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- Author or Editor: Daniel J. Duffy x
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Abstract
OBJECTIVE
To evaluate effects of loop diameter of a modified Kessler locking-loop (LL) suture on in vitro tensile strength and gapping characteristics of canine flexor tendon repairs.
SAMPLE
48 cadaveric superficial digital flexor tendons from 24 adult medium- to large-breed dogs.
PROCEDURES
Flexor tendons were randomly assigned to 4 groups (n = 12/group) and repaired with 2-0 polypropylene in a LL pattern with loops measuring 1, 2, 3, or 4 mm in diameter. Biomechanical loads, gap formation between tendon ends, and failure modes were evaluated and compared between groups.
RESULTS
Increasing loop diameter from 1 to 4 mm significantly increased yield (P = .048), peak (P < .001), and failure (P < .001) loads. There were no significant differences in yield, peak, and failure loads between 1- and 2-mm loops. Load to 3-mm gap formation was significantly (P < .001) greater for 4-mm loops, compared with 1-, 2-, and 3-mm loops. Failure mode did not differ significantly among experimental groups, with 46 of 48 (96%) of constructs failing because of suture breakage.
CLINICAL RELEVANCE
Loop diameter of a LL suture pattern is an important biomechanical variable that influences construct biomechanics of canine tendon suture repairs. Loop diameters > 3 mm are recommended when the size of the tendon allows. Further studies are necessary to determine the in vivo effect of these findings, particularly the effects on tendon blood supply.
Abstract
OBJECTIVE
To determine the effects of 2-, 4-, 6- and 8-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs in an ex vivo model.
SAMPLE
56 cadaveric gastrocnemius musculotendinous units from 28 adult large-breed dogs.
PROCEDURES
Tendons were randomly assigned to 4 repair groups (2-, 4-, 6- or 8-strand suture technique; n = 14/group). Following tenotomy, repairs were performed with the assigned number of strands of 2-0 polypropylene suture in a simple interrupted pattern. Biomechanical testing was performed. Yield, peak, and failure loads, the incidence of 1- and 3-mm gap formation, forces associated with gap formation, and failure modes were compared among groups.
RESULTS
Yield, peak, and failure forces differed significantly among groups, with significantly greater force required as the number of suture strands used for tendon repair increased. The force required to create a 1- or 3-mm gap between tendon ends also differed among groups and increased significantly with number of strands used. All constructs failed by mode of suture pull-through.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that increasing the number of suture strands crossing the repair site significantly increases the tensile strength of canine gastrocnemius tendon repair constructs and their resistance to gap formation. Future studies are needed to assess the effects of multistrand suture patterns on tendon glide function, blood supply, healing, and long-term clinical function in dogs to inform clinical decision-making.
Abstract
OBJECTIVE
To evaluate the effect of presurgical storage conditions on leakage pressures of enterotomy sites closed with unidirectional barbed suture material in fresh, chilled, and frozen-thawed cadaveric canine jejunal specimens.
SAMPLE
36 grossly normal jejunal segments obtained from 4 dog cadavers.
PROCEDURES
9 jejunal segments were harvested immediately from each euthanized dog and randomly assigned to be tested within 4 hours after collection (fresh segments), stored at 4°C for 24 hours before testing (chilled segments), or stored at −20°C for 7 days and thawed at 21°C for 6 hours before testing (frozen-thawed segments). For leakage pressure testing, a 3-cm-long antimesenteric enterotomy was performed and repaired with 3-0 unidirectional barbed suture material in a simple continuous pattern in each segment. Time to complete the enterotomy, initial leakage pressure, maximum intraluminal pressure, and leakage location were recorded for each segment.
RESULTS
Mean ± SD initial leakage pressure for fresh, chilled, and frozen-thawed segments was 52.8 ± 14.9 mm Hg, 51.8 ± 11.9 mm Hg, and 33.3 ± 7.7 mm Hg, respectively. Frozen-thawed segments had significantly lower mean initial leakage pressure, compared with findings for fresh or chilled segments. Time to complete the enterotomy, maximum intraluminal pressure, and leakage location did not differ among groups.
CONCLUSIONS AND CLINICAL RELEVANCE
Leak pressure testing of cadaveric jejunal segments that are fresh or chilled at 4°C for 24 hours is recommended for enterotomy studies involving barbed suture material in dogs. Freezing and thawing of cadaveric jejunal tissues prior to investigative use is not recommended because leak pressure data may be falsely low.
Abstract
OBJECTIVE
To evaluate the effect of suture caliber on the tensile strength of tenorrhaphies performed with a locking-loop technique in cadaveric canine tendons
SAMPLE
60 superficial digital flexor tendons (SDFTs) from 30 cadaveric adult dogs.
PROCEDURES
Transverse tenotomy was performed, and SDFTs were repaired with a locking-loop technique and polypropylene suture of 5 randomly assigned calibers: size-0, 2-0, 3-0, 4-0, or 5-0 (n = 12 SDFTs/suture caliber). Tendon constructs were tested to failure. Yield, peak, and failure forces and causes of failure were compared between groups.
RESULTS
Mean ± SD failure force for the constructs was significantly greater with large-caliber suture (size-0: 73.5 ± 3.1 N; size 2-0: 54.4 ± 7.1 N; size 3-0: 28.7 ± 4.9 N; size 4-0: 18.7 ± 3.4 N; and size 5-0: 8.8 ± 2.8 N). The likelihood of construct failure by suture pullout through the tendon substance increased with large-caliber suture (size-0: 12/12), whereas the likelihood of construct failure by suture breakage increased with small-caliber suture (2-0: 10/12; 3-0, 4-0, and 5-0: 12/12 each).
CONCLUSIONS AND CLINICAL RELEVANCE
Large-caliber suture had greater tensile strength for tenorrhaphies performed with a locking-loop technique in cadaveric canine tendons. Prior to the use of large-caliber suture in patients requiring tenorrhaphy, however, in vivo studies are required to confirm the results obtained here.
Abstract
OBJECTIVE
To evaluate effects of bite distance of an interlocking horizontal mattress epitendinous suture (IHMES) from the repair site on tensile strength of canine tendon repairs.
SAMPLE
72 canine cadaveric superficial digital flexor tendons (SDFTs).
PROCEDURES
Transverse tenotomy was performed, and SDFTs were repaired with a locking-loop construct (LL construct) or 3 LL constructs with IHMES suture bites placed 5 (LL + 5ES construct), 10 (LL + 10ES construct), or 15 (LL + 15ES construct) mm from the transection site (18 SDFTs/group). Constructs were loaded to failure. Load at 1− and 3-mm gapping, yield force, failure load, and failure mode were evaluated.
RESULTS
Mean ± SD yield force and failure load for LL constructs were significantly lower than for IHMES constructs. Load at 1− and 3-mm gapping was significantly higher for IHMES constructs. Increasing the bite distance significantly increased construct strength (134.4 ± 26.1 N, 151.0 ± 16.8 N, and 182.1 ± 23.6 N for LL + 5ES, LL + 10ES, and LL + 15ES constructs, respectively), compared with strength for the LL construct. Failure mode differed significantly among constructs when an IHMES was used.
CONCLUSIONS AND CLINICAL RELEVANCE
Addition of an IHMES to an LL construct led to increased ultimate tensile strength by 2.5 times and significantly reduced gap formation. Increasing the IHMES bite distance increased yield force by 2.1, 2.3, and 2.7 times for bites placed 5, 10, and 15 mm from the tenotomy, respectively. Positioning an IHMES at a greater distance from the repair site provided superior biomechanical strength for tendon repairs in dogs.
Abstract
OBJECTIVE
To evaluate the effects of using an internal fixation plate to augment primary 3-loop pulley (3LP) repair of canine gastrocnemius tendons (GTs).
SAMPLE
48 cadaveric GTs from 24 adult dogs.
PROCEDURES
GTs were dissected free from other tissues, transected, and randomly assigned to 4 groups (n = 12/group). GTs were repaired with 2-0 polypropylene with a 3LP repair alone or a 3LP repair augmented with a 3-hole veterinary cuttable plate (3VCP), a 5-hole veterinary cuttable plate (5VCP), or a 7-hole veterinary cuttable plate (7VC P). Biomechanical loads, construct stiffness, gap formation, and failure modes were compared between groups.
RESULTS
Yield, peak, and failure loads were all significantly increased for the 5VCP and 7VCP groups, compared with the 3LP alone group. Increasing plate length from 3VCP to 5VCP and from 3VCP to 7VCP increased yield, peak, and failure loads. No differences were found between the 3LP and 3VCP groups with regard to yield and peak loads, but failure load was increased in the 3VCP group. Loads to create 1-mm and 3-mm gaps were significantly greater for the 5VCP and 7VCP groups, compared with the 3LP alone and 3VCP groups. Mode of plate attachment failure differed among groups.
CLINICAL RELEVANCE
Tendon plate augmentation may be a viable surgical option to increase the strength of the tenorrhaphy in dogs. However, in vivo studies evaluating the effects of plate augmentation on the tendon blood supply and progression of healing are needed prior to clinical application.
Abstract
OBJECTIVE
To evaluate the influence of superficial digital flexor tendon (SDFT) graft augmentation on the biomechanical properties and resistance to gap formation in a canine gastrocnemius tendon repair model.
SAMPLE POPULATION
28 canine cadaveric hind limbs.
PROCEDURES
Respective hindlimbs from each dog were randomized to one of two groups (n = 14/group) using a 3-loop–pulley (3LP) pattern alone or 3LP + SDFT graft augmentation. Biomechanical parameters evaluated included yield, peak, and failure loads; tensile loads required to create 1- and 3-mm gap formations; and mode of construct failure.
RESULTS
Mean yield and failure loads for the 3LP + SDFT graft group were 483.6 ± 148.0 N and 478.3 ± 147.9 N, respectively, and were greater compared to the 3LP group (34.2 ± 6.7 N and 34.0 ± 8.0 N, P < .0001). Loads to both 1- and 3-mm gap formations for the 3LP + SDFT graft group were greater compared to 3LP alone (P < .001). Failure modes did not differ between groups (P = .120), with constructs failing most commonly by suture pulling through opposed tendinous tissues whereas SDFT grafts remained intact.
CLINICAL RELEVANCE
SDFT graft augmentation increased yield, peak, and failure forces 14-fold across all examined biomechanical variables compared to the 3LP group. The 3LP + SDFT graft group required 3.6X and 6.5X greater loads to cause a 1- and 3-mm gap, respectively, between tendon ends. These data support the biomechanical advantages of SDFT graft augmentation to increase repair-site strength and to promote resistance to gap formation of the tenorrhaphy. Additional in vivo studies are required to determine the effect of SDFT augmentation on clinical function and active limb use after graft harvest in dogs.
Abstract
OBJECTIVE
To evaluate the effect of a double Krackow suture pattern (DK), with and without epitendinous suture augmentation (ES), in a canine gastrocnemius tendon (GT) model.
SAMPLE
Paired GTs from 12 adult dog cadavers and 4 control GT.
PROCEDURES
GTs were assigned to 2 groups (n = 12/group). Transverse tenotomy was performed and repaired with a DK or DK + ES. Yield, peak, and failure force, stiffness, occurrence of 1-and 3-mm gapping, and failure mode were examined.
RESULTS
Yield, peak, and failure loads were greater for DK + ES. Yield force was 48% greater for DK + ES (mean ± SD, 149.56 ± 53.26 N) versus DK (101.27 ± 37.17 N; P = 0.017). Peak force was 45% greater for DK + ES P < 0.001). Failure force was 47% greater for DK + ES (193.752 ± 31.43 N) versus DK (131.54 ± 22.28 N; P < 0.001). Construct stiffness was 36% greater for DK + ES (P = 0.04). All 12 DK and 10 of 12 DK + ES repairs produced a 1-mm gap, with all DK and 4 DK + ES repairs producing a 3-mm gap (P < 0.001). Loads required to create a 3-mm gap were significantly greater for DK + ES (P < 0.013). Suture breakage occurred in all DK repairs, which differed from DK + ES, where suture breakage (7/12) and tissue failure (5/12; P = 0.037) predominated.
CLINICAL RELEVANCE
Augmentation of a primary DK repair with an ES significantly improved construct strength in canine GT constructs while increasing loads required to cause 1- and 3-mm gap formation, respectively. ES augmentation is a simple technique modification that can be used to significantly increase construct strength, compared with DK alone.
