TREATMENT OF EATON STAGE I TRAPEZIOMETACARPAL DISEASE

Abstract

Although the cause of TM joint hypermobility may be multifactorial, translational laxity and instability appear to be related to degeneration of the beak ligament. Indeed, the forces experienced at the normal TM joint with grip and pinch are magnified several fold and are concentrated in the palmar aspect of the joint. The TM stress test used in preoperative assessment of thumbs with hypermobile TM joints reflects nonphysiologic dorsal translation and correlates with histologic evidence of detachment of the metacarpal origin of the beak ligament. Ligament reconstruction of the painful TM joint reflects the importance of the beak ligament in providing stability and in limiting dorsal translation of the metacarpal that normally occurs during dynamic pinch activity. Metacarpal extension osteotomy, by contrast, shifts mechanical loading at the TM joint more dorsally and redirects force vectors. Its precise role in the treatment of TM disease has long remained ill-defined because of a lack of correlation between preoperative disease status and postoperative functional result. It appears now, however, that for stage I disease, metacarpal extension osteotomy may result in satisfactory pain relief and improved grip and pinch strength--at least in the short term. Indeed, extension osteotomy may be an efficacious alternative to ligament reconstruction, but long-term follow-up and additional clinical studies will be helpful in shedding additional light on this topic.