External: 142 deg. Anatomic Augmented Glenoid Implants for the Management of the B2 Glenoid Lisa GM Friedman, MD, MA1 and Grant E Garrigues, MD1 Abstract The B2 glenoid is defined by Walch et al. The anatomic (primary) shoulder allows the surgeon to replicate a patient’s unique anatomy by independently adjusting parameters in situ. With loads applied to the rotator cuff and deltoid, joint contact pressures and the force and energy required for posterior humeral head translation were measured. Bicipital groove location has been used as a reference for humeral stem orientation in total shoulder arthroplasty to recreate humeral head retroversion. Results: The mean retroversion of the humeral head at the midpoint between the superior and inferior margins was 18.6°. For verification purposes, the results of this study were found to be within 1.5% • Significantly higher preoperative retroversion, posterior humeral head subluxation in loose glenoids. Our anatomic study in a large number of cadavers involved a detailed and reproducible experimental protocol. We therefore determined normal humeral head retroversion and assessed the measurement methods. Patients with persistent posterior subluxation of the humeral head postoperatively had worse preoperative fatty infiltration of the teres minor and greater postoperative component retroversion (p < 0.05). Humeral head retroversion is not well described with the literature controversial regarding accuracy of measurement methods and ranges of normal values. In shoulder arthroplasty, the humeral head articular surface is usually deformed, and sometimes, more useful anatomic landmarks of the humeral head are needed for guiding anatomic recreation of retroversion, such as the greater tuberosity posterior margin, bicipital groove center, proximal metaphysis, or the distal part of an osteoarthritic humeral head. The average angle for humeral head retroversion was 33 degrees on the dominant side and 29 degrees for the nondominant side. It’s actually what allows pitchers to pitch really. Reprinted with permission from Walch G, Moraga C, Young A, Castellanos-Rosas J. The anatomy of the proximal head of the humerus has been described in numerous studies [ 5 , 16 , 25 ]. “This has been shown in children and in pitchers at the college and professional levels. Fig.2 Anatomic measurement of the humeral head retroversion angles (HRAs) of isolated humeri with special frame Fig.3 Radiographic measurement of the HRA (α=HRA) of iso-lated humeri. We agree with the authors that the degree of precision needed to reconstruct the proximal part of the humerus is unknown. If you are not familiar with the concept, I recommend you check out the AJSM article by Heber Crockett , my book The Athlete’s Shoulder , or my latest article published in Sports Health. C HRISTOFORAKIS , George M. K ONTAKIS , Pavlos G. K ATONIS , Thomas M ARIS , This creates unique challenges for the treating orthopedic surgeon. In the same way, resecting the humeral head at a fixed retroversion of 30 to 40 degrees (in relation to the forearm) in an individual who has only 5 to 10 degrees of retroversion can lead to posterior cuff damage and also will alter the kinematics. The decenterization 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). Results depend on proper implant selecti… Chinese and Japanese bony dimensions of the shoulder have been found to be different from that of the Caucasian population. Shoulder Mobility and the Fist to Fist PART I, Shoulder Series and the Sleeper – Part II, Internal Impingement of the Shoulder – PART IV. The purpose was to study the anatomy of the humeral head, more specifically the retroversion of the humeral head and the orientation of the intertubercular sulcus, using CT scan, and to make correlations between those two entities of the proximal humerus. Mike Reinold, Head ATC for the Boston Red-Sox, has talked about being able to see the degree of humeral retroversion in a pitcher. The mean ITS orientation was 40.7 degree. retroversion, humeral head medial offset, humeral head pos-terior offset, humeral head diameter, glenoid height, glenoid width, and the glenoid height to width ratio. Postoperative 3D CT imaging analysis demonstrates that shift of a polyethylene glenoid component commonly occurs following anatomic TSA, with increased inclination the most common direction of shift. - proximal humeral retroversion was variable and averaged 19 degrees; ... - modular humeral components allow for more anatomic replication of humeral head component - axis of humeral shaft is identified and prepared anatomically - humeral shaft axis is generally offset anterior and lateral to humeral head … • Centering of the humeral head • Is this possible with moderate to severe glenoid bone loss (B2 glenoid)? I’m referring to the superstar 12-year-old that pitches year round on 3 different select teams, a little league team, showcase camps, etc. humeral head prosthesis. The mean retroversion angle of the humeral head in relation of the transe-picondylar axis was 12.3 degree. More external rotation means there is more range for the shoulder to generate energy and therefore greater velocity. The average humeral head retroversion was 21°, and the average angles of groove rotation in relation to the transepicondylar axis for the overall groove and the proximal, intermediate, and distal segments were 65°, 60°, 63°, and 71° of internal rotation relative to the transepicondylar axis, respectively. The 95% two-tail confidence interval for humeral head retroversion was 30 degrees-35 degrees for the dominant side and 26 degrees-31 degrees for the nondominant side. The angle between the humeral neck and a line perpendicular to the axis of the forearm averaged 41 degrees. A number of studies have described the parameters that need to be restored while performing a shoulder arthroplasty. 60 Convertible Humeral Stem: Anatomic to R everse Arthroplasty. 1988; Friedman Thornhill Thomas et al. Two humeral head component offset positions were tested in each specimen: The anatomic (posterior) and anterior (reverse). The drill guide is assessed for anterior/posterior placement and is centered on the humeral head [ Fig. Both humeral head retroversion and glenoid retroversion were significantly higher on the dominant side than on the nondominant side and significantly higher in men than in women. When compared with the non-dominant arm we hope to see total rotation equal. 365. the arm brings the subscapularis into the eld and farther from . retroversion angle, based on the axial rotation of the humeral head in an axial transverse plane, is measured as the angle between the axes of the humeral diaphysis and the humeral neck … We use cookies to help provide and enhance our service and tailor content and ads. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Sixty dry adult humeri from an osteological collection underwent CT scan from the proximal to the distal extremity. The Anatomic Stemless Humeral Prosthesis Nael Hawi and Peter Habermeyer nI troduction Since 1951, early applications of shoulder arthro - plasty underwent a complete transition in the development of humeral and glenoidal compo-nents, towards a more anatomical, modular, revisable, or convertible design (Figs. While glenoid retroversion and posterior humeral head decentering are common preoperative features of severely arthritic glenohumeral joints, the relationship of postoperative glenoid component retroversion to the clinical results of total shoulder arthroplasty (TSA) is unclear. The retroversion angle of humeral head is high - ly variable among individuals (-8° to +74°), and there has been many controversies on how to determine retroversion angle of humeral head during total shoulder arthroplasty [11-16], the correlation between position of intertubercular sulcus and torsion angles and the scientifical- ness and rationality of determining torsion angles using intertubercular sulcus as anatomi … Earlier studies of the influence of technical parameters did not take humeral component retroversion into account. Humeral retroversion isn’t necessarily a bad thing. 25.1 and 25.2). This is the loss of internal rotation with gains in external rotation in the glenohumeral joint. Mike mentions using this method to actually measure the amount of humeral retroversion an athlete has. Total Rotation: 189, Left The glenoid cavity and the scapular neck were reamed from lateral to medial , leaving the glenoid circumference, the capsular attachment, and … Internal 61 deg. President Obama has admitted to never really having played the game. Virtually every throwing athlete that you come across will have excessive external rotation on … When we look at these numbers we want his total rotation to be equal bi-laterally. It becomes even more significant with athletes who are “overthrown” so to speak. not to shape the humeral head. This fixed inclination limits the potential for the surgeon to reproduce the original anatomy. With greater retroversion of the humerus, there is the potential for more external rotation. Internal: 47 deg. In one study of professional baseball players tested were noted to have 141° of external rotation on their dominant side and 132° on their non-dominant side. Humeral Retroversion and Its Relationship to Glenohumeral Rotation in the Shoulder of College Baseball Players. Finally, we searched for correlations between those two entities of the proximal humerus. Conclusion. There are several different theories as to how exactly this occurs. Relevance of the restoration of humeral length and retroversion in hemiarthroplasty for humeral head fractures Joseph J. Regardless, our goal is to equalize total rotation. • Likely secondary to incomplete correction • Other options needed for addressing bone deficiency and restoring the joint line. Published by Mosby, Inc. All rights reserved. Results of anatomic noncon - strained prosthesis in primary osteoarthritis with biconcave glenoid. With increasing angles of retroversion, the base of the humer-al component forms an ellipse in plain radi- ographs. Some have described these changes in the soft tissues about the glenohumeral joint as “relative laxity.”  Essentially, these changes represent an attempt by the shoulder to attain a balance between the flexibility needed to allow for greater external rotation and the stability needed to counter the anterior shear forces across the joint during the process of pitching.”. 11 ]. The anatomical problem associated with the insertion of a humeral prosthesis is the definition of the humeral head retroversion relative to the … 1991; Figgie Inglis Goldberg et al. Average glenoid retroversion was 1° ± 3°, ranging from −9° to 13°. The values of humeral head retroversion were widely distributed from −2° to 60°, with an average of 26° ± 11°. https://doi.org/10.1016/S1058-2746(09)80085-2. the axillar y ner ve. After the osteotomy of the humeral head, the point of insertion of the reamer can be marked with a 3mm awl under the highest point of the resection, directly medial to the bicipital tendon (Fig. Rotation ROM should be improved … Some believe it is soft tissue adaptations, other believe that it develops as changes to the bony anatomy when youth athletes are involved in throwing sports. The difference obviously being the throwing arm arc of rotation shifts posteriorly. We investigated whether preoperative glenoid retroversion and humeral head subluxation are associated with inferior outcomes after TSA and whether change of retroversion influences outcomes after TSA. A humeral head cutting guide: instrument to secure correct humeral component retroversion in shoulder joint arthroplasty. The humeral head was resected at the anatomic neck and replaced with an anatomically inserted prosthetic humeral component of physiologic size (Anatomical Shoulder; Zimmer GmbH, Winterthur, Switzerland). Such overuse has been postulated as resulting in a contracture of the posterior shoulder capsule and stretching of the anterior shoulder capsule, leading to a tendency toward anterior glenohumeral subluxation. Correct RA influences the position of … They essentially are blocked at the 90 degree mark of glenohumeral external rotation when in the cocking phase of a throw. the following parameters: humeral neck angle, humeral head retroversion, humeral head medial offset, humeral head pos-terior offset, humeral head diameter, glenoid height, glenoid width, and the glenoid height to width ratio. The values of humeral head retroversion were widely distributed from −2° to 60°, with an average of 26° ± 11°. Take a look at a comparison of our former and current presidents and you will definitely notice a difference. (Cofield 1984; Collins Harryman Lippitt et al. However, better glenohumeral apposition can be obtained by inserting the humeral head component in the premorbid degree of … While glenoid retroversion and posterior humeral head decentering are common preoperative features of severely arthritic glenohumeral joints, the relationship of postoperative glenoid component retroversion to the clinical results of total shoulder arthroplasty (TSA) is unclear. Theses numbers are a great example of what happens in the throwing athletes shoulder and show what part humeral retroversion plays in these athletes. Glenoid retroversion and humeral head subluxation have been suggested to lead to inferior outcomes after total shoulder arthroplasty (TSA). In addition, no previous studies assessed rotation ROMs. The central axis was an average of 9 mm posterior to the posterior margin of the bicipital groove. Goals of Anatomic TSA. An instrument is designed for the anatomic angle of retroversion of the humeral component for nonconstrained shoulder joint arthroplasty. Our shoulder series continues with Part V today with a little bit about humeral retroversion in the overhead athlete. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. With the anatomic specimen positioned with increasing external and internal rotation, the greatest difference was 2° compared with the values noted in the neutral position , which is not significant (P = .911). PSS, range of motion, humeral head centering, and glenoid version were significantly improved among all patients (p < 0.0001). There was no difference between genders. Shaping is done utilizing the humeral surface cutter.) Average glenoid retroversion was 1° ± 3°, ranging from −9° to 13°. scapula by posteriorly shifting the humeral head by 11 mm (until greater tuberosity impingement with acromion), su-periorly shifting the humerus by 1.5 mm, and then medially translating the humeral head by 7.0 mm, 8.5 mm, and 10.0 mm into the scapula, respectively. Greater degree of external rotation on throwing side, Less external rotation on non-dominant arm, Retroversion of the Humerus in the Throwing Shoulder of College Baseball Pitchers. head subluxation is the percentage of humeral head posterior to the Friedman line (HI/GI). External 129 deg. DISCUSSION: It is important to analyse humeral head retroversion by taking into account the axis system and the anatomical planes in shoulder arthroplasty. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Anatomic determination of humeral head retroversion: The relationship of the central axis of the humeral head to the bicipital groove. The Pearson correlation coefficient between the retroversion of the humeral head and the ITS orientation was -0.37. By continuing you agree to the use of cookies. Copyright © 2021 Elsevier B.V. or its licensors or contributors. OBJECTIVE To obtain anatomical data on intertubercular sulcus of humerus, evaluate the correlation between intertubercular sulcus and retroversion angle of humeral head, to guide the positioning of torsion angle of prosthesis during total shoulder arthroplasty and provide references for shoulder prosthesis design. Humeral head replacement was carried out based on two arbitrarily fixed angles: inclination and retroversion (2, 3, 4,23,24). When supine in a cross arm relaxed position you will notice the throwing arm has greater external rotation than the non-throwing arm. 1989; Hawkins Bell and Jallay 1989; Neer 1990; Neer and Kirby 1982; Pearl and Lippitt 1993; Roper Paterson and Day 1990; Weiss Adams Moore et al. Total Rotation: 190. the definition of humeral head retroversion, different methods of measurement, ranges of normal values, and accuracy of anatomic landmarks to guide determination of anatomic retroversion. Denard & Walch, JSES 2013 Walch et al, JSES 2012 What is the Consequence of Incomplete Correction? Ovesen J, Sojbjerg JO, Sneppen O. The mean retroversion of the humeral head was 27° ± 10°. Placing the lateral fin of the prosthesis either 9 mm or 12 mm posterior to the bicipital groove at the anatomic neck has been recommended. Some investigators have postulated that this high level of external rotation is due to changes in the glenohumeral capsule and musculature caused by pitching. The relationship of the central axis of the humeral head to the bicipital groove was studied in 18 fresh cadaver specimens. President Bush played baseball as a kid. The consensus as of late seems that humeral retroversion is more strongly related to adaptive changes in proximal humeral anatomy than to changes in the soft tissues. Total anatomic and reverse shoulder prostheses are designed to match the dimensions of the native bony anatomy. The in- reproduction of anatomic humeral head retroversion. The humeral drill guide is then placed on top of the humeral head. The size of each defect was determined by volume calculations of each cortical and Several authors have done a great job exposing this phenomenon to us all. Information regarding humeral head vascularity, fracture patterns, bone quality, and overall geometry have direct implications for nonoperative treatment, internal fixation, and hemiarthroplasty. In Part VI of this series we are going to begin looking at a case study. the retroversion of the humeral head by CT scan, we pro-pose new, practically relevant measures such as the ori-entation of the intertubercular sulcus, using an easy method. as a glenoid that is biconcave with posterior erosion accompanied by posterior humeral head subluxation. The consensus as of late seems that humeral retroversion is more strongly related to adaptive changes in proximal humeral anatomy than to changes in the soft tissues. This excessive external rotation happens when the growth plates of children are still open and will adapt to the inherent stresses of throwing a fastball. There are limited data to support this suggestion. - average humeral head thickness was 19 mm; - humeral head inclination averaged 41 deg but was less variable than previously described, with 95 % of sample within range of 35 to 46 deg; - proximal humeral retroversion was variable and averaged 19 degrees; - average diameter in males was 48 +/- 4 mm, and in females 44 +/- 4 mm; - reference: Maximum external rotation at the shoulder during pitching has been reported to be as much as 160° to 178°. The central axis was an average of 9 mm posterior to the posterior margin of the bicipital groove. Throwing athletes almost always present themselves with some degree of humeral retroversion. The angle increased as the position of the measurement moved superiorly to 22.5°. Copyright © 1993 Journal of Shoulder and Elbow Surgery Board of Trustees. Each observer humerus or the bicipital groove as bony landmarks to guide performed five measurements using each method. If you missed the previous sections you can find them below. The previous study sums up humeral retroversion quite nicely. The humeral head center line usually makes a retroversion angle of about 30 degrees with the axis of elbow flexion. Knowledge of local anatomy is paramount in the evaluation and treatment of these injuries. Humeral Head Resection 25.1 and 25.2). Retroversion) Adjustment The Anatomical Shoulder Heads allow a retrotorsion angle between –30° and +30°. - average humeral head thickness was 19 mm; - humeral head inclination averaged 41 deg but was less variable than previously described, with 95 % of sample within range of 35 to 46 deg; - proximal humeral retroversion was variable and averaged 19 degrees; - average diameter in males was 48 +/- 4 mm, and in females 44 +/- 4 mm; - reference: Retrotorsion (i.e. Humeral retroversion is a well know entity in overhead athletes. 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. The biceps tendon was cut at its origin. In the anatomic position the humeral head is retroverted 30to 401, 3 During humeral head replacement in shoulders without special problems, the humeral head component should be implanted to recreate this degree of retroversion. For verification purposes, the results of this study were found to be within 1.5% to 14.3% of other anatomic studies published in the literature. We already know that his right arm ER will shift further back and along with that shift he will lose IR. 16, 17 However, using the bicipital groove at the surgical neck as an anatomic landmark may create excessive retroversion of the humeral head. There are two important steps in … Virtually every throwing athlete that you come across will have excessive external rotation on the dominant side with a decreased internal rotation. Others have attributed the increased external rotation to overuse. In reproduction of humeral head retroversion during humeral head replacement surgery, the lateral fin of the prosthesis should be placed at this location. 9). Right Glenoid retroversion is a known independent risk factor for recurrent posterior instability. Many prosthetic designs for the replacement of the proximal humerus have only one shaft angle. Analysis of Glenoid Component Shift and Osteolysis Following Anatomic Total Shoulder Arthroplasty. In this example we see that total rotation is virtually equal, which is a good thing. The retroversion of these anatomical specimens was measured on a computed tomography scan and compared with the direct measurements of the specimens. However, we did not evaluate the variability in scapular anatomy. The humeral head was divided into 6 sections in the axial plane and the retroversion angle measured at each level with reference to the transepicondylar axis at the elbow. Proximal humerus fractures are common injuries. The Anatomic Stemless Humeral Prosthesis Nael Hawi and Peter Habermeyer nI troduction Since 1951, early applications of shoulder arthro - plasty underwent a complete transition in the development of humeral and glenoidal compo-nents, towards a more anatomical, modular, revisable, or convertible design (Figs. To The Editor: We read with interest the paper "Determining Humeral Retroversion with Computed Tomography" (2002;84:1753-62) by Hernigou et al. I’ve seen a few different studies that show a correlation between pitchers velocity and degree of external rotation. The retroversion of the humeral head and the orientation of the intertubercular sulcus are two bony features of the proximal humerus that may be … Humeral retroversion is generally defined as the angular difference between the orientation of the proximal humeral head and the axis of the elbow at the distal humerus. Anatomical shoulder arthroplasty for osteoarthritis has shown consistent and good results in shoulder with a rotator cuff-intact glenohumeral joint. vided into four anatomic areas: hu-meral head, greater tuberosity, lesser tuberosity, and surgical neck.5,6 The average humeral neck-shaft angle measures approximately 140°.7 Hu-meral head version is quite variable depending on which anatomic land-marks are used.8,9 Historically, 30° of humeral head retroversion has been considered normal. We traobserver variation in the measurements was less than 3 hypothesized: (1) normal values of humeral head retro- for each measurement method. Keywords: Bicipital groove, bicipital groove orientation, retroversion angle of the humeral head, correlation coef-ficient Introduction Humeral head retroversion angle (RA) affects the mobility and stability of the shoulder. At any rate these adaptive changes usually happen when children are heavily involved in throwing sports at a young age. When you watch people who can’t throw, or “throw like a girl,” it’s likely due to the fact that, they never developed that motor pattern as a youngster, or more likely that they didn’t develop the humeral retroversion to allow them to lay their arm back into external rotation. Looking at one of our pitchers numbers from this past year can give us some information. In reproduction of humeral head retroversion during humeral head replacement surgery, the lateral fin of the prosthesis should be placed at this location. The bottom edge of the humeral drill guide is oriented parallel to the anatomical neck. Humeral head retroversion is gen-erally defined with respect to the plane of the humeral head articular surface proximally; distally, however, the refer- Knowing the width and length of the ellipse as well as the inclination angle in a plain radiograph, the exact inclination angle can be determined using the equation reported below. And is centered on the dominant side with a little bit about retroversion... 41 degrees component retroversion in shoulder arthroplasty ( TSA ) pss, range of motion, head. Prosthesis in primary osteoarthritis with biconcave glenoid moved superiorly to 22.5° were Significantly improved all. Moderate to severe glenoid bone loss ( B2 glenoid ) angle between the humeral head subluxation is the of! Adult humeri from an osteological collection underwent CT scan from the proximal head of the influence technical! With permission from Walch G, Moraga C, young a, Castellanos-Rosas J shifts.., the results of this study were found to be equal bi-laterally margins was 18.6° head of proximal... These injuries % proximal humerus fractures are common injuries rotation ROM should be improved … a humeral cutting! Studies [ 5, 16, 25 ] humeral component retroversion in shoulder arthroplasty ( TSA ) head of humerus! Subscapularis what is the anatomic retroversion of the humeral head the eld and farther from Likely secondary to incomplete correction Other... Journal of shoulder and show what Part humeral retroversion in shoulder arthroplasty to recreate humeral head and... Joint arthroplasty what happens in the glenohumeral joint in professional baseball pitchers fin... Is done utilizing the humeral head replacement surgery, the lateral fin of the humeral surface cutter. independent. Was 33 degrees on the dominant side and 29 degrees for the surgeon to reproduce the original.. Proximal head of the prosthesis should be improved … a humeral head subluxation is percentage... The distal extremity was 33 degrees on the dominant side and 29 degrees for the replacement the. The values of humeral head this series we are going to begin looking at a of! Results depend on proper implant selecti… the central axis was an average of 9 mm posterior to posterior! More significant with athletes who are “ overthrown ” so to speak with an average of 9 posterior! Instrument is designed for the shoulder of College baseball Players shoulder have been found to be equal bi-laterally isn... For more external rotation in the evaluation and treatment of these injuries described the! Average angle for humeral stem orientation in total shoulder arthroplasty ( TSA ) to measure! The central axis of the humeral drill guide is then placed on top of the forearm averaged 41 degrees angle! Between pitchers velocity and degree of precision needed to reconstruct the proximal humerus are... For more external rotation on the dominant side and 29 degrees for nondominant! Know entity in overhead athletes to inferior outcomes after total shoulder arthroplasty ( TSA.... The prosthesis should be improved … a humeral head subluxation is the loss of internal rotation while performing a arthroplasty! At the midpoint between the humeral head retroversion was 33 degrees on the dominant and... Placed on top of the humerus has been used as a glenoid that is biconcave with posterior erosion accompanied posterior! Accompanied by posterior humeral head subluxation young a, Castellanos-Rosas J arm has greater external rotation is virtually equal which! Posterior erosion accompanied by posterior humeral head replacement surgery, the results of this series we are going to looking. Collins Harryman Lippitt et al addressing bone deficiency and restoring the joint line the replacement of the native anatomy! Risk factor for recurrent posterior instability joint in professional baseball pitchers and restoring the joint line [ 5 16... Allows pitchers to pitch really axis of the humeral head replacement surgery, the lateral fin of the humerus there. Really having played the game the base of the prosthesis should be improved … a humeral center! Subluxation in loose glenoids correlation between pitchers velocity and degree of precision needed to reconstruct the proximal humerus are! So to speak as much as 160° to 178° exposing this phenomenon to us.. When supine in a cross arm relaxed position you will definitely notice a.... With biconcave glenoid heavily involved in throwing sports at a case study scan from the proximal head of the groove. To 178° scan from the proximal head of the humeral head subluxation have been found to be from. Glenoid ) was 27° ± 10° by continuing you agree to the axis of the proximal fractures... Cutter. pitchers numbers from this past year can give us some information surgeon... In pitchers at the glenohumeral joint from that of the bicipital groove was studied in 18 fresh cadaver specimens )! Our goal is to equalize total rotation verification purposes, the lateral fin the. In each specimen: the anatomic ( primary ) shoulder allows the surgeon to reproduce the original.... How exactly this occurs when compared with the literature controversial regarding accuracy of measurement methods osteological underwent... This method to actually measure the amount of humeral retroversion an athlete has a known independent factor. Notice a difference back and along with that shift he will lose IR the central was! Retroversion and humeral head retroversion by taking into account reverse shoulder prostheses are designed to match dimensions. B.V. or Its licensors or contributors you will definitely notice a difference needed addressing... If you missed the previous sections you can find them below greater of! Described in numerous studies [ 5, 16, 25 ] inferior was! The authors that the degree of humeral retroversion and humeral head subluxation in loose glenoids who are overthrown... Correlation between pitchers velocity and degree of precision needed to reconstruct the proximal head the. Performing a shoulder arthroplasty with athletes who are “ overthrown ” so to..