Abstract
Purpose
Arthrodesis is a traditional surgical procedure for treating thumb carpometacarpal
(CMC) osteoarthritis. Previous studies have investigated surgical outcomes, focusing
on the fixation technique, bone union rate, and surgical complications but not on
the postoperative alignment of the thumb CMC joints. Therefore, we aimed to investigate
how thumb fixation alignment affects the surgical outcomes of thumb CMC arthrodesis.
Materials and Methods
Twenty-six patients (28 thumbs) who achieved bone union after arthrodesis with more
than 1-year follow-up were retrospectively analyzed. We measured the radial abduction
and palmar abduction angles and change in thumb length (Δthumb length) on postoperative
radiographs and the first metacarpal rotation angle on postoperative computed tomography.
Moreover, we investigated the 1-year clinical outcomes, including the Disabilities
of Arm, Shoulder, and Hand (DASH) score, Hand20 questionnaire score, visual analog
scale (VAS) score for pain, Δgrip strength, Δpulp pinch, and Δkey pinch strength.
The correlation between the postoperative alignment and clinical outcomes was also
statistically analyzed.
Results
The mean radial abduction, palmar abduction, first metacarpal rotation angles, and
Δthumb length were 20.8 degrees, 34.4 degrees, 109.4 degrees, and −1.8 mm, respectively.
Radial abduction and palmar abduction angles were positively and negatively correlated
with Δgrip strength (r = 0.37 and −0.37), respectively. The first metacarpal rotation angle was positively
correlated with the DASH score (r = 0.51), Hand20 score (r = 0.48), and VAS score for pain (r = 0.42). ΔThumb length had no correlation with clinical outcomes at 1-year follow-up.
Conclusion
Thumb fixation alignment has an impact on the surgical outcomes of thumb CMC arthrodesis.
To obtain a successful outcome, it is important to add slight pronation and avoid
excessively small radial abduction and excessively large palmar abduction.
Keywords
thumb carpometacarpal osteoarthritis - arthrodesis - alignment - surgical outcomes
