Glenoid Concavity Affects Anterior Shoulder Stability in an Active-Assisted Biomechanical Model.

Background: The treatment of bony glenoid defects after anteroinferior shoulder dislocation currently depends on the amount of glenoid bone loss (GBL). Recent studies have described the glenoid concavity as an essential factor for glenohumeral stability. The role of glenoid concavity in the presence of soft tissue and muscle forces is still unknown.

Additional Plate Fixation of Hinge Fractures After Varisation Distal Femoral Osteotomies Provides Favorable Torsional Stability: A Biomechanical Study.

Background: Hinge fractures are considered risk factors for delayed or nonunion of the osteotomy gap in distal femoral osteotomies (DFOs). Limited evidence exists regarding the treatment of hinge fractures after DFO, which could improve stability and thus bone healing.

Purpose: To (1) examine the effect of hinge fractures on the biomechanical properties of the bone-implant construct, (2) evaluate the biomechanical advantages of an additional fixation of a hinge fracture, and (3) test the biomechanical properties of different types of varisation DFOs.

The Long Head of the Biceps Has a Stabilizing Effect on the Glenohumeral Joint in Simulated Infraspinatus or Subscapularis but Not Supraspinatus Rotator Cuff Deficiency: A Biomechanical Study.

Purpose: To investigate the stabilizing role of the long head of the biceps (LHB) for different simulated rotator cuff (RC) tears.

Methods: Human cadaveric specimens (n = 8) were fixed in a robotic-based experimental setup with a static loading of the RC, deltoid, and the LHB. RC tears were simulated by unloading of the corresponding muscles.

The Anterior Fibers of the Superficial MCL and the ACL Restrain Anteromedial Rotatory Instability.

Background: There is limited knowledge about how the anterior cruciate ligament (ACL) and capsuloligamentous structures on the medial side of the knee act to control anteromedial rotatory knee instability.

Purpose: To investigate the contribution of the medial retinaculum, capsular structures (anteromedial capsule, deep medial collateral ligament [MCL], and posterior oblique ligament), and different fiber regions of the superficial MCL to restraining knee laxity, including anteromedial rotatory instability.

Study Design: Controlled laboratory study.

Qualitative and Quantitative Assessment of the Medial Patellar Retinaculum Anatomy: the Anteromedial Side of the Knee Revisited.

Background: In the current literature, studies on the anatomy of the anteromedial region of the knee are scarce. However, the anteromedial structures, especially the longitudinal medial patellar retinaculum (MPR), may play an important role in restraining external tibial rotation.

Purpose: To conduct a layer-by-layer dissection of the anteromedial side of the knee and describe qualitatively and quantitatively the MPR anatomy pertaining to surgically relevant landmarks.

The Biomechanical Stability of Bone Staples in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction Depends on the Implant Design.

Background: The promising biomechanical stability of bone staples (BSs) in cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction has been revealed by a previous investigation. However, it is currently unknown if the biomechanical stability of cortical fixation of tendon grafts depends on the BS design.

Purpose: To assess the biomechanical stability of cortical fixation of tendon grafts in knee surgery using 4 different BS designs.

Acromioclavicular and coracoclavicular ligamentous insertion distances depend on the scapular tilt and decrease with anterior direction of the inferior scapula angle.

Purpose: A variety of reconstruction techniques exist for the operative treatment of a ruptured acromioclavicular and coracoclavicular ligamentous complex. However, the complication rate remains high; between 5 and 89%. The intraoperative distance between the clavicle, acromion and coracoid is important for the refixation quality.

The Control of Anteromedial Rotatory Instability Is Improved With Combined Flat sMCL and Anteromedial Reconstruction.

Background: Both the superficial medial collateral ligament (sMCL) and the deep MCL (dMCL) contribute to the restraint of anteromedial (AM) rotatory instability (AMRI). Previous studies have not investigated how MCL reconstructions control AMRI.

Purpose/hypothesis: The purpose was to establish the optimal medial reconstruction for restoring normal knee kinematics in an sMCL- and dMCL-deficient knee.

Biomechanical Analysis of Coracoid Stability After Coracoplasty: How Low Can You Go?

Background: Arthroscopic coracoplasty is a procedure for patients affected by subcoracoid impingement. To date, there is no consensus on how much of the coracoid can be resected with an arthroscopic burr without compromising its stability.

Purpose: To determine the maximum amount of the coracoid that can be resected during arthroscopic coracoplasty without leading to coracoid fracture or avulsion of the conjoint tendon during simulated activities of daily living (ADLs).

The Glenolabral Articular Disruption Lesion Is a Biomechanical Risk Factor for Recurrent Shoulder Instability.

Purpose: To investigate the biomechanical effect of a glenolabral articular disruption (GLAD) lesion on glenohumeral laxity.

Methods: Human cadaveric glenoids ( = 10) were excised of soft tissue, including the labrum to focus on the biomechanical effects of osteochondral surfaces. Glenohumeral dislocations were performed in a robotic test setup, while displacement forces and three-dimensional morphometric properties were measured.

The Anatomy of Glenoid Concavity-Bony and Osteochondral Assessment of a Stability-Related Parameter.

Glenoid concavity is a crucial factor for glenohumeral stability. However, the distribution of this stability-related parameter has not been focused on in anatomical studies. In this retrospective study, computed tomography (CT) data and tactile measurements of = 27 human cadaveric glenoids were analyzed with respect to concavity.

The forgotten fragment: additional lesser tuberosity fixation of 4-part proximal humeral fractures-a biomechanical investigation.

Background: Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure.

Double plating is associated with higher fixation strength than single plating in osteoporotic fractures of the scapular spine: a biomechanical study.

Introduction: The number of atraumatic stress fractures of the scapular spine associated with reverse shoulder arthroplasty is increasing. At present, there is no consensus regarding the optimal treatment strategy. Due to the already weakened bone, fractures of the scapular spine require a high fixation stability.

Glenoid concavity has a higher impact on shoulder stability than the size of a bony defect.

Purpose: Surgical treatment of shoulder instability caused by anterior glenoid bone loss is based on a critical threshold of the defect size. Recent studies indicate that the glenoid concavity is essential for glenohumeral stability. However, biomechanical proof of this principle is lacking.