Improvement of arthroscopic surgical performance using a new wide-angle arthroscope in the surgical training
Improvement of arthroscopic surgical performance using a new wide-angle arthroscope in the surgical training
Jae-Man Kwak 0 1
Erica Kholinne 0 1
Maulik Gandhi 1
Arnold Adikrishna 0 1
Hanpyo Hong 0 1
Yucheng Sun 0 1
Kyoung-Hwan Koh 0 1
In-Ho JeonID 0 1
0 Department of Orthopedic Surgery, Asan Medical Center, College of Medicine, Ulsan University , Seoul , South Korea , 2 Department of Orthopedic Surgery, St. Carolus Hospital , Jakarta , Indonesia , 3 Upper Limb Department, Robert Jones & Agnes Hunt Hospital , Oswestry, England , United Kingdom
1 Editor: Gabriel Costa Serra?o de Arau ?jo, Universidade Federal Fluminense , BRAZIL
We have developed a new arthroscope with a field of view of 150?. This arthroscope requires less motion to maneuver and exhibits reduced optical error. It also improves how novices learn arthroscopy. We hypothesized that the surgical performance with this arthroscope is superior to that with a conventional arthroscope. This study tested the hypothesis by using motion analysis and a new validated parameter, ?dimensionless squared jerk? (DSJ).
Data Availability Statement: All relevant data are
within the paper and its Supporting Information
Funding: This research was supported by a grant
of the Korea Health Technology R&D Project
through the Korea Health Industry Development
Institute, funded by the Ministry of Health &
Welfare, Republic of Korea (grant number:
HI13C1634). The funding source had no
involvement in the study design; collection,
analysis, and interpretation of data; writing of the
We compared the surgical performance between the use of the wide-angle arthroscope and
that of the conventional arthroscope among 14 novice orthopedic residents who performed 3
standardized tasks 3 times with each arthroscope. The tasks simulated the surgical skills in
arthroscopic rotator cuff repair. The arthroscope motion was analyzed using an optical
tracking system. The differences in performance parameters, such as the time taken to complete
the tasks, average acceleration of the hands (m/s2), number of movements, and total path
length (m) including DSJ between the 2 arthroscopes were investigated using paired t-tests.
All estimated values for the tasks using the 150? arthroscope were lower than those for the
tasks using the 105? arthroscope. Statistically significant differences in performance
between the 2 arthroscopes were observed only for DSJ (p = 0.014) and average
acceleration (p = 0.039).
DSJ and average acceleration are reliable parameters for representing hand-eye
coordination. The surgical performance of novice arthroscopists was better with the new wide-angle
arthroscope than with the conventional arthroscope.
report; and decision to submit the article for
Shoulder arthroscopy has evolved and has become an important method in minimally invasive
surgery. As arthroscopic techniques have evolved, arthroscopy has become the gold standard
method for the diagnosis and management of shoulder disorders [1?4]. However, several
issues remain, particularly with respect to the long learning curve and the time required for
training. Additionally, technical errors arise from the limitations of hand-eye coordination
required for the use of arthroscopic systems, especially for novice arthroscopists. Several
studies have shown that training using a dry or virtual simulator is effective and safe for
overcoming these issues [5?7]. However, cost-effectiveness remains an issue in every training hospital.
On the basis of our experience, one of the main problems in arthroscopy is the limited field
of view (FOV) of conventional arthroscopic systems. Several studies have reported that a
limited arthroscopic FOV can make it difficult to identify entire anatomic structures, and this was
often associated with poor hand-eye coordination during surgical triangulation and handling
of the instrument [
]. We hypothesized that a wide-angle arthroscope with a higher FOV
would result in better hand-eye coordination and would bring important benefits such as
acceleration of learning, reduction of technical errors, and improvement in the long-term
performance of surgical skills.
The aim of this study was to compare hand-eye coordination and the performance of
surgical skills between the use of a newly developed wide-angle arthroscope (150? FOV) and that of
the conventional arthroscope (105? FOV). We used motion analysis to evaluate the
performance of novice arthroscopists. We assessed their hand-eye coordination by using the
?dimensionless squared jerk? (DSJ)[
], which is widely accepted as an objective parameter of
handeye coordination in the field of engineering.
Materials and methods
All procedures performed in studies involving human participants were in accordance with
the ethical standards of the institutional and/or national research committee and with the 1964
Helsinki Declaration and its later amendments or comparable ethical standards. Institutional
Review Board Approval was obtained from Asan Medical Center prior to study (no. 2017?
0292). Written Informed consent was obtained from all individual participants included in the
A total of 14 right-handed orthopedic residents with no prior arthroscopic surgical training
were recruited by announcement for open recruitment in Asan Medical Center during May
A conventional arthroscopic system (IM4000, IM4120; ConMed Linvatec, Utica, NY, USA)
was used to perform the tasks in this study, and compared with a new wide-angle arthroscopic
system (MGB Endoscopy Company, Seoul, Korea) that has a high-definition lens with a 150?
FOV (Fig 1).
The participants performed a set of tasks using the 2 arthroscopes sequentially in random
order. A Latin square counterbalancing technique was used to compensate for learning effects
from previous practice [
]. Before the experiment, each participant was given an instructional
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Fig 1. The 2 arthroscopes used in this study, with representative images showing the field of view. (a) The conventional arthroscopic
system. (b) The new wide-angle arthroscopic system.
video manual that covers all the experimental processes and arthroscopic tasks to be
performed, as well as provides an introduction to the experimental and surgical instruments. The
participants were allowed 10 min to familiarize themselves with the experimental system and
surgical instruments. The participants performed the tasks without any assistance.
A dry right shoulder model (Arthrex, Naples, FL, USA) was used for the tasks (Fig 2A).
Black nylon sutures were made at 5 sites along the lateral border of the rotator cuff, and the
bicipital groove was marked in blue. A pilot hole for an anchor was made at an appropriate
position on the greater tuberosity (Fig 2B). The model and related instruments were set up on
a table, with a pair of reflective hand illustrations placed on the table to mark the start and end
positions for the participants (Fig 2B).
The 3 assigned tasks, which simulated basic surgical techniques, were as follows: (a)
touching the 5 points along the rotator cuff marked by sutures twice using a grasper, passing through
the anterior portal; (b) inserting an anchor at the predetermined point on the footprint of the
rotator cuff; and (c) pulling the suture through the anterior portal using the grasper (Fig 3A?
3C). These 3 tasks have been validated by previous studies [
]. Each task was performed
3 times with each scope.
Hand motion analysis
During the tasks, the participants? hand movements were tracked using an optical motion
analysis system comprising 8 motion-capture cameras (Prime 41; Natural Point Inc., Corvallis,
OR, USA) (Fig 4A), 10-mm reflective marker balls placed on the third metacarpal area of the
dorsal side of the participants? hands, and tracking software (Motive: Tracker, Natural Point
Inc.) (Fig 4B). The system continuously recorded 3-dimensional data for the 2 reflective
markers on each participant?s hands. The following data were collected and analyzed using motion
analysis, as described in previous reports [
10, 15, 17
]: (a) the time taken (in seconds) to
complete the tasks, recorded from the time the participant started to lift the hand from the table
until the time the task was completed and the participant?s hand was resting on the table; (b)
the average acceleration of the hands (m/s2); (c) the number of movements made, defined by
changes in velocity with respect to the time that exceeded the predetermined threshold value
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Fig 2. (a) A dry human shoulder model was used for the arthroscopic tasks. (b) Black nylon sutures were made at 5 sites along the lateral border of the
rotator cuff (red arrows), and the bicipital groove was marked in blue. A pilot hole for an anchor was made at an appropriate position on the greater
of 10 m/s2; and (d) the total path length (m), which was calculated as the total distance traveled
by the reflective marker during the task.
By using the collected data, DSJ, a physical index for estimating hand-eye coordination, was
calculated in MATLAB 2012b (MathWorks, Torrance, CA, USA) with the following formula:
DSJ ? ? tt12 x??t?2dt? D3=v2mean;
where D is the duration of the movement and vmean is the average velocity of the movement.
The time taken to complete the tasks, total path length and number of movements were
normally distributed and categorized as continuous variables. DSJ and average acceleration were
not normally distributed. An a priori power analysis showed that a sample size of 34 attempts
of using each arthroscope would have sufficient power to show a significant difference,
assuming a significance level of 0.05 and power of 80%. The p-values for the time to complete the
tasks, total path length, and number of movements were calculated using a paired t-test, with
the Wilcoxon signed rank test used for DSJ and average acceleration. A value of p < 0.05 was
considered to indicate statistical significance. The analyses were performed using the SPSS
software package (version 20.0; IBM Corp., Armonk, NY, USA).
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Fig 3. The 3 arthroscopic tasks. (a) Touching 5 points on the rotator cuff twice using a grasper, passing through the anterior portal. (b) Anchor insertion at a
predetermined point on the footprint of the rotator cuff. (c) Pulling the suture through the anterior portal by using the grasper.
DSJ (p = 0.014) and average acceleration (p = 0.039) were the only parameters that showed a
statistically significant difference between the 2 arthroscopes. There were no other statistically
significant differences between the arthroscopes, including the time taken to complete the
tasks (p = 0.282), number of movements (p = 0.323), or total path length (p = 0.142). All other
estimated values for the tasks using the 150? arthroscope were lower than those for the tasks
using the 105? arthroscope. The collected data are summarized in Table 1.
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Fig 4. The optical motion analysis system, comprising 8 motion-capture cameras, reflective markers placed on the third metacarpal area of the dorsal
side of the participant?s hand to track hand motion, and tracking software.
Previous studies have demonstrated that improving the arthroscopist?s view results in better
performance; in other words, improved hand-eye coordination leads to better surgical
]. On the basis of this theory, we introduced the prototype of the
wideangle arthroscope in a previous study . Compared with conventional arthroscopes, which
have a 105? FOV, the new arthroscope with a 150? FOV provides unprecedented wide-angle
viewing. However, our previous study scientifically demonstrated that the wide-angle view
would not simply result in superior performance because various complicated movements are
involved; the main issue is identifying a specific tool to estimate movement quality. The widely
used global rating scale is an efficient and easy way to estimate surgical performance [
However, assessment of subjective factors remains to be done because arthroscopy is
conducted under the observation of another person .
To overcome this subjective limitation, we tried to objectively find a tool for assessing
hand-eye coordination, which is highly related to surgical performance. Fortunately, motion
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tracking systems make it possible to obtain objective data with respect to hand movements
]. By using a motion tracking system, we evaluated the participants? performance
and hand movements according to the time taken to complete the tasks, total path length
traveled by the hands, number of movements made, and average acceleration of the hands. From
these data, we calculated DSJ, a relatively simple indication of movement quality. A ?jerk? is a
physical value indicating the rate of change of acceleration for a movement. In DSJ, this is
squared to counterbalance any negative values and is presented as a dimensionless parameter
to allow it to be comparable. DSJ has previously been used to evaluate several movement
] and has been considered an effective parameter for quantifying the quality of
movement [33, 34]. Hogan and Sternad [
] noted that ?a dimensionless jerk-based measure
properly quantifies common deviations from smooth, coordinated movement.? This suggests
that appropriate measurement of DSJ would reflect the quality of the hand movements of
The results of our previous study, which demonstrated the validity of DSJ for the objective
assessment of hand-eye coordination, indicated that DSJ can be used to objectively assess
surgical performance [
]. In the present study, DSJ and average acceleration showed statistically
significant differences between the results for the 2 arthroscopes. On the basis of the results,
we finally objectively demonstrated the superiority of the new wide-angle arthroscope
compared with the conventional arthroscope. we believe that the new wide-angle arthroscope may
improve arthroscopic performance and can serve as a superior training tool compared with
the conventional arthroscope.
One limitation of this study was the relatively small sample size. Second, measuring the
"working" hand using the instrument, the formula will be influenced by the expected increase
in motion of the "scope" hand when the scope with the more limited field of view is used. This
could be the compounding factor. In addition, the arthroscopic surgical tasks were performed
using a dry model, which does not perfectly reflect the clinical situation. To prove the
improvement of surgical performance in clinical situation, the 2nd prototype of wide-angle arthroscope
is under development and has been used to determine the applicability in cadaveric study.
Although some obstacles to apply to surgery have been reported including the torsional image,
we believe that the wide-angle arthroscope would give the more benefit than conventional
arthroscope in a surgical field. Technical errors and long-term benefits will be also assessed in
our future study.
The surgical performance of novice arthroscopists was improved with the use of the
wideangle arthroscope as compared with the use of the conventional arthroscope.
S1 File. IRB file (IRB for DSJ.pdf).
S2 File. Data file (data_PONE-D-18-21170.xlsx).
This study was presented at the 2017 Asia Arthroscopy Congress Meeting.
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Conceptualization: Maulik Gandhi, Arnold Adikrishna, Hanpyo Hong, In-Ho Jeon.
Data curation: Jae-Man Kwak, Erica Kholinne, Maulik Gandhi, Arnold Adikrishna, Hanpyo
Hong, Yucheng Sun, In-Ho Jeon.
Formal analysis: Jae-Man Kwak, Maulik Gandhi, Arnold Adikrishna, Hanpyo Hong.
Funding acquisition: In-Ho Jeon.
Investigation: In-Ho Jeon.
Methodology: Erica Kholinne, Yucheng Sun, In-Ho Jeon.
Project administration: In-Ho Jeon.
Supervision: In-Ho Jeon.
Validation: Jae-Man Kwak, Erica Kholinne, Kyoung-Hwan Koh, In-Ho Jeon.
Visualization: Jae-Man Kwak, Erica Kholinne.
Writing ? original draft: Jae-Man Kwak.
Writing ? review & editing: Jae-Man Kwak, Kyoung-Hwan Koh, In-Ho Jeon.
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