Experimental study of the consequences of resection of the flexor retinaculum on the stability of the scaphoids

To analyze the consequences of flexor retinaculum (FR) section on the kinetic behavior of the scaphoid, triquetrum and capitate bones under axial load. Material and method: A 6 degree-of-freedom electromagnetic motion tracking device with sensors attached to the scaphoid, triquetrumcapitate and radius was used to monitor spatial changes in carpal bone alignment as a result of isometrically loading the main motor writs muscles. Six wrists from fresh cadavers were used, in which the principal motor tendons were subjected to loads proportional to physiological cross sectional area of each muscle. The experiment was carried out with the wrist in the neutral position, before and after the FR section. Results: After FR section, the scaphoid showed less flexion (P = .05) and a higher degree of radial inclination (P = .03) compared to the same experiment with the FR intact. The kinetic behavior of the triquetrum did not change significantly. Discussion: According to the results of this study, the isolated section of the FR did not produce greater instability of the scaphoid. If so, the scaphoid should have a higher degree of flexion, but exactly the opposite movement happens. Conclusion: Resection of the FR alters the kinetic behavior of the scaphoid under axial load, but does not produce greater instability in the carpus. Pillar syndrome may not be as a result of scaphoid instability, but due to another type of dysfunction that needs to be determined in future studies. © 2010 SECOT.