Femorotibial Joint Research Articles

Resistance of the Collateral Ligaments of the Femorotibial Joint in Domestic Dogs (Canis lupus familiaris LINNAEUS, 1758)

Introduction This work aimed to demonstrate the resistance of the femoral-tibial joint collaterals of 60 dogs of undefned breed, euthanized at the Zoonoses Control Centre of the city of Petrolina (PE), North-Eastern Brazil. Materials and Methods The femur-tibial articulation was dissected to expose the collateral ligaments. Bones were cut on the distal third of the femur and the proximal third of tibia and fibula. The knee joint was kept bound only by the collateral ligaments and then submitted to destructive mechanical tests, evaluating the deformation of the ligaments (mm) per unit of time, (seconds), and the joint resistance. Results We could observe no side effects of contralateral joints. In a destructive mechanical assay, we detected that the medial collateral ligaments ruptured earlier than the lateral ones. The resistance of the lateral and medial ligament of the right limb of females was respectively 537.1N ± 413.6 and 360.1N ± 228.6; while in males, were of 632.4N ± 333.4 e 440.4N ± 227.1. About the left antimere, the females presented 442.4N ± 288 resistance on the lateral ligament and 417.4N ± 190.6. In males, the resistance was 605.8N ± 316.1 e 548.6N ± 2,333.7, respectively. Conclusion The results of our research will allow the development of synthetic tissues to replace the natural ligament of dogs in cases of rupture or degeneration.

Leg deformation during imaginal ecdysis in the downy emerald, Cordulia aenea (Odonata, Corduliidae)

A dragonfly larva migrates from the water to the shore, perches on a plant stem and grasps it with strongly flexed legs. Adult legs inside the larval exoskeleton fit to the larval legs joint-to-joint. The adult emerges with stretched legs. During the molt, an imaginal leg must follow all the angles in exuvial joints. In turn, larval apodemes are withdrawn from imaginal legs. We visualized transient shapes of the imaginal legs by the instant fixation of insects at different moments of the molt, photographed isolated exuvial legs with the imaginal legs inside and then removed the exuvial sheath. Instant shapes of the imaginal tibia show sharp intrapodomere bends copying the angle in the larval femoro-tibial joint. The site of bending shifts distad during the molt. This is possible if the imaginal leg is pliable. The same problem of leg squeezing is also common in hemimetabolous insects as well as in other arthropods, whereas holometabolous insects overcome problems of a tight confinement either by using leg pliability in other ways but not squeezing (cyclorrhaphan flies, mosquitoes) or by pulling hardened legs out without change of their pupal zigzag configuration (moths, ants, honey bees). The pupal legs are not intended to grasp any external substrate.

Potential pharmaceutic effect of Shilajit (mumie) on experimental osteoarthritis in rat

Osteoarthritis (OA) is a worldwide joint disease with clinically loss of motion and pain in human. The conventional treatments are associated with essential side effects. In folk medicine, Shilajit is applied for treatment of arthritis and bone fractures. The present study evaluated effect of Shilajit on the osteoarthritis in rat model. Thirty-six adult male rats were randomly divided into two groups including OA and treated with Shilajit groups. OA was induced by injection of monosodium iodoacetate in the articular space of femorotibial joint. Aqueous extract of Shilajit was given to the treatment group by gavage as daily during experimental course until 21 days. The joint samples were investigated 7, 14, and 21 days post induction. The main macroscopic changes in the affected joints were swelling and congestion at early stages. Histopathologic study showed surface irregularity, erosion and fissures, necrotic chondrocytes, depletion of toluidine blue staining, and lysis of subchondral bone in both OA and Shilajit groups after 7 and 14 days. Synovium revealed synovial cells hyperplasia and inflammatory cells infiltration. Moderate to advanced OA was seen in both groups without significant difference. After 21 days, histopathologic scores of destructive damages and synovitis were reduced in the Shilajit group and showed significant difference in compare to OA group. The present study shows that aqueous extract of Shilajit decreased cartilage degenerative changes in knee osteoarthritis. Also, it reduced inflammatory reactions in synovial membrane.

Correlations between osteoartritis grading in femorotibial joint (kellgren lawrence) with cartilage defects grading

Background : Osteoarthritis (OA) is the most common chronic rheumatic diseases that causing pain and disability. The imaging of knee OA were found in 15,5% men and 12,7% women of Indonesia population. Radiography is still used as a standard modalities in assesing OA progression, and Kellgren-Lawrence scale (KL) is the most common measurement used byclinicians. Superficial cartilage degradation is the first sign of OA, the early detection of the superficial cartilage degradation is very important for diagnosis. Our study was established to assess the correlation between OA grading in femorotibial joint examined by standard Kellgren-Lawrence scale (KL) measurement with cartilage defects examined by ultrasound.Methods : Observational analytic study with cross sectional and consecutive sampling was performed. Rank Spearman test for correlation of OA grading, cartilage defect, BMI and joint malalignment. McNemar test for correspondence between the location of the narrowing of the femorotibial joint and location of cartilage defects.Result : Correlation of OA grading of femorotibial joints (KL) with cartilage defects grading on ultrasound resulted r =0.459, p<0.05; correlation of OA grading of femorotibial joints (KL) with BMI or joint malalignment resulted p>0,05; correlation of cartilage defect grading with BMI or joint malalignment also resulted p>0.05. McNemar test for location of the narrowing of thefemorotibial joint with location of cartilage defects on ultrasound resulted p = 1.00, k = 0.714. There was a significant positive correlation of OA grading of femorotibial joints (KL) with cartilage defects grading on ultrasound. There was no significant correlation between OA grading of femorotibial joints (KL) with BMI and joint malignment, and no significant correlationbetween cartilage defects grading with BMI and joint malalignment. There is a correspondence between the location of the narrowing of the femorotibial joint with location of cartilage defects on ultrasound.Conclusion: For assesing the grade of osteoartritis, cartilage defect grading and assesment by ultrasound can be used as an alternative to X-Ray KellgrenLawrence scale (KL) measurement.Keywords : femorotibial joint, cartilage defects grading, osteoartritis grading examination, BMI, joint malalignment.

Degenerative changes after posterior cruciate ligament reconstruction are irrespective of posterior knee stability: MRI-based long-term results.

Posterior cruciate ligament reconstruction (PCLR) is advocated to prevent an early onset of osteoarthritis. We hypothesized that posterior instability after PCLR correlates with degenerative changes. MRIs of 42 (12 female/30 male; 39 ± 9years) patients were enrolled with a minimum 5-year follow-up (FFU) after PCLR. In addition, 25 contralateral and 15 follow-up MRIs (12months after baseline) were performed. Degenerative changes were graded using WORMS. Posterior tibial translation (PTT) was measured using posterior stress radiographs. Outcome parameters included WORMS/cartilage subscore for the whole joint, patellofemoral (PFJ), medial (MFTJ), and lateral femorotibial joint (LFTJ). Final follow-up was 101 (range 68-168) months. WORMS reached 41.5 [18.5-56.8]. Regional WORMS for PFJ was significantly higher than MFTJ and LFTJ. Cartilage subscore yielded 7 [2.8-15]. MFTJ and PFJ were significantly higher than LFTJ. Primary outcome parameters were significantly higher than the contralateral knee (P < 0.0001) and significantly increased within 12months (P = 0.0002). There was a significant correlation between the intraoperative degree of cartilage injury and WORMS (P < 0.0001 with r = 0.64) and between the number of previous surgery and the cartilage subscore (P = 0.03 with r = 0.32). Meniscal surgery led to a significantly higher WORMS (P = 0.035). Combined risk models revealed that women below the mean age had significantly lower WORMS (P = 0.001) and cartilage subscores (P = 0.003). Patients undergo degenerative changes after PCLR, which are significantly higher compared to the contralateral knee. These occur predominantly at PFJ/MFTJ and are irrespective of posterior stability. Concomitant meniscus/cartilage injuries and a high number of previous surgeries are further risk factors.

Biodistribution and Immunogenicity of Allogeneic Mesenchymal Stem Cells in a Rat Model of Intraarticular Chondrocyte Xenotransplantation.

Xenogeneic chondrocytes and allogeneic mesenchymal stem cells (MSC) are considered a potential source of cells for articular cartilage repair. We here assessed the immune response triggered by xenogeneic chondrocytes when injected intraarticularly, as well as the immunoregulatory effect of allogeneic bone marrow-derived MSC after systemic administration. To this end, a discordant xenotransplantation model was established by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats and monitoring the immune response. First, the fate of MSC injected using various routes was monitored in an in vivo imaging system. The biodistribution revealed a dependency on the injection route with MSC injected intravenously (i.v.) succumbing early after 24 h and MSC injected intraperitoneally (i.p.) lasting locally for at least 5 days. Importantly, no migration of MSC to the joint was detected in rats previously injected with PAC. MSC were then administered either i.v. 1 week before PAC injection or i.p. 3 weeks after to assess their immunomodulatory function on humoral and adaptive immune parameters. Anti-PAC IgM and IgG responses were detected in all PAC-injected rats with a peak at week 2 postinjection and reactivity remaining above baseline levels by week 18. IgG2a and IgG2b were the predominant and long-lasting IgG subtypes. By contrast, no anti-MSC antibody response was detected in the cohort injected with MSC only, but infusion of MSC before PAC injection temporarily augmented the anti-PAC antibody response. Consistent with a cellular immune response to PAC in PAC-injected rats, cytokine/chemokine profiling in serum by antibody array revealed a distinct pattern relative to controls characterized by elevation of multiple markers at week 2, as well as increases in proliferation in draining lymph nodes. Notably, systemic administration of allogeneic MSC under the described conditions did not diminish the immune response. IL-2 measurements in cocultures of rat peripheral blood lymphocytes with PAC indicated that PAC injection induced some T-cell hyporesponsiveness that was not enhanced in the cohorts additionally receiving MSC. Thus, PAC injected intraarticularly in Lewis rats induced a cellular and humoral immune response that was not counteracted by the systemic administration of allogeneic MSC under the described conditions.

Morphometric Studies on the Femorotibial Joint in Cattle

Morphometric Studies on the Femorotibial Joint in Cattle

A technique of needle redirection at a single craniolateral site for injection of three compartments of the equine stifle joint.

OBJECTIVE To determine accuracy for a technique of needle redirection at a single craniolateral site for injection of 3 compartments of the equine stifle joint, describe the external needle position, and identify the location of the needle tip within each joint compartment. SAMPLE 24 equine cadaver stifle joints. PROCEDURES Stifle joints were placed in a customized stand. After the needle was placed, external needle position was measured and recorded. Each joint compartment (medial and lateral compartments of the femorotibial joint and the femoropatellar joint) was injected with a solution containing iodinated contrast medium, water, and dye. Radiography, assessment of intra-articular location of the needle tip, and gross dissection were performed to determine success of entering each joint compartment. Student t tests and an ANOVA were used to compare mean values. RESULTS Overall accuracy was 19 of 24 (79.1%), and accuracy for individual joint compartments was at least 21 of 24 (87.5%). Mean depth of needle insertion to access each compartment of the stifle joint was 5.71 cm. Mean angle of insertion (relative to the long axis of the tibia) was 82.1°, 80.3°, and 18.5° for the medial compartment of the femorotibial joint, lateral compartment of the femorotibial joint, and femoropatellar joint, respectively, and 28° medial, 7.3° lateral, and 1.3° lateral for the medial compartment of the femorotibial joint, lateral compartment of the femorotibial joint, and femoropatellar joint, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results supported that this was an accurate technique for successful injection of the 3 equine stifle joint compartments.

Bone morphological factors influencing cartilage degeneration in the knee

Objectives: Morphological features of the distal femur and proximal tibia associated with cartilage degeneration are unknown. This study aimed to elucidate local anatomical parameters of the knee which correlate with articular cartilage degeneration using MRI T1ρ mapping.Methods: This study involved 200 subjects with knee pain (mean age, 48.7 years; range, 14–80 years) with no severe osteoarthritic changes on plain X-ray. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of medial and lateral posterior tibial slope (MTS, LTS) and medial and lateral femoral condylar offset ratio (MFCOR, LFCOR) was performed using sagittal proton density-weighted imaging. Morphological assessment of posterior root and horn of menisci was also performed according to a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) of the knee.Results: Multiple regression analysis revealed that a decrease in MTS was associated with increased T1ρ values in the medial tibia, independent of age, osteoarthritic changes on plain X-ray, femur-tibia angle (FTA), and posterior medial meniscal lesions.Conclusions: Shallow MTS correlates with cartilage degeneration in symptomatic patients. This parameter could help in understanding the etiology of osteoarthritis in the early stage. Future kinematic studies will be needed to confirm our findings.

Patellofemoral kinematics in dogs with cranial cruciate ligament insufficiency: an in-vivo fluoroscopic analysis during walking

BackgroundComplete rupture of the cranial cruciate ligament (CrCL) in dogs causes profound disturbance to stifle joint biomechanics. The objective of this study was to characterize the effects of cranial cruciate ligament (CrCL) insufficiency on patellofemoral (PF) kinematics in dogs during walking. Ten client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Dogs underwent computed tomographic scans to create digital bone-models of the patella and femur. Lateral projection fluoroscopy of the stifles was performed during treadmill walking. Sagittal plane PF kinematics were calculated throughout the gait cycle by overlaying digital bone models on fluoroscopic images using a previously described 2D-3D registration technique. For acquisition of kinematics in the contralateral (control) stifle, fluoroscopy was repeated 6-months after stabilizing surgery of the affected side. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative control stifles.ResultsCraniocaudal PF translation was similar between CrCL-deficient and control stifles throughout the gait cycle. The patella was more distal and positioned in greater flexion throughout the gait cycle in CrCL-deficient stifles when compared to the control stifle at equivalent time points. There was no significant difference in PF poses between CrCL-deficient and control stifles at equivalent femorotibial flexion angles; however, common femorotibial flexion angles were only found over a small range during the swing phase of gait.ConclusionsCrCL insufficiency altered PF kinematics during walking, where the changes were predominately attributable to the femorotibial joint being held in more flexion. Abnormal PF kinematics may play a role in the development of osteoarthritis that is commonly observed in the PF joint CrCL-deficient stifles.

Fracture of the medial intercondylar eminence of the tibia in horses treated by arthroscopic fragment removal (21 horses).

SummaryBackgroundFractures of the medial intercondylar eminence of the tibia (MICET) are scarcely reported in horses.ObjectivesTo report the clinical and diagnostic findings, surgical treatment and outcome in a series of horses presented with MICET fracture and treated with arthroscopic fragment removal.Study designMulticentre retrospective case series.MethodsCase records of horses diagnosed with MICET fractures that had undergone surgical treatment were reviewed. Follow‐up information was obtained from re‐examination visits and/or owners.ResultsTwenty‐one cases were identified at 9 equine hospitals between 2004 and 2016. A history of trauma and acute onset of lameness was reported in 12 horses. All cases underwent fracture removal via arthroscopy of the medial femorotibial joint. The cranial cruciate ligament was intact in 6 horses and damaged in 15 horses (damage was ≤25% [n = 9], 25–50% [n = 4] or ≥50% [n = 2] of the cross‐sectional area). The cranial ligament of the medial meniscus was damaged in 11 horses (≤25% [n = 8], 25–50% [n = 3]). The medial meniscus was damaged in 5 horses and articular cartilage damage was identified in 14 horses (mild [n = 8], moderate [n = 6]). Follow‐up information (median 14 months; 4 months–6 years) was available for 20 cases; 2 horses were sound but convalescing; 13 horses were sound and returned to their previous or expected use. Of the 4 horses with the most severe changes to the articular soft tissue structures, 2 remained lame and 2 were subjected to euthanasia because of persistent lameness.Main limitationsThe retrospective, multicentre nature of this study and the limited number of horses are the main limitations.ConclusionsFractures of the MICET are commonly associated with a traumatic event. Prompt diagnosis and early arthroscopic removal of the fracture are recommended.

Equine meniscal degeneration is associated with medial femorotibial osteoarthritis.

There is limited information available concerning normal equine meniscal morphology, its degeneration and role in osteoarthritis (OA). To characterise normal equine meniscal morphology and lesions and to explore the relationship between equine meniscal degeneration and femorotibial OA. Ex vivo cadaveric study. Menisci were harvested from 7 normal joints (n = 14 menisci) and 15 joints with OA (n = 30 menisci). A macroscopic femorotibial OA score (cartilage degeneration and osteophytosis) was employed to measure disease severity in each compartment. The femoral and tibial meniscal surfaces were scored for macroscopic fibrillation and tears (1-4). Histological sections (regions: cranial and caudal horn; body) were also scored for microscopic fibrillation and tears (0-3) and inner border degeneration (0-3). Partial meniscal tears were present on both femoral and tibial surfaces in all 3 regions and most frequently identified on the femoral surface of the cranial horn of the medial meniscus and body of the lateral meniscus. There was a significantly positive correlation between the global medial meniscal macroscopic scores and osteophyte (r = 0.7, P = 0.002) or cartilage degeneration (r = 0.5, P = 0.03) scores within the medial femorotibial joint. The global medial meniscal macroscopic score was greater (P = 0.004) in the advanced OA joints compared with control joints. The menisci were principally from abattoir specimens without a known clinical history because of the challenge in obtaining a large number of specimens with a clinical diagnosis of femorotibial OA. This study is the first to describe normal equine meniscal morphology and lesions. Meniscal lesions were identified in all segments and on both articular surfaces. Meniscal degeneration significantly correlated with OA severity in the equine medial femorotibial joint. The relationship between OA and meniscal pathology remains to be elucidated.

Correlation of medial compartmental joint line elevation with femorotibial angle correction and clinical function after unicompartmental arthroplasty

To study the correlation of postoperative femorotibial angle with medial compartmental joint line elevation after unicompartmental arthroplasty(UKA), as well as the correlation of joint line elevation with the clinical function by measuring radiological joint line. A retrospective study of 56 patients from July 2012 to August 2015 was performed. The mean body mass index (BMI) was 23.5 (ranged, 18.3 to 30.1). The standing anteroposterior radiographs of these patients were assessed both pre-and post-operatively, and the knee function was evaluated according to HSS grading. The correlation between postoperative femorotibial angle(FTA) and joint line elevation was analyzed as well as the correlation between joint line elevation and the clinical function. The mean medial joint line elevation was (2.2±2.0) mm(ranged, -3.3 to 7.0 mm), and the mean FTA correction was (2.3±3.0)°(ranged, -4.5° to 9.6°). The mean follow-up period was 12.2 months. There was a significant correlation between in joint line elevation and FTA correction(P<0.05), while there was no significant correlation between joint line elevation and the clinical function(P>0.05). There was a significant correlation between medial compartmental joint line elevation and FTA correction after UKA, and the proximal tibial osteotomy was critical during the procedure. There was no significant correlation between joint line elevation and the clinical function, which may be related to the design of UKA prosthesis.

The Role of Micrornas in Osteoarthritis and Ageing-Related Functional Decline in Joint Tissue Homeostasis

Purpose: Osteoarthritis is a degenerative disease associated with changes in the articular cartilage and bone, severely affecting patients' mobility and quality of life. A similar, but less acute decline is also seen during ageing. microRNAs (miRs) are novel post-transcriptional regulators of gene expression. microRNAs have been implicated in different aspects of musculoskeletal ageing through their differential expression, however the functional consequences of this are still not fully understood. Methods: Wild type C57BL6/J adult (3–6 months old) mice and human cartilage explants from knee replacement surgeries were used. To study microRNA function in vivo, modified microRNA antagomiR was delivered via intraarticular injection into knee joints of mice or via transfection into the human explants. Knee joints were dissected for histological assessment or RNA isolation. Human cartilage explants were cultured with IL-1β, miR mimic and/or antagomiR. Fixed joints and explants were subsequently decalcified and processed for wax embedding. Serial coronal sections were stained with Safranin O at regular intervals across the joint, and scored for articular cartilage degradation severity, using the OARSI grading system (from grades 0–6). RNA was used for microRNA and mRNA profiling using high-throughput sequencing and subsequently qPCR. Results: Our data shows dysregulation of miR-199 in human and mouse models of OA. Using qPCR and luciferase assays, we validated a selection of the microRNAs target genes differentially expressed in mouse femorotibial joints and human cartilage explants models of OA. miR-199 was further analysed using in vitro and in vivo gain- and loss-of-function approaches. Conclusions: In summary, we have shown the regulation of OA-associated target genes by miR-199 in the in vitro and in vivo models of OA and have shown that dysregulation of miR-199 expression may contribute to the pathogenic phenotype in the OA models. The authors would like to acknowledge financial support from the MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA) and BBSRC.

The effect of intraarticular serum rich in growth factors (SRGF) on knee osteoarthritis in the rat model

Osteoarthritis (OA) is a degenerative joint disease with high incidence in world. Various treatments have been used for decreasing pain and improving physical function without clearly beneficial evidences. Nowadays, platelet-rich therapy is used as a novel approach in field of regenerative medicine. The present study evaluated the effect of intraarticular serum rich in growth factors (SRGF) on the monosodium iodoacetate induced-osteoarthritis in rat model. SRGF was injected 3 times weekly. Femorotibial joints were examined 2 weeks after last injection. Histopathologic results showed remarkable articular regeneration in the SRGF treated rats. Our findings were less surface irregularities and articular clefts, proliferation of chondrocytes and increasing synthesis of matrix proteoglycan with toluidine blue staining. Destroyed articular cartilage was repaired by fibro-hyaline cartilage in contrast to the OA rats that filled with fibrovascular tissues. The microscopic score had decreased in the treatment group. We concluded that SRGF, as a source of growth factors, have chondroinductive capacity with regard to enhancement of cartilage regeneration.

MRI findings of knee abnormalities in adolescent and adult volleyball players

BackgroundTo longitudinally and cross-sectionally evaluate knee abnormalities by sex and age in adolescent and adult volleyball athletes over 2 years using magnetic resonance imaging (MRI).MethodsThirty-six high-level volleyball athletes (18 adolescents: 56% female, mean age 16.0 ± 0.8 years; and 18 adults: 50% female, mean age 46.8 ± 5.1 years) were imaged by MRI at BL and at 2-year follow-up (FU). Prevalence and severity of cartilage lesions, subarticular bone marrow lesions (BMLs), subarticular cysts, osteophytes, and ligament and meniscus integrity were evaluated by sex and by age cohort (adolescents and adults) using the whole-organ MRI score (WORMS).ResultsThere were no significant longitudinal changes in any of the features within any of the sex or age groups. No significant differences were found in overall prevalence or severity of any of the features between males and females, although at FU, males had a significantly higher prevalence of osteophytes in the medial femorotibial joint (MFTJ) than females (p=0.044). Compared to adolescents, adult volleyball players had a significantly greater prevalence and severity of cartilage lesions (p<0.001 for both), BMLs (p=0.0153 and p=0.005), and osteophytes (p≤0.003 and p<0.001), and more severe meniscal lesions (p≤0.021).ConclusionWe found significant differences in the prevalence and severity of knee abnormalities between adolescent and adult volleyball players, but no overall differences by sex. These findings lay the groundwork for further investigations with larger cohorts and longer FU times to determine whether or not these knee abnormalities are associated with the development of OA.

Tibial condylar valgus osteotomy (TCVO) for osteoarthritis of the knee: 5-year clinical and radiological results

PurposeTibial condylar valgus osteotomy (TCVO) is a type of opening-wedge high tibial osteotomy for advanced medial knee osteoarthritis (OA) with subluxated lateral joint. We report the concept, the current surgical technique with a locking plate, and the short-term clinical and radiological results of this procedure.Methods11 knees with medial OA and a widened lateral joint were treated by TCVO (KL stage III: 6, IV: 5). In this procedure, by the L-shaped osteotomy from the medial side of the proximal tibia to the intercondylar eminence and the valgus correction, lateralization of the mechanical axis and reduction of the subluxated lateral joint are obtained with early postoperative weight-bearing. Before, 6 months, 1, and 5 years after the operation, a visual analog scale (VAS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC), alignment of the lower extremity, and congruency and stability of the femorotibial joint were investigated.ResultsThe VAS improved from an average of 73 mm to 13 mm, and the total WOMAC score from 52 to 14 before to 5 years after the operation, respectively. The mechanical axis changed from 1 to 60%, and the FTA changed from 186° to 171°. The joint line convergence angle (JLCA) changed from 6° to 1°, and the angle difference of JLCA between varus and valgus stress improved from 8° to 4° after the procedure.ConclusionImprovements in pain and activities of daily living were observed by TCVO along with valgus correction of the lower extremity and stabilization of the femorotibial joint.

Take-off mechanisms in parasitoid wasps.

High-speed video analyses of the natural behaviour of parasitoid wasps revealed three strategies used to launch the insects into the air. Which strategy is the most energy efficient? In Pteromalus puparum, 92% of take-offs by were propelled entirely by movements of the middle and hind legs, which were depressed at their coxo-trochanteral and extended at their femoro-tibial joints. The front legs left the ground first, followed by the hind legs, so that the middle legs provided the final propulsion. Second, in other species of a similar mass, Cotesia glomerata and Leptopilina boulardi, all take-offs were propelled by a mean of 2.8 and 3.8wingbeats, respectively, with little or no contribution from the legs. The first strategy resulted in take-off times that were four times shorter (5 versus 22.8 ms) and take-off velocities that were four times faster (0.8 versus 0.2 m s-1). Calculations from the kinematics indicate that propulsion by the legs was the most energy-efficient strategy, because more energy is put into propulsion of the body, whereas in take-off propelled by repetitive wing movements energy is lost to generating these movements and moving the air. In heavier species such as Netelia testacea and Amblyteles armatorius, take-off was propelled by the combined movements of the middle and hind legs and wingbeats. In A. armatorius, this resulted in the longest mean take-off time of 33.8 ms but an intermediate take-off velocity of 0.4 m s-1 In all three strategies the performance could be explained without invoking energy storage and power amplification mechanisms.

Ultrasound diagnosis of injuries of the cranial meniscotibial ligament of the medial meniscus

SummaryUltrasonographic examination of the femorotibial joint is now commonly performed for investigating hindlimb lamenesses. Different types of meniscal injuries have been described using this technique. In our practice, the cranial meniscotibial ligament of the medial meniscus (CrMTL‐MM) is the most frequently affected soft tissue structure of the stifle. This article describes the technique to image this ligament, normal images and the ultrasonographic manifestations of desmopathies and enthesopathies of the CrMTL‐MM.

The contribution of 3D quantitative meniscal and cartilage measures to variation in normal radiographic joint space width—Data from the Osteoarthritis Initiative healthy reference cohort

ObjectiveTo explore to what extent three-dimensional measures of the meniscus and femorotibial cartilage explain the variation in medial and lateral femorotibial radiographic joint space width (JSW), in healthy men and women. MethodsThe right knees of 87 Osteoarthritis Initiative healthy reference participants (no symptoms, radiographic signs or risk factors of osteoarthritis; 37 men, 50 women; age 55.0±7.6; BMI 24.4±3.1) were assessed. Quantitative measures of subregional femorotibial cartilage thickness and meniscal position and morphology were computed from segmented magnetic resonance images. Minimal and medial/lateral fixed-location JSW were determined from fixed-flexion radiographs. Correlation and regression analyses were used to explore the contribution of demographic, cartilage and meniscal parameters to JSW in healthy subjects. ResultsThe correlation with (medial) minimal JSW was somewhat stronger for cartilage thickness (0.54≤r≤0.67) than for meniscal (−0.31≤r≤0.50) or demographic measures (−0.15≤r≤0.48), in particular in men. In women, in contrast, the strength of the correlations of cartilage thickness and meniscal measures with minimal JSW were in the same range. Fixed-location JSW measures showed stronger correlations with cartilage thickness (r≥0.68 medially; r≥0.59 laterally) than with meniscal measures (r≤|0.32| medially; r≤|0.32| laterally). Stepwise regression models revealed that meniscal measures added significant independent information to the total variance explained in minimal JSW (adjusted multiple r2=58%) but not in medial or lateral fixed-location JSW (r2=60/51%, respectively). ConclusionsIn healthy subjects, minimal JSW was observed to reflect a combination of cartilage and meniscal measures, particularly in women. Fixed-location JSW, in contrast, was found to be dominated by variance in cartilage thickness in both men and women, with somewhat higher correlations between cartilage and JSW in the medial than lateral femorotibial compartment. The significant contribution of the meniscus’ position on minimal JSW reinforces concerns over validity of JSW as an indirect measure of hyaline cartilage.