Retroversion Angle Research Articles

Do individualized humeral retroversion and subscapularis repair affect the clinical outcomes of reverse total shoulder arthroplasty?

This study aimed to evaluate the effects of an individualized angle of humeral retroversion and subscapularis repair on clinical outcomes after reverse total shoulder arthroplasty (RTSA) using a lateralized prosthesis. A retrospective analysis of 80 patients who underwent RTSA and had a minimum of 2 years' follow-up was performed. Individualization was based on the native retroversion angle, quantified from computed tomography images. Clinical outcomes (forward flexion, external rotation at the side, internal rotation at the back, functional scores, and pain) were compared between patients with individualized retroversion (group I, n = 52) and patients with a fixed retroversion angle of 20° (group II, n = 28). Group I was further subdivided into patients with a retroversion angle of 20° or less (subgroup A, n = 21) and patients with a retroversion angle greater than 20° (subgroup B, n = 31). We also compared outcomes in group I between patients with (n = 40) and without (n = 12) subscapularis repair. Ranges of motionincluding external rotation and internal rotation, functional scores, and pain relief were significantly better in group I than in group II (P < .05 for all). No differences in clinical outcomes were found between subgroups A and B, although outcomes for both of these subgroups were better than those for group II (P < .05 for all). Subscapularis repair was not correlated with superior clinical outcomes. Individualized humeral retroversion may provide superior clinical outcomes to those of implantation of the humeral component at a fixed angle of 20° of retroversion. Repair of the subscapularis may not be essential for superior clinical outcomes in patients treated using a lateralized RTSA prosthesis.

Analyse 3D pour prédire les résultats des fractures cervicales fémorales Garden 1 et 2 : une étude rétrospective multicentrique

IntroductionThe aim of our study was to (1) report our surgical outcomes of internal fixation in patients with nondisplaced or valgus impaction fractures of the femoral neck; (2) introduce our new three dimensional assessment method using a combination of X-ray and CT imaging, and (3) determine which radiologic measurements significantly predicted fixation failure. HypothesisWe hypothesized that high posterior tilt angle and retroversion angle are related to high incidence of non-union and osteonecrosis. Materials and methodsFrom January 2009 to December 2016, 64 elderly patients in two institutions with nondisplaced or valgus impaction fractures of the femoral neck who had internal fixation using multiple parallel cannulated screws were enrolled. To determine the independent predictors of non-union, osteonecrosis, and reoperation, various clinical variables and radiologic variables, including the valgus angle on coronal CT images, the posterior tilt angle on Lorenz images, and the retroversion angle on axial CT images, were analyzed. ResultsNon-union was identified in nine of the 64 patients (14.1%) and nine of the 55 patients (16.4%) who achieved bony union had femoral head osteonecrosis with subsequent segmental collapse. The multiple logistic regression model showed that a low bone mineral density of the femur, a higher posterior tilt angle on Lorenz image, and a higher retroversion angle on axial CT images were independent predictors of non-union and reoperation. DiscussionPrimary hip arthroplasty should be considered when a posterior tilt angle of more than 9 degrees on Lorenz images or a retroversion angle of more than 13 degrees on axial CT images is identified in patients with osteoporotic valgus impaction fractures. Type of study and level of proofIII, retrospective comparative study.

Three-dimensional analyses to predict surgical outcomes in non-displaced or valgus impaction fractures of the femoral neck: A multicenter retrospective study

IntroductionThe aim of our study was to (1) report our surgical outcomes of internal fixation in patients with non-displaced or valgus impaction fractures of the femoral neck, (2) introduce our new three-dimensional assessment method using a combination of X-ray and CT imaging, and (3) determine which radiologic measurements significantly predicted fixation failure. HypothesisWe hypothesized that high posterior tilt angle and retroversion angle are related to high incidence of non-union and osteonecrosis. Materials and methodsFrom January 2009 to December 2016, 64 elderly patients in two institutions with non-displaced or valgus impaction fractures of the femoral neck who had internal fixation using multiple parallel cannulated screws were enrolled. To determine the independent predictors of non-union, osteonecrosis, and re-operation, various clinical variables and radiologic variables, including the valgus angle on coronal CT images, the posterior tilt angle on Lorenz images, and the retroversion angle on axial CT images, were analyzed. ResultsNon-union was identified in nine of the 64 patients (14.1%) and nine of the 55 patients (16.4%) who achieved bony union had femoral head osteonecrosis with subsequent segmental collapse. The multiple logistic regression model showed that a low bone mineral density of the femur, a higher posterior tilt angle on Lorenz image, and a higher retroversion angle on axial CT images were independent predictors of non-union and re-operation. DiscussionPrimary hip arthroplasty should be considered when a posterior tilt angle of more than 9 degrees on Lorenz images or a retroversion angle of more than 13 degrees on axial CT images is identified in patients with osteoporotic valgus impaction fractures. Type of study and level of proofIII, Retrospective comparative study.

Evaluation of Bilateral Asymmetry in the Humerus of Human Skeletal Specimen.

Several studies have established a relationship between morphological and behavioral asymmetry making investigations of bilateral bone asymmetry an attractive and important research area. The purpose of this study was to investigate bilateral asymmetry patterns of skeletal specimen from five geographical locations (Rwanda, Burundi, Congo, Kenya, and Uganda) at Galloway Osteological Collection, Department of Anatomy, School of Biomedical Sciences, Makerere University College of Health Sciences. The angle of torsion and retroversion, mid-shaft circumference, length, and weight of 232 pairs of humeri were determined. A Torsiometer was used to measure the angle of torsion in degrees according to Krahl and Evans 1945, a tape was used to measure the mid-shaft circumference at the level of the apex of the deltoid V, and the length in cm was determined. An osteometric board was used to measure the length of the humerus in centimeters. A weighing balance was used to measure the weight of the humerus in grams. The analysis of humeral asymmetry with respect to parameters of the human skeletal specimen at the Galloway Osteological Collection Mulago revealed bilateral asymmetrical status observed in the angle of torsion, length, weight, and mid-shaft circumference. Our result mostly showed lateralization to the right in all the parameters investigated except the torsion angle which is to the left. Our investigation revealed that humeral torsion is inversely proportional to weight, length, and mid-shaft circumference of the humerus. This study established the existence of bilateral asymmetries in the humeri of all the geographical regions investigated with more asymmetry observed in the male compared with the female.

Glenoid retroversion is an important factor for humeral head centration and the biomechanics of posterior shoulder stability.

Glenoid retroversion is a known independent risk factor for recurrent posterior instability. The purpose was to investigate progressive angles of glenoid retroversion and their influence on humeral head centration and posterior translation with intact, detached, and repaired posterior labrum in a cadaveric human shoulder model. A total of 10 fresh-frozen human cadaveric shoulders were investigated for this study. After CT- canning, the glenoids were aligned parallel to the floor, with the capsule intact, and the humerus was fixed in 60° of abduction and neutral rotation. Version of the glenoid was created after wedge resection from posterior and fixed with an external fixator throughout the testing. Specimens underwent three conditions: intact, detached, and repaired posterior labrum, while version of the glenoid was set from + 5° anteversion to - 25° retroversion by 5° increments. Within the biomechanical setup, the glenohumeral joint was axially loaded (22N) to center the joint. At 0° of glenoid version and intact labrum, the initial position was used as baseline and served as point zero of centerization. After cyclic preloading, posterior translation force (20N) was then applied by a material testing machine, while start and endpoints of the scapula placed on an X-Y table were measured. The decentralization of the humeral head at glenoid version angles of 5°, 10°, 15°, and 20° of retroversion and 5° of anteversion was significantly different (P < 0.001). Every increment of 5° of retroversion led to an additional decentralization of the humeral head overall by (average ± SD) 2.0mm ± 0.3 in the intact and 2.0mm ± 0.7 in the detached labrum condition. The repaired showed significantly lower posterior translation compared to the intact condition at 10° (P = 0.012) and 15° (P < 0.01) of retroversion. In addition, CT measured parameters (depth, diameter, and native version) of the glenoid showed no correlation with angle of dislocation of each specimen. Bony alignment in terms of glenoid retroversion angle plays an important role in joint centration and posterior translation, especially in retroversion angles greater than 10°. Isolated posterior labrum repair has a significant effect on posterior translation in glenoid retroversion angles of 5° and 10°. Bony correction of glenoid version may be considered to address posterior shoulder instability with retroversion > 15°.

Étude anatomique de l’insertion et de l’orientation des ligaments coraco-claviculaires : différence de positionnement des tunnels de reconstruction selon le sexe

BackgroundReconstructing both coracoclavicular ligaments following acromioclavicular dislocation has recently been reported to restore the function of the acromioclavicular joint better than traditional procedures. Knowing the appropriate position and orientation of the bone tunnels and the potential risks of neurovascular injuries leads to safe reconstruction. We aimed to answer the following questions: what is the difference in the accurate clavicular bone tunnel positions (BTPs) during coracoclavicular ligament reconstruction between sex, and what are the potential risks for neurovascular injuries? HypothesisThe BTPs differ by sex at the site of coracoclavicular ligament reconstruction. Patients and methodsWe introduced two Kirschner wires into 25 cadaver shoulders (17 male, 8 female), one through the insertion center of the trapezoid ligament and one through the conoid ligament, and measured the distance from the respective Kirschner wire insertion points to the bony landmarks of the clavicle and the oblique angle of each Kirschner wire. The shortest distance from the insertion point of each Kirschner wire to the suprascapular nerve and artery was also measured. ResultsWhile the distance from the acromioclavicular joint to the respective Kirschner wire insertion points tended to be longer in males, the ratio of these insertion points to total clavicle length was constant. Other measurements for respective Kirschner wire insertions to the bony landmarks and neurovascular structures were comparable, as were abduction and retroversion angles. The distance from the suprascapular nerve to the insertion point of the conoid ligament at the coracoid process was 13.8±4.0mm, while the distance from the suprascapular artery was 7.1±3.3mm. DiscussionAppropriate position and orientation of the bone tunnels, and the ratio of the BTPs to the total clavicular length, aid surgeons in performing the reconstruction. The conoid ligament insertion on the coracoid was just proximal to the suprascapular artery, so surgeons should be careful with conoid insertion. Level of evidenceV, cadaver study.

A new geometric model to quantify the area of glenoid bone defect and medialisation of the native joint line in glenohumeral arthritis.

To propose a geometric model to quantify the bone defect and the glenoid medialisation (in millimetres) compared to the native joint line. We also evaluated the reliability of this geometric model. Using two-dimensional CT imaging, we built a hypothetical triangle on the axial scan consisting of the following: side A, length (millimetres) of the glenoid bone; side B, average length (millimetres) of the glenoid in a healthy population; side C, the missing side; and angle α, the retroversion angle calculated using the Friedman method. The resulting triangle represents the bone defect, and its height represents the medialisation of the native joint line. To estimate inter-operator reliability, two physicians (operator 1 and operator 2) took the following measurements: angle α, side A, side C, semi-perimeter, area defect and height. Forty participants (mean age ± SD 45 ± 10years, range 26-43years)-22 women and 18 men-participated in the study. We applied the cosine theorem (Carnot theorem) to calculate side C. After obtaining the three sides, the area of the triangle can be determined. Once the area is known, it is possible to extrapolate the height of the triangle, which corresponds to the loss of vault depth due to the bone defect. With respect to inter-operator reliability, the ICCs for all measurements were > 0.99, exhibiting a very high correlation. The proposed geometric model can be used to quantify the glenoid bone deficit and the glenoid medialisation compared to the native joint line, which can be used to improve surgical treatment.

Relationship between bilateral humeral retroversion angle and starting baseball age in skeletally mature baseball players—existence of watershed age

Repetitive pitching in childhood was thought to restrict the physiological derotation process of the humeral head. Some studies reported that the side-to-side differences of humeral retroversion in baseball players occurred between the age of 9 and 11 years. The present study investigated the relationship between bilateral humeral retroversion angle and starting baseball age in skeletally mature baseball players. One hundred and seventeen male baseball players, who belonged to a college or amateur team, were investigated. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique as described by previous studies. All players were divided into four groups: players who had started playing baseball before the age of 6 years, between 7 and 8 years, between 9 and 10 years and after 11 years. Bilateral humeral retroversion angle was compared among the four starting age groups. All players started playing baseball between 5 and 12 years. Comparing the throwing arm, humeral retroversion in starting age group 11-12 (72°) was significantly smaller than the other 3 groups (81°, 82°, and 80° for groups 5-6, 7-8, and 9-10, respectively). Comparing the non-throwing arm revealed no significant differences among the 4 starting age groups (71°, 72°, 70°, and 66° for groups 5-6, 7-8, 9-10, and 11-12, respectively). Skeletally mature baseball players who started playing baseball after 11 years had significantly smaller humeral retroversion in the throwing arm than those who started baseball before 11 years.

Does the change of retroversion angle effect the clinical results of conservative treatment of humerus diaphyseal fractures?

Does the change of retroversion angle effect the clinical results of conservative treatment of humerus diaphyseal fractures?

Anatomical study of the position and orientation of the coracoclavicular ligaments: Differences in bone tunnel position by gender

BackgroundReconstructing both coracoclavicular ligaments following acromioclavicular dislocation has recently been reported to restore the function of the acromioclavicular joint better than traditional procedures. Knowing the appropriate position and orientation of the bone tunnels and the potential risks of neurovascular injuries leads to safe reconstruction. We aimed to answer the following questions: what is the difference in the accurate clavicular bone tunnel positions (BTPs) during coracoclavicular ligament reconstruction between sex, and what are the potential risks for neurovascular injuries? HypothesisThe BTPs differ by sex at the site of coracoclavicular ligament reconstruction. Patients and methodsWe introduced two Kirschner wires into 25 cadaver shoulders (17 male, 8 female), one through the insertion center of the trapezoid ligament and one through the conoid ligament, and measured the distance from the respective Kirschner wire insertion points to the bony landmarks of the clavicle and the oblique angle of each Kirschner wire. The shortest distance from the insertion point of each Kirschner wire to the suprascapular nerve and artery was also measured. ResultsWhile the distance from the acromioclavicular joint to the respective Kirschner wire insertion points tended to be longer in males, the ratio of these insertion points to total clavicle length was constant. Other measurements for respective Kirschner wire insertions to the bony landmarks and neurovascular structures were comparable, as were abduction and retroversion angles. The distance from the suprascapular nerve to the insertion point of the conoid ligament at the coracoid process was 13.8±4.0mm, while the distance from the suprascapular artery was 7.1±3.3mm. DiscussionAppropriate position and orientation of the bone tunnels, and the ratio of the BTPs to the total clavicular length, aid surgeons in performing the reconstruction. The conoid ligament insertion on the coracoid was just proximal to the suprascapular artery, so surgeons should be careful with conoid insertion. Level of evidenceV, cadaver study.

Posterior open wedge glenoid osteotomy provides reliable results in young patients with increased glenoid retroversion and posterior shoulder instability.

The relationship between posterior shoulder instability and increased glenoid retroversion has been documented. Posterior open wedge glenoid osteotomy is a possible treatment option for patients with increased glenoid retroversion, but outcomes in the literature are limited. Therefore, the purpose of this study was to report the clinical and radiological outcomes following posterior glenoid osteotomy. Patients that underwent posterior glenoid osteotomy for posterior shoulder instability with a GR angle of more than or equal to 10°, and were at least 12 months out from surgery, were included in the study. General data, medical history, and radiographic data such as the pre- and postoperative glenoid retroversion angle were extracted from the patients' hospital documentation notes. To evaluate the postoperative outcome, the Rowe standard rating scale for shoulder instability and the Oxford shoulder instability score were collected retrospectively. A total of 12 shoulders (11 patients) could be included. The mean pre-operative glenoid retroversion was 23.3° (range 12°-35°) and this reduced significantly (p = 0.003) to a mean of 13° (range 1°-28°) postoperatively. At a mean follow-up of 19.8 months (range 14-36), the median Rowe score was 90 points (range 45-100 points) and the median Oxford instability score was 44 points (range 21-48 points). There were no postoperative re-dislocations or revision surgeries; however, one patient reported signs of recurrent shoulder instability and four asymptomatic glenoid neck fractures occurred. Open wedge posterior glenoid osteotomy provides reliable clinical results with a low rate of clinical failure in a stringently selected patient cohort at short-term follow-up. However, due to the risk of potentially severe complications, we advocate this procedure for experienced shoulder surgeons only, who are familiar with its anatomical and technical considerations. IV (case series).

Multilevel glenoid morphology and retroversion assessment in Walch B2 and B3 types.

A major factor that impacts the long-term outcome and complication rates of total shoulder arthroplasty is the preoperative posterior glenoid bone loss quantified by glenoid retroversion. The purpose of this study was to assess if glenoid retroversion varies significantly at different glenoid heights in Walch B2 and B3 glenoids. Patients with B2 and B3 glenoid types were included following retrospective review of 386 consecutive CT shoulder studies performed for arthroplasty preoperative planning. True axial CT reconstructions were created using a validated technique. Two readers independently measured the glenoid retroversion angles according to the Friedman method using the "intermediate" glenoid at three glenoid heights: 75% (upper), 50% (equator), and 25% (lower). The variances between the three levels for a given patient were calculated. Twenty-nine B2 and 8 B3 glenoid types were included. There was no significant difference in variance of glenoid version among the three levels in B2 or B3 groups. The mean variance in retroversion degree between equator-lower, upper-equator, and upper-lower glenoid was -0.4, 0.3, and - 0.2 for B2; and - 0.2, 1.9, and 1.9 for B3 glenoid, respectively. The level of inter-reader agreement was fair to good for variance at equator-lower, and good to excellent for upper-equator and upper-lower glenoid. Glenoid version can be accurately measured at any level between 25 and 75% of glenoid height for Walch B2 and B3. We recommend that the glenoid equator be used as the reference to assure consistent and reliable version measurements in this group of patients.

Comparison of Kinetic Characteristics of COM and Retroversion Angle between National Taekwondo Demonstration Team Members and College Taekwondo Demonstration Team Members when Perform Jumping Break

Comparison of Kinetic Characteristics of COM and Retroversion Angle between National Taekwondo Demonstration Team Members and College Taekwondo Demonstration Team Members when Perform Jumping Break

Shoulder hemiarthroplasty assisted by individualized navigation templates 3D printed

Objective To investigate the efficacy and accuracy of 3D printing individualized navi-gation templates used in shoulder hemi-arthroplasty (HA). Methods We collected 9 adult cadaveric specimens of 18 shoulders with no obvious deformities or defects. After CT scanning was conducted on bilateral shoulders, the raw CT data in DICOM format were imported into software Mimics 10.01 and Imageware 12.0 to reconstruct 3D shoulder models. The retroversion angles and heights of bilateral humeral heads were mea-sured to design individualized navigational templates using software Geomagic Studio 12.0. Rapid prototyping (RP) technique was used to manufacture the individualized navigation templates which were then used to assist shoulder HA in cadaveric specimens. CT scanning was performed postoperatively to measure the retroversion angle and height of the prosthesis implanted for comparison with the preoperative measurements. Results Before shoulder replacement in the 9 cadaveric specimens, respectively, the heights of left and right humeral heads averaged 300.0±11.6 mm and 300.0±11.4 mm, and the retroversion angles 15.6°±4.9° and 15.9°±4.9°. After the replacement, the heights of left and right humeral heads averaged 300.0±11.3 mm and 300.0±11.7 mm, respectively, and the retroversion angles 15.7°±4.9° and 15.8°±5.2°, respectively. There were no significant differences between the left and right sides in the pre- or post-operative heights or retroversion angles of the humeral head (P >0.05). There were no significant differences either between pre- and post-operation in the heights or retroversion angles of the left and right humeral heads (P >0.05). The mean errors for the preoperative and postoperative heights and retroversion angles of the humeral heads were 1.44±0.96 mm and 0.25°±0.15°, respectively. Conclusion Individualized navigation templates 3D printed can be used to assist effective and accurate shoulder HA because they are designed and manufactured according to accurate measurements of retroversion angles and heights of the humeral heads which are acquired by computer preoperatively. Key words: Computer-aided design; Shoulder; Arthroplasty, replacement; 3D printing technology

Remodeling after arthroscopic reduction of glenohumeral joint in adduction internal rotation shoulder deformity in obstetric brachial plexus palsy

Background: Lesions of the upper trunk in obstetric brachial plexus palsy (OBPP) commonly leads to long-term shoulder dysfunction. The constant internal rotation lead to early glenohumeral (GH) joint deformity by 6 mo of age and to advanced deformity by 2 yr. Halting or reversing GH deformity and the percentage of the humeral head anterior to the midscapular line is an important surgical goal to restore shoulder function. The purpose of this study was to assess the ability of arthroscopic anterior release (with or without tendon transfers) to correct GH deformity. Methods: Twenty-one patients were included in this study. The average age was 26 mo (17 to 50 mo). Sixteen patients (76.2%) had C5 or 6 lesion, while five (23.8%) had C5, 6 or 7 lesion. Seven patients had grade II GH deformity (33.3%), ten had grade III (47.6%), and four had grade IV (19.1%). Ten children underwent isolated release and 11 underwent concomitant tendon transfers. Functional and radiographic assessments were used to assess outcome after at least 1-year follow-up. The average follow-up period was 19±7 mo (range 12-41 mo). Results: Significant improvement was noted in both the glenohumeral retroversion angle (GRV) angle and percentage of humeral head anterior to the midscapular line at 1-year follow-up The mean preoperative GRV angle was −27.8 degrees and postoperatively −11.8 degrees. The mean percentage of humeral head anterior to the midscapular line was 25% preoperatively and 43% postoperatively. Aggregate Mallet score also demonstrated statistically significant improvement. Conclusions: Arthroscopic release and reduction of GH joint with or without tendon transfer for the sequela of OBPP was associated with GH remodeling. The current study confirmed that the improvement was achieved after nearly 1-year follow-up. The clinical improvements paralleled the radiographic ones. Level of evidence: IV.

Linear relationship between lateralization of the bicipital groove and humeral retroversion and its link with the biepicondylar humeral line. Anatomical study of seventy cadaveric humerus scans.

Morphological studies of the humerus have shown that the position of the bicipital groove varies with the individual and the retroversion of the humeral head. Depending on the authors, these two parameters are independent or associated. This study evaluated the relationship between the humeral head axis and its retroversion and the bicipital groove relative to the humeral biepicondylar line. Seventy cadaveric humeri were scanned to obtain 3D reconstructions. Views of the 3D reconstruction from above showed the bicondylar line, the bicipital groove and the humeral head on a single image. After measuring the humeral retroversion angle and the bicipital groove angle relative to the bicondylar line, we assessed the relationship between these two angles with Pearson's correlation coefficient. Pearson's correlation coefficient indicated a significant linear correlation between the angle of the groove and the angle of humeral retroversion based on the 70 cadaveric humeral bones (the p-value was 7.510-7, the correlation coefficient was -0.5515, and the 95% confidence interval was (-0.6962; -0.3636)). Our study thus demonstrates that the less lateralized the bicipital groove is, the greater the humeral retroversion will be. We demonstrated a linear relationship between humeral head retroversion and bicipital groove lateralization. Within our reliability interval, this relationship can be used in clinical practice to evaluate retroversion without resorting to CT of the entire humerus.

Effects of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: Finite element modeling of cadaver specimens

A novel technique of “anterior offsetting” of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen׳s actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p < 0.05) except for total force (p < 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future.

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors

BackgroundPlacement of the glenoid baseplate is of paramount importance for the outcome of anatomical and reverse total shoulder arthroplasty. However, the database around glenoid size is poor, particularly regarding small scapulae, for example, in women and smaller individuals, and is derived from different methodological approaches. In this multimodality cadaver study, we systematically examined the glenoid using morphological and 3D-CT measurements.MethodsMeasurements of the glenoid and drill hole tunnel length for superior baseplate screw placement were recorded to define size of the glenoid and the distance to the scapular notch on cadaveric specimens. Glenoid angles were determined on both, 3D-CT-scans of the thoraxes using the Friedman method and on subsequently isolated scapulae from 18 male and female donors (average 84 years, range 60–98 years).ResultsMean glenoid height was 36.6 mm ± 3.6, and width 27.8 mm ± 3.1 with a significant sex dimorphism (p ≤ 0.001): in males, glenoid height 39.5 mm ± 3.5, and width 30.3 mm ± 3.3, and in females, glenoid height 34.8 mm ± 2.2, and width 26.2 mm ± 1.6. The average distance from the superior screw entry to its exit in the scapular notch measured by calliper was 27.2 mm ± 6.0 with a sex difference: in males, 29.4 mm ± 5.7, and in females, 25.8 mm ± 5.9 mm with a minimum recorded distance of 15 mm. Measured by CT, the mean inclination angle for male and female donors combined was 13.0° ± 7.0, and the ante-/retroversion angle −1.0° ± 4.0°.ConclusionThis study is one of the first to combine dissection, including drill holes, with anatomical measurements and radiological data. In some women and smaller individuals, smaller baseplates should be selected. The published safe zone of 20 mm is generally feasible for superior screw placement, however, in small patients this distance may be substantially shorter than expected and start as of 13 and 15 mm, respectively. No correlation between glenoid height or width with the length of our drilling canal towards the scapular notch was found. Preoperative CT-based treatment planning to determine version and inclination angles is recommended.

MR Arthrography versus conventional MRI in evaluation of labral and chondral lesions in different types of femoroacetabular impingement

ObjectiveTo detect the value of MR Arthrography over MRI in evaluation of labral and chondral lesions in all types of FAI, and to correlate the findings with arthroscopy as a gold standard. Patients and methods50 patients including 33 males and 17 females, age ranges from 19 to 54years old (mean age 39±5.5), underwent MRI and MR Arthrography of the hip joint followed by arthroscopy correlation. Images were evaluated for labral abnormalities, cartilage and osseous abnormalities associated in FAI. α angle. Acetabular lateral edge angle and degree of focal retroversion were measured. ResultsCam type detected in 20, Mixed type in 28, pincer type in 2, MRI detected 28 labral injury, 51 cartilage affection in 33 cases, MR Arthrography detected 38 labral injury, fraying of the L/C zone in 23 cases, 53 cartilage affection in 33 cases, cam type ch.ch by large α angle, anterosuperior femoral cartilage lesion and osseous bump formation; mixed type include the previous cam findings with a deep acetabulum and posteroinferior cartilage lesions. Anterosuperior labral (AS) tears are more common than postersuperior (PS). ConclusionHip MR Arthrography is a faithful evaluation modality for diagnosing the acetabular labral tears, and cartilage abnormalities associated with different types of FAI.

Distinct Proximal Humeral Geometry in Chinese Population and Clinical Relevance.

Replicating humeral anatomy during shoulder arthroplasty is important for good patient outcomes. The proximal humeral geometry of the Chinese population has been rarely reported. We analyzed the geometry of the proximal part of the humerus in Chinese subjects and compared it with that of Western populations and the dimensions of available prostheses. Eighty healthy Chinese subjects underwent computed tomography (CT)-arthrography. Three-dimensional (3D) digital humeral and glenoid models were reconstructed, and geometric parameters were measured. Humeral measurements included the radius of curvature, articular surface diameter and thickness, anterior-posterior/superior-inferior (AP/SI) articular surface diameter ratio, articular surface thickness/radius of curvature ratio, surface arc, inclination angle, retroversion angle, and medial and posterior offsets. Glenoid measurements included SI length, AP length, SI radius, and AP radius. The average radius of curvature (and standard deviation) of the humeral head was 22.1 ± 1.9 mm, the articular surface diameter averaged 42.9 ± 3.6 mm, and the articular surface thickness averaged 16.9 ± 1.5 mm. There was strong linear correlation between the articular surface diameter and thickness (r = 0.696, p = 0.001), with a linear regression relationship of thickness = 0.357 × diameter + 1.615. The AP/SI articular surface diameter ratio averaged 0.93 ± 0.03; the articular surface thickness/radius of curvature ratio, 0.77 ± 0.05; the surface arc, 153° ± 5.6°; the inclination angle, 133° ± 3.1°; and the retroversion angle, 22.6° ± 10.2°. The medial and posterior offsets averaged 6.3 ± 0.9 mm and 0.4 ± 0.78 mm, respectively; the SI and AP lengths, 30.15 ± 3.70 mm and 20.35 ± 2.56 mm; and the SI and AP radii, 23.49 ± 2.48 mm and 25.54 ± 3.07 mm. Compared with the Western population, the Chinese cohort had a smaller radius of curvature (p < 0.001), smaller articular surface diameter (p = 0.009), larger articular surface thickness/radius of curvature ratio (p < 0.001), larger surface arc (p < 0.001), smaller inclination angle (p < 0.001), and smaller posterior offset (p < 0.001). Unlike the Western population, the Chinese population had higher glenohumeral conformity in the coronal plane than in the axial plane. Many manufacturers' shoulder prostheses do not adequately cover the range of humeral head dimensions in our Chinese cohort. The geometric parameters of the humeri in the Chinese population differ from those in other populations. These differences have clinical relevance with regard to implant design and arthroplasty technique and likely affect clinical outcomes.