Tibial Valgus Research Articles

Open Wegde Tibial Osteotomy: New Approach and Advantages of the Technique

The tibial valgus osteotomy is a so-called conservative" surgical technique used in the treatment of knee osteoarthritis in the early stages of evolution, as opposed to non-conservative techniques such as knee prostheses. Internal knee osteoarthritis is promoted by an anomaly of the axis of the lower limb (genu varum). When there is an axis defect, the stresses are poorly distributed and the weight of the body is applied more on the internal side, accelerating the wear of the cartilage. When this is not too significant, we can propose to slow down its evolution by modifying the axis of the knee by an osteotomy. This is the tibial valgus osteotomy. This osteotomy can be performed in 2 different ways either by “opening” the internal part of the tibia (it is the tibial varus osteotomy by internal addition) or by “closing” its external part (external subtraction osteotomy). The choice of one or the other of these 2 operating techniques is up to each surgeon.

Long-Term Survival and Predictors of Failure of Opening Wedge High Tibial Osteotomy.

High tibial valgus osteotomy (HTO) is a widely accepted procedure indicated for varus knee with symptomatic osteoarthritis of the medial compartment. However, there is a lack of studies evaluating long term results of this procedure. The primary aim of this study was to evaluate the long-term survival of opening wedge high tibial osteotomy (HTO) for isolated osteoarthritis in the medial compartment of the knee. The secondary objective was to identify independent predictors of conversion to total knee arthroplasty (TKA). This is a long term retrospective study of 296 cases of open wedge HTOs performed at a single center (level of evidence IV) between January 2005 and August 2015. Opening wedge medial HTO was always performed after diagnostic arthroscopy. Eighty-three percent of the population (233 patients, 247 procedures) was followed up at a mean 11.6 years (6-17) by telephone interview, to evaluate the possible conversion to TKA. Mean age at the index operation was 42.8 years (range 15-70) and most patients were male (70%). Associated procedures (e.g., platelet rich plasma supplementation, microfractures, meniscectomy, etc.) were carried out at the time of the HTO in 80 (32%) cases. Survival of HTO and its association with age, sex, body mass index, smoking habit, preoperative severity of varus deformity, cartilage status at surgery, and associated procedures were evaluated. Kaplan-Meier and Cox regression analyses were performed. Thirty-three of the 247 HTOs (13.4%) were converted to knee replacement, with 86.6% of the original procedures surviving at a mean 12-year follow-up. Kaplan-Meier survival estimates at 17 years for HTO were 75.5% (95% confidence interval [CI] 66.7-84.3). There was significant difference (P < 0.001) in the 17-year survival rate between obese (55.5%; 95% CI 35.3-75.6) and non-obese (79.7%; 95% CI 70.1-89.2) patients. The determinants of conversion to knee arthroplasty detected at multivariate Cox regression analysis were body mass index, severity of cartilage degeneration in the medial compartment (Outerbridge grade), and age. The long-term survival of open wedge HTO for osteoarthritis in the medial compartment of the knee is satisfactory. The risk of conversion to TKA is significantly increased in obese patients. Advanced age and severity of pre-existing cartilage damage may also contribute to the risk of conversion to TKA.

Correlation between tibial valgus deformity and aspect ratio of resected tibial surface in female Chinese patients undergoing total knee arthroplasty.

Morphology of the resected tibial surface is the reference for tibial component design, selection, and implantation in total knee arthroplasty (TKA). This comparative study sought to answer whether valgus deformity of the tibia would affect the morphology of the resected tibial surface in TKA. Thirty-one female Chinese patients with valgus tibias were retrospectively and consecutively identified from a single-center registration database. Thirty-one patients with well-aligned tibias were matched in terms of gender, height, and weight. Weight-bearing full-length radiographs and computed tomography images of the whole lower limb were obtained for every case. Tibial resection was mimicked perpendicular to the mechanical axis of the tibia in the frontal plane with 3° of posterior slope and a cut level individualized by the actual intraoperative cut. On the resected surface, mediolateral dimension (MLD), medial anteroposterior dimensions (mAPD), and lateral anteroposterior dimensions (lAPD) were measured, and aspect ratios (AR) were calculated. We compared the AR between the two groups. The aspect ratio of resected tibial surface positively correlated with tibial valgus alignment. Patients with valgus tibias had significantly smaller AR (MLD/mAPD) for the medial plateau (1.50 ± 0.06 vs. 1.54 ± 0.07, P = 0.032). However, the AR for the lateral plateau was similar between the two groups (1.63 ± 0.08 vs. 1.65 ± 0.07, P = 0.328). This difference in morphology of resected tibial surface between valgus and well-aligned tibias should be considered in tibial component design, as well as in the selection and placement of TKA implants for knees with valgus tibias.

Can radiological findings detect neuropathic pain in patients with osteoarthritis of the knee undergoing surgery?

The mechanism underlying neuropathic pain (NP) in osteoarthritis (OA) of the knee is not completely understood. This study aimed to investigate whether possible NP in patients with knee OA undergoing knee surgery is associated with specific radiological findings. This study included 197 patients who underwent knee surgery for symptomatic knee OA. Clinical evaluation was performed using the Central Sensitization Inventory (CSI), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and PainDETECT questionnaire. Radiological evaluation was performed using the hip-knee-ankle (HKA) angle, posterior tibial slope (PTS), varus and valgus laxities, and magnetic resonance imaging OA Knee Score (MOAKS). Radiological findings were compared between patients with possible and unlikely NP. Logistic regression analysis was performed to identify the predictive factors for NP. There were 163 and 34 patients with unlikely NP and with possible NP, respectively. The percentage of patients with CSI score ≥ 40 was significantly higher in the possible NP group than in the unlikely NP group (17.6% vs. 6.1%). Patients with possible NP had worse WOMAC scores than patients with unlikely NP. There were no significant positive associations between the possible NP and radiological findings in knee OA. Regression analysis showed no predictive factors for possible NP. Possible NP is not associated with specific radiological findings in knee OA. Patients with possible NP may mediate CS and experience more severe symptoms, including decreased knee function and lower quality of life, than patients with unlikely NP.

The AMADEUS score is not a sufficient predictor for functional outcome after high tibial osteotomy

PurposeThe Area Measurement And Depth Underlying Structures (AMADEUS) classification system has been proposed as a valuable tool for magnetic resonance (MR)-based grading of preoperatively encountered chondral defects of the knee joint. However, the potential relationship of this novel score with clinical data was yet to determine. It was the primary intention of this study to assess the correlative relationship of the AMADEUS with patient reported outcome scores in patients undergoing medial open-wedge high tibial valgus osteotomy (HTO). Furthermore, the arthroscopic ICRS (International Cartilage Repair Society) grade evaluation was tested for correlation with the AMADEUS classification system.MethodsThis retrospective, monocentric study found a total of 70 individuals that were indicated for HTO due to degenerative chondral defects of the medial compartment between 2008 and 2019. A preoperative MR image as well as a pre-osteotomy diagnostic arthroscopy for ICRS grade evaluation was mandatory for all patients. The Knee Osteoarthritis Outcome Score (KOOS) including its five subscale scores (KOOS-ADL, KOOS-QOL, KOOS-Sports, KOOS-Pain, KOOS-Symptoms) was obtained preoperatively and at a mean follow-up of 41.2 ± 26.3 months. Preoperative chondral defects were evaluated using the AMADEUS classification system and the final AMADEUS scores were correlated with the pre- and postoperative KOOS subscale sores. Furthermore, arthroscopic ICRS defect severity was correlated with the AMADEUS classification system.ResultsThere was a statistically significant correlation between the AMADEUS BME (bone marrow edema) subscore and the KOOS Symptoms subscore at the preoperative visit (r = 0.25, p = 0.04). No statistically significant monotonic association between the AMADEUS total score and the AMADEUS grade with pre- and postoperative KOOS subscale scores were found. Intraoperatively obtained ICRS grade did reveal a moderate correlative relation with the AMADEUS total score and the AMADEUS grade (r = 0.28, p = 0.02).ConclusionsThe novel AMADEUS classification system largely lacks correlative capacity with patient reported outcome measures in patients undergoing HTO. The MR tomographic appearance of bone marrow edema is the only parameter predictive of the clinical outcome at the preoperative visit.

Geometrical analysis of the opening gap after tibial condylar valgus osteotomy for proper hinge point selection

Preoperative deformity and hinge position are associated with the magnitude of the gap opening during corrective osteotomy. A larger opening gap angle is associated with a higher risk of complications. This cross-sectional study sought to identify a suitable hinge position that results in the smallest opening angle during tibial condylar valgus osteotomy (TCVO). The data of 66 arthritic knees treated by TCVO were included, comprising 16 knees with the hinge points selected medial to the center (group M), 21 knees with the hinge points selected at the center (group C), and 29 knees with the hinge points selected lateral to the center of the intercondylar eminence (group L). The opening gap angles and the correction amounts of the medial proximal tibial angle (ΔMPTA) were compared among the 3 groups to identify the preliminary relationship between the hinge positions and the opening gap angle. A simplified geometric model with the hinge positions selected at the medial beak, the center, and the lateral beak of the intercondylar eminence was constructed to simulate the realignment process. Several anatomical points were allocated as Cartesian coordinates. The opening gap angle with different hinge positions was mathematically formulated with MATLAB (MathWorks, Natick, MA, USA). The average ΔMPTAs were 9.4±2.9°, 9.4±3.5°, and 9.3±3.0° in groupsL, C, and M, respectively. The opening angle of the osteotomy gap was the largest in groupM and the smallest in group L (29.7±11.1° and 16.9±5.3°; P<0.01). The comparison of the opening angle per the ΔMPTA revealed a similar pattern. The simulated realignment process indicated that the hinge point at the lateral beak of the intercondylar eminence led to the smallest opening angle. The opening angle during TCVO was mathematically derived in terms of the ΔMPTA, the position of the intersection of the pre- and postoperative joint lines, and the position of the hinge point. The hinge point at the lateral beak of the intercondylar eminence results in the smallest opening angle and may be suitable for TCVO.

Clinical study of a new type of telescopic rod for the treatment of congenital pseudarthrosis of the tibia in children.

The purpose of this study was to investigate the initial efficacy of a new telescopic rod in the treatment of congenital pseudarthrosis of tibia (CPT) in children. A new type of telescopic rod for children was designed and its clinical results were evaluated. There were nine cases of CPT on the right and six cases on the left; there were six females and nine males. The average age at operation was 35.5 months. There were 12 cases with neurofibromatosis type 1 and 4 cases with proximal tibial dysplasia. The initial healing of tibial pseudarthrosis, proximal tibial valgus deformity, tibial length, ankle valgus, ankle function, and intramedullary rod displacement were evaluated during follow-up. All 15 cases were followed up for an average of 18.2 months, 14 cases achieved initial healing, with an average healing time of 4.3 months. Ten cases had unequal lengths of the tibia, with an average of 0.9 cm. Proximal tibial valgus occurred in seven cases and ankle valgus occurred in one child. The average range of motion of the ankle joint was 23° and the average plantar flexion was 42°. The average extension of the new telescopic rod was 1.6 cm. The displacement of the telescopic rod occurred in seven cases, there was no epiphyseal plate tethering and re-fracture. The new children's telescopic rod has a reasonable design and can extend with the growth of tibia. There are no complications of epiphyseal plate tethering and re-fracture. It provides a new choice of intramedullary fixation for the treatment of CPT.

Lateral Gradual Opening Osteotomy of the Tibia With Monolateral External Fixator for Correcting the Valgus Deformity of the Tibia

The valgus deformity in the tibia requires correction because it places increased pressure on the lateral compartment of the knee, intensifying the degenerative process. Correction strategies are diverse and depend on patient profile, age, and soft-tissue conditions as well as the orthopaedic surgeon’s experience with different surgical materials. Deformity size and location are the primary factors contributing to material and shape choice, whether gradual or acute. The only gradual correction approach involves the use of a monolateral or circular external fixator. This is the only indication for correction in cases of excellent deformity, soft-tissue involvement, and a history of bone infection. This study aimed to present a gradual correction technique for tibial valgus deformity using a monolateral external fixator as well as its postoperative follow-up. This technique has the advantages of greater patient acceptance, lighter assembly, and briefer distraction owing to the use of a single piece as well as the ability of the operated limb to bear a load the day after the surgical procedure and dynamic outpatient follow-up.

Facteurs extra articulaires du tibia et du fémur influençant l’équilibre du genou dans les prothèses totales de genou implantées selon un alignement mécanique

PurposeAlthough the joint gap distance and compartment loading of the knee are different parameters for obtaining balanced knees in patients with total knee arthroplasty (TKA), the extent to which a balanced knee is achieved in patients with mechanically aligned TKA (MA-TKA) is unclear. This study aimed to investigate the anatomical factors that affect the ligament balancing in MA-TKA according to a gap balancing technique by measured resection technique. MethodsThe relationship between compartment loading, gap distance, and lower limb alignment was analysed in forty-three patients who underwent navigation-assisted MA-TKA with the minimum soft-tissue release. Radiographic parameters included hip-knee-ankle (HKA) angle, femorotibial angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, posterior tibial slope, varus and valgus joint line convergence angle, femoral valgus angle, femoral shaft curve, and tibial shaft curve (TSC). ResultsThe postoperative HKA angle was 0.4°±1.5°, with one coronal alignment outlier (2.3%). The gap distance showed four unbalanced knees for extension (9.3%) and flexion (9.3%), whereas the compartment loading identified 17 unbalanced knees (39.5%) at extension, 8 (18.6%) at 45° flexion, 7 (16.2%) at 90° flexion, and 10 (23.2%) at full flexion in MA-TKA. Mediolateral differentials of compartment loading correlated with femoral valgus angle (0°, 45°, and 90° flexion), mLDFA (45° and 90° flexion), and TSC (45° and 90° flexion). Femoral valgus angle and TSC were risk factors of the mediolateral differentials of compartment loading. ConclusionExtra-articular factors of femoral valgus angle, mLDFA, and TSC were associated with the mediolateral imbalance of compartmental loading, suggesting there is a limit to obtaining balanced knees in MA-TKA due to these unadjustable extra-articular factors. Level of evidenceIV, therapeutic case series.

Tibial condylar valgus osteotomy for the treatment of intra-articular varus deformity of the knee.

The increasing incidence and distribution of primary and post-traumatic knee osteoarthritis (OA) in the young, active population has renewed interest in joint-preserving procedures. High tibial osteotomy (HTO) represents the most common treatment for medial knee OA associated with varus tibial deformity. However, deformities may also be related to intra-articular defects that an extra-articular procedure could not correct. The tibial condylar valgus osteotomy (TCVO) represents an intra-articular surgical technique for treating advanced medial knee OA with lateral joint subluxation. Currently, only a few papers with small samples and limited follow-up report the use of TCVO for the treatment of intra-articular deformities. Indications and operative techniques are various and not standardized. After an extensive search of PubMed, Scopus and Cochrane library, the main purpose of this paper is to summarize and discuss the indications, surgical techniques, and outcomes of intra-articular osteotomies while also reporting the preoperative planning and surgical procedure performed at our institution. These characteristics allow earlier weight-bearing and faster complete recovery. TCVO is an effective procedure to correct lower limbs' intra-articular defects from degenerative conditions developmental and post-traumatic deformities. This surgical technique, working at the intra-articular level, leads to some benefits related to restoring joint congruence and stability by realigning the axis of the lower limb and reducing the lateral joint subluxation. Moreover, the improved valgisation and lateralization of the mechanical axis and the limitation of the osteotomy to the medial condyle led to a better load distribution to the not osteotomy-involved compartment.

Graft Diameter Should Reflect the Size of the Native Anterior Cruciate Ligament (ACL) to Improve the Outcome of ACL Reconstruction: A Finite Element Analysis.

The size of the anterior cruciate ligament (ACL) often varies between individuals, but such variation is not typically considered during ACL reconstruction (ACLR). This study aimed to explore how the size of the ACL affects the selection of a suitable graft diameter. A finite element model of a human knee was implanted with intact ACLs of different dimensions (0.95, 1 and 1.05 times the size of the original ACL) and with grafts of different diameters, to simulate ACLR (diameter 7.5–12 mm in 0.5 mm increments). The knee models were flexed to 30° and loaded with an anterior tibial load of 103 N, internal tibial moment of 7.5 Nm, and valgus tibial moment of 6.9 Nm. Knee kinematics (anterior tibial translation (ATT), internal tibial rotation (ITR) and valgus tibial rotation (VTR)) and ligament forces were recorded and compared among the different groups. The results showed that, compared with the intact knee, a graft diameter of 7.5 mm was found to increase the ATT and VTR, but reduce the graft force. Increasing the graft diameter reduced knee laxity and increased the graft force. A 10% increase in the size of the ACL corresponded to a 3 mm larger graft diameter required to restore knee stability and graft force after ACLR. It was concluded that the graft diameter should be selected according to the dimensions of the native ACL, for better restoration of knee functionality. This study may help to improve the clinical treatment of ACL ruptures.

Comparison of Hindlimb Conformation in Cats with and without Medial Patellar Luxation.

Medial patellar luxation (MPL) is the most common developmental cause of hindlimb lameness in cats. The association between femoral and tibial conformation and MPL measured on computed tomography (CT) has not been reported in cats. The aims were to report femoral and tibial conformation in cats with and without MPL and to report normal femoral and tibial angles. Angle of inclination of femoral neck (AI), anatomical lateral distal femoral angle (aLDFA), femoral trochanteric angle (FCT), angle of anteversion of femoral neck (AA), distal and proximal anteversion angle (DAA/PAA), overall tibial valgus (TV), tibial torsion (TT), tibial tuberosity displacement (TTD) and trochlear depth:patellar thickness ratio (T:P) were measured by three observers on CT of cats with and without MPL. Comparisons were made between groups. Inter-observer intraclass correlation coefficient (ICC) was calculated. Sixteen cats were recruited: eight control and eight with MPL. The aLDFA, PAA, TT, TTD and T:P were significantly less in cats with high-grade MPL. The AI, FCT, AA, DAA and TV were not significantly different. A high correlation was shown with inter-observer ICC in 33.33% and good correlation in 26.67% when comparing measurements between observers. This study suggests that cats with high-grade MPL have decreased TT, TTD and T:P and may require tibial tuberosity transposition and femoral trochleoplasty. The PAA, TT and aLDFA were decreased, although clinical significance may vary and these cats may not require correctional osteotomies. Results should be interpreted with caution as high/good levels of inter-observer ICC occurred in less than two-thirds of cases between observers.

Can the MRI based AMADEUS score accurately assess pre-surgery chondral defect severity according to the ICRS arthroscopic classification system?

PurposeThe AMADEUS (Area Measurement And DEpth and Underlying Structures) scoring and grading system has been proposed for the MRI based evaluation of untreated focal chondral defects around the knee. The clinical practicability, its correlation with arthroscopically assessed grading systems (ICRS – International Cartilage Repair Society) and thereby its clinical value in terms of decision making and guiding prognosis was yet to determine.MethodsFrom 2008 to 2019 a total of 89 individuals were indicated for high tibial valgus osteotomy (HTO) due to tibial varus deformity and concomitant chondral defects of the medial compartment of the knee. All patients received a preoperative MRI (1.5 Tesla or 3.0 Tesla) and pre-osteotomy diagnostic arthroscopy. Chondral defects of the medial compartment were scored and graded with the MRI based AMADEUS by three independent raters and compared to arthroscopic defect grading by the ICRS system. Interrater and intrarater reliability as well as correlation analysis with the ICRS classification system were assessed.ResultsIntraclass correlation coefficients for the various subscores of the AMADEUS showed an overall good to excellent interrater agreement (min: 0.26, max: 0.80). Intrarater agreement turned out to be substantially inferior (min: 0.08, max: 0.53). Spearman correlation revealed an overall moderate correlative association of the AMADEUS subscores with the ICRS classification system, apart from the defect area subscore. Sensitivity of the AMADEUS to accurately identify defect severity according to the ICRS was 0.7 (0.69 for 3.0 Tesla MRI, 0.67 for 1.5 Tesla MRI). The mean AMADEUS grade was 2.60 ± 0.81 and the mean ICRS score 2.90 ± 0.63.ConclusionsOverall, the AMADEUS with all its subscores shows moderate correlation with the arthroscopic chondral grading system according to ICRS. This suggests that chondral defect grading by means of the MRI based AMADEUS is well capable of influencing and guiding treatment decisions. Interrater reliability shows overall good agreement.

An Anatomic Study of the Proximal Tibial Epiphysis With Relevance to Percutaneous Epiphysiodesis Using Transphyseal Screws (PETS).

Percutaneous epiphysiodesis using transphyseal screws (PETS) is a common procedure to correct lower extremity limb-length discrepancies in the pediatric population. A potential complication of this procedure is development of tibial valgus deformity, which may occur secondary to decreased screw purchase in the thinner medial proximal tibial epiphysis. The thickness of the proximal tibial epiphysis has not yet been well quantified, which was the aim of this study. Three-dimensional surface scans of 32 cadaveric proximal tibial epiphyses in specimens aged 3 to 17 years old were obtained and computer modeling software was utilized to measure the thickness of the proximal tibial epiphysis at 20 standardized potential screw insertion points according to a generated 5×4 map. When normalized to the total width of the proximal tibial epiphysis, the lateral side is thicker compared with the medial side. The positions with the greatest thickness are located at the midline in the sagittal plane and 33% of the total physeal width away from the medial and lateral edges in the coronal plane (0.265 and 0.261 normalized thickness, respectively). The proximal tibial epiphysis is particularly thin 25% from the medial edge (normalized thickness range: 0.196 to 0.221). Multiple regression analysis revealed a significant relationship between increasing age and female sex with thinner normalized medial and lateral heights. During PETS, areas for greater screw purchase are located centrally in the sagittal plane and 33% of the total width away from the medial and lateral edges of the proximal tibial epiphysis in the coronal plane. Caution should be taken when inserting screws in the medial 25% of the proximal tibial epiphysis as it is thinner relative to the lateral edge, particularly in females. This study provides quantitative, anatomic data on the thickness of the proximal tibial epiphysis, which can direct screw placement during PETS for correcting limb-length discrepancies. These data may help lessen the risk of developing tibial valgus deformity although future clinical studies are necessary to fully evaluate this possibility.

Surgical and medical management in the treatment of proximal tibial metaphyseal fracture in immature dogs.

The purpose of this study was to report approaches to surgical and medical management of proximal tibial metaphyseal fractures (PTMF) and short-term case outcome. Medical records of immature dogs with PTMF were reviewed and data were collected including history, signalment and side affected. Data pertaining to surgical and medical management including radiographic evaluation and short-term complications were recorded. Forty-five dogs with a total of 47 PTMF identified and treated between 2007-2019 were included in this study. Six cases were managed with external coaptation alone. Forty-one cases were treated surgically with constructs including K-wires in different configurations, bone plate and screws, and external skeletal fixation. Of the cases managed conservatively, 4 developed complications, including bandage sores, diffuse osteopenia of the tarsus/metatarsus, and angular limb deformities. Surgical complications including pin migration necessitating removal, osteopenia, and screw placement in the proximal tibial growth plate or into the stifle joint were found in 16 cases. PTMF treated with surgery had a subjectively more predictable outcome compared to those treated with external coaptation alone. Conservative management may result in complications including development of excessive tibial plateau angle (TPA) as well as distal tibial valgus.

High Tibial Osteotomy Using the ‘Tomofix™’ Plating System: Short Term Outcomes in Young Adults

Proximal tibial valgus osteotomy is one of the treatment options for painful medial compartment osteoarthritis and varus deformity of the knee. The aim of our study was to determine and quantify how much osteotomy altered symptoms from medial compartment gonoarthrosis. In addition we aimed to establish whether the Tomofix plating system would permit early weight bearing and achieve union without the use of bone grafts. We prospectively analysed our experience with medial opening wedge high tibial osteotomy using the Tomofix plate.&#x0D; Thirty-five knees were included in the study. The mean age was 47 years (36-59 years). Mean duration of follow-up was 23 months (7-48 Months). All patients underwent medial opening wedge high tibial osteotomy using the Tomofix plating system. Data was recorded using the Oxford Knee score, the Knee Injury Osteoarthritis Outcome score and through review of pre and postoperative x-rays. Good outcomes were seen with statistically significant improvement of both scores.&#x0D; There were two delayed unions, the remainder united without requirement for graft. There was improvement, in Oxford and Knee injury osteoarthritis scores. Correction of mal-alignment was seen in all cases. Early weight bearing was found to be permissible without risk of adverse event.&#x0D; The Tomofix plate provided immediate stability and satisfactory healing of the osteotomy site without the need for bone graft. Good functional results were seen.

Biomechanical evaluation of combined proximal tibial osteotomy for varus knee osteoarthritis implanted novel designed plate system: Finite element analysis

BackgroundCombined proximal tibial osteotomy (CPTO) is an innovative and effective procedure for correcting varus knee osteoarthritis (VKOA) with intra- and extra-articular deformity. Here, we designed a novel internal fixation plate system for CPTO and assessed the biomechanical strength of the bone-implant. MethodsOur newly designed CPTO internal fixation plate system included a specialized plate shape, combination holes, locking screw holes, screw position, and size of fixation. The biomechanical performance of this plate system in CPTO treatment was compared via finite element analysis (FEA) to traditional Tomofix devices implanted in the opening-wedge high tibial osteotomy (OWHTO), tibial condylar valgus osteotomy (TCVO), and CPTO. ResultsThe tibial wedge stiffness and displacement after CPTO implantation of the novel internal plate fixation increased by 9.6%, which was -65% higher than the CPTO with the Tomofix system. The average stress of the bone, plate, and screws in the CPTO implanted the novel designed plate system compared to the Tomofix system decreased by 12.7%, 1.9%, and 20.3 %, respectively. The device maximum stress and wedge stiffness after CPTO with the novel plate system versus traditional OWHTO and TCVO with the Tomofix system were 255.7 MPa, 204 MPa, 130.4 MPa, and 678.9 N/mm, 660.3 N/mm, 1626.0 N/mm, respectively. ConclusionsThe novel internal fixation plate system usage during CPTO exhibited similar bone-implant biomechanical strength, compared to OWHTO, but with enhanced construct stability.

Combination of the Ilizarov Method and Intramedullary Fixation for the Treatment of Congenital Pseudarthrosis of the Tibia in Children: A Retrospective Observational Study

PurposeCongenital pseudoarthrosis of the tibia (CPT) is a rare disease in children, and its treatment remains a challenge for orthopedic surgeons. The purpose of this study was to evaluate treatment outcomes of patients with CPT treated by using the Ilizarov method combined with intramedullary fixation.MethodEighteen patients evaluated retrospectively from January 2009 to January 2020 were treated using the Ilizarov method combined with intramedullary fixation. Demographic data, clinical characteristics, and complications were all recorded and investigated during the period of follow-up. Ankle function was evaluated by the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores at the last follow-up.ResultThe average follow-up was 39.2 months (25–85 months) for all 18 patients. The mean age was 6.2 years (3.5–11.2 years). Fourteen (77.8%) patients had a primary bone union at the site of pseudarthrosis, while four obtained union after secondary surgical intervention. The mean duration of the Ilizarov method was 8.1 months (4.2–13.5 months). Eight (44.4%) patients had a pin-tract infection during treatment. Four (22.2%) patients had proximal tibial valgus with a mean angle of 12.1° (5–25°), while seven (38.9%) patients had ankle valgus deformities with a mean of 10.3° (5–20°). Eleven (61.1%) patients had an average 1.4 cm of limb length discrepancy (LLD) (0.6–3.1 cm) postoperatively. Five (27.8%) patients had refracture and recovered after a secondary surgery. At the last follow-up, the average postoperative AOFAS score was 72 (55–84).ConclusionThe Ilizarov method combined with intramedullary fixation is an effective method for the treatment of CPT, which can facilitate bony union and help to prevent refracture. Management of fibular pseudarthrosis is associated with functional outcomes. It is necessary to follow up until skeletal maturity and evaluate long-term clinical outcomes.

Extra-articular factors of the femur and tibia affecting knee balance in mechanically aligned total knee arthroplasty

PurposeAlthough the joint gap distance and compartment loading of the knee are different parameters for obtaining balanced knees in patients with total knee arthroplasty (TKA), the extent to which a balanced knee is achieved in patients with mechanically aligned TKA (MA-TKA) is unclear. This study aimed to investigate the anatomical factors that affect the ligament balancing in MA-TKA according to a gap balancing technique by measured resection technique. MethodsThe relationship between compartment loading, gap distance, and lower limb alignment was analysed in forty-three patients who underwent navigation-assisted MA-TKA with the minimum soft-tissue release. Radiographic parameters included hip-knee-ankle (HKA) angle, femorotibial angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, posterior tibial slope, varus and valgus joint line convergence angle, femoral valgus angle, femoral shaft curve, and tibial shaft curve (TSC). ResultsThe postoperative HKA angle was 0.4±1.5°, with one coronal alignment outlier (2.3%). The gap distance showed four unbalanced knees for extension (9.3%) and flexion (9.3%), whereas the compartment loading identified 17 unbalanced knees (39.5%) at extension, 8 (18.6%) at 45° flexion, 7 (16.2%) at 90° flexion, and 10 (23.2%) at full flexion in MA-TKA. Mediolateral differentials of compartment loading correlated with femoral valgus angle (0°, 45°, and 90° flexion), mLDFA (45° and 90° flexion), and TSC (45° and 90° flexion). Femoral valgus angle and TSC were risk factors of the mediolateral differentials of compartment loading. ConclusionExtra-articular factors of femoral valgus angle, mLDFA, and TSC were associated with the mediolateral imbalance of compartmental loading, suggesting there is a limit to obtaining balanced knees in MA-TKA due to these unadjustable extra-articular factors. Level of evidenceIV, therapeutic case series.

The 3-triangle method preserves the posterior tibial slope during high tibial valgus osteotomy: first preliminary data using a mathematical model

PurposeDespite much improved preoperative planning techniques accurate intraoperative assessment of the high tibial valgus osteotomy (HTO) remains challenging and often results in coronal over- and under-corrections as well as unintended changes of the posterior tibial slope. Noyes et al. reported a novel method for accurate intraoperative coronal and sagittal alignment correction based on a three-dimensional mathematical model. This is the first study examining preliminary data via the proposed Noyes approach for accurate intraoperative coronal and sagittal alignment correction during HTO.MethodsFrom 2016 to 2020 a total of 24 patients (27 knees) underwent HTO applying the proposed Noyes method (Noyes-Group). Radiographic data was analyzed retrospectively and matched to patients that underwent HTO using the conventional method, i.e., gradual medial opening using a bone spreader under fluoroscopic control (Conventional-Group). All operative procedures were performed by an experienced surgeon at a single orthopaedic university center.ResultsFrom the preoperative to the postoperative visit no statistically significant changes of the posterior tibial slope were noted in the Noyes-Group compared to a significant increase in the Conventional-Group (p = 0.01). Regarding the axial alignment no significant differences between both groups were observed pre- and postoperatively. The number of over- and under-corrections did not differ significantly between both groups. Linear regression analysis showed a significant correlation of the postoperative medial proximal tibial angle (MPTA) with the position of the weightbearing line on the tibial plateau.ConclusionThe 3-triangle method by Noyes seems to be a promising approach for preservation of the posterior tibial slope during HTO.