Thumb deformity in the spastic hand: classification and surgical techniques

Surgery based on an accurate determination of deforming forces, muscle weakness, and joint instability achieves reasonably predictable results in patients with cerebral palsy. Thumb deformities can be classified into those of mainly intrinsic nature, extrinsic nature, and those of a combined nature. This allows identification of which muscles are released most appropriately and which muscle function requires augmentation. Joint instability needs to be taken into consideration because tendon transfers across unstable joints will be ineffective. The various surgical procedures are outlined in the text. In 32 patients, application of these principles and techniques allowed removal of the thumb from the palm in 29 patients during fist formation. Lateral pinch was established in 26 thumbs, and functional assessment revealed improvement in one functional grade. Functional benefit may be determined by other factors beyond the control of the surgeon. Therefore, the decision to proceed to surgery may be undertaken only after detailed and repeated clinical examinations are conducted that are coordinated with the assessments of parents, caregivers, physicians, occupational and physical therapists, and social counselors.