Research Article Four-Strand Core Suture Improves Flexor Tendon Repair Compared to Two-Strand Technique in a Rabbit Model Alice Wichelhaus, 1 Sascha Tobias Beyersdoerfer, 1 Brigitte Vollmar, 2 Thomas Mittlmeier, 1 and Philip Gierer 1 1 Abteilung f¨ ur Unfall-, Hand- und Wiederherstellungschirurgie, Chirurgische Universit¨ atsklinik Rostock, Schillingallee 35, 18055 Rostock, Germany 2 Rudolf-Zenker-Institut f¨ ur Experimentelle Chirurgie und Zentrale Versuchstierhaltung, Universit¨ atsmedizin Rostock, Schillingallee 69a, 18057 Rostock, Germany Correspondence should be addressed to Alice Wichelhaus; alice.wichelhaus@med.uni-rostock.de Received 29 April 2016; Revised 8 June 2016; Accepted 9 June 2016 Academic Editor: Magali Cucchiarini Copyright © 2016 Alice Wichelhaus et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Tis study was designed to investigate the infuence of the amount of suture material on the formation of peritendinous adhesions of intrasynovial fexor tendon repairs. Materials and Methods. In 14 rabbits, the fexor tendons of the third and the fourth digit of the right hind leg were cut and repaired using a 2- or 4-strand core suture technique. Te repaired tendons were harvested afer three and eight weeks. Te range of motion of the afected toes was measured and the tendons were processed histologically. Te distance between the transected tendon ends, the changes in the peritendinous space, and cellular and extracellular infammatory reaction were quantifed by diferent staining. Results. A 4-strand core suture resulted in signifcantly less gap formation. Te 2- strand core suture showed a tendency to less adhesion formation. Doubling of the intratendinous suture material was accompanied by an initial increase in leukocyte infltration and showed a greater amount of formation of myofbroblasts. From the third to the eighth week afer fexor tendon repair, both the cellular and the extracellular infammation decreased signifcantly. Conclusion.A 4-strand core suture repair leads to a signifcantly better tendon healing process with less diastasis between the sutured tendon ends despite initially pronounced infammatory response. 1. Introduction Te aim of development in fexor tendon surgery is to achieve a strong suture tendon construct that allows for early active motion. Early mobilization is known to improve the outcome of fexor tendon repairs by reducing peritendinous adhesion formation and stimulating intrinsic tendon healing [1, 2]. By active motion pull-out, forces are applied to the tendon suture so that the risk of gap formation or even rerupture increases. Quite a number of studies can be found that deal with biomechanical testing of diferent suture techniques and suture materials, but only a few studies deal with the in vivo behavior of these suture techniques [2–5]. A multistrand core suture with multiple locking leads to a higher strength of the suture tendon construct but at the same time it increases the volume of the repaired tendon. Tis could possibly lead to tendon healing disorders through increased infammatory reaction in and around the tendon [6–10]. We therefore sought to investigate the efects of the num- ber of suture strands on tendon healing in the early and late stage in an animal model. Pivotal question was whether dif- ferences could be discovered in vivo between two- and four- strand core suture technique regarding gap formation, adhe- sion formation of the peritendinous space, and infammatory response on both the cellular and extracellular pathway. 2. Materials and Methods Te study was conducted on 14 adult female New Zealand white rabbits weighing 2600 to 4300 g. A test model for fexor tendon surgery is established for rabbits [11, 12]. Te animals were kept under standard animal laboratory conditions Hindawi Publishing Corporation BioMed Research International Volume 2016, Article ID 4063137, 6 pages http://dx.doi.org/10.1155/2016/4063137