This review examines whether glenoid version, traditionally measured relative to the scapular body, is the right reference for placing a glenoid component in total shoulder arthroplasty. It integrates scapular embryology, genetics, and congenital/neuromuscular conditions to question that assumption. The authors propose that muscular balance and a stable articular platform matter more than restoring an average version value.
When you plan a glenoid component, the reflex is to restore version toward the normal ~2° anteversion using eccentric reaming or posterior grafting.
This paper asks whether that reference frame is even valid. The glenoid and scapular body come from different embryologic tissues under separate genetic control (Hoxc6 vs Emx2), so version relative to the body varies widely and may not reflect the true biomechanical axis.
The strongest clinical clue comes from posterior subluxation: correcting the bony version with osteotomy did not re-center the humeral head, so soft-tissue balance dominates. Brachial plexus birth palsy reinforces this, where muscular imbalance, not intrinsic bone disease, drives glenoid retroversion.
The takeaway for the OR is to prioritize muscular balance and a stable, well-supported articular surface within the available vault bone rather than chasing a single average version number. Remember the evidence level: this is a review synthesizing prior small series, so it reframes thinking rather than dictating a protocol.
This review examines whether glenoid version, traditionally measured relative to the scapular body, is the right reference for placing a glenoid component in total shoulder arthroplasty. It integrates scapular embryology, genetics, and congenital/neuromuscular conditions to question that assumption. The authors propose that muscular balance and a stable articular platform matter more than restoring an average version value.
When you plan a glenoid component, the reflex is to restore version toward the normal ~2° anteversion using eccentric reaming or posterior grafting.
This paper asks whether that reference frame is even valid. The glenoid and scapular body come from different embryologic tissues under separate genetic control (Hoxc6 vs Emx2), so version relative to the body varies widely and may not reflect the true biomechanical axis.
The strongest clinical clue comes from posterior subluxation: correcting the bony version with osteotomy did not re-center the humeral head, so soft-tissue balance dominates. Brachial plexus birth palsy reinforces this, where muscular imbalance, not intrinsic bone disease, drives glenoid retroversion.
The takeaway for the OR is to prioritize muscular balance and a stable, well-supported articular surface within the available vault bone rather than chasing a single average version number. Remember the evidence level: this is a review synthesizing prior small series, so it reframes thinking rather than dictating a protocol.