Accuracy of tibial positioning in the frontal plane: a prospective study comparing conventional and innovative techniques in total knee arthroplasty

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.

Customized-individually-made origin® implants in total knee arthroplasty allow a reliable solution for accurate reproduction of planned implant positioning

PURPOSE

To evaluate the accuracy and reproducibility of a patient-specific, customized individually made (CIM) total knee replacement (TKR) using the ORIGIN® prosthesis.

METHODS

This was a prospective study conducted at a University Hospital from January 15, 2019, to April 30, 2021. The study included patients planned for an ORIGIN® CIM TKR procedure. Exclusion criteria included revision surgery, severe deformity, stiffness, or laxity. Evaluations were carried out using computed tomography scans performed 8 weeks preoperatively and 6 weeks postoperatively. The primary outcome measurements were the preoperative, planned, and postoperative CT scan alignment measurements including the Hip-Knee-Ankle (HKA) angle, mechanical Medial Distal Femoral articular surface Angle (mMDFA, distal alpha angle), Posterior Distal femoral articular surface angle (PDFA, posterior alpha angle), mechanical Medial Proximal Tibial articular surface Angle (mMPTA, beta angle) and posterior proximal tibial angle (PPTA). Secondary outcomes included the accuracy of implant positioning with percentage of outliers at 2° and 3° RESULTS: The study encompassed 51 knees from 50 patients with mean age of 68.1 (SD = 8.89). The overall HKA angle deviated by -0.93° [95% CI: -1.45; -0.43], and the PDFA angle by -0.61° [95% CI: -1.07; -0.15], while the mMPTA exceeded planned values by 1.00° [95% CI: 0.57; 1.43]. The 3° outliers rate ranged from 3.9% for the mMPTA to 7.8% for the HKA alignment, with no outliers in mMDFA and PPTA. Similarly, the 2° outliers rate ranged from 15.7% for both the PDFA angle and mMPTA to 19.6% for the HKA alignment. The Bland-Altman plots further emphasized the precision of planned and post-operative angles across all measurements.

CONCLUSION

The CIM TKR showed high accuracy and reproducibility, closely matching preoperative planning. The weakest accuracy at 3°-outliers is in the reproduction of the HKA alignment at 92.2% (range for all angle: 92.2-100%). Similarly, the weakest accuracy at 2°-outliers is in the reproduction of the HKA alignment at 80.4% (range for all angles: 80.4-92.2%).

Fostering Excellence in Knee Arthroplasty: Developing Optimal Patient Care Pathways and Inspiring Knowledge Transfer of Advanced Surgical Techniques

Osteoarthritis of the knee is common. Early sports trauma or cartilage defects are risk factors for osteoarthritis. If conservative treatment fails, partial or total joint replacement is often performed. A joint replacement aims to restore physiological biomechanics and the quality of life of affected patients. Total knee arthroplasty is one of the most performed surgeries in musculoskeletal medicine. Several developments have taken place over the last decades that have truly altered the way we look at knee arthroplasty today. Some of the fascinating aspects will be presented and discussed in the present narrative review.

Comparison of clinical outcomes of VISIONAIRE patient-specific instrumentation with conventional instrumentation in total knee arthroplasty: a systematic literature review and meta-analysis

INTRODUCTION

Malalignment and resulting complications are major challenges in total knee arthroplasty (TKA) which patient-specific instrumentation (PSI) is proposed to alleviate. Previous PSI meta-analyses of TKA outcomes typically do not differentiate between PSI systems and assess relatively few outcomes, so the value of their findings is limited. VISIONAIRE™ cutting guides (Smith + Nephew Inc., Memphis, TN, USA) is a PSI system based on preoperative magnetic resonance and X-ray imaging. A systematic literature review (SLR) and meta-analysis, focussed specifically on VISIONAIRE, were conducted to assess TKA accuracy, intraoperative outcomes, and postoperative outcomes, compared with conventional instrumentation (CI).

MATERIALS AND METHODS

The SLR was performed using PubMed, Embase, and Google Scholar databases to identify relevant studies published until March 2022. Depending on statistical heterogeneity, meta-analyses were performed for outcome measures with fixed effect (I2 < 50%) or random-effects models (I2 ≥ 50%). Dichotomous outcomes were reported as odds ratios and continuous outcomes were reported as mean differences. Descriptive analyses were performed for outcomes not amenable to meta-analysis.

RESULTS

Outcomes for VISIONAIRE versus CI were reported in 25 studies. Compared with CI, VISIONAIRE reduced odds of mechanical outliers by 40% (p < 0.0001), with no statistically significant differences in odds of overall coronal, sagittal, or rotational plane component outliers. VISIONAIRE improved surgical efficiency (operating room, turnover, and tourniquet times reduced by 7.3% (p = 0.02), 42% (p = 0.022), and 15.9% (p = 0.01), respectively), lowering the odds of blood transfusion by 53% (p = 0.01) and shortening patients' hospital stays (11.1% reduction; p < 0.0001). There were no significant differences between groups in incidence of postoperative complications and (descriptively analyzed) return-to-function outcomes.

CONCLUSION

Options for PSI in TKA differ substantially, and it is important to assess the outcomes of individual systems. The current findings suggest that VISIONAIRE guides can lead to improved alignment accuracy and surgical efficiency compared with CI, without compromising postoperative safety and return-to-function outcomes.

Patient-specific instrumentation in total knee arthroplasty: a review of the current literature

Total knee arthroplasty (TKA) is one of the most frequently performed interventions in the field of Orthopaedic surgery. Over the last decades the implantation technique has improved continuously. The majority of patients is satisfied with the clinical outcome of TKA. However in various clinical follow-ups, up to 20% of unsatisfied patients can be observed. Periprosthetic infection and aseptic loosening seem to be the most common reasons for failure. Malalignment has been discussed as a cause of aseptic loosening and often leads to revision surgery. In order to increase the precision of implant positioning and alignment, new technologies such as patient-specific instrumentation (PSI) have been developed. Since the introduction of PSI, multiple clinical studies have been performed analyzing the clinical and radiological outcome of TKA with PSI technique. This review covers the recent literature of PSI in respect to surgical accuracy, clinical outcome, time- and cost-effectiveness.

Comparison of intramedullary versus extramedullary alignment technique in total knee arthroplasty: A PRISMA-compliant meta-analysis

BACKGROUND

This meta-analysis aimed to compare the efficacy of intramedullary and extramedullary femoral alignment technique in treating total knee arthroplasty (TKA) patients.

METHODS

PubMed, Embase, Cochrane library, Chinese National Knowledge Infrastructure, and Weipu databases were electronically searched. Potential clinical studies that investigated the effect and safety of intramedullary versus extramedullary femoral alignment technique in TKA patients were searched. The primary outcome was lower limb coronal alignment. Stata 12.0 was used for meta-analysis.

RESULTS

This meta-analysis included 12 prospective randomized controlled studies that reported data on 935 TKA patients. No significant difference was noted in lower limb coronal alignment, coronal alignment of femoral component, sagittal alignment of femoral component and tibial slope between intramedullary and extramedullary alignment techniques ( P  > .05). Further, extramedullary alignment technique significantly decrease the total blood loss than intramedullary alignment technique (weighted mean difference: -86.52; 95% confidence interval: -115.05--57.99; P  = .000) and subsequently transfusion rate (risk ratio: 0.57; 95% confidence interval: 0.41-0.79; P  = .000). Finally, there was no significant difference between intramedullary and extramedullary alignment techniques in terms of the total complications ( P  > .05).

CONCLUSIONS

The present meta-analysis showed that intramedullary and extramedullary femoral alignment technique had comparable precise profiles. And extramedullary femoral alignment technique could reduce blood loss and blood transfusion. Total complications were comparable between the groups. More randomized controlled trials with large samples are required to verify the comparison of intramedullary and extramedullary femoral alignment technique in TKA patients.

Increasing grades of frontal deformities in knee osteoarthritis are not associated with ligamentous ankle instabilities

PURPOSE

Varus or valgus deformities in knee osteoarthritis may have a crucial impact on ankle subtalar range of motion (ROM) and ligamentous stability. The purpose of this study was to assess whether the grade of ankle eversion and inversion rotation stability was influenced by frontal deformities of the knee joint.

METHODS

Patients who were planned to undergo total knee arthroplasty (TKA) were prospectively included in this study. Patients were examined radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), anterior distal tibia angle (ADTA)) and clinically (ROM of the knee and ankle joint, foot function index, knee osteoarthritis outcome score). Ankle stability was assessed using an ankle arthrometer (AA) to test inversion/eversion (ie) rotation and anterior/posterior (ap) displacement stability of the ankle joint. Correlations were calculated using Pearson's coefficient, and differences between two independent groups of nonparametric data were calculated using a two-sided Wilcoxon signed rank test.

RESULTS

Eighty-two (varus n = 52, valgus n = 30) patients were included. The preoperative mTFA significantly correlated with the HAVA (Pearson's correlation = - 0.72, p < 0.001). Laxity testing of the ankle demonstrated that in both varus and valgus knee osteoarthritis, higher grades of mTFA did not correlate with the inversion or eversion capacity of the ankle joint. The ADTA significantly correlated with the posterior displacement of the ankle joint (cor = 0.24, p = 0.049).

CONCLUSIONS

This study could not confirm that higher degrees of frontal knee deformities in osteoarthritis were associated with increasing grades of ligamentous ankle instabilities or a reduced ROM of the subtalar joint.

LEVEL OF EVIDENCE

II.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

III.

Accuracy of different navigation systems for femoral and tibial implantation in total knee arthroplasty: a randomised comparative study

PURPOSE

It remains to be established whether optical computed tomography (CT)-free and acceleration-based navigation systems differ in terms of implantation accuracy and clinical outcomes for total knee arthroplasty. This randomised prospective study compared the implantation accuracy of these two navigation systems in total knee arthroplasty.

METHODS

Optical CT-free navigation (ExactechGPS) or acceleration-based navigation (KneeAlign2) was randomly assigned to the left or right knee of 45 patients who underwent a single-stage bilateral total knee arthroplasty: the ExactechGPS (n = 45) and KneeAlign2 groups (n = 45) were compared. Component alignments were evaluated using three-dimensional computed tomography and radiography at pre- and post-surgery. Implantation accuracy of the component alignment, proportion of outliers, postoperative range of motion, and Japanese Orthopaedic Association (JOA) score were compared between the systems.

RESULTS

The implantation accuracies of the lower-extremity mechanical alignment, coronal femoral component angle, coronal tibial component angle, sagittal femoral component, axial femoral angle, and axial tibial angle had no significant difference between the groups. The implantation accuracy of the sagittal tibial component angle was superior in the ExactechGPS than the KneeAlign2 group (1.3° vs. 1.8°, P = 0.034). The proportions of outliers, range of motion, and JOA score had no significant difference between the groups.

CONCLUSION

In the tibial sagittal plane, there was a significant difference in the implantation accuracy, but its difference did not affect the clinical outcomes. Both navigation systems have clinically acceptable implantation accuracy.

Validation and performance of a machine-learning derived prediction guide for total knee arthroplasty component sizing

INTRODUCTION

Anticipation of patient-specific component sizes prior to total knee arthroplasty (TKA) is essential to avoid excessive cost associated with additional surgical trays and morbidity associated with imperfect sizing. Current methods of size prediction, including templating, are inconsistent and time-consuming. Machine learning (ML) algorithms may allow for accurate TKA component size prediction with the ability to make predictions in real-time.

METHODS

Consecutive patients receiving primary TKA between 2012 and 2020 from two large tertiary academic and six community hospitals were identified. The primary outcomes were the final femoral and tibial component sizes extracted from automated inventory systems. Five ML algorithms were trained with routinely corrected demographic variables (age, height, weight, body mass index, and sex) using 80% of the study population and internally validated on an independent set of the remaining 20% of patients. Algorithm performance was evaluated through accuracy, mean absolute error (MAE), and root mean-squared error (RMSE).

RESULTS

A total of 17,283 patients that received one of 9 TKA implants from independent manufacturers were included. The SGB model accuracy for predicting ± 4-mm of the true femoral anteroposterior diameter was 83.6% and for ± 1 size of the true femoral component size was 95.0%. The SGB model accuracy for predicting ± 4-mm of the true tibial medial/lateral diameter was 83.0% and for ± 1 size of the true tibial component size was 97.8%. Patient sex was the most influential feature in terms of informing the SGB model predictions for both femoral and tibial component sizing. A TKA implant sizing application was subsequently created.

CONCLUSION

Novel machine learning algorithms demonstrated good to excellent performance for predicting TKA component size. Patient sex appears to contribute an important role in predicting TKA size. A web-based real-time prediction application was created capable of integrating patient specific data to predict TKA size, which will require external validation prior to clinical use.

Handheld computer-navigated constrained total knee arthroplasty for complex extra-articular deformities

INTRODUCTION

The present study aimed to assess the postoperative alignment and clinical outcomes of patients with complex extra-articular deformities (EADs) undergoing computer-assisted surgery (CAS) for constrained total knee arthroplasty (TKA) with modular stem extensions.

MATERIALS AND METHODS

From May 2015 to July 2018, ten patients with EADs scheduled for constrained TKA were enrolled retrospectively. The preoperative average deviation from neutral (= 180°) mechanical axis was 15.3° (range of coronal alignment: 150.9° varus-202.9° valgus). Alignment was assessed using an accelerometer-based handheld CAS system. On long-leg films, the positions of the components and possible stems were analysed and templated preoperatively. The average follow-up was 3.3 years (range: 2.0-4.6 years).

RESULTS

The postoperative mechanical axis was within ± 3.0° from neutral in nine patients. In all patients, the Knee Society score (KSS) and range of motion improved significantly. A constrained condylar and a rotating hinge prosthesis were used in five patients each. In eight patients, the 100-mm cementless stem that was preferred by the authors was found to be unusable for the femur or the tibia in the planning stage. For the femur, a cementless 100-mm stem was used in three, and a cemented 30-mm stem in five patients; a femoral stem was not usable in two patients. For the tibia, a cementless 100-mm stem was used in six, and a cemented 30-mm stem in two patients; a monoblock rotating hinge tibia was used in two patients.

CONCLUSIONS

Complex EADs were excellently managed during constrained TKA implantation using the handheld CAS system. Templating allowed the possible stem lengths to be identified and prevented anatomical conflict with the CAS-configured mechanical alignment. Limb alignment and function improved significantly after surgery. No intra- or postoperative complications occurred.

LEVEL OF EVIDENCE

Level IV, retrospective study.

[Research progress on comparison of the application effects between personal specific instrumentation and computer-assisted navigation surgery in total knee arthroplasty]

OBJECTIVE

To compare the application effects between personal specific instrumentation (PSI) and computer-assisted navigation surgery (CAS) in total knee arthroplasty (TKA).

METHODS

The literature comparing the application effects of PSI and CAS in TKA in recent years was widely consulted, and the difference between PSI-TKA and CAS-TKA in operation time, lower limb alignment, blood loss, and knee function were compared.

RESULTS

Compared to CAS-TKA, PSI-TKA simplifies operation procedures and shortens operation time but probably has worse lower limb alignment. It is still controversial in comparison of perioperative blood loss and knee function between two techniques.

CONCLUSION

PSI-TKA and CAS-TKA both have advantages and disadvantages, and their differences need to be confirmed by further high-quality clinical trial.

Customised, individually made total knee arthroplasty shows promising 1-year clinical and patient reported outcomes

INTRODUCTION

Customised individually made (CIM) implants for total knee arthroplasty (TKA) were introduced about 10 years ago. These implants aim to reduce the risk of prosthesis-related issues resulting from anthropometric differences between different knees. The purpose of this study was to analyse the short-term clinical outcome and patient reported outcome measures (PROMs) of a specific CIM implant, the ORIGIN^® knee replacement system (Symbios, Yverdon-les-Bains, Switzerland), which was introduced in 2018.

MATERIALS AND METHODS

This is a prospective cohort study of patients undergoing primary posterior-stabilised (PS) CIM TKA using the specific ORIGIN^® knee replacement system, (Symbios, Yverdon-les-Bains, Switzerland). TKAs were performed from February 2019 to October 2020. Data was collected preoperatively and postoperatively at 4 and 12 months. Outcome measures included the objective part of the Knee Society Score (KSS) with the range of motion (ROM) and the following PROMs: the Knee injury and Osteoarthritis Outcome Score (KOOS), the Forgotten Joint Score (FJS-12), the EuroQol, five dimensions, three levels (EQ-5D-3L) with the EuroQol visual analogue scale (EQ-VAS) and patient satisfaction. Differences in pre- to preoperative data were assessed with paired sample t tests. A p value < 0.05 was considered significant.

RESULTS

Twenty-five CIM TKA (20 patients, 8 female) were included. The mean age at surgery was 66 years (SD, 6.9). At 4 and 12 months, significant improvements in the KSS (p < 0.001), the ROM (p < 0.001), all KOOS subscales (p < 0.001), the FJS (p < 0.001) and the EQ-5D-3L (p < 0.026) were found. Satisfaction rate was 91% and 88% at 4 and 12 months, respectively. Intraoperative complications did not occur and no revision surgeries were undertaken.

CONCLUSIONS

The present study demonstrated significant improvements in the KSS and specific PROMs 1 year after CIM TKA. This study suggests that CIM TKA is a safe and suitable option, which can yield good clinical outcome and PROMs at least during short-term follow-up.