Repair Construct Research Articles

Development of Modular, Dual-Perfused Osteochondral Constructs for Cartilage Repair.

This study describes methods for fabricating, culturing, and characterizing modular microbeads containing progenitor cells that can be used to create osteochondral tissue constructs. Such biphasic engineered tissues were cultured in a low flow rate perfusion bioreactor chamber to maintain tissue-specific differentiation while allowing development of the osteochondral interface.

OUTCOMES OF DISCOID MENISCUS REPAIRS IN CHILDREN AND ADOLESCENTS

Background: Discoid meniscus tear patterns vary, but typically involve horizontal cleavage tears of the central discoid component with or without anterior or posterior meniscocapsular tears. Classically, the central discoid component is saucerized and meniscocapsular tears are repaired. Recent data suggests that meniscal preservation provides long-term benefits over resection1-2. However, many meniscal transplants are performed secondary to unsalvaged or unsalvageable discoid meniscus tears3. Reoperation rates after meniscus repairs vary greatly4-6, with some series reporting high rates of reinjury and reoperation, but there are no large series of pediatric discoid meniscus repairs in the literature. The purpose of this study is to describe the outcomes of meniscus repair and saucerization in pediatric patients with symptomatic discoid menisci. Methods: A single-institution retrospective review was performed of consecutive pediatric patients with surgical treatment of a discoid meniscus tear over a five-year period. Inclusion criteria were age less than 18 years, a symptomatic torn discoid meniscus treated with knee arthroscopy with meniscus repair, and minimum 4-month follow-up. A chart review was performed to describe tear location, tear pattern, and repair type (inside-out, outside-in, all-inside, and hybrid). Hybrid repair constructs were defined as those that used 2 or more repair types. The primary outcome was revision meniscus surgery. Results: Forty-four patients were identified to meet inclusion criteria. There were 23 males and 21 females with a mean age of 12.4 years (range 5 – 17 years). The right knee was affected in 61% of patients. The lateral meniscus was involved in all patients. Tear patterns included anterior meniscocapsular (19 patients, 43%), posterior meniscocapsular (14 patients, 30%), radial (7 patients, 16%), and bucket-handle (5 patients, 11%). Tears most commonly involved the posterior horn and body (21 patients, 48%) or posterior horn (16 patients, 36%) Arthroscopic meniscus repair was performed in all patients. Forty-three patients (98%) also underwent saucerization. Marrow stimulation, as a biological approach to improve repair healing, was performed in 14 patients (32%). The distribution of repair types and number of sutures for each type is listed in the table below. Mean follow-up was 19 months (range 4 – 70 months). Four patients (9%) underwent revision meniscus surgery following the primary repair, including 2 all-inside repairs and 2 partial meniscectomies. There were no statistically significant differences between patients who did or did not require a secondary surgery with respect to sex, age, tear location, tear pattern, repair type, or number of sutures. During follow-up, 9 patients (20%) had surgery for a symptomatic discoid meniscus in the contralateral knee. Conclusions: Saucerization and repair of discoid lateral meniscus tears in the pediatric population have good outcomes with low rates of reoperation. Appropriate saucerization, followed by an arthroscopic assessment of stability and tear patterns is critical to successful treatment of symptomatic discoid menisci. If tissue quality permits, meniscal preservation should be considered in all patients to avoid the consequences of subtotal meniscectomy. [Table: see text] Manzione M, Pizzutillo PD, Peoples AB, et al. Meniscectomy in children: a long-term follow-up study. Am J Sports Med 1983;11:111-115. Ahn JH, Kim KI, Wang JH, et al. Long-term results of arthroscopic reshaping for symptomatic discoid lateral meniscus in children. Arthroscopy 2015;31(5):867-873. Kocher MS, Tepolt FA, Vavken P. Meniscus transplantation in skeletally immature patients. J Pediatr Orthop B 2016;25(4)343-348. Steadman JR, Matheny LM, Singleton SB, et al. Meniscus suture repair: minimum 10-year outcomes in patients younger than 40 years compared with patients 40 and older. Am J Sports Med 2015;43(9):2222-2227. Paxton ES, Stock MV, Brophy RH. Meniscal repair versus partial meniscectomy: a systematic review comparing reoperation rates and clinical outcomes. Arthroscopy 2011;27(9):1275-1288. Shieh AK, Edmonds EW, Pennock AT. Revision meniscal surgery in children and adolescents: risk factors and mechanisms for failure and subsequent management. Am J Sports Med 2016;44(4):838-843.

Arthroscopic Rotator Cuff Repair: How to Avoid Retear

A healed rotator cuff repair results in a superior outcome for the patient compared with a non-healed repair. The surgeon can maximize the chance of a healed repair by knowing the end-point of each key step in the repair process and adhering to a few core principles. First, the rotator cuff tear pattern (e.g. crescent, L-tear, reverse L-tear, U-tear) must be recognized, starting with careful assessment of preoperative MRI but concluding with the arthroscopic assessment of tear edge mobility. Second, a low-tension, anatomic, and mechanically robust repair construct (e.g. linked, double row; load-sharing rip stop; margin convergence to bone) must be determined based on the tear pattern. Increasingly, surgeons are recognizing the importance of the superior capsule of the shoulder, which can appear as a separate pathoanatomic structure in a delaminated rotator cuff tear and require independent suturing in the repair construct. Third, the biological healing capacity of the repair site must be optimized by using meticulous preparation of the greater tuberosity bone, including removal of soft tissue remnants, light burring, and creation of bone vents. Finally, avoid aggressive early rehabilitation after arthroscopic rotator cuff repair respecting that tendon to bone healing is unlikely to occur before 12 weeks postoperatively. Sling immobilization and judicious use of early passive motion should be used for the first 6 weeks, with passive shoulder range of motion performed during weeks 6-12 postoperatively. Rotator cuff strengthening, and active overhead use of the arm should be delayed until at least 12 weeks after surgery to minimize the risk of retear.

ОЦЕНКА ТОЧНОСТИ ПОСТАНОВКИ ПУТИ В ПРОЕКТНОЕ ПОЛОЖЕНИЕ С ИСПОЛЬЗОВАНИЕМ САУ-3D

The article deals with the problem of setting the railway track in the design position. Identi-fied shortcomings of existing systems of automated management of construction machinery. The technology of setting the path in the design position of the automated control systems based on global navigation satellite systems, the technical implementation of the system.Presents the problem of the use of technologies based on geoinformation system in creating repair projects, construction (repairs) and operational work, particularly the lack of electronic projects for the automated control systems based on global navigation satellite systems. Is a principle of updating project data, namely the geometrical parameters, before the production of works and the creation of electronic projects. Considered part of the electronic project for ACS-3D straightening techniques. The evaluation of the accuracy of staging the way to the design position of the geometric parameters and compares the results with the requirements of regulatory documents.

Risk of the building deformation because of above-permitted standard subsidence

The authors suppose that the vulnerability of natural-and-technical system in relation to the subsidence can be equated to the financial costs of repair or new construction with the summation of losses from the temporary exception of this system from the economic activity. Then the vulnerability can be considered as the economic damage, and risk can be considered as the multiplication of damage by the probability of a dangerous event. The method of calculation of geological risk is offered in the article and can be applied in practice by geologists, mathematicians and designers.

Performance Research on Rapid Repair Materials of Composite Cementitious Materials

In order to repair construction rapidly, according to the different proportion, ordinary Portland cement and sulphur alumínate cement(SAC) are used to make up composite cementitious materials, the setting time, strength and deformation of composite system are researched to satisfy the special requirement of fast repair. Test results show that composite cementitious materials have superior performance in various aspects when the SAC is 15%, on the basis of this benchmark ratio mixed with proper amount of polypropylene fiber, high efficiency water reducing agent and mineral admixtures, composite cementitious mortar can be made out with a short setting time, good workability and high strength.

管板桩油码头水下修补施工技术应用

管板桩油码头水下修补施工技术应用

Large Scale Repair Construction at the Coal-fired Power Pier Superstructure in Okinawa

Large Scale Repair Construction at the Coal-fired Power Pier Superstructure in Okinawa

Three-dimensional bioprinting for organ bioengineering: promise and pitfalls.

Loss of organ function is a critical issue that threatens a patient's life. Currently, the only available treatment is organ transplantation; however, shortage of donor organs, histocompatibility, and life-long immunosuppression present major challenges. Three-dimensional bioprinting technology holds a promising solution for treating organ failure by fabricating autologous tissues and organs for transplantation. To biofabricate a functional tissue, target-cell types are combined with an appropriate biomaterial for structural support and a bioink that supports cell function and maturation. Bioprinted structures can mimic the native tissue shape and functionality. The main goal of three-dimensional bioprinting is to produce functional tissues/organs; however, whole organ printing has not been achieved. There have been recent advances in the successful three-dimensional bioprinting of numerous tissues. This review will discuss the types of bioprinters, biomaterials, bioinks, and the fabrication of various constructs for repair of vascular, cartilage, skin, cardiac, and liver tissues. These bioprinted tissue constructs have the potential to be used to treat tissues and organs that have been damaged by injury or disease. Three-dimensional bioprinting technology offers the ability to fabricate three-dimensional tissue structures with high precision, fidelity, and stability at human clinical scale. The creation of complex tissue architectures with heterogeneous compositions has the potential to revolutionize transplantation of tissues and organs.

Use of an Additional Nonlocking Screw in Olecranon Fracture Osteosynthesis Changes Failure Mechanism.

Hardware-related complications can occur when plate fixation is used to stabilize osteoporotic fractures involving the olecranon. The use of an additional nonlocking screw, placed retrograde into the proximal fracture segment, may improve stability under load. The purpose of this study was to conduct a biomechanical comparison of olecranon repair constructs with and without this additional retrograde screw. Nine matched pairs of elderly fresh-frozen cadaveric upper extremities were used. Two-part olecranon fractures were modeled, and fracture stabilization was performed. Olecranon plates were implanted either with the standard surgical technique (CTRL) or with an additional retrograde screw (EXPT). Dynamic extensions of increasingly loaded forearms were performed, and comparisons of sustained cycles, maximum load, and total work were made. Relative motion of bone segments was tracked, and modes of failure were assessed. Seventy-eight percent of specimens from the CTRL group failed due to relative fragment displacement exceeding 3 mm, while 78% of EXPT specimens failed due to instantaneous catastrophic failure. There were no significant differences in terms of number of survived cycles, maximum load, or work performed between the groups. The addition of a retrograde screw in this plating technique changes the failure mode from fracture displacement to catastrophic failure. The use of a 3.5-mm retrograde screw in the relatively small proximal ulnar fragment should be avoided, but screws with a smaller diameter may still have potential to improve fixation. Further biomechanical and clinical research is necessary to improve strategies for plate fixation of olecranon fractures in the elderly population. [Orthopedics. 2019; 42(1):e74-e80.].

An Exploratory Study Using Semi-Tabular Plate in Zone II Flexor Tendon Repair.

This study evaluated the feasibility of using a low-profile titanium (Ti) plate implant, also known as the Ti-button, for Zone II flexor tendon repair. We hypothesize that the use of the Ti-button can distribute the tensile force on the digital flexor tendons to achieve better biomechanical performance. Twenty lacerated porcine flexor tendons were randomly divided into two groups and repaired using Ti-button or 6-strand modified Lim-Tsai technique. Ultimate tensile strength, load to 2 mm gap force, and mode of failure were recorded during a single cycle loading test. We also harvested twelve fingers with lacerated flexor digitorum profundus tendons from six fresh-frozen cadaver hands and repaired the tendons using either Ti-button method or modified Lim-Tsai technique. A custom-made bio-friction measurement jig was used to measure the gliding resistance and coefficient of friction of the tendon sheath interface at the A2 pulley. The ultimate tensile strength, load to 2 mm gap force, stiffness, and gliding resistance of the Ti-button repairs were 101.5 N, 25.7 N, 7.8 N/mm, and 2.2 N respectively. Ti-button repairs had significantly higher ultimate tensile strength and stiffness than the modified Lim-Tsai repair. However, Ti-button also increased the gliding resistance and coefficient of friction but there was no significant difference between the two repair techniques. Ti-button repair displayed comparable mechanical properties to the traditional repair in terms of 2-mm gap formation and gliding resistance, but with a stronger repair construct. Thus, this deepened our interest to further investigate the potential of using Ti-button implant in Zone II flexor tendon repair by studying both the mechanical and biochemical (tendon healing) properties in more in-depth.

In situ repair technique of infill masonry walls in steel frames damaged after an earthquake

The present paper first reviews the scientific information about masonry buildings in terms of the structural performance of different masonry walls, usual pre-earthquake retrofitting methods, and post-earthquake repair methods. From this, it is found that limited information is available on applicable repair methods for damaged masonry walls after the occurrence of an earthquake event. There is an essential need from the perspective of disaster management strategies to provide urgent aid to casualties of moderate seismic events well before preparing damage assessment data and a comprehensive retrofitting program for the earthquake-affected area. For this reason, three experiments were designed to investigate the effect of brick masonry infill on a simple steel frame and the success rate of a new method of repairing damaged infill. In the proposed repair method, cracks in the damaged masonry infill are stitched by crimped wire meshes in the shape of Band-Aids and cementitious plaster is used to coat the attached wire meshes. The crimped wire meshes must be fastened to the infill with hooked driven nails and must be attached perpendicular to diagonal crack paths and the four corners and centre of the infill. This method is presented for efficient and simple in situ repair interventions to provide temporary residency for casualties. Usage of plasters including accelerated cement or application of accelerated curing methods can reduce the time of repair construction and prepare the proposed method for urgent aids against aftershocks. No inappropriate structural effects of the steel frame-infill interaction were observed during these tests. Furthermore, the results indicated that the repair method not only restored the lost strength of the damaged infill but also recovered the stiffness and ductility of the reference specimen based on the experimental evidence. Following the experiments, a practical design methodology for the required crimped wire mesh specification based on the length of the infill diagonal cracks was recommended.

Gallol-derived ECM-mimetic adhesive bioinks exhibiting temporal shear-thinning and stabilization behavior

3D bioprinting is an attractive technique to fabricate well-organized, cell-laden constructs for tissue repair and disease modeling. Although numerous hydrogel bioinks have been developed, materials are still needed that mimic the cellular microenvironment, have the appropriate viscosity and stabilization for printing, and are cytocompatible. Here, we present a unique gallol-modified extracellular matrix (ECM) hydrogel ink that is inspired by rapid fruit browning phenomena. The gallol-modification of ECM components (e.g., hyaluronic acid, gelatin) allowed (i) immediate gelation and shear-thinning properties by dynamic hydrogen bonds on short time-scales and (ii) further auto-oxidation and covalent crosslinking for stabilization on longer time-scales. The gallol ECM hydrogel ink was printable using an extrusion-based 3D printer by exploiting temporal shear-thinning properties, and further showed cytocompatibility (∼95% viability) and on-tissue printability due to adhesiveness of gallol moieties. Printed cell-laden filaments degraded and swelled with culture over 6 days, corresponding to increases in cell density and spreading. Ultimately, this strategy is useful for designing hydrogel inks with tunable properties for 3D bioprinting. Statement of Significance3D bioprinting is a promising technique for the fabrication of cell-laden constructs for applications as in vitro models or for therapeutic applications. Despite the previous development of numerous hydrogel bioinks, there still remain challenging considerations in the design of bioinks. In this study, we present a unique cytocompatible hydrogel ink with gallol modification that is inspired by rapid fruit browning phenomena. The gallol hydrogel ink has three important properties: i) it shows immediate gelation by dynamic, reversible bonds for shear-thinning extrusion, ii) it allows spontaneous stabilization by subsequent covalent crosslinking after printing, and iii) it is printable on tissues by adhesive properties of gallol moieties. As such, this work presents a new approach in the design of hydrogel inks.

Polymethacrylamide and Carbon Composites that Grow, Strengthen, and Self‐Repair using Ambient Carbon Dioxide Fixation

Plants accumulate solid carbon mass and self-repair using atmospheric CO2 fixation from photosynthesis. Synthetic materials capable of mimicking this property can significantly reduce the energy needed to transport and repair construction materials. Here, a gel matrix containing aminopropyl methacrylamide (APMA), glucose oxidase (GOx), and nanoceria-stabilized extracted chloroplasts that is able to grow, strengthen, and self-repair using carbon fixation is demonstrated. Glucose produced from the embedded chloroplasts is converted to gluconolactone (GL) via GOx, polymerizing with APMA to form a continuously expanding and strengthening polymethacrylamide. The extracted spinach chloroplasts exhibit enhanced stability and produce 12 µg GL mg-1 Chl h-1 after optimization of the temporal illumination conditions and the glucose efflux rate, with the insertion of chemoprotective nanoceria inside the chloroplasts. This system achieves an average growth rate of 60 µm3 h-1 per chloroplast under ambient CO2 and illumination over 18 h, thickening with a shear modulus of 3 kPa. This material can demonstrate self-repair using the exported glucose from chloroplasts and chemical crosslinking through the fissures. These results point to a new class of materials capable of using atmospheric CO2 fixation as a regeneration source, finding utility as self-healing coatings, construction materials, and fabrics.

Double-Layer Rotator Cuff Repair: Anatomic Reconstruction of the Superior Capsule and Rotator Cuff Improves Biomechanical Properties in Repairs of Delaminated Rotator Cuff Tears

Background: Delamination in rotator cuff tears has been identified as a prognostic factor for negative outcome after repair, with a reported prevalence between 38% and 88%. Purpose: To compare biomechanical properties of 3 repair techniques for delaminated rotator cuff tears. Study Design: Controlled laboratory study. Methods: Eighteen fresh-frozen cadaveric shoulders were used to evaluate rotator cuff footprint reconstruction, contact area and pressure, displacement under cyclical loading, and load to failure of 3 double-row repair configurations: double-row suture repair with medial row knots (medially knotted bridge, mkB); knotless double-row repair using suture tapes (knotless bridge, klB); and knotless double-row, double-layer-specific repair (double-layer, DL). Dynamic pressure sensors were used to assess contact patterns at the footprint region in 0°, 30°, and 60° of glenohumeral abduction and 5 rotational positions (0°, 30° of internal rotation, 30° of external rotation, 60° of internal rotation, 60° of external rotation). Optical markers were used to document whole tendon and individual layer displacement after rotator cuff repair under cyclical loading for 200 cycles (10 N to 100 N at 1 Hz). Specimens were then loaded monotonically to failure at a rate of 33 mm/min. Results: Mean contact area and footprint restoration were highest in the DL group at 60° of glenohumeral abduction for all rotational positions (mkB mean ± SD, 195.4 ± 54.3 mm2, 66.7% ± 19.7%; klB, 250.6 ± 34.9 mm2, 76.2% ± 10.3%; DL, 318.4 ± 36.6 mm2, 109.1% ± 24.0%; P < .001). The double-layer-specific repair showed the least displacement under cyclical loading (mkB mean ± SD, 0.53 ± 0.18 mm; klB, 0.79 ± 0.37 mm; DL, 0.31 ± 0.24 mm; P = .029), most closely resembling the native tendon. Peak loads at failure were comparable between repair groups (mkB mean ± SD, 366.92 ± 70.59 N; klB, 280.05 ± 77.66 N; DL, 398.35 ± 109.04 N; P = .083). Conclusion: Anatomic restoration of the superior capsular and tendon insertion in delaminated rotator cuff tears with a double-layer-specific repair configuration demonstrated superior footprint restoration with increasing abduction, while providing construct displacement comparable to the native tendon under cyclical loading. Peak load at failure was comparable between repair constructs. Clinical Relevance: The prevalence and clinical importance of delaminated rotator cuff tears have long been underestimated. Anatomically correct individual reconstruction of the superior capsule and rotator cuff could restore near-native biomechanics and potentially reduce the risk of rotator cuff repair failure.

Remplissage Using Interconnected Knotless Anchors: Superior Biomechanical Properties to a Knotted Technique?

To evaluate the biomechanical fixation strength and gap formation of 2 different remplissage fixation methods (double pulley knotted construct and interconnected knotless repair construct) in cadaver specimens. Seven matched pairs of human cadaveric shoulders were used for testing (mean age, 56 ± 10years). A shoulder from each matched pair was randomly selected to receive a Hill-Sachs remplissage using either a knotted (No. 2 FiberWire double pulley with 3.0-mm SutureTak anchors) or knotless (coreless No. 2 FiberWire interconnected between 3.9-mm knotless CorkScrew anchors) double mattress construct. The tendon was cycled between 10 and 100N at 1Hz for 100 cycles, followed by a single-cycle pull to failure at 33mm/s. Cyclic displacement, load to clinical failure (5mm), yield load, and mode of failure were recorded. Neither construct demonstrated clinical failure under cyclic loading. Load to clinical failure was higher for the knotless repair than that of the knotted repair (788 ± 162N vs 488 ± 227N; P= .003). The yield load was higher for the knotless repair than that of the knotted repair (1,080 ± 298N vs 591 ± 265N; P= .008). The most common failure mode for the knotted repair was knot failure or tendon tearing, whereas the failure mode for the knotless repair was by anchor pull-out or tendon tear with no failures occurring via the interconnected suture construct mechanism. In this biomechanical study comparing cyclic and ultimate loading for 2 double mattress remplissage repairs, the construct using interconnected, knotless sutures outperformed the knotted construct. No failure of the interconnected suture construct mechanism by slippage or breakage was observed in the knotless group. The use of the interconnected knotless suture technique might improve the biomechanical strength of arthroscopic remplissage repairs in treating shoulder instability.

Performance of multiphase scaffolds for bone repair based on two-photon polymerized poly(d,l-lactide-co-ɛ-caprolactone), recombinamers hydrogel and nano-HA

Multiphase hybrids were fabricated from poly(d,l-lactide-co-ɛ-caprolactone) (PLCL) copolymer scaffolds impregnated with silk-elastin-like recombinamers (SELRs) hydrogel containing 2 wt% hydroxyapatite nanoparticles (nHA). The PLCL scaffolds, triply-periodic minimal surface geometry, were manufactured using two-photon stereolithography. In vitro degradation studies were conducted on PLCL scaffolds in inflamed tissue mimic media (pH ~ 4.5–6.5) or phosphate buffered saline (PBS) at 37 °C. Compression test revealed instant shape recovery of PLCL scaffolds after compression to 70% strain, ideal for arthroscopic delivery. Degradation of these scaffolds was accelerated in acidic media, where mass loss and compressive properties at day 56 were about 2–6 times lower than the scaffolds degraded in PBS. No significant difference was seen in the compressive properties between PLCL scaffolds and the hybrids due to the order of magnitude difference between the hydrogels and the PLCL scaffolds. Moreover, degradation properties of the hybrids did not significantly change by inclusion of SELR+/−nHA nanocomposite hydrogels. The hybrids lost approximately 40% and 84% of their initial weight and mechanical properties, respectively after 112 days of degradation. Cytotoxicity assessment revealed no cytotoxic effects of PLCL or PLCL-SELR+/−2%nHA scaffolds on bone marrow-derived human Mesenchymal Stem Cells. These findings highlight the potential of these hybrid constructs for bone and cartilage repair.

The use of suture-tape and suture-wire in arthroscopic rotator cuff repair: A comparative biomechanics study

BackgroundRotator cuff repair surgery aims to create a secure, pressurized tendon-bone footprint to permit re-establishment of the fibrovascular interface and tendon healing. Flat-braided suture-tape is an alternative suture material to traditional suture-wire that has potential to reproduce a larger repair construct contact area. The objective of this study was to compare contact pressure, area as well as the mechanical fatigue strength between suture-wire and suture-tape Suture-bridge repair constructs in an ovine model. MethodsSixty lamb infraspinatus tendons were harvested and randomly allocated to three- and four-anchor Suture-bridge repairs performed using either suture-wire or suture-tape. Thirty-two specimens were cyclically loaded for 200 cycles in an Instron testing machine, while tendon gap formation was recorded using a high speed digital motion analysis system. Loading to failure was then performed to evaluate construct ultimate tensile strength and stiffness. The remaining 28 specimens were assessed for repair contact pressure and area using pressure-sensitive film. ResultsThere was a significantly greater average tendon contact pressure (mean difference: 0.064 MPa, p = 0.04) and area (mean difference: 2.71 mm2, p = 0.03) in fiber-tape repair constructs compared to those in fiber-wire constructs for the three-anchor Suture-bridge configuration. The four-anchor suture-tape constructs had a significantly larger ultimate tensile strength than that of the four-anchor suture-wire constructs (mean difference: 56.4 N, p = 0.04). There were no significant differences in gap formation or stiffness between suture-tape and suture-wire constructs (p > 0.05). ConclusionSuture-tape offers greater pressurised tendon-bone contact than suture-wire in three-anchor Suture-bridge repairs, while greater mechanical strength is achieved with the use of suture-tape in four-anchor Suture-bridge constructs.

Biomechanical Strength of Rotator Cuff Repairs: A Systematic Review and Meta-regression Analysis of Cadaveric Studies

Background: Biomechanical cadaveric studies of rotator cuff repair (RCR) have shown that transosseous equivalent and double-row anchored repairs are stronger than other repair constructs. Purpose: To identify technical and procedural parameters that most reliably predict biomechanical performance of RCR constructs. Study Design: Systematic review. Methods: The authors systematically searched the EMBASE and PubMed databases for biomechanical studies that measured RCR performance in cadaveric specimens. The authors performed a meta-regression on the pooled data set with study outcomes (gap formation, failure mode, and ultimate failure load) as dependent variables and procedural parameters (eg, construct type, number of suture limbs) as covariates. Stratification by covariates was performed. An alpha level of .05 was used. Results: Data from 40 eligible studies were included. Higher number of suture limbs correlated with higher ultimate failure load (β = 38 N per limb; 95% CI, 28 to 49 N) and less gap formation (β = −0.6 mm per limb; 95% CI, −1 to −0.2 mm). Other positive predictors of ultimate failure load were number of sutures, number of mattress stitches, and use of wide suture versus standard suture. When controlling for number of suture limbs, we found no significant differences among single-row anchored, double-row anchored, transosseous equivalent, and transosseous repairs. Higher number of suture limbs and transosseous equivalent repair both increased the probability of catastrophic construct failure. Conclusion: This study suggests that the number of sutures, suture limbs, and mattress stitches in a RCR construct are stronger predictors of overall strength than is construct type. There is a need to balance increased construct strength with higher risk of type 2 failure.

Biomechanical Analysis of All-Suture Anchor Fixation for Rotator Cuff Repair.

Objectives: Suture anchors are commonly utilized during arthroscopic rotator cuff repair (RCR). Recently, all-suture suture-anchor (ASSA) constructs have been introduced for RCR; however, the biomechanical properties of these implants are poorly understood. The purpose of this study was to compare the biomechanical properties of ASSA to conventional suture anchor (CSA) fixation during RCR. Methods: Fourteen fresh-frozen matched pair human cadaveric shoulders (average age 52 ± 13 years) with no documented prior rotator cuff tears or shoulder surgery were dissected. The supraspinatous tendon was isolated and detached from its footprint, and then was repaired in an anatomical position. Specimens were randomized into two repair constructs: Q-FIX double-loaded ASSA (N=7) and TWINFIX double-loaded conventional suture anchor (CSA) (N=7) (Smith &amp; Nephew, Andover, MA). Each construct was cyclically loaded from 10 to 160 N for 100 cycles at 100N/s, and then pulled to failure at 1mm/s starting from the zero position. Load, crosshead displacement, failure mode, and time were recorded. Correlations between BMD, tendon gage length, maximum load, and stiffness were assessed. The groups were statistically analyzed with independent samples t-test, Fisher’s exact test, and a linear regression analysis, with p&lt;0.05 considered significant. Results: There was no statistically significant difference in maximum load (ASSA: 617.73±177.8, CSA: 545.13±212.98 N, p=0.339), cyclic extension (ASSA: 7.88±1.33, CSA: 8.49±2.14 mm, p=0.117), construct stiffness (ASSA: 62.43±11.06, CSA: 68.14±10.77 N/mm, p=0.973), or extension at maximum load (ASSA: 17.03±4.73, CSA: 15.45±1.73 mm, p=0.122) between the ASSA and CSA groups. Failure modes consisted of suture tearing out of the tendon (ASSA: N=3, CSA: N=3) and anchor pull out (ASSA: N=4, CSA: N=4), with no difference in failure mode between groups (p=0.99). An association trended towards significance between higher BMD and higher maximum load in the CSA group (p=0.053) but not the ASSA group (p=0.125) Conclusion: ASSA constructs for RCR have similar biomechanical properties compared to CSA constructs. Additional clinical data is necessary to determine if these biomechanical results can be translated clinically.