Medial Condyle Research Articles

Posteromedial knee friction syndrome: Diagnosis by magnetic resonance imaging

Posteromedial knee friction syndrome is a condition rarely discussed in the literature and is characterized as the abnormal movement between the semitendinosus tendon and medial tibial condyle or gracilis and semitendinosus tendons versus semimembranosus tendon or tibial collateral ligament over the tibial crest, causing irritation of the soft tissue around. It occurs especially in active individuals. For the diagnosis, it is recommended to investigate signs and symptoms – pain (mainly in the medial joint line), edema, instability – and relate them to an imaging examination – magnetic resonance imaging (MRI). The literature emphasizes the use of MRI as an imaging method. However, ultrasound undoubtedly has valuable functions, in a way that allows the dynamic study of the posteromedial structures, and also, the treatment guided by ultrasound with corticosteroid and anesthetic. Conservative – physiotherapy and neuromuscular re-education – and surgical – removing the semimembranosus tendon and releasing the semitendinosus and gracilis tendons – treatments are the options for treatment. We present a case of a 46-year-old woman posteromedial friction syndrome diagnosed by an MRI and treated with physiotherapy and local corticosteroid therapy.

Comparison of the femoral condylar ellipse line and the surgical epicondylar axis: 3D measurement by MRI scans in healthy Chinese people.

The sagittal shapes of the femoral condyles were thought to consist of circles. However, the line connecting the centers of circles was not consistent with the surgical epicondylar axis (SEA) which was commonly used in surgery. Recently, ellipses have been proposed as an alternative method to represent the sagittal femoral condylar shape. Does the condylar ellipse line (CEL) coincide with the SEA in 3D MRI reconstruction analysis? From May to August 2021, a total of 80 healthy subjects were scanned by MRI on the right knee in this retrospective study. The ellipses on the most distal slices of the medial and lateral condyles were determined. A line connecting the centers of the medial and lateral ellipses was the CEL. A line connecting the deepest point of the medial sulcus and the most prominent point of the lateral epicondyle was the SEA. Angular measurement of the SEA and the CEL relative to the posterior condylar line (PCL) and the distal condylar line (DCL) was performed on an axial and coronal view of the 3D model, respectively. Measurements were compared between males and females by using the independent-samples t-test. Pearson correlation was used to analyze the relationship between SEA-PCL and CEL-PCL, SEA-DCL, and CEL-DCL. On the axial view, the mean SEA-CEL was 0.35° ± 0.96°. SEA-PCL (2.91° ± 1.40°) had a high correlation with CEL-PCL (3.27° ± 1.11°) (r = 0.731, p < 0.001). On the coronal view, the mean coronal SEA-CEL was 1.35° ± 1.13°. SEA-DCL (1.35° ± 1.13°) had a low correlation with CEL-DCL (0.18° ± 0.84°) (r = 0.319, p = 0.007). On the sagittal view, the outlet points of the CEL on the medial and lateral epicondyles were anatomically located in the anteroinferior direction to the SEA. CEL traversed the medial and lateral epicondyles, which has a mean deviation of 0.35° with SEA on axial view and a mean deviation of 0.18° with DCL on coronal view. This study suggested that the ellipse approach is an improved scheme for representing the femoral condylar shape.

Association of Trochlear Length on Sagittal MRI to Trochlear Dysplasia in Knees With Patellar Instability.

Trochlear dysplasia is a primary risk factor for patellar instability and leads to loss of the osteochondral constraint of the patella. Trochleoplasty techniques include the Peterson grooveplasty, which alters the length of the trochlea; however, a radiographic measurement of trochlear length to support this has not been described. To describe measurements to quantify trochlear length on sagittal magnetic resonance imaging in patients with and without patellar instability and to correlate trochlear length with measurements of trochlear dysplasia. Cross-sectional study; Level of evidence, 3. A total of 66 age- and sex-matched knees (36 female and 30 male; mean age, 20.8 ± 4.8 years) were included in this study, of which 33 had patellar instability. Trochlear extension length (TEL) and trochlear alpha angle (TAA) were measured on 3 sagittal magnetic resonance imaging scans (center of the knee, center of the medial condyle, and center of the lateral condyle), and measurements were compared between symptomatic and control knees. Receiver operating characteristic curve analysis was performed, and the area under the curve (AUC) was calculated to describe the accuracy of each measurement to distinguish between knees with and without patellar instability. Linear and multivariate regression analyses were performed to assess the relationship between sagittal measurements and axial measurements of trochlear dysplasia, including lateral trochlear inclination, sulcus angle, and trochlear depth, as well as patient size reflected by the epicondylar distance. In symptomatic knees, the central trochlea extended more proximally than in control knees, as determined by the TEL (14.0 ± 3.0 vs 11.5 ± 2.3 mm, respectively; P < .001) and TAA (68.4° ± 3.8° vs 70.5° ± 3.4°, respectively; P = .017). AUC calculations showed that a TEL ≥11 mm at the central trochlea was predictive of patellar instability in both male and female knees (AUC = 0.83 and 0.77, respectively), as was a TAA ≤67° in female knees (AUC = 0.72). An independent association between the central TEL and sulcus angle was found. The central TEL showed a weak correlation with patient size, as measured by the epicondylar distance, while the TAA did not. In knees with symptomatic patellar instability, the central trochlea was found to extend 2.5 mm more proximally than in control knees, and this increase in length correlated with severity of trochlear dysplasia. As radiographic examinations of the trochlea and grooveplasty procedures are often based on the proximal extent of the cartilaginous trochlea, further studies are needed to identify the role of trochlear length in the assessment and treatment of trochlear dysplasia in the setting of patellar instability.

Multi-frame biomechanical and relaxometry analysis during in vivo loading of the human knee by spiral dualMRI and compressed sensing.

Knee cartilage experiences repetitive loading during physical activities, which is altered during the pathogenesis of diseases like osteoarthritis. Analyzing the biomechanics during motion provides a clear understanding of the dynamics of cartilage deformation and may establish essential imaging biomarkers of early-stage disease. However, in vivo biomechanical analysis of cartilage during rapid motion is not well established. We used spiral displacement encoding with stimulated echoes (DENSE) MRI on in vivo human tibiofemoral cartilage during cyclic varus loading (0.5 Hz) and used compressed sensing on the k-space data. The applied compressive load was set for each participant at 0.5 times body weight on the medial condyle. Relaxometry methods were measured on the cartilage before (T1ρ , T2 ) and after (T1ρ ) varus load. Displacement and strain maps showed a gradual shift of displacement and strain in time. Compressive strain was observed in the medial condyle cartilage and shear strain was roughly half of the compressive strain. Male participants had more displacement in the loading direction compared to females, and T1ρ values did not change after cyclic varus load. Compressed sensing reduced the scanning time up to 25% to 40% when comparing the displacement maps and substantially lowered the noise levels. These results demonstrated the ease of which spiral DENSE MRI could be applied to clinical studies because of the shortened imaging time, while quantifying realistic cartilage deformations that occur through daily activities and that could serve as biomarkers of early osteoarthritis.

Cadaveric Study to Define the Anatomy of the Medial Patellofemoral Ligament (MPFL) and Its Variant Patterns.

The medial patellofemoral ligament (MPFL) is one of the major soft tissue stabilizers on the medial side of the knee joint, extending from the medial condyle of the femur to the medial aspect of the patella. Different kinds of literature described different sizes and different origins and insertions of MPFL. Injury of MPFL causes patellar instability and dislocation.We reported the anatomy and morphology of MPFL and its implications in the repair of MPFL. The aim of the study was also to look at the variant forms of the MPFL. Methodology: A total of 40 lower limbs fixed in formalin were dissected to study the MPFL of the knee. After reflecting the deep fascia and retinaculum on the medial side of the knee joint the MPFL was exposed. For better learning the lower medial part of vastus medialis was reflected, so that the part of MPFL undercover was exposed. Different forms of MPFL were seen like two straps 12.5%, broad rectangle 20%, and triangular shaped 67.5% MPFL.The origin of MPFL was found between the adductor tubercle and medial epicondyle of the femur and insertion was seen extending from the proximal medial half of the patella to the tendinous aponeurosis of vastus medialis obliquus (VMO) and vastus intermedius muscle (VIM). This is the first study that described three variant patterns of MPFL in accordance with their morphological appearance. This knowledge will be helpful to the surgeons for easy identification and repair of the MPFL.

Clinical significance of distal femur morphology in a healthy Mongolian youth population

Morphological parameters of knee joint are related to race and nationality. At present, knee prosthesis come from white male population. Due to the mismatch between the prosthesis and other ethnic groups, the prosthesis life span is reduced, revision surgery and the patients’ economic burden are increased. There is no data of the Mongolian ethnic group. In order to treat patients more accurately, we measured the Mongolian data of the femoral condyle. A total of 122 knee joints were scanned in 61 volunteers (21 males and 40 females) with an average age of 23.259 ± 1.395 years. The Mimics software was used to reconstruct the 3D image and measure the data of each line. The data were analyzed by statistical methods such as t test, and P < 0.05 was taken as the significant. 122 normal femoral condyle data were obtained. The mean transverse diameter of femoral condyle is 76.472 ± 5.952 mm, medial condyle is 29.259 ± 11.461 mm, and the sagittal diameter of the medial condyle was 56.758 ± 4.163 mm. The transverse diameter of the lateral femoral condyle is 29.388 ± 3.157 mm, the sagittal diameter of the lateral condyle is 58.937 ± 3.527 mm and the femoral plane rate is 1.264 ± 0.072. (1) There was no statistical significance in the left and right knee joint data (P > 0.05). (2) The different genders data of femoral condyle were statistically significant (P < 0.05). (3) Compared with other nationalities and races, the data of femoral condyle are different. (4) There are differences between femoral surface ratio and mainstream prosthesis data.

Morphometrics of Facies Patellaris Femoris in Dry Bones.

The aim of this study was to investigate the morphological features of the distal femur, with a specific focus on the facies patellaris femoris. A total of 45 dry femurs from adult individuals (24 right, 21 left) were used for the study. Measurements were taken using a calibrated digital vernier caliper and a contour gauge. Anteroposterior (AP) measurements were taken for the medial and lateral condyles of the femur, as well as the articular surfaces of the facies patellaris, sulcus height (51.186±3.81mm), trochlear depth (7.436±1.19mm), and trochlear index (2.295±0.06mm). The results showed that the width of the facies patellaris had a significant positive correlation with the trochlear depth and trochlear index. The length of the facies patellaris was positively correlated with the AP length of the medial condyle and sulcus height, although it was not statistically significant. Additionally, there was a statistically significant positive correlation between the length, width, and medial and lateral articular surfaces of the facies patellaris (p<0.005). Understanding the relationship between the morphometry of the medial and lateral condyles of the distal femur and the morphometry of the facies patellaris, sulcus height, trochlear depth, and trochlear indexand examining the anatomy of the distal femur and patella in individualsare crucial factors for determining appropriate medical treatment and implant selection and compatibility. The findings of this study are expected to contribute to clinicians' interventions in this region (total knee arthroplasty/replacement operation etc.). These data can also be used byimplant designersand forensic experts during investigations.

Gross Anatomy of Humerus of Asiatic Lion (Panthera leo persica)

Gir forest is the sole home of Asiatic lion. In the present study the anatomy of 4 humerus bones of Asiatic lion were studied. The humerus is long bone with spirally twisted shaft. The mean circumference of proximal extremity was 21.11 cm, while that of distal extremity was 18.00 cm. The mean length of shaft was 17.20 cm. The mean diameter of shaft from the middle was 8.62 cm. The musculo-spiral groove was wide, smooth and spiral on lateral surface of humerus. There were three fossae, olecranon fossa at caudal aspect and radial and coronoid fossae at cranial aspect of distal extremity of humerus. Supracondyloid foramen was present on medial side of distal extremity above medial condyle.

Combined Free Flaps for Optimal Orthoplastic Lower Limb Reconstruction: A Retrospective Series.

Background and Objectives: Open fracture of the lower limb can lead to substantial bone and soft tissue damage, resulting in a challenging reconstructive scenarios, especially in presence of bone or periosteal loss, with a relevant risk of non-union. This work analyzes outcomes of using a double approach for orthoplastic reconstruction, adopting the free medial condyle flap to solve the bone defects, associated to a second free flap for specific soft tissue coverage. Indications, outcomes and reconstructive rationales are discussed. Materials and Methods: A retrospective investigation was performed on patients who underwent complex two-flap microsurgical reconstruction from January 2018 to January 2022. Inclusion criteria in this study were the use of a free femoral condyle periostal/bone flap together with a second skin-only flap. Only distal third lower limb reconstructions were included in order to help equalize our findings. Out of the total number of patients, only patients with complete pre- and post-operative follow-up (minimum 6 months) data were included in the study. Results: Seven patients were included in the study, with a total of 14 free flaps. The average age was 49. Among comorbidities, four patients were smokers and none suffered from diabetes. Etiology of the defect was acute trauma in four cases and septic non-union in three cases. No major complications occurred, and all flaps healed uneventfully with complete bone union. Conclusions: Combining a bone periosteal FMC to a second skin free flap for tailored defect coverage allowed achievement of bone union in all patients, despite the lack of initial bone vascularization or chronic infection. FMC is confirmed to be a versatile flap for small-to-medium bone defects, especially considering its use as a periosteal-only flap, with minimal donor site morbidity. Choosing a second flap for coverage allows for a higher inset freedom and tailored reconstruction, finally enhancing orthoplastic success.

OVINE KNEE KINEMATICS AND CONTACT PRESSURES OF A NOVEL FIBRE MATRIX-REINFORCED HYDROGEL TOTAL MENISCUS REPLACEMENT

No proven long-term joint-preserving treatment options exist for patients with irreparable meniscal damage. This study aimed to assess gait kinematics and contact pressures of novel fibre-matrix reinforced polyvinyl alcohol-polyethylene glycol (PVA-PEG) hydrogel meniscus implanted ovine stifle joints against intact stifles in a gait simulator.The gait simulator controlled femoral flexion-extension and applied a 980N axial contact force to the distal end of the tibia, whose movement was guided by the joint natural ligaments (Bartolo; ORS 2021;p1657- LB). Five right stifle joints from sheep aged &gt;2 years were implanted with a PVA-PEG total medial meniscus replacement, fixed to the tibia via transosseous tunnels and interference screws. Implanted stifle joint contact pressures and kinematics in the simulator were recorded and compared to the intact group. Contact pressures on the medial and lateral condyles were measured at 55° flexion using Fujifilm Prescale Low Pressure film inserted under the menisci. 3D kinematics were measured across two 30 second captures using the Optotrak Certus motion-tracking system (Northern Digital Inc.).Medial peak pressures were not significantly different between the implanted and intact groups (p&gt;0.4), while lateral peak pressures were significantly higher in the implanted group (p&lt;0.01). Implanted stifle joint kinematics in the simulator did not differ significantly from the intact baseline (p&gt;0.01), except for in distraction-compression (p&lt;0.01).Our findings show that the fibre-matrix reinforced PVA-PEG hydrogel meniscal replacement restored the medial peak contact pressures. Similar to published literature (Fischenich; ABE 2018;46(11):1–12), the lateral peak pressures in the implanted group were higher than the intact. Joint kinematics were similar across groups, with slightly increased internal-external rotation in the implanted group. These findings highlight the effectiveness of the proposed approach and motivate future work on the development of a total meniscal replacement.

Clinical outcomes in patients with scaphoid non-union treated with the vascularized medial femoral condyle technique a case series

IntroductionNon-union is a prevalent complication of scaphoid fractures. Late diagnosis is common and has a clinical impact due to functional limitations for the patient. Multiple treatments have been proposed to manage this complication, ranging from conservative (i.e., orthopedic) to surgical treatment. The vascularized medial femoral condyle technique has shown satisfactory clinical and paraclinical results, mainly in presence of avascular necrosis of the proximal pole but data regarding functional outcomes and patient satisfaction is scarce.This case series aims to describe the clinical and patient-reported outcomes in a consecutive series of patients with non-union of the proximal third of the scaphoid treated with vascularized medial femoral condyle technique. MethodsCase series reporting results for a consecutive – initial cohort of patients who presented with a non united fracture of the proximal pole of the scaphoid, avascular necrosis of the proximal pole was documented by CT od MRI imaging preoperatively in all patients. Measurement instruments include the q-DASH and PRWE questionnaires, radiographic images, goniometry, and assessment of grip strength. ResultsTwelve consecutive patients are included and they represent the initial cases for all surgeons involved; bone union was obtained in 10 patients (83%) after a mean follow-up time of 31 months (6–72), successful improvement in the range of motion and grip strength was documented. A high rate of satisfaction expressed by the patient was obtained, with an average score in Q-DASH of 17.3 and 20.1 in PRWE. ConclusionsThe vascularized medial condyle technique in cases of nonunion of scaphoid fracture is a reproducible treatment in clinical terms, both in imaging and functional terms, and in patient satisfaction. The learning curve is flat for a dedicated multi surgeon team.

HOW DOES TIBIOFEMORAL CONTACT PRESSURE DEFINE STRESS CONTACT LIMITS IN THE PRESENCE OF FULL-THICKNESS CHONDRAL DEFECT SIZE ON THE MEDIAL AND LATERAL CONDYLE AT FULL EXTENSION?

Chondral defects in the knee have cartilage biomechanical differences due to defect size and orientation. This study examines how the tibiofemoral contact pressure is affected by increasing full-thickness chondral defect size on the medial and lateral condyle at full extension.Isolated full-thickness, square chondral defects increasing from 0.09cm2 to 1.0cm2 were created sequentially on the medial and lateral femoral condyles of six human cadaveric knees with intact ligaments and menisci. Chondral defects were created 1.0cm from the femoral notch posteriorly. The knees were fixed to a uniaxial load frame and loaded from 0N to 600N at full extension. Contact pressures between the femoral and tibial condyles were measured using pressure mapping sensors. The peak contact pressure was defined as the highest value in the 2.54mm2 area around the defect. The location of the peak contact pressure was determined relative to the centre of the defect.Peak contact pressure was significantly different between (4.30MPa) 0.09cm2 and (6.91MPa) 1.0cm2 defects (p=0.04) on the medial condyle. On the lateral condyle, post-hoc analysis showed differences in contact pressures between (3.63MPa) 0.09cm2 and (5.81MPa) 1.0cm2 defect sizes (p=0.02).The location of the stress point shifted from being posteromedial (67% of knees) to anterolateral (83%) after reaching a 0.49cm2 defect size (p &lt; 0.01) in the medial condyle. Conversely, the location of the peak contact pressure point moved from being anterolateral (50%) to a posterolateral (67%) location in defect sizes greater than 0.49cm2 (p &lt; 0.01).Changes in contact area redistribution and cartilage stress from 0.49cm2 to 1.0cm2 impact adjacent cartilage integrity. The location of the maximum stress point also varied with larger defects. This study suggests that size cutoffs exist earlier in the natural history of chondral defects, as small as 0.49cm2, than previously studied, suggesting a lower threshold for intervention.

CARTILAGE AND SUBCHONDRAL BONE CHANGES IN OSTEOARTHRITIS CAN BE DETECTED QUANTITATIVELY USING IN VIVO IMAGING

Cartilage diseases have a significant impact on the patient's quality of life and are a heavy burden for the healthcare system. Better understanding, early detection and proper follow-up could improve quality of life and reduce healthcare related costs. Therefore, the aim of this study was to evaluate if difference between osteoarthritic (OA) and non-osteoarthritic (non-OA) knees can be detected quantitatively on cartilage and subchondral bone levels with advanced but clinical available imaging techniques.Two OA (mean age = 88.3 years) and three non-OA (mean age = 51.0 years) human cadaveric knees were scanned two times. A high-resolution peripheral quantitative computed tomography (HR-pQCT) scan (XtremeCT, Scanco Medical AG, Switzerland) was performed to quantify the bone microstructure. A contrast-enhanced clinical CT scan (GE Revolution Evo, GE Medical Systems AG, Switzerland) was acquired with the contrast agent Visipaque 320 (60 ml) to measure cartilage. Subregions dividing the condyle in four parts were identified semi-automatically and the images were segmented using adaptive thresholding. Microstructural parameters of subchondral bone and cartilage thickness were quantified.The overall cartilage thickness was reduced by 0.27 mm between the OA and non-OA knees and the subchondral bone quality decreased accordingly (reduction of 33.52 % in BV/TV in the layer from 3 to 8 mm below the cartilage) for the femoral medial condyle. The largest differences were observed at the medial part of the femoral medial condyle both for cartilage and for bone parameters, corresponding to clinical observations.Subchondral bone microstructural parameters and cartilage thickness were quantified using in vivo available imaging and apparent differences between the OA and non-OA knees were detected. Those results may improve OA follow-up and diagnosis and could lead to a better understanding of OA. However, further in vivo studies are needed to validate these methods in clinical practice.

Characterizing site-specific mechanical properties of knee cartilage with indentation-relaxation maps and machine learning

Knee cartilage experiences site-specific focal lesion and degeneration, which is likely associated with tissue inhomogeneity and nonuniform mechanical stimuli in the joint, for which a complete picture remains to be depicted. The present study aimed to develop a methodology to quantify knee cartilage inhomogeneity using porcine knee specimens. Automated indentation-relaxation and needle probing were performed on fully intact cartilage to obtain data that essentially represent continuous distributions of cartilage properties in the knee. Machine learning was then introduced to approximate the tissue inhomogeneity with several regions via clusters of indentation locations, and finite element modeling was used to obtain poromechanical properties for each region using indentation-relaxation and thickness data. Significant region dependence was established from the full time-dependent mechanical response. Seventeen regions, or clusters, were found to best approximate the site-specific poromechanical properties of articular cartilage for femoral groove, lateral and medial condyles and tibial plateaus, after up to eight clusters were tested for each of the five cartilage sections. The region partitions recommended, and tissue properties acquired would facilitate implementation of tissue inhomogeneity in future applications, e.g., contact modeling of the knee joint. The results obtained from 14 porcine knees revealed interesting region differences, for example, the two condyles have the same effective stiffness when responding to slowly applied mechanical loadings but substantially lower stiffness in the medial condyle when responding to fast loadings. This mechanical behavior may be associated with the fact that medial femoral cartilage is more prone to focal lesions than the lateral one.

Gait Variability Structure Linked to Worse Cartilage Composition Post-ACL Reconstruction.

Aberrant gait variability has been observed after anterior cruciate ligament reconstruction (ACLR), yet it remains unknown if gait variability is associated with early changes in cartilage composition linked to osteoarthritis development. Our purpose was to determine the association between femoral articular cartilage T1ρ magnetic resonance imaging relaxation times and gait variability. T1ρ magnetic resonance imaging and gait kinematics were collected in 22 ACLR participants (13 women; 21 ± 4 yr old; 7.52 ± 1.43 months post-ACLR). Femoral articular cartilage from the ACLR and uninjured limbs were segmented into anterior, central, and posterior regions from the weight-bearing portions of the medial and lateral condyles. Mean T1ρ relaxation times were extracted from each region and interlimb ratios (ILR) were calculated (i.e., ACLR/uninjured limb). Greater T1ρ ILR values were interpreted as less proteoglycan density (worse cartilage composition) in the injured limb compared with the uninjured limb. Knee kinematics were collected at a self-selected comfortable walking speed on a treadmill with an eight-camera three-dimensional motion capture system. Frontal and sagittal plane kinematics were extracted, and sample entropy was used to calculate kinematic variability structure (KV structure ). Pearson's product-moment correlations were conducted to determine the associations between T1ρ and KV structure variables. Lesser frontal plane KV structure was associated with greater mean T1ρ ILR in the anterior lateral ( r = - 0.44, P = 0.04) and anterior medial condyles ( r = - 0.47, P = 0 .03). Lesser sagittal plane KV structure was associated with greater mean T1ρ ILR in the anterior lateral condyle ( r = - 0.47, P = 0.03). The association between less KV structure and worse femoral articular cartilage proteoglycan density suggests a link between less variable knee kinematics and deleterious changes joint tissue changes. The findings suggest that less knee kinematic variability structure is a mechanism linking aberrant gait to early osteoarthritis development.

Aid in need - Manageable but not ideal a tale of knee replacement in distal femur fracture for early mobilisation

We present a case of 70 year female who is a prior patient for knee arthritis at our clinic and who fell down and sustained a fracture in left distal femur over medial condyle. Patient demand was early mobilization. We discussed various options of management and advantages, disadvantages and complications. As per patient request planned for bilateral knee replacement with fracture stabilization. Postop recovery is monitored and patient recovered and is able to walk and satisfactory range of movement of both knee was achieved this case adds to the evidence that elderly distal femur fractures that can be replacement and made to walk as early as possible. Especially in scenarios of arthritis and fracture together.: Informed consent was obtained from the patient and family for the publication of the case report and all the figures included.

Estimation of the Cartilage Volume Loss Due to Knee Osteoarthritis - Case Study

Osteoarthritis (OA) is a degenerative disease of the knee joint caused by the formation of cracks within the collagen fibers of the articular cartilage. Current research is directed towards less invasive procedures for treating this degenerative disease using tissue engineering and 3D bioprinting. Therefore, it is crucial to obtain the exact shape of the damaged tissue, reconstruct the original shape of the tissue, and estimate the volume and area resulting from the wear of the contact surfaces. The study used the tibial plateau of a patient with OA that was removed during total knee arthroplasty, and the data was collected using a 3D scanner. After the reconstruction of the tibial plateau, an assessment of the area and volume of wear on the medial condyle of the tibia was performed, along with a FEM analysis of the real and approximate shape of the cartilage tissue. In this way, it is possible to simulate and create a patient-specific 3D model with a reconstructed wear volume, which can be highly attractive for future treatment strategies for cartilage damage or early stages of OA.

"Grand-piano sign" as a femoral rotational indicator in both varus and valgus knees: a simulation study of anterior resection surface in total knee arthroplasty.

The "Grand-piano sign" is a popular indicator of the appropriate rotational alignment of the femoral component during total knee arthroplasty (TKA). The aim of the study was to investigate the shape of the anterior femoral resection surface of varus and valgus knees. A cohort of 80 varus knees and 40 valgus knees (hip-knee-ankle angle > 2° for varus and < -2° for valgus knees) matched for age, sex, height, body weight, and KL grade was made using propensity score matching. Virtual TKA was performed using 3 patterns of components (anterior flange flexion angles of 3°, 5°, and 7°). The anterior femoral resection surface was evaluated for 3 patterns of rotational alignments: parallel to the surgical epicondylar axis (NR, neutral rotation), 3° internal rotation (IR), and 3°external rotation (ER) relative to the surgical epicondylar axis. In each anterior femoral resection surface, the vertical height of medial and lateral condyles was measured, and the ratio of the medial to the lateral height (M/L ratio) was evaluated. The M/L ratio in NR for both varus and valgus knees was 0.57 to 0.64, with no significant difference between the cohorts (p value > 0.05). The M/L ratio showed a similar pattern of increasing at IR and decreasing at ER in both varus and valgus knees. The variation in the M/L ratio with malrotation in valgus knees was smaller than in varus knees. During TKA, the anterior femoral resection surface was similar in varus and valgus knees; however, the variation with malrotation was smaller in valgus knees than in varus knees. TKA for valgus knees requires precise surgical technique and careful intraoperative assessment. IV, Case series.

Femoral condyle bone mineral density in osteoarthritis differs significantly between knees with valgus vs. varus deformity

BackgroundThe objective of this study was to measure bone mineral density (BMD) of the cancellous bone in both femoral condyles and to compare the results according to the hip-knee-ankle (HKA) angle in patients with knee osteoarthritis. HypothesisBMD of cancellous bone in the medial condyle is markedly lower in valgus knees compared to that in the lateral condyle in varus knees. MethodsConsecutive patients with computed tomography (CT) of the knee and long-leg radiographs obtained in preparation for total knee arthroplasty were included. The 189 knees were divided into five groups based on whether the hip-knee-ankle angle was<170° (major varus deformity), 171°–177° (varus deformity), 178°–182° (normal alignment), 183°–189° (valgus deformity), and>190° (major valgus deformity). A protocol for CT measurement of BMD values at the femoral condyles was developed. Correlations between the HKA angle and BMD were assessed using the ratio of medial-to-lateral condyle BMD values (M/L). ResultsM/L was lower for knees with valgus deformity than for normally aligned knees (0.7 vs. 1, p<0.001). This difference was larger in the group with major valgus deformity, with a mean M/L value of 0.5 (p<0.001). M/L was higher for knees with major varus (mean, 1.2; p=0.035). The correlation coefficients showed excellent intra-observer and inter-observer agreement for the BMD measurements. ConclusionThe BMD values of the femoral condyles correlate with the HKA angle. BMD is lower at the medial femoral condyle of valgus knees, particularly when the deformity exceeds 10°. This finding may deserve consideration when planning total knee arthroplasty. Level of evidenceIV; retrospective study.

Trajectory of bearing movement during Oxford mobile-bearing unicompartmental knee arthroplasty using a kinematic alignment technique.

Trajectory of bearing movement during Oxford mobile-bearing unicompartmental knee arthroplasty using a kinematic alignment technique.