Biomechanical Characteristics of Glenosphere Orientation Based on Tilting Angle and Overhang Changes in Reverse Shoulder Arthroplasty.

Background: Glenoid position and inclination are important factors in protecting against scapular notching, which is the most common complication that directly affects the longevity of reverse shoulder arthroplasty (RSA). This study aimed to investigate the biomechanical characteristics of glenosphere orientation, comparing neutral tilt, inferior overhang with an eccentric glenosphere at the same placement of baseplate, and inferior tilt after 10° inferior reaming in the lower part of the glenoid in RSA. Methods: Nine cadaveric shoulders were tested with 5 combinations of customized glenoid components: a centric glenosphere was combined with a standard baseplate (group A); an eccentric glenosphere to provide 4-mm inferior overhang than the centric glenosphere was combined with a standard baseplate (group B); a centric glenosphere was combined with a wedge-shaped baseplate tilted inferiorly by 10° with the same center of rotation (group C); an eccentric glenosphere was attached to a wedge-shaped baseplate (group D); and 10° inferior reaming was performed on the lower part of the glenoid to apply 10° inferior tilt, with a centric glenosphere secured to the standard baseplate for simulation of clinical tilt (group E). Impingement-free angles for adduction, abduction, forward flexion, external rotation, and internal rotation were measured. The capability of the deltoid moment arm for abduction and forward flexion, deltoid length, and geometric analysis for adduction engagement were evaluated. Results: Compared with neutral tilt, inferior tilt at the same position showed no significant difference in impingement-free angle, moment arm capability, and deltoid length. However, group D resulted in better biomechanical properties than a central position, regardless of inferior tilt. Group E demonstrated a greater range of adduction, internal and external rotation, and higher abduction and forward flexion capability with distalization, compared to corresponding parameters for inferior tilt with a customized wedge-shaped baseplate. Conclusions: A 10° inferior tilt of the glenosphere, without changing the position of the baseplate, had no benefit in terms of the impingement-free angle and deltoid moment arm. However, an eccentric glenosphere had a significant advantage, regardless of inferior tilt. Inferior tilt through 10° inferior reaming showed better biomechanical results than neutral tilt due to the distalization effect.

The Influence of Component Design and Positioning on Soft-Tissue Tensioning and Complications in Reverse Total Shoulder Arthroplasty: A Review.

¼ Reverse total shoulder arthroplasty was designed to function in the rotator cuff deficient shoulder by adjusting the glenohumeral center of rotation (COR) to maximize deltoid function.¼ Adjustments in the COR ultimately lead to changes in resting tension of the deltoid and remaining rotator cuff, which can affect implant stability and risk of stress fracture.¼ Soft-tissue balance and complication profiles can be affected by humeral component (version, neck shaft angle, and inlay vs. onlay) and glenoid component (sagittal placement, version, inclination, and lateralization) design and application.¼ A good understanding of the effects on soft-tissue balance and complication profile is critical for surgeons to best provide optimal patient outcomes.

Arthroscopic Surgery Versus Nonoperative Treatment for Calcific Tendinitis of the Shoulder: A Retrospective Cohort Study.

BACKGROUND: Treatment options for calcific tendinitis (CT) of the shoulder remain controversial. A consensus for an operative indication for this condition is lacking. PURPOSE: To compare nonoperative versus operative treatment for shoulder CT and analyze factors affecting the prognosis after treatment. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 180 patients diagnosed with symptomatic CT between January 2017 and September 2021 were evaluated in this retrospective cohort study. There were 103 patients treated nonoperatively at our institution, which included the use of nonsteroidal anti-inflammatory drugs, acupuncture, steroid injections, extracorporeal shock wave therapy, and ultrasound-guided needle aspiration/percutaneous irrigation. However, 77 patients were treated with arthroscopic surgery after 6 months of failed nonoperative treatment. The visual analog scale (VAS) for pain, the Constant-Murley score, and imaging were used to assess and evaluate outcomes. Descriptive data, functional outcomes, and imaging findings were compared between the operative and nonoperative groups before and after propensity score matching. Additionally, prognostic factors including calcium deposit size, tendon infiltration by calcium deposits, involvement of single or multiple tendons, and occurrence of rotator cuff tears were analyzed by comparing the groups to determine their effect on treatment options and recovery. RESULTS: Magnetic resonance imaging showed that the supraspinatus tendon (66.7%) was most commonly involved, followed by the infraspinatus (42.8%) and subscapularis (21.1%) tendons. Tendon infiltration by calcium deposits was observed in 84.4% of the patients, and rotator cuff tears occurred in 30.0% of the patients. After propensity score matching, there was no significant difference in changes in the Constant-Murley score (48.1 ± 25.4 vs 49.0 ± 22.8, respectively; P = .950) and VAS score (4.9 ± 2.3 vs 4.5 ± 1.9, respectively; P = .860) between the operative and nonoperative groups at the final follow-up. However, for patients with shoulder CT and without rotator cuff tears, there was a significant difference in changes in the Constant-Murley score (52.93 ± 25.18 vs 42.13 ± 22.35, respectively; P = .012) and VAS score (5.21 ± 2.06 vs 3.81 ± 1.98, respectively; P < .001) between the operative and nonoperative groups, but the recovery time in the operative group was longer than that in the nonoperative group (86.92 ± 138.56 vs 30.42 ± 54.97 days, respectively; P = .016). The results also showed that calcium deposit size, involvement of multiple tendons, and tendon infiltration by calcium deposits did not affect the recovery time after treatment. The survival analysis showed that rotator cuff tears affected the complete recovery of shoulder function. CONCLUSION: This study demonstrated no significant difference between nonoperative and operative treatment for patients with shoulder CT, on the whole. However, for patients with shoulder CT and without rotator cuff tears, the effect of operative treatment was better than that of nonoperative treatment; yet, operative treatment was shown to prolong the recovery time. Calcium deposit size, tendon infiltration by calcium deposits, and involvement of multiple tendons did not correlate with recovery time or the recovery of function. A rotator cuff tear was the only factor affecting the complete recovery of shoulder function.

Fixation technique of biodegradable magnesium alloy suture anchor in the rotator cuff repair of the shoulder in a goat model: a technical note.

BACKGROUND: Shoulder disorders, particularly rotator cuff tears, are prevalent musculoskeletal conditions related to aging. Although the widely used suture anchor technique provides strong mechanical support to the tendon, it is associated with a risk of postoperative tendon retearing. The conventionally used titanium alloys can affect the interpretation of magnetic resonance imaging. Degradable magnesium alloys possess excellent biocompatibility, similar mechanical property to the bone, and stimulating bone formation ability from Mg2+. The purpose of this experiment was to develop innovative magnesium-based suture anchors to enhance rotator cuff repair by improving fixation materials, and to evaluate their feasibility in a goat model. METHODS: We developed fluoridized ZK60 suture anchors as the implantation material for two goats, who underwent rotator cuff repair surgery on both shoulders. Computed tomography (CT) and histological analysis were performed at 12 weeks postoperatively, and the results were compared between the magnesium and titanium alloy groups. Additionally, a hematological examination was conducted, which included assessments of red blood cells, white blood cells, platelets, coagulation function, liver function, kidney function, and magnesium ion concentration. RESULTS: The 12-week postoperative CT images showed intact MgF2 ZK60 suture anchors, effectively reconnecting the infraspinatus tendon to the humeral head. The anchors became less visible on CT scans, indicating absorption by surrounding tissues. New bone formation in the MgF2 group surpassed that in the Ti group, demonstrating superior osseointegration. The similarity between cortical bone and magnesium reduced stress-shielding and promoted bone regeneration. Histological analysis revealed successful tendon healing with MgF2 anchors, while the Ti group showed discontinuous interfaces and reduced collagen secretion. Hematological examination showed stable liver, renal function, and magnesium ion levels. CONCLUSIONS: The findings indicate that MgF2-coated suture anchors are feasible for rotator cuff repair and potentially other orthopedic applications. We hope that magnesium alloy anchors can become the solution for rotator cuff tendon repair surgery.

Neuropathy of the suprascapular and axillary nerves in rotator cuff arthropathy: a prospective electrodiagnostic study.

PURPOSE: Prevalence of axillary (AN) and/or suprascapular (SSN) neuropathy in rotator cuff tear arthropathy (RCTA) is unknown. We aimed to prospectively evaluate for preoperative neurodiagnostic abnormalities in order to determine their prevalence, location, and influence on reverse shoulder arthroplasty (RSA) outcomes. METHODS: Patients who underwent RSA for RCTA were prospectively included. An electromyography and nerve conduction study were performed pre and post-surgery. Clinical situation: VAS, Relative Constant-Murley Score (rCMS) and ROM over a minimum of two years follow-up. RESULTS: Forty patients met the inclusion criteria; mean follow-up was 28.4 months (SD 4.4). Injuries in RCTA were present in 83.9% (77.4% in AN and 45.2% in SSN). There were no differences on preoperative VAS, ROM, and rCMS between patients with and without preoperative nerve injuries. Four acute postoperative neurological injuries were registered under chronic preoperative injuries. Six months after RSA, 69% of preoperative neuropathies had improved (82.14% chronic injuries and 77.7% disuse injuries). No differences in improvement between disuse and chronic injuries were found, but patients with preoperative neuropathy that had not improved at the postoperative electromyographic study at six months, scored worse on the VAS (1.44 vs 2.66; p .14) and rCMS (91.6 vs 89.04; p .27). CONCLUSIONS: The frequency of axillary and suprascapular neuropathies in RCTA is much higher than expected. Most of these injuries improve after surgery, with almost complete neurophysiological recovery and little functional impact on RSA. However, those patients with preoperative neuropathies and absence of neurophysiological improvement six months after surgery have lower functional results.

Proximal Humerus Reconstruction for Bone Sarcomas: A Critical Analysis.

¼ The proximal humerus is a common location for primary bone tumors, and the goal of surgical care is to obtain a negative margin resection and subsequent reconstruction of the proximal humerus to allow for shoulder function.¼ The current evidence supports the use of reverse total shoulder arthroplasty over hemiarthroplasty when reconstructing the proximal humerus after resection of a bone sarcoma if the axillary nerve can be preserved.¼ There is a lack of high-quality data comparing allograft prosthetic composite (APC) with endoprosthetic reconstruction of the proximal humerus.¼ Reverse APC should be performed using an allograft with donor rotator cuff to allow for soft-tissue repair of the donor and host rotator cuff, leading to improvements in shoulder motion compared with an endoprosthesis.

Posterior deltoid-sparing approach for displaced inferior or posterior glenoid fossa fractures: technical note and case series.

Scapular surgery has usually been performed through the posterior Judet approach. This approach allows access to the entire posterior scapular body, but causes significant soft tissue damage and detaches the deltoid muscle. To date, there has been no clinical study of a deltoid-preserving approach to access the joint for displaced postero-inferior glenoid fractures (Ideberg type II or Ib). We describe an easy and less invasive approach to the postero-inferior glenoid fossa.

Anatomic Total Shoulder: Predictors of Excellent Outcomes at Five Years after Arthroplasty.

PURPOSE: The objectives of this study were to: report minimum 5-year outcomes in patients undergoing TSA and determine characteristics predictive of patients achieving an excellent functional outcome. METHODS: Pre-operative demographic variables and Simple Shoulder Test (SST) scores were obtained pre-operatively and at a minimum of five years after surgery. A final SST ≥ 10 and percentage of maximal possible improvement (% MPI) of ≥ 66.7% were determined to be the thresholds for excellent outcomes. Univariate and multivariate analysis were performed to identify factors associated with excellent five year clinical outcomes. RESULTS: Of 233 eligible patients, 188 (81%) had adequate follow-up for inclusion in this study. Mean SST scores improved from 3.4 ± 2.4 to 9.7 ± 2.2 (p < 0.001). Male sex was an independent predictor of both SST ≥ 10 (OR 3.46, 95% CI 1.70-7.31; p < 0.001) and %MPI ≥ 66.7 (OR 2.27, 95% CI 1.11-4.81, p = 0.027). Workers' Compensation insurance was predictive of not obtaining SST ≥ 10 (OR 0.12, 95% 0.02-0.60; p = 0.016) or %MPI ≥ 66.7 (OR 0.16, 95% CI 0.03-0.77, p = 0.025). MCID was passed by the vast majority (95%) of patients undergoing TSA and did not necessarily indicate an excellent, satisfactory outcome. CONCLUSION: Male sex and commercial insurance coverage were significantly associated with these excellent outcomes, while Workers' Compensation insurance was associated with failure to achieve this result. Thresholds for excellent outcomes, such as final SST ≥ 10 and %MPI ≥ 66.7, may be useful in identifying the characteristics of patients who benefit most from TSA.

Técnica de Latarjet para la inestabilidad anterior de hombro: implicaciones en la inervación del músculo subescapular / Latarjet procedure for shoulder instability: Implications in the innervation of the subscapularis muscle

Introducción: El objetivo de este estudio es analizar la relación existente entre la inervación del músculo subescapular y los pasos quirúrgicos de la técnica de Latarjet. Material y método: Se realizó un estudio anatómico mediante disección de 12 hombros fijados en formol, y se analizó el patrón de inervación del músculo subescapular. Se midió el tamaño del tendón en la interlínea articular, la distancia craneocaudal desde el borde superior al borde inferior del subescapular, en la entrada de los nervios, y la distancia mediolateral, desde los nervios hasta la interlínea articular. Se realizó la técnica de Latarjet y se midieron las distancias horizontales de los nervios subescapulares a la interlínea articular y de los nervios a la división del subescapular. Se describió la zona de seguridad por la que transcurre la división del subescapular sin dañar los nervios. Resultados: El músculo subescapular está inervado por 3 ramas del nervio subescapular: superior, medio e inferior, que siguen una distribución constante. No se encontraron diferencias estadísticamente significativas en las distancias de los nervios medidas antes y después de la técnica de Latarjet. Para evitar lesionar los nervios, es preciso realizar la división del subescapular entre los dos tercios superiores y el tercio inferior a lo largo del músculo. Conclusión: El músculo subescapular presenta una triple inervación constante. No hemos apreciado cambios estadísticamente significativos en la inervación tras la cirugía de Latarjet. Por tanto, la técnica de Latarjet parece respetar esta inervación al realizar la división del subescapular en su zona de seguridad.

Introduction: Our aim was to describe whether Latarjet's technique affects subscapularis muscle innervation. Materials and methods: We studied 12 embalmed shoulders. Subscapularis muscle innervation pattern was registered. Dimensions of the subscapularis at the glenohumeral joint line and the nerves entry point were measured. Horizontal distances from the nerves to the glenohumeral joint line as well as vertical ones to the split were measured before and after Latarjet procedure. A safe zone for the split was designed to avoid damage to subscapularis innervation. Results: Subscapularis muscle is innervated by three principal branches: upper, middle, and inferior subscapularis nerves. No statistical differences were found between innervation distances before and after Latarjet procedure. To perform subscapularis split along the muscle safe zone, two thirds’ proportions throughout all the split must be maintained. Conclusions: Subscapularis muscle has a triple innervation and was not altered after Latarjet procedure. Therefore, Latarjet technique seems to respect subscapularis muscle innervation if its split is placed through the subscapularis muscle safe zone.(AU)

[Translated article] Latarjet procedure for shoulder instability: Implications in the innervation of the subscapularis muscle / Técnica de Latarjet para la inestabilidad anterior de hombro: implicaciones en la inervación del músculo subescapular

Introducción: El objetivo de este estudio es analizar la relación existente entre la inervación del músculo subescapular y los pasos quirúrgicos de la técnica de Latarjet. Material y método: Se realizó un estudio anatómico mediante disección de 12 hombros fijados en formol, y se analizó el patrón de inervación del músculo subescapular. Se midió el tamaño del tendón en la interlínea articular, la distancia craneocaudal desde el borde superior al borde inferior del subescapular, en la entrada de los nervios, y la distancia mediolateral, desde los nervios hasta la interlínea articular. Se realizó la técnica de Latarjet y se midieron las distancias horizontales de los nervios subescapulares a la interlínea articular y de los nervios a la división del subescapular. Se describió la zona de seguridad por la que transcurre la división del subescapular sin dañar los nervios. Resultados: El músculo subescapular está inervado por 3 ramas del nervio subescapular: superior, medio e inferior, que siguen una distribución constante. No se encontraron diferencias estadísticamente significativas en las distancias de los nervios medidas antes y después de la técnica de Latarjet. Para evitar lesionar los nervios, es preciso realizar la división del subescapular entre los dos tercios superiores y el tercio inferior a lo largo del músculo. Conclusión: El músculo subescapular presenta una triple inervación constante. No hemos apreciado cambios estadísticamente significativos en la inervación tras la cirugía de Latarjet. Por tanto, la técnica de Latarjet parece respetar esta inervación al realizar la división del subescapular en su zona de seguridad.

Introduction: Our aim was to describe whether Latarjet's technique affects subscapularis muscle innervation. Materials and methods: We studied 12 embalmed shoulders. Subscapularis muscle innervation pattern was registered. Dimensions of the subscapularis at the glenohumeral joint line and the nerves entry point were measured. Horizontal distances from the nerves to the glenohumeral joint line as well as vertical ones to the split were measured before and after Latarjet procedure. A safe zone for the split was designed to avoid damage to subscapularis innervation. Results: Subscapularis muscle is innervated by three principal branches: upper, middle, and inferior subscapularis nerves. No statistical differences were found between innervation distances before and after Latarjet procedure. To perform subscapularis split along the muscle safe zone, two thirds’ proportions throughout all the split must be maintained. Conclusions: Subscapularis muscle has a triple innervation and was not altered after Latarjet procedure. Therefore, Latarjet technique seems to respect subscapularis muscle innervation if its split is placed through the subscapularis muscle safe zone.(AU)

Eficacia del trasplante de células madre mesenquimales de lipoaspirado en el tratamiento de lesiones crónicas del manguito rotador. Modelo experimental en ratas / Efficacy of transplantation of lipoaspired mesenchymal stem cells in the treatment of chronic rotator cuff tears. Experimental model in rats

Antecedentes y objetivo: Las roturas del manguito rotador afectan aproximadamente al 30% de la población mayor de 60 años. El tratamiento quirúrgico por vía artroscópica de estas lesiones es el tratamiento de elección, sin embargo, a pesar de las mejoras técnicas de reparación el índice de rerroturas oscila entre el 11 y el 94%. Por ello, los investigadores buscan mejorar el proceso de curación biológica mediante el uso de diferentes alternativas como las células madre mesenquimales (MSC). Nuestro objetivo es evaluar la eficacia de un medicamento de terapia celular elaborado a partir de células madre alogénicas derivadas del tejido adiposo en un modelo de lesión crónica del manguito rotador en ratas. Material y método: Se creó la lesión del supraespinoso en 48 ratas para su posterior sutura a las 4 semanas. A 24 animales se les añadió las MSC en suspensión tras la sutura, y a 24 animales HypoThermosol-FRS® (HTS) como grupo control. En ambos grupos se analizó la histología (escala Åström y Rausing) y la carga máxima, desplazamiento y constante elástica del tendón supraespinoso a los 4 meses de la reparación. Resultados: No se encontraron diferencias estadísticamente significativas en la puntuación histológica comparando los tendones tratados con MSC con respecto a los tendones tratados con HTS (p=0,811) ni tampoco en los resultados de carga máxima (p=0,770), desplazamiento (p=0,852) ni constante elástica (p=0,669) del tendón en ambos grupos. Conclusiones: La adición en suspensión de células derivadas de tejido adiposo a la reparación de una lesión crónica de manguito no mejora las características histológicas ni biomecánicas del tendón suturado.(AU)

Background and aim: Rotator cuff tears emerge in approximately 30% of the population over 60 years of age. Arthroscopic surgical treatment of these lesions is the treatment of choice, however, despite the improved repair techniques, the rate of re-tears ranges between 11 and 94%. Therefore, researchers seek to improve the biological healing process through the use of different alternatives such as mesenchymal stem cells (MSCs). Our objective is to evaluate the efficacy of a Cellular Therapy Drug made from allogeneic stem cells derived from adipose tissue in a rat model of chronic rotator cuff injury. Material and methods: The supraspinatus lesion was created in 48 rats for subsequent suturing at 4 weeks. MSCs in suspension were added to 24 animals after suturing, and HypoThermosol-FRS® (HTS) to 24 animals as a control group. Histology (Åström and Rausing scale) and the maximum load, displacement and elastic constant of the supraspinatus tendon were analyzed in both groups 4 months after the repair. Results: No statistically significant differences were found in the histological score comparing the tendons treated with MSCs with respect to the tendons treated with HTS (P=.811) nor in the results of maximum load (P=.770), displacement (P=.852) or elastic constant (P=.669) of the tendon in both groups. Conclusions: The addition of adipose-derived cells in suspension to the repair of a chronic cuff injury does not improve the histology or biomechanics of the sutured tendon.(AU)

[Translated article] Efficacy of transplantation of lipoaspired mesenchymal stem cells in the treatment of chronic rotator cuff tears. Experimental model in rats / Eficacia del trasplante de células madre mesenquimales de lipoaspirado en el tratamiento de lesiones crónicas del manguito rotador. Modelo experimental en ratas

Antecedentes y objetivo: Las roturas del manguito rotador afectan aproximadamente al 30% de la población mayor de 60 años. El tratamiento quirúrgico por vía artroscópica de estas lesiones es el tratamiento de elección, sin embargo, a pesar de las mejoras técnicas de reparación el índice de rerroturas oscila entre el 11 y el 94%. Por ello, los investigadores buscan mejorar el proceso de curación biológica mediante el uso de diferentes alternativas como las células madre mesenquimales (MSC). Nuestro objetivo es evaluar la eficacia de un medicamento de terapia celular elaborado a partir de células madre alogénicas derivadas del tejido adiposo en un modelo de lesión crónica del manguito rotador en ratas. Material y método: Se creó la lesión del supraespinoso en 48 ratas para su posterior sutura a las 4 semanas. A 24 animales se les añadió las MSC en suspensión tras la sutura, y a 24 animales HypoThermosol-FRS® (HTS) como grupo control. En ambos grupos se analizó la histología (escala Åström y Rausing) y la carga máxima, desplazamiento y constante elástica del tendón supraespinoso a los 4 meses de la reparación. Resultados: No se encontraron diferencias estadísticamente significativas en la puntuación histológica comparando los tendones tratados con MSC con respecto a los tendones tratados con HTS (p=0,811) ni tampoco en los resultados de carga máxima (p=0,770), desplazamiento (p=0,852) ni constante elástica (p=0,669) del tendón en ambos grupos. Conclusiones: La adición en suspensión de células derivadas de tejido adiposo a la reparación de una lesión crónica de manguito no mejora las características histológicas ni biomecánicas del tendón suturado.(AU)

Background and aim: Rotator cuff tears emerge in approximately 30% of the population over 60 years of age. Arthroscopic surgical treatment of these lesions is the treatment of choice, however, despite the improved repair techniques, the rate of re-tears ranges between 11 and 94%. Therefore, researchers seek to improve the biological healing process through the use of different alternatives such as mesenchymal stem cells (MSCs). Our objective is to evaluate the efficacy of a Cellular Therapy Drug made from allogeneic stem cells derived from adipose tissue in a rat model of chronic rotator cuff injury. Material and methods: The supraspinatus lesion was created in 48 rats for subsequent suturing at 4 weeks. MSCs in suspension were added to 24 animals after suturing, and HypoThermosol-FRS® (HTS) to 24 animals as a control group. Histology (Åström and Rausing scale) and the maximum load, displacement and elastic constant of the supraspinatus tendon were analyzed in both groups 4 months after the repair. Results: No statistically significant differences were found in the histological score comparing the tendons treated with MSCs with respect to the tendons treated with HTS (P=.811) nor in the results of maximum load (P=.770), displacement (P=.852) or elastic constant (P=.669) of the tendon in both groups. Conclusions: The addition of adipose-derived cells in suspension to the repair of a chronic cuff injury does not improve the histology or biomechanics of the sutured tendon.(AU)

Diagnostic Evaluation of Prosthetic Joint Infections of the Shoulder: What Does the Literature Say?

The total number of patients with a total shoulder arthroplasty (TSA) is increasing, and the number of patients experiencing a (TSA) prosthetic joint infection (PJI) also will increase. It is important that physicians know how to identify signs of infection, know the common pathogens, and know how to work up a shoulder PJI. This publication reviewed the current literature about presenting signs and symptoms, common shoulder pathogens and how they differ from total knee and hip pathogens, and what images, tests, and procedures can aid in identification of infection.

Continuous Interscalene Brachial Plexus Blocks: An Anatomical Challenge between Scylla and Charybdis?

Brachial plexus blocks at the interscalene level are frequently chosen by physicians and recommended by textbooks for providing regional anesthesia and analgesia to patients scheduled for shoulder surgery. Published data concerning interscalene single-injection or continuous brachial plexus blocks report good analgesic effects. The principle of interscalene catheters is to extend analgesia beyond the duration of the local anesthetic's effect through continuous infusion, as opposed to a single injection. However, in addition to the recognized beneficial effects of interscalene blocks, whether administered as a single injection or through a catheter, there have been reports of consequences ranging from minor side effects to severe, life-threatening complications. Both can be simply explained by direct mispuncture, as well as undesired local anesthetic spread or misplaced catheters. In particular, catheters pose a high risk when advanced or placed uncontrollably, a fact confirmed by reports of fatal outcomes. Secondary catheter dislocations explain side effects or loss of effectiveness that may occur hours or days after the initial correct function has been observed. From an anatomical and physiological perspective, this appears logical: the catheter tip must be placed near the plexus in an anatomically tight and confined space. Thus, the catheter's position may be altered with the movement of the neck or shoulder, e.g., during physiotherapy. The safe use of interscalene catheters is therefore a balance between high analgesia quality and the control of side effects and complications, much like the passage between Scylla and Charybdis. We are convinced that the anatomical basis crucial for the brachial plexus block procedure at the interscalene level is not sufficiently depicted in the common regional anesthesia literature or textbooks. We would like to provide a comprehensive anatomical survey of the lateral neck, with special attention paid to the safe placement of interscalene catheters.

Poor clinical outcomes and high rates of dislocation after modular reverse shoulder arthroplasty for proximal humeral oncologic resection.

PURPOSE: The shoulder is the most common site for upper extremity tumors. The aim of the study was to analyze the outcomes and the complications of modular reverse shoulder arthroplasty (RSA) after proximal humerus resection. METHODS: We retrospectively included 15 consecutive patients who underwent a modular MUTARS™ RSA reconstruction after proximal humerus tumour resection between 2017 and 2020. The mean age was 52 years. Their clinical outcomes were assessed using the Constant-Murley score and the MSTS shoulder. Radiological outcomes were assessed based on the presence of loosening, osteolysis, and scapular notching. Complications such as dislocation, oncological recurrence, and infection were assessed. Mean follow-up time was 32.9 months (24 to 45). RESULTS: The mean adjusted Constant score was 50.7% (min 22, max 81), and the mean MSTS score was 15.6 (min 4, max 26). We had no loosening, osteolysis, or scapular notching on the radiographs at last follow-up. We had a high complication rate of 53%: one infection, one oncological recurrence, and six dislocations (40%), of which five were re-operated. CONCLUSION: In our experience, the MUTARS™ Implantcast™ modular RSA has poor functional results and a high rate of dislocation in the case of large proximal humerus resections below the distal insertion of the deltoid.

Long head of the biceps tendon versatility in reconstructive shoulder surgery: a narrative review of arthroscopic techniques and their biomechanical principles with video presentation.

The management of the long head of the biceps tendon (LHBT) during shoulder arthroscopy has been a subject of controversy for many years, with evolving discussions and trends. Despite long-standing debate, the nature of the surgical indication regarding how to treat concomitent LHBT injuries has undergone changes in recent years. It now extends beyond the timing of tenotomy to encompass considerations of alternative methods for preserving the LHBT, along with an ongoing exploration of how it can be effectively utilized in reconstructive shoulder surgery. Recent techniques describe approaches to using LHBT in a wide range of procedures, from shoulder instability to rotator cuff tears. Additionally, LHBT-based reconstructive techniques have surfaced for addressing what were formerly denoted as irreparable rotator cuff tears. While current literature provides detailed anatomical descriptions of the LHBT and many reports of novel, advanced techniques, there is still much debate regarding the decision-making process in each case. Because of the growing number of emerging techniques and the escalating debate in the subsequent paper, a decision has been made to present the current literature review concerning the potential utilization of LHBT in shoulder arthroscopy. In a dedicated video, we demonstrate the main arthroscopic techniques employed by the authors in their daily practice.

Comparison of the incidence of inadvertent perioperative hypothermia between general anesthesia and interscalene brachial plexus block in shoulder arthroscopy: A randomized prospective study.

INTRODUCTION: Inadvertent perioperative hypothermia (IPH), defined as core body temperature below 36°C, is associated with various complications. Shoulder arthroscopy is a risk factor of IPH. This study aimed to compare the incidence of IPH between general anesthesia (GA) and interscalene brachial plexus block (ISBPB) for shoulder arthroscopy. METHOD: Patients scheduled for shoulder arthroscopy were prospectively enrolled and randomly assigned to GA or ISBPB groups. The body temperature of the patients was measured from baseline to the end of anesthesia and in the post-anesthetic care unit to compare the incidence of IPH. RESULTS: Of the 114 patients initially identified, 80 were included in the study (GA = 40, ISBPB = 40). The incidence of IPH differed significantly between the groups, with GA at 52.5% and ISBPB at 30.0% (P = .04). Profound IPH (defined as < 35.0°C) occurred in 2 patients with GA. Upon arrival at the post-anesthesia care unit, the GA group exhibited a significantly lower mean body temperature (35.9 ±â€…0.6°C) than the ISBPB group (36.1 ±â€…0.2°C, P = .04). CONCLUSION: The incidence of IPH in the GA group was higher than that in the ISBPB group during shoulder arthroscopy, suggesting that ISBPB may be a preferable anesthetic technique for reducing risk of IPH in such procedures.

[Preliminary application of foldable pedicled latissimus dorsi myocutaneous flap for repairing soft tissue defects in shoulder and back].

Objective: To explore the feasibility and effectiveness of a foldable pedicled latissimus dorsi myocutaneous flap to repair soft tissue defects in the shoulder and back. Methods: Between August 2018 and January 2023, the foldable pedicled latissimus dorsi myocutaneous flaps were used to repair soft tissue defects in the shoulder and back of 8 patients. There were 5 males and 3 females with the age ranged from 21 to 56 years (mean, 35.4 years). Wounds were located in the shoulder in 2 cases and in the shoulder and back in 6 cases. The causes of injury were chronic infection of skin and bone exposure in 2 cases, secondary wound after extensive resection of skin and soft tissue tumor in 4 cases, and wound formation caused by traffic accident in 2 cases. Skin defect areas ranged from 14 cm×13 cm to 20 cm×16 cm. The disease duration ranged from 12 days to 1 year (median, 6.6 months). A pedicled latissimus dorsi myocutaneous flap was designed and harvested. The flap was divided into A/B flap and then were folded to repair the wound, with the donor area of the flap being pulled and sutured in one stage. Results: All 7 flaps survived, with primary wound healing. One patient suffered from distal flap necrosis and delayed healing was achieved after dressing change. The incisions of all donor sites healed by first intention. All patients were followed up 6 months to 4 years (mean, 24.7 months). The skin flap has a good appearance with no swelling in the pedicle. At last follow-up, 6 patients had no significant difference in bilateral shoulder joint motion, and 2 patients had a slight decrease in abduction range of motion compared with the healthy side. The patients' daily life were not affected, and linear scar was left in the donor site. Conclusion: The foldable pedicled latissimus dorsi myocutaneous flap is an ideal method to repair the soft tissue defect of shoulder and back with simple operation, less damage to the donor site, and quick recovery after operation.

Anterior Latissimus Dorsi Transfer for Irreparable Subscapularis Tears Improves Shoulder Kinematics in a Dynamic Biomechanical Cadaveric Shoulder Model.

BACKGROUND: In young patients with irreparable subscapularis deficiency (SSC-D) and absence of severe osteoarthritis, anterior latissimus dorsi transfer (aLDT) has been proposed as a treatment option to restore the anteroposterior muscular force couple to regain sufficient shoulder function. However, evidence regarding the biomechanical effect of an aLDT on glenohumeral kinematics remains sparse. PURPOSE/HYPOTHESIS: The purpose of this study was to investigate the effects of an aLDT on range of glenohumeral abduction motion, superior migration of the humeral head (SM), and cumulative deltoid force (cDF) in a simulated SSC-D model using a dynamic shoulder model. It was hypothesized that an aLDT would restore native shoulder kinematics by reestablishing the insufficient anteroposterior force couple. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric shoulders were tested using a validated shoulder simulator. Glenohumeral abduction angle (gAA), SM, and cDF were compared across 3 conditions: (1) native, (2) SSC-D, and (3) aLDT. gAA and SM were measured using 3-dimensional motion tracking, while cDF was recorded in real time during dynamic abduction motion by load cells connected to actuators. RESULTS: The SSC-D significantly decreased gAA (Δ-9.8°; 95% CI, -14.1° to -5.5°; P < .001) and showed a significant increase in SM (Δ2.0 mm; 95% CI, 0.9 to 3.1 mm; P = .003), while cDF was similar (Δ7.8 N; 95% CI, -9.2 to 24.7 N; P = .586) when compared with the native state. Performing an aLDT resulted in a significantly increased gAA (Δ3.8°; 95% CI, 1.8° to 5.7°; P < .001), while cDF (Δ-36.1 N; 95% CI, -48.7 to -23.7 N; P < .001) was significantly reduced compared with the SSC-D. For the aLDT, no anterior subluxation was observed. However, the aLDT was not able to restore native gAA (Δ-6.1°; 95% CI, -8.9° to -3.2°; P < .001). CONCLUSION: In this cadaveric study, performing an aLDT for an irreparable subscapularis insufficiency restored the anteroposterior force couple and prevented superior and anterior humeral head migration, thus improving glenohumeral kinematics. Furthermore, compensatory deltoid forces were reduced by performing an aLDT. CLINICAL RELEVANCE: Given the favorable effect of the aLDT on shoulder kinematics in this dynamic shoulder model, performing an aLDT may be considered as a treatment option in patients with irreparable SSC-D.