Proximal Tibial Bone Research Articles

Reconstruction for Massive Proximal Tibial Bone Defects Using Patient-Customized Three-Dimensional-Printed Metaphyseal Cones in Revision Total Knee Arthroplasty.

ObjectiveTo review the clinical outcomes of revision total knee arthroplasty (RTKA) with massive proximal tibial bone defects using patient‐customized three‐dimensional (3D) printed highly porous metaphyseal cones.MethodsA retrospective study of all patients at our institution who underwent RTKA with the Anderson Orthopaedic Research Institute type III tibial defects using patient‐customized 3D‐printed highly porous metaphyseal cones was performed from 2016 to 2018. Seven patients were enrolled in this study. General results (age, sex, and body mass index); intraoperative results (interface compatibility and stability, and operating time); and perioperative complications (total blood loss, blood transfusion rate, and deep venous thrombosis) were recorded and analyzed. Clinical improvement and functional evaluation (survivorship of implant, improvement of Hospital for Special Surgery Score and McMaster Universities Osteoarthritis Index, and improvement of range of motion [ROM]), and radiographic improvement and implant evaluation (progressive radiolucent lines or radiographic loosening, and mechanical alignment) were evaluated at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, 2 years, and then annually, postoperatively.ResultsThe mean age at diagnosis was 68 (61–77) years. The mean follow‐up was 25.3 (19–36) months. At the latest follow‐up, no aseptic loosening, prosthetic joint infection, or other complications were noted. The mean Hospital for Special Surgery Score increased from 49 (39–63) to 78 (70–83) (P < 0.01), whereas the mean Western Ontario and McMaster Universities Osteoarthritis Index increased from 59 (46–73) to 26 (12–38) (P < 0.01). All patients achieved improved postoperative ROM with the mean flexion angle increasing from 66° (30°–80°) to 93° (80°–100°), and improved mechanical alignment with all hip–knee–ankle (HKA) angles within ±3°.ConclusionsThe patient‐customized 3D‐printed metaphyseal cone is useful technique for reconstructing massive proximal tibial bone defects, with encouraging clinical and radiological outcomes in RTKA.

Locking compression plate + T-type steel plate for postoperative weight bearing and functional recovery in complex tibial plateau fractures.

BACKGROUNDComplex tibial plateau fractures can seriously affect quality of life and physical and mental health of patients. The anatomical relationship between the proximal tibial bone and soft tissue is complex, resulting in different types of tibial plateau fractures. Violent trauma can lead to displaced fracture, serious soft tissue injury, and potentially, dislocation of the knee joint. Therefore, tibial plateau fractures are extremely unstable.AIMTo assess the use of locking compression plate (LCP) + T-type steel plate for postoperative weight bearing and functional recovery of complex tibial plateau fractures.METHODSNinety-seven patients with complex tibial plateau fractures who underwent surgery at our hospital were selected for retrospective study. Forty-nine patients had been treated with LCP + T-type steel plate limited internal fixation (study group), and 48 patients with bilateral ordinary steel plate support (control group). The operation process index, postoperative rehabilitation related index, Rasmussen score of the knee joint, tibial plateau varus angle (TPA), tibial plateau retroversion angle (PA), and surgical complications of the two groups were compared. RESULTSThe operation time and intraoperative bone graft volume in the study group were lower than those in the control group (P < 0.05). There were no significant differences in surgical bleeding, anterior external incision length, postoperative drainage, hospital stay duration, and fracture healing time between the groups (P > 0.05). There was no significant difference in the TPA and PA angle between the groups immediately and 18 mo after surgery (P > 0.05). At 12 mo after surgery, the Rasmussen scale score was higher in the study group than in the control group (P < 0.05). There was no significant difference in the Rasmussen scale score at 18 mo after surgery, and the radiology score at 12 and 18 mo after surgery, between the two groups (P > 0.05). The postoperative complication rate in the study group (3.77%) was lower than that in the control group (15.09%; P < 0.05). CONCLUSIONLCP + T-type steel plate internal fixation has advantages in terms of minimizing trauma and enabling early postoperative functional exercise, promoting functional recovery and lower limb weight-bearing, and reducing postoperative complications.

Patella cryo-free technique with recycled frozen autograft reconstruction preserves extensor mechanism for proximal tibial malignancy.

We designed a patella cryo-free method to protect patella from cryoinjury during recycled frozen bone-prosthesis-composite reconstruction for proximal tibial malignancy. This study aimed to use animal model to ensure safety and efficacy of this method and reported our clinical outcomes. Six swine proximal tibias along with patella and patellar tendon were harvested and dived into group A (n = 3, traditional patella freezing) and group B (n = 3, patella cryo-free). Temperature curve measurement, histological analysis, and TUNEL assay were performed in both groups. Clinically, we retrospectively reviewed 23 patients with proximal tibia malignant bone tumor (13: traditional patella freezing method; 10: patella cryo-free method). The clinical and functional outcomes were reported and compared in both groups. Temperature curve of the group B showed that ideal therapeutic temperature (<-60°C) required to kill tumor cells can be achieved in the proximal tibia while the innocent patella can be kept in room temperature at all time. Histological analysis showed better preservation of the cartilage tissue in patella of group B. TUNEL assay showed significantly more apoptotic cells in the frozen tibia of both groups and frozen patella of group A. When reviewing our clinical results, less complication of the patella as well as better functional preservation were found in patients subjecting to patella cryo-free method. No local recurrence was observed in either group. Patellar cryo-free technique could protect patella from cryoinjury during freezing and therefore preserve more extensor functions for patients with proximal tibial malignant bone tumors.

Donor Site Morbidity of Calcaneal, Distal and Proximal Tibial Cancellous Autografts in Foot and Ankle Surgery: A Systematic Review and Meta-Analysis of 2296 Grafts

Category:OtherIntroduction/Purpose:Non-union of foot and ankle arthrodesis sites has been associated with revision surgery, morbidity and increased healthcare costs, so many surgeons elect to augment the fusion site with autologous bone grafts to improve union.While iliac crest autografts are considered the historical gold standard, other donor sites distal in the lower extremity such as calcaneus, proximal and distal tibia have been successfully used in foot and ankle surgery. This study aims to report on the safety and donor site morbidity of distal lower extremity (calcaneal, proximal and distal tibial) bone autografts. We summarized the findings in a comprehensive infographic illustration. We are unaware of any similar meta-analyses to date.Methods:Following the PRISMA guidelines, 2 independent investigators searched several databases in December 2020 using the following keywords and their synonyms: ('Bone graft', 'donor site morbidity', 'calcaneal graft', 'Proximal tibia graft', and 'distal tibia graft'). Besides, the reference lists from previous review articles were searched manually for eligible studies. The primary outcomes of interest were (1) Chronic pain, (2) Fracture and (3) infection whereas the secondary outcomes were (1) neurological complications, (2) sensory disturbance and hypertrophic scars, (3) other complications such as shoe-wear difficulties and gait disturbance. Inclusion criteria were: studies on complications and adverse events of lower extremity bone autografts (calcaneal, proximal tibial, and distal tibial bone autografts) reporting at least one desired outcome. Studies not reporting any of the outcomes of interest or if the full text is not available in English were excluded. Studies reporting on bone marrow aspirate or autografts for non-orthopedic indications were also excluded.Results:After removal of duplicates, 5981 studies were identified. After screening, 85 studies remained for full-text assessment, and 15 studies qualified for the meta-analysis with a total of 2296 bone grafts.1557(67.8%) were calcaneal grafts, 625 (27.2%) were proximal tibial grafts, and 114 (5%) were distal tibial grafts. The mean age of all patients was 52.43+-16 [CI=51.77-53.08] years.The mean follow-up duration was 1.86+-1.70[CI=1.79-1.93] years. The primary surgery was reported for 2129 grafts(92.7%).Out of those, foot and ankle procedure represented 97.4% of the procedures. In calcaneal bone grafts, there were 28 cases of chronic pain [1.97%,CI:1.10-2.50%, I2=66%], 5 fractures [0.32%,CI:0.10-0.60%, I2=0%], 20 sural neuritis [1.28%,CI:0.70-1.80%, I2=0%), and no wound infections. In proximal tibial grafts there were 13 cases of chronic pain [2.08%,CI:1.01-3.2%, I2=34.5%], 1 fracture [0.16%,CI:0.10-0.50%, I2= 0%], and 3 superficial wound infections [0.48%,CI:0.10-1.01, I2=0%]. In the distal tibial grafts there were no cases of chronic pain or wound infections, 1 fracture [0.90%,CI:0.80-2.6%,I2=0%], and 5 saphenous neuritis [4.5%,CI: 0.70- 8.40%,I2=65%].Conclusion:Calcaneal, distal tibial, and proximal tibial bone autografts are safe with a low rate of overall and major complications. We report an overall complication rate of 6.8%, which is less than half of that previously reported for iliac crest grafts. The authors recommend using distal lower extremity grafts for foot and ankle primary surgeries instead of iliac crest grafts when indicated. Clinical trials with large sample sizes are required.

Prediction of Distal Femur and Proximal Tibia Bone Mineral Density From Total Body Dual Energy X-Ray Absorptiometry Scans in Persons with Spinal Cord Injury

Bone density decreases rapidly after spinal cord injury (SCI), increasing fracture risk. The most common fracture sites are at the knee (i.e., distal femur or proximal tibia). Despite this high fracture incidence, knee-specific scans for bone density using dual x-ray absorptiometry (DXA) were not available until 2014 and are still not routinely used in clinical practice today. This has made it difficult to determine the rehabilitation efficacy and hindered understanding of the long-term changes in knee areal bone density. The purpose of this investigation was to compare areal bone mineral density values for the knee from both total-body and knee-specific DXA scans in persons with SCI. A total of 20 participants (16 males) >1 yr-post spinal cord injury received two DXA scans; a total-body scan and a knee-specific scan. Standardized methods were used to create regions of interest to determine bone density of four regions – the epiphysis and metaphysis of the distal femur and proximal tibia – from the total-body scan. Linear regressions and Bland-Altman analyses were conducted to determine the correlation (r2) and agreement (mean bias ± 95% level of agreement) respectively between the two scan types for each region. Linear regression analyses showed strong significant (p < 0.001) relationships between the two scan types for the distal femur epiphysis (r2 = 0.88) and metaphysis (r2 = 0.98) and the proximal tibia epiphysis (r2 = 0.88) and metaphysis (r2 = 0.99). The mean bias ± 95% level of agreement were distal femur epiphysis (0.05 ± 0.1 g/cm2) and metaphysis (0.02 ± 0.04 g/cm2); proximal tibia epiphysis (-0.02 ± 0.1 g/cm2) and metaphysis (0.02 ± 0.03 g/cm2). Results suggest knee-specific bone density can be assessed using a total-body DXA scan. This may allow for more comprehensive use of DXA scans which would reduce the burden of multiple site-specific scans for persons with SCI and enable more widespread adoption of knee bone density assessment in this population.

Architecture of the cancellous bone in human proximal tibia based on P45 sectional plastinated specimens.

To reveal differences in the pattern of trabecular architecture in the epiphysis and metaphysis of the proximal tibia. The trabecular architecture of the proximal tibia was observed in 27 P45 plastinated knee specimens. In the medial and lateral condyles, under the articular cartilage surrounded by the medial or lateral meniscus, the cancellous bone is formed by thick and dense trabecular bands, which run longitudinally in the epiphysis and then pass through the epiphyseal line to terminate on the slanted cortex of the metaphysis. In the intercondylar eminence, the trabeculae are arranged basically in a network. In the central portion of the tibial metaphysis, cancellous bone consists of fine arcuate trabeculae, which extend to the anterior and posterior cortices, respectively. These trabeculae are intersected sparsely and form trusses over the medullary cavity. Near the areas of attachment of the iliotibial tract, tibial collateral ligament, anterior and posterior cruciate ligaments, and patellar ligament, the cancellous bone is locally reinforced with patchy trabeculae, dense radiating trabeculae, or two orthotropictrabecular bands. This study provides further accurate anatomical information on the trabeculae of the proximal tibia. The soft structures of knee joint, including the articular cartilage, menisci, and ligaments, and the slanted cortices of the metaphysis are important landmarks for the location of different arrangements of the cancellous architecture. The present results are beneficial for clinical diagnosis and treatment of pathologies of the knee joint, or the establishment of a finite element analysis model of the knee joint.

Proximal tibial bone loss in the first 2 years after unicondylar knee arthroplasty: Anatomical pattern, predictors and clinical correlation

BackgroundTibial stress fracture, anteromedial bone pain, and early subsidence could occur after unicondylar knee arthroplasty (UKA). The change in metaphyseal tibial bone density (MTBD) in the coronal and sagittal planes after UKA might be a contributing factor, but this has rarely been investigated. The aim of this study was to assess the regional and temporal change in MTBD in the coronal and sagittal planes in the first 2 years after UKA. MethodsPatients with fixed-bearing medial UKA were recruited. The change in MTBD in the first 24 months after UKA using digital radiological densitometry (DRD) was measured. Potential predictors and clinical correlations were analyzed. ResultsEighty-four cases (female 60%) were selected for review. The follow up time was 63 (±17) months. Anterior and medial regions had the largest proportion of cases with MTBD reduction (90–97%, P < 0.05). Reduction was largest at anterior and medial regions (21–29%, P < 0.05) and smallest at posterior and lateral regions (5–15%, P < 0.05). Maximal reduction occurred at 12 months for the medial region and 24 months for the anterior region. MTBDs of both regions were not significantly influenced by any confounding factors. Significant correlation was found between medial MTBD and Function Score at 6 months. ConclusionsBone loss in a zonal pattern occurs in the first 2 years after UKA with the largest loss in the anterior region below the tibial tray. It is not affected by body mass index, perioperative alignment, or angle of correction. This suggests a physiological response to trauma other than a mechanical response to the change in bone strain.

Tibial Tubercle Preserving Anterior Closing Wedge Proximal Tibial Osteotomy and ACL Tunnel Bone Grafting for Increased Posterior Tibial Slope in Failed ACL Reconstructions

Anterior cruciate ligament reconstruction (ACLR) failure is multifactorial, but it is known that increased posterior tibial slope (PTS) leads to a greater likelihood of ACLR failure. This technical note describes the senior author’s technique for performing an anterior closing wedge proximal tibial osteotomy, in which the osteotomy is made proximal to the tibial tubercle. This procedure is the first part of a staged surgery for patients with multiple failed ACLRs and increased sagittal plane PTS. Debridement of osteolytic reconstruction tunnels with bone grafting is also undertaken in preparation for a second-stage revision ACLR.

Unusual case of adult onset proximal tibia gram negative osteomyelitis presenting as septic arthritis knee: A Case report

Case: A 58-year-old male patient came walking to casualty with the sole complaint of proximal tibia bone pain of one week duration. The patient was treated symptomatically after proper evaluation. One week later the patient presented with features of septic arthritis and was treated with arthrotomy and lavage. Non resolution of symptoms lead to a repeat surgery which identified acute osteomyelitis which had progressed to septic arthritis. This was inferred retrospectively considering the evolution of the patient’s symptoms. Conclusion: A high index of suspicion should be kept in mind regarding the possibility of adjacent osteomyelitis in patients presenting with septic arthritis.

Evaluation of surgical technique of screws and bone cement in R and C tibial bone defects correction of primary Total Knee Arthroplasty

Objective: The use of screws and cement is a well–known technique for repairing proximal tibial bone defects during primary total knee arthroplasty (TKA). The purpose of this study was to summarize our experience of using of screws and cement for R and C tibial bone defects in primary TKA.

An Unusual Case of an Extensive Proximal Tibia Bone Defect Secondary to Complicated Cellulitis Managed by Unifocal Bone Transport Using an Ilizarov Fixator

Introduction Bone defects occur following bone loss secondary to trauma or due to infection. Extensive bone defects are usually seen in the former. It is unusual to have large defects in isolated osteomyelitis without prior history of any trauma. We are reporting a case with a bone defect of around 17 cm due to infectious aetiology and its management by unifocal bone transport using the Ilizarov ring fixator. Case Report The present report describes a 45-year-old gentleman with newly diagnosed diabetes mellitus who was initially admitted under general surgery for management of cellulitis and was later admitted under orthopedics for suspected osteomyelitis of left proximal tibia and septic arthritis of left knee. Serial debridement, prolonged antibiotic therapy and skeletal stabilization by a temporary joint spanning external fixator was applied to control the infection. The infection finally resolved after 6 weeks with a bone defect of approximately 17 cm. Options for reconstruction were discussed with the patient along with their pros and cons. Unifocal bone transport by ilizarov ring fixator was finalized with the patient’s consent with the aim of achieving a functional limb. Bone healing index was 1.17 months/cm. ASAMI scoring showed excellent bone result and good functional result. LEFS was 55/80. The lower scores were because of the fused knee. Conclusion To the best of the authors’ knowledge this is the largest defect secondary to infection without history of trauma which has been successfully treated by unifocal bone transport.

Proximal Tibia Bone Stiffness and Strength in HR-pQCT- and QCT-Based Finite Element Models.

Injury to the ACL significantly increases the risk of developing post-traumatic osteoarthritis. Following injury, considerable focus is placed on visualizing soft tissue changes using MRI, but there is less emphasis on the alterations to the underlying bone. It has recently been shown using high-resolution peripheral quantitative computed tomography (HR-pQCT) that significant reductions in bone quality occur in the knee post ACL-injury. Despite the ability of HR-pQCT to show these changes, the availability of scanners and computational time requirements required to assess bone stiffness and strength with HR-pQCT limit its widespread clinical use. As such, the objective of this study was to determine if clinical quantitative CT (QCT) finite element models (QCT-FEMs) can accurately replicate HR-pQCT FEM proximal tibial stiffness and strength. From FEMs of 30 participants who underwent both QCT and HR-pQCT bilateral imaging, QCT-FEMs were strongly correlated with HR-pQCT FEM stiffness (R2 = 0.79). When QCT-FEM bone strength was estimated using the reaction force at 1% apparent strain, strong correlations were observed (R2 = 0.81), with no bias between HR-pQCT FEMs and non-linear QCT-FEMs. These results indicate that QCT-FEMs can accurately replicate HR-pQCT FEM stiffness and strength in the proximal tibia. Although these models are not able to replicate the trabecular structure or tissue-level strains, they require significantly reduced computational time and use widely available clinical-CT images as input, which make them an attractive choice to monitor bone density, stiffness and strength alterations, such as those that occur post ACL-injury.

Ramp Lesion Subtypes: Prevalence, Imaging, and Arthroscopic Findings in 2156 Anterior Cruciate Ligament Reconstructions

Background: Ramp lesions are defined as a particular type of injury within the posterior horn of the medial meniscus and its meniscocapsular attachments. Five subtypes have been described: type 1, meniscocapsular lesion; type 2, partial superior lesion; type 3, partial inferior lesion or hidden type; type 4, complete tear in the red zone; and type 5, complete double tear. Purpose: (1) To determine the prevalence of different subtypes of ramp lesions in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). (2) To describe the characteristics of ramp lesions based on imaging and diagnostic arthroscopy. Study Design: Cross-sectional study; Level of evidence, 3. Methods: All patients who underwent arthroscopic ACLRs between November 2015 and November 2018 by 2 senior surgeons at 1 institution were evaluated retrospectively (1) to describe the subtypes of ramp lesions diagnosed intraoperatively using transnotch arthroscopic exploration of the posteromedial compartment and (2) to look for any factors significantly associated with these subtypes. The following parameters were studied: demographics; history and clinical findings including time between injury and surgery, side-to-side laxity, and pivot shift; lesions missed on magnetic resonance imaging (MRI) scans and medial proximal tibial bone contusion visible on MRI scans; and arthroscopic confirmation of ramp lesion (ie, prevalence), associated lateral meniscal tear, or medial chondral tear. Results: Out of 2156 primary or revision arthroscopic reconstructions, 334 ramp lesions were confirmed, giving a prevalence of 15.5%. The subtype distribution was as follows: type 1, 47.9%; type 2, 4.8%; type 3, 11.4%; type 4, 28.7%; type 5, 7.2%. Multivariate analysis showed that gross pivot shift was significantly associated with complete ramp tears (odds ratio, 4.8; 95% CI, 1.7-17.2). Hidden lesions (type 3, inferior partial tear in the red zone) were the most likely to be missed on preoperative MRI (45.9%). Conclusion: In a population undergoing ACLR, the prevalence of ramp lesions was 15.5%. Among the subtypes of ramp lesion, the most common was a meniscocapsular junction tear (type 1). Partial inferior tears (type 3) were the most likely to be missed on preoperative MRI scans. Gross pivot shift was significantly associated with complete ramp tears (types 1, 4, and 5).

Finding alternative sites for intraosseous infusions in newborns

AimIntraosseous (IO)-access plays an alternative route during resuscitation. Our study in preterm and term stillborns was performed to find alternative IO puncture sites beside the recommended proximal tibia. MethodsThe cadavers used were legal donations. 20 stillborns (mean: 29.2weeks, IQR 27.1–39.6) were investigated. Spectral-CT were analysed to calculate the diameter and circumferences of: i) proximal humerus ii) distal femur iii) proximal tibia iv) diaphyseal tibial. Contrast medium was applied under video documentation to investigate the drainage into the vascular system. ResultsIn term newborns, diameter of the cortex of the proximal humeral head is 12.1 ± 1.8 mm, distal end of the femur 11.9 ± 3.4 mm and the proximal tibial bone 12.0 ± 2.4 mm with cross-sectional diameter of 113.5 ± 19.7 mm2, 120.6 ± 28.2 mm2 and 111.6 ± 29.5 mm2, respectively. Regarding the preterm groups, there is a strong age-related growth in diameter and cross -sectional size. The diaphyseal area is the smallest in all measured bones with an age-dependent increase and is about half of that of metaphyseal diameters (proximal and distal) and about one third of that of metaphyseal cross sectional areas. The proximal femoral head region has the largest diameter of all measured bones with an egg-shaped formation with an extensive joint capsula. All investigated metaphyseal areas lack a clearly enclosed bone marrow cavity. Infusion of contrast medium into the distal femoral end and the proximal humerus head demonstrate the drainage of contrast medium into the central venous system within seconds. ConclusionProximal humeral head and distal femoral end might be alternative IO areas which may lead to further IO puncture sites in neonates.

Vancomycin bone and tissue concentrations following tibial intraosseous administration - evaluated in a porcine model.

Introduction. Systemic perioperative vancomycin may not provide sufficient prophylactic target-site concentrations in the prevention of prosthetic joint infections. Intraosseous vancomycin potentially provides high target-site concentrations. The objective of the present study was to evaluate the local bone and tissue concentrations following tibial intraosseous vancomycin administration in a porcine model. Methods. Eight pigs received 500 mg diluted vancomycin (50 mg/mL) through an intraosseous cannula into the proximal tibial cancellous bone. No tourniquet was applied. Microdialysis was applied for sampling of vancomycin concentrations in adjacent tibial cancellous bone, in cortical bone, in the intramedullary canal of the diaphysis, in the synovial fluid of the knee joint, and in the subcutaneous tissue. Plasma samples were obtained as a systemic reference. Samples were collected for 12 h. Results. High vancomycin concentrations were found in the tibial cancellous bone with a mean peak drug concentration of 1236 (range 28–5295) , which remained high throughout the sampling period. The mean (standard deviation) peak drug concentration in plasma was 19 (2) , which was obtained immediately after administration. Peak drug concentration, time to peak drug concentration, and area under the concentration–time curve were within the same range in the intramedullary canal, the synovial fluid of the knee, and the subcutaneous tissue. Conclusion. Tibial intraosseous administration of vancomycin provided high concentrations in tibial cancellous bone throughout a 12 h period but with an unpredictable and wide range of peak concentration. The systemic absorption was high and immediate, thus mirroring an intravenous administration. Low mean concentrations were found in all the remaining compartments.

Midterm Outcomes of Tantalum Metal Cones for Severe Bone Loss in Complex Primary and Revision Total Knee Arthroplasty.

BackgroundManaging severe periarticular bone loss poses a major challenge in complex primary and revision total knee arthroplasty (TKA). Impaction bone graft, structural allografts, metal augments, and mega prosthesis are some of the methods used to address major bone loss. Tantalum metal (TM) Cones (Zimmer, Warsaw, IN) were introduced as an alternative to address this cohort of patients. The advantages of these cones include excellent biocompatibility, high porosity with osteoconductive potential, and a modulus of elasticity between cortical and cancellous bone. In addition, it is bioactive and offers an intrinsically high friction fit.MethodsA cohort of 62 patients with severe distal femoral and proximal tibial bone loss were operated for primary and revision TKA between January 2007 and December 2014 and followed up for a mean period of 108.5 months (range: 60-156 months). Preoperative and postoperative range of motion and Knee Society score were documented. Postoperatively long leg X-rays were performed at each follow-up visit to determine osteointegration, evidence of loosening, and migration.ResultsThe range of motion and Knee Society score improved considerably from preoperative a value of 63.9 ± 13.9° and 52 ± 14.9 to 102.1 ± 9.9° and 76.1 ± 10.03, respectively, at the final follow-up visit in the primary cohort and 52.14 ± 13.3° and 38.1 ± 9.1 to 92 ± 8° and 68.5 ± 4.3, respectively, in the revision cohort. Serial radiographs demonstrated complete osteointegration of the TM cones at the final follow-up.ConclusionsOur study demonstrates excellent midterm survivorship of TM cones with predictable osteointegration and good outcomes (clinical and radiological) in treatment of severe femoral and tibial metaphyseal bone defects in complex primary and revision TKAs.

Finite element analysis of tibia bone

This research was directed towards a study of the lower limb of the human body through the 3D modelling and finite element analysis of the tibia. FEA is used to evaluate the stresses and displacements of human tibia bone under physiological loading. In this study, CT scan data of patients' tibia bone (healthy, broken tibia bone after one month and two months of surgery tibia bone) are used to develop 3D finite element models of the left proximal tibia bone, and average body weight applied on tibia bone. FEA is conducted to calculate the equivalent von Mises stress, maximum principal stress, total deformation and fatigue tool from the whole proximal tibia bone and comparing the results. These analysed results provide a great foundation for further studies of bone injury prevention, bone transplant model integrity and validity and subject-specific fracture mechanism as the results of three bones compared.

Correlation between computed tomography value of the proximal tibia and general bone mineral density

Correlation between computed tomography value of the proximal tibia and general bone mineral density

Treatment of 10-mm-Deep or Greater Uncontained Tibial Bone Defects in Primary Total Knee Reconstruction without Metal Augmentation: Autologous Oblique Structural Peg Bone and Cancellous Chip Bone Grafting.

BackgroudIn this study, we report satisfactory clinical and radiological outcomes after autologous oblique structural peg bone and cancellous chip bone grafting without metal augmentation, including the use of a metal wedge, block, or additional stem, for patients with ≥ 10-mm-deep uncontained medial proximal tibial bone defects in primary total knee replacement.MethodsThe study group included 40 patients with primary total knee replacement with ≥ 10-mm-deep uncontained tibial bone defects who underwent autologous oblique structural peg bone and cancellous chip bone grafting and were followed-up for at least 1 year. Tibial cutting was performed up to a depth of 10 mm from the articular surface of the lateral tibial condyle, after which the height and area of the remaining bone defect in the medial condyle were measured. The bone defect was treated by making a peg bone and chip bone using excised segments of the tibia and femur. In all cases, the standard tibial stem and full cemented fixation techniques were used without metal augmentation. Preoperative and final follow-up radiologic changes and clinical measures were compared, and prosthesis loosening and bone union were checked radiologically at final follow-up.ResultsThe mean depth of the bone defects was 10.9 mm, and the mean percentage of the area occupied by bone defects in the axial plane was 18.4%. The mean mechanical femorotibial angle was corrected from 19.5° varus preoperatively to 0.2° varus postoperatively (p < 0.002). There was no prosthesis loosening, and all cases showed bone union at the 1-year postoperative follow-up.ConclusionsEven in patients with uncontained tibial bone defects ≥ 10-mm deep in primary total knee replacement, if the defect occupies less than 30% of the cut surface, autologous oblique structural peg bone and cancellous chip bone grafting can be used to achieve satisfactory outcomes with a standard tibial stem and no metal augmentation.

QCT-FE modeling of the proximal tibia: Effect of mapping strategy on convergence time and model accuracy

Quantitative computed tomography (QCT) based finite element (FE) modeling, referred to as QCT-FE, has seen rapid growth and application for modeling bone mechanics. With this approach, varying bone material properties are set via experimentally-derived density-modulus equations. One challenge though associated with QCT-FE is to identify the appropriate mapping strategy for assigning elastic moduli to elements. The goal of this study was to evaluate different QCT-FE mapping strategies to identify the optimum approach with fastest convergence rate and highest accuracy. Four proximal tibial medial compartments were imaged using QCT and experimentally tested to characterize proximal tibial subchondral bone stiffness at four surface points, resulting in a total of 16 indentation measures. Three material mapping methods were analyzed: (1) constant-E where an average elastic modulus was assigned to each element; (2) node-based where the material properties were first mapped on nodes then interpolated to Gaussian integration points; and (3) element-based in which the material properties were directly assigned to Gaussian integration points. Different element sizes were assessed with edge-lengths ranging from 0.9 to 3 mm. Results indicated that all converged models showed similar coefficient-of-determination (R2) and normalized root-mean-square errors (RMSE%). Though, the constant-E and node-based methods converged with the element edge-length of 1.5 mm (prediction error of 4.8% and 2.5%, respectively) whereas the element-based method converged with a larger element having an edge-length 2.5 mm (error = 4.9%). In conclusion, the element-based method, with a larger element size, resulted in similar predictive accuracy, faster convergence and shorter run-times relative to the constant-E and node-based approaches. As such, we recommend the element-based method for future subject-specific QCT-FE modeling.