Humeral Inclination Research Articles

Tuberosity healing in reverse shoulder arthroplasty for proximal humerus fractures with a diaphyseal press-fit humeral stem

BackgroundReverse shoulder arthroplasty (RSA) is a viable option for proximal humerus fractures (PHFs) in the elderly, and cemented humeral fixation is the standard of care. This study evaluates the influence of a diaphyseal press-fit stem with a 142° humeral inclination on tuberosity healing (TH) and functional outcome in RSA for PHF. MethodsTwenty-three patients received an RSA for PHF by a single surgeon at one center over a 2-year period. The humeral stem design was intended for diaphyseal press fit with a 142° humeral inclination. The tuberosities were repaired for each patient with bone graft and a standard suture technique. Patients’ clinical and radiographic outcomes were collected with a minimum 12-month follow-up. ResultsNineteen of 23 patients (83%), with a mean age of 75 + years, were available for follow-up at an average of 14 months. Radiographic analysis showed 68% of patients had evidence of TH. Grade 1 scapular notching was found in 32% of patients. There was no implant loosening or subsidence noted. Average range of motion was 163° ± 15° degrees of forward flexion, 113° ± 24° of abduction, internal rotation to the waist, and an average external rotation of 7 ± 1.5 as measured by the Constant-Murley score. The average American Shoulder and Elbow Surgeons score was 81.8, and the average Constant-Murley score was 67.9. While not significant, those with TH trended toward better clinical outcomes. There was a 0% revision rate. ConclusionA press-fit stem designed for diaphyseal fixation provides consistent reliable results in RSA for PHF. A high percentage of TH was appreciated with a 142° humeral inclination, neutral glenosphere construct, and a standardized bone grafting, suture technique. TH is associated with improved patient outcomes.

Patient-specific instrumentation reduces deviations between planned and postosteotomy humeral retrotorsion and height in shoulder arthroplasty.

Patient-specific instrumentation (PSI) may potentially improve humeral osteotomy in shoulder arthroplasty. The purpose of this study was to compare the deviation between planned and postosteotomy humeral inclination, retrotorsion, and height in shoulder arthroplasty, using PSI vs. standard cutting guides (SCG). Twenty fresh-frozen cadaveric specimens were allocated to undergo humeral osteotomy using either PSI or SCG, such that the 2 groups have similar age, gender, and side. Preosteotomy computed tomography (CT) scan was performed and used for the 3-dimensional (3D) planning. The osteotomy procedure was performed using a PSI designed for each specimen or an SCG depending on the group. A postosteotomy CT scan was performed. The preosteotomy and postosteotomy 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postosteotomy inclination, retrotorsion, and height. Outliers were defined as cases with 1 or more of the following deviations: >5° inclination, >10° retrotorsion, and >3 mm height. The deviation and outliers in inclination, retrotorsion, and height were compared between the 2 groups. The deviations between planned and postosteotomy parameters were similar among the PSI and SCG groups for inclination (P=.260), whereas they were significantly greater in the SCG group for retrotorsion (P<.001) and height (P=.003). There were 8 outliers in the SCG group, compared with only 1 outlier in the PSI group (P=.005). Most outliers in the SCG group were due to deviation >10° in retrotorsion. After 3D planning, PSI had less deviation between planned and postosteotomy humeral retrotorsion and height, relative to SCG.

Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty.

While the incidence of reverse total shoulder arthroplasty (rTSA) is increasing constantly, newer implants with designs other than the classic Grammont geometry are gaining importance. More anatomic inclination angles and lateralization are supposed to have a positive impact on clinical results and complication rates. Presentation of midterm results therefore is important to support these assumptions. The aim of this study was to report the midterm clinical outcome of primary rTSA with an uncemented humeral short-stem prosthesis (USSP) with a humeral inclination angle of 145° and the analysis of different variables on the outcome. This is a retrospective study of all patients with primary rTSA using an USSP and a combined humeral inclination angle of 145° (Ascend™ flex, Stryker) with a minimum clinical follow-up of 2years. The implant combines a 132.5° inclination for the humeral stem with an additional 12.5° for the polyethylene inlay. Primary outcomes were patient-reported outcome measures: ASES score, simple shoulder test (SST) and subjective shoulder value (SSV). Secondary outcomes were complication and revision rates. We analyzed different variables: preoperatively gender, age, indication for surgery and status of rotator cuff. Also, the glenoid morphology was classified according to Walch and a proximal humerus cortical bone thickness measurement (CBT avg) of 6mm was used as a threshold for osteoporosis. Postoperatively, we analyzed different radiologic parameters: filling ratio, distalization and lateralization angles according to Boutsiadis. A total of 84 out of 99 (85%) patients with a mean FU of 46.7months (range 24-80months) could be included: 62 women and 22 men with a mean age of 74.7years. Mean ASES score significantly increased from 47 preoperatively to 85.8 at the last follow-up (p = 0.001). The postoperative SST reached an average of 65.3 and the mean SSV was 83%. None of the variable parameters analyzed could be identified as a risk factor for a lower outcome defined as a SSV < 70. Three patients (3.6%) had a complication: one incomplete lower plexus lesion, one dislocation and one major hematoma. Surgical revision was needed in two cases (2.4%). The midterm clinical outcome of primary reverse total shoulder arthroplasty (rTSA) with an uncemented humeral short stem and a humeral inclination angle of 145° showed good-to-excellent results with a low complication and revision rate independent from a wide range of pre- and postoperative variables. PROMs are comparable to those reported for anatomic TSA with a low complication rate, different to historical studies especially with the Grammont design. Treatment study, Level IV.

Lateralized vs. classic Grammont-style reverse shoulder arthroplasty for cuff deficiency Hamada stage 1-3: does the design make a difference?

Reverse shoulder arthroplasty (RSA) with a lateralized design is thought to improve outcomes. Our aim was to compare RSA with the classic Grammont prosthesis against a prosthesis with 135° inclination and a lateralized glenosphere for cuff-deficient shoulders. Patients with irreparable massive posterosuperior rotator cuff tear Hamada grade 1-3 underwent RSA and were documented prospectively up to 24 months postsurgery. Comparative RSA groups were "lateralized" (L), with 135° humeral inclination and 36+4-mm lateralized glenosphere (n = 44), and "Grammont" (G), with 155° humeral inclination and 36+2-mm eccentric glenosphere (n = 23). Range of motion including the Apley scratch test, abduction strength, Constant-Murley score (CS), and Shoulder Pain and Disability Index (SPADI) were assessed. Anteroposterior and axial radiographs were evaluated at 24 months, and additional measurements of scapular neck and glenoid anatomy, baseplate and glenosphere position, center of rotation, humeral offset, and lateralization and distalization shoulder angles were made. Linear regression and mixed models adjusted for sex differences and preoperative values were applied. Overall CS and SPADI outcomes were not significantly different between groups (P ≥ .654). For group L, external rotation remained stable up to the 2-year follow-up and was higher than for group G (P = .012 ); a greater proportion of group L patients could reach the lumbar vertebra 3 (L3) (70% vs. 48% in group G) (P = .26). Group G had a higher inferior glenosphere overhang (P = .020) and center of rotation (COR) medialization (P < .001), whereas group L had higher humeral offset (P < .001) and lateralization shoulder angle (P < .001) with a trend toward higher baseplate positioning (P = .045). The rate of scapular notching was 2.9 times higher for group G than group L (P = .001). RSA with 135° humeral inclination and a lateralized glenosphere shows similar outcome scores as the classic Grammont design but enables better preservation of external rotation and reduces the rate of scapular notching compared with the classic Grammont design in Hamada 1-3 patients with irreparable posterosuperior tears.

Reverse Shoulder Arthroplasty Humeral Lateralisation: A Systematic Review.

Different studies on reverse shoulder arthroplasty (RSA) have proposed changes to the humeral design to lateralise the humeral centre of rotation (COR), with humeral inclination to 135 or 145 from 155 degrees or to switch to onlay humeral trays from inlay design; with both having also been used in combination. There have been many studies and systematic reviews to show the difference in outcomes and complications to the variations in glenoid design but to date, there have been no systematic studies to compare different humeral inclinations for RSA implants.Searches using keywords were used in common medical search engines in a systematic fashion. The article was reviewed for the class of evidence and bias, summarised and compared in meta-analysis. Inclusion criteria included studies on adults with RSA that compared lateralised humeral implants to medialised.The search produced 349 articles; of these, we identified nine studies that met the inclusion criteria. Our review identified a total of 562 patients who had been included in studies directly comparing lateralised humerus to a more medial design. Meta-analysis showed a significantly reduced risk of scapular notching in lateralised humerus compared to the standard medialised component. The external rotation range of motion in the lateralised group was statistically significant.The improvement in scapular notching and gain in the range of motion without any apparent downside in the form of reduced patient-reported outcome measures or complications suggest a lateralised humeral component is superior to the more medialised design in RSA. A large RCT with a longer-term follow-up is needed to confirm whether there is clinically significant benefit from the lateralisation of the humerus.

Reverse total shoulder arthroplasty with a humeral inclination of 135º for treatment of 3- and 4-part proximal humeral fractures: Clinical analysis with minimum follow-up of 2 years

Background: The reverse shoulder arthroplasty (RSA) is indicated for the treatment of proximal humerus fractures (PUF). To present day, there are limited data regarding the difference in functional outcomes of the RSA with a humeral inclination of 135º or 155º, in fracture context. The purpose of this study is to retrospectively analyze the functional outcomes of complex PUF treated with RSA with a humeral inclination of 135º. Materials and Methods: We carried out a retrospective study in which we analyzed 22 patients with PUF, who underwent RSA with a humeral inclination of 135º, between January 2017 and June 2019. Functional outcomes were measured through the Q-DASH and ASES scores. The Constant-Murley score (CS), active elevation (AA), abduction (ABD), internal rotation (IR), external rotation (ER), and abduction strength were obtained in both arms, using the contralateral shoulder as an estimative of preinjury function. Results: The patients were followed for a mean of 39.5 months. Seven patients were pain-free while performing their daily activities. Thirteen referred minor pain in their usual activities and 2 reported moderate to very severe pain. The mean ASES and Quick-DASH scores were 80% and 18.1 points, respectively. The CS was 59 points, 13 points less than the nonoperated side. The average AA was 128º, ABD 123º, ER 27º, and IR 36º. We found no correlation between the age and ASES score or Q-DASH score and between ER and ASES or Q-DASH score, but we found a positive correlation between ASES score or Q-DASH score and AA, ABD and IR. Conclusion: RSA is a valid and reliable option in selected elderly patients with complex PUF. The choice of the RSA humeral inclination (135º Vs 155º) does not currently have defined criteria, and there are no studies with sufficient statistical power to validate one of these options.

Mechanical complications and fractures after reverse shoulder arthroplasty related to different design types and their rates: part I.

The initial reverse shoulder arthroplasty (RSA), designed by Paul Grammont, was intended to treat rotator cuff tear arthropathy in elderly patients. In the early experience, high complication rates (up to 24%) and revision rates (up to 50%) were reported.The most common complications reported were scapular notching, whereas clinically more relevant complications such as instability and acromial fractures were less commonly described.Zumstein et al defined a ‘complication’ following RSA as any intraoperative or postoperative event that was likely to have a negative influence on the patient’s final outcome.High rates of complications related to the Grammont RSA design led to development of non-Grammont designs, with 135 or 145 degrees of humeral inclination, multiple options for glenosphere size and eccentricity, improved baseplate fixation which facilitated glenoid-sided lateralization, and the option of humeral-sided lateralization.Improved implant characteristics combined with surgeon experience led to a dramatic fall in the majority of complications. However, we still lack a suitable solution for several complications, such as acromial stress fracture. Cite this article: EFORT Open Rev 2021;6:1097-1108. DOI: 10.1302/2058-5241.6.210039

Effect of reverse total shoulder arthroplasty humeral inclination on glenohumeral range of motion, deltoid force, and glenoid strain: a biomechanical study

BackgroundReverse total shoulder arthroplasty (RSA) primarily varies between 2 implant design options: a 135 humeral stem inclination that closely resembles anatomic orientation, versus the Grammont-style 155 humeral stem inclination that further medializes and distalizes the center of rotation (COR). The purpose of this study was to compare deltoid force, glenoid strain, and simulated glenohumeral range of motion (ROM) between RSA 135 and RSA 155 designs, with a series of standardized permutations of glenosphere offset and rotator cuff pathology. MethodsTwelve fresh-frozen cadaveric shoulder specimens were studied using a shoulder simulator. Native shoulder motion profiles for reproducible abduction range of motion were established using a customized testing device. Optical 3-dimensional tracking and pressure sensors were used to accurately record glenohumeral range of motion (ROM), deltoid force, and glenoid strain for RSA 135 and RSA 155 designs. For each cohort, all combinations of glenosphere offsets and rotator cuff tendon involvement were evaluated. ResultsThere was no significant difference in the overall abduction ROM between the 155 and the 135 humeral stem implants (P = .75). Resting abduction angle and maximum abduction angle were significantly greater with a 155 + STD (standard offset) construct than with a 135 + STD construct (P < .001 and P = .01, respectively). Both stem inclinations decreased combined deltoid force requirements as compared the native shoulder with a massive cuff tear. Effective glenoid strain did not vary significantly between 135 + STD and 155 + STD constructs (P = .66). ConclusionOverall, range of motion between the 135 and the 155 humeral stem inclinations was not significantly different. The cumulative deltoid force was lower in RSA shoulders when compared to native shoulders with massive rotator cuff tears, highlighting the utility of both implant designs. The Grammont-style 155 stem coupled with a 2.5 mm inferior offset glenosphere required less deltoid force to reach maximum abduction than did the more anatomic, lateralized 135 stem coupled with a 4 mm lateral offset glenosphere. Level of EvidenceBasic Science, Biomechanics Controlled Laboratory Study

Clinical and Radiological Outcomes in Reverse Total Shoulder Arthroplasty by Inclination Angle With a Modular Prosthesis.

The influence of the humeral inclination in reverse total shoulder arthroplasty (RTSA) is not well understood. The purpose of this study was to determine outcomes and complications after RTSA with an inclination of 135° or 155° in a modular prosthesis. American Shoulder and Elbow Surgeons (ASES), visual analog scale (VAS), Single Assessment Numeric Evaluation (SANE), and Simple Shoulder Test (SST) scores, as well as forward elevation (FE), abduction (ABD), and external rotation (ER), were assessed after a minimum 2-year follow-up. Scapular notching and radiolucency were assessed according to Sirveaux and Lévigne. A total of 121 patients with a mean age of 69.7±7.3 years were evaluated after a mean of 36.5±8 months. The inclination was set to 135° in 80.2% and to 155° in 19.8% of patients. There was no significant difference between the groups for ASES, VAS, SANE, and SST scores. The FE (P=.022) and ABD (P=.002) were significantly higher for the 155° inclination group. Complication rates were not significantly different between the groups. Scapular notching was significantly more common with a 155° inclination (P=.01), whereas humeral radiolucency was not correlated. All outcome scores improved significantly from pre- to postoperative (P≤.001). Reverse total shoulder arthroplasty leads to significant improvements in pain, range of motion, and outcome scores after mid-term follow-up. Overall, the inclination angle does not significantly affect clinical outcomes or the complication rate after RTSA at mid-term follow-up. However, an inclination of 155° shows significantly greater FE and ABD, although it results in a significantly higher rate of scapular notching. Cases with scapular notching are associated with significantly reduced mean ASES scores and ER as well as significantly higher VAS scores. [Orthopedics. 2021;44(4):e527-e533.].

Treating cuff tear arthropathy by reverse total shoulder arthroplasty: do the inclination of the humeral component and the lateral offset of the glenosphere influence the clinical and the radiological outcome?

Reverse total shoulder arthroplasty is widely used for the treatment of cuff tear arthropathy. Standard implants consist of a humeral component with an inclination angle of 155° and a glenosphere without lateral offset. Recently, lower inclination angles of the humeral component as well as lateralized glenospheres are implanted to provide better rotation of the arm and to decrease the rate of scapular notching. This study investigates the clinical and radiological results of a standard reverse total shoulder in comparison with an implant with an inclination angle of 135° in combination with a 4mm lateralized glenosphere in context of cuff tear arthropathy. For this retrospective comparative analysis 42 patients treated by reverse total shoulder arthroplasty for cuff tear arthropathy were included. Twenty-one patients (m = 11, f = 10; mean age 76years; mean follow-up 42months) were treated with a standard 155° humeral component and a standard glenosphere with caudal eccentricity (group A), while twenty-one patients (m = 5, f = 16; mean age 72years; mean follow-up 34months) were treated with a 135° humeral component and 4mm lateral offset of the glenosphere (group B). At follow-up patients of both groups were assessed with plain X-rays (a.p. and axial view), Constant Score, adjusted Constant Score, the subjective shoulder value and the range of motion. The clinical results were similar in both groups concerning the Constant Score (group A = 56.3 vs. group B = 56.1; p = 0.733), the adjusted CS (group A = 70.4% vs. group B = 68.3%; p = 0.589) and the SSV (group A = 72.0% vs. group B = 75.2%; p = 0.947). The range of motion of the operated shoulders did not differ significantly between group A and group B: Abduction = 98° versus 97.9°, p = 0.655; external rotation with the arm at side = 17.9° versus 18.7°, p = 0.703; external rotation with the arm positioned in 90° of abduction = 22.3° versus 24.7°, p = 0.524; forward flexion = 116.1° versus 116.7°, p = 0.760. The rate of scapular notching was higher (p = 0.013) in group A (overall: 66%, grade 1: 29%, grade 2: 29%, grade 3: 10%, grade 4: 0%) in comparison to group B (overall: 33%, grade 1: 33%, grade 2: 0%, grade 3: 0%, grade 4: 0%). Radiolucency around the humeral component was detected in two patients of group B. Stress shielding at the proximal humerus was observed in six patients of Group A (29%; cortical thinning and osteopenia in zone M1 and L1) and two patients of group B (10%; cortical thinning and osteopenia in zone M1 and L1). Calcifications of the triceps origin were observed in both groups (group A = 48% vs. group B = 38%). Theoretically, a lower inclination angle of the humeral component and an increased lateral offset of the glenosphere lead to improved impingement-free range of motion and a decreased rate of scapular notching, when compared to a standard reverse total shoulder implant. This study compared two different designs of numerous options concerning the humeral component and the glenosphere. In comparison to a standard-fashioned implant with a humeral inclination of 155° and a standard glenosphere, implants with a humeral inclination angle of 135° and a 4mm lateralized glenosphere lead to comparable clinical results and rotatory function, while the rate of scapular notching is decreased by almost 50%. While the different implant designs did not affect the clinical outcome, our results indicate that a combination of a lower inclination angle of the humeral component and lateralized glenosphere should be favored to reduce scapular notching. Level III, retrospective comparative study.

Higher primary stability of tuberosity fixation in reverse fracture arthroplasty with 135° than with 155° humeral inclination

Proximal humeral fractures in elderly patients are frequently treated with reverse total shoulder arthroplasty, and tuberosity healing improves clinical outcome and patient satisfaction. So far reverse prostheses with different humeral inclination (HI) angles have been used. However, it has not been investigated yet if the HI angle affects the primary stability of the tuberosity fixation in primary reverse total shoulder arthroplasty for proximal humeral fractures in a biomechanical setting. A 4-part fracture was created in 7-paired human cadaver proximal humeri after preceding power analysis. After randomization in a pairwise fashion, reverse prostheses with either 135° (n = 7) or 155° (n = 7) were implanted. The tuberosities were reduced anatomically to the metaphysis of the prostheses and were fixed with 3 suture cerclages in a standardized technique. Tightening was performed with a cerclage tension device with 50 Newton meter (N m). Before biomechanical testing, the initial vertical and horizontal gap formation was measured. The humeri were placed in a custom-made test setup enabling internal and external rotation. Cyclic loading with a gradually increasing load magnitude was applied with a material testing machine starting with 20 N m and increasing by 5 N m after each 100th cycle until failure (>15° rotation of the tuberosities). Any motion of the tuberosities was measured with a 3-dimensional camera system. Overall, the 155° group reached an average of 1460 ± 270 cycles and the 135° group of 1900 ± 271 cycles (P = .048). In contrast to the 135° group, in the 155° group, a mean initial vertical (0.3 ± 0.7 mm) and horizontal (2.7 ± 3.3 mm) gap formation could be observed before cyclic loading. After 1100 cycles, the 155° group showed increased rotation of both lesser and greater tuberosities in all 3 axes around the humeral shaft compared with the 135° group. Primary stability of the reattached tuberosities is significantly increased, whereas rotational movements are decreased in prostheses with an anatomic HI of 135° compared with a 155° HI according to the original Grammont design. In addition, a 135° HI allows an exact anatomic reposition of the tuberosities, whereas this was not possible for the 155° design. However, transferability and clinical relevance of these biomechanical results have to be verified with clinical studies.

Anatomic factors influencing the anterior stability of reverse total shoulder arthroplasty

Several factors affect the stability of the reverse shoulder arthroplasty. The influence of bony anatomy on anterior stability remains unclear. This study aimed to identify the correlations between bony anatomy and anterior dislocation forces. The differences in anterior dislocation force in reverse total shoulder arthroplasty reported in a previous biomechanical study were used to analyze the anatomic factors influencing anterior stability. The critical shoulder angle, glenocoracoid distance in 2 planes, and glenoid inclination were measured in the tested specimens using 3-dimensional computed tomographic scans and radiographs. Anatomic parameters were then correlated with the anterior dislocation forces. The critical shoulder angle had no correlation with anterior stability. The glenocoracoid distance in anteroposterior direction showed a negative correlation with the stability of a reverse shoulder arthroplasty with a 9-mm lateralized glenosphere and 155° humeral inclination in 30° and 60° glenohumeral abduction with the arm in 30° external rotation (r = -0.662, P = .004; r = -0.794, P = .011) and 30° glenohumeral abduction with neutral rotation (r = -0.614, P = .009). Using the same hardware configuration, the anterior stability had a negative correlation with the glenocoracoid distance in the mediolateral direction in 30° of glenohumeral abduction with the arm in 0° and 30° of external rotation (r = -0.542, P = .025; r = -0.497, P = .042). The distance between the coracoid tip and glenoid in 2 planes had a significant negative correlation with the anterior stability of the reverse shoulder arthroplasty with a lateralized glenosphere and 155° humeral inclination. The findings suggest that only glenoid lateralization is influenced by the bony anatomy.

Tuberosity healing improves functional outcome following primary reverse shoulder arthroplasty for proximal humeral fractures with a 135° prosthesis.

Reverse shoulder arthroplasty (RSA) is a common treatment for proximal humeral fractures (PHFs) in the elderly. This study evaluates the influence of tuberosity healing (TH) on functional outcome following a 135° humeral inclination RSA for PHFs. Retrospectively, all patients with an acute PHF treated with a 135° humeral inclination RSA at four centers during a three-year period were followed up. Constant score (CS), TH and glenoid notching were analyzed. Sixty-four of 100 patients (64%) with a mean age of 76 ± 7years were available for follow-up at 22 ± 8months. The mean-adjusted CS was 72%. TH of the greater tuberosity (GT) was 77% and resulted in significantly improved forward flexion (128° vs. 92°; p = 0.003), external rotation (33° vs. 17°; p = 0.03) and adjusted CS (78% vs. 54%, p < 0.005). GT healing rate was 86% with neutral, 70% with lateralized and 33% with an inferior eccentric glenosphere. TH of the lesser tuberosity was 79%. There was 8% complication and 3% revision rate; implant survival was 100%. RSA with 135° humeral inclination for PHFs leads to good functional outcome, reproducible results and a high rate of TH. The short-term revision rate is low. TH is associated with improved ROM and functional outcome. III.

High tuberosity healing rate associated with better functional outcome following primary reverse shoulder arthroplasty for proximal humeral fractures with a 135\xb0 prosthesis

BackgroundReverse shoulder arthroplasty (RSA) is a common treatment for proximal humeral fractures. (PHF) in the elderly. This study evaluates the functional outcome and the influence of. tuberosity healing (TH) following RSA with 135° humeral inclination and a neutral glenosphere without lateralization for PHFs.MethodsIn this retrospective case series, all patients with an acute PHF treated with primary RSA with 135° humeral inclination and a standard glenosphere without lateralization during a four-year period were followed up. Constant score (CS), patient satisfaction (subjective shoulder value (SSV)), TH and glenoid notching were analyzed.Results38 patients with a mean age of 77 ± 8 years were available for follow-up at 34 ± 5 months. The mean adjusted CS was 61 ± 9 points. TH of the greater tuberosity (GT) was 82% and resulted in significantly improved abduction (117° vs. 81°; P < 0.001), forward flexion (139° vs. 99°; p < 0.001), external rotation (28° vs. 10°; p = 0.002), CS (65 vs. 41 points; p < 0.001) and patient satisfaction (SSV 79% vs. 48%; p < 0.001). TH of the LT was 87% without affecting internal rotation or overall outcome. The complication- and revision rate was 5%; implant survival was 100%. Scapular notching occurred in 3 (8%) cases (all grade 1).ConclusionRSA with 135° humeral inclination and a standard glenosphere for PHF leads to good functional outcome in combination with a high rate of TH and a low rate of scapular notching. The short-term revision rate is low and the results are predictable and continuous. TH is associated with improved ROM, patient satisfaction and functional outcome.

Determination of humeral inclination in stemless shoulder arthroplasty using plain radiographs

Plain radiographs of the shoulder are routinely used to assess implant orientation after shoulder arthroplasty. Recently, humeral inclination has come into focus especially in reverse stemless shoulder arthroplasty. But, in X-ray projections not exactly parallel to the base of the humeral component, the humeral inclination angle cannot be determined precisely. Therefore, we established a mathematical algorithm to calculate the humeral neck shaft angle and counterchecked the formula using plain radiographs of a sawbone model containing a humeral head prosthesis. With increasing angles of retroversion, the base of the humeral component forms an ellipse in plain radiographs. 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. Thus, independent from the viewing angle or angle of retroversion, the inclination angle of a stemless humeral head implant can be estimated with an accuracy of ±1.5-degree deviation. The algorithm proposed may be the basis for further research on the impact of humeral inclination in stemless shoulder arthroplasty.

Effect of Critical Shoulder Angle, Glenoid Lateralization and Humeral Inclination on Range of Motion in Reverse Shoulder Arthroplasty

Effect of Critical Shoulder Angle, Glenoid Lateralization and Humeral Inclination on Range of Motion in Reverse Shoulder Arthroplasty

Effect of critical shoulder angle, glenoid lateralization, and humeral inclination on range of movement in reverse shoulder arthroplasty.

ObjectivesTo date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies.Methods3D computer models were constructed from CT scans of 12 patients with a critical shoulder angle (CSA) of 25°, 30°, 35°, and 40°. For each model, shoulder ROM was evaluated at a NSA of 135° and 145°, and lateralization of 0 mm, 5 mm, and 10 mm for seven standardized movements: glenohumeral abduction, adduction, forward flexion, extension, internal rotation with the arm at 90° of abduction, as well as external rotation with the arm at 10° and 90° of abduction.ResultsCSA did not seem to influence ROM in any of the models, but greater lateralization achieved greater ROM for all movements in all configurations. Internal and external rotation at 90° of abduction were impossible in most configurations, except in models with a CSA of 25°.ConclusionPostoperative ROM following RSA depends on multiple patient and surgical factors. This study, based on computer simulation, suggests that CSA has no influence on ROM after RSA, while lateralization increases ROM in all configurations. Furthermore, increasing subacromial space is important to grant sufficient rotation at 90° of abduction. In summary, increased lateralization of the COR and increased subacromial space improve ROM in all CSA configurations.Cite this article: A. Lädermann, E. Tay, P. Collin, S. Piotton, C-H Chiu, A. Michelet, C. Charbonnier. Effect of critical shoulder angle, glenoid lateralization, and humeral inclination on range of movement in reverse shoulder arthroplasty. Bone Joint Res 2019;8:378–386. DOI: 10.1302/2046-3758.88.BJR-2018-0293.R1.

Can a functional difference be detected in reverse arthroplasty with 135° versus 155° prosthesis for the treatment of rotator cuff arthropathy: a prospective randomized study

The purpose of this randomized controlled trial was to compare humeral inclinations of 135° and 155° in patients undergoing primary reverse shoulder arthroplasty (RSA). Our hypothesis was that forward flexion would be higher in the 155° group but be associated with a higher rate of scapular notching. A randomized controlled trial was conducted on 100 primary RSAs performed with a humeral inclination of either 135° or 155°. The prostheses were otherwise identical and a neutral glenosphere was used in all cases. Functional outcome, forward flexion, external rotation, and scapular notching were assessed at a minimum of 2 years postoperatively. There was no difference in range of motion or functional outcome scores between the 2 groups. In the 155° group, forward flexion improved from 76° to 135° (P < .001) and external rotation remained unchanged (29° vs. 30°; P = .835). In the 135° group, postoperative forward flexion improved from 78° to 132° (P < .001) and external rotation was unchanged (28° vs. 29°; P = .814). Scapular notching was observed in 58% of cases with a 155° inclination compared with 21% with a 135° inclination (P = .009). With a neutral glenosphere there was no difference in postoperative forward flexion or external rotation after an RSA with a humeral inclination of 135° compared with 155°. Scapular notching was reduced with the use of 135° design compared with a 155° design but persists at a rate of 21% at 2-year follow-up in the absence of a lateralized glenosphere.

Anatomic humeral head replacement with a press-fit prosthesis: An in vivo radiographic study.

Successful total shoulder arthroplasty is, in part, dependent on anatomic reconstruction of the glenohumeral joint. The purpose of this study was to evaluate the post-operative anatomy of total shoulder arthroplasty with an anatomic implant design in patients with primary glenohumeral osteoarthritis and compare it to published normative anatomic measurements. Fifty-one patients (56 shoulders) with primary glenohumeral osteoarthritis were treated with a press-fit humeral component as part of a total shoulder arthroplasty (Aequalis, Tornier, Edina, Minnesota). Analysis of postoperative true anterior posterior radiographs was performed with use of a custom software algorithm. The mean humeral inclination (head-shaft angle), mean humeral implant anatomical humeral axis, mean greater tuberosity height, and mean humeral head center offset (medial offset) were 135.4±5.1°, 1.73±1.7°, 6.9±2.4 mm, and 3.8±1.8 mm, respectively. All parameters were within the ranges reported in the literature for normal shoulders except the mean humeral head center offset, which was less than reported in the literature. Anatomic parameters of a total shoulder arthroplasty can be achieved with an anatomically designed, modular adaptable press-fit design. Reduced medial humeral head center offset was likely dependent upon implant specific design parameters.

The influence of humeral neck shaft angle and glenoid lateralization on range of motion in reverse shoulder arthroplasty

Recent developments in reverse shoulder arthroplasty (RSA) have focused on changes in several design-related parameters, including humeral component design, to allow for easier convertibility. Alterations in humeral inclination and offset on shoulder kinematics may have a relevant influence on postoperative outcome. This study used a virtual computer simulation to evaluate the influence of humeral neck shaft angle and glenoid lateralization on range of motion in onlay design RSA. Three-dimensional RSA computer templating was created from computed tomography (CT) scans in 20 patients undergoing primary total shoulder arthroplasty for concentric osteoarthritis (Walch A1). Two concurrent factors were tested for impingement-free range of motion: humeral inclination (135° vs. 145°) and glenoid lateralization (0 mm vs. 5 mm). Decreasing the humeral neck shaft angle demonstrated a significant increase in impingement-free range of motion. Compared to the 145° configuration, extension was increased by 42.3° (-8.5° to 73.5°), adduction by 15° (10° to 23°), and external rotation with the arm at side by 15.1° (8.5° to 26.5°); however, abduction was decreased by 6.5° (-1° to 12.5°). Glenoid lateralization led to comparable results, but an additional increase in abduction of 7.6° (-1° to 16.5°) and forward flexion of 26.6° (6.5° to 62°) was observed. Lower humeral neck shaft angle and glenoid lateralization are effective for improvement in range of motion after RSA. The use of the 135° model with 5 mm of glenoid lateralization provided the best results in impingement-free range of motion, except for abduction.