Navigated total knee replacement. A meta-analysis

Imageless optical navigation system is clinically valid for total knee arthroplasty

Achieving optimal implant position and orientation during total knee arthroplasty (TKA) is a pivotal factor in long-term survival. Computer-assisted navigation (CAN) has been recognized as a trusted technology that improves the accuracy and consistency of femoral and tibial bone cuts. Imageless CAN offers advantages over image-based CAN by reducing cost, radiation exposure, and time. The purpose of this study was to evaluate the accuracy of an imageless optical navigation system for TKA in a clinical setting. Forty-two consecutive patients who underwent primary TKA with CAN were retrospectively reviewed. Femoral and tibial component coronal alignment was assessed via post-operative radiographs by two independent reviewers and compared against coronal alignment angles from the CAN. The primary outcome was the mean absolute difference of femoral and tibial varus/valgus angles between radiograph and intra-operative device measurements. Bland-Altman plots were used to assess agreement between the methods and statistically analyze potential systematic bias. The mean absolute differences between navigation-guided cut measurements and post-operative radiographs were 1.16 ± 1.03° and 1.76 ± 1.38° for femoral and tibial alignment respectively. About 88% of coronal measurements were within ±3°, while 99% were within ±5°. Bland-Altman analysis demonstrated a bias between CAN and radiographic measurements with CAN values averaging 0.52° (95% CI: 0.11°-0.93°) less than their paired radiographic measurements. This study demonstrated the ability of an optical imageless navigation system to measure, on average, femoral and tibial coronal cuts to within 2.0° of post-operative radiographic measurements in a clinical setting.

[New technologies in total knee arthroplasty : Current concepts and personalized treatment strategies]

BACKGROUND

In total knee arthroplasty (TKA), there is a trend towards personalized concepts. This includes the implementation of new technologies and the increasing popularity of individualized alignment strategies.

TARGETS

The purpose of personalized TKA is to restore the patient's bony anatomy and constitutional alignment, as well as the physiological soft tissue balance and joint kinematics. Modern technologies facilitate a thorough, three-dimensional analysis of the bony structures and the patient's constitutional alignment. Virtual planning enables a simulation component placement, gap balancing and postoperative alignment. After approval of the surgical plan, the technology-aided execution shows a greater accuracy, precision and reproducibility of implant alignment compared to conventional manual instrumentation.

OVERVIEW

This article focuses on novel technologies in total knee arthroplasty, including patient-specific instrumentation (PSI), custom implants, navigation and robotics. The purpose of this article is to summarize current evidence, including radiological and functional outcomes, as well as economic aspects. Furthermore, the implementation of novel technologies in the context of personalized alignment strategies will be discussed.

Comparing trends and outcomes of minimally invasive transforaminal lumbar interbody fusion (TLIF) procedures: A retrospective analysis

Purpose

To describe utilization patterns of minimally invasive transforaminal lumbar interbody fusion (TLIF) procedures and to evaluate indirect healthcare utilization indicators such as revisions, infection, and complication rates for various TLIF techniques.

Methods

A retrospective analysis using the Pearldiver database was conducted to identify patients who underwent TLIF between 2010 and 2022. The patient population was stratified into four groups: TLIF with an open approach (TLIF-Open), TLIF with stereotactic navigation (TLIF-NAV), TLIF with the assistance of an operating microscope (TLIF-MI), and TLIF utilizing navigation and operating microscope (TLIF-Combined). Revision, infection, and complication rates were analyzed and compared between each technique with open procedure as the reference procedure using multivariate analysis.

Results

Over the past 13 years, TLIF-Open procedures showed a consistent decrease in utilization, while TLIF-NAV, TLIF-MI, and TLIF-Combined approaches remained relatively stable without experiencing the same dramatic increase as the decline in TLIF-Open procedures. Multivariate regression analysis revealed, TLIF-NAV and TLIF-MI procedures were associated with a higher likelihood of undergoing revision surgeries within 30 days post-operatively, with TLIF-NAV also being linked to a higher risk of infection within 30 days. The TLIF-MI group had a lower likelihood of acute kidney injury (AKI), while the TLIF-NAV group had a lower likelihood of pneumonia and urinary tract infections (UTI).

Conclusion

There has been a noticeable shift in the utilization of TLIF procedures from open to minimally invasive approaches. While stereotactic navigation demonstrates favorable outcomes in terms of complications, surgeons must carefully consider infection risks and revision rates.

The Impact of Diagnosed Chronic Sleep Disorders on Outcomes Following Total Knee Arthroplasty

BACKGROUND

Up to 20% of patients undergoing total knee arthroplasty (TKA) remain dissatisfied with their outcome, leading to the identification of risk factors for poor outcomes. The purpose of this study was to analyze the effect of chronic sleep disorders on patient-reported outcomes after primary TKA.

METHODS

A retrospective review of patients undergoing primary TKA was conducted using a prospectively collected database of patients from a single institution between 2018 and 2022. The cohort was split based on the presence of documented chronic sleep disorders, identified preoperatively from the electronic medical record using current procedural terminology codes. The sample was further restricted to include all patients who have sleep disorders (SDs), as well as a 3:1 propensity-matched (on age, sex, body mass index, and American Society of Anesthesiologists class) cohort of patients who had no documented SDs (NSDs) prior to surgery. The final sample included 172 patients (SD: 43; NSD: 129). Repeated-measures linear mixed model analysis was used to analyze the progression of Knee Injury and Osteoarthritis Outcome Score (KOOS) through time between groups.

RESULTS

Those who had SDs had a lower preoperative mean total KOOS score (40.2) than the NSD group (44.1); however, this was not significantly different (P = .108). At 1 year postoperatively, those who had an SD had a significantly higher mean total KOOS score (87.2) than the NSD group (80.4), P = .005. When comparing total KOOS scores by group, over each time period, the SD group showed a better progression when compared to the NSD group, P = .001.

CONCLUSIONS

Compared to patients who did not have documented chronic sleep disorders, patients who had a prior history of chronic sleep disorders reported significantly greater improvements in most KOOS domains in the 12-month period following TKA.

The top 100 most-cited total knee arthroplasty publications

The object is to objectively identify the 100 most influential scientific publications in total knee arthroplasty (TKA) and provide an analysis of their main characteristics. The Clarivate Analytics Web of Knowledge database was used to obtain data and metrics of TKA research. The search list was sorted by the number of citations, and articles were included or excluded based on relevance to TKA. The information extracted for each article included author name, publication year, country of origin, journal name, article type, and the level of evidence. These 100 studies generated a total of 35,399 cita- tions, with an average of 355.9 citations per article. The most-cited article was cited 1273 times. The 100 studies included in this analysis were published between 2000 and 2017. 23 different journals published these 100 publications. Majority of the publications were from United States (n = 52), followed by UK (n = 10) and Canada (n = 8). The most prevalent study designs were case series (n = 32) and cohort studies (n = 30). The 100 most influential articles in TKA were cited a total of 35,399 times. The study designs most prevalent were case series and cohort studies. This article serves as a reference to direct orthopedic surgeons to the 100 most influential studies in total knee arthroplasty. More than half of the studies are from North America, and three journals hold two-thirds of the 100 most cited publications on the topic.

Methodological Assessment of the 100 Most-Cited Articles in Total Knee Arthroplasty in the Last Decade Compared to the All-Time List

BACKGROUND

Recent advances in total knee arthroplasty (TKA) have been driven by a growing focus on evidence-based medicine. This transition is reflected in the critical appraisal of both, the quality of work and the potential impact on the orthopedic community. The purpose of our study was to (1) identify the top 100 most-cited articles in TKA in the last decade and from all-time, and (2) compare methodological rigor of the most-cited articles in TKA in the last decade to articles all-time by level of evidence.

METHODS

The top 100 cited articles were recorded for manuscripts from the last decade, January 1, 2012 to December 31, 2022, and manuscripts from all-time for TKA. We collected authors, year of publication, journal of the article, country of origin of authors, article type (basic science article, clinical research article), level of evidence, methodological index for non-randomized studies score, physiotherapy evidence database scale, and citation density (total citations/years published).

RESULTS

The largest number of studies for all-time TKA (53.0%) and decade TKA (42.0%) were Level III. The average methodological index for non-randomized studies score for comparative studies was 18.7 for all-time TKA and 20.7 for decade TKA (P < .001). The average physiotherapy evidence database score was 6.1 for all-time TKA and 8.1 for decade TKA (P > .05). The highest citation density for all-time TKA was 111 and for past decade was 63. The number of level II studies in TKA increased from 19.0% from all time to 38.0% from the last decade (P < .05).

CONCLUSIONS

Our findings of improved methodologies over time reflect positive steps toward evidence-based practice in TKA. A continued focus on producing methodologically sound studies may guide evidence-based clinical decision-making.

Restoration of constitutional alignment optimizes outcomes of computer navigated total knee arthroplasty: a prospective randomized controlled trial

PURPOSE

The value of computer navigation in total knee arthroplasty (TKA) for arthritic knees continues to be debated. The purpose of this study was to evaluate the value of navigated TKA associated with updated alignment philosophy.

METHODS

This prospective randomized controlled trial enrolled 38 consecutive patients (76 knees) and were randomly assigned to both groups. The demographic data and perioperative data were recorded. The coronal plane alignment of the knee (CPAK) classification was used to classify knee alignment phenotypes. Radiographic outcomes were measured and subgroup analysis was further performed. Clinical outcomes were evaluated using patient-reported outcome measures (PROMs). Surgery-related complications were recorded.

RESULTS

The distribution of CPAK phenotypes following constitutional aligned TKA was equivalent to the native cohort, whereas the mechanical aligned TKA dramatically altered the phenotype distribution from type I and type II to type V and type IV. Final implant positioning was different between groups, with constitutional aligned TKA having larger cTCA (P = .004), joint line obliquity (P = .006), joint line distance (P = .033) and smaller sFCA (P = .013). Subgroup analysis showed higher actual accuracy of component positioning was achieved in navigated TKA, especially in knees with deformity of > 10° (P < .05). Patients reported higher HSS score at three months postoperatively in constitutional aligned group (P = .002). One patient in navigated group suffered femoral pin site fracture caused by a minor trauma.

CONCLUSION

Computer navigated TKA allows for restoration of constitutional alignment and minimizes soft tissue release, which when compared to mechanical alignment may be associated with superior early outcomes.

Improving alignment in total knee arthroplasty: a cadaveric assessment of a surgical navigation tool with computed tomography imaging

PURPOSE

To investigate the accuracy of an imageless, optical surgical navigation tool to assist with femoral and tibial bone cuts performed during TKA.

PATIENTS AND METHODS

Six board-certified orthopedic surgeons participated in a laboratory cadaver investigation, performing femoral and tibial bone cuts with the assistance of a computer navigation tool. Femoral and tibial varus/valgus, tibial slope, femoral flexion, and both femoral and tibial rotation measurements from the device were compared with angular measurements calculated from computed tomography (CT) images of the knees.

RESULTS

Measurements with the navigation tool were highly correlated with those obtained from CT scans in all three axes. For the distal femoral cut, the absolute mean difference in varus/valgus was 0.83° (SD 0.46°, r = 0.76), femoral flexion was 1.91° (SD 1.16°, r = 0.85), and femoral rotation was 1.29° (SD 1.01°, r = 0.88) relative to Whiteside's line and 0.97° (SD 0.56°, r = 0.81) relative to the posterior condylar axis. For the tibia, the absolute mean difference in varus/valgus was 1.08° (SD 0.64°, r = 0.85), posterior slope was 2.78° (SD 1.40°, r = 0.60), and rotation relative to the anteroposterior axis (posterior cruciate ligament to the medial third of the tibial tuberosity) was 2.98° (SD 2.54°, r = 0.79).

CONCLUSION

Utilization of an imageless navigation tool may aid surgeons in accurately performing and monitoring femoral and tibial bone cuts, and implant rotation in TKA and thus, more accurately align TKA components.

Full-Perception Robotic Surgery Environment with Anti-Occlusion Global-Local Joint Positioning

The robotic surgery environment represents a typical scenario of human-robot cooperation. In such a scenario, individuals, robots, and medical devices move relative to each other, leading to unforeseen mutual occlusion. Traditional methods use binocular OTS to focus on the local surgical site, without considering the integrity of the scene, and the work space is also restricted. To address this challenge, we propose the concept of a fully perception robotic surgery environment and build a global-local joint positioning framework. Furthermore, based on data characteristics, an improved Kalman filter method is proposed to improve positioning accuracy. Finally, drawing from the view margin model, we design a method to evaluate positioning accuracy in a dynamic occlusion environment. The experimental results demonstrate that our method yields better positioning results than classical filtering methods.

Comparing an imageless hand-held robotic-assisted system versus conventional technique for component positioning and early clinical outcomes in total knee arthroplasty

BACKGROUND

This study aimed to examine the component positioning and early clinical outcomes in total knee arthroplasty (TKA) using an imageless hand-held robotic-assisted system compared with those without robotics.

METHODS

Component positioning, hip-knee-ankle angle (HKA), and clinical outcome 1-year postoperatively were compared between 40 patients who underwent TKA with Navio (robot group) and 40 control patients who underwent TKA with a jig-based technique (manual group). The clinical outcomes evaluated were range of motion and the 2011 Knee Society Score.

RESULTS

Implantation errors in the coronal and sagittal alignments were significantly fewer in the robotic group than in the manual group. All knees in the robotic group achieved component positions within 3°. However, the HKA and clinical outcomes did not differ between the groups.

CONCLUSION

Although the accuracy of implantation in the robotic group was superior to that in the manual group, the clinical outcomes were similar.

Does computer-assisted orthopaedics system (ADAPT system) improve outcomes of intertrochanteric hip fractures?

INTRODUCTION

Intramedullary nailing (IMN) is a general treatment for intertrochanteric hip fractures. The computer-assisted orthopaedics system (CAOS), ADAPT system (Stryker, NJ), has been developed to facilitate lag screw insertion. When compared to the conventional freehand method, the efficacy of CAOS has not been clearly clarified. Therefore, we conducted this systematic review and meta-analysis to answer: does the CAOS performed better than freehand method in IMN.

MATERIALS AND METHODS

Studies published up to January 2023 were searched in the PubMed, Embase, Web of Science and Cochrane Library databases with predetermined key words. Comparative clinical studies between CAOS (ADAPT system) and freehand method were included. The primary outcomes of interest were the tip-apex-distance (TAD) and positions of lag screw. Fluoroscopy use, operation duration and intraoperative/postoperative complications were also extracted. A meta-analysis was performed for pooled analysis.

RESULTS

There were seven studies with 326 fractures in CAOS group and 325 fractures in Freehand group. All studies included presented high qualities. The CAOS group showed a statistically smaller TAD than Freehand group (weighted mean difference = -3.24 mm; 95% confidence interval [CI] -5.10 to -1.37 mm; p = 0.0007) and a better lag screw position (83/92 [90.2%] VS 64/92 [69.6%]; RR = 1.3; 95% CI 1.12 to 1.51; p = 0.0007). The operative time and radiation use revealed no difference between two groups.

CONCLUSIONS

The current evidence indicated that ADAPT system could help to perform a more accurate lag screw than freehand manipulation while the operative time and radiation time was not reduced as expectations on such new technique. Long-term follow-up studies are appealed.

The Definition of the Tibial Sagittal Plane and the Paradox of Imageless Navigation and Robotics: A Cadaveric Study

BACKGROUND

The accuracy, precision, and repeatability by which the tibial sagittal plane can be found with imageless technology is currently unknown. The purpose of this study was to identify any differences between imageless and image-based technology to define the sagittal plane of the tibia.

METHODS

A computed tomography (CT) was obtained of 18 cadavers with the knee fully extended. The surgical trans-epicondylar axis and several tibial rotation references were acquired on the CT scan. After a medial parapatellar approach, the same anatomical landmarks were acquired in vivo. In the horizontal plane, the angle between the surgical trans-epicondylar axis and the tibial rotational axes was assessed.

RESULTS

Highest accuracy was found for posterior cruciate ligament (PCL)-anterior cruciate ligament (ACL, -1.48°, standard deviation [SD] 13.64; imageless), tibial medial condyle (TMC)-tibial lateral condyle (TLC, 1.72°, SD 4.24; image-based), the ACL-medial border of tibial tuberosity (MTT, -2.89°, SD 18.86; image-based). Highest precision was acquired with image-based technology: TMC-TLC (SD 4.24), PCL-ACL (SD 5.86), and PCL-medial third of tibial tuberosity (M3TT, SD 7.10). Excellent intraobserver and interobserver correlation coefficients were observed with image-based technology: PCL-MTT, anterior medial condyle (AMC)-anterior lateral condyle (ALC), and TMC-TLC (Intraobserver and interobserver correlation coefficients 0.90-0.98).

CONCLUSION

The tibial sagittal plane could be defined with highest accuracy, precision, and repeatability on a preoperative CT. Imageless methodology lacked the precision and repeatability of image-based technology. With the current pursuit of high accuracy and precision in total knee arthroplasty, the reference frame used to quantify implant position should be highly accurate and precise as well.

LEVEL OF EVIDENCE

IV, Case Series.

Postoperative limb alignment in total knee replacement. Conventional versus navigated versus robotic techniques

BACKGROUND

Our objective was to compare the coronal mechanical axis after total knee replacement (TKR) obtained in three groups of patients subjected to conventional, navigated, and robotic surgery.

METHODS

Retrospective analysis.

RESULTS

124 knees were included (36 conventional, 41 navigated, 47 robotic). No statistically significant differences were found between the postOp tibiofemoral angle of the conventional, navigated and robotic groups (p = 0.396). A repeated-measure analysis of preOp-to-postOp also found no significant differences (p = 0.387). There were no differences in the proportion of outliers (3-degree) found (p = 0.211). Nevertheless, a higher proportion of patients in the robotic group improved their mechanical alignment, as compared with conventional surgery (p = 0.023), although no differences were found when comparing with navigation (p = 0.121).

CONCLUSIONS

No statistically significant differences were found with respect to the postOp alignment achieved. However, statistically significant differences were detected between robotic and conventional surgery when considering the percentage of patients with improved limb alignment.

No Difference in Clinical Outcomes and Survivorship for Robotic, Navigational, and Conventional Primary Total Knee Arthroplasty with a Minimum Follow-up of 10 Years

Background

Computer-assisted surgery, including robotic and navigational total knee arthroplasty (TKA), has been proposed as a technique used to improve alignment of implants. The purpose of this study was to compare the clinical and radiological outcomes during a minimum follow-up period of 10 years among robotic, navigational, and conventional TKA.

Methods

A total of 855 knees (robotic group, 194; conventional group, 270; and navigational group, 391) were available for physical and radiological examinations over a mean follow-up period of 10 years. The survival rate was analyzed using the Kaplan-Meier method based on the survival endpoint. The Hospital for Special Surgery score, Western Ontario and McMaster Universities Osteoarthritis Index, Knee Society Score, and range of motion were used for clinical evaluation. The hip-knee-ankle (HKA) axis angle, the coronal inclination of femoral and tibial components, and the presence of radiolucent lines were also assessed at the final follow-up.

Results

All clinical assessments at the final follow-up revealed improvements in the three groups without any significant difference among the groups (p > 0.05). The cumulative 10-year survival rate was 97.4% in the robotic group, 96.6% in the conventional group, and 98.2% in the navigational group, with no significant difference (p = 0.447). The rates of complication-associated surgery were not significantly different among the groups (p = 0.907). Only the proportion of outliers in the HKA axis angle showed a significant difference (p = 0.001), but other radiological outcomes were not significantly different among the three groups.

Conclusions

Our study demonstrated satisfactory survival rates for robotic, navigational, and conventional TKAs and similar clinical outcomes during the long-term follow-up. Larger studies with continuous serial data are needed to confirm these findings.

A retrospective study of articular surface mounting computer-assisted total knee arthroplasty in alignment, knee function, and survival

Background

Hong Kong Chinese exhibits a greater varus lower limb mechanical axis and coronal bowing when compared to Caucasians. This anatomical difference may affect the accuracy of bone cuts in total knee arthroplasty (TKA) using western anatomy-based intramedullary TKA cutting jigs. Use of computer navigation may avoid suboptimal cuts due to altered anatomy. This is the first study evaluating clinical function, radiological alignment and long-term survival of computer-assisted TKA amongst Hong Kong Chinese patients.

Methods

Retrospective study comparing articular surface mounting computer-assisted TKA (ASM-CATKA) and conventional TKA performed in a single centre from 2008 to 2010. Patients were followed up for ​assessment of clinical parameters including range of motion, Knee Society Knee score, and radiological parameters such as limb alignment, component alignment, and survival.

Results

Seventy-five patients were included in this study. Baseline clinical and radiological data were similar between groups. The computer-navigated group had superior radiological mechanical alignment ( p < 0.001), tibial component alignment ( p = 0.016) and femoral component alignment ( p < 0.01) when compared to conventional TKA. There were no differences in knee scores ( p = 0.488), range of motion ( p = 0.432) and survival at 117 months ( p = 0.986) between the two groups.

Conclusion

This retrospective study showed that ASM-CATKA was more accurate in achieving neutral mechanical axis and component alignment amongst Hong Kong Chinese. Clinical outcomes and implant survival were comparable.

The learning curve associated with imageless navigation in total knee arthroplasty

INTRODUCTION

Computer-assisted navigation systems (CAS) are increasingly being integrated into total knee arthroplasty (TKA) procedures, but perceptions of associated learning curve and increased operative time continue to curtail uptake. Newer-generation navigational systems aim to streamline integration into surgical workflow to mitigate increases in operative time. Here, we assess the impact of a novel imageless CAS on operative time for TKA.

METHODS

A retrospective analysis of prospectively collected data of a cohort of patients undergoing primary unilateral TKA with one of three surgeons between October 2019 and March 2020 was conducted. Consecutive cases using a novel imageless CAS were included in analysis. For each surgeon, average operative time was recorded and compared in sequential five-case cohorts to average operative time for the same procedure performed conventionally using a two-tailed t test.

RESULTS

Average conventional operative times were 95.9 ± 15.0, 86.6 ± 13.7, and 116.9 ± 25.1 min for the three surgeons. Initial CAS-assisted operative times increased to 107.0 ± 9.8 (p = 0.07) and 102.4 ± 13.2 (p = 0.06) min for Surgeons 1 and 2 and decreased to 113.2 ± 9.8 min (p = 0.52) for Surgeon 3. Most recent CAS-assisted operative times were 94.8 ± 13.9 (p = 0.88), 88.7 ± 15.3 (p = 0.84), and 104.8 ± 13.2 (p = 0.12) min as compared to pre-CAS. Absolute differences for the most recent navigated procedures ranged from 12.1 min faster to 2.0 min slower.

CONCLUSION

The learning curve for TKA navigation may be as few as 10 cases, and any associated increases in operative time may be transient and non-significant. Moreover, navigation may ultimately speed operative time, perhaps as the result of enhanced intraoperative assessment of alignment.

No Difference in Quality-Of-Life Outcomes in the First 7 Years Following Primary Total Knee Arthroplasty Performed Using Computer Navigation Versus Conventional Referencing: A Propensity Score-Matched Analysis

BACKGROUND

Computer navigation techniques can potentially improve both the accuracy and precision of prosthesis implantation in total knee arthroplasty (TKA) but its impact on quality-of-life outcomes following surgery remains unestablished.

METHODS

An institutional arthroplasty registry was queried to identify patients with TKA performed between January 1, 2007 and December 31, 2019. Propensity score matching based on demographical, medical, and surgical variables was used to match computer-navigated to conventionally referenced cases. The primary outcomes were Veterans RAND 12 Item Health Survey scores (VR-12 PCS and MCS), Short Form 6 Dimension utility values (SF-6D), and quality-adjusted life years (QALYs) in the first 7 years following surgery.

RESULTS

A total of 629 computer-navigated TKAs were successfully matched to 1,351 conventional TKAs. The VR-12 PCS improved by a mean of 12.75 and 11.94 points in computer-navigated and conventional cases at 12-month follow-up (P = .25) and the VR-12 MCS by 6.91 and 5.93 points (P = .25), respectively. The mean VR-12 PCS improvement at 7-year follow-up (34.4% of the original matched cohort) for navigated and conventional cases was 13.00 and 12.92 points (P = .96) and for the VR-12 MCS was 4.83 and 6.30 points (P = .47), respectively. The mean improvement in the SF-6D utility score was 0.164 and 0.149 points at 12 months (P = .11) and at 7 years was 0.115 and 0.123 points (P = .69), respectively. Computer-navigated cases accumulated 0.809 QALYs in the first 7 years, compared to 0.875 QALYs in conventionally referenced cases (P = .65). There were no differences in these outcomes among a subgroup analysis of obese patients (body mass index ≥ 30 kg/m²).

CONCLUSION

The use of computer navigation did not provide an incremental benefit to quality-of-life outcomes at a mean of 2.9 years following primary TKA performed for osteoarthritis when compared to conventional referencing techniques.

Computer-assisted surgery and patient-specific instrumentation improve the accuracy of tibial baseplate rotation in total knee arthroplasty compared to conventional instrumentation: a systematic review and meta-analysis

PURPOSE

To determine whether patient-specific instrumentation (PSI), computer-assisted surgery (CAS) or robot-assisted surgery (RAS) enable more accurate rotational alignment of the tibial baseplate in primary total knee arthroplasty (TKA) compared to conventional instrumentation, in terms of deviation from the planned target and the proportion of outliers from the target zone.

METHODS

The authors independently conducted three structured electronic literature searches using the PubMed, Embase®, and Cochrane Central Register of Controlled Trials databases from 2007 to 2020. Studies were included if they compared rotational alignment of the tibial baseplate during TKA using conventional instrumentation versus PSI, CAS, and/or RAS, and reported deviation from preoperatively planned rotational alignment of the tibial baseplate in terms of absolute angles and/or number of outliers. Methodological quality of eligible studies was assessed by two researchers according to the Downs and Black Quality Checklist for Health Care Intervention Studies.

RESULTS

Fifteen studies, that reported on 2925 knees, were eligible for this systematic review, of which 6 studies used PSI, and 9 used CAS. No studies were found for RAS. Of the studies that reported on angular deviation from preoperatively planned rotational alignment, most found smaller deviations using PSI (0.5° to 1.4°) compared to conventional instrumentation (1.0° to 1.6°). All studies that reported on proportions of outliers from a target zone (± 3°), found lower rates of outliers using PSI (0 to 22%) compared to conventional instrumentation (5 to 96%). Most studies reported smaller angular deviation from preoperatively planned rotational alignment using CAS (0.1° to 6.9°) compared to conventional instrumentation (1.1° to 7.8°). Of the studies that reported on proportions of outliers from a target zone (± 3°), most found fewer outliers using CAS (10 to 61%) compared to conventional instrumentation (17 to 78%).

CONCLUSION

This systematic review and meta-analysis revealed that both CAS and PSI can improve the accuracy of rotational alignment of the tibial baseplate by decreasing angular deviation from the preoperatively planned target and reducing the proportion of outliers from the target zone. The clinical relevance is that PSI and CAS can improve alignment, though the thresholds necessary to grant better outcomes and survival remain unclear.

LEVEL OF EVIDENCE

IV.

Imageless Computer Navigation Reduces 5-Year All-Cause Revision Rates After Primary Total Knee Arthroplasty

BACKGROUND

The use of surgical navigation has been shown to reduce revision rates after total knee arthroplasty (TKA) in patients <65 years of age. It is unknown if this benefit extends to older patients. We hypothesized that the use of surgical navigation would reduce rates of all-cause revision in patients of all ages.

METHODS

In this cohort study, we queried the Truven MarketScan all-payer database to identify patients who underwent TKA from 2007 to 2015. Current Procedural Terminology codes were used to create 2 groups based on whether intraoperative navigation was used. Demographics, comorbidities, complications, and revision rates were determined. International Classification of Diseases codes were used to determine reasons for revision.

RESULTS

The conventional TKA cohort included 312,173 patients. The navigation cohort included 20,881 patients. There were not any clinically significant differences in demographics between the cohorts. All-cause revision rates were lower in the navigation cohort at 1 year (0.4% vs 0.5%, P = .04), 2 years (0.7% vs 0.9%, P = .003), and 5 years (0.9% vs 1.3%, P < .001) of follow-up. Revisions for mechanical loosening were more common in the conventional cohort (30.8% vs 21.9%, P = .009). Rates of revision for other causes, including infection, did not differ between groups, with the numbers available.

CONCLUSION

The use of surgical navigation yielded a 30.7% reduction in the all-cause revision rate at 5-year follow-up compared to conventional TKA. This benefit increased as follow-up duration increased. Increased usage of this inexpensive technology, from the current 6.3% in this US cohort, may reduce healthcare costs.

LEVEL OF EVIDENCE

III.

Avoidance of intramedullary violation in computer-assisted total knee arthroplasty lowers the incidence of periprosthetic joint infection compared with conventional total knee arthroplasty: A propensity score matching analysis of 5342 cases

BACKGROUND

Conventional total knee arthroplasty (CONV-TKA) inevitably perturbs femoral medullary canal, disturbs medullary micro-architecture and increases blood loss and inflammatory responses. We hypothesized that avoidance of intramedullary violation may lower the incidence of periprosthetic joint infection (PJI). The aim of this study was to verify whether computer-assisted total knee arthroplasty (CAS-TKA) lowers the incidence of PJI as compared with CONV-TKA.

METHODS

A propensity score matching study of 5342 patients who underwent CAS-TKA (n = 1085) or CONV-TKA (n = 4257) for primary osteoarthritis of the knee from 2007 to 2015 in our institute was performed. Patients who underwent CAS-TKA were matched to those who received CONV-TKA at a 1:2 ratio according to demographics and comorbidities. PJI was defined according to the Musculoskeletal Infection Society diagnostic criteria from the 2013 International Consensus Meeting.

RESULTS

After controlling potential risk factors, the use of CAS-TKA resulted in a lower incidence of PJI as compared with CONV-TKA [adjusted hazard ratio (HR), 0.42; 95% confidence interval (CI), 0.18-0.99]. The same trend in PJI reduction was observed with the usage of CAS-TKA under sensitivity testing [HR, 0.33; 95% CI, 0.12-0.95]. The cumulative incidence of PJI was lower in the CAS-TKA group than the CONV-TKA group (log-rank test, p = 0.013).

CONCLUSION

Avoidance of intramedullary violation during TKA may play a pivotal role in lowering the incidence of PJI. The use of CAS-TKA can reduce the incidence of PJI, with a better survival rate in terms of being free of PJI, as compared with CONV-TKA.

Improved joint awareness two years after total knee arthroplasty with a handheld image-free robotic system

Literature into the short-term follow-up of total knee arthroplasty (TKA) using a handheld image- free robotic system are scarce. The purpose of this study was to compare the clinical outcomes and patient-reported outcome measures (PROMs) between patients operated for TKA with an image- free robotic system (robot group) or conventionally TKA (conventional group) 2 years postoperatively. A total of 147 patients were evaluated after TKA, respectively 73 in the robot and 74 in conventional group. Outcome measures included adverse events (AEs), hospital readmission rate, patient satisfaction and the following PROMs: Pain Visual Analogue Score (VAS), Oxford Knee Score (OKS), Forgotten Joint Score Knee (FJS-12) and the EuroQOL-5D (EQ-5D). There were no statistically significant differences in the number of AEs; 8 (10.8%) in the conventional group versus 7 (9.7%) in the robot group. The FJS (p ≤ 0.05) and OKS (p ≤ 0.05) differed statistically in favour of the robot group. The EQ-5D and EQ-5D VAS did not statistically differed between the groups (p=0.231 and p=0.373 respectively). The VAS pain improved statically significant in both groups when comparing the pre- and postoperative values (5.8 points). Patients operated with a handheld image-free robotic system have the ability to forget their artificial knee joint in everyday life as measured with the FJS-12 at short-term follow-up.

No difference in long-term functional outcomes or survivorship after total knee arthroplasty with or without computer navigation: a 17-year survivorship analysis

Background

The literature comparing the long-term outcomes and survivorship of computer navigation-assisted and conventional total knee replacement (TKR) is sparse. Moreover, of the available comparative studies with follow-up duration of more than 10 years, the results seem to be conflicting. The purpose of this long-term study was to compare the clinical and radiological outcomes, and implant survivorship, of TKR performed with and without computer navigation.

Methods

We retrospectively compared the results of 49 computer-navigated TKRs and 139 conventional TKRs. The mean age of the patients was 67.9 (range 52–81) years for the navigation group and 67.1 (range 50–80) years for the conventional TKR group. The mean duration of follow-up for the conventional and navigation TKR groups was 12.9 and 13.2 years, respectively. Clinical and radiographic follow-up examinations of the patients were performed at 2 weeks, 1 month, 3 months and 6 months post-operatively, and at 1-year intervals thereafter.

Results

There were no significant differences in the post-operative Knee Society knee and function score between the two groups. The mean overall deviation from neutral alignment and the radiological outliers were significantly higher in the conventional TKR group. The overall survival rates at 17 years were 92.9% for the navigation group and 95.6% for the conventional TKR group (p = 0.62).

Conclusions

Navigated TKR resulted in fewer radiological outliers; however, this did not translate to better long-term functional outcomes or implant survival.

No influence of obesity on mid-term clinical, functional, and radiological results after computer-navigated total knee arthroplasty using a gap balancing technique

OBJECTIVE

In obese patients, thick subcutaneous tissue can introduce errors during registration and leg weight can influence gap balancing in navigated TKA. Present study is done to determine if computer navigated TKA using a gap balancing technique can achieve consistent accuracy for limb and component alignment, and similar clinical and functional results in obese patients like in non-obese patients.

METHODS

We prospectively compared the radiological, clinical, and functional results of 78 knees in 57 non-obese patients and 79 knees in 58 obese patients who underwent computer-assisted TKA. Non-obese individuals were defined as those having BMI of <30 kg/m² and obese individuals as BMI ≥30 kg/m². The degree of knee deformity was calculated by Hip - Knee - Ankle (HKA) angle and clinical and functional assessment was done using the Knee Society Score - clinical knee score and Knee Society Score - function score, respectively. All these were documented before and at 6 months, 2 year, and 5 years after TKA.

RESULTS

The outlier rate of postoperative limb alignment (HKA angle) was 8.9% in the obese group which was not significantly different (p =1.00) from that of the non-obese group (7.7%). Mean clinical knee scores were not significantly different between the non-obese and obese groups preoperatively (58.8 vs 57.4, p = 0.14) and at 6 months (92.7 vs 91, p = 0.06), 2 years (91.4 vs 90, p = 0.07), and 5 years (92.4 vs 91.3, p = 0.1) post-surgery. Similarly, mean functional scores were not significantly different between the non-obese and obese groups preoperatively (50.9 vs 49.9, p = 0.31) and at 6 months (92.7 vs 90.9, p = 0.06), 2 years (91.3 vs 92, p = 0.44), and 5 years (90.6 vs 91.1, p = 0.51) post-surgery.

CONCLUSION

Obesity has no influence on mid-term clinical, functional, and radiological results after computer navigated TKA, done by gap balancing technique.

LEVEL OF EVIDENCE

Therapeutic level II.

Pros and cons of navigated versus conventional total knee arthroplasty-a retrospective analysis of over 2400 patients

INTRODUCTION

Because of the ongoing discussion of imageless navigation in total knee arthroplasty (TKA), its advantages and disadvantages were evaluated in a large patient cohort.

METHODS

This retrospective analysis included 2464 patients who had undergone TKA at a high-volume university arthroplasty center between 2012 and 2017. Navigated and conventional TKA were compared regarding postoperative mechanical axis, surgery duration, complication rates, one-year postoperative patient-reported outcome measures (PROMs) (WOMAC and EQ-5D indices), and responder rates as defined by the criteria of the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus (OMERACT-OARSI).

RESULTS

Both navigated (1.8 ± 1.6°) and conventional TKA (2.1 ± 1.6°, p = 0.002) enabled the exact reconstruction of mechanical axis. Surgery duration was six minutes longer for navigated TKA than for conventional TKA (p < 0.001). Complication rates were low in both groups with comparable frequencies: neurological deficits (p = 0.39), joint infection (p = 0.42 and thromboembolic events (p = 0.03). Periprosthetic fractures occurred more frequently during conventional TKA (p = 0.001). One-year PROMs showed excellent improvement in both groups. The WOMAC index was statistically higher for navigated TKA than for conventional TKA (74.7 ± 19.0 vs. 71.7 ± 20.7, p = 0.014), but the increase was not clinically relevant. Both groups had a similarly high EQ-5D index (0.23 ± 0.24 vs. 0.26 ± 0.25, p = 0.11) and responder rate (86.5% [256/296] vs. 85.9% [981/1142], p = 0.92).

CONCLUSION

Both methods enable accurate postoperative leg alignment with low complication rates and equally successful PROMs and responder rates one year postoperatively.

LEVEL OF EVIDENCE

III. Retrospective cohort study.

Comparison of the clinical effects of computer-assisted and traditional techniques in bilateral total knee arthroplasty: A meta-analysis of randomized controlled trials

Background

It is unclear whether there are individual differences in the long-term efficacy of computer-assisted and traditional total knee arthroplasty. The purpose of this study was to perform a meta-analysis comparing the same individuals undergoing computer-assisted and traditional total knee arthroplasty separately to determine whether computer-assisted total knee arthroplasty can provide better lower extremity radiographic results and clinical outcomes.

Methods

We searched literatures to identify relevant randomized controlled trials comparing the effects of computer-assisted and traditional methods in bilateral total knee arthroplasty. After screening, quality evaluation and data extraction according to inclusion and exclusion criteria, the quality and bias risks of the included studies were evaluated. The meta-analysis compared the radiographic results, functional outcomes and complications of the two techniques.

Results

Six clinical controlled trials were included, with total of 1098 patients. The meta-analysis showed that the accuracy in terms of the mechanical axis of the lower extremity, the sagittal alignment of the femoral component and the coronal alignment of the tibial component in computer-assisted total knee arthroplasty was significantly better than those in traditional total knee arthroplasty. There were no differences in the functional results, revision rates or aseptic loosening rates between the two techniques.

Conclusion

After excluding individual differences such as bone development and bone quality, although computer-assisted techniques can better accurately correct the mechanical axis of the lower extremity and the position of prosthesis implantation than traditional techniques, there is no significant difference in the functional results and revision rate of bilateral total knee arthroplasty in the same individual.

Computerized Navigation: A Useful Tool in Total Knee Replacement

The purpose of computer assistance in a total knee replacement is to achieve optimal alignment, size, and positioning of the implant. The method is safe and accurate and may be particularly useful in cases with abnormal anatomy.

Clinical use of computer-assisted orthopedic surgery in horses

OBJECTIVE

To describe clinical applications of computer-assisted orthopedic surgery (CAOS) in horses with a navigation system coupled with a cone beam computed tomography unit.

STUDY DESIGN

Retrospective clinical case series.

ANIMALS

Thirteen adult horses surgically treated with CAOS.

METHODS

Medical records were searched for horses that underwent CAOS between 2016 and 2019. Data retrieved included signalment, diagnosis, lameness grade prior to surgery, surgical technique and complications, anesthesia and surgery time, and information pertaining to the perioperative case management and outcome.

RESULTS

In 10 cases, surgical implants were placed in the proximal phalanx, third metatarsal bone, ulna, or medial femoral condyle. In one case, navigated transarticular drilling was performed to promote ankylosis of the distal tarsal joints. In another case, an articular fragment of the middle phalanx was removed with the help of CAOS guidance. In the final case, a focal osteolytic lesion of the calcaneal tuber was curetted with the aid of CAOS. In seven cases, a purpose-built frame was used for the surgical procedure. All surgeries were performed successfully and according to the preoperative plan.

CONCLUSION

Computer-assisted orthopedic surgery can be an integral part of the clinical case management in equine surgery. To optimize workflow and time-efficiency, the authors recommend designating one team for operative planning and another for the execution of the surgical plan. Specialized equipment, such as the purpose-built frame, will further improve CAOS applications in equine surgery.

CLINICAL SIGNIFICANCE

After they have become familiar with the operational principles, equine surgeons can readily apply CAOS for a broad spectrum of indications.

A prospective randomized study comparing navigation versus conventional total knee arthroplasty

BACKGROUND

Navigation is associated with improved accuracy in alignment. However, its influence on clinical outcome is inconclusive. The aim of this study was to compare the component alignment and functional outcome in patients undergoing navigation-assisted and conventional total knee replacement (TKR).

MATERIALS AND METHOD

A prospective randomized study consisting of two groups (group A and group B) was carried out. Group A consisted of patients undergoing TKR using conventional jig-based method, whereas group B consisted of patients undergoing TKR using computer navigation-assisted method. We measured and compared the coronal and sagittal plane alignment in X-ray and rotational alignment in computed tomography scan between both groups. Functional outcome was analysed using Knee Society Score (KSS) and Western Ontario and McMaster University scale (WOMAC) score.

RESULTS

A total of 50 patients were randomized into two groups A and B each with 25 patients. Navigation was associated with more accuracy in mechanical axis alignment ( p = 0.011) and femoral component rotation ( p = 0.033). The mean follow-up was 4.6 years (range 48-62 months). There was no statistically significant difference between the groups with respect to KSS and WOMAC score at the minimum follow-up of 4 years.

CONCLUSION

We concluded that even though navigation-assisted system is associated with better accuracy, there was no difference in clinical outcome at an average follow-up of 4.6 years.

Is TKA with computer-assisted navigation associated with less blood loss? A comparative study between computer-navigated and conventional method

The aim of this study is to evaluate whether computer-assisted navigated TKA reduces perioperative blood loss. Patients were randomly divided into 2 groups and underwent either a conventional TKA (n = 40) or a TKA with computer-assisted navigation (n = 40). Perioperative blood loss was evaluated by laboratory parameters, postoperative drain output and number of required transfusions. Change in hemoglobin concentration and in hematocrit levels was similar. Also, there was no statistically significant difference in drain output and in the number of transfused units. The results of this study showed that TKA with computer-assisted navigation is similar to the conventional TKA regarding perioperative hemorrhage.

An umbrella review comparing computer-assisted and conventional total joint arthroplasty: quality assessment and summary of evidence

Background

Systematic reviews (SRs) of computer-assisted (CA) total knee arthroplasty (TKA) and total hip arthroplasty (THA) report conflicting evidence on its superiority over conventional surgery. Little is known about the quality of these SRs; variability in their methodological quality may be a contributing factor. We evaluated the methodological quality of all published SRs to date, summarized and examined the consistency of the evidence generated by these SRs.

Methods

We searched four databases through December 31, 2018. A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2) was applied to assess the methodological quality. Evidence from included meta-analyses on functional, radiological and patient-safety outcomes was summarized. The corrected covered area was calculated to assess the overlap between SRs in including the primary studies.

Results

Based on AMSTAR 2, confidence was critically low in 39 of the 42 included SRs and low in 3 SRs. Low rating was mainly due to failure in developing a review protocol (90.5%); providing a list of excluded studies (81%); accounting for risk of bias when discussing the results (67%); using a comprehensive search strategy (50%); and investigating publication bias (50%). Despite inconsistency between SR findings comparing functional, radiological and patient safety outcomes for CA and conventional procedures, most TKA meta-analyses favored CA TKA, whereas most THA meta-analyses showed no difference. Moderate overlap was observed among TKA SRs and high overlap among THA SRs.

Conclusions

Despite conclusions of meta-analyses favoring CA arthroplasty, decision makers adopting this technology should be aware of the low confidence in the results of the included SRs. To improve confidence in future SRs, journals should consider using a methodological assessment tool to evaluate the SRs prior to making a publication decision.

3D imaging and stealth navigation instead of CT guidance for radiofrequency ablation of osteoid osteomas: a series of 52 patients

Background

Osteoid osteomas are benign bone neoplasms that may cause severe pain and limit function. They are commonly treated by radiofrequency ablation (RFA) through a needle inserted into the nidus of the lesion under CT guidance, which is associated with exposure of young patients to relatively high dose of radiation. The objective of this study was to investigate the amount of radiation, effectiveness and safety of an alternative imaging approach, the 3D image-guided (O-arm) technology and the Stealth navigation.

Methods

We retrospectively reviewed 52 electronic medical files of patients (mean age 24.7 years, range 8–59 years) who were treated with thermal ablation of benign osteoid osteomas guided by the navigated O-arm-assisted technique in our institution between 2015 and 2017. Data were extracted on the associated complications, the reduction in pain at 3 months and one year postoperatively, and the amount of radiation administered during the procedure.

Results

The level of pain on a visual analogue scale decreased from the preoperative average of 7.73 to 0 at the 3-month follow-up. The mean dose-length product was 544.7 mGycm² compared to the reported radiation exposure of 1971–7946 mGycm² of CT-guided radio ablations. The one intra-operative complication was a superficial burn in the subcutaneous lesion in a tibia that was treated locally with no major influence on recovery.

Conclusions

RFA ablation guided by 3D O-arm stealth navigation is as effective as the traditional CT-guided technique with the advantage of lower radiation exposure.

Trial registration

Retrospective study number 0388–17-TLV at Tel Aviv Sourasky Medical Center IRB, approved at 25.10.17.

Comparison of iASSIST Navigation System with Conventional Techniques in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of Radiographic and Clinical Outcomes

The iASSIST navigation system is a handheld accelerometer‐based navigation system that has been applied in clinical practice in recent five years. This meta‐analysis aimed to compare the radiographic and clinical outcomes of iASSIST navigation with conventional surgical techniques for patients undergoing total knee arthroplasty (TKA) and to compare the surgery time between an iASSIST group and a conventional treatment group. This systematic review and meta‐analysis included all comparative prospective and retrospective studies published in Pubmed, Embase, the Cochrane Central Register of Controlled Trials, the Web of Science and the CNKI databases over the past 20 years. Inclusion criteria were studies that compared the iASSIST navigation system with conventional TKA. The primary outcomes were mechanical axis (MA) and outliers, which means postoperative MA varus or valgus of more than 3°. Secondary outcomes were coronal femoral angle (CFA) and coronal tibial angle (CTA). Knee Society Score (KSS) was used to evaluate functional outcome. The Newcastle–Ottawa Scale (NOS) was used to assess the methodological quality of included studies. Eight studies involving 558 knees were included in this meta‐analysis. Of these, 275 patients used the iASSIST navigation system and 283 used conventional surgical techniques. A total of 5 studies were considered high quality and the other 3 were considered to be of moderate quality. The occurrence of malalignment of >3° in the iASSIST group was 13.3%, compared with 29.04% in the conventional group. Postoperative MA of the iASSIST group was significantly better than that of the conventional group (I² = 19%, OR = −0.92, 95% CI = −1.09 to −0.75, P < 0.00001). The iASSIST navigation system provided significantly increased accuracy in the coronal femoral angle (I² = 79%, OR = −0.88, 95% CI = −1.21 to −0.54, P < 0.00001) and the coronal tibial angle (I² = 34%, OR = 0.39, 95% CI = −0.48 to −0.30, P < 0.00001) compared with conventional techniques. However, the duration of surgery using the iASSIST procedure was longer and there was no significant difference in the short‐term KSS in the iASSIST group compared with the conventional group. We found that when pooling the data of included studies, the number of outliers was fewer in the iASSIST group, and compared with conventional TKA techniques, the iASSIST system significantly improved the accuracy of lower limb alignment but the duration of surgery was prolonged in addition to there being no apparent advantage in terms of short‐term functional score.

Optimal Design of Patient-Specific Total Knee Arthroplasty for Improvement in Wear Performance

Life expectancy is on the rise and, concurrently, the demand for total knee arthroplasty (TKA), which lasts a lifetime, is increasing. To meet this demand, improved TKA designs have been introduced. Recent advances in radiography and manufacturing techniques have enabled the production of patient-specific TKA. Nevertheless, concerns regarding the wear performance, which limit the lifespan of TKA, remain to be addressed. This study aims at reducing the wear in patient-specific TKA using design optimization and parametric three-dimensional (3D) finite-element (FE) modelling. The femoral component design was implemented in a patient-specific manner, whereas the tibial insert conformity remained to be determined by design variables. The gait cycle loading condition was applied, and the optimized model was validated by the results obtained from the experimental wear tests. The wear predictions were iterated for five million gait cycles using the computational model with force-controlled input. Similar patterns for internal/external rotation and anterior/posterior translation were observed in both initial and optimal models. The wear rates for initial and optimal models were recorded as 23.2 mm³/million cycles and 16.7 mm³/million cycles, respectively. Moreover, the experimental wear rate in the optimal design was 17.8 mm³/million cycles, which validated our optimization procedure. This study suggests that tibial insert conformity is an important factor in influencing the wear performance of patient-specific TKA, and it is capable of providing improved clinical results through enhanced design selections. This finding can boost the future development of patient-specific TKA, and it can be extended to other joint-replacement designs. However, further research is required to explore the potential clinical benefits of the improved wear performance demonstrated in this study.

Accelerometer-Based Navigation in Total Knee Arthroplasty for the Management of Extra-Articular Deformity and Retained Femoral Hardware: Analysis of Component Alignment

Purpose  Recent advances in total knee arthroplasty (TKA) include an accelerometer portable system designed to improve component position and alignment. The purpose of this study is to evaluate whether accelerometer navigation system can be a valuable option in complex TKAs for extra-articular deformity of the lower limb or in case of retained femoral hardware. Methods  A group of 13 patients underwent TKA with an accelerometer navigation system. Three patients had a tibial extra-articular deformity, six had a femoral extra-articular deformity, and four had an intramedullary nail in the femur. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. The alignment of prosthetic components in the frontal and sagittal planes was determined by postoperative radiographs. Results  At 30-days postoperative radiographic check, the hip knee ankle angle was within 2.0° (0 ± 1) of the neutral mechanical axis. The alignment of the tibial component on the frontal plane was 90.0° (range 89-91) and on the sagittal plane 5.0° (range 3-7). The alignment of the femoral component on the frontal plane was 90.0° (range 89-91) and on the sagittal plane 3.0° (range 0-5). Conclusion  The alignment of the prosthetic components has been accurate and comparable to other navigation systems in literature without any increase in surgical times. The accelerometer-based navigation system is therefore a useful technique that can be used to optimize TKA alignment in patients with extra-articular deformity or with lower limb hardware, where the intramedullary guides cannot be applied. Level of Evidence  This is an observational study without a control group, Level III.

Does navigated patellar resurfacing in total knee arthroplasty result in proper bone cut, motion and clinical outcomes?

BACKGROUND

In total knee arthroplasty with patellar resurfacing, patellar bone preparation, component positioning and motion assessments are still not navigated. Only femoral/tibial component positioning is supported by computer-assistance. The aim of this study was to verify, in-vivo, whether knee surgical navigation extended to patellar resurfacing, by original instrumentation and procedures for patellar-based tracking, could achieve accurate patella preparation in terms of original thickness restoration, bone cut orientation, and normal knee motion.

METHODS

An additional navigation system for patellar data acquisition was used together with a standard navigation system for total knee arthroplasty in 20 patients. This supported the surgeon for patellar resurfacing via measurement of removed bone thickness, three-dimensional patellar cut orientations, and patello-femoral motion. Radiological and clinical examinations at 6 and 24-month follow-up were also performed.

FINDINGS

The medio-lateral patellar-bone cut orientation was respectively 0.5° (standard deviation: 3.0°) and 1.4° (1.7°) lateral tilt, as measured via navigation and post-operatively on the Merchant x-ray view. The cranio-caudal orientation was 3.8° (7.2°) of flexion. The thickness variation between patellar pre- and post-implantation was 0.2 (1.3) mm. Immediately after implantation, patello-femoral as well as tibio-femoral kinematics was within the normality. Good radiological and clinical examinations at 6 and 24-month follow-up were also observed.

INTERPRETATION

For the first time, the effect of patellar navigation for its resurfacing was assessed in-vivo during surgery, with very good results for thickness restoration, proper cut orientation, and normal knee motion. These results support the introduction of patella-related navigation-based surgical procedures for computer-assisted total knee arthroplasty.

Intraoperative validation of bone cut accuracy of a pinless smart touch-screen navigation system device in total knee arthroplasty

PURPOSE

Primary objective in most of the published literature on computer-assisted total knee arthroplasty (TKA) has so far been the comparison of axial alignment and components position, obtained either through navigation systems or through conventional instrumentation. We have found no studies aimed at assessing the intraoperative reliability of a navigation system in relation to bone cuts height. Aim of our study was therefore to establish bone cut accuracy of a pinless navigation system.

METHODS

From January 2014 to February 2016, 44 consecutive patients requiring total knee replacement (TKR) were enrolled in a prospective study. Primary end point of the study was to assess the accuracy of the DASH iPOD TOUCH Navigation System (Brainlab AG, Feldkirchen, Germany) by measuring the real thickness of both tibial and femoral osteotomies. We compared the data indicated by the navigation system with the intraoperative anatomical measurements done with the aid of a caliper. In addition, the radiographic alignment was compared with the data derived from the navigator.

RESULTS

The device proved to be precise. Differences between the two methods of measurement are distributed over a millimeter range. Radiological measurements showed that 95.5% of tibial components were within the range of 3° varus/valgus; same results were obtained by the navigation system; instead, 90.1% of femoral components were within the range of 3° varus/valgus based on the radiological measurement, whereas according to the navigation system, 86.4% were in this range.

CONCLUSIONS

The DASH iPOD TOUCH Navigation System is a precise and reliable instrument to assist in TKA navigation.

Patient-Specific Instrumentation Does Not Affect Rotational Alignment of the Femoral Component and Perioperative Blood Loss in Total Knee Arthroplasty: A Prospective, Randomized, Controlled Trial

BACKGROUND

Proposed aims of patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) are to improve accuracy of component alignment, while reducing blood loss and surgical time. The primary goal of this prospective, randomized, controlled, clinical trial is to verify whether PSI improves the rotational alignment of the femoral component in comparison to conventionally implanted TKA.

METHODS

One-hundred thirty-three consecutive patients were assessed for eligibility. Block randomization was performed to allocated patients in the treatment (PSI) or control group. During hospital stay, surgical times were recorded, and total blood volume loss and estimated red blood cell were calculated. Two months after surgery, a computed tomography of the knee was obtained to measure femoral component rotation to the transepicondylar axis and tibial component slope.

RESULTS

Sixty-nine patients were enrolled. PSI did neither result in a significant improvement in femoral component rotation nor result in a reduction of outliers, as compared with conventional instrumentation. No significant improvement in terms of tibial slope, blood loss, total surgical time, and ischemia time could be identified. The number of tibial recuts required in the PSI group was significantly higher than in the control group (P = .0003).

CONCLUSION

PSI does not improve the accuracy of femoral component rotation in TKA in comparison to conventional instrumentation. Moreover, PSI did not appear to influence any of the other variables investigated as secondary goals by this study. The results of this study do not support its routine use during standard TKA.

LEVEL OF EVIDENCE

Level I, randomized, controlled trial.

Trends in computer navigation and robotic assistance for total knee arthroplasty in the United States: an analysis of patient and hospital factors

Background

Computer navigation and robotic assistance technologies are used to improve the accuracy of component positioning in total knee arthroplasty (TKA), with the goal of improving function and optimizing implant longevity. The purpose of this study was to analyze trends in the use of technology-assisted TKA, identify factors associated with the use of these technologies, and describe potential drivers of cost.

Methods

The Nationwide Inpatient Sample database was used to identify patients who underwent TKA using conventional instrumentation, computer navigation, and robot-assisted techniques between 2005 and 2014. Variables analyzed include patient demographics, hospital and payer types, and hospital charges. Descriptive statistics were used to describe trends. Univariate and multivariate analyses were performed to identify differences between conventional and technology-assisted groups.

Results

Our analysis identified 6,060,901 patients who underwent TKA from 2005 to 2014, of which 273,922 (4.5%) used computer navigation and 24,084 (0.4%) used robotic assistance. The proportion of technology-assisted TKAs steadily increased over the study period, from 1.2% in 2005 to 7.0% in 2014. Computer navigation increased in use from 1.2% in 2005 to 6.3% in 2014. Computer navigation was more likely to be used in the Western United States, whereas robot-assisted TKAs were more likely to be performed in the Northeast. Increased hospital charges were associated with the use of technology assistance ($53,740.1 vs $47,639.2).

Conclusions

The use of computer navigation and robot-assisted TKA steadily increased over the study period, accounting for 7.0% of TKAs performed in the United States in 2014. Marked regional differences in the use of these technologies were identified. The use of these technologies was associated with increased hospital charges.

An innovative three-dimensional method for identifying a proper femoral intramedullary entry point in total knee arthroplasty

Background:

Identification of the proper femoral intramedullary (IM) access point is an important determinant of final implant position in IM-guided total knee arthroplasty (TKA). The aim of this study was to identify the optimal entry point in Chinese participants using a new three-dimensional method.

Methods:

A series of computed tomography scans of 44 femurs in Chinese participants from October 2014 to October 2015 were imported into Mimics 17.0 software to identify the optimal entry point. The apex of the intercondylar notch (AIN) was used as the reference bony anatomical landmark to identify the proper entry point to insert the IM rod. The statistical significance was calculated on the basis of a 5% level (P < 0.05) using the Student's t-test.

Results:

For the males, the average ideal entry point was 1.49 mm medial and 13.39 mm anterior to the AIN. The values were 1.77 mm medial and 15.29 mm anterior to the AIN in females. A significant difference was present between males and females (13.39 ± 2.46 mm vs. 15.29 ± 3.44 mm, t = 2.124, P = 0.040). When using the recommended location as the entry point for the IM rod, the mean potential error differed significantly from the femoral trochlear groove (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.27° ± 0.32°, t = −4.166, P < 0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.79° ± 0.70°, t = −7.155, P < 0.001; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.15° ± 0.35°, t = −3.940, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.76° ± 0.83°, t = −5.574, P < 0.001). A significant difference was present between the recommended point and the point 10 mm anterior to the origin of the posterior cruciate ligament (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.53° ± 0.43°, t = −5.948, P < 0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.15° ± 0.75°, t = −3.152, P = 0.003; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.28° ± 0.42°, t = −4.632, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.40° ± 0.93°, t = −3.763, P = 0.001).

Conclusions:

The technique described here is an innovative method for swift, easy, and accurate access to the medullary canal during TKA, and it can optimize the position and orientation of the prosthetic components in knee arthroplasty.

Alignment and Balance Methods in Total Knee Arthroplasty

Total knee arthroplasty is one of the most commonly performed orthopaedic surgical procedures in the United States. Primary concepts in the surgical technique include restoring limb alignment and soft-tissue balance about the knee. Currently, traditional mechanical alignment concepts that focus on restoring neutral limb alignment have been challenged by the principle of kinematic alignment. In addition to these recent philosophical challenges, new technologies have been introduced to help the surgeon more accurately achieve optimal limb alignment and soft-tissue balance.

Comparison of Coronal Prosthetic Alignment After Total Knee Arthroplasty Using 3 Computer-Assisted Navigation Systems

Recent advances in surgical tools such as navigation systems have contributed to accurate implantation in total knee arthroplasty. Although several navigation systems have been developed, reports regarding which navigation system has better accuracy are few. Therefore, this study aimed to compare the accuracy of postoperative coronal alignment among 3 navigation systems. A total of 90 knee prostheses were implanted for 90 patients with osteoarthritis. Thirty patients were enrolled in each of the following 3 navigation groups: Stryker Navigation System II (computed tomography-free navigation; Stryker, Mahwah, New Jersey); OrthoPilot version 4.2 navigation system (computed tomography-free navigation; B. Braun Aesculap, Tuttlingen, Germany); and VectorVision navigation system (computed tomography-based navigation system; BrainLAB, Munich, Germany). Thirty consecutive total knee arthroplasties performed via the conventional method without navigation were selected as a control group for comparison with the navigation groups. Postoperative coronal mechanical axis and femoral and tibial coronal component angles were compared among the groups using long-leg standing radiographs for the rate of outliers beyond 3°. No differences were observed in the mean femoral and tibial component angles among the navigation and conventional groups. However, the proportion of outliers beyond 3° was higher in the conventional group than in the 3 navigation groups. No significant differences in the outlying values were found among the 3 navigation groups. These 3 navigation systems achieved equally accurate coronal mechanical alignment with fewer outliers. The navigation systems exhibited more precise implantation than the conventional method. [Orthopedics. 2018; 41(5):e621-e628.].

Gap difference in navigated TKA: a measure of the imbalanced flexion-extension gap

Introduction: The success of Total Knee Arthroplasty (TKA) hinges on balanced flexion-extension gaps. This paper aims to evaluate the correlation between imbalanced gaps and clinical outcomes, and hence help quantify the imbalanced gap in navigation-assisted total knee arthroplasty.

Methods: We studied 195 knees with an average follow-up of two years. Flexion-extension gaps were obtained from computer calculation upon cementation of implants in both flexion (90°) and extension. The gap difference (GD) was defined as the measured difference between the gaps in flexion and extension.

Results: At 2 years after surgery, the mean ROM in the balanced group, with GD less than or equal to 2 mm, was 115.1° ± 16.6° and the mean ROM in the imbalanced group was 116.7° ± 12.1°. This was not statistically significant with p-value 0.589. Balanced flexion-extension gaps also did not show significant difference in terms of mechanical alignment, with 0.29 ± 0.89 in the balanced group at 2 years, and 0.65 ± 1.51 in the imbalanced group with p-value 0.123. Balanced gaps however, were associated with improved outcomes in terms of physical functioning, bodily pain, social functioning, Oxford and Knee scores at 6 months and improved social functioning scores at 2 years.

Conclusions: Computer navigation is a useful tool for assessing the gap balance in TKA. Balanced flexion-extension gaps, with gap differences of less than or equal to 2 mm, is associated with improved clinical outcomes at 6 months.

Can a Single-Use and Patient-Specific Instrumentation Be Reliably Used in Primary Total Knee Arthroplasty? A Multicenter Controlled Study

BACKGROUND

The aim of this controlled multicenter study is to evaluate the clinical and radiologic outcomes of primary total knee arthroplasty (TKA) using single-use fully disposable and patient-specific cutting guides (SU) and compare the results to those obtained with traditional patient-specific cutting guides (PSI) vs conventional instrumentation (CI).

METHODS

Seventy consecutive patients had their TKA performed using SU. They were compared to 140 historical patients requiring TKA that were randomized to have the procedure performed using PSI vs CI. The primary measure outcome was mechanical axis as measured on a standing long-leg radiograph using the hip-knee-ankle angle. Secondary outcome measures were Knee Society and Oxford knee scores, operative time, need for postoperative transfusion, and length of hospital stay.

RESULTS

The mean hip-knee-ankle value was 179.8° (standard deviation [SD] 3.1°), 179.2° (SD 2.9°), and 178.3° (SD 2.5°) in the CI, PSI and SU groups, respectively (P = .0082). Outliers were identified in 16 of 65 (24.6%), 15 of 67 (22.4%), and 14 of 70 (20.0%) knees in the CI, PSI, and SU group, respectively (P = .81). There was no significant difference in the clinical results (P = .29 and .19, respectively). Operative time, number of unit transfusion, and length of hospital stay were not significantly different between the 3 groups (P = .45, .31, and 0.98, respectively).

CONCLUSION

The use of an SU in TKA provided similar clinical and radiologic results to those obtained with traditional PSI and CI. The potential economic advantages of single-use instrumentation in primary TKA require further investigation.

Is Immediate Postoperative Mechanical Axis Associated with the Revision Rate of Primary Total Knee Arthroplasty? A 10-Year Follow-up Study

Background

Achieving neutral limb alignment during total knee arthroplasty (TKA) has been considered an important determinant in the long-term prosthesis survival. The purpose of this study was to evaluate the association between the immediate postoperative mechanical alignment of the lower limb and the rate of revision TKA by comparing an acceptable mechanical axis group (within ± 3° from neutral alignment) and an outlier group (> 3° deviation from neutral alignment).

Methods

Between 2000 and 2006, clinical and radiographic data of 334 primary TKAs were retrospectively reviewed to determine the 10-year Kaplan-Meier survival rate. Patients were divided into acceptable and outlier groups according to the mechanical axis checked postoperatively within a month. Clinical outcomes were assessed using Hospital for Special Surgery, Knee Society Score, and Western Ontario and McMaster Universities Osteoarthritis Index score preoperatively and at the final follow-up. Postoperative complications and revision rates were also evaluated.

Results

The mean change in mechanical axis between the immediate postoperative examination and the last follow-up was greater in the outlier group (1.6 ± 2.7) than in the acceptable group (0.8 ± 2.4). The revision rates were significantly different between the two groups (p = 0.04). At the last follow-up, clinical scores were all improved in both groups compared to each preoperative condition. There were no significant differences in clinical scores between the two groups at the last follow-up. The 10-year Kaplan-Meier survival analysis showed a tendency towards better survival with restoration of neutral mechanical axis. However, the difference was not statistically significant (p = 0.25).

Conclusions

Restoration of neutral limb alignment is a factor that can result in a lower revision rate and higher longevity in TKA. However, there were no significant differences in clinical outcomes between the two groups.

Current concepts and future perspectives in computer-assisted navigated total knee replacement

BACKGROUND

Total knee replacements (TKR) aim to restore stability of the tibiofemoral and patella-femoral joints and provide relief of pain and improved quality of life for the patient. In recent years, computer-assisted navigation systems have been developed with the aim of reducing human error in joint alignment and improving patient outcomes.

METHODS

We examined the current body of evidence surrounding the use of navigation systems and discussed their current and future role in TKR.

RESULTS

The current body of evidence shows that the use of computer navigation systems for TKR significantly reduces outliers in the mechanical axis and coronal prosthetic position. Also, navigation systems offer an objective assessment of soft tissue balancing that had previously not been available. Although these benefits represent a technical superiority to conventional TKR techniques, there is limited evidence to show long-term clinical benefit with the use of navigation systems, with only a small number of studies showing improvement in outcome scores at short-term follow-up. Because of the increased costs and operative time associated with their use as well as the emergence of more affordable and patient-specific technologies, it is unlikely for navigation systems to become more widely used in the near future.

CONCLUSIONS

Whilst this technology helps surgeons to achieve improved component positioning, it is important to consider the clinical and functional implications, as well as the added costs and potential learning curve associated with adopting new technology.

Similar radiological results with accelerometer-based navigation versus conventional technique in total knee arthroplasty

BACKGROUND

The Zimmer iASSIST system is an accelerometer-based, portable navigation device for total knee arthroplasty (TKA) that does not require the use of a large console for alignment feedback as required in computer-assisted surgery. The purpose of this study was to determine the accuracy of the accelerometer-based system in component positioning and overall mechanical alignment.

METHODS

Two groups of 30 patients each with primary osteoarthritis underwent TKA using either conventional method or Zimmer iASSIST navigation in 2013 was retrospectively studied. Patients were matched according to body mass index (BMI), gender and age. A senior arthroplasty surgeon performed all the operation using the same surgical approach. Perioperative and post-operative regimens were the same. All patients had standardized radiographs performed post-operatively to determine the lower limb mechanical alignment and component placement.

RESULTS

There was no difference between the two groups for age, BMI, gender, side of operated knee and preoperative mechanical axis ( p > 0.05). There was no difference in the proportion of outliers for mechanical axis ( p = 0.38), coronal femoral angle ( p = 0.50), coronal tibia angle ( p = 0.11), sagittal femoral angle ( p = 0.28) and sagittal tibia angle ( p = 0.33). The duration of surgery, post-operative drop in haemoglobin level and transfusion incidence did not show statistically significant differences between the two groups ( p > 0.05).

CONCLUSIONS

Our article showed that iASSIST was safe and remains a useful tool to restore mechanical axis. However, our data demonstrated no difference in lower limb alignment and component placement between the TKA that used accelerometer-based system and those that underwent conventional method.

Computer-Assisted Total Knee Arthroplasty: Is There a Difference Between Image-Based and Imageless Techniques?

BACKGROUND

Image-based and imageless computer-assisted total knee arthroplasty (CATKA) has become increasingly popular. This study aims to compare outcomes, including perioperative complications and transfusion rate, between CATKA and conventional total knee arthroplasty (TKA), as well as between image-based and imageless CATKA.

METHODS

Using the 9th revision of the International Classification of Diseases codes, we queried the Nationwide Inpatient Sample database from 2005 to 2011 to identify unilateral conventional TKA, image-based, and imageless CATKAs as well as in-hospital complications and transfusion rates.

RESULTS

A total of 787,809 conventional TKAs and 13,246 CATKAs (1055 image-based and 12,191 imageless) were identified. The rate of CATKA increased 23.13% per year from 2005 to 2011. Transfusion rates in conventional TKA and CATKA cases were 11.73% and 8.20% respectively (P < .001) and 6.92% in image-based vs 8.27% in imageless (P = .023). Perioperative complications occurred in 4.50%, 3.47%, and 3.41% of cases after conventional, imageless, and imaged-based CATKAs, respectively. Using multivariate analysis, perioperative complications were significantly higher in conventional TKA compared to CATKA (odds ratio = 1.17, 95% confidence interval 1.03-1.33, P = .01). There was no significant difference between imageless and image-based CATKA (P = .34). Length of hospital stay and hospital charges were not significantly different between groups (P > .05).

CONCLUSION

CATKA has low complication rates and may improve patient outcomes after TKA. CATKA, especially the image-based technique, may reduce in-hospital complications and transfusion without increasing hospital charges and length of hospital stay significantly. Large prospective studies with long follow-up are required to verify potential benefits of CATKA.