Scientific article
Analysis of a Knotless Flexor Tendon Repair Using a Multifilament Stainless Steel Cable-Crimp System

https://doi.org/10.1016/j.jhsa.2013.01.018Get rights and content

Purpose

To compare the biomechanical and technical properties of flexor tendon repairs using a 4-strand cruciate FiberWire (FW) repair and a 2-strand multifilament stainless steel (MFSS) single cross-lock cable-crimp system.

Methods

Eight tests were conducted for each type of repair using cadaver hand flexor digitorum profundus tendons. We measured the required surgical exposure, repair time, and force of flexion (friction) with a custom motor system with an inline load cell and measured ultimate tensile strength (UTS) and 2-mm gap force on a servo-hydraulic testing machine.

Results

Repair time averaged less than 7 minutes for the 2-strand MFSS cable crimp repairs and 12 minutes for the FW repairs. The FW repair was performed with 2 cm of exposure and removal of the C-1 and A-3 pulleys. The C-1 and A-3 pulleys were retained in each of the MFSS cable crimp repairs with less than 1 cm of exposure. Following the FW repair, the average increase in friction was 89% compared with an average of 53% for the MFSS repairs. Six of the 8 MFSS specimens achieved the UTS before any gap had occurred, whereas all of the FW repairs had more than 2 mm of gap before the UTS, indicating that the MFSS was a stiffer repair. The average UTS appeared similar for both groups.

Conclusions

We describe a 2-strand multifilament stainless steel single cross-lock cable crimp flexor repair system. In our studies of this cable crimp system, we found that surgical exposure, average repair times, and friction were reduced compared to the traditional 4-strand cruciate FW repair. While demonstrating these benefits, the crimp repair also produced a stiff construct and high UTS and 2-mm gap force.

Clinical relevance

A cable crimp flexor tendon repair may offer an attractive alternative to current repair methods. The benefits may be important especially for flexor tendon repair in zone 2 or for the repair of multiple tendons.

Section snippets

Materials and Methods

We compared the parameters of the MFSS cable-crimp repair with a 4-strand cruciate FW repair. We measured the force of flexion of the intact tendon and then measured the force of flexion following repair. The percent change in this force was then calculated. We also measured the ultimate load and load at 2-mm gap,17, 27, 28, 29, 30, 31, 32, 33, 34, 35 which likely correlates with clinical performance.1, 16 We measured the time for the tendon repair and measured the length of surgical exposure

Repair time

The repair time for tendon repairs averaged 12 minutes for the 4-strand cruciate FW repair and less than 7 minutes for the 2-strand MFSS cable crimp repair.

Surgical exposure

The surgical exposure for the FW repair averaged 2.1 cm. The average exposure for the MFSS was 0.6 cm. All FW repairs required resection of C1 and A3 pulleys. Pulleys were retained in all 2-strand MFSS repairs.

Force of flexion, ultimate tensile strength, and 2-mm gap force

The force of flexion measured 89 ± 35% and 53 ± 18% for the 4-strand cruciate FW repair and 2-strand MFSS cable crimp repair,

Discussion

Despite advances in flexor tendon repair and identification of factors that affect the outcome of these repairs, there remains a need for a repair that is simple and fast and results in a strong, stiff construct.6, 8, 36 In this study, we report on a 2-strand cable crimp repair with a 3-0 MFSS cable that satisfies these criteria. This repair uses a single cross-lock stitch, requires minimal surgical exposure, and requires approximately half the surgical time to complete the repair when compared

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    The authors thank Blane Uthman for his invaluable technical support during the entire testing and experimental process.

    Funding for this research was provided by Pontis Orthopaedics. L.G. owns stock in Pontis Orthopaedics. J.G. is an immediate family member of L.G.

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