Mitigating the Risk of Instability After Reverse Shoulder Arthroplasty: A Critical Analysis Review of Patient and Surgical Factors.

¼ Instability and dislocation after reverse shoulder arthroplasty may occur in up to 31% of patients.¼ Clinical risk factors for instability include younger age, male sex, increased body mass index, preoperative diagnosis of proximal humerus fracture or rotator cuff pathology, history of instability of the native shoulder or after surgery, and a medical history of Parkinson's disease.¼ Patients with rheumatoid arthritis and decreased proximity to the coracoid may also be at greater risk.¼ In patients at a high risk of instability, surgeons should consider a more lateralized prosthesis (particularly in patients with an incompetent rotator cuff), repairing the subscapularis (particularly when using a medialized prosthesis), and upsizing the glenosphere (>40 mm in male and 38-40 mm in female patients).¼ While potentially useful, less evidence exists for the use of a constrained liner (particularly with a lateralized glenosphere and/or in low-demand patients) and rotating the polyethylene liner posteriorly to avoid impingement.

A gender and size specific evaluation of Grammont-type inlay versus lateralizing onlay stem designs in achieving lateralization and distalization in reverse shoulder arthroplasty.

INTRODUCTION: In reverse shoulder arthroplasty (RSA) new designs enable greater amounts of lateralization to prevent instability and scapular notching and increase range of motion, however, excessive lateralization leads to stress upon the acromion that can result in scapular spine fatigue fractures. Aim of this study was to gender- and size-specifically assess the influence of glenosphere size and different humeral designs on lateralization, distalization, and bony impingement-free range of motion (ROM) in patients undergoing RSA. METHODS: Computed tomography scans from 30 osteoarthritic patients (f:15, m:15) and 20 cuff tear arthropathy patients (f:10, m:10) were used to virtually simulate RSA implantation. The efficacy of an inlay Grammont-type system vs. an onlay lateralizing system combined with different glenosphere sizes (36 mm vs. 42 mm) in achieving ROM, lateralization, and distalization was evaluated. Moreover, gender and patient's constitution were correlated to humeral size by radiologically measuring the best-fit circle of the humeral head. RESULTS: A different amount of relative lateralization was achieved in both genders using large glenospheres and onlay designs. Latter yielded a higher ROM in all planes for men and women with a 42 mm glenosphere; with the 36 mm glenosphere, an increased ROM was observed only in men. The 155° inlay design led to joint medialization only in men, whereas all designs led to lateralization in women. When adjusting the absolute amount of lateralization to humerus' size (or patient's height), regardless of implant type, women received greater relative lateralization using 36 mm glenosphere (inlay: 1%; onlay 12%) than men with 42 mm glenosphere (inlay: -3%; onlay: 8%). CONCLUSION: The relative lateralization achieved using onlay design is much higher in women than men. Small glenospheres yield greater relative lateralization in women compared to large glenospheres in men. Humeral lateralization using onlay designs should be used cautiously in women, as they lead to great relative lateralization increasing stress onto the acromion. LEVEL OF EVIDENCE: Basic Science Study, Computer Modeling.

The clinical efficacy and safety of platelet-rich plasma on frozen shoulder: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To systematically review the clinical efficacy (pain, function, quality of life) and safety of platelet-rich plasma (PRP) in the treatment of frozen shoulder through meta-analysis, and provide evidence-based medical evidence for the effectiveness of PRP in the treatment of frozen shoulder. METHODS: A search was conducted on international databases (Pubmed, Web of science, Embase) and Chinese databases (CNKI, Wanfang, VIP) to search the clinical studies on the efficacy of platelet-rich plasma in treating frozen shoulder (adhesive capsulitis/periarthritis/50 shoulder) and their corresponding references published from inception until January 2024. Thoroughly excluded literature not meeting the predetermined inclusion criteria, extracted relevant data from the literature, and input it into RevMan5.4 for meta-analysis. RESULTS: This study ultimately included 14 RCTs, with a total of 1024 patients. The results showed that PRP has significant advantages compared with control groups in VAS (mean difference (MD) =-0.38, 95% confidence interval(CI)(-0.73, -0.03), P = 0.03), UCLA (MD = 3.31, 95% CI (1.02,5.60),P = 0.005), DASH (MD = -4.94,95% CI (-9.34, -0.53),P = 0.03), SPADI (SPADI Total: MD =-16.87, 95% CI (-22.84, -10.91), P < 0.00001; SPADI Pain: MD =-5.38, 95% CI (-7.80, -2.97), P < 0.0001; SPADI Disability: MD =-11.00, 95% CI (-13.61,-8.39), P < 0.00001), and the active and passive Range of Motion (active flexion: MD = 12.70, 95% CI (7.44, 17.95), P < 0.00001; passive flexion: MD = 9.47, 95% CI(3.80, 15.14), P = 0.001; active extension: MD = 3.45, 95% CI(2.39, 4.50), P < 0.00001; active abduction: MD = 13.54, 95% CI(8.42, 18.67), P < 0.00001; passive abduction: MD = 14.26, 95% CI (5.97, 22.56), P = 0.0008; active internal rotation: MD = 5.16, 95% CI (1.84, 8.48), P = 0.002; passive internal rotation: MD = 3.65, 95% CI(1.15, 6.15), P = 0.004; active external rotation: MD = 10.50, 95% CI(5.47, 15.53), P < 0.0001; passive external rotation: MD = 6.00, 95% CI (1.82, 10.19), P = 0.005) except passive extension (MD = 2.25, 95% CI (-0.77, 5.28), P = 0.14). In terms of safety, most studies reported no adverse effects, and only one study reported common complications of joint puncture such as swelling and pain after treatment in both PRP and control groups. Previous studies have shown a risk of osteonecrosis caused by corticosteroids. Therefore, the safety of PRP treatment is more reliable. CONCLUSION: The results showed that PRP was more durable and safer than corticosteroids and other control groups in the treatment of frozen shoulder. STUDY DESIGN: Systematic review. TRIAL REGISTRATION: PROSPERO CRD42022359444, date of registration: 22-09-2022.

Functional Anatomy and Biomechanics of Shoulder Instability.

The glenohumeral joint is the least congruent and least constrained joint with a complex relationship of static and dynamic stabilizers to balance its native mobility with functional stability. In the young athlete, anterior shoulder instability is multifactorial and can be a challenge to treat, requiring a patient-specific treatment approach. Surgical decision-making must consider patient-specific factors such as age, sport activity and level, underlying ligamentous laxity, and goals for return to activity, in addition to careful scrutiny of the underlying pathology to include humeral and glenoid bone loss and surrounding scapular bone morphology.

Evaluating the Athlete with Instability from on the Field to in the Clinic.

Shoulder glenohumeral joint dislocations and subluxations are a relatively common injury among athletic populations. Evaluating the patient both on the field initially and through early recovery helps to determine the best treatment strategies and predict the natural history of each unique injury.

Decision Making of the In-season Athlete with Anterior Shoulder Instability.

In-season management of anterior shoulder instability in athletes is a complex problem. Athletes often wish to play through their current season, though recurrent instability rates are high, particularly in contact sports. Athletes are generally considered safe to return to play when they are relatively pain-free, and their strength and range of motion match the uninjured extremity. If an athlete is unable to progress toward recovering strength and range of motion, surgical management is an option, though this is often a season-ending decision.

Management of Shoulder Instability in the Overhead Athletes.

Overhead athletes with anterior, posterior, and multidirectional shoulder instability present with a wide range of symptoms, especially considering the injury mechanism and affected supportive structures. As such, the management of shoulder instability is widely variable and relies on rehabilitation, operative management, and sport-specific considerations, such as positional and seasonal demands on the athlete. Biomechanical analysis may further aid in the recovery process or serve as a predictive tool to identify an increased risk for injury.

Arthroscopic Management of the Contact Athlete with Anterior Instability.

Anterior glenohumeral instability is one of the most common injuries suffered from sport. Despite padding and conditioning, the shoulder joint remains particularly vulnerable to injury, especially in the setting of contact. The overall rate of anterior instability is reported to be 0.12 injuries per 1000 athlete exposures, although this is increased up to 0.40 to 0.51 in the contact athlete. Successful treatment requires consideration of restoring stability while minimizing loss of glenohumeral motion. Common treatment strategies involve addressing the pathology that results from anterior shoulder dislocation including labral detachment as well as bony defects to the humeral head and glenoid.

The Latarjet Procedure for Recurrent Anterior Shoulder Instability in the Contact Athlete.

In young athletes, anterior shoulder instability is a prevalent condition. Because of high-energy traumas, contact athletes often suffer recurrent instability, bone loss and postoperative recurrences. Patients younger than 20 years, symptomatic for more than 6 months, with ≥ 2 dislocations, with off-track Hill-Sachs lesion, glenoid bone loss, ALPSA lesion, Instability Severity Index Score > 3, and Glenoid Track Instability Management Score > 3 are at higher risk of failure. In cases of multiple dislocations with critical or subcritical glenoid bone loss, notably in collision and contact athletes, the Latarjet procedure is widely recognized as the treatment of choice.

Arthroscopic Management of Posterior Shoulder Instability.

Posterior shoulder instability is a distinct subcategory of shoulder instability with an incidence higher than previously reported. Pain is typically the primary complaint, with pathology due to repetitive microtrauma being more common that a specific traumatic event. If nonoperative treatment fails, arthroscopic posterior capsulolabral repair has been shown to result in excellent outcomes and return to sport, with American football players having the best outcomes and throwers being slightly less predictable. Risk factors for surgical failure include decreased glenoid bone width, rotator cuff injury, female gender, and the use of less than 3 anchors.

Biomechanics and Pathoanatomy of Posterior Shoulder Instability.

Posterior glenohumeral instability represents a wide spectrum of pathoanatomic processes. A key consideration is the interplay between the posterior capsulolabral complex and the osseous anatomy of the glenoid and humeral head. Stability is dependent upon both the presence of soft tissue pathology (eg, tears to the posteroinferior labrum or posterior band of the inferior glenohumeral ligament, glenoid bone loss, reverse Hill Sachs lesions, and pathologic glenoid retroversion or dysplasia) and dynamic stabilizing forces. This review highlights unique pathoanatomic features of posterior shoulder instability and associated biomechanics that may exist in patients with posterior glenohumeral instability.

Current Concepts in Assessment and Management of Failed Posterior Labral Repair.

Recurrent posterior shoulder instability after primary repair is uncommon, but presents a challenging clinical scenario. Most revisions in failed labral repair were associated with glenoid bone morphology related to critical bone loss, retroversion, or dysplasia. A variety of treatment options exist which include revision labral repair with or without capsular plication, glenoid osteotomy, humeral rotational osteotomy, or glenoid bone augmentation. No single technique has been shown to be superior and each technique has strengths and limitations. Therefore, thoughtful evaluation and planning is critical to address each patient's individual pathology to maximize success after revision surgery.

Rehabilitation and Return to Sport following Operative and Nonoperative Treatment of Anterior Shoulder Instability.

There has been growing interest in the rehabilitation process and timing of returning an athlete to sport following the management options for anterior shoulder instability. The purpose of this article is to review the current rehabilitation and return to sport (RTS) protocols for various nonoperative and operative management strategies following anterior shoulder instability events. When appropriate in the rehabilitation protocol, RTS testing should be criteria based, rather than time based, with a special focus given to psychological readiness in order to promote successful return to athletics and prevention of recurrent instability episodes in the future.

Comparison between arthroscopic Bankart repair versus arthroscopic Bankart/SLAP lesion repair in limited-contact athletes with type V SLAP lesion. A prospective cohort study.

PURPOSE: The aim of this study was to compare the functional outcomes, recurrence rate, range of motion (ROM) and return to sports activities between arthroscopic Bankart repair (ABR) versus arthroscopic Bankart/SLAP repair (ABR/S) in limited contact-athletes with a type V SLAP lesion in the scenario of recurrent anterior shoulder instability (RASI). Our hypothesis was that there is no difference between the two treatments. METHODS: Two groups of 45 limited-contact athletes with type V SLAP lesion were created. Group 1 underwent an arthroscopic Bankart repair, while group 2 had an arthroscopic Bankart/SLAP repair. The minimum follow-up period was 2 years. The WOSI and ASES scores were used to assess primary functional outcomes. Recurrence rate, ROM and return to sport were also evaluated. RESULTS: Significant differences were reported in the WOSI and ASES scores pre- and post-operatively in each group. There were no significant differences between the two groups (P = 0.78 and 0.43). We reported 4 recurrences (8.8 %) in group 1 and 5 (11.1 %) in group 2, with no difference between them (P = 0.62). There were no significant differences between the range of motion of each of the groups as well as between them. More than 90% of the athletes in both groups returned to their previous sporting activities. CONCLUSIONS: Limited-contact athletes with RASI who have a type V SLAP lesion as their primary diagnosis can be treated using either ABR or ABR/S with equal efficacy. Both treatment alternatives preserve athlete's function, stability, ROM and return to sport.

Effects of Sling-Suspension-Based Active Shoulder Joint Exercise on Shoulder Joint Subluxation, Pain, Muscle Strength, and Upper Limb Function in Patients with Subacute Stroke.

Background and Objectives: We investigated the effects of sling-suspension-based active shoulder joint exercise training on shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke. Materials and Methods: Twenty-eight patients with subacute stroke were randomly assigned to either the sling-suspension-based active shoulder joint exercise (SASE) group (n = 14) or the motorized upper extremity exercise (MUEE) group (n = 14). The SASE group actively performed shoulder joint flexion, extension, abduction, adduction, external and internal rotation, and horizontal abduction and adduction using a sling suspension system, whereas the MUEE group underwent an exercise program using a motorized upper extremity exercise machine. All participants underwent a 4-week intervention with 30 min of exercise once a day for 5 days a week. Additionally, both groups received general physical therapy and functional electrical stimulation for 30 min twice a day for 5 days a week. Shoulder joint subluxation was measured by radiographic examination before and after training, and pain was evaluated in the splenius, upper trapezius, and infraspinatus muscles using pressure parameters. In addition, a manual muscle tester was used to assess the muscle strength of the shoulder joint flexors, extensors, abductors, adductors, and external and internal rotators, and the Fugl-Mayer Assessment (FMA) and Manual Functional Test (MFT) were used to evaluate upper extremity function. Results: A significant group-time interaction was observed for pain, with F-values of F(1, 26) = 7.470, p < 0.011 for the splenius and F(1, 26) = 9.623, p < 0.005 for the upper trapezius. A significant time-group interaction was observed for the muscle strength of the shoulder, with F-values of F(1, 26) = 13.211, p < 0.001; F(1, 26) = 4.974, p = 0.035 and F(1, 26) = 9.674, p = 0.004 for flexors, abductors, and external rotators, respectively. A significant time-group interaction was observed in the FMA, with F-values of F(1, 26) = 13.243, p < 0.001. When comparing the interaction effects between time and group for MFT scores, a significant difference was observed, with F-values of F(1, 26) = 32.386, p < 0.001. Conclusions: This study confirmed that sling-suspension-based active shoulder joint exercises are effective in improving shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke.

Variability in musculoskeletal fatigue responses associated with repeated exposure to an occupational overhead drilling task completed on successive days.

Emerging research suggests that muscular and kinematic responses to overhead work display a high degree of variability in fatigue-related muscular and kinematics changes, both between and within individuals when evaluated across separate days. This study examined whether electromyographic (EMG), kinematic, and kinetic responses to an overhead drilling task performed until volitional fatigue were comparable to those of a repeated identical exposure of the task completed 1 week later. Surface EMG and intramuscular EMG, sampled from 7 shoulder muscles, and right upper limb kinematics and kinetics were analyzed from 15 male and 14 female participants. No significant day-to-day changes in EMG mean power frequency (MPF) were observed, though serratus anterior displayed significantly less fatigue-related increase in EMG root-mean-squared (RMS) signal amplitude on day 2. Unfatigued upper kinematics on day 2 featured an increase in thoracohumeral elevation, elbow flexion, and decrease in wrist ulnar deviation compared to unfatigued state on day 1. Fatigue-related changes in shoulder joint flexion moment that were present on day 1 were reduced on day 2, suggesting that a more efficient overhead work strategy was learned and preserved across successive days. Day-to-day changes in upper limb joint angle variability, quantified by median absolute deviation (MdAD), were joint dependent. Despite yielding a variable fatigue-related kinetic strategy on both days, kinematic and kinetic fatigue-related changes on a second day of completing an overhead drilling task suggested a potential kinematic learning effect.

Enhanced Outcomes and Safety of Reverse Shoulder Arthroplasty in Rotator Cuff Deficiency and Proximal Humerus Fractures: A 22-Patient Retrospective Analysis.

BACKGROUND Reverse shoulder arthroplasty (RSA) is an accepted treatment that provides reproducible results in the treatment of rotator cuff deficiency and proximal humerus fractures. This single-center study aimed to evaluate the outcomes from reverse shoulder arthroplasty for rotator cuff insufficiency and proximal humerus fractures in 22 patients from a single center. MATERIAL AND METHODS Twenty-two patients were included in the study. The median age of the patients was 66 years (Range: 58-95). Proximal humerus fractures were diagnosed using X-ray and CT, while rotator cuff tears were diagnosed using MRI. For the assessment of joint function, the Constant-Murley score, the American Shoulder and Elbow Surgeons (ASES), and the Disabilities of Arm, Shoulder, and Hand (DASH) scores were used as patient-reported outcome measures. Kaplan-Meier analysis was conducted to evaluate implant survival. RESULTS The mean follow-up duration was 4.05±1.2 years. Significant improvements were observed: ASES Score: Increased from 35.8±2.8 to 81.3±5.4 (p<0.001). VAS Pain Score: Decreased from 7.3±1 to 2.9±0.9 (p<0.001). DASH Score: Improved from 66.3±4.3 to 32.5±3.6 (p<0.001). Constant-Murley Score: Increased from 48.3±3.5 to 74.6±7.7 (p<0.001). Kaplan-Meier analysis estimated implant survival at 6.7 years (95% CI, 6.3-7.2). CONCLUSIONS When performed with appropriate indications, RSA yields positive results, as seen in the literature and our study. Interscalene block anesthesia, advancements in implant technology, and adherence to surgical procedures can reduce RSA complications and ensure its safe application.

Isokinetic Strength and Balance Analyses for Predicting Return to Sports After the Latarjet Procedure: A Prospective Cross-sectional Study.

BACKGROUND: Isokinetic torque in shoulder internal rotation (IR) and external rotation (ER) can be considered as potential indicators for dynamic stability of the glenohumeral joint. PURPOSE: To assess the efficacy of 4-month isokinetic testing in predicting the 6-month return-to-sports (RTS) status after Latarjet surgery, explore its correlations with testing parameters, and identify optimal thresholds to ensure a safe RTS. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The study assessed athletes who underwent the Latarjet stabilization procedure between January 2022 and June 2023. The primary outcome was RTS at 6 months after surgery. The primary examined predictors were isokinetic testing metrics at 4 months postoperatively. Secondary outcomes comprised the modified Closed Kinetic Chain Upper Extremity Stability Test (mCKCUEST) and several patient-reported outcome measures, including the Walch-Duplay score, the Western Ontario Shoulder Instability Index (WOSI), and the Shoulder Instability-Return to Sports after Injury scale. To assess the predictors, patients were divided into those who returned to any level of sports compared with those who did not return to sports. The correlation between isokinetic testing results and other outcome scores was also analyzed. RESULTS: A total of 71 patients (mean age, 27.43 ± 9.09 years) were included in the study. Of these, 23.61% did not return to sports, 38.89% returned at a lower level, and 37.50% returned to the same level. Significant rotational strength disparities were noted. Patients who did not return to sports at 6 months demonstrated inferior strength in concentric ER at 60 deg/s, concentric ER at 240 deg/s, concentric IR at 240 deg/s, and eccentric IR at 30 deg/s (P < .05). Similar trends appeared for all studied patient-reported outcome measures and the mCKCUEST (P < .05). Receiver operating characteristic analysis emphasized the significance of isokinetic testing in concentric ER at 240 deg/s (area under the curve = 0.759; P = .001; cutoff = 0.32 N·m/kg; sensitivity = 100.0%; specificity = 49.1%) and eccentric ER at 30 deg/s (area under the curve = 0.760; P = .001; cutoff = 0.51 N·m/kg; sensitivity = 94.1%; specificity = 49.1%) for RTS prediction. Additionally, ER strength moderately correlated with the Walch-Duplay score across all examined velocities (r = 0.26-0.34; P < .05). The modified WOSI score was weakly linked to ER strength at 240 deg/s and 30 deg/s (r = 0.24-0.25; P < .05) as well as moderately linked to the limb symmetry index in ER at 60 deg/s and 30 deg/s (r = 0.30-0.38; P < .05). CONCLUSION: Isokinetic testing can act as an independent predictor of successful RTS after Latarjet surgery, with concentric ER at 240 deg/s, concentric IR at 240 deg/s, eccentric ER at 30 deg/s, and eccentric IR at 30 deg/s showing the most accuracy. Strength recovery in ER was associated with better Walch-Duplay and modified WOSI scores.

Comparison of balance and proprioception of the shoulder joint in girls with and without upper cross syndrome.

INTRODUCTION: Upper cross syndrome is one of the most common disorders of the upper part of body, often associated with abnormalities of forward head, forward shoulders, elevated and protracted of scapula, and increased thoracic kyphosis. Conducting research on upper cross syndrome, especially in girls, is of highly significant, considering this issue and lack of examination of complications and consequences of this syndrome; therefore, this study aims to compare the balance and proprioception of the shoulder joint in girls with and without upper cross syndrome.Method The statistical population included two groups of 10-12-year-old female students, i.e., healthy and those with upper cross syndrome in the city of Khalkhal in Iran in 2022-2023. A total of 60 girl children were included in this study. The subjects were screened using a checker board and after quantitative evaluations of posture, they were assigned into two groups: healthy group (No. 30) and the one suffering from upper cross syndrome (No. 30). Forward head and forward shoulder angle were assessed using photography and kinovea software, kyphosis angle using Goniometer-pro app, static and dynamic balance using BESS and Y tests, also proprioception at angles of 45- and 80-degrees external rotation of the shoulder joint through photography and kinovea software. Data were analyzed through independent t-test in SPSS software version 26 at the significance level of 0.05.Results Healthy girls were in a better position in all variables of static balance (1.14 95% CI: [0.96, 1.70], p = 0.001), dynamic balance (0.81, 95% CI: [0.73,1.24], p = 0.001), proprioception of external rotation of shoulder joint at 45- (0.78, 95% CI: [0.64, 1.14], p = 0.001) and 80-degrees (0.89, 95% CI: [0.59, 1.34], p = 0.001) angles than those with upper cross syndrome.Conclusion It can be concluded that upper cross syndrome causes a decrease in balance and proprioception of the shoulder joint in female students; therefore, along with correcting the abnormalities, special attention should be paid to strengthening and improving these components. It is recommended for rehabilitation professionals to apply exercise training programs to improve the balance and proprioception and correct of the upper cross syndrome: that the strengthening of these components prevents musculoskeletal disorders.Implications for clinical practice• It is recommended for rehabilitation professionals to apply exercise training programs to improve the balance and proprioception of individual with upper cross syndrome.• It is recommended for rehabilitation professionals to apply exercise training programs to correct of the upper cross syndrome in order to prevents musculoskeletal disorders.