Summary AETOS Shoulder System is a metaphyseal, in-lay humeral platform that recenters on the anatomic neck cut, uses concentric humeral heads, and is delivered with a streamlined tray workflow for efficient anatomic and reverse shoulder arthroplasty. recenters on the anatomic neck cut uses concentric humeral heads and is delivered with a streamlined tray workflow for efficient anatomic and reverse shoulder arthroplasty. It is used for anatomic TSA with an anatomic 4-peg glenoid and for reverse RSA via the Meta Stem. The stemless humeral option is indicated for anatomic TSA only and availability varies by market. Unique value in daily practice: the Angulator for version-correcting glenoid/baseplate reaming intra-operative TSA→RSA convertibility on the same humeral platform and cruciate fins that aid humeral centering and metaphyseal stability. Related Implants Humeral Meta Stem (sizes 1–4) In-lay collar sits flush with the resection to preserve joint line Cruciate fins: A/P fins resist varus–valgus; M/L fins add rotational stability A/P fins resist varus–valgus M/L fins add rotational stability Tapered distal segment to minimize diaphyseal engagement Lateral curve to respect greater tuberosity contour Porous titanium plasma-spray coating for metaphyseal ongrowth Humeral heads (anatomic, concentric) Ten sizes defined by width × height For each base width, the head height varies to tune articular mismatch and soft-tissue tension Representative examples: 47-16, 47-18, 50-21, 53-22 Anatomic glenoids Sizes XS–L, cemented 4-peg oval backside with longitudinal flutes Standard and full-wedge posterior augments at 5° and 10° Posterior augment thickness rises with size (e.g., XS through L from low- to mid-single-digit millimeters) Reverse components Baseplates: centered, eccentric, and full-wedge 10°/15° options centered, eccentric, and full-wedge 10°/15° options Central post accepts optional 10- or 15-mm post extensions Central screw available for centered baseplate only Glenospheres: 34/38/42 mm in concentric or eccentric variants; lateralization options include +0/+3 mm (34 mm has a +1 mm lateralization variant) 34/38/42 mm in concentric or eccentric variants lateralization options include +0/+3 mm (34 mm has a +1 mm lateralization variant) Liners: standard or retentive in +0/+3/+6 mm; +9-mm spacer enables +9/+12/+15-mm buildup standard or retentive in +0/+3/+6 mm +9-mm spacer enables +9/+12/+15-mm buildup Compatibility & Configuration Notes Target radial mismatch between humeral head and glenoid is approximately 3.5–10 mm Eccentric baseplate prohibits use of a central screw Any use of a post extension precludes a central screw 34-mm reverse liners are available only with smaller stem sizes (not for Meta Stem sizes 3–4) Indications Primary anatomic total shoulder arthroplasty using AETOS anatomic glenoid with Meta Stem or Stemless humeral components Reverse shoulder arthroplasty using AETOS reverse baseplate/glenosphere constructs with the AETOS Meta Stem Stemless humeral prosthesis: indicated for anatomic TSA only and not approved for reverse; market availability varies indicated for anatomic TSA only and not approved for reverse market availability varies Anatomy Osteology Anatomic neck: reference for head resection and in-lay collar seating; set inclination and version on this plane reference for head resection and in-lay collar seating set inclination and version on this plane Greater and lesser tuberosities: guide subscapularis approach (LTO/peel/tenotomy) and broach alignment; protect GT during compaction and seating guide subscapularis approach (LTO/peel/tenotomy) and broach alignment protect GT during compaction and seating Glenoid vault and inferior rim: landmarks for pin placement, Angulator reaming trajectory, and baseplate/glenoid seating to reduce inferior impingement landmarks for pin placement, Angulator reaming trajectory, and baseplate/glenoid seating to reduce inferior impingement Muscles Subscapularis management LTO: bony healing surface and robust repair; adds steps for osteotomy and fixation bony healing surface and robust repair adds steps for osteotomy and fixation Peel: preserves tendon footprint; straightforward repair; watch for tendon quality preserves tendon footprint straightforward repair watch for tendon quality Tenotomy: quick exposure; tendon-to-tendon repair; consider length and tissue caliber quick exposure tendon-to-tendon repair consider length and tissue caliber Ligaments Release pattern emphasizes coracohumeral ligament and anterior/inferior capsule; partial preservation of posterior capsule can help centralize the humeral head during trialing emphasizes coracohumeral ligament and anterior/inferior capsule partial preservation of posterior capsule can help centralize the humeral head during trialing Nerves Axillary nerve: at risk with inferior capsular work; use blunt, low-profile retraction hugging the humeral neck at risk with inferior capsular work use blunt, low-profile retraction hugging the humeral neck Musculocutaneous nerve: avoid deep retraction medial to the conjoint tendon when releasing clavipectoral fascia and subcoracoid tissues avoid deep retraction medial to the conjoint tendon when releasing clavipectoral fascia and subcoracoid tissues Blood supply Anterior humeral circumflex vessels encountered at the inferior subscapularis border; coagulate or ligate early to reduce bleeding during inferior capsule release encountered at the inferior subscapularis border coagulate or ligate early to reduce bleeding during inferior capsule release Approach Standard deltopectoral incision centered on the coracoid/anterior shoulder axis Identify the deltopectoral interval and preserve the cephalic vein (lateral mobilization preferred) Release clavipectoral fascia lateral to the conjoint; optional partial release of the superior pectoralis major for exposure optional partial release of the superior pectoralis major for exposure Open the rotator interval and address the biceps (tenotomy or tenodesis per surgeon preference) Nerve cautions: protect axillary inferiorly during releases; maintain awareness of the musculocutaneous nerve near the coracoid/conjoint protect axillary inferiorly during releases maintain awareness of the musculocutaneous nerve near the coracoid/conjoint Technique Common humeral preparation (applies to TSA and RSA) Pre-op templating and beach-chair positioning with head/neck/hip support Pearl: confirm table clearance for Angulator handles and baseplate impactors Exposure and subscapularis management (LTO/peel/tenotomy) Pearl: complete inferior capsule release past the 6-o’clock position to aid safe dislocation Dislocation and osteophyte removal Pearl: circumferential osteophyte removal clarifies the true anatomic neck for an accurate in-lay cut Humeral head resection on the anatomic neck Options: EM cut guide, guided resection jig, or freehand off compactor/template Version holes provided at 0/10/20/30 degrees to accept a version rod Sizing and pin placement Use osteotomy sizers (approx. 38–53 mm range) to cover the cut fully Center a guide pin through the sizer, oriented into the lateral cortex Metaphyseal preparation Cannulated reaming to the stop; avoid over-reaming that reduces cancellous support avoid over-reaming that reduces cancellous support Cruciate broaching with version rod (0/20/30 degrees). A/P fins counter varus–valgus; M/L fins add rotational purchase A/P fins counter varus–valgus M/L fins add rotational purchase Complete fin channels with an osteotome through the broach slot as needed Compaction and protection Stemless path: ST compaction for metaphyseal bed; Meta path: Meta compaction sized 1–4 ST compaction for metaphyseal bed Meta compaction sized 1–4 Place a cut protector/canal cover before glenoid work Compatibility & Configuration Notes Stemless components are for anatomic TSA only and may not be available in all markets Meta Stem supports both TSA and RSA on the same humeral platform Anatomic TSA specifics Humeral head trialing and implantation Aim for full osteotomy coverage; heads ≥44 mm offer two thicknesses for tension adjustment heads ≥44 mm offer two thicknesses for tension adjustment Use a planer if soft-tissue mismatch prevents full taper seating Glenoid preparation with Angulator Size XS–L with optional 5°/10° posterior wedges Central pilot drilling first prevents proud bone; ream with Angulator at 0° for standard or at the selected wedge angle ream with Angulator at 0° for standard or at the selected wedge angle Drill central and peripheral peg holes with keyed guides; trial, lavage, cement pressurization, and controlled seating trial, lavage, cement pressurization, and controlled seating Mismatch guidance Target radial mismatch approximately 3.5–10 mm between humeral head and glenoid size Reverse RSA specifics (Meta Stem only) Baseplate selection and preparation Centered, eccentric, or 10°/15° full-wedge options Place guide pin at the inferior rim; pilot drill; Angulator ream at 0°, 10°, or 15° per implant choice Angulator ream at 0°, 10°, or 15° per implant choice Central fixation rules Central screw is for the centered baseplate only Do not use a central screw with an eccentric baseplate or when a post extension is implanted Peripheral screw strategy Use variable-angle screws; compress first, then lock compress first, then lock Superior and inferior holes must be locking Glenosphere handling Peripheral ream for clearance when needed Ensure clean, dry Morse tapers; impact axially, confirm engagement with axial pull and twist impact axially, confirm engagement with axial pull and twist Secure the retention screw using the torque-limiting handle Humeral liners and spacers Liner heights +0/+3/+6 mm; +9-mm spacer enables +9/+12/+15-mm constructs +9-mm spacer enables +9/+12/+15-mm constructs Do not stack a +9-mm liner with a +9-mm spacer 34-mm liner availability is tied to smaller stems only Compatibility & Configuration Notes Cleared combinations are defined to respect ROM and impingement limits AETOS baseplates and 38-mm glenospheres are compatible with TITAN humeral liners in corresponding 38-mm pairings Technical Specifications Humeral Meta Stem Four sizes (1–4) with an in-lay collar geometry for flush seating on the resection Cruciate fins in A/P and M/L planes for metaphyseal stability Lateral curve and tapered distal segment to reduce cortical contact Porous titanium plasma-spray coating for ongrowth Humeral heads Ten concentric options from approximately 38×14 through 53×22 Within each base width, head height adjusts spherical diameter to tune mismatch and soft-tissue tension Anatomic glenoid XS/S/M/L sizes; standard and 5°/10° full-wedge posterior augments standard and 5°/10° full-wedge posterior augments Four pegs with nine longitudinal flutes designed for cement interdigitation Reverse baseplates Centered, eccentric, and 10°/15° full-wedge shapes Central post approximately 9 × 15 mm; optional post extensions 10 or 15 mm (about 8.25-mm diameter) optional post extensions 10 or 15 mm (about 8.25-mm diameter) Porous-coated fixation surfaces Glenospheres 34/38/42-mm diameters in concentric or eccentric variants Lateralization options include +0/+3 mm; 34-mm sphere also available with +1-mm lateralization Reverse liners and spacers Standard or retentive liners in +0/+3/+6 mm +9-mm spacer enables +9/+12/+15-mm buildup Anti-rotation tabs and positive stem lock-in features Compatibility & Configuration Notes Central screw may be used only with a centered baseplate and never with a post extension With a concentric 0-mm glenosphere, construct lateralization is roughly 7–8 mm depending on baseplate wedge selection Key Takeaways In-lay metaphyseal fixation with cruciate fins recenters the humerus and enhances stability Concentric head strategy simplifies sizing while allowing soft-tissue tuning by height Cemented 4-peg anatomic glenoids include posterior full-wedge options at 5° and 10° Angulator standardizes, simplifies, and corrects version during glenoid/baseplate reaming Clear compatibility rules: target 3.5–10-mm mismatch; central screw only with centered baseplate and never with post extensions Reverse configurations cover 34/38/42-mm spheres and liner/spacer stacks up to +15 mm Stemless option is TSA-only and market availability varies