Computer Navigated Total Knee Arthroplasty: Rates of Adoption and Early Complications

Technology in Total Knee Arthroplasty in 2023

Over the past few decades, instrumentation and techniques for total knee arthroplasty have evolved from conventional manual tools to a wide range of technologies, including calibrated guides for accurate bone cuts and alignment, smart tools, dynamic intraoperative sensors for soft tissue balancing, patient-specific guides, computer navigation, and robotics. This review is intended to provide an overview of the latest advancements in total knee arthroplasty technology, address potential challenges and solutions related to the application of these technologies, and explore their limitations.

Lower Perioperative Complication Rates and Shorter Lengths of Hospital Stay Associated With Technology-Assisted Total Knee Arthroplasty Versus Conventional Instrumentation in Primary Total Knee Arthroplasty

BACKGROUND

The use of technology allows increased precision in component positioning in total knee arthroplasty (TKA). The objectives of this study were to compare (1) perioperative complications and (2) resource utilization between robotic-assisted (RA) and computer-navigated (CN) versus conventional (CI) TKA.

METHODS

A retrospective cohort study was performed using a national database to identify patients undergoing unilateral, primary elective TKA from January 2016 to December 2019. A total of 2,174,685 patients were identified and included RA (69,445), CN (112,225), or CI (1,993,015) TKA. Demographics, complications, lengths of stay, dispositions, and costs were compared between the cohorts. Binary logistic regression analysis was performed.

RESULTS

The RA TKA cohort had lower rates of intraoperative fracture (0.05 versus 0.08%, P < .05), respiratory complications (0.6 versus 1.1%, P < .05), renal failure (1.3 versus 1.7%, P < .05), delirium (0.1 versus 0.2%, P < .05), gastrointestinal complications (0.04 versus 0.09%, P < .05), postoperative anemia (8.9 versus 13.9%, P < .05), blood transfusion (0.4 versus 0.9%, P < .05), pulmonary embolism, and deep vein thrombosis (0.1 versus 0.2%, P < .05), and mortality (0.01 versus 0.02%, P < .05) compared to conventional TKA, though the cohort did have higher rates of myocardial infarction (0.09 versus 0.07%, P < .05). The CN cohort had lower rates of myocardial infarction (0.02 versus 0.07%, P < .05), respiratory complications (0.8 versus 1.1%, P < .05), renal failure (1.5 versus 1.7%, P < .05), blood transfusion (0.8 versus 0.9%, P < .05), pulmonary embolism (0.08 versus 0.2%, P < .05), and deep vein thrombosis (0.2 versus 0.2%, P < .05) over CI TKA. Total cost was increased in RA (16,190 versus $15,133, P < .05) and CN (17,448 versus $15,133, P < .05). However, the length of hospital stay was decreased in both RA (1.8 versus 2.2 days, P < .05) and CN (2.1 versus 2.2 days, P < .05).

CONCLUSIONS

Technology-assisted TKA was associated with lower perioperative complication rates and faster recovery.

The Alignment of the Tibial Component in Total Knee Arthroplasty: Is a Technology-Assisted System Better Than Conventional Instrumentation?

Background Technologies such as navigation and robotics are aimed at improving tibial alignment in total knee arthroplasties (TKA) and eliminating the errors resulting from the use of manual instrumentation. Methods This prospective study analyzed 130 arthroplasties in order to determine whether navigation can improve the frontal mechanical axis of the tibia and whether the postoperative angulation of this axis differs from the preoperative one. The mean patient age was 71.8 years, and the mean BMI was 31.17. Eighty-six patients were female. The same cemented TKA model and the same imageless navigation system were used in all cases. Results The mean postoperative tibial angle following implantation was 87.65°, without any statistically significant differences with respect to the previous angulation. However, navigation was seen to result in a nearly neutral tibial axis, a larger number of cases (41.5%-60.8% {p = 0.002}) aligned within the safe zone (90° ± 3°), a smaller number of outliers, and a clustering of values around the mean. Conclusions Navigation improves the frontal positioning of the tibial component in total knee arthroplasties but does not offer any advantages as compared with conventional instrumentation.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis

BACKGROUND

The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA.

METHODS

We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate.

RESULTS

Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA.

CONCLUSIONS

Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

Anaesthetic nurse specialist role in perioperative anaesthetic management of patients who are morbidly obese

This integrative literature review examined the role of an anaesthetic nurse specialist (ANS) in the perioperative anaesthetic nursing management of morbidly obese patients associated with elective orthopaedic surgery. The responsibility of the ANS is to provide high-quality perioperative anaesthetic care to ensure patient safety. Morbid obesity is increasing globally, with significant implications for healthcare delivery, care and treatment, including perioperative care. The Association of Anaesthetists of Great Britain and Ireland emphasises that the perioperative management of these patients presents significant organisational and practical issues. However, there are limited data or guidelines on whether surgeons, anaesthetists and nurses routinely take special precautions in managing morbidly obesity patients undergoing elective orthopaedic operative procedures. The authors carried out a search of databases, followed by an integrated literature review and synthesis of 11 studies. The main findings revealed significant clinical challenges and resource requirements for perioperative anaesthetic management of this patient group. Recommendations are made to prepare for and manage these surgical patients, from preoperative assessment to postoperative care.

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.

A comparison of utilization and short-term complications of technology-assisted versus conventional total knee arthroplasty

Background

While technology-assisted total knee arthroplasty (TA-TKA) improves implant positioning, whether it confers improved clinical outcomes remains inconclusive. We sought to examine national TA-TKA utilization trends and to compare outcomes between TA-TKA and unassisted TKA (U-TKA).

Methods

Patients who underwent primary, elective TKA from 2010 to 2018 were identified using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Demographic, perioperative, and 30-day outcomes were collected. Patients were stratified on the basis of whether they underwent TA-TKA, which included computer navigation and robotics, or U-TKA. The proportion of patients undergoing TKA using TA-TKA was calculated. One-to-one propensity-score matching paired patients undergoing TA-TKA or U-TKA. Independent samples t-tests and Mann–Whitney U tests were used to compare continuous variables, and chi-squared tests were used to compare categorical variables.

Results

Of the 402,284 TKA patients, 10,429 (2.6%) cases were performed using TA-TKA. Comparing the unmatched TA-TKA and U-TKA groups, race (p < 0.001), smoking status (p = 0.050), baseline functional status (p < 0.001), and body mass index (BMI) (p < 0.001) significantly differed. Propensity-score matching yielded 8633 TA-TKA and U-TKA pairs. The TA-TKA cohort had shorter hospital length of stay (LOS) (2.7 ± 2.5 versus 2.8 ± 1.9 days, p = 0.017) but similar operative times (92.4 ± 33.4 versus 92.6 ± 39.8 min, p = 0.670). Compared with the U-TKA group, the TA-TKA group had lower major complication (7.6% versus 9.4%, p < 0.001) and transfusion (3.9% versus 5.1%, p < 0.001) rates and higher rates of discharge to home (73.9% versus 70.4%, p < 0.001). Reoperation and readmission rates did not significantly differ between groups.

Conclusions

TA-TKA utilization remains low among orthopedic surgeons. Compared with U-TKA, TA-TKA yielded improved perioperative and 30-day outcomes. Nonetheless, surgeons must consider the benefits and drawbacks of TA-TKA when determining the proper surgical technique and technology for each patient.

Level III evidence

Retrospective cohort study.

Computer-Navigated and Robotic-Assisted Total Knee Arthroplasty: Increasing in Popularity Without Increasing Complications

BACKGROUND

Data on the clinical impact of computer navigation (CN) and robotic assistance (RA) in total knee arthroplasty (TKA) are mixed. This study aims to describe modern utilization trends in CN-TKA, RA-TKA, and traditionally-instrumented (TD) TKA and to assess for differences in postoperative complications and opioid consumption by procedure type.

METHODS

A national database was queried to identify primary, elective TKA patients from 2015 to 2020. Trends in procedural utilization rates were assessed. Differences in 90-day postoperative complications and inpatient opioid consumption were assessed. Multivariate regression analyses were performed to account for potential confounders.

RESULTS

Of the 847,496 patients included, 49,317 (5.82%) and 24,460 (2.89%) underwent CN-TKA and RA-TKA, respectively. CN-TKA utilization increased from 5.64% (2015) to 6.41% (2020) and RA-TKA utilization increased from 0.84% (2015) to 5.89% (2020). After adjusting for confounders, CN-TKA was associated with lower periprosthetic joint infection (P = .001), pulmonary embolism (P < .001), and acute respiratory failure (P = .015) risk compared to traditional (TD) TKA. RA-TKA was associated with lower deep vein thrombosis (P < .001), myocardial infarction (P = .013), and pulmonary embolism (P = .001) risk than TD-TKA. Lower postoperative day 1 opioid usage was seen with CN-TKA and RA-TKA than TD-TKA (P < .001). Lower postoperative day 0 opioid consumption was also seen in RA-TKA (P < .001).

CONCLUSION

From 2015 to 2020, there was a relative 13.7% and 601.2% increase in CN-TKAs and RA-TKAs, respectively. This trend was associated with reductions in hospitalization duration, postoperative complications, and opioid consumption. These data support the safety of RA-TKA and CN-TKA compared to TD-TKA. Further investigation into the specific indications for these technology-assisted TKAs is warranted.

Analysis of New Orthopaedic Technologies in Large Database Research

Improvements in orthopaedic surgery go hand in hand with technological advances. The present article outlines the historical and current uses of large databases and registries for the evaluation of new orthopaedic technologies, providing insights for future utilization, with robotic-assisted surgery as the example technology.

[Future implications of navigation in total knee arthroplasty]

BACKGROUND

After more than two decades of experience with computer-assisted knee arthroplasty, extensive experience and study data are available, allowing a profound evaluation. Undoubtedly, computer-assisted knee arthroplasty has been proven to achieve excellent results for implant positioning and long-leg axis reconstruction. Thus, computer-assisted knee arthroplasty represents the current gold standard to avoid unintended malpositioning of total knee components for neutrally aligned implants and individualized implant alignment (kinematic alignment, adjusted mechanical alignment, and others). Previous studies could not show significant differences in functional outcomes and patient satisfaction. However, recent meta-analyses showed relevant advantages of computer-assisted knee arthroplasty. These results could be based on further developments in software-assisted soft tissue balancing and more sensitive evaluation methods of follow-up examinations.

LONG-TERM OUTCOME

Further, international registries show advantages of computer-assisted knee arthroplasty regarding long-term outcomes. In particular, the Australian arthroplasty registry describes a significantly lower revision rate due to aseptic loosening/osteolysis in the computer-assisted knee arthroplasty group, analyzing a period of up to 17 years. These positive effects can already be proven six months following surgery.

FUTURE PROSPECTS

However, despite demonstrated benefits, computer-assisted knee arthroplasty has not yet become established in daily routine, and wide regional variations in its use are observed. Newer developments such as robotic-assisted knee arthroplasty, primarily based on navigation techniques, are currently being heavily promoted. However, this new technology must justify its enormous additional costs and prove its advantages compared to computer-assisted knee arthroplasty. In the backdrop of the development of computer-assisted knee arthroplasty, this might be a difficult task.

Adverse Events Associated With Robotic-Assisted Joint Arthroplasty: An Analysis of the US Food and Drug Administration MAUDE Database

BACKGROUND

The use of robotic assistance in arthroplasty is increasing; however, the spectrum of adverse events potentially associated with this technology is unclear. Improved understanding of the causes of adverse events in robotic-assisted arthroplasty can prevent future incidents and enhance patient outcomes.

METHODS

Adverse event reports to the US Food and Drug Administration Manufacturer and User Facility Device Experience database involving robotic-assisted total hip arthroplasty (THA), total knee arthroplasty (TKA), and partial knee arthroplasty were reviewed to determine causes of malfunction and related patient impact.

RESULTS

Overall, 263 adverse event reports were included. The most frequently reported adverse events were unexpected robotic arm movement for TKA (59/204, 28.9%) and retained registration checkpoint for THA (19/44, 43.2%). There were 99 reports of surgical delay with an average delay of 20 minutes (range 1-120). Thirty-one cases reported conversion to manual surgery. In total, 68 patient injuries were reported, 7 of which required surgical reintervention. Femoral notching (12/36, 33.3%) was the most common for TKA and retained registration checkpoint (19/28, 67.9%) was the most common for THA. Although rare, additional reported injuries included femoral, tibial, and acetabular fractures, MCL laceration, additional retained foreign bodies, and an electrical burn.

CONCLUSION

Despite the increasing utilization of robotic-assisted arthroplasty in the United States, numerous adverse events are possible and technical difficulties experienced intraoperatively can result in prolonged surgical delays. The events reported herein seem to indicate that robotic-assisted arthroplasty is generally safe with only a few reported instances of serious complications, the nature of which seems more related to suboptimal surgical technique than technology. Based on our data, the practice of adding registration checkpoints and bone pins to the instrument count of all robotic-assisted TJA cases should be widely implemented to avoid unintended retained foreign objects.

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.

Trends in Practice Patterns of Conventional and Computer-assisted Knee Arthroplasty: An Analysis of 570,671 Knee Arthroplasties Between 2010 and 2017

BACKGROUND

Despite advances in computer-assisted knee arthroplasty (CAKA), little is known about the uptake of this technology in recent years. We aimed to explore the utilization trends and practice variation of CAKA from 2010 to 2017 and investigate the predictors of CAKA adoption.

METHODS

Patients undergoing conventional knee arthroplasty and CAKA were identified from the states of New York and Florida's administrative databases using the International Classification of Diseases version 9 and 10 procedure codes. Quarterly proportions of CAKA were calculated over the study period, and logistic regression was used to estimate predictors of CAKA utilization.

RESULTS

Between 2010 and 2017, quarterly proportion of CAKAs increased from 4.89% in 2010Q1 to 9.45% in 2017Q3 in New York and from 4.03% in 2010Q1 to 5.73% in 2017Q3 in Florida. The general CA code was used to code most of the procedures (81%). Being Black (odds ratio [OR]: 0.63, 95% confidence interval [CI], 0.60 to 0.67), Hispanic (OR: 0.45, CI, 0.41 to 0.50), and having Medicaid coverage (OR: 0.46, CI, 0.40 to 0.53) were associated with lower likelihood of receiving CAKA in New York; similar findings were found in Florida.

CONCLUSION

Utilization of CAKA has increased substantially in both New York and Florida from 2010 to 2017; however, with most CAKAs reported using the general code, understanding adoption rates of various modalities was not possible. Black and Hispanic patients and those with Medicaid insurance are least likely to receive this high-precision technology, illustrating the presence of disparities in the adoption of CAKA.

The Impact of Mental Illness on Postoperative Adverse Outcomes After Outpatient Joint Surgery

BACKGROUND

The effect of pre-existing mental illness on outpatient surgical outcomes is not well characterized. The objective of this study was to evaluate the association between pre-existing mental illness diagnosis and postoperative complications after outpatient total knee (TKA) and total hip arthroplasty (THA) and 2) compare with inpatient total joint arthroplasty (TJA).

METHODS

The Mariner Claims Database was used to capture patients undergoing outpatient TJA from 2010 to 2017. Patients were grouped into three categories: those with an existing history of anxiety and/or depression, those with severe mental illness, and those without history of mental illness. Additional subgroup analysis compared those with severe mental illness undergoing outpatient vs inpatient TJA. Outcomes were analyzed using multivariable logistic regression (P < .05).

RESULTS

Patients undergoing outpatient TJA with prior history of anxiety and/or depression or severe mental illness had an increased risk of emergency department (ED) visits (TKA, P < .001; THA, P = .014) within 90 days compared with those without history of mental illness. Severe mental illness was also associated with increased risk of medical complications at 90 days (TKA, P < .001; THA, P = .006). When compared with those undergoing inpatient surgery, patients undergoing outpatient TKA with severe mental illness were at increased risk of periprosthetic infection (P = .005) and ED visit (P = .003) within 90 days of surgery.

CONCLUSION

Anxiety/depression and severe mental illness are associated with higher rates of ED visits after outpatient TJA. Patients with severe mental illness also experienced more adverse events, whereas those with anxiety and/or depression had similar rates compared with control. A higher rate of adverse outcomes was seen after TKA in patients with severe mental illness when surgery was performed in the outpatient setting vs those that had surgery as an inpatient.

LEVEL OF EVIDENCE

III.

Reduced postoperative morbidity in computer-navigated total knee arthroplasty: A retrospective comparison of 225,123 cases

BACKGROUND

Total knee arthroplasty (TKA) is one of the most common elective surgical procedures in the United States, with more than 650,000 performed annually. Computer navigation technology has recently been introduced to assist surgeons with planning, performing, and assessing TKA bone cuts. The aim of this study is to assess postoperative complication rates after TKA performed using computer navigation assistance versus conventional methods.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was queried for unilateral TKA cases from 2008 to 2016. The presence of the CPT modifier for use of computer navigation was used to separate cases of computer-navigated TKA from conventional TKA. Multivariate and propensity-matched logistic regression analyses were performed to control for demographics and comorbidities.

RESULTS

There were 225,123 TKA cases included; 219,880 were conventional TKA (97.7%) and 5,243 were navigated (2.3%). Propensity matching identified 4,811 case pairs. Analysis demonstrated no significant differences in operative time, length of stay, reoperation, or readmission, and no differences in rates of post-op mortality at 30 days postoperatively. Compared to conventional cases, navigated cases were at lower risk of serious medical morbidity (18% lower, p = 0.009) within the first 30 days postoperatively.

CONCLUSION

After controlling for multiple known risk factors, navigated TKA patients demonstrated lower risk for medical morbidity, predominantly driven by lower risk for blood transfusion. Given these findings, computer-navigation is a safe surgical technique in TKA.

Navigation assisted total knee arthroplasty in 54,114 patients: No increased risk in acute complications and hospital utilisation

BACKGROUND

The advent of navigation in total knee arthroplasty (TKA) has generated interest in attempt to improve component positioning as desired and clinical outcomes. The aim of this study was to evaluate 90-day complication and cost of navigation-assisted TKAs (NTKA) compared to conventional TKAs (CTKA) using a national database.

METHODS

A retrospective review of national database was conducted on all patients who underwent TKA from 2010 and 2017. The cohort was stratified into NTKA and CTKA subcohorts, excluding cases utilizing robotics.

RESULTS

NTKA was associated with a significant decrease in 90-day postoperative major and minor complications. NTKA was also associated with a decrease in 90-day hospital utilization with lower rates of emergency department visits and readmissions. The cost of hospitalization and total 90-day costs were lower in NTKA, with an average savings of $800.

CONCLUSION

The adoption of navigation in TKA is safe and efficaceous compared to CTKA.

LEVEL OF EVIDENCE

III. Retrospective cohort study.

Complications of computer-assisted navigation in total knee replacement: retrospective cohort of eight hundred and seventy eight consecutive knees

PURPOSE

The main objective was to analyze the computer-assisted navigation (CAN)-specific complications that forced to switch to conventional procedure in primary total knee replacement (TKR). The secondary objective was to determine the influence of those complications on TKR short-term survival.

METHODS

Retrospective study of 878 primary TKR in 753 patients. Two consecutive versions of the OrthoPilot navigation system (Braun Aesculap, Germany) were used during the study time. Specific complications of CAN were defined as those due to the instrumentation (hardware or software failures), which were classified in one of two categories according to whether they occurred during the registration or tracking process.

RESULTS

There were 20 (2.3%) complications related to the navigation system use that forced to switch to conventional surgery: in 11 (1.2%) knees due to loosening of the tracking pins, and in the other nine (1.0%) there were information system failures. There was a trend for a higher conversion rate to conventional surgery with the use of the first version of the software. There were no fractures, infections, or nerve injuries at the pin site. We found no differences in the distribution of baseline variables among those with or without conversion to conventional surgery. There was no significant difference (p = 0.488) in the two year survival between patients with or without conversion.

CONCLUSION

CAN for primary TKR is a safe method with few specific complications that forced to switch from the navigated to the conventional procedure. Conversion to conventional surgery did not affect the short-term survival of TKR.

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.

Computer assisted total knee arthroplasty: a real navigation to better results?

BACKGROUND AND AIM OF THE WORK

Computer assisted surgery in knee replacement is still in discussion, but majority of papers affirm an increase of the accuracy in alignment. Aim of our study is to evaluate the accuracy of mechanical axis, the posterior tibial slope and the femoral component rotation with navigation, x-ray and CT data.

METHODS

We have analysed 145 patients who underwent total knee arthroplasty between January 2012 and December 2014. We have checked each patient at 6, 12 and 24 months of follow-up. During each visit, we did a clinical evaluation checking the ROM and a clinical score (KOOS). At 2 years, we did a CT evaluation and a plain x-ray evaluation.

RESULTS

125 patients have completed the follow-up. Mean follow-up time was 2,6 years. Both ROM and KOOS values increased during follow-up. About the mechanical axis, both x-ray and CT data showed a mean deviation <2° from the target. About posterior tibial slope and femoral component rotation, CT data showed a mean deviation of <3° from the target. Mean difference between navigation and CT data was <1°.

CONCLUSIONS

According to literature data, our data confirm that computer assisted surgery in knee replacement have a good accuracy of coronal alignment, rotational alignment and posterior tibial slope.