Biomechanical investigation of 'figure of 8' flexor tendon repair techniques

Estudo biomecânico in vitro das suturas em “oito” e de Kessler de tendões flexores de porcos

Objetivo Avaliar as propriedades biomecânicas dos pontos de sutura tendinosa em “oito” e de Kessler.

Métodos Tendões flexores dos dedos de membros superiores de porcos foram divididos em dois grupos com suturas triplas centrais em “oito” (seis passagens) e de Kessler (duas passagens) associadas a suturas periféricas contínuas simples, e submetidos a ensaios mecânicos longitudinais contínuos, obtendo-se as propriedades mecânicas de carga máxima e de energia na carga máxima.

Resultados As médias da carga máxima e da energia na carga máxima na sutura em “8” foram de 63,4 N e 217,3 Nmm, respectivamente; na sutura de Kessler, os valores foram de 34,19 N e 100,9 Nmm, respectivamente. A análise estatística indicou que o ponto em “oito” é superior mecanicamente ao ponto de Kessler.

Conclusões Nas condições deste experimento e no tendão flexor de dedo de membro superior de porcos, o triplo ponto em “oito” (seis passagens) é mais resistente do que o ponto de Kessler (duas passagens). O triplo ponto em “oito”, com seis passagens, permite movimentação ativa na reabilitação imediata de reparo de tendão flexor de dedo de membro superior com pouco risco de ruptura ou espaçamento na sutura.

An Exploratory Study Using Semi-Tabular Plate in Zone II Flexor Tendon Repair

Background: This study evaluated the feasibility of using a low-profile titanium (Ti) plate implant, also known as the Ti-button, for Zone II flexor tendon repair. We hypothesize that the use of the Ti-button can distribute the tensile force on the digital flexor tendons to achieve better biomechanical performance.

Methods: Twenty lacerated porcine flexor tendons were randomly divided into two groups and repaired using Ti-button or 6-strand modified Lim-Tsai technique. Ultimate tensile strength, load to 2 mm gap force, and mode of failure were recorded during a single cycle loading test. We also harvested twelve fingers with lacerated flexor digitorum profundus tendons from six fresh-frozen cadaver hands and repaired the tendons using either Ti-button method or modified Lim-Tsai technique. A custom-made bio-friction measurement jig was used to measure the gliding resistance and coefficient of friction of the tendon sheath interface at the A2 pulley.

Results: The ultimate tensile strength, load to 2 mm gap force, stiffness, and gliding resistance of the Ti-button repairs were 101.5 N, 25.7 N, 7.8 N/mm, and 2.2 N respectively. Ti-button repairs had significantly higher ultimate tensile strength and stiffness than the modified Lim-Tsai repair. However, Ti-button also increased the gliding resistance and coefficient of friction but there was no significant difference between the two repair techniques.

Conclusions: Ti-button repair displayed comparable mechanical properties to the traditional repair in terms of 2-mm gap formation and gliding resistance, but with a stronger repair construct. Thus, this deepened our interest to further investigate the potential of using Ti-button implant in Zone II flexor tendon repair by studying both the mechanical and biochemical (tendon healing) properties in more in-depth.

Primary Flexor Tendon Repair with Early Active Motion: Experience in Europe

The protocol for primary flexor tendon repair in zones 1 and 2 of the hand is changing. This article discusses recent changes. Immediate repair within 48 hours is performed whenever possible. A 6-strand core suture is performed using the M modification of Tang's technique. The pulleys are divided to allow free excursion of the repaired tendon within the tendon sheath. To avoid repaired structures within the sheath being too bulky, the authors generally repair only half of the flexor digitorum superficialis. In some cases, the flexor digitorum superficialis is excised completely. Rehabilitation remains based on controlled active motion.

Strong Digital Flexor Tendon Repair, Extension-Flexion Test, and Early Active Flexion: Experience in 300 Tendons

Over the past 2 decades, repair and rehabilitation methods of primary repair of the digital flexor tendon have changed. In this article, we outline interim results from ongoing investigations in several units. Surgeons in these units now perform digital flexor tendon repairs according to a treatment protocol. Before adopting the protocol, they had no history of tendon-related research; they had not used any of the repair and rehabilitation methods described in the protocol. The surgeons involved are junior or midlevel attending surgeons. At the end of this article, we outline current practice of digital flexor tendon repair in Asian countries.