Accelerometer-Based Portable Navigation System Is Useful for Tibial Bone Cutting in Modified Kinematically Aligned Total Knee Arthroplasty

Limitations of the knee society score in kinematically aligned total knee arthroplasty

Purpose

The Knee Society Scoring System (KSS) is a frequently used outcome score which quantifies functional patients' outcomes before and after total knee arthroplasty (TKA). Several problems arise when trying to implement KSS for obtaining postoperative outcomes after more personalised aligned TKAs. Scoring for valgus femorotibial angle (FTA) intervals outside moderate ranges is often poorly explained, the specific version of KSS used for outcome collection is frequently unclear and the exact measuring methods are typically not described in the literature. The aims of this systematic review were to investigate the latest user practice, the application of KSS and its limitations after kinematically aligned (KA) TKA.

Methods

A systematic literature search following PRISMA guidelines was conducted on PubMed, Embase, Medline and Scopus to identify potentially relevant articles for this review, published from the beginning of January 2013 until the end of January 2023. Broad Mesh terms such as 'kinematic alignment', 'total knee arthroplasty' and 'knee society score' were used for building search strategy in each database accordingly. Articles reporting postoperative values of the objective surgeon-assessed KSS after KA TKA or KA and mechanically aligned TKA were included. For assessing included randomised control trials (RCTs), an Agency for Healthcare Research and Quality's design-specific scale for assessing RCTs was used. The non-RCTs were assessed by using the Joanna Briggs Institute Critical Appraisal Tool. The Ottawa-Newcastle Score system was also used. Studies were additionally evaluated for their radiological methodology by using a five-question checklist (Radiological Assessment Qualit criteria).

Results

The initial search identified 167 studies, of which 129 were considered for screening. Ten studies reporting outcomes after KA TKA did not use the objective surgeon-assessed part of KSS for clinical outcome measurement, and 30 studies reporting outcomes after KA TKA did not use KSS at all for clinical and/or functional outcomes. From the 10 included studies, only six have used the latest KSS score (2011), the rest using its 1989 variant; and out of these six studies, only two presented values of the FTA, which is needed for calculating the KSS's 'alignment' subcomponent, the rest presenting hip-knee-ankle angle (HKA) values. Additionally, when converting these HKA values to FTA intervals, the authors of this systematic review found that KA TKA FTA intervals display limits, which tend to be outside the 'well-scored' KSS anatomical alignment interval.

Conclusion

The inconsistent and nonstandardised use of the surgeon-assessed KSS across studies reviewed compromises assessment reliability and patient outcome scores. To enhance precision and comparability, it is crucial to standardise the KSS application, incorporating personalised alignment strategies for more accurate patient evaluations.

Level of Evidence

Level III.

No difference in postoperative patient satisfaction rates between mechanical and kinematic alignment total knee arthroplasty: A systematic review

Purpose

The purpose of this systematic review was to compare patient satisfaction patient-reported outcomes (PROMs) levels after mechanically aligned (MA) and kinematically aligned (KA) total knee arthroplasty (TKA).

Methods

A systematic literature search following PRISMA guidelines was conducted on PubMed, Embase, Medline and Scopus to identify potentially relevant articles for this review, published from the beginning of March 2013 until the end of October 2023. Only articles reporting satisfaction after KA TKA, MA TKA or both were included, which use valid and reliable tools for the evaluation and reporting of satisfaction after TKA. Title, authors, year of publication, study design, level of evidence, follow-up period, patients' demographic data, sample size, type of satisfaction score, postoperative satisfaction score, postoperative alignment, statistical significance, as well as other variables, were extracted for analysis. An Agency for Healthcare Research and Quality's (AHRQ) design-specific scale was used for assessing randomized control trials (RCTs). The nonrandomized control trials were evaluated by using the Joanna Briggs Institute's (JBI) Critical Appraisal Tool. The Newcastle-Ottawa Scale (NOS) was also used to assess cohort studies, while case series were evaluated using the NIH Quality Assessment Tool for Case Series Studies.

Results

The initial search identified 316 studies, of which 178 were considered for screening. Eleven studies completely fulfilled the inclusion criteria, including one RCT, five nonrandomized control trials/quasi-experiments, three case series, and two cohort studies. The total number of patients recruited for MA TKA was 1740. Conversely, 497 patients were enrolled for KA TKA. Five studies used the visual analogue scale (VAS) for assessing postoperative patient satisfaction, four used the Knee Society Score (KSS) 2011 version and two Likert-based types of scores. Overall, the highest mean satisfaction score of KSS 2011 was 31.5 ± 6.6 in the MA group, and 29.8 ± 80 in the KA group in four studies. All of them showed high postoperative patient satisfaction rates for both MA and KA TKA, but with no statistically significant difference between them (p > 0.05).

Conclusion

Both mechanically aligned total knee arthroplasty, as well as kinematically aligned total knee arthroplasty led to high rates of postoperative patient satisfaction, with no statistically significant differences between them.

Level of Evidence

Level III, systematic review.

Superiority of kinematic alignment over mechanical alignment in total knee arthroplasty during medium- to long-term follow-up: A meta-analysis and trial sequential analysis

PURPOSE

To compare and determine the reliability and conclusiveness of the medium- and long-term efficacy in terms of patient-reported outcome measures and the risk of revisions or reoperations (RRRs) of kinematic alignment (KA) and mechanical alignment (MA) in total knee arthroplasty.

METHODS

A comprehensive search was conducted in Medline, EMBASE, Web of Science and Cochrane Database Library to identify relevant literature. Only randomised clinical trials (RCTs) published before July 2023 were included. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford Knee Score (OKS), Forgotten Joint Score (FJS) and RRR were compared. Additionally, OKS and RRR were subjected to a trial sequential analysis.

RESULTS

Seven RCTs involving 572 knees were identified. The pooled analysis of the included studies demonstrated that KA showed better medium-term WOMAC and OKS (mean difference [MD] = -6.3, 95% confidence interval [CI]: -9.52 to -2.99, p < 0.05 and MD = 1.1, 95% CI: 0.05-2.15, p < 0.05), respectively), but no significant differences were observed in the long-term follow-up (MD = 2.1, 95% CI: -3.21 to 7.31, not significant [n.s.] and MD = 0.01, 95% CI: -2.43 to 2.46, n.s., respectively). FJS (standardised MD = -0.03, 95% CI: -0.25 to 0.19, n.s.) and RRR (risk ratio = 1.0, 95% CI: 0.57 to 1.74, n.s.) showed no significant intergroup differences (n.s.). The evidence quality ranged from moderate to high, and the trial sequential analysis indicated the need for additional high-quality RCTs to draw more conclusive results.

CONCLUSIONS

KA showed better medium-term WOMAC and OKS, while KA and MA had similar FJS without increasing the RRR in medium- and long-term follow-up. Further research is needed for more conclusive results.

LEVEL OF EVIDENCE

Level II (meta-analyses).

The Accuracy of a Portable Accelerometer-Based Navigation System for Tibial Alignment Can be Reliable during Total Knee Arthroplasty for Obese Patients

A portable accelerometer-based navigation system can be useful for achieving the target alignment. Tibial registration is based on the medial and lateral malleoli; however, the identification of landmarks may be difficult in obese (body mass index [BMI] >30 kg/m2) patients whose bones are not easily palpable from the body surface. This study compared tibial component alignment achieved using a portable accelerometer-based navigation system (Knee Align 2 [KA2]) in obese and control groups and aimed to validate the accuracy of bone cutting in obese patients. A total of 210 knees that underwent primary total knee arthroplasty using the KA2 system were included. After 1:3 propensity score matching, there were 32 and 96 knees in the BMI >30 group (group O) and BMI ≤30 group (group C), respectively. The absolute deviations of the tibial implant from the intended alignment were evaluated in the coronal plane (hip-knee-ankle [HKA] angle and medial proximal tibial angle) and sagittal plane (posterior tibial slope [PTS]). The inlier rate of each cohort, which was defined as tibial component alignment within 2 degrees of the intended alignment, was investigated. In the coronal plane, the absolute deviations of the HKA and MPTA from the intended alignment were 2.2 ± 1.8 degrees and 1.8 ± 1.5 degrees in group C and 1.7 ± 1.5 degrees and 1.7 ± 1.0 degrees in group O (p = 1.26, and p = 0.532). In the sagittal plane, the absolute deviations of the tibial implant were 1.6 ± 1.2 degrees in group C and 1.5 ± 1.1 degrees in group O (p = 0.570). The inlier rate was not significantly different between group C and group O (HKA: 64.6 vs. 71.9%, p = 0.521; MPTA: 67.7 vs. 78.1%, p = 0.372; PTS: 82.2 vs. 77.8%, p = 0.667). The accuracy of tibial bone cutting for the obese group was comparable to that of the control group. An accelerometer-based portable navigation system can be useful when attempting to achieve the target tibial alignment in obese patients. LEVEL OF EVIDENCE:  Level IV.

An updated meta-analysis comparing complications, functional, clinically relevant and radiological outcomes of accelerometer based portable navigation and conventional technique of total knee arthroplasty

Introduction

Since previous studies, including small-scale meta-analyses comparing accelerometer-based portable navigation (APN-TKA) and conventional techniqueof total knee arthroplasty (CONV-TKA), have reported divergent results, there is a need for an updated meta-analysis to compare complications, functional outcomes, clinically relevant outcomes and radiographic alignment of components.

Methods

This meta-analysis was conducted as per PRISMA guidelines. Randomised controlled trials, and non-randomised comparative cohort studies in English language on primary TKA were included. The complications compared were Deep Vein Thrombosis (DVT), Pulmonary Embolism (PE), infection, manipulation under anaesthesia (MUA) for postoperative knee stiffness, re-operation and mortality. The functional outcomes compared were the Knee Society Knee Score, Knee Society Score function, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score and Western Ontario and McMaster Universities Arthritis Index. The evaluated clinically relevant outcomes were surgical time, blood loss, drop in haematocrit, tourniquet time, postoperative knee flexion and complications). The number of radiological outliers; as well as the absolute values of the alignment of the overall prosthesis, femoral and tibial components in both coronal and sagittal planes, was assessed.

Results

Twenty-five studies were included. Both the groups were comparable in terms of preoperative demographic features. There was no difference in complications and functional outcomes. Operation time was longer in APN-TKA (p < 0.00001) but there was no difference in rest of the clinically relevant outcomes. Restoration of the lower limb mechanical axis (p = 0.003) and coronal femoral alignment angle (p = 0.0002) was better with APN. APN also significantly reduced the risk of the odds of outliers of lower limb mechanical axis (p < 0.0001), coronal femoral alignment (p = 0.03), coronal tibial alignment (p < 0.0001) and sagittal tibial alignment (p = 0.0001).

Conclusion

The improvement in the accuracy of implantation by the use of APN-TKA, as determined by the overall alignments of prosthesis, or femoral and tibial components, does not necessarily translate into lesser complications and better functional and clinical outcomes.

Level of evidence

Therapeutic study, Level II.

Effects of Femoral Component Design on the Deepest Point Position of the Trochlear Grove in Kinematically Aligned Total Knee Arthroplasty: A Comparison of Four Prothesis Designs

The aim of the study is to explore and compare the differences in trochlear shape and knee anatomy between four types of prostheses and preoperative native knee matched with preoperative computed tomography (CT). Thirty patients were scheduled for primary kinematically aligned total knee arthroplasty (TKA) for varus knee osteoarthritis at our hospital and the region between their pelvis to ankle joint was simulated using a CT-based three-dimensional planning software. The axial plane containing the transepicondylar axis was set as Slice A, and the 10-mm distal plane from Slice A was set as Slice B. The distances to the deepest trochlear groove between the native knee and each prosthesis and the medial and lateral facet heights were compared among the four groups. The deepest femoral trochlear groove of the prostheses was located 1.6 to 3.0 mm more medial than that of the native knee, and in the Persona group, it was significantly more medial than in the e-motion or Triathlon groups on both Slices A and B. The native knee and the medial and lateral facet heights of the four prostheses on both Slices A and B were significantly lower than those of preoperative native knees when femoral prostheses were set in the kinematically aligned (KA)-TKA position. The deepest point of the trochlear groove of the Persona group was the most medial among the four prostheses studied, and the deepest points differed depending on the prosthesis design in KA-TKA. Thus, surgeons should carefully select the type of prostheses used in KA-TKA.

Comparison of navigation systems for total knee arthroplasty: A systematic review and meta-analysis

Background

Component alignment is a crucial factor affecting the clinical outcome of total knee arthroplasty (TKA). Accelerometer-based navigation (ABN) systems were developed to improve the accuracy of alignment during surgery. This study aimed to compare differences in component alignment, clinical outcomes, and surgical duration when using conventional instrumentation (CONI), ABN, and computer navigation (CN) systems.

Methods

A comprehensive literature search was carried out using the Web of Science, Embase, PubMed, and Cochrane databases. Articles that met the eligibility criteria were included in the study. Meta-analyses were performed using the Cochrane Collaboration Review Manager based on Cochrane Review Method. The variables used for the analyses were postoperative clinical outcome (PCO), surgical duration, and component alignment, including the hip-knee-ankle (HKA) angle, coronal femoral angle (CFA), coronal tibial angle (CTA), sagittal femoral angle (SFA), sagittal tibial angle (STA), and the outliers for the mentioned angles. The mean difference (MD) was calculated to determine the difference between the surgical techniques for continuous variables and the odds ratio (OR) was used for the dichotomous outcomes.

Results

The meta-analysis of the CONI and ABN system included 18 studies involving 2,070 TKA procedures, while the comparison of the ABN and CN systems included 5 studies involving 478 TKA procedures. The results showed that the ABN system provided more accurate component alignment for HKA, CFA, CTA, and SFA and produced fewer outliers for HKA, CFA, CTA, and STA. However, while the ABN system also required a significantly longer surgical time than the CONI approach, there was no statistical difference in PCO for the two systems. For the ABN and CN systems, there was no statistical difference in all variables except for the ABN system having a significantly shorter surgical duration.

Conclusion

There was no significant difference in the accuracy of component alignment between the ABN and CN systems, but the ABN approach had a shorter surgical duration and at lower cost. The ABN system also significantly improved the accuracy of component alignment when compared to the CONI approach, although the surgery was longer. However, there was no significant difference in PCO between the CONI, ABN, and CN systems.

Robust Randomized Controlled Data Is Lacking in Total Joint Arthroplasty

INTRODUCTION

 Randomized controlled trials (RCTs)are regarded as highest level of scientific evidence. There is belief that while prospective randomized control trials (PRCTs) are the gold standard for evaluating efficacy of interventions, there are very few conducted on lower extremity joint arthroplasty. However, there was a more than adequate amount (n=197) of published RCTs in knee arthroplasty during the 2021 calendar year. Therefore, we studied RCTs on knee arthroplasties for 2021 and assessed them for overall study topic reasons (i.e., devices as well as prostheses, rehabilitation, pain control, blood loss [tranexamic acid], and other), which were then subcategorized by: (1) country of origin; (2) sample size; and (3)whether or not they were follow-up studies. After this, we specifically focused on the studies (n=26) concerning devices or prostheses.

METHODS

 A search of PubMed on "knee arthroplasty" specifying "RCT" using their search function and dates between January 1, 2021 to December 24, 2021 resulted in the analyzed reports. A total of 17.3% reports analyzed rehabilitation methods while 28.4% studied pain control. A total of 20.3% examined blood loss topics and 20.8% investigated other topics.

RESULTS

 We found that 26 studies (13.2%) involved prosthetic design and implantation. Overall, only 15% knee arthroplasty RCTs were conducted in the United States, the mean total final sample size was 133±146 patients, and 7% were follow-up studies. None of the prostheses studies were performed in the United States, and the mean total final sample size of all of these studies was 86±54 patients, and 23% were follow-up studies. Total knee arthroplasty prospective RCTs were not performed in the United States.

CONCLUSION

 The authors believe that other study designs, such as database or registry analyses, are also appropriate in this rapidly advancing field of joint arthroplasty for the continuing evaluation and approval of new prostheses and techniques, while we await more PRCTs in our field.

Preoperative uncorrectable tibiofemoral subluxation can worsen clinical outcomes after fixed-bearing unicompartmental knee arthroplasty: a retrospective analysis

INTRODUCTION

The presence of tibiofemoral subluxation (TFS) in patients with unicompartmental arthritis, a potential contraindication to unicompartmental knee arthroplasty (UKA), remains controversial and is not commonly discussed. This study aimed to determine the predictability of postoperative TFS before surgery and the effect of TFS on clinical outcomes after fixed-bearing UKA.

MATERIALS AND METHODS

In total, 70 patients with anteromedial osteoarthritis and osteonecrosis of the knee who underwent fixed-bearing UKA from January 2015 to January 2017 were included. The preoperative TFS was assessed using plain anteroposterior and valgus stress radiographs. The patients were classified into three groups as follows: group A (acceptable TFS, n = 36) comprising patients with preoperative TFS less than 5.0 mm; group C (correctable TFS, n = 17) comprising patients with preoperative TFS of more than 5.0 mm but corrected to less than 5.0 mm under valgus stress; and group U (uncorrectable TFS, n = 17) comprising patients with preoperative TFS of more than 5.0 mm under valgus stress. Patient-derived clinical scores were assessed with the 2011 Knee Society Score preoperatively and 2 years postoperatively. The results were compared among the three groups using analysis of variance.

RESULTS

Group U showed significantly higher postoperative TFS than groups A and C. Improvements in "symptoms" and "patient satisfaction" scores 2 years after surgery were significantly higher in groups A and C than in group U.

CONCLUSION

Preoperative assessment of TFS under valgus stress could be a predictor of postoperative TFS. Furthermore, preoperative uncorrectable TFS could increase pain and decrease patient satisfaction 2 years after undergoing fixed-bearing UKA.

The Effect of Prosthesis Type on Intraoperative Soft-Tissue Balance and Clinical Outcomes in Modified Kinematically Aligned Cruciate-Retaining Total Knee Arthroplasty

INTRODUCTION

 Kinematically aligned total knee arthroplasty (KA-TKA) has gained interest for achieving more favorable clinical outcomes than mechanically aligned TKA. One of the advantages of KA-TKA is reported to be an easy acquisition of intraoperative soft-tissue balance without excessive medial release for varus osteoarthritis. However, we hypothesized that the prosthesis type affects intraoperative soft-tissue balance even in the KA-TKA. The present study aimed to compare intraoperative soft-tissue balance and clinical outcomes of KA-TKAs using single-radius (SR) or multiradius (MR) prostheses.

MATERIALS

 AND METHODS: Consecutive 70 cruciate-retaining modified KA-TKAs (31 SR and 39 MR) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative soft-tissue balance including joint component gap and varus/valgus balance was measured with femoral component placement and patellofemoral joint reduction throughout the range of motion using offset-type tensor and compared between the two groups. Two years postoperatively, the range of motion and 2011 Knee Society Scores were compared between the two groups.

RESULTS AND CONCLUSION

 Joint component gaps showed no significant differences between the two groups from 0 to 30 degrees of flexion. However, during 60 to 120 degrees of flexion, joint component gaps of SR group showed significantly larger values than those of MR group (p < 0.05). There were no significant differences in varus/valgus balance throughout the range of motion between the two groups. The postoperative clinical outcomes showed no significant differences between the two groups.

INTERPRETATION

 Despite no difference in clinical outcomes, joint component gap showed different patterns due to the prosthesis type in modified KA-TKAs.

Comparison between Single- and Multi-Radius Prostheses Used in Modified Kinematically Aligned Cruciate-Retaining Total Knee Arthroplasty

Kinematically aligned total knee arthroplasty (TKA) has gained interest for achieving more favorable clinical outcomes than mechanically aligned TKA. The present study aimed to compare the clinical outcomes of kinematically aligned TKAs using single-radius (SR) or multi-radius (MR) prostheses. Sixty modified kinematically aligned cruciate-retaining TKAs (30 SR and 30 MR type prostheses) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative and postoperative patellar tracking were compared between the two groups. Trochlea shape was also compared between the prostheses and preoperative native anatomy using three-dimensional simulation software. Total 2 years postoperatively, the range of motion and 2011 Knee Society Scores (KSS) were compared between the two groups. There were no differences in patellar maltracking including patellar lateral shift and tilt between the two groups; however, the ratio of intraoperative lateral retinacular release for adjusting patellar tracking was significantly higher in the MR group than in the SR group. Lateral and medial facet heights in both prostheses were understuffed compared with native knee anatomy, while the deepest point of the trochlear groove was significantly more medial in the MR group. The postoperative clinical outcomes showed no significant differences between the two groups. In conclusion, modified kinematically aligned TKAs using a SR or MR prosthesis showed no significant differences in clinical outcomes or patellar tracking when appropriate lateral retinacular release was performed.

Comparison of clinical and biomechanical outcomes between the kinematic and mechanical alignment methods in total knee arthroplasty: Protocol for a multicenter randomized controlled trial

Introduction

The concept of anatomic restoration has garnered considerable interest in the form of kinematically aligned total knee arthroplasty (KA-TKA). KA-TKAs have been reported to reproduce natural alignment and kinematics. However, few randomized controlled trials (RCTs) have compared the biomechanical outcomes and the long-term clinical outcomes of KA-TKA with those of mechanically aligned TKA (MA-TKA). We aim to investigate the long-term clinical and biomechanical effects of KA-TKA and to determine whether KA-TKA or MA-TKA is more appropriate for primary TKA.

Methods

This trial will compare clinical and biomechanical outcomes of KA-TKA to those of MA-TKA. Two hundred patients will be enrolled in the RCT and randomized into KA-TKA or MA-TKA groups. Both the groups will be evaluated 1 week before the operation, on the day of the operation, 6 months after the operation, and 1, 5, and 10 years after the operation. The primary outcome is the difference between preoperative and 1-year postoperative functional activity scores of the 2011 Knee Society Score (2011 KSS) in both groups as well as the differences between the scores of both groups. The secondary outcomes will include differences in symptom, satisfaction, and expectation scores of the 2011 KSS, intraoperative kinematics evaluation, postoperative clinical outcomes and complications, pre- and postoperative gait analyses and radiograph evaluations between both KA-TKA and MA-TKA.

Current evidence base for kinematic alignment

BACKGROUND

Kinematic alignment recently became an alternative alignment option for total knee arthroplasty (TKA). Beside previous studies assessing mechanical alignment in comparison to unintentional malalignment of TKA in terms of implant survival and clinical outcome, more and more studies have focused on the direct comparison of intentional kinematic alignment with mechanical alignment of the prosthesis. In the past 5 years the number of studies with respect to kinematic alignment has risen from 11 to 91 studies.

AIM

The aim of this review article is to give a narrative overview of the current literature in the debate concerning kinematic and mechanical alignment in TKA.