Role of collateral ligaments in metatarsophalangeal stability: a cadaver study.
BACKGROUND
Lesser metatarsophalangeal joint (MTPJ) instability is a common complaint. The role each of the collateral structures play in maintaining joint stability is unknown.


METHODS
Twenty-six fresh-frozen cadaver lesser MTPJ's were tested for instability with the amount of force necessary to translate the joint 3 mm dorsally. Specimens were tested with 1) intact collateral ligaments, 2) transected accessory collateral or proper collateral ligaments (ACL or PCL), 3) repaired ACL or PCL, 4) transected ACL and PCL, 5) repaired ACL and PCL, and 6) transferred interosseous (IO) tendon. Student t-tests were performed to test for statistical significance (p value less than 0.05).


RESULTS
The mean force required for 3 mm of dorsal displacement was 25 ± 13 N (range, 11 to 52 N) in the 26 specimens. Transecting either the ACL alone or the ACL and PCL led to the most instability versus transecting the PCL alone. Repairing both ligaments improved stability. The IO tendon transfer was comparable to the direct repair of the PCL but was inferior to the direct repair of the ACL.


CONCLUSIONS
Both ACL and PCL have a stabilizing effect on the MTPJ. However, the ACL was more important since primary transection of the ACL led to more instability and additional transection of the PCL in an ACL deficient model did not lead to significantly more instability.


CONCLUSIONS
Direct repairs of both structures improved the stability of the joint but not back to normal. IO tendon transfer is a possible adjunct to collateral ligament repairs, but in itself is not sufficient to restore stability.
University of Utah, Orthopaedics, Salt Lake City, UT 84108, USA.
Alexej
A
Barg
Xan F
XF
Courville
Florian
F
Nickisch
Kent N
KN
Bachus
Charles L
CL
Saltzman
D000328:Adult; D002102:Cadaver; D017885:Collateral Ligaments / Q000033:anatomy & histology / Q000293:injuries / Q000502:physiology* / Q000601:surgery; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D008683:Metatarsophalangeal Joint / Q000502:physiology*; D008875:Middle Aged; D013709:Tendon Transfer; D016474:Weight-Bearing / Q000502:physiology