Computer-navigated Total Knee Arthroplasty Research Articles

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

BackgroundThe 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. MethodsA 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. ResultsThe 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). ConclusionsTechnology-assisted TKA was associated with lower perioperative complication rates and faster recovery.

What's New in Adult Reconstructive Knee Surgery.

What's New in Adult Reconstructive Knee Surgery.

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

BackgroundComputer 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. MethodsAn 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. ResultsA 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). ConclusionThe 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.

Short-Term Benefits of Robotic Assisted Total Knee Arthroplasty Over Computer Navigated Total Knee Arthroplasty Are Not Sustained With No Difference in Postoperative Patient-Reported Outcome Measures.

BackgroundThe purpose of this study was to compare early clinical and patient-reported outcomes between robotic assisted (RA) and computer navigation (CN) total knee arthroplasty (TKA).MethodsOne hundred and fifty patients were enrolled in this prospective, single-surgeon, cohort study, with 75 patients each receiving CN-TKA or RA-TKA in a consecutive series. There were no differences in patient age (P = .34) or body mass index (P = .09), but a higher proportion of males underwent RA-TKA (P = .03). We recorded hospital knee pain, analgesic usage, length of hospital stay, range of motion, and patient-reported outcome measures postoperatively for both patient cohorts.ResultsHospital length of stay was shorter for the RA-TKA patients (P < .001). RA-TKA patients showed improved range of motion (P < .001) and decreased pain scores (P = .006) on day 1. Subsequent days showed no significant differences. Narcotic usage was lower for the RA-TKA group on day 2 postoperatively (P = .03) and onwards. Total morphine equivalent dose was also significantly lower for the RA-TKA than for the CN-TKA group (P < .001). There was no difference in Forgotten Joint Score (P = .24) or Oxford Knee Score (P = .51) between groups at 2 years postoperatively.ConclusionThe use of RA-TKA demonstrated reduced postoperative analgesia usage and length of stay. There were no differences seen between CN-TKA and RA-TKA with respect to clinical outcomes at 2 years after surgery.

Implementation of robotic-assisted total knee arthroplasty in the public health system: a comparative cost analysis.

Robotic-assisted total knee arthroplasty (TKA) may improve the precision of bone preparation and component alignment when compared to the conventional surgical approach; however, the detailed cost analysis of robotic-assisted TKA is lacking. This study aims to compare in-hospital costs between robotic-assisted and computer-navigated TKA. Patients undergoing primary TKA at a public hospital in Sydney between October 2018 and June 2019 were included. Patient demographics, surgical outcomes and in-hospital cost variables including, staff, critical care, emergency department, diagnostic, prosthesis, operating room, ward and other related costs until the discharge to the community were collected. Differences across in-hospital costs between robotic-assisted and computer-navigated TKA were compared using independent Student's t-tests. Of the 258 primary TKAs, 181 (70.2%) were computer-navigated and 77 (29.8%) robotic-assisted. Surgical time (p < 0.001) and operating time (p < 0.001) were both significantly shorter in computer-navigated TKA, while robotic-assisted TKA cases were more likely to be discharged directly home without extended in-patient rehabilitation (p = 0.014). When removing the capital costs of surgical equipment and maintenance, there was no difference in total in-hospital cost between computer-navigated ($19,512.3) and robotic-assisted TKA ($18,347.1; p = 0.179). When these capital costs were included, the mean in-hospital cost of robotic-assisted surgery was $21,507.6 compared to $19,659.7 for computer-navigated TKA (p = 0.034). The total in-hospital cost, during the implementation period of robotic-assisted TKA, is comparable with computer-navigated TKA. Robotic-assisted TKA was significantly more expensive when the upfront cost of the robotic system and maintenance costs were included. Longer term cost benefit of robotic-assisted TKA should be investigated in future studies.

Tibial joint line orientation has no effect on joint awareness after mechanically aligned total knee arthroplasty.

Joint line orientation (JLO) plays an important role in total knee arthroplasty (TKA), but its influence on patient-reported outcomes (PROs) is unclear. The purpose of this study was to examine JLO impact as measured by the forgotten joint score (FJS-12). The hypothesis was that restoring the joint line(JL) parallel to the floor would influence joint awareness favorably, i.e., allow the patient to forget about the joint in daily living. All computer-navigated primary TKAs using a cemented, cruciate-retaining (CR) design implanted between January 2018 and September 2019 were reviewed in this retrospective single-center analysis. Primary endpoints were: clinical [range of motion (ROM)], and patient-reported (FJS-12) and radiographical outcomes [tibia joint line angle (TJLA), hip knee axis (HKA), mechanical medial proximal tibia angle (mMPTA) as well as mechanical lateral distal femoral angle (mLDFA)]. Seventy-six patients (mean age: 70.3 ± 9.7years, mean BMI: 29.7 ± 5.2kg/m2) were included. Postoperative ROM averaged 118.7 ± 9.6°. The mean FJS-12 improved from 16.4 ± 15.3 (preoperatively) to 89.4 ± 16.9 (1-year follow-up; p < 0.001). Clinical outcomes and PROs did not correlate with JLO (p = n.s.). Cluster analysis using six measures revealed that a medially opened TJLA was associated with significantly better postoperative FJS-12. Tibial JLO was found to have no effect on PROs. Considering the JLO in the coronal plane alone probably has questionable clinical relevance. Lower limb alignment should be assessed in all three planes and correlated with the clinical outcome. Level IV.

Clinical outcomes associated with robotic and computer-navigated total knee arthroplasty: a machine learning-augmented systematic review.

Robotic (RTKA) and computer-navigated total knee arthroplasty (CNTKA) are increasingly replacing manual techniques in orthopaedic surgery. This systematic review compared clinical outcomes associated with RTKA and CNTKA and investigated the utility of natural language processing (NLP) for the literature synthesis. A comprehensive search strategy was implemented. Results of included studies were combined and analysed. A transfer learning approach was applied to train deep NLP classifiers (BERT, RoBERTa and XLNet), with cross-validation, to partially automate the systematic review process. 52 studies were included, comprising 5,067 RTKA and 2,108 CNTKA. Complication rates were 0-22% and 0-16% and surgical time was 70-116 and 77-102min for RTKA and CNTKA, respectively. Technical failures were more commonly associated with RTKA (8%) than CNTKA (2-4%). Patient satisfaction was equivalent (94%). RTKA was associated with a higher likelihood of achieving target alignment, less femoral notching, shorter operative time and shorter length of stay. NLP models demonstrated moderate performance (AUC = 0.65-0.68). RTKA and CNTKA appear to be associated with similarly positive clinical outcomes. Further work is required to determine whether the two techniques differ significantlywith regard to specific outcome measures. NLP shows promise for facilitating the systematic review process.

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

BackgroundTotal 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. MethodsThe 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. ResultsThere 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. ConclusionAfter 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.

False malalignment after computer-navigated total knee arthroplasty

BackgroundAlthough computer navigation has improved component alignment in total knee arthroplasty (TKA), radiographic outliers are reported with a wide range in literature even using this technique. We hypothesized that the postoperative malalignment after computer-navigated TKA was partially derived from the inherent problems with two-dimensional (2D) measurement such as inaccuracies in measurement due to the knee position during the radiographic examination and the direction of the X-ray beam. We therefore conducted this study to determine how often knees with malalignment on 2D imaging were truly mal-aligned on three-dimensional (3D) reconstructed imaging. MethodsSixty-two computer-navigated primary TKAs performed in 47 patients were included in this study. In all cases, a weight-bearing long-leg radiograph was obtained after TKA. 3D measurements were performed for outliers 2° or more in coronal alignment of the femoral or tibial component. ResultsFor the 18 femoral mal-aligned components on 2D imaging, eight (44.4%) were not truly mal-aligned on 3D imaging (P = 0.0014). For the eight tibial mal-aligned components on 2D imaging, all knees (100%) were not truly mal-aligned on 3D imaging (P < 0.0001). ConclusionsA considerable number of the false malalignments were included on 2D measurement. Postoperative component alignment in the computer-navigated TKA might be much better than previously reported.

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

ObjectiveIn 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. MethodsWe 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. ResultsThe 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. ConclusionObesity has no influence on mid-term clinical, functional, and radiological results after computer navigated TKA, done by gap balancing technique. Level of evidenceTherapeutic level II.

C-reactive protein course after classical complication free total knee arthroplasty using navigation

PurposeThe purpose is to estimate the degree of normalization of C-reactive protein (CRP) at 2 weeks and 4 weeks after uncomplicated total knee arthroplasty (TKA) using computer navigation. We also wish to determine whether the degree of normalization of CRP at 2 and 4 weeks differs after TKA performed in one knee and after TKA performed sequentially in both knees. We also want to analyze the patient factors that may influence the normalization of CRP.Material and methodsWe studied 400 knees who underwent primary computer-navigated TKA for treatment of advanced osteoarthritis: the TKAs were all performed by the same surgeon. We retrospectively analyzed CRP levels during the preoperative period, the early postoperative period (5–7 days), the 2-week postoperative period (12–14 days), and the 4-week postoperative period (25–30 days). We have assumed gender, age, body mass index (BMI), staged bilateral TKA, and preoperative CRP as the potential patient factors associated with CRP normalization.ResultsIn unilateral TKA, CRP was normalized in 94 cases (34.3%) and in 219 cases (81.4%) within 2 weeks and 4 weeks after surgery, respectively. In second-knee, staged bilateral TKA, CRP was normalized in 46 cases (35.1%) and in 104 cases (79.4%) within 2 weeks and 4 weeks after surgery, respectively. There were no statistical differences between unilateral TKA and second-knee, staged bilateral TKA during the 2-week postoperative and the 4-week postoperative period. Compared to women, men were 1.99 times less likely to have normalized CRP at 2 weeks after surgery (P = 0.02).ConclusionCRP was less likely to normalize during the 2-week postoperative period in men than it is in women, while there was no difference between men and women in the normalization of CRP during the 4-week postoperative period. There were no statistical differences in the course of CRP levels after unilateral TKA and staged bilateral TKA during the 2-week postoperative and the 4-week postoperative period.

Accelerometer-Based, Computer-Navigated Total Knee Arthroplasty to Correct a Complex Deformity in a Patient With Multiple Hereditary Exostoses

BackgroundAccelerometer-based computer-assisted navigation systems (ABCANSs) have been shown to improve alignment accuracy in total knee arthroplasty (TKA) and are effective in treating complex extra-articular deformity. We present an ABCANS-assisted TKA performed in a 68-year-old male with end-stage arthritis of the right knee, in the setting of a severe valgus deformity secondary to multiple hereditary exostoses.MethodsThe KneeAlign 2 system (OrthAlign, Inc.; Aliso Viejo, CA) was used to perform the TKA in this clinical scenario, given its functionality, which allows angular correction to be tailored to a given deformity, and its reported accuracy in performance of bony resection in TKA. The patient was prospectively followed up for one year postoperatively. Radiographs, PROMs, and patient satisfaction were reported.ResultsAfter the ABCANS-assisted TKA, the patient's alignment was improved from 25° to 4° of valgus. His final range of motion was 0-135° without an instability. In addition, the patient reported excellent scores on multiple joint-specific outcome measures, including the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the Forgotten Joint Score, and the Oxford Knee Score.ConclusionThis case report illustrates the rationale, technique, and the excellent clinical outcomes achieved in a complex patient with extra-articular deformity using an ABCANS-assisted TKA.

No difference in radiolucent lines after TKA: a matched-pair analysis of the classic implant and its evolutional design.

Total knee arthroplasty (TKA) designs evolve continuously to improve patient outcomes. However, incidences of radiolucent lines (RLL) in the latest TKA system have recently been reported, raising concerns. The purpose of the current study was to compare radiographic outcomes of this new TKA implant to its predecessor design. A group of 100 patients undergoing TKA using the newer design (Attune) was matched by age and gender to 191 patients with the classic design (LCS). All patients underwent computer-navigated primary TKA by the same surgeon using the same technique. Radiographs were taken before discharge, and 2 and 12months postoperatively. Radiographic analysis was performed independently by three assessors, using the Modern Knee Society Radiographic Evaluation System and Methodology (MKSRES). At 12months postoperatively, the incidence of RLL did not statistically differ between the two implants (14%, n = 14 Attune vs. 8% n = 17 LCS, n.s.). The posterior femoral flange was most commonly affected (12%; n = 12 Attune vs. 7.9%; n = 15 LCS, n.s.) followed by the anterior flange (1%; n = 1 Attune vs. 3.1%; n = 6 LCS, n.s.). The tibial baseplate was only affected in 1% (n = 1) of the Attune and 2.6% (n = 5) of the LCS (n.s.). At 12months follow-up we found no significant difference in RLL between the two implants. Both Attune and LCS TKA systems showed RLL predominantly at the posterior femoral flange. The reasons for the RLL remain a matter of speculation; however, shortcomings in surgical and cementing techniques seem to be more important than implant-related factors. III.

No differences in mid- to long-term outcomes of computer-assisted navigation versus conventional total knee arthroplasty.

Accurate implant position in total knee arthroplasty (TKA) can potentially lead to better long-term functional outcomes and implant survival. Recent studies on whether better clinical results could be obtained from computer-navigated or conventional TKA were inconclusive. In addition, recent reviews only included short-term follow-up studies without performing quantitative mid- to long-term follow-up analysis. Thus, the purpose of the present study was to perform a meta-analysis comparing mid- to long-term clinical outcomes (such as knee scoring and functional results) and radiological outcomes (such as normal alignment of the limb axis or component) between computer-navigated TKA and conventional TKA to determine which method of TKA could obtain better clinical and radiological results. MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and SCOPUS electronic databases were searched for relevant articles published through August 2018 that compared outcomes of computer-navigated TKA and conventional TKA. Data search, extraction, analysis, and quality assessment were performed according to the Cochrane Collaboration guidelines. Clinical and radiological outcomes of both techniques were evaluated using various outcome measures. Seven randomized controlled trials were included. Based on Knee Society Scores, the Western Ontario and McMaster Universities Osteoarthritis Index, pain, and range of motion, there were no significant differences in clinical outcomes between the two techniques. Based on outliers from the normal axis, outliers of femoral components in the coronal plane, and outliers of tibial components in the coronal plane, radiologic outcomes showed no significant differences between the two techniques either. The present study revealed that there were no significant differences in clinical or radiological outcomes between computer-navigated TKA and conventional TKA. It remains unclear which TKA technique yields better results in terms of mid- to long-term clinical and radiological outcomes. I.

Clinical and radiographic outcomes of computer-navigated total knee arthroplasty are not adversely affected by body mass index

AimTo study the effect of obesity on clinical and radiographic outcomes of computer-navigated knee arthroplasty. Materials and methods117 patients underwent primary computer-navigated total knee arthroplasty. Eight were lost to follow-up and 8 had incomplete data. ResultsEighty-four (83.2%) female, 17 (16.8%) male patients age 65.3 ± 6.9 years with a pre-operative BMI 27.2 ± 4.1 (18.6–40.0) kg/m2, 7.3 ± 0.98 years follow-up. Forty-two (41.6%) had a BMI>27.5 kg/m2 indicative of obesity in Singapore. Post-operative radiographic alignment, 2-year Oxford knee scores and ROM were not significantly associated with BMI. ConclusionBMI is not a determinant of functional scores when computer navigation is used.

A Comparison of Long-Term Outcomes of Computer-Navigated and Conventional Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials.

It is not clear whether long-term outcomes differ between computer-navigated and conventional total knee arthroplasty. The purpose of this study was to perform a meta-analysis comparing the radiographic outcomes, the long-term functional outcomes, and survivorship between computer-navigated total knee arthroplasty and conventional total knee arthroplasty. We searched MEDLINE, Embase, and the Cochrane Library to identify studies comparing long-term outcomes between computer-navigated total knee arthroplasty and conventional total knee arthroplasty. Randomized controlled trials with mean follow-up durations of >8 years were included. The meta-analysis compared radiographic outcomes (postoperative alignment), functional outcomes (range of motion and patient-reported outcomes), and survivorship of the 2 techniques. Nine studies were included. A meta-analysis of accuracy revealed better outcomes in computer-navigated total knee arthroplasty when compared with conventional total knee arthroplasty in terms of the sagittal alignment of the femoral component (risk ratio [RR], 0.69; [95% confidence interval (CI), 0.51 to 0.93]; p = 0.02) and the coronal alignment of the tibial component (RR, 0.75 [95% CI, 0.60 to 0.95]; p = 0.02). The mechanical axis of the lower extremity, the coronal alignment of the femoral component, and the sagittal alignment of the tibial component did not differ significantly between the 2 groups. The functional outcomes did not differ significantly between the 2 techniques. Both in terms of the revision rate and the incidence of aseptic loosening, there were no differences between the 2 techniques. Although computer-navigated total knee arthroplasty resulted in better outcomes in postoperative component alignment than conventional total knee arthroplasty, there were no significant differences in long-term functional outcomes and survivorship between the 2 techniques. To fully evaluate the utility of computer navigation in total knee arthroplasty, additional randomized controlled studies including diverse ethnic groups and countries, as well as studies evaluating the correlation between postoperative alignment and long-term survivorship, are necessary. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Impact of Image-Derived Instrumentation on Total Knee Arthroplasty Revision Rates: An Analysis of 83,823 Procedures from the Australian Orthopaedic Association National Joint Replacement Registry.

Computer navigation and image-derived instrumentation (IDI) are technology-based methods developed to improve outcomes and potentially reduce revision total knee arthroplasty (TKA). IDI refers to the use of manufactured, patient-specific surgical jigs. Conflicting reports exist on IDI-associated improvements in outcomes. The primary aim of the current study was to compare the rates of revision among TKA cases in which components were initially implanted with use of IDI, computer navigation, or neither of these methods ("other" TKA). The secondary aim was to determine whether the outcomes of IDI differed for specific subgroups. Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) for the 3 TKA groups: IDI, computer-navigated, and other TKA. The study period was from the first IDI procedure recorded by the AOANJRR (April 2010) to December 31, 2016. The analysis was restricted to primary TKA cases undertaken for osteoarthritis and involving patellar resurfacing and the use of a cross-linked polyethylene insert. Subanalyses were performed to evaluate the effects of age, sex, implantation method, IDI manufacturer, prosthetic design, and prosthesis type on the rates of revision. Kaplan-Meier estimates of survivorship described the time to first revision. Hazard ratios (HRs, Cox proportional hazards models) with adjustment for age and sex were used to compare revision rates. IDI was used in 5,486 primary TKA procedures. There was no significant difference among the groups in the cumulative percent revision (CPR) at 5 years: 3.3% (95% confidence interval [CI], 2.4% to 4.6%) for IDI, 2.4% (95% CI, 2.2% to 2.7%) for the computer-navigated group, and 2.5% (95% CI, 2.3% to 2.7%) for other TKA. Posterior-stabilized TKA with use of the IDI method had a significantly higher rate of revision at >3 months (HR, 1.45 [95% CI, 1.02 to 2.04]; p = 0.036), as did IDI TKA in the ≤65-year-old patient cohort (HR, 1.52 [95% CI, 1.10 to 2.09]; p = 0.010), compared with computer-navigated TKA. Patellar revision was significantly more likely in the IDI group. IDI TKA demonstrated no overall difference in early to mid-term revision rates compared with standard implantation methods. However, elevated rates of revision were seen with posterior-stabilized TKA, in patients ≤65 years of age, and for patellar revision, meaning that this method should be used with some caution and requires further study. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

No difference in joint awareness after TKA: a matched-pair analysis of a classic implant and its evolutional design.

Total knee arthroplasty (TKA) designs continuously evolve with the aim of improving patient outcomes. The purpose of the current study was to compare clinical and patient-reported outcome (PRO) results of a new TKA implant to its predecessor. The hypothesis of this study was that joint awareness and range of motion (ROM) of the newer design would be better than the classic design. One hundred patients undergoing TKA using the newer design (Attune®) were matched by age and gender to 200 patients with the classic design (LCS®). All patients underwent computer-navigated (Vector Vision, Brain-Lab, Germany) primary TKA by the same surgeon using the same technique. Data (FJS-12, WOMAC and ROM) were collected preoperatively and at 12months follow-up at our implant registry. Compared to preoperative scores, FJS-12, WOMAC and ROM improved significantly at 12months follow-up. In the Attune group, mean FJS-12 and WOMAC at follow-up were 67.6 (SD 27.8) and 14.8 (SD 14.9) respectively, compared to 70.8 (SD 33.8) and 15 (SD 17.9) in the LCS group. Mean postoperative ROM was similar in both groups (Attune 120°, range 90°-140°, SD 10.4 and LCS 120°, range 85°-140°, SD 10.3). The newer TKA and the predecessor design achieved comparable joint awareness, WOMAC scores and ROM at 1-year follow-up. The benefits expected of the newer design could not be observed in early clinical and PROs. The clinical relevance of this study is that it questions the importance of implant design as the single most important factor for patient outcomes. III.

Conventional versus Smart Wireless Navigation in Total Knee Replacement: Similar Outcomes in a Randomized Prospective Study.

Purpose The development of new computer-assisted navigation technologies in total knee arthroplasty (TKA) has attracted great interest; however, the debate remains open as to the real reliability of these systems. We compared conventional TKA with last generation computer-navigated TKA to find out if navigation can reach better radiographic and clinical outcomes. Methods Twenty patients with tricompartmental knee osteoarthritis were prospectively selected for conventional TKA ( n = 10) or last generation computer-navigated TKA ( n = 10). Data regarding age, gender, operated side, and previous surgery were collected. All 20 patients received the same cemented posterior-stabilized TKA. The same surgical instrumentation, including alignment and cutting guides, was used for both the techniques. A single radiologist assessed mechanical alignment and tibial slope before and after surgery. A single orthopaedic surgeon performed clinical evaluation at 1 year after the surgery. Wilcoxon's test was used to compare the outcomes of the two groups. Statistical significance was set at p < 0.05. Results No significant differences in mechanical axis or tibial slope was found between the two groups. The clinical outcome was equally good with both techniques. At a mean follow-up of 15.5 months (range, 13–25 months), all patients from both groups were generally satisfied with a full return to daily activities and without a significance difference between them. Conclusion Our data showed that clinical and radiological outcomes of TKA were not improved by the use of computer-assisted instruments, and that the elevated costs of the system are not warranted. Level of Evidence This is a Level II, randomized clinical trial.

Computed navigated total knee arthroplasty compared to computed tomography scans

BackgroundSuccessful total knee arthroplasty (TKA) includes accurate alignment. Controversy remains as to whether computer-navigated TKA improves the overall result and clinical outcome. Our aim is to compare the limb alignment and prosthesis positioning according to the pre- and postoperative computed tomography (CT) scans with the data collected from the navigation system. MethodsWe compared the pre- and postoperative limb alignments and prosthesis alignment provided by the Orthopilot navigation system, Aesculap®, with CT scans measured by the Traumacad® software of 70 TKAs. ResultsA positive correlation with statistical significance (P=0.00001, r=0.874) between the navigation system data and the CT images was found. Mean femoral cut was five degrees (valgus), and mean tibial cut was one degree (varus). Our study revealed that the navigation system assisted the surgeon to implant the prosthesis at a good acceptable alignment. ConclusionWe found that the navigation system is accurate and correlates to the pre- and postoperative CT scans. Furthermore, the navigation system can assist the surgeon to achieve good limb alignment and cutting planes of the prosthesis.