Kinematic analysis of hand movements after tendon repair surgery: a new assessment using drawing movements.

OBJECTIVE Although several hand outcome tests exist to judge skill level after hand injury, currently none give insight into how tasks are performed by looking at kinematic parameters. In this article, the clinical value of analyzing kinematic parameters related to the drawing of a triangle on a graphics tablet by healthy subjects and patients with hand injury is discussed. DESIGN In a first experiment 10 healthy subjects drew the triangles as accurately as possible at various speeds. In a second experiment, 67 healthy subjects and 12 patients with flexor tendon injury were measured repeatedly. RESULTS In the first experiment, the analysis showed a high linear correlation between speed and accuracy for each individual (Pearson correlation coefficient >/=0.762, P </= 0.01). The data led to a formula to standardize deviation for drawing speed, so that different measurements can be compared. In the second experiment, these two measurements correlated well (Pearson correlation coefficient = 0.909, P < 0.001), although a learning effect was noticed (5.4% improvement on average). In healthy subjects the dominant hand performed significantly better than the nondominant hand (P < 0.001). Patients performed significantly worse with their injured hand after 6 wks of dynamic splinting than did healthy subjects (P = 0.003). With their uninjured hand, they performed better than the controls. Six weeks after removal of the splint, no kinematic differences could be discovered between patients and controls. CONCLUSION The results show that kinematic parameters of hand movements may be of additional value for assessing functional recovery from hand injury.