Patient-specific instrumentation in total ankle arthroplasty

The recent increase in the adoption of total ankle arthroplasty(TAA)reflects the improvements in implant designs and surgical techniques,including the use of preoperative navigation system and patient-specific instrumentation(PSI),such as custom-made cutting guides.Cutting guides are customized with respect to each patient's anatomy based on preoperative ankle computed tomography scans,and they drive the saw intra-operatively to improve the accuracy of bone resection and implant positioning.Despite some promising results,the main queries in the literature are whether PSI improves the reliability of achieving neutral ankle alignment and more accurate implant sizing,whether it is actually superior over standard techniques,and whether it is cost effective.Moreover,the advantages of PSI in clinical outcomes are still theoretical because the current literature does not allow to confirm its superiority.The purpose of this review article is therefore to assess the current literature on PSI in TAA with regard to current implants with PSI,templating and preoperative planning strategies,alignment and sizing,clinical outcomes,cost analysis,and comparison with standard techniques.

Preoperative and postoperative risk factors for periprosthetic joint infection in primary total hip arthroplasty:A 1-year experience

BACKGROUND Periprosthetic joint infection(PJI)in primary total hip replacement(THR)is one of the most important threats in orthopedic surgery,so one important surgeon’s target is to avoid or early diagnose a PJI.Although the incidence of PJI is very low(0.69%)in our department,with an average follow-up of 595 d,this infection poses a serious threat due to the difficulties of treatment and the lower functional outcomes after healing.AIM To study the incidence of PJI in all operations occurring in the year 2016 in our department to look for predictive signs of potential infection.METHODS We counted 583 THR for 578 patients and observed only 4 cases of infection(0.69%)with a mean follow-up of 596 d(min 30,max 1451).We reviewed all medical records to collect the data:duration and time of the surgery,presence,type and duration of the antibiotic therapy,preoperative diagnosis,blood values before and after surgery,transfusions,presence of preoperative drugs(in particularly anticoagulants and antiaggregant,corticosteroids and immunosuppressants),presence of some comorbidities(high body mass index,blood hypertension,chronic obstructive pulmonary disease,cardiac ischemia,diabetes,rheumatological conditions,previous local infections).RESULTS No preoperative,intraoperative,or postoperative analysis showed a higher incidence of PJI.We did not find any class with evident major odds of PJI.In our study,we did not find any border value to predict PJI and all patients had similar values in both groups(non-PJI and PJI).Only some categories,such as female patients,showed more frequency of PJI,but this difference related to sex was not statistically significant.CONCLUSION We did not find any category with a higher risk of PJI in THR,probably due to the lack of few cases of infection.

Off-the-shelf 3D printed titanium cups in primary total hip arthroplasty

Three-dimensional(3D)-printed titanium cups used in primary total hip arthroplasty(THA)were developed to combine the benefits of a low elastic modulus with a highly porous surface.The aim was to improve local vascularization and bony ingrowth,and at the same time to reduce periprosthetic stress shielding.Additive manufacturing,starting with a titanium alloy powder,allows serial production of devices with large interconnected pores(trabecular titanium),overcoming the drawbacks of tantalum and conventional manufacturing techniques.To date,3D-printed cups have achieved dependable clinical and radiological outcomes with results not inferior to conventional sockets and with good rates of osseointegration.No mechanical failures and no abnormal ion release and biocompatibility warnings have been reported.In this review,we focused on the manufacturing technique,cup features,clinical outcomes,open questions and future developments of off-the-shelf 3D-printed titanium shells in THA.

Primary malignant tumors of bone surface:a review with emphasis in differential diagnosis

Surface tumors of the bone are broadly defined as a diverse group of osteogenic and chondrogenic benign and malignant neoplasms that arise adjacent to the outer surface of cortical bone.They may be a cause of diagnostic difficulty due to a degree of histological overlap,rarity,and nomenclature.In this review we summarize the different histological types of primary malignant tumors of bone surface,namely,secondary peripheral chondrosarcoma,periosteal chondrosarcoma,parosteal osteosarcoma,dedifferentiated parosteal osteosarcoma,periosteal osteosarcoma,and high-grade surface osteosarcoma.We provide a comprehensive updated review of their pathogenesis and highlight radiological,macroscopic,and histopathological features and recently available ancillary diagnostic tools that may aid in the differential diagnosis.

Biomechanical modeling of metal screw loadings on the human vertebra

During spinal fusion surgery,angled screw insertion can provide a more favorable stress distribution reducing failure events(screw breakage and loosening).Finite element(FE)analysis can be employed for identifying the optimal insertion path,preventing stress concentrations,and ensuring a lower failure incidence.In this work,a patient-specific FE model of L4 vertebra,virtually implanted with two pedicle screws,was obtained from diagnostic images and numerically investigated.Linearly elastic,inhomogeneous,and isotropic material properties were assigned to bone based on density distributions reconstructed from the medical images.The mechanical response of the screws-vertebra system was analyzed through a progressive damage procedure,considering a stress-based criterion.Different screws insertion angles were simulated,as well as physiological loading conditions.In each loading case,screw orientation influences the fracture mechanism(i.e.,brittle or ductile one),as well as the fracture pattern and load.Besides,stresses in trabecular bone and pedicle screws are significantly affected by the screw configuration.The caudomedial trajectory indicates the most safe case,significantly reducing the stress concentrations in both trabecular bone and screws.Our findings aim to furnish a useful indication to surgeons regarding the screws insertion angle,further reducing the failure risk and improving the clinical outcome of the fixation procedure.

Biosynthetic scaffolds for partial meniscal loss:A systematic review from animal models to clinical practice

Acute or degenerative meniscus tears are the most common knee lesions.Meniscectomy provides symptomatic relief and functional recovery only in the short-to mid-term follow-up but significantly increases the risk of osteoarthritis.For this reason,preserving the meniscus is key,although it remains a challenge.Allograft transplants present many disadvantages,so during the last 20 years preclinical and clinical research focused on developing and investigating meniscal scaffolds.The aim of this systematic review was to collect and evaluate all the available evidence on biosynthetic scaffolds for meniscus regeneration both in vivo and in clinical studies.Three databases were searched:46 in vivo preclinical studies and 30 clinical ones were found.Sixteen natural,15 synthetic,and 15 hybrid scaffolds were studied in vivo.Among them,only 2 were translated into clinic:the Collagen Meniscus Implant,used in 11 studies,and the polyurethane-based scaffold Actifit®,applied in 19 studies.Although positive outcomes were described in the short-to mid-term,the number of concurrent procedures and the lack of randomized trials are the major limitations of the available clinical literature.Few in vivo studies also combined the use of cells or growth factors,but these augmentation strategies have not been applied in the clinical practice yet.Current solutions offer a significant but incomplete clinical improvement,and the regeneration potential is still unsatisfactory.Building upon the overall positive results of these“old”technologies to address partial meniscal loss,further innovation is urgently needed in this field to provide patients better joint sparing treatment options.

致约翰·亨特的感谢信

皇家马斯登医院的临床医生写给18世纪外科医生的感谢信，感谢他在骨肉瘤领域中开创性的、记录详尽的研究。非常感谢您对您的患者的详细病史记录，他的大腿上有一肿块。我们有幸在皇家马斯登医院的肉瘤科回顾这些病例记录和标本。我们很抱歉超过了癌症治疗等待时间的要求，尽管您的患者在1786年留下记录时，皇家马斯登医院还未建立（1851年创立）。

Pulmonary hamartoma:a clinic-pathologic study of 206 consecutive cases focusing on different histologic variants

Background:Pulmonary hamartoma(PH)is the most common benign pulmonary tumor usually presenting as a solitary,well-demarcated nodule composed of mature cartilage and adipose tissue.Some unusual histologic variants are challenging on clinic-radiologic and pathologic examination.Methods:We collected a multicentric,retrospective,consecutive series of 206 PH with clinical characteristics and histologic variants.Results:Clinical data were in line with the literature demonstrating a male prevalence(2:1)and a median age of 61.6 years.The median size of the nodule was 17.8 mm.When performed,SUVmax>2.5 at FDC-PET was evidenced in 4%of cases(5 out of 119)and was significantly associated with undifferentiated/myxoid histology.Conventional histology showing chondroid or chondro-lipomatous PH was quoted in 186 cases(90%),while leiomyomatous and undifferentiated/myxoid variants were recorded in 20 cases(10%).The high rate of unusual variants on pathology is possibly related to a selection bias due to external consultations or surgical excision of the lesions lacking classic features at imaging studies.Conclusions:About 10% of PH may show unusual histology and SUVmax>2.5 at FDC-PET in 4%.These uncommon findings may challenge the correct recognition,raising some concerns in terms of differential diagnosis with several other mesenchymal tumors in the lung.These features should be kept in mind to achieve a correct diagnosis and avoid unnecessary invasive treatments.