Aims. This study examined whether systemic administration of melatonin would have different effects on osseointegration in ovariectomized (OVX) rats, depending on whether this was administered during the day or night. Methods. In this study, a titanium rod was implanted in the medullary cavity of one femoral metaphysis in OVX rats, and then the rats were randomly divided into four groups: Sham group (Sham, n = 10), OVX rat group (OVX, n = 10), melatonin day treatment group (OVX + MD, n = 10), and melatonin night treatment group (OVX + MN, n = 10). The OVX + MD and OVX + MN rats were treated with 30 mg/kg/day melatonin at 9 am and 9 pm, respectively, for 12 weeks. At the end of the research, the rats were killed to obtain bilateral femora and blood samples for evaluation. Results. Micro-CT and histological evaluation showed that the bone microscopic parameters of femoral metaphysis trabecular bone and bone tissue around the titanium rod in the OVX + MD group demonstrated higher bone mineral density, bone volume fraction, trabecular number, connective density, trabecular thickness, and lower trabecular speculation (p = 0.004) than the OVX + MN group. Moreover, the biomechanical parameters of the OVX + MD group showed higher pull-out test and three-point bending test values, including fixation strength, interface stiffness, energy to failure, energy at break, ultimate load, and elastic modulus (p = 0.012) than the OVX + MN group. In addition, the bone metabolism index and oxidative stress indicators of the OVX + MD group show lower values of Type I collagen cross-linked C-telopeptide, procollagen type 1 N propeptide, and malondialdehyde (p = 0.013), and higher values of TAC and SOD (p = 0.002) compared with the OVX + MN group. Conclusion. The results of our study suggest that systemic administration with melatonin at 9 am may improve the initial osseointegration of titanium rods under osteoporotic conditions more effectively than administration at 9 pm. Cite this article: Bone Joint Res 2022;11(11):751–762

Aims. To investigate the risk factors for unsuccessful radial head reduction (RHR) in children with chronic Monteggia fractures (CMFs) treated surgically. Methods. A total of 209 children (mean age 6.84 years (SD 2.87)), who underwent surgical treatment for CMFs between March 2015 and March 2023 at six institutions, were retrospectively reviewed. Assessed risk factors included age, sex, laterality, dislocation direction and distance, preoperative proximal radial metaphysis width, time from injury to surgery, reduction method, annular ligament reconstruction, radiocapitellar joint fixation, ulnar osteotomy, site of ulnar osteotomy, preoperative and postoperative ulnar angulation, ulnar fixation method, progressive ulnar distraction, and postoperative cast immobilization. Independent-samples t-test, chi-squared test, and logistic regression analysis were used to identify the risk factors associated with unsuccessful RHR. Results. Redislocation occurred during surgery in 48 patients (23%), and during follow-up in 44 (21.1%). The mean follow-up of patients with successful RHR was 13.25 months (6 to 78). According to the univariable analysis, time from injury to surgery (p = 0.002) and preoperative dislocation distance (p = 0.042) were identified as potential risk factors for unsuccessful RHR. However, only time from injury to surgery (p = 0.007) was confirmed as a risk factor by logistic regression analysis. Receiver operating characteristic curve analysis and chi-squared test confirmed that a time from injury to surgery greater than 1.75 months increased the rate of unsuccessful RHR above the cutoff (p = 0.002). Conclusion. Time from injury to surgery is the primary independent risk factor for unsuccessful RHR in surgically treated children with CMFs, particularly in those with a time from injury to surgery of more than 1.75 months. No other factors were found to influence the incidence of unsuccessful RHR. Surgical reduction of paediatric CMFs should be performed within the first two months of injury whenever possible. Cite this article: Bone Jt Open 2024;5(7):581–591

Aims

The main objective of this study is to analyze the penetration of bone cement in four different full cementation techniques of the tibial tray.

Distal femoral physeal fractures can cause of growth distrurbance which frequently requires further surgical intervention. The aim of this study was to determine if tibial tuberosity ossification at the time of injury can predict further surgery in patients who have sustained a physeal fracture of the distal femur. We retrospectively investigated all patients who had operative treatment for a distal femoral physeal fracture at a paediatric level one trauma center over a 17 year period. Logistic regression analysis was performed investigating associations between the need for further surgery to treat growth disturbance and tibial tuberosity ossification, age, Salter Harris grade, mode of fixation or mechanism of injury. 74 patients met the inclusion criteria. There were 57 boys (77%) and 17 girls (23%). The average age at time of injury was 13.1 years (range 2.-17.1 years). Following fixation, 30 patients (41%) underwent further surgery to treat growth disturbance. Absence of tibial tuberosity fusion to the metaphysis was significantly associated with need for further surgery (p = < 0 .001). Odds of requiring secondary surgery after tibial tuberosity fusion to metaphysis posteriorly (compared with not fused) were 0.12, 95% CI (0.04, 0.34). The estimate of effect of tibial tuberosity ossification on reoperation rates did not vary when adjusted for gender, mechanism, fixation and Salter Harris grade. When accounting for age, the odds of further operation if the tibial tuberosity is fused to the metaphysis posteriorly (compared with not fused) were 0.28, 95% CI (0.08, 0.94). Tibial tuberosity ossification stage at time of injury is a predictor of further surgery to treat growth disturbance in paediatric distal femoral fractures. Children with distal femoral physeal fractures whose tibial tuberosity was not fused to the metaphysis posteriorly were 8.3 times more likely to require further surgery

This study aims to assess the fracture mechanics of type-2 diabetic (T2D) femoral bone using innovative site-specific tests, whilst also examining the cortical and trabecular bone microarchitecture from various regions using micro-computed tomography (CT) of the femur as the disease progresses. Male [Zucker Diabetic Fatty (ZDF: fa/fa) (T2D) and Zucker Lean (ZL: fa/+) (Control)] rats were euthanized at 12-weeks of age, thereafter, right and left femora were dissected (Right femora: n = 6, per age, per condition; Left femora: n=8-9, per age, per condition). Right femurs were notched in the posterior of the midshaft. Micro-CT was used to scan the proximal femur, notched and unnotched femoral midshaft (cortical) of the right femur and the distal metaphysis (trabecular) of the left femur to investigate microarchitecture and composition. Right femurs were fracture toughness tested to measure the stress intensity factor (Kic) followed by a sideways fall test using a custom-made rig to investigate femoral neck mechanical properties. There was no difference in trabecular and cortical tissue material density (TMD) between T2D and control rats. Cortical thickness was unchanged, but trabeculae were thinner (p<0.01) in T2D rats versus controls. However, T2D rats had a greater number of trabeculae (p<0.05) although trabecular spacing was not different to controls. T2D rats had a higher connectivity distribution (p<0.05) and degree of anisotropy (p<0.05) in comparison to controls. There was no difference in the mechanical properties between strains. At 12-weeks of age, rats are experiencing early-stage T2Ds and the disease impact is currently not very clear. Structural and material properties are unchanged between strains, but the trabecular morphology shows that T2D rats have more trabecular struts present in order to account for the thinner trabeculae

Introduction. Treatment pathways of 5. th. metatarsal fractures are commonly directed based on fracture classification, with Jones types for example, requiring closer observation and possibly more aggressive management. Primary objective. To investigate the reliability of assessment of subtypes of 5. th. metatarsal fractures by different observers. Methods. Patients were identified from our prospectively collected database. We included all patient referred to our virtual fracture clinic with a suspected or confirmed 5. th. metatarsal fracture. Plain AP radiographs were reviewed by two observers, who were initially trained on the 5. th. metatarsal classification identification. Zones were defined as Zone 1.1, 1.2, 1.3, 2, 3, diaphyseal shaft (DS), distal metaphysis (DM) and head. An inter-observer reliability analysis using Cohen's Kappa coefficient was carried out, and degree of observer agreement described using Landis & Koch's description. All data was analysed using IBM SPSS v.27. Results. 878 patients were identified. The two observers had moderate agreement when identifying fractures in all zones, apart from metatarsal head fractures, which scored substantial agreement (K=.614). Zones 1.1 (K=.582), 2 (K=.536), 3 (K=.601) and DS (K=.544) all tended towards but did not achieve substantial agreement. Whilst DS fractures achieved moderate agreement, there was an apparent difficulty with distal DS, resulting in a lot of cross over with DM (DS 210 vs 109; DM 76 vs 161). Slight agreement with the next highest adjacent zone was found when injuries were thought to be in zones 1.2, 1.3 and 2 (K=0.17, 0.115 and 0.152 respectively). Conclusions. Reliability of sub-categorising 5. th. metatarsal fractures using standardised instructions conveys moderate to substantial agreement in most cases. If the region of the fracture is going to be used in an algorithm to guide a management plan and clinical follow up during a virtual clinic review, defining fractures of zones 1–3 needs careful consideration

Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation. Materials & Methods. Case 1 - A 12-year-old boy presented with a two-week history of atraumatic right ankle pain. An X-ray demonstrated a distal tibia metaphyseal cyst confirmed on biopsy as an aneurysmal bone cyst. The cyst expanded on interval X-rays from 5.5cm to 8.5cm in 9 weeks. A wide-margin en-bloc resection was performed leaving a 13.8cm tibial defect. A cable transport hexapod frame and a proximal tibial osteotomy was performed, with syndesmosis screw fixation. The transport phase lasted 11 months. While in frame, the boy sustained a distal femur fracture from a fall. The femur and the docking site were plated at the same sitting and frame removed. At one-year post-frame removal he is pain-free, with full ankle dorsiflexion but plantarflexion limited to 25 degrees. He has begun graduated return to sport. Results. Case 2 - A 12-year-old girl was referred with a three-month history of lateral left ankle swelling. X-ray demonstrated an aneurysmal bone cyst in the distal fibula metaphysis. The cyst grew from 4.2 × 2.3cm to 5.2 × 3.32cm in 2 months. A distal fibula resection (6.2cm) with syndesmosis fixation and hexapod cable transport frame were undertaken. The frame was in situ for 13 weeks and during this time she required an additional osteotomy for premature consolidation and had one pin site infection. After 13 weeks a second syndesmosis screw was placed, frame removed, and a cast applied. 3 months later she had fibular plating, BMAC and autologous iliac crest bone graft for slow union. At 3 years post-operative she has no evidence of recurrence, is pain-free and has no functional limitation. Conclusions. We describe two cases of ankle syndesmosis preservation using cable transport for juxta-articular aneurysmal bone cysts. This allows wide resection to prevent recurrence while also preserving primary ankle stability and leg length in children. Both children had a minor complication, but both had an excellent final outcome. Cable bone transport and prophylactic syndesmosis stabilization allows treatment of challenging juxta-articular aneurysmal bone cysts about the ankle. These techniques are especially useful in large bone defects

Introduction. Fibrous dysplasia is a pathological condition, where normal medullary bone is replaced by fibrous tissue and small, woven specules of bone. Fibrous dysplasia can occur in epiphysis, metaphysis or diaphysis. Occationally, biopsy is necessary to establish the diagnosis. We present a review of operative treatment using the Ilizarov technique. The management of tibial fibrous dysplasia in children are curettage or subperiosteal resection to extra periosteal wide resection followed by bone transport. Materials and Methods. A total of 18 patients were treated between 2010 – 2020; 12 patients came with pain and 6 with pain and deformity. All patients were treated by Ilizarov technique. Age ranges from 4–14 years. 12 patients by enbloc excision and bone transportation and 6 patients were treated by osteotomy at the true apex of the deformity by introducing the k/wires in the medullary cavity with stable fixation by Ilizarov device. The longest duration for bone transport was 16 weeks (14–20 weeks) for application, after deformity correction was 20 weeks. We have never used any kind of bone grafts. Results. All the 18 patients were treated successfully by Ilizarov compression distraction device. The patients with localized tibial pathology with deformity had the shortest period on the Ilizarov apparatus, 14 weeks. Conclusions. Preservation and bone regeneration by distraction histogenesis constitutes a highly conservative limb saving surgery. Patients with bone defects of <10 cm, a great deal of preserved healthy tissue and good prognosis are good candidates for these methods

As the number of patients who have undergone total hip arthroplasty rises, the number of patients who require surgery for a failed total hip arthroplasty is also increasing. It is estimated that 183,000 total hip replacements were performed in the United States in the year 2000 and that 31,000 of these (17%) were revision procedures. Reconstruction of the failed femoral component in revision total hip arthroplasty can be challenging from both a technical perspective and in preoperative planning. With multiple reconstructive options available, it is helpful to have a classification system which guides the surgeon in selecting the appropriate method of reconstruction. A classification of femoral deficiency has been developed and an algorithmic approach to femoral reconstruction is presented. An extensively coated, diaphyseal filling component reliably achieves successful fixation in the majority of revision femurs. The surgical technique is straightforward and we continue to use this type of device in the majority of our revision total hip arthroplasties. However, in the severely damaged femur (Type IIIB and Type IV), other reconstructive options may provide improved results. Based on our results, the following reconstructive algorithm is recommended for femoral reconstruction in revision total hip arthroplasty. Type I: In a Type I femur, there is minimal loss of cancellous bone with an intact diaphysis. Cemented or cementless fixation can be utilised. If cemented fixation is selected, great care must be taken in removing the neo-cortex often encountered to allow for appropriate cement intrusion into the remaining cancellous bone. Type II: In a Type II femur, there is extensive loss of the metaphyseal cancellous bone and thus, fixation with cement is unreliable. In this cohort of patients, successful fixation was achieved using a diaphyseal fitting, extensively porous coated implant. However, as the metaphysis is supportive, a cementless implant that achieves primary fixation in the metaphysis can be utilised. Type IIIA: In a Type IIIA femur, the metaphysis is non-supportive and an extensively coated stem of adequate length is utilised to ensure that more than 4cm of scratch fit is obtained in the diaphysis. Type IIIB: Based on the poor results obtained with a cylindrical, extensively porous coated implant (with 4 of 8 reconstructions failing), our present preference is a modular, cementless, tapered stem with flutes for obtaining rotational stability. Type IV: The isthmus is completely non-supportive and the femoral canal is widened. Cementless fixation cannot be reliably used in our experience, as it is difficult to obtain adequate initial implant stability that is required for osseointegration. Reconstruction can be performed with impaction grafting if the cortical tube of the proximal femur is intact. However, this technique can be technically difficult to perform, time consuming and costly given the amount of bone graft that is often required. Although implant subsidence and peri-prosthetic fractures have been associated with this technique, it can provide an excellent solution for the difficult revision femur where cementless fixation cannot be utilised. Alternatively, an allograft-prosthesis composite can be utilised for younger patients in an attempt to reconstitute bone stock and a proximal femoral replacing endoprosthesis used for more elderly patients

As the number of patients who have undergone total hip arthroplasty rises, the number of patients who require surgery for a failed total hip arthroplasty is also increasing. Reconstruction of the failed femoral component in revision total hip arthroplasty can be challenging from both a technical perspective and in pre-operative planning. With multiple reconstructive options available, it is helpful to have a classification system which guides the surgeon in selecting the appropriate method of reconstruction. Type I: Minimal loss of metaphyseal cancellous bone with an intact diaphysis. Often seen when conversion of a cementless femoral component without biological ingrowth surface requires revision. Type II: Extensive loss of metaphyseal cancellous bone with an intact diaphysis. Often encountered after the removal of a cemented femoral component. Type IIIA: The metaphysis is severely damaged and non-supportive with more than 4 cm of intact diaphyseal bone for distal fixation. This type of defect is commonly seen after removal of grossly loose femoral components inserted with first generation cementing techniques. Type IIIB: The metaphysis is severely damaged and non-supportive with less than 4 cm of diaphyseal bone available for distal fixation. This type of defect is often seen following failure of a cemented femoral component that was inserted with a cement restrictor and cementless femoral components associated with significant distal osteolysis. Type IV: Extensive meta-diaphyseal damage in conjunction with a widened femoral canal. The isthmus is non-supportive. Based on our results, the following reconstructive algorithm is recommended for femoral reconstruction in revision total hip arthroplasty. An extensively coated, diaphyseal filling component reliably achieves successful fixation in the majority of revision femurs and the surgical technique is straightforward. However, in the severely damaged femur (Type IIIB and Type IV), other reconstructive options may provide improved results. Type I: Cemented or cementless fixation can be utilised. If cemented fixation is selected, great care must be taken in removing the neo-cortex often encountered to allow for appropriate cement intrusion into the remaining cancellous bone. Type II: In this cohort of patients, successful fixation was achieved using a diaphyseal fitting, extensively porous coated implant. However, as the metaphysis is supportive, a cementless implant that achieves primary fixation in the metaphysis can be utilised. Type IIIA: An extensively coated stem of adequate length is utilised to ensure that more than 4 cm of scratch fit is obtained in the diaphysis. Type IIIB: Our present preference is a modular, cementless, tapered stem with flutes for obtaining rotational stability. Type IV: Cementless fixation cannot be reliably used in our experience, as it is difficult to obtain adequate initial implant stability that is required for osseointegration. Reconstruction can be performed with impaction grafting if the cortical tube of the proximal femur is intact. However, this technique can be technically difficult to perform, time consuming and costly given the amount of bone graft that is often required. Although implant subsidence and peri-prosthetic fractures (both intra-operatively and post-operatively) have been associated with this technique, it can provide an excellent solution for the difficult revision femur where cementless fixation cannot be utilised. Alternatively, an allograft-prosthesis composite can be utilised for younger patients in an attempt to reconstitute bone stock and a proximal femoral replacing endoprosthesis used for more elderly patients

There is no mathematical relationship between the internal diameter of the femoral metaphysis and diaphysis. Unless an infinite number of monolithic stems are available with variable metaphyseal and diaphyseal diameters, which is not economically possible, even in virgin cases, the surgeon has to decide if the stem is going to fit in the metaphysis or the diaphysis. It is not possible to match both. In revision cases with a hollowed out metaphysis, the situation is much worse. As it is obviously easier to fit the diaphysis, this is what stems such as the AML and Wagner stem have done. They completely ignore the metaphysis and obtain fixation in the diaphysis. This is all well and good, but it means that the proximal femur is unloaded, like an astronaut in space. While, there will be some recovery due to removal of the toxins and local muscle pull, it will be incomplete. Furthermore, should sepsis occur, one is faced with the horror of removing a distally fixed implant. Clearly, if proximal fixation, i.e. above the level of lesser trochanter could reliably be achieved, this would be preferable in terms of proximal loading leading to bone recovery and ease of removal should it be required. The only way that proximal loading can be achieved is if the metaphyseal and diaphyseal parts of the component can be varied infinitely. This clearly can only be achieved by using a modular stem. The concern with modularity always has been fretting at the sleeve-stem locking mechanism with release of metal ions. The stem, which I have been using for the last 25 years, is the SROM stem. Fretting and ion release had never been an issue. As the components are made of a relatively soft titanium alloy, it is likely that the sleeve and the stem cold weld, thus, eliminating any movement and eliminating friction. I have a follow-up of roughly 120 revision cases with a minimum follow-up of 5 years and a maximum follow-up of 22 years. I have no loosening in easy revision cases where a primary stem was used. I have had some loosenings in extremely difficult revision situations where a long bowed stem was required, but even then, the loosening rate is less than 3%. I use this stem in primary situations, i.e. in about 80% of all the primaries I have done. This means I have done roughly 1500 cases or more. Other than some late infections, I have never, ever had any stem loosening in a simple case. Obviously, I have had loosenings in some cases, where we have been doing fancy shortening or de-rotation osteotomies, but none in simple primary cases. I would, therefore, suggest that the surgeon, if he wishes to use this stem, please try it out on some simple primary cases. The ability to vary distal and proximal internal diameters and proximal geometry makes for easy surgery. I have been using this stem for 25 years and continue to use it in all my primary noncemented cases. I believe in the adage of “train hard and fight easy.” I think that surgeons should not get themselves into a situation where they are forced in a difficult case to use something they have never seen before

Introduction. We report 3 cases from different centres of infantile tibia vara in which the deformity was due to slippage of the proximal tibial epiphysis on the metaphysis; the aim of this study was to define the features of this previously unreported condition, and their implications for management. Method. Three cases of tibia vara secondary to atraumatic slippage of the upper tibial epiphysis on the metaphysis were identified from three different centres. The case notes and imaging studies were retrospectively reviewed to distinguish common clinical and radiographic features. Results. There were one male and two females, all of non-Caucasian origin, (age 3–7 years). All patients' weights were above the 97th centile for age. In all cases there was an infero-medial subluxation of the tibial epiphysis over a dome shaped proximal tibial metaphysis, with disruption of continuity between their lateral borders. The height of the medial tibial plateau was preserved in all cases. New bone formation suggests this is a chronic process. The evolution of one case indicates that pathogenesis is shared with infantile Blount's disease. A gradual deformity correction was performed in all cases using circular external fixation, with the proximal ring secured to both the proximal epiphysis and metaphysis. Conclusion. Slipped upper tibial epiphysis is an uncommon but distinct cause of tibia vara. The radiological features are completely different from those previously described for infantile tibia vara and not encompassed by the existing classification. The unusual morphology has consequences for treatment. Management is analogous to a slipped upper femoral epiphysis – the physis has to be stabilized to the metaphysis and an osteotomy performed to restore the mechanical axis. We believe this is best achieved with a circular external fixator because this permits multiaxial correction including translation and rotation

INTRODUCTION:. Modular femoral stems of Total Hip Arthroplasty (THA) have been designed to fit the metaphysis and diaphysis separately. Clinical results with modular femoral stems are reported to be satisfactory, but there exists several concerns with modular implant connections, including fretting corrosion, fracture of implant, and dissociation the stem from the proximal sleeve. Recently, we have become aware of another potential consequence of the modular design: sleeve deformation secondary to forces encountered during insertion. In our patients, we noted that the stems would not fully seat in the machined taper of the sleeve, indicating that some type deformation to the sleeve had occurred. We began an in vivo study to characterize this phenomenon. The objectives of this study were (1) Does deformation occur by impacting the sleeve into the metaphysis? (2) If so, quantify the sleeve deformation in hip arthroplasty patients. MATERIALS AND METHODS:. One man and 7 women undergoing primary THA were enrolled. This project was approved by IRB. This modular system (4-U CLS; Nakashima Medical Co., Japan) consists of a metaphyseal sleeve that connects with the diaphyseal stem via a Morse taper. The sleeve was impacted into the metaphysis first, followed by the stem. A custom taper gauge for each size of sleeve (Figure 1A) was inserted into the sleeve before and after impacting the sleeve into the metaphysis, and the distance between the top of the sleeve and the top of the gauge was measured using a caliper (* in Figure 1B). Deformation was defined as the difference in distance between the before and the after impacted dimensions. Preoperative femoral morphology, assessed using Dorr classification system, was type A in 2 hips, type B in 5 hips, and type C in 1 hip. RESULTS:. Intraoperatively, all sleeves had measurable deformity. Deformation ranged from 0.1 to 3.2 mm and averaged 1.18 ± 1.11 mm. Deformation was marginally related to bone type. Sleeve implanted into type A bone experienced 2.45 mm deformation, sleeve implanted into type B bone experienced 0.88 mm deformation, and sleeve implanted into type C bone experienced 0.1 mm deformation (Figure 2). And the largest deformation was observed at 51 years youngest male patient. DISCUSSION:. The small number studied in this study is a limitation. And we are not certain how long the deformation of the sleeve lasts. Despite the limitations, this study showed that deformation of sleeve occurred by impacting the sleeve into the metaphysis, and sleeves implanted into harder bone experienced larger mean deformation than sleeves implanted into less dense bone. This phenomenon may not have been a relevant issue in the past, but recent studies have reported the deformation of metal acetabular cup. The deformation can affect the torsional stability of modular implant connection and fretting corrosion, so further investigation will be needed. The modular femoral stem with sleeve remains an excellent design, providing good initial stability and long-term results. However, greater understanding of sleeve is important to orthopaedic surgeons

Introduction and Objective. Klinefelter Syndrome (KS, karyotype 47,XXY) is the most frequent chromosomal aneuploidy in males, as well as the most common cause of infertility in men. Patients suffer from a lack of testosterone, i.e. hypergonadotropic hypogonadism provoking infertility, but KS men also show an increased predisposition to osteoporosis and a higher risk of bone fracture. In a mouse model for human KS, bone analysis of adult mice revealed a decrease in bone mass that could not be rescued by testosterone replacement, suggesting a gene dosage effect originating from the supernumerary X-chromosome on bone metabolism. Usually, X chromosome inactivation (XCI) compensates for the dosage imbalance of X-chromosomal genes between sexes. Some studies suggested that expression of genes that escape silencing of the supernumerary X-chromosome (e.g. androgen receptor) has an impact on sex differences, but may also cause pathological changes in males. As a promising new such candidate for a musculoskeletal escape gene, we identified the integral membrane protein (ITM) 2a, which is encoded on the X-chromosome and related to enchondral ossification. The aim of the project was to characterize systemic bone loss in the course of aging in our KS mouse model, and whether the supernumerary X-chromosome causes differences in expression of genes related to bone development. Materials and Methods. Bone structure of 24 month (=aged) old male wild type (WT) and 41, XXY mice (B6Ei.Lt-Y) were analysed by μCT. Afterwards bones were paraffin embedded and cut. In addition, tissue of brain, liver, kidney, lung and heart were also isolated and embedded for IHC staining. Using an anti-ITM2a antibody, expression and cellular localization of ITM2a was evaluated. IHC was also performed on musculoskeletal tissue of WT embryos (E18.5) and neonatal mice to determine possible age-related differences. Results. In 24 month old mice, the analysis of the lumbar vertebrae revealed a significantly lower BV/TV, trabecular bone volume and trabecular number in the XXY- group compared to WT. Trabecular thickness appeared lower but did not reach significance, with the cortical thickness being significantly higher in the XXY- group. High expression of ITM2a was detected in bone slices of both karyotypes in the chondrocytes inside the growth plate, as well as in megakaryocytes and leucocytes as well as endothelial cells of blood vessels inside the bone marrow. Osteocytes, along with erythrocytes and erythropoetic stem cells were negative for ITM2a. Other organs that showed ITM2a positive staining were kidney (blood vessels), heart (muscle) and brain (different structures). Liver and lung tissue were negative for ITM2a. No obvious difference in the intensity of the ITM2a-expression was observed between the WT and the XXY-karyotype. Analyses of embryotic bone tissue (WT) showed high expression of ITM2a in proliferating, hypertrophic and resting chondrocytes in the growth plates of tibia and femur. In comparison, the neonatal animals (WT) did not show any protein-expression in chondrocytes. Furthermore, within the metaphysis of both, embryotic and neonatal bones, endothelial cells and osteoblasts were ITM2a-positive. Further analyses of bones and tissues from young mice (4–6 month) are ongoing. Conclusions. Bone analyses revealed a significant reduction in trabecular bone mass along with fewer and thinner trabeculae in XXY mice compared to the WT, especially in the spine. ITM2a expression was visible in different cell types inside the bone, and in addition, different expression patterns at different stages of development (embryonic/neonatal) were observed. However, we have not found a significant difference in the quantity of ITM2a between tissues of XXY-karyotypes and WT. Further analyses of X-chromosomal encoded and therefore dysregulated modulators in XXY-karyotype mice and patients may reveal new sex chromosomal effector proteins in bone metabolism

INTRODUCTION. Wedge femoral stems used in total hip arthroplasty (THA) have evolved with modifications including shorter lengths, reduced distal geometries, and modular necks. Unlike fit and fill stems which contact most of the metaphysis, tapered wedge femoral stems are designed to achieve proximal medial/lateral fixation. These single taper, wedge stems have demonstrated positive clinical outcomes. The tapered wedge stem evaluated in this study has further reduced distal geometry to provide a wedge-fit within the metaphysis of the proximal femoral canal for all femur types (Dorr A, B, C). The objective of this study was to evaluate the early clinical outcomes, including femoral stem subsidence, of a tapered wedge femoral stem. METHODS. Fifty subjects (28 males, 22 females; mean age: 64.7±9.7 years; mean BMI: 29.6±4.6) underwent primary THA with a tapered wedge femoral stem. IRB approval was received prior to conducting the study and all participants signed the informed consent. Clinical data outcomes for this study included the Harris Hip Score (HHS), the Oxford Hip Score (OHS), revisions, and subsidence at the 6-week, 3-month, 1-year, and 2-year post-operative time points. Femoral stem subsidence was measured by an independent third party. Student t-tests were used to identify significant mean differences between genders (p<0.05). RESULTS. For patients returning for their 2-year post- operative visit (n=42), the HHS improved by 40.7 points to 91.9 from 51.2 and the OHS improved by 23.5 points to 44.6 from 21.1. There was no significant difference between genders with regard to age, BMI, or HHS scores. However, the males had significantly higher pre-operative OHS scores (23.4 vs. 18.2) and 3-month post-operative OHS scores (43.7 vs. 40.3). There were no revisions. There were no observations of femoral stem subsidence at 1 year (n=45) or 2 years (n=40). DISCUSSION. The tapered wedge femoral stem exhibited positive early clinical results as demonstrated by the significant improvement in functional outcome scores from the pre-operative visit to 2-years post-operative. These 2-year improvements are better than moderate clinically important improvements reported in the literature (40.1 points for HHS). Functional outcomes scores continued to improve at the 6-week, 3-month, and 1-year post-operative visits. The 1-year and 2-year outcomes were not significantly different. Additionally, the implant was well fixated as there were no reports of femoral stem subsidence 2 years post-operative. SIGNIFICANCE. The tapered wedge femoral stem evaluated in this study demonstrated positive early clinical performance with no reports of femoral stem subsidence or revisions. This tapered wedge stem design is a promising alternative to conventional femoral stems

Introduction. Circumferential periosteal release is a rarely reported procedure for paediatric limb lengthening. The technique involves circumferential excision of a strip of periosteum from the metaphysis of the distal femur, tibia and fibula. This study aims to determine the mid to long-term effectiveness of this technique. Materials and Methods. A retrospective case series was performed of all patients undergoing circumferential periosteal release of the distal femur and/or tibia between 2006 and 2017. Data collected included demographics, surgical indication, post-operative limb-lengths and complications. Data collection was stopped if a further procedure was performed that may affect limb-length (except a further release). Leg-length discrepancies were calculated as absolute values and as percentages of the longer limb-length. Final absolute and percentage discrepancies were compared to initial discrepancies using a paired t-test. Results. Eighteen patients (11 males) were identified, who underwent 25 procedures. The mean age at first surgery was 5.83 (SD 3.49). The commonest indication was congenital limb deficiency (13 patients). In 23 procedures the periosteum was released in two limb segments (distal femur and distal tibia), whereas in two patients it was released in a single limb segment. Five patients underwent repeat periosteal release, and one patient had three periosteal releases. Mean follow-up was 63.1 months (SD 33.9). Fifteen patients had sufficient data for statistical analysis. The mean initial absolute discrepancy was 2.01cm (SD 1.13), and the mean initial percentage discrepancy was 4.09% (SD 2.76). The mean final absolute discrepancy was 1.00cm (SD 1.62), and the mean percentage final discrepancy was 1.37% (SD 2.42). The mean reduction in absolute discrepancy was 0.52 cm (95%CI −0.04–1.08; p=0.068, paired t-test), and the mean reduction in percentage discrepancy was 2.00% (95% CI 1.02–2.98, p=<0.001 paired t-test). In five patients the operated limb overgrew the shorter limb. Conclusions. Circumferential periosteal release produces a modest decrease in both absolute and percentage limb-length discrepancy, although the outcome is variable and some patients may experience overgrowth of the operated limb

Revision of the failed femoral component can be challenging. Multiple reconstructive options are available and the procedure is technically difficult and thus meticulous pre-operative planning is required. The Paprosky Femoral Classification is useful as it helps the surgeon determine what bone stock is available for fixation and hence, which type of femoral reconstruction is most appropriate. Type 1 Defect: This is essentially a normal femur and reconstruction can proceed as the surgeon would with a primary femur. Type 2 Defect: The metaphysis is damaged but still supportive and hence a stem that gains primary fixation in the metaphysis can be used. Type 3 Defect: The metaphysis is damaged and non-supportive and hence a stem that gains primary fixation in the diaphysis is required. Broken down into types “A” and “B” based on the amount of intact isthmus available for distal fixation. Type 3A Defect: >4 cm of intact femoral isthmus is present. Can be managed with a fully porous coated stem, so long as the diameter is <18 mm and torsional remodeling is not present. Type 3B Defect: There is < 4 cm of intact femoral isthmus and based on lower rates of osseointegration if a fully porous coated stem is used, a modular titanium tapered stem is recommended. Type 4 Defect: The most challenging to manage as there is no isthmus available for distal fixation. Can be managed with proximal femoral replacement if uncontained and impaction grafting if contained. We have also successfully used modular titanium tapered stems that appear to gain “3-point fixation” in this type of defect

INTRODUCTION: As the number of patients who have undergone total hip arthroplasty rises, the number of patients who require surgery for a failed total hip arthroplasty is also increasing. It is estimated that 183,000 total hip replacements were performed in the United States in the year 2000 and that 31,000 of these (17%) were revision procedures. Reconstruction of the failed femoral component in revision total hip arthroplasty can be challenging from both a technical perspective and in pre-operative planning. With multiple reconstructive options available, it is helpful to have a classification system which guides the surgeon in selecting the appropriate method of reconstruction. DISCUSSION: An extensively coated, diaphyseal filling component reliably achieves successful fixation in the majority of revision femurs. The surgical technique is straightforward and we continue to use this type of device in the majority of our revision total hip arthroplasties. However, in the severely damaged femur (Type IIIB and Type IV), other reconstructive options may provide improved results. Based on our results, the following reconstructive algorithm is recommended for femoral reconstruction in revision total hip arthroplasty: TYPE I: In a Type I femur, there is minimal loss of cancellous bone with an intact diaphysis. Cemented or cementless fixation can be utilised. If cemented fixation is selected, great care must be taken in removing the neo-cortex often encountered to allow for appropriate cement intrusion into the remaining cancellous bone. TYPE II: In a Type II femur, there is extensive loss of the metaphyseal cancellous bone and thus fixation with cement is unreliable. In this cohort of patients, successful fixation was achieved using a diaphyseal fitting, extensively porous coated implant in 26 of 29 cases (90%) However, as the metaphysis is supportive, a cementless implant that achieves primary fixation in the metaphysis can be utilized. TYPE III A: In a Type IIIA femur, the metaphysis is non-supportive and an extensively coated stem of adequate length is utilised to ensure that more than 4 cm of scratch fit is obtained in the diaphysis. TYPE III B: Based on the poor results obtained with a cylindrical, extensively porous coated implant, our present preference is a modular, cementless, tapered stem with flutes for obtaining rotational stability. Excellent results have been reported with this type of implant and by virtue of its tapered design, excellent initial axial stability can be obtained even in femurs with a very short isthmus. Subsidence has been reported as a potential problem with this type of implant and they can be difficult to insert. However, with the addition of modularity to many systems that employ this concept of fixation, improved stability can be obtained by impacting the femoral component as far distally as needed while then building up the proximal segment to restore appropriate leg length. TYPE IV: In a Type IV femur, the isthmus is completely non-supportive and the femoral canal is widened. Cementless fixation cannot be reliably used in our experience, as it is difficult to obtain adequate initial implant stability that is required for osseointegration. Reconstruction can be performed with impaction grafting if the cortical tube of the proximal femur is intact. However, this technique can be technically difficult to perform, time consuming and costly given the amount of bone graft that is often required. Although implant subsidence and peri-prosthetic fractures have been associated with this technique, it can provide an excellent solution for the difficult revision femur where cementless fixation cannot be utilised. Alternatively, an allograft-prosthesis composite can be utilised for younger patients in an attempt to reconstitute bone stock and a proximal femoral replacing endoprosthesis used for more elderly patients

Introduction: Screws placed in the fibula do not have a satisfactory purchase during internal fixation of an osteoporotic ankle fracture. Tibia-pro-fibula screws that extend from the fibula into the distal tibial metaphysis provide additional purchase. The purpose of this study is to investigate if purchase of these screws can be enhanced further by injecting calcium sulfate and calcium phosphate composite graft in the drill holes prior to insertion of the screws. Methods: Bone density was quantified using DEXA scan in paired cadaver legs. One leg from each pair was randomly selected for injection of composite graft into screw holes before insertion of the screws. Two screws were inserted through the fibula into the distal tibial metaphysis in each leg, at the level of the syndesmosis under fluoroscopy in a standardized fashion using a jig. The screws were pulled out using a materials testing machine. Stiffness, force, displacement, and energy required were recorded. Results: After testing 4 pairs of cadaver legs, a statistically significant difference was noted in displacement, failure load, and failure energy between augmented and non-augmented screws, with the augmented screws being considerably stronger. Of the two screws the distal, when compared to the proximal one, required more displacement, higher force and energy to fail whether augmented with composite graft or not. Conclusion: Screws augmented with composite graft provide significantly greater purchase in an osteoporotic distal tibial metaphysis than non-augmented screws. Clinical relevance: Use of composite graft to augment purchase of the screws inserted in the distal tibial metaphysis may enhance the stability of the internal fixation of an osteoporotic ankle fracture. This will enable early weight-bearing mobilization and return to function which is important in elderly patients

Osteosarcoma (OS) is the most prevalent bone tumor in children and young adults. Most tumors arise from the metaphysis of the long bones and easily metastasize to the lungs. Current therapeutic strategies of osteosarcoma are routinely surgical resection and chemotherapy, which are limited to the patients suffering from metastatic recurrence. Therefore, to investigate molecular mechanisms that contribute to osteosarcoma progression is very important and may shed light on targeted therapeutic approach to improve the survival of patients with this disease. Several miRNAs have been found expressed differentially in osteosarcoma (OS), In this study, we found that miR-144 significantly suppresses osteosarcoma cell proliferation, migration andinvasion ability in vitro, and inhibited tumor growth and metastasisin vivo. The function and molecular mechanism of miR-144 in Osteosarcoma was further investigated. Tissue samples from fifty-one osteosarcoma patients were obtained from Shanghai Ninth People's Hospital. The in vitro function of miR-144 in Osteosarcoma was investigated by cell viability assay, wound healing assay, invasion assay, the molecular mechanism was identified by Biotin-coupled miRNA capture, Dual-luciferase reporter assays, etc. the in vivo function of miR-144 in osteosarcoma was confirmed by osteosarcoma animal model and miR-144−/− zebrafish model. Mechanically, we demonstrated that Ras homolog family member A (RhoA) and its pivotal downstream effector Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) were both identified as direct targets of miR-144. Moreover, the negative co-relation between downregulated miR-144 and upregulated ROCK1/RhoA was verified both in the osteosarcoma cell lines and clinical patients' specimens. Functionally, RhoA with or without ROCK1 co-overexpression resulted a rescue phenotype on the miR-144 inhibited cell growth, migration and invasion abilities, while individual overexpression of ROCK1 had no statistical significance compared with control in miR-144 transfected SAOS2 and U2-OS cells. This study demonstrates that miR-144 inhibited tumor growth and metastasis in osteosarcoma via dual-suppressing of RhoA and ROCK1, which could be a new therapeutic approach for the treatment ofosteosarcoma