Robotically Simulated Pivot Shift That Represents the Clinical Exam

Colbrunn, Robb; Dumpe, Jarrod; Nagle, Tara F.; Kolmodin, Joel; Barsoum, Wael K.; Saluan, Paul

doi:10.1002/jor.24439

Cited by 14 publications

(31 citation statements)

References 31 publications

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“…However, qualitative analysis of trend plots, and the fact that the replicated activities are on the same time scale as the original motion capture, indicate an acceptable replication of load rate. This in contrast to other investigations that temporally scale in vivo kinematics by a factor of 4 to 50 [14,17,28,56], even for relatively slow tasks such as walking.…”

Section: Plos Onementioning

confidence: 69%

“…derived from inverse dynamics, force control can be employed. However, accurate force replication necessitates temporal scaling, leading to poor replication of load rate [17]. While joint simulators extend biomechanical testing beyond the confines of a UTM, the sub-physiologic speeds and load rates fail to reproduce the inertial environment necessary to investigate bone-prosthetic interface biomechanics.…”

Section: Introductionmentioning

confidence: 99%

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Replicating dynamic humerus motion using an industrial robot

et al. 2020

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Transhumeral percutaneous osseointegrated prostheses provide upper-extremity amputees with increased range of motion, more natural movement patterns, and enhanced proprioception. However, direct skeletal attachment of the endoprosthesis elevates the risk of bone fracture, which could necessitate revision surgery or result in loss of the residual limb. Bone fracture loads are direction dependent, strain rate dependent, and load rate dependent. Furthermore, in vivo, bone experiences multiaxial loading. Yet, mechanical characterization of the bone-implant interface is still performed with simple uni- or bi-axial loading scenarios that do not replicate the dynamic multiaxial loading environment inherent in human motion. The objective of this investigation was to reproduce the dynamic multiaxial loading conditions that the humerus experiences in vivo by robotically replicating humeral kinematics of advanced activities of daily living typical of an active amputee population. Specifically, 115 jumping jack, 105 jogging, 15 jug lift, and 15 internal rotation trials—previously recorded via skin-marker motion capture—were replicated on an industrial robot and the resulting humeral trajectories were verified using an optical tracking system. To achieve this goal, a computational pipeline that accepts a motion capture trajectory as input and outputs a motion program for an industrial robot was implemented, validated, and made accessible via public code repositories. The industrial manipulator utilized in this study was able to robotically replicate over 95% of the aforementioned trials to within the characteristic error present in skin-marker derived motion capture datasets. This investigation demonstrates the ability to robotically replicate human motion that recapitulates the inertial forces and moments of high-speed, multiaxial activities for biomechanical and orthopaedic investigations. It also establishes a library of robotically replicated motions that can be utilized in future studies to characterize the interaction of prosthetic devices with the skeletal system, and introduces a computational pipeline for expanding this motion library.

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Section: Plos Onementioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Replicating dynamic humerus motion using an industrial robot

et al. 2020

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“…These flexion angles are within a range where clinical and functional pivoting events occur. 9,17,32,41,46,55 The first set of applied pivoting loads consisted of serially applied valgus (8 N·m) and internal rotation (4 N·m) torques (pivot shift 1 [PS1]); this test acts to subluxate the lateral compartment. 34,53 The second set of applied pivoting loads (pivot shift 2 [PS2]) was based on those previously measured while performing a pivot-shift examination.…”

Section: Methodsmentioning

confidence: 99%

“…34,53 The second set of applied pivoting loads (pivot shift 2 [PS2]) was based on those previously measured while performing a pivot-shift examination. 9 These serially applied loads were compression (100 N), an important component of the pivot mechanism 5 ; valgus torque (8 N·m); internal rotation torque (2 N·m); and anterior force (30 N). 9,53,55 For each loading condition, the tibia was free to move in all directions save for flexion-extension.…”

Section: Methodsmentioning

confidence: 99%

Lateral Extra-articular Tenodesis Reduces Anterior Cruciate Ligament Graft Force and Anterior Tibial Translation in Response to Applied Pivoting and Anterior Drawer Loads

et al. 2020

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Background: The biomechanical effect of lateral extra-articular tenodesis (LET) performed in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) on load sharing between the ACL graft and the LET and on knee kinematics is not clear. Purpose/Hypothesis: The purpose was to quantify the effect of LET on (1) forces carried by both the ACL graft and the LET and (2) tibiofemoral kinematics in response to simulated pivot shift and anterior laxity tests. We hypothesized that LET would decrease forces carried by the ACL graft and anterior tibial translation (ATT) in response to simulated pivoting maneuvers and during simulated tests of anterior laxity. Study Design: Controlled laboratory study. Methods: Seven cadaveric knees (mean age, 39 ± 12 years [range, 28-54 years]; 4 male) were mounted to a robotic manipulator. The robot simulated clinical pivoting maneuvers and tests of anterior laxity: namely, the Lachman and anterior drawer tests. Each knee was assessed in the following states: ACL intact, ACL sectioned, ACL reconstructed (using a bone–patellar tendon–bone autograft), and after performing LET (the modified Lemaire technique after sectioning of the anterolateral ligament and Kaplan fibers). Resultant forces carried by the ACL graft and LET at the peak applied loads were determined via superposition. ATT was determined in response to the applied loads. Results: With the applied pivoting loads, performing LET decreased ACL graft force up to 80% (44 ± 12 N; P < .001) and decreased ATT of the lateral compartment compared with that of the intact knee up to 7.6 ± 2.9 mm ( P < .001). The LET carried up to 91% of the force generated in the ACL graft during isolated ACLR (without LET). For simulated tests of anterior laxity, performing LET decreased ACL graft force by 70% (40 ± 20 N; P = .001) for the anterior drawer test with no significant difference detected for the Lachman test. No differences in ATT were deteced between ACLR with LET and the intact knee on both the Lachman and the anterior drawer tests ( P = .409). LET reduced ATT compared with isolated ACLR on the simulated anterior drawer test by 2.4 ± 1.8 mm ( P = .032) but not on the simulated Lachman test. Conclusion: In a cadaveric model, LET in combination with ACLR transferred loads from the ACL graft to the LET and reduced ATT with applied pivoting loads and during the simulated anterior drawer test. The effect of LET on ACL graft force and ATT was less pronounced on the simulated Lachman test. Clinical Relevance: LET in addition to ACLR may be a suitable option to offload the ACL graft and to reduce ATT in the lateral compartment to magnitudes less than that of the intact knee with clinical pivoting maneuvers. In contrast, LET did not offload the ACL graft or add to the anterior restraint provided by the ACL graft during the Lachman test.

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“…29 The second PS load combination (PS2) incorporated compression (100 N), valgus torque (8 NÁm), internal rotation torque (2 NÁm), and anterior force (30 N). 12 For each simulated PS, loads were applied in series; as each applied load reached its maximum, it was held constant and the next load was increased to its maximum. Tibiofemoral kinematics in response to the applied pivoting loads were recorded.…”

Section: Loading Conditionsmentioning

confidence: 99%

Lateral Extra-articular Tenodesis Alters Lateral Compartment Contact Mechanics under Simulated Pivoting Maneuvers: An In Vitro Study

et al. 2021

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Background: There is concern that utilization of lateral extra-articular tenodesis (LET) in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) may disturb lateral compartment contact mechanics and contribute to joint degeneration. Hypothesis: ACLR augmented with LET will alter lateral compartment contact mechanics in response to simulated pivoting maneuvers. Study Design: Controlled laboratory study. Methods: Loads simulating a pivot shift were applied to 7 cadaveric knees (4 male; mean age, 39 ± 12 years; range, 28-54 years) using a robotic manipulator. Each knee was tested with the ACL intact, sectioned, reconstructed (via patellar tendon autograft), and, finally, after augmenting ACLR with LET (using a modified Lemaire technique) in the presence of a sectioned anterolateral ligament and Kaplan fibers. Lateral compartment contact mechanics were measured using a contact stress transducer. Outcome measures were anteroposterior location of the center of contact stress (CCS), contact force from anterior to posterior, and peak and mean contact stress. Results: On average, augmenting ACLR with LET shifted the lateral compartment CCS anteriorly compared with the intact knee and compared with ACLR in isolation by a maximum of 5.4 ± 2.3 mm ( P < .001) and 6.0 ± 2.6 mm ( P < .001), respectively. ACLR augmented with LET also increased contact force anteriorly on the lateral tibial plateau compared with the intact knee and compared with isolated ACLR by a maximum of 12 ± 6 N ( P = .001) and 17 ± 10 N ( P = .002), respectively. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress by 0.7 ± 0.5 MPa ( P = .005) and by 0.17 ± 0.12 ( P = .006), respectively, at 15° of flexion. Conclusion: Under simulated pivoting loads, adding LET to ACLR anteriorized the CCS on the lateral tibial plateau, thereby increasing contact force anteriorly. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress at 15° of flexion. Clinical Relevance: The clinical and biological effect of increased anterior loading of the lateral compartment after LET merits further investigation. The ability of LET to anteriorize contact stress on the lateral compartment may be useful in knees with passive anterior subluxation of the lateral tibia.

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Robotically Simulated Pivot Shift That Represents the Clinical Exam

Cited by 14 publications

References 31 publications

Replicating dynamic humerus motion using an industrial robot

Replicating dynamic humerus motion using an industrial robot

Lateral Extra-articular Tenodesis Reduces Anterior Cruciate Ligament Graft Force and Anterior Tibial Translation in Response to Applied Pivoting and Anterior Drawer Loads

Lateral Extra-articular Tenodesis Alters Lateral Compartment Contact Mechanics under Simulated Pivoting Maneuvers: An In Vitro Study

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