The management of irreparable rotator cuff tears in active patients without severe osteoarthritis is challenging. Retracted tears of the superior cuff result in devastating glenohumeral kinematics ...and decreased shoulder function. Surgical solutions such as superior capsular reconstruction (SCR) or tendon transfers may improve shoulder function. Regarding SCR, the superior capsule has been described as a static stabilizer allowing for the centering of the humeral head. However, some bases for SCR are based on biomechanical studies that should be regarded as time zero, absent healing, and generally oversimplified as ball-and-socket research rather than replicating complex functional shoulder kinematics. SCR may be waning in popularity. SCR using autograft may, or may not, prove effective in the long run. For now, it remains to be seen whether SCR is superior to partial repair of the rotator cuff.
The significance of psychological factors in orthopaedic surgery has long been underestimated. High psychological resilience plays an important role in achieving a positive postoperative outcome in ...terms of mental health, pain, and functional outcomes. This underscores the need for a more holistic approach to patient care, one that considers not only the physical aspects of treatment but also the emotional and psychological well-being of patients. This may involve implementing strategies to enhance resilience, providing support resources for coping with the challenges of surgery and recovery, and fostering open communication between patients and healthcare providers. Patients who feel supported and empowered throughout their surgical journey are likely to experience improved overall satisfaction with their care. Patient emotional well-being is integral to achieving optimal recovery.
There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair ...has a long history and dates back to the beginning of the twentieth century.
Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability.
Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Efficient hydrogenations of terminal alkenes with molecular hydrogen catalyzed by well‐defined bench stable Mn(I) complexes containing an N‐heterocyclic carbene‐based PCP pincer ligand are described. ...These reactions are environmentally benign and atom economic, implementing an inexpensive, earth abundant non‐precious metal catalyst. A range of aromatic and aliphatic alkenes were efficiently converted into alkanes in good to excellent yields. The hydrogenation proceeds at 100 °C with catalyst loadings of 0.25–0.5 mol %, 2.5–5 mol % base (KOtBu) and a hydrogen pressure of 20 bar. Mechanistic insight into the catalytic reaction is provided by means of DFT calculations.
Efficient hydrogenations of terminal alkenes with molecular hydrogen catalyzed by well‐defined bench stable Mn(I) complexes containing an N‐heterocyclic carbene‐based PCP pincer ligand are described.
Background:
Persistent posterior instability of the acromioclavicular (AC) joint is a reported complication after isolated coracoclavicular (CC) reconstruction. Thus, multiple techniques have been ...proposed attempting to restore biomechanics of the AC ligament complex (ACLC).
Purpose/Hypothesis:
The purpose was to evaluate the posterior translational and rotational stability of an ACLC reconstruction with a dermal allograft (ACLC patch) as compared with 3 suture brace constructs. It was hypothesized that the ACLC patch would better restore AC joint posterior stability.
Study Design:
Controlled laboratory study.
Methods:
A total of 28 cadaveric shoulders (mean ± SD age, 57.6 ± 8.3 years) were randomly assigned to 1 of 4 surgical techniques: ACLC patch, oblique brace, anterior brace, and x-frame brace. The force and torque to achieve 10 mm of posterior translation and 20° of posterior rotation of the AC joint were recorded in the following conditions: intact, transected ACLC, ACLC patch/brace repair, ACLC patch/brace repair with dissected CC ligaments, and ACLC patch/brace repair with CC ligament repair.
Results:
For posterior translation, transection of the ACLC reduced resistance to 16.7% of the native. With the native CC ligaments intact, the ACLC patch (59.1%), oblique brace (54.1%), and anterior brace (60.7%) provided significantly greater stability than the x-frame brace (33.2%; P < .001, P = .008, P < .001, respectively). ACLC patch, oblique brace, and anterior brace continued to have significantly higher posterior translational resistance than the x-frame (35.1%; P < .001, P = .003, P < .001) after transection and subsequent CC ligament repair. For posterior rotation, transection of the ACLC decreased the resistance to 5.4% of the intact state. With the CC ligaments intact, the ACLC patch (77.1%) better restored posterior rotational stability than the oblique (35.3%), anterior (48.5%), and x-frame (23.0%) brace repairs (P < .001, P = .002, P < .001). CC ligament transection and subsequent repair demonstrated the ACLC patch (41.0%) to have improved stability when compared with the oblique (16.0%), anterior (14.0%), and x-frame (12.7%) repairs (P = .006, P = .003, P = .002).
Conclusion:
ACLC reconstruction with a dermal allograft better restored native posterior rotational stability than other brace constructs, with translational stability similar to the oblique and anterior brace technique at the time of surgery.
Clinical Relevance:
Horizontal stability of the AC joint is primarily controlled by the ACLC. Inability to restore AC joint biomechanics can result in persistent posterior instability and lead to functional impairment.
Background:
In the past decade, superior capsular reconstruction has emerged as a potential surgical approach in young patients with irreparable posterosuperior rotator cuff tears (RCT) and absence ...of severe degenerative changes. Recently, the use of locally available and biological viable autografts, such as the long head of the biceps tendon (LHBT) for SCR has emerged, with promising early results.
Purpose/Hypothesis:
The purpose of this study was to investigate the effect of using the LHBT for reconstruction of the superior capsule on shoulder kinematics, along with different fixation constructs in a dynamic biomechanical model. The authors hypothesized that each of the 3 proposed fixation techniques would restore native joint kinematics, including glenohumeral superior translation (ghST), maximum abduction angle (MAA), maximum cumulative deltoid force (cDF), and subacromial peak contact pressure (sCP).
Study Design:
Controlled laboratory study.
Methods:
Eight fresh-frozen cadaveric shoulders (mean age, 53.4 ± 14.2 years) were tested using a dynamic shoulder simulator. Each specimen underwent the following 5 conditions: (1) intact, (2) irreparable posterosuperior rotator cuff tear (psRCT), (3) V-shaped LHBT reconstruction, (4) box-shaped LHBT reconstruction, and (5) single-stranded LHBT reconstruction. MAA, ghST, cDF and sCP were assessed in each tested condition.
Results:
Each of the 3 LHBT techniques for reconstruction of the superior capsule significantly increased MAA while significantly decreasing ghST and cDF compared with the psRCT (P < .001 and P < .001, respectively). Additionally, the V-shaped and box-shaped techniques significantly decreased sCP (P = .009 and P = .016, respectively) compared with the psRCT. The V-shaped technique further showed a significantly increased MAA (P < .001, respectively) and decreased cDF (P = .042 and P = .039, respectively) when compared with the box-shaped and single-stranded techniques, as well as a significantly decreased ghST (P = .027) when compared with the box-shaped technique.
Conclusion:
In a dynamic biomechanical cadaveric model, using the LHBT for reconstruction of the superior capsule improved shoulder function by preventing superior humeral migration, decreasing deltoid forces and sCP. As such, the development of rotator cuff tear arthropathy in patients with irreparable psRCTs could potentially be delayed.
Clinical Relevance:
Using a biologically viable and locally available LHBT autograft is a cost-effective, potentially time-saving, and technically feasible alternative for reconstruction of the superior capsule, which may result in favorable outcomes in irreparable psRCTs. Moreover, each of the 3 techniques restored native shoulder biomechanics, which may help improve shoulder function by preventing superior humeral head migration and the development of rotator cuff tear arthropathy in young patients with irreparable rotator cuff tears.
Elliptical shape humeral head prostheses have been recently proposed to reflect a more anatomic shoulder replacement. However, its effect on obligate glenohumeral translation during axial rotation ...compared to a standard spherical head is still not well understood. The purpose of the study was to compare obligate humeral translation during axial rotation using spherical and elliptical shaped humeral head prostheses. It was hypothesized that the spherical head design would show significantly more obligate translation when compared to the elliptical design.
Six fresh-frozen cadaveric shoulders were utilized for biomechanical testing of internal (IR) and external (ER) rotation at various levels of abduction (0°, 30°, 45°, 60°) with lines of pull along each of the rotator cuff muscles. Each specimen underwent the following three conditions: (1) native; total shoulder arthroplasty (TSA) using (2) an elliptical and (3) spherical humeral head implant. Obligate translation during IR and ER was quantified using a 3-dimensional digitizer. The radius of curvature of the superoinferior and anteroposterior dimensions of the implants was calculated across each condition.
Posterior and inferior translation as well as compound motion of spherical and elliptical heads during ER was similar at all abduction angles (P > 0.05, respectively). Compared to the native humeral head, both implants demonstrated significantly decreased posterior translation at 45° (elliptical: P = 0.003; spherical: P = 0.004) and 60° of abduction (elliptical: P < 0.001; spherical: P < 0.001). During internal rotation at 0° abduction, the spherical head showed significantly more compound motion (P = 0.042) compared to the elliptical head. The spherical implant also demonstrated increased anterior translation and compound motion during internal rotation at 60° abduction (P < 0.001) compared to the resting state. This difference was not significant for the native or elliptical head design at this angle (P > 0.05).
In the setting of TSA, elliptical and spherical head implants showed similar obligate translation and overall compound motion during axial rotation. A gained understanding of the consequences of implant head shape in TSA may guide future surgical implant choice for better recreation of native shoulder kinematics and potentially improved patient outcomes.
Controlled Laboratory Study.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The development of all-suture anchors has revolutionized the field of orthopaedic surgery. Biomechanically, these anchors have similar or better strength when compared with conventional solid ...anchors. All-suture anchors allow the suture to be placed in cortical bone tunnels, with a smaller diameter, thus limiting potential iatrogenic damage. To avoid the inconsistencies of knot tying and eliminate knot stacks, knotless all-suture anchors have been increasingly used in arthroscopic surgery. This may reduce the potential risk of knot abrasion, which can lead to soft-tissue or cartilage damage. Depending on the intraoperative situation and surgeon preference, surgeons must decide whether knotted or knotless anchor systems are indicated.
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