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.

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.

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.

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.

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.

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.

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.

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.

Chondral defects of the glenohumeral joint: Long-term outcome after microfracturing of the shoulder.

INTRODUCTION: An increasing number of young patients are diagnosed with chondral lesions. Minimally invasive surgical techniques are important in order to delay progression of the early stages of osteoarthritis and the need for total joint replacement. MATERIALS AND METHODS: Patients (n = 32) who had received microfracturing of the shoulder were retrospectively enrolled, of whom 5 had received shoulder replacements after a mean time of 47 months. Of these patients, 23 completed the Disabilities of the Arm, Shoulder and Hand (DASH) and Constant-Murley Scores in addition to an additional subjective questionnaire. Patients were then clinically examined and received x­ray analysis of the operated shoulder. Data from an additional 4 patients were acquired by telephone interview. RESULTS: Mean follow-up was 105 months. Of the included patients, 13/27 patients reported no pain, 12/27 patients moderate pain. Of these 12, 6/27 reported pain only at night and 3/27 only during rest. Concerning the outcome of surgery, 19/27 patients were "satisfied" or "very satisfied". There was a statistically significant increase in internal rotation, but no further differences in the range of motion pre- and postoperatively. Patients without any signs of osteoarthritis before surgery showed statistically significantly better outcomes. There was a statistically significant increase in radiological signs of osteoarthrosis in pre- versus postoperative patients. Patients with bipolar lesions showed statistically significantly poorer Subjective Shoulder Value (SSV) results. CONCLUSION: Even though microfracturing does not prevent radiographic progression, microfracture of the glenohumeral joint might be worth considering as part of a treatment regimen for younger patients who may not yet be treated with arthroplasty.

[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.

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.

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.

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.

Arthroscopic Stabilization of Chronic Acromioclavicular Joint Dislocations: Triple- Versus Single-Bundle Reconstruction.

BACKGROUND: Arthroscopically assisted single-bundle (SB) or double-bundle coracoclavicular (CC) ligament reconstruction using autologous tendon grafts has been reported to provide acromioclavicular (AC) joint (ACJ) stability in chronic instability cases. Recently, additional AC ligament reconstruction to provide triple-bundle (TB) stabilization has been introduced but lacks a comparison of clinical and radiological outcomes. HYPOTHESIS: Arthroscopically assisted anatomic TB CC and AC reconstruction yields superior clinical and radiological results when compared with nonanatomic SB CC reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Twenty-six patients (mean [±SD] age, 46.9 ± 12.8 years) suffering from chronic high-grade ACJ instability underwent ACJ stabilization using autologous hamstring grafts. Twelve patients underwent combined anatomic TB CC and AC reconstruction using a semitendinosus tendon with clavicular interference screw fixation (TB group), and 14 underwent isolated SB CC reconstruction using the AC GraftRope system with a gracilis tendon (SB group). After a minimum follow-up of 2 years (mean, 29.0 ± 7.4 months), patients were evaluated radiologically and clinically using the Constant, American Shoulder and Elbow Surgeons (ASES), Taft, and Acromioclavicular Joint Instability Score (ACJI) outcome measures. RESULTS: The mean Constant score increased significantly in both groups, from 71.6 preoperatively to 88.8 postoperatively in the TB group and from 67.8 to 82.6 in the SB group (P ≤ .009). No intergroup difference was found regarding the final Constant or ASES scores. Regarding the ACJ-specific scores, the final outcomes were significantly different: 10.9 (TB group) versus 9.0 (SB group) for the mean Taft score (P = .018) and 84.7 versus 58.4, respectively, for the mean ACJI score (P = .0001). No significant radiological difference was found regarding the mean CC distance (10.7 mm [TB group] vs 13.1 mm [SB group]). The TB group showed superior horizontal ACJ stability (P = .011), which was associated with a better clinical outcome according to the ACJI and Taft scores. In the SB group, the rate of ACJ instability recurrence was higher (21% vs 8% [TB group]). CONCLUSION: Combined arthroscopically assisted anatomic TB CC and AC ligament reconstruction using an autologous semitendinosus tendon graft provides superior clinical and radiological results compared with isolated nonanatomic SB CC ligament reconstruction using the AC GraftRope system. In particular, the TB technique can better restore horizontal ACJ stability, which is associated with superior ACJ-specific outcome scores.

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.

From radial head to radiocapitellar to total elbow replacement: A case report.

INTRODUCTION: Radiocapitellar arthroplasty represents a possible treatment option for isolated osteoarthritis of the radial column. We report the first case of early failure of this procedure. PRESENTATION OF CASE: We present the case of a 41-year old male who sustained a terrible triad injury to his right elbow and subsequently underwent radial head arthroplasty. Due to overstuffing of the radial head prosthesis, capitellar erosion occurred and radiocapitellar arthroplasty was thus performed. Only one year later, conversion of the radiocapitellar replacement to total elbow arthroplasty was required as a result of progressive ulnohumeral osteoarthritis. DISCUSSION: According to the currently limited clinical data, radiocapitellar arthroplasty provides satisfactory results. However, biomechanical analysis shows that available prostheses do not sufficiently reproduce the radiocapitellar anatomy. The design of the prosthesis might thus have contributed to the rapid progression of ulnohumeral erosion following radiocapitellar arthroplasty although the poor outcome may also be attributed to the trauma itself along with the inadequate initial treatment. CONCLUSIONS: The indication for radiocapitellar arthroplasty warrants careful consideration given the results of biomechanical analysis and the early failure due to progressive ulnohumeral erosion seen in the present case.

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.

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.

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.