We present an analysis of manual and computer-assisted preoperative pedicle screw placement planning. Preoperative planning of 256 pedicle screws was performed manually twice by two experienced spine surgeons (M1 and M2) and automatically once by a computer-assisted method (C) on three-dimensional computed tomography images of 17 patients with thoracic spinal deformities. Statistical analysis was performed to obtain the intraobserver and interobserver variability for the pedicle screw size (i.e. diameter and length) and insertion trajectory (i.e. pedicle crossing point, sagittal and axial inclination, and normalized screw fastening strength). In our previous study, we showed that the differences among both manual plannings (M1 and M2) and computer-assisted planning (C) are comparable to the differences between manual plannings, except for the pedicle screw inclination in the sagittal plane. In this study, however, we obtained also the intraobserver variability for both manual plannings (M1 and M2), which revealed that larger differences occurred again for the sagittal screw inclination, especially in the case of manual planning M2 with average differences of up to 18.3°. On the other hand, the interobserver variability analysis revealed that the intraobserver variability for each pedicle screw parameter was, in terms of magnitude, comparable to the interobserver variability among both manual and computer-assisted plannings. The results indicate that computer-assisted pedicle screw placement planning is not only more reproducible and faster than, but also as reliable as manual planning

Introduction. Risks and benefits of bilateral total knee arthroplasty (TKA), whether simultaneous, sequential single-staged, or staged is a topic of debate. Similarly, computer-assisted navigation for TKA is controversial regarding complications, cost-effectiveness, and benefits over conventional TKA. To our knowledge, no studies have compared computer-assisted and conventional techniques for sequential bilateral TKA. We hypothesise that the computer-assisted technique has fewer complications. Methods. We retrospectively reviewed 40 computer-assisted and 36 conventional bilateral sequential TKAs from 2007–2011 with 1 year follow-up for complications. Groups were matched by age, gender, body mass index (BMI), Charlson Comorbidity Index (CCI), and American Society of Anesthesiologists Classification (ASA). Pearson's Chi-square, Fisher's exact test, and independent samples t-test were used to compare groups. Results. Our populations' mean age was 65.9 years, BMI 31.6, CCI 3.4, ASA 2.3, and a male to female ratio of 1:2. Computer-assisted demonstrated significantly better postoperative day (POD) 1 hemoglobin (p=.001), decreased number of blood transfusions (p=.001) and fewer complications (p=.023). Mean preoperative hemoglobin (Hgb) for both groups was 12.4 g/dL, but mean POD1 Hgb was 10.2 g/dL and 9.3 g/dL, for computer-assisted and conventional groups respectively. Total blood transfusion units were a mean of 1.0 and 1.7 for computer-assisted and conventional groups respectively. Seven (19%) patients in the conventional group had lethargy, altered mental status (AMS), or syncope versus none in the computer-assisted group. Subsequent Hgb levels, tourniquet time, length of stay, readmissions, and reoperations were not significantly different with numbers available between the two groups. Conclusion. Computer-assisted sequential bilateral TKAs had higher Hgb on POD1 and lower blood transfusions and complications. This may be due to violation of the femoral canal causing increased bleeding using the conventional technique. Fat emboli from the femur may have caused AMS, but did not increase incidence of pulmonary embolism in the conventional group

Introduction. Re-revision due to instability and dislocation can occur in up to 1 in 4 cases following revision total hip arthroplasty (THA). Optimal placement of components during revision surgery is thus critical in avoiding re-revision. Computer-assisted navigation has been shown to improve the accuracy and precision of component placement in primary THA; however, its role in revision surgery is less well documented. The purpose of our study was to evaluate the effect of computer-assisted navigation on component placement in revision total hip arthroplasty, as compared with conventional surgery. Methods. To examine the effect of navigation on acetabular component placement in revision THA, we retrospectively reviewed data from a multi-centre cohort of 128 patients having undergone revision THA between March 2017 and January 2019. An imageless computer navigation device (Intellijoint HIP®, Intellijoint Surgical, Kitchener, ON, Canada) was utilized in 69 surgeries and conventional methods were used in 59 surgeries. Acetabular component placement (anteversion, inclination) and the proportion of acetabular components placed in a functional safe zone (40° inclination/20° anteversion) were compared between navigation assisted and conventional THA groups. Results. Mean inclination decreased post-operatively versus baseline in both the navigation (44.9°±12.1° vs. 43.0°±6.8°, p=0.65) and control (45.8°±19.4° vs. 42.8°±7.1°, p=0.08) groups. Mean anteversion increased in both study groups, with a significant increase noted in the navigation group (18.6°±8.5° vs. 21.6°±7.8°, p=0.04) but not in the control group (19.4°±9.6° vs. 21.2°±9.8°, p=0.33). Post-operatively, a greater proportion of acetabular components were within ±10° of a functional target (40° inclination, 20° anteversion) in the navigation group (inclination: 59/67 (88%), anteversion: 56/67 (84%)) than in the control group (49/59 (83%) and 41/59, (69%), respectively). Acetabular component precision in both study groups improved post-operatively versus baseline. Variance in inclination improved significantly in both control (50.6° vs. 112.4°, p=0.002) and navigation (46.2° vs. 141.1°, p<0.001) groups. Anteversion variance worsened in the control group (96.3° vs. 87.6°, p=0.36) but the navigation group showed improvement (61.2° vs. 72.7°, p=0.25). Post-operative variance amongst cup orientations in the navigation group (IN: 46.2°; AV: 61.2°) indicated significantly better precision than that observed in the control group (IN: 50.6°, p=0.36; AV: 96.3°, p=0.04). Discussion. Re-revision is required in up to 25% of revision THA cases, of which 36% are caused by instability. This places a significant burden on the health care system and highlights the importance of accurate component placement. Our data indicate that the use of imageless navigation in revision THA – by minimizing the likelihood of outliers – may contribute to lower rates of re-revision by improving component orientation in revision THA. Conclusion. Utilizing imageless navigation in revision THAs results in more consistent placement of the acetabular component as compared to non-navigated revision surgeries

Utilization of C-arm fluoroscopy during direct anterior total hip arthroplasty (THA) is disruptive and potentially increases the risks of patient infection and cumulative surgeon radiation exposure. This pilot study evaluated changes in surgeon C-arm utilization during an initial 10 cases of direct anterior THA in which an imageless computer-assisted navigation device was introduced. This retrospective study includes data from 20 direct anterior THA cases performed by two orthopaedic surgeons (BC; SRE) in which an imageless computer-assisted navigation device was utilized (Intellijoint HIP®; Intellijoint Surgical, Waterloo, ON, Canada). Total C-arm image count was recorded in each case, and cases were grouped in sets of 5 for each surgeon. The mean C-arm image count was calculated for each surgeon, and combined C-arm image counts were calculated for the study cohort. Student's t-tests were used to assess differences. The use of intraoperative C-arm fluoroscopy decreased from a mean of 9.4 images (standard deviation [SD]: 8.6; Range: 3 – 23) to a mean of 2 images (SD: 2.9; Range: 0 – 7) for surgeon BC (P=0.10) and decreased from a mean of 10.75 images (SD: 1.2; range 9 – 12) to a mean of 6.7 images (SD: 8.3; range: 0 – 16) for surgeon SRE (P=0.36). Combined, an overall decrease in intraoperative C-arm image count from a mean of 11.3 images (SD: 6.9; range: 6 – 23) to a mean of 3.7 images (SD: 3.9; range: 0 – 8.5) was observed in the study cohort (P=0.06). The adoption of imageless computer-assisted navigation in direct anterior THA may reduce the magnitude of intraoperative C-arm fluoroscopy utilization; however further analysis is required

While double-bundle anterior cruciate ligament (ACL) reconstruction attempts to recreate the two-bundle anatomy of the native ACL, recent research also indicates that double-bundle reconstruction more closely reproduces the biomechanical properties of the ACL and restores the rotatory and sagittal stability to the level of the intact knee that was not attainable with anatomic single-bundle reconstruction. Though double-bundle reconstruction provides these potential biomechanical benefits, it poses a significant challenge to the surgeon who must attempt to accurately place twice as many tunnels while avoiding tunnel convergence compared to single-bundle reconstruction. In addition, previous work has shown that tunnel malpositioning may cause grafts that fail to reproduce the native biomechanics of the ACL, increase graft tension in deep knee flexion, increase anterior tibial translation, and produce lower IKDC (International Knee Documentation Committee) scores. We hypothesise that experienced surgeons without the use of computer-assisted navigation will place tunnels on the tibial plateau and lateral femoral condyle that more closely emulate the locations of the native anteromedial (AM) and posterolateral (PL) ACL bundles than inexperienced surgeons with the use of computer-assisted navigation. A novice surgeon group comprised of three medical students each performed double-bundle ACL reconstruction using passive computer-assisted navigation on a total of eleven cadaver knees. Their individual results were compared to three experienced orthopaedic surgeons each performing the identical procedure without the use of computer-assisted navigation on a total of nine cadaver knees. There were no significant differences in placement of either the AM or PL tunnels on the tibial plateau between novice surgeons using computer-assisted navigation and experienced surgeons without the use of computer navigation. On the lateral femoral condyle, novice surgeons placed the AM and PL tunnels significantly more anterior along Blumensaat's line on average compared to experienced surgeons. Both groups placed femoral AM and PL tunnels anterior to previously described AM and PL bundle positions. Novice surgeons utilizing computer-assisted navigation and experienced surgeons without computer assistance place the AM and PL tunnels on the tibial side with no significant difference. On the lateral femoral condyle, novice surgeons utilising computer-assisted navigation place tunnels significantly anterior along Blumensaat's line compared to experienced surgeons without the use of computer navigation

Background. Both minimally invasive surgery(MIS) and computer-assisted surgery(CAS) in total knee arthroplasty have been scientifically linked with surgical benefits. However, the long-term results of these techniques are still controversial. Most surgeons assessed the surgical outcomes with regard to knee alignment and range of motion, but these factors may not reflect subjective variables, namely patient satisfaction. Purpose. To compare satisfaction and functional outcomes between two technical procedures in MIS total knee arthroplasty, namely computer-assisted MIS and conventional MIS procedure, operated on a sample group of patients after 10 years. Methods. Seventy cases of posterior-stabilized total knee prostheses were implanted using a computer-assisted system and were compared to seventy-four cases of matched total knee prostheses of the same implant using conventional technique. Both groups underwent arthrotomy by 2 centimeter limited quadriceps exposure minimally invasive surgery (2 cm Quad MIS). At an average of ten years after surgery, self-administered patient satisfaction and WOMAC scales were administered and analyzed. Results. Demographic data of both groups including sex, age, preoperative WOMAC and post-operative duration were not statistically different. Post-operative WOMAC for the computer-assisted group was 38.94±5.68, while the conventional one stood at 37.89±6.22. The median of self-administered patient satisfaction scales of the computer-assisted group was 100 (min37.5-max100), while the conventional one was 100 (min25-max100). P-value was 0.889. There was 1 re-operative case in the conventional MIS group due to peri-prosthetic infection which was treated with debridement, polyethylene exchanged and intravenous antibiotics. Conclusion. The long-term outcomes of computer-assisted MIS total knee arthroplasty are not superior to that of the conventional MIS technique. Computer assisted MIS total knee arthroplasty is one of the treatment options for osteoarthritis of the knee that has comparable levels of satisfaction to the conventional MIS technique

Abstract Detail. Interim results on a prospective, randomised, single-blinded pilot study to compare implant alignment using a patient-matched cutting guide versus a computer-assisted navigation system following total knee arthroplasty. Purpose of Study. To compare implant alignment using a patient-matched cutting guide (Visionaire) versus a computer-assisted navigation system (CAS) following total knee arthroplasty (TKA). Description of methods. Ethics approval was sought and granted by the South African Medical Association Research Ethics Committee. Patient consent for participation was obtained. Patients were randomized to TKA using Visionaire or CAS. Mechanical alignment was evaluated pre-operatively and at 3 months with a full leg X-Ray. Operative and post-operative parameters relating to resource utilization were captured. Clinical status according to the Knee Society Clinical Rating System (KSCRS) was assessed pre-operatively and at 3 months. Adverse events were noted. An independent Contract Research Organisation was used to monitor the site. Summary of results. Ten unique patients were enrolled, of whom 5 were randomized to Visionaire and 5 to CAS. Two patients in the Visionaire group have not yet reached their 3-month assessment. No significant difference in mechanical alignment between the 2 groups at 3 months was observed. The median duration of surgery was significantly shorter for the patient-matched cutting guide group across all assessed parameters (theatre time: 117 versus 150 minutes, p=0.009; operative time: 85 versus 108 minutes, p=0.0088; tourniquet time: 73 versus 99 minutes, p=0.009; and anaesthetist time: 117 versus 150 minutes, p=0.009). No other significant differences in operative or post-operative cost-drivers were noted between the 2 groups. No significant difference in KSCRS scores between the 2 groups at 3 months was observed. Two adverse were reported, one in each group, both unrelated to the medical devices, and both of which have resolved. Conclusion. While implant alignment appears consistent and comparable in both groups at 3 months, the median duration of surgery was significantly shorter for the Visionaire group. DISCLOSURE: Assistance and funding was received from Smith & Nephew

Introduction. Computer-assisted navigation is an established tool in hip and knee arthroplasty. This technology was introduced with the goals of greater precision in bone preparation and implant placement, potentially leading to improved clinical outcomes. Various navigation protocols exist, many of which require placement of temporary percutaneous pins in the operative field. Risks of pin placement have not been described. Methods. We conducted a retrospective review of 352 consecutive patients undergoing elective hip and knee surgery using computer-assisted navigation between January 2013 and December 2015, all with a minimum follow-up of 90 days. Navigation pins were placed using a standardized protocol into the iliac crest for hip arthroplasty or into the femoral and tibial diaphysis for knee arthroplasty. Postoperatively, all patients were allowed to weight bear as tolerated. Patient records were reviewed for operative details and clinical outcomes. Outcome measures included any pin site complications including direct neurovascular damage, fracture through a pin site, and pin site infection. Results. A total of 968 pin sites were included in the study. Two pin site complications were reported (0.21%). No neurovascular injuries were reported from pin placement (0.0%). No periprosthetic fractures through a pin site were reported (0.0%). Two patients developed a pin-site infection with purulent drainage (0.21%), both of which resolved with oral antibiotics and local wound care. Conclusion. Potential benefits of navigation in hip and knee arthroplasty are still being investigated, however the placement of pins required for this technology are associated with minimal patient morbidity and should be considered a safe intervention with minimal added risk

Introduction:. Computer-assisted surgery (CAS) aims to improve component positioning and mechanical alignment in Total Knee Arthroplasty (TKA). Robotic cutting-guides have been integrated into CAS systems with the intent to improve bone-cutting precision and reduce navigation time by precisely automating the placement of the cutting-guide. The objectives of this study were to compare the intra-operative efficiency and accuracy of a robotic-assisted TKA procedure to a conventional computer-assisted TKA procedure where fixed sequential cutting-blocks are navigated free-hand. Methods:. This was a retrospective study comparing two distinct cohorts: the control group consisted of patients undergoing TKA with conventional CAS (Stryker Universal Knee Navigation v3.1, Stryker Orthopaedics, MI) from May 2006 to September 2007; the study group consisted of patients undergoing TKA with a robotic cutting-guide (Apex Robotic Technology, ART, OMNIlife Science, MA) from October 2010 to May 2012. Exclusion of patients with preexisting hardware in the joint or an absence of navigation data resulted in a total of 29 patients in the control group and 52 patients in the study group. Both groups were similar with respect to BMI, age, gender, and pre-operative alignment. All patients were operated on by a single surgeon at a single institution. The navigation log files were analyzed to determine the total navigation time for each case, which was defined as the time from the start of the acquisition of the hip center to the end of the final alignment analysis for both systems. The intraoperative final mechanical axis was also recorded. The tourniquet time (time of inflation prior to incision to deflation immediately after cement hardening) and hospitalization length were compared. Linear regression analysis was performed using R statistical software v2.12.1. Results:. Navigation times were on average 9.0 minutes shorter in the study group compared to the control group (95% CI: [4.0, 14.1], p = 0.0006). Average absolute intraoperative alignment was 0.5 degrees closer to neutral in the robotic group compared to the conventional CAS group (95% CI: [0.08, 0.95], p = 0.020). Tourniquet time was not significantly different between the two systems (0.2 min, 95% CI [−5.4, 5.9], p = 0.926). Patients in the study group were discharged 0.6 days earlier than patients in the control group (95% CI: [0.1, 1.1], p = 0.0122). Discussions:. Our results suggest that use of a robotic cutting-guide can decrease the time taken to navigate a TKA procedure in comparison to conventional free-hand navigation of multiple fixed cutting blocks, which is supported by previous studies [1]. However, this time savings did not translate into a reduction in the tourniquet time. We believe this may be due in part to the two different types of bone cement that were used during the distinct study periods, where the hardening time for the cement in the study group was estimated to be approximately 5 minutes longer. Conclusions:. In one surgeon's hands, use of a robotic cutting-guide decreased navigation time, improved intraoperative final alignment, and decreased hospitalization length when compared to conventional computer-assisted navigation in TKA

Proper positioning of the acetabular cup deters dislocation after total hip arthroplasty (THA) and is therefore a key focus for orthopedic surgeons. The concept of a safe zone for acetabular component placement was first characterized by Lewinnek et al. and furthered by Callanan et al. The safe zone concept remains widely utilized and accepted in contemporary THA practice; however, components positioned in this safe zone still dislocate. This study sought to characterize current mass trends in cup position identified across a large study sample of THA procedures completed by multiple surgeons. This retrospective, observational study reviewed acetabular cup position in 1,236 patients who underwent THA using computer-assisted navigation (CAS) between July 2015 and November 2017. Outcomes included acetabular cup position (inclination and anteversion) measurements derived from the surgical navigation device and surgical approach. The overall mean cup position of all recorded cases was 21.8° (±7.7°, 95% CI = 6.7°, 36.9°) of anteversion and 40.9° (±6.5°, 95% CI = 28.1°, 53.7°) of inclination (Table 1). For both anteversion and inclination, 65.5% (809/1236) of acetabular cup components were within the Lewinnek safe zone and 58.4% (722/1236) were within the Callanan safe zone. Acetabular cups were placed a mean of 6.8° of anteversion (posterior/lateral approach: 7.0°, anterior approach: 5.6°) higher than the Lewinnek and Callanan safe zones whereas inclination was positioned 0.9° higher than the reported Lewinnek safe zone and 3.4° higher than the Callanan safe zone (Figure 1,2). Our data shows that while the majority of acetabular cups were placed within the traditional safe zones, the mean anteversion orientation is considerably higher than those suggested by the Lewinnek and Callanan safe zones. The implications of this observation warrant further investigation. For any figures or tables, please contact the authors directly

Introduction. The aim of our study was to compare the radiographic alignment unicompartmental knee arthroplasty (UKA) with using conventional non-navigation technique and computer-assisted navigation technique. Our study was focused on bearing alignment on clinical outcome of knee. Materials and Methods. In our department we have performed between January 2005 and December 2012 106 UKA. All patients were examined clinically and radiologically before and after operation. There were implanted two types of UKA, 67 of UKA were performed by The PRESERVATION™ (DePuy) with navigation and 39 UKA Oxford® Partial Knee (Biomet.) were performed by conventional technique. In our study we have evaluated 104 of medial UKA divided to groups, 65 implantation of The PRESERVATION™ and 39 implantation of Oxford® Partial Knee UKA. We have evaluated 101 patients, 61 women, 40 men, average age 66,5 (50–82) years. Firstly we performed measurement of parameters determine alignment UKA. These values were written down and the deviation of norm was established. Results were divided in two groups, one with values of normal range and the second beyond normal range. Values of all UKA were matched with clinical outcome postoperatively. This assessment was performed by The Knee Society Clinical Rating System (Knee score). Results. The mean follow-up was 3,3 (max. 7,1) years. The group with navigation technique improved Knee score from mean 58 (41–79) preoperatively to 93 (62–100) postoperatively. Conventional UKA Knee score improved from 56 (39–77) preoperatively to 91 (61–100) postoperatively. Clinical outcome is comparable in both groups. Radiological assessment of alignment unicompartmental knee replacement according to our measurement results in favour of computer-assisted navigation. Conclusion. Computer-assisted navigation enables more exact alignment of the femoral and tibial component than conventional technique. In spite of the fact that difference clinical outcome is comparable

Introduction. The aim of this study was to assess the accuracy of aligning the cup with the transverse acetabular ligament (TAL) in total hip arthroplasty (THA) and the reproducibility of this procedure by using computer-assisted navigation. Methods. Between January 2011 and March 2012, 75 patients (81 hips) underwent primary THA using the posterolateral approach at our hospital. We excluded 4 hips with a history of pelvic osteotomy; thus, the study included 77 hips. We measured the anatomical anteversion of the TAL intraoperatively by aligning the inferomedial rim of the cup trial with the TAL using computer-assisted navigation. We set the abduction to 45° at measure of the anteversion of the TAL. Measurements for each hip were independently performed thrice by 2 surgeons chosen among 1 expert and 6 non-experts. The surgeon performing the measurement was blinded during this process; the navigation screen was turned away from the surgeon's field of view. Anatomical inclination and anteversion were measured with reference to the functional pelvic plane. The intraclass correlation coefficient (ICC) was used to assess intra- and inter-observer reliability. The mean value of all 6 measurements was used to determine the anteversion of the TAL in each hip. Results. The TAL was identified in 83% of the cases (64 of 77 hips). Intra-observer reliability was high for both the expert surgeon (ICC(1.1) = 0.851) and the non-expert surgeons (ICC(1.1) = 0.825). Inter-observer reliability was moderate (ICC(2.1) = 0.452). The mean difference in the anatomical anteversion measured by 2 surgeons was 7.0° (5.3°) (range, 0.3–21.3°). The mean anatomical anteversion of the TAL was 20.9° (7.0°) (range, 9.0–48.3°). Discussion and Conclusions. Recently, reports have suggested that the TAL can be used as a reference for determining a patient's native acetabular anteversion; the position of the cup can then be customized so that the face of the acetabular component is parallel to the TAL. We measured the anatomical anteversion of the cup trial aligned with the TAL using computer-assisted navigation and assessed the reproducibility of the alignment. Intra-observer reliability was high, and each surgeon was able to align the cup according to his target for of the TAL anteversion. However, inter-observer reliability was only moderate. This is because the TAL is a short ligament with some thickness, and the methods employed to align the cup trial with the TAL may differ among surgeons. The smallest anteversion of the TAL was 9°, and retroversion was not observed in any of the cases. Therefore, in our opinion, the TAL is useful as a reference for not positioning the cup in retroversion. However, in some cases with an excessive posterior pelvic tilt, the anteversion of the TAL may have been excessive and not necessarily optimal. Therefore, aligning the cup with TAL may not be the ideal method for all cases

Background. Effectiveness of computer-assisted joint replacement (CA-TJR) compared to conventional TJR has been evaluated by a large body of literature. Systematic reviews provide a powerful, widely accepted, evidence-based approach to synthesize the evidence and derive conclusions, yet the strength of these conclusions is dependent on the quality of the review. Multiple systematic reviews compared CA-TJR and conventional TJR with conflicting results. We aimed to assess the quality of these reviews. Methods. We searched MEDLINE, EMBASE, the Cochrane, and Epistemonikos to identify SRs published through May 2017. Full-text articles that met inclusion criteria were retrieved and assessed independently by two reviewers. Evidence was qualitatively synthesized and summarized. Outcome measures were categorized into functional, radiological, and patient safety related. The corrected covered area (CCA) was calculated to assess the degree of overlap between SRs in analyzing the same primary studies. The AMSTAR 2, a valid and reliable tool, was applied to rate the confidence in the results of the SRs (Shea et al., 2017). AMSTAR-2 has 16 domains, of which 7 are critical (e.g., justification for excluding individual studies) and 9 are non-critical (e.g., not reporting conflict of interest for individual studies). Reviews are rated as high (no critical or non-critical flaws), moderate (only non-critical flaws), low (1 critical flaw) and critically low (more than one critical flaw). Disagreement between the 2 reviewers was resolved by discussion with the senior author to achieve consensus. We reported the quality ratings of these studies and the frequency of critical and non-critical flaws. Results. Of 384 citations originally identified, 37 systematic reviews were included. Meta-analyses that addressed TKA showed discrepancy on functional (e.g. KSS), radiological (mechanical axis malalignment), and patient safety (e.g. adverse events) outcomes. Meta-analyses that addressed THA showed more consistent results. Moderate overlap was observed among TKA SRs (CCA=7%) and very high overlap among THA SRs (CCA=26%). Based on the AMSTAR 2 tool, 35 studies were rated critically low and two studies were rated low. Low rating was due to failure in: developing a review protocol (94.6%); using a comprehensive search strategy (56.8%), providing a list of excluded studies (89%); accounting for risk of bias in the primary RCTs (44%), accounting for the risk of bias of the primary studies when discussing the results (70%), performing appropriate statistical methods (53% for RCTs and 88% for non-RCTs), and adequately investigating publication bias (53%). Conclusions. Given the very low confidence in the results of the SRs comparing CA to conventional total joint arthroplasty, clinicians should interpret the results of these SRs with caution. High methodological quality SRs are needed to inform evidence-based clinical practice

Background. Accurate insertion of pedicle screws in scoliosis patients is a great challenge for surgeons due to the severe deformity of thoracic and lumbar spine. Meanwhile, mal-position of pedicle screw in scoliosis patients could lead to severe complications. Computer-assisted navigation technique may help improving the accuracy of screw placement and reducing complications. Thus, this meta-analysis of the published researches was conducted concentrating on accuracy of pedicle screw placement and postoperative assessment in scoliosis patients using computer-assisted navigation technique. Methods. PubMed, Cochrane and Web of Science databases search was executed. In vivo comparative studies that assessed accuracy and postoperative evaluation of pedicle screw placement in scoliosis patients with or without navigation techniques were involved and analysed. Results. One published randomised controlled trial (RCT) and seven retrospective comparative studies met the inclusion criteria. These studies included 321 patients with 3821 pedicle screws inserted. Accuracy of pedicle screw insertion was significantly increased with using of navigation system, while average surgery time was not significantly different with non-navigated surgery. And Correction rate for scoliosis in navigated surgery was not significantly different with non-navigated surgery. Conclusions. Navigation technique does indeed improve the accuracy of pedicle screw placement in scoliosis surgery, without prolong the surgery time or decrease the deformity correction effect

Introduction. Correct postoperative leg length restoration is among the most important goals of hip arthroplasty. Therefore, we developed, validated and clinically applied a novel software algorithm based on surgical navigation, which allows the surgeon to restore a defined femur position without establishing a femoral coordinate system or the hip joint center and measure the leg length accurately and simply. Material and Methods. This new leg length algorithm was used in 154 hips (145 patients) that underwent CT-based computer-assisted THA (VectorVision Build 274 prototype; BrainLAB AG, Helmstetten, Germany) with a tissue preserving superior capsulotomy. Intraoperatively, a pelvic and a femoral dynamic reference bases (DRB) were applied and the anterior pelvic plane (APP) was set as the pelvic coordinate system. Then, the hip joint was put in a neutral position and this position, and the relative position of the femoral DRB relative to the pelvic DRB, was captured and stored by the navigation system. After implantation of the prosthesis the same above described femoral position with the same amplitude of flexion/extension, abduction/adduction and rotation was restored. Now, any resulting difference was due to linear changes. Validation of this new algorithm was performed by comparing the navigated results to measurements from calibrated antero-posterior pre- and postoperative radiographs. The radiographic results were compared to the mean leg length change measured with the navigation system. Results. No significant difference was found between radiographic leg length change and the results from the navigation system (p=0.658). The mean difference between the radiographic results and the results from the navigation system was −0.5 (1–8 mm (range, −5–4 mm). The mean registration accuracy of the navigation system was 2.04 (0.58 mm (range, 0.70–3.00 mm). Discussion. This novel tool has the potential to increase the accuracy and consistency of leg-length change measurement during hip arthroplasty. Improved methods of measuring leg length change during surgery are even more critical now, when smaller incisions are being used, because traditional mechanical measurement methods are potentially even more unreliable than they are when larger exposures are used. This current method of measuring leg length change eliminates the need to calculate the center of rotation of the arthritic hip joint, which is often not accurately possible, and eliminates the need to establish a femoral coordinate system, which can be time consuming and frustrating. Besides registration accuracy, validation with plain radiographs is another potential source of error. Nonetheless, there was a substantial agreement between the radiographic results and the results from the navigation system. This novel computer-assisted method represents an accurate and simple tool for intraoperative leg length measurement

Orthopaedic surgery residents typically learn total knee arthroplasty (TKA) through an apprenticeship-type model, which is a necessarily slow process. If residents could learn the required technical and cognitive skills more quickly, they could make better use of reduced hours in the operating room, surgeons could teach at a higher level, patients could have shorter operating times with better outcomes, and the healthcare system would have reduced costs and better-trained surgeons. Surgical skills courses, using artificial bones, have been shown to improve technical and cognitive skills significantly within a couple of days. Computer-assisted surgery (CAS) provides real-time feedback and component position planning, leading to improved alignment and a shorter learning curve. Combining these two approaches challenges the participants to consider the same task in different contexts, promoting cognitive flexibility. We designed a hands-on educational intervention for junior residents incorporating a conventional tibiofemoral TKA station, two different tibiofemoral CAS stations and a conventional and CAS patellar resection station. The same implant system was used in all cases. Both qualitative and quantitative analyses were performed. Qualitatively, structured interviews before and after the course were analysed for recurring themes. Quantitatively, subjects were evaluated on their technical skills in a timed conventional TKA test before and after the course, and on their knowledge and error-detection skills after the course. Their performance was compared to senior residents who performed only the testing. Four themes emerged: increased confidence, improved awareness, deepening knowledge and changed perspectives. The residents' attitudes to CAS changed from negative before the course to neutral or positive after the course. They expected it to be difficult to use and found that it was easy. They originally distrusted the system, but came to think they would use it for their most difficult cases. The junior resident group improved their task completion rate from 23% to 75% of tasks (p<0.01), compared to 45% of tasks completed by the senior resident group. As a result of the course, the residents will be more aware what to focus on in the operating room. High impact educational interventions, promoting cognitive flexibility and including real-time feedback from computer-assisted surgery simulations, would benefit trainees, surgeons, the healthcare system and patients

Osteotomies for valgus deformity are much less frequent than those for varus deformity as evidenced by published series which are, on one hand, less numerous and on the other hand, based on far fewer cases. For genu varum deformity, it has been proved that navigation allows to reach easier the preoperative correction goal. Our hypothesis was that navigation for genu valgum could be as accurate as for genu varum deformity. The aim of this paper was to present the mid-term results of 29 computer-assisted osteotomies for genu valgum deformity performed between September 2001 and March 2013. The series was composed of 27 patients (29 knees), 20 females and 7 males, aged from 15 to 63 years (mean age: 42.4+/−14.3 years). The preoperative functional status was evaluated according to the Lyshölm-Tegner score. The mean score was of 64+/−20.5 points (18–100). The stages of osteoarthritis were evaluated according to modified Ahlbäck's criteria. We operated on 12 stage 1, 9 stage 2, 5 stage 3 and 1 stage 4. 2 female patients had no osteoarthritis but a particularly unesthetic deformity (of which one was related to an overcorrected tibial osteotomy). The pre and postoperative HKA angle was measured according to Ramadier's protocol. We measured also the medial tibial mechanical angle (MTMA) and the medial femoral mechanical angle (MFMA). The mean preoperative HKA angle was 189.3°+/−3.9° (181° to 198°); the mean MFMA was 97.2° +/− 2.6° (93° to 105°) and the mean MTMA was 90.1° +/− 2.8° (86° to 95°). The goal of the osteotomies was to obtain an HKA angle of 179° +/− 2° and a MTMA of 90°+/2° in order to avoid an oblique joint line. We performed 24 femoral osteotomies (14 medial opening wedge and 10 lateral closing wedge) and 5 double osteotomies (medial tibial closing wedge + lateral opening wedge osteotomy). The functional results were evaluated according to Lyshölm-Tegner, IKS and KOO Scores, which were obtained after revision or telephone call. We did not find any complication except a transient paralysis of the common fibular nerve. 23 patients (4 lost to follow-up) were reviewed at a mean follow-up of 50.9+/−38.8 months (6–144). The mean Lyshölm-Tegner score was 92.9+/−4 points (86–100), the mean KOO score 89.7+/−9.3 (68–100), the mean IKS ≪knee≫ score 88.7 +/−11.4 points (60 à 100) and the mean ≪function≫ score 90.6 +/−13.3 points (55–100). 22 of the 23 reviewed patients (25 knees) were very satisfied or satisfied of the result. Regarding the radiological results, the mean HKA angle was of 180.1°+/−1.9° (176° to 185°), the mean MFMA of 90.7°+/−2.5° (86°-95°) and the mean MTMA of 89.1°+/−1.9° (86°-92°). The preoperative goal was reached in 86.2% (25/29) of the cases for HKA angle and in 100% of the cases for MTMA when performing double level osteotomy (5 cases). At this follow-up, no patient was revised to TKA. Computer-assisted osteotomies for genu valgum deformity lead to excellent results a mid-term follow-up. Navigation is very useful to reach the preoperative goal

Objective. Computer-assisted minimally invasive total knee arthroplasty (CAMI-TKA) has gained increasing interest from orthopaedic surgeons due to its advantages in improving accuracy of component placement combined with benefits in postoperative recovery due to a smaller incision. However, long-term clinical and radiographic outcomes are lacking. The purpose of the present study is to compare the long-term radiographic features and functional outcomes between patients who underwent CAMI-TKA and those who underwent conventional TKA. Methods. One hundred and eight patients who were randomized to undergo CAMI-TKA or conventional TKA during 2004 and 2005 were contacted by phone for a prospective follow-up review. Patients who have passed away or declined to participate in the study were excluded. Patients were asked to return to the hospital for clinical and functional assessments, long-leg and knee roentgenograms. Baseline characteristics were compared to account for potential confounders and multivariate statistical analysis applied to account for any differences in baseline characteristics. Results. As shown in Figure 1, a total of 101 patients (93.52%) were contacted, and 69 patients (63.89%) returned to hospital for assessments and investigations. By the time of this study, two patients from the Conventional TKA group had undergone revision TKA, one due to infection and one due to aseptic loosening. The average follow up time was 9.07 years (8.51–9.61 years). Subsequent comparison was carried out between 37 patients from the conventional TKA group and 30 from the CAMI-TKA group. Both groups had similar pre-operative demographics, clinical and functional assessments except for the Function Score component of the Knee Society Score (Conventional=50 vs. CAMI=55, p=0.049). At follow-up, the Short Form-36 and Knee Society Scores were comparable between the two groups. However, patients from CAMI group reported a significantly higher Oxford Knee Score compared to those from conventional group (p=0.013). No significant intergroup differences were found in mechanical knee alignment and component placement angle in the coronal views. In the sagittal views, the femoral components demonstrated a more extensional configuration in the conventional group, in contrary to a more flexional configuration in the CAMI group (1.0° extension vs. 1.5° flexion, p<0.001). There also existed a significant difference in sagittal tibial component angles, where the conventional group had a steeper posterior slope compared to the CAMI group (5.1° vs. 2.5°, p=0.002). Four knees from CAMI-TKA group and 1 knee from Conventional TKA group were found to have non-progressive radiolucencies between the components and bone cuts, without statistical or clinical significance. No other patients demonstrated any migrating or shifting of the prosthesis that could be construed as possible failure in either group. Conclusions. Computer-assisted minimally invasive total knee arthroplasty provided similar clinical, functional, and radiographic outcomes compared with conventional total knee arthroplasty after an average of 9 years follow-up. This technique can be employed to exploit its short-term advantages without compromising long-term clinical and radiographic outcomes

Purpose. Primary internal fixation of uncomplicated scaphoid fractures offers many advantages compared to conventional casting. However, ideal fixation placement along the central scaphoid axis can be challenging, especially if the procedure is performed percutaneously. Because of the lack of direct visualization, percutaneous procedures demand liberal use of imaging, thereby increasing exposure to harmful radiation. It has been demonstrated that computer-assisted navigation can improve the accuracy of guidewire placement and reduce X-ray exposure in procedures such as hip fracture fixation. Adapting the conventional computer-assist paradigm, with preoperative imaging and intraoperative registration, to scaphoid fixation is not straightforward, and thus a novel tactic must be conceived. Method. Our navigation procedure made use of a flatpanel C-arm (Innova, GE Healthcare) to obtain a 3D cone-beam CT (CBCT) scan of the wrist from which volumetrically-rendered images were created. The relationship between the Innova imager and an optical tracking system (OptoTrak Certus, Northern Digital Inc.) was calibrated preoperatively so that an intraoperatively-acquired image could be used for real-time navigation. Optical markers fitted to a drill guide were used to track its orientation, which was displayed on a computer monitor relative to the wrist images for navigation. Randomized trials were conducted comparing our 3D navigated technique to two alternatives: one using a standard portable C-arm, and the other using the Innova flatpanel C-arm with 2D views and image intensification. A model forearm with an exchangeable scaphoid was constructed to provide consistency between the trials. The surgical objective was to insert a K-wire along the central axis of a model scaphoid. An exposure meter placed adjacent to the wrist model was used to record X-ray exposure. Procedure time and drill passes were also noted. CT scans of the drilled scaphoids were used to determine the shortest distance from the drill path to the scaphoid surface. Results. The closest distance from the drill path to the scaphoid surface was significantly larger using navigation compared to the 2D Innova method (p<0.05). Fewer drill passes were required using navigation compared to a conventional C-arm (p<0.01). Navigated procedures were significantly longer, although the overall time remained clinically acceptable (∼4min). There was no significant difference in radiation exposure to the patient between the three methods. The 3D CBCT image was acquired remotely in the navigated approach, so conceivably the exposure to the surgeon was much less than the other techniques. Conclusion. Computer-assisted navigation was successfully adapted to percutaneous scaphoid fixation without requiring the tedious preoperative imaging and intraoperative registration that typically plague these procedures. Navigation resulted in superior central screw placement with fewer drilling attempts in comparison to conventional techniques

Introduction. From pre-operative planning to final implant cementation, total knee arthroplasty (TKA) preparation is a succession of many individual steps, each presenting potential sources of error that can result in devices being implanted outside the targeted range of alignment. This study assessed alignment discrepancy occurring during different TKA steps using an image-free computer-assisted orthopaedic surgery (CAOS) guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) in normal and abnormal mechanical axis. Materials and methods. We used a commercially available artificial leg (MITA trainer leg M-00058, Medical Models, Bristol, UK) able to receive (neutral / varus / valgus) knee inserts simulating the proximal tibia and distal femur. A pre-surgical profile was established to define resection parameters for the proximal tibial and distal femoral cuts (Figure 1A). Data from the guidance system were collected at three separate steps: (1) cutting block adjusted but not pinned to the bone (Figure 1B), (2) cutting block adjusted and pinned to the bone (Figure 1C), and (3) after the cuts were checked (Figure 1D). These data were then compared to the resection target parameters to track potential dispersions occurring during the process. Due to the amount of data (i.e., four studied resection parameters per bone, three operative steps, and three knee model types), the authors introduced an “error index”, which was a unitless indication of overall error magnitude obtained by averaging the absolute values of all linear and angular measurement errors. Due to knee model dimensions (∼55 mm), the authors equally considered linear and angular measurement values (i.e., 1 mm equivalent to 1°). Results. Regardless of resection parameter or bone deformity type, all linear or angular error distributions were symmetrical around the neutral value, which implies no obvious skew in terms of error direction. The type of knee model deformity had almost no effect on overall error magnitudes throughout all surgical steps (Figure 2). Discussion. Few studies present possible causes for errors when using CAOS for TKA. Notably, Bathis et al. evaluated cutting errors as the difference between the primary cutting block position and the resulting resection plane. As a result, errors due to a malpositioning of the guide jig itself were not described. 1. In general, the authors found the dispersions at each step to seemingly be random. For both the tibia and the femur, a significant increase in the error index from the adjusted to the attached step (p<0.001 and p=0.005; respectively) was observed, meaning the pinning of the cutting block to the bone is a key step. Also, observing the relationship between linear and angular parameters was relevant. For example, for the femur, a cut in extension was highly correlated with lower than expected distal femoral resection (Pearson correlation factor of 0.783 and 0.913 at the checked step for the medial and lateral distal femoral resections; respectively, p<0.001). Regardless of the presence and type of deformity, the evaluated image-free computer-assisted guidance system did not exhibit substantial alignment dispersions during any step of the procedure