Cost-effectiveness of patient specific vs conventional instrumentation for total knee arthroplasty: A systematic review and meta-analysis

Size-Up, Size-Down: Accuracy of Component Sizing with Computerized Tomography and Robotic-Assisted Total Knee Arthroplasty

Templating prior to total knee arthroplasty (TKA) can help to improve surgical efficiency and potentially improve alignment and outcomes. The purpose of this article is to evaluate the ability of computed tomography (CT)-based preoperative templating to accurately predict implant sizes. A total of 724 Stryker MAKO robotic-assisted TKA cases were retrospectively evaluated from a prospectively collected database between January 2020 and October 2023. Cases were performed by one of three adult reconstruction fellowship-trained orthopaedic surgeons from a health system that includes an academic level one trauma center, an ambulatory surgery center, and a community hospital. Out of the 724 cases, 391 were preoperatively templated independently by the surgeon and the company representative (MAKO Product Specialist [MPS]). The remaining 333 cases were only templated prior to incision by the MPS. Final implant sizes of the tibial and femoral components were compared to preoperative templates. The MPS was able to preoperatively predict the final tibial and femoral implants within one size in 97.2 and 97.8% of cases, respectively. A surgeon and MPS combined preoperative templating increased accuracy to predict the final tibial and femoral implants within one size in 98.9 and 99.5% of cases, respectively. Height and weight were positively correlated with the final implant size (p < 0.001). Non-surgeons can reliably predict implanted components in CT-based preoperative templating in the majority of cases, which is further enhanced by surgeon review and adjustments. In no cases in our series were the final size components implanted greater than two sizes larger or smaller. Our findings suggest that there is opportunity to avoid waste by processing fewer trial implants and transporting fewer components. This would likely decrease overall case cost and improve efficiency in the operating room. Level of evidence: III (retrospective cohort).

Patient-specific instrumentation improved clinical outcome and implant survival but is not superior compared to conventional total knee arthroplasty: Ten years follow-up of a multicenter double-blind randomized controlled trial

PURPOSE

Patient-specific instrumentation (PSI) is a commonly used technique designed to improve mechanical alignment in total knee arthroplasty (TKA) and was therefore believed to lead to better clinical outcome and implant survival rates compared with conventional instruments (CIs). To date, long-term results comparing these two techniques are not available.

METHODS

This study is a 10-year follow-up of a previous double-blind multicenter randomized controlled trial where PSI was compared with CI. Patients with osteoarthritis of the knee who were candidates for TKA were included. Exclusion criteria were metal near the knee-, ankle- or hip joint, patients with contra-indications for a magnetic resonance imaging (MRI) scan and patients who had previous knee surgery (except arthroscopic meniscectomy). Clinical outcomes were assessed using patient-reported outcome measures (PROMs), and the analysis was performed with a general linear mixed model for repeated measurements. Kaplan-Meier curves were used to compare revision rates. X-rays were obtained and examined by two individual reviewers for any signs of loosening of the components.

RESULTS

At a mean follow-up of 10.1 (SD 0.1) years, 129 patients (loss to follow-up 23%) were analysed in this trial. No statistically significant difference between the two groups were found for any of the PROMs and revision rates were comparable, six in the PSI group and three in the CI group (p = 0.29). Two X-rays in the PSI group showed a radiolucent line of the femoral component.

CONCLUSION

At 10-year follow-up, PSI does not lead to better clinical outcome or survival of the prosthesis compared with CI.

LEVEL OF EVIDENCE

Level 1.

Accuracy of a New Augmented Reality Assisted Technique for Total Knee Arthroplasty: An In Vivo Study

Background

Total knee arthroplasty (TKA) remains the standard of care for treating end-stage osteoarthritis of the knee. Approximately 15%-20% of the patients are dissatisfied following surgery. To improve accuracy and outcomes of TKA, various assistive technologies have been introduced. For this study, an augmented reality (AR) system was explored and tested.

Methods

The Knee + system (Pixee Medical, Besancon, France) was used to guide TKA. It uses a combination of quick response-code labeled instruments and AR glasses to guide tibial and femoral cuts. The primary research goal was to evaluate its accuracy by direct comparing the planned angular values for lateral distal femoral angle, medial proximal tibial angle, hip-knee-ankle axis, and tibial slope to the intraoperative obtained values and the measured angles on postoperative full leg radiographs. The secondary research goal was to assess its feasibility.

Results

This retrospective study evaluated 124 patients, with a follow-up of at least 1 year. The average absolute difference between planned and measured postop values were 1.39° for lateral distal femoral angle, 1.03° for medial proximal tibial angle, 2.16° for tibial slope, and 1.51° for hip-knee-ankle axis. Within the follow-up period, 8 complications were observed. The average surgical time was 83 minutes.

Conclusions

This study has demonstrated a high accuracy, comparable to robotic-assisted total knee arthroplasty, of the Knee + AR system. It has shown to be a safe, cheap and time-efficient assistive technology for patients undergoing medial pivot TKA.

Flexion contracture can cause component mismatch in the Prophecy® preoperative patient-specific instrumentation for Evolution® medial-pivot knee system

INTRODUCTION

Patient-specific instrumentation (PSI) systems are used to conduct total knee arthroplasty. PSI reduces operative time, is less invasive and easier to use, and minimizes the risk of errors by providing precise measurements and reducing operating room turnover time. However, a study on the accuracy of Prophecy Evolution PSI (Microport Inc., Arlington, TN, USA) reported that 94% were below the error margin of 1.5 mm and 90% had error margins of 1 mm. This study aimed to evaluate the accuracy of the Prophecy Evolution PSI system in terms of the thickness of "total" bony resection required to achieve adequate extension/flexion gaps and the component match ratio between preoperative planning and actual component size inserted.

METHODS

Comparisons were made between the sizes of femoral and tibial components planned with PSI and those inserted. The primary outcome was the average preoperative range of motion with and without matched femoral/tibial components. The study further analyzed the proportions of cases in which both the femoral and tibial components matched, neither matched, and only one of the femoral or tibial components matched.

RESULTS

The ratio of the same sizes between the PSI planning and those inserted was 50.8% (33 patients) for both the femoral and tibial components. For the femoral component alone, the ratio was 84.6% (55 patients), and for the tibial component, it was 58.4% (38 patients). A receiver-operating characteristic curve analysis indicated that flexion contracture greater than 20° was a significant prognostic factor for the PSI component match group versus the mismatch group.

DISCUSSION

Flexion contracture may cause PSI mismatch. Notably, flexion contracture greater than 20° was a significant risk factor for the PSI component match group versus the mismatch group. During preoperative planning for a patient with flexion contracture, surgeons should prepare for the possibility of inserting an undersized tibial component.

Shaping the Future of Cardiovascular Disease by 3D Printing Applications in Stent Technology and its Clinical Outcomes

Cardiovascular disease (CVD) is a leading cause of death worldwide. In recent years, 3D printing technology has ushered in a new era of innovation in cardiovascular medicine. 3D printing in CVD management encompasses various aspects, from patient-specific models and preoperative planning to customized medical devices and novel therapeutic approaches. In-stent technology, 3D printing has revolutionized the design and fabrication of intravascular stents, offering tailored solutions for complex anatomies and individualized patient needs. The advantages of 3D-printed stents, such as improved biocompatibility, enhanced mechanical properties, and reduced risk of in-stent restenosis. Moreover, the clinical trials and case studies that shed light on the potential of 3D printing technology to improve patient outcomes and revolutionize the field has been comprehensively discussed. Furthermore, regulatory considerations, and challenges in implementing 3D-printed stents in clinical practice are also addressed, underscoring the need for standardization and quality assurance to ensure patient safety and device reliability. This review highlights a comprehensive resource for clinicians, researchers, and policymakers seeking to harness the full potential of 3D printing technology in the fight against CVD.