The Global Track Concept for Assessment of Engaging Hill-Sachs Defects in Anterior Shoulder Instability.

BACKGROUND: The glenoid track concept is used to determine preoperatively whether a Hill-Sachs defect is engaging or not. Currently, the glenoid track concept relies on measurements of bony structures as well as on the confines and elasticity of the rotator cuff as a reference point, which varies extensively among individuals and therefore limits the reliability and accuracy of this concept. PURPOSE: To evaluate the reliability of the global track concept, which determines the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head as a new reference point with the help of an automated image analysis software and 3-dimensional analysis of the humeral head. STUDY DESIGN: Controlled laboratory study. METHODS: Computed tomography scans of 100 patients treated for anterior shoulder instability with different sizes of Hill-Sachs defects were evaluated manually by 2 orthopaedic surgeons independently using the software OsiriX as well as automatically by using a dedicated prototype software (ImFusion). Obtained manual and automated measurements included the Hill-Sachs length, Hill-Sachs width, and Hill-Sachs depth of the defect; the Hill-Sachs interval (HSI); and the glenoid width for the glenoid track concept, as well as the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head (global track concept). The reliability of the different measurement techniques was compared by calculating intraclass correlation coefficients (ICCs). RESULTS: There was a significant difference for all obtained parameters comparing manual and automatic measurements. For manually obtained parameters, measurements referring to bony boundaries (glenoid width, Hill-Sachs length, and Hill-Sachs width) showed good to excellent agreement (ICC, 0.86, 0.82, and 0.62, respectively), while measurements referring to soft tissue boundaries (HSI and glenoid track; ICC, 0.56 and 0.53, respectively) or not directly identifiable reference points (center of articular surface and global track) only showed fair reliability (ICC middle excursion, 0.42). When the same parameters were measured with the help of an automated software, good reliability for the glenoid track concept and excellent reliability for the global track concept in the middle excursion were achieved. CONCLUSION: The present study showed that the more complex global track measurements of humeral defects are more reliable than the current standard HSI and glenoid track measurements. However, this is only true when automated software is used to perform the measurements. CLINICAL RELEVANCE: Future studies using the new proposed method in combination with an automated software need to be conducted to determine critical threshold values for defects prone to engagement.

Concomitant Glenohumeral Pathologies in Patients with Acromioclavicular Joint Dislocations: How Do Acute and Chronic Instabilities Differ?

Background: Concomitant glenohumeral pathologies may be present in patients with acromioclavicular joint (ACJ) dislocations. This study aims to record and compare the prevalence and treatment of CGP in cases with acute and chronic ACJ dislocations. Methods: This retrospective cross-sectional binational, bicentric study included patients that underwent arthroscopically assisted stabilization for acute (group A) and chronic (group C) ACJ dislocations. Intraoperatively, CGPs and eventual treatments (debridement and reconstructive measures) were recorded. Results: The study included 540 patients (87% men; mean age 39.4 years), with 410 (75.9%) patients in group A and 130 (24.1%) in group C. Patients in group C were older (p < 0.001). The CGP prevalence was 30.7%, without a difference between groups A and C (p = 0.19). Supraspinatus tendon (SSP) and labral lesions were most common. Within group C, CGPs were more prevalent in surgery-naïve patients (p = 0.002). Among 49 patients with previous surgical treatment, CGPs tended to be more common in patients with prior open surgery than arthroscopically assisted surgery (p = 0.392). Increased CGP prevalence was associated with higher age (r = 0.97; p = 0.004) (up to 63% in the oldest age group, but also 17% for youngest age group) and higher in cases with Rockwood type-IIIB injuries compared to type-V injuries (p = 0.028), but type-IIIB injuries included more group C cases (p < 0.001). The most frequently found CGPs were treated by debridement rather than reconstructive interventions (SSP and labrum: p < 0.001, respectively). Conclusions: This study shows that one in three patients with ACJ instabilities has a CGP, especially elderly patients. Most of the CGPs were treated by debridement rather than constructive interventions.

Differences in Osseous Shoulder Morphology, Scapulothoracic Orientation, and Muscle Volume in Patients With Constitutional Static Posterior Shoulder Instability (Type C1) Compared With Healthy Controls.

BACKGROUND: Constitutional static posterior humeral decentering (type C1 according to ABC Classification) has been recognized as a pre-osteoarthritic deformity that may lead to early-onset posterior decentering osteoarthritis at a young age. Therefore, it is important to identify possible associations of this pathologic shoulder condition to find more effective treatment options. PURPOSE: To perform a comprehensive analysis of all parameters reported to be associated with a C1 shoulder-including the osseous shoulder morphology, scapulothoracic orientation, and the muscle volume of the shoulder girdle in a single patient cohort. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective, comparative study was conducted analyzing 17 C1 shoulders in 10 patients who underwent magnetic resonance imaging (MRI) with the complete depiction of the trunk from the base of the skull to the iliac crest, including both humeri. The mean age of the patients was 33.5 years, and all patients were men. To measure and compare the osseous shoulder morphology (glenoid version, glenoid offset, humeral torsion, anterior acromial coverage, posterior acromial coverage, posterior acromial height, and posterior acromial tilt) and scapulothoracic orientation (scapular protraction, scapular internal rotation, scapular upward rotation, scapular translation, scapular tilt, and thoracic kyphosis), these patients were matched 1 to 4 according their age, sex, and affected side with shoulder-healthy patients who had received positron emission tomography (PET)-computed tomography. To measure and compare the muscle volume of the shoulder girdle (subscapularis, infraspinatus/teres minor, supraspinatus, trapezius, deltoid, latissimus dorsi/teres major, pectoralis major, and pectoralis minor), patients were matched 1 to 2 with patients who had received PET-MRI. Patients with visible pathologies of the upper extremities were excluded. RESULTS: The C1 group had a significantly higher glenoid retroversion, increased anterior glenoid offset, reduced humeral retrotorsion, increased anterior acromial coverage, reduced posterior acromial coverage, increased posterior acromial height, and increased posterior acromial tilt compared with controls (P < .05). Decreased humeral retrotorsion showed significant correlation with higher glenoid retroversion (r = -0.742; P < .001) and higher anterior glenoid offset (r = -0.757; P < .001). Significant differences were found regarding less scapular upward rotation, less scapular tilt, and less thoracic kyphosis in the C1 group (P < .05). The muscle volume of the trapezius and deltoid was significantly higher in the C1 group (P < .05). CONCLUSION: Patients with C1 shoulders differ from healthy controls regarding osseous scapular and humeral morphology, scapulothoracic orientation, and shoulder girdle muscle distribution. These differences may be crucial in understanding the delicate balance of glenohumeral centering.

The latissimus dorsi creates a dynamic track for the inferior angle of the scapula during arm abduction in humans.

BACKGROUND: The importance of several scapulothoracic muscles, including trapezius and serratus anterior, in maintaining physiological scapula kinematics has been highlighted in the past. However, the relationship between the scapula and the latissimus dorsi muscle remains unclear. Our clinical surgical observation is that the latissimus dorsi does not directly attach but rather runs superficial to the inferior angle of the scapula. Based on this observation, we hypothesise that the latissimus dorsi creates a dynamic track on which the scapula glides under the muscle belly during elevation of the arm, creating the latissimus-scapula overlap (LSO). METHODS: All consecutive patients who had a whole-body computed tomography scan (CT) in case of polytrauma evaluation between 2018 and 2021, with complete depiction of the scapula and latissimus dorsi muscle, were analysed. 150 shoulders in 90 patients with arms up were matched according to their age (within five years), gender, and affected side with 150 shoulders in 88 patients with arms down. Patients with pathologies of the upper extremities or thorax that potentially could alter LSO measurements were excluded. LSO was calculated as a ratio of the measured area of the latissimus dorsi projection on the scapula and the total scapula area. RESULTS: The mean age of the 178 patients (48 females; 13 males) was 60 years. The arms-up group showed a significantly higher LSO than the arms-down group (19.9 ± 6.3% vs. 2.7 ± 2.2%; p < 0.0001). In the arms-up group, approximately one fifth of the scapula was overlapped inferiorly by the muscle belly of the latissimus dorsi, contrary to the almost non-existing LSO in the arms-down group. CONCLUSION: With arms up, humans show a significantly higher LSO in comparison to arms down indicating that the latissimus dorsi indeed creates a dynamic track on which the scapula is forced to travel during abduction of the arm. This finding of increased LSO during the elevation of the arm warrants further consideration of the role of the latissimus dorsi in scapula kinematics and potentially scapular dyskinesis. LEVEL OF EVIDENCE: Level two diagnostic study.

Scapulothoracic orientation has a significant influence on the clinical outcome after reverse total shoulder arthroplasty.

BACKGROUND: Computer simulation has indicated a significant effect of scapulothoracic orientation and posture on range of motion (ROM) after reverse total shoulder arthroplasty (RTSA). We analyzed this putative effect on the clinical and radiological outcome post-RTSA. METHODS: We retrospectively assessed 2-year follow-up data of RTSA patients treated at our clinic between 2008 and 2019. Patients were categorized into posture types A, B, and C based on an established method using scapular internal rotation on preoperative cross-sectional imaging. We compared differences in clinical ROM, pain, Subjective Shoulder Value, Constant Score, Shoulder Pain and Disability Index (SPADI), quality of life (EQ5D5L utility index) and radiological outcomes between posture types using linear regression analyses. RESULTS: Of 681 included patients, 225 had type A posture, 326 type B and 130 type C. Baseline group characteristics were comparable, although the type C group had a higher proportion of females (60% [A]; 64% [B]; 80% [C]) with lower abduction strength (0.7 kg [A]; 0.6 kg [B]; 0.3 kg [C]) and a slightly higher proportion with a Grammont design RTSA (41% [A]; 48% [B]; 54% [C]). There were significant adjusted differences in mean (±standard deviation) active flexion (A: 137±21°; B: 136±20°; C: 131±19°) and passive flexion (A: 140±19°; B: 138±19°; C: 134±18°), active (A: 127±26°; B: 125±26°; C: 117±27°) and passive abduction (A: 129±24°; B: 128±25°; C: 121±25°), SPADI (A: 81±18; B: 79±20; C: 73±23) and pain (A: 1.2±1.7; B: 1.6±2.2; C: 1.8±2.4) between posture types at 2 years (p≤0.035). A higher distalization shoulder angle was associated with better abduction in type C patients (p=0.016). Type C patients showed a trend towards a higher complication rate (3.9% vs 1.1% [A]; 3.2% [B]) (p=0.067). CONCLUSIONS: Type C posture influences the 2-year clinical outcome of RTSA patients in terms of worse flexion, abduction, SPADI and pain. Scapulothoracic orientation and posture should be considered during the patient selection process, preoperative planning and implantation of a RTSA.

Posteroinferior Glenosphere Positioning is Associated with Improved Range of Motion Following Reverse Shoulder Arthroplasty with a 135° Inlay Humeral Component and Lateralized Glenoid.

BACKGROUND: Optimal glenosphere positioning in a lateralized reverse shoulder arthroplasty (RSA) to maximize functional outcomes has yet to be clearly defined. Center of rotation (COR) measurements have largely relied on AP radiographs which allow assessment of lateralization and inferior position, but ignore scapular Y radiographs which may provide an assessment of posterior and inferior position relative to the acromion. The purpose of this study was to evaluate the COR in the sagittal plane and assess the effect of glenosphere positioning with functional outcomes utilizing a 135° inlay stem with a lateralized glenoid. METHODS: A retrospective review was performed on a prospectively maintained multicenter database on patients who underwent primary RSA from 2015-2021 with a 135° inlay stem. The COR was measured on minimum 2-year postoperative sagittal plain radiographs using a perfect-circle fit method. A perfect circle was made on the glenosphere and the center was marked. From there, four measurements were made: 1) center to the inner cortex of the coracoid, 2) center to the inner cortex of the anterior acromion, 3) center to the inner cortex of the middle acromion, 4) center to the inner cortex of the posterior acromion. Regression analysis was performed to evaluate any association between the position of the COR relative to bony landmarks with functional outcomes. RESULTS: A total of 136 RSAs met the study criteria. There was no relation with any of the distances with outcome scores (ASES, VAS). In regards to range of motion (ROM), each distance had an effect on at least one parameter. The COR to coracoid distance had the broadest association with ROM with improvements in forward flexion (FF), external rotation (ER0), and internal rotation with arm at 90° (IR90) (p = <0.001, 0.031, <0.001; respectively). The COR to coracoid distance was also the only distance to affect the final FF and IR90. For every 1 mm increase in this distance, there was a 1.8° increase in FF and 1.5° increase in IR90 (ß = 1.78; 95% CI 0.85 - 2.72, p = <0.001, ß = 1.53; 95% CI 0.65 - 2.41, p = <0.001; respectively). CONCLUSION: Evaluating the COR following RSA in the sagittal plane suggests that posteroinferior glenosphere position may improve ROM when using a 135° inlay humeral component and a lateralized glenoid.

Analysis of three different reverse shoulder arthroplasty designs for cuff tear arthropathy - the combination of lateralization and distalization provides best mobility.

BACKGROUND: The two major reverse shoulder arthroplasty (RSA) designs are the Grammont design and the lateralized design. Even if the lateralized design is biomechanically favored, the classic Grammont prosthesis continues to be used. Functional and subjective patient scores as well as implant survival described in the literature so far are comparable to the lateralized design. A pure comparison of how the RSA design influences outcome in patients has not yet been determined. The aim of this study was a comparison focused on patients with cuff tear arthropathy (CTA). METHODS: We analyzed registry data from 696 CTA patients prospectively collected between 2012 and 2020 in two specialized orthopedic centers up to 2 years post-RSA with the same follow-up time points (6,12 24 months). Complete teres minor tears were excluded. Three groups were defined: group 1 (inlay, 155° humeral inclination, 36 + 2 mm eccentric glenosphere (n = 50)), group 2 (inlay, 135° humeral inclination, 36 + 4 mm lateralized glenosphere (n = 141)) and group 3 (onlay, 145° humeral inclination, + 3 mm lateralized base plate, 36 + 2 mm eccentric glenosphere (n = 35)) We compared group differences in clinical outcomes (e.g., active and passive range of motion (ROM), abduction strength, Constant-Murley score (CS)), radiographic evaluations of prosthetic position, scapular anatomy and complications using mixed models adjusted for age and sex. RESULTS: The final analysis included 226 patients. The overall adjusted p-value of the CS for all time-points showed no significant difference (p = 0.466). Flexion of group 3 (mean, 155° (SD 13)) was higher than flexion of group 1 (mean, 142° (SD 18) and 2 (mean, 132° (SD 18) (p < 0.001). Values for abduction of group 3 (mean, 145° (SD 23)) were bigger than those of group 1 (mean, 130° (SD 22)) and group 2 (mean, 118° (SD 25)) (p < 0.001). Mean external rotation for group 3 (mean, 41° (SD 23)) and group 2 (mean, 38° (SD 17)) was larger than external rotation of group 1 (mean, 24° (SD 16)) (p < 0.001); a greater proportion of group 2 (78%) and 3 (69%) patients reached L3 level on internal rotation compared to group 1 (44%) (p = 0.003). Prosthesis position measurements were similar, but group 3 had significantly less scapular notching (14%) versus 24% (group 2) and 50% (group 1) (p = 0.001). CONCLUSIONS: Outcome scores of different RSA designs for CTA revealed comparable results. However, CTA patients with a lateralized and distalized RSA configuration were associated with achieving better flexion and abduction with less scapular notching. A better rotation was associated with either of the lateralized RSA designs in comparison with the classic Grammont prosthesis. LEVEL OF EVIDENCE: Therapeutic study, Level III.

[Reverse Shoulder Arthroplasty - Current Concepts]. / Inverse Schulterendoprothetik ­ aktueller Stand.

Due to first promising long term outcome data, reverse shoulder arthroplasty experienced an immense increase of usage during the past decade. Moreover, the initial Grammont concept has constantly been refined and adapted to current scientific findings. Therefore, clinical and radiological problems like scapular notching and postoperative instability were constantly addressed but do still remain an area of concern.This article summarises current concepts in reverse shoulder arthroplasty and gives an overview of actual indications like cuff tear arthropathy, severe osteoarthritis, proximal humerus fractures, tumours, fracture sequelae as well as revision surgery and their corresponding clinical and radiological results.

Reliability of Manual Measurements Versus Semiautomated Software for Glenoid Bone Loss Quantification in Patients With Anterior Shoulder Instability.

Background: The presence of glenoid bone defects is indicative in the choice of treatment for patients with anterior shoulder instability. In contrast to traditional linear- and area-based measurements, techniques such as the consideration of glenoid concavity have been proposed and validated. Purpose: To compare the reliability of linear (1-dimensional [1D]), area (2-dimensional [2D]), and concavity (3-dimensional [3D]) measurements to quantify glenoid bone loss performed manually and to analyze how automated measurements affect reliability. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Computed tomography images of 100 patients treated for anterior shoulder instability with differently sized glenoid defects were evaluated independently by 2 orthopaedic surgeons manually using conventional software (OsiriX; Pixmeo) as well as automatically with a dedicated prototype software program (ImFusion Suite; ImFusion). Parameters obtained included 1D (defect diameter, best-fit circle diameter), 2D (defect area, best-fit circle area), and 3D (bony shoulder stability ratio) measurements. Mean values and reliability as expressed by the intraclass correlation coefficient [ICC]) were compared between the manual and automated measurements. Results: When manually obtained, the measurements showed almost perfect agreement for 1D parameters (ICC = 0.83), substantial agreement for 2D parameters (ICC = 0.79), and moderate agreement for the 3D parameter (ICC = 0.48). When measurements were aided by automated software, the agreement between raters was almost perfect for all parameters (ICC = 0.90 for 1D, 2D, and 3D). There was a significant difference in mean values between manually versus automatically obtained measurements for 1D, 2D, and 3D parameters (P < .001 for all). Conclusion: While more advanced measurement techniques that take glenoid concavity into account are more accurate in determining the biomechanical relevance of glenoid bone loss, our study showed that the reliability of manually performed, more complex measurements was moderate.

SECEC Didier Patte Prize 2023: The ABC of Posterior Shoulder Instability.

BACKGROUND: The ABC classification has recently been proposed as a comprehensive classification system for posterior shoulder instability (PSI). The purpose of this study was to analyze the comprehensiveness as well as inter- and intra-rater reliability of the ABC classification. METHODS: In a prospective study all consecutive patients presenting with unidirectional PSI from June 2019 to June 2021 were included. No patients were excluded, leaving a consecutive series of 100 cases in 91 patients. All recorded clinical and imaging data was used to create anonymized clinical case vignettes, which were evaluated twice according to the ABC classification at the end of the recruitment period in random sequential order by four independent raters, two experienced shoulder surgeons and two orthopedic residents in order to analyze the comprehensiveness as well as inter- and intra-rater reliability of the ABC classification for posterior shoulder instability and to describe differences in characteristics among subtypes. Group A was defined as first-time singular posterior shoulder instability event less than 3 months in the past regardless of etiology and is further subdivided in Type 1 and Type 2 depending on the occurrence of a subluxation (A1) or dislocation (A2). Group B comprises recurrent dynamic PSI regardless of time since onset and is further subdivided by the cause of instability in functional (B1) and structural (B2) dynamic PSI. Group C includes chronic static PSI with posterior humeral decentering that can either be constitutional (C1) or acquired (C2). RESULTS: None of the cases was deemed unsuitable to be classified based on the proposed system by the observers. After consensus agreement between the two experts 16 cases were attributed to group A (A1: 8, A2: 8), 64 to group B (B1: 33, B2: 31), and 20 to group C (C1: 11, C2: 9). The expert raters agreed in 99% and 96% of the cases on the classification subtypes during the first and second rating (ICC: 0.998 and ICC: 0.99). The intraobserver reliability was excellent for both raters. The beginners reached the same conclusion as the consensus agreement in 94% (ICC: 0.99) and 89% of the cases (ICC: 0.97) during the first round and 94% each (ICC: 0.97) during the second round. The intraobserver reliability was excellent for both beginners. Overall, discrepancies between raters were found between groups B1 and B2 (n=14), B2 and C2 (n=4), B1 and C1 (n=1), as well as A1 and B2 (n=1). In general, each subtype shows distinctive clinical and imaging characteristics that facilitate the diagnosis. CONCLUSION: The presented ABC classification for PSI is a comprehensive classification with a high reliability and reproducibility. However, a gradual transition and potential progression between the subtypes of PSI must be considered. The reliable distinction between different subtypes of PSI based on etiology and pathomechanism provides a standardized basis for future investigations on treatment recommendation.

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon.

BACKGROUND: Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial. PURPOSE: To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects. RESULTS: From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups. CONCLUSION: Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential.

Neuromuscular Electrical Stimulation-Enhanced Physical Therapist Intervention for Functional Posterior Shoulder Instability (Type B1): A Multicenter Randomized Controlled Trial.

OBJECTIVE: Functional posterior shoulder instability (FPSI) (type B1) is a severe type of instability, mainly in teenagers and young adults, that leads to loss of function, pain, and stigmatization among peers. An experimental nonsurgical treatment protocol based on neuromuscular electrical stimulation (NMES) showed very promising early results in the treatment of FPSI. The hypothesis of this study was that NMES-enhanced physical therapy leads to better outcomes than physical therapy alone as the current gold standard of treatment in patients with FPSI. METHODS: In this multicenter randomized controlled trial, patients with FPSI were randomly allocated in a 1:1 ratio to either 6 weeks of physical therapy or 6 weeks of physical therapy with simultaneous motion-triggered NMES. Baseline scores as well as outcome scores at 6 weeks, 3 months, 6 months, and 12 months after the intervention were obtained. The predefined primary outcome of this trial was the Western Ontario Shoulder Instability Index (WOSI) at the 3-month time point. RESULTS: Forty-nine patients were randomized and eligible for the trial. The group that received physical therapy with simultaneous motion-triggered NMES showed a significantly better main outcome measurement in terms of the 3-month WOSI score (64% [SD = 16%] vs 51% [SD = 24%]). Two-thirds of the patients from the physical therapist group crossed over to the group that received physical therapy with simultaneous motion-triggered NMES due to dissatisfaction after the 3-month follow-up and showed a significant increase in their WOSI score from 49% [SD = 8%] to 67% [SD = 24%]. The frequency of instability episodes showed a significant improvement in the group that received physical therapy with simultaneous motion-triggered NMES at the 3-month follow-up and beyond, while in the physical therapist group, no significant difference was observed. CONCLUSION: The current study shows that NMES-enhanced physical therapy led to statistically significant and clinically relevant improvement in outcomes in the treatment of FPSI compared to conventional physical therapy alone-from which even patients with prior unsatisfactory results after conventional physical therapy can benefit. IMPACT: Based on the results of this study, NMES-enhanced physical therapy is an effective new treatment option for FPSI, a severe type of shoulder instability. NMES-enhanced physical therapy should be preferred over conventional physical therapy for the treatment of patients with FPSI.

Non-operative management of humeral periprosthetic fracture after stemless shoulder arthroplasty.

PURPOSE: Periprosthetic fractures around a stemless implant often involve lesser and greater tuberosities with a well-fixed implant in the metaphysis. This exposes the surgeon to unique questions and challenges as no surgical option (open reduction and internal fixation or revision to a stem) appears satisfactory to address them. Purpose of this study was to evaluate the clinical outcomes after non-operative management of periprosthetic fractures after stemless shoulder arthroplasty. METHODS: A retrospective multicenter study was conducted to identify all patients who had sustained non-operative management of a periprosthetic fracture after a stemless shoulder. Exclusion criteria were as follows: (1) intraoperative fractures and (2) implant loosening. Primary outcomes included mean Constant score and mean active range of motion. Secondary outcomes were VAS, radiological analysis, and complications. RESULTS: Nine patients were included. One was excluded due to the loss of follow-up at three months. Mean age was 79 years. At the last follow-up, no significant difference was observed between the Constant score, VAS, or the range of motion before fracture and at the last follow-up. Fracture healing did not result in any change in angulation in the frontal plane in seven cases and was responsible for a varus malunion in two cases of anatomic arthroplasty. No change in lateralization or distalization was reported. No cases of implant loosening after fracture have been observed. CONCLUSIONS: Conservative management seems to be appropriate in cases of minimally displaced fractures without implant loosening.

Position of scapula and clavicle in acute acromioclavicular joint dislocations: depressed scapula or elevated distal clavicle?

Background: Increased coracoclavicular distance due to acute acromioclavicular joint (ACJ) instability is often described as a pseudoelevation of the clavicle due to inferior hanging of the scapula, while the distal clavicle remains in its position. The aim of this study was to analyze whether the elevation of the distal clavicle, depression of the scapula, or both are associated with vertical instability and to evaluate the impact of weighted stress radiographs on the clavicle and scapular position in acute ACJ instabilities. Methods: The cohort consisted of 505 patients (f = 52, m = 453; mean age 46 years) which presented to our emergency department or outpatient clinic and treated in our institution from 2006 to 2019 displaying an acute ACJ injury. The panorama views that displayed at least two vertebraes with their spinous processes were retrospectively evaluated. Two raters assessed the panorama views twice regarding the clavicular and coracoidal angle of both sides in relation to the cervicothoracal spine and the difference in height of both clavicles and coracoids. Results: In our cohort, five types of displacement were distinguished: type A, only clavicle is elevated (N = 46); B, only scapula depressed (N = 36); C, the clavicle elevated and the scapula depressed (N = 67); D, both depressed (N = 133); and E, both elevated (N = 223). 123 patients had non-weighted radiographs and 353 patients stress views with 10 kg of axial load, whereas 29 patients had both radiological modalities. Among these 29 patients, a significant increase in coracoclavicular distance difference, clavicle, and scapula height (P < .05, respectively) was observed, when non-weighted radiographs were compared with weighted. A total of 13 shifts could be observed during the Rockwood type comparison of non-weighted radiographs with the weighted: six from Rockwood type II to III, two from type III to V, and five from type V to type III. Conclusion: Acute injury to the ACJ does not exclusively lead to a depression of the scapula or an elevated distal clavicle but rather leads to various vertical displacement combinations, however mostly to the elevation of both structures possibly due to muscle spasm and pain. Comparing both radiological modalities of the same patients, the routine use of weighted views should be questioned, since often a shift of Rockwood stage can be observed might lead to on the one hand inadequate conservative treatment for underestimated injuries however on the other hand unnecessary surgery for overestimated dislocations.

Prospective Multicenter Randomized Controlled Trial of Surgical Versus Nonsurgical Treatment for Acute Rockwood Type 3 Acromioclavicular Injury.

Background: Evidence for the superiority of surgical versus nonsurgical treatment of Rockwood type 3 acromioclavicular joint (ACJ) dislocation is still lacking. Hypothesis: It was hypothesized that surgical treatment will outperform nonsurgical treatment. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A prospective randomized trial involving 4 study centers was performed from January 1, 2011, to March 31, 2016. A total of 85 patients with acute Rockwood type 3 ACJ dislocations were allocated randomly to receive either nonsurgical or surgical treatment. A total of 70 patients were treated as allocated, and 8 patients made an early crossover from nonsurgical to surgical treatment, leaving 47 patients treated surgically and 31 patients nonsurgically. All patients were followed up longitudinally, including clinical evaluation using the Constant score and standardized radiographic evaluation, with final follow-up after 2 years. Results: At no follow-up time point was there a significant difference in Constant score between the surgically and nonsurgically treated patients. Radiographic analysis showed not only an inferior coracoclavicular distance at all follow-up points for surgical treatment but also a higher incidence of posttraumatic osteoarthritis and heterotopic ossifications, without any negative clinical correlation. With regard to complications, 1 patient (3%) in the nonsurgical group underwent secondary surgical ACJ stabilization. The revision rate after surgical treatment was 17% (P < .001). Neither primary horizontal instability nor younger age were associated with inferior clinical outcomes after nonsurgical treatment. Conclusion: Surgical treatment of ACJ Rockwood type 3 injuries did not lead to superior functional outcomes. Neither younger age nor horizontal instability were associated with inferior outcomes after nonsurgical treatment. Surgical treatment led to a slower recovery and to higher complication and revision rates. Registration: ISRCTN registry (study ID: ISRCTN92265154).

The V angle compliments radiographic assessment of acute acromioclavicular joint dislocations by differentiating between Rockwood types III versus V and by considering dynamic horizontal translation in coronal radiographs.

PURPOSE: Acromioclavicular joint (ACJ) dislocations are usually graded radiographically according to Rockwood, but differentiation between Rockwood types III and V may be ambiguous. The potentially clinically relevant horizontal instability is barely addressed in coronal radiographs. It was hypothesized that a new radiologic parameter (V angle) would complement ACJ diagnostics on anteroposterior radiographs by differentiating between cases of Rockwood III and V while also considering the aspect of dynamic horizontal translation (DHT). METHODS: Ninety-five patients with acute ACJ dislocations (Rockwood types III and V) were included retrospectively between 2017 and 2020. On anteroposterior views (weightbearing: n = 62, non-weight-bearing: n = 33), the coracoclavicular (CC) distance and the newly introduced V angle for assessing scapular orientation were measured bilaterally. This angle is referenced between the spinal column and a line crossing the superior scapular angle and the crossing point between the supraspinatus fossa and the medial base of the coracoid process, reported as the side-comparative difference (non-injured side *minus* injured side). DHT on Alexander views was divided into stable, partially unstable or completely unstable. RESULTS: The V angle on the injured side alone (mean 50.0°; 95% confidence interval (CI), 48.6°-51.3°) showed no correlation with the side-comparative CC distance [%] (r = - 0.040; n.s.). Thus, the V angle on the non-injured side was considered, displaying a normal distribution (n.s.) with a mean of 58.0° (95% CI, 56.6°-59.4°). The side-comparative V angle showed a correlation with the side-comparative CC distance (r = 0.83; p < 0.001) and was able to differentiate between Rockwood types III (4.7°; 95% CI, 3.9°-5.5°; n = 39) and V (10.3°; 95% CI, 9.7°-11.0°; n = 56) (p < 0.001). A cut-off value of 7° had a 94.6% sensitivity and an 82.1% specificity (area under curve, AUC: 0.954; 95% CI, 0.915-0.994). The side-comparative V angle was greater for cases with complete DHT (8.7°; 95% CI, 7.9°-9.5°; n = 78) than for cases with partial DHT (4.8°; 95% CI, 3.3°-6.3°; n = 16) (p < 0.001). A cut-off value of 5° showed a sensitivity of 84.6% and a specificity of 66.7% (AUC 0.824; 95% CI, 0.725-0.924). CONCLUSION: The scapular-based V angle on anteroposterior radiographs distinguishes between Rockwood types III and V as well as cases with partial or complete DHT. STUDY DESIGN: Diagnostic study. LEVEL OF EVIDENCE: Level II.

Instabilities and Osteoarthritis of the Sternoclavicular Joint. / Instabilitäten und Arthrose des Sternoklavikulargelenks.

Injury to the sternoclavicular joint (SCG) is very rare, accounting for 3% of shoulder injuries and < 1% of instabilities. Consequently, both the treatment of acute instabilities and their subsequent states (chronic instabilities/SCG arthrosis) are controversial. While treatment has so far been mostly conservative, in recent years there has been a trend towards surgical therapy.Considerable violence, such as that found in traffic accidents or contact sports, can tear the extremely stable ligaments between the medial clavicle and sternum. While anterior dislocation is easier to reduce in most cases, instability remains in up to 50% of cases. In most cases, posterior instability requires rapid reduction, particularly due to the anatomical proximity to important cardio-pulmonary structures. If this succeeds, the rate of persistent instabilities is low. For chronic instability, reconstruction/augmentation of the ligament apparatus with tendon grafts in the "Figure of 8 configuration" has proven to be the standard technique in recent years.

[Treatment strategies for traumatic anterior shoulder dislocation]. / Therapiestrategien bei traumatischer ventraler Schultererstluxation.

Anterior glenohumeral instability is the most frequent type of shoulder instability. This is often associated with labral and osseous lesions leading to recurrent instability. A detailed medical history, a physical examination and targeted diagnostic imaging are necessary to assess possible pathological soft tissue alterations as well as bony lesions of the humeral head and the glenoid bone. Early surgical treatment has been shown to reduce the risk of recurrence, especially in young active athletes, and can avoid secondary damage. Shoulder dislocations in older patients also require a detailed assessment and selection of treatment as persisting pain and limitation of movement can occur due to rotator cuff lesions and nerve injuries. The purpose of this article is to provide an overview of the currently available evidence and results regarding diagnostic considerations and conservative vs. surgical treatment and time to return to sport after treatment of a primary anterior shoulder dislocation.

Management of Acute High-Grade Acromioclavicular Joint Dislocations: Comparable Clinical and Radiological Outcomes After Bidirectional Arthroscopic-Assisted Stabilization With the Single Low-Profile Suture Button Technique Versus Double-Suture Button Technique.

PURPOSE: To compare the 2-year clinical and radiological outcomes of an arthroscopic-assisted bidirectional stabilization procedure using a single low-profile (LPSB) or double-suture button (DSB) technique with additional percutaneous acromioclavicular (AC) cerclage fixation for patients with acute high-grade AC joint dislocation. METHODS: This retrospective cohort study compared male patients aged between 18 and 56 years with acute high-grade AC joint dislocation fixed with either a LPSB or DSB technique. Patients were examined at least 24 months after surgery. Subjective Shoulder Value (SSV), Taft (TF), and Acromioclavicular Joint Instability (ACJI) scores were evaluated. Coracoclavicular difference, ossification, AC joint osteoarthritis, and dynamic posterior translation (DPT) were assessed on bilateral anteroposterior stress radiographs and modified Alexander views. The revision rate due to implant conflict and duration of surgery were reported. Group outcome differences were analyzed using standardized hypothesis tests. RESULTS: 28 patients aged 39.2 (LPSB) and 36.4 years (DSB) (P = .319; CI: -2.77-8.34) were eligible per cohort. The follow-up was 30.5 (LPSB) and 37.4 months (DSB) (P = .02; CI: -12.73-1.08). LPSB patients rated a significantly higher SSV (93.2% vs 81.9% [DSB]; P = .004). TF and ACJI scores were similar between the groups. Coracoclavicular difference markedly decreased from 12 mm to 3 mm for both cohorts (P < .001). Ossification was identified in over 85% in both cohorts (P = .160; CI -0.77-0.13) and osteoarthritis in 21.4% (LPSB) and 39.3% (DSB) (P = .150). Persistent DPT was found in around 30% for both cohorts (P = .561; CI -0.26-0.48). The revision rates were 0% (LPSB) and 7% (DSB) (P = .491). LPSB surgery was shorter (59.7 vs 71.5 mins [DSB]) (P = .011). CONCLUSIONS: The results of the LPSB and DSB techniques with additional percutaneous AC cerclage fixation showed comparable outcomes with excellent clinical and satisfactory radiological results. The assessment of the subjective patient satisfaction was in favor of the LPSB technique and no postoperative revision event was observed following this procedure. LEVEL OF EVIDENCE: Level III, retrospective comparative therapeutic trial.

Arthroscopic Posterior Capsulolabral Repair With Suture-First Versus Anchor-First Technique in Patients With Posterior Shoulder Instability (Type B2): Clinical Midterm Follow-up.

Background: Isolated soft tissue injuries of the posterior capsulolabral complex can be addressed arthroscopically, with various anchor systems available for repair. Purpose: To evaluate clinical and patient-reported outcomes after arthroscopic capsulolabral repair in patients with posterior shoulder instability (PSI) and to compare differences in outcomes between patients treated with a suture-first technique (PushLock anchor) and an anchor-first technique (FiberTak all-suture anchor). Study Design: Cohort study; Level of evidence, 3. Methods: Included were 32 patients with dynamic structural PSI (type B2 according to the ABC classification) treated with an arthroscopic posterior capsulolabral repair. After a mean follow-up time of 4.8 ± 3.4 years (range, 2-11) patients were evaluated clinically, and standardized outcome scores were obtained for the Subjective Shoulder Value (SSV), the Western Ontario Shoulder Instability Index (WOSI), Rowe, Kerlan-Jobe Orthopaedic Clinic (KJOC), patient satisfaction (0-5 [best]), and pain on a visual analog scale (VAS; 0-10 [worst]). Results: The overall satisfaction level with the outcome of the surgery was 4.6 ± 0.5 (range, 4-5). No patient suffered from instability events. The mean VAS level for pain was 0.4 ± 0.9 (range, 0-4) at rest and 1.9 ± 2.0 (range, 0-6) during motion. The mean SSV was 80 ± 17 (range, 30-100), the mean postoperative WOSI score 75% ± 19% (range, 18-98), the mean Rowe score 78 ± 20 (range, 10-100), and the mean KJOC score was 81 ± 18 (range, 40-100) for the entire cohort. There was no significant difference between the techniques with regard to range of motion, strength, or clinical outcome scores. Conclusion: Arthroscopic posterior capsulolabral repair was a satisfactory method to treat structural PSI type B2 with regard to stability, pain relief, and functional restoration. The majority of patients had good outcomes. No differences in outcomes were observed between the anchor-first and suture-first techniques.