Orthopedics

Feature Article 

Effect of Reverse Shoulder Arthroplasty Lateralization Design on Scapular Notching: A Single-Surgeon Experience

Bradley S. Schoch, MD; Houtan Taba, MD; William Aibinder, MD; Joseph J. King, MD; Thomas W. Wright, MD

Abstract

Scapular notching remains a concern with both medialized and lateralized reverse shoulder arthroplasty (RSA) designs. Few studies have directly compared the rate of notching among various designs. The purpose of this study was to compare a single surgeon's rate of scapular notching in relation to RSA design. A total of 156 primary RSAs were performed for cuff tear arthropathy or osteo-arthritis with rotator cuff insufficiency by a single surgeon. Follow-up was controlled to between 3 and 5 years. Shoulders were grouped according to implant design: medialized center of rotation (CoR; n=17), lateralized CoR (n=14), and lateralized humerus (n=125). Objective clinical outcomes, patient-reported outcomes, and radiographic outcomes were compared. Scapular notching occurred more frequently with medialized CoR (82%) and lateralized CoR (57%) designs compared with a lateralized humerus design (22%; P<.001). Mean notching grade was also lower in the lateralized humerus design (0.2) compared with the medialized CoR (2.1; P<.001) and lateralized CoR (1.1; P=.01) designs. Postoperative pain, range of motion, and patient-reported outcomes were not significantly different among groups. A low rate of reoperation was seen in all groups. The lateralized humeral RSA design showed less frequent and less severe scapular notching compared with medialized CoR and lateralized CoR designs. There were no observed differences in range of motion or patient-reported outcomes between different implant designs. [Orthopedics. 2020;43(6):e585–e591.]

Abstract

Scapular notching remains a concern with both medialized and lateralized reverse shoulder arthroplasty (RSA) designs. Few studies have directly compared the rate of notching among various designs. The purpose of this study was to compare a single surgeon's rate of scapular notching in relation to RSA design. A total of 156 primary RSAs were performed for cuff tear arthropathy or osteo-arthritis with rotator cuff insufficiency by a single surgeon. Follow-up was controlled to between 3 and 5 years. Shoulders were grouped according to implant design: medialized center of rotation (CoR; n=17), lateralized CoR (n=14), and lateralized humerus (n=125). Objective clinical outcomes, patient-reported outcomes, and radiographic outcomes were compared. Scapular notching occurred more frequently with medialized CoR (82%) and lateralized CoR (57%) designs compared with a lateralized humerus design (22%; P<.001). Mean notching grade was also lower in the lateralized humerus design (0.2) compared with the medialized CoR (2.1; P<.001) and lateralized CoR (1.1; P=.01) designs. Postoperative pain, range of motion, and patient-reported outcomes were not significantly different among groups. A low rate of reoperation was seen in all groups. The lateralized humeral RSA design showed less frequent and less severe scapular notching compared with medialized CoR and lateralized CoR designs. There were no observed differences in range of motion or patient-reported outcomes between different implant designs. [Orthopedics. 2020;43(6):e585–e591.]

The indications for reverse shoulder arthroplasty (RSA) continue to expand as survivorship of implanted components has demonstrated increasing longevity compared with anatomic designs. However, complication rates have been reported to be higher than anatomic shoulder arthroplasty.1 Since the introduction of the initial Grammont design, numerous modifications of the reverse prosthesis design have been implemented in an effort to decrease complications.2 Scapular notching remains a concern across both the medialized and lateralized center of rotation (CoR) designs. Over the long-term, notching can compromise glenoid baseplate stability and increase the risk of component loosening.3 Some authors have also noted poorer outcomes in shoulders with notching.4–6 Rates of scapular notching have been reported between 33% and 92% for Grammont-style designs.7,8 Similar series evaluating lateralized designs have reported lower incidences of notching (between 0% and 29%).9,10

Multiple basic science studies have evaluated the implication of the neck-shaft angle and glenoid design characteristics on the rates of notching.11–13 However, few clinical studies have directly evaluated the effect of prosthetic design on notching in vivo among different designs. Kowalsky et al8 compared 2 RSA designs with differing humeral inlay geometry. The use of a varying thickness inlay polyethylene led to a 63% decrease in notching at early follow-up.8 This study remains limited by the fact that both implants were Grammont-style designs with inset humeral components. Currently, no published studies directly compare the rates of notching for medialized and lateralized RSA designs.

The primary objective of this study was to compare the rate of scapular notching in a single surgeon's experience using multiple RSA prosthesis designs. Secondary outcomes included clinical outcomes, patient-reported outcomes (PROs), and reoperation.

Materials and Methods

Between June 2004 and July 2014, a total of 146 patients (157 shoulders) underwent primary RSA by a single surgeon (T.W.W.) for a diagnosis of cuff tear arthropathy or osteoarthritis with rotator cuff insufficiency. Patient records were retrospectively reviewed from a prospectively collected database following institutional review board approval. All shoulders were treated using a deltopectoral approach. Given the time span of the study, follow-up was controlled and evaluated only between 3 and 5 years after primary arthroplasty. One shoulder was eliminated due to insufficient radiographs. The remaining 156 RSAs were evaluated at a mean follow-up of 4.1 years (range, 3–5 years).

Shoulders were grouped based on implant design: medialized CoR with an inlay humerus (Grammont), lateralized CoR glenoid with an inlay humerus (lateralized glenosphere), and medialized CoR with an onlay humerus (lateralized humerus; Figure 1).14,15 During the study period, the senior surgeon (T.W.W.) changed the primary implant design twice. Initially, Grammont-style implants were used: Aequalis (Tornier, Minneapolis, Minnesota; June 2004 to May 2006, n=13) and Delta III (DePuy, Warsaw, Indiana; October 2005 to August 2006, n=4). Between September 2005 and January 2011, the Encore (DJO, Vista, California) lateralized CoR glenoid design was used (n=14). Starting in May 2007, the primary RSA implant used was the Equinoxe (n=125; Exactech, Gainesville, Florida) with a lateralized humerus design. Demographic data for each group are presented in Table 1.

Grammont prosthesis showing a glenosphere with the center of rotation at the glenoid face with minimal humeral offset (left). The lateralized glenosphere component demonstrates the glenosphere center of rotation lateral to the face of the glenoid face with minimal humeral offset (center). The lateralized humerus component demonstrates minimal offset of the glenosphere center of rotation from the glenoid face with lateralization of the humeral shaft from the scapula (right). [Reprinted with permission from Routman HD, Flurin PH, Wright TW, Zuckerman JD, Hamilton MA, Roche CP. Reverse shoulder arthroplasty prosthesis design classification system. Bull Hosp Jt Dis. 2015(suppl1):S5–S14.]

Figure 1:

Grammont prosthesis showing a glenosphere with the center of rotation at the glenoid face with minimal humeral offset (left). The lateralized glenosphere component demonstrates the glenosphere center of rotation lateral to the face of the glenoid face with minimal humeral offset (center). The lateralized humerus component demonstrates minimal offset of the glenosphere center of rotation from the glenoid face with lateralization of the humeral shaft from the scapula (right). [Reprinted with permission from Routman HD, Flurin PH, Wright TW, Zuckerman JD, Hamilton MA, Roche CP. Reverse shoulder arthroplasty prosthesis design classification system. Bull Hosp Jt Dis. 2015(suppl1):S5–S14.]

Demographic Data for All Reverse Shoulder Arthroplasties by Implant Design

Table 1:

Demographic Data for All Reverse Shoulder Arthroplasties by Implant Design

Preoperative, immediate postoperative, and final postoperative radiographs were reviewed for all patients. Standardized Grashey and axillary lateral radiographs were routinely performed for all shoulders. Preoperative Grashey radiographs were used to measure the subacromial interval in millimeters. Preoperative glenoid inclination was assessed using both the scapular alpha angle as described by Bufquin et al16 and the scapular beta angle described by Maurer et al17 (Figure 2).

Preoperative anteroposterior radiograph showing alpha and beta angles.

Figure 2:

Preoperative anteroposterior radiograph showing alpha and beta angles.

Three orthopedic surgeons (B.S.S., H.T., J.J.K.) evaluated all postoperative radiographs to assess glenoid notching, which was graded according to Sirveaux et al18 (Figure 3). In cases of disagreement, a majority consensus was used as the recorded grade. The performing surgeon (T.W.W.) did not participate in radiographic evaluation. Additional radiographic outcome measures included acromiohumeral interval, scapular neck length, glenosphere overhang, alpha angle, beta angle, and humeral component lucent lines, as described by Sperling et al.20 Glenoid overhang was corrected for magnification based on the known size of the implanted glenosphere.

Immediate postoperative anteroposterior radiograph (A) of a lateralized humerus prosthesis compared with a 4.5-year postoperative antero-posterior radiograph (B) showing grade 2 notching (arrows).

Figure 3:

Immediate postoperative anteroposterior radiograph (A) of a lateralized humerus prosthesis compared with a 4.5-year postoperative antero-posterior radiograph (B) showing grade 2 notching (arrows).

Postoperative range of motion was assessed and compared among groups by implant design. All range of motion measures were independently assessed by a clinical research coordinator (A.M.S.). Forward elevation and external rotation were assessed in degrees using a goniometer. Internal rotation was determined by the level reached by the thumb behind the back. Pre- and postoperative PROs included Shoulder Pain and Disability Index, University of California Los Angeles shoulder score, American Shoulder and Elbow Surgeons score, the Constant score, the Short Form-12 score, and the Simple Shoulder Test score.

Statistical Analysis

A Kruskal–Wallis test was performed to assess the differences in preoperative clinical and radiographic parameters, as well as in postoperative clinical parameters and radiographic parameters. Statistical significance was set at P<.05. When a significant difference between the 3 groups was identified, a post hoc analysis was performed to further characterize the difference. A chi-square test was used to identify difference in the rate of notching present between different groups.

Results

A total of 156 primary RSAs were evaluated between 3 and 5 years postoperatively. Follow-up was similar among all groups (P=.7). Average body mass index was significantly lower for Grammont shoulders compared with both the lateralized glenosphere and lateralized humerus groups (P=.009; Table 1). The groups were otherwise similar regarding age, sex, and preoperative diagnosis.

Radiographic Outcomes

Preoperative radiographs demonstrated similar glenoid inclination among all groups as measured by the alpha and beta angles. The acromiohumeral interval was significantly lower in the lateralized glenosphere group compared with the lateralized humerus group (1.4 vs 4.1 mm, P=.005). The acromiohumeral interval was similar between the Grammont and lateralized humerus groups (P=.3). Full preoperative radiographic data are presented in Table 2.

Preoperative Radiographic Measures by Implant Design

Table 2:

Preoperative Radiographic Measures by Implant Design

Postoperative radiographic analysis showed no difference in glenoid tilt based on the alpha angle, as described by Bufquin et al.16 However, when assessing glenoid baseplate tilt using the method of Maurer et al,17 inferior tilt was significantly greater in the lateralized humerus group compared with the lateralized glenosphere group (beta angle, 82.3° vs 88.2°; P=.028). Inferior tilt was similar between Grammont components (beta angle, 84.4°) and both other groups. Glenosphere overhang was significantly greater in the lateralized humerus group (5.68 mm) compared with both the Grammont (−1.35 mm) and lateralized glenosphere (0.66 mm) groups (P<.001 and P=.001, respectively). Postoperative radiographic data are summarized in Table 3.

Postoperative Radiographic Measures by Implant Design

Table 3:

Postoperative Radiographic Measures by Implant Design

Scapular notching was observed significantly more frequently in the Grammont (82%) and lateralized glenosphere (57%) groups compared with the lateralized humerus group (22%; P<.001; Figure 4 and Figure 5). The rates of notching and grade are displayed in Table 3. Mean notching grade was lower in the lateralized humerus group (0.24) compared with the Grammont (2.06, P<.001) and lateralized glenosphere (1.07, P=.01) groups. No statistical difference was identified between the mean notching grade of Grammont and lateralized glenosphere desgins (P=.15). Humeral radiolucent lines were similar among all groups (P=.8).

Early (A) and 4-year (B) postoperative anteroposterior radiographs demonstrating a lateralized glenosphere prosthesis with grade 2 notching (arrows).

Figure 4:

Early (A) and 4-year (B) postoperative anteroposterior radiographs demonstrating a lateralized glenosphere prosthesis with grade 2 notching (arrows).

Early (A) and 5-year (B) postoperative anteroposterior radiographs demonstrating a lateralized humerus prosthesis with no notching.

Figure 5:

Early (A) and 5-year (B) postoperative anteroposterior radiographs demonstrating a lateralized humerus prosthesis with no notching.

Clinical Outcomes

Postoperative pain, range of motion, and PROs were similar among all groups, regardless of implant design (Table 4). Three patients underwent revision or reoperation within the first 5 years of follow-up. One patient treated with a lateralized humerus RSA developed significant shoulder pain postoperatively that was associated with a sensation of prosthetic subluxation. Four years postoperatively, an evaluation under anesthesia was recommended with possible revision. Under initial fluoroscopic evaluation, the prosthesis was not able to be dislocated, but mechanical clicking was palpable. A revision was performed and excessive shuck was noted in the glenohumeral articulation. A modular exchange with a larger glenosphere and polyethylene exchange was performed.

Postoperative Patient-Reported Outcomes by Implant Design

Table 4:

Postoperative Patient-Reported Outcomes by Implant Design

Another patient treated with a Grammont RSA developed a loose glenoid baseplate. A revision was performed 3 years postoperatively, during which the implant was converted to a hemiarthroplasty due to deficient glenoid bone stock.

Finally, a third patient treated with a lateralized humerus RSA sustained a Wright/Cofield type B periprosthetic humeral shaft fracture 2 years postoperatively. Intraoperative assessment demonstrated a stable humeral implant, and the fracture was fixed primarily with retention of all arthroplasty components.

Discussion

Scapular notching remains a concern across RSA designs, with reported rates between 0% and 92%.7,8,19,21 Established risk factors for notching include a lower preoperative acromiohumeral interval, a lower body mass index, superior inclination of the glenoid, and less inferior glenosphere offset.7,22 Notching has previously been associated with poorer functional outcomes and implant loosening.5,21 Efforts to minimize notching have been evident with design advancements in RSA. However, reports comparing the rates of notching between implants remain limited.8 The current study reflects a single surgeon's experience with a variety of implant designs.

In the current study, scapular notching was seen more frequently in the Grammont (82%) and lateralized glenosphere (57%) groups compared with the lateralized humerus group (22%). The high rate of notching seen with the Grammont-style design is similar to other reports on this design.21 Given that this was the first implant used in this series, knowledge of inferior baseplate placement likely played a role in the difference in notching rates between the Grammont-style and lateralized humerus designs.

The average position of the inferior glenosphere was 1 mm above the inferior margin of the glenoid in the Grammont group, compared with 5 mm below in the lateralized humeral group. This likely contributed to humeral impingement and secondary notching. However, the notching rate observed in the current study remains within the range reported by previous studies, including those using more modern techniques.7,8

Unlike in the Grammont group, the reported notching rate of the lateralized glenosphere group in the current series was higher than previous reports. In 2008, Cuff et al23 reported on 112 patients treated with a lateralized glenosphere implant at a mean follow-up of 27.5 months, with no patients developing scapular notching. Despite a similar follow-up in the current study, notching with this implant design was higher (57%).

A more recent report on patients younger than 55 years with a mean follow-up of 62 months documented a notching rate of 4.2%.24 It remains unclear why the notching grade in the current study is higher than previous reports. The lateralized glenosphere group in the current study did have the lowest preoperative acromiohumeral interval but had similar postoperative alpha angles as the other groups. The beta angle was significantly greater and the glenosphere overhang was significantly less in the lateralized glenosphere design compared with the lateralized humeral design. Some of this may be related to advancing techniques with lower glenosphere placement and increased inferior tilt. However, with a lateralized glenosphere, the importance of inferior tilt and offset should be lessened due to the glenoid design minimizing inferior humeral impingement.25

Notching of the lateralized humerus design was also higher than previous reports on similar implants. Roche et al22 reported 151 shoulders at a mean follow-up of 28 months treated with the same lateralized humerus design. They reported a scapular notching rate of 13.2%,22 compared with the 22% rate in the current study. The reason for the difference is unclear. It is possible that this may be related to surgeon technique and possibly glenoid version, but this was not evaluated by either study. Inferior overhand was similar in both groups, with Roche et al22 reporting a mean inferior overhand of 4.9 mm compared with 5.7 mm in the current study. Roche et al22 did not assess inferior tilt in relation to the scapular spine, thus the effect of inferior inclination on the rate of notching between groups cannot be assessed.

Although notching rates reported in the current study for all implants are within the described range following RSA, the severity of notching in the Grammont group was significantly greater than in the lateralized humerus group.7–10,21,22,26 Less frequent and severe notching was observed in the lateralized humerus group. As stated previously, the higher rate of notching with the Grammont design is likely partially explained by the learning curve associated with using RSA because these implants were placed higher on the face of the glenoid with less inferior tilt.

Today's developers of the Grammont-style prosthesis have increasingly recognized the importance of lateralization, with some surgeons performing a bio-RSA in an effort to lateralize the CoR and decrease notching.27 Newer reports examining the effect of biologic lateralization with a Grammont-style design have shown lower rates of notching with a bio-RSA configuration (5%) compared with medialized placement of the glenosphere (27.5%).28 Athwal et al6 showed similar improvement with bio-RSA lateralization compared with a medialized baseplate position (40% vs 75%, P=.022). Based on their results, the current authors were unable to evaluate the effect of bio-RSA lateralization with a Grammont prosthesis on notching compared with other implant designs.

Despite the higher rates of notching in the Grammont and lateralized glenosphere groups, patients across all groups demonstrated similar postoperative PROs and range of motion. This is in agreement with the literature, where no single implant design has demonstrated superior results when evaluating similar pathology.4,9,23 The similarities in outcomes despite notching support other small studies, which have not shown scapular notching to affect PROs.6,10,23 However, larger studies with more power have shown poorer outcomes in patients with notching.4,5 Therefore, it is important to consider all modifiable risk factors that may affect notching. Further studies with more surgeons are needed to confirm the effect of implant lateralization design on postoperative notching.

The strength of this study was the direct comparison of 3 implant designs used by a single surgeon, with control for follow-up time. However, several limitations remain beyond the retrospective design. Although the main aim of this study was to assess the role of lateralization on notching, the 3 designs used different humeral neck-shaft angles, which may have affected the rate of notching. Previous studies have demonstrated greater scapular impingement in adduction with higher neck-shaft angles.13

Over time, surgical techniques have changed. The senior surgeon changed the versions of the components between 0° and 30° of humeral retroversion. However, optimal humeral retroversion remains undefined and may vary between patients.29 Surgeons have also learned to place the glenoid component lower, which may have decreased the rate of notching over time. The senior surgeon in this study also began using augmented glenoid baseplates later in the study to increase inferior tilt, thereby increasing the observed inferior tilt seen in the lateralized humerus group.

In addition, there was a comparatively higher number of patients in the lateralized humerus group, which was more commonly implanted later in the study period. This certainly leaves the possibility of beta error, as well as being underpowered to detect some differences, especially between the Grammont and lateralized glenoid groups. Second, follow-up was considered short-term (3 to 5 years), which may underestimate the long-term incidence and grading of scapular notching. However, Simovitch et al5 showed that all shoulders that developed notching did so within 14 months, which is beyond the minimum follow-up for this study. Thus, the incidence of scapular notching remains relevant across designs. In addition, early follow-up may be a possible explanation for the lack of difference seen in PROs.

Patients in the medialized CoR group had a lower body mass index, which has been associated with notching.11 Patients with an elevated body mass index may have soft tissue or body habitus, preventing full adduction of the glenohumeral joint to the position of impingement/notching. The lower body mass index in this group likely represents the more limited indications for RSA earlier in the study period.

Finally, 2-dimensional measures of scapular morphology were used, which are certainly subject to rotational differences across plain radiographs. However, the authors were unable to obtain routine postoperative computed tomography scans due to cost and concern for patient radiation exposure.

Scapular notching remains a concern regarding long-term implant survival and potential impact on patient outcomes. In this single-surgeon series, a lateralized humeral RSA design produced the lowest incidence of scapular notching at early follow-up. Larger multicenter studies evaluating multiple designs are needed to further assess the in vivo performance of RSA design and its effect on long-term notching and PROs.

Conclusion

Lateralized humeral RSA designs showed less frequent and less severe scapular notching compared with Gram-mont and lateralized glenosphere designs in this single-surgeon series. No differences were observed in range of motion, PROs, or revision rates between different implant designs. Caution in interpreting these results should be taken given that implant choice changed during the learning curve of RSA. Further multisurgeon studies are necessary to evaluate the long-term effect of RSA lateralization design on scapular notching.

References

  1. Affonso J, Nicholson GP, Frankle MA, et al. Complications of the reverse prosthesis: prevention and treatment. Instr Course Lect. 2012;61:157–168. PMID:22301230
  2. Ackland DC, Patel M, Knox D. Prosthesis design and placement in reverse total shoulder arthroplasty. J Orthop Surg Res. 2015;10(1):101. doi:10.1186/s13018-015-0244-2 [CrossRef] PMID:26135298
  3. Roche CP, Stroud NJ, Martin BL, et al. The impact of scapular notching on reverse shoulder glenoid fixation. J Shoulder Elbow Surg. 2013;22(7):963–970. doi:10.1016/j.jse.2012.10.035 [CrossRef] PMID:23333170
  4. Mollon B, Mahure SA, Roche CP, Zuckerman JD. Impact of scapular notching on clinical outcomes after reverse total shoulder arthroplasty: an analysis of 476 shoulders. J Shoulder Elbow Surg. 2017;26(7):1253–1261. doi:10.1016/j.jse.2016.11.043 [CrossRef] PMID:28111179
  5. Simovitch RW, Zumstein MA, Lohri E, Helmy N, Gerber C. Predictors of scapular notching in patients managed with the Delta III reverse total shoulder replacement. J Bone Joint Surg Am. 2007;89(3):588–600. doi:10.2106/00004623-200703000-00016 [CrossRef] PMID:17332108
  6. Athwal GS, MacDermid JC, Reddy KM, Marsh JP, Faber KJ, Drosdowech D. Does bony increased-offset reverse shoulder arthroplasty decrease scapular notching?J Shoulder Elbow Surg.2015;24(3):468–473. doi:10.1016/j.jse.2014.08.015 [CrossRef] PMID:25441556
  7. Falaise V, Levigne C, Favard LSOFEC. Scapular notching in reverse shoulder arthroplasties: the influence of glenometaphyseal angle. Orthop Traumatol Surg Res. 2011;97(6) (suppl):S131–S137. doi:10.1016/j.otsr.2011.06.007 [CrossRef] PMID:21820377
  8. Kowalsky MS, Galatz LM, Shia DS, Steger-May K, Keener JD. The relationship between scapular notching and reverse shoulder arthroplasty prosthesis design. J Shoulder Elbow Surg. 2012;21(10):1430–1441. doi:10.1016/j.jse.2011.08.051 [CrossRef] PMID:22079766
  9. Frankle M, Siegal S, Pupello D, Saleem A, Mighell M, Vasey M. The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency: a minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am. 2005;87(8):1697–1705. doi:10.2106/JBJS.D.02813 [CrossRef] PMID:16085607
  10. Katz D, Valenti P, Kany J, Elkholti K, Werthel JD. Does lateralisation of the centre of rotation in reverse shoulder arthroplasty avoid scapular notching? Clinical and radiological review of one hundred and forty cases with forty five months of follow-up. Int Orthop. 2016;40(1):99–108. doi:10.1007/s00264-015-2976-3 [CrossRef] PMID:26338343
  11. Langohr GDG, Willing R, Medley JB, Athwal GS, Johnson JA. Contact mechanics of reverse total shoulder arthroplasty during abduction: the effect of neck-shaft angle, humeral cup depth, and glenosphere diameter. J Shoulder Elbow Surg. 2016;25(4):589–597. doi:10.1016/j.jse.2015.09.024 [CrossRef] PMID:26704359
  12. Hettrich CM, Permeswaran VN, Goetz JE, Anderson DD. Mechanical tradeoffs associated with glenosphere lateralization in reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2015;24(11):1774–1781. doi:10.1016/j.jse.2015.06.011 [CrossRef] PMID:26238003
  13. Oh JH, Shin S-J, McGarry MH, Scott JH, Heckmann N, Lee TQ. Biomechanical effects of humeral neck-shaft angle and subscapularis integrity in reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2014;23(8):1091–1098. doi:10.1016/j.jse.2013.11.003 [CrossRef] PMID:24480326
  14. Giles JW, Langohr GDG, Johnson JA, Athwal GS. Implant design variations in reverse total shoulder arthroplasty influence the required deltoid force and resultant joint load. Clin Orthop Relat Res. 2015;473(11):3615–3626. doi:10.1007/s11999-015-4526-0 [CrossRef] PMID:26310680
  15. Flatow EL, Harrison AK. A history of reverse total shoulder arthroplasty. Clin Orthop Relat Res. 2011;469(9):2432–2439. doi:10.1007/s11999-010-1733-6 [CrossRef] PMID:21213090
  16. Bufquin T, Hersan A, Hubert L, Massin P. Reverse shoulder arthroplasty for the treatment of three- and four-part fractures of the proximal humerus in the elderly: a prospective review of 43 cases with a short-term follow-up. J Bone Joint Surg Br. 2007;89(4):516–520. doi:10.1302/0301-620X.89B4.18435 [CrossRef] PMID:17463122
  17. Maurer A, Fucentese SF, Pfirrmann CWA, et al. Assessment of glenoid inclination on routine clinical radiographs and computed tomography examinations of the shoulder. J Shoulder Elbow Surg. 2012;21(8):1096–1103. doi:10.1016/j.jse.2011.07.010 [CrossRef] PMID:22036540
  18. Sirveaux F, Favard L, Oudet D, Huquet D, Walch G, Molé D. Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff: results of a multicentre study of 80 shoulders. J Bone Joint Surg Br. 2004;86(3):388–395. doi:10.1302/0301-620X.86B3.14024 [CrossRef] PMID:15125127
  19. Aibinder WR, Clark NJ, Schoch BS, Steinmann SP. Assessing glenosphere position: superior approach versus deltopectoral for reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2018;27(3):455–462. doi:10.1016/j.jse.2017.10.013 [CrossRef] PMID:29273388
  20. Sperling JW, Cofield RH, O'Driscoll SW, Torchia ME, Rowland CM. Radiographic assessment of ingrowth total shoulder arthroplasty. J Shoulder Elbow Surg. 2000;9(6):507–513. doi:10.1067/mse.2000.109384 [CrossRef] PMID:11155304
  21. Lévigne C, Garret J, Boileau P, Alami G, Favard L, Walch G. Scapular notching in reverse shoulder arthroplasty: is it important to avoid it and how?Clin Orthop Relat Res.2011;469 (9):2512–2520. doi:10.1007/s11999-010-1695-8 [CrossRef] PMID:21116754
  22. Roche CP, Marczuk Y, Wright TW, et al. Scapular notching and osteophyte formation after reverse shoulder replacement: radiological analysis of implant position in male and female patients. Bone Joint J. 2013; 95-B(4):530–535. doi:10.1302/0301-620X.95B4.30442 [CrossRef] PMID:23539706
  23. Cuff D, Pupello D, Virani N, Levy J, Frankle M. Reverse shoulder arthroplasty for the treatment of rotator cuff deficiency. J Bone Joint Surg Am. 2008;90(6):1244–1251. doi:10.2106/JBJS.G.00775 [CrossRef] PMID:18519317
  24. Otto RJ, Clark RE, Frankle MA. Reverse shoulder arthroplasty in patients younger than 55 years: 2- to 12-year follow-up. J Shoulder Elbow Surg. 2017;26(5):P792–797. doi doi:10.1016/j.jse.2016.09.051 [CrossRef]
  25. Li X, Knutson Z, Choi D, et al. Effects of glenosphere positioning on impingement-free internal and external rotation after reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2013;22(6):807–813. doi:10.1016/j.jse.2012.07.013 [CrossRef] PMID:22999850
  26. Feeley BT, Zhang AL, Barry JJ, et al. Decreased scapular notching with lateralization and inferior baseplate placement in reverse shoulder arthroplasty with high humeral inclination. Int J Shoulder Surg. 2014;8(3):65–71. doi:10.4103/0973-6042.140112 [CrossRef] PMID:25258496
  27. Boileau P, Morin-Salvo N, Gauci M-O, et al. Angled BIO-RSA (bony-increased offset-reverse shoulder arthroplasty): a solution for the management of glenoid bone loss and erosion. J Shoulder Elbow Surg. 2017;26(12):2133–2142. doi:10.1016/j.jse.2017.05.024 [CrossRef] PMID:28735842
  28. Collin P, Liu X, Denard PJ, Gain S, Nowak A, Lädermann A. Standard versus bony increased-offset reverse shoulder arthroplasty: a retrospective comparative cohort study. J Shoulder Elbow Surg. 2018;27(1):59–64. doi:10.1016/j.jse.2017.07.020 [CrossRef] PMID:28969891
  29. Kontaxis A, Chen X, Berhouet J, et al. Humeral version in reverse shoulder arthroplasty affects impingement in activities of daily living. J Shoulder Elbow Surg. 2017;26(6):1073–1082. doi:10.1016/j.jse.2016.11.052 [CrossRef] PMID:28162877

Demographic Data for All Reverse Shoulder Arthroplasties by Implant Design

CharacteristicGrammontLateralized GlenosphereLateralized HumerusPP for Post hoc Test

Lateralized Glenosphere vs GrammontLateralized Glenosphere vs Lateralized HumerusGrammont vs Lateralized Humerus
Age, mean (SD), y70.5 (6.4)73.7 (5.7)72 (8.0).4
Female64.70%64.30%56.80%.7
Follow-up, mean (SD), mo48.1 (11.7)51.3 (11.9)49.1 (10.5).7
Body mass index, mean (SD), kg/m220.3 (20.3)30.4 (7.1)29.3 (5.4).009.0411.009

Preoperative Radiographic Measures by Implant Design

MeasureGrammontLateralized GlenosphereLateralized HumerusPP for Post hoc Test

Lateralized Glenosphere vs GrammontLateralized Glenosphere vs Lateralized HumerusGrammont vs Lateralized Humerus
Acromiohumeral interval, mean (SD), mm2.5 (3.4)1.4 (2.2)4.1 (3.5).005.3.005.07
Alpha angle, mean (SD)132.3° (6.7°)133. 0° (5.0°)136.4° (7.4°).06
Beta angle, mean (SD)77.1° (6.4°)81.7° (6.9°)80.0° (12.7°).3

Postoperative Radiographic Measures by Implant Design

MeasureGrammontLateralized GlenosphereLateralized HumerusPP for Post hoc Test

Lateralized Glenosphere vs GrammontLateralized Glenosphere vs Lateralized HumerusGrammont vs Lateralized Humerus
Alpha angle, mean (SD)141.6° (8.9°)142.8° (8.4°)137.7° (10.3°).1
Beta angle, mean (SD)84.4° (10.1°)88.2° (6.9°)82.3° (7.5°).032.3.0281
Glenosphere overhang, mean (SD), mm−1.35 (4.4)0.66 (1.1)5.68 (2.8)<.0011<.001<.001
Scapular neck length, mean (SD), mm8.5 (3.5)8.7 (3.5)9.9 (4.0).2
Notch (no./total no.)82% (14/17)57% (8/14)22% (28/125)<.001
Notching grade, mean (SD)2.06 (1.4)1.07 (1.3)0.24 (0.5)<.001.2.009<.001

Postoperative Patient-Reported Outcomes by Implant Design

OutcomeMean (SD)P

GrammontLateralized GlenosphereLateralized Humerus
Preoperative pain score7.5 (3.5)7.1 (1.8)6 (2.4).4
Postoperative pain score2.1 (2.7)2.4 (2.8)1.6 (2.2).3
SPADI25.2 (17.8)35.5 (22.8)26.4 (22.5).3
SPADI 13034.3 (23.2)47.9 (29.5)35.6 (29.3).2
SST score9 (2.6)8.4 (3.1)8.8 (3.2).8
ASES score76.4 (16.5)68 (22.4)75.5 (19.8).4
UCLA shoulder score27.3 (4.5)24.8 (7.8)27.9 (6.0).2
Constant score69.9 (15.0)66 (17.9)71.7 (16.9).5
SF-12 score35.4 (7.1)33.5 (8.6)34 (7.7).8
External rotation24° (26.9°)33° (21.7°)26° (19.1°).6
Elevation118° (31.8°)103° (36.7°)121° (24.3°).2
Abduction111° (29.9°)100° (29.6°)113° (25.7°).4
Authors

The authors are from the Department of Orthopedics (BSS), Mayo Clinic, Jacksonville, and the Department of Orthopaedic Surgery and Rehabilitation (HT, JJK, TWW), University of Florida, Gainesville, Florida; and the Department of Orthopaedic Surgery and Rehabilitation Medicine (WA), SUNY Downstate Health Sciences University, Brooklyn, New York.

Drs Taba, Aibinder, and King have no relevant financial relationships to disclose. Dr Schoch is a paid consultant for Exactech. Dr Wright is a paid consultant for and receives royalties from Exactech.

The authors thank Aimee Struk for her assistance with data collection.

Correspondence should be addressed to: Bradley S. Schoch, MD, Department of Orthopedics, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224 ( schoch.bradley@mayo.edu).

Received: May 13, 2019
Accepted: September 05, 2019
Posted Online: August 20, 2020

10.3928/01477447-20200812-10

Sign up to receive

Journal E-contents