Anchor Pullout Research Articles

Suture anchor and transtibial pullout refixation of the posterior medial meniscus root tears restore tibiofemoral contact pressure and area to intact meniscus levels.

To compare the load distributed to the medial tibial articular cartilage after refixation of posterior medial meniscus root tears between the suture anchor and transtibial pullout techniques in posterior medial meniscus root tears. Twelve Thiel's embalmed human cadaveric knees are used and divided into three groups (four knees in each group): (1) intact meniscus (IM), (2) fixation with suture anchor technique (SA) and (3) fixation with transtibial pullout technique (TP). Each group applies an axial compression load up to 1500 N by Instron E 10000 at two knee flexion angles (0° and 60°). A Tekscan 4000 pressure sensor is used to record the contact pressure and the contact area for each testing condition. The contact pressure and the contact area between the three conditions are not significantly different at 0° and 60° knee flexion angles. The peak contact pressure and contact area are 3734.8 ± 2642.2 kPa, 288.2 ± 115.0 mm2, 4510 ± 2930.5 kPa, 204.4 ± 36.8 mm2 and 5328.8 ± 2607.7 kPa, 219.2 ± 84.7 mm2 in IM, SA and TP, respectively. Both suture anchor and transtibial pullout refixation of PMMRT can restore contact pressure and contact area similar to the intact meniscus. This finding suggests that either technique can be reliably used in clinical practice to preserve joint function and potentially reduce the risk of osteoarthritis progression following posterior medial meniscus root tear repairs. Level III.

Biomechanical Comparison of Suture-Relay All-Suture Anchors and Conventional Suture Anchors for Posterior Medial Meniscus Root Repair in Porcine Models.

Posterior medial meniscus root (PMMR) tears (PMMRTs) can be repaired using various techniques to promote healing. However, the biomechanical properties of suture-relay all-suture anchor (ASA) versus conventional suture anchor (CSA) and loop-locking transtibial pullout (TTP) have not been well established. To compare the biomechanical properties of PMMR repairs using suture-relay ASA, CSA, and loop-locking TTP. Controlled laboratory study. A total of 33 fresh-frozen porcine knee joints with intact medial menisci were randomly divided into 3 groups, with 11 specimens in each group: ASA, CSA, and TTP. The study involved cyclic loading, with displacement measurements taken after 100, 500, and 1000 cycles. Subsequently, the specimens were loaded until clinical failure (defined as 3-mm displacement) and then to ultimate failure of the construct, with data recorded for displacement after cyclic loading, load to 3-mm displacement, and ultimate load to failure. After 1000 cyclic loadings, the suture-relay ASA group showed considerably less displacement than the loop-locking TTP group (1.8 ± 0.7 mm vs 2.9 ± 0.3 mm; P < .001), but the displacements did not differ considerably between the suture-relay ASA and CSA groups (2.2 ± 0.9 mm; P > .05). The mean loads to clinical failure were significantly greater in the suture-relay ASA and CSA groups (61.3 ± 6.5 and 57.5 ± 9.7 N, respectively) than in the loop-locking TTP group (38.3 ± 9.4 N; P < .05). The ultimate load to failure was significantly greater in the suture-relay ASA group than in the loop-locking TTP group (153 ± 55.1 N vs 102 ± 12.9 N; P < .05). All specimens in the loop-locking TTP group failed by suture elongation mode, whereas only 2 specimens (18%) in the suture-relay ASA group and 5 specimens (45%) in the CSA group failed by suture elongation. Nine specimens (82%) in the suture-relay ASA group and 6 specimens (55%) in the CSA group failed due to suture cutout through the meniscal tissue. The biomechanical properties after PMMR repair did not statistically differ between the suture-relay ASA and CSA groups. The suture-relay ASA technique had a higher load to failure than the loop-locking TTP technique. The suture-relay ASA technique is a promising option for the repair of PMMRTs; its repairing strength is also comparable to that of the CSA technique. Notably, the suture-relay ASA technique can be utilized without establishing a posteromedial portal, resulting in decreased procedure time and mitigating challenges associated with working from the posterior aspect of the knee.

Management of Rotator Cuff Tears in Severely Osteoporotic Patients

Management of rotator cuff tears (RCT) in osteoporotic patients presents significant challenges for treating clinicians because of compromised bone quality. We present a case series of 2 patients with RCT and severe osteoporosis highlighting the complexities of operative and nonoperative management and underscoring the importance of preoperative optimization and careful surgical planning in this vulnerable population. Patient 1 experienced initial improvement postarthroscopic RCT repair but required revision surgery because of anchor pullout, with eventual conversion to reverse total shoulder arthroplasty. Patient 2 faced intraoperative challenges because of previously undiagnosed osteoporosis, leading to difficulties in securely placing suture anchors, and was referred to the fracture liaison service (FLS) for osteoporosis management postoperatively. A multifaceted approach integrating preoperative optimization, advanced surgical techniques, and postoperative management is advised to improve operative success. Extensive perioperative bone quality assessments and augmentation strategies are warranted, including medication comanagement through an FLS if available. Detailed surgical planning is crucial, focusing on arthroscopic repair technique while considering various anchor factors to mitigate failure including proper placement, design, and pullout analysis. Intraoperative bone augmentation with materials such as calcium phosphate, magnesium phosphate, and polymethyl methacrylate cements significantly improves anchor fixation strength in osteoporotic bone. Consideration of a transosseous approach and potential for conversion to an open procedure is also an option when necessary. This review highlights the unique challenges and potential options available to treating clinicians when managing RCT in osteoporotic patients. Continued research and refinement of emerging treatment strategies are essential to improve outcomes and quality of life in this patient population.

Seismic Retrofit Case Study of Shear-Critical RC Moment Frame T-Beams Strengthened with Full-Wrap FRP Anchored Strips in a High-Rise Building in Los Angeles

This paper discusses the iteration of a seismic retrofit solution for shear-deficient end regions of 19 reinforced concrete (RC) moment-resisting frame (MRF) T-beams located in a 12-story RC MRF building in downtown Los Angeles, California. Local strengthening with externally bonded (EB) fiber-reinforced polymer (FRP) fabric was chosen as the preferred retrofit strategy due to its cost-effectiveness and proven performance. The FRP-shear-strengthening scheme for the deficient end-hinging regions of the MRF beams was designed and evaluated through large-scale cyclic testing of three replica specimens. The specimens were constructed at 4/5 scale and cantilever T-beam configurations with lengths of 3.40 m or 3.17 m. The cross-sectional geometry was 0.98 × 0.61 m with a top slab of 1.59 m in width and 0.12 m in thickness. Applied to these specimens were three different retrofit configurations, tested sequentially, namely: (a) unanchored continuous U-wrap; (b) anchored continuous U-wrap with conventional FRP-embedded anchors at the ends; and (c) fully closed external FRP hoops made of discrete FRP U-wrap strips and FRP through-anchors that penetrate the top slab and connect both ends of the FRP strips, combined with intermediate crack-control joints. The strengthening concept with FRP hoops precluded the premature debonding and anchor pullout issues of the two more conventional retrofit solutions and, despite a more challenging and labor-intensive installation, was selected for the in-situ implementation. The proposed hooplike EB-FRP shear-strengthening scheme enabled the deficient MRF beams to overcome a 30% shear overstress at the end-yielding region and to develop high-end rotations (e.g., 0.034 rad [3.4% drift] at peak and 0.038 rad [3.8% drift]) at strength loss for a beam that, otherwise, would have prematurely failed in shear. These values are about 30% larger than the ASCE 41 prescriptive value for the Life Safety (LS) performance objective. Energy dissipation achieved with the fully closed scheme was 108% higher than that of the unanchored FRP U-wrap and 45% higher than that of the FRP U-wrap with traditional embedded anchors. The intermediate saw-cut grooves successfully attracted crack formation between the strips and away from the FRP reinforcement, which contributed to not having any discernable debonding of the strips up to 3% drift. This paper presents the experimental evaluation of the three large-scale laboratory specimens that were used as the design basis for the final retrofit solution.

Comparison of Cast-in place Pullout Anchor Pullout Capacity to Post- Installed Concrete Drill Model and Drill Bit Extractor Concrete (DBEC) Model

Comparison of Cast-in place Pullout Anchor Pullout Capacity to Post- Installed Concrete Drill Model and Drill Bit Extractor Concrete (DBEC) Model

A stacking machine learning model for predicting pullout capacity of small ground anchors

Small ground anchors are widely used to fix securing tents in disaster relief efforts. Given the urgent nature of rescue operations, it is crucial to obtain prompt and accurate estimations of their pullout capacity. In this study, a stacking machine learning (ML) model is developed for the rapid estimation of pullout capacity offered by small ground anchors used for temporary tents, leveraging cone penetration data. The proposed stacking model incorporates three ML algorithms as the base regression models: K-nearest neighbors (KNN), support vector regression (SVR), and extreme gradient boosting (XGBoost). A dataset comprising 119 in-situ anchor pullout tests, where the cone penetration data were measured, is utilized to train and assess the stacking model performance. Three metrics, i.e., coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE), are employed to evaluate the predictive accuracy of the proposed model and compare its performance against four popular ML models and an empirical formula to highlight the advantages of the proposed stacking approach. The results affirm that the proposed stacking model outperforms other ML models and the empirical approach as achieving higher R2 and lower MAE and RMSE and more predicted data points falling within 20% error line. Thus, the proposed stacking model holds promising potential as a solution for efficiently predicting the pullout capacity of small ground anchors.

Fixation failure and early loss of reduction with the use of suture anchors for surgical repair of acromioclavicular joint dislocation: a case series

IntroductionSuture anchors have been used in surgical repair of acromioclavicular joint (ACJ) dislocation. While some reports indicate favorable results, others emphasize less promising outcomes. This case series reports our experience with suture anchors for surgical treatment of ACJ dislocation. MethodsClinical and radiographic outcomes in three patients treated operatively for ACJ dislocations were reviewed. In all patients, two suture anchors were inserted in the coracoid (unicortical) and #5 non- absorbable suture from the suture anchor was shuttled through drill holes in the clavicle and tied over two button devices. The coracoclavicular (CC) ligaments were reconstructed using a figure of eight semitendinosus allograft around the coracoid and clavicle. Postoperatively, sling immobilization was used for 6 weeks, and physical therapy was initiated at 6 weeks with contact activity allowed at 6 months. ResultsThree male patients underwent treatment for Rockwood type 3 (chronic; n=1) and type 5 (n=2) ACJ dislocations. Loss of reduction was noted within 6 weeks postoperatively. Two patients exhibited failure due to complete suture anchor pullout and the third patient had partial pull out of one of the anchors. Additionally, the third patient also suffered a coracoid fracture adjacent to the anchor’s placement after sustaining direct trauma to his shoulder, one-year postoperatively. ConclusionIn our case series, we found a high rate of fixation failure and early loss of reduction with the use of suture anchors for the treatment of ACJ dislocation. These findings should be taken into consideration when selecting an appropriate implant for fixation of ACJ dislocation.

Experimental and numerical investigations on tensile failure mechanism and load-bearing capacity of expansion anchors under pull-through failure mode in HPSFRC

Pull-through(PT) is a unique failure mode of torque-controlled expansion(TCE) anchor after being pulled out from concrete. No universal design formula is available for predicting tensile bearing capacity of anchor of PT mode. In normal concrete(NC), PT failure usually occurs at large embedment depths(Hef), which is uncommon in the field and received less attention than the concrete breakout failure. However, due to the improved mechanical performance of the substrate, the PT mode dominates for anchors in high-performance steel fiber reinforced concrete(HPSFRC) substrate (even at small Hef). In this study, to study the PT mode in HPSFRC, the results of 34 PT failures from previous tests, including testing scenarios with different anchor diameters(D), Hef, and fiber contents(vf), are analyzed. The cracking morphology and load-bearing capacity distribution of PT mode are elaborated. Further, finite element models(FEM) of anchor pullout behavior in HPSFRC is established, which accurately identified different failure modes. The calculated Nu by FEM agree well with the tested Nu. The difference in damage domain between different failure modes is mainly reflected in the unloading stage. Parametric analyses were conducted on pre-tightening torque(Tini), Hef, D, sleeve length(Lsleeve), anchor cone width, anchor cone length(Lcone), and vf to study their influences on Nu of PT mode. Except for Lsleeve and Lcone, which do not affect Nu, changes in other factors can cause linear or nonlinear changes in Nu. The non-linear relationship between Nu and experimental parameters is formulated. Accordingly, a new prediction model that can accurately predict Nu of PT mode for anchors in HPSFRC is developed, of which calibration factors are derived using probability functions.

Oblique pullout of strip anchor embedded in layered sandbed

Oblique pullout of strip anchor embedded in layered sandbed

All-suture anchor size and drill angle influence load to failure in a porcine model of subpectoral biceps tenodesis, a biomechanical study

BackgroundTenodesis of the long head of the biceps tendon is frequently performed in shoulder surgery, and all-suture anchors have become more popular as fixation methods. However, uncertainty still exists regarding the ultimate load to failure of all-suture anchors and the best insertion angle at a cortical humeral insertion point.PurposeThe purpose of this study was to compare the biomechanical characteristics of three types of all-suture anchors frequently used for biceps tenodesis. In addition, the influence of two different insertion angles was observed in a porcine humeri model.MethodsThe ultimate load to failure and failure mode of three types of all-suture anchors (1.6 FiberTak®, 1.9 FiberTak®, 2.6 FiberTak®, Arthrex®) applicable for subpectoral biceps tenodesis were evaluated at 90° and 45° insertion angles in 12 fresh-frozen porcine humeri. The anchors were inserted equally alternated in a randomized manner at three different insertion sites along the bicipital groove, and the suture tapes were knotted around a rod for pullout testing. In total, 36 anchors were evaluated in a universal testing machine (Zwick & Roell).ResultsThe 2.6 FiberTak® shows higher ultimate loads to failure with a 90° insertion angle (944.0 N ± 169.7 N; 537.0 N ± 308.8 N) compared to the 1.9 FiberTak® (677.8 N ± 57.7 N; 426.3 N ± 167.0 N, p-value: 0.0080) and 1.6 FiberTak® (733.0 N ± 67.6 N; 450.0 N ± 155.8 N, p-value: 0.0018). All anchor types show significantly higher ultimate loads to failure and smaller standard deviations at the 90° insertion angle than at the 45° insertion angle. The major failure mode was anchor pullout. Only the 2.6 FiberTak® anchors showed suture breakage as the major failure mode when placed with a 90° insertion angle.ConclusionsAll three all-suture anchors are suitable fixation methods for subpectoral biceps tenodesis. Regarding our data, we recommend 90° as the optimum insertion angle.Clinical relevanceThe influence of anchor size and insertion angle of an all-suture anchor should be known by the surgeon for optimizing ultimate loads to failure and for achieving a secure fixation.

Installation Disturbance of Helical Anchor in Dense Sand and the Effect on Uplift Capacity Based on Discrete Element Method

Helical anchors have been extensively employed as foundation systems for carrying tension loads due to their installation efficiency and large uplift capacity. However, the installation influences of helical anchors are still not well understood, especially for multi-helical anchors. The matrix discrete element method was used to model the process of helical anchor penetration and pull-out in dense sand to investigate the effects of the anchor geometry and advancement ratio (AR, the relative vertical movement per rotation) on soil disturbance, the particle flow mechanism, and the uplift capacity. For shallow helical anchors, the overall disturbance zone is the shape of an inverted cone after installation, while for deep helical anchors, it is funnel-shaped. The advancement ratio has significant effects on the soil particle movement and uplift capacity of helical anchors. The soil particle flow mechanism around helical plates has been identified for single-helix anchors at various advancement ratios, and for double-helix anchors, the influence of the top plate on particle movement during installation was investigated. The uplift capacities of both single- and double-helix anchors increase with the decrease in the AR (AR = 0.5~1), and the influence decreases with the anchor embedment ratio. The efficiency of double-helix anchors induced by installation is close to 1 at pitch-matched installation (AR = 1), indicating that the impact of the top plate during installation is minimal in this case.

Feasibility Study of Steel Derailment Containment Provisions through Quasi-Static Experiments

Railway derailments present a safety hazard, carrying the potential for severe consequences for both human lives and the economy. Implementing derailment containment provisions (DCPs) near the track centerline is essential for mitigating risks in operating high-speed rail (HSR) while providing significant advantages for the large-scale upgrade of existing railway infrastructure. Therefore, this paper investigated the feasibility of a DCP system made of steel through quasi-static experiments, aiming to enhance safety in HSR operations. Initially, single anchor tests were conducted to assess its capacity to withstand applied loads, prevent the pullout of steel anchors, and avoid the local rotation of the steel frame. Then, full-scale steel DCP systems were manufactured and tested for quasi-static load at different locations, including the mid-anchor, the mid-span, and the end-anchor. The relationship between applied load and displacement, along with the initial stiffness of the DCP specimens, was discussed. The findings revealed that the single anchor can withstand an applied load of up to 197.9 kN. The DCP specimen maintained structural integrity at the 207 kN target load under all load scenarios, showing a maximum displacement of 8.93 mm in the case of applied load at mid-span. Furthermore, the initial stiffness of the DCP systems was 1.77 to 2.55 times greater than that of a single anchor, validating a force-bearing coordination mechanism among neighboring anchors and the substantial impact of the applied load positions on their stiffness.

Biomechanical Comparison of Coracoclavicular Fixation Using Metallic Versus All-Suture Anchors.

A coracoclavicular (CC) fixation technique using an all-suture anchor with the assistance of fluoroscopy can prevent iatrogenic anterior deltoid detachment from the clavicle; however, soft anchor pullout has been reported as a complication. To compare the biomechanical properties of conventional metallic and all-suture anchors for CC suture fixation. Controlled laboratory study. A total of 24 fresh-frozen cadaveric specimens were divided into 2 groups: metal anchor group (group M) and all-suture anchor group (group A). In group M, 5.0-mm metallic suture anchors were used for CC fixation, whereas 2.8-mm all-suture anchors were used in group A. The prepared specimens were mounted on a materials testing machine. After preconditioning at 0 to 20 N for 10 cycles, the specimens were subjected to cyclic loading from 20 to 70 N for 1000 cycles. Finally, all the specimens were loaded to failure. Cyclic elongation, linear stiffness, ultimate load, and failure modes were recorded, and the Mann-Whitney U test was used to compare nonparametric parameters between the 2 groups. All of the specimens completed the cyclic loading test. The elongation after cyclic loading in group M (1.6 ± 0.6 mm) was significantly smaller compared with that in group A (2.5 ± 1.2 mm) (P = .02). No between-group differences were found in linear stiffness (42 ± 17 N/mm in group M and 41 ± 17 N/mm in group A). The ultimate failure load in group M (263 ± 66 N) was significantly greater than that in group A (177 ± 76 N) (P = .02). All specimens failed because of suture anchor pullout. The use of all-suture anchors in CC fixation resulted in significantly greater cyclic displacement and smaller ultimate failure load than that of metallic anchors. Understanding the most biomechanically sound suture anchor may assist in lowering the risk of clinical failure in CC fixation and repair.

Numerical simulation analysis of anchor pullout under radial pressurization of anchor solid

The rock structure of weak rock formation is loose with low strength, which is easy to deform. Due to insufficient elongation and bearing capacity, anchor anchorage system damage is frequent and serious. Given the above problems, this paper researches the radial increase in compressive stress anchoring mechanism and uses finite element software ABAQUS simulation algorithms to obtain different radial pressurization conditions under the deformation of the surrounding rock law and the anchor pulling the anchor and the surrounding rock displacement stress change rule. The results show that when applying the radial pressure of 1.5 MPa, the surrounding rock and the anchor stress reach their maximum value, and the displacement reaches its minimum value. Field testing and monitoring results show that radial pressurized anchors can effectively control the deformation of the roadway perimeter rock and improve the anchoring effect.

Do Pedicle Screws That Terminate in the Costovertebral Joint Compromise Proximal Anchor Fixation in a Dual Growing Rod Construct?

Growing rods (GRs) are used to treat early-onset scoliosis (EOS) recalcitrant to bracing and casting. Proximal anchor pullout, a known complication of GR constructs, can result in spinal cord injury if pedicle screw anchors are placed with a lateral-to-medial trajectory. To mitigate this risk, a more straightforward and potentially safer trajectory may result in screws that terminate within the costovertebral joint (CVJ). We asked, how often does CVJ placement occur and does this technique increase the rate of failure in GR constructs? We retrospectively reviewed 35 patients with EOS treated with dual GR with >2-year follow-up excluding patients with skeletal dysplasia or history of previous posterior instrumentation. Patient demographics, radiographic parameters, and implant constructs were assessed. Of patients meeting the inclusion criteria, 18/35 (51%) were females with an average age of 7.96 (range: 4.0 to 15.2) years at surgery with a follow-up of 3.7 (range: 2.0 to 7.7) years. Five (14%) patients had idiopathic EOS, 5 (14%) had congenital EOS, 12 (34%) had neuromuscular EOS, 10 (29%) had syndromic scoliosis, and 3 (9%) had another etiology for EOS. Among 195 proximal pedicle screws placed, 19 (10%) terminated within the CVJ, and 13 patients (37%) had at least 1 CVJ screw. Two patients (6%) experienced unilateral proximal pullout. In both patients, the anchors on the affected side included 1 of 2 screws within the CVJ. Both patients had constructs that included 2 screws on the side that pulled out and 3 screws on the side that did not. None of the remaining 17 CVJ screws led to implant failure. Pedicle screw placement within the CVJ is common and does not appear to significantly contribute to proximal screw pullout; however, it may contribute to unilateral implant failure in constructs employing only 2 proximal screws, where 1 of those 2 screws terminates within the CVJ. Construct modifications should be considered in this scenario. Level III.

Evaluasi dan Analisis Struktur Beton pada Jembatan Kalikuto di Ruas Jalan Tol Batang Semarang

The structural strength of a bridge is critical for the safety and security of road users, particularly on toll roads. The existing concrete structure must be evaluated on a regular basis as part of the bridge's health inspection. The concrete structure of the Kalikuto Bridge, which is part of the Batang Semarang Toll Road, is evaluated and analyzed in this study. The combination of destructive and non-destructive tests (DT and NDT), such as mapping concrete strength using a core drill and hammer test, concrete density with Ultrasonic Pulse Velocity (UPV), and reinforcement configuration using a rebar scanner. Meanwhile, the carbonation and corrosion of concrete materials were also evaluated. The finite element method software was used to analyze the concrete tensile strength against anchor pullout. Overall, the structural condition of the Kalikuto Bridge is still very good for land transportation routes until the building's design service life, i.e. compressive strength according to specifications, concrete density about 4356.67 – 5275.33 m/s, rebar configuration according to as built drawing, no carbonation and no corrosion in more than 90% of the structure. Anchor pullout will not occur since the tensile force does not exceed simulation results. Periodic maintenance is required to protect the bridge structure from things that can reduce the concrete strength.

Influence of type of geosynthetic material interaction on shallow anchor pullout capacity

A series of laboratory model pullout tests were performed in the present study on poorly graded sands having different properties of S1 and S2, at a relative density (Rd) of 70%. The tests were performed in a test tank having a size of 1000 mm × 1000 mm × 1000 mm using a circular-shaped anchor size (D) of 100 mm. The depth (L) of the anchor plate during the model tests was maintained as shallow i.e., L/D = 4. To improve the plate anchor uplift capacity, the lab scale model tests were performed in sand beds of S1 and S2 using low tensile strength polypropylene geotextile (PPGT) as a reinforcement material. Furthermore, a series of openings were made to the PPGT which is named GOP (geotextile with openings) to act as a geogrid material. Irrespective of the type of sand and reinforcement, a single number of reinforcement layers having a size of 5D was used and placed directly above the anchor plate for all the model tests. The test results revealed that sand S1 shows higher improvement compared to sand S2 for both the cases of unreinforced and PPGT geotextile reinforced conditions. It happened due to the soil physical property of higher unit weight of soil of S1. Furthermore, the anchor ultimate pull-out capacity of sand S1 with GOP is 1.63 and 1.15 times higher than that of unreinforced and PPGT geotextile-reinforced sands. Even though, the tensile strength and stiffness of GOP in comparison with PPGT is almost lesser than a factor of 3. It could be happened due to the difference in the soil-geosynthetic interactions and reinforcement mechanisms.

Development of in vitro osteoporosis model in minipig proximal humerus and femur: validation in histological and biomechanical study

BackgroundThe minipig has been used for research in various fields of medicine, even in orthopedics. Though previous studies have already suggested other methods to create osteoporotic bone, those methods had some disadvantages for taking time and efforts. Therefore, we aimed to generate osteoporotic proximal humerus and proximal femur of minipig using EDTA solution and validate their properties through dual energy X-ray absorptiometry (DEXA), micro-CT study, histological and biomechanical ways.MethodsSix minipigs were used. Out of a total of 12 proximal humerus (PH) and 12 proximal femurs (PF), 6 PH and 6 PF were used as the decalcified group and the opposite side as the non-decalcified group. In vitro decalcification with Ca-chelating agents (0.5 M EDTA solution, pH 7.4) was used. Area BMD (aBMD) was measured using DEXA, Volumetric BMD (vBMD), and microstructure were measured using micro-CT. Universal testing machine was used to measure ultimate load to failure (ULTF). Each group was compared using two types of suture anchors (all-suture anchor, ASA, and conventional screw type anchor, CA).ResultsThere was a significant difference in aBMD and cortical thickness (aBMD: decalcified, 0.433 ± 0.073 g/cm2, undecalcified, 0.962 ± 0.123 g/cm2, p < 0.001; cortical thickness: decalcified, 0.33 ± 0.34 mm, undecalcified, 1.61 ± 0.45 mm, p < 0.001). In the case of ASA, the ULTF was significantly lower in the decalcified group (decalcified: 176.6 ± 74.2 N, non-decalcified: 307.7 ± 116.5 N, p = 0.003). In the case of CA, there was no significant difference (decalcified: 265.1 ± 96.0 N, undecalcified: 289.4 ± 114.5 N, p = 0.578).ConclusionWe demonstrated that decalcification with EDTA solution significantly decreased aBMD, vBMD, and cortical thickness. Decalcified minipig bone using EDTA resulted in similar biomechanical properties as osteoporotic human bone with respect to anchor pull-out.

Techniques and Tips to Arthroscopically Remove Prominent and Loose Shoulder Joint Hardware

The number of arthroscopic shoulder operations has continued to steadily increase in recent years, with a projection of over 500,000 rotator cuff operations in 2023. Although the incidence of anchor pullout, hardware failure, and aberrant hardware placement is relatively low, this increased volume of shoulder operations has inevitably resulted in a consequent increase in the number of patients who experience such hardware complications. These hardware issues can cause significant pain, limit shoulder function, and cause permanent damage to the shoulder articular cartilage. The described arthroscopic techniques are presented to provide tools and strategies to safely and effectively remove prominent and loose shoulder joint hardware.

Sublaminar Band Fixation Provides Excellent Anchors for MAGEC Rod Distraction Systems.

MAGEC rods (NuVasive) provide distraction growth in early-onset scoliosis. Pedicle screw use with MAGEC rods can lead to anchor failure. Sublaminar bands offer superior fixation points for the MAGEC system while preserving pedicles and facets, avoiding spinal cord injury, and eliminating the need for fluoroscopy. Sublaminar bands can be safely used up to cervical vertebra four (C4), substantially decreasing the risk of complications such as anchor pull-out, rod breakage, and proximal junctional kyphosis that typically occurs with pedicle screws and hooks. This case demonstrates the viable option of sublaminar band fixation as an anchor system for MAGEC rods. This is a retrospective case review of one patient with early-onset scoliosis who underwent multiple osteotomies, spinal cord decompression, and placement of MAGEC rods with sublaminar bands. The patient had successful distraction procedures conducted routinely throughout a 44-month period with no associated implant complications or neurologic sequelae during that period. The patient had achieved maximal distraction with the implanted rods and thereafter underwent removal of the MAGEC rods and replacement implantation with longer MAGEC rods. The purpose of this case review was to demonstrate the superior fixation results provided with sublaminar band fixation for MAGEC rod distraction systems.