The study was conducted with funds from the Sana Hospital Hof. Furthermore, authors want to thank Ms Hafenrichter (Serag Wiessner, Naila) for her untiring help with the experiments.

This article does not contain any studies with human participants or animals performed by any of the authors. The use of the human material was in full compliance with the university policy for use of cadavers and recognizable body parts, Institute of Anatomy, University of Erlangen.
1. Harvest the flexor tendons
<ol>
	<li>Harvesting the flexor digitorum profundus
	<ol>
		<li>Place a fresh cadaveric upper limb on the dissecting table with the ventral-palmar side facing the s...

<ol>
	<li>Hage, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=History+off-hand:+Bunnell's+no-man's+land.">History off-hand: Bunnell's no-man's land.</a> Hand. 14 (4), 570-574 (2019).</li><li>Verdan, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+repair+of+flexor+tendons.">Primary repair of flexor tendons.</a> Journal of Bone and Joint Surgery. 42 (4), 647-657 (1960).</li><li>Kessler, I., Nissim, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+repair+without+immobilization+of+flexor+tendon+division+within+the+digital+sheath.+An+experimental+and+clinical+study.">Primary repair without immobilization of flexor tendon division within the digital sheath. An experimental and clinical study.</a> Acta Orthopaedica Scandinavia. 40 (5), 587-601 (1969).</li><li>Waitayawinyu, T., Martineau, P. A., Luria, S., Hanel, D. P., Trumble, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+biomechanic+study+of+flexor+tendon+repair+using+FiberWire.">Comparative biomechanic study of flexor tendon repair using FiberWire.</a> The Journal of Hand Surgery. 33 (5), 701-708 (2008).</li><li>Polykandriotis, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexor+tendon+repair+with+a+polytetrafluoroethylene+(PTFE)+suture+material.">Flexor tendon repair with a polytetrafluoroethylene (PTFE) suture material.</a> Archives of Orthopaedic and Trauma Surgery. 139 (3), 429-434 (2019).</li><li>Polykandriotis, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polytetrafluoroethylene+(PTFE)+suture+vs+fiberwire+and+polypropylene+in+flexor+tendon+repair.">Polytetrafluoroethylene (PTFE) suture vs fiberwire and polypropylene in flexor tendon repair.</a> Archives of Orthopaedic and Trauma Surgery. 141 (9), 1609-1614 (2021).</li><li>Polykandriotis, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individualized+wound+closure-mechanical+properties+of+suture+materials.">Individualized wound closure-mechanical properties of suture materials.</a> Journal of Personalized Medicine. 12 (7), 1041 (2022).</li><li>Edsfeldt, S., Rempel, D., Kursa, K., Diao, E., Lattanza, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+flexor+tendon+forces+generated+during+different+rehabilitation+exercises.">In vivo flexor tendon forces generated during different rehabilitation exercises.</a> Journal of Hand Surgery. 40 (7), 705-710 (2015).</li><li>Amadio, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Friction+of+the+gliding+surface.+Implications+for+tendon+surgery+and+rehabilitation.">Friction of the gliding surface. Implications for tendon surgery and rehabilitation.</a> Journal of Hand Therapy. 18 (2), 112-119 (2005).</li><li>Wieskotter, B., Herbort, M., Langer, M., Raschke, M. J., Wahnert, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+different+peripheral+suture+techniques+on+the+biomechanical+stability+in+flexor+tendon+repair.">The impact of different peripheral suture techniques on the biomechanical stability in flexor tendon repair.</a> Archives of Orthopaedic and Trauma Surgery. 138 (1), 139-145 (2018).</li><li>Savage, R., Tang, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=History+and+nomenclature+of+multistrand+repairs+in+digital+flexor+tendons.">History and nomenclature of multistrand repairs in digital flexor tendons.</a> Journal of Hand Surgery. 41 (2), 291-293 (2016).</li><li>Lawrence, T. M., Davis, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+biomechanical+analysis+of+suture+materials+and+their+influence+on+a+four-strand+flexor+tendon+repair.">A biomechanical analysis of suture materials and their influence on a four-strand flexor tendon repair.</a> Journal of Hand Surgery. 30 (4), 836-841 (2005).</li><li>Lawrence, T. M., Davis, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Locking+loops+for+flexor+tendon+repair.">Locking loops for flexor tendon repair.</a> Annals of the Royal College of Surgeons of England. 87 (5), 385-386 (2005).</li><li>Kannas, S., Jeardeau, T. A., Bishop, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rehabilitation+following+zone+II+flexor+tendon+repairs.">Rehabilitation following zone II flexor tendon repairs.</a> Techniques in Hand and Upper Extremity Surgery. 19 (1), 2-10 (2015).</li><li>Tang, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+developments+are+improving+flexor+tendon+repair.">New developments are improving flexor tendon repair.</a> Plastic and Reconstructive Surgery. 141 (6), 1427-1437 (2018).</li><li>Dang, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+biomechanical+considerations+of+polytetrafluoroethylene+sutures.">Some biomechanical considerations of polytetrafluoroethylene sutures.</a> Archives of Surgery. 125 (5), 647-650 (1990).</li><li>Abellan, D., Nart, J., Pascual, A., Cohen, R. E., Sanz-Moliner, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+and+mechanical+evaluation+of+five+suture+materials+on+three+knot+configurations:+an+in+vitro+study.">Physical and mechanical evaluation of five suture materials on three knot configurations: an in vitro study.</a> Polymers. 8 (4), 147 (2016).</li><li>Silva, J. M., Zhao, C., An, K. N., Zobitz, M. E., Amadio, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gliding+resistance+and+strength+of+composite+sutures+in+human+flexor+digitorum+profundus+tendon+repair:+an+in+vitro+biomechanical+study.">Gliding resistance and strength of composite sutures in human flexor digitorum profundus tendon repair: an in vitro biomechanical study.</a> Journal of Hand Surgery. 34 (1), 87-92 (2009).</li><li>Chauhan, A., Palmer, B. A., Merrell, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexor+tendon+repairs:+techniques,+eponyms,+and+evidence.">Flexor tendon repairs: techniques, eponyms, and evidence.</a> Journal of Hand Surgery. 39 (9), 1846-1853 (2014).</li><li>Tolerton, S. K., Lawson, R. D., Tonkin, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+flexor+tendon+injuries+-+Part+2:+current+practice+in+Australia+and+guidelines+for+training+young+surgeons.">Management of flexor tendon injuries - Part 2: current practice in Australia and guidelines for training young surgeons.</a> Hand Surgery. 19 (2), 305-310 (2014).</li><li>Tang, J. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strong+digital+flexor+tendon+repair,+extension-flexion+test,+and+early+active+flexion:+experience+in+300+tendons.">Strong digital flexor tendon repair, extension-flexion test, and early active flexion: experience in 300 tendons.</a> Hand Clinics. 33 (3), 455-463 (2017).</li><li>Gray, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Grays Anatomy. , (2013).</li><li>McGregor, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fundamental Techniques of Plastic Surgery. 10th editon. , (2000).</li><li>Tsuge, K., Yoshikazu, I., Matsuishi, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repair+of+flexor+tendons+by+intratendinous+tendon+suture.">Repair of flexor tendons by intratendinous tendon suture.</a> Journal of Hand Surgery. 2 (6), 436-440 (1977).</li><li>Croog, A., Goldstein, R., Nasser, P., Lee, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+biomechanic+performances+of+locked+cruciate+four-strand+flexor+tendon+repairs+in+an+ex+vivo+porcine+model.">Comparative biomechanic performances of locked cruciate four-strand flexor tendon repairs in an ex vivo porcine model.</a> Journal of Hand Surgery. 32 (2), 225-232 (2007).</li><li>Tang, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Indications,+methods,+postoperative+motion+and+outcome+evaluation+of+primary+flexor+tendon+repairs+in+Zone+2.">Indications, methods, postoperative motion and outcome evaluation of primary flexor tendon repairs in Zone 2.</a> Journal of Hand Surgery. 32 (2), 118-129 (2007).</li><li>Head, W. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesion+barriers+in+cardiac+surgery:+A+systematic+review+of+efficacy.">Adhesion barriers in cardiac surgery: A systematic review of efficacy.</a> Journal of Cardiac Surgery. 37 (1), 176-185 (2022).</li><li>Pressman, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Teflon+or+Ivalon:+a+scoping+review+of+implants+used+in+microvascular+decompression+for+trigeminal+neuralgia.">Teflon or Ivalon: a scoping review of implants used in microvascular decompression for trigeminal neuralgia.</a> Neurosurgery Reviews. 43 (1), 79-86 (2020).</li><li>Pillukat, T., van Schoonhoven, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nahttechniken+und+Nahtmaterial+in+der+Beugesehnenchirurgie.">Nahttechniken und Nahtmaterial in der Beugesehnenchirurgie.</a> Trauma und Berufskrankheit. 18 (3), 264-269 (2016).</li><li>Dudenhoffer, D. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+biocompatibility+of+a+novel+expanded+polytetrafluoroethylene+suture+for+annuloplasty.">In vivo biocompatibility of a novel expanded polytetrafluoroethylene suture for annuloplasty.</a> The Thoracic and Cardiovascular Surgeon. 68 (7), 575-583 (2018).</li><li>Dy, C. J., Daluiski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Update+on+zone+II+flexor+tendon+injuries.">Update on zone II flexor tendon injuries.</a> Journal of the American Academy of Orthopaedic Surgeons. 22 (12), 791-799 (2014).</li><li>Killian, M. L., Cavinatto, L., Galatz, L. M., Thomopoulos, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+mechanobiology+in+tendon+healing.">The role of mechanobiology in tendon healing.</a> Journal of Shoulder and Elbow Surgery. 21 (2), 228-237 (2012).</li><li>Muller-Seubert, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrospective+analysis+of+free+temporoparietal+fascial+flap+for+defect+reconstruction+of+the+hand+and+the+distal+upper+extremity.">Retrospective analysis of free temporoparietal fascial flap for defect reconstruction of the hand and the distal upper extremity.</a> Archives of Orthopaedic and Trauma Surgery. 141 (1), 165-171 (2021).</li></ol>

In this line of experiments, a PTFE strand was evaluated as suturing material for flexor tendon repair. The protocol reproduces conditions that are like the in vivo situation in all but two aspects. First, the loads applied in vivo are repetitive, so a cyclically repeated type of loading might be better suitable. Second, over the first 6 weeks postoperatively, the significant shift from biomechanics toward biology as tendon healing progresses, which is a process that cannot be adequately addressed under...

The treatment of flexor tendon injuries of the hand has been an issue of controversy for over half a century. Until the 1960s, the anatomical area between the middle phalanx and the proximal palm was named "no man's land", to express that attempts of primary tendon reconstruction in this area were futile, producing very poor results1. However, in the 1960s, the issue of primary tendon repair was revisited by introducing new concepts for rehabilitation2. In the 1970s, with advances in neurosciences, new concepts of early rehabilitation could be developed, including dynamic splints3, but thereafter only marginal improvements could be achieved. Recently, new materials were introduced with significantly improved integral stability4,5 so that technical issues other than the failure of the suture materials came into focus, including cheese wiring and pullout6. 
Until recently, polypropylene (PPL) and polyester were widely used in flexor tendon repairs. A 4-0 USP (United States Pharmacopeia) strand of polypropylene corresponding to a diameter of 0.150-0.199 mm exhibits a linear tensile strength of less than 20 Newton (N)6,7, whereas flexor tendons of the hand can develop in vivo linear forces of up to 75 N8. After trauma and surgery, because of edema and adhesions, the resistance of the tissue advances more9. Classical techniques of tendon repair included two-strand configurations that had to be reinforced with additional epitendinous running sutures3,10. Newer polyblend polymer materials with substantially higher linear strength have brought about technical developments4; a single polyblend strand with a core of long chain ultra-high molecular weight polyethylene (UHMWPE) in combination with a braided jacket of polyester in the same diameter as PPL can withstand linear forces of up to 60 N. However, extrusion technologies can manufacture monofilamentous polymer strands exhibiting comparable mechanical properties6. 
Repair techniques have also evolved in the last decade. Two-strand tendon repair techniques have given way to more elaborate four- or six-strand configurations11,12. By the use of a looped suture13, the number of knots can be diminished. By combining newer materials with newer techniques, an initial linear strength of over 100 N can be achieved4. 
An individualized rehabilitation regimen should be advocated in any case, taking into account special patient attributes and tendon repair techniques. For instance, children and adults unable to follow complex instructions for a long time should be subjected to delayed mobilization. Less strong repairs should be mobilized by passive motion alone14,15. Otherwise, early active motion regimens should be the golden standard. 
The overall goal of this method is to evaluate a novel suture material for flexor tendon repair. To commend on the rationale of the protocol, this technique is an evolution of formerly validated protocols found in the literature4,10,12,16 as a means of assessment of suture materials under conditions that resemble clinical routine. Using a modern servohydraulic materials testing system, a traction velocity of 300 mm/min can be set resembling in vivo stress, in contrast to earlier protocols using 25-180 mm/min4,10, accounting for limitations in software and measurement equipment. This method is suitable for ex vivo studies on flexor tendon repairs, and in a wider sense for evaluation of the application of suture materials. In materials sciences, such experiments are routinely used to evaluate polymers and other classes of materials17. 
Phases of the study: The studies were performed in two phases; each was divided into two or three subsequent steps. In the first phase, a polypropylene (PPL) strand and a polytetrafluoroethylene (PTFE) strand were compared. Both 3-0 USP and 5-0 USP strands were utilized to mimic the real clinical conditions. The mechanical properties of the materials themselves were first investigated, although being medical devices, these materials have been extensively tested already. For these measurements, N = 20 strands were measured for linear tensile strength. Knotted strands were also investigated since knotting alters linear tension strength and produces a potential breaking point. The main part of the first phase was about testing the performance of the two different materials under clinical conditions. In addition, 3-0 core repairs (two-strand Kirchmayr-Kessler with the modifications of Zechner and Pennington) were performed and tested for linear strength. For an additional wing of the investigation, an epitendinous 5-0 running suture was added to the repair for additional strength18,19. 
In a subsequent phase, a comparison between three suturing materials was performed, including PPL, UHMWPE and PTFE. For all comparisons, a USP 4-0 strand was used, corresponding to a diameter of 0.18 mm. For a complete list of the materials used, refer to the Table of Materials. For the final step, an Adelaide20 or a M-Tang21 core repair was performed as described earlier.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Chirobloc</td>
			<td>AMT AROMANDO Medizintechnik GmbH</td>
			<td>CBM</td>
			<td>Hand Fixation</td>
		</tr>
		<tr>
			<td>Cutfix Disposable scalpel</td>
			<td>B. Braun Medical Inc, Germany</td>
			<td>5518040</td>
			<td>Safety one use blade</td>
		</tr>
		<tr>
			<td>Coarse paper/ Aluminium Oxide Rhynalox</td>
			<td>Indasa</td>
			<td>440008</td>
			<td>abrasive with a grit size of ISO P60&#160;</td>
		</tr>
		<tr>
			<td>Fiberloop 4-0</td>
			<td>Arthrex GmbH</td>
			<td>AR-7229-20</td>
			<td>Ultra-high molecular weight polyethylene with a braided jacket of polyester 4-0</td>
		</tr>
		<tr>
			<td>G20 cannula Sterican</td>
			<td>B Braun</td>
			<td>4657519</td>
			<td>100 Pcs package</td>
		</tr>
		<tr>
			<td>Isotonic Saline 0.9% Bottlepack 500 mL&#160;</td>
			<td>Serag Wiessner GmbH</td>
			<td>002476</td>
			<td>Saline 500 mL</td>
		</tr>
		<tr>
			<td>KAP-S Force Transducer</td>
			<td>A.S.T. &#8211; Angewandte System Technik GmbH</td>
			<td>AK8002</td>
			<td>Load cell</td>
		</tr>
		<tr>
			<td>Metzenbaum Scissors (one way, 14 cm)</td>
			<td>Hartmann</td>
			<td>9910846</td>
			<td></td>
		</tr>
		<tr>
			<td>Screw grips, Type 8133, Fmax 1 kN</td>
			<td>ZwickRoell GmbH &#38; Co. KG,</td>
			<td>316264</td>
			<td></td>
		</tr>
		<tr>
			<td>Seralene 3-0</td>
			<td>Serag Wiessner GmbH</td>
			<td>LO203413</td>
			<td>Polypropylene Strand 3-0</td>
		</tr>
		<tr>
			<td>Seralene 4-0</td>
			<td>Serag Wiessner GmbH</td>
			<td>LO151713</td>
			<td>Polypropylene Strand 4--0</td>
		</tr>
		<tr>
			<td>Seralene 5-0</td>
			<td>Serag&#160; Wiessner GmbH</td>
			<td>LO103413</td>
			<td>Polypropylene Strand 5-0</td>
		</tr>
		<tr>
			<td>Seramon 3-0</td>
			<td>Serag Wiessner GmbH</td>
			<td>MEO201714</td>
			<td>Polytetrafluoroethylene 3-0</td>
		</tr>
		<tr>
			<td>Seramon 4-0</td>
			<td>Serag Wiessner GmbH</td>
			<td>MEO151714</td>
			<td>Polytetrafluoroethylene 4-0</td>
		</tr>
		<tr>
			<td>Seramon 5-0</td>
			<td>Serag Wiessner GmbH</td>
			<td>MEO103414</td>
			<td>Polytetrafluoroethylene 5-0</td>
		</tr>
		<tr>
			<td>testXpert III testing software (Components following)</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>See following points for components</td>
			<td>testing software</td>
		</tr>
		<tr>
			<td>Results Editor</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035615</td>
			<td></td>
		</tr>
		<tr>
			<td>Layout Editor</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035617</td>
			<td></td>
		</tr>
		<tr>
			<td>Report Editor</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035620</td>
			<td></td>
		</tr>
		<tr>
			<td>Export Editor</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035618</td>
			<td></td>
		</tr>
		<tr>
			<td>Organization Editor</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035614</td>
			<td></td>
		</tr>
		<tr>
			<td>Virtual testing machine VTM</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035522</td>
			<td></td>
		</tr>
		<tr>
			<td>Language swapping</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035622</td>
			<td></td>
		</tr>
		<tr>
			<td>Upload/download</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035957</td>
			<td></td>
		</tr>
		<tr>
			<td>Traceability</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035624</td>
			<td></td>
		</tr>
		<tr>
			<td>Extended control mode</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035959</td>
			<td></td>
		</tr>
		<tr>
			<td>Video Capturing</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035575</td>
			<td></td>
		</tr>
		<tr>
			<td>Plus testControl II</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1033655</td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature control</td>
			<td>ZwickRoell GmbH &#38; Co. KG, Ulm, Germany</td>
			<td>1035623</td>
			<td></td>
		</tr>
		<tr>
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polytetrafluoroethylene (ptfe) as a suture material in tendon surgery

With the evolution of suture materials, there has been a change in paradigms in primary and secondary tendon repair. Improved mechanical properties allow more aggressive rehabilitation and earlier recovery. However, for the repair to hold against higher mechanical demands, more advanced suturing and knotting techniques must be assessed in combination with those materials. In this protocol, the use of polytetrafluoroethylene (PTFE) as a suture material in combination with different repair techniques was investigated. In the first part of the protocol, both linear tension strength and elongation of knotted against not-knotted strands of three different materials used in flexor tendon repair were evaluated. The three different materials are polypropylene (PPL), ultra-high molecular weight polyethylene with a braided jacket of polyester (UHMWPE), and polytetrafluoroethylene (PTFE). In the next part (ex vivo experiments with cadaveric flexor tendons), the behavior of PTFE using different suture techniques was assessed and compared with PPL and UHMWPE.
This experiment is comprised of four steps: harvesting of the flexor tendons from fresh cadaveric hands, transection of the tendons in a standardized manner, tendon repair by four different techniques, mounting, and measurement of the tendon repairs on a standard linear dynamometer. The UHMWPE and PTFE showed comparable mechanical properties and were significantly superior to PPL in terms of linear traction strength. Repairs with four- and six-strand techniques proved stronger than two-strand techniques. Handling and knotting of PTFE are a challenge due to very low surface friction but fastening of the four- or six-strand repair is comparatively easy to achieve. Surgeons routinely use PTFE suture material in cardiovascular surgery and breast surgery. The PTFE strands are suitable for use in tendon surgery, providing a robust tendon repair so that early active motion regimens for rehabilitation can be applied.

Tendon repairs: When a two-strand Kirchmayr-Kessler technique was used alone, there was a high rate of slippage with repairs reaching a linear strength of approximately 30 N (Figure 2 and Figure 5A)5. In vivo, the tendon of the flexor digitorum profundus can develop linear traction of up to 75 N8. Under post-traumatic conditions, this value can be even higher due to friction, swelling, and...

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Polytetrafluoroethylene PTFE as a Suture Material in Tendon Surgery

The present protocol illustrates a method for assessing the biophysical properties of tendon repairs ex vivo. A polytetrafluoroethylene (PTFE) suture material was evaluated by this method and compared to other materials under different conditions.

Polytetrafluoroethylene (PTFE) as a Suture Material in Tendon Surgery

With the evolution of suture materials, there has been a change in paradigms in primary and secondary tendon repair. Improved mechanical properties allow ...

With this protocol, we were able to assess the mechanical properties of a flexor tendon repair. Novel developments, such as linear tension strength, can be reliably evaluated this way. Even slight differences can be detected.To begin, place a fresh cadaveric upper limb on the dissecting table, with the ventral palmar side facing the surgeon. Using a number 15 scalpel, place a median longitudinal incision at the index finger on the palmar side, beginning from the distal phalanx, distally toward the A1 pulley over the metacarpophalangeal joint. Sever the A1 and A2 pulleys longitudinally without injuring the flexor tendons, and then sever the flexor digitorum profundus at the level of the distal interphalangeal joint using a scalpel.Use a tendon retractor to set the tendon under traction and retrieve the flexor digitorum profundus at the level of the A1 pulley. Then, make a six centimeter transversal incision on the rasceta crease, using a number 15 scalpel. Make another transversal incision 10 centimeters proximal to the rasceta.Next, make a longitudinal incision at the median of the palmar side of the forearm, connecting the two transversal incisions. Develop two opposing skin flaps at the level of the forearm fascia to expose the flexor tendons. The flexor tendons are readily identifiable under the skin.Again, use a tendon retractor to place the flexor digitorum tendon under traction, and retract the tendon proximal to the wrist. Sever the tendon at the musculotendinous junction for maximal tendon length with a number 11 scalpel, and place the tendon specimen into 500 milliliters of 0.9%saline solution. Repeat these steps for the third to fifth fingers.Fix the tendon specimen on an expanded polystyrene plate with pins or 18-gauge cannulas, and transect the tendon in the middle, using a scalpel with a number 11 blade. Next, for the Adelaide"cross lock 4-strand core repair, insert the needle into the left stump of the transected tendon, and follow the path of the tendon on the surgeon's side for 1.5 centimeters, and exit at the surface of the tendon. Insert the needle three millimeters to the left and take a bite of three millimeters, exiting toward the surgeon.Then, insert the needle three millimeters to the right, next to the exit point of the first path, and follow the tendon to the very side until the left stump. Insert the needle into the right stump in a path at the very outer part of the tendon, and exit approximately 1.5 centimeters to the right of the stump. Then, insert the needle again at three millimeters to the right.Take a grasp, and exit at the side of the tendon. Insert the needle back toward the right stump, entering approximately three millimeters to the left. Exit at the right stump, and enter again into the left stump for 1.5 centimeters.Grasp a portion of the tendon of three millimeters with the suture, and exit near the midline. Reinsert the needle three millimeters nearer to the stump, and follow the direction of the tendon to the right, making sure to exit at the stump. Insert the needle into the right stump, and follow the tendon fibers approximately 1.5 centimeters to the right.Exit at the surface. Re-enter the tendon further to the right and take a grasp, aiming to the far side. Insert the needle three millimeters to the left, and follow the tendon, exiting at the stump.Now, tie a surgical knot with eight throws, alternating the direction manually. For M-Tang 6-strand core repair, insert the needle of the loop approximately 1.5 centimeters from the right stump of the tendon, and grasp a portion of the tendon of approximately three millimeters in size. Then, pass the needle through the loop and insert the needle into the surface of the tendon.Follow the path of the tendon and exit between the stumps. Re-insert the needle into the opposite stump and follow the tendon in the deep plane for 1.8 centimeters. Exit at the surface of the tendon.Next, enter three millimeters near the stump. Follow a transversal path to the far side of the tendon and exit there. Insert the needle bearing the loop three millimeters to the left, further away from the stumps.Follow the path of the tendon and exit between the stumps. Re-enter at the opposite stump and exit 1.5 centimeters to the right at the surface of the tendon. Cut one of the two strands arming the needle with scissors.Then, insert the needle and grasp a three millimeter portion of the tendon. Manually tie a surgical knot with eight throws, alternating the direction. Take another loop suture and perform a Tsuge suture by grasping a portion of the tendon of approximately three millimeters at 1.5 centimeters to the right.Re-insert the needle and follow the path of the tendon to the left. Exit between the stumps. Re-enter into the left stump and follow the path of the tendon for 1.5 centimeters.Exit at the surface of the tendon. Cut one of the two strands arming the needle with a pair of scissors, and re-insert the needle, grasping three millimeters of the tendon. Finally, tie a surgical knot manually with eight throws, alternating the direction.The linear tensile strength of polypropylene and polytetrafluoroethylene, when using the Kirchmayr-Kessler technique, is shown here. There was no difference between the two materials in terms of linear tensile strength, although polytetrafluoroethylene was somewhat weaker due to slippage. When an epitendinous running suture was used, slippage was less of a problem for the polypropylene repairs, but the repair broke down at approximately 50 Newton.On the contrary, repairs with polytetrafluoroethylene failed at around 70 Newton due to slippage. With the combination of a stronger repair, such as 4-strand Adelaide"or 6-strand M-Tang, and a stronger suture material, such as polytetrafluoroethylene or multistrand, a linear tension strength of 75 Newton or more could be achieved. No significant advantage of the 4-strand versus the 6-strand technique was observed.A summary of the results from the flexor tendon repairs is shown here. Repairs with polytetrafluoroethylene displayed a peak tensile strength comparable to multistrand. Both the repairs were significantly stronger than those with polypropylene.The repairs should be performed symmetrically at both stumps of the severed tendon. The multistrand suture should be rinsed in order for the suture to slip evenly through the fibers of the tendon. The knots of the repair poses some problems.Maybe in the future, some knotless kind of repair can be developed.

polytetrafluoroethylene-ptfe-as-a-suture-material-in-tendon-surgery

Research

JoVE Journal

Medicine

2.8K ビュー.  University of Erlangen Medical Center. このプロトコルにより、屈筋腱修復の機械的特性を評価することができました。この方法で、線形張力強度などの新しい開発を確実に評価できます。わずかな違いでも検出できます。まず、腹側の手のひら側を外科医に向けて、解剖台に新しい死体の上肢を置きます。15番のメスを使用して、手のひら側の人差し指に、遠位指節から始まり、中手指節関節の上のA1滑...