplasty, J. Arthroplast. 26 (4) (2011). [15] B.C. Najarian, J.E. Kilgore, D.C. Markel, Evaluation of component positioning in primary total hip arthroplasty using an imageless navigation device compared with traditional methods, J. Arthroplast. 24 (1) (2009). [16] I.H. Reininga, W. Zijlstra, R. Wagenmakers, et al., Minimally invasive and computer navigated total hip arthroplasty: a qualitative and systematic review of the literature, BMC Muscoloskelet Disord. 11 (2010) 92. [17] K. Hirakawa, N. Mitsugi, T. Koshino, T. Saito, Y. Hirasawa, T. Kubo, Effect of acetabular cup position and orientation in cemented total hip arthroplasty, Clin. Orthop. Relat. Res. 388 (2001) 135e142. [18] K. Xu, Y.M. Li, H.F. Zhang, C.G. Wang, Y.Q. Xu, Z.J. Li, Computer navigation in total hip arthroplasty: a meta-analysis of randomized controlled trials, Int. J. Surg. 12 (2014) 528e533. €tz, J. Grifka, C. Lüring, Navigated cup [19] J. Beckmann, D. Stengel, M. Tingart, J. Go implantation in hip arthroplasty. A meta-analysis, Acta Orthop. 80 (5) (2009) 538e544. [20] S. Patil, A. Bergula, P.C. Chen, C.W. Colwell Jr., D.D. D'Lima, Polyethylene wear and acetabular component orientation, J. Bone Jt. Surg. Am. 85 (Suppl. 4)
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