Alternate Graft Options for Staged Flexor Tendon Reconstruction: A Cadaveric Study of Hamstring Autografts Compared to Conventional Autografts.

PURPOSE: To compare the semitendinosus and gracilis tendon lengths and diameters to the palmaris longus, plantaris, flexor digitorum profundus, and flexor pollicis longus (FPL) tendons in a cadaveric model to evaluate the feasibility of hamstring autograft use for staged flexor tendon reconstruction. METHODS: Fifteen fresh cadavers were evaluated for surgical incisions about the knee, forearm, and hand. All flexor digitorum profundus (FDP), FPL, palmaris longus, plantaris, semitendinosus, and gracilis tendons were harvested from each specimen. Diameter and length were recorded and means with SDs were calculated. The mean diameters of the gracilis and semitendinosus were compared to the mean diameters of the FDP and FPL tendons. The hamstring tendon lengths were then compared in terms of percentage of the palmaris longus and plantaris tendon lengths. RESULTS: The gracilis (18.0 cm) and semitendinosus (19.9 cm) means were notably longer than the palmaris longus (16.0 cm) and shorter than the plantaris (30.0 cm). The average gracilis tendon diameter (3.8 mm) was smaller than the flexor tendon diameters except for the little finger FDP (3.8 mm). The semitendinosus tendon diameter (4.8 mm) was larger than all flexor tendons with the exception of the middle finger FDP (4.6 mm). Average gracilis and semitendinosus tendon diameters were 3.7 mm and 4.5 mm in males, and 3.8 mm and 4.8 mm in females. CONCLUSIONS: This study showed the gracilis tendon to have adequate length and diameter for potential autograft use in staged flexor tendon reconstruction in all digits but the little finger. The semitendinosus is larger in diameter than the native flexor tendons, making it a poor autograft option in cases with an intact pulley system. CLINICAL RELEVANCE: Common tendon autograft options for flexor tendon reconstruction are variably present, and the use of gracilis and semitendinosus autograft present potential graft options.

Analysis of simple sequence repeat (SSR) structure and sequence within Epichloë endophyte genomes reveals impacts on gene structure and insights into ancestral hybridization events.

Epichloë grass endophytes comprise a group of filamentous fungi of both sexual and asexual species. Known for the beneficial characteristics they endow upon their grass hosts, the identification of these endophyte species has been of great interest agronomically and scientifically. The use of simple sequence repeat loci and the variation in repeat elements has been used to rapidly identify endophyte species and strains, however, little is known of how the structure of repeat elements changes between species and strains, and where these repeat elements are located in the fungal genome. We report on an in-depth analysis of the structure and genomic location of the simple sequence repeat locus B10, commonly used for Epichloë endophyte species identification. The B10 repeat was found to be located within an exon of a putative bZIP transcription factor, suggesting possible impacts on polypeptide sequence and thus protein function. Analysis of this repeat in the asexual endophyte hybrid Epichloë uncinata revealed that the structure of B10 alleles reflects the ancestral species that hybridized to give rise to this species. Understanding the structure and sequence of these simple sequence repeats provides a useful set of tools for readily distinguishing strains and for gaining insights into the ancestral species that have undergone hybridization events.