Proximal interphalangeal joint injection through a volar approach: anatomic feasibility and cadaveric assessment of success.

Purpose: The proximal interphalangeal (PIP) joint is a challenging joint to access reliably for corticosteroid injection. Literature has confirmed both a relatively high failure rate for injections performed with the traditional dorsal approach and an improved clinical response rate for confirmed intra-articular injections. We describe a technique for injecting the PIP joint through a volar approach, assess its reliability through cadaveric dissection, and determine its reproducibility by comparing success rates with the dorsal approach in a cadaver model.

Methods: We dissected the PIP joint of 10 cadaveric digits to document necessary anatomic landmarks for this technique. We then used 20 matched pairs of cadaver hands for the remainder of our study. Four PIP joints on each hand (thumb excluded) were injected with a solution of saline and radio-opaque dye using the dorsal approach. We injected each joint on the contralateral matched hand through the volar approach. We obtained standardized fluoroscopic images of each joint immediately after injection, which were reviewed by an independent observer who was blinded to the technique and who rated outcomes as success, failure, or mixed. Success rates were evaluated based on approach used, digit injected, and degree of pre-existing arthritis.

Results: We found reproducible anatomic landmarks that justified our injection technique. The rates of absolute failure were similar in the 2 cohorts. The volar approach demonstrated a higher percentage of successful injections with a smaller percentage of mixed results, although results did not reach statistical significance. There was no statistically significant difference in success rates based on digit injected or grade of arthritis in either cohort.

Conclusions: The volar approach to injecting the PIP joint demonstrated success similar to that of the traditional dorsal approach. Reproducible surface landmarks exist to guide practitioners using this technique. Further study is needed to determine the potential complications and clinical outcomes of the volar approach.

Type Of Study/level Of Evidence: Therapeutic IV.