Ischemic preconditioning of the muscle reduces the metaboreflex response of the knee extensors.

PURPOSE: This study investigated the effect of ischemic preconditioning (IP) on metaboreflex activation following dynamic leg extension exercise in a group of healthy participants. METHOD: Seventeen healthy participants were recruited. IP and SHAM treatments (3 × 5 min cuff occlusion at 220 mmHg or 20 mmHg, respectively) were administered in a randomized order to the upper part of exercising leg's thigh only. Muscle pain intensity (MP) and pain pressure threshold (PPT) were monitored while administrating IP and SHAM treatments. After 3 min of leg extension exercise at 70% of the maximal workload, a post-exercise muscle ischemia (PEMI) was performed to monitor the discharge group III/IV muscle afferents via metaboreflex activation. Hemodynamics were continuously recorded. MP was monitored during exercise and PEMI. RESULTS: IP significantly reduced mean arterial pressure compared to SHAM during metaboreflex activation (mean ± SD, 109.52 ± 7.25 vs. 102.36 ± 7.89 mmHg) which was probably the consequence of a reduced end diastolic volume (mean ± SD, 113.09 ± 14.25 vs. 102.42 ± 9.38 ml). MP was significantly higher during the IP compared to SHAM treatment, while no significant differences in PPT were found. MP did not change during exercise, but it was significantly lower during the PEMI following IP (5.10 ± 1.29 vs. 4.00 ± 1.54). CONCLUSION: Our study demonstrated that IP reduces hemodynamic response during metaboreflex activation, while no effect on MP and PPT were found. The reduction in hemodynamic response was likely the consequence of a blunted venous return.

Intra-articular venous malformations of the knee: a diagnostic challenge.

BACKGROUND: Intra-articular venous malformations (IAVM) are rare benign vascular anomalies that usually affect young patients and most common locate in the knee. The terminology of these lesions is still ill-defined, as they are often termed in the literature as synovial hemangiomas. Early diagnosis can be difficult, because they usually present with nonspecific clinical manifestations that are similar those of other rheumatic diseases, especially juvenile idiopathic arthritis (JIA). CASE SERIES: We conducted a retrospective analysis of five pediatric patients admitted to our units for recurrent swelling of the knee, and compared their characteristics with those of literature reports. The average age at first symptom and time from onset to diagnosis was 3.9 years (range 18 months-7 years) and 3.5 years (range 1-7 years), respectively. In our patients, an initial misdiagnosis of JIA, bleeding disorder or traumatic arthropathy was made. On MRI imaging, the features of the lesion were similar in all patients, and were marked by isointense-to-hypointense signal in T1-weighted images, and hyperintense signal in T2-weighted images. When performed, arthrocentesis led to aspiration of bloody fluid. The diagnosis was confirmed with a biopsy and histopathologic assessment in all patients. Open surgery enabled complete excision of the mass and was followed by stable remission over time in all cases. CONCLUSIONS: Our report highlights the challenges that may be posed by the detection of knee IAVM and the frequent long delay between onset of symptoms and diagnosis. The key elements for early recognition include careful assessment of patient history, demonstration of bloody fluid on arthrocentesis, and proper interpretation of MRI scanning.

Comparison of efficacy between the genicular nerve block and the popliteal artery and the capsule of the posterior knee (IPACK) block for total knee replacement surgery: A prospective randomized controlled study.

OBJECTIVE: The aim of this study was to compare the efficacy of popliteal artery and the capsule of the posterior knee (IPACK) block and genicular nerve block on postoperative pain scores, the need for rescue analgesics, range of motion (ROM), walking distance, and perioperative monitorization variables in patients undergoing total knee replacement (TKR) surgery. METHODS: Sixty American Society of Anesthesiologists (ASA) physical status I-III patients were enrolled in this study and then were randomly assigned into three groups: the IPACK block group (17 female, 3 male; mean age=67.5±1.4 years), genicular nerve block (16 female, 4 male; mean age=68±1.76 years), and the control group (13 female, 7 male; mean age=63±1.67years). All the patients underwent TKR under spinal anesthesia. The visual analog scale (VAS) score, mobility, pre- and intra-operative monitorization of systolic and diastolic holding area, non-invasive blood pressure, heart rate, and SPO 2 were compared between the groups. RESULTS: Patients in the IPACK and genicular block groups had a significantly lower visual analogous scale (VAS) at postoperative 4 hours (p<0.01), 8h (p<0.01), 12h (p<0.01), and 24h (p<0.05). VAS score was significantly lower in the genicular block group at the postoperative 4h (5.5±0.55) and 8h (5.0±0.53) in the mobile state compared to the IPACK (8.0±0.47 and 8.0±0.43, respectively) and the control group (9.5±0.20; 10±0.28, respectively) (p< 0.01). The use of patient-controlled-analgesia (PCA) devices and button push count for analgesics demand were significantly lower in the genicular block group on the immediate postoperative period (p<0.01 at the postoperative 0 to 4 h). The total consumption of morphine equivalents on the postoperative day 0 was significantly lower in the genicular block group (p<0.01, and p<0.001 for IPACK and control groups, respectively). The degree of flexion was significantly higher in the genicular block group at the postoperative 12h compared to the IPACK and the control group (p<0.001). The length of hospital stay was significantly lower in the genicular block group compared to the IPACK and the control group (p<0.05 for both variables). CONCLUSION: IPACK and genicular blocks both are effective in improving patient comfort during and after TKR surgery and reducing the potential need for systemic analgesic and opioids. The genicular block seems to be a promising technique that can offer improved pain management in the immediate and early postoperative period without adverse effects on systemic and motor variables.

Morphological and Histological Changes in the Human Anterior Cruciate Ligament after Rupture.

BACKGROUND: Injuries to the anterior cruciate ligament (ACL) are common and complete tears often fail to heal. ACL reconstruction is considered the surgical gold standard of care for ACL injuries in young active patients. OBJECTIVES: To determine the corresponding morphological and histological features of the torn ACL in different time periods after injury. METHODS: The study included 28 remnant specimens of torn ACLs from patients who had ACL reconstruction surgery of the knee. The remnant pathology was evaluated by its morphology during arthroscopy and by histopathologic measurements. RESULTS: At surgery there were three progressive and distinct morphological tear patterns. The first pattern was noticed within the first 3 months from injury and showed no scar tissue. The second pattern appeared later and was characterized by the appearance of scar tissue with adhesion to the femoral wall. The third pattern was characterized by adhesion of the ACL remnant to the posterior cruciate ligament. The histological changes of the first morphological pattern showed abundance of blood vessels and lymphocytes at the torn femoral end with few irregular collagen fibers. The second and third tear patterns showed decrement in the number of blood vessels and lymphocytes with longitudinally oriented collagen fibers. CONCLUSIONS: The morphological features of the ACL remnant in the first 3 months after injury showed no scar tissue and its histological features had the characteristics of a reparative phase. This phase was followed by a prolonged remodeling phase that ended with attachment of the remnant to the posterior cruciate ligament.

Physeal-sparing posteromedial portal approach reduced distance between guide pin and neurovascular structures.

PURPOSE: To compare a femoral physeal sparing anterior cruciate ligament (ACL) reconstruction technique utilizing a posteromedial portal to traditional transphyseal techniques with regards to anatomic tunnel positioning and proximity to important neurovascular structures. METHODS: Eight cadaveric knees were obtained for the study. Femoral tunnel guide pins were placed utilizing four different techniques: accessory anterior medial portal, posteromedial portal, trans-tibial, and figure-4 methods. The knees were then dissected and the following measurements taken: distance of each pin to the saphenous and peroneal nerve, popliteus tendon, neurovascular bundle, femoral ACL footprint and articular cartilage, and the angle of the guide pin entering the lateral femoral condyle. Fluoroscopic imaging was taken to determine the disruption of the physeal scar. RESULTS: Posteromedial portal guide pin was significantly closer to the neurovascular bundle, popliteal tendon and saphenous nerve when compared to the other 3 techniques, but was further from the peroneal nerve. It also had the smallest distance from the anatomic footprint of the ACL, and the largest angle to the lateral femoral condyle. The posteromedial portal guide pin had similar distance from the articular cartilage as the accessory anterior medial portal and figure-4 guide pin, with the trans-tibial guide pin being the farthest. The posteromedial portal guide pin failed to disrupt the physeal scar in all specimens, while the other three techniques consistently violated the physeal scar. CONCLUSION: The posteromedial portal technique offers an appropriate method for anatomic ACL reconstruction while protecting the distal femoral physis from injury. Care needs to be taken with this technique as it comes in closer proximity to some of the important neurovascular structures. This study indicates that posteromedial portal technique is a less technically challenging approach for physeal-sparing ACL repair with special attention required for the protection of neurovascular bundle from potential injury.

Mechanical loading stimulates bone angiogenesis through enhancing type H vessel formation and downregulating exosomal miR-214-3p from bone marrow-derived mesenchymal stem cells.

Exosomes are important transporters of miRNAs, which play varying roles in the healing of the bone fracture. Angiogenesis is one of such critical events in bone healing, and we previously reported the stimulatory effect of mechanical loading in vessel remodeling. Focusing on type H vessels and exosomal miR-214-3p, this study examined the mechanism of loading-driven angiogenesis. MiRNA sequencing and qRT-PCR revealed that miR-214-3p was increased in the exosomes of the bone-losing ovariectomized (OVX) mice, while it was significantly decreased by knee loading. Furthermore, compared to the OVX group, exosomes, derived from the loading group, promoted the angiogenesis of endothelial cells. In contrast, exosomes, which were transfected with miR-214-3p, decreased the angiogenic potential. Notably, knee loading significantly improved the microvascular volume, type H vessel formation, and bone mineral density and contents, as well as BV/TV, Tb.Th, Tb.N, and Tb.Sp. In cell cultures, the overexpression of miR-214-3p in endothelial cells reduced the tube formation and cell migration. Collectively, this study demonstrates that knee loading promotes angiogenesis by enhancing the formation of type H vessels and downregulating exosomal miR-214-3p.

Activation of Bone Remodeling Compartments in BMP-2-Injected Knees Supports a Local Vascular Mechanism for Arthritis-Related Bone Changes.

BACKGROUND: Synovial membrane-derived factors are implicated in arthritis-related bone changes. The route that synovial factors use to access subchondral bone and the mechanisms responsible for these bone changes remain unclear. A safety study involving intra-articular injection of bone morphogenetic protein-2 (BMP-2)/calcium phosphate matrix (CPM) or CPM addresses these issues. METHODS: Knee joints in 21 monkeys were injected with CPM or 1.5 or 4.5 mg/mL BMP-2/CPM and were evaluated at 1 and 8 weeks. Contralateral joints were injected with saline solution. Knee joints in 4 animals each were injected with 1.5 or 4.5 mg/mL BMP-2/CPM. Contralateral joints were injected with corresponding treatments at 8 weeks. Both joints were evaluated at 16 weeks. Harvested joints were evaluated grossly and with histomorphometry. Knee joints in 3 animals were injected with 125I-labeled BMP-2/CPM and evaluated with scintigraphy and autoradiography at 2 weeks to determine BMP-2 distribution. RESULTS: All treatments induced transient synovitis and increased capsular vascularization, observed to anastomose with metaphyseal venous sinusoids, but did not damage articular cartilage. Both treatments induced unanticipated activation of vascular-associated trabecular bone remodeling compartments (BRCs) restricted to injected knees. Bone volume increased in BMP-2/CPM-injected knees at 8 and 16 weeks. Scintigraphy demonstrated metaphyseal 125I-labeled BMP-2 localization restricted to injected knees, confirming local rather than systemic BMP-2 release. Autoradiography demonstrated that BMP-2 diffusion through articular cartilage into the metaphysis was blocked by the tidemark. The lack of marrow activation or de novo bone formation, previously reported following metaphyseal BMP-2/CPM administration, confirmed BMP-2 and synovial-derived factors were not free in the marrow. The 125I-labeled BMP-2/CPM, observed within venous sinusoids of injected knees, confirmed the potential for capsular and metaphyseal venous portal communication. CONCLUSIONS: This study identifies a synovitis-induced venous portal circulation between the joint capsule and the metaphysis as an alternative to systemic circulation and local diffusion for synovial membrane-derived factors to reach subchondral bone. This study also identifies vascular-associated BRCs as a mechanism for arthritis-associated subchondral bone changes and provides additional support for their role in physiological trabecular bone remodeling and/or modeling. CLINICAL RELEVANCE: Inhibition of synovitis and accompanying abnormal vascularization may limit bone changes associated with arthritis.

The Value of Preprocedural MR Imaging in Genicular Artery Embolization for Patients with Osteoarthritic Knee Pain.

PURPOSE: To determine the value of preprocedural MR imaging in genicular artery embolization (GAE) for patients with osteoarthritic knee pain. MATERIALS AND METHODS: This single-center study retrospectively analyzed 28 knees in 18 patients who underwent GAE for intractable knee pain < 1 month after MR imaging. The pain experienced in each knee was evaluated on a 100-mm visual analog scale (VAS) at baseline and 1- and 3-month after GAE. "GAE responders" were defined as knees that exhibited greater than 30% reduction of VAS pain scores from baseline at both follow-up visits. Musculoskeletal radiologists evaluated MR images of the affected knee compartment regarding cartilage defects, osteophytes, subchondral cysts, bone marrow lesions (BMLs), meniscal injury, and joint effusion. The performances of Kellgren-Lawrence (KL) grading and MR findings in predicting GAE responders was estimated based on receiver operating characteristic curves. RESULTS: The mean VAS pain score was 84.3 mm. BML (area under the curve [AUC], 0.860; P < .001), meniscal injury (AUC, 0.811; P = .003), and KL grading (AUC, 0.898; P < .001) were significantly associated with GAE outcome. To predict GAE responders, KL grade ≤ 2 yielded a sensitivity of 87.5% and a specificity of 60.9%, BML grade ≤ 1 yielded a sensitivity of 75.0% and a specificity of 69.6%, and meniscal injury grade ≤ 2 yielded a sensitivity of 83.3% and a specificity of 72.7%. CONCLUSIONS: Large BMLs and severe meniscal injuries on MR imaging, as well as high KL grades, indicated poor responses to GAE.

An anatomical neurovascular study for procedures targeting peri-articular nerves in patients with anterior knee pain.

BACKGROUND: Radiofrequency ablation (RFA) of the articular branches innervating the anterior knee capsule has been studied as a possible alternative to surgery for degenerative arthritis. However, the neurovascular topography of the anterior knee capsule remains unclear. METHODS: One leg from each of the 20 formalin-embalmed cadaveric specimens was investigated. Modified ablation points (MAPs) were evaluated for a possible alternative for conventional target points (CAPs). RESULTS: For the nerve to vastus medialis (NVM), the probability of identifying the nerve was higher at MAP compared with CAP (62.5% vs. 25%). The mean shortest distance from the nerve was shorter at MAP compared with CAP (18.0 mm vs. 29.9 mm). The probabilities and distances for other nerves were not significantly different between the points. However, the probability of identifying the artery was significantly lower at MAPs compared with CAPs for arteries (0%, 5.3%, and 0% vs. 84.2%, 84.2%, and 73.3% for superior medial genicular, superior lateral genicular, and inferior medial genicular artery, respectively). For the recurrent peroneal nerve (RPN), a new target point was set in MAPs. CONCLUSIONS: The current landmark for genicular nerve procedures may not accurately target the correct nerve position, or reduce the risk for vessel damage. A more proximal target may reduce complications and increase the probability of successful procedures, although clinical correlation is needed.

Exercise on a vibratory platform increases blood perfusion on the stifle joint and rectal temperature in healthy dogs / Exercício em plataforma vibratória aumenta a perfusão sanguínea da articulação do joelho e a temperatura retal de cães saudáveis

The effects of two vibration platform (VP) exercise protocols on stifle and rectal temperatures were evaluated. Eleven animals participated in two exercise protocols, different in duration in each exercise. Exercise protocol 1 (EP1) took 30 seconds and EP2, 60 seconds, with different vibratory levels in both cases (L1 = acceleration ≅ 1g, L4 = acceleration ≅ 2.5g, and L7 = acceleration ≅ 5g). The animals were evaluated before and 1 minute after the exercise, using infrared thermography to obtain stifle temperatures. The rectal temperature (RT) was also checked at each moment. The dogs had higher stifle temperatures in EP1 at all vibratory levels compared to the time before the exercise; EP2 resulted in higher temperature only at maximum vibration intensity (L7). Increase in TR was observed only in EP2. The results suggested that the short duration protocol (EP1) increased the muscular and peripheral vascular activities of the joint, regardless of the vibration intensity. The long duration protocol (EP2) with maximum vibration intensity increased the RT, demonstrating activity beyond the stifle muscle group. It is concluded that exercises on the VP can be used as complementary therapy for low-impact muscle activity in dogs and may be adequate for efficient energy consumption.(AU)

Foram avaliados os efeitos de dois protocolos de exercício em plataforma vibratória (PV) sobre as temperaturas dos joelhos e retais. Onze animais participaram de dois protocolos de exercício, diferentes na duração de cada exercício. O protocolo de exercício 1 (PE1) foi de 30 segundos e o PE2 foi de 60 segundos, com diferentes níveis vibratórios em ambos (L1 = aceleração ≅ 1g; L4 = aceleração ≅ 2,5g; e L7 = aceleração ≅ 5g). Os animais foram avaliados antes e um minuto após os exercícios, por meio de termografia infravermelha para a obtenção das temperaturas dos joelhos. A temperatura retal (TR) foi aferida em cada momento. Os cães apresentaram temperaturas dos joelhos mais elevadas em PE1, em todos os níveis vibratórios, em comparação a antes do exercício; o PE2 resultou em temperatura mais alta apenas na intensidade máxima de vibração (L7). Aumento na TR foi observado apenas no PE2. Os resultados sugerem que o protocolo de curta duração (PE1) aumentou as atividades muscular e vascular periférica da articulação, independentemente da intensidade da vibração; o protocolo de longa duração (PE2) com intensidade máxima de vibração aumentou a TR demonstrando atividade além do grupo muscular do joelho. Conclui-se que os exercícios na PV podem ser utilizados como terapia complementar para atividade muscular de baixo impacto em cães e pode ser adequada para o consumo eficiente de energia.(AU)

Intra-articular venous malformation of the knee in children: magnetic resonance imaging findings and significance of synovial involvement.

BACKGROUND: Intra-articular venous malformations of the knee are an uncommon cause of unilateral knee pain in children. Timely diagnosis is important because lesions with intrasynovial involvement can lead to joint space hemorrhage and secondary cartilage damage. OBJECTIVE: To describe our tertiary center's experience of diagnostics and typical magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: A retrospective review of all patients ≤16 years of age managed for intra-articular venous malformations of the knee at our institution between 2002 and 2018. RESULTS: Of 14 patients (8 male), the mean age at presentation was 6 years (range: 0-14 years). The most common clinical findings were unilateral knee pain (93%), joint swelling (79%), quadriceps atrophy (50%) and a limited range of motion (29%). Cutaneous manifestations were present in four patients (29%). Contrast-enhanced MRI was available in all cases. After initial MRI, a vascular anomaly etiology had been identified in 11 cases (79%), and correctly reported as a venous malformation in 6 (55%). Three patients received entirely different diagnoses (arthritis, tumor or pigmented villonodular synovitis). Three of seven patients with intrasynovial lesions had established chondropathy at diagnosis. Two patients with lesions of the suprapatellar fat pad had intrasynovial involvement that was not visualised on MRI. CONCLUSION: Although MRI usually permits the diagnosis, clinical awareness of these lesions is important for optimal imaging, accurate interpretation and timely diagnosis. Involvement of the intrasynovial cavity carries a risk of hemarthrosis and progressive chondropathy that may be underestimated by MRI.

Mapping the genicular arteries to provide a caution zone during knee surgery.

INTRODUCTION: Reports from the current literature show a lack of detail with depictions of the genicular arteries (GA). The intricate anatomy and infrequency of operating in the posterior knee may lead to surgeons being unfamiliar with the anatomy. The goal of this cadaveric study was to quantitatively map the arteries and create a caution zone that can be utilized when preparing and performing surgical procedures involving the knee. MATERIALS AND METHODS: The left knees of 46 cadavers were used. The distance of the GAs were from the joint line (JL) (+, superior to JL; -, inferior to JL) was measured in two locations: popliteal artery (PA) branch point and medial/lateral knee. The angle the artery traveled between these two points in the posterior knee was measured. A caution map was created. RESULTS: The superolateral GA branched from PA at +47.3 mm and traveled superiorly at 57.7° to +52.2 mm at the lateral knee. The superomedial GA branched from PA at +55.2 mm and traveled superiorly at 66.8° to +57.3 mm at the medial knee. The inferolateral GA branched from PA at -0.6 mm. It traveled superiorly at 74.1° or inferiorly at 62.1° to -1.0 mm at the lateral knee. The inferomedial GA branched from the PA at +9.9 mm. It traveled inferiorly at 21.2° to -33 mm at the medial knee. CONCLUSION: The GAs have a predictable pattern of location in the knee. There is a mismatch between medical textbooks and reality regarding arterial depictions. Knowledge regarding where the arteries are located may help reduce vascular complications in patients in the future.

Proximity of the Neurovascular Bundle During Posterior-Lateral Meniscal Repair: A Comparison of the Transpatellar, Anteromedial, and Anterolateral Portals.

PURPOSE: To compare the neurovascular proximity of the transpatellar portal with that of the medial and lateral portals and to determine the safe penetration depth for an all-inside device for use on the posterior horn lateral meniscus. METHODS: Dissection of the popliteal fossa was performed in 10 cadaveric knees to identify all structures. Arthroscopy was performed using penetration depths of 10, 12, 14, and 16 mm with the all-inside system through the anteromedial, anterolateral, and transpatellar portals. Penetrations were made 5 and 10 mm lateral to the posterior horn root at the meniscocapsular junction. Needle-tip distances were measured from the popliteal artery and vein, tibial nerve, and common peroneal nerve. RESULTS: Among 240 trials, the average distance to the popliteal neurovascular bundle using the medial, transpatellar, and lateral approaches was 6.9 mm, 6.5 mm, and 3.1 mm, respectively. The transpatellar-portal needle had a larger distance from the neurovascular bundle than the lateral portal (P = .001), with no statistical difference compared with the medial portal (P = .58). Compared with the position at a 10-mm distance from the root, the position at a 5-mm distance from the root was closer to the neurovascular bundle in all approaches (P = .001). The transpatellar approach set to 14 mm had a 5% rate of capsular underpenetration and 10% rate of gastrocnemius penetration. The transpatellar and medial portals had no neurovascular penetrations, whereas the lateral approach had a 14% rate of penetration (P < .05). CONCLUSIONS: The transpatellar portal and anteromedial portal are in less proximity to the neurovascular bundle compared with the anterolateral portal for all-inside meniscal repair of the posterior horn lateral meniscus. Low rates of neurovascular penetration, gastrocnemius muscle penetration, and capsular underpenetration occurred with a depth setting of 14 mm. CLINICAL RELEVANCE: This study shows the utility of medial and transpatellar portals when using all-inside devices to repair posterior horn lateral meniscal tears and neurovascular proximity based on penetration depth.

A comparative study comparing area of extension of posterior knee capsule via posteromedial injection: a cadaveric study.

BACKGROUND: Periarticular multimodal drug injection (PMDI) has gained popularity as common postoperative pain protocols in knee arthroplasty. PMDI sites can vary, but posterior capsule (PC) is a common injection site because of its abundance of pain nociceptors. PURPOSE: To prove the hypothesis whether posteromedial drug injection alone is sufficient to provide enough effect covering the PC in order to reduce risks of neurovascular injury. Secondary outcomes are to find proper volume of injection and safe zone for PMDI injection. METHODS: Ten fresh cadaveric knees were allocated into two equal groups, which differed in volume of dye injection: 25 ml and 50 ml. Dyes were injected into posteromedial capsule compartment, and the limbs were stored in a freezer for 2 weeks. Then the posterior compartment was carefully dissected to examine spreading of the dye solution. RESULTS: No dye staining was seen superficially beneath subcutaneous tissue of the knees. In deeper layer, the dye mostly occupied medially along the fascia covering semimembranosus muscles. However, dispersion was limited distally by intermuscular septa and popliteal vessels. The 50-ml injection group provided wider extension in the superficial layer, but not in the deep layer. CONCLUSION: The intermuscular septa and the fascia of popliteal vessels were shown to be the boundary between posteromedial and posterolateral compartments of the knee. Separate PMDI for both compartments is necessary to occupy the entire PC. We suggest that 1.5 cm lateral to lateral border of PCL insertion, just above popliteus tendon, is the safe zone for injecting PMDI into the posterolateral capsule.

Juvenile osteochondritis dissecans of the knee is a result of failure of the blood supply to growth cartilage and osteochondrosis.

OBJECTIVE: Juvenile osteochondritis dissecans (JOCD) is similar to osteochondrosis dissecans (OCD) in animals, which is the result of failure of the cartilage canal blood supply, ischemic chondronecrosis and delayed ossification, or osteochondrosis. The aim of the current study was to determine if osteochondrosis lesions occur at predilection sites for JOCD in children. METHOD: Computed tomographic (CT) scans of 23 knees (13 right, 10 left) from 13 children (9 male, 4 female; 1 month to 11 years old) were evaluated for lesions consisting of focal, sharply demarcated, uniformly hypodense defects in the ossification front. Histological validation was performed in 11 lesions from eight femurs. RESULTS: Thirty-two lesions consisting of focal, uniformly hypodense defects in the ossification front were identified in the CT scans of 14 human femurs (7 left, 7 right; male, 7-11 years old). Defects corresponded to areas of ischemic chondronecrosis in sections from all 11 histologically validated lesions. Intra-cartilaginous secondary responses comprising proliferation of adjacent chondrocytes and vessels were detected in six and two lesions, whereas intra-osseous responses including accumulation of chondroclasts and formation of granulation tissue occurred in 10 and six lesions, respectively. One CT cyst-like lesion contained both a pseudocyst and a true cyst in histological sections. CONCLUSION: Changes identical to osteochondrosis in animals were detected at predilection sites for JOCD in children, and confirmed to represent failure of the cartilage canal blood supply and ischemic chondronecrosis in histological sections.

Vascular Permeability and Remodelling Coincide with Inflammatory and Reparative Processes after Joint Bleeding in Factor VIII-Deficient Mice.

Vascular remodelling is a prominent feature of haemophilic arthropathy (HA) that may underlie re-bleeding, yet the nature of vascular changes and underlying mechanisms remain largely unknown. Here, we aimed to characterize synovial vascular remodelling and vessel integrity after haemarthrosis, as well as temporal changes in inflammatory and tissue-reparative pathways. Thirty acutely painful joints in patients with haemophilia (PWH) were imaged by musculoskeletal ultrasound with Power Doppler (MSKUS/PD) to detect vascular abnormalities and bloody effusions. Nineteen out of 30 painful joint episodes in PWH were associated with haemarthrosis, and abnormal vascular perfusion was unique to bleeding joints. A model of induced haemarthrosis in factor VIII (FVIII)-deficient mice was used for histological assessment of vascular remodelling (α-smooth muscle actin [αSMA] expression), and monitoring of in vivo vascular perfusion and permeability by MSKUS/PD and albumin extravasation, respectively. Inflammatory (M1) and reparative (M2) macrophage markers were quantified in murine synovium over a 10-week time course by real-time polymerase chain reaction. The abnormal vascular perfusion observed in PWH was recapitulated in FVIII-deficient mice after induced haemarthrosis. Neovascularization and increased vessel permeability were apparent 2 weeks post-bleed in FVIII-deficient mice, after a transient elevation of inflammatory macrophage M1 markers. These vascular changes subsided by week 4, while vascular remodelling, evidenced by architectural changes and pronounced αSMA expression, persisted alongside a reparative macrophage M2 response. In conclusion, haemarthrosis leads to transient inflammation coupled with neovascularization and associated vascular permeability, while subsequent tissue repair mechanisms coincide with vascular remodelling. Together, these vascular changes may promote re-bleeding and HA progression.

Surgical Treatment of Venous Malformations of the Knee: Treatment Outcomes for 35 Patients.

BACKGROUND: The place of open surgery in venous malformations (VMs) of knee joint is still discussed. The aim of this study was to evaluate the benefits of surgery in terms of pain, function, and quality of life. DESIGN: This was a retrospective observational study. METHODS: Thirty-five consecutive young patients undergoing surgery for VMs of the knee between 2011 and 2014 were included. Data collection was performed using a prospective database by reviewing patient records. Pain, mobility of the joint, residual VMs as seen by magnetic resonance imaging, and quality of life were the main outcome endpoints for this study. RESULTS: Thirty-five patients (22 females and 13 males, with a median age of 15 y, range of 5 to 20 y) were included. Twenty-seven VMs were localized in and around the knee joint, of which 8 were extensive. Indication for surgery was intermittent or permanent pain.Details of the surgical excisions of the VM are as follows: suprapatellar area in 57%, suprapatellar and infrapatellar area in 29%, infrapatellar area in 2%, limited in the femoropatellar area in 12%. Partial resection of a vastus muscle or patellar retinaculum was necessary for 19 patients.The median duration of the surgery was 4 hours (range: 2 to 7 h). The median hospital stay was 5 days; full-time physiotherapy was systematic for 2 to 3 weeks.After 6 months, 74% had no longer pain, the mobility of the joint was normal for 60%. Of the 33 patients who had a magnetic resonance imaging at 6 months, 86% (28 patients) had no residual intra-articular VMs, and 14% had focal residual VMs.At the last follow-up, 77% (27 patients) had no longer pain, 23% experienced intermittent pain with unusual activities, and 91% (32 patients) had normal mobility of the joint. Quality of life was increased significantly due to the pronounced impact on pain. CONCLUSION: Extensive surgical excision of knee VMs is a safe procedure with good outcomes in terms of pain, function, and quality of life. LEVEL OF EVIDENCE: Level II-retrospective observational monocentric study.