Comment on “Partial Denervation of the Thumb Carpometacarpal Joint: A New Technique”

We have read with interest the article by Hayman Lui and Sanjeev Kakar, ¹ Partial Denervation of the Thumb Carpometacarpal Joint: A New Technique, and would like to offer several observations.

Inclusion of patients with scaphotrapeziotrapezoid (STT) osteoarthrosis would be expected to worsen outcomes, especially if preoperatively symptomatic. In our experience, a positive modified Watson sign—crepitus and pain elicited when the examiner supports the distal pole of the scaphoid—is a reliable indicator of clinical STT involvement. In our experience, when this sign is present, denervation of the carpometacarpal (CMC) joint alone is often insufficient and requires additional procedures such as posterior interosseous neurectomy (PIN)/anterior interosseous neurectomy, neurectomy of the Cruveilhier branches, or even formal sympathectomy of the distal branches of radial artery to comprehensively address nociceptive input from these structures. The study does not clarify whether any patients had clinically meaningful STT arthritis or whether the STT joint shares identical innervation with the CMC joint, both of which merit further elucidation.

The authors’ anatomical assumptions are based on a single study by Miki et al, ² whereas multiple anatomical studies have addressed CMC joint innervation. While contributions from the radial nerve and lateral antebrachial cutaneous nerve are undisputed, reports vary regarding median and ulnar nerve involvement. Miki et al observed no contribution from the palmar cutaneous branch of the median nerve, with all median nerve fibers originating from its motor branch. In contrast, other studies report palmar branch involvement in up to 70% of cases, raising the possibility of population-specific variation or differing interpretations. Notably, Miki et al found palmar-ulnar capsule innervation from a deep branch of the ulnar nerve—a finding at odds with some anatomical studies, ³ though indeed possible PIN involvement via the deep ulnar branch has been proposed. ⁴ The surgical technique described is similar to that of Dellon and others using the Wagner approach with thenar muscle elevation from the CMC joint capsule. However, in view of all above mentioned, it remains uncertain whether ulnar nerve branches were truly sectioned; this appears to be an assumption. In addition, such wide exposure may risk painful scarring.

Ultimately, despite detailed anatomical works, the central question remains unanswered: how do the branches identified in cadaveric studies actually contribute to clinical pain? Given the potential advantages of denervation, further studies integrating anatomical and clinical data are warranted.

We appreciate the opportunity to comment on this important topic.