- Email: [email protected]
Journal scan
Journal Scan
95
true picture of their efficacy. Robotic and laparoscopic surgery has come to stay and will probably replace open surgery in the next few years.
It look an average of 12 minutes longer to insert the acetabular cup by computer-assisted technique as compared to freehand technique. During post-operative radiological assessment of acetabular cup position there were significantly large numbers of outliers in the freehand technique group (57%) as compared to the computer-assisted group (20%). Though the mean abduction and anteversion angles were similar in both the groups, there was significant decrease in percentage of outliers in the computerassisted group.
Contributed by Lt Col D Doddamani Classified Specialist (Surgery & Urology), Army Hospital (R& R), Delhi Cantt-110010.
In this study there was an absence of variation of surgeon’s skills (Single senior surgeon having performed more than 2000 THAs). The differences in number of outliers between the computer assisted group and freehand group are likely to be much more with less experienced/skilled surgeons [2]. This may also explain the lack of difference in mean abduction and anteversion angles. It would be interesting to repeat this study with surgeons of different levels of skills.
Sebastien Parratte, Jean-Noel A. Argenson. Validation and Usefulness of a Computer-Assisted Cup-Positioning System in Total Hip Arthroplasty. A Prospective, Randomised Controlled Study. Journal of Bone & Joint Surgery 2007; 89: 494-9. Mechanical guides and free hand techniques have been used conventionally for optimal orientation of acetabular component during total hip arthroplasty (THA). However, these techniques lead to significant variations between actual and desired implant orientation, as it is difficult to know the exact position of patient on the operating table. Inappropriate position of the acetabular component during THA decreases the hip stability, leads to early wear/loosening and decreases hip motion. In view of these problems, a number of computer assisted navigation systems have been developed as more reliable tools for implant positioning and to improve reproducibility of implant alignment.
When compared with freehand techniques, the use of bone morphing based navigation system in this study helped in decreasing the percentage of outliers in the positioning of the acetabular cup component. However, there are multiple challenges in this new emerging field of computer- assisted surgery. Firstly, there is a concern regarding percutaneous registration of bony landmarks, especially in obese patients (This study contained patients with BMI<27 only). There is a possibility of ultrasound –guided bone morphing being the future in this regard. Secondly, the optimal cup orientation in terms of abduction and anteversion angles has to be individualized for each patients, especially in patients with fixed pelvic tilt. Thirdly, the long-term clinical impact of reducing the number of outliers in cup positioning is yet to be measured. Long term follow up studies will be required to measure the same.
This published study is aimed to clinically validate an imageless computer-assisted navigation system and to compare this new technique with freehand insertion of acetabular component. The imageless system used in the study is based on intra-operative “bone-morning” a concept already being used in knee arthroplasy [1]. Other systems with navigation based on pre-operative CT Scan images are also available but are not a subject of this study.
References 1. Stindel E, Briard JL, Merloz P, Plaweski S, Dubrana F, Lefevre C, Troccaz J. Bone morphing: 3D morphological data for total knee arthroplasty. Computer aided Surg. 2002; 7: 156-68.
A randomized controlled prospective study was performed which included two groups of 30 patients each. All the surgeries were performed by the same surgeon through the same surgical approach in both the groups. In the first group, cup positioning was done with aid of an imageless computer assisted navigation system whereas the cup was placed freehand in the other group. Postoperative, an independent observer measured cup anteversion and abduction angles for all patients on post-operative 3-dimensional CT reconstruction using special cup-evalution software.
2. Jolles BM, Genoud P, Hoffmeyer P. Computer- assisted cup placement echniques in total hip arthroplasty improve accuracy of placement. Clin Orthop Relat Res 2004; 426:174-9. Contributed by Lt Col N Kumar Classified Specialist, Orthopaedics (On Study leave)
Answers to MCQs 1) a
2) c
3) b
4) a
5) b
6) a
7) c
8) d
9) b
10) c
11) b
12) a
13) c
14) a
15) c
MJAFI, Vol. 65, No. 1, 2009
95
true picture of their efficacy. Robotic and laparoscopic surgery has come to stay and will probably replace open surgery in the next few years.
It look an average of 12 minutes longer to insert the acetabular cup by computer-assisted technique as compared to freehand technique. During post-operative radiological assessment of acetabular cup position there were significantly large numbers of outliers in the freehand technique group (57%) as compared to the computer-assisted group (20%). Though the mean abduction and anteversion angles were similar in both the groups, there was significant decrease in percentage of outliers in the computerassisted group.
Contributed by Lt Col D Doddamani Classified Specialist (Surgery & Urology), Army Hospital (R& R), Delhi Cantt-110010.
In this study there was an absence of variation of surgeon’s skills (Single senior surgeon having performed more than 2000 THAs). The differences in number of outliers between the computer assisted group and freehand group are likely to be much more with less experienced/skilled surgeons [2]. This may also explain the lack of difference in mean abduction and anteversion angles. It would be interesting to repeat this study with surgeons of different levels of skills.
Sebastien Parratte, Jean-Noel A. Argenson. Validation and Usefulness of a Computer-Assisted Cup-Positioning System in Total Hip Arthroplasty. A Prospective, Randomised Controlled Study. Journal of Bone & Joint Surgery 2007; 89: 494-9. Mechanical guides and free hand techniques have been used conventionally for optimal orientation of acetabular component during total hip arthroplasty (THA). However, these techniques lead to significant variations between actual and desired implant orientation, as it is difficult to know the exact position of patient on the operating table. Inappropriate position of the acetabular component during THA decreases the hip stability, leads to early wear/loosening and decreases hip motion. In view of these problems, a number of computer assisted navigation systems have been developed as more reliable tools for implant positioning and to improve reproducibility of implant alignment.
When compared with freehand techniques, the use of bone morphing based navigation system in this study helped in decreasing the percentage of outliers in the positioning of the acetabular cup component. However, there are multiple challenges in this new emerging field of computer- assisted surgery. Firstly, there is a concern regarding percutaneous registration of bony landmarks, especially in obese patients (This study contained patients with BMI<27 only). There is a possibility of ultrasound –guided bone morphing being the future in this regard. Secondly, the optimal cup orientation in terms of abduction and anteversion angles has to be individualized for each patients, especially in patients with fixed pelvic tilt. Thirdly, the long-term clinical impact of reducing the number of outliers in cup positioning is yet to be measured. Long term follow up studies will be required to measure the same.
This published study is aimed to clinically validate an imageless computer-assisted navigation system and to compare this new technique with freehand insertion of acetabular component. The imageless system used in the study is based on intra-operative “bone-morning” a concept already being used in knee arthroplasy [1]. Other systems with navigation based on pre-operative CT Scan images are also available but are not a subject of this study.
References 1. Stindel E, Briard JL, Merloz P, Plaweski S, Dubrana F, Lefevre C, Troccaz J. Bone morphing: 3D morphological data for total knee arthroplasty. Computer aided Surg. 2002; 7: 156-68.
A randomized controlled prospective study was performed which included two groups of 30 patients each. All the surgeries were performed by the same surgeon through the same surgical approach in both the groups. In the first group, cup positioning was done with aid of an imageless computer assisted navigation system whereas the cup was placed freehand in the other group. Postoperative, an independent observer measured cup anteversion and abduction angles for all patients on post-operative 3-dimensional CT reconstruction using special cup-evalution software.
2. Jolles BM, Genoud P, Hoffmeyer P. Computer- assisted cup placement echniques in total hip arthroplasty improve accuracy of placement. Clin Orthop Relat Res 2004; 426:174-9. Contributed by Lt Col N Kumar Classified Specialist, Orthopaedics (On Study leave)
Answers to MCQs 1) a
2) c
3) b
4) a
5) b
6) a
7) c
8) d
9) b
10) c
11) b
12) a
13) c
14) a
15) c
MJAFI, Vol. 65, No. 1, 2009