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Zitnay JL, Tashjian RZ, Walch G, Chalmers PN, Joyce CD, Henninger HB. Inlay vs. onlay humeral components in reverse total shoulder arthroplasty: a biorobotic shoulder simulator study. J Shoulder Elbow Surg 2024; 33:1377-1386. [PMID: 38036254 PMCID: PMC11098709 DOI: 10.1016/j.jse.2023.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/09/2023] [Accepted: 10/22/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND Both inlay and onlay humeral implants are available for reverse total shoulder arthroplasty (rTSA), but biomechanical data comparing these components remain limited. This study investigated the effects of inlay and onlay rTSA humeral components on shoulder biomechanics using a biorobotic shoulder simulator. METHODS Twenty fresh-frozen cadaveric shoulders were tested before and after rTSA with either an inlay or onlay humeral implant. Comparisons were performed between the most commonly implanted configurations for each implant (baseline) and with a modification to provide equivalent neck-shaft angles (NSAs) for the inlay and onlay configurations. Specimens underwent passive range-of-motion (ROM) assessment with the scapula held static, and scapular-plane abduction was performed, driven by previously collected human-subject scapulothoracic and glenohumeral kinematics. Passive ROM glenohumeral joint angles were compared using t tests, whereas muscle force and excursion data during scapular-plane elevation were evaluated with statistical parametric mapping and t tests. RESULTS Maximum passive elevation was reduced for the inlay vs. onlay humeral components, although both implants caused reduced passive elevation vs. the native joint. Inlay rTSA also demonstrated reduced passive internal rotation at rest and increased external rotation at 90° of humerothoracic elevation vs. the native joint. All preoperative planning estimates of ROM differed from experiments. Rotator cuff forces were elevated with an onlay vs. inlay humeral implant, but simulated muscle excursions did not differ between systems. Compared with the native joint, rotator cuff forces were increased for both inlay and onlay implants and deltoid forces were reduced for inlay implants. Muscle excursions were dramatically altered by rTSA vs. the native joint. Comparisons of inlay and onlay humeral implants with equivalent NSAs were consistent with the baseline comparisons. CONCLUSIONS Rotator cuff forces required to perform scapular-plane abduction increase following rTSA using both inlay and onlay implants. Rotator cuff forces are lower with inlay implants compared with onlay implants, although inlay implants also result in reduced passive-elevation ROM. Deltoid forces are lower with inlay implants in comparison to the native joint but not with onlay implants. The differences between inlay and onlay components are largely unaffected by NSA, indicating that these differences are inherent to the inlay and onlay designs. In those patients with an intact rotator cuff, decreased rotator cuff forces to perform abduction with an inlay humeral implant compared with an onlay implant may promote improved long-term outcomes owing to reduced deltoid muscle fatigue when using an inlay implant.
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Affiliation(s)
- Jared L Zitnay
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Robert Z Tashjian
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Gilles Walch
- Hôpital Privé Jean Mermoz-Groupe Ramsay, Centre Orthopédique Santy, Lyon, France
| | - Peter N Chalmers
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | | | - Heath B Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA.
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Axford DT, Potra R, Appleyard R, Tomka J, Arenas-Miquelez A, Bokor D, Ferreira L, Raniga S. Development of a Cadaveric Shoulder Motion Simulator with Open-Loop Iterative Learning for Dynamic, Multiplanar Motion: A Preliminary Study. J Clin Med 2023; 12:4596. [PMID: 37510711 PMCID: PMC10380955 DOI: 10.3390/jcm12144596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/26/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Ex vivo shoulder motion simulators are commonly used to study shoulder biomechanics but are often limited to performing simple planar motions at quasi-static speeds using control architectures that do not allow muscles to be deactivated. The purpose of this study was to develop an open-loop tendon excursion controller with iterative learning and independent muscle control to simulate complex multiplanar motion at functional speeds and allow for muscle deactivation. The simulator performed abduction/adduction, faceted circumduction, and abduction/adduction (subscapularis deactivation) using a cadaveric shoulder with an implanted reverse total shoulder prosthesis. Kinematic tracking accuracy and repeatability were assessed using maximum absolute error (MAE), root mean square error (RMSE), and average standard deviation (ASD). During abduction/adduction and faceted circumduction, the RMSE did not exceed 0.3, 0.7, and 0.8 degrees for elevation, plane of elevation, and axial rotation, respectively. During abduction/adduction, the ASD did not exceed 0.2 degrees. Abduction/adduction (subscapularis deactivation) resulted in a loss of internal rotation, which could not be restored at low elevation angles. This study presents a novel control architecture, which can accurately simulate complex glenohumeral motion. This simulator will be used as a testing platform to examine the effect of shoulder pathology, treatment, and rehabilitation on joint biomechanics during functional shoulder movements.
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Affiliation(s)
- David Timothy Axford
- Department of Mechanical and Materials Engineering, Western University, London, ON N6A 3K7, Canada
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Robert Potra
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
- Department of Electrical and Computer Engineering, Western University, London, ON N6A 3K7, Canada
| | - Richard Appleyard
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Janos Tomka
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Antonio Arenas-Miquelez
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Desmond Bokor
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Louis Ferreira
- Department of Mechanical and Materials Engineering, Western University, London, ON N6A 3K7, Canada
| | - Sumit Raniga
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Knighton TW, Chalmers PN, Sulkar HJ, Aliaj K, Tashjian RZ, Henninger HB. Reverse total shoulder glenoid component inclination affects glenohumeral kinetics during abduction: a cadaveric study. J Shoulder Elbow Surg 2022; 31:2647-2656. [PMID: 35931329 PMCID: PMC9669184 DOI: 10.1016/j.jse.2022.06.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/02/2022] [Accepted: 06/27/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Optimal implant placement in reverse total shoulder arthroplasty (rTSA) remains controversial. Specifically, the optimal glenoid inclination is unknown. Therefore, a cadaveric shoulder simulator with 3-dimentional human motion specific to rTSA was used to study joint contact and muscle forces as a function of glenoid component inclination. METHODS Eight human cadaver shoulders were tested before and after rTSA implantation. Scapular plane abduction kinematics from control subjects and those with rTSA drove a cadaveric shoulder simulator with 3-dimentional scapulothoracic and glenohumeral motion. Glenoid inclination varied from -20° to +20°. Outputs included compression, superior-inferior (S/I) shear, and anterior-posterior shear forces from a 6° of freedom load cell in the joint, and deltoid and rotator cuff muscle forces. Data were evaluated with statistical parametric mapping and t-tests. RESULTS Inferior glenoid inclination (-) reduced S/I shear by up to 125% relative to superior inclination, with similar compression to the neutral condition (0°). Superior inclinations (+) increased the S/I shear force by approximately the same magnitude, yet decreased compression by 25% in the most superior inclination (+20°). There were few differences in deltoid or rotator cuff forces due to inclination. Only the middle deltoid decreased by approximately 7% for the most inferior inclination (-20°). Compared with native shoulders, the neutral (0°) rTSA inclination showed reduced forces of 30%-75% in the anterior deltoid and a trend toward decreased forces in the middle deltoid. Force demands on the rotator cuff varied as a function of elevation, with a trend toward increased forces in rTSA at peak glenohumeral elevation. CONCLUSIONS Inferior inclination reduces superior shear forces, without influencing compression. Superior inclination increased S/I shear, while decreasing compression, which may be a source of component loosening and joint instability after rTSA. Inferior inclination of the rTSA glenoid may reduce the likelihood of glenoid loosening by reducing the magnitude of cyclic shear and compressive loading during arm elevation activities, although this may be altered by specific-subject body habitus and motion. These factors are especially important in revision rTSA or glenoid bone grafting where there is already a 3-fold increase in glenoid baseplate loosening vs. primary rTSA.
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Affiliation(s)
- Tyler W Knighton
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Peter N Chalmers
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Hema J Sulkar
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Klevis Aliaj
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Robert Z Tashjian
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Heath B Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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Knighton TW, Chalmers PN, Sulkar HJ, Aliaj K, Tashjian RZ, Henninger HB. Anatomic total shoulder glenoid component inclination affects glenohumeral kinetics during abduction: a cadaveric study. J Shoulder Elbow Surg 2022; 31:2023-2033. [PMID: 35550434 PMCID: PMC9481675 DOI: 10.1016/j.jse.2022.03.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/23/2022] [Accepted: 03/27/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Although typically favorable in outcome, anatomic total shoulder arthroplasty (aTSA) can require long-term revision. The most common cause for revision is glenoid loosening, which may result from eccentric cyclic forces and joint translations. "Rocking" of the glenoid component may be exacerbated by the joint geometry, such as glenoid inclination and version. Restoration of premorbid glenoid inclination may be preferable, although laboratory and computational models indicate that both superior inclination and inferior inclination have benefits. This discrepancy may arise because previous studies were limited by a lack of physiological conditions to test inclination. Therefore, a cadaveric shoulder simulator with 3-dimensional human motion was used to study joint contact and muscle forces with isolated changes in glenoid inclination. METHODS Eight human cadaveric shoulders were tested before and after aTSA. Scapular-plane abduction kinematics from human subjects were used to drive a cadaveric shoulder simulator with 3-dimensional scapulothoracic and glenohumeral motion. Glenoid inclination was varied from -10° to +20°, whereas compressive, superior-inferior shear, and anterior-posterior shear forces were collected with a 6-df load cell during motion. Outputs also included muscle forces of the deltoid and rotator cuff. Data were evaluated with statistical parametric mapping repeated-measures analysis of variance and t tests. RESULTS Inferior glenoid inclination (-10°) reduced both compressive and superior-inferior shear forces vs. neutral 0° inclination by up to 40%, and even more when compared with superior inclination (P < .001). Superior inclinations (+10° and +20°) tended to increase deltoid and rotator cuff forces vs. neutral 0° inclination or inferior inclination, on the order of 20%-40% (P ≤ .045). All force metrics except anterior-posterior shear were lowest for inferior inclination. Most aTSA muscle forces for neutral 0° inclination were not significantly different from native shoulders and decreased 45% and 15% in the posterior deltoid and supraspinatus, respectively (P ≤ .003). Joint translations were similar to prior reports in aTSA patients and did not differ between any inclinations or compared with native shoulders. Joint reaction forces were similar to those observed in human subjects with instrumented aTSA implants, providing confidence in the relative magnitude of our results. CONCLUSIONS Inferior inclination reduces overall forces in the shoulder. Superior inclinations increase the muscle effort required for the shoulder to achieve similar motion, thus increasing the forces exerted on the glenoid component. These results suggest that a preference toward aTSA glenoid components in inferior inclination may reduce the likelihood of glenoid loosening by reducing excessive muscle and joint contact forces.
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Affiliation(s)
- Tyler W Knighton
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Peter N Chalmers
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Hema J Sulkar
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Klevis Aliaj
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Robert Z Tashjian
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA
| | - Heath B Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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