MSS - Monobloc stem

The MSS – Monobloc stem is a shoulder prosthesis component for treating humeral fractures and primary or revision shoulder replacement in patients with rotator cuff deficiency. It is available in both standard and short versions, made of titanium alloys (Ti6Al7Nb with Ti+HA coating or Ti6Al4V via additive manufacturing), intended for cementless fixation with optional cortical bone screws.

The device features monobloc stem design with 11 sizes, stem lengths and coated area that differ from predicates but remain within predicate ranges. Key differences include varied suture hole positions, tabs on humeral reverse liners (vs. pegs), small metaphysis diameter, two spacer/double eccenter sizes, and new 3D metal short stem and E-Cross liner materials. Similarities include stem fixation method, liner inclination, articular surface diameter, jump height, coating, biocompatibility, sterilization, and shelf-life.

ASTM F1378-18e1 for range of motion assessment; European Pharmacopoeia §2.6.14 for bacterial endotoxin testing (equivalent to USP <85>); USP chapter <151> for pyrogenicity testing.

Substantial equivalence is established because the device shares monobloc stem design and key technological features with multiple predicates (K170452, K170910, K180089, K210207, K223801, K213117, K212737, K130759). Device differences (stem lengths, coating area, suture holes, liner coupling, metaphysis diameter, new materials) do not raise different safety or effectiveness questions, as they remain within predicate ranges or use previously cleared materials and manufacturing processes (per K202568 and K202022). Non-clinical testing validates mechanical integrity, fatigue resistance, and biocompatibility.