Stemless components lead to improved radiographic restoration of humeral head anatomy compared with short-stemmed components in total shoulder arthroplasty.

BACKGROUND: Restoring the native center of rotation (COR) in total shoulder arthroplasty (TSA) has been shown to improve postsurgical function, subjective outcomes, and implant longevity. The primary purpose of this study was to compare postoperative radiographic restoration of the humeral COR between short-stem and stemless humeral implants by evaluating the mean COR shift between the 2 techniques. Secondary outcomes evaluated were comparisons of COR shift outliers, humeral head implant thickness and diameter, direction of COR shift, and neck-shaft angle (NSA). METHODS: This study was a multicenter retrospective comparative study using a consecutive series of primary anatomic TSA patients who received either a short-stem or stemless humeral implant. Radiographically, COR and NSA were measured by 2 fellowship-trained surgeons using the best-fit circle technique on immediate postoperative Grashey radiographs. RESULTS: A total of 229 patients formed the final cohort for analysis that included 89 short stems and 140 stemless components. The mean COR shift for short stems was 2.7 mm (±1.4 mm) compared with 2.1 mm (±0.9 mm) for stemless implants (P < .001). The percentage of short-stem implant patients with a >2 mm COR difference from native was 66.0% (n = 62) compared with 47.4% (n = 64) for stemless (P = .006). The percentage of short-stem patients with a >4 mm COR difference from native was 17.0% (n = 16) compared with 3.0% (n = 4) for stemless (P < .001). The mean humeral implant head thickness for short stems was 18.7 ± 2.2 mm compared with 17.2 ± 1.3 mm for stemless implants (P < .001). The mean humeral head diameter for short stems was 48.7 ± 4.4 mm compared with 45.5 ± 3.5 mm for stemless implants (P < .001). The NSA for the short-stem cohort was 136.7° (±3.6°) compared with 133.5° (±6.0°) for stemless (P < .001). CONCLUSIONS: Stemless prostheses placed during TSA achieved improved restoration of humeral head COR and were less likely to have significant COR outliers compared with short-stem implants.

Survival of stemless humeral head replacement in anatomic shoulder arthroplasty: a prospective study.

BACKGROUND: The long-term results of shoulder arthroplasty using stemless humeral head components with a mean follow-up period > 10 years were not available until now. The aim of this study was to evaluate the long-term results of shoulder arthroplasty using a stemless humeral head component. METHODS: Since 2005, we have documented stemless humeral head replacement prospectively. Seventy-five patients with a mean age of 57 years at surgery (40 hemi-shoulder arthroplasties [HSAs] and 35 total shoulder arthroplasties [TSAs], 38 women and 37 men) were clinically and radiologically followed up after a mean period of 126 months (range, 105-157 months). Functional results were documented using the age- and sex-normalized Constant-Murley score (CMS) (ie, relative CMS). RESULTS: The relative CMS improved significantly (P < .0001) from 56% preoperatively to 90% postoperatively. Its subcategories of pain (8 points preoperatively vs. 12 points postoperatively, P < .0001), activities of daily living (10 points vs. 15 points, P < .0001), range of motion (20 points vs. 29 points, P < .0001), and strength (7 points vs. 11 points, P = .011) improved significantly as well. There was no significant difference in preoperative CMS vs. postoperative CMS, as well as its subcategories, between HSA (44.8 points vs. 67.1 points, P < .0001) and TSA (44.4 points vs. 68.9 points, P = .004). Clinically and radiologically, we observed no loosening of the stemless humeral head component. Stress shielding around the humeral component was not detected. Upward migration of the humeral head was observed in 17.5% of patients (21.6% with HSA and 11.5% with TSA, P = .303). No implant failure was observed on the humeral side. At follow-up, 18.3% of patients had rotator cuff deficiency (13.9% with HSA and 25% with TSA, P = .280). Overall, 9.3% of stemless shoulder arthroplasties were revised to reverse TSAs (5% of HSAs and 14.3% of TSAs, P = .097). TSA showed a trend for a higher revision rate than HSA. Secondary glenoid wear occurred in 64.3% of HSAs, and none of the HSAs were converted to TSAs. We observed an incomplete radiolucent line < 2 mm in 30.4% and glenoid loosening in 11.4% of cemented glenoid components. Kaplan-Meier analysis revealed a 10-year survivorship rate of 96.5% and an estimated 13-year survivorship rate of 90.1% for stemless humeral components. CONCLUSION: Stemless humeral head replacement showed no loosening and a significant improvement in shoulder function after a mean period of 11 years. The long-term clinical and radiologic results as well as the survivorship of anatomic shoulder arthroplasty using a stemless humeral head implant are comparable to the long-term results of standard stemmed anatomic shoulder arthroplasty.

Prospective midterm results of a new convertible glenoid component in anatomic shoulder arthroplasty: a cohort study.

PURPOSE: The purpose of our study was to evaluate the clinical and radiological results of a new anatomic convertible cementless glenoid component. METHODS: Forty-eight patients with a mean age of 67.3 years were clinically and radiologically followed-up with a mean of 49 months. Indications for glenoid replacement were A2 glenoid wear in 21.7%, B1 glenoid wear in 28.3%, B2 glenoid wear in 28.3%, B3 glenoid wear in 13%, D glenoid wear in 2.2%, and glenoid component loosening in 6.5%. RESULTS: The Constant-Murley score improved significantly (p < 0.0001) from 50% pre-OP to 103% post-OP. Patients with a B3 glenoid type according to Walch achieved a significant (p = 0.044) lower Constant-Murley Sscore post-OP compared to patients with a B1 glenoid type (88% vs 106%). The mean subluxation index changed significantly (p < 0.0001) from 0.54 pre-OP to 0.46 post-OP. At the metal-back bone interface an incomplete radiolucent line < 1 mm was observed in two cases (4.2%) and an incomplete radiolucent line < 2 mm was observed in another two cases (4.2%). PE dissociation occurred in two cases. No glenoid loosening was observed. The implant related revision rate was 4.2% (2 cases). All components (n = 612.5%) requiring conversion to reverse were converted without any further complications or loosening. CONCLUSION: Good functional results can be achieved in cases with a B1 and a B2 glenoid after anatomic shoulder arthroplasty using the described metal back glenoid. A conversion from an anatomic to a reverse glenoid component were possible in all cases without any further complications. Conversion of the anatomic glenoid component to a reverse system alleviates revision surgery.

Reduction of CO2 Emission from Off-Gases of Steel Industry by Dry Reforming of Methane.

In a novel process, CO2 and CH4 from the off-gases of the coke oven and blast furnace are used in homogeneous reforming of those greenhouse gases to valuable syngas, a mixture of H2 and CO. Synthetic mixtures of the off-gases from those large apparatuses of steel industry are fed to a high-temperature, high-pressure flow reactor at varying temperature, pressure, residence time, and mixing ratio of coke oven gas (COG) to blast furnace gas (BFG). In this study, a maximal reduction of 78.5 % CO2 and a CH4 conversion of 95 % could be achieved at 1350 °C, 5.5 bar, and a COG/BFG ratio of 0.6. Significant carbonaceous deposits were formed but did not block the reactor tube in the operational time window allowing cyclic operation of the process. These measurements were based on prior thermodynamic analysis and kinetic predictions using an elementary-step reaction mechanism.

Short-term safety, function, and quality of life in patients treated with Univers Revers prosthesis: a multicenter 2-year follow-up case series.

BACKGROUND: The use of reverse total shoulder arthroplasty (RTSA) has dramatically increased in recent years with the advent of new prosthesis designs regularly entering the market. We define the rate of local complications during the first 2 years after RTSA with the Univers Revers prosthesis and describe the changes in radiologic outcomes, as well as function, pain, satisfaction, and quality of life. METHODS: This multicenter, prospective case series included rotator cuff tear arthropathy patients who underwent RTSA with the Univers Revers. Incidence percentages of complications and pathologic radiographic changes were documented. Mixed-model linear regression was used to examine changes in range of motion, shoulder function (Constant score, Shoulder Pain and Disability Index, Subjective Shoulder Value), and quality of life (EQ-5D-5L [European Quality of Life 5 Dimensions 5 Level] and EQ-VAS [EuroQol Visual Analog Scale]). RESULTS: Of 187 patients, 59.4% were women, and the mean age was 75.3 years (range, 56-91 years). Twenty-five percent of patients had a postoperative complication; 5 complications were severe (2.7%, 5 of 187), whereby 2 were implant related (1.1%; 95% confidence interval [CI], 0.1%-3.8%). The incidence of scapular notching was 10.6% (95% CI, 6.5%-16%). After 2 years, abduction, flexion, and abduction strength improved by 54° (95% CI, 50°-58°), 57° (95% CI, 53°-60°), and 5 kg (95% CI, 4-5 kg), respectively (P < .001), whereas external rotation at 0° (1°; 95% CI, -1° to 3°) did not improve (P = .4). The Constant score improved by 39 (95% CI, 38-41); Shoulder Pain and Disability Index, by 50 (95% CI, 47-52); and Subjective Shoulder Value, by 43 (95% CI, 41-45) (P < .001). Furthermore, the EQ-5D-5L index value improved by 0.31 (95% CI, 0.30-0.33), and the EQ-VAS score improved by 16 (95% CI, 14-18) (P < .001). CONCLUSION: Our case series showed a low complication rate with a consistent clinically relevant and statistically significant improvement across most clinical and patient-reported outcomes for the Univers Revers. Long-term safety requires further investigation.

Nine-year outcome after anatomic stemless shoulder prosthesis: clinical and radiologic results.

BACKGROUND: Several stemless shoulder implants are available on the market, but only a few studies have presented results with sufficient mid- to long-term follow-up. The present study evaluated clinical and radiologic outcomes 9 years after anatomic stemless shoulder replacement. METHODS: This is a prospective cohort study evaluating the stemless shoulder prosthesis since 2005. Anatomic stemless shoulder replacement using a single prosthesis was performed in 49 shoulders; 17 underwent total shoulder replacement, and 32 underwent hemiarthroplasty. Forty-three patients were clinically and radiologically monitored after a mean of 9 years (range, 90-127 months; follow-up rate, 88%). The indications for shoulder replacement were primary osteoarthritis in 7 shoulders, post-traumatic in 24, instability in 7, cuff tear arthropathy in 2, postinfectious arthritis in 1, and revision arthroplasty in 2. RESULTS: The Constant-Murley Score improved significantly from 52% to 79% (P < .0001). The active range of motion also increased significantly for flexion from 101° to 118° (P = .022), for abduction from 79° to 105° (P = .02), and for external rotation from 21° to 43° (P < .0001). Radiologic evaluation revealed incomplete radiolucency in 1 patient without clinical significance or further intervention. No revision caused by loosening or countersinking of the humeral implant was observed. CONCLUSIONS: The 9-year outcome after stemless shoulder replacement is comparable to that of third- and fourth-generation standard shoulder arthroplasty.

Is the stemless humeral head replacement clinically and radiographically a secure equivalent to standard stem humeral head replacement in the long-term follow-up? A prospective randomized trial.

BACKGROUND: Stemless humeral head replacement represents a young generation of shoulder arthroplasty. This study evaluated the differences of this new stemless design compared with the fourth-generation standard stemmed design. METHODS: Total shoulder arthroplasty was performed in 20 patients with a stemless shoulder prosthesis (group 1) and in 20 patients with a standard stem humeral head replacement (group 2). Twenty-nine patients were examined clinically and radiographically at a minimum follow-up of 2 years and a minimum follow-up of 5 years. Functional results were assessed using the age- and gender-related Constant Score (CS). The radiographic analysis used native x-rays in 3 planes. RESULTS: The postoperative CS improved significantly in both groups, with no significant difference between the minimum of 2-year and 5-year follow-up. The difference in the CS, its subcategories, and active range of motion between the implant groups was not significant. A significant difference was observed in the radiographic analysis for the zone adjacent to the humeral calcar, with a lower bone mineral density in 41% of group 2 and in 0% in group 1. Radiolucent lines were statistically more frequent in group 2. No statistical differences were observed between the implant groups for the change of the inclination angle, the medial offset, and the lateral offset. CONCLUSION: Both implants showed consistently good functional and radiologic results without a significant difference and achieved an anatomic reconstruction of the humeral head geometry in the coronal plane.

Glenoid deformity in the coronal plane correlates with humeral head changes in osteoarthritis: a radiographic analysis.

BACKGROUND: A variety of measurements can be used to assess radiographic osteoarthritic changes of the shoulder. This study aimed to analyze the correlation between the radiographic humeral-sided Samilson and Prieto classification system and 3 different radiographic classifications describing the changes of the glenoid in the coronal plane. METHODS: The study material included standardized radiographs of 50 patients with idiopathic osteoarthritis before anatomic shoulder replacement. On the basis of radiographic measurements, the cases were evaluated using the Samilson and Prieto grading system, angle ß, inclination type, and critical shoulder angle by 2 independent observers. RESULTS: Classification measurements showed an excellent agreement between observers. Our results showed that the humeral-sided Samilson and Prieto grading system had a statistically significant good correlation with angle ß (observer 1, r = 0.74; observer 2, r = 0.77; P < .05) and a statistically significant excellent correlation with the inclination type of the glenoid (observer 1, r = 0.86; observer 2, r = 0.8; P < .05). A poor correlation to the critical shoulder angle was observed (r = -0.14, r = 0.03; P > .05). CONCLUSIONS: The grade of humeral-sided osteoarthritis according to Samilson and Prieto correlates with the glenoid-sided osteoarthritic changes of the glenoid in the coronal plane described by the angle ß and by the inclination type of the glenoid. Higher glenoid-sided inclination is associated with higher grade of osteoarthritis in primary shoulder osteoarthritis.

Classification of humeral head pathomorphology in primary osteoarthritis: a radiographic and in vivo photographic analysis.

BACKGROUND: The purpose of this study was to characterize the pathologic changes of the osteoarthritic humeral head. METHODS: The study included 55 patients with primary osteoarthritis who underwent anatomic shoulder arthroplasty. Several radiologic parameters (radiography, magnetic resonance imaging) were assessed. Humeral head deformity in the transverse plane and humeral cartilage erosion in the coronal plane were chosen for photographic measurements from the resected humeral heads. RESULTS: In the coronal plane, 82% of patients presented with an aspherical humeral head shape with a significantly longer caudal osteophyte. In the transverse plane, 50% of all patients showed a decentered apex. Patients with an aspherical humeral head shape in the transverse plane showed an aspherical humeral head shape in the coronal plane in 94% and a significantly longer osteophyte than patients with spherical humeral head shape, showing a 3-dimensional deformity of the humeral head during progression of primary osteoarthritis. Patients with an osteophyte length between 7 and 12 mm were associated with a glenoid type B2 in 30% and a decentered apex in the transverse plane in 38%. Patients with a humeral osteophyte longer than 13 mm were significantly more frequently associated with a type B2 glenoid (71%; P < .0001) and a decentered apex in the transverse plane in 52%. CONCLUSION: It seems that the progression of primary osteoarthritis of the glenohumeral joint is characterized by an increasing 3-dimensional deformity of the humeral head related to the glenoid morphology. We therefore propose an extended Samilson-Prieto classification with type A (spherical) and type B (aspherical) and grade I-IV osteophytes.

[Chronic acromioclavicular joint injury of Rockwood V type with concomitant chronic anterior sternoclavicular instability]. / Chronische Acromioclaviculargelenkverletzung Typ Rockwood V mit gleichzeitiger chronischer anteriorer sternoclavicularer Instabilität.

Bipolar dislocation of the clavicle is rare. In the literature, every reported bipolar dislocation of the clavicle is caused by a traumatic injury with loss of function of the affected shoulder. Currently, there is no recommendation to treat. A conservative treatment can be tried first to achieve adequate shoulder function. If this cannot be achieved, surgical treatment will be indicated. In the literature, many options for surgical treatment are described. This article presents a case of a chronic Rockwood V injury with chronic anterior sternoclavicular joint instability. The special feature of this case was the arthroscopically assisted stabilization of the acromioclavicular joint (ACJ) with the ipsilateral semitendinosus tendon graft and the open stabilization of the sternoclavicular joint (SCJ) with the ipsilateral gracilis tendon graft. A lateral fracture of the clavicle in the course of the postoperative treatment was treated with a plate osteosynthesis. At follow-up after six months, the postoperative shoulder function was restored. The ACJ and the SCJ were stable in clinical and radiographic examination. This case report shows the first surgical treatment using two tendon grafts for combined stabilization of the ACJ and SCJ.

How to discriminate between acute traumatic and chronic degenerative rotator cuff lesions: an analysis of specific criteria on radiography and magnetic resonance imaging.

BACKGROUND: Discrimination between acute traumatic and chronic degenerative rotator cuff lesions (RCLs) is an important aid to decision making in therapeutic management. To date, no clinical signs or radiologic findings that enable confident differentiation between these distinct etiologic entities have been identified. The purpose of this investigation was to perform a systematic analysis of known radiographic and magnetic resonance imaging (MRI) features of RCLs and of further, not yet accurately described parameters. The hypothesis was that there are specific radiologic features that allow reliable discrimination between traumatic and nontraumatic RCLs. METHODS: Fifty consecutive patients with RCLs confirmed by MRI were enrolled in this study. Group A was made up of 25 patients with a history of trauma within the previous 6 weeks and no pre-existing shoulder pain, whereas group B comprised 25 patients with shoulder pain for not more than 12 months and no history of relevant trauma. Radiographs and magnetic resonance images were analyzed in a standardized protocol. RESULTS: No radiographic features were found to differ significantly between the 2 groups. On MRI, edema in the injured muscle was more common in group A (37.5% vs 4%, P = .04). A characteristic feature in traumatic RCLs was a wavelike appearance (kinking) of the central tendon (64% vs 32%, P = .03). In group B, more muscular atrophy was found (29.2% vs 60%, P = .02). Thinning and retraction did not differ between the groups. CONCLUSION: MRI, but not radiography, can be used to help discriminate between traumatic and nontraumatic RCLs. Although no absolute distinguishing feature was found, edema, kinking, and muscular atrophy are positive criteria for differentiation.

Midterm results of stemless shoulder arthroplasty: a prospective study.

BACKGROUND: This study evaluated the functional and radiologic results of shoulder arthroplasty using a single type of stemless humeral head implant with a minimum follow-up of 5 years. METHODS: Stemless shoulder arthroplasties in 78 patients at a mean age of 58 years were prospectively evaluated at a mean clinical and radiologic follow-up of 72 months. Functional results were documented using the age- and sex-adjusted Constant score with standardized radiographic examination. RESULTS: The Constant score improved significantly from 38.1% to 75.3% (P < .0001). Active range of motion improved significantly for flexion (from 114° to 141°), abduction (from 74° to 130°), and external rotation (from 25° to 44°; P < .0001). Bone mineral density was reduced in 34.9% of the older population, without an influence on shoulder function (Constant score without lowering of bone density; 73%; Constant score with lowering of bone density 80%; P = .404). The overall complication rate was 12.8%, with an overall revision rate of 9%. None of the stemless implants were revised for loosening. CONCLUSION: The functional and radiologic results of the stemless shoulder arthroplasty are comparable to the third and fourth generation of standard stem arthroplasty.

Results of arthroscopic partial repair of large retracted rotator cuff tears.

PURPOSE: To evaluate the midterm results of partial rotator cuff repair using the Constant score and the acromiohumeral radiographic measurement. METHODS: Thirty-eight patients with a mean age of 65 years and a large retracted rotator cuff tear (at least 2 tendons) were included in the study. Patients underwent clinical examination, standard radiography, and isometric strength testing at a mean follow-up of 47 months. The rotator cuff tears were classified as posterosuperior, anterosuperior, or global tears (≥3 tendons), and an arthroscopic partial repair was performed. RESULTS: The mean Constant score significantly increased from 56 points before surgery to 71 points after surgery (P = .041); the mean age- and sex-adjusted Constant score significantly improved from 63% to 90% at a mean follow-up of 47 months after arthroscopic partial rotator cuff repair (P = .003); and the subcategories pain and activity significantly improved (P = .001, P = .014, respectively). The active range of motion improved from 133° of flexion and 111° of abduction before surgery to 163° of forward flexion and 156° of abduction after surgery (P < .001). However, the active range of external rotation decreased from 44° before surgery to 36° after surgery. Further, there was a trend toward a decrease in the mean acromiohumeral distance from 7.0 mm before surgery to 5.6 mm after surgery. The abduction strength did not significantly improve after surgery (4.2 kg before surgery and 4.8 kg after surgery; P = .116). CONCLUSIONS: An arthroscopic partial repair of the rotator cuff is an effective tool to improve the Constant score by restoring active forward flexion and abduction and through pain relief. Further, we found that a pathologically decreased acromiohumeral distance cannot be reversed by a partial rotator cuff repair. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Midterm results of a total shoulder prosthesis fixed with a cementless glenoid component.

BACKGROUND: The aim of this study was to evaluate the midterm results and complications of a total shoulder arthroplasty implanted with a metal-backed, bone-ingrowth glenoid component. MATERIALS AND METHODS: In total, 62 patients (65 shoulders) diagnosed with primary osteoarthritis were treated with total shoulder arthroplasty with a cementless glenoid component. The mean age was 66 years (range, 54-85 years). Fifty-three patients were evaluated after a mean of 64 months (range, 26-85 months). Functional results were documented by use of the age- and sex-adjusted Constant score. Radiolucent line (RLL) assessment of the glenoid component was performed by use of true anteroposterior and axillary views. RESULTS: The Constant score improved significantly from 49% preoperatively to 89.8% postoperatively (P < .0001). Active range of motion improved significantly for flexion (from 118° to 146°), abduction (from 87° to 133°), and external rotation (from 21° to 44°) (P < .0001). In 3 cases (5.7%), RLLs of 1 mm or less were present, and 1 case (1.8%) had an RLL of 2 mm or less in 1 zone. Glenoid component loosening occurred in 5 cases (9.4%) because of breakage of the cage screw. Four of these patients presented preoperatively with a type B1 glenoid and one patient with type A2. Two of the patients who underwent revision also had a complete tear of the rotator cuff. The revision rate was 11.3% (6 patients) after a mean of 68 months. CONCLUSION: After midterm follow-up, clinical outcomes of patients operated on with a cementless, metal-backed glenoid implant improved significantly. However, an unacceptable rate of complications and revisions was found. Glenoid loosening predominantly occurred in patients with preoperative eccentric glenoid morphology and was also related to cranial migration of the proximal humerus during the follow-up period.

The acromial index is not predictive for failed rotator cuff repair.

BACKGROUND: The main objective of this study was to evaluate the association between the acromial index (AI) and the incidence of recurrent tears of the rotator cuff (RC) in a cohort of patients with full thickness tears who underwent arthroscopic primary repair. METHODS: A prognostic study of a prospective case series of 103 patients with full thickness RC tears was undertaken. The average age was 59.5 years (39-74) and follow-up was 30.81 months (12-72). True anterior-posterior X-rays were obtained during the pre-operative evaluation. Pre and post-operative magnetic resonance imaging (MRI) were recorded. RESULTS: Eighteen cases with recurrent tears (17.4%) were seen on post-operative MRI. The average AI for patients with recurrent tears was 0.711 ± 0.065 and for patients without recurrent tears 0.710 ± 0.064 (p < 0.05). A positive association between age and recurrent tears of the RC was noted (average ages: recurrent tears group 63 ± 5.9 years; group without recurrent tears 58.8 ± 7.5 years) (r = -0.216; p = 0.029). We did not find an association between size of the primary tear and recurrent tears (r = -0.075; p < 0.05) or between degrees of retraction of the primary and recurrent tears of the cuff (r = -0.073; p < 0.05). We observed that 38.9% of the recurrent tears cases presented with more than one tendon affected before the arthroscopy. At follow-up, none of these recurrent tears showed more than one tendon affected on MRI evaluation. CONCLUSION: In this study, we found that the AI radiological measurement is not a predictor for recurrent tears of the RC after primary arthroscopic repair.

Hydrogen Production and Carbon Capture by Gas-Phase Methane Pyrolysis: A Feasibility Study.

Using natural gas and sustainable biogas as feed, high-temperature pyrolysis represents a potential technology for large-scale hydrogen production and simultaneous carbon capture. Further utilization of solid carbon accruing during the process (i. e., in battery industry or for metallurgy) increases the process's economic chances. This study demonstrated the feasibility of gas-phase methane pyrolysis for hydrogen production and carbon capture in an electrically heated high-temperature reactor operated between 1200 and 1600 °C under industrially relevant conditions. While hydrogen addition controlled methane conversion and suppressed the formation of undesired byproducts, an increasing residence time decreased the amount of byproducts and benefited high hydrogen yields. A temperature of 1400 °C ensured almost full methane conversion, moderate byproduct formation, and high hydrogen yield. A reaction flow analysis of the gas-phase kinetics revealed acetylene, ethylene, and benzene as the main intermediate products and precursors of carbon formation.

Hydrogen Production and Carbon Capture by Gas-Phase Methane Pyrolysis: A Feasibility Study.

Invited for this month's cover is the research group of Olaf Deutschmann and the team of Patrick Lott at the Karlsruhe Institute of Technology. The Cover image shows how an electrically heated reactor converts methane from natural gas or biogas into gaseous hydrogen and elemental carbon by means of high-temperature pyrolysis. The transfer of this technology into industrial applications can be a valuable contribution towards a decarbonization of the chemical industry and the establishment of a hydrogen economy. The Research Article itself is available at 10.1002/cssc.202201720.

Do anatomic variants of the acromion shape in the frontal plane influence pain and function in calcifying tendinitis of the shoulder?

PURPOSE: To evaluate the relationship of a large acromion index and calcifying tendinitis of the supraspinatus tendon at the shoulder. MATERIALS AND METHODS: Between 2002 and 2008, 109 consecutive patients with isolated calcifying tendinitis of the supraspinatus tendon were prospectively analysed by clinical investigation and standardized radiographs. Deposit size and appearance were measured and classified according to Bosworth and Gartner. The acromion index (AI) was calculated based on measurements on true anteroposterior radiographs. Pain record on VAS scale, active and passive range of motion and the constant score (CS) were recorded. RESULTS: The mean age of the patients was 48.2 ± 8.0 (n = 46 male 48.6 ± 7.3; n = 63 female 47.9 ± 8.6; P > 0.05). Pain and function were not significantly correlated with deposit size or classification. The acromion index (mean 0.64 ± 0.08) was not significantly correlated with the affected or dominant side, gender, deposit size or classification or any functional parameter like pain and the CS or its subgroups. CONCLUSION: The theoretical concept of a high acromion index resulting in an increased resulting upward force against the subacromial space, which influences pain and function in calcifying tendinitis of the shoulder, was not supported.

Are there advantages of the combined latissimus-dorsi transfer according to L'Episcopo compared to the isolated latissimus-dorsi transfer according to Herzberg after a mean follow-up of 6 years? A matched-pair analysis.

HYPOTHESIS: The aim of the study was to evaluate differences of clinical results between the latissimus-dorsi transfer combined with teres-major transfer (G1) and the isolated latissimus-dorsi transfer (G2) for the treatment of massive irreparable postero-superior rotator cuff tears. METHODS: We performed the combined latissimus-dorsi/teres-major transfer in 17 patients at a mean age of 57 years. Furthermore, 17 patients at a mean age of 61 years were treated using the isolated latissimus-dorsi transfer. Both groups were followed-up clinically, radiologically, and with surface electromyography using the same study protocol. RESULTS: The Constant score (CS) improved significantly from 48.3 points pre-op to 69.5 points post-op after a follow-up of 58 months in G1. The active range of motion improved in G1 sig. for flexion (124° pre-op, 166.5° post-op) and for abduction (117° pre-op, 163° post-op). The CS improved significantly from 45.1 points pre-op to 74.2 points post-op after a follow-up of 51 months in G2. The flexion and abduction increased significantly from 133.3° pre-op to 176° post-op, resp. from 113.3° pre-op to 173° post-op. The comparison of both surgical techniques showed a significant better active flexion and abduction for G2. CONCLUSION: Both techniques achieved good functional results but the isolated latissimus-dorsi transfer produced a better active abduction and flexion, whereas the combined latissmus-dorsi/teres-major transfer achieved an increase in abduction strength. In contrast to the combined latissimus-dorsi/teres-major transfer, a progression of cuff tear arthropathy was not observed with the isolated latissimus-dorsi transfer.

Is there an association between SLAP lesions and biceps pulley lesions?

PURPOSE: The purpose of this study was to evaluate the prevalence of SLAP and biceps reflection pulley lesions. The hypothesis was that these lesions do not occur concomitantly and they have a different etiology. METHODS: We prospectively analyzed 3,395 shoulder arthroscopies that were independently performed by 2 surgeons between 2004 and 2008 regarding the prevalence of SLAP and biceps pulley lesions. Intraoperative findings were correlated with patient history and clinical examination. Exclusion criteria were type I SLAP lesions, full-thickness rotator cuff tears, and a history of shoulder dislocation. RESULTS: This study included 182 patients with SLAP lesions (prevalence, 5.4%; 138 men; mean age, 47 years) and 87 patients with pulley lesions (prevalence, 2.6%; 63 men; mean age, 49 years). Isolated SLAP lesions were present in 157 cases, and isolated pulley lesions in 62 cases. The concomitant presence of a SLAP lesion and pulley lesion was significantly rare (10%, P = .003). In 55 (35%; 42 men [76%]; mean age, 43 years) of the cases with isolated SLAP lesions and 40 (65%; 27 men [68%]; mean age, 49 years) with isolated pulley lesions, there was a significant association with history of trauma (P < .01). Most SLAP lesions (32 [58%], P = .174 [not significant]) and most pulley lesions (28 [70%], P < .01) resulted from falling on the outstretched arm with external arm rotation in SLAP lesions and internal rotation in pulley lesions (P > .05). CONCLUSIONS: The concomitant presence of biceps tendon-associated lesions in the form of SLAP and pulley lesions is significantly rare. A history of falling on the abducted and externally rotated arm was typical in patients with SLAP lesions, whereas a fall on the arm with internal rotation was often noted in patients with pulley lesions. LEVEL OF EVIDENCE: Level IV, therapeutic case series.