Restricted accessResearch articleFirst published online 2025
Glenoid lateralization angle influences the rate of scapular notching after reverse shoulder arthroplasty: A retrospective cohort study on 139 patients with minimum 2 years follow up from the FP-UCBM Shoulder Study Group
The glenoid lateralization angle (GLA), humeral lateralization angle (HLA), glenoid distalization angle (GDA), and humeral distalization angle (HDA) are new coronal parameters used to assess glenoid and humeral positioning in reverse shoulder arthroplasty (RSA). This study aimed to correlate these angles with scapular notching (SN) and clinical outcomes to guide component placement.
Methods
A retrospective analysis of 139 patients undergoing primary RSA was performed. Clinical outcomes, including Constant-Murley score, simple shoulder test, visual analog scale, and range of motion, were collected preoperatively and at 24 months postoperatively. Radiographic evaluation included the measurement of GLA, HLA, GDA, and HDA on Grashey projection X-rays, alongside the incidence and grade of SN.
Results
GLA was significantly associated with a reduced probability of SN (p = .002), with a threshold of 51.5° identified as critical for increased notching risk. No correlation was found between clinical outcomes or ROM and any of the measured angles (p > .05). Radiographic reliability was high (κ = 0.89).
Conclusions
GLA, HLA, GDA, and HDA are reproducible measures. Only reduced glenoid lateralization (GLA < 51.5°) was linked to increased scapular notching, underscoring its importance in preoperative planning, while distalization and humeral angles showed minimal clinical influence.
SamitierGAlentorn-GeliETorrensC, et al.Reverse shoulder arthroplasty. Part 1: systematic review of clinical and functional outcomes. Int J Shoulder Surg2015; 9: 24–31.
2.
FranceschettiEGregoriPDe GiorgiS, et al.Machine learning can predict anterior elevation after reverse total shoulder arthroplasty: a new tool for daily outpatient clinic?Musculoskelet Surg2024; 108: 163–171.
BoileauPWatkinsonDJHatzidakisAM, et al.Grammont reverse prosthesis: design, rationale, and biomechanics. J Shoulder Elbow Surg2005; 14: S147–S161.
5.
BacleGNové-JosserandLGaraudP, et al.Long-term outcomes of reverse total shoulder arthroplasty: a follow-up of a previous study. J Bone Joint Surg Am2017; 99: 454–461.
6.
ShethMMHeldtBLSpellJH, et al.Patient satisfaction and clinical outcomes of reverse shoulder arthroplasty: a minimum of 10 years’ follow-up. J Shoulder Elbow Surg2022; 31: 875–883.
7.
BerhouetJGaraudPFavardL. Evaluation of the role of glenosphere design and humeral component retroversion in avoiding scapular notching during reverse shoulder arthroplasty. J Shoulder Elbow Surg2014; 23: 151–158.
8.
FranceschettiEPerriconeGDe RosaA, et al.Eccentricity and greater size of the glenosphere increase impingement-free range of motion in glenoid lateralized reverse shoulder arthroplasty: a computational study. J Clin Orthop Trauma2024; 56: 102527.
9.
RoutmanHDFlurinP-HWrightTW, et al.Reverse shoulder arthroplasty prosthesis design classification system. Bull Hosp Jt Dis2015; 73: S5–S14.
10.
BoutsiadisALenoirHDenardPJ, et al.The lateralization and distalization shoulder angles are important determinants of clinical outcomes in reverse shoulder arthroplasty. J Shoulder Elbow Surg2018; 27: 1226–1234.
11.
SchippersPLacoutureJ-DJunkerM, et al.Can we separately measure glenoid vs. humeral lateralization and distalization in reverse shoulder arthroplasty?J Shoulder Elbow Surg2024; 33: 1169–1176.
12.
FranceschettiEGiovannetti de SanctisEGregoriP, et al.Angled BIO-RSA leads to better inclination and clinical outcomes compared to standard BIO-RSA and eccentric reaming: a comparative study. Shoulder Elbow2023; 15: 35–42.
13.
SirveauxFFavardLOudetD, et al.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 Br2004; 86-B: 388–395.
14.
VrotsouKÁvilaMMachónM, et al.Constant–Murley score: systematic review and standardized evaluation in different shoulder pathologies. Qual Life Res2018; 27: 2217–2226.
15.
TashjianRZHungMKeenerJD, et al.Determining the minimal clinically important difference for the American shoulder and elbow surgeons score, simple shoulder test, and visual analog scale (VAS) measuring pain after shoulder arthroplasty. J Shoulder Elbow Surg2017; 26: 144–148.
16.
RoyJSMacdermidJCFaberKJ, et al.The simple shoulder test is responsive in assessing change following shoulder arthroplasty. J Orthop Sports Phys Ther2010; 40: 413–421.
17.
GerberCPenningtonSDNyffelerRW. Reverse total shoulder arthroplasty. J Am Acad Orthop Surg2009; 17: 284–295.
18.
LévigneCGarretJBoileauP, et al.Scapular notching in reverse shoulder arthroplasty: is it important to avoid it and how?Clin Orthop Relat Res2011; 469: 2512–2520.
19.
FranceschettiEGregoriPGiovannetti de SanctisE, et al.Return to sport after total shoulder arthroplasty and hemiarthroplasty: a systematic review. Sports Med Arthrosc Rev2023; 31: 27–32.
20.
MollonBMahureSARocheCP, et al.Impact of scapular notching on clinical outcomes after reverse total shoulder arthroplasty: an analysis of 476 shoulders. J Shoulder Elbow Surg2017; 26: 1253–1261.
21.
CheungEWillisMWalkerM, et al.Complications in reverse total shoulder arthroplasty. J Am Acad Orthop Surg2011; 19: 439–449.
22.
BigorreNLanciguRBizotP, et al.Predictive factors of scapular notching in patients with reverse shoulder arthroplasty. Orthop Traumatol Surg Res2014; 100: 711–714.
23.
FriedmanRJBarcelDAEichingerJK. Scapular notching in reverse total shoulder arthroplasty. J Am Acad Orthop Surg2019; 27: 200–209.
24.
SimovitchRFlurinP-HWrightTW, et al.Impact of scapular notching on reverse total shoulder arthroplasty midterm outcomes: 5-year minimum follow-up. J Shoulder Elbow Surg2019; 28: 2301–2307.
25.
NicholsonGPStraussEJShermanSL. Scapular notching: recognition and strategies to minimize clinical impact. Clin Orthop Relat Res2011; 469: 2521–2530.
26.
LawrenceCWilliamsGRNamdariS. Influence of glenosphere design on outcomes and complications of reverse arthroplasty: a systematic review. Clin Orthop Surg2016; 8: 288–297.
BoileauPMoineauGRoussanneY, et al.Bony increased-offset reversed shoulder arthroplasty: minimizing scapular impingement while maximizing glenoid fixation. Clin Orthop Relat Res2011; 469: 2558–2567.
29.
FreisledererFToftFAudigéL, et al.Lateralized vs. classic Grammont-style reverse shoulder arthroplasty for cuff deficiency Hamada stage 1-3: does the design make a difference?J Shoulder Elbow Surg2022; 31: 341–351.
30.
SacconeLde SanctisEGCaldariaA, et al.Modified distalization shoulder angle and lateralization shoulder angle show weakly correlation with clinical outcomes following reverse shoulder arthroplasty. J Shoulder Elbow Surg2025; 34: 1650–1657.
