Contact mechanics of reverse total shoulder arthroplasty during abduction: the effect of neck-shaft angle, humeral cup depth, and glenosphere diameter

Langohr, G. Daniel G.; Willing, Ryan; Medley, John B.; Athwal, George S.; Johnson, James A.

doi:10.1016/j.jse.2015.09.024

Cited by 62 publications

(45 citation statements)

References 29 publications

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“…In particular, the consideration of glenoid size is of high relevance for long-term osseous integration [2, 9, 10]. Recent findings showed that small baseplates improve primary stability of the glenoid component in small glenoids [9], but published data for small glenoids for example in women are limited.…”

Section: Introductionmentioning

confidence: 99%

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors

Mathews

Burkhard

Serrano

et al. 2017

BMC Musculoskelet Disord

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BackgroundPlacement of the glenoid baseplate is of paramount importance for the outcome of anatomical and reverse total shoulder arthroplasty. However, the database around glenoid size is poor, particularly regarding small scapulae, for example, in women and smaller individuals, and is derived from different methodological approaches. In this multimodality cadaver study, we systematically examined the glenoid using morphological and 3D-CT measurements.MethodsMeasurements of the glenoid and drill hole tunnel length for superior baseplate screw placement were recorded to define size of the glenoid and the distance to the scapular notch on cadaveric specimens. Glenoid angles were determined on both, 3D-CT-scans of the thoraxes using the Friedman method and on subsequently isolated scapulae from 18 male and female donors (average 84 years, range 60–98 years).ResultsMean glenoid height was 36.6 mm ± 3.6, and width 27.8 mm ± 3.1 with a significant sex dimorphism (p ≤ 0.001): in males, glenoid height 39.5 mm ± 3.5, and width 30.3 mm ± 3.3, and in females, glenoid height 34.8 mm ± 2.2, and width 26.2 mm ± 1.6. The average distance from the superior screw entry to its exit in the scapular notch measured by calliper was 27.2 mm ± 6.0 with a sex difference: in males, 29.4 mm ± 5.7, and in females, 25.8 mm ± 5.9 mm with a minimum recorded distance of 15 mm. Measured by CT, the mean inclination angle for male and female donors combined was 13.0° ± 7.0, and the ante-/retroversion angle −1.0° ± 4.0°.ConclusionThis study is one of the first to combine dissection, including drill holes, with anatomical measurements and radiological data. In some women and smaller individuals, smaller baseplates should be selected. The published safe zone of 20 mm is generally feasible for superior screw placement, however, in small patients this distance may be substantially shorter than expected and start as of 13 and 15 mm, respectively. No correlation between glenoid height or width with the length of our drilling canal towards the scapular notch was found. Preoperative CT-based treatment planning to determine version and inclination angles is recommended.

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Section: Introductionmentioning

confidence: 99%

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors

Mathews

Burkhard

Serrano

et al. 2017

BMC Musculoskelet Disord

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“…). This is likely due to a lower compressive/shear JCF ratio with lower NSA, which is supported by Langohr et al who reported that during abduction, contact patterns on the articular surface of the humeral cup were centrally located with lower NSAs and shifted inferomedially with higher NSAs. The risk of instability with lower NSA is eliminated by increasing cup depth, but requires some sacrifice in GC‐ROM (Fig.…”

Section: Discussionmentioning

confidence: 57%

“…Previous studies related to ROM of rTSA generally characterize ranges of motions that are contained within a subset of single paths (i.e., abduction, flexion, axial rotation, etc.) . However, conclusions pertaining to implant performance drawn from a subset of investigated motions may be misleading, as it has been shown that differing implant designs maximize different motions .…”

Section: Discussionmentioning

confidence: 99%

“…It should be noted that the geometries of the humeral cup and glenosphere were generic representations of the existing designs. The design parameters that were varied, as well as their values, have been commonly investigated in the previous studies, as they represent a range of commercially available designs …”

Section: Methodsmentioning

confidence: 99%

“…The design parameters that were varied, as well as their values, have been commonly investigated in the previous studies, as they represent a range of commercially available designs. 9,33,34 GC-ROM was calculated for each implant configuration by averaging ROM normalized by anatomic ROM across all IE rotation angles as previously described. In addition, the effect of varying each implant parameter on ROM at each IE rotation angle was determined by averaging normalized ROM values at a given degree of IE rotation across all configurations with the corresponding implant parameter values.…”

Section: Implant Configurationsmentioning

confidence: 99%

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Development and Application of a Novel Metric to Characterize Comprehensive Range of Motion of Reverse Total Shoulder Arthroplasty

Elwell

Athwal

Willing

2019

Journal Orthopaedic Research

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Active range of motion (ROM) of reverse total shoulder arthroplasty (rTSA) can be limited by bony impingement, muscle inability, and joint instability. The aim of this study was to develop a novel metric representative of comprehensive ROM of rTSA, which is evaluated in the context of all three factors. It was hypothesized that the metric, termed global circumduction ROM (GC‐ROM), would capture differences resulting from directional changes in rTSA design parameters known to increase ROM. GC‐ROM was calculated for a set of 18 rTSA configurations with humeral polyethylene cup depths of 6 and 8.1 mm, glenosphere lateralization (GLat) distances of 0, 5, and 10 mm, and neck‐shaft angles (NSA) of 135°, 145°, and 155°. For any implant configuration, arm positions were defined by internal/external (IE) rotation angle and two spherical coordinates representing the elevation plane angle and elevation angle. At each IE rotation angle, incremental positions with variable elevation plane and elevation angles were checked for feasibility based on impingement, muscle ability, and risk of instability. Coordinates of feasible positions were mapped to unit spheres and connected to form regions, of which the surface area was calculated to represent allowable circumduction ROM. ROMs were averaged across all IE rotation angles to produce a single metric, GC‐ROM. The results showed that decreasing cup depth and increasing GLat and NSA increased GC‐ROM. In conclusion, a novel metric to characterize comprehensive ROM, evaluated based on several ROM‐limiting factors, was developed as a performance metric through which rTSA designs can be compared. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:880‐887, 2020

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Development of a framework to assess the biomechanical impact of reverse shoulder arthroplasty placement modifications

Glenday

Sivarasu

Roche

et al. 2021

Journal Orthopaedic Research

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Reverse shoulder arthroplasty biomechanics can be improved by modifying the placement of prosthesis. Biomechanical studies have quantified the impact of placement modifications on the mobility and stability of the reverse shoulder. While these studies have provided detailed insights, direct comparisons between their finding are obfuscated by their use of differing methodologies. The aim of our study was to develop an assessment framework which used musculoskeletal simulations to consistently evaluate the biomechanics of various placement modifications. We conducted musculoskeletal simulations of humeral elevations and rotations using 15 reverse shoulder models. For each model, these simulations were conducted for a reference configuration of the prosthesis, established using surgical guidelines, and 34 modified configurations, which were based on commonplace adaptations to the placement of the glenosphere and humeral tray. The effect of each modified configuration on deltoid elongation, deltoid moment arm (DMA), joint stability, and impingement‐free range of motion (IFROM) was determined relative to the reference configuration. We found that 16 of the 34 modified placements had an overall beneficial impact on reverse shoulder biomechanics. Within this subset, we identified two biomechanical trade‐offs. First, there is an antagonistic relationship between IFROM and both the DMA and joint stability. Second, functional requirements differ between humeral elevations and rotations. Furthermore, we found that posteromedial translation of the humeral tray had the most beneficial impact on joint stability and inferior translation of the glenosphere had the most beneficial impact on IFROM and DMA.

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Contact mechanics of reverse total shoulder arthroplasty during abduction: the effect of neck-shaft angle, humeral cup depth, and glenosphere diameter

Cited by 62 publications

References 29 publications

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors

Development and Application of a Novel Metric to Characterize Comprehensive Range of Motion of Reverse Total Shoulder Arthroplasty

Development of a framework to assess the biomechanical impact of reverse shoulder arthroplasty placement modifications

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