Component In Reverse Shoulder Arthroplasty Research Articles

Does forearm referencing using a retroversion guide achieve the targeted retroversion of the humeral component in reverse shoulder arthroplasty?

Component positioning affects clinical outcomes of reverse shoulder arthroplasty, which necessitates an implantation technique that is reproducible, consistent, and reliable. This study aims to assess the accuracy and precision of positioning the humeral component in planned retroversion using a forearm referencing guide. Computed Tomography (CT) scans of 54 patients (27 males and 27 females) who underwent primary reverse shoulder arthroplasty for osteoarthritis or cuff tear arthropathy were evaluated. A standardized surgical technique was used to place the humeral stem in 15° of retroversion. Version was assessed intraoperatively visualizing the retroversion guide from above and referencing the forearm axis. Metal subtraction techniques from postoperative CT images allowed for the generation of 3D models of the humerus and for evaluation of the humeral component position. Anatomical humeral plane and implant planes were defined and the retroversion 3D angle between identified planes was recorded for each patient. Accuracy and precision were assessed. A subgroup analysis evaluated differences between male and female patients. The humeral retroversion angle ranged from 0.9° to 22.8°. The majority (81%) of the measurements were less than 15°. Mean retroversion angle (± SD) was 9.9° ± 5.8° (95% CI 8.4°-11.5°) with a mean percent error with respect to 15° of -34% ± 38 (95% CI -23, -44). In the male subgroup (n=27, range 3.8° to 22.5°), the mean retroversion angle was 11.9° ± 5.4° (95% CI 9.8°-14.1°) with a mean percent error with respect to 15° of -21% ± 36 (95% CI -6, -35). In the female subgroup (n=27, range 0.9° to 22.8°), mean retroversion angle was 8.0° ± 5.5° (95% CI 5.8°-10.1°) and the mean percent error with respect to 15° was -47% ± 36 (95% CI -32, -61). The differences between the two gender groups were statistically significant (p=0.006). Referencing the forearm using an extramedullary forearm referencing system to position the humeral stem in a desired retroversion is neither accurate nor precise. There is a non-negligible tendency to achieve a lower retroversion than planned, and the error is more marked in females.

The base plate orientation angle: a plain radiographic technique for designing the base plate’s inclination in reverse shoulder arthroplasty

Superior inclination of the base plate in reverse shoulder arthroplasty (RSA) is underestimated and may lead to major setbacks in terms of functional outcomes due to the altered biomechanics. Joint instability, scapular notching, and loosening of the glenoid component are considered the most serious sequelae. Therefore, a thorough preoperative radiological assessment of the affected shoulder joint and customized design of the prosthesis according to the glenoid morphology are decisive and directly correlated to the outcome. In this article, we propose a simple radiographic technique to assess the inclination of the glenoid preoperatively, which identifies the need for intraoperative correction. One hundred inconspicuous shoulder radiographs were included in the control group (CG) to define the normal ranges of the base plate orientation angle (BOA) and the base plate correction angle (BCA). Further, both angles were measured on 2-dimensional (2D) computed tomography scans of patients with proximal humerus fractures as well as radiographs, 2D and 3-dimensional (3D) computed tomography scans of patients with cuff tear arthropathy who underwent RSA between 2018 and 2021. The interobserver reliability among three independent testers was evaluated by calculating the intraclass correlation coefficient. In cuff tear arthropathy cases, the BOA and BCA measurements on different imaging modalities were compared using the Wilcoxon test. Possible variations of both angles' values based on glenoid erosion types, according to the Favard classification, were also investigated. Regardless of the imaging modality used, the interobserver reliability was excellent among three independent observers. In the CG, the mean BOA and BCA values were 118°±6° and 17°±5°, respectively. The mean corrected BOA values of the CG and fracture group were 136°±5° and 140°±5°, respectively. In contrast to the BCA values, the BOA measurements on radiographs showed a statistically significant difference compared to those obtained on 2D- and 3D scans in the cuff arthropathy group. Further, both angles' values varied according to the extent and location of the glenoid erosion. The lowest mean BOA and highest mean BCA values were observed in cases with Favard glenoid type E3. The BOA and the BCA are reliable tools proposed to aid in precisely positioning the glenoid component in RSA in the preoperative setting. Whereas, the BOA determines the inclination of the inferior glenoid segment, the BCA represents the extent of correction required to obtain a neutral inclination of the base plate. Glenoid type E3 of the Favard classification with superior wear is particularly susceptible to base plate superior tilt.

Efficacy of fracture stem in reverse shoulder arthroplasty for 3- or 4-part proximal humerus fractures

BackgroundThis study compared the clinical results of fracture stems and conventional stems using the same glenoid component in reverse shoulder arthroplasty for proximal humerus fractures in the elderly. MethodsThis retrospective study included 35 patients who underwent Grammont-type reverse shoulder arthroplasty for proximal humerus fractures from 2014 to 2020. The average age at surgery was 79.2 (range, 65–92) years, with 33 female shoulders. Fracture types per Neer classification were 3-part fracture, 4-part fracture, in 13 and 22 shoulders, respectively. The final follow-up period was 35 (range, 24–81) months. The Constant score, American Shoulder and Elbow Surgeons score, shoulder range of motion, and healing of greater tuberosities at the final follow-up of AEQUALIS™ REVERSED (Conventional stem group: n = 15) and AEQUALIS™ REVERSED FX (Fractured stem group: n = 20) were retrospectively investigated. ResultsThere were no statistically significant differences in age at surgery, sex, body mass index, fracture type, waiting time from injury to surgery, or preoperative general condition between the groups. The Constant and American Shoulder and Elbow Surgeons scores of the fractured stem group were significantly higher than those of the conventional stem group (P = 0.038 and P = 0.023, respectively). The anterior elevation and external rotation at the side of the fractured stem group also showed significantly higher values than those of the conventional stem group (fractured stem group vs. conventional stem group: anterior elevation 127° ± 25° vs. 105° ± 35°, P = 0.041; external rotation 28° ± 13° vs. 13° ± 12°, P = 0.015). The greater tuberosity healing rate was 46.7% (7/15) in the conventional stem group and 85.0% (17/20) in the fractured stem group (P＝0.027). ConclusionsThe findings suggest that use of a fracture-specific stem rather than a conventional stem in Grammont-type reverse shoulder arthroplasty for proximal humerus fractures improves tuberosity healing, postoperative range of motion, and clinical scores.

COMPUTER TOMOGRAPHIC ANALYSIS OF THE GLENOID COMPONENT IN REVERSE SHOULDER ARTHROPLASTY

The positioning of the glTenoid component in RSA ( Reverse Shoulder Arthroplasty) is one of the factors determining implant survival and postoperative outcomes. Therefore, accurate determination of the glenoid version and inclination in RSA is essential for the surgeon - preoperatively to plan his work and postoperatively - to assess the outcome. Excessive retroversion and superior inclination are prerequisites for unsatisfactory results and are associated with a high frequency of revisions. The glenoid inclination is often described as the angle between the glenoid fossa line and the suprascapular reference line. The study included a 2-year follow-up of patients with reverse shoulder arthroplasty in the Department of Orthopedics. The analysis is based on pre / postoperative CT and three-dimensional reconstruction using Medi Cad software. A comparative analysis was made with the results obtained by X-ray examination. The results showed a high incidence of superior inclination of native glenoid fossae. The obtained ß-inclination angle averaged 13.8 °, and the difference in this radiographically measured parameter was 7.3 °. CT analysis preoperatively significantly improves the position of the glenoid component and avoids the superior inclination of the baseplate of the prosthesis.

Does fluoroscopy improve baseplate position compared to conventional technique in reverse shoulder arthroplasty? A preliminary study.

Accurate placement of glenoid component in reverse shoulder arthroplasty remains a challenge for surgeons of all levels of expertise; however, no studies have evaluated the utility of fluoroscopy as a surgical assistance method. Prospective comparative study of 33 patients undergoing primary reverse shoulder arthroplasty during a 12-month period. Fifteen patients had a baseplate placed using the conventional "free hand" technique (control group), and 18 patients using intraoperative fluoroscopy assistance group, in a case-control design. Postoperative glenoid position was evaluated on postoperative Computed Tomography (CT) scan. The mean deviation of version and inclination for fluoroscopy assistance vs. control group was 1.75° (0.675-3.125) vs. 4.2° (1.975-10.45) (p = .015), and 3.85° (0-7.225) vs. 10.35° (4.35-18.75) (p = .009). The distance from the central peg midpoint to the inferior glenoid rim (fluoroscopy assistance 14.61 mm/control 4.75 mm, p = .581) and the surgical time (fluoroscopy assistance 1.93 ± 0.57/control 2.18 ± 0.44 h, p = .400) showed no differences, with an average radiation dose of 0.45 mGy and fluoroscopy time of 14 s. Accurate axial and coronal scapular plane positioning of glenoid component is improved with intraoperative fluoroscopy at the cost of a greater radiation dose and without differences in surgical time. Comparative studies are needed to determine whether their use in relation to more expensive surgical assistance systems result in similar effectiveness.L evel of evidence : Level III, therapeutic study.

Radiographic changes around the glenoid component in primary reverse shoulder arthroplasty at mid-term follow-up

Some local events after reverse shoulder arthroplasty (RSA) occur without the patient experiencing symptoms and yet may be detected on diagnostic imaging, thereby serving as indicators of future complications that may require revision. Most of these events involve the glenoid component, but radiographic studies evaluating this component are scarce, especially medium- and long-term studies. This study aimed to analyze the radiographic changes around the glenoid component and determine the risk factors associated with the presence of these radiographic changes. A retrospective review of 105 primary Grammont-style RSAs implanted between 2003 and 2014 was conducted. Radiographic outcomes were evaluated in patients with ≥5 years of radiographic follow-up. Standardized digital radiographs obtained immediately postoperatively and at a minimum follow-up time of 5 years were analyzed to determine (1) glenoid component position (inclination and height) and (2) minor radiographic changes (Sirveaux grade 1 or 2 scapular notching; nondisplaced acromial fracture; radiolucent lines around 1 or 2 screws; Brooker grade 1a, 1b, or 2 heterotopic calcifications; or single screw rupture), as well as major radiographic changes (Sirveaux grade 3 or 4 scapular notching; radiolucent lines around ≥3 screws or central peg; Brooker grade 1c or 3 heterotopic calcifications; prosthetic dislocation; loosening or migration; or disassembly). Major radiologic changes were identified in 14.3% of the cases. Bivariate analysis showed that more changes were associated with the arthroplasties implanted in the first years of the study (odds ratio [OR] = 0.81, P = .012). This time-related variable was also associated with inclination (OR = 0.88, P = .045) and height (OR = 0.75, P = .001), improving in arthroplasties implanted in the last years of the study. Multivariate analysis revealed an increased risk of severe scapular notching mainly associated with superior tilt (OR = 2.52, P = .036) and a high (OR = 2.68, P = .019) or excessively high (OR = 7.55, P = .013) position and an increased risk of loosening signs associated with superior tilt (OR = 8.92, P = 9.1 × 10-6). The percentage of radiologic changes of the glenoid component in RSA is considerable, despite the detection of a decrease in their presence among the arthroplasties implanted outside the initial period. Superior tilt and an excessively high position appear to be associated with a severe degree of scapular notching development and increased risk of radiographic loosening signs. Knowledge of the factors associated with major radiologic changes in the medium-term follow-up will help to optimize the primary surgical technique for each patient and indication, improving implant survival in primary RSA surgery.

The reverse shoulder arthroplasty angle: a new measurement of glenoid inclination for reverse shoulder arthroplasty

Avoiding superior inclination of the glenoid component in reverse shoulder arthroplasty (RSA) is crucial. We hypothesized that superior inclination was underestimated in RSA. Our purpose was to describe and assess a new measurement of inclination for the inferior portion of the glenoid (where the baseplate rests). The study included 47 shoulders with rotator cuff tear arthropathy(mean age, 76 years). The reverse shoulder arthroplasty angle (RSA angle), defined as the angle between the inferior part of the glenoid fossa and the perpendicular to the floor of the supraspinatus, was compared with the global glenoid inclination (β angle or total shoulder arthroplasty [TSA] angle). Measurements were madeon plain anteroposterior radiographs and reformatted 2-dimensional (2D) computed tomography (CT) scans by 3 independent observers and compared with 3-dimensional (3D) software (Glenosys) measurements. The mean RSA angle was 25° ± 8° on plain radiographs, 20° ± 6° on reformatted 2D CT scans, and 21° ± 5° via 3D reconstruction software. The mean TSA angle was on average 10° ± 5° lower than the mean RSA angle (P < .001); this difference was observed regardless of the method of measurement (radiographs, 2D CT, or 3D CT)and type of glenoid erosion according to Favard. In Favard type E1 glenoids with central concentric erosion, the difference between the 2 angles was 12° ± 4° (P < .001). The same angle cannot be used to measure glenoid inclination in anatomic and reverse prostheses. The TSA (or β) angle underestimates the superior orientation of the reverse baseplate in RSA. The RSA angle (20° ± 5°) needs to be corrected to achieve neutral inclination of the baseplate (RSA angle = 0°). Surgeons should be aware that E1 glenoids (with central erosion) are at risk for baseplate superior tilt if the RSA angle is not corrected.

A technique for humeral prosthesis placement in reverse total shoulder arthroplasty for fracture.

Recent trends have illustrated the benefits of treating displaced fractures of the proximal humerus with reverse total shoulder arthroplasty. Clinical results have demonstrated reliable restoration of function in situations where results following hemiarthroplasty have been variable and difficult to predict. Data have demonstrated landmarks to assist with humeral stem height in hemiarthroplasty. However, intraoperative landmarks to guide placement of the humeral component in reverse shoulder arthroplasty have not been described. In this technique, the superior border of the pectoralis tendon is utilized. A distance of 5.0 cm is used to assist in placement of the most superior aspect of the metallic humeral component and with humeral stem version. This technique can be used as a guide to assist a treating physician in situations where bony fracture and comminution make humeral stem height placement difficult to judge.

Accuracy of patient-specific guided implantation of the glenoid component in reversed shoulder arthroplasty.

The aim of this study was to assess the accuracy of patient-specific guided glenoid component implantation in reverse shoulder arthroplasty. 32 reverse shoulder arthroplasties were done using preoperative 3D planning and 4 patient-specific guides to prepare the glenoid and position the glenoid component. Baseplate version, inclination and entry point as well as angulation of the screws were compared to the preoperative plan measured on CT by independent observers. The mean deviation in baseplate version from the preoperative plan was 4.4°+3.1° (range, 0.3°-13.7°), in baseplate inclination 5.0°+4.2° (range, 0.1° to 14.5°) and in baseplate entry point 2.4mm+1.4mm (range, 0.4° to 6.3°). The average screw superior-inferior angulation deviation for the superior screw was 2.8°+2.6° (range, 0.0°-10.1°) and 2.8+2.6° in the antero-posterior plane (range, 0.1°-11.6°). For the inferior screw the superior-inferior angle deviation was 5.3°+3.8° (range, 0.1°-15.2°); the antero-posterior angle deviation was 4.1°+3.1° (range, 0.0°-9.8°). Patient-specific instrumentation (PSI) for the glenoid component in reverse shoulder arthroplasty allows the shoulder surgeon to accurately execute the preoperative 3D plan. Level 3.

Reverse shoulder arthroplasty: Current trend in elective surgery

While reverse shoulder arthroplasty (RSA) is not generally accepted as a successful procedure until recent years, the concept of RSA has long been proposed. Several RSA designs were originally developed for treatment of cuff tear arthropathy (CTA) in the 1970’s, which all underwent in failure. From 1987 to 1995, Paul Grammont and his team proposed successful modern reverse designs of total shoulder arthroplasty for CTA. Medializing and distalizing the center of rotation are the most distinguished principles of Grammont’s RSA. The use of RSA has been increased dramatically over the past decades. The indications for RSA have expanded to massive irrepairable rotator cuff tears, proximal humerus fractures, fracture sequelae, inflammatory arthropathy, osteoarthritis with abnormal glenoid morphology, revision cases following failed shoulder arthroplasty, and tumor reconstruction, in addition to CTA. Contraindications to RSA includes infection, complete axillary nerve palsy, neuroarthropathy, and substantial glenoid bone erosion or defects. The number of complications and reoperations of RSA has been increased significantly with the wide application of RSA. RSA complications can be classified into non-specific complications, specific complications associated with RSA and brand-related specific problems. Glenoid bone loss is not uncommon in patients undergoing RSA, which is a challenging problem. Current methods for addressing glenoid bone loss during RSA include asymmetric reaming, use of a lateralized implant, bone grafting, and use of an augmented baseplate. Three-dimensional imaging preoperative planning software and patient-specific instruments have become commercially available for guidance in the insertion of the glenoid component in RSA in recent years. Surgeons performing RSA should select proper patients, be familiar with new surgical techniques and pay attention to technical details, so that the currently high complication rate of RSA can be reduced.

Planification préopératoire du positionnement de l’implant glénoïdien d’une prothèse d’épaule inversée – comparaison d’une méthode 3D interactive et d’une méthode traditionnelle

Introduction Glenoid component positioning during reverse shoulder arthroplasty (RSA) remains challenging. Patient-specific instrumentation (PSI) has been advocated to manage this technical pitfall. The purpose of this study was to determine the accuracy of glenoid placement when only the face of the glenoid is visible, and compare it to the accuracy when the entire scapula is visible on a 3D virtual model. Materials and methods Computed tomographies (CT's) of 30 pathologic shoulders were reconstructed into 3D models. Two surgeons then virtually placed a glenosphere component into the model while only visualizing the face of the glenoid in order to simulate the exposure typically seen intraoperatively (“blinded-3D” surgery). One surgeon then placed the component in an ideal position while visualizing the entire scapula (“full-3D visible” surgery). These two positions were then compared, and the accuracy of glenoid component positioning was determined by correction of the native glenoid version and tilt, as well as by the avoidance of glenoid vault perforation. Results The mean preoperative glenoid version and tilt were +5.4° A 9.9° and +10.7° A 9.5°, respectively. The mean version and tilt after “blinded-3D” surgery were +1.4° A 8.8° and +7.6° A 6°. Glenoid vault violation occurred in 17 specimens. The mean version and tilt after “full-3D-visible” surgery were +0.3° A 0.8° and +0.1° A 0.5°, with glenoid vault perforation in 6 cases. Results between the both surgeries were significantly different ( P P > 0.05). Discussion/conclusion Surgical accuracy of the glenoid component in RSA is compromised when only the face of the glenoid is available for reference as is typical during surgery. When the entire scapula is used as a reference, accuracy is improved and glenoid vault perforation is limited. This type of visualization is only possible with preoperative 3D-CT planning and may be augmented with PSI.

Reverse shoulder arthroplasty with a short metaphyseal humeral stem

Reverse shoulder prostheses have been gaining popularity in recent years. A short metaphyseal stem design will allow bone stock preservation and minimize stem related complications. We examined the clinical and radiographic short-term outcome of a short metaphyseal stem reverse shoulder arthroplasty. Thirty-one patients, with a mean follow-up of 36 months (24-52), were evaluated clinically with the Constant-Murley score, patient satisfaction and pain relief scores. The fixation of the glenoid and humeral components, subsidence and notching were evaluated on radiographs. The indications were cuff tear arthropathy (22), fracture sequelae (five) and rheumatoid arthritis (four). The average Constant score improved from 12.7 (range two to 31) pre-operatively to 56.2 (range 17-86) postoperatively. It rose from 13.5 to 58.3 in patients with Cuff arthropathy, from 15.8 to 62.0 in revision arthroplasty, from 10.2 to 47.4 in those with fracture sequelae, and from 11.5 to 55.3 in patients with rheumatoid arthritis. The overall mean patient satisfaction score improved from 2.4/10 to 8.5/10 and mean pain score improved from 0.8/15 to 12.5/15. We found an overall improvement in active forward flexion from 46.8 to 128.5° and from 41.6 to 116.5° in abduction. No humeral loosening or subsidence was observed. Two cases of grade 1-2 glenoid notching were reported. Overall there were three intra-operative fractures that did not affect the operation and healed without affecting the good results. There were five late traumatic periprosthetic fractures, only one of them required a revision surgery to a stemmed implant and the rest healed without surgery. There were two early dislocations that had to be revised. The clinical and radiographic evaluation of a bone preserving metaphyseal humeral component in reverse shoulder arthroplasty is promising, with good clinical results, no signs of loosening or subsidence.

Optimal glenoid component inclination in reverse shoulder arthroplasty. How to improve implant stability

The purpose of this study is to demonstrate that inferior inclination of the glenosphere is a protecting factor from joint dislocation in reverse total shoulder replacement. The hypothesis is that an average of 10° of inferior inclination of the glenoid component would determine a significant inferior rate of dislocation as compared to neutral inclination. A retrospective case (dislocation)-control (stability of the implant) study was performed. Inclusion criteria were the homogeneity of the prosthetic model and availability of pre- and postoperative imaging of the shoulder, including antero-posterior and axillary X-ray views. Glenoid and glenosphere inclination were calculated according to standardized methods. Difference in between the angles determined the inferior tilt. Thirty-three cases fit the inclusion criteria. Glenoid and glenosphere inclination measured, respectively, 74.1° and 83.5°. The average tilt of the glenosphere measured 9.4°. The average tilt in stable patients was 10.2°. Tilt in patients with atraumatic dislocation measured, respectively, -6.9° (superior tilt) and 2.4°, while it was 8.3° for the patient with traumatic instability. The association between the tilt of glenosphere and atraumatic dislocation was significant. A 10° inferior tilt of the glenoid component in reverse shoulder arthroplasty is associated with a reduced risk of dislocation when compared to neutral tilt.

Intraoperative CT navigation for glenoid component fixation in reverse shoulder arthroplasty

CT navigation has been shown to improve component positioning in total shoulder arthroplasty. The technique can be useful in achieving strong initial fixation of the metal backed glenoid in reverse shoulder arthroplasty. We report a 61 years male patient who underwent reverse shoulder arthroplasty for rotator cuff arthropathy. CT navigation was used intraoperatively to identify best possible glenoid bone and to maximize the depth of the fixation screws that anchor the metaglene portion of the metal backed glenoid component. Satisfactory positioning of screws and component was achieved without any perforation or iatrogenic fracture in the scapula. CT navigation can help in maximizing the purchase of the fixation screws that dictate the initial stability of the glenoid component in reverse shoulder arthroplasty. The technique can be extended to improve glenoid component position [version and tilt] with the availability of appropriate software.