A Systematic Literature Review of Three Modalities in Technologically Assisted TKA

The use of accelerometer-based navigation for coronal TKA alignment: a prospective, single surgeon comparative study

INTRODUCTION

There is the need for a device that can be used to accurately position components during total knee arthroplasty (TKA) with minimal impact on procedure time, workflow and cost. This study aimed to investigate the accuracy and time efficiency of a novel, accelerometer-based navigation system (ABN).

METHODS

This prospective, single surgeon study of patients undergoing TKA for osteoarthritis over a 5 year period involved a total of 138 patients: 110 using the ABN system and 28 without. The ABN system consists of two coupled inertial pods that are secured to resection guides, providing a body-fixed 3D coordinate system for limb segments. Post-operative coronal alignment was measured from standardised long-leg AP radiographs. Deviation of the femur and tibia from the neutral coronal mechanical axis was recorded. Intra-observer repeatability was performed on three independent blinded data sets. The BMI and the surgical time (skin to skin) were recorded for all patients.

RESULTS

The mean BMI was 34 in the ABN group and 33 in the control group (p = 0.92). The skin-to-skin time was also similar between the groups; 105 min in the navigation group and 100 min in the control group (p = 0.297). The use of navigation resulted in significantly fewer outliers as defined by < 3º deviation from the target angle. 3 of 110 navigated patients recorded an AP femur angle of more than 3º from the target of 90º, where 5 of 28 control patients fell outside of the ± 3º window (p = 0.009, Fig. 1).

CONCLUSION

The use of the ABN system significantly improved accuracy of implant position and alignment without increasing surgical time.

Kellgren-Lawrence grade of osteoarthritis is associated with change in certain morphological parameters

BACKGROUND

To compare selected morphological parameters between normal and osteoarthritic (OA) knees, as well as to evaluate differences in these parameters between Kellgren-Lawrence (K-L) grades of OA.

METHODS

Knee joint morphology was evaluated using magnetic resonance (MR) images of 200 participants with knee OA (50 each of K-L grades 1-4) and 50 without knee OA, matched for age, body mass index, sex, and tibiofemoral angle. Knees with a coronal alignment within five degrees of neutral and no apparent bone loss on radiographs were included. Twenty-one morphologic parameters of the distal femur and proximal tibia were measured on MR images. Correlation between the K-L grade and measured parameters and differences in measured parameters across the K-L grades and between the OA and control groups were evaluated.

RESULTS

The K-L grade was significantly correlated with multiple distal femur measurements including the posterior condylar angle (PCA), lateral epicondyle to posterior condylar cartilage (LEPC) length, medial epicondyle to posterior condylar cartilage (MEPC) length, medial epicondyle to distal cartilage (MEDC) length, medial tibial slope angle, femoral condylar cartilage height difference (FCHDc), and femoral condylar bone height difference (FCHDb) (P < 0.05). A significant difference was identified between the different K-L grades with regard to PCA, LEPC, MEPC, MEDC, and FCHDc (P < 0.05). There was no correlation between K-L grade and measured proximal tibial parameters.

CONCLUSIONS

Among knees without significant angular deformity, progression of knee OA is associated with a change in the morphology of the femoral condyles but not of the proximal tibia.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early outcomes of patient-specific posterior stabilized total knee arthroplasty implants

Patient-specific implants have been linked to stiffness. The purpose of this study was to evaluate outcomes in patient-specific implants. We performed a retrospective review with a primary outcome of manipulation under anesthesia (MUA); secondary outcomes included Knee Society Scores (KSS), Knee Society Functional Scores (KSFS), range of motion (ROM), and Forgotten Joint Scores (FJS). Pre-operative measurements were similar in both groups. There was one MUA in the CPS and two in the OTS groups. There was no difference in postoperative scores. Our study suggests patient-specific implants have comparable rates of MUA and functional outcomes as conventional implants.

Advances in Computer-Aided Technology for Total Knee Arthroplasty

Technology such as computer-assisted navigation systems, robotic-assisted systems, and patient-specific instrumentation has been increasingly explored during the past decade in an effort to optimize component alignment and improve clinical outcomes. Computer-assisted navigation accurately restores mechanical-axis alignment, but clinical outcome data are inconsistent. Computer-assisted navigation gap balancing has shown early promise in establishing mechanical-axis alignment with improved functional outcomes. Robotic-assisted systems more accurately restore component alignment when compared with computer-assisted navigation, but clinical outcomes have yet to be determined. Patient-specific instrumentation does not consistently improve alignment, accuracy, or patient outcomes. Studies demonstrating implant survivorship, cost-efficiency, and improved clinical outcomes and patient satisfaction are needed. [Orthopedics. 2017; 40(6):338-352.].