Prognostic factors for the occurrence of post-operative shoulder stiffness after arthroscopic rotator cuff repair: a systematic review.

BACKGROUND: Post-operative shoulder stiffness (POSS) is one of the most frequent complications after arthroscopic rotator cuff repair (ARCR). Factors specifying clinical prediction models for the occurrence of POSS should rely on the literature and expert assessment. Our objective was to map prognostic factors for the occurrence of POSS in patients after an ARCR. METHODS: Longitudinal studies of ARCR reporting prognostic factors for the occurrence of POSS with an endpoint of at least 6 months were included. We systematically searched Embase, Medline, and Scopus for articles published between January 1, 2014 and February 12, 2020 and screened cited and citing literature of eligible records and identified reviews. The risk of bias of included studies and the quality of evidence were assessed using the Quality in Prognosis Studies tool and an adapted Grading of Recommendations, Assessment, Development and Evaluations framework. A database was implemented to report the results of individual studies. The review was registered on PROSPERO (CRD42020199257). RESULTS: Seven cohort studies including 23 257 patients were included after screening 5013 records. POSS prevalence ranged from 0.51 to 8.75% with an endpoint ranging from 6 to 24 months. Due to scarcity of data, no meta-analysis could be performed. Overall risk of bias and quality of evidence was deemed high and low or very low, respectively. Twenty-two potential prognostic factors were identified. Increased age and male sex emerged as protective factors against POSS. Additional factors were reported but do require further analyses to determine their prognostic value. DISCUSSION: Available evidence pointed to male sex and increased age as probable protective factors against POSS after ARCR. To establish a reliable pre-specified set of factors for clinical prediction models, our review results require complementation with an expert's opinion.

High rate of maintaining self-dependence and low complication rate with a new treatment algorithm for proximal humeral fractures in the elderly population.

BACKGROUND: We modified our treatment algorithm for proximal humeral fractures in elderly patients in 2013 to a more conservative approach avoiding locking plates. This study assesses the impact of this change on patient self-dependence. METHODS: We carried out an observational comparative study including both retrospectively and prospectively collected data. For the former, 147 isolated proximal humeral fracture patients older than 65 years were treated between 2011 and 2013 at our hospital and included in a historical group. The revised treatment algorithm was applied in a similar non-concurrent, comparative patient group (n = 160) prospectively enrolled between 2015 and 2017. The primary outcome was any loss of self-dependence, with secondary outcomes including documentation of shoulder functional scores, quality of life, and adverse events. RESULTS: Historical and prospective patients had similar baseline characteristics. Nonoperative treatment was performed in 53 historical patients (36%) and 83 prospective patients (78%). Prospective patients were 1.6 times less likely to lose some level of self-dependence (risk ratio, 0.62; 95% confidence interval, 0.25-1.5; P = .292), and the local adverse event risk dropped from 12.2% to 5.7% (P = .078). Mean shoulder function and quality of life were similar between the 2 groups. CONCLUSION: By applying our revised algorithm, a higher proportion of elderly patients maintained their premorbid level of self-dependence and returned to their previous social environment.

Treatment options for proximal humeral fractures in the older adults and their implication on personal independence.

BACKGROUND: No consensus exists on the optimal treatment of proximal humeral fractures (PHFx). Uncertainty about surgical treatment in the older adults using locking plates (e.g., PHILOS) has emerged, due to a high number of complications. This study aimed to assess the impact of non-operative versus operative treatment of a PHFx on the level of self-dependence in our older population. METHODS: We included patients aged over 65 years with some level of self-dependence, treated at our hospital between 5/2011 and 4/2013 for isolated PHFx of AO subtypes A2, A3, and B1 for which either non-operative or surgical treatment using a PHILOS plate had been applied. The patients were questioned, examined, or interviewed via phone; AO fracture patterns and treatment were documented as well as level of self-dependence, complications, constant score (CSM), subjective shoulder value (SSV), quality of life (EQ-5D), and shoulder pain and disability index (SPADI). RESULTS: Patients with PHFx of AO subtypes A2, A3, or B1 that were either treated non-operative (n = 50) or operative by insertion of the PHILOS plate (n = 63) were included. Operative-treated patients were 3.3 times as likely to lose some level of independence (95% CI 0.39-28, p = 0.271). Shoulder motion, strength, and functional outcomes tended to be lower in operative-treated patients, with adjusted differences of, - 11 CMS points (95% CI - 23 to 2), - 9 SPADI points (95% CI - 18 to 0), and - 6% in SSV (95% CI - 17 to 5). Quality-of-life EQ-5D utility index was similar in both groups (mean - 0.04; 95% CI - 0.18 to 0.10). CONCLUSION: In our study population, non-operatively treated older adults with an AO type A2, A3, B1 fracture of the proximal humerus tended to have a high chance to return to their premorbid level of independence, compared to patients treated with a locking plate. A change in the treatment algorithm for these PHFx may be carefully considered and further investigated in clinical practice.

[Update on Shoulder Arthroplasty]. / Aktueller Stand der Schulterendoprothetik.

Update on Shoulder Arthroplasty Abstract. Shoulder arthroplasty is indicated for treatment of primary osteoarthritis, cuff tear athropathy, complex proximal humerus fractures, and posttraumatic situations. The rotator cuff plays an important role. In case of an intact rotator cuff, anatomical shoulder arthroplasty is preferred. Over the past decades, the number of hemi prostheses has declined in favor of total shoulder arthroplasties. Reverse shoulder arthroplasty is used for severe and irreparable rotator cuff tears, advanced cuff tear athropathy, and increasingly for complex proximal humerus fractures. Reverse shoulder arthroplasties account for almost 80 % of all shoulder prostheses. Modern implants allow conversion from an anatomic to a reverse situation if needed. Improved understanding of the pathology, new implant designs, and preoperative 3D planning have improved the overall outcome.

Functional improvement is sustained following anatomical and reverse shoulder arthroplasty for fracture sequelae: a registry-based analysis.

INTRODUCTION: Shoulder arthroplasty for proximal humerus fracture sequelae is known to provide significant patient improvement, yet this outcome varies with time, prosthesis type, and fracture sequelae. We outline the expected course of postoperative shoulder pain and function in patients with anatomical (ASA) or reverse (RSA) shoulder arthroplasty following different fracture sequelae. MATERIALS AND METHODS: Of 111 consecutive patients from our local shoulder arthroplasty registry, 32 underwent ASA for Boileau type 1 sequelae and 77 RSA patients were identified with Boileau types I, III, and IV. By 5 year post-surgery, there were 72 patients available. All patients underwent standardised ASA or RSA procedures with anatomical (Promos Standard; Lima SMR™; Arthrex Eclipse™; Univers™ II) or reverse prostheses (Promos Reverse®; Lima SMR™ Reverse; Univers Revers™; Aequalis® Reversed). Range of motion, Constant-Murley, Disability of the Arm, Shoulder and Hand (DASH), and Shoulder Pain and Disability Index (SPADI) scores were compared at 6, 12, 24, and 60 months postoperatively. We used generalised linear mixed models or random-effects ordered logistic regression to investigate postoperative changes of outcome parameters from baseline to follow-up time points for each group as well as for group comparisons. RESULTS: Range of motion and clinical scores improved until 24 months postoperatively and did not deteriorate thereafter, except for internal rotation of Boileau type III and IV patients and external rotation of RSA patients with type I and IV sequelae. At all follow-ups, ASA patients with Boileau type I sequelae had significantly better internal and external rotation versus patients with RSA and/or other Boileau types (p < 0.001), while Constant, DASH, and SPADI scores were not significantly different between groups. CONCLUSION: In humeral fracture sequelae, ASA and RSA lead to sustained clinical improvements. Surgeons may primarily consider implantation of ASA in type I sequelae.

Glenosphere size in reverse shoulder arthroplasty: is larger better for external rotation and abduction strength?

BACKGROUND: The role of glenosphere size in reverse shoulder arthroplasty (RSA) may be important in prosthetic stability, joint kinematics, rotator cuff tension and excursion, scapular impingement, humeral lateralization, deltoid wrap, and the occurrence of "notching." This study compared short- and midterm clinical and radiographic outcomes for 2 different glenosphere sizes of a single RSA type with respect to implant positioning, glenoid size, and morphology. METHODS: This retrospective analysis included 68 RSA procedures that were prospectively documented in a local register during a 5-year postoperative period. Two glenosphere diameter sizes of 36 mm (n = 33) and 44 mm (n = 35) were used. Standard radiographs were made preoperatively (ie, baseline) and at 6, 12, 24, and 60 months after surgery. Range of motion, strength, the Constant-Murley score, and the Shoulder Pain and Disability Index were also assessed at all follow-up visits. The effect of glenosphere size on measured outcomes was adjusted for baseline values, patient gender, and humeral head diameter. RESULTS: No significant differences were found in the functional scores between treatment groups at all follow-up assessments. At the 12-month follow-up, patients with a 44-mm glenosphere had greater external rotation in adduction (mean difference, 12°; P = .001) and abduction strength (mean difference, 1.4 kg; P = .026) compared with those with the smaller implant. These differences remained at 60 months. Scapular notching was observed in 38% of all patients, without any relevant difference between the groups. CONCLUSION: An increase in glenosphere diameter leads to a clinically moderate but significant increase in external rotation in adduction and abduction strength at midterm follow-up.

Influence of patient and diagnostic parameters on reported retear rates after arthroscopic rotator cuff repair.

PURPOSE: The purpose of this meta-analysis was to investigate patient and diagnostic parameters influencing the reported rates of recurrent rotator cuff defects after ARCR. METHODS: PubMed, EMBASE, Cochrane Library and Scopus databases were searched for clinical studies on tendon defects after ARCR. Imaging modalities, definitions, detection time points, and other known patient risk factors (patient age, tear severity, grade of fatty infiltration, repair technique) as well as reported defect rates were extracted. A meta-analysis of proportion and meta-regression analysis were used to investigate independent variables influencing reported defect rates. RESULTS: Of 109 articles reviewed, the diagnostic studies used magnetic resonance imaging (MRI) only (n = 56), ultrasound (US) only (n = 28), MRI or computed tomography (CT) arthrography (CTA, n = 14) or a combination of US, MRI and CTA (n = 11) up to 57 months after ARCR. Definitions of tendon defects were highly variable, including those of partial tendon healing with insufficient thickness defined as either an acceptable outcome (n = 72) or a recurrent defect (n = 22). Reported defect rates demonstrated highly significant heterogeneity between studies and groups. Follow-up time and the evaluation of partial tendon healing were independent factors of the defect rate alongside age, tear severity and repair technique. The type of imaging did not significantly alter defect rates. CONCLUSION: A number of specific factors significantly alter the rates of rotator cuff defects reported after ARCR. Standardized protocols in clinical practice are required for consistent diagnosis of recurrent defects after ARCR. LEVEL OF EVIDENCE: IV.

Towards standardised definitions of shoulder arthroplasty complications: a systematic review of terms and definitions.

INTRODUCTION: A transparent, reliable and accurate reporting of complications is essential for an evidence-based evaluation of shoulder arthroplasty (SA). We systematically reviewed the literature for terms and definitions related to negative events associated with SA. MATERIALS AND METHODS: Various biomedical databases were searched for reviews, clinical studies and case reports of complications associated with SA. Any general definition of a complication, classification system, all reported terms related to complications and negative events with their definitions were extracted. Terms were grouped and organised in a hierarchical structure. Definitions of negative events were tabulated and compared. RESULTS: From 1086 initial references published between 2010 and 2014, 495 full-text papers were reviewed. Five reports provided a general definition of the term "surgical complication" and 29 used a classification system of complications. A total of 1399 extracted terms were grouped based on similarities and involved implant or anatomical parts. One hundred and six reports (21.4%) defined at least one negative event for 28 different terms. There were 64 definitions related to humeral or glenoid loosening, and 25 systems documenting periprosthetic radiolucency. Other definitions considered notching, stress shielding, implant failure and tuberosity malposition. CONCLUSIONS: A clear standardised set of SA complication definitions is lacking. Few authors reported complications based on definitions mainly considering radiological criteria without clinical parameters. This review should initiate and support the development of a standardised SA complication core set.

Complications associated with arthroscopic rotator cuff tear repair: definition of a core event set by Delphi consensus process.

BACKGROUND: The literature does not consistently report on complications associated with arthroscopic rotator cuff repair (ARCR). Valid comparison of the occurrence of complications between ARCR interventions requires standardization. This project was implemented to define a core set of negative (untoward) events associated with ARCR along with their terms and definitions, which should be systematically documented and reported in routine care and clinical research. MATERIALS AND METHODS: A Delphi consensus process was applied. An international panel of experienced shoulder surgeons was nominated through professional societies and personal contacts. On the basis of a systematic review of terms and definitions, an organized list of relevant events associated with ARCR was developed and reviewed by panel members. Between each survey, all comments and suggestions were considered to revise the proposed core set, including local event groups along with definitions, specifications, and timing of occurrence. Consensus was defined as at least two-thirds agreement. RESULTS: Three successive online surveys were implemented involving 84 surgeons. Consensus with over 86% agreement was reached for a core list of local events including 3 intraoperative event groups (device, osteochondral, and soft tissue) and 9 postoperative event groups (device, osteochondral, pain, rotator cuff, surgical-site infection, peripheral neurologic, vascular, superficial soft tissue, and deep soft tissue). Experts agreed on a period for documentation of each event or group of events ranging from 3 to 24 months after ARCR. CONCLUSION: A structured core set of local events associated with ARCR has been developed by international consensus. Further evaluation and validation in the context of clinical studies are required.

First 50 Pediatric and Adolescent Elbow Arthroscopies: Analysis of Indications and Complications.

BACKGROUND: Elbow arthroscopy is a challenging, yet extremely productive procedure in orthopaedic sports medicine. The severely confined anatomy of the pediatric and adolescent elbow is particularly prone for perioperative complications. This study focuses on the indications and complications of the first 50 elbow arthroscopies in skeletally immature patients done in a specialized pediatric orthopaedic department. PURPOSE: To review analysis of indications and complications in pediatric and adolescent elbow arthroscopy. We hypothesized that the complication rate in these patients is similar to adults. METHODS: Data on 50 consecutive elbow arthroscopies were prospectively gathered in a dedicated database and retrospectively analyzed for indications and perioperative complications. All procedures were performed by a surgeon trained in orthopaedic sports medicine. RESULTS: A total of 26 boys and 24 girls with a mean age of 13.6±3.3 years at the time of surgery and a minimum follow-up of 1 year were included.Fifty-eight percent were treated for osteochondritis dissecans, 24% for arthrofibrosis, 14% for a congenital disorder, and 4% for a posttraumatic problem other than arthrofibrosis. The complication rate was 8%, including 3 cases of transient neuropraxia and 1 superficial wound infection. There were no major complications such as septic arthritis, vascular injury, or permanent nerve damage. All complications resolved fully with conservative treatment, no revision were required. DISCUSSION: Although osteochondritis dissecans is still the leading reason for such surgery, fractures and posttraumatic conditions are becoming more important. With a rate of 5% to 8% of minor, fully resolving complications such an increase is not a reason for concerns. LEVEL OF EVIDENCE: Level IV-case series.

The influence of rotator cuff tear type and weight bearing on shoulder biomechanics in an ex vivo simulator experiment.

Glenohumeral biomechanics after rotator cuff (RC) tears have not been fully elucidated. This study aimed to investigate the muscle compensatory mechanism in weight-bearing shoulders with RC tears and asses the induced pathomechanics (i.e., glenohumeral translation, joint instability, center of force (CoF), joint reaction force). An experimental, glenohumeral simulator with muscle-mimicking cable system was used to simulate 30° scaption motion. Eight fresh-frozen shoulders were prepared and mounted in the simulator. Specimen-specific scapular anthropometry was used to test six RC tear types, with intact RC serving as the control, and three weight-bearing loads, with the non-weight-bearing condition serving as the control. Glenohumeral translation was calculated using instantaneous helical axis. CoF, muscle forces, and joint reaction forces were measured using force sensors integrated into the simulator. Linear mixed effects models (RC tear type and weight-bearing) with random effects (specimen and sex) were used to assess differences in glenohumeral biomechanics. RC tears did not change the glenohumeral translation (p > 0.05) but shifted the CoF superiorly (p ≤ 0.005). Glenohumeral translation and joint reaction forces increased with increasing weight bearing (p < 0.001). RC and deltoid muscle forces increased with the presence of RC tears (p ≤ 0.046) and increased weight bearing (p ≤ 0.042). The synergistic muscles compensated for the torn RC tendons, and the glenohumeral translation remained comparable to that for the intact RC tendons. However, in RC tears, the more superior CoF was close to where glenoid erosion occurs in RC tear patients with secondary osteoarthritis. These findings underscore the importance of early detection and precise management of RC tears.

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon.

BACKGROUND: Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial. PURPOSE: To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects. RESULTS: From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups. CONCLUSION: Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential.

Effectiveness of bracing in the treatment of nonosseous restriction of elbow mobility: a systematic review and meta-analysis of 13 studies.

BACKGROUND: Restriction of elbow mobility is a very frequent complaint after trauma or surgery. The objective of this study was to assess and compare the effectiveness of dynamic, static, or static-progressive bracing in patients with elbow stiffness of traumatic or postoperative origin and without evidence of ossification. For the purpose of this study, effectiveness was measured as the increase in total range of motion, as well as extension and flexion. MATERIALS AND METHODS: We performed a systematic search of the keywords "elbow AND (stiffness OR stiff) AND (brace OR splint OR conservative)" in the online databases PubMed, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the Cochrane Library. We included all clinical studies using dynamic or static bracing in patients with elbow stiffness. Eligible outcomes were changes in total range of motion, flexion, and extension; sustainability of results; and complications. RESULTS: We included 13 eligible studies, providing data on 14 treated groups in 247 patients. The mean age of these patients was 34.5 ± 10.4 years, and female patients comprised 46% ± 12%. The mean duration from the incident to the start of brace treatment was 6.9 ± 5.1 months. The mean improvement in range of motion during the course of treatment was 38.4° ± 8.9° (95% confidence interval, 39.5°-41.8°). CONCLUSIONS: The current evidence strongly supports the use of static-progressive stretching 3 times 30 minutes per day in each direction as a first line of treatment in patients with post-traumatic and postsurgical elbow stiffness. If this treatment fails or if reasons for stiffness other than soft-tissue incompliance are identified, further surgical interventions should be considered.

Current Understanding and New Advances in the Surgical Management of Reparable Rotator Cuff Tears: A Scoping Review.

Rotator cuff (RC) tears are among the most common musculoskeletal disorders and can be associated with pain, weakness, and shoulder dysfunction. In recent years, there have been significant advances with regard to the understanding of rotator cuff disease and its management. With technological improvements and advanced diagnostic modalities, there has been much progress as to improved understanding of the pathology. Similarly, with advanced implant designs and instrumentation, operative techniques have evolved. Furthermore, refinements in postoperative rehabilitation protocols have improved patient outcomes. In this scoping review, we aim to provide an overview of the current knowledge on the treatment of rotator cuff disorders and to highlight recent advances in its management.

Conservative treatment of Rockwood type III acromioclavicular joint separation: a randomized controlled trial sling vs. brace.

Background: Management of Rockwood III acromioclavicular joint separations is a matter of ongoing debate, with nonoperative treatment being favored in recent literature. The aim of this study is to compare clinical and radiological outcomes of nonoperative treatment with a brace, which elicits a direct reduction force to the distal clavicle, to a sling. We hypothesized the brace might yield in better acromioclavicular joint (ACJ) reduction and cosmesis. Methods: In this dual center prospective randomized controlled trial, all patients sustaining an acromioclavicular joint separation Rockwood III between July 2017 and August 2020 were included. Patients with previous ipsi- or contralateral ACJ injury or surgery were excluded. Randomization occurred in the emergency department to either the sling or brace group. Patients were followed up at 1, 6, and 12 weeks. Patient-reported outcome measures included subjective shoulder value (SSV) and American Shoulder and Elbow Surgeons (ASES) score at each follow-up and Constant Score at 6 and 12 weeks. Vertical distal clavicle displacement was assessed on bilateral non-weighted panoramic anteroposterior radiographs using coracoclavicular (CC) distance to calculate the CC-index. Results: Thirty-five consecutive patients were included across the 2 sites, 18 (all male) in the brace and 17 (14 male) in the sling group. Baseline characteristics did not differ significantly between groups, the average age was 40 years, and body mass index 25.5 kg/m2. Analysis revealed no statistical difference in CC-index between groups at the time of injury, 6 weeks and 12 weeks postinjury (P = .39, P = .11, and P = .21). SSV improved from 30 and 35 postinjury to 81 and 84 at 12 weeks in the sling and brace group, respectively (P = .59). ASES improved from 48 and 38 to 82 and 83, respectively (P = .84). Similarly, Constant Score improved from 64 and 67 to 82 and 81, respectively (P = .90). One patient in the brace group underwent ACJ stabilization with hamstring autograft at 4 months due to persistent pain. Conclusion: This randomized controlled trial shows no statistically significant difference between the brace and sling group in clinical (SSV, ASES, Constant Score) or radiological (CC-index) outcomes after conservative treatment of Rockwood III injuries.

Ex vivo experimental strategies for assessing unconstrained shoulder biomechanics: A scoping review.

BACKGROUND: Biomechanical studies of the shoulder often choose an ex vivo approach, especially when investigating the active and passive contribution of individual muscles. Although various simulators of the glenohumeral joint and its muscles have been developed, to date a testing standard has not been established. The objective of this scoping review was to present an overview of methodological and experimental studies describing ex vivo simulators that assess unconstrained, muscular driven shoulder biomechanics. METHODS: All studies with ex vivo or mechanical simulation experiments using an unconstrained glenohumeral joint simulator and active components mimicking the muscles were included in this scoping review. Static experiments and humeral motion imposed through an external guide, e.g., a robotic device, were excluded. RESULTS: Nine different glenohumeral simulators were identified in 51 studies after the screening process. We identified four control strategies characterized by: (a) using a primary loader to determine the secondary loaders with constant force ratios; (b) using variable muscle force ratios according to electromyography; (c) calibrating the muscle path profile and control each motor according to this profile; or (d) using muscle optimization. CONCLUSION: The simulators with the control strategy (b) (n = 1) or (d) (n = 2) appear most promising due to its capability to mimic physiological muscle loads.

Intraoperative engineering of osteogenic grafts combining freshly harvested, human adipose-derived cells and physiological doses of bone morphogenetic protein-2.

Engineered osteogenic constructs for bone repair typically involve complex and costly processes for cell expansion. Adipose tissue includes mesenchymal precursors in large amounts, in principle allowing for an intraoperative production of osteogenic grafts and their immediate implantation. However, stromal vascular fraction (SVF) cells from adipose tissue were reported to require a molecular trigger to differentiate into functional osteoblasts. The present study tested whether physiological doses of recombinant human BMP-2 (rhBMP-2) could induce freshly harvested human SVF cells to generate ectopic bone tissue. Enzymatically dissociated SVF cells from 7 healthy donors (1 x 10(6) or 4 x 10(6)) were immediately embedded in a fibrin gel with or without 250 ng rhBMP-2, mixed with porous silicated calcium-phosphate granules (Actifuse(®), Apatech) (final construct size: 0.1 cm(3)) and implanted ectopically for eight weeks in nude mice. In the presence of rhBMP-2, SVF cells not only supported but directly contributed to the formation of bone ossicles, which were not observed in control cell-free, rhBMP-2 loaded implants. In vitro analysis indicated that rhBMP-2 did not involve an increase in the percentage of SVF cells recruited to the osteogenic lineage, but rather induced a stimulation of the osteoblastic differentiation of the committed progenitors. These findings confirm the feasibility of generating fully osteogenic grafts using an easily accessible autologous cell source and low amounts of rhBMP-2, in a timing compatible with an intraoperative schedule. The study warrants further investigation at an orthotopic site of implantation, where the delivery of rhBMP-2 could be bypassed thanks to the properties of the local milieu.

Ex-vivo experimental strategies for assessing unconstrained shoulder biomechanics: a scoping review protocol.

Background: Shoulder biomechanics cannot be measured directly in living persons. While different glenohumeral joint simulators have been developed to investigate the role of the glenohumeral muscles in shoulder biomechanics, a standard for these simulators has not been defined. With this scoping review we want to describe available ex-vivo experimental strategies for assessing unconstrained shoulder biomechanics. Objective: The scoping review aims at identifying methodological and/or experimental studies describing or involving ex-vivo simulators that assess unconstrained shoulder biomechanics and synthesizing their strengths and limitations. Inclusion criteria: All unconstrained glenohumeral joint simulators published in connection with ex-vivo or mechanical simulation experiments will be included. Studies on glenohumeral simulators with active components to mimic the muscles will be included. We will exclude studies where the experiment is static or the motion is induced through an external guide, e.g., a robotic device. Methods: We will perform database searching in PubMed, Embase via Elsevier and Web of Science. Two reviewers will independently assess full texts of selected abstracts. Direct backward and forward citation tracking on included articles will be conducted. We will narratively synthesize the results and derive recommendations for designing ex-vivo simulators for assessing unconstrained shoulder biomechanics.

Fluoroscopy of the Elbow: A Cadaveric Study Defining New Standard Projections to Visualize Important Anatomical Landmarks.

BACKGROUND: Despite new 3-dimensional imaging modalities, 2-dimensional fluoroscopy remains the standard intraoperative imaging modality. The elbow has complex anatomy, and defined standard fluoroscopic projections are lacking. Therefore, the aim of this study was to define standard projections of the elbow for intraoperative fluoroscopy. METHODS: This study consisted of 2 parts. In part I, dissected cadaveric elbows were examined under fluoroscopy, and their radiographic anatomical features were assessed, with focus on projections showing defined anatomical landmarks. In part II, projections from part I were verified on entire cadavers to simulate intraoperative imaging. Standard projections for anteroposterior (AP) and lateral views as well as oblique and axial views were recorded. RESULTS: Eight standardized projections could be defined and included 3 AP, 1 lateral, 2 oblique, and 2 axial views. By applying these specific projections, we could visualize the epicondyles, the trochlea with its medial and lateral borders, the capitellum, the olecranon, the greater sigmoid notch, the coronoid process including its anteromedial facet, the proximal radioulnar joint with the radial tuberosity, and the anterior and posterior joint lines of the distal part of the humerus. These standard projections were reliably obtained using a specific sequence. CONCLUSIONS: Knowledge about radiographic anatomy and standard projections is essential for visualizing important landmarks. With the presented standard projections of the elbow, important anatomical landmarks can be clearly examined. Thus, fluoroscopic visualization of anatomical fracture reduction and correct implant placement should be facilitated. CLINICAL RELEVANCE: This basic science cadaveric study defines fluoroscopic standard projections of the elbow essential for visualization of anatomical landmarks during surgery.

Prediction of Shoulder Stiffness After Arthroscopic Rotator Cuff Repair.

BACKGROUND: Postoperative shoulder stiffness (POSS) is a prevalent adverse event after arthroscopic rotator cuff repair (ARCR) that is associated with major limitations in everyday activities and prolonged rehabilitation. PURPOSE/HYPOTHESIS: The purpose was to develop a predictive model for determining the risk of POSS within 6 months after primary ARCR. We hypothesized that sufficient discrimination ability of such a model could be achieved using a local institutional database. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Consecutive primary ARCRs documented in a local clinical registry between 2013 and 2017 were included, and patients who experienced POSS before the final clinical 6-month follow-up were identified. A total of 29 prognostic factor candidates were considered, including patient-related factors (n = 7), disease-related factors (n = 9), rotator cuff integrity factors (n = 6), and operative details (n = 7). We used imputed data for the primary analysis, and a sensitivity analysis was conducted using complete case data. Logistic regression was applied to develop a model based on clinical relevance and statistical criteria. To avoid overfitting in the multivariable model, highly correlated predictors were not included together in any model. A final prognostic model with a maximum of 8 prognostic factors was considered. The model's predictive accuracy was assessed by the area under the receiver operating characteristic curve (AUC). Internal validation was performed using bootstrapping. RESULTS: Of 1330 ARCR cases (N = 1330 patients), 112 (8.4%) patients had POSS. Our final model had a moderate predictive ability with an AUC of 0.67. The predicted risks of POSS ranged from 2.3% to 38.9% and were significantly higher in women; patients with partial tears, low baseline passive shoulder abduction, and lack of tendon degeneration; and when no acromioplasty was performed. CONCLUSION: A prognostic model for POSS was developed for patients with ARCR, offering a personalized risk evaluation to support the future decision process for surgery and rehabilitation.