Stimulate Bone Healing Research Articles

Bortezomib-releasing silica-collagen xerogels for local treatment of osteolytic bone- and minimal residual disease in multiple myeloma

BackgroundAccumulation of malignant plasma cells in the bone marrow causes lytic bone lesions in 80% of multiple myeloma patients. Frequently fracturing, they are challenging to treat surgically. Myeloma cells surviving treatment in the presumably protective environment of bone lesions impede their healing by continued impact on bone turnover and can explain regular progression of patients without detectable minimal residual disease (MRD). Locally applicable biomaterials could stabilize and foster healing of bone defects, simultaneously delivering anti-cancer compounds at systemically intolerable concentrations, overcoming drug resistance.MethodsWe developed silica-collagen xerogels (sicXer) and bortezomib-releasing silica-collagen xerogels (boXer) for local treatment of osteolytic bone disease and MRD. In vitro and in vivo (tissue sections) release of bortezomib was assessed by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Material impact on bone formation was assessed in vitro regarding osteoclast/osteoblast numbers and activity. In vivo, drilling defects in a rat- and the 5T33-myeloma mouse model were treated by both materials and assessed by immunohistochemistry, UPLC-MS/MS, µCT, and ToF-SIMS. The material’s anti-myeloma activity was assessed using ten human myeloma cell lines (HMCLs) and eight primary myeloma cell samples including four patients refractory to systemic bortezomib treatment.ResultssicXer and boXer show primary stability comparable to trabecular bone. Granule size and preparation method tailor degradation as indicated by release of the xerogel components (silica and collagen) and bortezomib into culture medium. In vitro, both materials reduce osteoclast activity and do not negatively interfere with osteoblast differentiation and function. The presumed resulting net bone formation with maintained basic remodeling properties was validated in vivo in a rat bone defect model, showing significantly enhanced bone formation for boXer compared to non-treated defects. Both materials induce myeloma cell apoptosis in all HMCLs and primary myeloma cell samples. In the 5T33-myeloma mouse model, both materials stabilized drilling defects and locally controlled malignant plasma cell growth.ConclusionsThe combination of stabilization of fracture-prone lesions, stimulation of bone healing, and anti-tumor effect suggest clinical testing of sicXer and boXer as part of a combined systemic/local treatment strategy in multiple myeloma and non-malignant diseases.

Local Delivery of Melatonin Along With Bone Grafts to Improve Osteogenesis

This review is an attempt to investigate the effects of local delivery of melatonin along with bone grafts to improve osteogenesis. A systematic literature search was done from January 1970 to December 2023 using PubMed following PRISMA instructions. A structured search was carried out to identify in vivo and in vitro studies. After screening the articles based on the abstract and title, 24 articles were included. The included studies were animal/human in vivo studies or in vitro studies. In total, 91.7% of the studies reported better outcomes in comparison with the control groups. Melatonin potentially can affect many signaling molecules and pathways promoting osteoblastic differentiation, such as activating pathways including Wnt, Nrf2/HO-1, PI3K/AKT, MAPK, NFkB, SIRT/SOD, BMP/Smad, PERK/ATF4. In conclusion, locally administered melatonin may stimulate bone healing in surgical bone defects and enhance peri-implant bone response.

Supplemental Magnesium Gluconate Enhances Scaffold-Mediated New Bone Formation and Natural Bone Healing by Angiogenic- and Wnt Signal-Associated Osteogenic Activation.

Local implantation or supplementation of magnesium gluconate (MgG) is being investigated as an effective approach to bone repair. Although studies have highlighted the possible mechanisms in Mg ion-stimulated new bone formation, the role of MgG in healing bone defects and the signaling mechanisms are not yet completely understood. In this study, we explored how supplemental MgG has bone-specific beneficial effects by delivering MgG locally and orally in animal models. We fabricated MgG-incorporated (CMC-M) and -free chitosan (CMC) scaffolds with good microstructures and biocompatible properties. Implantation with CMC-M enhanced bone healing in rat model of mandible defects, compared with CMC, by activating Wnt signals and Wnt-related osteogenic and angiogenic molecules. Oral supplementation with MgG also stimulated bone healing in mouse model of femoral defects along with the increases in Wnt3a and angiogenic and osteogenic factors. Supplemental MgG did not alter nature bone accrual and bone marrow (BM) microenvironment in adult mouse model, but enhanced the functioning of BM stromal cells (BMSCs). Furthermore, MgG directly stimulated the induction of Wnt signaling-, angiogenesis-, and osteogenesis-related molecules in cultures of BMSCs, as well as triggered the migration of endothelial cells. These results suggest that supplemental MgG improves bone repair in a way that is synergistically enhanced by Wnt signal-associated angiogenic and osteogenic molecules. Overall, this study indicates that supplemental MgG might ameliorate oxidative damage in the BM, improve the functionality of BM stem cells, and maintain BM-microenvironmental homeostasis.

Functional Outcome of Extra-Articular Distal Tibia Fracture Treated with Tibia Interlocking Nail: A Case Series

Background: Intramedullary interlocking nailing has emerged as one of the suitable management options for distal tibia fractures as it allows mechanical compression on weight-bearing, which stimulates bone healing. We studied 40 cases of extra-articular distal tibia fracture treated by intramedullary nailing. Methods: We retrospectively studied 40 patients of both sexes above the age of 18 years with closed fractures and grade 1, 2, and 3A compound fractures treated at SVP Hospital, Ahmedabad, India. Clinically, the fracture was considered to be united when the patient was completely pain-free. Patients were followed up at monthly intervals till union. At each follow-up, patients were assessed both clinically and radiographically, and details were recorded based on proforma. Results: The evaluation of the result was done using American Orthopedic Foot and Ankle Society (AOFAS) criteria. Thirty-three patients had excellent functional results, five had good functional results, and Two had fair functional results. In this study, 38 (95%) patients had radiological union within 24 weeks. Two patients had union after 28 weeks. Conclusion: Intramedullary nailing is a minimally invasive procedure that preserves the soft tissue and the fracture hematoma. It maintains the length, alignment, and rotation and allows micromotion at the fracture site on weight-bearing, which stimulates callus formation. It has a good functional outcome with gratifying results when used in extra-articular distal tibia fractures.

Biomechanical study of three-dimensional printed filler block design in open wedge high tibial osteotomy

The use of a filling block can improve the initial stability of the fixation plate in the open wedge high tibial osteotomy (OWHTO), and promote bone healing. However, the biomechanical effects of filling block structures and materials on OWHTO remain unclear. OWHTO anatomical filling block model was designed and built. The finite element analysis method was adopted to study the influence of six filling block structure designs and four different materials on the stress of the fixed plate, tibia, screw, and filling block, and the micro-displacement at the wedge gap of the OWHTO fixation system. After the filling block was introduced in the OWHTO, the maximum von Mises stress of the fixation plate was reduced by more than 30%, the maximum von Mises stress of the tibia decreased by more than 15%, and the lateral hinge decreased by 81%. When the filling block was designed to be filled in the posterior position of the wedge gap, the maximum von Mises stress of the fixation system was 97.8 MPa, which was smaller than other filling methods. The minimum micro-displacement of osteotomy space was -2.9 μm, which was larger than that of other filling methods. Compared with titanium alloy and tantalum metal materials, porous hydroxyapatite material could obtain larger micro-displacement in the osteotomy cavity, which is conducive to stimulating bone healing. The results demonstrate that OWHTO with a filling block can better balance the stress distribution of the fixation system, and a better fixation effect can be obtained by using a filling block filled in the posterior position. Porous HA used as the material of the filling block can obtain a better bone healing effect.

Subchondral cystic lesions of distal phalanx in young and mature horses: A new surgical option

SummaryBackgroundThe outcome of conservative treatment for subchondral cystic lesions (SCLs) of the distal phalanx may be poor, and surgical approach through the hoof may be challenging.ObjectivesTo describe the use of an absorbable device to treat SCLs of the distal phalanx, regardless of cyst location, that eliminates lameness and stimulates bone healing in both young and mature horses.Study designClinical case series.MethodsFive young horses and five mature horses presented with an SCL of the distal phalanx causing lameness. Only rest and medical treatment were previously attempted. An absorbable screw was inserted in all horses after transcortical debridement of the SCL. Follow‐up data were obtained from the official electronic database.ResultsAll horses returned to athletic activity after surgical treatment. In two patients, surgical complication was recorded.Main limitationsThe low number of patients, the need for dedicated instruments and the lack of familiarity with the use of absorbable devices to perform surgical procedures.ConclusionsThe insertion of an absorbable device can be considered a valid surgical option for treating subchondral cystic lesions of the distal phalanx.

Management of open fracture and related complications: the Japanese way.

Open fractures continue to be a challenging clinical problem throughout the world, and Japan is no exception. Surgeons are faced with critical decisions throughout the care of these injuries that can have significant effects in clinical outcome, ranging from the type and timing of antibiotic administration, fixation, soft-tissue management, and interventions for postfracture complications. In October 2022, the Japanese Society for Fracture Repair (JSFR) was invited to represent Japan as the Guest Nation society at the 38th Annual Meeting of the Orthopaedic Trauma Society held in Tampa, Florida. The JSFR organized a symposium, entitled "Management of Open Fracture and related complications-the Japanese way," that featured cutting-edge approaches to open fractures in their country, including presentations on the "fix-and-flap" approach, local antibiotics perfusion delivery, and a "chipping" method for the stimulation of bone healing. This article summarizes the content of these 3 presentations from that symposium.

Low Intensity Renal Ultrasound Exposure Reduces Systemic Inflammation Induced by LPS Challenge in Mice

Low-intensity pulsed ultrasound (LIPUS), a procedure historically used to stimulate bone healing and tissue repair, activates the splenic cholinergic anti-inflammatory pathway and ultimately reduces circulating and tissue-specific pro-inflammatory cytokine release if applied to the kidney prior to renal ischemia/reperfusion injury. We questioned whether LIPUS would be effective in reducing the inflammatory response to lipopolysaccharide (LPS) if exposure occurred as pre- or post-treatment. We hypothesized that LIPUS exposure before an LPS challenge would suppress the subsequent inflammatory response in mice, and that LIPUS exposure after an LPS challenge would be similarly beneficial. Female C57BL/6J mice were randomized into Saline, LPS, LPS/Pre-treatment and LPS/Post-treatment groups at 15 weeks of age. Pre-treated mice were subjected to 20-minute LIPUS exposure while under anesthesia for five consecutive days. On the 6th day, mice were injected with LPS (1 mg/kg dissolved in saline, IP) or saline (100 μL). One hour after LPS injection, post-treated mice were exposed to LIPUS for 20 min. Three hours after LPS or saline injection, all mice were humanely euthanized, and plasma, spleen and kidney were harvested for analysis of proinflammatory cytokines associated with the response to LPS. LPS significantly increased plasma TNF-α (280±37 vs. 0.07±0.00 pg/mL), plasma IL-6 (96124±6688 vs. 425±181 pg/mL), splenic IL-6 (0.77±0.16 vs. 0.17±0.04 pg/μg of protein), and renal cortical IL-6 (0.50±0.07 vs. 0.01±0.00 pg/μg of protein) compared to saline-treated mice (all p<0.05). LIPUS pre-treatment significantly reduced plasma TNF-α (183±15 pg/mL) and plasma IL-6 (63656±8441 pg/mL), without altering splenic and renal cytokines in LPS-treated mice. LIPUS post-treatment lowered plasma IL-6 (47432 ± 1182 pg/mL). In conclusion, five days of LIPUS exposure prior to an LPS challenge effectively reduced circulating inflammatory mediators, while a single LIPUS exposure after an LPS challenge also successfully reduced systemic IL-6. These findings demonstrate the potential in using LIPUS as a therapeutic strategy for quelling acute inflammatory responses and warrant further investigation of its use as a therapy for chronic inflammatory diseases. Studies funded by Department of Defense (LR210096) for KWM. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Comparative Analysis of Stromal Vascular Fraction and Alternative Mechanisms in Bone Fracture Stimulation to Bridge the Gap between Nature and Technological Advancement: A Systematic Review.

Various stimulation methods, including electrical, ultrasound, mechanical, and biological interventions, are explored, each leveraging intricate cellular and molecular dynamics to expedite healing. The advent of stromal vascular fraction (SVF) marks a significant stride, offering multifarious benefits in bone healing, from enhanced bone formation to optimal vascular integration, drawing a harmonious balance between innate mechanisms and scientific advancements. This systematic review was conducted focusing on literature from 2016 to 2023 and encompassing various bone healing stimulation mechanisms like SVF, electrical, ultrasound, and mechanical stimulation. The extracted data underwent meticulous synthesis and analysis, emphasizing comparative evaluations of mechanisms, applications, and outcomes of each intervention. The reviewed studies reveal the potential of SVF in bone fracture healing, with its regenerative and anti-inflammatory effects. The purification of SVF is crucial for safe therapeutic use. Characterization involves flow cytometry and microscopy. Studies show SVF's efficacy in bone regeneration, versatility in various contexts, and potential for clinical use. SVF appears superior to electrical, ultrasound, and mechanical stimulation, with low complications. This review compares bone healing methods, including SVF. It provides valuable insights into SVF's potential for bone regeneration. However, due to limited human studies and potential bias, cautious interpretation is necessary. Further research is essential to validate these findings and determine the optimal SVF applications in bone healing.

Orthodontic management of a developing dentigerous cyst related to lower second molar: a case report

The dentigerous cyst is a developmental odontogenic asymptomatic cyst, that is associated with the crown of an unerupted or impacted tooth. Early diagnosis is important to avoid any future complications and choose the best treatment option. The purpose of this case report is to describe the management of a dentigerous cyst related to lower second molar in a young female patient using orthodontic traction as a conservative treatment approach. This procedure helps to spare the patient an unnecessary surgical excision procedure and the associated excessive bone removal for a safety margin, stimulates bone healing and promotes the eruption of the cyst-associated tooth.

First Clinical Case of Ilizarov Femur Lengthening over a Bioactive and Degradable Intramedullary Implant

Introduction. The Ilizarov distraction osteogenesis is a recognized method of limb lengthening in orthopaedic practice. Its most challenging problems are long duration of external fixation and related pin-tract infection and joint contractures. The solution might be the use of a bioactive degradable intramedullary implant stimulating bone healing. Case Presentation. We present a case of a 14-year-old boy with 6 cm posttraumatic shortening of the femur and associated varus deformity of 20 degrees. He was treated with the Ilizarov technique of femur lengthening over an intramedullary degradable polycaprolactone (PCL) implant with hydroxyapatite (HA) filling. We faced no complications within the lengthening process. Shortening and deformity of the femur were corrected in 90 days. The index of external fixation was 15 days/cm. External fixation time was reduced almost twice comparing to the conventional method. Degradable intramedullary nails ensured the advantage of avoidance of the removal procedure. Radiography and CT confirmed faster new bone healing and remodeling. Conclusion. The combined lengthening technique over a PCL/HA implant might be used to shorten external fixation time and to stimulate bone healing especially in patients with compromised bone. Using a bioabsorbable material presents the benefit of eliminating the need for a second surgery to remove the nail, thereby reducing soft tissue damage.

The effect of bone remodeling with photobiomodulation in dentistry: a review study.

Photobiomodulation (PBM) has been emerging as a promising alternative therapy in dentistry. However, various parameters of PBM are used in different studies, and there is limited cumulative data on PBM for improving bone formation in clinical trials. The aim of this review was to evaluate the effectiveness of PBM in the process of bone remodeling in dentistry using randomized controlled trials. Initially, a total of 1,011 articles published from January 2008 to December 2021 were retrieved from five electronic databases (PubMed, Scopus, Cochrane Library, EMBASE, and CINAHL). After a two-step review, nine articles met the inclusion criteria. The parameter of PBM, group, treatment sessions, assessment times and outcomes of the included studies were reviewed. Eighty-nine percent of the studies revealed positive effects on bone formation between the laser group and the control group. Only one article reported that light-emitting diode did not significantly enhance osteogenesis. Additionally, the present study shows that Gallium aluminum arsenide of near infrared (NIR) laser with continuous mode is the most commonly used form of PBM. The biostimulatory effects are dependent on several parameters, with wavelength and dose being more important than others. Based on this review, it is suggested that the NIR range and an appropriate dose of PBM could be used to increase the efficiency of stimulating bone healing and remodeling. However, standardization of treatment protocols is needed to clarify therapeutic strategies in dentistry.

Biodegradable biomaterials in orthopedic surgery: A narrative review of the current evidence.

Biomaterials are routinely used in orthopedic surgery to fill bone defects, improve bone healing, and as degradable fixation material. A wide range of materials are currently in use, and the materials are chosen according to their bioactive properties. Osteoinductive materials stimulate bone healing by promoting osteogenesis. Osteoconductive materials facilitate bone growth on the surface of the material. Despite the many materials in use and an increasing number of published studies, randomized controlled trials on the subject are scarce. This review aims to summarize the history of biodegradable biomaterials and also the published level I evidence currently available on orthopedic biomaterials. Most of the studies have been superiority trials with non-significant differences compared to conventional treatment options, confirming that several biomaterials are suitable treatment options for multiple indications including bone and/or tendon fixation, filling bone defects, and spinal fusion. Biomaterials help to avoid donor site complications associated with autogenous bone grafts and often eliminate the need for implant removal. However, the surgical technique may in some cases be more demanding than with conventional methods. Careful consideration of the pros and cons is therefore recommended in clinical practice. Biodegradable biomaterials complement the range of available treatment options in several fields of orthopedic surgery. However, some biomaterials performed worse than expected and were not recommended for clinical use, emphasizing the need for high-quality randomized trials. It is also noteworthy that several trials included only a limited number of patients, rendering the interpretation of the results of these underpowered studies challenging.

Simulation of ultrasonically induced electrical potentials in bone.

Low-intensity pulsed ultrasound treatment is known to shorten the healing period of bone fractures by 30%-40%, but the initial mechanism of the healing process remains unknown. One possible mechanism is related to the piezoelectricity of bone. However, the complex geometry of bones results in inherent challenges to evaluating electric fields induced therein. Therefore, in this study, we investigate the piezoelectric responses of bones by using simulations to study the wave propagation and induced potentials in bone, according to the piezoelectric finite-difference time-domain (PE-FDTD) method. First, we verify the suitability of the PE-FDTD method by comparing the simulated electric field results with the experimental data obtained by an ultrasound receiver using bone as the piezoelectric element. Next, ultrasound irradiation into a real bone model (the radius of a 66-year-old woman) is simulated at different incident angles. At normal incidence and off-axis incidence (45°), the maximum electric field strength was 4.3 and 5.6 mV/cm, respectively. We also present evidence of significant shear wave contribution to the induced potential. The results of this study confirm the existence of ultrasonically induced potentials in heterogenous bones with complex shapes, equal in magnitude to potentials generated in electrically stimulated bone healing.

Encapsulation of β-NGF in injectable microrods for localized delivery accelerates endochondral fracture repair.

Introduction: Currently, there are no non-surgical FDA-approved biological approaches to accelerate fracture repair. Injectable therapies designed to stimulate bone healing represent an exciting alternative to surgically implanted biologics, however, the translation of effective osteoinductive therapies remains challenging due to the need for safe and effective drug delivery. Hydrogel-based microparticle platforms may be a clinically relevant solution to create controlled and localized drug delivery to treat bone fractures. Here, we describe poly (ethylene glycol) dimethacrylate (PEGDMA)-based microparticles, in the shape of microrods, loaded with beta nerve growth factor (β-NGF) for the purpose of promoting fracture repair. Methods: Herein, PEGDMA microrods were fabricated through photolithography. PEGDMA microrods were loaded with β-NGF and in vitro release was examined. Subsequently, bioactivity assays were evaluated in vitro using the TF-1 tyrosine receptor kinase A (Trk-A) expressing cell line. Finally, in vivo studies using our well-established murine tibia fracture model were performed and a single injection of the β-NGF loaded PEGDMA microrods, non-loaded PEGDMA microrods, or soluble β-NGF was administered to assess the extent of fracture healing using Micro-computed tomography (µCT) and histomorphometry. Results: In vitro release studies showed there is significant retention of protein within the polymer matrix over 168 hours through physiochemical interactions. Bioactivity of protein post-loading was confirmed with the TF-1 cell line. In vivo studies using our murine tibia fracture model show that PEGDMA microrods injected at the site of fracture remained adjacent to the callus for over 7 days. Importantly, a single injection of β-NGF loaded PEGDMA microrods resulted in improved fracture healing as indicated by a significant increase in the percent bone in the fracture callus, trabecular connective density, and bone mineral density relative to soluble β-NGF control indicating improved drug retention within the tissue. The concomitant decrease in cartilage fraction supports our prior work showing that β-NGF promotes endochondral conversion of cartilage to bone to accelerate healing. Discussion: We demonstrate a novel and translational method wherein β-NGF can be encapsulated within PEGDMA microrods for local delivery and that β-NGF bioactivity is maintained resulting in improved bone fracture repair.

What's New in Musculoskeletal Basic Science.

What's New in Musculoskeletal Basic Science.

Optimal design and biomechanical analysis of sandwich composite metal locking screws for far cortical locking constructs.

In the interests of more flexible and less stiff bridge constructs to stimulate bone healing, the technique of far cortical locking has been designed to improve locked plating constructs in terms of stress concentration, stress shielding, and inhibition of issues around fracture healing. However, far cortical locking screws currently lack objective designs and anti-fatigue designs. This study investigates an optimization algorithm to form a special locking screw composed of various metals, which can theoretically achieve the maintenance of the excellent mechanical properties of far cortical locking constructs in terms of fracture internal fixation, while maintaining the biomechanical safety and fatigue resistance of the structure. The numerical results of our study indicate that the maximum von Mises stress of the optimized construct is less than the allowable stress of the material under each working condition while still achieving sufficient parallel interfragmentary motion. Numerical analysis of high cycle fatigue indicates that the optimized construct increases the safety factor to five. A high cycle fatigue test and defect analysis indicates that the sandwich locking constructs have better fatigue resistance. We conclude that the sandwich locking construct theoretically maintains its biomechanical safety and fatigue resistance while also maintaining excellent mechanical properties for fracture internal fixation.

Mechanisms of bone remodeling and therapeutic strategies in chronic apical periodontitis.

Chronic periapical periodontitis (CAP) is a typical oral disease in which periodontal inflammation caused by an odontogenic infection eventually leads to bone loss. Uncontrolled infections often lead to extensive bone loss around the root tip, which ultimately leads to tooth loss. The main clinical issue in the treatment of periapical periodontitis is the repair of jawbone defects, and infection control is the first priority. However, the oral cavity is an open environment, and the distribution of microorganisms through the mouth in jawbone defects is inevitable. The subversion of host cell metabolism by oral microorganisms initiates disease. The presence of microorganisms stimulates a series of immune responses, which in turn stimulates bone healing. Given the above background, we intended to examine the paradoxes and connections between microorganisms and jaw defect repair in anticipation of new ideas for jaw defect repair. To this end, we reviewed the microbial factors, human signaling pathways, immune cells, and cytokines involved in the development of CAP, as well as concentrated growth factor (CGF) and stem cells in bone defect repair, with the aim of understanding the impact of microbial factors on host cell metabolism to inform the etiology and clinical management of CAP.

Percutaneous Femoral Derotational Osteotomy in the Skeletally Immature Patient.

This is a percutaneous procedure that involves creation of femoral drill holes at the osteotomy site prior to reaming the canal4. External fixator pins are placed proximal and distal to the osteotomy site prior to completing the osteotomy. These pins are derotational markers for the surgeon and act to hold the correction with use of an external fixator while the interlocking screws are being placed. The pins are placed at a degree of divergence that is equal to the degree of intended derotation so that the pins will become parallel in the axial plane following derotation of the femur. The percutaneous osteotomy is then completed with use of an osteotome, and the trochanteric entry nail is passed across the osteotomy site while correcting rotation. Once rotation is fully corrected and the pins are parallel, the external fixator is placed to hold the rotation and interlocking screws are placed. Nonoperative alternatives to this procedure include physical therapy for gait training and strengthening as well as modalities to address hip and knee pain that may be associated with version abnormalities. Although physical therapy is often prescribed, it must be noted that excess version is a fixed osseous structural pathology that therapy cannot address. Additionally, compensatory mechanisms that may be taught to improve gait and walk with a neutral foot progression angle may exacerbate hip or knee pathology as a result of the underlying version abnormality. Surgical alternatives include derotational osteotomies of the proximal or distal aspects of the femur with use of an open technique with plate fixation, as opposed to an intramedullary nail following percutaneous diaphyseal osteotomy as presented here1. Additionally, an open technique with intramedullary nail fixation may be performed5. Excessive anteversion can cause both hip and knee symptoms, including hip pain, instability, labral and psoas pathology, and patellofemoral instability6. Excessive retroversion can cause impingement between the femoral neck and acetabulum, which results in pathology of the labrum and articular cartilage7. Additionally, abnormalities of version often lead to gait disturbances with frequent tripping and difficulty running8. Children with femoral version abnormalities have limited remodeling potential after age 83. A derotational osteotomy may be performed to correct symptomatic excess femoral version in an older child or adolescent. The patient may be weight-bearing as tolerated with upper-extremity assistance immediately following the procedure. The osteotomy typically heals between 6 and 12 weeks, and the patient may return to activities as tolerated once the osteotomy is healed. Gordon et al. described the outcomes of a similar technique for femoral derotational osteotomy in skeletally immature patients with excessive femoral anteversion3. The study retrospectively reviewed the results of the technique in 13 patients and 21 limbs at a minimum follow-up of 1 year. All patients complained of tripping and gait abnormalities preoperatively. All patients noted gait improvement, and no intraoperative or postoperative complications were reported. Healing of the osteotomy occurred at a mean of 6 weeks postoperatively. No patient developed osteonecrosis. We routinely remove hardware in skeletally immature patients approximately 1 year postoperatively. Complications are rare and include hardware irritation, infection, nonunion, and neurovascular injury. Preoperative planning is critical for this procedure, and the surgeon should know the intended degree of derotation, the location of the osteotomy relative to the greater trochanter, the length of the nail, and the approximate diameter of the nail prior to entering the operating room.Percutaneous bicortical femoral drill holes are created at the site of the osteotomy prior to reaming to allow for egress of reamings and bone marrow elements at the osteotomy site, which serve as autograft and stimulate bone healing. Additionally, the drill holes provide ventilation to prevent excessive intramedullary pressure during reaming9-11.External fixator pins are placed proximal and distal to the osteotomy prior to completion of the osteotomy to allow for rotational assessment after completion of the osteotomy. Placing these pins bicortically so that they are secure in the bone and ensuring that the divergence is correct for the intended amount of derotation is critical in this procedure because once the osteotomy is complete, the pins are the only markers of rotation the surgeon has to guide the correction.An external fixator is helpful in holding the femur at the intended degree of derotation during placement of the interlocking screws. ROM = range of motionCT = computed tomographyMRI = magnetic resonance imagingAP = anteroposteriorGT = greater trochanterAV = anteversionER = external rotationIR = internal rotationA = anteriorP = posteriorM = medialL = lateralXR = X-rayProx = proximalEx fix = external fixatorWBAT = weight-bearing as toleratedBLE = bilateral lower extremitiesDVT = deep venous thrombosisPT = physical therapyppx = prophylaxisAVN = avascular necrosis (osteonecrosis).

Design considerations for piezocomposite materials for electrical stimulation in medical implants

Incidence of non-union following long bone fracture fixation and spinal fusion procedures is increasing, and very costly for patients and the medical system. Direct current (DC) electrical stimulation has shown success as an adjunct therapy to stimulate bone healing and increase surgery success rates, though drawbacks of current devices and implantable battery packs have limited widespread use. Energy harvesting utilising piezoelectric materials has been widely studied for powering devices without a battery, and a preclinical animal study has shown efficacy of a piezocomposite spinal fusion implant resulting in faster, more robust fusion. Most piezoelectric energy harvesters operate most effectively at high frequencies, limiting power generation from loads experienced by orthopaedic implants during human motion. This work characterises the efficient power generation capability of a novel composite piezoelectric material under simulated walking loads. Building on compliant layer adaptive composite stacks (CLACS), the power generation of mixed-mode CLACS (MMCLACS) is defined. Utilising poling direction to capitalise on in-plane strain generation due to compliant layer expansion, MMCLACS significantly increased power output compared to a standard piezo stack. The combination of radial and through-thickness poled piezoelectric elements within a stack to create MMCLACS significantly increases power generation under low-frequency dynamic loads. This technology can be adapted to a variety of architectures and assembled as a load-bearing energy harvester within current implants. MMCLACS integrated with implants would provide enough power to deliver bone healing electrical stimulation directly to the fusion site, decreasing non-union rates, and also could provide quantitative assessment of healing progression through load sensing.