Biomechanical comparison of canine median sternotomy closure using suture tape and orthopedic wire cerclage

OBJECTIVE

To compare the mechanical properties of suture tape and orthopedic wire cerclage in an ex vivo canine median sternotomy model.

STUDY DESIGN

Ex vivo.

ANIMALS

Twelve large-breed canine cadaveric sternums.

METHODS

Median sternotomies were performed, leaving the manubrium intact. The specimens were randomly assigned to group W (20-gauge stainless steel orthopedic wire cerclage in a figure-of-eight pattern) or group ST (suture tape in a figure-of-eight pattern). Each specimen was laterally distracted until failure using an electrodynamic materials-testing system.

RESULTS

No differences were observed for displacement, yield load, maximum load, implant failure between the groups. The orthopedic wire construct was stiffer than the suture tape construct.

CONCLUSION

Suture tape was biomechanically similar to orthopedic wire cerclage for sternotomy closure in dogs, although wire constructs were stiffer.

CLINICAL SIGNIFICANCE

Suture tape may represent an alternative to cerclage wire for sternotomy closure in dogs. Additional studies evaluating its clinical use are needed.

Clinical evaluation of suture materials for transtibial pullout repair of medial meniscus posterior root tear

BACKGROUND

There are no recommendations for specific suture materials in transtibial pullout repair of medial meniscus posterior root tears. This study aimed to evaluate the clinical outcomes of transtibial pullout repair of medial meniscus posterior root tears using ultrahigh-molecular-weight polyethylene sutures and suture tape.

METHODS

We retrospectively reviewed the data of 36 patients (27 women and 9 men, mean age 64.1 years) who had undergone transtibial pullout repair of medial meniscus posterior root tears between November 2018 and December 2019. Two groups of 18 patients each received either two different cord-like sutures or suture tape. Clinical parameters were assessed preoperatively and on second-look arthroscopy (mean postoperative period 12 months). The meniscal healing status was assessed using a previously published scoring system (ranging from 0 to 10), and the incidence rate of suture cut-out was assessed on second-look arthroscopy.

RESULTS

All clinical scores significantly improved in both groups, with no significant between-group differences on second-look arthroscopy. The arthroscopic meniscal healing scores significantly differed between sutures (mean 6.7 points) and suture tape (mean 7.4 points; p = 0.044). No significant between-group difference in the suture cut-out rate was observed.

CONCLUSIONS

This study found no significant differences in the clinical outcomes between ultrahigh-molecular-weight polyethylene sutures and suture tape. Favorable clinical outcomes were obtained using both types of suture; however, the usefulness of suture tape appears to be limited.

Arthroscopic-Assisted Toggle Rod Stabilization in Canine Coxofemoral Luxation: A Cadaveric Study

OBJECTIVE

 The aim of this study was to describe an arthroscopic-assisted technique for coxofemoral toggle rod placement, and to report on the feasibility, drill tunnel trajectory and accuracy of tunnel aperture location using this method.

STUDY DESIGN

 Cadaveric pilot study.

SAMPLE POPULATION

 Eight coxofemoral joints.

METHODS

 Craniodorsal coxofemoral joint luxations were artificially created. A simulated open hip reduction and stabilization with a toggle rod were performed through a limited arthrotomy under arthroscopic guidance. Computed tomography scans were performed to evaluate drill hole trajectory across the femoral neck, and joints were disarticulated and photographed. Digital imaging software was used to determine the percent overlap of the drill hole apertures relative to the origin and insertion of the round ligament on the acetabulum and fovea.

RESULTS

 The exit point of the tunnel was entirely within the fovea capitis in five of eight femurs, three of eight femoral drill apertures were only partially within the target area. Of the eight acetabular bone tunnels examined, all were centred occupying the acetabular fossa.

CONCLUSIONS

 Coxofemoral toggle rod placement can be performed under arthroscopic guidance through a limited arthrotomy. Comparable femoral tunnel accuracy with the standard open technique should be achieved with the current method prior to its clinical use.

Arthroscopic Meniscal Healing following Medial Meniscus Posterior Root Repair: A Comparison between Two Suture Materials

Recently, transtibial pullout repair of the medial meniscus (MM) posterior root tear (PRT) has become widely accepted and provides satisfactory clinical outcomes. Widening after cyclic loading or ultimate failure load using different suture materials and configurations has been studied. However, no study has compared the clinical outcomes using different suture materials. This study aimed to evaluate the clinical outcomes after performing MMPRT pullout repair using different suture materials. We hypothesized that better clinical outcomes would be achieved using ultra-high molecular weight polyethylene (UHMWPE) tape compared with a normal polyester suture. Thirty-seven patients who underwent MM posterior root repair between November 2019 and May 2020 were retrospectively investigated. Pullout repair was performed using a hollow no. 0 polyester suture (n = 14) and UHMWPE tape (n = 23). Clinical outcomes were assessed preoperatively and at 1 year postoperatively, using the Lysholm knee score, Knee Injury and Osteoarthritis Outcome Score, and visual analogue scale (VAS) pain score. The meniscal healing status was assessed using an arthroscopic scoring system (range: 0-10). All clinical scores were improved significantly in both groups. However, significantly higher meniscal healing scores and decreased VAS pain scores were observed in the UHMWPE group (7.3 ± 0.9 and 7.7 ± 11.3, respectively) than in the polyester group (5.6 ± 2.1 and 18.4 ± 18.6, respectively; p < 0.01). Suture cut-out and loss of the root continuity were observed in some cases (three cases [21.4%] in the polyester suture group and one case [4.3%] in the UHMWPE tape group). Both suture materials led to satisfactory clinical outcomes at 1 year postoperatively, whereas the UHMWPE tape was useful for obtaining good meniscal healing and decreasing the VAS pain score.

Surgical stabilization of traumatic elbow joint luxation and proximal ulnar fracture in a silvery langur (Trachypithecus cristatus)

CASE DESCRIPTION

A 3-year-old 5-kg sexually intact female silvery langur housed in a single-species group at a zoological institution was presented because of acute trauma to the left forelimb.

CLINICAL FINDINGS

Radiography of the left forelimb revealed a type II Monteggia fracture (proximal ulnar fracture with cranial displacement and caudal luxation of the radial head). During surgery, disruption of the annular ligament and rupture of the lateral collateral ligament were noted.

TREATMENT AND OUTCOME

The langur underwent open reduction and internal fixation of the ulnar fracture and placement of a radioulnar positional screw, a prosthetic lateral collateral ligament, and a temporary hinged type 1A external skeletal fixator. The langur was returned to group housing, underwent behavioral training, and was periodically anesthetized for physical therapy sessions to improve range of motion of the left elbow joint. The external skeletal fixator was removed 4 weeks after surgery, and the radioulnar positional screw was removed 6 weeks after surgery. Three months after surgery, the range of motion of the langur's left elbow joint was considered normal, and the animal returned to normal activity.

CLINICAL RELEVANCE

For the captive silvery langur of the present report, surgical stabilization and postoperative management of a type II Monteggia fracture of the left forelimb were successful with recovery of elbow joint function. These techniques may be applied to other captive nonhuman primates, including those that brachiate or are members of social species that must be housed with conspecifics in the postoperative period to maintain group dynamics.

Inverted V-shaped extracapsular stabilisation technique and arthroscopic findings in six dogs with medial shoulder instability

OBJECTIVES

The aim of this case series was to report arthroscopic findings and to evaluate clinical outcomes of dogs treated with an inverted V-shaped extracapsular stabilisation technique without additional external coaptation for medial shoulder instability.

MATERIAL AND METHODS

Medical records of dogs with medial shoulder instability that underwent arthroscopy and an inverted V-shaped extracapsular stabilisation technique were retrospectively reviewed. Extracapsular stabilisation was performed in all dogs using screws and spiked washers as anchor points for the coated polyester prosthetic ligament. No additional external coaptation was used in any dog. A minimum 18-month follow-up period was required for study inclusion. Complications and long-term outcomes were recorded.

RESULTS

The subscapularis tendon and medial glenohumeral ligament were the structures most commonly affected. All dogs had pathological cartilage fibrillations. Implants were successfully placed in all dogs. Implant loosening was recorded in two out of six dogs on recheck but no revision surgery was performed. Function at the time of last clinical follow-up (median, 28 months, range 18 to 33 months) was full in four out of six and acceptable in two out of six dogs.

CLINICAL SIGNIFICANCE

Surgical treatment of medial shoulder instability using the novel inverted V-shaped extracapsular stabilisation technique was successful. Potential complications such as implant loosening may occur. Despite the limited number of cases, the present study suggests that additional postoperative external coaptation may not be necessary for successful management of dogs with medial shoulder instability.

Complications and outcomes of cats with coxofemoral luxation treated with hip toggle stabilization using ultrahigh-molecular-weight-polyethylene or nylon (2009-2018): 48 cats

OBJECTIVE

To report overall rate and type of complications and outcomes of cats with coxofemoral luxation managed with hip toggle stabilization (HTS), to compare rate of postoperative complications and outcomes of cats treated with ultrahigh-molecular-weight-polyethylene (UHMWPE) or nylon, and to identify risk factors for reluxation and non-excellent outcomes.

STUDY DESIGN

Multi-institutional retrospective cohort study.

SAMPLE POPULATION

Forty-eight client-owned cats.

METHODS

Medical records of cats that underwent HTS from 2008-2018 using UHMWPE or nylon were reviewed. Univariable and multivariable logistic regression was performed to assess for factors associated with reluxation and non-excellent outcome. Final outcome was obtained from owner questionnaire.

RESULTS

Intraoperative and postoperative complications were recorded in two (4.2%) and 11 (24.4%) cats, respectively. The most common postoperative complication was reluxation (n = 5 [11.1%]). Outcome was classified as excellent in 81.1% and good in 16.2% of cats after a median of 445.5 days (range, 53-3720). No difference in rate of complications or outcomes was identified between UHMWPE and nylon. Performance of additional orthopedic procedures, occurrence of intraoperative complications, and non-performance of capsulorrhaphy were associated with reluxation. Performance of additional non-hip procedures (orthopedic/nonorthopedic) was associated with non-excellent outcome.

CONCLUSION

Hip toggle stabilization was associated with a low rate of intraoperative complications and reluxation and excellent long-term outcomes in most cats. No difference in rate of postoperative complications or outcomes of cats treated using UHMWPE or nylon was identified. Cats that underwent additional orthopedic procedures had greater risk of reluxation.

CLINICAL SIGNIFICANCE

Hip toggle stabilization is an effective technique for management of coxofemoral luxation in cats. Comparable results are expected using UHMWPE or nylon.

FiberWire vs FiberTape: Comparison of Bacterial Adherence in a Murine Air Pouch Wound Model

Background:

For high–tensile strength sutures, past research has largely focused on mechanical properties or bacterial adherence across various manufacturers.

Purpose:

This study investigated high-tensile strength sutures with different shapes but otherwise identical composition. The purpose was to evaluate the differences between high–tensile strength suture wire and suture tape relative to bacterial adherence and bacterial retention after washout.

Study Design:

Controlled laboratory study.

Methods:

Sutures were implanted in dorsal air pouches of 72 BALB/cJ mice. Experimental pouches were inoculated with Staphylococcus aureus; no bacteria were used in the control conditions. The mice were randomized into 3 groups: group 1 underwent suture extraction 7 days after implantation; group 2 underwent an irrigation procedure, followed by immediate suture extraction on day 7; and group 3 underwent an irrigation procedure on day 7, with delayed suture extraction on day 14 after implantation. The sutures were evaluated using confocal microscopy; electron microscopy; and spectrophotometry, through which optical density, as measured by the amount of scattered light, is directly correlated with the number of bacteria. Histological assessment was performed on the pouches.

Results:

Optical density (mean ± SD) was significantly higher for FiberTape sutures than for FiberWire sutures, respectively, at the 2-hour time point for all groups (group 1, 0.0550 ± 0.0081 vs 0.0162 ± 0.006 [P = .0054]; group 2, 0.0225 ± 0.0049 vs 0.0056 ± 0.0006 [P = .0045]; group 3, 0.055 ± 0.0222 vs 0.0043 ± 0.0005 [P = .0103]). Additionally, groups 2 and 3 showed statistically significant results at the 4-hour time points (group 2, 0.0384 ± 0.0087 vs 0.0145 ± 0.0042 [P = .0280]; group 3, 0.0532 ± 0.0159 vs 0.0101 ± 0.0025 [P = .0058]). The wash fluid also demonstrated significantly greater optical density for the FiberTape than the FiberWire sutures, respectively, at the 2-hour time point for all groups (group 1, 0.1657 ± 0.0319 vs 0.0317 ± 0.008 [P = .0063]; group 2, 0.0522 ± 0.0156 vs 0.0127 ± 0.0022 [P = .0219]; group 3, 0.1707 ± 0.0205 vs 0.0191 ± 0.0053 [P < .0001]). No bacterial growth occurred in the control conditions. Histological assessment revealed only mild inflammation in the control groups as compared with more severe responses in the experimental groups at all time points.

Conclusion:

FiberTape was associated with increased bacterial adhesion as well as retention as compared with FiberWire in an in vivo murine wound model.

Clinical Relevance:

This study demonstrates that suture design influences the occurrence of and ability to clear surgical infection and must be considered when selecting high-tensile strength sutures in a clinical setting.

Crimped monofilament nylon leader for median sternotomy closure in 10 dogs

OBJECTIVE

To describe and report the outcomes after closure of median sternotomies with crimped monofilament nylon leader (MNL) in dogs.

STUDY DESIGN

Retrospective observational study.

ANIMALS

Dogs (n = 10) that underwent intrathoracic surgery through a median sternotomy approach.

METHODS

The median sternotomy was closed in a peristernal figure eight pattern with crimped MNL. Medical records were reviewed for clinical and histopathological findings and complications. Owners or veterinarians were contacted to collect long-term follow-up information.

RESULTS

The technique was simple, with no intraoperative complications. Postoperative infection was documented in one dog, requiring removal of a single MNL and associated crimp clamp. Delayed healing of the surgical incision in one dog was managed conservatively. No other complications were documented throughout long-term follow-up at a median of 488 days (range, 199-608).

CONCLUSION

Median sternotomies were successfully closed with crimped MNL and were associated with a low complication rate.

CLINICAL SIGNIFICANCE

Crimped MNL represents an alternative method to close median sternotomies in dogs.

Ex vivo mechanical properties of a 2.5-mm bone anchor for treatment of cranial cruciate ligament rupture in toy breed dogs

OBJECTIVE

To determine the mechanical pull-out properties of a 2.5-mm bone anchor implanted in ex vivo femurs of toy breed dogs and to determine whether there is a difference between knotted and knotless configurations.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Eight paired harvested femurs.

METHODS

Femurs were assigned to knotted or knotless configuration. Equal numbers of right and left femurs were tested. The caudolateral femoral condyle at the distal pole of the lateral fabella (F2 site) was drilled. The assigned configuration with braided suture combined with the bone anchor was implanted into the F2 site. Each configuration was positioned into a mechanical testing machine to measure yield load, load at 3-mm displacement, ultimate load, stiffness, and mode of failure at the beginning of the canine standing phase angle (150°).

RESULTS

Mean ultimate load was 100.14 and 88.69 N (P = .798), mean yield load was 59.72 and 55.85 N (P = .708), load at 3-mm displacement was 46.72 and 43.33 N (P = .656), and stiffness was calculated to be 43.06 and 47.09 N/mm (P = .548) for knotted and knotless configurations, respectively. Mode of failure occurred primarily by anchor pull-out.

CONCLUSION

The bone anchor withstood deformation at the estimated forces applied on the native cranial cruciate ligament (CCL) of toy breed dogs in both configurations.

CLINICAL SIGNIFICANCE

This bone anchor may constitute a useful alternative for stabilization of the CCL deficient stifle in toy breed dogs. However, before it can be recommended for widespread use in dogs, closely monitored clinical trials must be conducted to assess outcome and complications associated with this implant.

Coxofemoral Joint Luxation in Dogs Treated with Toggle Rod Stabilization: A Multi-Institutional Retrospective Review with Client Survey

Coxofemoral luxation is the most common type of joint luxation observed clinically in dogs. This retrospective study determines the complications and outcomes of open reduction and internal fixation of coxofemoral luxations using a toggle rod stabilization in 58 dogs. The purpose of the study was to compare the results with previous studies to ascertain commonalities and differences. A majority of the canine luxations were stabilized using a 4.0 or 3.2 mm commercial toggle rod and either one or two strands of OrthoFiber, FiberWire, or monofilament nylon suture. Postoperative complications developed in 25 of the 58 (43%) dogs, with major complications in 9 cases (15.5%). The most common major complication was reluxation, which occurred in 6 dogs (10%). Five of the 6 cases of reluxation received monofilament suture, although there was not a statistically significant relationship between suture type and reluxation. Owner responses to a questionnaire reported good to excellent results for satisfaction with the procedure in 90% of cases. Results of the present study suggest that toggle rod stabilization remains an effective method for the treatment of coxofemoral joint luxation in dogs.

Biomechanical comparison of four prosthetic ligament repair techniques for tarsal medial collateral ligament injury in dogs

OBJECTIVE

To compare joint stability and ultimate strength among 4 prosthetic ligament constructs for repair of tarsal medial collateral ligament (MCL) injury in dogs.

SAMPLE

13 canine cadavers (26 hind limbs).

PROCEDURES

Each limb was stripped of all soft tissues except those associated with the tarsal joint and assigned to 1 of 4 prosthetic ligament constructs. The AN construct consisted of 3 bone anchors connected with monofilament nylon suture. The AU construct consisted of low-profile suture anchors connected with multifilament ultrahigh-molecular-weight polyethylene (UHMWPE) suture. The TN and TU constructs involved the creation of 3 bone tunnels and use of nylon or UHMWPE suture, respectively. Each limb underwent biomechanical testing before and after MCL transection and before and after cyclic range-of-motion testing following completion of the assigned construct. Tarsal joint stability (extent of laxity) was assessed with the joint in each of 3 positions (75°, 135°, and 165°). After completion of biomechanical testing, each limb was tested to failure to determine the ultimate strength of the construct.

RESULTS

Relative to intact tarsal joints, joint laxity was significantly increased following completion of all 4 constructs. Construct type was not associated with the magnitude of change in joint laxity. Ultimate strength was greatest for the UHMWPE-suture constructs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that all 4 constructs effectively stabilized MCL-deficient tarsal joints. Implants used for the TU, TN, and AU constructs had a lower profile than those used for the AN construct, which may be clinically advantageous. In vivo studies are warranted.

Innovative, intra-articular, prosthetic technique for cranial cruciate ligament reconstruction in dogs: a cadaveric study

The purpose of this study was to describe and assess the feasibility of a new intra-articular approach in the treatment of cranial cruciate ligament deficiency in dogs using an artificial ligament and a new bone-anchor system. Twelve canine cadavers weighting 26 to 45 kg were used in this ex-vivo study. Special tibial and femoral screws, two helicoils, and a high resistance artificial fiber compose the implant. Surgery was performed using the cranio-lateral approach to the stifle joint. Helicoil and tibial screw, connected to the fiber, were inserted in the center of the tibial insertion area of the cranial cruciate ligament. The fiber was passed over-the-top, tensioned, and fixed to the femoral screw, previously inserted with the helicoil in the distal part of the femur. Surgery was completed in all the cases. Occasional problems found during the insertion of the helicoils and screws were resolved with simple procedures. Post-operative clinical assessment showed negative cranial drawer test, negative cranial tibial thrust, and normal range of motion. Radiographic evaluation showed an appropriate positioning of both tibial and femoral implants in all the cases. The results of the first surgical appraisal of this new technique are encouraging, although further studies are necessary to demonstrate the in vivo efficacy of this procedure.

The effects of a novel lateral extracapsular suture system on the kinematics of the cranial cruciate deficient canine stifle

Objective To evaluate the relative position of the femur and tibia in cranial cruciate ligament- intact stifles, cranial cruciate ligamentdeficient stifles, and cruciate-deficient stifles following lateral extracapsular suture system (LESS) stabilization under load at specific joint angles.

Study design In vitro biomechanical study.

Methods Twenty pelvic limbs from 11 dogs were used to evaluate the relative position of the femur and tibia between three stifle conditions (cranial cruciate ligament-intact, cranial cruciate ligament-deficient, and LESSstabilized) at a load of 30% of body weight and stifle angles of 125°, 135°, and 145° using electromagnetic tracking sensors.

Results Cranial cruciate ligament-deficient stifles had significantly greater (p <0.0001) cranial displacement and internal rotation of the tibia relative to the femur than cranial cruciate ligament-intact or LESS stifles at all stifle angles. Cranial displacement of the tibia relative to the femur for cranial cruciate ligament-intact and LESS stifles were not significantly different from one another at a stifle angle of 125°, but were significantly different at stifle angles of 135° (p = 0.0182) and 145° (p = 0.0012). There was no significant difference in internal rotation of the tibia relative to the femur between the cranial cruciate ligament-intact and LESS stifles at any of the stifle angles.

Clinical significance The LESS procedure effectively decreased cranial tibial displacement and eliminated internal rotation of the tibia relative to the femur in the cranial cruciate ligament-deficient stifles at stifle angles of 125°, 135°, and 145° in vitro.

A review of extra-articular prosthetic stabilization of the cranial cruciate ligament-deficient stifle

Extra-articular prosthetic stabilization techniques have been used as a method of stabilization of the cranial cruciate ligament (CrCL)-deficient stifle for decades. During extra-articular prosthetic stabilization, the prosthesis is anchored to the femur and tibia, and tensioned in the attempt to resolve femorotibial instability. The position of the anchor points of the prosthesis is crucial for restoring a normal range of joint motion and mitigating alterations in prosthesis tension during motion. Recently developed techniques offer several innovations with potential advantages such as bone-to-bone fixation, prosthetic materials with better mechanical properties, and improved isometry of the anchor points. Whether these innovations provide clinically superior results to the traditional techniques such as lateral circumfabellar-tibial suture techniques has yet to be determined.

Correction of craniodorsal coxofemoral luxation in cats and small breed dogs using a modified Knowles technique with the braided polyblend TightRope™ systems

Objectives: To report the surgical technique and short-term radiographic and functional outcome data for a series of client owned, small breed dogs and cats treated for traumatic craniodorsal coxofemoral luxation using open reduction and internal fixation with the Arthrex Mini TightRope (mTR) and TightRope (TR) systems.

Methods: Data were collected retrospectively from the clinical case records, including the initial clinical and radiographic findings, surgical technique, and postoperative short-term clinical and radiographic data. Functional data collected after the six weeks reassessment were obtained via owner questionnaire.

Results: Four cats (mTR = 4) and five small breed dogs (mean weight 15 kg; TR = 4, mTR = 1) were included. Median time to postoperative weight bearing was one day. Median lameness score at six weeks postoperatively was 0 out of 5. Coxofemoral joint congruity was radiographically confirmed at the six weeks postoperative visit. Telephone follow-up (at a median of 16 weeks) revealed all animals had returned to their previous level of activity. Complications were minor, and limited to postoperative swelling (n = 1).

Clinical significance: Clinical use of the Arthrex Mini TightRope™ and TightRope™ systems can be recommended for traumatic craniodorsal coxofemoral luxation in this novel application as short-term results are at least comparable to existing surgical techniques. Long-term follow-up studies are needed.

Use of a novel extracapsular bone anchor system for stabilisation of cranial cruciate ligament insufficiency

OBJECTIVES

To evaluate early clinical experiences using the novel extracapsular bone anchor Ruby system for stabilisation of the cranial cruciate ligament deficient stifle in the dog and report short-term outcome and complications for 17 clinical cases.

MATERIALS AND METHODS

Seventeen dogs with cranial cruciate ligament insufficiency were treated using the Ruby system. Dogs were eligible if diagnosed via orthopaedic examination with unilateral or bilateral cranial cruciate ligament instability without any comorbidities. Subjective lameness assessments on a 0 to 4 scale were made pre-operatively and at six to eight weeks post-operatively; complications were also recorded. Lameness was also assessed on a visual analogue scale at six to eight months post-operatively.

RESULTS

All cases had substantial improvement in lameness following surgery. Mean post-operative lameness grade was 1·18 (±0·53) out of 4, compared to a grade of 3·06 (±0·9) before surgery, and owner assessment at six to eight months after surgery was also positive. There were major complications that required surgical intervention in one dog.

CLINICAL SIGNIFICANCE

The Ruby system is a feasible method of extracapsular stabilisation with comparable outcomes and complication rates to previously reported methods of addressing cranial cruciate ligament insufficiency. Further work is required to acquire more data on objective outcome measurement and mechanisms of failure.

Biomechanical evaluation of different suture materials for arthroscopic transtibial pull-out repair of posterior meniscus root tears

PURPOSE

To evaluate the biomechanical properties of four different suture materials for arthroscopic transtibial pull-out repair of posterior meniscus root tears, with special focus on the meniscus-suture interface.

METHODS

Forty fresh-frozen lateral porcine menisci were used. The posterior meniscus root was sutured in a standardized fashion with a simple stitch using four different suture materials: group A, No. 2 PDS™; group B, No. 2 Ethibond™; group C, No. 2 FiberWire™; and group D, 2-mm Fibertape™. Meniscus-suture constructs were subjected to cyclic loading followed by load-to-failure testing using a servo-hydraulic material testing machine.

RESULTS

During cyclic loading, group D showed a significantly higher displacement after 100, 500, and 1,000 cycles compared to group A (p < 0.001, p = 0.001, and p = 0.001), and a significantly higher displacement after 100 and 500 cycles compared to group B (p = 0.010 and p = 0.045). Group C showed a significantly higher displacement compared to group A after 100 cycles (p = 0.008). The highest maximum load was observed in group D, with significant differences compared to group A (p = 0.013). Group B showed a significantly higher stiffness compared to group A (p = 0.023), and both group C and group D showed a significantly higher stiffness compared to group A and group B (p < 0.001).

CONCLUSION

None of the evaluated suture materials provided clearly superior properties over the others during both cyclic loading and load-to-failure testing. Based on the results of this study, FiberWire™ may be the preferred suture material for transtibial pull-out repair of posterior meniscus root tears because of comparably low displacement during cyclic loading and high values for maximum load and stiffness. In the clinical setting, FiberWire™ may improve healing rates and avoid progressive extrusion of the meniscus after transtibial pull-out repair of posterior meniscus root tears.

Mechanical comparison of 3 anchoring techniques in the muscular process for laryngoplasty in the equine larynx

OBJECTIVE

To compare mechanical properties of 2 techniques with a conventional technique for anchoring the muscular process in a laryngoplasty procedure.

STUDY DESIGN

Experimental ex vivo study.

SAMPLE POPULATION

Equine larynges (n = 60).

METHODS

A single loop (SL), a screw (SC), and a double loop technique (DL) were compared. Constructs were subjected to cyclic loading, oscillating from 5 to 50 N for 3000 cycles, followed by a single cycle to failure test. Mean distraction, load at failure, stiffness, and failure mode were compared between groups.

RESULTS

Mean ± SD distraction in cyclic loading was greater for DL (2.1 ± 0.7 mm) than for SL (1.9 ± 1.3 mm) and SC (1.539 ± 0.9 mm); however, there was no significant difference between SL and SC or between SL and DL. Mean ultimate failure load was greater for DL (240 ± 44.56 N) than for SC (189.59 ± 46.16 N) and SL (150.93 ± 44.43 N) and greater for SC compared with SL. Failure occurred by cartilage tearing for DL and SL, and by screw pull out (n = 13) or knot slippage (4) for SC.

CONCLUSION

In cyclic loading, SC is more stable than DL and at least as stable as SL. In single cycle to failure, DL is the strongest construct and SC is stronger than SL.

Mechanical testing of newly developed biomaterial designed for intra-articular reinforcement of partially ruptured cranial cruciate ligament: ex vivo pig model

The study deals with mechanical testing of newly developed material polyethylene terephtalate coated with polycaprolactone nanofibers in combination with biodagradable Hexalon ACL/PCL screws as a new possibility of intra-articular reinforcement of partially ruptured cranial cruciate ligament. Four groups ofex vivomodels of pig stifle joints were prepared and tested: a model with intact CCL (group 1), a model with partial CCL rupture (group 2), a model with CCL rupture stabilized with 7 mm Mersilene®strip (group 3), and a model with CCL rupture stabilized with 5 mm PET/PCL biomaterial strip (group 4). The models were loaded in the standing angle of 100° and the maximum load (N) and the shift (mm) were monitored. The mean maximum peak power and the shift were 1266.0 ± 146.9 N and 13.7 ± 2.5 mm for group 1, and 1164.7 ± 228.2 N and 1 6.8 ± 3.3 mm for group 2, respectively. In all cases after reaching the maximum load, a tibial fracture occurred but never a CCL rupture. In groups 3 and 4, the initial fixation failure occurred in the mean values of 375.7 ± 81.5 and 360.4 ± 52.0 N, respectively, and with a bigger shift of 52.3 ± 11.9 mm and 39.4 ± 14.6 mm, respectively, compared to group 1. A critical point of failure was the anchoring in the bone. It can be concluded that the PET/PCL substitute in theex vivomodel has mechanically comparable properties with the clinically used Mersilene®,and based on its proven ability to carry stem cells it could be appropriate for partially ruptured CCL protection.

Effect of configuration on the biomechanical performance of three suture materials used in combination with a metallic bone anchor

OBJECTIVE

To determine whether different suture configurations could improve the biomechanical performance of 3 suture materials used with bone anchors.

SAMPLES

3 suture materials (60-lb test nylon leader line, size 2 polyblend polyethylene composite suture, and 150-lb test ultrahigh-molecular weight spun polyethylene). PROCEDURES-Each suture material was looped through the eyelet of a metallic bone anchor and constructs were evaluated by use of an acute uniaxial load. Three configurations were tested for each suture material: single stranded (SS), double stranded (DS), and single stranded plus plastic insert (SSP). Force at failure, extension at failure, force at 3 mm of extension, stiffness, and site of failure of the suture were recorded for each test.

RESULTS

For all sutures, the DS configuration was the stiffest and yielded significantly higher forces at failure and forces at 3 mm of extension. The SS configuration had the lowest forces at failure. The SSP configuration yielded greater forces at failure for all suture materials, compared with the SS configuration, with a comparable stiffness. All sutures failed at the eyelet in the SS and DS configurations. In the SSP configuration, 60-lb test nylon leader line and 150-lb test ultrahigh-molecular weight spun polyethylene failed at the eyelet less frequently than did the polyblend composite suture.

CONCLUSIONS AND CLINICAL RELEVANCE

Among the tested constructs, a DS suture configuration used in combination with the metallic bone anchor gave the best biomechanical results for all suture materials. Considering that the SSP configuration yielded greater forces at failure, compared with the SS configuration, covering metallic edges in bone anchors with softer materials might protect sutures and result in increased forces at failure.

Assessment of the craniocaudal stability of four extracapsular stabilization techniques during two cyclic loading protocols: a cadaver study

OBJECTIVE

To (1) compare the effect of cyclic loading on craniocaudal tibial translation in cranial cruciate ligament (CrCL)-deficient stifles after extracapsular stabilization, and (2) evaluate the effect of peak force during cyclic loading on the rate of development of craniocaudal laxity.

STUDY DESIGN

Biomechanical cadaveric study.

SAMPLE POPULATION

Cadaveric pelvic limbs (n = 24 pairs) from skeletally mature dogs.

METHODS

Twenty-four pairs of stifles were randomly assigned to 4 stabilization groups: nylon leader lateral circumfabellar-tibial suture (NLS); FiberTape lateral circumfabellar-tibial suture (FTLS); TightRope (TR); or bone anchor (BA). Contralateral limbs were cyclically loaded to produce cranial tibial translation at peak forces of either 80 or 160 N. Craniocaudal displacement of the tibia was measured with a mechanical testing machine during cyclic loading with the CrCL intact, after CrCL transection, and after extracapsular stabilization. The number of cycles each construct underwent before reaching 200% and 300% of the mean craniocaudal displacement present during cyclic loading of the CrCL-intact stifles was calculated. Number of cycles among treatment groups was compared with a Kruskal-Wallis test. P < .05 was considered significant.

RESULTS

Mean ± SD translation before and after CrCL transection were 3.9 ± 0.6 and 14.6 ± 1.7 mm, respectively. TR constructs resisted significantly more cycles than NLS constructs before reaching 7.8 mm (200%) and 11.7 mm (300%) of translation when loaded to 80 N. No other differences between constructs were significant at a peak load of 80 N. All constructs reached 7.8 and 11.7 mm of translation in fewer cycles when loaded to 160 N than at 80 N.

CONCLUSIONS

TR constructs were most resistant to elongation during cyclic loading. Doubling the peak force during cyclic loading significantly decreased the number of cycles constructs withstood, supporting recommendations for restricting postoperative activity after extracapsular stabilization of the CrCL-deficient stifle.

Retrospective Study Comparing Two Materials Commonly Used in the LFS Technique for CCLR

Cranial cruciate ligament rupture (CCLR) is the most common cause of degenerative joint disease (DJD) in the stifle of adult dogs. Over the last several years, a new generation of nonabsorbable, multifilament, polyblend polyethylene orthopedic suture materials have been evaluated for use in the lateral fabellar suture (LFS) technique for surgical treatment of CCLR. This retrospective study compared the short-term outcome of 16 dogs that were treated using the LFS technique using either a proprietary polyblend polyethylene orthopedic suture material (FW) or monofilament nylon leader line (NLL). The FW was significantly more likely to fail compared with the NLL (P = 0.0379). Specifically, the FW was 14.667 times likelier to fail than the NLL. When one and two strands of NLL were compared with FW, the FW was 6 times more likely to fail than one strand of NLL and 32 times more likely to fail than two strands of NLL. To the authors’ knowledge, this is the first study comparing the two materials used in the LFS procedure performed in clinical cases.

In vitro mechanical evaluation and comparison of two crimping devices for securing monofilament nylon and multifilament polyethylene for use in extracapsular stabilization of the canine stifle

OBJECTIVE

To compare the tensile strength and stiffness of non-absorbable suture loops created with two types of crimping devices.

METHODS

Loops of monofilament nylon leader line (MN) of 18 kg, 36 kg, and 45 kg multifilament polyethylene (MP) with a crimp and MP with a crimp and knot were mechanically tested to failure in quasistatic tensile loading after being created with either a wave pattern crimp device or three applications of a single crimp device. Each testing group consisted of five samples. Tensile loading to failure at a rate of 9.5 mm/s was used. Failure was defined as a sudden drop in the recorded force.

RESULTS

All suture materials failed by breaking near the crimp tube with both crimp devices, with exception of the MP without knot, which slipped through the crimp tube using both devices. Sutures secured with the wave pattern crimping device were significantly stronger with a higher load yield, maximum load, displacement yield, failure displacement, and maximum displacement than the single crimp device. Loops of MP suture crimped by either device plus the addition of a surgeon's knot resulted in a significantly stronger construct than unknotted crimped MP constructs. Crimped MP combined with knot were significantly stiffer, but not stronger, than crimped 45 kg MN.

CLINICAL SIGNIFICANCE

Performing extra- capsular repair for ruptured cranial cruciate ligaments with the wave pattern crimp system may result in lower failure rates due to the construct being significantly stronger than the single crimp system.

Comparison of three suture techniques and three suture materials on gap formation and failure load in ruptured tendons: a human cadaveric study

INTRODUCTION

There is a large variety of ruptures of tendons and ligaments in trauma surgery. Reliable data about the most appropriate suture technique and suture material for ruptured tendons are sparse. This human cadaveric study compares the biomechanical properties of three suture materials and three suture techniques for semitendinosus tendon repair.

METHOD

Sixty-three human cadaver hamstring tendons underwent tenotomy and repair with either Baseball suture, Kessler suture, or a novel "Hannover" suture, using either PDS 2-0, Ethibond 2-0, or Fiberwire 2-0. Biomechanical analysis included pretensioning the constructs with 2 N for 50 s, then cyclic loading of 500 cycles between 2 and 15 N at 1 Hz in a servohydraulic testing machine with measurement of elongation. After this, ultimate failure load and failure mode analysis was performed.

RESULTS

Ruptures repaired by Fiberwire™ as suture material and the Baseball suture technique were able to withstand significantly higher maximum failure loads (72.8 ± 22.0 N, p < 0.001) than the Kessler suture and the Hannover suture, while ruptures repaired by Fiberwire and the Kessler suture technique showed the lowest elongation after cyclic loading (14.6 ± 3.8 mm, p = 0.15).

CONCLUSION

These findings may be of relevance for the future clinical treatment of tendon ruptures. Further in vivo clinical application studies are desirable for the future.