Measurement of shoulder joint loads during wheelchair propulsion measured in vivo

Background: Lesions of the long head of the biceps tendon are often associated with massive rotator cuff tears (MRCTs), and biceps tenotomy is frequently performed for pain relief and functional reservation. However, the efficacy and safety of biceps tenotomy regarding the effects on the surrounding tissues in chronic MRCT are unclear. Hypothesis: Biceps tenotomy would result in improved mechanical and histological properties of the intact subscapularis tendon and improved in vivo shoulder function while not compromising glenoid cartilage properties. Study Design: Controlled laboratory study. Methods: Right supraspinatus and infraspinatus tendons were detached in 25 male Sprague-Dawley rats, followed by 4 weeks of cage activity to create a chronic MRCT condition. Animals were randomly divided into 2 groups and received either biceps tenotomy (n = 11) or sham surgery (n = 14) and were sacrificed 4 weeks thereafter. Forelimb gait and ground-reaction forces were recorded 1 day before the tendon detachment (baseline), 1 day before the surgical intervention (biceps tenotomy or sham), and 3, 7, 10, 14, 21, and 28 days after the intervention to assess in vivo shoulder joint function. The subscapularis tendon and glenoid cartilage were randomly allocated for mechanical testing or histologic assessment after the sacrifice. Results: Compared with sham surgery, biceps tenotomy partially restored the in vivo shoulder joint function, with several gait and ground-reaction force parameters returning closer to preinjury baseline values at 4 weeks. With biceps tenotomy, mechanical properties of the subscapularis tendons were improved, while mechanical properties and histological Mankin scores of the glenoid cartilage were not diminished when compared with the sham group. Conclusion: Biceps tenotomy in the presence of chronic MRCT partially preserves overall shoulder function and potentially restores subscapularis tendon health without causing detrimental effects to joint cartilage. This laboratory study adds to the growing literature regarding the protective effects of biceps tenotomy on the shoulder joint in a chronic MRCT model. Clinical Relevance: This study provides important basic science evidence supporting the use of biceps tenotomy in patients with massive rotator cuff tears.

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In vivo estimation of the shoulder joint center of rotation using magneto-inertial sensors: MRI-based accuracy and repeatability assessment

BioMedical Engineering OnLine ◽

10.1186/s12938-017-0324-0 ◽

2017 ◽

Vol 16 (1) ◽

Cited By ~ 17

Author(s):

M. Crabolu ◽

D. Pani ◽

L. Raffo ◽

M. Conti ◽

P. Crivelli ◽

...

Keyword(s):

Shoulder Joint ◽

Inertial Sensors ◽

Center Of Rotation ◽

Joint Center ◽

Accuracy And Repeatability

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IN VIVO SHOULDER JOINT FORCES AT ISOLATED MOTIONS

Journal of Biomechanics ◽

10.1016/s0021-9290(08)70144-1 ◽

2008 ◽

Vol 41 ◽

pp. S144 ◽

Cited By ~ 6

Author(s):

Peter Westerhoff ◽

Antonius Rohlmann ◽

A. Bender ◽

Friedmar Graichen ◽

Georg Bergmann

Keyword(s):

Shoulder Joint ◽

Joint Forces

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Influence of Comprehensive Joint Loads on Tibial Implant Micromotion in Total Ankle Arthroplasty

Foot & Ankle Orthopaedics ◽

10.1177/2473011420s00084 ◽

2020 ◽

Vol 5 (4) ◽

pp. 2473011420S0008

Author(s):

Brett D. Steineman ◽

Constantine A. Demetracopoulos ◽

Jonathan T. Deland ◽

Brett D. Steineman ◽

Fernando Quevedo Gonzalez ◽

...

Keyword(s):

Finite Element ◽

Ankle Joint ◽

Compressive Load ◽

Compressive Force ◽

Axial Loading ◽

Loading Conditions ◽

Bone Implant ◽

Level Walking ◽

Joint Loads

Category: Ankle Introduction/Purpose: Biologic fixation of total joint replacements by bone ingrowth requires minimal bone-implant micromotion [1]. Computational finite element (FE) models used to evaluate the interaction between implant and bone typically only consider simplified loading conditions based on the peak compressive force which occurs near toe-off [2,3]. However, a previous study focused on cementless knee replacements demonstrated that peak micromotion during activity cycles occurred with sub-maximal forces and moments [4]. Our objective was to calculate multi-axial loading at the ankle joint throughout level walking and evaluate tibial fixation of ankle replacements under these loading conditions. We hypothesized that peak micromotion would occur with sub-maximal loads and moments instead of at the instant of peak compressive load. Methods: Our validated six-degree-of-freedom robotic simulator utilizes in vivo data from human subjects to replicate the individual bone kinematics in cadaveric specimen throughout activity [5]. We rigidly fixed retro-reflective markers using bone pins to the tibia, talus, and calcaneus bones of three cadaveric specimens to record individual bone kinematics using motion capture cameras. We recorded the ground reaction and muscle-tendon forces during the simulated stance phase of level walking. Musculoskeletal models were then developed in OpenSim using the specimen-specific morphology and implant position from CT- scans and from the simulator outputs to determine the loading profile at the ankle joint during stance. The calculated loads were then applied to specimen-specific finite element models to evaluate the bone-implant interaction. Peak micromotion at each time point of loading was measured and compared to the loading profile to determine if it corresponded with the peak compressive load. Results: For all specimens, the peak compressive load at the ankle joint was accompanied by multi-axial moments and relatively small shear forces (Figure 1). The peak compressive load for each specimens was between 750 N and 850 N and occurred during 75-80% of gait. The largest moment experienced by all specimens was an internal moment late in stance. The peak micromotion for each specimen did not correspond to the instance of peak compressive load, as indicated in Figure 1. Instead, peak micromotion occurred at 54%, 88%, and 96% of gait. For each specimen, these instances corresponded to the combination of a sub-maximal compressive load with high eversion and internal moments. Conclusion: We have developed a workflow to calculate ankle joint loads corresponding to cadaveric simulations that reproduce a daily activity based on in vivo data. The specimen-specific, multi-axial loading profile at the ankle for our initial results suggests that peak micromotion at the bone-implant interface of the tibial implant does not coincide with the peak compressive force. The instant of peak compressive load may not capture the worst-case scenario for the interaction between the implant and the bone. Instead, the multi-axial forces and moments at the ankle joint throughout activity should be considered when evaluating implant fixation.

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