Reconstructive surgery of the upper limb was performed in an attempt to restore dynamic motor balance in 55 patients with adult-acquired spastic hemiplegia. An eight-level grading system was developed to determine the level of functional capacity. Because this system proved useful in predicting the results of surgery, it was utilized for operative planning. A two-level increase in functional grade was necessary for patients to obtain a meaningful increase in function. The average improvement after surgery was 2.10 functional levels. A two-level increase was achieved in 73.2% of the patients. No patient decreased in grade, and only one remained unchanged. In selected patients with upper limb spasticity, a predictable improvement in functional capacity can be obtained with dynamic motor balancing surgery.