Comparison of Lateralized Versus Medialized Reverse Total Shoulder Arthroplasty: A Systematic Review and Meta-analysis

Abstract

Background: Reverse total shoulder arthroplasty (rTSA) is an established procedure for cuff tear arthropathy. More lateralized prostheses have been designed to overcome the reported adverse outcomes of Grammont-style rTSA. Purpose: To compare the clinical and radiological outcomes of medialized and lateralized center of rotation (COR) in rTSA. Study Design: Systematic review; Level of evidence, 3. Methods: This review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were studies with a level of evidence ≥3 that compared medialized and lateralized rTSA with a minimum follow-up of 12 months. Functional scores including the American Shoulder and Elbow Surgeons (ASES) score and Constant score (CSS), range of motion at final follow-up, gain of external rotation (ER), visual analog scale (VAS) pain score, scapular notching, and heterotopic ossification (HO) were compared. Data were analyzed using random-effects or fixed-effects models in accordance with heterogeneity. Results: Five retrospective cohort studies and 1 randomized controlled study (n = 594 patients) were included. Lateralized rTSA resulted in greater improvement in ER degree ( P < .001), a lower VAS pain score (standardized mean difference [SMD], –0.39; P = .002), and a lower rate of scapular notching (risk ratio [RR], 0.40; P < .001) and HO (RR, 0.52; P < .001). Final forward flexion (SMD, –0.14; P = .629) and ER (SMD, 0.21; P = .238) did not differ significantly between the 2 groups. Overall functional scores, including ASES score (SMD, 0.22; P = .310) and CSS (SMD, 0.37; P = .077), also did not differ significantly (SMD, 0.28; P = .062). The overall complication rate did not differ significantly between the 2 groups (RR, 0.71; P = .339). Conclusion: Compared with medialized rTSA, lateralized COR rTSA results in greater improvement in ER and the VAS pain score, decreased rates of scapular notching and HO, and no significant changes in functional outcome scores or the complication rate.

Influence of lateralized versus medialized reverse shoulder arthroplasty design on external and internal rotation: a systematic review and meta-analysis

“…They also found that lateralized versus medialized RSA had lower rates of scapular notching (6.6% vs. 47.7%, P<0.01) and postoperative infection (1% vs. 7.7%, P=0.01). Berton et al [ 3 ] used stricter inclusion and exclusion criteria in their study compared to Cho et al, [ 5 ] and their work was more similar to the present study, as they included studies reporting on patients with indications limited to cuff tear arthropathy, irreparable cuff tear, or cuff tear associated with osteoarthritis. Although Berton et al [ 3 ] also excluded studies including patients undergoing revision RSA or an indication of rheumatoid arthritis, acute fracture, post-traumatic fracture sequelae, tumor, or active infection, the authors only required 1 year of follow-up.…”

“…Prior meta-analyses have been conducted to compare axial ROM after lateralized versus medialized RSA [ 3 , 5 , 51 ]; however, their inclusion and exclusion criteria vary. Cho et al [ 5 ] included five studies that compared lateralized (n=346) versus medialized (n=217) RSA and found no difference in postoperative ER (standardized mean difference, 0.21 [−0.14 to 0.56]; P=0.238); however, pre- to postoperative improvement in ER favored lateralized RSA in their analysis of two studies (standardized mean difference, 0.71 [0.36–1.07]; P<0.001). Although Cho et al [ 5 ] similarly classified implant lateralization using the classification proposed by Werthel et al, [ 45 ], the authors only included comparative studies, limiting study inclusion.…”

“…Cho et al [ 5 ] included five studies that compared lateralized (n=346) versus medialized (n=217) RSA and found no difference in postoperative ER (standardized mean difference, 0.21 [−0.14 to 0.56]; P=0.238); however, pre- to postoperative improvement in ER favored lateralized RSA in their analysis of two studies (standardized mean difference, 0.71 [0.36–1.07]; P<0.001). Although Cho et al [ 5 ] similarly classified implant lateralization using the classification proposed by Werthel et al, [ 45 ], the authors only included comparative studies, limiting study inclusion. Furthermore, the authors did not specifically exclude studies with patients with preoperative diagnoses associated with poorer prognoses (i.e., post-traumatic, post-infectious, inflammatory arthritis, revision arthroplasty), severe bone loss, concomitant tendon transfer, or less than 2 years of follow-up.…”

“…Consequently, these reports led many to believe that RSA leads to poor active ER and poor active and passive IR. Nevertheless, it appears that, despite these reported limitations in measured axial ROM, patients can manage toileting (which requires active IR) after unilateral and even after bilateral RSA [ 5 - 7 ].…”

Implant selection for successful reverse total shoulder arthroplasty

“…For greater bone preservation, a shorter stem length and a stemless design of the humeral component emerged. Furthermore, the concept of lateralization was presented to overcome problems from medialization of the COR such as loss of shoulder contour, reduced stability of the artificial joint, weaker external and internal rotation power, and scapular notching [9][10][11][12]. However, the lateralized implant could decompensate the advantages of medialization of the COR.…”