Anatomical study of the ligamentous attachments and articular surfaces of the trapeziometacarpal joint. Consequences on surgical management of its osteoarthrosis.

In the goal to optimize conservative surgical techniques of the trapeziometacarpal joint in cases of moderate osteoarthritis, we have defined the relationships between the ligamentous attachments and the articular surfaces onto the trapezium and the first metacarpal bone on the one hand, and the dorsovolar and the transverse diameters of the articular surfaces on the other hand. Thirty-six trapeziometacarpal joints (from 18 fresh cadavers) were studied. They were separated into two groups depending on the macroscopic assessment of chondral disease. Group A included stages I to III (no osteoarthritis or moderate osteoarthritis), group B included stages IV (major cartilage destruction). The dorsovolar and transverse sizes of the articular surfaces were measured. Dorsoradial ligament (DRL), posterior oblique ligament (POL), intermetacarpal ligament (IML), ulnar collateral ligament (UCL) and anterior oblique ligament (AOL) were dissected and the distance between their attachments and the articular surfaces were measured. Group A included 17 joints (71% males) and group B included 19 joints (95% females). For the first metacarpal bone, the average ratio between the dorsovolar diameter and the transverse diameter of metacarpal articular surfaces was significantly higher in group B and the average distance between the ligamentous attachments and the articular surface was more than two millimeters, except for the DRL in group B. For the trapezium, only the posterior ligaments (DRL and POL) of group A were inserted at a mean distance more than two millimeters from the articular surfaces. Dorsovolar length of the metacarpal articular surface was higher for osteoarthritis cases. This difference can be explained by the existence of a palmar osteophyte that was always found in stage IV. Describing a map of the ligamentous attachment distance from the articular surface could help surgeons to avoid the ligamentous injury during minimal osteochondral resection.