Restoration of Internal Rotation After Reverse Shoulder Arthroplasty May Vary Depending on Etiology in Patients Younger Than 60 Years Old: A Multicenter Retrospective Study.

BACKGROUND: Reverse shoulder arthroplasty (RSA) offers promising functional outcomes for young patients, yet challenges persist in restoring internal rotation (IR). This study aimed to assess the restoration of IR after RSA in patients younger than 60 years old and analyze the factors affecting IR recovery. METHODS: A retrospective multicenter study was conducted, examining the functional outcome of patients who underwent RSA, with a minimum follow-up period of 2 years. Two subgroups of patients who underwent primary RSA were analyzed separately with respect to active (AIR1): "difficult AIR1" and "easy AIR1." RESULTS: The study included 136 patients (overall series) with a mean age of 51.6 years. The overall series showed statistically significant improvement in active range of motion (RoM), pain, and Constant scores, especially with active IR (p<0.01). According to etiology, statistically significant improvement (p<0.05) in active IR was observed for fracture sequelae, primary osteoarthritis, and rheumatoid arthritis, while no statistically significant improvement in internal rotation was observed for tumor, revision, and cuff tear arthropathy (p>0.05). In subgroup analysis, patients with easy AIR1 displayed a statistically significant lower body mass index and better Constant score mobility, as well as improved motion in forward elevation and active IR (p<0.05). No statistically significant associations were found between improved IR and prosthetic design or subscapularis repair. Scapular notch, lysis of the graft, and teres minor atrophy were significantly associated with better active IR (p<0.05). CONCLUSION: RSA improves active RoM, pain, and functional outcomes in patients under 60. However, the degree of improvement in IR may vary depending on several factors and the underlying etiologies. These insights are crucial for patient selection and counseling, guiding RSA optimization efforts. LEVEL OF EVIDENCE: IV.

Infected Shoulder Arthroplasty in Patients Younger than 60 Years: Results of a Multicenter Study.

Background: Periprosthetic joint infection (PJI) after shoulder arthroplasty remains a significant complication. This study aimed to explore the epidemiology and risk factors of shoulder PJI in patients aged 60 and younger, analyze treatment options, and evaluate outcomes after 1-year follow-up. Methods: In this retrospective multicentric observational study, data from 1404 shoulders in patients under 60 who underwent primary shoulder arthroplasty were analyzed. Patients with PJI and at least 1-year follow-up after infection treatment were included. Results: The study identified 55 shoulders with PJI, resulting in a 2.35% infection rate after primary shoulder arthroplasty in the young population. Male gender and reverse shoulder arthroplasty were risk factors for infection, while previous surgeries did not significantly contribute. The most common causative agents were Cutibacterium acnes and Staphylococcus epidermidis. Open washout had a 52.9% success rate for acute infections, while one-stage and two-stage revisions achieved infection control rates of 91.3% and 85.7%, respectively. Resection arthroplasty had an 81.8% success rate but poorer functional outcomes. Conclusions: PJI following shoulder arthroplasty in young patients is a significant concern. Preoperative planning should be carefully considered to minimize infection risk. Treatment options such as open washout and one-stage and two-stage revisions offer effective infection control and improved functional outcomes. Resection arthroplasty should be reserved for complex cases where reimplantation is not a viable option.

Predictive factors of return-to-work trajectory after work-related rotator cuff syndrome: A prospective study of 96 workers.

OBJECTIVE: Sustained return to work after surgery for work-related rotator cuff syndrome (WRRCS) remains quite difficult. The main purpose of the present study was to identify predictive factors of a return-to-work (RTW) trajectory. METHODS: A total of 96 workers with WRRCS were identified by 4 surgeons. They were followed prospectively before and after the surgery, until 1 year after RTW, or for 20 months after surgery when they did not. Participants completed a series of standardized questionnaires related to working conditions, health, and beliefs, and performed functional tests at the inclusion time. During the follow-up period, they were regularly asked about their working conditions (present or not at work), activity (normal or lightened physical duties) and schedules (full- or part-time job). Statistical analysis was based on single- and multiple-factor models of prediction of the workers' trajectory. RESULTS: Three trajectories of RTW were distinguished, considering RTW and absenteeism that occurred during the follow-up: stable, unstable, and non-RTW. The median age of the sample was 49.5 [45.0-54.0], with 67.7% of workers employed in highly physically demanding jobs. In the multiple factor model, three factors were highly predictive of the trajectory: perceived health before surgery, having had a repaired ruptured-rotator-cuff tendinopathy, and the level of physical demand of the job. CONCLUSION: Three easy-to-collect predictive factors of RTW trajectory have been identified. They may be useful for healthcare professionals and care givers to identify vulnerable workers' risk of occupational dropout after arthroscopic surgery for rotator cuff tendinopathy.

The Real Post-Operative Range of Motion Differs from the Virtual Pre-Operative Planned Range of Motion in Reverse Shoulder Arthroplasty.

INTRODUCTION: The purpose of this study was to analyze the real range of motion (RoM) measured in patients operated on for reverse shoulder arthroplasty (RSA) and compare it to the virtual RoM provided by the preoperative planning software. HYPOTHESIS: There was a difference between virtual and real RoM, which can be explained by different factors, specifically the scapula-thoracic (ST) joint. METHODS: Twenty patients with RSA were assessed at a minimum follow-up of 18 months. Passive RoM in forward elevation abduction, without and with manually locking the ST joint, and in external rotation with arm at side were recorded. The humerus, scapula, and implants were manually segmented on post-operative CTs. Post-operative bony structures were registered to preoperative bony elements. From this registration, a post-operative plan corresponding to the real post-operative implant positioning was generated and the corresponding virtual RoM analysis was recorded. On the post-operative anteroposterior X-rays and 2D-CT coronal planning view, the glenoid horizontal line angle (GH), the metaphyseal horizontal line angle (MH), and the gleno-metaphyseal angle (GMA) were measured to assess the extrinsic glenoid inclination, as well as the relative position of the humeral and glenoid components. RESULTS: There were some significant differences between virtual and post-operative passive abduction and forward elevation, with (55° and 50°, p < 0.0001) or without ST joint participation (15° and 27°, p < 0.002). For external rotation with arm at side, there was no significant difference between planning (24° ± 26°) and post-operative clinical observation (19° ± 12°) (p = 0.38). For the angle measurements, the GMA was significantly higher (42.8° ± 15.2° vs. 29.1°± 18.2°, p < 0.0001), and the GH angle, significantly lower on the virtual planning (85.2° ± 8.8° vs. 99.5° ± 12.5°, p < 0.0001), while the MH was not different (p = 0.33). CONCLUSIONS: The virtual RoM given by the planning software used in this study differs from the real post-operative passive RoM, except for external rotation. This can be explained by the lack of ST joint and soft tissues simulation. However, in focusing on the virtual GH participation, the simulation looks informative. Some modifications between the glenoid and humerus starting positions before running the motion analysis could be provided for making it more realistic and predictive of the RSA functional results. LEVEL OF EVIDENCE: III.

Anatomical plane and transverse axis of the scapula: Reliability of manual positioning of the anatomical landmarks.

Background: The aim of our study was to evaluate the accuracy of manual determination of the three key points defining the anatomical plane of the scapula, which conditions the reliability of planning software programs based on manual method. Method: We included 82 scapula computed tomography scans (56 pathologic and 26 normal glenoid), excluding truncation and major three-dimensional artifact. Four observers independently picked the three key points for each case. Inter- and intra-observer agreement was calculated for each point, using the intraclass correlation method. The mean error (mm) between the observers was calculated as the diameter of the smallest sphere including the four chosen positions. Results: Lower inter-observer agreement was found for the trigonum superoinferior position and for the glenoid center anteroposterior position. The mean positioning error between the four observers was 6.9 mm for the trigonum point, and error greater than 10 mm was recorded in 25% of the cases. The mean positioning error was 3.5 mm for the glenoid center in altered glenoid, compared to 1.8 mm for normal glenoid. Discussion: Manual determination of an anatomical plane of the scapula suffers from inaccuracy especially due to the variability in trigonum picking, and in a lesser extent, to the variability of glenoid center picking in altered glenoid.

Glenoid Inclination: Choosing the Transverse Axis Is Critical-A 3D Automated versus Manually Measured Study.

The aim of this study was to evaluate the variation in measured glenoid inclination measurements between each of the most used methods for measuring the scapular transverse axis with computed tomography (CT) scans, and to investigate the underlying causes that explain the differences. METHODS: The glenoid center, trigonum and supraspinatus fossa were identified manually by four expert shoulder surgeons on 82 scapulae CT-scans. The transverse axis was generated either from the identified landmarks (Glenoid-Trigonum line (GT-line), Best-Fit Line Fossa (BFLF)) or by an automatic software (Y-axis). An assessment of the interobserver reliability was performed. We compared the measured glenoid inclination when modifying the transverse axis to assess its impact. RESULTS: Glenoid inclination remained stable between 6.3 and 8.5°. The variations occurred significantly when changing the method that determined the transverse axis with a mean biase from -1.7 (BFLF vs. Y-axis) to 0.6 (BFLF vs. GT-line). The Y-axis method showed higher stability to the inclination variation (p = 0.030). 9% of cases presented more than 5° of discrepancies between the methods. The manual methods presented a lower ICC (BFLF = 0.96, GT-line = 0.87) with the widest dispersion. CONCLUSION: Methods that determine the scapular transverse axis could have a critical impact on the measurement of the glenoid inclination. Despite an overall good concordance, around 10% of cases may provide high discrepancies (≥5°) between the methods with a possible impact on surgeon clinical choice. Trigonum should be used with caution as its anatomy is highly variable and more than two single points provide a better interrater concordance. The Y-axis is the most stable referential for the glenoid inclination.

Can surgeons optimize range of motion and reduce scapulohumeral impingements in reverse shoulder arthroplasty? A computational study.

Background: Early glenohumeral impingement leads to poor range of motion and notching in reverse shoulder arthroplasty. The aim was to find from planning software which implant configuration provides the best motions in reverse shoulder arthroplasty. Patients and Methods: Reverse shoulder arthroplasty planning (Glenosys) was made in 31 patients (12 men, 19 women, 76 ± 6 yo) and impingements were analyzed. Inlay (155°-inclined) and Onlay (145°-inclined) humeral designs were tested. Four configurations were tested for each shoulder: "INLAY": non-lateralized glenoid-inlay humerus, "BIO-INLAY": lateralized glenoid (BIO-RSA)-inlay humerus, "ONLAY": non-lateralized glenoid-onlay humerus, and "BIO-ONLAY": lateralized (BIO-RSA) glenoid-onlay humerus. Results: BIO-ONLAY and BIO-INLAY groups presented a significantly better result in all tested motion (p < 0.001 for all tests). BIO-ONLAY allowed a significantly better external rotation, extension and adduction than BIO-INLAY with decreased impingements with the pilar. BIO-INLAY presented a significantly better abduction. In abduction, an abutment of the greater tuberosity against the acromion was associated with a lower range of motion (p < 0.0001) and did not depend on the lateralization. Conclusion: Glenoid lateralization delays the glenohumeral impingement in reverse shoulder arthroplasty and gives the best rotations, adduction and extension when associated with neutral inclination and humeral 145° inclination. Greater tuberosity abutment has to be avoided in abduction and the Inlay design provides the best abduction.

The arm change position: Additional information for optimizing range of motion after reverse shoulder arthroplasty.

INTRODUCTION: The arm change position (ACP) is a new parameter for evaluating the humerus' 3D displacement following reverse shoulder arthroplasty (RSA) during 3D pre operative planning. The purpose of this study was to analyze the relationship between ACP variations after RSA and simulated passive joint mobility. The assumption is that the ACP will to help optimize the passive joint mobility of a RSA implant. METHODS: In 30 degenerative shoulders, four shoulder surgeons planned a RSA with virtual motion analysis. After this analysis, each plan was revised to optimize the range of motion. Relationships between the differences in movement amplitude and the differences in ACP were evaluated. RESULTS: Arm lengthening and humerus lateralization were significantly associated with better joint mobility in all three planes (frontal, sagittal and axial). They were equally important for improving external rotation, extension, flexion and adduction. Anterior displacement of the humerus improved both internal and external rotation. DISCUSSION: The ACP is a useful preoperative planning parameter for RSA. It could help with selecting the best implant combination, as well as determining their position, in order to optimize the simulated passive mobility relative to humerus displacement after RSA. To validate the value of the ACP in clinical practice, a prospective study is needed in which the postoperative joint mobility is measured in vivo as a function of the ACP. LEVEL OF EVIDENCE: III, case control study.

Preoperative planning of baseplate position in reverse shoulder arthroplasty: Still no consensus on lateralization, version and inclination.

INTRODUCTION: In the context of reverse shoulder arthroplasty, some parameters of glenoid baseplate placement follow established golden rules, while other parameters still have no consensus. The assessment of glenoid wear in the future location of the glenoid baseplate varies among surgeons. The objective of this study was to analyze the inter-observer reproducibility of glenoid baseplate 3D positioning during virtual pre-operative planning. METHOD: Four shoulder surgeons planned the glenoid baseplate position of a reverse arthroplasty in the CT scans of 30 degenerative shoulders. The position of the glenoid guide pin entry point and the glenoid baseplate center was compared between surgeons. The baseplate's version and inclination were also analyzed. RESULTS: The 3D positioning of the pin entry point was achieved within ± 4 mm for nearly 100% of the shoulders. The superoinferior, anteroposterior and mediolateral positions of the baseplate center were achieved within ± 2 mm for 77.2%, 67.8% and 39.4% of the plans, respectively. The 3D orientation of the glenoid baseplate within ± 10° was inconsistent between the four surgeons (weak agreement, K=0.31, p=0.17). DISCUSSION: The placement of the glenoid guide pin was very consistent between surgeons. Conversely, there was little agreement on the lateralization, version and inclination criteria for positioning the glenoid baseplate between surgeons. These parameters need to be studied further in clinical practice to establish golden rules. Three-dimensional information from pre-operative planning is beneficial for assessing the glenoid deformity and for limiting its impact on the baseplate position achieved by different surgeons. LEVEL OF EVIDENCE: III. Case control study.

Predictive factors for the duration until return to work after surgery for work-related rotator cuff syndrome: A prospective study of 92 workers.

BACKGROUND: Return to work (RTW) after surgery for a work-related rotator cuff disorder (WRRCD) is often difficult. The study's purpose was to identify preoperative factors predicting RTW. METHODS: Ninety-two workers with a WRRCD were identified by four surgeons. Before surgery, the workers completed a series of standardized questionnaires related to working conditions, health, and health beliefs. They were followed up prospectively for 20 months. Statistical analysis was based on single and multiple-factor Cox models of the duration of absence from the time of surgery until RTW. RESULTS: The median age at inclusion was 49 years (27-62), with 52 women included (57%). Sixty-one subjects (66%) were employed in highly physically demanding jobs. Forty-two (46%) stayed at work until their surgery, whereas preoperative sick leave exceeded 100 days in 20 subjects (21%). Twenty months after surgery, 14 were still not back at work. For the other participants, the mean duration until RTW was 225 days (SD 156). In the fully adjusted model, variables that were significantly predictive of the duration until RTW were: work physical demand levels, preoperative sick leave, the number of body parts causing pain or discomfort in the last 12 months, self-assessed 2-year workability, and the Readiness for RTW (RRTW) Scale. CONCLUSIONS: Several physical, psychological, and work-related factors, easily recorded, can be identified preoperatively. They may be predictive of delayed return, loss of employment, or employability as a result of shoulder surgery.

Traumatic Isolated Myotendinous Rupture of the Teres Minor in a Young Athlete - A Unique Case Report.

INTRODUCTION: Functional role of teres minor (TM) is well known. To date, an isolated myotendinous rupture of the TM, without any lesion of the other cuff tendons, has never been reported in literature. CASE REPORT: The patient was a 22-year-old soccer player who has presented with a direct shoulder traumatism that is causing persistent pain and impairment. Early appropriate imaging was done (magnetic resonance imaging [MRI] and arthro-computed tomography scan); it revealed an isolated tear of the TM at the myotendinous junction. Open surgical repair was performed through a posterior approach, within the 1st month after the injury. The patient was immobilized for 1 month in neutral rotation and then was allowed to begin the rehabilitation process. At the 2-year follow-up point, the patient had a pain-free and functional shoulder, allowing a return to full activities, including sport at the pre-injury level. MRI confirmed that the muscle had healed, without atrophy or fatty infiltration. CONCLUSION: A TM myotendinous tear is very rare but might be under diagnosed. Early appropriate imaging is necessary. Surgical repair may be the preferable option in young and active patients and should be performed at the acute phase before muscular atrophy and fatty infiltration occur.

Anteversion and length of the femoral tunnel in ACL reconstruction: in-vivo comparison between rigid and flexible instrumentation.

BACKGROUND: Due to it being tangential to the distal femoral axis, the anteromedial portal presents significant risk of causing iatrogenic damage, and of producing tunnels that are too short for optimal osseointegration. Flexible reamers were developed to eliminate the need for knee hyperflexion and offer better-controlled orientation of the femoral tunnel. We aimed to compare the anteversion and length of femoral tunnels drilled using flexible reamers to those drilled using rigid reamers. METHODS: Between May 2012 and December 2013, all patients receiving ACL reconstruction performed by one surgeon were operated on using either a rigid or a flexible reamer from the same supplier (Versi-Tomic® system, Stryker, Kalamazoo, Michigan). The height of each patient was recorded, and the length and anteversion of the femoral tunnels were measured intra-operatively and on true lateral radiographs, respectively. RESULTS: Thirty-seven patients underwent operations using the rigid instrumentation, and 43 using the flexible instrumentation. There was no statistically significant difference between the two groups in either sex or height (p = n.s.). The patients operated on using the rigid instrumentation had tunnels anteverted by 18.6° ± 6° and 33.6 ± 2.9 mm long. Those operated on using the flexible instrumentation had tunnels anteverted by 40° ± 2° and 41.1 ± 3.57 mm long. Both anteversion and tunnel length were significantly greater for tunnels drilled using the flexible instrumentation (p < 0.001). CONCLUSIONS: This study demonstrated that flexible reamers produce significantly more anteverted and longer femoral tunnels during ACL reconstruction than rigid reamers. Clinical studies remain necessary to assess the outcomes of ACL reconstruction using flexible reamers.

Proximal humeral bony adaptations with a short uncemented stem for shoulder arthroplasty: a quantitative analysis.

BACKGROUND: Short uncemented stems have recently been proposed as an alternative to classic long stems for shoulder arthroplasty. The early results are promising, but bony adaptations of the proximal humerus have been reported. The aim of this study was to quantify these phenomena using the Ascend Flex stem and to determine the risk factors. MATERIALS AND METHODS: In a retrospective, single-center study, 183 shoulder arthroplasties were evaluated at 2-year follow-up. All patients underwent clinical evaluations preoperatively and at last follow-up. Radiographs were obtained preoperatively, postoperatively, and at last follow-up. Four types of bony adaptations were analyzed: medial cortical narrowing (MCN), medial metaphysis thinning (MMT), lateral metaphysis thinning (LMT), and under-the-baseplate osteolysis. The risk factors were analyzed in a multivariate model. RESULTS: MCN was found in 72.6% of cases and was severe (>50%) in 4.4%. MMT was found in 46.4% of cases and was severe in 3.3%. LMT was found in 9.8% of cases and was severe in 2.8%. The risk factors for MCN were the distal filling ratio, osteoporosis, and female sex, whereas MMT and LMT were only influenced by stem axis deviation. Under-the-baseplate osteolysis was found in 34.4% of cases. No influence of bony adaptations on the clinical outcomes was observed. We found no complications related to the stem or to stem loosening. CONCLUSION: The radiographic evolution was satisfactory at mid-term follow-up. Bony adaptations seemed to be limited phenomena, without any observed consequence. Avoiding excessive filling and axis deviation may limit these phenomena.

Iliotibial band friction syndrome: An original technique of digastric release of the iliotibial band from Gerdy's tubercle.

The various surgical techniques to treat iliotibial band friction syndrome consist in releasing the iliotibial band by means of plasties that partially interrupt its continuity or by release of the deep aspect. We describe an original technique of digastric distal iliotibial band release from Gerdy's tubercle. Via a 2 cm approach above Gerdy's tubercle, the iliotibial band is incised longitudinally and partially released from the tubercle. Fourteen knees underwent the procedure. With a mean 27±20.6 months' follow-up (range, 12-69 months), return to sport at previous level was possible at a mean 4±2.18 months (range, 1-8 months). Eight patients were very satisfied, 3 satisfied and 2 (15%) dissatisfied. Respect of continuity is a key-point in this technique to control internal rotation of the knee.

Proper benefit of a three dimensional pre-operative planning software for glenoid component positioning in total shoulder arthroplasty.

PURPOSE: Glenoid loosening after total shoulder arthroplasty (TSA) is influenced by the position of the glenoid component. 3D planning software and patient-specific guides seem to improve positioning accuracy, but their respective individual application and role are yet to be defined. The aim of this study was to evaluate the accuracy of freehand implantation after 3D pre-operative planning and to compare its accuracy to that of a targeting guide. METHOD: Seventeen patients scheduled for TSA for primary glenohumeral arthritis were enrolled in this prospective study. Every patient had pre-operative planning, based on a CT scan. Glenoid component implantation was performed freehand, guided by 3D views displayed in the operating room. The position of the glenoid component was determined by manual segmentation of post-operative CT scans and compared to the planned position. The results were compared to those obtained in a previous work with the use of a patient-specific guide. RESULTS: The mean error for the central point was 2.89 mm (SD ± 1.36) with the freehand method versus 2.1 mm (SD ± 0.86) with use of a targeting guide (p = 0.05). The observed difference was more significant (p = 0.03) for more severely retroverted glenoids (> 10°). The mean errors for version and inclination were respectively 4.82° (SD ± 3.12) and 4.2° (SD ± 2.14) with freehand method, compared to 4.87° (SD ± 3.61) and 4.39° (SD ± 3.36) with a targeting guide (p = 0.97 and 0.85, respectively). CONCLUSION: 3D pre-operative planning allowed accurate glenoid component positioning with a freehand method. Compared to the freehand method, patient-specific guides slightly improved the position of the central point, especially for severely retroverted glenoids, but not the orientation of the component.

Quantitative Analysis of Subtalar Joint Motion With 4D CT: Proof of Concept With Cadaveric and Healthy Subject Evaluation.

OBJECTIVE: The purpose of this study was to show the application of quantitative 4D CT for subtalar joint evaluation in healthy volunteers and cadavers. MATERIALS AND METHODS: Fifteen healthy volunteers with no history of subtalar joint trauma and three cadavers were prospectively evaluated with dynamic CT. The subtalar joint was evaluated during a pronosupination cycle. All acquisitions (cadavers and healthy volunteers) were performed using intermittent sequential mode with a 320-MDCT scanner. Angles and distances between the talus and the calcaneus were measured semiautomatically. Measurement variation was described in healthy volunteers and in cadavers, the latter before and after resection of the cervical and interosseous ligaments. The mean effective dose was below 0.1 mSv. RESULTS: In cadavers, mean increases in joint amplitude over 19% and of 22% were seen after partial ligament sectioning and after full ligament sectioning, respectively. The interobserver variability of the measurement ratios was considered to be excellent for three of the measurements made (ICC > 0.87) and moderate for the fourth (ICC = 0.57). The normal range of joint motion in healthy volunteers is described, with joint amplitudes varying from 6.4% to 22.8%. CONCLUSION: Quantitative dynamic CT of the subtalar joint can provide a detailed analysis of joint motion, supporting its potential role in the evaluation of subtalar instability.

Is radiographic measurement of acromiohumeral distance on anteroposterior view after reverse shoulder arthroplasty reliable?

BACKGROUND: Reverse shoulder arthroplasty leads to arm lengthening. Different techniques have been described to determine postoperative lengthening. The purpose of this study was to evaluate the reliability of the acromiohumeral distance (AHD) in determining arm lengthening after reverse shoulder arthroplasty. METHODS: At 2 centers, 44 patients who had received an onlay design reverse shoulder arthroplasty were observed for a minimum of 6 months. Examination followed a standardized protocol including preoperative and postoperative radiographs on anteroposterior view in neutral rotation. Two orthopedic surgeons independently performed the measurements in random order. RESULTS: Mean arm lengthening averaged 2.5 cm (range, 0.3-3.9 cm) according to AHD measurement. Significant differences in interobserver and intraobserver variability for postoperative AHD measurements were found (P < .01). The mean intrapatient difference was 0.5 cm (range, 0.02-1.5 cm). CONCLUSION: According to our study, the AHD is not a reliable measurement technique to determine arm lengthening after reverse shoulder arthroplasty.

Surgical management of the infected reversed shoulder arthroplasty: a French multicenter study of reoperation in 32 patients.

BACKGROUND: In a retrospective multicenter study, we evaluated the efficiency and outcomes of the different therapeutic options for infection after reversed shoulder arthroplasty. METHODS: Thirty-two patients were reoperated on for infection after reversed shoulder arthroplasty between 1996 and 2011. The mean age was 71 (55-83) years. The involved implants were primary prostheses in 23 cases and revision prostheses in 9 cases. The average preoperative Constant score was 34 (11-69). Six of these patients needed 2 successive procedures. A total of 38 procedures were performed: débridement (13), 1-stage (5) or 2-stage revision (14), or implant removal (6). At last follow-up (mean, 36 months; range, 12-137 months), every patient had clinical, biologic, and radiographic evaluation. RESULTS: Infections were largely caused by coagulase-negative staphylococci (56%) and Propionibacterium acnes (59%). The complication rate was 26%. At last follow-up, 26 patients were free of infection (81%). The final Constant score was 46 (12-75). After débridement with implant retention, the mean Constant score was 51 (29-75), but the healing rate was only 54%. Implant revision (1 or 2 stage) led to better functional results than implant removal (46 vs. 25; P = .001), with similar healing rates (73% and 67%, respectively). Patients with low initial impairment (Constant score > 30) were not significantly improved by surgical treatment. CONCLUSION: Débridement is the less aggressive option but exposes patients to healing failure. It should be proposed as a first treatment attempt. Revision of the implant is technically challenging but preserves shoulder function, with no higher rate of residual infection compared with implant removal.

Alginate/sodium caseinate aqueous-core capsules: a pH-responsive matrix.

HYPOTHESIS: Alginate capsules have several applications. Their functionality depends considerably on their permeability, chemical and mechanical stability. Consequently, the creation of composite system by addition of further components is expected to control mechanical and release properties of alginate capsules. EXPERIMENTS: Alginate and alginate-sodium caseinate composite liquid-core capsules were prepared by a simple extrusion. The influence of the preparation pH and sodium caseinate concentration on capsules physico-chemical properties was investigated. FINDINGS: Results showed that sodium caseinate influenced significantly capsules properties. As regards to the membrane mechanical stability, composite capsules prepared at pH below the isoelectric point of sodium caseinate exhibited the highest surface Young's modulus, increasing with protein content, explained by potential electrostatic interactions between sodium caseinate amino-groups and alginate carboxylic group. The kinetic of cochineal red A release changed significantly for composite capsules and showed a pH-responsive release. Sodium caseinate-dye mixture studied by absorbance and fluorescence spectroscopy confirmed complex formation at pH 2 by electrostatic interactions between sodium caseinate tryptophan residues and cochineal red sulfonate-groups. Consequently, the release mechanism was explained by membrane adsorption process. This global approach is useful to control release mechanism from macro and micro-capsules by incorporating guest molecules which can interact with the entrapped molecule under specific conditions.

Morphological and physical analysis of natural phospholipids-based biomembranes.

BACKGROUND: Liposomes are currently an important part of biological, pharmaceutical, medical and nutritional research, as they are considered to be among the most effective carriers for the introduction of various types of bioactive agents into target cells. SCOPE OF REVIEW: In this work, we study the lipid organization and mechanical properties of biomembranes made of marine and plant phospholipids. Membranes based on phospholipids extracted from rapeseed and salmon are studied in the form of liposome and as supported lipid bilayer. Dioleylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) are used as references to determine the lipid organization of marine and plant phospholipid based membranes. Atomic force microscopy (AFM) imaging and force spectroscopy measurements are performed to investigate the membranes' topography at the micrometer scale and to determine their mechanical properties. MAJOR CONCLUSIONS: The mechanical properties of the membranes are correlated to the fatty acid composition, the morphology, the electrophoretic mobility and the membrane fluidity. Thus, soft and homogeneous mechanical properties are evidenced for salmon phospholipids membrane containing various polyunsaturated fatty acids. Besides, phase segregation in rapeseed membrane and more important mechanical properties were emphasized for this type of membranes by contrast to the marine phospholipids based membranes. GENERAL SIGNIFICANCE: This paper provides new information on the nanomechanical and morphological properties of membrane in form of liposome by AFM. The originality of this work is to characterize the physico-chemical properties of the nanoliposome from the natural sources containing various fatty acids and polar head.