Multiplanar wrist joint proprioception: The effect of anesthetic blockade of the posterior interosseous nerve or skin envelope surrounding the joint.

STUDY DESIGN Randomized clinical trial. PURPOSE Contribution of the posterior interosseous nerve (PIN) and surrounding skin envelope to wrist proprioception is a topic of debate and the primary focus of this research. METHODS We performed a double-blinded, placebo control study in which subjects underwent baseline multiplanar testing of wrist proprioception. They were randomized to receive either anesthetic blockade of the PIN within the fourth dorsal compartment, or circumferential topical anesthetic blockade of skin surrounding the wrist. Corresponding opposite wrists underwent placebo intervention with saline injection or inert ultrasound gel. Subjects repeated proprioceptive testing. RESULTS Eighty subjects, 45 male and 35 female, mean age 33 years (range, 19-64 years), completed testing. The percentage of measurements falling outside a ±18° range did not differ between pre-treatment and post-treatment PIN blockade or for circumferential skin anesthesia. CONCLUSIONS Wrist proprioception appears to be a multifactorial phenomenon. Surgeons may sacrifice the PIN without concern for effect on joint proprioception. LEVEL OF EVIDENCE Level I.