Functional sequelae after ulnar nerve repair. Study of forty-nine cases

The full picture of functional ulnar deficiency, following suture or grafting, was studied and analyzed by two of the authors, who followed this series of patients on a long-term basis. The patients were tested using sphygmometric rubber bulbs in other to determine the overall closing force of the hand (making a fist), and the force of the pinch between the thumb and index ("energetic pinch"). Moreover, radionuclide vascular tests were used in order to find an eventual etiology of the "cold" disease, present in 2/3 of these injured hands. The principal functional deficiencies which bothered the patients and which we were able to demonstrate are as follows: deficient adduction of the thumb: the pinch between the thumb and index is diminished by approximately 50%, impairment, in the spreading of fingers, impairment in the overall force of the grasp, ulnar clawing which may embarrass function of the hand one year after the operation in one fourth of the cases. Therefore it appeared logical to propose an adduction plasty at the same time of repair, whether it was a primary suture or a secondary nerve graft. This adduction plasty uses the flexor digitorum sublimis of the ring finger which is rerouted and passed behind the profondus tendons and brought over to the lateral sesamoid bone of the thumb. This transfer is prolonged and tacked to the extensor pollicis longus in order to prevent the hyperflexion of the proximal phalanx of the thumb of which patients hardly ever complain but which denotes the severeness of ulnar nerve injury. An excellent correlation exists between the severeness of the functional deficiency and the importance of Froment's sign. The study of the other residual deficiencies shows that the restoration of the first dorsal interosseus, the reinforcement of the force of the flexores digitorum profundus of the middle and fourth fingers and of the intrinsics does not seem to be justified on an emergency basis. Zancolli's operation, which has been advocated by certain authors as an emergency procedure, does not seem to be necessary at this stage of repair, but remains a very interesting palliative procedure one year after the nerve repair if still judged necessary. Several clinical examples illustrate the value of long-term follow-up of these operated patients.