Purpose
The flexor digitorum superficialis tendon to the little finger (FDS-5) has been observed
to have a higher degree of functional and structural variation than the FDS of other
digits. FDS-5-deficient individuals necessarily rely on the flexor digitorum profundus
tendon to the little finger (FDP-5) for flexion in their little fingers. FDS-5 deficient
patients who experience a considerable injury to their FDP-5 are therefore at a risk
of losing substantial little finger flexion. The purpose of this study was to evaluate
the degree of flexion of the little finger at the metacarpophalangeal and proximal
interphalangeal (PIP) joints in a cadaveric model of FDS-5 deficiency following amputation
of the distal phalanx.
Methods
Ten fresh-frozen cadaveric upper extremities with no prior trauma were used. Loads
were applied to the FDP-5. Flexion at the PIP and metacarpophalangeal joints was measured
in degrees with a goniometer. Little finger flexion testing was conducted under 5
different conditions: “baseline,” “FDS-deficient,” “no repair,” “bone anchor” repair,
and “A4 pulley” repair.
Results
The results were as follows: (1) no significant differences in the flexion between
baseline and FDS-deficient conditions; (2) a significant decline in PIP flexion in
the no repair condition after FDP-5 division compared with the FDS-deficient condition;
(3) a significant restoration in PIP flexion in both surgical repair groups compared
with the no repair group; and (4) no significant differences in PIP flexion between
the A4 pulley and bone anchor groups.
Conclusions
The bone anchor repair and the A4 pulley repair demonstrate similar abilities to restore
flexion of the little finger at the PIP joint to baseline levels in this cadaveric
model.
Clinical relevance
A clinical protocol is yet to be established for the surgical treatment in FDS-5-deficient
patients requiring amputation of the distal phalanx of the little finger. This study
aims to address this area of uncertainty by comparing the little finger flexion after
2 different approaches to profundus tendon reattachment that may be applicable in
this clinical scenario.
Key words
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Article info
Publication history
Published online: November 06, 2021
Accepted:
July 14,
2021
Received:
September 11,
2020
Footnotes
Z.L.B. and J.D.K. contributed equally to this work.
No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.
Identification
Copyright
© 2022 by the American Society for Surgery of the Hand. All rights reserved.
