gms | German Medical Science

Objectives/Interrogation: Dorsal intercalated segment instability (DISI) is problematic, complicated wrist disorder which cause great disturbances in patients everyday living, work and sports activities. Because of pain patients often diminish wrist ROM and function which indicates even more imbalance. In ligamentous DISI cases proper operative or non-operative treatment is crucial for patients recovery. Despite the fact that the medicine know more and more about proprioception and its influence to the wrist stability it is still a great challenge to objectively assess its activation in wrist motion and stability.

Methods: 18 patients with ligamentous DISI (age: 32 y.o) and 20 volunteers as a control group underwent wrist isotonic examination on Biodex System 4 Pro and joint position sense examination on Three Dimensional Upper Limb Movement Zebris System HAF. The examination was concerned with the basic wrist movements: flexion and extension, adduction, abduction and with retrieving the "0" position (the one line with the forearm). For the research the method of assisted presentation and active reproduction was taken.

Results and Conclusions: There was significant difference (p<0,05) between DISI wrist flexors and extensors biomechanical parameters in comparison to the healthy wrist and control group. Wrist and fingers extensors average peak velocity was 308,2 deg/sec and wrist and fingers flexors average peak velocity was 405,7 deg/sec. The agonist antagonist ratio in DISI wrist was 72%, healthy wrist 58% and control group 57%. There were no significant difference in EARJP (error of active reproduction of joint position sense) between DISI group and control group. EARJP for wrist extension was 3,7 ± 1,9 deg in DISI wrist and in control group 3,1 ± 2,4 deg.

Disabled ligamentous stabilization is supported by higher forearm muscles activation. Decreased level of forearm muscles biomechanical parameters is responsible for increased error of active reproduction.