Alignment options and robotics in total knee arthroplasty

Kinematic Alignment Technique Outperforms Mechanical Alignment in Simultaneous Bilateral Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

The aim of this study was to compare the clinical results of kinematic alignment (KA) with those of mechanical alignment (MA) in single-stage bilateral total knee arthroplasty.

METHODS

In this double-blinded randomized controlled trial, 65 patients who had bilateral knee osteoarthritis underwent simultaneous bilateral total knee arthroplasty. One knee was randomly selected to be operated on with the calipered-KA technique and the other with MA. The participants were assessed via the Oxford Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index questionnaire, and visual analog scale before the surgery and the same plus the Forgotten Joint Score at their last follow-up visit, 2 years postoperatively. Maximum knee flexion and the time reaching maximum knee flexion, named the recovery time, were also recorded. Hip-knee-ankle angle, medial proximal tibial angle, and lateral distal femoral angle were measured before and after the surgery using 3-joint-view radiographs.

RESULTS

At 2 years, there were significant differences between the KA and MA techniques in terms of duration of surgery, recovery time, and final Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and maximum flexion range in favor of KA (P < .05), but no significant difference in visual analog scale score or Oxford Knee Score. In patients who have a preferred knee, the KA knee was preferred over the MA knee by most patients. No prosthetic failure or revision was reported in either group.

CONCLUSIONS

The KA technique yields acceptable functional outcomes compared to the MA technique. The KA technique was associated with a shorter surgery time, a faster recovery time, and higher patient satisfaction in 2-year follow-ups. Larger multicenter studies with longer follow-ups are warranted to confirm these findings.

LEVEL OF EVIDENCE

I.

Evaluation of the External Rotation of the Femur Component in Functionally Aligned Robotic-Assisted Total Knee Arthroplasty

Background The conventional total knee arthroplasty (TKA) for grade 4 knee arthritis lacks individualized strategies for determining femur component rotation, contributing to suboptimal clinical outcomes and heightened patient dissatisfaction. Methods One hundred consecutive active robotic-assisted TKA (RA-TKA) patients were retrospectively evaluated. The control group is the patients undergoing conventional TKA for grade 4 arthritis of the knee joint, where the femoral component is placed in a fixed 3-degree external rotation. The study aimed to explore the relationships between the posterior femoral axis of the functionally aligned TKA (FAA), the trans-epicondylar axis (TEA), and the posterior condylar axis (PCA). Specifically, it investigated whether there is a statistically significant difference in femoral component rotation between the functionally aligned TKA (FTKA) and the conventional 3-degrees of external rotation of the femoral component used in traditional TKA (C-TKA). Internal rotation is indicated by a negative value for the femur component. A student's t-test was employed to compare mean rotation values between FTKA and C-TKA, with a p-value below 0.05 considered statistically significant. Results A total of 100 patients (male: female, 11:89) were studied. The FAA was externally rotated in relation to the TEA (mean 1.451°, SD 1.023°, p-value <0.0001). As regards the PCA, the FAA was externally rotated (mean 2.36°, SD 2.221°, p-value 0.0002). These findings demonstrate a statistically significant difference in femoral component rotation between FTKA and C-TKA. Clinically, no patellofemoral complications or premature loosening were observed at one-year follow-up. Conclusion Functional alignment TKA technique resulted in external rotation of the femur component with respect to TEA and PCA. This negates the null hypothesis, indicating a statistically significant difference amongst the femur component rotation implanted according to the FTKA concept with robotic assisted technology and C-TKA.

Navigating the Divide: A Comprehensive Review of the Mechanical and Anatomical Axis Approaches in Total Knee Replacement

This comprehensive review explores the mechanical and anatomical axis approaches in total knee replacement (TKR) surgery, addressing the ongoing debate within the orthopedic community. Emphasizing the significance of TKR in alleviating knee-related disorders, this review underscores the pivotal role of accurate alignment in achieving optimal surgical outcomes. The purpose is to navigate the divide between the well-established mechanical axis approach, focusing on a straight-line alignment, and the anatomical axis approach, aligning with natural knee landmarks. The analysis delves into the advantages, disadvantages, and clinical implications of each approach, offering a nuanced perspective on their efficacy. The conclusion emphasizes a patient-centric approach, recommending the adoption of hybrid strategies and the incorporation of emerging technologies for enhanced precision. The future of TKR aligns with personalized medicine, leveraging advancements in computer-assisted navigation, robotics, and patient-specific implants. Ongoing professional development and interdisciplinary collaboration are crucial for surgeons, and as the field evolves, innovations in artificial intelligence, imaging, and 3D printing are expected to shape the trajectory of TKR alignment approaches.

Case Report: Total Knee Arthroplasty in Ipsilateral Below-Knee Amputee

Introduction

Total knee arthroplasty (TKA) has the highest annual incidence among all joint replacement surgeries. Below-knee amputation (BKA) is another common procedure to treat lower-limb-threatening pathologies. These two procedures are commonly performed individually, but an ipsilateral TKA performed on a BKA patient is rare. While ipsilateral amputation is not a contraindication for TKA, it presents orthopaedic surgeons with a unique case and necessitates thoughtful pre-operative planning regarding proper positioning, alignment determination, surgical technique, and rehabilitation for the best outcome.

Objectives

We present a case of a patient with a BKA who underwent ipsilateral TKA.

Case Report

This patient has a history of osteoarthritis (OA) of the right knee and diabetic neuropathy and underwent a right BKA after sustaining second-degree thermal burns to the bilateral forefeet. The patient was scheduled to undergo elective TKA prior to these injuries but was forced to postpone due to their severity. Following the BKA, the patient regained his ability to ambulate independently with prosthesis but continued to suffer from OA symptoms. The patient was then scheduled for surgery, and a TKA was performed.

Conclusion

The patient underwent a TKA and tolerated the surgery well without complications. Appropriate positioning was achieved using a popliteal post. Alignment and tibial cut were checked using fluoroscopy. All components were cemented into position, and the patella was resurfaced. The patient did well postoperatively and was using his prosthesis and ambulating independently at the final follow-up.

Functional alignment in robotic-assisted total knee arthroplasty: a systematic review

PURPOSE

The present study systematically reviewed current evidence on functional alignment (FA) in robotic total knee arthroplasty (TKA), discussing advantages and limitations, possible pitfalls, and prospects.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase with no additional filters or time constraints. All the clinical studies investigating functional alignment in robotic TKA were accessed. Only studies published in peer-reviewed journals were considered. The risk of bias was evaluated following the guidelines in the Cochrane Handbook for Systematic Reviews of Interventions. Non-randomized controlled trials (non-RCTs) were evaluated using the Risk of Bias in Nonrandomised Studies of Interventions (NRSI) (ROBINS-I) tool.

RESULTS

Data from 1198 patients (seven studies) were retrieved. The mean length of the follow-up was 17.1 ± 6.4 months. The mean age was 67.2 ± 5.4 years, and the mean BMI was 30.9 ± 2.7 kg/m2.

CONCLUSION

FA might improve resection accuracy, implant alignment, and gap balancing in TKA, and additional high-quality clinical trials are necessary to properly establish the superiority of FA to other alignment techniques in TKA. Long-term clinical trials are needed to investigate the impact of FA on implant survivorship.

LEVEL OF EVIDENCE

Level IV, systematic review and meta-analysis.

Water-Tight Arthrotomy Joint Closure of Modified Intervastus Approach in Total Knee Arthroplasty

BACKGROUND

The joint closure technique used for total knee arthroplasty cases can have an impact on outcomes, especially when considering accelerated rehabilitation programs that follow surgery. In this study, we describe the details of the technical steps involved in performing the water-tight arthrotomy joint closure technique that we developed and use.

METHODS

A total of 536 patients (average age: 62 years, average body mass index: 34 kg/m²) with primary osteoarthritis of the knee underwent total knee arthroplasty using the modified intervastus approach between 2019 and 2021. We used the water-tight arthrotomy joint closure technique to close the knee arthrotomy incision. Any infections and complications, as well as the duration of surgery and cost related to this wound closure technique, are also reported.

RESULTS

Few complications were noted with this closure technique. When we first started using it, there was one case of drainage through the proximal capsular repair which required a return to the operating room 5 days postoperatively for an irrigation and debridement. We also had two cases of superficial skin necrosis along a small part of the incision line which were observed on a weekly basis and which healed uneventfully with application of betadine once daily on the necrotic area. The average time for performing wound closure after total knee arthroplasty was 45 min.

CONCLUSION

We conclude that the water-tight closure approach can achieve very durable, water-tight capsule repairs and results in a decrease in postoperative wound drainage.