Two-month longitudinal study of mechanical properties of absorbable sutures used in orthopedic surgery

Recent Advances in Degradable Biomedical Polymers for Prevention, Diagnosis and Treatment of Diseases

Biomedical polymers play a key role in preventing, diagnosing, and treating diseases, showcasing a wide range of applications. Their unique advantages, such as rich source, good biocompatibility, and excellent modifiability, make them ideal biomaterials for drug delivery, biomedical imaging, and tissue engineering. However, conventional biomedical polymers suffer from poor degradation in vivo, increasing the risks of bioaccumulation and potential toxicity. To address these issues, degradable biomedical polymers can serve as an alternative strategy in biomedicine. Degradable biomedical polymers can efficiently relieve bioaccumulation in vivo and effectively reduce patient burden in disease management. This review comprehensively introduces the classification and properties of biomedical polymers and the recent research progress of degradable biomedical polymers in various diseases. Through an in-depth analysis of their classification, properties, and applications, we aim to provide strong guidance for promoting basic research and clinical translation of degradable biomedical polymers.

Investigation of local stimulation effects of embedding PGLA at Zusanli (ST36) acupoint in rats based on TRPV2 and TRPV4 ion channels

Introduction

Acupoint Catgut Embedding (ACE) is an extended and developed form of traditional acupuncture that serves as a composite stimulation therapy for various diseases. However, its local stimulation effects on acupoints remain unclear. Acupuncture can activate mechanically sensitive calcium ion channels, TRPV2 and TRPV4, located on various cell membranes, promoting Ca2+ influx in acupoint tissues to exert effects. Whether ACE can form mechanical physical stimulation to regulate these channels and the related linkage effect requires validation.

Methods

This study investigates the influence of TRPV2 and TRPV4 ion channels on the local stimulation effects of ACE by embedding PGLA suture at the Zusanli (ST36) acupoint in rats and using TRPV2 and TRPV4 inhibitors. Flow cytometry, immunofluorescence, Western blot, and Real-time quantitative PCR were employed to detect intracellular Ca2+ fluorescence intensity, the expression of macrophage (Mac) CD68 and mast cell (MC) tryptase, as well as the protein and mRNA expression of TRPV2 and TRPV4 in acupoint tissues after PGLA embedding.

Results

The results indicate that ACE using PGLA suture significantly increases the mRNA and protein expression of TRPV2 and TRPV4, Ca2+ fluorescence intensity, and the expression of Mac CD68 and MC tryptase in acupoint tissues, with these effects diminishing over time. The increasing trends are reduced after using inhibitors, particularly when both inhibitors are used simultaneously. Furthermore, correlation analysis shows that embedding PGLA suture at the ST36 acupoint regulates Mac and MC functions through Ca2+ signaling involving not only TRPV2 and TRPV4 but multiple pathways.

Discussion

These results suggest that embedding PGLA suture at the ST36 acupoint generates mechanical physical stimulation and regulates TRPV2 and TRPV4 ion channels, which couple with Ca2+ signaling to form a linkage effect that gradually weakens over time. This provides new reference data for further studies on the stimulation effects and clinical promotion of ACE.

Short-Term Hydrolytic Degradation of Mechanical Properties of Absorbable Surgical Sutures: A Comparative Study

Surgical sutures play a crucial role in wound closure, facilitating the tissue-healing process across various fields of medicine. The objective of this study was to analyse the impact of seasoning time during the initial days/weeks of seasoning in Ringer's solution on the mechanical properties of five commercial absorbable sutures: SafilQuick+®, Novosyn®, MonosynQuick®, Monosyn® and Monoplus®, each with different absorption periods. The results demonstrated that the SafilQuick+ and MonosynQuick sutures lost strength within 9-12 days, as evidenced by statistically significant changes in tensile strength. In contrast, the Novosyn and Monoplus sutures did not exhibit significant changes in strength during the study period. Statistical analysis confirmed significant differences in the behaviour of the individual sutures, highlighting the importance of selecting appropriate suture material in the context of the specific medical procedure.

Biomechanical characteristics of the meniscocapsular junction of the posterior segment of the medial meniscus

PURPOSE

Despite extensive literature available on the mechanical properties of knee ligaments and menisci, research on the mechanical properties of the meniscus-capsular junction (MCJ) is lacking. This study aims to investigate the biomechanical behavior of the MCJ of the medial meniscus using a tensile failure test.

MATERIALS AND METHODS

Seven dissected cadaveric knees were used for biomechanical analysis. Tensile failure tests were performed using an INSTRON ElectroPuls E1000 stress system to measure stress/strain curves, maximum load at failure, elastic limit load, elongation at break, elongation at the elastic limit, and linear stiffness, were collected and analyzed.

RESULTS

All ruptures occurred at the MCJ. The MCJ displayed similar mechanical properties to knee ligaments. Average values were: maximum load at failure (63.9 ± 3.2 N), yield load (52.9 N ± 2.6 N), elongation at break (2.5 mm ± 0.3 mm), elongation at the elastic limit (1.25 mm ± 0.15 mm), strain at break (47.0% ± 3.5%), strain at yield (23.2% ± 2.3%), and stiffness (56.6 ± 9. N/mm-1).

CONCLUSION

The meniscus-capsular junction's mechanical properties are similar to other knee ligaments and may play a role in knee stability. The findings provide insights into the the behavior of the meniscus-capsular junction could have clinical implications for diagnosing and surgical treatment of meniscocapsular lesions.

Neuromuscular Polytrauma Pain is Resolved by Macrophage COX-2 Nanoimmunomodulation

Soft tissue injuries often involve muscle and peripheral nerves and are qualitatively distinct from single-tissue injuries. Prior research suggests that damaged innervation compromises wound healing. To test this in a traumatic injury context, we developed a novel mouse model of nerve and lower limb polytrauma, which features greater pain hypersensitivity and more sustained macrophage infiltration than either injury in isolation. We also show that macrophages are crucial mediators of pain hypersensitivity in this model by delivering macrophage-targeted nanoemulsions laden with the cyclooxygenase-2 (COX-2) inhibitor celecoxib. This treatment was more effective in males than females, and more effective when delivered 3 days post-injury than 7 days post-injury. The COX-2 inhibiting nanoemulsion drove widespread anti-inflammatory changes in cytokine expression in polytrauma-affected peripheral nerves. Our data shed new light on the modulation of inflammation by injured nerve input and demonstrate macrophage-targeted nanoimmunomodulation can produce rapid and sustained pain relief following complex injuries.

Characterizations of Capsule Closure in Hip Arthroscopy Are Infrequently and Incompletely Reported: A Systematic Review

Purpose

To review the recent literature to provide an updated characterization of capsule closure techniques in hip arthroscopy and to determine if the characteristics of closure impacted clinical outcomes.

Methods

In keeping with the Preferred Reporting in Systematic Reviews and Meta Analyses (PRISMA) guidelines, a systematic review was performed with the following eligibility criteria: patients over 18 years of age who underwent primary hip arthroscopy with reporting of patient reported outcome measures or revision/failure, and a sufficiently detailed description of capsule closure. The GRADE framework evaluated study quality, and ROBINS-I evaluated the risk of bias.

Results

Across 18 studies (N = 3277) an interportal capsulotomy was reported in 12 studies (1972/3277) cases, and a T-type capsulotomy was reported in six studies (1305/3277) cases). Six studies reported using #2 suture. Nonabsorbable suture was reported in six studies, and absorbable suture in six studies. The rate of failure was 10.5% across five studies (N = 1133) and the rate of revision was 4.4% across 13 studies (N = 2957).

Conclusions

Capsule closure is commonly performed with #2 high strength suture-the T-type using two to three sutures in the vertical limb and two to three in the transverse limb, and the interportal type using two to three sutures. Compared to earlier reports, there is a trend for increased utilization of T-type capsulotomy. Although there is a growing body of investigations into the efficacy of routine capsule closure following hip arthroscopy, our results demonstrate infrequent and inconsistent reporting of capsule closure characteristics.

Level of Evidence

Level IV, systematic review of Level I-IV studies.

Postoperative Long-Term Monitoring of Mechanical Characteristics in Reconstructed Soft Tissues Using Biocompatible, Immune-Tolerant, and Wireless Electronic Sutures

Accurate postoperative assessment of varying mechanical properties is crucial for customizing patient-specific treatments and optimizing rehabilitation strategies following Achilles tendon (AT) rupture and reconstruction surgery. This study introduces a wireless, chip-less, and immune-tolerant in vivo strain-sensing suture designed to continuously monitor mechanical stiffness variations in the reconstructed AT throughout the healing process. This innovative sensing suture integrates a standard medical suturing thread with a wireless fiber strain-sensing system, which incorporates a fiber strain sensor and a double-layered inductive coil for wireless readout. The winding design of Au nanoparticle-based fiber electrodes and a hollow core contribute to the fiber strain sensor's high sensitivity (factor of 6.2 and 15.1 pF for revised sensitivity), negligible hysteresis, and durability over 10,000 stretching cycles. To ensure biocompatibility and immune tolerance during extended in vivo periods, an antibiofouling lubricant layer was applied to the sensing suture. Using this sensing system, we successfully monitored the strain responses of the reconstructed AT in an in vivo porcine model. This facilitated the postoperative assessment of mechanical stiffness variations through a well-established analytical model during the healing period.

Biodegradable suture development-based albumin composites for tissue engineering applications

Recent advancements in the field of biomedical engineering have underscored the pivotal role of biodegradable materials in addressing the challenges associated with tissue regeneration therapies. The spectrum of biodegradable materials presently encompasses ceramics, polymers, metals, and composites, each offering distinct advantages for the replacement or repair of compromised human tissues. Despite their utility, these biomaterials are not devoid of limitations, with issues such as suboptimal tissue integration, potential cytotoxicity, and mechanical mismatch (stress shielding) emerging as significant concerns. To mitigate these drawbacks, our research collective has embarked on the development of protein-based composite materials, showcasing enhanced biodegradability and biocompatibility. This study is dedicated to the elaboration and characterization of an innovative suture fabricated from human serum albumin through an extrusion methodology. Employing a suite of analytical techniques-namely tensile testing, scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA)-we endeavored to elucidate the physicochemical attributes of the engineered suture. Additionally, the investigation extends to assessing the influence of integrating biodegradable organic modifiers on the suture's mechanical performance. Preliminary tensile testing has delineated the mechanical profile of the Filament Suture (FS), delineating tensile strengths spanning 1.3 to 9.616 MPa and elongation at break percentages ranging from 11.5 to 146.64%. These findings illuminate the mechanical versatility of the suture, hinting at its applicability across a broad spectrum of medical interventions. Subsequent analyses via SEM and TGA are anticipated to further delineate the suture's morphological features and thermal resilience, thereby enriching our comprehension of its overall performance characteristics. Moreover, the investigation delves into the ramifications of incorporating biodegradable organic constituents on the suture's mechanical integrity. Collectively, the study not only sheds light on the mechanical and thermal dynamics of a novel suture material derived from human serum albumin but also explores the prospective enhancements afforded by the amalgamation of biodegradable organic compounds, thereby broadening the horizon for future biomedical applications.

Effect of the absorption rate of suture material on oral mucosal scar formation: A triple-blind randomized controlled trial

Introduction

Extensive oral mucosal scar formation following LeFort-I osteotomy can pose patients with several scar-related complications in case of function as well as cosmesis. The present study aimed to evaluate the effect of the absorption rate of Vicryl Rapide and Vicryl on oral mucosal scar formation.

Material and methods

In a triple-blind randomized controlled trial study, Vicryl and Vicryl Rapide were used randomly for wound closure on the left and right sides of the LeFort-I incision line. Three maxillofacial surgeons evaluated mucosal scars on each side two and four months post-surgically using Mucosal Scarring Index (MSI).

Results

The differences in the total scores of MSI between the Vicryl and Vicryl Rapide groups were not significant, neither in the anterior nor in the posterior areas (Paired t-test, df = 25, CI = 95 %, P-value >0.05).

Conclusion

The results of the present study demonstrated that Vicryl Rapide is comparable to Vicryl suture material regarding the mucosal scar formation following LeFort-I osteotomy surgery; therefore, it could be considered for such oral surgical procedures.

A Novel Method to Fix Paediatric Mandibular Fracture using 2-0 Polyglactin Suture: A Technical Note

BACKGROUND

Reduction and stabilisation of fractures at the earliest is valuable in the paediatric age groups. This novel technique focuses on stabilisation of the fracture fragments using vicryl, which has an added advantage to conventional plating and wiring. This study aimed on a novel cost-effective technique of stabilising the paediatric mandibular fracture using 2-0 resorbable polyglactin 910 suture with minimal trauma to tooth buds and bone and adequate stability.

TECHNIQUE

After raising a full-thickness mucoperiosteal flap, the fracture segments are identified and reduced. 1.6mm drill bit is used to make holes through the buccal cortex on either side of the fractured segment in an anteroposterior direction. The patency of holes is checked by passing a long 26-gauge wire. The proximal end of the wire is bent into a loop, a 2-0 resorbable polyglactin suture (vicryl) is passed through this loop and the loop is pressed in place to lock the suture. The wire with the attached suture is pulled through the distal end. Once the suture is secure in place, the 26G wire is cut, and the two ends of sutures are knotted and stabilised. The mucoperiosteal flap is then closed.

CONCLUSION

A novel method of stabilisation of paediatric fracture without hampering the tooth and jaw growth, especially in the financially unstable population. 2-0 polyglactin 910 suture is cost-effective, $2 US, compared to resorbable plates costing about $150 US, and easily available. Polyglactin 910 takes 40-60 days for resorption, and half-life tensile strength is 2 weeks; thus, it gives adequate stability and time for callus formation and does not damage the tooth buds or bone by cutting through them.

The effect of medical grade honey on tensile strength, strain, and Young's modulus of synthetic absorbable suture material used in equine surgery

BACKGROUND

Medical grade honey (MGH) has been introduced as a protective measure against surgical site infections in equine surgery, but the effect on suture material has not been investigated.

OBJECTIVE

To evaluate the effect of MGH on the tensile properties of three synthetic absorbable suture materials.

STUDY DESIGN

In vitro experiments.

METHODS

Ten strands of Polydioxanone USP 2 (PD2), Polyglactin 910 USP 2 (PG2) and Polyglecaprone USP 2-0 (PC2-0) were incubated 1, 7, 14, 21 and 28 days in MGH, phosphate-buffered saline (PBS), equine plasma (EP) and MGH mixed with equine plasma (HP). Mechanical testing was performed recording maximum load at failure (N), strain at failure and Young's modulus (N/mm2 ). The results were reported from a Welch or regular ANOVA.

RESULTS

PD2 in MGH had a significantly higher tensile strength compared to PD2 in EP (p < 0.05, mean difference (md) = 16.95 N, CI95% (9.19-24.70 N)) and PBS (p < 0.05, md = 14.48 N CI95% (6.73-22.23 N)) on day 7 and the remaining time points. PG2 incubated in MGH had a significantly higher tensile strength compared to EP (p < 0.05, md = 69.28 N CI95% (64.16-74.40 N)) and PBS (p < 0.05, md = 56.90 N CI95% (51.78-62.02 N)) until day 28. PC2-0 incubated in MGH had a significantly higher tensile strength compared to EP (p < 0.05 md = 12.40 N CI95% (4.59 N-20.20 N)) and PBS (p < 0.05 md = 11.23 CI95% (3.42-19.03 N)) on day 7 and the remaining time points.

MAIN LIMITATIONS

The sutures were unloaded during incubation and a single cycle to failure test was only performed, which does not reflect the in vivo environment where shear forces are present.

CONCLUSIONS

MGH did not negatively affect the tensile strength of the suture material and can safely be applied in contact with suture materials commonly used in equine surgery.

Transdermal wires for improved integration in vivo

Alternative engineering approaches have led the design of implants with controlled physical features to minimize adverse effects in biological tissues. Similar efforts have focused on optimizing the design features of percutaneous VAD drivelines with the aim to prevent infection, omitting however a thorough look on the implant-skin interactions that govern local tissue reactions. Here, we utilized an integrated approach for the biophysical modification of transdermal implants and their evaluation by chronic sheep implantation in comparison to the standard of care VAD drivelines. We developed a novel method for the transfer of breath topographical features on thin wires with modular size. We examined the impact of implant's diameter, surface topography, and chemistry on macroscopic, histological, and physical markers of inflammation, fibrosis, and mechanical adhesion. All implants demonstrated infection-free performance. The fibrotic response was enhanced by the increasing diameter of implants but not influenced by their surface properties. The implants of small diameter promoted mild inflammatory responses with improved mechanical adhesion and restricted epidermal downgrowth, in both silicone and polyurethane coated transdermal wires. On the contrary, the VAD drivelines with larger diameter triggered severe inflammatory reactions with frequent epidermal downgrowth. We validated these effects by quantifying the infiltration of macrophages and the level of vascularization in the fibrotic zone, highlighting the critical role of size reduction for the benign integration of transdermal implants with skin. This insight on how the biophysical properties of implants impact local tissue reactions could enable new solutions on the transdermal transmission of power, signal, and mass in a broad range of medical devices.

Knot strength and antimicrobial evaluations of partially absorbable suture

Partially absorbable suture is useful for orthopedic repair as it possesses the capacity to promote a balance between strength, degradation rate and minimal inflammation. Still, the availability of partially absorbable suture is scarce. So far, no study has examined the mechanical strength and anti-microbial properties of partially absorbable monofilament suture made of low-density polyethylene (LDPE)/polylactide (PLA)/chitosan (CHS); hence, the reason for this study with a view to improve knot strength, antimicrobial property and degradation rate. In this study, monofilament suture was extruded using different weight fractions of LDPE, PLA and CHS. In vitro degradation studies were carried out using phosphate buffer solution (PBS). Mechanical and morphological changes were also examined. A standard Fourier transform infrared spectral of 3433, 2909-2840, 1738, 1452, 1174, 1062, 706 cm^-1 were assigned to OH group, C-H stretch, C=O vibration of ester, CH₃ bending, alkyl ester and CH₂ stretch, respectively. Tensile strength of knotted neat LDPE (4.84 MPa) exhibited 48.7% improvement in LDPE/PLA/CHS (60/39.5/0.5). This suggests that a good knot can be achieved to 40% weight fraction of PLA. The monofilament suture also demonstrated better antimicrobial property as the monofilament, LDPE/PLA/CHS (60/39.5/0.5) and LDPE/PLA/CHS (50/49.5/0.5) covered 12.7 mm zone of inhibition which is greater than the standard 1 mm. The suture's morphological phases show dark fibre-like rough surfaces with microstructural irregularities as PLA and CHS were added to the matrix, which is required for enhanced degradation. Thus, the partially absorbable suture produced in this study could serve as a suture for tendon repair.

Absorbable suture for band tightening of scleral buckling in pseudophakic rhegmatogenous retinal detachment: a modified surgical technique and a 6-month follow-up

Background

Rhegmatogenous retinal detachment (RRD) is a separation of the neurosensory retina from the retinal pigment epithelium as a result of liquid vitreous passing through a retinal break. Scleral buckling surgery (SB) is a conventional treatment for RRD. In SB, a silicon explant is used to indent the sclera, reduce vitreous traction, and close the retinal break, and an encircling band is used circumferentially, leading to myopia. This study aimed to evaluate the functional and biometric outcomes after SB with absorbable band-tightening sutures in patients with pseudophakic RRD.

Methods

In this prospective interventional study, we included pseudophakic eyes with RRD treated surgically with SB and a temporary encircling band using a 6-0 absorbable Vicryl suture to tighten the band, instead of conventional permanent suture tightening. Anterior chamber depth (ACD), axial length (AL), intraocular pressure (IOP), spherical equivalent refractive error (SER), and best-corrected distance visual acuity (BCDVA) were measured preoperatively and at 1 day, 2 weeks, 3 months, and 6 months postoperatively.

Results

We included 30 eyes of 30 patients with a mean (standard deviation [SD]) age of 66.1 (10.5) years who underwent SB with an absorbable band-tightening suture for pseudophakic RRD. Significant increases in AL and ACD were observed at 2 weeks after surgery, with a significant decline in values thereafter; however, at the 6-month follow-up, the values were significantly higher than those at baseline (all P < 0.05). Based on the Vicryl tension and its hydrolysis, mean (SD) SER at 2 weeks postoperatively was significantly more myopic than at baseline (-5.8 [1.6] D versus +1.3 [1.8] D). However, the mean (SD) SER decreased significantly throughout the 6-month follow-up (all P < 0.05), and it reached -1.8 (0.9) D, which was comparable with the mean baseline SER (P = 0.140). The participants experienced significant improvement in BCDVA throughout the follow-up period (all P < 0.05).

Conclusions

Using an absorbable suture to tighten the encircling band in patients with pseudophakic RRD can reduce postoperative myopia without adversely affecting the anatomical or functional outcomes. Future comparative studies with larger sample sizes and longer postoperative follow-up are needed to verify these findings.

Variability in wound closure technique in midline posterior lumbar fusion surgery. International survey and standardized closure technique proposal

Background:

Surgical wound complications represent an important risk factor, particularly in multilevel lumbar fusions. However, the literature regarding optimal wound closure techniques for these procedures is limited.

Methods:

We performed an online survey of 61 spinal surgeons from 11 countries, involving 25 different hospitals. The study included 26 neurosurgeons, 21 orthopedists, and 14 residents (Neurosurgery – 6 and orthopedics 8). The survey contained 17 questions on demographic information, closure techniques, and the use of drainage in posterior lumbar fusion surgery. We then developed a “consensus technique.”

Results:

The proposed standardized closure techniques included: (1) using subfascial gravity drainage (i.e., without suction) with drain removal for <50 ml/day or a maximum duration of 48 h, (2) paraspinal muscle, fascia, and supraspinous ligament closure using interrupted-X stitches 0 or 1 Vicryl or other longer-lasting resorbable suture (i.e., polydioxanone suture), (3) closure of subcutaneous tissue with interrupted inverted Vicryl 2-0 sutures in two planes for subcutaneous tissue greater >25 mm in depth, and (4) skin closure with simple interrupted nylon 3-0 sutures.

Conclusion:

There is great variability between closure techniques utilized for multilevel posterior lumbar fusion surgery. Here, we have described various standardized/evidence-based proven techniques for the closure of these wounds.

Absorbable versus nonabsorbable sutures for the Krackow suture repair of acute Achilles tendon rupture: a prospective randomized controlled trial

AIMS

Although absorbable sutures for the repair of acute Achilles tendon rupture (ATR) have been attracting attention, the rationale for their use remains insufficient. This study prospectively compared the outcomes of absorbable and nonabsorbable sutures for the repair of acute ATR.

METHODS

A total of 40 patients were randomly assigned to either braided absorbable polyglactin suture or braided nonabsorbable polyethylene terephthalate suture groups. ATR was then repaired using the Krackow suture method. At three and six months after surgery, the isokinetic muscle strength of ankle plantar flexion was measured using a computer-based Cybex dynamometer. At six and 12 months after surgery, patient-reported outcomes were measured using the Achilles tendon Total Rupture Score (ATRS), visual analogue scale for pain (VAS pain), and EuroQoL five-dimension health questionnaire (EQ-5D).

RESULTS

Overall, 37 patients completed 12 months of follow-up. No difference was observed between the two groups in terms of isokinetic plantar flexion strength, ATRS, VAS pain, or EQ-5D. No re-rupture was observed in either group.

CONCLUSION

The use of absorbable sutures for the repair of acute ATR was not inferior to that of nonabsorbable sutures. This finding suggests that absorbable sutures can be considered for the repair of acute ATRs. Cite this article: Bone Joint J 2022;104-B(8):938-945.

Suture Materials, Needles, and Methods of Skin Closure: What Every Hand Surgeon Should Know

Sutures are used ubiquitously in surgery and are the most implanted materials in hand surgery. However, surgical training does not routinely include formal education on stitching materials or needles. Rather, suture familiarity is passed down by common use throughout training. We focus on a brief history and evolution of suture materials and suture needles, their material and mechanical properties, hand surgery-specific applications, other methods of skin closure (staples, skin glue, and adhesive strips), a cost analysis, and advances in musculoskeletal suturing, with a look toward the future. Equipped with a fundamental knowledge of suture needles and suture materials, hand surgeons will be better prepared to select the most appropriate, situation-specific tools.

Development of an Antimicrobial-Coated Absorbable Monofilament Suture from a Medical-Grade Poly(l-lactide-co-ε-caprolactone) Copolymer

In this study, a medical-grade poly(l-lactide-co-ε-caprolactone) (PLC) copolymer with a monomer ratio of l-lactide (L) to ε-caprolactone (C) of 70:30 mol % for use as an absorbable surgical suture was synthesized via ring-opening polymerization (ROP) using a novel soluble liquid tin(II) n-butoxide (Sn(OnC4H9)2) as an initiator. In fiber fabrication, the process included copolymer melt extrusion with a minimal draw followed by sequential controlled hot-drawing and fixed-annealing steps to obtain oriented semicrystalline fibers with improved mechanical strength. For healing enhancement, the fiber was dip-coated with "levofloxacin" by adding the drug into a solution mixture of acetone, poly(ε-caprolactone) (PCL), and calcium stearate (CaSt) in the ratio of acetone/PCL/CaSt = 100:1% w/v:0.1% w/v. The tensile strength of the coated fiber was found to be increased to ∼400 MPa, which is comparable with that of commercial polydioxanone (PDS II) of a similar size. Finally, the efficiency of the drug-coated fiber regarding its controlled drug release and antimicrobial activity was investigated, and the results showed that the coated fiber was able to release the drug continuously for as long as 30 days. For fiber antimicrobial activity, it was found that a concentration of 1 mg/mL was sufficient to inhibit the growth of Staphylococcus aureus (MRSA), Escherichia coli O157:H7, and Pseudomonas aeruginosa, giving a clear inhibition zone range of 20-24 mm for 90 days. Cytotoxicity testing of the drug-coated fibers showed a %viability of more than 70%, indicating that they were nontoxic.

Evaluation of canine adipose-derived multipotent stromal cell differentiation to ligamentoblasts on tensioned collagen type I templates in a custom bioreactor culture system

OBJECTIVE

To evaluate differentiation of canine adipose-derived multipotent stromal cells (ASCs) into ligamentoblasts on tensioned collagen type I (Col1) templates in a perfusion culture system.

SAMPLES

Infrapatellar fat pad ASCs from healthy stifle joints of 6 female mixed-breed dogs.

PROCEDURES

Third-passage ASCs (6 × 10⁶ cells/template) were loaded onto suture-augmented Col1 templates under 15% static strain in perfusion bioreactors. Forty-eight ASC-Col1 constructs were incubated with ligamentogenic (ligamentogenic constructs; n = 24) or stromal medium (stromal constructs; 24) for up to 21 days. Specimens were collected from each construct after 2 hours (day 0) and 7, 14, and 21 days of culture. Cell number, viability, distribution, and morphology; construct collagen content; culture medium procollagen-I-N-terminal peptide concentration; and gene expression were compared between ligamentogenic and stromal constructs.

RESULTS

ASCs adhered to collagen fibers. Cell numbers increased from days 0 to 7 and days 14 to 21 for both construct types. Relative to stromal constructs, cell morphology and extracellular matrix were more mature and collagen content on day 21 and procollagen-I-N-terminal peptide concentration on days 7 and 21 were greater for ligamentogenic constructs. Ligamentogenic constructs had increased expression of the genes biglycan on day 7, decorin throughout the culture period, and Col1, tenomodulin, fibronectin, and tenascin-c on day 21; expression of Col1, tenomodulin, and tenascin-c increased between days 7 and 21.

CONCLUSIONS AND CLINICAL RELEVANCE

Ligamentogenic medium was superior to stromal medium for differentiation of ASCs to ligamentoblasts on suture-augmented Col1 scaffolds. Customized ligament neotissue may augment treatment options for dogs with cranial cruciate ligament rupture.

Suture osteosynthesis in the bony reconstruction of thumb duplication

Metacarpal osteotomies are done to correct deviation deformity in thumb duplication. We describe a suture-only technique of metacarpal osteosynthesis, without using K-wires. Thirteen Flatt Type IV thumbs and five Wassel Type VII thumbs were reconstructed with this technique. The median follow-up was 23 months. After osteotomy, the metacarpal bone fragments were sutured together with 5-0 polyglactin or 4-0 polydioxanone sutures. Metacarpal fragment displacement was not observed on postoperative radiographs obtained at 1 and 2 weeks. Bony union was achieved at 6 weeks without loss of alignment. The metacarpophalangeal joint alignment was anatomical (≤5° deviation) in eight cases. The mean pre- and postoperative metacarpophalangeal joint alignments were 27° and 9°, respectively. The 11 patients who were available for grading with the Japanese Society for Surgery of the Hand Score were assessed as good. Complete internalization of the bony fixation eliminates infections associated with exposed K-wires without compromising the overall outcome.Level of evidence: IV.

In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses

A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young's modulus (E) and tensile strength at break (σ_b ) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

Application of Polydioxanone Sutures in the Nuss Procedure

BACKGROUND/PURPOSE

 The Nuss procedure is the most common surgical repair for pectus excavatum (PE). Surgical steel wires are used in some modifications of the Nuss procedure to attach one or both ends of a support bar to the ribs. During follow-up, wire breakage was found in some cases. Patients with wire breakage may undergo prolonged bar removal surgery and may be exposed to excessive radiation.In this study, we had a series of patients who received polydioxanone suture (PDS) fixations instead of steel wires. This retrospective study was conducted to explore the differences between these two fixation materials in the incidence of related complications and efficacies. Furthermore, we attempted to observe whether the two materials lead to similar surgical efficacy in the Nuss procedure, whether they have divergent effects on the bar removal surgery, and whether PDS can reduce the risks due to steel wire breakage as expected.

METHODS

 We retrospectively studied PDS and surgical steel wires as fixation materials for the Nuss procedure in children with congenital PE and reviewed the outcomes and complications. A total of 75 children who had undergone Nuss procedure repairs and bar removals from January 2013 to December 2019 were recruited to participate in this study. They were divided into three groups: the PDS group, the unbroken wire (UBW) group, and the broken wire (BW) group, according to the fixation materials and whether the wires had broken or not. Moreover, we selected the duration of operation (DO), intraoperative blood loss (BL), bar displacement (BD), postoperative pain score (PPS), and incision infection as the risk indicators and the postrepair Haller index (HI) as the effectiveness indicator. These indicators were statistically compared to determine whether there were differences among the three groups.

RESULTS

 One BD occurred in the PDS and BW groups while none took place in the UBW group. No incision infection was found in any of the groups. The PDS group had the shortest DO, while the DO in the UBW group was shorter than that in the BW group (p < 0.05). BL in the PDS group was less than that in the other two groups (p < 0.05). Additionally, no difference was observed in BL between the BW and UBW groups (p > 0.05). The PPS of the PDS group was less than that of the BW group (p < 0.05), whereas no differences were found between the other two groups. No statistical difference emerged in HI among the groups (p > 0.05).

CONCLUSION

 PDS fixation results in a similar repair outcome and shows certain advantages in the DO, BL, and PPS; also, PDSs are safe and effective in the Nuss procedure.

LEVEL OF EVIDENCE

 Level III.

Postoperative Failure Frequency of Short External Rotator and Posterior Capsule With Successful Reinsertion After Primary Total Hip Arthroplasty: An Ultrasound Assessment

BACKGROUND

The reinsertion of the short external rotators and posterior capsule to the greater trochanter in the posterolateral approach has been considered an effective strategy to reduce the risk of dislocation. However, during clinical practice, no verification and monitoring of the status of such reinsertions is carried out. The objective of this study is to estimate the frequency of postoperative failure with successful reinsertion of the short external rotator and posterior capsule of the hip through ultrasound after primary total hip arthroplasty (THA) using the posterolateral approach.

METHODS

A prospective observational study was conducted involving patients with primary total hip arthroplasty via posterolateral approach in which reinsertion of hip's short external rotators and posterior capsule were successful reinserted during surgery from January to December 2019. The status of the reinsertion was assessed with an ultrasound between the 6 and 8 weeks after surgery. Reinsertion failure was considered when the reinserted structures were not fully visualized in the ultrasound during internal and external rotation.

RESULTS

Sixty-eight patients were included in this study (mean age: 58.7 ± 13.8 years; 44.1% (30) women). The incidence of failure of the reinsertion of short external rotators and posterior capsule was 16.2% (n = 11) (95% confidence interval 9.3-26.7). A postoperative increased femoral offset was found more frequently in cases with failure (36.4% vs 17.5%); a similar trend was observed in the leg length discrepancy (36.4% vs 22.8%). However, these differences were not statistically significant (P > .05).

CONCLUSION

Between the 6th and 8th postoperative week, approximately 2 of the 10 short external rotator and posterior capsule reinsertions fail in cases with successful intraoperative repair using absorbable suture. This estimate is comparable and even lower than previous reports.

EVIDENCE LEVEL

II, Prospective Observational Study.

In vitro holding security of four friction knots of monofilament or multifilament suture used as a first throw for vascular ligation

OBJECTIVE

To evaluate holding security of 4 friction knots created with various monofilament and multifilament sutures in a vascular ligation model.

SAMPLE

280 friction knot constructs.

PROCEDURES

10 friction knots of 4 types (surgeon's throw, Miller knot, Ashley modification of the Miller knot, and strangle knot) created with 2-0 monofilament (polyglyconate, polydioxanone, poliglecaprone-25, and glycomer-631) and braided multifilament (silk, lactomer, and polyglactin-910) sutures were separately tied on a mock pedicle and pressure tested to the point of leakage. Linear regression analysis was performed to compare leakage pressures among suture materials (within friction knot type) and among knot types (within suture material).

RESULTS

Mean leakage pressure of surgeon's throws was significantly lower than that of all other knots tested, regardless of the suture material used. All the other knots had mean leakage pressures considered supraphysiological. Significant differences in mean leakage pressure were detected between various friction knots tied with the same type of suture and various suture types used to create a given knot. Variability in leakage pressure among knots other than the surgeon's throw was greatest for poliglecaprone-25 and lowest for polydioxanone.

CONCLUSIONS AND CLINICAL RELEVANCE

Most differences in knot security, although statistically significant, may not have been clinically relevant. However, results of these in vitro tests suggested the surgeon's throw should be avoided as a first throw for pedicle ligation and that poliglecaprone-25 may be more prone to friction knot slippage than the other suture materials evaluated.

Does skin preparation alter suture strength characteristics? Assessing the effect of chlorhexidine and isopropyl alcohol on common skin closure suture material

Sutures are essential to approximate tissues and enable healing by first intention until a wound regains its original tensile strength. The mechanical properties of sutures are well documented, but the effects of exposing sutures to skin preparation solutions used in surgery are not. This study was performed to investigate whether 2% chlorhexidine and 70% isopropyl alcohol skin preparation, commonly used prior to incision and prior to closure, has any effect on the mechanical properties of several commonly used surgical suture types. Four suture types were soaked in either 2% chlorhexidine and 70% isopropyl alcohol or Hartmann's solution for 5 minutes. All sutures were left to dry for 11 days before being tested to failure using an Instron 3367 tensile testing machine. Testing revealed significant differences in failure load, ultimate tensile stress, and Young's modulus between suture types (P < .05). No significant differences in failure load (P = .98), ultimate tensile stress (P = .21), or Young's modulus (P = .22) were observed between the test group and the control group when comparing sutures of the same type. This study demonstrates that chlorhexidine/isopropyl skin preparation solutions do not significantly change the mechanical properties of suture materials exposed to them.

Effect of Biological Environment on Polyester Surgical Suture's Physical Properties: An Experimental Study in Rats

Objective

The following study aims to analyze the alteration of nonabsorbable polyester surgical suture physical properties after in vivo incubation.

Methods

A comparative study of braided nonabsorbable polyester 2/0 (U.S.P) sutures was performed. The control in vitro group and three experimental in vivo subgroups, composed of ten sutures in each, were created. All 30 experimental sutures were implanted into a total of 15 laboratory rats subcutaneous tissue (two sutures in each rat) and removed after seven, eight and nine weeks, respectively. Further, they were attached to the mechanical testing device and affected with a mechanical force, increasing the load by 0,1 N/s until complete breakage. Tensile strength (TS), failure displacement (FD), failure strain (FS) and failure stress (FST) were measured at the point of failure and compared to the same parameters of the control group.

Results

No statistically significant difference was found in the physical parameters of the samples between the experimental and control groups (TS [p = 0.358], FD [p = 0.258], FS [p = 0.258] FST [p = 0.358]). A statistically significant difference was found in the failure load between sutures that break on the knot site (KS) and the rest of the samples: significantly less force was needed to break the suture on the KS. Moreover, most of the breaks on the KS occurred in sutures that were incubated for the longest period of nine weeks (n = 4). An anomaly of partial failure (PF) was noticed. Sutures with PF elongated significantly more compared to the sutures that did not undergo PF in the control and in experimental groups (p = 0,044; p = 0,017; p = 0,016; p = 0,013).

Conclusion

The biological environment had no radical aftereffects to the suture’s physical properties. In vivo exposure may cause the suture to break on the KS more frequently and may lead to PF, when a few sutures composed of fiber fail. Sutures that undergo PF tend to elongate further.

Tensile properties of synthetic, absorbable monofilament suture materials before and after incubation in phosphate-buffered saline

OBJECTIVE

To compare tensile properties of synthetic, absorbable, monofilament suture material before and after incubation in phosphate-buffered saline (PBS).

STUDY DESIGN

Two sizes (2-0 and 3-0) of Biosyn, Maxon, Monocryl, PDS II, Securocryl, and Securodox were tested.

SAMPLE POPULATION

Ten suture loops per group.

METHODS

Tensile strength, elongation, and modulus of suture loops were measured at baseline and after 7, 14, 21, or 28 days of incubation in PBS.

RESULTS

Size, suture material, and size × suture material interaction influenced maximum breaking load, maximum elongation, and modulus of elasticity. At baseline, 2-0 and 3-0 Maxon had the highest breaking loads (111.67 N and 79.71 N, respectively) for their size, and 2-0 PDSII and 3-0 Securodox had the lowest (68.71 N and 48.73 N, respectively). Maxon 2-0 and 3-0 had the greatest elongations (9.68 mm and 8.45 mm, respectively) for their size, and 2-0 Biosyn and 3-0 Securocryl had the least (7.21 mm and 6.58 mm, respectively). Biosyn 2-0 and 3-0 had the highest modulus. With incubation, Maxon (2-0), PDS II (2-0, 3-0), and Securodox (2-0, 3-0) maintained or gained strength over 4 weeks. Strengths of 2-0 and 3-0 Biosyn and 3-0 Maxon were maintained for 2 weeks, while Monocryl and Securocryl lost 20% to 44% of baseline strength within 1 week and 60% to 72% within 2 weeks. Day 7 strengths of 2-0 Biosyn and 2-0 Monocryl were greater than baseline strength of 2-0 PDS II. Strength of 3-0 Biosyn at day 14 was greater than strength of Monocryl at days 7 and 14 and greater than strength of 3-0 PDS II, 3-0 Securodox, and 3-0 Securocryl at baseline and days 7 and 14.

CONCLUSION

Suture tensile properties varied with suture size, composition, and brand. At baseline, Maxon suture had the greatest strength and elongation, and Biosyn had the greatest stiffness.

CLINICAL SIGNIFICANCE

Tensile strength retention, when reported as a percentage of original strength, provides insufficient information for comparison of suture tensile properties.

Mechanical properties of Triclosan sutures

To avoid infections and wound healing disorders, Triclosan coated sutures have been invented. Little is known of these sutures regarding their tensile properties. Three different Triclosan coated sutures (Vicryl 1 plus, PDS 0 plus, Monocryl 3-0 plus) were tested at several time points over 42 days regarding load to failure, strain, and stiffness compared to their non-coated versions (Vicryl 1, PDS 0, Monocryl 3-0). Four different measurement points were made. Suture loops were fixed in a material testing machine over two metal bars which were moved apart creating a stress to the fiber. Unpaired, two-tailed t-test were performed for each group (untreated and treated) while level of significance was defined at a level of p < 0.05. Vicryl 1 was significantly stronger on day 14 than Vicryl 1 plus (p = 0.033). On day 28, significant changes were found in PDS 0 which was weaker compared to PDS 0 plus (p = 0.039) and Vicryl 1 which was stronger than Vicryl 1 plus (p = 0.032). We have seen that Vicryl 1 plus sutures are significantly weaker according to loading to failure after 14 and 28 days, which might cause incisional hernias. PDS 0 sutures are used to reconstruct tendons, therefore a longer durableness might be of interest as re-ruptures of tendons are problematic. Our in vitro findings support, the use of Triclosan coated PDS plus sutures and Vicryl sutures as they show a longer resistance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1777-1782, 2018.

Comparison of two surgical suture techniques in uvulopalatopharyngoplasty and expansion sphincter pharyngoplasty

BACKGROUND

Uvulopalatopharyngoplasty (UPPP) and expansion sphincter pharyngoplasty (ESP) are two standard surgical procedures for treatment of snoring and sleep apnea. In a prospective clinical trial, we compared a standard simple interrupted suture technique for closure of the tonsillar pillars with a running locked suture.

METHODS

Each suture technique was randomly assigned either to the left or the right tonsillar pillars in 28 patients. During the first week, patients were daily checked for suture dehiscence and again on days 10 and 21, the end of followup. Time to perform the sutures was measured intraoperative and surgical complications were recorded.

RESULTS

During followup, suture dehiscence was observed in 15/28 interrupted and 16/28 running sutures (p > 0.5). If a dehiscence occurred during the observation period, the median day of dehiscence was 10 (1 and 3 quartile: 5.75 and 17) days for the interrupted suture and 10 (5-11) days for the running locked suture technique (p > 0.05). The mean (± SD) surgical time for the interrupted suture was 5.2 ± 1.9 and 3.5 ± 1.8 min for the running locked suture (p < 0.001). Postoperative bleedings occurred in 4/28 running sutures and 2/28 interrupted sutures.

CONCLUSION

The running locked suture technique is an equally safe and time saving way of wound closure in UPPP and ESP.