Comparative study of two different horizontal stabilisation methods in arthroscopically assisted coracoclavicular stabilisation for acute acromioclavicular joint dislocations-Good clinical outcome and no correlation to recurrent anteroposterior instability.

PURPOSE: The hypothesis of this study was that acromioclavicular K-wire transfixation is noninferior to horizontal FiberTape cerclage in terms of vertical and horizontal stability in the short follow-up period of acute acromioclavicular joint (ACJ) dislocations fixed with an arthroscopically assisted coracoclavicular single bundle endobutton cerclage system. The secondary aim was to investigate the impact of postoperative recurrent instability on clinical outcomes in these populations. METHODS: In this consecutive clinical trial, all patients who underwent surgery for acute AC joint dislocation between January 2017 and December 2021 were included. Two groups were formed according to the additional AC stabilisation technique (K-wire group, cerclage group). Clinical examination and bilateral radiologic analysis (Zanca stress view, Alexander view) were performed with a follow-up period of at least 12 months. Satisfaction, return to sports, active range of motion, global shoulder scores and specific shoulder scores including constant score, disabilities of the arm, shoulder and hand (DASH) score and ACJ instability score (ACJI) were evaluated. Complications, including recurrent instability, and revision rate were assessed. RESULTS: Included were 59 patients (32 K-wire group, 27 cerclage group, 92% male, median follow-up 33 months). No significant differences were found in the clinical outcome parameters between the different techniques, except for the DASH value (superior in the K-wire group). Recurrent anteroposterior instability was radiographically detected in 27% of patients. No correlation was found between anteroposterior instability and clinical outcome parameters. There was no revision surgery due to chronic ACJ instability. CONCLUSION: Horizontal ACJ stabilisation with temporary K-wire transfixation does not appear to be inferior to a FiberTape cerclage technique in acute ACJ dislocations stabilised in an arthroscopically assisted single bundle DogBone technique. Recurrent ACJ instability detected radiographically does not necessarily correlate with the functional outcome and can be well compensated. LEVEL OF EVIDENCE: Level III.

Surgical treatment of fracture sequelae of the proximal humerus according to a pathology-based modification of the Boileau classification results in improved clinical outcome after shoulder arthroplasty.

BACKGROUND: Fracture sequelae of the proximal humerus were classified by Boileau into four types. Since there are pathomorphological differences and specific characteristics within the four types, we have developed a subclassification. For elderly patients, shoulder arthroplasty is mostly recommended. Based on the available literature and clinical trial results, a subclassification could be created that suggests a specific therapy for each subgroup. The aim of this study was to evaluate the endoprosthetic therapy according to the proposed subclassification and to provide an overview of the clinical and radiological results after endoprosthetic treatment of proximal humerus fracture sequelae. METHODS: Patients with fracture sequelae of the proximal humerus who underwent arthroplasty according to the suggestion of the subclassification were included. Minimum time to follow-up was twelve months. General condition and several specific shoulder scores as the Constant-Murley Score (CS) were recorded at the follow-up examination. Complication and revision rates were analyzed. RESULTS: In total, 59 patients (72.6 ± 10.0 years, 47 females, 12 males) were included. Mean follow-up time was 31.3 ± 17.0 months. Reverse shoulder arthroplasty was performed in 49 patients and anatomic shoulder arthroplasty was performed in ten patients. The CS increased by 47.3 points from preoperative (15.0) to postoperative (62.3). Good or very good clinical results were seen in 61% of the patients. Complications were observed in twelve (20%) patients and revision surgery was performed in nine (15%) patients. CONCLUSION: Due to of the variety of fracture sequelae of the proximal humerus, a modification of the Boileau classification seems necessary. This study shows that endoprosthetic treatment for fracture sequelae can significantly improve the shoulder function in elderly patients. Good clinical results can be achieved with a comparatively low revision rate following the treatment suggestions of the proposed subclassification of the Boileau classification. LEVEL OF EVIDENCE IV: Case series.

Correct positioning of the calcar screw leads to superior results in proximal humerus fractures treated with carbon-fibre-reinforced polyetheretherketone plate osteosynthesis with polyaxial locking screws.

BACKGROUND: Plate osteosynthesis with implants made of carbon-fibre-reinforced polyetheretherketone (CFR-PEEK) has recently been introduced for the treatment of fractures of the proximal humerus (PHFs). The advantages of the CFR-PEEK plate are considered to be its radiolucency, its favourable modulus of elasticity, and the polyaxial placement of the screws with high variability of the angle. The primary aim of this study is to investigate the influence of calcar screw positioning on the complication and revision rates after CFR-PEEK plating of PHFs. The secondary aim is to assess its influence on functional outcome. MATERIAL AND METHODS: Patients were identified retrospectively. Minimum follow-up was 12 months. The cohort was divided into two groups depending on the distance of the calcar screw to the calcar (group I: < 12 mm, group II: ≥ 12 mm). The range of motion (ROM), Subjective Shoulder Value Score (SSV) and Constant-Murley Score (CS) were analysed at follow-up examination. Subjective complaints, complications (e.g. humeral head necrosis, varus dislocation) and the revision rate were evaluated. RESULTS: 51 patients (33 female, 18 male) with an average age of 68.6 years were included after a period of 26.6 months (group I: 32 patients, group II: 19 patients). Apart from the gender distribution, no significant differences were seen in the patient characteristics. The outcome scores showed significantly better clinical results in group I: SSV 83.4 vs 71.2, p = 0.007; CS 79.1 vs 67.8, p = 0.013. Complications were seen less frequently in group I (18.8 % vs 47.4 %, p = 0.030). CONCLUSION: This study shows that the positioning of the calcar screw is relevant for CFR-PEEK plate osteosynthesis in PHFs with a good reduction of the fracture. Optimal positioning of the calcar screw close to the calcar (< 12 mm) is associated with a lower rate of complications, resulting in significantly superior functional outcomes. LEVEL OF EVIDENCE: III, retrospective cohort study.

Deltoid Muscle Tension Alterations Post Reverse Shoulder Arthroplasty: An Investigation Using Shear Wave Elastography.

INTRODUCTION: This study aimed to evaluate the utility of shear wave elastography (SWE) in assessing changes in deltoid muscle properties following reverse shoulder arthroplasty (RSA). METHODS: Our cohort consisted of 18 patients who underwent RSA due to various conditions, including osteoarthritis, cuff arthropathy, and irreducible proximal humeral fractures. Pre- and postoperative muscle elasticity and stiffness were measured using SWE and were compared with functional outcomes and radiological parameters. RESULTS: Our results showed significant changes in deltoid muscle elasticity after RSA, particularly in the anterior and middle portions. However, these alterations were not correlated with postoperative functional outcomes or specific radiological parameters. The study also underscored the potential of SWE for future applications, including the preoperative assessment of deltoid function, postoperative monitoring, and intraoperative use for optimal component positioning during RSA. CONCLUSION: Further research, involving larger, more homogeneous patient cohorts is needed to confirm these findings and to explore the potential influence of these changes on the biomechanical design of implants and prosthesis positioning in RSA.

Functional results and unfavorable events after treatment of proximal humerus fractures using a new locking plate system.

BACKGROUND: Proximal humerus fractures are often treated with a fixed-angle titanium plate osteosynthesis. Recently, plates made of alternative materials such as carbon fibre-reinforced polyetheretherketone (CFR-PEEK) have been introduced. This study presents the postoperative results of patients treated with a CFR-PEEK plate. METHODS: Patients with proximal humerus fractures treated with a CFR-PEEK plate (PEEKPower™ Humeral Fracture Plate (HFP)) were included. In follow-up examination, age and gender adjusted Constant-Murley Score (ACS), Subjective Shoulder Value (SSV), Quick Disabilities of the Arm, Shoulder and Hand Score (QDASH) and pain score (Visual Analog Scale (VAS)) were analyzed. General condition at follow-up was measured by European Quality of Life 5 Dimensions 3 Level Version (EQ-5D-3L). Range of motion was recorded. In addition, radiographs at follow-up, unfavorable events and revision rate were analyzed. RESULTS: In total, 98 patients (66.0 ± 13.2 years, 74 females, 24 males) were reexamined. Mean follow-up was 27.6 ± 13.2 months. There were 15 2-part, 28 3-part and 55 4-part fractures. The functional scores showed good results: SSV 83.3 ± 15.6%, QDASH 13.1 ± 17.0 and ACS 80.4 ± 16.0. A 4-part-fracture, head split component, nonanatomic head shaft reposition and preoperative radiological signs of osteoarthritis were significant negative predictors for poorer clinical scores. Unfavourable events were observed in 27 patients (27.6%). Revision surgery was performed in 8 (8.2%) patients. Risk factors for an unfavourable event were female gender, age of 50 years and older, diabetes, affected dominant hand, 4-part fracture, head split and preoperative radiological signs of osteoarthritis. CONCLUSION: There are several advantages of the CFR-PEEK plate (PEEKPower™ Humeral Fracture Plate (HFP)) such as the polyaxial screw placement and higher stability of locking screws. In summary, the CFR-PEEK plate osteosynthesis is a good alternative with comparable clinical results and some biomechanical advantages. Proximal humerus fractures show good clinical results after treatment with a CFR-PEEK plate. The revision rate and the risk of unfavorable events are not increased compared to conventional titanium plate osteosynthesis. LEVEL OF EVIDENCE: IV.

Twin Robotic Gantry-Free Cone-Beam CT in Acute Elbow Trauma.

Background Posttraumatic CT imaging of the elbow can be challenging when patient mobility is limited. Gantry-free cone-beam CT (CBCT) with a twin robotic radiography system offers greater degrees of positioning freedom for three-dimensional elbow scans over gantry-based multidetector CT (MDCT), but studies analyzing their clinical value remain lacking. Purpose To investigate the diagnostic performance of gantry-free CBCT versus two-dimensional radiography in adults and children with acute elbow trauma. Materials and Methods In a retrospective study, consecutive patients with elbow trauma and positioning difficulty in a gantry-based MDCT who underwent three-dimensional elbow imaging with a gantry-free CBCT after radiography were enrolled between January 2021 and April 2022 at a tertiary care university hospital. Imaging data sets were independently analyzed for fracture presence, articular involvement, and multi-fragment injuries by three radiologists. Diagnostic performance was calculated individually with surgical reports serving as the reference standard. Differences between radiography and CBCT were compared with the McNemar test. Diagnostic confidence was estimated subjectively by each reader, and results were compared with the Wilcoxon signed-rank test. Results Elbow examinations of 23 adults and children (mean age ± SD, 49 years ± 23; seven women) were included with individual assessment of humerus, radius, and ulna (69 bones; 36 fractured). Multi-fragmentary fracture patterns and involvement of articular surfaces were ascertained in 28 and 30 bones, respectively. CBCT allowed for similar or higher sensitivity compared with radiography in the assessment of fractures (range for three readers, 94%-100% vs 72%-81%; respectively, P ≤ .06-.008), articular surface involvement (90%-97% vs 73%-87%; P ≤ .25), and multi-fragmentary patterns (96%-96% vs 68%-75%; P ≤ .03). Readers' diagnostic confidence improved considerably with access to CBCT data sets versus radiographs (all P ≤ .001). For CBCT, the median dose-length product was 70.9 mGy · cm, and the volume CT dose index was 4.4 mGy. Conclusion In acute elbow injuries, gantry-free cone-beam CT enabled improved detection of fractures, articular involvement, and multi-fragmentary patterns compared with two-dimensional radiography. Published under a CC BY 4.0 license Online supplemental material is available for this article.

Surgical Fixation of Calcaneal Beak Fractures-Biomechanical Analysis of Different Osteosynthesis Techniques.

The calcaneal beak fracture is a rare avulsion fracture of the tuber calcanei characterized by a solid bony fragment at the Achilles tendon insertion. Treatment usually requires osteosynthesis. However, lack of biomechanical understanding of the ideal fixation technique persists. A beak fracture was simulated in synthetic bones and assigned to five different groups of fixation: A) 6.5-mm partial threaded cannulated screws, B) 4.0-mm partial threaded cannulated screws, C) 5.0-mm headless cannulated compression screws, D) 2.3-mm locking plate, and E) 2.8-mm locking plate. Different traction force levels were applied through an Achilles tendon surrogate in a material-testing machine on all stabilized synthetic bones. Outcome measures were peak-to-peak displacement, total displacement, plastic deformation, stiffness, visual-fracture-line displacement, and mode of implant failure. The 2.3- and 2.8-mm plating groups showed a high drop-out rate at 100 N tension force and failed under higher tension levels of 200 N. The fracture fixation using 4.0-mm partial threaded screws showed a significantly higher repair strength and was able to withhold cyclic loading up to 300 N. The lowest peak-to-peak displacement and the highest load-to-failure and stiffness were provided by fracture fixation using 6.5-mm partial threaded cannulated screws or 5.0-mm headless cannulated compression screws. As anticipated, large 6.5-mm screw diameters provide the best biomechanical fixation. Surprisingly, the 5.0-mm headless cannulated compression screws yield reliable stability despite the absent screw head and washer. When such large screws cannot be applied, 4.0-mm screws also allow reasonable fixation strength. Plate fixation should be implemented with precaution and in combination with a restrictive postoperative motion protocol. Finally, clinical cases about the surgical application and recovery are included.

Combining gantry-free cone-beam computed tomography with iterative metal artefact reduction for surgical follow-up imaging of the appendicular skeleton.

PURPOSE: Post-surgical evaluation of osteosynthesis material and adjacent tissue can be challenging in both radiography and cross-sectional imaging. This study investigates the performance of a multi-purpose X-ray scanner with cone-beam CT (CBCT) function and iterative metal artefact reduction capabilities in patients after osteoplasty of the appendicular skeleton. METHOD: Eighty individuals who underwent both conventional X-ray imaging and CBCT after osteoplasty of the hand/wrist (48), elbow (14), or ankle/foot (18) with the gantry-free twin robotic system were retrospectively enrolled. Radiological reports from clinical routine for both imaging modalities were retrospectively analyzed and compared with consensus expert reading by two musculoskeletal specialists serving as the standard of reference. Findings of screw dislocation or implant loosening, fragment displacement, and delayed healing were compared between X-ray and CBCT reports using the McNemar test. RESULTS: The median dose-area-product of CBCT and X-ray scans amounted to 27.98 and 0.2 dGy*cm2, respectively. Diagnostic accuracy for screw dislocation was superior in CBCT compared to standard radiograms (98.8 % vs 83.8 %; p = 0.002). Implant loosening (98.8 % vs 86.3 %; p = 0.006), fragment displacement (98.8 % vs 85.0 %; p < 0.001), and delayed healing (97.5 % vs 88.8 %; p = 0.016) were also more reliably detected in CBCT. Employing CBCT, postoperative complications were detected with a sensitivity and specificity of at least 95.8 % and 98.1 %, compared to 33.3 % and 92.86 % in radiography. CONCLUSIONS: With superior accuracy for various osteoplasty-related complications, the CBCT scan mode of a gantry-free twin robotic X-ray system with iterative metal artefact reduction aids post-surgical assessment in the appendicular skeleton.

Treatment of avascular necrosis of the humeral head - Postoperative results and a proposed modification of the classification.

BACKGROUND: Avascular necrosis of the humeral head after proximal humeral fracture i.e. type 1 fracture sequelae (FS) according to the Boileau classification is a rare, often painful condition and treatment still remains a challenge. This study evaluates the treatment of FS type 1 with anatomic and reverse shoulder arthroplasty and a new subclassification is proposed. METHODS: This single-center, retrospective, comparative study, included all consecutive patients with a proximal humeral FS type 1 treated surgically in a four-year period. All patients were classified according to the proposed 3 different subtypes. Constant score (CS), Quick DASH score, subjective shoulder value (SSV) as well as revision and complication rate were analyzed. In the preoperative radiographs the acromio-humeral interval (AHI) and greater tuberosity resorption were examined. RESULTS: Of 27 with a FS type 1, 17 patients (63%) with a mean age of 64 ± 11 years were available for follow-up at 24 ± 10 months. 7 patients were treated with anatomic and 10 with reverse shoulder arthroplasty. CS improved significantly from 16 ± 7 points to 61 ± 19 points (p < 0.0001). At final follow-up the mean Quick DASH Score was 21 ± 21 and the mean SSV was 73 ± 21 points. The mean preoperative AHI was 9 ± 3 mm, however, 8 cases presented an AHI < 7 mm. 4 cases had complete greater tuberosity resorption. The complication and revision rate was 19%; implant survival was 88%. CONCLUSION: By using the adequate surgical technique good clinical short-term results with a relatively low complication rate can be achieved in FS type 1. The Boileau classification should be extended for fracture sequelae type 1 and the general recommendation for treatment with hemiarthroplasty or total shoulder arthroplasty has to be relativized. Special attention should be paid to a decreased AHI and/or resorption of the greater tuberosity as indirect signs for dysfunction of the rotator cuff. To facilitate the choice of the adequate prosthetic treatment method the suggested subclassification system should be applied.

Interobserver reliability of scapula fracture classifications in intra- and extra-articular injury patterns.

BACKGROUND: Morphology and glenoid involvement determine the necessity of surgical management in scapula fractures. While being present in only a small share of patients with shoulder trauma, numerous classification systems have been in use over the years for categorization of scapula fractures. The purpose of this study was to evaluate the established AO/OTA classification in comparison to the classification system of Euler and Rüedi (ER) with regard to interobserver reliability and confidence in clinical practice. METHODS: Based on CT imaging, 149 patients with scapula fractures were retrospectively categorized by two trauma surgeons and two radiologists using the classification systems of ER and AO/OTA. To measure the interrater reliability, Fleiss kappa (κ) was calculated independently for both fracture classifications. Rater confidence was stated subjectively on a five-point scale and compared with Wilcoxon signed rank tests. Additionally, we computed the intraclass correlation coefficient (ICC) based on absolute agreement in a two-way random effects model to assess the diagnostic confidence agreement between observers. RESULTS: In scapula fractures involving the glenoid fossa, interrater reliability was substantial (κ = 0.722; 95% confidence interval [CI] 0.676-0.769) for the AO/OTA classification in contrast to moderate agreement (κ = 0.579; 95% CI 0.525-0.634) for the ER classification system. Diagnostic confidence for intra-articular fracture patterns was superior using the AO/OTA classification compared to ER (p < 0.001) with higher confidence agreement (ICC: 0.882 versus 0.831). For extra-articular fractures, ER (κ = 0.817; 95% CI 0.771-0.863) provided better interrater reliability compared to AO/OTA (κ = 0.734; 95% CI 0.692-0.776) with higher diagnostic confidence (p < 0.001) and superior agreement between confidence ratings (ICC: 0.881 versus 0.912). CONCLUSIONS: The AO/OTA classification is most suitable to categorize intra-articular scapula fractures with glenoid involvement, whereas the classification system of Euler and Rüedi appears to be superior in extra-articular injury patterns with fractures involving only the scapula body, spine, acromion and coracoid process.

GIRD syndrome in male handball and volleyball players: Is the decrease of total range of motion the turning point to pathology?

BACKGROUND: Adaptations in glenohumeral range of motion may affect overhead athletes and lead to shoulder pathologies. OBJECTIVE: The purpose of this study was to evaluate glenohumeral internal rotation deficit (GIRD) and postero-superior impingement among male handball and volleyball players and the relationship between these pathologies and training level (amateur vs. professional), position (attack vs. no attack), experience (> 5 years vs. < 5 years) and sports. METHODS: Sixty-seven handball players and 67 volleyball players with a mean age of 25 [± 5] years were included. The range of motion including external and internal rotation in 90∘ abduction of the dominant and non-dominant shoulder was measured of each examined athlete. Visual analogue scale, disabilities of the shoulder and hand score, constant score and subjective shoulder value were recorded. The athletes were examined for postero-superior impingement and abduction force was measured with an isokinetic dynamometer. RESULTS: Internal rotation was significantly lower and external rotation was significantly greater in the dominant arm for both sports. 72% presented with GIRD. GIRD was more prevalent in athletes active for > 5 years (odds ratio (OR) 3), in those training > 3 times per week (OR 1.4) and in handball players (OR 2.7). 24% presented with postero-superior impingement. Players active for > 5 years (OR 1.22), professionals (OR 1.14), volleyball players (OR 1.19), offensive players (OR 2.2) and athletes with GIRD > 10∘ (OR 1.5) showed a higher prevalence of postero-superior impingement. CONCLUSION: GIRD is a common phenomenon in handball and volleyball players. Offensive players are frequently suffering from postero-superior impingement. GIRD > 10∘ leads in nearly 75% of the athletes to a decrease of total range of motion and a high rate of postero-superior impingement. Thus, a decreased range of motion seems to be the turning point from adaptation to pathology. Therefore, regular controls of range of motion and countermeasures by means of stretching the posterior shoulder joint should be integrated in the training content.

Anterior deltoid muscle tension quantified with shear wave ultrasound elastography correlates with pain level after reverse shoulder arthroplasty.

INTRODUCTION: Reverse shoulder arthroplasty (RSA) leads to medialization and distalization of the centre of rotation of the shoulder joint resulting in lengthening of the deltoid muscle. Shear wave ultrasound elastography (SWE) is a reliable method for quantifying tissue stiffness. The purpose of this study was to analyse if deltoid muscle tension after RSA correlates with the patients' pain level. We hypothesized that higher deltoid muscle tension would be associated with increased pain. MATERIAL AND METHODS: Eighteen patients treated with RSA were included. Constant score (CS) and pain level on the visual analogue scale (VAS) were analysed and SWE was performed on both shoulders. All three regions of the deltoid muscle were examined in resting position and under standardized isometric loading. RESULTS: Average patient age was 76 (range 64-84) years and average follow-up was 15 months (range 4-48). The average CS was 66 points (range 35-89) and the average pain level on the VAS was 1.8 (range 0.5-4.7). SWE revealed statistically significant higher muscle tension in the anterior and middle deltoid muscle region in patients after RSA compared to the contralateral non-operated side. There was a statistically significant correlation between pain level and anterior deltoid muscle tension. CONCLUSION: SWE revealed increased tension in the anterior and middle portion of the deltoid muscle after RSA in a clinical setting. Increased tension of the anterior deltoid muscle portion significantly correlated with an increased pain level. SWE is a powerful, cost-effective, quick, dynamic, non-invasive, and radiation-free imaging technique to evaluate tissue elasticity in the shoulder with a wide range of applications. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Locked fracture dislocations of the proximal humerus: postoperative results and a proposed modification of the classification.

BACKGROUND: Locked dislocations of the glenohumeral joint are disabling and often painful conditions and the treatment is challenging. This study evaluates the functional outcome and the different prosthetic treatment options for chronic locked dislocations of the glenohumeral joint and a subclassification is proposed. METHODS: In this single-center retrospective case series, all patients with a chronic locked dislocation treated surgically during a four-year period were analyzed. Constant score (CS), Quick Disabilities of Shoulder and Hand Score (DASH), patient satisfaction (subjective shoulder value (SSV)), revision rate and glenoid notching were analyzed. RESULTS: 26 patients presented a chronic locked dislocation of the glenohumeral joint. 16 patients (62%) with a mean age of 75 [61-83] years were available for follow-up at 24 ± 18 months. CS improved significantly from 10 ± 6 points to 58 ± 21 points (p < 0.0001). At the final follow-up, the mean DASH was 27 ± 23 and the mean SSV was 58 ± 23 points. The complication rate was 19% and the revision rate was 6%; implant survival was 94%. Scapular notching occurred in 2 (13%) cases (all grade 1). CONCLUSION: With good preoperative planning and by using the adequate surgical technique, good clinical short-term results with a low revision rate can be achieved. The authors suggest extending the Boileau classification for fracture sequelae type 2 and recommend using a modified classification to facilitate the choice of treatment as the suggested classification system includes locked posterior and anterior dislocations with and without glenoid bone loss. LEVEL OF EVIDENCE: IV.

Proximal humeral fracture morphology in patients with advanced cuff tear arthropathy: an observational study in a surgically treated cohort.

BACKGROUND: In the presence of cuff tear arthropathy (CTA), joint kinematics is alternated and fracture configuration might be different. The purpose of this study was to identify fracture patterns in patients with advanced CTA to facilitate recognition and treatment. METHODS: Radiographs and computed tomography scans of all patients undergoing surgical treatment for a proximal humeral fracture (PHF) in our institution during a 5-year period were retrospectively analyzed. Fracture pattern according to the AO-OTA and Resch classification and the presence of CTA were evaluated. Glenoid configuration according to Walch, fatty atrophy of the supraspinatus muscle and the centrum-collum-diaphyseal (CCD) angle were analyzed. RESULTS: A total of 574 out of 713 patients were included. Twenty-three patients (4%) with a mean age of 82 ± 8 years showed advanced CTA with acetabularization of the acromion (≥ stage 3 according to Hamada/Fukuda). There were exclusively valgus fractures with a mean CCD angle of 158° ± 18°. Patients with CTA ≥ grade 3 had a nearly twofold greater risk (risk ratio: 1.8; confidence interval (CI): 95% 1.6-1.9; p < 0.0001) of sustaining a valgus fracture compared to patients without or with CTA < grade 3. The risk for a tuberosity fracture was nearly twofold greater in patients without or with mild CTA (risk ratio: 1.68; confidence interval (CI): 95% 1.17-2.40; p = 0.0046) compared to those with advanced CTA. CONCLUSION: In advanced CTA, a predominantly valgus fracture pattern can be observed. In addition, fractures of the greater tuberosity were significantly less frequent and were rarely displaced. Up to date, no classification system for PHF has been developed in the setting of CTA although it might indicate a different treatment, and therefore, recognition is crucial. However, when present, this changes the fracture pattern and ability to treat the fracture as the rotator cuff can no longer be utilized as a means of reducing the fragments.

Higher primary stability of tuberosity fixation in reverse fracture arthroplasty with 135° than with 155° humeral inclination.

BACKGROUND: Proximal humeral fractures in elderly patients are frequently treated with reverse total shoulder arthroplasty, and tuberosity healing improves clinical outcome and patient satisfaction. So far reverse prostheses with different humeral inclination (HI) angles have been used. However, it has not been investigated yet if the HI angle affects the primary stability of the tuberosity fixation in primary reverse total shoulder arthroplasty for proximal humeral fractures in a biomechanical setting. METHODS: A 4-part fracture was created in 7-paired human cadaver proximal humeri after preceding power analysis. After randomization in a pairwise fashion, reverse prostheses with either 135° (n = 7) or 155° (n = 7) were implanted. The tuberosities were reduced anatomically to the metaphysis of the prostheses and were fixed with 3 suture cerclages in a standardized technique. Tightening was performed with a cerclage tension device with 50 Newton meter (N m). Before biomechanical testing, the initial vertical and horizontal gap formation was measured. The humeri were placed in a custom-made test setup enabling internal and external rotation. Cyclic loading with a gradually increasing load magnitude was applied with a material testing machine starting with 20 N m and increasing by 5 N m after each 100th cycle until failure (>15° rotation of the tuberosities). Any motion of the tuberosities was measured with a 3-dimensional camera system. RESULTS: Overall, the 155° group reached an average of 1460 ± 270 cycles and the 135° group of 1900 ± 271 cycles (P = .048). In contrast to the 135° group, in the 155° group, a mean initial vertical (0.3 ± 0.7 mm) and horizontal (2.7 ± 3.3 mm) gap formation could be observed before cyclic loading. After 1100 cycles, the 155° group showed increased rotation of both lesser and greater tuberosities in all 3 axes around the humeral shaft compared with the 135° group. CONCLUSION: Primary stability of the reattached tuberosities is significantly increased, whereas rotational movements are decreased in prostheses with an anatomic HI of 135° compared with a 155° HI according to the original Grammont design. In addition, a 135° HI allows an exact anatomic reposition of the tuberosities, whereas this was not possible for the 155° design. However, transferability and clinical relevance of these biomechanical results have to be verified with clinical studies.

Tensioning device increases biomechanical stability of tuberosity fixation technique with cerclage sutures in reverse shoulder arthroplasty for fracture.

BACKGROUND: Complex proximal humeral fractures in elderly patients are increasingly treated with primary reverse total shoulder arthroplasty. Many surgeons use cerclage sutures for tuberosity fixation in reverse total shoulder arthroplasty for proximal humeral fractures. In this study, we hypothesized that sutures fixated with a tensioning device would achieve higher initial fixation stability of the tuberosities compared with manually knotted cerclage sutures in a biomechanical model. METHODS: A 4-part fracture was created in 7-paired human cadaver proximal humeri. The tuberosities were reduced anatomically and fixed with 3 cerclage sutures in a standardized technique. Tightening was performed either manually (n = 7) or with a cerclage tensioning device with 50 Newton meter (N m) (n = 7). The humeri were placed in a custom-made test setup enabling internal and external rotation. Cyclic loading with gradually increasing load was applied with a material testing machine starting with 20 N m and increasing by 5 N m after each 100th cycle until failure (>15° rotation of the tuberosities). Motion of the tuberosities was measured with a 3-dimensional camera system. RESULTS: Overall, the knot group reached 1040 ± 152 cycles, and the device group reached 1820 ± 719 cycles (P = .035). Major fragment motion was detected in the humeral shaft axis and in the distal divergence of the tuberosities. After 900 cycles, the knot group showed increased rotation of both lesser and greater tuberosities in all 3 axes around the humeral shaft compared with the device group. CONCLUSION: Biomechanical stability of the reattached tuberosities is significantly increased, and rotational movement of the tuberosities is decreased after tightening of the applied cerclage sutures with a tensioning device compared with manual knotting. However, transferability of these promising biomechanical results and their clinical relevance have to be verified with clinical studies.

Severe Heterotopic Ossification with Proximal Entrapment of the Ulnar Nerve following Primary Anterior Shoulder Dislocation.

Heterotopic ossifications (HO) in the shoulder are rare. The effectiveness of conservative treatment is limited, and therefore, symptomatic cases are usually treated surgically. However, there are no guidelines for the surgical treatment of HO. Herein, we report the case of a 45-year-old man with severe HO and proximal entrapment of the ulnar nerve following primary anterior shoulder dislocation without concomitant injuries (e.g., fracture and rotator cuff tears). Surgical intervention was indicated, including resection of HO and neurolysis of the brachial plexus. Nine months after surgery, the patient presented with restored shoulder function, pain relief, and good patient satisfaction. The case shows that the ulnar nerve can also be impaired due to HO following shoulder dislocation.

Proximal humeral fracture morphology in patients with advanced osteoarthritis: An observational study in a surgically treated cohort.

BACKGROUND: Several factors affect proximal humeral fracture (PHF) morphology. In the presence of glenohumeral osteoarthritis (GOA), the joint kinematics is alternated which might influence fracture configuration. The purpose of this study was to identify fracture patterns in patients with advanced osteoarthritis to facilitate recognition and treatment. METHODS: In this retrospective analysis, and computed tomography (CT) scans of all patients undergoing surgical treatment for a PHF during a 5-year period were analyzed. Fracture pattern according to the AO Foundation/Orthopaedic Trauma Association (AO-OTA) classification and the presence of GOA were evaluated. In addition, critical shoulder angle (CSA), glenoid configuration, and glenoid inclination (GI) were measured. RESULTS: Of the 713 patients, 574 met the inclusion criteria. A total of 166 patients showed radiological signs of GOA (28.9%). Advanced GOA (stage 2 or 3) was identified in 23 patients (4.0%). In this group, the mean age was 77 ± 10 years, mean CSA was 28.8 ± 4.2°, and the mean GI was 19.0 ± 7.8°. All fractures were extra-articular metaphyseal fractures (5 A2, 11 A3, 7 B1.1). Patients with advanced GOA had more than threefold risk (risk ratio 3.2; confidence interval 95% 2.80-3.74; p < 0.0001) for sustaining a metaphyseal fracture. In patients with GOA grade 1 compared to patients with no radiographic signs of GOA, this could not be observed. CONCLUSION: Patients experiencing PHF with radiological signs of advanced GOA have a higher risk of sustaining a metaphyseal fracture compared to individuals with the absence of or mild GOA. To date, no classification system for PHFs takes preexisting osteoarthritis into account, although it might indicate a different treatment and therefore the recognition is crucial.