Medial Plateau Research Articles

Cartilage contact characteristics of the knee during gait in individuals with obesity.

Obesity increases the risk of knee osteoarthritis (OA). Knee joint contact characteristics have been thought to provide insights into the pathogenesis of knee OA; however, the cartilage contact characteristics in individuals with obesity have not been fully described. We conducted cartilage-to-cartilage contact analyses through high-precision fluoroscopy imaging with subject-specific magnetic resonance cartilage models. Twenty-five individuals with obesity were recruited for this study, and previously published data consisted of eight nonobese individuals who were used as the comparator group. In both groups, knees were imaged by a dual fluoroscopic imaging system during treadmill walking, and the tibiofemoral cartilage contact locations were analyzed and described on the tibial plateau in the medial-lateral (ML) and anterior-posterior (AP) directions and on femoral condyle surfaces using contact angles in the sagittal plane and deviation angles in a plane perpendicular to the sagittal plane. On the medial tibial plateau, the ML contact locations in the individuals with obesity were located more medially than in the nonobese group throughout the stance phase. The medial plateau AP contact locations in individuals with obesity showed a different pattern compared with the nonobese group. The ML contact excursions on the medial plateau in the individuals with obesity were larger than in the nonobese group. These findings suggest that obesity affects the contact location mainly in the medial compartment, which explains, in part, the high prevalence of medial knee OA in the obese population.

Biomechanical Characteristics of the Knee Joint during Gait in Obese versus Normal Subjects.

Knee osteoarthritis (OA) is a growing source of pain and disability. Obesity is the most important avoidable risk factor underlying knee OA. The processes by which obesity impacts osteoarthritis are of tremendous interest to osteoarthritis researchers and physicians, where the joint mechanical load is one of the pathways generally thought to cause or intensify the disease process. In the current work, we developed a hybrid framework that simultaneously incorporates a detailed finite element model of the knee joint within a musculoskeletal model to compute lower extremity muscle forces and knee joint stresses in normal-weight (N) and obese (OB) subjects during the stance phase gait. This model accounts for the synergy between the active musculature and passive structures. In comparing OB subjects and normal ones, forces significantly increased in all muscle groups at most instances of stance. Mainly, much higher activation was computed with lateral hamstrings and medial gastrocnemius. Cartilage contact average pressure was mostly supported by the medial plateau and increased by 22%, with a larger portion of the load transmitted via menisci. This medial compartment experienced larger relative movement and cartilage stresses in the normal subjects and continued to do so with a higher level in the obese subjects. Finally, the developed bioengineering frame and the examined parameters during this investigation might be useful clinically in evaluating the initiation and propagation of knee OA.

Morphometric Anatomy of the Tibia Plateau in Nigerians.

There are increasing cases of osteoarthritis and associated disabilities with age, hence the need for knee replacement to restore the anatomy and function of the knee. The objective of this study was to determine the dimensions of the tibial plateau in dry human tibias of Nigerians. This will serve as a guide for the tibia components during total knee replacement procedure. This study adopted the descriptive method of the quantitative design and utilized 133 dry tibias. Total transverse width, total anteroposterior length of intercondylar region, transverse widths of medial and lateral tibia plateaus, and anteroposterior length of the plateaus were measured in millimeter (mm). Statistical analysis of the data was done using mean (SD), t-test and correlation, with the aid of SPSS 23. Statistical significance was fixed at p<0.05. Statistically, the differences between the right and left parameters were not significant. The mean total transverse width was longer than the total anteroposterior length. The mean anteroposterior length of the medial tibia plateau was significantly longer than that of the lateral tibia plateau. The difference between the transverse width of both the medial and lateral tibia plateau was not statistically significant. This study showed that the tibial plateau dimensions can act as guiding tools to the orthopedic surgeon during a knee replacement procedure; and those involved in the fabrication of knee replacement prostheses for Nigerians. The physical anthropologists will also find the anthropometric data invaluable in population studies.

A rare case of hyperextended bicondylar tibia plateau fracture

Bicondylar tibia plateau fractures are a common injury in day-to-day practice, and categorization and treatment methods have been effectively described in the literature. The Hyperextension bicondylar tibia plateau (HEBTP) fracture is an uncommon fracture that is difficult to classify using standard classification techniques and has no set treatment strategy. Compressed anterior cortex, tension stress failure of the posterior cortex and loss of normal posterior slope of tibia plateau are all symptoms of HEBTP, which is produced by hyperextended high-energy trauma. HEBTP fracture is a kind of tibia plateau fracture which largely affects the tibial condyle' sagittal alignment. They account for fewer than 20% of all bicondylar injuries. As the knee has varus alignment and restraint of the knee's posterolateral capsule-ligamentous complex, there is asymmetric accumulation of force to the medial plateau resulting in a characteristic injury pattern that is often more severe on this side. Hence, we discuss a case of HEBTP managed with bicondylar plate and its functional outcomes. We present a case of a 44-year-old male patient who came to Acharya Vinoba Bhave Rural Hospital, Wardha with 5-day-old history of high-energy trauma to the right knee, with discomfort and swelling over the right knee and inability to bear weight over the right lower limb. The patient initially went to a local doctor and was treated conservatively with an above knee slab over his right lower limb before being sent to AVBRH for further treatment. On examination, there was extensive edema and varus deformity over the right proximal tibia. The tibia had substantial posterior sag, which is unusual in a tibial plateau fracture. Tenderness was present across the proximal one-third of the tibia, although there was no increase in local temperature. Range of motion in the knees was not possible. Clinically, there was a 10° varus deformity. The posterolateral ligament complex and collateral ligaments could not be evaluated. There were no symptoms of compartment syndrome present. There was no neurovascular injury. Distal circulation was intact. The differential diagnosis was posterolateral corner injury, posterior subluxation, or dislocation of the knee. To rule out the differentials, radiological imaging, X-ray, and a computed tomography scan were performed and the patient was diagnosed to have hyperextended bicondylar tibia plateau fracture. Open reduction and internal fixation with bicondylar plate osteosynthesis were used to treat the patient and extensive postoperative physiotherapy regimen was started. The patient was then followed up and results were recorded. The treatment for hyperextension tibia plateau fractures includes reducing fractures while healing critical ligament damage and restoring knee joint stability. If the tibial rim is depressed, the tibial rim should be rebuilt to restore the joint's stability. The features of anterior tibia fractures produced by knee hyperextension injuries are unknown at this time. For anterior tibia plateau fractures, there is very less unanimity on the best technique and fixing methods. The clinical dilemma of deciding how to decrease as well as cure the fractures of the anterior tibia plateau produced by the hyperextension injury remains unsolved. The treatment of hyperextension bicondylar tibia plateau fractures managed with open reduction and bicondylar plate osteosynthesis yields outstanding outcomes.

Change in angle of depressed medial tibial plateau following extra-articular mechanical realignment surgery in children with Blount's disease who presented late for treatment.

The aim of this study was to determine whether any change in degree of medial tibia plateau depression after extra-articular mechanical realignment surgery was observed in children with Blount's disease who presented late for treatment in their adolescence and young adulthood. We retrospectively reviewed the radiographic parameters of 22 patients (32 lower limbs) with Blount's disease who underwent gradual correction of deformity using a ring external fixator without surgical elevation of the depressed medial tibial plateau at a mean age of 15 (range 10-37) years. Preoperative and postoperative angles of depressed medial tibia plateau (ADMTPs) of the same patient were compared for any significant change. Normally distributed data were analysed using Student's t -test when comparing two groups or one-way analysis of variance when comparing more than two groups. Skewed data were analysed using Mann-Whitney test. After extra-articular mechanical alignment surgery, statistically significant improvements in medial tibial plateau depression were seen in the infantile ( P = 0.03) and juvenile ( P = 0.04) Blount's subgroups. Change in ADMTP was greater in patients who were operated on at age <17 years, before skeletal maturity ( P = 0.001). The improvement was likely due to ossification of unossified cartilage at the posteromedial proximal tibia and the remodelling potential of proximal tibia physis after mechanical realignment. Improvement of medial tibia plateau depression is possible after mechanical realignment without surgical hemiplateau elevation in cases of infantile and juvenile Blount's disease that present late for treatment, especially when the operation is performed before 17 years of age.

Femoral and Tibial Bony Risk Factors for Anterior Cruciate Ligament Injuries Are Present in More Than 50% of Healthy Individuals

Background: Anterior cruciate ligament (ACL) injuries are multifactorial events that may be influenced by morphometric parameters. Associations between primary ACL injuries or graft ruptures and both femoral and tibial bony risk factors have been well described in the literature. Purpose: To determine values of femoral and tibial bony morphology that have been associated with ACL injuries in a reference population. Further, to define interindividual variations according to participant demographics and to identify the proportion of participants presenting at least 1 morphological ACL injury risk factor. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computed tomography scans of 382 healthy participants were examined. The following bony ACL risk factors were analyzed: notch width index (NWI), lateral femoral condylar index (LFCI), medial posterior plateau tibial angle (MPPTA), and lateral posterior plateau tibial angle (LPPTA). The proportion of this healthy population presenting with at least 1 pathological ACL injury risk factor was determined. A multivariable logistic regression model was constructed to determine the influence of demographic characteristics. Results: According to published thresholds for ACL bony risk factors, 12% of the examined knees exhibited an intercondylar notch width <18.9 mm, 25% had NWI <0.292, 62% exhibited LFCI <0.67, 54% had MPPTA <83.6°, and 15% had LPPTA <81.6°. Only 14.4% of participants exhibited no ACL bony risk factors, whereas 84.5% had between 2 and 4 bony risk factors and 1.1% had all bony risk factors. The multivariate analysis demonstrated that only the intercondylar notch width (P < .0001) was an independent predictor according to both sex and ethnicity; the LFCI (P = .012) and MMPTA (P = .02) were independent predictors according to ethnicity. Conclusion: The precise definition of bony anatomic risk factors for ACL injury remains unclear. Based on published thresholds, 15% to 62% of this reference population would have been considered as being at risk. Large cohort analyses are required to confirm the validity of previously described morphological risk factors and to define which participants may be at risk of primary ACL injury and reinjury after surgical reconstruction.

Tibial Bone Quality in Former Bariatric Surgery Patients with Osteoarthritis.

This case-control study sought to determine if TKA patients with history of bariatric surgery exhibit altered microanatomy of subchondral bone quality in the tibial plateau compared to controls. With IRB approval, 41 bone samples were evaluated from 12 former bariatric surgery patients and 10 sex-, age-, weight-, height-, and BMI-matched controls. Patient-Reported Outcomes Measurement Information System (PROMIS) surveys were completed prior to TKA. Tibial plateau osteochondral tissues were recovered during the TKA procedure, and samples from the medial and lateral plateaus were dissected into 1 × 2cm sections, scanned using microcomputed tomography (µCT), and plastic-embedded for histologic sectioning/staining of undecalcified bone. Paired t tests with Bonferroni correction were performed to assess group differences. Female bariatric surgery patients had reduced osteoid/total area and greater osteoclast number asymmetry than female controls (p < 0.03). No differences were noted in µCT or histologic bone parameters between bariatric and control patients when the sexes were combined. Bariatric patients self-reported worse preoperative PROMIS pain interference and physical function scores than controls (p < 0.04). Similarities of subchondral bone between former bariatric surgery patients and matched controls indicate OA disease progression dominates the bone landscape in both patient groups.

Determining the Ratio of Wedge Height to Degree of Correction for Anterior Tibial Closing Wedge Osteotomies for Excessive Posterior Tibial Slope

Background: Anterior closing wedge osteotomy of the proximal tibia may be considered in revision anterior cruciate ligament (ACL) reconstruction surgery for patients with excessive posterior tibial slope (PTS). Purpose: (1) To determine the ratio of wedge thickness to degrees of correction for supratubercle (ST) versus transtubercle (TT) osteotomies for anterior closing wedge osteotomies and (2) to evaluate the accuracy of ST and TT osteotomies in achieving slope correction. Study Design: Controlled laboratory study. Methods: The computed tomography (CT) scans of 38 knees in 37 patients undergoing revision ACL reconstruction were used to simulate both ST and TT osteotomies. A 10° wedge was simulated in all CT models. The height of the wedge along the anterior tibia was recorded for each of the 2 techniques. The ratio of wedge height to achieved degree of correction was calculated. ST and TT osteotomies were performed on 3-dimensional (3D)–printed tibias of the 12 patients from the study group with the greatest PTS, after the desired degree of correction was determined. Pre- and postosteotomy slopes were measured for each tibia, and the actual change in slope was compared with the intended slope correction. Results: According to CT measurements, the ratio of wedge height to degree of correction was 0.99 ± 0.07 mm/deg for the ST osteotomy and 0.83 ± 0.06 mm/deg for the TT osteotomy (P < .001). When these ratios were used to perform simulated osteotomies on the twelve 3D-printed tibias, the mean slope correction was within 1° to 2° of the intended slope correction, regardless of osteotomy location (ST or TT) or whether slope was measured on the medial or lateral plateau. The ST technique tended to undercorrect and the TT technique tended to overcorrect. Conclusion: When anterior tibial closing wedge osteotomies were removed to correct excessive PTS, removing a wedge with a ratio of 1 mm of wedge height for every 1° of intended correction for an ST technique and a ratio of 0.8 mm to 1° for a TT technique resulted in overall average slope correction within 1° to 2° of the target. Clinical Relevance: The calculated ratios will allow clinicians to more accurately correct PTS when performing anterior closing wedge tibial osteotomy.

Radiographic detection of lateral plateau involvement in medial tibial plateau fractures (AO/OTA 41-B1.2, 1.3, 3.2 and 3.3).

To assess the accuracy of radiographs in detecting the lateral plateau involvement of medial tibial plateau fractures as well as describe the impact of CT on preoperative planning for this specific fracture morphology. Radiograph and CT imaging of patients with a Schatzker type IV tibial plateau fractures (AO/OTA 41-B1.2, B1.3h, B2.2. B3.2, and B3.3) between January 2013 and July 2017 were reviewed by three trauma fellowship-trained orthopedic surgeons to identify fractures of the medial condyle with an intact anterolateral articular surface. Lateral plateau involvement was identified in 16 (37%) radiographs and 26 (61%) CT images (p = 0.051). Radiographic detection of lateral plateau involvement demonstrated a sensitivity of 62% and specificity of 100%, and radiographs were able to predict the recommendation for surgical intervention for lateral plateau involvement with a positive predictive value (PPV) of 75% and a negative predictive value (NPV) of 60% compared to recommendations based on CT imaging. Radiographs predicted a need for a separate surgical approach with PPV of 63% and NPV of 70% when compared to recommendations based on CT images. Radiographs are reliable in ruling in lateral plateau involvement of medial plateau fractures, but occult lateral articular extension may only be identified in CT imaging for some cases. Surgical planning may be impacted by CT imaging for this fracture morphology, but further study is warranted to evaluate the correlation between preoperative planning and clinical outcomes. III.

Effect of warm-up and muscle fatiguing exercise on knee joint sounds in motion by vibroarthrography: A randomized crossover trial.

Vibroarthrography measures joint sounds caused by sliding of the joint surfaces over each other. and can be affected by joint health, load and type of movement. Since both warm-up and muscle fatigue lead to local changes in the knee joint (e.g., temperature increase, lubrication of the joint, muscle activation), these may impact knee joint sounds. Therefore, this study investigates the effects of warm-up and muscle fatiguing exercise on knee joint sounds during an activity of daily living. Seventeen healthy, physically active volunteers (25.7 ± 2 years, 7 males) performed a control and an intervention session with a wash-out phase of one week. The control session consisted of sitting on a chair, while the intervention session contained a warm-up (walking on a treadmill) followed by a fatiguing exercise (modified sit-to-stand) protocol. Knee sounds were recorded by vibroarthrography (at the medial tibia plateau and at the patella) at three time points in each session during a sit-to-stand movement. The primary outcome was the mean signal amplitude (MSA, dB). Differences between sessions were determined by repeated measures ANOVA with intra-individual pre-post differences for the warm-up and for the muscle fatigue effect. We found a significant difference for MSA at the medial tibia plateau (intervention: mean 1.51 dB, standard deviation 2.51 dB; control: mean -1.28 dB, SD 2.61 dB; F = 9.5; p = .007; η2 = .37) during extension (from sit to stand) after the warm-up. There was no significant difference for any parameter after the muscle fatiguing exercise (p > .05). The increase in MSA may mostly be explained by an increase in internal knee load and joint friction. However, neuromuscular changes may also have played a role. It appears that the muscle fatiguing exercise has no impact on knee joint sounds in young, active, symptom-free participants during sit to stand.

Tibial condylar valgus osteotomy (TCVO): Surgical technique and clinical results for knee osteoarthritis with varus deformity

Tibial condylar valgus osteotomy (TCVO) is an intra-articular proximal tibial osteotomy developed in 1989 and has since been used for the treatment of knee osteoarthritis (OA) associated with genu varum. This article describes the surgical technique and clinical results of TCVO. TCVO can be used for all grades of varus knee OA in patients of any age. he preoperative range of movement should be at least 90°. Preoperative screening showed varus-valgus instability due to an intra-articular deformity of the proximal tibia. Using intraoperative image intensification, a sagittally oriented “L”-shaped osteotomy is made from the medial to the tibial tuberosity to the center of the tibial plateau between the medial and lateral tibial spines. The separation of the osteotomy using the lamina spreader is gradually increased using an image intensifier guidance until the articular surface of the lateral tibial plateau comes in contact with the articular surface of the lateral femoral condyle. Adequate correction is indicated by parallelism of the lateral tibial plateau and a line tangential to the distal convexity of the lateral femoral condyle on an anteroposterior (AP) image and the elimination of the valgus instability with the knee in extended position. A “T”-plate (locking or non-locking plate or circular external fixator) is used to fix the osteotomy in the corrected position. Synthetic or autologous bone grafts can be used. We used the Japanese Orthopaedic Association score to evaluate the patient's function and also measured the %MAD, medial plateau opening angle, medial plateau angle, and lateral plateau opening angle on an AP view of the long length roentgenogram of the lower limb (standing position). The JOA score, radiologically measured values, and instability of the knee joint remarkably improved.

Wide variation in tibial slopes and trochlear angles in the arthritic knee: a CT evaluation of 4116 pre-operative knees

As surgeons continue to grapple with persistent issues of patient dissatisfaction post-TKA, the literature has focused on the coronal plane when considering alignment strategies but has largely ignored the sagittal and axial planes. The purpose of this retrospective observational cohort study is to evaluate variability in knee anatomy and alignment beyond the coronal plane and rationalise how this relates to existing arthroplasty alignment philosophies. 4116 knee CTs from 360 Knee Systems© database of arthritic pre-operative TKA patients were evaluated. Standardised bony landmarks were used in each CT to determine the hip-knee angle, medial proximal tibial angle, lateral distal femoral angle, medial plateau posterior tibial slope, lateral plateau posterior tibial slope, trochlea angle (TA) to distal femoral angle (TA-DFA) and TA to posterior condylar angle (TA-PCA). Analysis was performed to determine the distributions of each measure across the cohort population. Both the medial and lateral PTS ranged from 5° anterior to 25° posterior. 22.6% of patients had differential PTS greater than 5°. 14.5% have greater lateral PTS (mean difference to medial PTS of 4.8° ± 5.0°), whilst 31.0% have greater medial PTS (mean difference to lateral PTS of 5.7° ± 3.2°). 14% of TA-DFAs and 5.2% of TA-PCAs vary greater than 10°. This study demonstrates a wide variation in tibial slope, differential slope between the medial and lateral tibial plateau as well as variation in the trochlear geometry. There has been an overemphasis in the literature on coronal alignment, ignoring the considerable variability present in tibial and patellofemoral morphology. Existing arthroplasty techniques are based on assumptions that may not adequately address the anatomy of morphologic outliers and could lead to dissatisfaction. III-retrospective cohort study.

Medial meniscal ramp lesions in ACL-injured elite athletes are strongly associated with medial collateral ligament injuries and medial tibial bone bruising on MRI

PurposeMedial menisco-capsular separations (ramp lesions) are typically found in association with anterior cruciate ligament (ACL) deficiency. They are frequently missed preoperatively due to low MRI sensitivity. The purpose of this article was to describe demographic and anatomical risk factors for ramp lesions, and to identify concomitant lesions and define their characteristics to improve diagnosis of ramp lesions on MRI.MethodsPatients who underwent anterior cruciate ligament (ACL) reconstruction between September 2015 and April 2019 were included in this study. The presence/absence of ramp lesions was recorded in preoperative MRIs and at surgery. Patients’ characteristics and clinical findings, concomitant injuries on MRI and the posterior tibial slope were evaluated.ResultsOne hundred patients (80 male, 20 female) with a mean age of 22.3 ± 4.9 years met the inclusion criteria. The incidence of ramp lesions diagnosed at surgery was 16%. Ramp lesions were strongly associated with injuries to the deep MCL (dMCL, p < 0.01), the superficial medial collateral ligament (sMCL, p < 0.01), and a small medial–lateral tibial slope asymmetry (p < 0.05). There was also good correlation between ramp lesions and bone oedema in the posterior medial tibia plateau (MTP, p < 0.05) and medial femoral condyle (MFC, p < 0.05). A dMCL injury, a smaller differential medial–lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. MRI sensitivity was 62.5% and the specificity was 84.5%.ConclusionThe presence on MRI of sMCL and/or dMCL lesions, bone oedema in the posterior MTP and MFC, and a smaller differential medial–lateral tibial slope than usual are highly associated with ramp lesions visible on MRI. Additionally, a dMCL injury, a flatter lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. Knowledge of the risk factors and secondary injury signs associated with ramp lesions facilitate the diagnosis of a ramp lesion preoperatively and should raise surgeons’ suspicion of this important lesion.Level of evidenceDiagnostic study, Level III.

Gait risk factors for disease progression differ between non-traumatic and post-traumatic knee osteoarthritis

To examine if relationships between knee osteoarthritis (OA) progression with knee moments and muscle activation during gait vary between patients with non-traumatic and post-traumatic knee OA. This longitudinal study included participants with non-traumatic (n=17) and post-traumatic (n=18) knee OA; the latter group had a previous anterior cruciate ligament rupture. Motion capture cameras, force plates, and surface electromyography measured knee moments and lower extremity muscle activation during gait. Cartilage volume change were determined over 2 years using magnetic resonance imaging in four regions: medial and lateral plateau and condyle. Linear regression analysis examined relationships between cartilage change with gait metrics (moments, muscle activation), group, and their interaction. Measures from knee adduction and rotation moments were related to lateral condyle cartilage loss in both groups, and knee adduction moment to lateral plateau cartilage loss in the non-traumatic group only [β=-1.336, 95% confidence intervals (CI)=-2.653 to-0.019]. Generally, lower levels of stance phase muscle activation were related to greater cartilage loss. The relationship between cartilage loss in some regions with muscle activation characteristics varied between non-traumatic and post-traumatic groups including for: lateral hamstring (lateral condyle β=0.128, 95%CI=0.003 to 0.253; medial plateau β=0.199, 95%CI=0.059 to 0.339), rectus femoris (medial condyle β=-0.267, 95%CI=-0.460 to-0.073), and medial hamstrings (medial plateau; β=-0.146, 95%CI=-0.244 to-0.048). Findings indicate that gait risk factors for OA progression may vary between patients with non-traumatic and post-traumatic knee OA. These OA subtypes should be considered in studies that investigate gait metrics as risk factors for OA progression.

A Cadaveric Anatomical Study of the Relationship between Proximal Tibial Slope and Coronal Plane Deformity.

Medial proximal tibial angle (MPTA) and posterior proximal tibial angle (PPTA) are commonly used to characterize the geometry of proximal tibia and are important considerations in lower extremity realignment procedures and total knee arthroplasty. This study utilized a large cadaveric collection to explore relationships between tibial slope and coronal plane deformity of the tibia. We utilized 462 well-preserved skeletons (924 tibiae), excluding any with fracture or obvious rheumatologic or infectious findings. Custom cards were made with different sized arcs on the bottom surface, so that they could rest on the anterior and posterior aspects of the medial and lateral tibial plateaus of each bone to measure PPTA. Previously measured MPTA values for the same bones were also utilized. Multiple regression analysis was used to determine relationship between MPTA and medial and lateral PPTAs. The mean age was 56 ± 10 years, with 13% female and 31% African American (remainder Caucasian). The mean MPTA was 87.2 ± 2.4 degrees. The mean medial plateau PPTA was 81.5 ± 3.8 degrees and mean lateral plateau PPTA was 81.3 ± 3.7 degrees. Regression analysis found that MPTA was significantly associated with both medial and lateral PPTAs (standardized betas 0.197 and 0.146, respectively, p < 0.0005 for both). There was a significant correlation between lateral and medial PPTAs (r = 0.435, p = 0.03). The clinical significance of these findings warrants further investigation and emphasizes the importance of carefully assessing the sagittal plane when planning reconstruction of a tibia with varus or valgus deformity, particularly high tibial osteotomies.

Medial sided articular impaction in tibial plateau fractures

IntroductionTibial plateau fractures are a heterogenous group of injuries with a variable amount of articular injury and are commonly associated with lateral sided articular impaction. Previous work has focused on describing the morphology of tibial plateau fractures, but has neglected description of medial sided articular impaction. The aim of this investigation was to assess the morphology of medial sided articular impaction in tibial plateau fractures, with specific attention directed toward the frequency, location, size, and associated fracture patterns. MethodsSkeletally mature patients presenting to a Level I trauma center from 2008-2018 with a tibial plateau fracture (AO/OTA 41B-C) were identified retrospectively. Fractures were classified by AO/OTA and Schatzker type. Radiographs and computed tomography (CT) scans were reviewed to identify and localize medial sided articular impaction. The location and surface area of impaction was characterized by creating frequency diagram heat maps from axial CT scans. Descriptive statistics were performed using standard measures. ResultsOf the 1032 tibial plateau fractures included, 82 (7.9%) were noted to have medial sided articular impaction. Rate of impaction varied by fracture type (p = 0.03): Schatzker II, 2% (7 of 381); Schatzker IV, 21% (19 of 96); and Schatzker VI, 11% (56 of 524). Average total surface area of impaction was 9% of the total and 19% of the medial plateau area. Area of impaction varied by fracture type (p = 0.004): Schatzker II, 6% (95% confidence interval [CI], 4%−7%); Schatzker IV, 11% (95% CI, 9%−13%), and Schatzker VI, 9% (95% CI, 7%−11%). The area of impaction occurred primarily along the lateral aspect of the medial plateau in Schatzker II fractures, in the anteromedial quadrant of Schatzker IV fractures, and was evenly distributed across the medial plateau in Schatzker VI fractures. ConclusionsSurgeons should be aware that medial articular impaction is present in approximately 8% of tibial plateau fractures. Schatzker IV fractures are most likely to have medial impaction and a larger proportion of the joint surface involved in these injuries.

Patterns of Articular Cartilage Thickness in Pediatric and Adolescent Knees: A Magnetic Resonance Imaging–Based Study

PurposeTo establish normative values for articular cartilage thickness in pediatric and adolescent knees using magnetic resonance imaging (MRI) and investigate for any associations with age and skeletal maturity.MethodsMRI scans were analyzed in patients 7 to 18 years old without osteochondral lesions, chondral wear/pathology, intra-articular fractures, or history of knee surgery. Measurements of articular cartilage thickness at the patella (medial facet, lateral facet, median ridge), femur (medial condyle, lateral condyle, lateral trochlea), and tibia (medial plateau, lateral plateau) were made on axial, coronal, and sagittal MRI. Descriptive statistics were used to calculate mean cartilage thickness by age and sex. Analysis of variance with repeated measures, analysis of covariance, independent samples t test, and linear regression were performed to determine differences in mean cartilage thickness by anatomic location, sex, physeal status, and age, respectively.ResultsA total of 240 knee MRI scans were included. Articular cartilage was thickest at the patella and did not vary with age or skeletal maturity. On the femur, articular cartilage was thickest at the lateral trochlea with mean cartilage thickness of 4.4 ± 1.4 mm in male patients and 3.6 ± 1.3 mm in female patients (P < .001). Patients with open distal femoral physes had significantly thicker cartilage at the medial femoral condyle, lateral femoral condyle, and lateral trochlea compared to patients with closing/closed physes (P < .001). Linear regression analysis revealed a significant inverse association between cartilage thickness at the femur and age.ConclusionsIn pediatric and adolescent knees, articular cartilage is thickest at the patella, where it does not strongly correlate with age. In contrast, there is a strong inverse association between increasing age and articular cartilage thickness of the distal femoral condyles.Clinical RelevanceThe longitudinal reference data presented in this study can aid in pre-operative interpretation of knee cartilage under pathologic conditions in pediatric and adolescent patients.

Single-stage medial plateau elevation and metaphyseal osteotomies in advanced-stage Blount's disease: a new technique.

PurposeSurgical treatment in advanced-stage infantile Blount’s disease with medial plateau (MP) depression is challenging. Several osteotomies and fixation methods have been described with no established benchmark. We conducted this study to evaluate the efficacy and safety of a new single-stage technique for acute medial condyle elevation and metaphyseal osteotomies with internal fixation.MethodsA prospective case series of 19 consecutive patients (21 knees) with severe infantile Blount’s disease underwent a single-stage MP elevation and metaphyseal osteotomies, with internal fixation. The mean age was 10.3 years (8.2 to 13.6) and the mean follow-up was 5.1 years (3.2 to 8.3). The outcome measures included clinical and radiological parameters and patient-reported pediatric outcomes data collection instrument (PODCI) score.ResultsThe mean PODCI score improved significantly from 50% to 88%. The mean internal tibial torsion improved from -27° to 11°. All cases maintained full knee extension, no limitation in flexion range of movement and no signs of instability or lateral thrust gait. All the radiographic parameters improved significantly; the mean tibiofemoral angle improved from -29° to 7°, the metaphyseal-diaphyseal angle improved from 33.4° to 4.7° and the angle of depressed MP improved from 38.3° to 2.4° (p < 0.001). At the latest follow-up, no cases of deformity recurrence were identified, the final limb-length discrepancy was < 1 cm in all patients.ConclusionSingle-stage MP elevation and metaphyseal osteotomies with internal fixation significantly improved the clinical and radiographic parameters and PODCI score in advanced infantile Blount’s disease and precluded the use of external immobilization, with no evidence of deformity recurrence.Level of evidenceIV

Effects of the Medial Plateau Bearing Insert Conformity on Mid-Flexion Paradoxical Motion in a Posterior-Stabilized Total Knee Arthroplasty Design

BackgroundOne of the most common kinematic abnormalities reported for posterior-stabilized (PS) total knee arthroplasty (TKA) design is paradoxical anterior sliding during early and mid-flexion. PS TKAs have been designed such that the cam-post mechanism does not engage until later in flexion, making these implants vulnerable to anterior sliding during early and mid-flexion. The objective of this study is to investigate the biomechanical effect of increasing bearing conformity on a PS TKA. MethodsUsing a validated computational model of the knee joint, the sagittal conformity of the medial plateau of a PS TKA design was altered. Three scenarios were created and evaluated for mechanics: (1) baseline conformity, (2) increased conformity, and (3) decreased conformity. ResultsFrom full extension to approximately 70° of knee flexion, the medial condyle demonstrated minimal anterior sliding for the increased medial conformity design but revealed anterior sliding of 2 and 4 mm for the baseline and decreased conformity designs, respectively. After cam-post engagement, the medial condyle consistently rolled back for all 3 designs. The lateral condyle experienced consistent rollback throughout the entire flexion range for all 3 designs. However, femorotibial contact force was higher for the increased conformity design, peaking at 3.13 times body weight (×BW) compared to 3.0 × BW contact force for other 2 designs. ConclusionIncreasing medial conformity of the bearing insert appears to reduce mid-flexion sliding for PS TKA designs, although this comes at the expense of increased femorotibial forces. This could be due to kinematic conflicts that may be introduced with highly constraining designs.

Treatment of tibial plateau fractures with a novel fenestrated screw system for delivery of bone graft substitute.

The purpose of this study was to describe the incidence of subsidence in patients with AO/OTA 41 (tibial plateau) fractures which were repaired with a novel fenestrated screw system to used to deliver CaPO4 bone substitute material to fill the subchondral void and support the articular reduction. Patients with unicondylar and bicondylar tibial plateau fractures were treated according to the usual technique of two surgeons. After fixation, the Zimmer Biomet N-Force Fixation System®, a fenestrated screw that allows for the injection of bone substitute was placed and used for injection of the proprietary calcium phosphate bone graft substitute into the subchondral void. For all included patients, demographic information, operative data, radiographs, and clinic notes were reviewed. Patients were considered to have articular subsidence if one or more of two observations were made when comparing post-operative to their most recent clinic radiographs: > 2mm change in the distance between the screw and the lowest point of the tibial plateau, > 2mm change in the distance between the screw and the most superior aspect of the plate. Data were analyzed to determine if there were any identifiable risk factors for complication, reoperation, or subsidence using logistic regression. Statistical significance was set at p < 0.05. 34 patients were included with an average follow-up of 32.03 ± 22.52weeks. There were no overall differences between height relative to the medial plateau or the plate. Two patients (5.9%) had articular subsidence. Six patients (15.2%) underwent reoperation, two (6%) for manipulations under anaesthesia due to arthrofibrosis, and four (12%) due to infections. There were 6 (19%) total infections as 2 were superficial and required solely antibiotics. One patient had early failure. Use of a novel fenestrated screw system for the delivery of CaPO4 BSM results in articular subsidence and complication rates similar to previously published values and appears to be a viable option for addressing subchondral defects in tibial plateau fractures. IV.