Background: The incidence of shoulder complaints in wheelchair users is high and the etiology is poorly understood. The goal of this study was to examine the effect of lesion level and isolated triceps muscle paresis on the internal load on the shoulder by simulation.
Methods: Kinematic and kinetic profiles from four able-bodied subjects and four subjects with tetraplegia were used as input for an inverse dynamics biomechanical model. The model was modified to simulate lesion level and triceps muscle paresis.
Findings: The simulations resulted in a significantly higher (+56%) glenohumeral contact force (P=0.037) for tetraplegic profiles than for able-bodied profiles. The model modifications to simulate lesion level only had a minor effect (+7%) on the calculated glenohumeral contact force. More simulations were successful at lower triceps force levels for tetraplegic profiles compared to able-bodied profiles (P=0.012). The muscle forces at the simulated T1 lesion were not significantly higher in tetraplegic profiles compared to able-bodied profiles.
Interpretation: The glenohumeral contact force for the tetraplegic profiles is mainly higher due to different task performance. Model modifications only have a minor effect on the calculated glenohumeral contact force. For able-bodied profiles the triceps force seems to be an important factor. The high internal load at the shoulder recommends new techniques of weight relief lifting and proper training of the arm-shoulder muscles in rehabilitation.
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http://dx.doi.org/10.1016/j.clinbiomech.2005.09.003 | DOI Listing |
Forensic Sci Med Pathol
January 2025
Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Via Irnerio 49, 40126, Bologna, Italy.
The diagnosis of septic arthritis remains challenging in the clinical setting, often leading to a suspicion for medical liability. Our purpose is to describe an unusual case of a post-mortem diagnosis of P. multocida fatal septic arthritis, in a healthy 67-year-old woman presenting with pain in the right shoulder.
View Article and Find Full Text PDFAm J Sports Med
January 2025
Harvard Medical School, Boston, Massachusetts, USA.
Background: While risk factors for recurrent instability (RI) after arthroscopic Bankart repair (ABR) for anterior glenohumeral instability (aGHI) have been well established in adult populations, there is much less evidence in pediatric and adolescent patients, despite being the most affected epidemiologic subpopulation.
Purpose: To identify the clinical, demographic, radiologic, and operative risk factors for RI after ABR for aGHI in pediatric and adolescent patients.
Study Design: Systematic review; Level of evidence, 4.
J Orthop Res
December 2024
AutoRSA Research Group, Orthopaedic Research Unit, Aarhus University Hospital, Aarhus, Denmark.
Anterior shoulder instability with glenoid bone lesion can be treated with the Eden-Hybinette procedure utilizing a tricortical iliac crest bone graft or the Latarjet procedure. This study aimed to evaluate the glenohumeral joint (GHJ) kinematics throughout an external shoulder rotation following the Eden-Hybinette and Latarjet procedures. Nine human specimens were examined with dynamic radiostereometry during a GHJ external rotation with anteriorly directed loads from 0 to 30 N.
View Article and Find Full Text PDFKnee Surg Sports Traumatol Arthrosc
December 2024
Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Purpose: To explore if recentering the humeral head could improve shoulder abduction in shoulders with irreparable massive rotator cuff tears (IMRCTs).
Methods: Nine fresh-frozen cadaveric shoulders were used to simulate the intact condition and IMRCTs as controls. Four 'recenter' interventions were then sequentially applied: subacromial interposition (SI) using 4- and 8-mm spacers and superior capsule reconstruction (SCR) using two- and four-layer fascia lata grafts.
J Shoulder Elbow Surg
December 2024
Balgrist Campus, Orthopaedic Research Center, Zurich, Switzerland.
Background: Failure rates in the management of recurrent posterior shoulder instability remain a concern. Cadaveric studies have established that posterior capsulolabral tears, glenoid retroversion, and posterior glenoid bone loss result in increased posterior humeral head translation in the setting of a posteriorly directed force. A high and flat acromion has recently been associated with posterior instability.
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