Outcomes and Complications of Tendon Transfers to Address Pinch and Grasp Weakness: A Systematic Review of the Operative Management of Ulnar Nerve Paralysis

Background Patients with ulnar nerve paralysis note difficulties performing activities of daily living because of weakness of pinch and altered grasp mechanism. This review investigates outcomes of tendon transfers for ulnar nerve paralysis to assist in shared decision-making with patients during preoperative counseling and to inform operative choices. Methods A systematic review was conducted to identify studies reporting outcomes following tendon transfer for ulnar nerve palsy. Studies were screened according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and inclusion and exclusion criteria were applied. Primary outcome measures included postoperative pinch strength and mechanism of grasp. Results A total of 26 studies (687 patients) met criteria for inclusion. After pooled analysis, the flexor digitorum superficialis lasso procedure yielded the highest rate of complete correction of claw deformity (60.6 percent), followed by flexor digitorum superficialis four-tail operation (31.4 percent). The extensor carpi radialis longus four-tail operation yielded the greatest improvement in grip strength (3.8 kg). The extensor carpi radialis brevis four-tail operation resulted in the best open hand assessment and mechanism of closing scores; however, these studies did not objectively evaluate grip strength. The greatest increase in pinch strength was following tendon transfer to adductor pollicis alone. Conclusions Despite the heterogeneous data, if the primary goal is improvement in the appearance of claw deformity, the evidence supports flexor digitorum superficialis lasso transfer. However, if the primary concern is grip strength, the data favor extensor carpi radialis longus four-tail transfer. When pinch strength is functionally limiting, adductorplasty alone is most effective. These data will assist providers in appropriately informing patients of common risks and complications and setting realistic expectations following tendon transfer procedures.