Sex-dependent variation in cartilage adaptation: from degeneration to regeneration.

Despite acknowledgement in the scientific community of sex-based differences in cartilage biology, the implications for study design remain unclear, with many studies continuing to arbitrarily assign demographics. Clinically, it has been well-established that males and females differ in cartilage degeneration, and accumulating evidence points to the importance of sex differences in the field of cartilage repair. However, a comprehensive review of the mechanisms behind this trend and the influence of sex on cartilage regeneration has not yet been presented. This paper aims to summarize current findings regarding sex-dependent variation in knee anatomy, sex hormones' effect on cartilage, and cartilaginous degeneration and regeneration, with a focus on stem cell therapies. Findings suggest that the stem cells themselves, as well as their surrounding microenvironment, contribute to sex-based differences. Accordingly, this paper underscores the contribution of both stem cell donor and recipient sex to sex-related differences in treatment efficacy. Cartilage regeneration is a field that needs more research to optimize strategies for better clinical results; taking sex into account could be a big factor in developing more effective and personalized treatments. The compilation of this information emphasizes the importance of investing further research in sex differences in cartilage biology.

Anatomy of the Medial Meniscotibial Ligament of the Knee: A Systematic Review / Anatomia do ligamento meniscotibial medial do joelho: Uma revisão sistemática

Abstract Objectives To perform a systematic review of the literature on the anatomy of the medial meniscotibial ligaments (MTLs), and to present the most accepted findings, as well as the evolution of the anatomical knowledge on this structure. Materials and Methods An electronic search was conducted in the MEDLINE/PubMed, Google Scholar, EMBASE and Cochrane library databases with no date restrictions. The following index terms were used in the search: anatomy AND meniscotibial AND ligament AND medial. The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We included anatomical studies of the knee were included, such as cadaver dissections, histological and/or biological investigations, and/or imaging of the medial MTL anatomy. Results Eight articles that met the inclusion criteria were selected. The first article was published in 1984 and the last, in 2020. The total sample in the 8 articles was of 96 patients. Most studies are purely descriptive in terms of the macroscopic morphological and microscopic histological findings. Two studies evaluated the biomechanical aspects of the MTL, and one, the anatomical correlation with the magnetic resonance imaging examination. Conclusion The main function of the medial MTL, a ligament that originates in the tibia and is inserted in the lower meniscus, is to stabilize and maintain the meniscus in its position on the tibial plateau. However, there is a limited amount of information regarding medial MTLs, primarily in terms of anatomy, especially vascularization and innervation.

Resumo Objetivos Fazer uma revisão sistemática da literatura sobre a anatomia dos ligamentos meniscotibiais (LMTs) mediais, e apresentar os achados mais aceitos e a evolução das informações anatômicas sobre essa estrutura. Materiais e Métodos A busca eletrônica foi realizada nos bancos de dados MEDLINE/PubMed, Google Scholar, EMBASE e Cochrane, sem restrições de data. Os seguintes termos de indexação foram utilizados: anatomy AND meniscotibial AND ligament AND medial. A revisão seguiu as recomendações da declaração de Principais Itens para Relatar Revisões Sistemáticas e Metanálises (Preferred Reporting Items for Systematic Reviews and Meta-Analyses, PRISMA, em inglês). Foram incluídos estudos anatômicos do joelho, como dissecções de cadáveres, investigações histológicas e/ou biológicas, e/ou imagens da anatomia do LMT medial. Resultados Oito artigos atenderam aos critérios de inclusão e foram selecionados. O primeiro foi publicado em 1984, e o último, em 2020. A amostra total nos 8 artigos foi de 96 pacientes. A maioria dos estudos é puramente descritiva em relação aos achados morfológicos macroscópicos e histológicos microscópicos. Dois estudos avaliaram os aspectos biomecânicos do LMT, e um analisou a correlação anatômica com o exame de ressonância magnética. Conclusão A principal função do LMT medial, ligamento que se origina na tíbia e se insere no menisco inferior, é estabilizar e manter a posição do menisco no platô tibial.

Automatic segmentation of human knee anatomy by a convolutional neural network applying a 3D MRI protocol.

BACKGROUND: To study deep learning segmentation of knee anatomy with 13 anatomical classes by using a magnetic resonance (MR) protocol of four three-dimensional (3D) pulse sequences, and evaluate possible clinical usefulness. METHODS: The sample selection involved 40 healthy right knee volumes from adult participants. Further, a recently injured single left knee with previous known ACL reconstruction was included as a test subject. The MR protocol consisted of the following 3D pulse sequences: T1 TSE, PD TSE, PD FS TSE, and Angio GE. The DenseVNet neural network was considered for these experiments. Five input combinations of sequences (i) T1, (ii) T1 and FS, (iii) PD and FS, (iv) T1, PD, and FS and (v) T1, PD, FS and Angio were trained using the deep learning algorithm. The Dice similarity coefficient (DSC), Jaccard index and Hausdorff were used to compare the performance of the networks. RESULTS: Combining all sequences collectively performed significantly better than other alternatives. The following DSCs (±standard deviation) were obtained for the test dataset: Bone medulla 0.997 (±0.002), PCL 0.973 (±0.015), ACL 0.964 (±0.022), muscle 0.998 (±0.001), cartilage 0.966 (±0.018), bone cortex 0.980 (±0.010), arteries 0.943 (±0.038), collateral ligaments 0.919 (± 0.069), tendons 0.982 (±0.005), meniscus 0.955 (±0.032), adipose tissue 0.998 (±0.001), veins 0.980 (±0.010) and nerves 0.921 (±0.071). The deep learning network correctly identified the anterior cruciate ligament (ACL) tear of the left knee, thus indicating a future aid to orthopaedics. CONCLUSIONS: The convolutional neural network proves highly capable of correctly labeling all anatomical structures of the knee joint when applied to 3D MR sequences. We have demonstrated that this deep learning model is capable of automatized segmentation that may give 3D models and discover pathology. Both useful for a preoperative evaluation.

Anatomical Study of the Medial Region of the Knee: Qualitative, Quantitative Analysis and Description of the Anterior Oblique Ligament / Estudo anatômico da região medial do joelho: Análise qualitativa, quantitativa e descrição do ligamento oblíquo anterior

Abstract Objective To describe all ligamentous, capsular, tendinous and bone landmarks structures of the medial region of the knee, as well as a new ligamentous structure identified in a series of anatomical dissections of cadaveric specimens. Methods Twenty cadaver knees were dissected to study the medial compartment. The main structures of this region were identified during dissection. The morphology of the structures and their relationship with known anatomical parameters were determined both qualitatively and quantitatively. The collected data were analyzed and interpreted using descriptive statistics. Results In the dissection of all specimens, all ligamentous structures previously described in the anatomical study of the medial part of the knee were identified, and objective measures that can help as parameters for surgical ligament reconstruction were identified. When dissecting the medial collateral ligament, a bony prominence immediately distal to its proximal tibial insertion was observed and described, as well as a bursa below the ligament, in which it was not inserted. We also described a ligamentous structure with extracapsular location, originated anteriorly to the medial epicondyle and following obliquely towards the tibia. These structures were named, respectively, interinsertional tubercle, interinsertional bursa and anterior oblique ligament. Conclusion In addition to the description and measurement of the structures and parameters already existing in the anatomical study of the medial part of the knee, it was possible to describe three new structures not yet described in the literature: the interinsertional tubercle, the interinsertional bursa, and the anterior oblique ligament. These structures were found in all dissections performed.

Resumo Objetivo Descrever todas as estruturas ligamentares, capsulares, tendinosas e marcos ósseos da região medial do joelho, assim como uma nova estrutura ligamentar identificada em uma série de dissecções anatômicas de espécimes cadavéricos. Métodos Vinte joelhos de cadáveres foram dissecados para estudar o compartimento medial. As principais estruturas dessa região foram identificadas durante a dissecção. A morfologia das estruturas e sua relação com parâmetros anatômicos conhecidos foram determinados tanto de forma qualitativa quanto de forma quantitativa. Os dados coletados foram analisados e interpretados por meio de estatística descritiva. Resultados Na dissecção de todos os espécimes, foram identificadas todas as estruturas ligamentares já descritas anteriormente no estudo anatômico da porção medial do joelho, e foram realizadas medidas objetivas que podem auxiliar como parâmetros para a reconstrução ligamentar cirúrgica. Foram observados e descritos, ainda, ao se desprender o ligamento colateral medial superficial, uma proeminência óssea imediatamente distal à sua inserção tibial proximal, uma bursa abaixo do ligamento, na qual o mesmo não se mostrava inserido, assim como uma estrutura ligamentar localizada extracapsularmente e com origem na face anterior do epicôndilo medial, seguindo obliquamente em direção à tíbia, aos quais foram dados os nomes, respectivamente, de tubérculo interinsercional, bursa interinsercional e ligamento oblíquo anterior. Conclusão Além da descrição e medida das estruturas e parâmetros já existentes no estudo anatômico da porção medial do joelho, foi possível a descrição de três novas estruturas: o tubérculo interinsercional a bursa interinsercional e o ligamento oblíquo anterior, ainda não descritos na literatura. Essas estruturas foram encontradas em todas as dissecções realizadas.

Assessing the racial differences in Q angle measurements in relevance to articular cartilage of the femoral condyle: a retrospective ultrasound study / Evaluación de las diferencias raciales en las mediciones del ángulo Q en relación con el cartílago articular del cóndilo femoral: un estudio ecográfico retrospectivo

SUMMARY: The Q-angle is defined as the acute angle formed by the vectors for combined pull of the quadriceps femoris muscle and the patellar tendon. This study aimed to investigate the variations in Q angle with respect to race. Moreover, this study performed ultrasound to evaluate of the thickness of articular cartilage covering the medial and lateral femoral condyle in volunteers with an increased Q angle. The study included 487 Jordanian and 402 Malaysians with age range 18-23 years. Moreover, the study included 30 participants aged between 18 and 22 years, with a total of 15 volunteers with Q >14° and 15 patients with Q ≤14°. Both Q angle and condylar distance were measured by well-trained medical practitioners according to a well-established protocol. The thickness of articular cartilage covering the medial and lateral femoral condyle of the femoral bone was measured using ultrasound. Regardless of race, Q angle was greater in females. Furthermore, Q angle was significantly greater in Arab volunteers compared to Malay volunteers. Q angle significantly increase with increasing condylar distance in both races. Finally, the statistical analysis showed a significantly reduced thickness of articular cartilage on both medial and lateral femoral condyle (P = 0.05) in the Q >14° group. Multiple factors including race and condylar distance and even the articular cartilage of femoral condyle should be considered during the examination and management of knee fractures and condylar diseases.

RESUMEN: El ángulo Q se define como el ángulo agudo formado por los vectores de tracción combinada del músculo cuádriceps femoral y el tendón patelar. Este estudio tuvo como objetivo investigar las variaciones en el ángulo Q con respecto a la raza. Además, se realizó una ecografía para evaluar el grosor del cartílago articular que cubre los cóndilos femorales medial y lateral en voluntarios con un ángulo Q aumentado. El estudio incluyó a 487 jordanos y 402 malayos con un rango de edad de 18 a 23 años. Además, el estudio incluyó a 30 participantes con edades comprendidas entre 18 y 22 años, 15 voluntarios con Q> 14 ° y 15 pacientes con Q ≤ 14 °. Tanto el ángulo Q como la distancia condilar fueron medidos por médicos bien entrenados de acuerdo con un protocolo establecido. El grosor del cartílago articular que cubre los cóndilos femorales medial y lateral del fémur se midió mediante ecografía. Independientemente del grupo racial, el ángulo Q fue mayor en las mujeres. Además, el ángulo Q fue significativamente mayor en los voluntarios árabes en comparación con los voluntarios malayos. El ángulo Q se aumenta significativamente al incrementarse la distancia condilar en ambas grupos raciales. Finalmente, el análisis estadístico mostró una reducción significativa del grosor del cartílago articular en los cóndilos femorales medial y lateral (P = 0,05) en el grupo Q> 14. Durante la exploración y el tratamiento de las fracturas de rodilla y de las enfermedades condilares, se deben considerar múltiples factores, incluida la raza y la distancia condilar e incluso el cartílago articular del cóndilo femoral.

Anthropometric study as a predictor of anterior cruciate ligament sizes in Asian Indonesian population.

OBJECTIVES: To evaluate whether anthropometric data can predict anterior cruciate ligament (ACL) sizes on magneti resonance imaging (MRI) in Asian population. BACKGROUND: Reconstruction of ACL has been performed over a decade ago. Recently, more individualized ACL reconstruction is performed taking account of each patient's ACL characteristics. However, there has been limited study regarding ACL sizes in Asian Indonesian population. This study aimed to evaluate the role of anthropometric data in ACL sizes using MRI in Asian Indonesian population. STUDY DESIGN: Retrospective Study. METHOD: A series of 531 knees from 420 patients with knee pain and intact ACL confirmed by MRI study. Length, width and inclination angle of ACL were measured using a T2-weighted sagittal MRI 3.0 Tesla Magnetom Skyra. Height, weight, body mass index (BMI) and age were recorded. Multiple regression analysis was used to determine relationship between the anthropometric data and size of ACL measurements. RESULT: ACL length and width were significantly different between male and female, consecutively. Mean ACL length was 35.36 ± 3.63 mm, male was significantly longer (36.59 ± 3.24 mm) compared to female (32.77 ± 2.99 mm), p < 0.0001. Mean ACL width was 10.23 ± 1.84 mm, male was significantly wider (10.85 ± 1.59 mm) compared to female (8.93 ± 1.64 mm), p < 0.0001. The mean ACL inclination angle was 47.75° ± 3.07° (range 40.17°-57.12°). The strongest correlation for ACL length was height and weight (r = 0.437; r = 0.341 consecutively, p < 0.0001). Females had stronger correlation compared to males for ACL length (R2 = 0.489 vs R2 = 0.418). ACL width showed weak correlation with anthropometric data. The following regression analysis equation was obtained for ACL length: ACL length = 60.697 - 0.11*age + 0.461*weight (kg) - 16.522*height (meter) - 1.093*BMI (R2 = 0.539; p < 0.0001). CONCLUSION: Anthropometric data can be utilized as a predictor of ACL length in Asian Indonesian population. The ACL length in Asian Indonesian population is shorter than that in Western population study.

How the orientation of osteotomy in biplanar lateral closed-wedge distal femoral osteotomy influences the rotational alignment of the knee in all dimensional planes.

BACKGROUND: Correction of coronal plane deformity by osteotomies around the knee is theoretically three-dimensional (3D) and can be associated with changes in other planes. It has been shown that 3D rotational changes are induced by biplanar high tibial osteotomy; however, relevant information in biplanar lateral closed-wedge distal femoral osteotomy (LCW-DFO) has not been reported in literatures. This study aimed to investigate rotational changes in axial and sagittal planes in LCW-DFO using computer-aided design (CAD) simulations. METHODS: LCW-DFO is composed of three cuts: one ascending cut and two transverse cuts. In the simulations, the following geometrical parameters were adopted as factors potentially influencing 3D changes occurring in the osteotomy. The ascending cut angle measured as the angle between the edge of the ascending cut and the edge of the transverse cut in the lateral view, and the ascending cut obliquity measured as the angle corresponding to anterior/posterior inclination of the ascending cut with reference to the posterior condylar tangent line in the axial view. In the analysis, the effects of these bony cut angles on associated rotational changes in the axial and sagittal planes (internal/external rotation and flexion/extension) were calculated. Variation of wedge size ranged from 2 to 8 mm. RESULTS: The degree of the ascending cut obliquity substantially correlated with associated change in the sagittal plane (extension/flexion) while inducing only minimal change in rotation in the axial plane (internal/external rotation). When the osteotomy was made without ascending cut obliquity, the change in knee extension/flexion was minimal for the conditions analyzed while coupled internal rotation of the distal bony segment was induced. CONCLUSIONS: In biplanar LCW-DFO, the ascending cut angle substantially influenced the amount of internal rotation of the distal bony segment with little effect on flexion/extension angles. By contrast, ascending cut obliquity in the axial plane yields an effect on flexion/extension angles and little effect on internal rotation of the distal bony segment.

Unique morphology of intraoperative measurement of distal femur in northern malaysian females and its correlation with total knee arthroplasty implant sizing / Morfología única de la medición intraoperatoria del fémur distal en mujeres del norte de malasia y su correlación con el tamaño del implante en artroplastia total de rodilla

SUMMARY: Accurate implant sizing is one of the major determinants in defining the success of total knee arthroplasty (TKA). Current TKA implants are based on Caucasian knee morphometry which is well documented to be larger than Asian knees. Even more, with regards to sizing, implant mismatch tends to be more evident in the female population. This study was designed to evaluate the distal femur dimensions of Malaysian female patients who underwent TKA in our institution and to compare them with the current prosthetic system in use. A total of 199 female patients (207 knees) who underwent TKA were enrolled in this study. Intraoperatively, the AP dimensions (medial and lateral condyles) and mediolateral (ML) width were measured. Known dimension of the femoral component of the prosthetic knee system currently in use were compared with the morphological data. The average femoral component overhang was 2.11 mm (SD 3.94 mm). There was significant difference between the mean ML width of the resected femur and the femoral component (p<0.01). Analysis also revealed a significant positive and weak relationship between both, AP (medial and lateral) and ML dimension. The aspect ratio (ML/AP) of the native femur was generally smaller than the implant aspect ratio which is likely to cause overhang in our population. In general, this study shows that the knees of our female sub-population are even narrower than the other Asian female knees from previous studies. Implants should be designed based on the morphological data of the local population. Implant manufactures should tailor them to accommodate a smaller change in ML width for an increment in the AP length and provide several ML widths for one AP length to obtain a better fitting prosthesis hence curbing the problem of ML overhang.

RESUMEN: El tamaño exacto del implante es uno de los principales determinantes para definir el éxito de la artroplastía total de rodilla (ATR). Los implantes de TKA se basan en la morfometría de rodilla caucásica, cuyo tamaño está reportado como mayor que las rodillas asiáticas. Más aún, en lo que respecta al tamaño, el desajuste de los implantes tiende a ser más evidente en la población femenina. Este estudio fue diseñado para evaluar las dimensiones del fémur distal de pacientes mujeres malasias que se sometieron a ATR en nuestra institución y compararlas con el sistema protésico actual. En este estudio se incluyeron un total de 199 pacientes (207 rodillas) que se sometieron a ATR. Intraoperatoriamente, se midieron las dimensiones AP (cóndilos medial y lateral) y el ancho mediolateral (ML). Se comparó la dimensión conocida del componente femoral del sistema protésico de rodilla actualmente en uso con los datos morfológicos. El voladizo o sobresaliencia del componente femoral fue de 2,11 mm (DE 3,94 mm). Hubo una diferencia significativa entre el ancho ML medio del fémur resecado y el componente femoral (p <0,01). El análisis también reveló una relación significativa positiva y débil entre las dimensiones AP (medial y lateral) y ML. La relación de aspecto (ML / AP) del fémur nativo fue más pequeña que la relación de aspecto del implante, lo que probablemente cause un voladizo en nuestra población. En general, este estudio muestra que las rodillas de nuestra subpoblación femenina son incluso más estrechas que otras rodillas de mujeres asiáticas reportadas en estudios anteriores. Los implantes deben ser diseñados en base a los datos morfológicos de la población local. Los fabricantes de implantes deben adaptarlos a un cambio más pequeño en el ancho de ML para un incremento en la longitud AP y proporcionar varios anchos ML para una longitud AP con el objetivo de obtener una prótesis de mejor ajuste y frenar el problema del voladizo ML.

The anatomy of Kaplan fibers.

PURPOSE: Kaplan fibers (KF) have been described as connections between the iliotibial band and the distal femur. They are divided into two distinct structures, proximal (PKF) and distal (DKF) fibers, which may participate in the control of the rotatory knee stability. Their anatomical characteristics have not been investigated completely, in particular with respect to reconstruction procedures. The aim was to determine their anatomical characteristics and their morphological variation. METHODS: Twenty-one nonpaired fresh frozen human cadaveric knees (from whole leg) were used for the analysis of PKF and DKF through an anterolateral approach. The anatomical relationships between the adjacent anterolateral structures were reported and anatomical characteristics of PKF and DKF (thickness, width and length) measured at 50° knee flexion under different rotational conditions (neutral: NR, Internal at 5Nm: IR applied with a dynamometric torque rig). Bony ridges of PKF and DKF were measured. RESULTS: PKF and DKF and their respective bony ridges were individually identified in all knees studied (n = 21). The PKF and DKF were proximal and posterior to the lateral femoral epicondyle, respective distances 49.20 ± 7.38 and 27.54 ± 7.69 mm. DKF were thicker (p < 0.001), wider (p < 0.001) and longer (p < 0.001) than the PKF, regardless of the tibial rotation applied. Tensioning of KF was achieved in IR with a decrease in thickness and width, alongside fiber lengthening (p < 0.001). CONCLUSION: PKF and DKF are distinct and constant anatomical structures of the lateral compartment of the knee, whose anatomical characteristics and their tensioning in IR presume a function of controlling rotational knee stability.

Mismatched knee implants in Indonesian and Dutch patients: a need for increasing the size.

PURPOSE: The aim of this study was to evaluate the anthropometric differences between knees of Indonesian Asians and Dutch Caucasians and the fit of nine different knee implant systems. METHODS: A total of 268 anteroposterior (AP) and lateral knee preoperative radiographs from 134 consecutive patients scheduled for total knee arthroplasty at two different centres in Jakarta and Leiden were included. Both patient groups were matched according to age and sex and included 67 Asians and 67 Caucasians. We assessed the radiographic differences between the Asian and Caucasian anthropometric data. The dimensions of the nine knee implant designs (Vanguard, Genesis II, Persona Standard, Persona Narrow, GK Sphere, Gemini, Attune Standard, Attune Narrow, and Sigma PFC) were compared with the patients' anthropometric (distal femur and proximal tibia) measurements. RESULTS: The Dutch Caucasian patients had larger mediolateral (ML) and AP femoral and tibial dimensions than the Indonesian Asians. The aspect ratios of the distal femur and tibia were larger in Asians than in Caucasians. The AP and ML dimensions were mismatched between the tibial components of the nine knee systems and the Asian anthropometric data. Both groups had larger ML distal femoral dimensions than the knee systems. CONCLUSION: Absolute and relative differences in knee dimensions exist not only between Asian and Caucasian knees but also within both groups. Not all TKA systems had a good fit with the Asian and Caucasian knee phenotypes. An increase in the range of available knee component sizes would be beneficial, although TKA remains an adequate compromise. LEVEL OF EVIDENCE: III.

Clinical studies of single-stage combined ACL and PCL reconstruction variably report graft tensioning, fixation sequence, and knee flexion angle at time of fixation.

PURPOSE: In single-stage ACL-PCL reconstruction, there is uncertainty regarding the order of graft tensioning and fixation, as well as the optimal knee flexion angle(s) for graft fixation. A systematic review of clinical studies of single-stage combined ACL-PCL reconstruction was performed to determine whether a particular fixation sequence and/or knee flexion angle is associated with superior outcomes. METHODS: A systematic review was performed according to PRISMA guidelines. All levels of evidence were included. All outcome measures were extracted, including physical examination values, radiographic measurements, and objective and subjective outcomes. RESULTS: Of the 19 included studies, 17 tensioned and fixed the PCL before the ACL. Only four studies reported the methods/forces used for graft tensioning. Across studies, the ACL was fixed at variable knee flexion angles, from full extension to 70°. Conversely, 3 studies fixed the PCL at a knee flexion angle < 45°, while the remaining 16 studies fixed the PCL at a flexion angle > 70°. Patient-reported outcomes were qualitatively similar between groups. CONCLUSIONS: This systematic review found considerable variability in graft tension, fixation sequence, and knee flexion angle at the time of fixation, with insufficient evidence to support specific surgical practices. Most commonly, the PCL is fixed before the ACL graft, with fixation occurring at a knee flexion angle between 70° and 90° and near full extension, respectively. The methodology for quantifying the forces applied for graft tensioning is rarely described. Given this clinical equipoise, future studies should consistently report these surgical details. Furthermore, prospective, randomized studies on the treatment of multiligament knee injuries are needed to improve outcomes in patients. LEVEL OF EVIDENCE: IV.

Is the plantaris muscle the most undefined human skeletal muscle?

The plantaris muscle is located in the posterior aspect of the superficial compartment of the lower leg, running from the lateral condyle of the femur to the calcaneal tuberosity. Classically, it is characterized by a small and fusiform muscle belly, which then changes into a long slender tendon. From the evolutionary point of view, the muscle is considered vestigial. However, it has recently been suspected of being a highly specialized sensory muscle because of its high density of muscle spindles. It has a noticeable tendency to vary in respect of both origin and insertion. Researchers have published many reports on the potential clinical significance of the muscle belly and tendon, including mid-portion Achilles tendinopathy, 'tennis leg syndrome', and popliteal artery entrapment syndrome. The right knee joint area was subjected to classical anatomical dissection, during which an atypical plantaris muscle was found and examined in detail. Accurate morphometric measurements were made. The muscle belly was assessed as bifurcated. Morphologically, superior and inferior parts were presented. There was a tendinous connection (named band A) with the iliotibial tract and an additional insertion (named band B) to the semimembranosus tendon. Both bands A and B presented very broad fan-shaped attachments. The human plantaris muscle is of considerable interest and has frequent morphological variations in its proximal part. Its specific characteristics can cause clinical problems and lead to confusion in diagnosis. More studies are needed to define its actual features and functions.

Modified Serum ALP Values and Timing of Apparition of Knee Epiphyseal Ossification Centers in Preterm Infants with Cholestasis and Risk of Concomitant Metabolic Bone Disease of Prematurity.

The usefulness of serum alkaline phosphatase (ALP) and phosphorous in screening and monitoring of metabolic bone disease of prematurity (MBDP) still has some limitations, especially in preterm infants with concomitant conditions such as cholestasis. We aimed to assess a modification of serum ALP (M-ALP) as a biomarker for MBDP in preterm infants, and the use of ultrasound monitoring for the apparition of knee ossification centers as marker of bone mineralization. Biochemical and clinical registers were taken from 94 preterm newborns <32 weeks. A significant correlation existed between serum ALP and direct bilirubin (DB), expressed by the regression equation: M-ALP (IU/L) = 302.1 + 96.9 (DB (mg/dL)). The ratio ALP/M-ALP > 1 was demonstrated to be more specific (87.5%) in the diagnosis of MBDP than the cut-off value of serum ALP > 500 IU/L (62.5%). ALP/M-ALP > 1 showed 100% sensitivity and specificity for the diagnosis of MBDP, and a good correlation with specific bone ALP (B-ALP). Patients with the knee nucleus by post-menstrual week 37 had lower B-ALP compared to patients with no nucleus, and no patients with MBDP presented the nucleus by the 40th week. In the absence of reliable specific B-ALP, reinterpreting serum ALP values by M-ALP plus monitoring of knee ossification centers contribute to better management of MBDP in preterm infants with cholestasis.

Kidney segmentation in neck-to-knee body MRI of 40,000 UK Biobank participants.

The UK Biobank is collecting extensive data on health-related characteristics of over half a million volunteers. The biological samples of blood and urine can provide valuable insight on kidney function, with important links to cardiovascular and metabolic health. Further information on kidney anatomy could be obtained by medical imaging. In contrast to the brain, heart, liver, and pancreas, no dedicated Magnetic Resonance Imaging (MRI) is planned for the kidneys. An image-based assessment is nonetheless feasible in the neck-to-knee body MRI intended for abdominal body composition analysis, which also covers the kidneys. In this work, a pipeline for automated segmentation of parenchymal kidney volume in UK Biobank neck-to-knee body MRI is proposed. The underlying neural network reaches a relative error of 3.8%, with Dice score 0.956 in validation on 64 subjects, close to the 2.6% and Dice score 0.962 for repeated segmentation by one human operator. The released MRI of about 40,000 subjects can be processed within one day, yielding volume measurements of left and right kidney. Algorithmic quality ratings enabled the exclusion of outliers and potential failure cases. The resulting measurements can be studied and shared for large-scale investigation of associations and longitudinal changes in parenchymal kidney volume.

Western-designed total knee implants mismatch Saudi patient knees. Anatomical bony measurements documented by computed tomography.

OBJECTIVES: To determine the anthropometric features of Saudi knees compared with knees of other ethnicities and reveal mismatches among different knee implant systems. METHODS: All knee computed tomography images obtained between January 2016 and September 2016 for varying medical reasons in a tertiary care hospital in Southwestern Saudi Arabia were retrospectively evaluated. Patients aged less than 18 years, with trauma or soft tissue or bone tumors were excluded.  Eleven parameters were measured for each knee joint. RESULTS: We evaluated 100 knees of 50 Saudi patients (25 men, 25 women) aged 28-85 (mean, 57.3) years. No statistically significant differences were found in age and Sasaki angle measurements between male and female patients. All other parameters were significantly larger in male than female knees. Our measurements were close to those published for Chinese, Thai, and Korean patients; however, published measurements were larger for Caucasian and Indian knees than our measurements. CONCLUSION: The Saudi population has morphological features of knee bone anatomy that do not match with the widely available prostheses designed for Caucasian knees. As several studies of different ethnicities have documented considerable prosthesis mismatch; our study further indicates the need for new implant designs that take these variations into account.