Background: Gap formation is a common complication after flexor
tendon repair and is associated with adhesion formation, tendon rupture, and
decreased strength. The purpose of this study was to investigate the effect of
gap formation on tendon gliding resistance after flexor tendon repair in a
human cadaver model.
Methods: Twelve index, middle, and ring fingers from four adult
human cadaveric hands were used. Gliding resistance versus excursion between
the flexor digitorum profundus tendon and the A2 pulley was first measured in
intact tendons. After full laceration, each tendon was repaired with the
Pennington suture technique and the gliding resistance was measured again.
Then, the repaired tendon (a 0-mm gap) was stretched to form a 1-mm gap, and
gliding resistance was remeasured. A magnified video image was used to monitor
gap size. This process was repeated to evaluate gap sizes of 2, 3, and 4 mm at
the repair site. Peak gliding resistance was determined, and the peak gliding
resistance was compared among the groups.
Results: No significant difference in peak gliding resistance was
detected between repaired tendons without a gap and tendons with a 1-mm gap.
Repaired tendons with a 2-mm gap could pass through the A2 pulley; however,
peak gliding resistance was significantly higher than that for tendons with a
0 or a 1-mm gap (p < 0.05). When the gap reached =3 mm, all tendons
caught at the A2 pulley edge, causing a dramatically increased peak gliding
Conclusions: The presence of a 2-mm gap after flexor tendon repair
significantly increased tendon peak gliding resistance (p < 0.05), while a
gap of =3 mm further increased peak gliding resistance because of catching
at the pulley edge.
Clinical Relevance: This study suggests that a large gap (=3 mm)
that develops after repair of the flexor digitorum profundus tendon may
increase the risk of triggering (catching) at the pulley edge, which may
predispose the tendon to rupture, limitation of motion, or adhesion formation
during postoperative rehabilitation. Therefore, we believe that minimizing gap
formation is an important consideration in flexor tendon repair.