The Open Orthopaedics Journal




ISSN: 1874-3250 ― Volume 13, 2019

Acetabular Component Anteversion in Primary and Revision Total Hip Arthroplasty: An Observational Study



Olav Reikerås*, 1, Ragnhild B. Gunderson2
1 Orthopaedic Departement,
2 Radiological Department, Oslo University Hospital, Rikshospitalet, N-0027 Oslo, Norway

Abstract

Purpose:

In a prospective manner to evaluate the range of acetabular component anteversion actually achieved by the use of a cup positioner in cementless revision and primary THA.

Methods:

We operated 71 patients with cementless primary THA, and 26 patients with cementless acetabular revision surgery. We aimed to obtain cup anteversion of 10 to 30° with an impactor-positioner. In all cases we used elevated liners and a ceramic head with diameter 28. At 3 months postoperatively the component versions were measured using CT with the patient in supine position.

Results:

The acetabular component version in the primary hips ranged from 28° of retroversion to 42° of anteversion with a mean of 17.4 ± 14.0°, while the cup version in the revision hips ranged from 4° of retroversion to 32° of anteversion with a mean of 15.0 ± 9.6°(p=0.427). The anteversion of 40 (56%) of the primary acetabular components were within the target zone of 10 to 30°, while 19 (27%) were below the target zone and and 12 (17%) were above the target range. The anteversion of 19 (73%) of the revision acetabular components were within the target zone, while 6 (23%) were below the target zone and 1 (4%) were above the target range. The differences in distribution between the primary and revision operations were not significant (p=0.183).

Conclusions:

The intraoperative estimation of acetabular anteversion by free hand technique in many cases was not within the intended range of 10 to 30° in either primary or revision THA and with no differences between the two series

Keywords: Anteversion, acetabular component, arthroplasty, CT, revision.


Article Information


Identifiers and Pagination:

Year: 2013
Volume: 7
First Page: 600
Last Page: 604
Publisher Id: TOORTHJ-7-600
DOI: 10.2174/1874325001307010600

Article History:

Received Date: 5/3/2013
Revision Received Date: 18/6/2013
Acceptance Date: 23/6/2013
Electronic publication date: 4 /10/2013
Collection year: 2013

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 2163
Abstract HTML Views: 967
PDF Downloads: 302
Total Views/Downloads: 3432

Unique Statistics:

Full-Text HTML Views: 1036
Abstract HTML Views: 599
PDF Downloads: 211
Total Views/Downloads: 1846
Geographical View

© Reikerås and Gunderson; Licensee Bentham Open.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.5/) which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.


* Address correspondence to this author at the Orthopaedic Departement, Oslo University Hospital, Rikshospitalet, N-0027 Oslo, Norway; Tel: +4723076010; Fax: +47 23076013; E-mail: olav.reikeras@rikshospitalet.no





INTRODUCTION

Appropriate orientation of the acetabular cup is an important determinant to achieve adequate range of motion and stability in total hip arthroplasty (THA). Malpositioning has been associated with impingement, dislocation, accelerated polyethylene wear, pelvic osteolysis, component loosening and migration [1Kennedy JG, Rogers WB, Soffe KE, et al. Effect of acetabular component orientation on recurrent dislocation. pelvic osteoysis polyethylene wear, and component migration. J Arthroplasty 1998; 13: 530-4.-4Wan Z, Boutary M, Dorr LD. The influence of acetabular component position on wear in total hip arthroplasty. J Arthroplasty 2008; 23: 51-6.]. Generally, cup positioning is performed with the use of mechanical guides, but as intraoperative pelvic positioning varies, especially in the lateral position [5Asayama I, Akiyoshi Y, Naito M, Ezoe M. Intraoperative pelvic motion in total hip arthroplasty. J Arthroplasty 2004; 19: 992-7.] these techniques often result in inaccurate cup anteversion with cups placed outside the predefined safe zone as described by Lewinnek et al. (i.e. anteversion of 15 ± 10°) [6Lewinnek GE, Lewis JL, Tarr R, et al. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 1978; 60: 217-0.-12Najarian BC, Kilgore JE, Markel DC. Evaluation of component positioning in primary total hip arthroplasty using an imageless navigation device compared to traditional methods. J Arthroplasty 2009; 24: 15-21.].

In revision surgery loss of bone stock can make reconstruction of the failed acetabular component challenging, and intraoperative landmarks that are mandatory for appropriate cup orientation may be deteriorated. However, there is no published information about acetabular component orientation with freehand techniques in revision surgery of the failed acetabular component. Furthermore, no studies have compared cup anteversion in revision with primary THA surgery.

In this observational study we obtained CT scans postoperatively with the patient in supine position to measure the version of the acetabular component in patients who underwent revision and primary THA to answer what is the range of cup anteversion actually achieved in revision surgery to clarify whether there are differences in revision as compared to primary cases of THA. Our null hypothesis was that there are no differences in acetabular component version between primary and revision THA with the use of a cup positioner with an alignment frame.

PATIENTS AND METHODS

The study was approved by the local ethical committee and performed in accordance with the ethical standards of the 1964 Declaration of Helsinki as revised in 2000. It was prospectively performed in 97 patients (97 hips). Seventy-one patients (48 women and 23 men) aged 45 to 90 (mean 65) years underwent cementless primary THA, and 26 patients (19 women and 7 men) aged 47 to 81 (mean 70) years underwent cementless acetabular revision surgery 8 to 16 years after primary THA. The patients were operated during the year 2008, and they were consecutively enrolled in the study. In revision surgery we intend to obtain at least 50% contact between a cementless cup and host bone, and if the preferable version was not possible because of major acetabular defects as judged by the surgeon, we had to compromise between the preferred version and bone contact of the cup, and these cases were excluded from the study, which left 26 revision patients to be included.

Five senior surgeons at our hospital operated the patients, and they were all informed of the study. The operations were performed with the patients in the lateral position, using a standardized lateral or posterior approach. In all cases we used a porous coated hemispherical press fit cup (Trilogy, Zimmer, Warsaw, In, USA), and we aimed to obtain acetabular antversion of 10 to 30° using a cup positioner with an alignment connector and frame provided with the implant. This is designed to obtain 20° of anteversion if the alignment rod is in line with the longitudinal axis of the patient. In all the primary cases we obtained press fit stabilization of the implant shell, while it is our routine to secure the implant shell with 2-3 screws in revision cases (Figs. 1, 2). We used elevated liners to provide optimal femoral head coverage, and we used ceramic heads with a diameter of 28 mm.

Fig. (1)

Failed acetabular component.



Fig. (2)

Revision of the failed acetabular component.



At 3 months postoperatively, and after informed consent in all patients, acetabular and femoral component version was measured using CT (General Electric LightSpeed Pro 16 Milwaukee, Wi, USA). Single scans, 5 mm of thickness, were made through the centre of the femoral head, and we defined acetabular component version as the angle between a line connecting the lateral anterior and posterior margins of the acetabular component and the coronal plane defined as the plane perpendicular to a line connecting 2 identical points on either side of the pelvis (Fig. 3). The same specialist in radiology made all assessments.

Fig. (3)

Anteversion of the revised acetabular component defined as the angle between a line connecting lateral anterior and posterior margins of the component and the sagittal plane defined as the plane perpendicular to a line connecting two identical points on either side of the pelvis.



Descriptive statistics is mean, standard deviation, 95% confidence interval (CI) and ranges. Differences between groups were tested using a two-sample t-test. P<0.05 was considered significant. Power analyses were not performed because aiming of cup position as well as results are differently described in the literature and there are no data on cup positioning in revision THA. Thus, power calculations would be questionable.

RESULTS

The acetabular component version in the primary hips as measured from the CT scan ranged from 28° of retroversion to 42° of anteversion with a mean of 17.4 ± 14.0° (CI 14.1°, 20.7°), while the cup version in the revision hips ranged from 4° of retroversion to 32° of anteversion with a mean of 15.0 ± 9.6° (CI 11.1°, 18.9°) (p=0.427) (Fig. 4). The anteversion of 40 (56%) of the primary acetabular components were within the target zone of 10 to 30°, while 19 (27%) were below the target zone and thus was surgically overestimated, and 12 (17%) were above the target range and thus was surgically underestimated. The anteversion of 19 (73%) of the revision acetabular components were within the target zone, while 6 (23%) were below the target zone and thus were surgically overestimated, and 1 (4%) were above the target range and thus was surgically underestimated. The differences in distribution between the primary and revision operations were not significant (p=0.183) (59% versus 63% within the target zone).

Fig. (4)

Distribution of acetabular component version in patients operated with primary or revision total hip arthroplasty.



There were no significant differences in acetabular component version between the cases operated by posterior (16.8 ± 12.7°, CI 13.1°, 20.6°) versus direct lateral approach (17.3 ± 12.9°, CI 14.4°, 20.2°), and the cups were positioned in 59% versus 63% within the target zone. During a 4-5 years follow up there have been no dislocations or other complications.

DISCUSSION

Improper acetabular component orientation negatively affects the outcome of total hip arthroplasty. With conventional techniques, numerous variables may contribute to variability in cup positioning during surgery. We found that using a cementless porous coated and hemispherical cup, there was a wide range of component version, but this was not significantly different in revision as compared to primary THA. Our null hypothesis that there are no differences in acetabular component version between primary and revision THA with the use of a cup positioner with an alignment frame was confirmed. The clinical impact is that a cup positioner with an alignment frame in revision of the acetabular component may be as reliable as in primary THA.

Strength of our study is that we used the same type of acetabular prosthesis in all cases. It has been shown that different types of prostheses may influence the results [13Bosker BH, Verheyen CC, Horstmann WG, Tulp NJ. Poor accuracy of freehand positioning during total hip arthroplasty. Arch Orthop Trauma Surg 2007; 127: 375-9.]. A weakness of the study is that 5 different surgeons might operate the cup positioner differently. However, this might also be considered strength of the study, as it is regular in orthopedic practice that there are different surgeons doing THA at the hospitals. It has been shown that senior surgeons do better than residents [13Bosker BH, Verheyen CC, Horstmann WG, Tulp NJ. Poor accuracy of freehand positioning during total hip arthroplasty. Arch Orthop Trauma Surg 2007; 127: 375-9.]. In our study the surgeons were all experience, and no one differed systematically form the others in doing cup positioning. Another weakness of the study is that we used two different surgical approaches, but as there were no differences between them in cup positioning, we consider this as a minor weakness.

The use of CT to measure cup version is considered more accurate than plain radiography with a standard deviation of interobserver error of about 3° [14Olivencrona H, Weidenhielm L, Olivencrona L, et al. A new method for measuring cup orientation after total hip arthroplatsy: a study of 10 patients. Acta Orthop Scand 2004; 75: 252-60.-16Ghelman B, Kepler CK, Lyman S. CT outperforms radiography for determination of cup version after THA. Clin Orthop Rel Res 2009; 467: 2362-70.]. But even CT studies of the cup position should be interpreted with caution because there are variations of the pelvic orientation depending on patient positioning, and different conventions are used to describe the cup orientation [17Eddine TA, Migaud H, Chantelot C, et al. Variations of pelvic anteversion in lying and standing positions: analysis of 24 control subjects and implications for CT measurements of position of a prosthetic cup. Surg Radiol Anat 2001; 23: 105-.-19Blondel B, Parratte S, Tropiano P, et al. Pelvic tilt measurement before and aftertotal hip arthroplasty. Orthop Traumatol Surg Res 2009; 95: 568-72.]. The patients were CT examined in the supine position while they were operated in the lateral decubitus position. In the lateral decubitus position correct positioning of the patient may be more difficult than in the supine position because the true anatomic conditions can just be approximated [20Wohlrab D, Radetzki F, Noser H, Mendel T. Cup positioning in total hip arthoplasty: spatial alignment of the acetabular entry plane. Arch Orthop Trauma Surg 2012; 132: 1-7., 21Beckmann J, Lüring C, Tingart M, et al. Cup positioning in THA: current status and pitfalls.A systematic evaluation of the literature. Arch Orthop Trauma Surg 2009; 129: 863-72.].

We used an uncemented cup, and in all our revision cases we had more than 50% contacts between the cup and the host bone as evaluated by the surgeon. In reconstructions of the failed acetabular component, a porous-coated cup secured to host bone with multiple screws is a method of choice [22Issack PS, Nousiainen M, Beksac B, et al. Helfet DL. Sculc TP.Buly RL. Acetabular component revision in total hip arthroplasty. Part I cementless shells. Am J Orthop 2009; 38: 509-6.]. For the intraoperative assessment of cup orientation, anatomic landmarks is mandatory, but loss of bone stock in our revision cases did not influence cup positioning as compared to primary THA with the use of the acetabular cup positioner. In all revision cases we used screws than may slightly have modified the position of the implant shell. However, this could hardly have been of any significance as there were no differences between the primary cases were no screws were used and the revision cases.

In a retrospective CT-controlled study, Saxler et al. [8Saxler G, Marx A, Vandevelde D, Langlotz U, et al. Accuracy of free-hand cup positioning: a CT based measurement of cup placement in 105 totalhip arthroplasties. Int Orthop 2004; 28: 198-201.] showed that only 27 out of 105 cups (26%) in primary THA were placed within the safe zone of Lewinnek [6Lewinnek GE, Lewis JL, Tarr R, et al. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 1978; 60: 217-0.]. In a second study DiGioa et al. [7DiGioia AM, Jaramaz B, Plakseychuk AY, et al. Comparison of a mechanical acetabular alignment guide with computer placement of the socket. J Arthroplasty 2002; 17: 359-64.] used a specific mechanical acetabular alignment guide, and the results were controlled preoperatively with a hip navigation system. In 74 hips only 22% of the cups were placed within the Lewinnek’s safe zone. In these studies there was a tendency to underestimate the anteversion of the acetabular component. We therefore aimed to position the cup 5° more anteverted than the safe zone of Lewinnek, and our data demonstrate better accuracy of cup positioning. We overestimated the acetabular component version more frequently than it was underestimated in relation to our intraoperative aim. However, it has been shown that CT measurements of the acetabular anteversion in the supine position are about 10 degrees lower than in the standing position as evaluated by biplanar imaging [23Polkowski GG, Nunley RM, Ruh EL, et al. Does Standing Affect Acetabular Component Inclination and Version After THA?. Clin Orthop Rel Res 2012; 470: 2988-94.]. On the other hand, as compared to the safe zone of Lewinnek more cups were positioned above this zone than below. Coventry et al. [24Coventry MB, Beckenbaugh RD, Nolan DR, Ilstrup DM. Total hip arthroplasties: study of postoperative course and early complications. J Bone Joint Surg Br 1974; 56: 273-84.] found a significant association between acetabular retroversion and posterior dislocation. On the other hand, Lewinnek et al. [6Lewinnek GE, Lewis JL, Tarr R, et al. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 1978; 60: 217-0.] reported a higher incidence of anterior dislocations in THA with more than 25° of acetabular component anteversion. Then, both excess anteversion and retroversion need to be avoided to prevent dislocation. However, the risk factors that predispose to dislocation are multivariate and include patient-related, operative and implant design variables [25Sanchez-Sotelo J, Berry DJ. Epidemiology of instability after total hip replacement. Orthop Clin North Am 2001; 32: 54352.]. We used a rather small head, but malpositioning and the use of a small head in our series may have been compensated for by the elevation of the polyethylene insert. During a follow-up period of 4-5 years we have had no dislocations.

At present, computer navigation system seems to be a most reliable tool for cup positioning [8Saxler G, Marx A, Vandevelde D, Langlotz U, et al. Accuracy of free-hand cup positioning: a CT based measurement of cup placement in 105 totalhip arthroplasties. Int Orthop 2004; 28: 198-201., 10Kalteis T, Handel M, Bäthis H, Perlick L, Tingart M, Grifka J. Imageless navigation for insertion of the acetabular component in total hip arthroplasty.Is it as accurate as CT-based navigation. J Bone Joint Surg Br 2006; 88: 163-7., 26Honl M, Schwieger K, Salineros M, et al. Orientation of the acetabular component.A comparison of five navigation systems with conventional surgical technique. J Bone Joint Surg Br 2006; 88: 1401-5., 27Parratte S, Argenson JN. Validation and usefulness of a computer-assisted cup positioning system in total hip arthroplasty.A prospecive.randomized., controlled study. J Bone Joint Surg Am 2007; 89: 494-9.]. However, the use of this system is not widely adopted due to its high costs, complexity and operating time, and individual studies are too small to allow conclusive statements on the potential benefit. Alignment guides have been developed to improve free hand techniques in cup positioning, but still we found variable accuracy of cup positioning both in primary and revision THA. The reason that the variability was equal in primary and revision cases may be that the alignment rod is positioned according to the body axis and loss of bone stock in revision cases thereby is of less significance. The clinical application of our study is that we would recommend an increased target zone from 10° to 30° rather than the safe zone defined by Lewinnek.

Apart from cup orientation, outcomes of THA such as longevity, range of motion, impingement and dislocation further depend on the head-neck ratio, the offset and the stem orientation [28Malik A, Maheshwari A, Dorr LD. Impingement with total hip replacement. J Bone Joint Surg Am 2007; 89: 1832-42., 29Widmer KH. Containment versus impingement: finding a compromise for cup placement in total hip arthroplasty. Int Orthop 2007; 31: S29-33.]. In addition, surgical approach and endogenous factors such as comorbidity and muscular status may contribute to the fate of the hip joint [30Soong M, Rubash HE, Macaulay W. Dislocation after total hip arthroplasty. J Am Acad Orthop Surg 2004; 12: 31421., 31Meek RM, Allan DB, Mc P, et al. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res 2006; 447: 9-18.]. In our study we found variable accuracy of acetabular cup positioning, but with the use of an acetabular positioner that relies on the body axis there are equal results in revision as in primary THA.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

ACKNOWLEDGEMENTS

Declared none.

REFERENCES

[1] Kennedy JG, Rogers WB, Soffe KE, et al. Effect of acetabular component orientation on recurrent dislocation. pelvic osteoysis polyethylene wear, and component migration. J Arthroplasty 1998; 13: 530-4.
[2] Jolles BM, Zangger P, Leyvraz PF. Factors predisposing to dislocation after primar total hip prosthesis: a multivariate analysis. J Arthroplasty 2002; 17: 282-8.
[3] Barrack RL. Dislocation after total hip arthroplasty: implant design and orientation. J Am Acad Orthop Surg 2003; 11: 89-99.
[4] Wan Z, Boutary M, Dorr LD. The influence of acetabular component position on wear in total hip arthroplasty. J Arthroplasty 2008; 23: 51-6.
[5] Asayama I, Akiyoshi Y, Naito M, Ezoe M. Intraoperative pelvic motion in total hip arthroplasty. J Arthroplasty 2004; 19: 992-7.
[6] Lewinnek GE, Lewis JL, Tarr R, et al. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 1978; 60: 217-0.
[7] DiGioia AM, Jaramaz B, Plakseychuk AY, et al. Comparison of a mechanical acetabular alignment guide with computer placement of the socket. J Arthroplasty 2002; 17: 359-64.
[8] Saxler G, Marx A, Vandevelde D, Langlotz U, et al. Accuracy of free-hand cup positioning: a CT based measurement of cup placement in 105 totalhip arthroplasties. Int Orthop 2004; 28: 198-201.
[9] Minoda Y, Kadowaki T, Kim M. Acetabular component orientation in 834 total hip arthroplasties using a manual technique. Clin Orthop Relat Res 2006; 445: 186-91.
[10] Kalteis T, Handel M, Bäthis H, Perlick L, Tingart M, Grifka J. Imageless navigation for insertion of the acetabular component in total hip arthroplasty.Is it as accurate as CT-based navigation. J Bone Joint Surg Br 2006; 88: 163-7.
[11] Haaker RGA, Tiedjen K, Otersbach A, et al. Comparison of conventional versus computer-navigated acetabular component insertion. J Arthroplasty 2007; 22: 151-9.
[12] Najarian BC, Kilgore JE, Markel DC. Evaluation of component positioning in primary total hip arthroplasty using an imageless navigation device compared to traditional methods. J Arthroplasty 2009; 24: 15-21.
[13] Bosker BH, Verheyen CC, Horstmann WG, Tulp NJ. Poor accuracy of freehand positioning during total hip arthroplasty. Arch Orthop Trauma Surg 2007; 127: 375-9.
[14] Olivencrona H, Weidenhielm L, Olivencrona L, et al. A new method for measuring cup orientation after total hip arthroplatsy: a study of 10 patients. Acta Orthop Scand 2004; 75: 252-60.
[15] Tannast M, Langlotz U, Siebenrock KA, et al. Anatomic referencing of cup orientation intotal hip arthroplasty. Clin Orthop Rel Res 2005; 436: 144-50.
[16] Ghelman B, Kepler CK, Lyman S. CT outperforms radiography for determination of cup version after THA. Clin Orthop Rel Res 2009; 467: 2362-70.
[17] Eddine TA, Migaud H, Chantelot C, et al. Variations of pelvic anteversion in lying and standing positions: analysis of 24 control subjects and implications for CT measurements of position of a prosthetic cup. Surg Radiol Anat 2001; 23: 105-.
[18] Nishihara S, Sugano N, Nishii T, et al. Measurements of pelvic flexion angle using three-dimensional computed tomography. Clin Orthop Relat Res 2003; 411: 140-51.
[19] Blondel B, Parratte S, Tropiano P, et al. Pelvic tilt measurement before and aftertotal hip arthroplasty. Orthop Traumatol Surg Res 2009; 95: 568-72.
[20] Wohlrab D, Radetzki F, Noser H, Mendel T. Cup positioning in total hip arthoplasty: spatial alignment of the acetabular entry plane. Arch Orthop Trauma Surg 2012; 132: 1-7.
[21] Beckmann J, Lüring C, Tingart M, et al. Cup positioning in THA: current status and pitfalls.A systematic evaluation of the literature. Arch Orthop Trauma Surg 2009; 129: 863-72.
[22] Issack PS, Nousiainen M, Beksac B, et al. Helfet DL. Sculc TP.Buly RL. Acetabular component revision in total hip arthroplasty. Part I cementless shells. Am J Orthop 2009; 38: 509-6.
[23] Polkowski GG, Nunley RM, Ruh EL, et al. Does Standing Affect Acetabular Component Inclination and Version After THA?. Clin Orthop Rel Res 2012; 470: 2988-94.
[24] Coventry MB, Beckenbaugh RD, Nolan DR, Ilstrup DM. Total hip arthroplasties: study of postoperative course and early complications. J Bone Joint Surg Br 1974; 56: 273-84.
[25] Sanchez-Sotelo J, Berry DJ. Epidemiology of instability after total hip replacement. Orthop Clin North Am 2001; 32: 54352.
[26] Honl M, Schwieger K, Salineros M, et al. Orientation of the acetabular component.A comparison of five navigation systems with conventional surgical technique. J Bone Joint Surg Br 2006; 88: 1401-5.
[27] Parratte S, Argenson JN. Validation and usefulness of a computer-assisted cup positioning system in total hip arthroplasty.A prospecive.randomized., controlled study. J Bone Joint Surg Am 2007; 89: 494-9.
[28] Malik A, Maheshwari A, Dorr LD. Impingement with total hip replacement. J Bone Joint Surg Am 2007; 89: 1832-42.
[29] Widmer KH. Containment versus impingement: finding a compromise for cup placement in total hip arthroplasty. Int Orthop 2007; 31: S29-33.
[30] Soong M, Rubash HE, Macaulay W. Dislocation after total hip arthroplasty. J Am Acad Orthop Surg 2004; 12: 31421.
[31] Meek RM, Allan DB, Mc P, et al. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res 2006; 447: 9-18.

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


Browse Contents




Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open