Do the humeral radiographic changes at 5-year follow-up affect the clinical outcomes of press-fit humeral stems in primary reverse shoulder arthroplasties?

INTRODUCTION: The purposes of this study were to analyze and compare the functional outcomes and radiological changes around the press-fit humeral components in two contemporary medialized reverse total shoulder arthroplasty (RTSA) systems at a minimum of 5-year follow-up. MATERIALS AND METHODS: Between December 2003 and December 2015, 249 consecutive RTSAs were performed at our hospital. Of these, 68 primary uncemented RTSA met our inclusion criteria. The Constant-Murley score (CMS), the modified Constant score, a visual analog scale (VAS) and active shoulder range of motion (ROM) were measured pre- and postoperatively. Radiological assessment was performed by plain radiographs at a minimum of 5 years postoperatively. RESULTS: At a mean follow-up of 80.2 months, there was no significant difference (p = .59) between the postoperative functional scores and range of motion of the two groups (Delta Xtend and Lima SMR). Radiological data of stress-shielding were observed in 38 patients (55.9%) being slightly more frequent in the Lima SMR group (21 patients) than in the Delta Xtend group (17 patients) (p = .62). CONCLUSIONS: Our study shows that the good functional results are similar between the two uncemented RTSA systems used and that they do not depend on the presence of radiological changes (stress-shielding) in the humeral stem at a minimum 5-year follow-up.

Neuropathy of the suprascapular and axillary nerves in rotator cuff arthropathy: a prospective electrodiagnostic study.

PURPOSE: Prevalence of axillary (AN) and/or suprascapular (SSN) neuropathy in rotator cuff tear arthropathy (RCTA) is unknown. We aimed to prospectively evaluate for preoperative neurodiagnostic abnormalities in order to determine their prevalence, location, and influence on reverse shoulder arthroplasty (RSA) outcomes. METHODS: Patients who underwent RSA for RCTA were prospectively included. An electromyography and nerve conduction study were performed pre and post-surgery. Clinical situation: VAS, Relative Constant-Murley Score (rCMS) and ROM over a minimum of two years follow-up. RESULTS: Forty patients met the inclusion criteria; mean follow-up was 28.4 months (SD 4.4). Injuries in RCTA were present in 83.9% (77.4% in AN and 45.2% in SSN). There were no differences on preoperative VAS, ROM, and rCMS between patients with and without preoperative nerve injuries. Four acute postoperative neurological injuries were registered under chronic preoperative injuries. Six months after RSA, 69% of preoperative neuropathies had improved (82.14% chronic injuries and 77.7% disuse injuries). No differences in improvement between disuse and chronic injuries were found, but patients with preoperative neuropathy that had not improved at the postoperative electromyographic study at six months, scored worse on the VAS (1.44 vs 2.66; p .14) and rCMS (91.6 vs 89.04; p .27). CONCLUSIONS: The frequency of axillary and suprascapular neuropathies in RCTA is much higher than expected. Most of these injuries improve after surgery, with almost complete neurophysiological recovery and little functional impact on RSA. However, those patients with preoperative neuropathies and absence of neurophysiological improvement six months after surgery have lower functional results.

Functional results of Circumferential Capsular Release in adhesive shoulder capsulitis. Comparative study of patients over and under fifty years of age.

INTRODUCTION: The aim of our study is to evaluate the functional and mobility outcomes in patients who have undergone arthroscopic circumferential arthrolysis of the shoulder and to find out if there are differences in the results in relation to the patient's age. MATERIALS AND METHODS: This is a retrospective case series of patients with idiopathic adhesive capsulitis treated by arthroscopic 360º circumferential capsulotomy in lateral position and followed for a minimum of 2 years. Range of motion (ROM), functional outcomes using the Constant Score (CS), health-related quality of life outcomes with the EuroQol Five Dimensions tool (EQ-5D), pain using the Visual Analogue Scale (VAS). RESULTS: A total of 26 shoulders were included, 10 men (41.7%) and 14 women (58.3%), with 2 patients being bilateral. The mean age was 48.64 ± 7.5 years, and the mean follow-up was 50.2 months. Postoperative ROM improved significantly compared to preoperative ROM (p < 0.05). Shoulder forward flexion improved by 38.6° (95%CI 22.3-54.9, p < 0.01), abduction by 35.2° (95%CI 17.6-52.8, p < 0.01) and external rotation by 21.9° (95%CI 12.8-30.9, p < 0.01 p < 0.01). Median internal rotation improved from buttock to T12 (p < 0.01). The mean improvement in CS was 54.3 ± 24.4 points (p < 0.01). The EQ-5D and VAS scores at the end of follow-up were 0.73 ± 0.23 and 2.73 ± 2.55, respectively. There were no statistical differences between young patients and patients aged 50 years or older in ROM or functional results. CONCLUSIONS: Patient age did not affect outcomes significantly, with patients older than 50 years showing similar results to younger patients.

From Solution to Surface: Persistence of the Diradical Character of a Diindenoanthracene Derivative on a Metallic Substrate.

Organic diradicals are envisioned as elementary building blocks for designing a new generation of spintronic devices and have been used in constructing prototypical field effect transistors and nonlinear optical devices. Open-shell systems, however, are also reactive, thus requiring design strategies to "protect" their radical character from the environment, especially when they are embedded in solid-state devices. Here, we report the persistence on a metallic surface of the diradical character of a diindeno[b,i]anthracene (DIAn) core protected by bulky end-groups. Our scanning tunneling spectroscopy measurements on single-molecules detected singlet-triplet excitations that were absent for DIAn species packed in assembled structures. Density functional theory simulations unravel that the molecular geometry on the metal substrate can crucially modify the value of the singlet-triplet gap via the delocalization of the radical sites. The persistence of the diradical character over metallic substrates is a promising finding for integrating radical-based materials into functional devices.

Suprascapular nerve injury after reverse total shoulder arthroplasty: correlation with screw out of vault penetration and functional situation: prospective study.

BACKGROUND: Baseplate screws have been suggested as a possible cause of suprascapular neuropathy after reverse total shoulder arthroplasty. This study aims to investigate the association between screw penetration out of the vault, electromyographic study, and the clinical outcomes. METHODS: A total of 31 patients who underwent reverse total shoulder arthroplasty for cuff tear arthropathy were prospectively enrolled. They were followed up for a minimum of 24 months. All patients underwent computed tomography 6 months postoperatively to determine the extraosseous position of the screws (perforation of the second bone cortex and protrusion into the supra- or infraspinatus fossa). Electrodiagnostic evaluation was performed preoperatively and postoperatively to stablish any relation between cortex perforation of the screw and suprascapular nerve (SSN) injury. Clinical outcomes pre- and postoperatively (Constant score, ranges of motion, and visual analog scale) of patients with and without documented injury were recorded. RESULTS: A total of 14 patients (45.2%) had an abnormal preoperative SSN electrodiagnostic study (chronic or disuse injuries), and 6 patients (19.4%) had an abnormal postoperative study (acute injury). Of the 6 patients, 2 cases appeared over the pre-existing lesion and 4 appeared over an intact preoperative nerve, all of them affecting the infraspinatus branch of the SSN. Perforation of the second cortex was detected for 60% of superior screws and 40% of posterior screws. The mean lengths of the superior and posterior screws were 30 and 18.2 mm, respectively. Patients with screw perforation of the second cortex were assessed as having a high risk of nerve injury (40% vs. 9.5%). CONCLUSIONS: Preoperative SSN injuries do not have a significant clinical impact and do not predispose to an acute postoperative SSN lesion. The Constant score and visual analog scale score for patients with acute SSN injuries were not statistically different from those without SSN injury. The extraosseous position of the screw increases the probability of an SSN injury to 31%. This risk is higher with the posterior screw, which leads us to question whether it is really necessary to use it.

Shoulder problems after percutaneous antegrade intramedullary nailing in humeral diaphyseal fractures using contemporary straight third-generation nail.

BACKGROUND: Antegrade intramedullary nailing in humeral shaft fracture has been abandoned by certain orthopedic surgeons because of rotator cuff injury caused by first- and second-generation intramedullary nails (IMNs). However, only a few studies have specifically addressed the results of antegrade nailing for the treatment of humeral shaft fractures with a straight third-generation IMN; thus, complications need to be re-evaluated. We hypothesized that fixation of displaced humeral shaft fractures with a straight third-generation antegrade IMN with the percutaneous technique avoid shoulder problems (stiffness and pain) incurred by first- and second-generation IMNs. METHODS: This was a retrospective, single-center, nonrandomized study of 110 patients with a displaced humeral shaft fracture between 2012 and 2019 treated surgically with a long third-generation straight IMN. Mean follow-up was 35.6 months (range, 15-44 months). RESULTS: There were 73 women and 37 men with a mean age of 64.7 ± 19 years. All fractures were closed (37.3% 12A1, 13.6% 12B2, and 13.6% 12B3 AO/OTA classification). Mean Constant score was 82 ± 19, Mayo Elbow Performance Score 96 ± 11 and the mean EQ-5D visual analog scale score was 69.7 ± 21.5. Mean forward elevation 150° ± 40°, abduction 148° ± 45°, and external rotation 38° ± 15°. Symptoms associated with rotator cuff disease were present in 6.4%. Evidence of radiographic fracture healing was detected in all but 1 case. One postoperative nerve injury and 1 adhesive capsulitis were present. Overall, 6.3% underwent second surgeries (4.5% were minor surgeries like hardware removal). CONCLUSION: Percutaneous antegrade intramedullary nailing of humeral shaft fractures with a straight third-generation nail considerably reduced complications related to shoulder problems and achieved good functional results.

The Spanish version of the Constant-Murley Shoulder Score: translation, cultural adaptation, and validity.

BACKGROUND: The Constant-Murley Score (CMS) is one of the most employed tools for assessing shoulder function. It was first devised in 1987 for the English population and is now widely used internationally. However, it had yet to be cross-culturally adapted and validated to Spanish, which is the world's second-most native language. Formal adaptation and validation of clinical scores is paramount for them to be used with rigorous scientific methodology. METHODS: Following international recommendations for the cross-cultural adaptation of self-report measures, the CMS was first adapted into Spanish in six stages: translation, synthesis, back-translation, a review by expert committee, pretesting, and final appraisal by expert committee. After conducting a pretest with 30 individuals, the Spanish version of the CMS was tested on 104 patients with various shoulder pathologies to assess content, construct, criterion validity, and reliability. RESULTS: No major conflicts were encountered in the process of cross-cultural adaptation, with 96.7% of pretested patients having a full understanding of every item in the test. The validation showed excellent content validity (content validity index = .90), construct validity (strong correlation between items within the same subsection of the test), and criterion validity (CMS - Simple Shoulder Test, Pearson r = .587, P = .01; CMS - American Shoulder and Elbow Surgeons, Pearson r = .690, P = .01). Reliability of the test was also excellent, with high internal consistency (Cronbach's α = .819), interrater reliability (intraclass correlation coefficient = .982), and intrarater reliability (intraclass correlation coefficient = .937), without showing ceiling or floor effects. CONCLUSION: Spanish version of the CMS has been proved to accurately reproduce the original score and to be easily comprehensible by native Spanish speakers with acceptable intrarater-interrater reliability and construct validity. INTRODUCCIóN: La escala de Constant-Murley (CMS) es una de las más empleadas para evaluar la función del hombro. Se ideó por primera vez para la población inglesa en 1987 y actualmente es ampliamente empleada a nivel internacional. Sin embargo, su validación y adaptación transcultural no se han realizado al español, la segunda lengua nativa más hablada en el mundo. Actualmente no puede resultar admisible el empleo de escalas en las que no tengamos la seguridad de que existe una equivalencia conceptual, cultural y lingüística entre la versión original y la empleada. MATERIAL Y MéTODO: La versión traducida al español de la CMS se realizó siguiendo las recomendaciones internacionales: traducción, síntesis de la traducción, retrotraducción, revisión por comité de expertos, pretest y validación. Tras la realización del pretest en 30 individuos, la versión española de la escala de CMS se probó en 104 pacientes con diferentes patologías de hombro para evaluar las propiedades psicométricas de la escala: contenido, constructo, validez de criterio y fiabilidad. RESULTADOS: No se encontraron problemas importantes durante el proceso de adaptación transultural con un entendimiento completo de todos los ítems del pretest por el 96.7% de los pacientes. La escala adaptada demostró una excelente validez de contenido (índice de validez de contenido = .90), de constructo (fuerte correlación entre ítems de la misma subsección del test), y de criterio (CMS-SST Pearson's r = .587, p = .01; CMS-ASES Pearson's r = .690, p = .01). La Fiabilidad del test resultó excelente, con una elevada consistencia interna (Cronbach's α = .819), fiabilidad interobservador (ICC = .982) e intraobservador (ICC = .937), sin efectos techo y suelo. CONCLUSIóN: La versión Española de la CMS garantiza la equivalencia con respecto al cuestionario original. Los presentes resultados, sugieren que esta versión es válida, fiable y reproducible para la evaluación de la patología de hombro en nuestro entorno.

Does fluoroscopy improve baseplate position compared to conventional technique in reverse shoulder arthroplasty? A preliminary study.

Background: Accurate placement of glenoid component in reverse shoulder arthroplasty remains a challenge for surgeons of all levels of expertise; however, no studies have evaluated the utility of fluoroscopy as a surgical assistance method. Methods: Prospective comparative study of 33 patients undergoing primary reverse shoulder arthroplasty during a 12-month period. Fifteen patients had a baseplate placed using the conventional "free hand" technique (control group), and 18 patients using intraoperative fluoroscopy assistance group, in a case-control design. Postoperative glenoid position was evaluated on postoperative Computed Tomography (CT) scan. Results: The mean deviation of version and inclination for fluoroscopy assistance vs. control group was 1.75° (0.675-3.125) vs. 4.2° (1.975-10.45) (p = .015), and 3.85° (0-7.225) vs. 10.35° (4.35-18.75) (p = .009). The distance from the central peg midpoint to the inferior glenoid rim (fluoroscopy assistance 14.61 mm/control 4.75 mm, p = .581) and the surgical time (fluoroscopy assistance 1.93 ± 0.57/control 2.18 ± 0.44 h, p = .400) showed no differences, with an average radiation dose of 0.45 mGy and fluoroscopy time of 14 s. Conclusions: Accurate axial and coronal scapular plane positioning of glenoid component is improved with intraoperative fluoroscopy at the cost of a greater radiation dose and without differences in surgical time. Comparative studies are needed to determine whether their use in relation to more expensive surgical assistance systems result in similar effectiveness.L evel of evidence : Level III, therapeutic study.

Poor Results After Arthroscopic Treatment of Irreparable Rotator Cuff Tears Using a Subacromial Balloon Spacer.

INTRODUCTION: Arthroscopic balloon spacer arthroplasty (BSA) is a relatively recent procedure for patients with irreparable rotator cuff tears, conceived to prevent degenerative joint changes and relieve subacromial pain. METHODS: This is a retrospective case series of 16 consecutive patients treated with BSA and followed up for a minimum 12 months. Besides BSA, partial tendon repair was done whenever possible. Radiographical parameters such as acromiohumeral distance and Hamada stage were measured preoperatively and postoperatively. Range of motion, functional results (Constant score; Simple Shoulder Test; American Shoulder and Elbow Surgeons score; and Disabilities of the Arm, Shoulder, and Hand score), health-related quality of life results with the EuroQol Five Dimensions tool, complications, and patient satisfaction were also analyzed. RESULTS: The mean age was 64 ± 10.3 years, and the male/female ratio was 6/10. Partial repair was achieved in five patients (31.2%) and did not influence functional or health-related quality of life results ( P = 0.11). The mean acromiohumeral distance and Hamada stage worsened from preoperative measures (3.7 ± 2.0 mm and 2.3 ± 1.1) to final follow-up measures (3.1 ± 2.4 mm and 3.1 ± 1.3). Shoulder abduction increased by 7.8° ± 26.8° and forward flexion decreased by 25.5° ± 32.4° after surgery. The functional results at the final follow-up were Constant 49.5 ± 18.0; American Shoulder and Elbow Surgeons 60.2 ± 27.2; Simple Shoulder Test 8.5 ± 4.6; and Disabilities of the Arm, Shoulder, and Hand 32.7 ± 12.1. The mean index value for the EuroQol Five Dimensions was 0.79, and perceived quality of life was 85.6 ± 15.4 of 100 points. 62.5% of the patients (10) were satisfied with surgery. The complication rate was 13% (2), accounting for one deep infection and one balloon migration. CONCLUSION: Theoretical benefits of BSA for delaying superior humeral head translation and arthropathic changes could not be demonstrated in our series. Its functional results and satisfaction rates are low, but self-reported quality of life after surgery does not seem impaired. Complications do not occur frequently but require reintervention and endanger joint viability. LEVEL OF EVIDENCE: Level IV (case series).

On-surface synthesis of Mn-phthalocyanines with optically active ligands.

The synthesis of novel organic prototypes combining different functionalities is key to achieve operational elements for applications in organic electronics. Here we set the stage towards individually addressable magneto-optical transducers by the on-surface synthesis of optically active manganese-phthalocyanine derivatives (MnPc) obtained directly on a metallic substrate. We created these 2D nanostructures under ultra-high vacuum conditions with atomic precision starting from a simple phthalonitrile precursor with reversible photo-induced reactivity in solution. These precursors maintain their integrity after powder sublimation and coordinate with the Mn ions into tetrameric complexes and then transform into MnPcs on Ag(111) after a cyclotetramerization reaction. Using scanning tunnelling microscopy and spectroscopy together with DFT calculations, we identify the isomeric configuration of two bi-stable structures and show that it is possible to switch them reversibly by mechanical manipulation. Moreover, the robust magnetic moment brought by the central Mn ion provides a feasible pathway towards magneto-optical transducer fabrication. This work should trigger further research confirming such magneto-optical effects in MnPcs both on surfaces and in liquid environments.

Reverse shoulder arthroplasty for proximal humeral fracture in the elderly. Cemented or uncemented stem?

OBJECTIVE: The purposes of this study were to compare functional outcomes, radiographic stem changes and complication rate in patients with proximal humeral fractures operated with cemented or uncemented RSA. METHODS: Retrospective review of 68 primary RSAs in PHF, 45 cemented/23 uncemented. Functional outcomes were evaluated according to constant, ASES scales and the range of motion (ROM). Radiographic assessment was performed at a minimum of two years post-operatively. RESULTS: The mean follow-up cemented/uncemented was 37.8/26.5 months (p = .04) and the mean age 78/80 years old (p = .09). The functional outcome and range of movement were equivalent in the two groups except for the forward flexion that was significantly higher in the cemented group (p = .03). Stress shielding was seen in 30.4% of uncemented group and none in the cemented. Anatomic tuberosity healing was significantly higher with uncemented components compared with cemented components (64% vs 91%, p = .02). Cemented stems had radiolucent lines with a width of 2 mm or more in three or more Gruen zones in 9% vs 0% in the uncemented group and an evident change in the stem position was present in 4% vs 0% in the non-cemented group. CONCLUSION: At mid-term follow-up, no differences in functional outcomes were detected depending on the stem fixation technique. Cemented stems, however, have a complication rate (including stem loosening) significantly higher than press-fit stems.

Third-generation intramedullary nailing for displaced proximal humeral fractures in the elderly: quality of life, clinical results, and complications.

INTRODUCTION: Antegrade insertion of third-generation intramedullary nail (IMN) has been shown to provide excellent results in young patients for treatment of displaced two-part surgical neck fracture. In elderly patients, osteoporosis makes internal fixation problematic and frequently contributes to failed fixation and poor clinical results. The purpose of this study was to report the health-related quality of life (HRQoL), functional results, and postoperative complications obtained with straight third-generation antegrade nailing of proximal humerus fractures (PHFs) in elderly patients. METHODS: A retrospective review of 32 patients aged 80 y.o. or older presenting a two-part or three-part PHFs treated with a straight IMN with a minimum follow-up of 12 months. Results assessed included 1) radiographic measures 2) clinical data: Charlson Comorbidity Index (CCI), VAS, range of motion (ROM), Individual Relative Constant score (IRC), Simple Shoulder Test (SST) and 3) Health-related Quality of life (HRQoL) with the EQ-5D index/EQ-VAS. RESULTS: Mean age was 82.1 (range 80-90) and mean follow-up was 45.6 months (range 16-53 months) with 91% of female patients and a mean CCI 4.6. 81% were two-part surgical neck fractures and 19% were three-part greater tuberosity fractures. The mean neck-shaft angle (NSA) at final follow-up was 132º ± 17.9º. 15.6% underwent hardware removal because of subacromial impingement and one patient (3%) was revised to RSA because of severe secondary fracture displacement. Mean IRC was 67,7 ± 30, the mean SST and VAS-Pain were 8.1 ± 3.1 and 3.2 ± 3.2, respectively, and the mean EQ-5D/EQ-VAS were 0.40 ± 0.33/64.2 ± 8.9. At last review, mean active forward flexion, abduction, and external rotation were 115º ± 35º, 100º ± 35º, and 20º ± 15º, respectively. CONCLUSION: Appropriate selection of fracture and proper operative technique with a third-generation nail result in good functional results and good HRQol with a low complication rate in elderly population.

Complications after open Latarjet procedure: influence of arm positioning on musculocutaneous and axillary nerve function.

BACKGROUND: Alterations in the anatomical relationships of the musculocutaneous (MCN) and axillary nerves and the influence of arm positioning on these relationships after a Latarjet procedure have been demonstrated in the cadaver, but there are no studies in the literature that establish if there is any neurophysiological repercussion. METHODS: We retrospectively identified 24 patients with a primary or revision open Latarjet procedure. A prospective clinical (Constant-Murley, Rowe and Walch-Duplay and active range of motion), radiographic (with CT), and electrodiagnostic evaluation was made at the most recent follow-up. RESULTS: Nonunion occurred in four patients (22%); there were, as well, one case of partial coracoid reabsorption (5%) and two (11%) with mild glenohumeral osteoarthritis. In the anatomical position, we found no alterations in the musculocutaneous nerve and two cases (11%) in the axillary nerve slight motor unit loss. In the risk position, 11 cases (61%) had neurophysiological involvement (36% had neurophysiological changes in the musculocutaneous nerve and 64% in the axillary nerve). No differences between patients with or without neurophysiologic changes were found: Constant 87/83; Rowe 89/90; Walch-Duplay 84/78; Forward elevation 175º/170º, abduction 165°/175°; external rotation 48°/45°. CONCLUSION: The rate of clinical electromyographic changes in the axillary and MCN in the abducted and externally rotated arm position (risk dislocation position) is higher than in neutral position. Nonunion of the coracoid process must play a role in these neurophysiological changes. Although in the medium-term they don't have clinical impact, further randomized prospective studies with a larger sample size are necessary to determine their true repercussion. LEVEL OF EVIDENCE: Level IV.

Dislocation after reverse total shoulder arthroplasty using contemporary medialized modular systems. Can we still consider it such a frequent complication?

INTRODUCTION: Improvement in reverse total shoulder arthroplasty (RTSA) prosthesis and technique has reduced the initially high complication and revision rates associated with this implant. However, instability continues to be a leading cause of reoperation after RTSA, being related in previous studies with medialized designs. The aim of this study was to determine the dislocation rate with the employment of two medialized modular systems of RTSA in our institution. MATERIALS AND METHODS: A retrospective review of two different modular systems of RTSA (SMR Modular Shoulder System and Delta XTEND Reverse Shoulder) was performed between 2009 and 2017 with a minimum 3-year follow-up. Baseline demographic, clinical (Constant, ASES and ROM), and radiographic data were collected. Characteristics of postoperative instability cases were also evaluated. RESULTS: 237 primary RTSA (41% SMR/59% Delta) and 34 revision RTSA (44% SMR/56% Delta) with a mean follow-up of 75.6 ± 5.2 months (79.2 SMR/86.3 Delta, p = .586) were included in the present study. Indications for primary RTSA were osteoarthritis, rotator cuff tear arthropathy and massive irreparable rotator cuff tear (64%), acute fracture (32%), and fracture sequelae (4%). Subscapularis tendon was always repaired in degenerative pathology and tuberosities reattached in traumatic cases. The mean age of the global series was 76.5 ± 5.3 years (75.8 SMR/78.6 Delta, p = .104) with a mean Constant/ASES score at final follow-up of 68.5 ± 4.3/72.9 ± 20.3 (71/68 SMR and 69/74 Delta, p = .653 and .642). Only 2 patients (one acute fracture and one fracture sequelae) suffered an early postoperative anterior dislocation (before 3 months) which represents a rate of .84% in primary cases and .73% including revision surgery. Closed reduction manoeuvres were not successful, and both patients required revision surgery. At the end follow-up, both were stable and had no further dislocations. CONCLUSION: The dislocation rate after RTSA with the employment of two contemporary modular systems with a medialized centre of rotation is extremely low, especially when compared with the previously published series with the original Grammont design. Acute fracture and fracture sequelae were the main diagnoses associated with this instability. The reasons for the low dislocation rate are multifactorial, but the improvement in the baseplate position according to the more recent standards of "ideal position" and technical aspects such as subscapularis repair or tuberosity reattachment in fractures probably play an important role in this aspect.

Complex fractures of the distal humerus in the elderly: primary total elbow arthroplasty or open reduction and internal fixation? Mid-term follow-up.

OBJECTIVE: To compare the mid-term outcomes in intra-articular distal humerus fracture (AO/OTA type C) treated with either open reduction-internal fixation (ORIF) or total elbow arthroplasty (TEA) in patients older than 75 years and with more than five years of follow-up. METHODS: Retrospective study including 24 patients (11 TEA vs. 13 ORIF) with a mean age of 82 years and being all females. Results assessed included (1) radiographic measures; (2) functional results: range of motion, Mayo Elbow Performance Score (MEPS), quick-DASH; and (3) complications. RESULTS: TEA group vs. ORIF group achieved a mean flexion of 117° ± 9.6° vs. 106° ± 14°, extension loss of 38° ± 17° vs. 30.8° ± 16°, pronation 75° ± 5° vs. 85° ± 7° and supination 75° ± 4° vs. 70° ± 5°. Mean MEPS score was 71.6 vs. 83.6 (p = .183) and mean quick-DASH was 44.8 vs. 42.6 (p = .789). All 13 patients in the ORIF group demonstrated radiographic signs of bone union and none underwent conversion to TEA. Sixty-three percent of the patients in the TEA group underwent re-operation at an average of 72 months (62.4-75.2 months), including three  for periprosthetic fracture and four  for implant loosening. Whereas in the ORIF group, 23% of the patients were re-operated upon excluding olecranon osteotomy hardware, two  for stiffness, and one  for an olecranon tension band wire failure. CONCLUSIONS: Although there were no differences in mid-term functional outcomes between either treatment, our results suggest that the recent trend towards the use of TEA instead of ORIF in the elderly should be re-examined due to the high rate of complications beyond five  years of follow-up with TEA.

Radiographic changes around the glenoid component in primary reverse shoulder arthroplasty at mid-term follow-up.

BACKGROUND: Some local events after reverse shoulder arthroplasty (RSA) occur without the patient experiencing symptoms and yet may be detected on diagnostic imaging, thereby serving as indicators of future complications that may require revision. Most of these events involve the glenoid component, but radiographic studies evaluating this component are scarce, especially medium- and long-term studies. This study aimed to analyze the radiographic changes around the glenoid component and determine the risk factors associated with the presence of these radiographic changes. MATERIALS AND METHODS: A retrospective review of 105 primary Grammont-style RSAs implanted between 2003 and 2014 was conducted. Radiographic outcomes were evaluated in patients with ≥5 years of radiographic follow-up. Standardized digital radiographs obtained immediately postoperatively and at a minimum follow-up time of 5 years were analyzed to determine (1) glenoid component position (inclination and height) and (2) minor radiographic changes (Sirveaux grade 1 or 2 scapular notching; nondisplaced acromial fracture; radiolucent lines around 1 or 2 screws; Brooker grade 1a, 1b, or 2 heterotopic calcifications; or single screw rupture), as well as major radiographic changes (Sirveaux grade 3 or 4 scapular notching; radiolucent lines around ≥3 screws or central peg; Brooker grade 1c or 3 heterotopic calcifications; prosthetic dislocation; loosening or migration; or disassembly). RESULTS: Major radiologic changes were identified in 14.3% of the cases. Bivariate analysis showed that more changes were associated with the arthroplasties implanted in the first years of the study (odds ratio [OR] = 0.81, P = .012). This time-related variable was also associated with inclination (OR = 0.88, P = .045) and height (OR = 0.75, P = .001), improving in arthroplasties implanted in the last years of the study. Multivariate analysis revealed an increased risk of severe scapular notching mainly associated with superior tilt (OR = 2.52, P = .036) and a high (OR = 2.68, P = .019) or excessively high (OR = 7.55, P = .013) position and an increased risk of loosening signs associated with superior tilt (OR = 8.92, P = 9.1 × 10-6). CONCLUSIONS: The percentage of radiologic changes of the glenoid component in RSA is considerable, despite the detection of a decrease in their presence among the arthroplasties implanted outside the initial period. Superior tilt and an excessively high position appear to be associated with a severe degree of scapular notching development and increased risk of radiographic loosening signs. Knowledge of the factors associated with major radiologic changes in the medium-term follow-up will help to optimize the primary surgical technique for each patient and indication, improving implant survival in primary RSA surgery.

Catalytic Oxidation of CO on a Curved Pt(111) Surface: Simultaneous Ignition at All Facets through a Transient CO-O Complex*.

The catalytic oxidation of CO on transition metals, such as Pt, is commonly viewed as a sharp transition from the CO-inhibited surface to the active metal, covered with O. However, we find that minor amounts of O are present in the CO-poisoned layer that explain why, surprisingly, CO desorbs at stepped and flat Pt crystal planes at once, regardless of the reaction conditions. Using near-ambient pressure X-ray photoemission and a curved Pt(111) crystal we probe the chemical composition at surfaces with variable step density during the CO oxidation reaction. Analysis of C and O core levels across the curved crystal reveals that, right before light-off, subsurface O builds up within (111) terraces. This is key to trigger the simultaneous ignition of the catalytic reaction at different Pt surfaces: a CO-Pt-O complex is formed that equals the CO chemisorption energy at terraces and steps, leading to the abrupt desorption of poisoning CO from all crystal facets at the same temperature.

Reverse shoulder arthroplasty versus nonoperative treatment for 3- or 4-part proximal humeral fractures in elderly patients: a prospective randomized controlled trial.

BACKGROUND: Proximal humeral fractures (PHFs) are among the most common fractures in elderly patients, but there is insufficient evidence from randomized controlled trials (RCTs) to determine which interventions are the most appropriate for their management. To date, no RCT has directly compared reverse shoulder arthroplasty (RSA) with nonoperative treatment for 3- or 4-part PHFs in elderly patients. METHODS: This was a prospective RCT. The primary objective was to compare pain and function 12 months after fracture using the Constant score in patients aged 80 years or older with 3- and 4-part PHFs, treated by either RSA or nonoperative treatment. Secondary outcome measures included Disabilities of the Arm, Shoulder and Hand, visual analog scale (VAS), Short Form 12 (SF-12), EuroQol 5 Dimensions, and EQ-VAS scores. RESULTS: We analyzed 30 nonoperative and 29 RSA patients with mean ages of 85 years and 82 years, respectively. No differences between the nonoperative and RSA groups were noted for any patient-reported outcomes at 12 months' follow-up except the VAS pain score. The Constant scores were 55.7 in the nonoperative group and 61.7 in the RSA group (P = .071); the Disabilities of the Arm, Shoulder and Hand scores were 29 and 21, respectively (P = .075); the VAS scores were 1.6 and 0.9, respectively (P = .011); the physical SF-12 scores were 36 and 37, respectively (P = .709); the mental SF-12 scores were 43 and 42, respectively (P = .625); the EuroQol 5 Dimensions scores were 0.89 and 0.92, respectively (P = .319); and the EQ-VAS scores were 65 and 67, respectively (P = .604). CONCLUSIONS: This study yields important evidence for the treatment of complex PHFs in elderly patients suggesting minimal benefits of RSA over nonoperative treatment for displaced 3- and 4-part PHFs. At short-term follow-up, the main advantage of RSA appeared to be less pain perception.