Computer-assisted Navigation System Research Articles

Minimally invasive intelligent innovative technologies in foot and ankle surgery: development status and prospects

The rapid development of technology has ushered in a new era of minimally invasive and intelligent surgery.Minimally invasive surgeries, such as small incision, percutaneous surgery, arthroscopic surgery, and endoscopic surgery, have contributed to less invasive surgical trauma, better cosmesis, and faster recovery. Furthermore, the recent adoption of artificial intelligence (AI) has introduced new assistances and tools for minimally invasive foot and ankle surgery. By the help of advanced AI algorithms, surgeons can accurately make diagnose and personalized treatment strategies. The application of computer-assisted navigation systems and robotics has facilitated precise surgical procedures and real-time confirmation of surgical outcomes. Foot and ankle surgery has lagged behind other surgical specialties in adopting these advancements. Currently, the integration of various forms of minimally invasive surgery and AI technology stands as the main trend in the development of foot and ankle surgery. It is believed that in the near future, intelligent minimally invasive surgery will become the mainstream in the domain of foot and ankle.

Optimizing Acetabular Positioning: A Comprehensive Review of Contemporary Strategies in Total Hip Arthroplasty.

Total hip arthroplasty (THA) is a widely practiced surgical intervention to alleviate pain and reinstate functionality in individuals afflicted with hip joint pathology. The positioning of the acetabulum assumes paramount significance in determining the efficacy of THA, exerting profound influences on biomechanical dynamics, stability, and the durability of outcomes over time.This comprehensive review meticulously evaluates contemporary methodologies for optimizing acetabular positioning in THA, encompassing advanced technologies such as computer-assisted navigation systems, patient-specific instrumentation, robotic-assisted surgical approaches, image-based planning techniques, and intraoperative fluoroscopy.Crucially, key discoveries underscore the pivotal role of precise acetabular alignment in mitigating complications such as dislocation, component wear, and impingement. Moreover, the implications for clinical practice accentuate the imperative of continuous education and training to ensure effective deployment of sophisticated methodologies.Recommendations for furthering research and enhancing practice development underscore the necessity of scrutinizing long-term prognoses, assessing cost-effectiveness, and embracing technological innovations perpetually refining THA outcomes. Collaborative endeavors among researchers, practitioners, and industry stakeholders emerge as indispensable drivers of advancement in this domain, fostering an environment conducive to elevating the standard of care for individuals undergoing THA.

Computer-Assisted Navigation in Reverse Shoulder Arthroplasty: Surgical Experience and Clinical Outcomes.

Background: The primary cause of medium- to long-term complications in reverse shoulder arthroplasty (RSA) is the failure of the glenoid component. The purpose of this study was to evaluate both the achievement of planning through computer-assisted navigation and the clinical outcomes at a minimum follow-up (FU) of 12 months. Methods: From December 2019 to December 2022, 57 Equinoxe RSAs with computer-assisted navigation were performed. The average age was 72.8 ± 6.6 years. Using the Orthoblue software, the version and inclination of the glenoid were evaluated from a preoperative CT scan, and planning was performed. Intraoperative navigation data were evaluated, and the clinical outcomes were assessed at a minimum follow-up of 12 months. Results: The average follow-up was 30.7 ± 13.5 months. The planning was reproduced in all implants. No errors in the computer-assisted navigation system were detected. No intraoperative or postoperative complications were recorded. At the final FU, the average active anterior elevation was 143° ± 36°, external rotation was 34° ± 5°, QuickDASH score was 19 ± 16 points, and constant score was 77 ± 18. Conclusions: Computer-assisted navigation is a reliable system for positioning prosthetic implants on challenging glenoids. A longer follow-up period is necessary to confirm the reduction in postoperative complications and the increase in survival compared to traditional RSA.

Robotic-Assisted and Computer-Assisted Navigation Surgery in the Cervical Spine: Current Experiences, Techniques, and Accuracy

Background: In recent years, the role of robotic-assisted and computer-assisted navigation (RA-CAN) systems has significantly expanded in spine surgery, particularly those performed in the thoracic, lumbar and sacral spine showing higher accuracy in pedicle screw placement and improved surgical efficiency. However, there are few reports on these techniques in the cervical spine. The anatomy of the cervical spine possesses additional challenges such as the close proximity to critical neurovascular structures. Purpose: In this article, we present the existing clinical experience of RA-CAN in the cervical spine and evaluate technical considerations. Cervical spine screw fixation and decompression using RA-CAN are reviewed. Results: This analysis covers various aspects such as techniques, accuracy, and the types of procedures reported in the literature. Recent reports include surgical procedures such as anterior cervical diskectomy and fusion’s, odontoid fracture fixation, C1 lateral mass, C2 pedicle, translaminar, subaxial spine lateral mass, and mid-cervical spine pedicle screw fixation. There is potential for enormous clinical benefit to navigated decompression in cervical CAN procedures also. Future opportunities include further improvements in imaging co-localization, pre-surgical planning software, and mechanization of surgical procedures for instrumentation and decompression. Conclusion: The growth of RA-CAN in spinal surgery has shown significant potential in its application in the cervical spine for fusion procedures as well as decompression. By understanding the potential limitations and techniques reported from early experiences, previous techniques can be improved and provide further benefits for accuracy and less invasive surgery.

Computer-Assisted Intramedullary Nailing of Intertrochanteric Fractures Did Not Prevent Tip–Apex Distance Outliers

Intertrochanteric femoral fractures are commonly treated with intramedullary nails (IMNs). A tip–apex distance (TAD) of more than 20–25 mm is associated with an increased risk of cut-out. The Stryker Adaptive Positioning System (ADAPT) is a computer-assisted navigation system designed to reduce TADs. We aim to assess if the ADAPT reduces the number of outliers with a TAD > 20 mm. All patients with intertrochanteric fractures treated with an IMN between 1 September 2020 and 12 March 2022 were included. Patients were included in three periods: a pre-ADAPT period (55 patients); an ADAPT period (50 patients), where it was compulsory to use the system; and a post-ADAPT period after the discontinuation of the system (59 patients). The TADs and lag screw protrusions beyond the lateral cortex were measured. The median TADs in the three periods were 17.0 mm (8–31 mm), 15.5 mm (9–30 mm), and 18.0 mm (11–32 mm), respectively. The absolute number of outliers with a TAD > 20 mm decreased from 15/55 patients in the pre-ADAPT period to 11/50 patients during the ADAPT period. This observation was not statistically significant, but this is likely due to the lack of power of the present study to show changes of this magnitude. However, our expectation that the ADAPT would diminish outliers markedly or close to zero outliers was not met, as we observed 11/50 = 22% outliers with a TAD > 20 mm when using computer-assisted surgery, i.e., ADAPT and Gamma3 for intertrochanteric fractures. Based on these findings, the use of the ADAPT was discontinued at our level 1 trauma center.

Poor usability of computer-assisted navigation for hip fracture surgery

IntroductionThe STRYKER ADAPT computer-assisted navigation system provides intraoperative feedback to the surgeon regarding implant placement of the Gamma3 nail. The usability of the ADAPT system has not been evaluated. The aim of the study was to investigate the perceived usability of the ADAPT system.Materials and methodsThis was a descriptive study with prospectively collected data. ADAPT was introduced at Aarhus University Hospital in February 2021. Prior to introduction, surgeons at the department attended a general introduction to the system. ADAPT was introduced to the surgical nurses and was on display at the surgical ward at more than one occasion, where personal introduction to the system was possible. After introduction, it was mandatory to use ADAPT when using the Gamma3 nail to treat intertrochanteric femur fractures. After each procedure, primary and an eventual supervisor answered a questionnaire, which encompassed the System Usability Scale (SUS) questionnaire. The SUS is a ten-item questionnaire regarding the perceived usability of a system. SUS scores were translated to adjectives, describing user experience on a 7-point adjective scale (worst imaginable, awful, poor, ok, good, excellent, best imaginable). User acceptability, defined as “not acceptable”, “marginal” or “acceptable”, was also used to interpret the SUS scores.ResultsADAPT was used in 50 procedures by 29 different surgeons, with varying skill-level. Median SUS-score after first-time use of ADAPT for all 29 surgeons was 43 (range: 5–60), which translated to “poor” or “not acceptable”. For surgeons who performed ≥ 3 ADAPT-assisted procedures, there were no statistically significant difference in their first to latest SUS-score (median difference: 4.3, p = 0.5). In free text comments ADAPT was positively described as helpful in placement of K-wire and providing educational opportunities for inexperienced surgeons and negatively as inconsistent, slow, time consuming, and causing excessive fluoroscopy.ConclusionsUsability and acceptability of ADAPT was rated as “poor” or “not acceptable” by the majority of operating surgeons. ADAPT has not been used at our institution based on these findings. The System Usability Scale may be used in further research exploring usability and acceptability of novel computer-assisted navigation systems for orthopaedic surgery.

Intraoperative navigation system use increases accuracy of glenoid component inclination but not functional outcomes in reverse total shoulder arthroplasty: a prospective comparative study.

While the use of computer-assisted navigation systems in prosthetic implantation is steadily increasing, its utility in reverse shoulder arthroplasty (RSA) remains unclear. The purpose of this study was to evaluate the clinical utility of an intraoperative navigation system in patients undergoing RSA. Patients undergoing navigated or standard RSA at a single institution between September 2020 and December 2021 were prospectively enrolled. Exclusion criteria included noncompliance with study procedures or humeral fracture. Outcome measures included postoperative version and inclination, range of motion (ROM), complications, and patient-reported outcome measurements (PROMs: American Shoulder and Elbow Surgeons score [ASES], Disabilities of the Arm, Shoulder, and Hand score [DASH], Simple Shoulder Test [SST], and Visual Analog Scale [VAS]) at final follow-up. The final cohort contained 16 patients with navigation and 17 with standard RSA at a mean follow-up of 16months (range 12-18months). Average age was 72years (range 66-80years), 8 male (24%) and 25 female (76%). There were no differences in demographics between groups (p > 0.05). At baseline, the navigated group had a greater proportion of Walch B1 and B2 glenoids (p = 0.04). There were no differences between groups regarding baseplate type and native/planned/postoperative glenoid version and inclination. In both groups, planned and postoperative versions were not significantly different (p = 0.76). Patients who did not have navigation demonstrated significant differences between planned and postoperative inclination (p = 0.04), while those with navigation did not (p = 0.09). PROM scores did not differ between groups at final follow-up for SST (p = 0.64), DASH (p = 0.38), ASES (p = 0.77), or VAS (p = 0.1). No difference in final ROM was found between groups (p > 0.05). Over 50% of all screws in both groups were positioned outside the second cortex (p = 0.37), albeit with no complications. There were no statistically significant differences in ROM, PROMs, and satisfaction between patients receiving computer-navigated and standard RSA at a short-term follow-up. Despite more severe preoperative glenoid erosion in the navigated group, all patients were able to achieve an appropriate neutral axis postoperatively. The cost effectiveness and appropriate use of computer-navigated RSA warrant specific investigation in future studies. II, prospective cohort study. 9/1/2020 to 12/31/2021.

A Cadaveric Feasibility Study of an Automatic Multi-Degrees of Freedom Surgical Robot for Percutaneous Scaphoid Guide Pin Insertion.

Background: Percutaneous fixation of scaphoid fractures need accurate guide pin insertion. The emergence of computer-assisted navigation and robotic surgery may provide a promising solution to this problem. Methods: This study presents the development of an automatic multi-degrees of freedom (DOF) surgical robot with computer-assisted navigation system, focusing on percutaneous scaphoid guide pin insertion. Using this device, along with a 3D fluoroscopy unit, we have conducted an experimental study on 10 cadavers for percutaneous scaphoid guide pin insertion to verify the feasibility and reliability of the system. Results: The mean operative duration was 29.1 (SD 4.3) minutes. The cadavers required no more than two attempts to achieve desired wire placement, with the mean positioning-error being 2.0 (SD 0.3) mm and the mean angle-deviation 3.6 (SD 0.7)°. Throughout the study, a mean of 2.2 full-cycle fluoroscopy attempts was required for each cadaver during surgery, and no preoperative CT scan was needed. Conclusions: The outcomes show that using the automatic surgical robot to perform the percutaneous scaphoid guide pin insertion is feasible and desired results can be achieved.

Is robotic assistance more eye-catching than computer navigation in joint arthroplasty? A Google trends analysis from the point of public interest.

Computer-assisted navigation system (CAS) and robotic assisted surgery (RAS) have been widely used in joint arthroplasty, but few studies focused on public interest. We aimed to evaluate current trend and seasonality of public interest in CAS and RAS arthroplasty over the past 10years, and forecast the future development. All data related to CAS or RAS arthroplasty from January 2012 to December 2021 were collected through Google Trends. Public interest was described by relative search volume (RSV). Pre-existing trend was evaluated by linear and exponential models. Time series analysis and ARIMA model were utilized to analyze the seasonality and future trend. R software 3.5.0 was for statistics analysis. Public interest in RAS arthroplasty has been continuously increasing (P < 0.001) and exponential model (R2 = 0.83, MAE = 7.35, MAPE = 34%, RSME = 9.58) fitted better than linear one (R2 = 0.78, MAE = 8.44, MAPE = 42%, RSME = 10.67). CAS arthroplasty showed a downtrend (P < 0.01) with equivalent R2 (0.04) and accuracy measures (MAE = 3.92, MAPE = 31%, RSME = 4.95). The greatest popularity of RAS was observed in July and October, while the lowest was in March and December. For CAS, a rise of public interest was in May and October, but lower values were observed in January and November. Based on ARIMA models, the popularity of RAS might continuously increase and nearly double in 2030, along with a stability with slight downtrend for CAS. Public interest in RAS arthroplasty has been continuously increasing and seems to maintain this uptrend in the next 10years, whereas popularity of CAS arthroplasty will likely remain stable.

Current Indications for Spinal Endoscopic Surgery and Potential for Future Expansion.

Endoscopic spine surgery (ESS) has evolved as a safe, effective, and efficient alternative for minimally invasive spine surgery (MISS). The innovation of full-endoscopic systems makes definitive decompression surgery through different approaches feasible. The approach can be determined according to the location of the target lesion or the surgeon's preference. During the past 2 decades, ESS has expanded its indications from lumbar to cervical spines. Except for decompression, endoscopy-assisted fusion surgery is also developing. However, ESS is still evolving and has a steep learning curve. The revolution of technologies and ESS techniques will enable surgeons to treat various spinal diseases more practically. In recent years, the application of the computer-assisted navigation system and augmented reality have reformed imaging quality and interpretation. The endoscopic rhizotomy techniques have opened a new way for MISS of chronic low back pain. This review introduces the current indications of ESS and its potential future expansion.

Image-guided navigation system for minimally invasive total hip arthroplasty (MITHA) using an improved position-sensing marker.

Minimally invasive total hip arthroplasty (MITHA) is a treatment for hip arthritis, and it causes less tissue trauma, blood loss, and recovery time. However, the limited incision makes it difficult for surgeons to perceive the instruments' location and orientation. Computer-assisted navigation systems can help improve the medical outcome of MITHA. Directly applying existing navigation systems for MITHA, however, suffers from problems of bulky fiducial marker, severe feature-loss, multiple instruments tracking confusion, and radiation exposure. To tackle these problems, we propose an image-guided navigation system for MITHA using a novel position-sensing marker. A position-sensing marker is proposed to serve as the fiducial marker with high-density and multi-fold ID tags. It results in less feature span and enables the use of ID for each feature, overcoming the problem of bulky fiducial markers and multiple instruments tracking confusion. And the marker can be recognized even when a large part of locating features is obscured. As for the elimination of intraoperative radiation exposure, we propose a point-based method to achieve patient-image registration based on anatomical landmarks. Quantitative experiments are conducted to evaluate the feasibility of our system. The accuracy of instrument positioning is achieved at 0.33 ± 0.18mm, and that of patient-image registration is achieved at 0.79 ± 0.15mm. And qualitative experiments are also performed, verifying that our system can be used in compact surgical spatial volume and can address severe feature-loss and tracking confusion problems. In addition, our system does not require any intraoperative medical scans. Experimental results indicate that our proposed system can assist surgeons without larger space occupations, radiation exposure, and extra incision, showing its potential application value in MITHA.

Is mid-sulcus line a predictive guide for tibial mechanical axis during total knee arthroplasty?

BackgroundAchieving appropriate alignment of components in total knee arthroplasty (TKA) is essential for optimal functional outcomes as well as implant longevity. Performing TKA in the absence of a computer-assisted navigation system (CANS) mandates the use of accurate anatomical landmarks for achieving appropriate alignment. In this study, we have evaluated the reliability of ‘mid-sulcus line’ as an anatomical landmark to guide tibial resection, with the intra-operative help of CANS. MethodA total of 322 patients undergoing primary TKA (excluding previously operated limbs and limbs with extra-articular deformities of tibia or femur) using CANS were included in the study. After resecting ACL, the mid-suclus line was drawn with a cautery tip. We hypothesized that if tibial cut was made perpendicular to the mid-sulcus line, coronal alignment of the tibial component would be along the neutral mechanical axis. This was evaluated intra-operatively with the help of CANS. ResultsOf 322 knees, identification of the ‘mid-sulcus line’ was possible in 312 knees. The mean angle between the tibial alignment defined by mid-sulcus line and the neutral mechanical axis was found to be 0.45° (range, 0–1.5°) (P < 0.05). In all of the 312 knees, the tibial alignment defined by mid-sulcus line was found to be within 3° of the neutral mechanical axis (confidence interval: 0.410°, 0.491°). ConclusionMid-sulcus line can be used as an additional anatomical landmark to guide the tibial resection and thereby achieve appropriate coronal alignment in primary TKAs without any extra-articular deformity.

Computer-assisted navigation for intramedullary nailing of intertrochanteric femur fractures: a preliminary result.

Aim To demonstrate a reduction of risk factors ray-depending in proximal femur nailing of intertrochanteric femur fractures, comparing standard technique with computer-assisted navigation system. Methods One hundred patients hospitalised between October 2021 and June 2022 with intertrochanteric femur fractures type 31-A1 and 31-A2 were prospectively enrolled and divided randomly into two groups. A study group was treated with computer-assisted navigation system ATLAS (Masmec Biomed, Modugno, Bari, Italy) (20 patients), while a control group received the standard nailing technique. The same intertrochanteric nail was implanted by a single senior surgeon, Endovis BA 2 (EBA2, Citieffe, Calderara di Reno, Bologna, Italy). The following data were recorded: the setup time of operating room (STOR; minutes); surgical time (ST; minutes); radiation exposure time (ETIR; seconds) and dose area product (DAP; cGy·cm2). Results Patients underwent femur nailing with computer-assisted navigation system reported more set-up time of operating room (24.87±4.58; p<0.01), less surgical time (26.15±5.80; p<0.01), less time of radiant exposure (4.84±2.07; p<0.01) and lower dose area product (16.26±2.91; p<0.01). Conclusion The preliminary study demonstrated that computerassisted navigation allowed a better surgical technique standardization, significantly reduced exposure to ionizing radiation, including a reduction in surgical time. The ATLAS system could also play a key role in residents improving learning curve.

Computer-Assisted Navigation Accurately Delivers Preoperative Targets for Acetabular Component Orientation During Direct Anterior Approach Total Hip Arthroplasty.

Despite its success, total hip arthroplasty (THA) remains associated with potentially significant complications associated with component malposition. Preoperative planning can mitigate some of these potential concerns; however, the accurate intraoperative delivery of preoperative targets can be challenging. Computer-assisted navigation may assist with intraoperative target delivery, although the integration of these two technologies is relatively uncommon. We retrospectively reviewed cases of THA planned with a computed tomography-based preoperative planning software and performed with the use of an imageless, computer-assisted navigation system. Postoperative acetabular component orientation from radiographs was compared with preoperative targets and intraoperative navigation measurements. A total of 76 patients were included in the analysis. The mean anteversion target (20.0°±3.1°) did not differ significantly from the mean intraoperative navigation measurement (20.5°±3.3°; P=.30; mean difference, 2.2°±2.3°). The mean radiographic measurement (26.6°±6.5°) differed from the target by a mean of 7.5°±6.1° (P<.001). The mean inclination target (38.4°±1.9°) did not differ significantly from the mean intra-operative measurement (38.0°±1.5°; P=.20; mean difference, 1.3°±1.7°) but differed from the radiographic measurement by a mean of 5.2°±4.2° (41.8°±5.6°; P<.001). No adverse events were reported in the 90-day period following the index procedure. Our study demonstrated that an imageless navigation system can accurately deliver computed tomography-derived preoperative targets for acetabular component orientation. Differences noted on radiographs may be due to the difference in patient positioning for the postoperative imaging (standing) as compared with preoperative imaging or surgery itself (supine). [Orthopedics. 2023;46(4):218-223.].

Cirq Robotic Assistance for Thoracolumbar Pedicle Screw Placement: Overcoming the Disadvantages of Minimally Invasive Spine Surgery.

Various minimally invasive spine surgery (MISS) techniques have been developed with the goal of reducing approach-related soft-tissue trauma and its associated complications. However, there is still a debate on some of the potential drawbacks of MISS techniques, such as their longer operating times and increased intraoperative radiation. A solution to these disadvantages could be the implementation of new technologies, such as computer-assisted navigation (CAN) and surgical robotics. We compare the standard fluoroscopy MISS technique with our experience with time per screw and X-ray exposure for pedicle screw placement using the Brainlab Cirq passive robotic arm assistance coupled with the Brainlab Curve navigation system. In the Cirq robot-assisted group (Group I), 109 screws were placed in 24 prospectively analyzed patients. In the fluoroscopy-guided group, 108 screws inserted into 20 consecutive patients were analyzed retrospectively (Group II). The duration of surgery, the time to place one screw, the X-ray exposition, and the pedicle screw accuracy for each patient were recorded and reviewed. In total, 217 screws were analyzed. The treated levels ranged from T10 to S1. In Group I, 104 screws were grade A (95.4%) and five were grade B (4.6%). In Group II, 96 screws were grade A (88.89%); ten were grade B (9.26%); one was grade C (0.93%), and one was grade D (0.93%). While the screws placed by using the Cirq system were more accurate overall, there was no statistical significance when the two groups were compared, p=0.3724. There was no significant difference in radiation exposure between the two groups, p=0.5482; however the radiation exposure for the surgeon was very limited with the Cirq system. There was a significant reduction in the operation length (p=0.0183) and the time per screw (p<0.0001) for Group I. The CAN systems and emerging robotic platforms have the potential to diminish the main disadvantages of MISS techniques-longer operation times and X-ray exposure, at least for the surgical team.

Minimally invasive anatomic reconstruction of the anterolateral ligament with ipsilateral gracilis tendon: a kinematic in-vitro study

PurposeThe anterolateral ligament (ALL) has been defined as a key stabilizer of internal tibial rotation at 35° or more of knee flexion, with a minimal primary or secondary stabilizing role in the AP direction. This study aimed to demonstrate that anatomical reconstruction of the ALL confers rotational stability equal to that of the uninjured knee. Hypothesis: anteroposterior (AP) and rotatory laxity will significantly vary after ALL tenotomy and ALL reconstruction with the author’s previously described technique.MethodsAfter ultrasound (US) ALL identification, different kinematic measurements were performed with an image-less Computer-Assisted Navigation System with dedicated software for Laxity Analysis in 5 knee specimens. Anteroposterior (AP) translations and varus/valgus (VV) and Internal-External (IE) rotations were evaluated by two trained orthopedic surgeons before ALL section, after ALL section, and after ALL anatomical reconstruction with doubled ipsilateral autologous gracilis tendon.ResultsALL resection significantly increased laxity in IE rotations with knee 90° flexed (IE90) and AP translation with tibia internally rotated and the knee 30° flexed (APlat) (p < 0.05). ALL reconstruction significantly reduced laxity in IE90 and APlat (p < 0.05) and reduced VV rotations at 30° of flexion (VV30) (p < 0.05).There were no statistically significant elongation differences between native ALL and reconstructed ALL (graft) during laxity tests. The inter-operator repeatability of the tests was excellent for each measurement.ConclusionsALL acted as an important internal tibial rotation restrain at 90° and a significant (secondary) AP stabilizer at 30° of knee flexion. The presented ALL reconstruction technique significantly restored the increase of knee laxity produced by the ALL section.Scientific levelCase-Controlled Laboratory Study, Level III.

Computer Assisted Navigation Surgery Obviates the Need of Extensive Soft Tissue Release During Total Knee Arthroplasty for Varus Knees

Introduction: We aim to (a) evaluate the kinematic patterns of varus deformities in patients with osteoarthritic knees (b) compare our result with literature published in the past and identify a valid classification scheme for the kinematic patterns of varus deformity, and (c) validate the concept of need-based soft tissue release in TKA. Methods: The computer navigations data for all those patients who underwent TKA for varus deformity was extracted and was used to assess the change in coronal plane alignment throughout the range of motion. Clinically, patient satisfaction levels were assessed by using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and functional outcomes were assessed using the Knee Society Score (KSS). Results: 120 patients satisfied the inclusion criteria set for the study. The mean age of the patients was 62.5 ± 7.09 years. The mean preoperative varus deformity was 9.5º ± 4.99o, which was correctable to a mean of 2.88º ± 2.48o in full extension. It was found that 74 (61.7%) patients had correctable varus while 46 (38.3%) had non-correctable varus. Based on the deformity pattern, the soft tissue release required was different in each group of patients. There was a statistically significant improvement both the clinical parameters (p < 0.001). Conclusion: Computer Assisted Navigation System helps to identify the dynamic nature of knee deformity before bone resections and soft tissue release. The soft tissue release for balancing the knee in varus osteoarthritic knees can be tailored sequentially according to need-base for a given pattern of deformity.

Comparison of Postoperative Enophthalmos Between Fresh and Delayed Unilateral Orbital Fractures After Orbital Reconstruction With Titanium Mesh Using Computer-Assisted Navigation.

This study compares postoperative enophthalmos between fresh and delayed unilateral orbital fractures after orbital reconstruction with titanium mesh using computer-assisted navigation. The sample was composed of 45 patients with post-traumatic unilateral enophthalmos who were divided into the fresh fracture group and the delayed fracture group. They underwent orbital reconstruction with standard preformed orbital implants and computer-assisted navigation system. The following parameters were measured with computed tomography images: the degree of enophthalmos, orbital volume, and fracture defect area. Patients were reviewed preoperatively (T0), 1 week postoperatively (T1), and 6 months postoperatively (T2). Computed tomography measurements showed that in both groups, the degree of enophthalmos decreased after surgery but increased significantly from T1 to T2 ( P <0.05). ΔE (difference in the degree of enophthalmos between T1 and T2) was similar in patients with fresh and delayed fractures. There was a significant difference in the degree of ΔE between patients with single-wall orbital fractures and those with two-wall orbital fractures. The findings indicate that postoperative enophthalmos is common in both the groups and is closely related to the degree of preoperative enophthalmos. Furthermore, the recurrence of enophthalmos is similar between the 2 groups, but it is higher in patients with orbital fractures involving 2 walls.

The accuracy of component positioning during revision total hip arthroplasty using 3D optical computer-assisted navigation.

Despite the excellent outcomes associated with primary total hip arthroplasty (THA), implant failure and revision continue to burden the healthcare system. The use of computer-assisted navigation (CAN) offers the potential for more accurate placement of hip components during surgery. While intraoperative CAN systems have been shown to improve outcomes in primary THA, their use in the context of revision total hip arthroplasty (rTHA) has not been elucidated. We sought to investigate the validity of using CAN during rTHA. A retrospective analysis was performed at an academic medical institution identifying all patients who underwent rTHA using CAN from 2016-2019. Patients were 1:1 matched with patients undergoing rTHA without CAN (control) based on demographic data. Cup anteversion, inclination, change in leg length discrepancy (ΔLLD) and change in femoral offset between pre- and post-operative plain weight-bearing radiographic images were measured and compared between both groups. A safety target zone of 15-25° for anteversion and 30-50° for inclination was used as a reference for precision analysis of cup position. Eighty-four patients were included: 42 CAN cases and 42 control cases. CAN cases displayed a lower ΔLLD (5.74 ± 7.0mm vs 9.13 ± 7.9mm, p = 0.04) and greater anteversion (23.4 ± 8.53° vs 19.76 ± 8.36°, p = 0.0468). There was no statistical difference between the proportion of CAN or control cases that fell within the target safe zone (40% vs 20.9%, p = 0.06). Femoral offset was similar in CAN and control cases (7.63 ± 5.84mm vs 7.14 ± 4.8mm, p = 0.68). Our findings suggest that the use of CAN may improve accuracy in cup placement compared to conventional methodology, but our numbers are underpowered to show a statistical difference. However, with a ΔLLD of ~ 3.4mm, CAN may be useful in facilitating the successful restoration of pre-operative leg length following rTHA. Therefore, CAN may be a helpful tool for orthopedic surgeons to assist in cup placement and LLD during complex revision cases.

The XVS System During Open Spinal Fixation Procedures in Patients Requiring Pedicle Screw Placement in the Lumbosacral Spine

This pilot study was undertaken to evaluate the safety, performance, and usability of the Xvision-Spine (XVS) System (Augmedics, Arlington Heights, IL) during open spinal fixation procedures in patients requiring pedicle screw placement in the lumbosacral spine. The XVS System is an augmented reality head-mounted display (HMD) based on a computer navigation system designed to assist surgeons in accurately placing pedicle screws. It uses an HMD-mounted tracking camera to provide optical tracking technology, and provides the surgeon a translucent direct near-eye display of the navigated surgical instrument's location relative to the computed tomographic image. We report the preliminary results of a prospective series of all consecutive patients who underwent augmented reality-assisted pedicle screw placement in the lumbosacral vertebrae at 3 institutions. Clinical accuracy for each pedicle screw was graded with Gertzbein-Robbins scores by 2 independent and blinded neuroradiologists. The 19 study participants included 8 men and 11 women with a mean age of 59.13 ± 12.09 and 59.91 ± 12.89 years, respectively. Seventeen procedures were successfully completed via the XVS System. Two procedures were not completed due to technical issues with the system's intraoperative scanner. A total of 86 screws were inserted. The accuracy of the XVS System was 97.7%. The XVS System's performance in accurate placement of pedicle screws in the lumbosacral vertebrae had an overall accuracy of 97.7%. These preliminary results were comparable to the accuracy of other manual computer-assisted navigation systems reported in the literature.