Bone Staples Research Articles

Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models

ABSTRACT Aim To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog. Methods Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured. Results In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally). Conclusions In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction. Clinical relevance These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

Comparison of Time-Zero Primary Stability Between a Biodegradable Magnesium Bone Staple and Metal Bone Staples for Knee Ligament Fixation: A Biomechanical Study in a Porcine Model.

Bone staples have been shown previously to be a viable modality for cortical tendon graft fixation in ligament knee surgery. However, soft tissue reactions have been reported, making implant removal necessary. Magnesium alloys are a promising material for biodegradable orthopaedic implants, with mechanical properties closely resembling those of human bone. To compare the primary stability of a biodegradable bone staple prototype made from magnesium to bone staples made from metal in the cortical fixation of tendon grafts during knee surgery. Controlled laboratory study. Primary stability of peripheral tendon graft fixation was assessed in a porcine model of medial collateral ligament reconstruction. Two commercially available metal bone staples (Richards fixation staple with spikes [Me1] and spiked ligament staple [Me2]) were compared with a magnesium bone staple prototype for soft tissue fixation. Primary stability was assessed using a uniaxial materials testing machine. Cyclic loading at 50 and 100 N was applied for 500 cycles each, followed by load-to-failure testing. After 500 cycles at 50 N, elongation was 1.5 ± 0.5 mm in the Me1 group, 1.9 ± 0.5 mm in the Me2 group, and 1.8 ± 0.4 mm in the magnesium group. After 1000 cycles of loading (500 cycles at 50 N and 500 at 100 N), elongation was 3.6 ± 0.9 mm in the Me1 group, 3.5 ± 0.6 mm in the Me2 group, and 4.1 ± 1.0 mm in the magnesium group. No significant differences regarding elongation were found between the groups. Load to failure was 352 ± 115 N in the Me1 group, 373 ± 77 N in the Me2 group, and 449 ± 92 N in the magnesium group, with no significant difference between the groups. In this study, the magnesium bone staples provided appropriate time-zero biomechanical primary stability in comparison with metal bone staples and may therefore be a feasible alternative for cortical fixation of tendon grafts in knee surgery. The biodegradability of magnesium bone staples would eliminate the need for later implant removal.

Determining the Mechanical Properties of Super-Elastic Nitinol Bone Staples Through an Integrated Experimental and Computational Calibration Approach.

Super-elastic bone staples have emerged as a safe and effective alternative for internal fixation. Nevertheless, several biomechanical aspects of super-elastic staples are still unclear and require further exploration. Within this context, this study presents a combined experimental and computational approach to investigate the mechanical characteristics of super-elastic staples. Two commercially available staples with distinct geometry, characterized by two and four legs, respectively, were examined. Experimental four-point bending tests were conducted to evaluate staple performance in terms of generated forces. Subsequently, a finite element-based calibration procedure was developed to capture the unique super-elastic behavior of the staple materials. Finally, a virtual bench testing framework was implemented to separate the effect of geometry from that of the material characteristics on the mechanical properties of the devices, including generated force, strain distribution, and fatigue behavior. The experimental tests indicated differences in the force vs. displacement curves between staples. The material calibration procedure revealed marked differences in the super-elastic properties of the materials employed in staple 1 and staple 2. The results obtained from the virtual bench testing framework have showed that both geometric features and material characteristics had a substantial impact on the mechanical properties of the device, especially on the generated force, whereas their effect on strain distribution and fatigue behavior was comparatively less pronounced. To conclude, this study advances the biomechanical understanding of Nitinol super-elastic staples by separately investigating the impact of geometry and material characteristics on the mechanical properties of two commercially available devices.

Biomechanical comparison of bone staple techniques for stabilizing tibial tuberosity fractures

This study compared the biomechanical properties of bone-stapling techniques with those of other fixation methods used for stabilizing tibial tuberosity fractures using 3-dimensionally (3D)-printed canine bone models. Twenty-eight 3D-printed bone models made from computed tomography scan files were used. Tibial tuberosity fractures were simulated using osteotomy. All samples were divided into 4 groups. Group 1 was stabilized with a pin and tension-band wire; group 2, with a pin and an 8 mm-wide bone staple; group 3, with 2 horizontally aligned pins and an 8 mm-wide bone staple; and group 4 with a 10 mm-wide bone staple. Tensile force was applied with vertical distraction until failure occurred. The load and displacement were recorded during the tests. The groups were compared based on the load required to cause displacements of 1, 2, and 3 mm. The maximum failure loads and modes were recorded. The loads at all displacements in group 4 were greater than those in groups 1, 2, and 3. The loads at 1, 2, and 3 mm displacements were similar in groups 1 and 3. There was no significant difference between groups 1 and 3. Groups 1 and 4 provided greater maximum failure loads than groups 2 and 3. Failure occurred because of tearing of the nylon rope, tibial fracture, wire breakage, pin bending, and fracture around the bone staple insertion. In conclusion, these results demonstrate that the bone-stapling technique is an acceptable alternative to tension-band wire fixation for the stabilization of tibial tuberosity fractures in canine bone models.

The Biomechanical Stability of Bone Staples in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction Depends on the Implant Design

Background: The promising biomechanical stability of bone staples (BSs) in cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction has been revealed by a previous investigation. However, it is currently unknown if the biomechanical stability of cortical fixation of tendon grafts depends on the BS design. Purpose: To assess the biomechanical stability of cortical fixation of tendon grafts in knee surgery using 4 different BS designs. Study Design: Controlled laboratory study. Methods: Cortical fixation of tendon grafts was performed in a porcine knee model at the tibial insertion area of the MCL using 4 different BS designs (n = 40): 8-mm width without spikes (n = 10), 8-mm width with spikes (n = 10), 14-mm width with spikes (n = 10), and 13 mm–wide 4-prong staples with spikes (n = 10). Specimens were mounted in a materials testing machine, and cyclic loading was applied to the tendon graft (500 cycles at 50 and 100 N, respectively), followed by load-to-failure testing. The Kruskal-Wallis test was performed for statistical analysis (P < .05), and the post hoc Dunn test was performed for multiple comparisons. Results: In 4 of 10 specimens with graft fixation using BSs without spikes, slippage of the tendon underneath the BS led to failure of the construct during cyclic loading to 100 N. In the other groups, no fixation failure was observed during cyclic loading. Furthermore, graft fixation using BSs without spikes was found to have significantly more elongation during cyclic loading (8.2 ± 1.9 mm) and a lower ultimate failure load (170 ± 120 N) compared with graft fixation using narrow BSs with spikes (3.4 ± 1.2 mm [P < .0001] and 364 ± 85 N [P < .05], respectively) and graft fixation using broad BSs with spikes (4.5 ± 1.4 mm [P < .05] and 429 ± 67 N [P < .001], respectively). No statistical differences in elongation during cyclic loading or ultimate failure load were found between 4-prong staples with spikes (5.0 ± 1.3 mm and 304 ± 85 N) and narrow or broad staples with spikes. Conclusion: The biomechanical stability of cortical fixation of an MCL graft was comparable between each BS design with spikes (narrow, broad, and 4-prong) in a porcine knee model, whereas BSs without spikes led to failure of the fixation construct during cyclic loading in 4 of 10 specimens and increased elongation and lower ultimate failure loads in the remainder of the group. BSs without spikes may therefore not be recommended for graft fixation. Clinical Relevance: The use of BSs can help to avoid the conflict of converging tunnels in multiligament reconstruction surgery. An implant design with spikes yields significantly higher biomechanical stability than BSs without spikes.

In vivo strains at the middle and distal thirds of the tibia during exertional activities

There is a known variance in the incidence and anatomical site of tibial stress fractures among infantry recruits and athletes who train according to established uniform training programs. To better understand the biomechanical basis for this variance, we conducted in vivo axial strain measurements using instrumented bone staples affixed in the medial cortex, aligned along the long axis of the tibia at the level of the mid and distal third of the bone in four male subjects. Strain measurements were made during treadmill walking, treadmill running, drop jumps from a 45 cm height onto a force plate and serial vertical jumps on a force plate. Significance levels for the main effects of location, type of activity and their interaction were determined by quasi-parametric methodologies. Compared to walking, running and vertical jumping peak axial tensile strain (με) was 1.94 (p = 0.009) and 3.92 times (p < 0.001) higher, respectively. Peak axial compression strain (με) values were found to be greater at the distal third than at the mid tibia for walking, running and vertical jumping (PR = 1.95, p-value<0.001). Peak axial compression and tension strains varied significantly between the subjects (all with p < 0.001), after controlling for strain gauge location and activity type.The study findings help explain the variance in the anatomical location of tibial stress fractures among participants doing the same uniform training and offers evidence of individual biomechanical susceptibility to tibial stress fracture. The study data can provide guidance when developing a generalized finite element model for mechanical tibial loading. For subject specific decisions, individualized musculoskeletal finite element models may be necessary.

Biomechanical Analysis of Staples for Epiphysiodesis

Limb asymmetry can, and often does, cause various health problems. Blount bone staples (clips) are used to correct such uneven growth. This article analyzes the performance of a biomechanical staple during bone (tibia) growth arrest. The staples considered in this study were made of 1.4441 stainless steel, the model of tibia consisted of two materials representing corticalis and spongiosis. Hooke’s law was used for modeling materials’ behaviors for finite element analysis (FEA). The maxima of stress and total staple displacement were evaluated using the finite element method and verification of the results, along with the determination of the maximum loading (growing) force that the staples are capable of withstanding, was performed experimentally. The presented method can be used to determine the safety and usability of staples for bone growth arrest. According to our results, the design of Blount staples considered in this paper is safe and suitable for orthopedic treatment.

Isolated Bioinductive Arthroscopic Repair of Partial-Thickness Rotator Cuff Tears Using a Resorbable Collagen Implant.

A diagnostic arthroscopy is performed via a posterior viewing portal, paying particular attention to the insertion of the posterosuperior rotator cuff onto the humeral head. The subacromial space is entered posteriorly and visualized. With use of electrocautery through a lateral portal, all soft tissue is cleared from the undersurface of the acromion and from the superficial rotator cuff. The coracoacromial ligament is released from the underside of the acromion, and an acromioplasty is performed if indicated. The partial-thickness rotator cuff tear is visualized and examined for tissue quality, tear area, and residual tendon thickness. The size of the tear is measured, and an appropriate implant size is chosen. The lateral portal is enlarged so that the graft can be inserted and unfolded with use of a specialized delivery guide. The implant is centered over the tear, ensuring that it covers as much of the lateral footprint as possible. To complete the procedure, the implant is secured to the tendon with use of soft-tissue staples and to the lateral osseous footprint with use of bone staples. First-line treatment is often nonoperative and entails activity modification, pharmacological therapies, and targeted physiotherapy directed toward strengthening parascapular muscles and the remaining rotator cuff. Surgical treatment is considered for persistent symptoms. Conventional operative strategies include subacromial decompression, rotator cuff debridement, in situ repair, and conversion to a full-thickness defect and repair. Partial-thickness tears substantially increase intratendinous strain. This increased strain leads to further tissue degeneration and tear enlargement5, likely influencing the high rate of tear propagation observed with nonoperative treatment and nonanatomic operative treatment, such as subacromial decompression. Isolated bioinductive repair of partial-thickness tears with use of a resorbable collagen implant does not involve tendon excision or repair of the tendon to the bone, which can sometimes be challenging. This technique offers a simple solution to a complex problem and has the benefit of an accelerated rehabilitation program compared with formal rotator cuff repair. Accordingly, patient satisfaction with the procedure is high, making this treatment an appealing option4. Short and midterm results following isolated bioinductive repair of partial-thickness tears demonstrate that it is a safe procedure associated with a reduction in pain, increased range of motion, and improvement in functional outcomes. Patients should be counselled regarding the safety of a resorbable collagen patch and its potential to promote healing and improve symptoms4-6. If the tear is articular, it should be marked with a needle so that the graft can be centered over the tear within the subacromial space.When positioning the implant, ensure that it covers the defect and the lateral footprint.Position the cannulas so that they allow the staples to enter the tissue perpendicular to the tendon and osseous footprint.To prevent tearing of the patch, do not depress the staples with excessive force. MRI = magnetic resonance imagingPEEK = polyetheretherketoneVAS = visual analogue scaleASES = American Shoulder and Elbow Surgeons Shoulder Score.

Assessing the biomechanical properties of nitinol staples in normal, osteopenic and osteoporotic bone models: A finite element analysis

ObjectiveBone staples are internal fixation devices that are frequently used in the foot, ankle, and hand to provide stabilization. Fixation stability is vital after fusion or fracture surgeries to ensure proper bone healing. Patients undergoing surgeries that require fixation to keep bones aligned and stable may present with diminishing bone mechanical properties, and this may compromise the ability of the fixation hardware to maintain a stable construct. The purpose of this study was to investigate the mechanical performance of shape memory and superelastic nitinol bone staples with different bridge geometries in normal, osteopenic, and osteoporotic bone models. Contact forces and maximum principal stress and strain in the bone were recorded. MethodsFinite element simulations of a bone staple fixation procedure were performed to examine the initial and post-surgery contact force, as well as the maximum principal stress and strain of 15 mm bridge and 20 mm bridge staple-bone constructs. ResultsShape memory nitinol staples exhibited higher contact forces compared to superelastic nitinol staples. Nitinol bone staples with 20 mm bridge lengths displayed higher contact forces and lower stresses in all bone types, as well as lower strains in osteoporotic bone models compared to nitinol staples with a 15 mm bridge length. ConclusionNitinol bone staple constructs with 20 mm bridge length staples provide higher contact forces and display lower stresses in the bone than 15 mm bridge staple-bone constructs, which may be beneficial in bone with diminishing mechanical properties. Both superelastic and shape memory effect nitinol staples provide adequate compression and stress relief. However, if osteopenia is present, shape memory effect nitinol staples with a 20 mm bridge length may provide more stress relief and compression, if the bone anatomy allows.

Bone Staples Provide Favorable Primary Stability in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction: A Biomechanical Study.

Background:The use of the interference screw (IFS) for the cortical fixation of tendon grafts in knee ligament reconstruction may lead to converging tunnels in the multiligament reconstruction setting. It is unknown whether alternative techniques using modern suture anchor (SA) or bone staple (BS) fixation provide sufficient primary stability.Purpose:To assess the primary stability of cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction using modern SA and BS methods in comparison with IFS fixation.Study Design:Controlled laboratory study.Methods:Cortical tendon graft fixation was performed in a porcine knee model at the tibial insertion area of the MCL using 3 different techniques: IFS (n = 10), SA (n = 10), and BS (n = 10). Specimens were mounted in a materials testing machine, and cyclic loading for 1000 cycles at up to 100 N was applied to the tendon graft, followed by load-to-failure testing. Statistical analysis was performed using 1-way analysis of variance.Results:There were no statistical differences in elongation during cyclic loading or peak failure load during load-to-failure testing between BS (mean ± standard deviation: 3.4 ± 1.0 mm and 376 ± 120 N, respectively) and IFS fixation (3.9 ± 1.2 mm and 313 ± 99.5 N, respectively). SA fixation was found to have significantly more elongation during cyclic loading (6.4 ± 0.9 mm; P < .0001) compared with BS and IFS fixation and lower peak failure load during ultimate failure testing (228 ± 49.0 N; P < .01) compared with BS fixation.Conclusion:BS and IFS fixation provided comparable primary stability in the cortical fixation of tendon grafts in MCL reconstruction, whereas a single SA fixation led to increased elongation with physiologic loads. However, load to failure of all 3 fixation techniques exceeded the loads expected to occur in the native MCL.Clinical Relevance:The use of BS as a reliable alternative to IFS fixation for peripheral ligament reconstruction in knee surgery can help to avoid the conflict of converging tunnels.

Hemiepiphysiodesis via the Bowen Method for Genu Valgum in Adolescents

Surgical techniques using bone blocks, screws, plates and staples have been described to biologically manipulate the growth plate to correct leg length inequality, genu varum and genu valgum.

An approach for material selection for bone staple (an orthopaedic implant) using GRA and Fuzzy logic

Abstract This paper aims to develop a mathematical framework to compare suitability of multiple candidate biomaterials for the manufacture of bone staples. This task is essentially a materials selection problem. Multiple criteria have been considered for evaluation which are numerical parameters related to Biocompatibilty, Mechanical properties and Manufacturing feasibility. A comparison has been done for the selection results obtained by two optimisation methods: Gray relational analysis (GRA) and Fuzzy logic. The three candidate materials chosen are SS316L, Ti6Al4V and Nitinol. GRA gives Ti6Al4V as the most suitable material while Fuzzy logic gives Nitinol as the most suitable material. This material selection approach can serve as an effective starting point for further investigation into these types of problems.

A Ni-free β-Ti alloy with large and stable room temperature super-elasticity

A Ni-free β-Ti alloy comprising Ti-40Hf-13Nb-4.5Sn (wt.%) was developed as a substitute for NiTi (nitinol) alloys in medical applications. It is found that, due to significant Stress Induced Martensite (SIM) transformation and large lattice transformation strain, combined with good strength and stability, this alloy showed large and stable super-elastic deformation behavior at room temperature. Total recoverable strain of 5.3 % was obtained at 6% deformation. According to preliminary data, mechanical properties and fatigue performance of this alloy are within the neighborhood of super-elastic NiTi alloys. Plateau strengths can be further tuned to a wide range by low temperature aging similar to Ni-rich binary NiTi. It can be manufactured in large industrial scales by commercial production lines, has been melted in hundreds of kilogram scale, and is relatively easy to shape set into device subcomponent forms. With additional characteristics such as relatively high X-ray visibility, good corrosion resistance and biocompatibility, this alloy provides a superelastic option in Ni-sensitive dental, orthodontic, orthopedic bone staple, and neurovascular applications to name a few possibilities.

The Influence of Severe Plastic Deformation on Microstructure and In Vitro Biocompatibility of the New Ti-Nb-Zr-Ta-Fe-O Alloy Composition.

In this work, severe plastic deformation (SPD) of the newly designed Ti-Nb-Zr-Ta-Fe-O GUM metal was successfully conducted at room temperature using high speed high pressure torsion (HSHPT) followed by cold rolling (CR) to exploit the suitability of the processed alloy for bone staples. The Ti-31.5Nb-3.1Zr-3.1Ta-0.9Fe-0.16O GUM alloy was fabricated in a levitation melting furnace using a cold crucible and argon protective atmosphere. The as-cast specimens were subjected to SPD, specifically HSHPT, and then processed by the CR method to take the advantages of both grain refinement and larger dimensions. This approach creates the opportunity to obtain temporary orthopedic implants nanostructured by SPD. The changes induced by HSHPT technology from the coarse dendrite directly into the ultrafine grained structure were examined by optical microscopy, scanning electron microscopy and X-ray diffraction. The structural investigations showed that by increasing the deformation, a high density of grain boundaries is accumulated, leading gradually to fine grain size. In addition, the in vitro biocompatibility studies were conducted in parallel on the GUM alloy specimens in the as-cast state, and after HSHPT- and HSHPT+CR- processing. For comparative purposes, in vitro behavior of the bone-derived MC3T3-E1 cells on the commercially pure titanium has also been investigated regarding the viability and proliferation, morphology and osteogenic differentiation. The results obtained support the appropriateness of the HSHPT technology for developing compression staples able to ensure a better fixation of bone fragments.

Three dimensional finite element modelling of metatarsal stresses during running

Second metatarsal stress fractures are a problematic injury for runners and are formed when the rate of repair of bone is outpaced by the damage accumulated during loading. Measuring the peak stresses on the bone during running gives an indication of damage accumulation but direct measurement is invasive. Finite element modelling is a viable alternative method of accurately estimating bone stresses but tends to be too computationally expensive for use in applied research. This study presents a novel and simple finite element model which can estimate bone stresses on the second metatarsal during the stance phase of walking and running, accounting for joint reaction forces and soft tissue effects. The influence of the forces and kinematic inputs to the model and the presence of the soft tissues was quantified using a sensitivity analysis. The magnitudes of maximum stress from the model are similar to existing finite element models and bone staple strain gauge values collected during walking and running. The model was found to be most sensitive to the pitch angle of the metatarsal and the joint reaction forces and was less sensitive to the ground reaction forces under the metatarsal head, suggesting that direct measurement of external forces should not be assumed to represent internal stresses.

Effects on Microstructure and Material Properties for TiNiCo Shape Memory Alloy

Wire spark discharge machining of TiNiCo alloys for bone staple applications is presented. A vacuum arc melting furnace was used to develop TiNiCo alloys with varied cobalt (Co) contents (1, 5 and ...

CORR Synthesis: Can Guided Growth for Angular Deformity Correction Be Applied to Management of Pediatric Patellofemoral Instability?

CORR Synthesis: Can Guided Growth for Angular Deformity Correction Be Applied to Management of Pediatric Patellofemoral Instability?

Wire electro spark machining and characterization studies on Ti50Ni49Co1, Ti50Ni45Co5 and Ti50Ni40Co10 alloys

The wire electrical discharge machining process (WEDM) is high demand and influenced by various input process parameters namely pulse duration, voltage, wire diameters and wire material. In this research, a smart material made of TiNiCo alloy is investigated to study the machinability using WEDM process. The pulse duration and servo voltage varied to perform the experiments on Ti50Ni49Co1 Ti50Ni45Co5 and Ti50Ni40Co10 smart materials for bone staple applications which were designed by ELCAM software and generated G-code for machining with same software. L-25 orthogonal array used for machining of selected alloys, which is created (L-25 orthogonal array) through Taguchi design of experiment. From the experiments, an analysis was made to study the amount of material removal and average roughness as a response. Further machined areas were subjected to metallurgical characterization techniques such as surface topography, EDS analysis, residual stress calculation and wear mechanism. Tensile residual stress was noticed at higher values of outputs while lower values of residual stress at lower values of outputs which were also confirmed through microstructure and surface topography that smoother surface has been found at lower values of outputs. Moreover, the higher value of residual stress has been noticed on the machined surface of Ti50Ni40Co10 alloy while lower on the machined surface of Ti50Ni49Co1 alloy. Copper (Cu), Zinc (Zn), Carbon (C) and Oxygen (O) were found as additional elements on the machined surface during the EDS analysis of machined components for each alloy.

Role of constraining staple on tibial slope in open wedge osteotomy: A comparative study

BackgroundMedial opening-wedge high tibial osteotomy (HTO) corrects varum deformities in osteoarthritic knees. This procedure has been shown to increase tibial slope, which may limit knee extension and provoke an anterior tibial translation. The purpose of this research was to study the impact of a constraining staple on the variation of the tibial slope in medial opening-wedge HTO. HypothesisInsertion of a bone staple on the anterior aspect of the tibia during medial opening-wedge HTO minimizes risks of tibial slope increase. Materials and methodsThis retrospective study was conducted on 91 cases of HTO performed by a single surgeon between 2008 and 2013. Tibial slope was measured pre-operatively and postoperatively according to Brazier's method. We analyzed tibial slope variation in a group that did not receive bone staple insertion during their HTO and compared to the group that did. ResultsA total of 91 patients met the inclusion criteria, 61 males (67.0%) and 30 females (33.0%). The median age was 51 years old. In the staple group, a 0.1° mean increase in tibial slope was found (p<0.001), whereas in the non-staple-inserted group, a 2.4° mean increase in tibial slope was observed (p<0.001). Discussion and conclusionThe use of a temporary anterior staple during medial-opening HTO appears to be effective in minimizing tibial slope increase. Level of evidenceIII, Retrospective comparative study.

Results of percutaneous hemiepiphysiodesis in adolescents with idiopathic genu valgum

Purpose: Multiple surgical techniques using bone blocks, screws, plates, and staples have been described to biologically manipulate the growth plate to correct leg length inequality, genu varum, and genu valgum. Genu valgum is part of a normal physiologic process in children, but when excessive can lead to detrimental alterations in gait and lower extremity alignment in adolescence. This study evaluated the outcomes of percutaneous hemiepiphysiodesis, as described by Bowen in 1984, in adolescents with idiopathic genu valgum. Methods: An IRB-approved retrospective review was …