A simple method for determining ligament stiffness during total knee arthroplasty in vivo

Völlner, Florian; Weber, Tim; Weber, Markus; Renkawitz, Tobias; Dendorfer, Sebastian; Grifka, Joachim; Craiovan, Benjamin

doi:10.1038/s41598-019-41732-x

Cited by 8 publications

(14 citation statements)

References 22 publications

(26 reference statements)

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“…Stiffness was determined during the standard surgical routine for total knee arthroplasty established at our clinic [21][22][23]. After mid-line skin incision, the capsule was opened using the medial parapatellar approach.…”

Section: Surgical Technique and In Vitro Measurementsmentioning

confidence: 99%

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The effects of soft tissue lateral release on the stability of the ligament complex of the knee

Völlner¹,

Herl²,

Greimel³

et al. 2020

Arch Orthop Trauma Surg

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Purpose Valgus deformity presents a particular challenge in total knee arthroplasty. This condition regularly leads to contractures of the lateral capsular ligament complex and to overstretching of the medial ligamentous complex. Reconstruction of the knee joint kinematics and anatomy often requires lateral release. However, data on how such release weakens the stability of the knee are missing in the literature. This study investigated the effects of sequential lateral release on the collateral stability of the ligament complex of the knee in vitro. Methods Ten knee prostheses were implanted in 10 healthy cadaveric knee joints using a navigation device. Soft tissue lateral release consisted of five release steps, and stiffness and stability were determined at 0, 30, 60 and 90° flexion after each step. Results Soft tissue lateral release increasingly weakened the ligament complex of the lateral compartment. Because of the large muscular parts, the release of the iliotibial band and the M. popliteus had little effect on the stability of the lateral and medial compartment, but release of the lateral ligament significantly decreased the stability in the lateral compartment over the entire range of motion. Stability in the medial compartment was hardly affected. Conversely, further release of the posterolateral capsule and the posterior cruciate ligament led to the loss of stability in the lateral compartment only in deep flexion, whereas stability decreased significantly in the medial compartment. Conclusion Our study shows for the first time the association between sequential lateral release and stability of the ligamentous complex of the knee. To maintain the stability, knee surgeons should avoid releasing the entire lateral collateral ligament, which would significantly decrease stability in the lateral compartment.

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Section: Surgical Technique and In Vitro Measurementsmentioning

confidence: 99%

“…The force-elongation curve was reconstructed with the knee balancer (P.F.C Sigma and LCS Complete EGF Instrumentation of Depuy Synthes, Warsaw, USA), which displays the applied force and elongation at all times. Therefore, the device had been validated prior to the study [23].…”

Section: Reconstruction Of the Force-elongation Curvementioning

confidence: 99%

The effects of soft tissue lateral release on the stability of the ligament complex of the knee

Völlner¹,

Herl²,

Greimel³

et al. 2020

Arch Orthop Trauma Surg

Self Cite

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“…E.g. for a ligament stiffness of 80 N/mm for both compartments [4] 1 mm local condylar offset may result in 80 N additional knee forces, additional ligament strain or instability due to ligament relaxation. Therefore, efforts need to be taken to better replicate the J-Curve of the native knee in order to better restore patient-specific kinematics as well as ligament strain and tension.…”

Section: Introductionmentioning

confidence: 99%

Variation of the femoral J-Curve in the native knee

Grothues¹,

Asseln²,

Radermacher³

EPiC Series in Health Sciences

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The J-Curve in the native knee as well as the femoral component’s J-Curve after total knee arthroplasty are known to have a high influence on kinematics. Furthermore, the J-Curve’s shape affects ligament strain and tension and consequently already slight changes may strongly alter knee forces and stability. To optimize current implants’ J-Curve design with regard to the population’s morphology, information about the main sources of contour variation is necessary.In this study, a principal component analysis (PCA) was performed on the medial and lateral femoral J-Curves of 90 cadavers without history of osteoarthritis. The J-Curves’ mean shapes were further investigated by geometric parameter analysis and effect sizes were calculated for the first three principal components (PCs). In addition, a combined PCA for both sides was performed and evaluated qualitatively. The results were compared with the variation in standard implants’ J-Curve shape.The isolated PCA of medial and lateral J-Curves resulted in PCs involving changes in contour orientation, arc length, scaling and circularity. The combined PCA of both sides resulted in PCs comprising combinations of the individual variations together with changes in relative position. In contrast, the qualitative evaluation of J-Curves from 2 different standard implant systems revealed no visible changes in shape but only changes in size.Limitations of this study were the restriction to a 2-dimensional contour derivation and the sole consideration of the femoral contours. Nevertheless, the sagittal variability in the medial, lateral and combined femoral J-Curves should be considered in implant design.

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“…Determining a desirable amount of ligament tension is crucial for total knee arthroplasty (TKA) as instability is a leading cause for revision surgery [1,2,3]. Little data exists on optimizing joint space tension during TKA.…”

Section: Introductionmentioning

confidence: 99%

“…The point at which this behavior change occurs is defined as the stiffness transition point (STP). Ligament properties are subject specific, varying widely based on factors such as sex, BMI and age [3,6]. This study aims to characterize ligament stiffness profiles intraoperatively to identify the STP.…”

Section: Introductionmentioning

confidence: 99%

Optimizing TKA Positioning via Intraoperative Ligament Characterization

Orsi¹,

Wakelin²,

Shalhoub³

et al.

EPiC Series in Health Sciences

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The goal of total knee arthroplasty (TKA) is to position the prosthesis with a bal- anced soft tissue envelope throughout the flexion cycle. Determining a desirable amount of ligament tension is crucial as instability is a leading cause for revision surgery. This is challenging due to the subject specific, and non-linear, nature of ligament mechanical properties. This study aims to characterize ligament stiffness profiles intraoperatively and identify the stiffness transition point (STP) using a ligament balancing robot. The study will also identify how the surgeon selected joint force relates to the stiffness transition point.45 patients were reviewed. After the proximal tibial resection, intraoperative assessment of the medial and lateral ligaments was performed via a load cycle ramped up from 50N to 120N, then down from 120N to 50N. This was performed at extension (10◦) and in flexion (90◦). Force and displacement data were processed to determine the stiffness profiles for the medial and lateral soft tissue envelope. A bilinear fit model was used to determine the slopes and STP.The average STP was between 83N and 90N, varying widely with standard deviations approaching 14N. The median joint tension selected by the surgeon was 80N. On average the selected joint force was 3N to 8.9N below the STP.The medial compartment behaved similarly in extension and flexion. The lateral com- partment had higher stiffness in extension than in flexion. Across all loading conditions, the down-cycle data was more consistent than the up-cycle data.The STP is a proposed target for ligament tension as this theoretically avoids the high stiffness regime. The results show the joint tension selected by the surgeons, based on their experience and intraoperative feel, is similar to the STP. Due to the high patient variability observed in the STP, using a patient specific method to determine the joint tension is recommended. Future work will investigate how joint tension relative to the STP affects patient outcomes. This will provide insight into optimizing joint tension during TKA.

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A simple method for determining ligament stiffness during total knee arthroplasty in vivo

Cited by 8 publications

References 22 publications

The effects of soft tissue lateral release on the stability of the ligament complex of the knee

The effects of soft tissue lateral release on the stability of the ligament complex of the knee

Variation of the femoral J-Curve in the native knee

Optimizing TKA Positioning via Intraoperative Ligament Characterization

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