The host galaxy of a fast radio burst.

In recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be used for fundamental physical investigations. Every fast radio burst has a dispersion measurement, but none before now have had a redshift measurement, because of the difficulty in pinpointing their celestial coordinates. Here we report the discovery of a fast radio burst and the identification of a fading radio transient lasting ~6 days after the event, which we use to identify the host galaxy; we measure the galaxy's redshift to be z = 0.492 ± 0.008. The dispersion measure and redshift, in combination, provide a direct measurement of the cosmic density of ionized baryons in the intergalactic medium of ΩIGM = 4.9 ± 1.3 per cent, in agreement with the expectation from the Wilkinson Microwave Anisotropy Probe, and including all of the so-called 'missing baryons'. The ~6-day radio transient is largely consistent with the radio afterglow of a short γ-ray burst, and its existence and timescale do not support progenitor models such as giant pulses from pulsars, and supernovae. This contrasts with the interpretation of another recently discovered fast radio burst, suggesting that there are at least two classes of bursts.

Arthroscopic repair of subscapularis tears: preliminary data from a prospective multicentre study.

BACKGROUND: Until the introduction of arthroscopic-assisted surgery for rotator cuff repair, the frequency of subscapularis tears was underestimated. These tears remain challenging to treat even with arthroscopy. The absence of a specific classification system has hampered communication about the treatment and outcomes of the various types of subscapularis tears. The objective of this prospective multicentre study was to validate the relevance of arthroscopic subscapularis tendon repair based on an assessment of short-term outcomes according to the initial extent of the anatomic lesions. METHODS: A prospective multicentre study sponsored by the French Society for Arthroscopy was conducted from March 2010 to January 2011 in 208 patients with subscapularis lesions that were either isolated or associated with limited anterosuperior tears. The Constant and UCLA scores were used to assess clinical outcomes. Anatomic and prognostic results were evaluated based on the physical examination, preoperative and postoperative imaging study findings, and anatomic lesions. Clinical data were available for 103 patients after at least 1 year of follow-up and radiological data for 129 patients after at least 6 months. RESULTS: The preliminary clinical results in 103 patients with at least 1 year of follow-up showed overall statistically significant improvements in the Constant and UCLA scores, with resolution of the clinical manifestations. The degree of improvement seemed to increase over time. The clinical results varied significantly across patient groups based on a classification system distinguishing four lesion types. Postoperative imaging studies to assess the anatomic results in all patients with at least 6 months of follow-up (n=129) showed tendon healing in 92% of cases but also indicated muscle wasting of the upper subscapularis muscle in 18.6% of cases and increased fatty degeneration of the muscle belly. DISCUSSION: Our study confirms the good clinical and radiological results reported in the literature. Our classification system distinguishing four lesion patterns was applicable during the imaging workup. The main finding from this classification system was the difference in results between Type 2 and Type 3 lesions. The trend towards improvements over time requires confirmation by longer-term studies, which will also have to establish that the increased wasting of the upper subscapularis muscle and fatty degeneration of the muscle belly have no adverse effects.

Diagnosis of subscapularis tendon tears: are available diagnostic tests pertinent for a positive diagnosis?

HYPOTHESIS: Clinically, subscapularis tendon tears are suggested by the presence of increased passive external rotation compared to the opposite side, resisted internal rotation manoeuvres (Lift-Off test [LOT], Belly-Press test [BPT], Napoleon test and Bear-Hug test [BHT] and positive Internal Rotation Lag Sign and/or Belly-Off Signs). Associated bicipital involvement is frequent with subscapularis tendon tears, because it participates in the formation of the biceps pulley. The Palm-Up test (PUT) is used for the biceps, and the Jobe test for the supraspinatus. MATERIAL AND METHODS: In this multicenter study, we evaluated the positive diagnostic value of the clinical tests, LOT, BPT, BHT, PUT, and the Jobe test for subscapularis tears as well as their anatomical value. The relationships of the different parameters studied were compared statistically by analysis of variance (ANOVA). This prospective multicenter study was performed from January 2009 to February 2010 and included 208 cases of subscapularis tendon tears, isolated or associated with partial (Ellman 1, 2 or 3) or full thickness (SFA stage 1) supraspinatus tears. RESULTS: The severity of the subscapularis tear was quantified according to the SFA classification into four stages and according to the level of injury (the lower 1/3 and upper 2/3). The three tests LOT, BPT and BHT were correlated to the severity of observed tears (P<0.05). The more deficient the test results were, the more severe the anatomical damage. The LOT is the test that cannot be performed most often (18%) but when it is positive, it is predictive of very severe tears. The BHT is the most sensitive of all tests (82%). The frequency of biceps involvement was correlated to the severity of subscapularis damage. There was no significant correlation between biceps involvement and subscapularis tests, or between supraspinatus involvement and subscapularis tests. There was no correlation between the Palm-Up test and subscapularis tears with associated supraspinatus involvement however, it was significantly correlated to biceps involvement (P<0.05). The Jobe test was disappointing because it was often positive even for isolated subscapularis tears. CONCLUSION: Even though all three tests were performed (LOT, BPT, BHT), 24% of the subscapularis tears were only diagnosed during surgery. The role of the Internal Rotation Lag Sign and Belly-Off Sign in improving the diagnosis of tears was not studied in this work.

New endoscopic classification for subscapularis lesions.

BACKGROUND: The absence of a coherent classification system has hampered communication about the treatment and outcomes of the various types of subscapularis tendon lesions. In addition, a reliable classification system allows comparisons of epidemiological and therapeutic data. The classification systems used until now fail to incorporate the radiological and intraoperative abnormalities of the bicipital sling, and they do not consider the degree of subscapularis tendon cleavage. Here, we describe a new arthroscopy-based classification system intended for therapeutic and prognostic purposes. METHODS: A prospective multicentre study sponsored by the French Society for Arthroscopy was conducted from March 2010 to January 2011 in 150 isolated subscapularis lesions with or without limited anterosuperior involvement. The bicipital sling and insertion of the deep subscapularis layer were routinely investigated by arthroscopy with video recording. Each lesion was classified after a consensus was reached among four surgeons. RESULTS: We identified four lesion types based on the bicipital sling findings. Type I was defined as partial separation of the subscapularis tendon fibres from the lesser tuberosity with a normal bicipital sling. Type II consisted of a partial subscapularis tear at the lesser tuberosity attachment combined with partial injury to the anterior wall of the bicipital sling, without injury to the superior glenohumeral ligament. Type III was complete separation of the subscapularis fibres from the lesser tuberosity with extensive cleavage of the bicipital sling. Finally, in Type IV, all the subscapularis fibres were detached and, in some cases, conjunction of the subscapularis and supraspinatus fibres produced the comma sign. Nearly all the lesions identified intraoperatively during the study fit one of these four types. DISCUSSION: A reproducible classification system that allows different surgeons to establish comparable homogeneous patient groups is useful for both therapeutic and prognostic purposes. We defined four types of subscapularis lesions that are easy to identify as either isolated lesions or combined with anterosuperior rotator cuff tears. Long head of biceps tendon abnormalities and fatty degeneration of the shoulder muscles can be added to our classification system. Studies of intraobserver and interobserver reproducibility are needed to complete the process of validating the diagnostic and/or prognostic usefulness of this new classification scheme.

A study of reproducibility of an original method of CT measurement of the lateralization of the intertubercular groove and humeral retroversion.

An original method of CT measurement of the lateralization of the humeral intertubercular groove is described based on geometric construction following Thales theorem. A study of intra- and interobserver reproducibility was done of this measurement and humeral retroversion on 32 healthy volunteers. The results show good reproducibility of these measurements. The average value of humeral retroversion was lower than the average values found in the literature: 11.71 degrees on average on the dominant side and 7.03 degrees on average on the non-dominant side with a large spread of values. The reasons for these differences are discussed. The average values of lateralization of the intertubercular groove were 114.97 degrees on the dominant side and 121.9 degrees on the non-dominant side. These CT measurements are important to consider in the pathophysiology of chronic anterior instability of the shoulder.

[Arthroplasty with a mobile cup for shoulder arthrosis with irreparable rotator cuff rupture: preliminary results and cineradiographic study]. / L'arthroplastie à cupule mobile dans l'omarthrose avec rupture de coiffe irréparable: résultats préliminaires et étude radiocinématographique.

PURPOSE OF THE STUDY: Management of patients with massive irreparable rotator cuff tears associated with severe glenohumeral joint degeneration presents a difficult clinical challenge. The present study reports on 24 patients with disabling shoulder pain due to rotator cuff arthropathy treated using a bipolar arthroplasty. MATERIAL AND METHODS: Between 1995 and 1997, a bipolar shoulder arthroplasty (Biomet, Warsaw, In) was used in 24 patients (25 shoulders) with rotator cuff arthropathy. Patients were monitored for an average of 14.5 months (range 12 to 24 months). The coracoacromial ligament was maintained in all patients to provide anterosuperior stability. The rotator cuff was irreparable and no attempt was made to cover the superior defect. Postoperative results were reviewed with the Constant score and the Swanson score. In order to verify the head-shell motion and to analyze the dynamic comportement of bipolar arthroplasties, we recorded anterior active elevation and active rotations with video-fluoroscopy. RESULTS: At final the follow-up, 21 shoulders had no or slight pain. Average active flexion improved to 84.8 degrees after operation from 62.4 degrees beforehand. 13 patients achieved more than 90 degrees of active flexion after operation. Active external rotation improved from a mean 3 to 28.8 degrees. Before surgery the average Constant score was 17.62. Postoperatively, the average Constant score was 46.97 and the average Swanson score was 23.13. Complications requiring reoperation occurred in 2 cases: 1 component dislocation (Head-shell), 1 subluxation of the long head of the biceps. Radiographic evaluation at follow up demonstrated no humeral stem loosening or component migration and no bony erosion of the coracoacromial arch. Rupture of the infraspinatus tendon (absolute Constant score: p = 0.04, adjusted Constant score: p = 0.02, Swanson score: p = 0.03, Functional score: p = 0.04), preoperative anterior subluxation of the humeral head (absolute Constant score: p = 0.03, adjusted Constant score: p = 0.05, anterior elevation: p = 0.01, functional score: p = 0.04), preoperative narrowing of the acromio-humeral interval (adjusted Constant score: p = 0.02, overall mobility: p = 0.02, anterior elevation: p = 0.03) may jeopardize the subsequent success of bipolar shoulder arthroplasty. The results of this study suggest that the radius curvature of the shell must match that of the bony surface of the glenoid and the coracoacromial arch (absolute Constant score: p = 0.003, adjusted Constant score: p = 0.005, overall mobility: p = 0.002, anterior elevation: p = 0.0008, functional score: p = 0.002). Recording of anterior active elevation with video-fluoroscopy allowed to identify 3 different types of movements after bipolar shoulder arthroplasty. Recording of internal and external rotation allowed to distinguish 2 differents types of movements. Motion appeared to occur between the bipolar shell and the head. The amount of motion was variable and depended on the biomechanics. DISCUSSION AND CONCLUSION: Bipolar shoulder arthroplasty is an effective surgical option for patients with massive irreparable tears of the rotator cuff with concomitant glenohumeral arthritis. Satisfactory pain relief and modest gains in motion result in significant functional improvement in this "low functional demand" population. Predictive factors have been identified and should be discussed before surgery.

[Clinical and radiologic outcome of humeral implants in shoulder arthroplasty]. / Devenir clinique et radiologique des implants huméraux des arthroplasties d'épaule.

The clinical and radiological evolution of the glenoid socket in total shoulder arthroplasty is well documented, whereas evaluation of the humeral component has received much less attention. The outcome of 40 humeral replacements performed in 39 patients was studied with a minimum follow-up of one year. There were 26 Neer prostheses, 9 Modular Shoulder prostheses and 5 Aequalis prostheses. Twenty-nine prostheses were implanted with cement and 11 were cementless. The clinical and radiological results were assessed according to the scoring system used for the 1994 symposium of SO.F.C.O.T. X rays in the coronal plane were used to assess the position of the stem, radiolucencies around the humeral component and the percentage of the cross-section of the diaphysis filled by the humeral stem. The average follow-up period was respectively 55.6 months for the Neer prostheses, 17.9 months for the Modular Shoulder prostheses and 12.4 months for the Aequalis prostheses. Radiolucent lines were noted in 20 cases, all with uncemented humeral components. Two prostheses were loose; however, none required revision. The underlying pathology, surgical approach, position of the humeral component, implant design or association with glenoid resurfacing were not correlated with the presence of radiolucent lines or with a loose implant. Cementless fixation was the only parameter statistically related with the presence of radiolucent lines. This report confirms the good results obtained with cemented humeral prostheses. Radiological evaluation of the smooth cementless humeral implant showed many progressive radiolucent lines, without clinical expression. The authors analyze the various studies in the literature and discuss the interest of cementless implants with ingrowth surface.

[Long-term results of proximal osteocartilaginous autografts in extensive cartilagenous destruction of the knee. Apropos of 5 cases]. / Résultats a long terme de l'autogreffe ostéo-cartilagineuse de voisinage dans les destructions cartilagineuses etendues du genou. A propos de 5 cas.

Five patients with a large defect in the articular cartilage at the knee joint were treated by transplantation of an autogenic osteochondral fragment. The graft was harvested from the posterior portion of the ipsilateral femoral condyle in 4 cases of osteochondritis dissecans, and from the lateral third of the patella pedicled on the patellar ligament in one case of posttraumatic necrotic collapse of the lateral tibial plateau. One patient underwent concomitant high tibial osteotomy. Two months postoperatively bony union was achieved in all cases but in one case, the grafted articular cartilage did not survive after weight bearing because of an overlooked varus deformity. At the follow-up examination (8 to 20 years) all 5 patients were asymptomatic ; the range of flexion was somewhat restricted (120 degrees) ; roentgenogram revealed slight narrowing of the articular space or at least flattening of the grafted zone and subchondral osteosclerosis. At arthroscopic exploration, the grafted zones were recognizable from the surrounding cartilage, and histologic examination of their border revealed fibrocartilage and proliferating vessels; late gonarthrosis might ensue over time. Therefore the procedure should be performed only in large osteochondral defects where neither reattachment of a loose body, nor hemiarthroplasty, nor isolated osteotomy are suitable and before degenerative changes have developed. Morever any associated varus deformity requires concomitant correction by high tibial osteotomy to relieve stress from the graft.

[Is calcaneal osteotomy justified in Haglund's disease?]. / L'Ostéotomie calcanéenne est-elle justifiée dans la maladie de Haglund?

PURPOSE OF THE STUDY: The authors report their experience of Zadek's wedge osteotomy in the treatment of posterior talalgia in adults and evaluate the various radiographical measurements for calcaneus deformity measurement.... MATERIAL: This procedure was performed in 27 patients with a total of 36 calcanea treated between 1985 and 1996. The sex ratio was 20 women for 7 men with an average age of 27 years. Prior to this osteotomy nine feet were operated by resection of the postero-superior tuberosity with recurrence of pain and disability, and two patients presented an inflammatory arthritis. METHOD: For the surgical procedure, the patient was placed in lateral position. Skin incision was five to six centimeters long, curvilinear along the lateral side of the tendo achillis. Two dorsal pins were inserted, creating a triangle so that the apex pointed plantarly and the base dorsally. The sagittal saw was then used to create a wedge osteotomy with a dorsal base of seven to ten millimeters. A screw was then driven across the osteotomy site for ultimate fixation. RESULTS: Eighty per cent (29 osteotomies) of patients had been examined clinically and radiologically with a mean follow-up of 29 months. Considering pain, daily activity and discomfort with footwear, results were excellent in 12 cases, good in 10, fair in 5 and poor in two cases. No radiological criteria used for the diagnosis of Haglund's disease were absolutely reliable. The "total angle" of Ruch, the "c.l angle" of Chauveaux and the "parallel pitch lines" of Heneghan reflect the amount of deformation most accurately, but especially, the calcaneal inclination angle was always increased (16 cases between 18 degrees and 30 degrees, 6 cases > 30 degrees). All patients had a weight-bearing calcaneal talus, either alone or in the context of posterior pes cavus. CONCLUSION: This study confirms the responsibility of rearfoot morphostatic disorders in posterior talalgia and the goods results obtained by Zadek osteotomy.

[Surgical treatment of the rheumatoid forefoot by realignment using th dorsal approach]. / Traitement chirurgical de l'avant-pied rhumatoïde par alignement par voie dorsale.

PURPOSE OF THE STUDY: The aim of this study was to appreciate the results of the modified Fowler's procedure in the surgical treatment of forefoot deformities due to rheumatoid arthritis. MATERIAL AND METHOD: If the principles of the metatarsophalangeal resection through a dorsal transverse incision were conserved, we progressively modified the initial procedure with renunciation to the plantar skin incision, preservation of a skin bridge between the medial and transverse dorsal approach, using centro medullary pins to hold in position toes alignment and making an arthrodesis of the first metatarsophalangeal joint. Ten patients (17 surgical procedures) were clinically and roentgenographically reviewed at an average follow-up of 27.3 months (Range : 12 and 53 months). RESULTS: Clinical results according to the Gainor scale showed an increase of the overall score from 3.4 points to 11.2 points at revision. Twelve foot were rated excellents and five goods. Seventy per cent of patients had no pain and 58 per cent used a normal footwear. Radiographical and clinical analysis showed that an egyptian foot remained in nine cases, podoscopic examination revealed frequently a lack of footrest on lateral toes without functional implications. Delayed wound healing were observed in four cases with good evolution. CONCLUSION: With this surgical procedure, our functional results were encouraging and we recommend it in severe deformities of the rheumatoid foot with fixed metatarsophalangeal dislocations and bone defect of the metatarsal heads.

[Effect of the rotator cuff condition on the results of shoulder arthroplasty]. / Influence de l'état de la coiffe des rotateurs sur les résultats de l'arthroplastie d'épaule.

PURPOSE OF THE STUDY: The purpose of this report was to study the repercussions of rotator cuff condition on unconstrained shoulder arthroplasty results. METHODS: Between 1986 and 1993, 40 unconstrained shoulder prostheses were performed (24 total and 16 hemiarthroplasties). At the time of the operation, rotator cuff condition was reported to be normal in 15 shoulders, atrophic in 10, scarred in 3, torn in 12. Clinical and radiographical results were analyzed and supplemented with a rotator cuff echography. Postoperative follow-up averaged 42.25 months (12 to 97 months). RESULTS: When the rotator cuff was intact at the time of operation, clinical results were the best at the time of review. Constant score, overall mobility, forward elevation, external rotation with the elbow along the side were better for intact than for atrophic, scarred or torn rotator cuffs (p < 0.01). Ruptures repaired by local tissue transfer or trapezo deltoidal flap substitution (3 cases) gave satisfactory results, whereas two dacron cuff prostheses failed. In the non repaired ruptures (7 cases), arthroplasty resulted in 3/4 fair or poor results. At the time of review, the total incidence of postoperative rotator cuff tears was high (12 cases), functional repercussions were variable. Among the 15 rotator cuff tears observed at the time of the review, the long head of the biceps was present and in place in 9 cases and ruptured in 6 cases. In these latter cases, Constant score (p < 0.01), the forward elevation (p < 0.01), external rotation with elbow along side (p < 0.05) and overall mobility (p < 0.05) were worse; moreover, humeral head superior migration was greater (p < 0.01). DISCUSSION: Our study confirms the superiority of clinical results when the cuff was intact at the time of the operation. The repair of rotator cuff tears seems to be justified. When the rupture has not been repaired, clinical results were fair or poor in 5 cases out of 7, the initial rupture spread to the other tendons in 3 cases out of 7. Secondary ruptures were frequent (12 cases). No predictive factor was identified, but an overlapping of the greater tuberosity appears to be detrimental. Among rotator cuff tears present at the time of review, long head of the biceps rupture jeopardized clinical results and was associated with a proximal migration of the humeral head which was significantly more severe than with an intact non displaced long head of the biceps. CONCLUSION: During unconstrained shoulder prosthesis implantation, it is therefore recommend to systematically repair any associated rotator cuff rupture, in order to avoid any greater tuberosity overlap relative to the prosthetic head and to preserve the long head of the biceps tendon which limits upward migration of the humeral head and improves prosthetic kinetics.