Glenohumeral osteoarthritis is a common and debilitating condition that significantly impairs shoulder mobility, function, and quality of life [1]. It represents one of the leading indications for shoulder arthroplasty in adults over 55 years, with prevalence increasing markedly with age and showing a slight female predominance [2]. Degenerative changes of the glenohumeral joint are strongly associated with age-related cartilage wear, altered joint biomechanics, rotator cuff integrity, glenoid morphology, and prior trauma or instability [3,4]. Before surgical intervention is considered, patients typically undergo conservative management, including activity modification, physiotherapy, nonsteroidal anti-inflammatory drugs, intra-articular corticosteroid or hyaluronic acid injections, and analgesic regimens [5]. These measures aim to reduce pain and preserve function but often provide diminishing benefit as structural degeneration progresses [6]. For patients with advanced disease that is refractory to nonoperative treatment, anatomic total shoulder arthroplasty (TSA) remains the gold-standard surgical option [7].

Glenoid component fixation represents a critical determinant of implant longevity and clinical success in TSA [8]. Keeled and pegged glenoid components are the two most widely used designs. Both aim to restore joint congruency, alleviate pain, and improve function, yet they differ fundamentally in fixation geometry, bone preparation requirements, cement distribution, and theoretical load transfer to the glenoid bone [9,10]. These design differences have prompted ongoing debate over their relative performance, particularly with respect to radiographic loosening, implant survivorship, and the risk of revision [11].

Despite extensive primary comparative studies, the remaining clinical uncertainty is not whether patients improve after anatomic TSA, as short to mid-term patient-reported outcomes with keeled and pegged components are similar in most studies, but whether one design confers a clinically relevant survivorship advantage when contemporary data are pooled [12]. Prior evidence syntheses have been constrained by heterogeneous implant eras and methods. Critically, many of the comparative cohorts used for pooled estimates of revision outcomes have limited long-term follow-up, which reduces power to resolve small but consequential differences in durability [13]. Since those earlier syntheses, large contemporary observational datasets and newer long-term comparative cohorts have added revision-specific information capable of shifting pooled survivorship estimates and improving precision [14]. Accordingly, an updated meta-analysis is needed to focus specifically on primary osteoarthritis and anatomic TSA. Emphasizing revision-related endpoints in addition to patient-reported outcome measures (PROMs) and range of motion (ROM) would better inform implant selection when the clinical trade-off is “equivalent function” but potentially different long-term durability.

Keeled glenoid components use a single central keel to achieve fixation within the glenoid vault and have a long history of clinical use. They are often considered technically straightforward and provide robust initial fixation, particularly in patients with adequate bone stock [15,16]. Pegged glenoid components, in contrast, rely on multiple smaller pegs, typically cemented, to enhance fixation and potentially reduce stress shielding and micromotion at the bone–implant interface [17]. The theoretical advantages in bone preservation and load distribution of pegged designs have increased their use, although concerns about cement mantle integrity, radiolucent line formation, and long-term durability persist [18]. Differences in glenoid morphology, bone quality, and patient age further complicate implant selection and may influence outcomes [19].

These contrasting design philosophies translate into distinct risk profiles and postoperative considerations. While both keeled and pegged glenoid components generally provide reliable pain relief and functional improvement, glenoid loosening remains the most common cause of failure following anatomic TSA. Advances in implant design, cementing techniques, and surgical instrumentation have improved outcomes for both designs, yet conflicting evidence persists regarding radiographic performance, revision rates, and long-term survivorship. However, the most clinically relevant unresolved question is whether any survivorship differences become detectable once newer long-term cohorts and large contemporary datasets are incorporated, particularly for revision outcomes that individual studies are often underpowered to detect. Therefore, this review updates prior syntheses by extending the search through December 2025 and pooling contemporary comparative evidence, including large registry-based revision risk analyses and newer long-term matched cohorts, while maintaining a focused indication (primary osteoarthritis) and procedure type (anatomic TSA). In addition to PROMs and ROM, we prioritize implant survivorship endpoints (revision and failure) to translate the keeled-versus-pegged debate into decision-relevant risk estimates for surgeons counseling patients about durability.

This study did not require institutional review board approval because it is a meta-analysis of previously published studies.

The principal finding of this meta-analysis is that pegged and keeled glenoid components in anatomic TSA provide comparable patient-reported outcomes and overall shoulder motion, and pegged designs are associated with a significantly lower risk of revision surgery. Across pooled analyses, no meaningful differences were observed in validated functional scores or pain measures, and ROM outcomes were largely equivalent, except for a modest advantage in internal rotation favoring pegged components. Collectively, these findings suggest that while both glenoid designs reliably achieve pain relief and functional restoration, the primary goals of TSA, implant survivorship may differ in clinically relevant ways.

This meta-analysis demonstrated no significant differences between pegged and keeled glenoid components across PROMs, which included ASES, Constant-Murley, SST, and VAS pain scores. These findings indicate that both designs are equally effective in improving pain, daily function, and overall patient satisfaction following anatomic TSA [34]. The absence of PROM differences may reflect the multifactorial nature of patient-perceived outcomes, which are strongly influenced by rotator cuff integrity, humeral component positioning, soft-tissue balancing, and postoperative rehabilitation rather than glenoid fixation geometry alone [35]. Prior comparative studies and registry analyses have also reported equivalent PROMs between glenoid designs, reinforcing the view that modern cemented keeled and pegged components both achieve reliable clinical improvement [36,37].

However, preoperative baseline functional scores and radiographic disease severity were not consistently reported across the included comparative studies. Several of the included studies did report baseline PROMs [22,25,28-31,33], whereas the remaining studies were primarily survivorship or radiographic-focused and did not provide baseline PROM reporting. Moreover, even among studies that reported baseline PROMs, preoperative equivalence was not always demonstrated. For instance, baseline ASES and WOOS differed significantly between groups in Gascoyne et al. [25], and baseline pain scores differed in Moulton et al. [29]. Given that baseline function and radiographic glenoid severity (e.g., Walch classification, erosion, subluxation) influence postoperative recovery potential, this heterogeneous reporting limits the extent to which pooled PROMs can isolate the full effect of glenoid fixation design. Furthermore, statistical heterogeneity varied across PROMs (e.g., Constant-Murley I²=0% vs. ASES/SST/VAS showing moderate I²). Even when I² is low, it should not be interpreted as the absence of clinical heterogeneity, as the included cohorts differed in baseline patient characteristics and follow-up duration. From a surgical perspective, these findings suggest that glenoid design selection alone should not be expected to drive differences in short to mid-term patient-reported outcomes, and that meticulous surgical technique and appropriate patient selection remain the dominant determinants of perceived success [38].

Regarding shoulder ROM, pooled analyses revealed no significant differences in postoperative flexion or external rotation between groups [39]. Although statistical heterogeneity was low to moderate for these ROM outcomes, relevant clinical variability may persist across studies due to differences in rehabilitation protocols, surgical technique, and baseline stiffness. Additionally, baseline ROM was not uniformly reported across all comparative cohorts. Internal rotation demonstrated a statistically significant advantage favoring pegged glenoid components; however, this finding must be interpreted cautiously [40]. The number of contributing studies was limited, and the observed MD was small and probably below established minimal clinically important difference thresholds for shoulder motion, suggesting minimal functional relevance [41]. In addition, the low I² estimate for internal rotation should be interpreted cautiously, given the small number of studies, which limits the ability of heterogeneity statistics to detect between-study variability. Biomechanically, improved internal rotation with pegged designs may relate to more uniform cement distribution, reduced stress concentration, or improved humeral head centering, but these effects appear modest in clinical practice [42]. Existing literature generally reports comparable postoperative ROM between glenoid designs, with variations more strongly influenced by preoperative stiffness, capsular management, subscapularis handling, and rehabilitation protocols [43,44]. Consequently, although the observed difference in internal rotation is statistically detectable, it does not support a meaningful overall ROM advantage for either glenoid design.

In contrast, implant-related outcomes revealed a clinically important difference in revision risk, with pegged glenoid components being associated with a significantly lower likelihood of revision surgery compared with keeled components. Although statistical heterogeneity was low (I²=0%), this should not be interpreted as true homogeneity, as revision outcomes remain highly dependent on clinical differences across cohorts (implant generation, cementing technique, and follow-up duration) and are disproportionately weighted by large registry-based datasets. Furthermore, stratified analysis by study design suggested that the observed revision advantage was primarily driven by observational evidence. Additionally, revision is a time-dependent endpoint, and heterogeneity in follow-up duration across studies limits the interpretation of pooled revision risk as a uniform long-term survivorship comparison. Residual confounding may also reflect implant generation and surgical era differences across cohorts, which could influence revision risk independent of keel versus peg geometry. Revision thresholds and indications differed across studies and follow-up strategies. Accordingly, pooled revision estimates reflect a range of clinically treated reinterventions. Furthermore, sensitivity analysis excluding the large registry-based cohorts demonstrated a consistent direction of effect, although with reduced precision. This supports robustness of direction, but does not eliminate residual confounding related to indication, implant era, or follow-up duration. Notably, this difference was not mirrored by a significant difference in reported failure rates, suggesting that revisions may occur due to progressive loosening, pain, or surgeon-driven decision-making rather than overt implant failure alone [45]. Interpretation of pooled failure outcomes should also account for variability in failure definitions across studies, which may not be captured by low statistical heterogeneity metrics. Pegged glenoid components may confer improved long-term fixation through more favorable load distribution, reduced micromotion, and diminished stress concentration within the glenoid vault [46]. Prior biomechanical, radiographic, and registry-based studies have similarly identified lower loosening and revision rates with pegged designs, particularly at mid to long-term follow-up [27,47]. Clinically, reduced revision risk is a highly relevant endpoint, as revision TSA carries increased morbidity, technical complexity, and inferior outcomes compared with primary procedures [48]. Therefore, although our findings suggest an association between pegged glenoid design and reduced revision risk, this advantage should be interpreted as associative rather than definitively causal, and should be integrated with patient-specific anatomy and surgeon technique when selecting implants.

Beyond glenoid design alone, multiple additional factors critically influence outcomes following anatomic TSA and warrant consideration in clinical decision-making [49]. Glenoid morphology, bone stock quality, version abnormalities, and Walch classification strongly affect fixation success and long-term stability, often outweighing design-related differences [50,51]. Surgeon experience, cementing technique, component positioning, and soft-tissue balancing play decisive roles in preventing loosening and optimizing function [52,53]. Furthermore, outcomes not specifically analyzed in this meta-analysis, including radiolucent line progression, scapular notching, polyethylene wear, patient satisfaction, cost-effectiveness, and ease of revision, have been inconsistently reported in the literature, with mixed findings between keeled and pegged designs [54,55]. Some studies suggest increased radiographic lucency with keeled components, while others report equivalent radiographic performance when modern cementing techniques are used [56,57]. These data reinforce the conclusion that glenoid design functions within a broader biomechanical and surgical ecosystem rather than acting as an isolated determinant of success.

In summary, the available evidence supports a measured, patient-centered approach to glenoid selection in anatomic TSA. Both pegged and keeled glenoid components provide comparable pain relief, functional improvement, and overall shoulder motion. Pegged designs may offer an advantage in long-term implant survivorship through reduced revision risk. However, given the equivalence of most clinical outcomes, glenoid selection should be individualized based on glenoid anatomy, bone quality, patient age and activity level, and surgeon expertise rather than an expectation of superior global function. Optimizing outcomes in anatomic TSA ultimately depends on comprehensive preoperative planning, precise surgical execution, and alignment of implant choice with patient-specific anatomical and functional goals.

This meta-analysis has several limitations that warrant consideration. First, many of the included studies were retrospective, with various follow-up durations, increasing susceptibility to selection bias and residual confounding, including confounding by indication, despite matching or statistical adjustment. Thus, pooled estimates may reflect mixed short, mid, and long-term follow-up rather than a uniform survivorship interval. In fact, the pooled survivorship outcomes were heavily influenced by non-randomized observational and registry-based studies. Second, baseline preoperative functional status and radiographic disease severity were not consistently reported across the included studies, and some studies that reported PROMs demonstrated missing baseline values or baseline group differences, limiting assessment of baseline comparability between keeled and pegged cohorts. This was particularly notable in registry/survivorship and radiographic-focused studies. Third, variation in implant design generation, cementing techniques, surgical approaches, and rehabilitation protocols may independently affect outcomes and limit direct comparability, even when statistical heterogeneity estimates are low. Implant generation and surgical era were not consistently reported, and improvements in polyethylene quality, cementing technique, and instrumentation over time may have contributed to survivorship differences independent of keel or peg geometry. Fourth, not all studies reported complete quantitative data for all outcomes, restricting pooling for certain measures and necessitating narrative synthesis in some domains. Fifth, radiographic assessment methods and definitions of loosening varied across studies, potentially contributing to measurement inconsistency. Relatedly, definitions of implant failure and revision varied across studies, which may affect the comparability of pooled survivorship endpoints, particularly revision, because pooled estimates may combine operative events arising from different indications and reintervention thresholds across cohorts. Finally, long-term outcomes remain underrepresented in high-quality randomized trials, underscoring the need for further prospective studies with standardized reporting to refine evidence on glenoid component performance.

In summary, this meta-analysis demonstrates that both pegged and keeled glenoid components in anatomic TSA provide effective pain relief and meaningful functional improvement for patients with degenerative glenohumeral disease. Most functional and PROMs were comparable between designs. Although a small statistical difference in internal rotation favored pegged components, its clinical relevance appears limited. In contrast, pegged glenoid components were associated with a significantly lower risk of revision, particularly in observational evidence, which may indicate a potential advantage in implant durability and long-term survivorship. However, keeled glenoid components achieved similar clinical outcomes and remain a dependable option when appropriately selected.

These findings suggest that pegged glenoid components may be preferential for patients prioritizing long-term implant durability and revision avoidance, whereas keeled glenoid components remain suitable in selected anatomical scenarios and surgical settings. Ultimately, optimal outcomes in anatomic TSA are driven less by a universal implant preference and more by individualized surgical planning, meticulous technique, and the careful alignment of implant choice with patient-specific anatomy, biomechanics, and functional expectations.