Location of the ankle center for total knee arthroplasty

Vermue

Robotics Computer Surgery

et al. 2022

Background:The intraoperative registration of the bones play a crucial role in image-based computer-assisted knee arthroplasty to achieve accurate implant placement and to create reliable stereotactic bone boundaries for robot-assisted surgical systems. Method:This study assessed the intraoperative registration accuracy on six intact fresh frozen cadavers.Results: Rotational errors around the mechanical axis were the largest, with a standard deviation of 1.2°and outliers up to 3.7°. The mean translational errors were lower than 1 mm, with outliers up to 1.5 mm. These errors were amplified to 2 mm for the registration-based reconstruction of the posterior bone surface at the resection levels. Conclusion:Given the cumulative behaviour of surgical errors, registration errors can affect the final implant positioning. Furthermore, inaccuracies in the reconstructed bone boundary directly affect the virtual stereotactic boundaries used in robotic-assisted surgery and can result in an incomplete resection or inadvertent soft tissue damage. K E Y W O R D Sanatomy, technology | INTRODUCTIONTotal knee arthroplasty (TKA) is a common and cost-effective surgical treatment for osteoarthritis of the knee joint. 1 However, 10%-20% of patients remain dissatisfied after TKA. 2 Malpositioning of the implant is associated with implant failure, and as a result, patient dissatisfaction. 3,4 To improve the accuracy of the implant position according to a preoperative plan, navigation and robotics have been introduced. 5 These technologies have proven to be successful in reducing the frequency of outliers of more than 3°, but errors up to these values still occur. [6][7][8][9][10] Navigation and robotic systems are in most cases using an optical tracking system (OTS) and a tracked pointer to determine the position and orientation of the femur and tibia with respect to the attached dynamic reference bases (DRB). 9,11,12 This intraoperative bone registration process is subject to a margin of error which affects the surgical accuracy. [11][12][13][14][15] The total operative accuracy is determined by a succession of inaccuracies in the following surgical steps: bone registration and matching of the surgical plan, tracking of the bones and the surgical objects in space, bone preparation and implant placement. During bone registration, the software model is matched with the patient's specific anatomy. As

Section: Discussionmentioning

confidence: 70%

Accuracy of intraoperative bone registration and stereotactic boundary reconstruction during total knee arthroplasty surgery

Vermue

Robotics Computer Surgery

et al. 2022

“…Shigeki analyzed CT data, found that the mean offset distance with reference to the tibial AP axis was 1.8 AE 0.9 mm medial to the intermalleolar midpoint on the coronal plane. The intermalleolar midpoint in the coronal plane is a reliable landmark for the ankle center during TKA 23 .…”

Section: Medial and Lateral Ankle Midpointsmentioning

confidence: 99%

Efficacy Analysis of Selection of Distal Reference Point for Tibial Coronal Plane Osteotomy during Total Knee Arthroplasty: A Literature Review

Men

Liang

Wang

et al. 2021

Orthopaedic Surgery

Total knee arthroplasty is an effective treatment for end-stage knee osteoarthritis. The tibial platform osteotomy must take full account of the coronal plane, the sagittal plane, and the rotational alignment of the tibial prosthesis. During surgery, individual differences in the coronal alignment of the tibia need to be taken into account as poor alignment after surgery can lead to rapid wear of the tibial platform, reducing the longevity of the prosthesis and adversely affecting quality of life. Intraoperative tibial osteotomies are often performed using extramedullary alignment. When an extramedullary alignment approach is used, the proximal tibial osteotomy guide is usually placed in the medial third of the tibial tuberosity. There is no consensus on the most reliable anatomical landmarks or axes for achieving distal tibial coronary alignment. Anatomical points or reference axes that are highly reproducible and precise need to be identified. From available data it appears that most surgeons use the extensor hallucis longus tendon, the second metatarsal, and the anterior tibial cortex to determine the distal localization point. However, its accuracy has not been confirmed in clinical and radiographic data, and the alignment concept and preoperative planning for total knee arthroplasty has paid more attention to rotational alignment, but there are few studies on the coronal alignment of the tibia. This article reviews the recent use of the distal tibial coronal osteotomy reference point in total knee arthroplasty. However, due to there being only a small number of studies available, the evidence collected is insufficient to prove that a certain reference axis has obvious advantages and a combination of different reference points is needed to achieve the ideal lower extremity force line angle.

“…14 Though several attempts have been made to understand the associations between tibial alignment methods, landmarks including ankle centre of rotation, and resultant coronal plane resection angles, these studies are limited by small sample sizes and methodology subject to human error. 6,7,13 The use of artificial intelligence and deep learning to identify and compare clinically relevant anatomical landmarks for tibial bone resection is poised to overcome the limitations in subjective variability and measurement time burden inherent to human measurement. The purpose of the current study was to determine the accuracy and effect of using different radiological distal tibial anatomical landmarks for knee alignment in relation to a traditionally defined radiological ankle centre.…”

Section: Introductionmentioning

confidence: 99%

“… 3 This misalignment may be accentuated and unavoidable in cases where the tibial mechanical and anatomical axes differ, such as in patients with proximal tibia bowing deformities. 6 As such, identifying the ankle centre is imperative to obtain accurate tibial alignment measurements and potentially avoid adverse events associated with tibial component malposition in the coronal plane.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of tibial alignment parameters based on clinically relevant anatomical landmarks

et al. 2022

Aims Accurate identification of the ankle joint centre is critical for estimating tibial coronal alignment in total knee arthroplasty (TKA). The purpose of the current study was to leverage artificial intelligence (AI) to determine the accuracy and effect of using different radiological anatomical landmarks to quantify mechanical alignment in relation to a traditionally defined radiological ankle centre. Methods Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A sub-cohort of 250 radiographs were annotated for landmarks relevant to knee alignment and used to train a deep learning (U-Net) workflow for angle calculation on the entire database. The radiological ankle centre was defined as the midpoint of the superior talus edge/tibial plafond. Knee alignment (hip-knee-ankle angle) was compared against 1) midpoint of the most prominent malleoli points, 2) midpoint of the soft-tissue overlying malleoli, and 3) midpoint of the soft-tissue sulcus above the malleoli. Results A total of 932 bilateral full-limb radiographs (1,864 knees) were measured at a rate of 20.63 seconds/image. The knee alignment using the radiological ankle centre was accurate against ground truth radiologist measurements (inter-class correlation coefficient (ICC) = 0.99 (0.98 to 0.99)). Compared to the radiological ankle centre, the mean midpoint of the malleoli was 2.3 mm (SD 1.3) lateral and 5.2 mm (SD 2.4) distal, shifting alignment by 0.34o (SD 2.4o) valgus, whereas the midpoint of the soft-tissue sulcus was 4.69 mm (SD 3.55) lateral and 32.4 mm (SD 12.4) proximal, shifting alignment by 0.65o (SD 0.55o) valgus. On the intermalleolar line, measuring a point at 46% (SD 2%) of the intermalleolar width from the medial malleoli (2.38 mm medial adjustment from midpoint) resulted in knee alignment identical to using the radiological ankle centre. Conclusion The current study leveraged AI to create a consistent and objective model that can estimate patient-specific adjustments necessary for optimal landmark usage in extramedullary and computer-guided navigation for tibial coronal alignment to match radiological planning. Cite this article: Bone Jt Open 2022;3(10):767–776.