Tendons primarily transmit muscle-derived force to bone while acting together with ligamentous structures to provide dynamic joint stability, thereby preventing joint translation.1 Although tendon injuries in dogs are rare, accounting for < 1% of all appendicular musculoskeletal diagnoses,2 type 3 strain injuries are debilitating and seldom resolve without surgical intervention.3 Current standard of care for veterinary patients with complete transection of a tendon is surgical intervention with extensive postoperative rehabilitation.3
Two important factors critical to tendinous healing at the site of tenorrhaphy are maintenance of blood supply and prevention of gap formation between the ends of the transected tendon.4 Therefore, the main goal of tenorrhaphy is to maintain tendinous apposition such that gap formation is minimized and direct contact healing can occur without the development of a fibrous scar.5–7 Risk of rerupture of a tendon is increased in the first 6 weeks after tenorrhaphy with the formation of a gap > 3 mm, and the development of fibrous tissue, which is mechanically inferior to the normal connective tissue, results in decreased strength at the repair site.4,8
Tenorrhaphy is commonly performed to achieve reapposition of the ends of a transected tendon and subsequent realignment of collagen fibrils.9–13 Early treatment and use of the strongest repair possible are vital to restore musculotendinous function in dogs with tendinous transection. Tenorrhaphy includes use of a core suture technique, such as 3-loop pulley, LL, and Krakow,8,14–22 and, in people, often includes concurrent placement of epitendinous sutures,23 which have been only recently described24–26 in dogs. The LL technique is most commonly used in dogs because of its ease and attainment of uniform apposition of the transected ends of the tendon.19 Load transmission to the core suture of the tenorrhaphy is considered to be the initiator of repair failure.23 Because core suture repairs have been shown to be the strongest component of tenorrhaphy,23 more attention should be focused on understanding and improving this component of the tenorrhaphy.
The caliber of suture used with a core technique for repair of the flexor tendons of the human hand has been positively correlated with tensile strength, specifically the resistance to deformation when a load is applied and the load applied prior to failure.20–22,27
However, to our knowledge, the effect of suture caliber on the tensile strength of tenorrhaphy has not been previously evaluated in dogs. In the authors' experience, suture caliber is often selected on the basis of patient size and surgeon's preference. Yet, these criteria may not be appropriate for selecting the suture caliber for tenorrhaphies; therefore, understanding the effect of suture caliber on the tensile strength of tenorrhaphies may aid with suture selection and lead to improved patient outcomes.
The objective of the study reported here was to evaluate the effect of suture caliber on the tensile strength of tenorrhaphies performed with a LL technique in cadaveric canine tendons. We hypothesized that large-caliber suture would have greater tensile strength, compared with small-caliber suture.
Materials and Methods
Specimen collection
Cadavers of 30 medium- to large-breed skeletally mature adult dogs were obtained from an animal shelter immediately after the dogs had been euthanized for reasons unrelated to this study. Dogs weighed between 28 and 32 kg and had no evidence of soft tissue or musculoskeletal disease; however, sex and health status prior to euthanasia were not recorded. If gross abnormalities of the bone, tendon, or musculotendinous unit of interest were appreciated, the tendons of these dogs were excluded. An animal care and use committee protocol was not required by the Department of Clinical Sciences, College of Veterinary Medicine at North Carolina State University for the purposes of this study.
Paired forelimbs were harvested from each cadaver. The methods used for harvesting and preserving the SDFTs were previously reported.24–26 Briefly, the SDFT was manually dissected from each forelimb. The musculotendinous unit, origin of the SDFT on the medial aspect of the humeral condyle, and insertion of the SDFT on the manus were carefully isolated to ensure the removal of all palmar retinacular attachments. All other antebrachial tissues were removed and discarded. A band sawa was used to transversely transect the metacarpal bones 10 mm distal to the carpometacarpal joint. Tissue distal to this point on the manus was left intact. Likewise, the humerus at the level of the distal metaphysis was transected 40 mm proximal to the supratrochlear foramen. The resulting specimen consisted of the distal portion of the humerus, musculotendinous unit, and tendinous insertion on the remaining phalanges. Specimens were kept moist with saline (0.9% NaCl) solution during harvesting. Then, specimens were wrapped in gauze soaked with saline solution and stored at −20°C, as described.28
Treatment groups
Tendons were randomly assigned via an electronic number generatorb to 5 treatment groups of 12 tendons/group. Tenorrhaphy was performed with 1 manufacturer'sc polypropylene suture of 1 of 5 calibers (treatments): size-0, 2-0, 3-0, 4-0, and 5-0. Suture was for single use, and after a sterile package of suture was opened, the suture was used immediately. Packages of suture were used within the manufacturer's date of expiration.
Tenotomy and tenorrhaphy
The methods used for tenotomy and tenorrhaphy have been previously reported.26 Briefly, specimens were thawed for 10 to 12 hours at room temperature (21°C), and a standardized tenotomy was performed with a No. 10 scalpel blade in a transverse plane. A hard, durable surface facilitated the tenotomy by providing counterpressure on the tendon. A calibrated ruler was used to ensure the tenotomy was performed 25 mm distal to the level of the musculotendinous junction. The distal cut surface of the tendon, next to a calibrated ruler, was then photographedd; the photograph was obtained parallel to and at a distance of 100 mm from the cut surface of the tendon. A single investigator (Y-JC) measured the cross-sectional area of each tendon by using an imaging software program.e
Tenorrhaphy via an LL technique as described elsewhere15 was performed by a board-certified small animal surgeon (DJD) who had experience with this procedure in research and clinical settings. Sutures were tightened to achieve close apposition without bunching of the tendon ends at the repair site. Then, the suture was secured with a square knot plus 3 additional throws and was cut 3 mm from the knot. To prevent tissue desiccation, specimens were kept moist during tenorrhaphy by use of saline solution applied with a spray bottle.
Mechanical testing
Testing was completed in 3 sessions with a uniaxial materials testing machinef as previously described26 (Figure 1). Briefly, a bone clampg affixed to a mechanical vise was used to secure the manus. The segment of humeral bone was secured to a customized jig with a 3.5-mm-diameter stainless steel bolt placed transversely through the supracondylar foramen. A high-speed digital camerah aligned with the tenorrhaphy site and placed at a distance of 20 cm from the construct was used to film each test at 50 frames/s.
Photograph of the uniaxial materials testing machine with a canine SDFT specimen loaded in the customized jig (A). Notice the tenorrhaphy site (square). A magnified view of the tenorrhaphy site and construct of an LL pattern with 2-0 polypropylene suture is provided (inset; B). The scale on the right side is in centimeters.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Photograph of the uniaxial materials testing machine with a canine SDFT specimen loaded in the customized jig (A). Notice the tenorrhaphy site (square). A magnified view of the tenorrhaphy site and construct of an LL pattern with 2-0 polypropylene suture is provided (inset; B). The scale on the right side is in centimeters.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Photograph of the uniaxial materials testing machine with a canine SDFT specimen loaded in the customized jig (A). Notice the tenorrhaphy site (square). A magnified view of the tenorrhaphy site and construct of an LL pattern with 2-0 polypropylene suture is provided (inset; B). The scale on the right side is in centimeters.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
A consistent resting tendon length was obtained by applying a preload of 2 N. After calibration, a distraction rate of 20 mm/min was applied to the construct. Distraction continued until the construct catastrophically failed because of suture pullout through the tendon substance or suture breakage; the load at which failure occurred was defined as failure force. The point at which nonlinear deformation of the construct was noted was defined as yield force, and the maximum force measured during each test was defined as peak force. The test system softwarei collected load and displacement data at a frequency of 100 Hz. Time, load, and displacement data were entered into a spreadsheet software program.j Yield, peak, and failure forces were identified visually by examination of a plot of load and displacement data. A single investigator (Y-JC) visually determined the cause of catastrophic failure in real time and again later by review of recorded video with the aid of an imaging software program.e A single investigator (DJD) reviewed all collated data.
Statistical analysis
On the basis of failure forces noted in a previous study29 and the results of our preliminary work, sample size calculation determined that 12 tendons/treatment group would allow for ≥ 90% probability (with 95% confidence) to detect a mean ± SD difference of 20 ± 5 N among treatment groups. Data were assessed for parametric distribution by use of the Shapiro-Wilk test. Continuous variables were normally distributed and reported as mean ± SD. Mean differences in failure force among treatment groups were assessed via a mixed linear model. Pairwise comparisons of least squares mean were conducted with Bonferroni adjustment for multiple comparisons. Proportional distributions for cause of failure were compared among treatment groups with the Fisher exact test. All analyses were performed with commercially available software.k Values of P < 0.05 were considered significant.
Results
No specimens were rejected at the time of specimen harvest or mechanical testing; therefore, results for all SDFTs were included in the statistical analysis. Treatment groups included an approximately equal distribution of left and right forelimbs (P = 0.856). Mean ± SD cross-sectional area of tendons was 0.22 ± 0.04 cm2 and was not significantly (P = 0.758) different among treatment groups and between contralateral limbs.
Compared with small-caliber suture (3-0, 4-0, and 5-0), large-caliber suture (size-0 and 2-0) had significantly (P < 0.001) greater mean yield force (Table 1; Figure 2). However, mean yield force did not significantly (P = 0.051) differ between large-caliber suture (size-0 vs 2-0) and did not significantly (P > 0.283) differ among small-caliber suture (3-0 vs 4-0, 3-0 vs 5-0, and 4-0 vs 5-0).
Mean ± SD values for parameters of tensile strength of 60 canine SDFT constructs (12 constructs/treatment group) in which the SDFTs were transected and tenorrhaphies performed with different sizes of polypropylene suture in an LL technique.
| Treatment group | Yield force (N) | Peak force (N) | Failure force (N) |
|---|---|---|---|
| Size-0 | 59.8 ± 17.8a | 75.4 ± 2.6a | 73.5 ± 3.1a |
| 2-0 | 46.0 ± 13.3a | 53.8 ± 8.4b | 54.4 ± 7.1b |
| 3-0 | 19.1 ± 8.5b | 28.9 ± 4.8c | 28.7 ± 4.9c |
| 4-0 | 12.6 ± 7.7b | 18.9 ± 3.3d | 18.7 ± 3.4d |
| 5-0 | 8.3 ± 3.2b | 8.8 ± 2.8e | 8.8 ± 2.8e |
Values within each column with different superscript letters are significantly (P < 0.05) different.
Box-and-whisker plots for yield force of 60 canine SDFT constructs in which the SDFTs had been transected and tenorrhaphies performed with size-0, 2-0, 3-0, 4-0, and 5-0 polypropylene suture (12 SDFTs/suture caliber) in an LL technique. Large-caliber suture (size-0 and 2-0) had significantly (P < 0.001) greater yield force, compared with small-caliber suture (3-0, 4-0, and 5-0). However, the differences between size-0 and 2-0 suture and among 3-0, 4-0, and 5-0 sutures were not significant (P = 0.051 and P > 0.283, respectively). The horizontal line within each box represents the median, boxes represent interquartile (25th to 75th percentile) range, and whiskers indicate the maximum and minimum values.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Box-and-whisker plots for yield force of 60 canine SDFT constructs in which the SDFTs had been transected and tenorrhaphies performed with size-0, 2-0, 3-0, 4-0, and 5-0 polypropylene suture (12 SDFTs/suture caliber) in an LL technique. Large-caliber suture (size-0 and 2-0) had significantly (P < 0.001) greater yield force, compared with small-caliber suture (3-0, 4-0, and 5-0). However, the differences between size-0 and 2-0 suture and among 3-0, 4-0, and 5-0 sutures were not significant (P = 0.051 and P > 0.283, respectively). The horizontal line within each box represents the median, boxes represent interquartile (25th to 75th percentile) range, and whiskers indicate the maximum and minimum values.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Box-and-whisker plots for yield force of 60 canine SDFT constructs in which the SDFTs had been transected and tenorrhaphies performed with size-0, 2-0, 3-0, 4-0, and 5-0 polypropylene suture (12 SDFTs/suture caliber) in an LL technique. Large-caliber suture (size-0 and 2-0) had significantly (P < 0.001) greater yield force, compared with small-caliber suture (3-0, 4-0, and 5-0). However, the differences between size-0 and 2-0 suture and among 3-0, 4-0, and 5-0 sutures were not significant (P = 0.051 and P > 0.283, respectively). The horizontal line within each box represents the median, boxes represent interquartile (25th to 75th percentile) range, and whiskers indicate the maximum and minimum values.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Mean peak force (P < 0.001) differed among treatment groups, with significantly (P < 0.001) more load required to reach peak force as the suture caliber increased. Likewise, mean failure force was (P < 0.001) different among all treatment groups, with significantly (P < 0.001) more load required for failure of large-caliber suture, compared with that for small-caliber suture (Figure 3).
Box-and-whisker plots of failure force of the SDFT constructs in Figure 2. Mean failure force was significantly (P < 0.001) different among all suture calibers, with significantly (P < 0.001) more load required for failure for large-caliber suture (size-0 and 2-0), compared with that for small-caliber suture (3-0, 4-0, and 5-0). See Figure 2 for key.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Box-and-whisker plots of failure force of the SDFT constructs in Figure 2. Mean failure force was significantly (P < 0.001) different among all suture calibers, with significantly (P < 0.001) more load required for failure for large-caliber suture (size-0 and 2-0), compared with that for small-caliber suture (3-0, 4-0, and 5-0). See Figure 2 for key.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Box-and-whisker plots of failure force of the SDFT constructs in Figure 2. Mean failure force was significantly (P < 0.001) different among all suture calibers, with significantly (P < 0.001) more load required for failure for large-caliber suture (size-0 and 2-0), compared with that for small-caliber suture (3-0, 4-0, and 5-0). See Figure 2 for key.
Citation: American Journal of Veterinary Research 81, 9; 10.2460/ajvr.81.9.714
Causes of catastrophic failure (P < 0.001) differed between tenorrhaphies in which size-0 suture was used and tenorrhaphies in which small-caliber suture was used. Suture breakage was observed for all 36 constructs in which 3-0, 4-0, and 5-0 suture was used. Breakage of 2-0 suture was observed for 10 of 12 constructs. In contrast, all 12 constructs with size-0 suture failed because of suture pullout through the tendon substance.
Discussion
This purpose of the present study was to determine the effect of caliber size of polypropylene suture used for tenorrhaphy with an LL technique on the tensile strength of canine tendon constructs. We observed that tensile strength was the greatest for size-0 suture, with catastrophic failure because of suture pullout through the tendon substance being noted for all 12 constructs with size-0 suture.
Taras et al,21 Barrie et al,22 and Hatanaka and Manske30 studied the effect of suture caliber on tensile strength of core tenorrhaphies in people and concluded that tensile strength is directly related to suture caliber in flexor tendon models of the hand. Results of the present study were consistent with their findings. Additionally, Taras et al21 proposed that tenorrhaphies could be strengthened by increasing suture caliber without having to increase the complexity of the core repair technique.
Yield force, the maximum load that a construct can withstand before deformation in a plastic fashion becomes permanent (ie, before attaining this load, the construct will act elastically and return to its normal length if the load is discontinued, but after attaining this load, the construct will not return to its normal length), for size-0 and 2-0 caliber suture was approximately 2.5 to 3 times that for 3-0 suture. Our study also showed that peak and failure forces incrementally increased as the suture caliber was increased, with forces for size-0 approximately 2.6 times and for size 2-0 approximately 1.4 times those for 3-0. However, suture of calibers > 2-0 are generally not used for the repair of zone 2 flexor tendons in people because as suture caliber increases, knot size increases and large extratendinous knots will increase resistance to tendon gliding.20,22 Maintaining glide function is important to retaining normal flexion. Protruding knots of large-caliber suture may irritate surrounding soft tissue and lead to the development of fibrous tissue, which will limit flexion. However, because glide function in dogs is thought to not be as clinically important as the overall strength of the tenorrhaphy, we included size-0 and 2-0 suture in our study. Strength of the tenorrhaphy is prioritized in veterinary patients because, unlike human patients, veterinary patients are unlikely to subject themselves to controlled incremental weight-bearing during rehabilitation after surgery.
Suture of size-0 failed exclusively because of suture pullout through the tendon substance, compared with small-caliber suture that failed because of suture breakage. Uslu et al31 reported a similar phenomenon in an ovine tendon study in which the likelihood of suture pullout was greater with the use of large-caliber suture. When small-caliber suture is used, the suture becomes the weakest component of the tenorrhaphy. In contrast, when large-caliber suture is used, the weakest component of the tenorrhaphy is the interaction between the suture and the linear alignment of collagen fibers that form the tendon core. Therefore, in our study, less force was required to cause failure with small-caliber suture, resulting in suture breakage, and greater force was required to cause failure with large-caliber suture, resulting in suture pullout through the tendon substance rather than suture breakage. Use of different suture types and patterns may yield disparate results; therefore, our results should be interpreted with caution.
When large-caliber suture is used, the tenorrhaphy may be able to withstand earlier loading and protected active-motion rehabilitative exercises while simultaneously avoiding failure. Surgeons may also be able to reduce reliance on active stabilization methods, such as external coaptation and external skeletal fixator placement, when using large-caliber suture; active stabilization has been associated with frequent postoperative morbidities, such as skin sores and infection.32 We also believe that tenorrhaphy failure rates will decrease with the use of 2-0 suture or larger for core tendinoplasty in conjunction with circumferential epitendinous sutures. Epitendinous sutures are commonly placed to reinforce core zone 2 flexor repairs in people after tendon rupture or laceration.9 Dy et al,33 in a meta-analysis of studies involving repairs of flexor tendons of the human hand, found that the addition (vs no addition) of epitendinous sutures decreased reoperation rates attributable to the failure of the core repair by 84%. By optimizing the strength of the core repair in dogs, we believe that the rate of postoperative failures can also be decreased. In a canine ex vivo model, the addition of epitendinous sutures to a core LL technique resulted in a 177% increase in yield force and a 151% increase in tensile strength, compared with the use of a core LL technique alone.24 Also, in another recent study,26 the concurrent placement of epitendinous sutures of size-0 with a core LL technique for the same tendon construct used in the present study increased the tensile strength of tenorrhaphies.
Our study had limitations inherent to its ex vivo design, including the inability to assess tendinous inflammation, fibrosis, and blood supply. A major limitation was that we did not report the gap formation between the ends of the tendon; however, this omission was deliberate. We acknowledge that preventing gap formation is an important component of tendinous repair.4–7 Yet, when small-caliber suture (4-0 and 5-0) was used for tenorrhaphy, suture breakage occurred prior to the development of a readily identified gap. Therefore, small-caliber suture would have seemed superior to large-caliber suture on the basis of the lack of gap formation. Also, failure force was determined through application of a single load, similar to previous studies,14–16,18,26,34 rather than through cyclical loading, which more accurately represents in vivo conditions.35 Lastly, we used the SDFTs from a homogeneous group of large-breed adult dogs; therefore, our results may not apply to smaller, thinner SDFTs from smaller dogs or to other tendons, such as the common calcaneal tendon that is composed of contributions from multiple musculotendinous units.
In conclusion, use of large-caliber suture with a core LL technique for tenorrhaphy of transected SDFTs in an ex vivo canine tendon construct resulted in significantly greater tensile strength, compared with the use of small-caliber suture. Large-caliber suture may be best for routine tendinoplasty in dogs, but in vivo studies are required prior to clinical implementation to determine the effect of large-caliber suture on tendinous healing, glide function, and clinical outcome.
Acknowledgments
No external funding was used in this study. Suture material was provided by Medtronic Inc, Mansfield, Mass. The authors declare that there were no conflicts of interest.
ABBREVIATIONS
| LL | Locking-loop |
| SDFT | Superficial digital flexor tendon |
Footnotes
Delta Power Equipment Corp, Anderson, SC.
Random number generator, Research Randomizer, Lancaster, Pa.
Surgipro, Covidien Ltd, Dublin, Ireland.
iPhone 8, Apple Inc, Cupertino, Calif.
ImageJ, National Institute of Health, Bethesda, Md.
Instron Model 5967, Instron Inc, Norwood, Mass.
SKU 1652-1, Sawbones, Vashon Island, Wash.
Panasonic Lumix DMC-FZ200, Panasonic Corp, Newark, NJ.
Bluehill 3, Instron Inc, Norwood, Mass.
Microsoft Excel, Microsoft Corp, Redmond, Wash.
SAS, version 9.4, SAS Institute Inc, Cary, NC.
References
1. Frank CB. Form and function of tendon and ligament. In: O'Keefe RJ, Jacobs JJ, Chu CR, et al, eds. Orthopaedic basic science: foundations of clinical practice. 4th ed. Rosemont, Ill: Lippincott Williams & Wilkins, 2018;191–223.
2. Johnson J, Austin C, Breur G. Incidence of canine appendicular musculoskeletal disorders in 16 veterinary teaching hospitals from 1980 through 1989. Vet Comp Orthop Traumatol 1994;7:56–69.
3. Johnston SA, Tobias KM. Muscle and tendon disorders. In: Veterinary surgery: small animal expert consult. 2nd ed. St Louis: Elsevier, 2018;1319–1322.
4. Gelberman RH, Boyer MI, Brodt MD, et al. The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons: an experimental study on the early stages of tendon-healing in dogs. J Bone Joint Surg Am 1999;81:975–982.
5. Lister GD, Kleinert HE, Kutz JE, et al. Primary flexor tendon repair followed by immediate controlled mobilization. J Hand Surg Am 1977;2:441–451.
6. Kessler I, Nissim F. Primary repair without immobilization of flexor tendon division within the digital sheath. An experimental and clinical study. Acta Orthop Scand 1969;40:587–601.
7. Möller M, Movin T, Granhed H, et al. Acute rupture of tendon Achillis. A prospective randomised study of comparison between surgical and non-surgical treatment. J Bone Joint Surg Br 2001;83:843–848.
8. Gall TT, Santoni BG, Egger EL, et al. In vitro biomechanical comparison of polypropylene mesh, modified three-loop pulley suture pattern, and a combination for repair of distal canine Achilles tendon injuries. Vet Surg 2009;38:845–851.
9. Strickland JW. Development of flexor tendon surgery: twenty-five years of progress. J Hand Surg Am 2000;25:214–235.
10. Dona E, Turner AW, Gianoutsos MP, et al. Biomechanical properties of four circumferential flexor tendon suture techniques. J Hand Surg Am 2003;28:824–831.
11. Guzzini M, Lanzetti RM, Proietti L, et al. Interlocking horizontal mattress suture versus Kakiuchi technique in repair of Achilles tendon rupture: a biomechanical study. J Orthop Traumatol 2017;18:251–257.
12. Dunlap AE, Kim SE, McNicholas WT. Biomechanical evaluation of a nonlocking premanufactured loop suture technique compared to a three-loop pulley suture in a canine calcaneus tendon avulsion model. Vet Comp Orthop Traumatol 2016;29:131–135.
13. Cervi M, Brebner N, Liptak J. Short- and long-term outcomes of primary Achilles tendon repair in cats: 21 cases. Vet Comp Orthop Traumatol 2010;23:348–353.
14. Wilson L, Banks TA, Luckman P, et al. Biomechanical evaluation of double Krackow sutures versus the three-loop pulley suture in a canine gastrocnemius tendon avulsion model. Aust Vet J 2014;92:427–432.
15. Moores AP, Owen MR, Tarlton JF. The three-loop pulley suture versus two locking-loop sutures for the repair of canine Achilles tendons. Vet Surg 2004;33:131–137.
16. Moores AP, Comerford EJ, Tarlton JF, et al. Biomechanical and clinical evaluation of a modified 3-loop pulley suture pattern for reattachment of canine tendons to bone. Vet Surg 2004;33:391–397.
17. Duffy DJ, Main RP, Moore GE, et al. Ex vivo biomechanical comparison of barbed suture and standard polypropylene suture for acute tendon laceration in a canine model. Vet Comp Orthop Traumatol 2015;28:263–269.
18. Krackow KA, Thomas SC, Jones LC. A new stitch for ligament-tendon fixation. J Bone Joint Surg Am 1986;68:764–766.
19. Baltzer WI, Rist P. Achilles tendon repair in dogs using the semitendinosus muscle: surgical technique and short-term outcome in five dogs. Vet Surg 2009;38:770–779.
20. Alavanja G, Dailey E, Mass DP. Repair of zone II flexor digitorum profundus lacerations using varying suture sizes: a comparative biomechanical study. J Hand Surg Am 2005;30:448–454.
21. Taras JS, Raphael JS, Marczyk SC, et al. Evaluation of suture caliber in flexor tendon repair. J Hand Surg Am 2001;26:1100–1104.
22. Barrie KA, Tomak SL, Cholewicki J, et al. Effect of suture locking and suture caliber on fatigue strength of flexor tendon repairs. J Hand Surg Am 2001;26:340–346.
23. Wieskötter B, Herbort M, Langer M, et al. The impact of different peripheral suture techniques on the biomechanical stability in flexor tendon repair. Arch Orthop Trauma Surg 2018;138:139–145.
24. Putterman AB, Duffy DJ, Kersh ME, et al. Effect of a continuous epitendinous suture as adjunct to three-loop pulley and locking-loop patterns for flexor tendon repair in a canine model. Vet Surg 2019;48:1229–1236.
25. Cocca CJ, Duffy DJ, Kersh ME, et al. Biomechanical comparison of three epitendinous suture patterns as adjuncts to a core locking loop suture for repair of canine flexor tendon injuries. Vet Surg 2019;48:1245–1252.
26. Duffy DJ, Cocca CJ, Kersh ME, et al. Effect of bite distance of an epitendinous suture from the repair site on the tensile strength of canine tendon constructs. Am J Vet Res 2019;80:1034–1042.
27. Najibi S, Banglmeier R, Matta J, et al. Material properties of common suture materials in orthopaedic surgery. Iowa Orthop J 2010;30:84–88.
28. Hirpara KM, Sullivan PJ, Raheem O, et al. A biomechanical analysis of multistrand repairs with the Silfverskiold peripheral cross-stitch. J Bone Joint Surg Br 2007;89:1396–1401.
29. Duffy DJ, Chang Y-J, Gaffney LS, et al. Effect of bite depth of an epitendinous suture on the biomechanical strength of repaired canine flexor tendons. Am J Vet Res 2019;80:1043–1049.
30. Hatanaka H, Manske PR. Effect of suture size on locking and grasping flexor tendon repair techniques. Clin Orthop 2000;267–274.
31. Uslu M, Isik C, Ozsahin M, et al. Flexor tendons repair: effect of core sutures caliber with increased number of suture strands and peripheral sutures. A sheep model. Orthop Traumatol Surg Res 2014;100:611–616.
32. Meeson RL, Davidson C, Arthurs GI. Soft-tissue injuries associated with cast application for distal limb orthopaedic conditions. A retrospective study of sixty dogs and cats. Vet Comp Orthop Traumatol 2011;24:126–131.
33. Dy CJ, Hernandez-Soria A, Ma Y, et al. Complications after flexor tendon repair: a systematic review and meta-analysis. J Hand Surg Am 2012;37:543–551.
34. Gelberman RH, Manske PR, Akeson WH, et al. Flexor tendon repair. J Orthop Res 1986;4:119–128.
35. Pruitt DL, Manske PR, Fink B. Cyclic stress analysis of flexor tendon repair. J Hand Surg Am 1991;16:701–707.
