Glenoid Research Articles

A Full Digital Workflow to Design and Mill a Splint for a Patient with Temporomandibular Joint Disorder

In the rehabilitation of a patient with loss of vertical dimension, repositioning of the condyle may be crucial to avoid loading on the retrodiscal area of the temporomandibular joint (TMJ). However, establishing a new position of the condyle within the glenoid cavity is not a simple procedure, and several indications exist in the literature. Digital techniques and 3D visualization using cone beam computed tomography (CBCT) can help. In this clinical case, the procedure for the repositioning of the condyle is described on the basis of the restoration of the normal widths of the intra-articular spaces using a recently introduced software (Avantis3D). After the end of the rehabilitation with the splint, a second examination confirmed the accuracy of the repositioning with this full digital procedure which represents, in selected cases, a useful choice.

WITHDRAWN: Morphometric Analysis of Cavitas Glenoidalis with Multidedector CT.

Ahead of Print article withdrawn by publisher.

Scapular Glenoid Cavity in Central Indian Population: A Morphological Study

Introduction: The Glenoid Cavity (GC) of scapula has highly variable morphology. The rim of GC presents a notch in its upper and front part, because of this glenoid notch, various shapes of GC are found like pear, oval or inverted comma shaped. For total shoulder arthroplasty, knowledge of the shape and dimensions of the glenoid are important in the design and fitting of glenoid component. Various anatomical parameters of the glenoid like height, width, articular surface area, inclination, vault size and shape are relevant for prosthesis design. There is considerable natural variability in these parameters. Anatomical variations of GC are also important for understanding the various pathologies involving the shoulder joints. The present study tries to determine the measurements of various dimensions of the GC including the variations in its shape and surface area. Aim: To obtain the morphometric data and various shapes of the GC relevant to the central Indian population and to compare the data obtained from the present study with previous studies. Materials and Methods: The study was carried out on 150 dry, adult human scapulae of unknown sex, collected from the museum of Department of Anatomy, out of which, 67 were of right side and 83 of left side belonging to central Indian population of unknown sex and age. Morphological evaluation and morphometric measurements for GC were done in each scapula using digital vernier calliper. The height and anteroposterior diameter of the GC was measured at three different levels. Shape of the GC, based on the presence of a notch on the anterior glenoid rim, was noted as pear, oval or inverted comma shape. Results: The mean Superior-inferior (SI) diameter of the GC was observed as 33.84±3.08 mm on right side and 33.68±2.75 mm on left side. The mean Anterior Posterior 1 was 23.65±3.47 and 23.60±2.79 on right and left side, respectively. Anterior Posterior 2 was 14.98±2.41 and 14.16±2.23 on right and left side, respectively, whereas, Anterior Posterior 3 were 19.12±3.59 and 18.44±3.11 on right and left side, respectively. A 33.3% glenoid cavities were oval shaped, 50.66% were of pear shape and 16% were of inverted comma shape. Conclusion: The present study can be helpful to orthopaedic surgeons and biomechanical engineers during designing and fitting the implants for total shoulder arthroplasty. The size of the GC is known to be variable in different population. Hence, while designing the glenoid component of the prosthesis; smaller dimensions of the glenoid cavities in Indian population should be considered.

Surgical Reduction of Symphysis Fracture and Spontaneous Repositioning of the Mandibular Condyle: A Case Report

The condylar process is a more fragile area, which is usually fractured by indirect trauma. The objective of this study is to report the case of a 10-year-old patient who presented to the Maxillofacial Surgery and Traumatology Service of the Regional Hospital of Vale do Paraíba, in Taubaté-SP, Brazil. Physical examination revealed limited mandibular movement with painful symptoms, crossbite, and upper incisor avulsion. A face tomography showed a fracture of the mandibular symphysis (right side) and a fracture of the left condyle. Surgical reduction of the mandibular symphysis fracture was performed. After exposure and reduction of bone segments, maxillomandibular block, rigid internal fixation and conservative treatment for condyle fracture were performed. A soft liquid diet and weekly outpatient follow-up was adopted for the first two months. After 15 days of surgery, the patient had mild edema, slight limitation in mouth opening, sutures without dehiscence and without signs of infection. In the first control tomography, the treated fracture was adequately reduced and the fractured condyle remained with medial displacement in the glenoid cavity. After one year, on physical examination, the patient presented satisfactory dental occlusion, preserved mandibular movements and no signs of nerve damage. The tomography showed the fracture consolidated, and the left mandibular condyle well positioned in the glenoid cavity. After two years, the third tomography was performed, showing remodelling of the left mandibular condyle.

Sexual dimorphism of the scapula by morphometric analysis in south Indian population

Background: Forensic anthropology plays a key role in sexual dimorphism. It is possible to establish a profile and identification of the sex of an individual from the available parts of the skeleton. Several bones present dimorphism and have been studied to increase the approach for forensic identification. Objective: We morphometrically evaluated the human scapula and compared the measurements between scapula bone in cadavers of both sex to derive a logistical regression formula for sex determination of the south Indian population. Materials and Methods: Eighty adult scapulae were used in the study. Scapulae were measured in millimeters for 11 parameters with the help of the sliding caliper. Results: The most common shape of glenoid cavity recorded in this study in men and women was pear shape (54.92% and 51.02%) followed by inverted comma shape (31. 49% and 33.73%). The least common shape was oval (13.57% and 15.28). The mean (standard deviation [SD]) of parameters studies in men vs. women: MSH––143.3 ± 10.23 vs. 138.2 ± 11.89 mm; the MSB––105.3 ± 12.45 vs. 93.5 ± 9.23 mm; SpW––120.0 ± 0.81 vs. 104.0 ± 0.95 mm; ACW––87.0 ± 0.58 vs. 80.0 ± 0.53 mm; L2––44.7 ± 0.46 vs. 35.3 ± 0.39 mm; L4–50.5 ± 8.6 vs. 45.3 ± 9.51; L6–60.1 ± 7.71 vs. 56.8 ± 8.55 mm; SI glenoid diameter––37.63 ± 7.58 vs. 35.5 ± 4.75 mm; the anteroposterior glenoid diameter 1––24.50 ± 5.86 vs. 22.5 ± 6.93 mm and the anteroposterior glenoid diameter 2––16.30 ± 2.16 vs. 13.57 ± 5.58 mm; and mean glenoid cavity index was 65.10 ± 8.67% vs. 63.4 ± 9.23%. All parameters measured showed statistically significant values (P < 0.05) for the male scapula. Conclusion: The scapula can potentially be used in medicolegal investigations in terms of sexual dimorphism. Thus, the results of these studies can provide the baseline values increasing the range of options in the forensic investigation in sex determination.

Morphological Variation of Suprascapular Notch in Population of Eastern India and its Clinical Significance

Introduction: Suprascapular notch is present at the lateral part of the superior border of scapula which is bridged by superior transverse scapular ligament. The suprascapular nerve runs below the ligament and the transverse scapular vessels over it. The ligament sometimes becomes ossified and impinges the underlying nerve which causes paralysis of both supraspinatus and infraspinatus muscles. Aim: To study the morphological variation of suprascapular notches in dry human scapulae. Materials and Methods: This observational cross-sectional study was carried out on 102 adult dry human scapulae (62 right, 40 left) collected from the 1st year MBBS students of different Medical colleges of West Bengal from August 2020 to March 2021. The shapes of suprascapular notch, presence of ossified ligaments were observed. Superior Transverse Diameter (STD), Middle Transverse Diameter (MTD), Maximum Depth (MD) of the suprascapular notch, distance from the deepest point of suprascapular notch to supraglenoid tubercle and distance between the spinoglenoid notch to the posterior rim of glenoid cavity were measured and statistically analysed. Classification of the suprascapular notch was done based on Rengachary classification. Results: Type III notch was most common (n=52). One scapula had small U-shaped notch with lateral part of the ligament ossified and another had U-shaped notch with both medial and lateral part of the ligament ossified but they failed to join. In Type I and Type VI there were no such diameters like STD or MTD but for other types STD was more than MTD. The distance between suprascapular notch and supraglenoid tubercle was variable- type VI had minimum and type I had the maximum distance. The distance between the medial wall of the spinoglenoid notch and the posterior rim of glenoid cavity was least in type I and highest in type III. Conclusion: This study showed that type III was the most common suprascapular notch. The present study also compared the findings with other previous studies and found that percentage of presence of suprascapular foramen in this eastern Indian population was higher than southern Indian population.

Arthroscopic repair of acute bony Bankart lesions: An analysis of risk factors for instability recurrence

Purpose. To determine clinical and radiological outcomes of patients with acute bony Bankart lesions treated via the arthroscopic approach and evaluate the hypothesis that instability recurrence is associated with fragment reduction quality and/or glenoid defect. Material and Methods . Between 2008 to 2013, 27 patients (mean age 24.3 years) were examined before, and (on average) 29 months after, arthroscopic repair. Inclusion criteria were acute bony Bankart lesions, glenoid osseous defects of less than 20%, and postoperative follow-up period of at least 24 months. Functional recovery was assessed using the Rowe, Western Ontario Shoulder Instability Index (WOSI), and UCLA shoulder rating scales. Computed tomography scans were used to evaluate reduction and healing of bony fragments. Cases of instability recurrence were documented. Results. Postoperative mean Rowe score was 90.4 points (range, 35 to 100 points), the mean WOSI was 282.0 (range, 25-1100 points), and the mean UCLA was 28.5 points (range, 15 to 35 points). The recurrence rate of shoulder instability was 7.4% (2/27), which only occurred in cases of fragment malposition. The average loss of external rotation was 5o at 0o of abduction, and 7o at 90o of abduction. Twenty three patients (85.19%) returned to preinjury sport level. Radiological assessment revealed complete union of the bony fragment in all cases. Conclusion . Arthroscopic reduction and suture anchor fixation of acute bony Bankart lesions yield excellent outcomes providing a low recurrence instability and high bone union rates. In addition, non-anatomical reduction of the bony fragment is a reliable risk factor for instability recurrence in acute cases.

Surgical Anatomy of the Glenoid Cavity and Its Use in Shoulder Arthroplasty Among the North Indian Population.

Background and objectiveThe head of the humerus articulates with the glenoid cavity (GC) to form the shoulder joint. Understanding the various shapes and sizes of GC is important not only to analyse the stability of the glenohumeral joint but also to design prostheses for shoulder arthroplasty. Morphometric data on GC among the North Indian population is scarce. Hence, the aim of this study was to provide morphological and morphometric data on GC among the North Indian population.MethodsThis study was conducted in the department of anatomy of two medical colleges using undamaged dry scapulae. The shapes of GC and supero-inferior (SI) and maximum anteroposterior diameters above and below the notch were recorded. Statistical analysis and Student's t-test were carried out to identify statistically significant differences in diameters of the two sides of GC.ResultsThe most common and least common shapes of GC were pear and inverted comma shapes respectively. The mean SI glenoid diameter was 33.6 ± 3.2 mm. The mean of H1 and H2 diameter was 23.6 ± 3.1 and 15.3 ± 2.1 mm respectively. The mean GC indices on the right and left sides were 72.16 and 68.14 respectively. In all of the above measurements, bilateral differences were not statistically significant (p-values of ˃0.05).ConclusionsThe morphometric data on GC may be used to design prostheses for shoulder arthroplasty among the North Indian population. The information is also useful in detecting various pathological conditions of the shoulder like rotator cuff disease, osteochondral defects, and Bankart lesions.

Association between superior semicircular canal dehiscence and other dehiscences in temporal bone.

The study of the association between superior semicircular canal and other dehiscences in the temporal bone. We have studied computed tomography of radiologically diagnosed people with superior or posterior semicircular canal dehiscences, in four health centres. In addition, we have studied one isolated human temporal bone, one skull and one cadaver head belonging to the collection of the Department of Human Anatomy and Histology of the University of Zaragoza that had dehiscence in the superior semicircular canal. The most frequent association that we observed was between superior semicircular canal dehiscence and tegmen tympani dehiscence (37.33%). Three cases (two clinical cases and one isolated temporal bone) showed multiple associated dehiscences (tegmen tympani, mastoid antrum, posterior semicircular canal, internal auditory canal, glenoid cavity, tympanum bone and geniculate ganglion) associated with superior semicircular canal dehiscence. When the superior semicircular canal dehiscence is associated to other in the petrous bone (tegmen tympani, mastoid antrum, posterior semicircular canal, internal auditory canal) could be grouped into the same syndrome called "otic capsule syndrome", since they have the same origin and common aetiology (otic capsule).

La forme de la cavité glénoïdale de la scapula humaine: variabilité et hypothèse fonctionnelle

The glenoid cavity of the scapula can be sorted according to its shape in lateral view: pear-shaped cavities are more frequent than egg-shaped ones, elliptic shapes being the rarest. The morphology of the glenoid cavities is usually the same on both sides of a given individual, but when asymmetrical, pear-shaped cavities are more often present on the right, the other shapes being more frequent on the left. Elliptic and egg-shaped cavities are more common in men than in women. Elliptic glenoid cavities and the associated humeral heads are usually of big size, suggesting that they could be well adapted to sustain significant loads. No other functional particularity stood out from the analysis of the shape of the glenoid fossa. By contrast, egg-shaped and mainly elliptic types much more frequently show a remodelled border. This suggests that those shapes could be the result of a secondary deformation of the pear-shaped type under the action of loads applied on the scapulohumeral joint. Either their intensity or their direction would determine the shape acquired by the glenoid cavity at the time of death.

Applied anatomical study on suprascapular nerve protection in reverse total shoulder arthroplasty

BackgroundThis study aimed to investigate the three-dimensional (3D) anatomical relationship between the suprascapular nerve and scapula, and the method of protecting the suprascapular nerve in reverse total shoulder arthroplasty (RTSA)MethodsIn the present study, 12 fresh adult cadaver shoulder specimens were dissected. X-ray and computed tomography (CT) were used to investigate the 3D scapular and suprascapular nerve images.ResultsThe results revealed that the best fitting baseplate diameter was 24.73 ± 1.56 mm. Furthermore, the baseplate diameter correlated with the glenoid cavity width. After the osteotomy, a simulated screw placement on the baseplate was performed. The dangerous area for the posterior screw placement was at the angle between the upper edge and transverse axis exceeding 38° and between the lower edge and transverse axis exceeding 76°. The distance between the nearest point of the nerve and osteotomy plane was 15.38 ± 2.02 mm, and the angle between the projection point of the nearest point and transverse axis was 27.33 ± 7.96°, which was the dangerous area for retractor placement. The suitable angle between the superior screw and longitudinal axis was 21.67 ± 13.27°, and the suitable superior screw length was 34.66 ± 2.41 mm.ConclusionIn RTSA, the baseplate size correlates with the glenoid cavity width. The relationship between the screw and suprascapular nerve and retractor placement position should be carefully considered to avoid damaging the suprascapular nerve.

A gender-based comparison of coracoid and glenoid anatomy: CT analysis and discussion of potential impact on the Latarjet procedure

The success of the modified Latarjet procedure depends on proper sizing of the coracoid graft. There is no information available regarding the morphometric relationship between the glenoid cavity and the coracoid process for the South African population. This study aims at measuring the relationship between the glenoid and coracoid morphometries and investigates their gender-related differences. Glenohumeral computerized tomography scans of 100 consecutive patients were considered for this study. Morphometric measurements were performed after aligning the coracoid and glenoid in their optimum orientation. These measurements were performed by 2 independent observers. The ratio between glenoid and coracoid measurements was calculated and statistically compared using the Mann-Whitney U test. Intraclass correlation coefficients were calculated to analyze interobserver reliability. All the statistical tests were performed in SPSS v.26, and power calculations in G∗Power v.3.1. An average intraclass correlation coefficient value of 0.79 suggested that the interobserver reliability was good. Except for coracoid length, statistically significant (P < .05) gender differences were observed for all the other morphometries. The coracoid width (16.5 ± 1.4 mm vs. 14.7 ± 1.4 mm) and height (13.6 ± 1.6 mm vs. 10.5 ± 1.5 mm) differed between genders by 1.8 and 3.1 mm, respectively. The glenoid anteroposterior (AP) (25.3 ± 2.9 mm vs. 23.2 ± 2.4 mm) and superioinferior (36.9 ± 1.9 mm vs. 33.7 ± 2.6 mm) measurements differed by 2.1 and 3.3 mm, respectively, between the males and the females. The ratio between the AP width of the glenoid and the coracoid height was also found to be significantly different (P < .05) between the gender groups. These morphometric ratios for the coracoid width (0.66 ± 0.09 mm vs. 0.64 ± 0.08 mm) and the coracoid height (0.55 ± 0.09 mm vs. 0.46 ± 0.07 mm) differed between genders by 0.02 and 0.09, respectively. Measurements taken from computerized tomography scans showed significant differences between genders in absolute measurements and in the ratio of the coracoid height to the glenoid AP distance. This could have implications on the ability of the Latarjet procedure to compensate for bone loss in female patients.

COMPARISON OF FUNCTIONAL OUTCOME OF SURGICAL TREATMENT OF RECURRENT ANTERIOR SHOULDER DISLOCATION

Abstract&#x0D; Background &#x0D; Shoulder joint is the most mobile joint of the body. Shoulder joint dislocation accounts for the 50% of all the dislocations. Its incidence is 2 % among general population. In most of the cases it is recurrent shoulder dislocation and in 97% cases of recurrent dislocation it is anterior dislocation. Mechanism for recurrent anterior dislocation is abduction, external rotation and extension. There is persistent inability of tissues to keep the humeral head in glenoid cavity. It may result from sudden injury to glenoid cavity (Bankart lesion), proximal humerus (Hillsachs lesion), repetitive micro trauma or and a result of generalized ligamentous laxity. Once the shoulder is dislocated it is vulnerable to repetitive episodes.&#x0D; Objective:&#x0D; To compare the functional outcome of two different treatment modalities (latarjet &amp;Bristow procedure and Bankart Repair) in recurrent anterior shoulder dislocation&#x0D; Subjects and methods &#x0D; Study design: randomized clinical trial&#x0D; Settings and duration: department of orthopaedic surgery services hospital Lahore from December 2017 to December 2018.&#x0D; Sample collection: A total no of 40 patients with age 18-30 years both male and female having recurrent anterior dislocation of shoulder were included in the study. Patients with ligamentous laxity, psychological ailment and global instability were excluded from the study.&#x0D; Data collection and analysis: Patients were divided in two groups having 20 patients in each group. Detailed history, clinical examination, radiographs, CT scan and MRI was completed to establish the diagnosis of recurrent anterior shoulder dislocation. We performed Bristow latarjet procedure in group a and Bankart repair in group B. All patients were followed at 1st , 2nd , 3rd , 4th,6th week and then at 4th , 6th and 9 months clinically and radiologically to assess the Instability and mobility by using Rowe score.&#x0D; Results: there were 16 males and 4 females while in group B were 17 males and 3 females. Mean age in group A was 26.7 years (18-30) while in group B was 27 years (18-29) which was statistically insignificant (p&gt;0.05). Right shoulder was involved in 13 (65%) patients in group A and 15 (75%) in group B. left shoulder was involved in 7 (35%) patients of Group A and 5 (25%) of group B. In group A 18 patients had excellent results, one patient was having grade I subluxation and one patient had positive apprehension test. In group B four patients had recurrence and three patients had subluxation of grade II.&#x0D; Conclusion&#x0D; Results of latarjet and Bristow procedure were excellent than Banckart repair. Patients satisfaction was also better in group A than group B.&#x0D; &#x0D;

Diagnostic needle arthroscopy of the scapulohumeral joint in standing sedated horses.

To describe the technique to perform diagnostic standing scapulohumeral joint needle arthroscopy with a 1.2-mm-diameter arthroscope in horses. Experimental study. Eight thoracic limbs in phase 1 and six horses in phase 2. In phase 1, the feasibility of the technique was evaluated by using a craniolateral arthroscopic approach. An evaluation of the visible structures of the scapulohumeral joint was performed with both a needle arthroscope and a 4-mm-diameter arthroscope. In phase 2, the technique was performed in six healthy sedated horses to validate the technique in live animals and to report any complications or limitations. In phase 1, joint evaluation was similar between arthroscopes and allowed complete evaluation of approximately the lateral half of the humeral head and the lateral glenoid rim. In phase 2, all joints were successfully accessed, and fluid extravasation was mild. Arthroscopic visualization was complete for the centrolateral aspect of the joint in all horses and either complete (3/6) or partial (3/6) for the craniolateral and caudolateral structures, respectively. The procedure was rapidly performed and well tolerated, and no postoperative complications occurred. The described technique was simple and allowed direct inspection of the scapulohumeral joint. Nonetheless, the standing nature of the technique prevents evaluation of the medial aspect of the humeral head and most of the glenoid cavity. Needle arthroscopy of the scapulohumeral joint is feasible in horses and offers a diagnostic technique that may improve the surgeon's diagnostic ability for certain shoulder pathologies.

Geographic variations of skull morphology in the Rhinolophus ferrumequinum species complex (Mammalia: Chiroptera)

The greater horseshoe bat (Rhinolophus ferrumequinum), distributed from Europe and Northeast Africa through the temperate regions of Asia to Japan, is regarded as either a single, albeit polytypic, species or as representing a complex of two species, R. ferrumequinum sensu stricto in the western part and R. nippon in the eastern part of the seemingly continuous range. To evaluate patterns of geographic variation within the complex and to determine if distinguishing morphological characters exist between R. ferrumequinum and R. nippon, we performed a comprehensive comparative study of skull morphology, combining traditional linear measurements, geometric morphometric methods, and evaluation of non-quantitative discriminant characters. We analyzed 230 specimens from 19 localities in 10 geographic regions sampled from central Europe, Iraq, Nepal, China, North Korea, South Korea, and Japan. Our results revealed remarkable differences in skull morphology between the European-West Asian and East Asian groups; variation between these two groups was considerably larger than within-group variation. The two groups were separable by three main features: 1) the position of the anterior palatal edge in relation to the cusps of the upper first molar; 2) the position of the glenoid cavity; and 3) the robustness of the skull as expressed by the ratio of the zygomatic and mastoid widths. In line with recent molecular biological studies, we recommend recognizing R. ferrumequinum (Schreber, 1774) and R. nippon Temminck, 1835 as two distinct species. Our results also revealed unique size variations in island populations of R. nippon, presumably shaped by the island rule and the founder effect.

English

English

DOUBLE CONTOUR SIGN IN TEMPOROMANDIBULAR JOINTS IN CONE BEAM COMPUTED TOMOGRAPHY: A CASE SERIES.

Clinical Presentation A double contour of the cortical border in the temporomandibular joints (TMJs) is a rare sign that can be seen in the mandibular condyles and/or in the glenoid cavity. This sign can be attributed to several causes and may have different clinical manifestations and management. Differential Diagnosis Subcortical erosion, incipient formation of subchondral cysts, and crescent sign were considered. Movement artifacts may sometimes create a false-positive sign. Diagnosis and Management Double contour of the TMJs can be better visualized on cone beam computed tomography. Because it is a nonspecific sign, it must be correlated with a complete medical history to be linked to a specific diagnosis. Discussion Double contour of the components of the TMJs can represent a sign of active pathosis and be a sign of bone remodeling in asymptomatic patients. Magnetic resonance imaging and clinical studies have shown a strong correlation between double contour and disk dislocation. It is important that the radiologist identify this sign and its clinical significance, with the purpose of helping the clinician in diagnosis and management. A double contour of the cortical border in the temporomandibular joints (TMJs) is a rare sign that can be seen in the mandibular condyles and/or in the glenoid cavity. This sign can be attributed to several causes and may have different clinical manifestations and management. Subcortical erosion, incipient formation of subchondral cysts, and crescent sign were considered. Movement artifacts may sometimes create a false-positive sign. Double contour of the TMJs can be better visualized on cone beam computed tomography. Because it is a nonspecific sign, it must be correlated with a complete medical history to be linked to a specific diagnosis. Double contour of the components of the TMJs can represent a sign of active pathosis and be a sign of bone remodeling in asymptomatic patients. Magnetic resonance imaging and clinical studies have shown a strong correlation between double contour and disk dislocation. It is important that the radiologist identify this sign and its clinical significance, with the purpose of helping the clinician in diagnosis and management.

Development and Preclinical Trials of a Novel Steerable Cannula for 360° Arthroscopic Capsular Release in Minimally Invasive Surgery.

Many of the surgical devices for minimally invasive surgery have struggled to navigate in tight spaces and to safely address to surgical sites. This research demonstrates a scalable steerable cannula for 360° arthroscopic capsular release (ACR) of the glenohumeral joint. The steerable cannula mainly consists of the pre-curved inner tube of nitinol, the straight outer tube of stainless steel, and the controller part. Using anisotropic patterns and heat treatment, the inner tube has a high degree of curvature. The mechanism controls the distal end with the two degrees of freedom. The inner tube can be translated and rotated relative to the outer tube. The steerable cannula was designed to avoid the axillary nerve under the inferior glenoid to minimize the risk of iatrogenic injury while keeping flexed to match the bony curvature of the glenohumeral joint. The cylindrical cannula can fit various surgical tools and can be sterilized after use. In porcine shoulder test and workspace analysis, the proposed cannula addressed the inferior glenoid that is not reachable by the conventional rigid cannula. Thus, the proposed mechanism can navigate through the narrow and curved anatomical space of the glenoid cavity and reduce the unreachable area for ACR.Clinical Relevance- The propose cannula can be used for 360° arthroscopic capsular release (ACR) in minimally invasive surgery (MIS). This cannula can prevent damage to the axillary nerves which is one of the main complications of ACR. The mechanism has the potentials to reduce the unreachable area in MIS for knee and hip joints.

Glenohumeral Malalignment in the Hemiplegic Shoulder. An Early Radiologic Sign

A new radiologic sign is described which seems to diagnose an early presubluxation phase of glenohumeral malalignment in hemiplegic shoulders. The sign consists of a V-shaped widening of the upper part of the space between the humeral head and the glenoid cavity on anteroposterior shoulder films in the erect position. Twelve of 14 patients showing this sign went on to develop chronically painful shoulders, and four of them developed radiologically evident subluxation within several months. The sign may be helpful in diagnosing shoulder pathology following stroke at an early stage, when orthotic measures may still have preventive value.

The Biomechanical Effect of Bone Grafting and Bone Graft Remodeling in Patients With Anterior Shoulder Instability

Background: Individual constitutional differences in glenoid shape and bone remodeling require a patient-specific and longitudinal approach to evaluate the biomechanical effects of glenoid bone grafting in patients with anterior shoulder instability. Purpose: To quantify the longitudinal, in vivo, biomechanical effects of bone grafting, bone graft remodeling, and glenoid shape in patients with anterior shoulder instability by means of patient-specific finite element models. Study Design: Descriptive laboratory study. Methods: In total, 25 shoulders of 24 patients with anterior shoulder instability and anterior glenoid bone loss underwent an arthroscopic iliac crest bone graft transfer (ICBGT) procedure with either autologous or allogenic bone. Patient-specific finite element simulations based on preoperative, postoperative, and follow-up computed tomography scans were used to quantify the bone-mediated stability ratio (SR) and the distance to dislocation. Additionally, the relationship between glenoid morphological parameters and the SR was assessed. Results: The ICBGT procedure significantly increased the SR and distance to dislocation in the 2-, 3-, and 4-o’clock directions immediately after the surgical intervention (P < .01) in both the autograft and the allograft groups. Although the SR and distance to dislocation decreased subsequently, autografts showed long-term effects on SR and dislocation distance in the 3-o’clock direction (P < .01) and on SR in the 4-o’clock direction (P < .01). Allografts showed no significant effect on SR and dislocation distance in long-term follow-up (P > .05). Overall, glenoid retroversion as well as cavity depth predicted stability in all 4 dislocation directions, with glenoid cavity depth showing the highest correlation coefficients (R = 0.71, 0.8, 0.73, and 0.7 for 2-, 3-, 4-, and 5-o’clock, respectively). Conclusion: The autologous ICBGT procedure biomechanically improved anterior shoulder stability in long-term follow-up, whereas the use of allografts did not show any bone-mediated biomechanical effect at follow-up due to resorption. Furthermore, in addition to measurements of defect extent, the glenoid depth and version seem to be useful parameters to determine the biomechanical effect and need for glenoid bone grafting in patients with shoulder instability. Clinical Relevance: This study proposes the use of autologous bone grafts for a successful long-term stabilization effect. Additionally, this study proposes additional glenoid morphological measures to predict shoulder stability.