The consequence of permanent instability due to pseudoarthrosis of the scaphoid is devastating. The mobile, often tilted bone fragments lead to the rubbing of the joint surfaces against each other, which over the course of years causes irreversible joint damage and ultimately leads to wrist osteoarthritis.
Stages of Osteoarthritis
The stages of osteoarthritis are categorized according to severity and cause. These are SNAC-Wrist I-III as consequence of an untreated pseudoarthrosis of the scaphoid. The abbreviation SNAC stands for Scaphoid Non-union Advanced Collapse. If there are consequences of ligament ruptures between the scaphoid and lunate, then this is abbreviated as SLAC, which stands for Scapholunate Advanced Collapse and is also categorized in 3 stages (SLAC-Wrist I-III). The corresponding required operative correction depends on the severity. In stages II and III, any reconstructive measures to the ligament or scaphoid are no longer sensible. Therefore, in a procedure called “four-corner-fusion”, the scaphoid is removed and the wrist is partially fused. This movement-maintaining method in SNAC/SLAC-Wrist stages II and III is preferable over other methods of wrist fusion. A further alternative in these stages is the so-called “proximal row carpectomy”, in which the complete first row of carpal bones are removed and a new joint created.
More on scaphoid fractures and their consequences in
Hand Surgery at a Glance