Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training.

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

Warming nondormant tree roots advances aboveground spring phenology in temperate trees.

Climate warming advances the onset of tree growth in spring, but above- and belowground phenology are not always synchronized. These differences in growth responses may result from differences in root and bud dormancy dynamics, but root dormancy is largely unexplored. We measured dormancy in roots and leaf buds of Fagus sylvatica and Populus nigra by quantifying the warming sum required to initiate above- and belowground growth in October, January and February. We furthermore carried out seven experiments, manipulating only the soil and not air temperature before or during tree leaf-out to evaluate the potential of warmer roots to influence budburst timing using seedlings and adult trees of F. sylvatica and seedlings of Betula pendula. Root dormancy was virtually absent in comparison with the much deeper winter bud dormancy. Roots were able to start growing immediately as soils were warmed during the winter. Interestingly, higher soil temperature advanced budburst across all experiments, with soil temperature possibly accounting for c. 44% of the effect of air temperature in advancing aboveground spring phenology per growing degree hour. Therefore, differences in root and bud dormancy dynamics, together with their interaction, likely explain the nonsynchronized above- and belowground plant growth responses to climate warming.

A robotic system for solo surgery in flexible ureteroscopy: development and evaluation with clinical users.

PURPOSE: The robotic system CoFlex for kidney stone removal via flexible ureteroscopy (fURS) by a single surgeon (solo surgery, abbreviated SSU) is introduced. It combines a versatile robotic arm and a commercially available ureteroscope to enable gravity compensation and safety functions like virtual walls. The haptic feedback from the operation site is comparable to manual fURS, as the surgeon actuates all ureteroscope DoF manually. METHODS: The system hardware and software as well as the design of an exploratory user study on the simulator model with non-medical participants and urology surgeons are described. For each user study task both objective measurements (e.g., completion time) and subjective user ratings of workload (using the NASA-TLX) and usability (using the System Usability Scale SUS) were obtained. RESULTS: CoFlex enabled SSU in fURS. The implemented setup procedure resulted in an average added setup time of 341.7 ± 71.6 s, a NASA-TLX value of 25.2 ± 13.3 and a SUS value of 82.9 ± 14.4. The ratio of inspected kidney calyces remained similar for robotic (93.68 %) and manual endoscope guidance (94.74 %), but the NASA-TLX values were higher (58.1 ± 16.0 vs. 48.9 ± 20.1) and the SUS values lower (51.5 ± 19.9 vs. 63.6 ± 15.3) in the robotic scenario. SSU in the fURS procedure increased the overall operation time from 1173.5 ± 355.7 s to 2131.0 ± 338.0 s, but reduced the number of required surgeons from two to one. CONCLUSIONS: The evaluation of CoFlex in a user study covering a complete fURS intervention confirmed the technical feasibility of the concept and its potential to reduce surgeon working time. Future development steps will enhance the system ergonomics, minimize the users' physical load while interacting with the robot and exploit the logged data from the user study to optimize the current fURS workflow.

MyD88 and not TRIF knockout is sufficient to abolish LPS-induced inflammatory responses in bone-derived macrophages.

Macrophages play an important role in the response to infection and/or repair of injury in tissues. To examine the NF-κB pathway in response to an inflammatory stimulus, we used wild-type bone-marrow-derived macrophages (BMDMs) or BMDMs with knockout (KO) of myeloid differentiation primary response 88 (MyD88) and/or Toll/interleukin-1 receptor domain-containing adapter-inducing interferon-ß (TRIF) via CRISPR/Cas9. Following treatment of BMDMs with lipopolysaccharide (LPS) to induce an inflammatory response, translational signalling of NF-κB was quantified via immunoblot and cytokines were measured. Our findings reveal that MyD88 KO, but not TRIF KO, decreased LPS-induced NF-κB signalling, and 10% expression of basal MyD88 expression was sufficient to partially rescue the abolished inflammatory cytokine secretion observed upon MyD88 KO.

The dose-response effects of arachidonic acid on primary human skeletal myoblasts and myotubes.

Background: Cellular inflammatory response, mediated by arachidonic acid (AA) and cyclooxygenase, is a highly regulated process that leads to the repair of damaged tissue. Recent studies on murine C2C12 cells have demonstrated that AA supplementation leads to myotube hypertrophy. However, AA has not been tested on primary human muscle cells. Therefore, the purpose of this study was to determine whether AA supplementation has similar effects on human muscle cells. Methods: Proliferating and differentiating human myoblasts were exposed to AA in a dose-dependent manner (50-0.80 µM) for 48 (myoblasts) or 72 (myotubes) hours. Cell viability was tested using a 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay and cell counting; myotube area was determined by immunocytochemistry and confocal microscopy; and anabolic signaling pathways were evaluated by western blot and RT-PCR. Results: Our data show that the treatment of primary human myoblasts treated with 50 µM and 25 µM of AA led to the release of PGE2 and PGF2α at levels higher than those of control-treated cells (p < 0.001 for all concentrations). Additionally, 50 µM and 25 µM of AA suppressed myoblast proliferation, myotube area, and myotube fusion. Anabolic signaling indicated reductions in total and phosphorylated TSC2, AKT, S6, and 4EBP1 in myoblasts at 50 µM of AA (p < 0.01 for all), but not in myotubes. These changes were not affected by COX-2 inhibition with celecoxib. Conclusion: Together, our data demonstrate that high concentrations of AA inhibit myoblast proliferation, myotube fusion, and myotube hypertrophy, thus revealing potential deleterious effects of AA on human skeletal muscle cell health and viability.

Celecoxib impairs primary human myoblast proliferation and differentiation independent of cyclooxygenase 2 inhibition.

The use of non-steroidal anti-inflammatory drugs (NSAIDs) for treatment of musculoskeletal injuries is commonplace in the general, athletic, and military populations. While NSAIDs have been studied in a variety of tissues, the effects of NSAIDs on skeletal muscle have not been fully defined. To address this, we investigated the degree to which the cyclooxygenase (COX)-2-selective NSAID celecoxib affects muscle cell proliferation, differentiation, anabolic signaling, and mitochondrial function in primary human skeletal myoblasts and myotubes. Primary muscle cells were treated with celecoxib or NS-398 (a pharmacological inhibitor of COX-2) as a control. Celecoxib administration significantly reduced myoblast proliferation, viability, fusion, and myotube area in a dose-dependent manner, whereas NS-398 had no effect on any of these outcomes. Celecoxib treatment was also associated with reduced phosphorylation of ribosomal protein S6 in myoblasts, and reduced phosphorylation of AKT, p70S6K, S6, and ERK in myotubes. In contrast, NS-398 did not alter phosphorylation of these molecules in myoblasts or myotubes. In myoblasts, celecoxib significantly reduced mitochondrial membrane potential and respiration, as evidenced by the decreased citric acid cycle (CAC) intermediates cis-aconitic acid, alpha-keto-glutarate acid, succinate acid, and malic acid. Similar results were observed in myotubes, although celecoxib also reduced pyruvic acid, citric acid, and fumaric acid. NS-398 did not affect CAC intermediates in myoblasts or myotubes. Together, these data reveal that celecoxib inhibits proliferation, differentiation, intracellular signaling, and mitochondrial function in primary human myoblasts and myotubes independent of its function as a COX-2 inhibitor.

Treatment of benign bone lesions with an injectable biphasic bone substitute.

BACKGROUND: Injectable biphasic ceramic bone substitutes (BCBSs) represent a modern alternative to conventional options for bone defect filling, as they further open the possibilities for percutaneous cavity reconstruction. Although recent studies have shown good surgical outcomes after treatment with BCBSs, mid-term follow-up data are still missing. PATIENTS AND METHODS: Between 2013 and 2017, 18 patients were [1] treated with BCBS [2] for benign bone lesions and [3] had a complete set of retrospective information, including surgical protocols, imaging, patient dismission letters and outpatient clinic protocols, [4] with a minimum follow-up time of one year. Eleven patients received percutaneous surgery, while 7 patients had open curettage and BCBS filling. The median follow-up time was 36.5 (range 12-80) months. RESULTS: Local recurrence was reported in four patients. A distinctive bone remodelling pattern was noted on follow-up X-ray and magnetic resonance imaging showing a double-line phenomenon and continuously increasing cortical thickness one year after treatment in nine of thirteen patients. Regarding surgical complications, one patient suffered from a septic complication that required BCBS removal and lavage. One patient experienced superficial surgical site inflammation with redness and swelling, while two other patients had prolonged wound secretion. CONCLUSION: In a limited case series, the studied BCBS demonstrated acceptable surgical outcomes. Initial wound leakage and recurrence seemed to be associated with percutaneous injection. Further studies are needed to compare recurrence and bone graft resorption after open and percutaneous bone cyst surgeries and to further evaluate postoperative surgical site inflammation, which appears self-limiting in most cases.

[Epiphysiodesis and hemiepiphysiodesis : Physeal arrest and guided growth for the lower extremity]. / Epiphysiodesen und Hemiepiphysiodesen : Wachstumsstopp und Wachstumslenkung an der unteren Extremität.

The principals of growth arrest by epiphysiodesis and growth guidance by hemiepiphysiodesis are effective and powerful surgical techniques in pediatric orthopedics. These procedures can be used to correct leg length discrepancies as well as sagittal, coronal and oblique deformities. A differentiation is made between temporary and permanent techniques. The most significant advantage is that these techniques are minimally invasive and have low complication rates compared to acute osteotomy and gradual deformity correction. For optimal outcome an exact preoperative planning is needed to ensure accurate timing of the procedure, especially when permanent epiphysiodesis techniques are used. Although epiphysiodesis and hemiepiphysiodesis around the pediatric knee are most frequently used and can be considered the gold standard treatment of coronal plane deformities and leg length discrepancies, novel techniques for the hip and ankle are increasingly being performed. The successful clinical results with low complications support the broad use of hemiepiphysiodesis and epiphysiodesis for a variety of indications in the growing skeleton with deformities and leg length differences.

Comparison of CRISPR and adenovirus-mediated Myd88 knockdown in RAW 264.7 cells and responses to lipopolysaccharide stimulation.

Genomic manipulation offers the possibility for novel therapies in lieu of medical interventions in use today. The ability to genetically restore missing inflammatory genes will have a monumental impact on our current immunotherapy treatments. This study compared the efficacy of two different genetic manipulation techniques: clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) transfection to adenoviral transduction to determine which method would provide the most transient and stable knockdown of myeloid differentiation primary response 88 (MyD88). MyD88 is a major regulator of nuclear factor kappa light chain enhancer of activated B cells (NFκB) pathway in Raw 264.7 macrophages. Following genetic manipulation, cells were treated for 24 h with Lipopolysaccharide (LPS) to stimulate the inflammatory pathway. Confirmation of knockdown was determined by western immunoblotting and quantification of band density. Both CRISPR/Cas9 and adenoviral transduction produced similar knockdown efficiency (~64% and 60%, respectively) in MyD88 protein 48 h post adenoviral transduction. NFκB phosphorylation was increased in CRISPR/Cas9-mediated MyD88 knockdown and control cells, but not in adenovirus-mediated MyD88 knockdown cells, following LPS administration. CRISPR/Cas9-mediated MyD88 knockdown macrophages treated with LPS for 24 h showed a 65% reduction in tumor necrosis factor alpha (TNFα) secretion, and a 67% reduction in interleukin-10 (IL-10) secretion when compared to LPS-stimulated control cells (P ≤ 0.01 for both). LPS did not stimulate TNFα or IL-10 secretion in adenovirus-mediated control or MyD88 knockdown cells. These data demonstrate that Raw 264.7 macrophages maintain responsiveness to inflammatory stimuli following CRISPR/Cas9-mediated reductions in MyD88, but not following adenovirus-mediated MyD88 knockdown.

Epiphysiodesis for the treatment of tall stature and leg length discrepancy.

Painful orthopedic conditions associated with extreme tall stature and leg length discrepancy (LLD) include back pain and adopting bad posture. After failure of conservative treatment options, blocking of the growth plates (epiphysiodesis) around the knee emerged as gold standard in patients with tall stature and LLD in the growing skeleton. Surgical planning includes growth prediction and evaluation of bone age. Since growth prediction is associated with a certain potential error, adequate planning and timing of epiphysiodesis are the key for success of the treatment. LLD corrections up to 5 cm can be achieved, and predicted extreme tall stature can be limited. Percutaneous epiphysiodesis techniques are minimally invasive, safe and efficient methods with low complication rates. In general, a multidisciplinary approach should be pursued when treating children and adolescents with tall stature.

Emerging evidence that adaptive bone formation inhibition by non-steroidal anti-inflammatory drugs increases stress fracture risk.

There is mounting evidence suggesting that the commonly used analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), may inhibit new bone formation with physical training and increase risk of stress fractures in physically active populations. Stress fractures are thought to occur when bones are subjected to repetitive mechanical loading, which can lead to a cycle of tissue microdamage, repair, and continued mechanical loading until fracture. Adaptive bone formation, particularly on the periosteal surface of long bones, is a concurrent adaptive response of bone to heightened mechanical loading that can improve the fatigue resistance of the skeletal structure, and therefore may play a critical role in offsetting the risk of stress fracture. Reports from animal studies suggest that NSAID administration may suppress this important adaptive response to mechanical loading. These observations have implications for populations such as endurance athletes and military recruits who are at risk of stress fracture and whose use of NSAIDs is widespread. However, results from human trials evaluating exercise and bone adaptation with NSAID consumption have been less conclusive. In this review, we identify knowledge gaps that must be addressed to further support NSAID-related guidelines intended for at-risk populations and individuals.

Development of an electronic navigation system for elimination of examiner-dependent factors in the ultrasound screening for developmental dysplasia of the hip in newborns.

To develop an electronic navigation system to increase reliability and comparability in the ultrasound screening of developmental dysplasia of the hip (DDH). The impact of the navigation system on transducer positioning and on sonographic measurements according to Graf was analyzed. Twenty hips in newborns were examined sonographically using a new navigation system capable of detecting the transducer and pelvis position in order to calculate the relative tilt in the frontal, axial, and sagittal-plane. In each newborn an ultrasound image was obtained conventionally according to Graf and a second image using the sonographic navigation system. Relative roll and pitch angles and sonographic measurements were analyzed using paired T-tests and Levene-tests. Relative tilt angles in the conventional group ranged from - 8.9° to 14.3° (frontal-plane) and - 23.8° to 14.2° (axial-plane). In the navigation-assisted group ranges from - 3.0° to 3.5° and - 2.8° to 4.5° were observed. Variances were significantly lower in the navigation-assisted group (p < 0.001 and p = 0.004 respectively). The navigation system allowed for a significant reduction of relative tilt angles between the transducer and the newborn pelvis, thus supporting an optimal transducer positioning. This is a promising approach to improve reproducibility and reliability in the ultrasound screening for DDH.

Recombinant Human BMP6 Applied Within Autologous Blood Coagulum Accelerates Bone Healing: Randomized Controlled Trial in High Tibial Osteotomy Patients.

Bone morphogenetic proteins (BMPs) are potent osteogenic proteins that induce new bone formation in vivo. However, their effect on bone healing in the trabecular bone surfaces remains challenging. We evaluated the safety and efficacy of recombinant human BMP6 (rhBMP6) applied within an autologous blood coagulum (ABC) in a surgically created wedge defect of the proximal tibia in patients undergoing high tibial osteotomy (HTO) for varus deformity and medial osteoarthritis of the knee. We enrolled 20 HTO patients in a randomized, placebo-controlled, double-blinded phase I/II clinical trial. RhBMP6/ABC (1.0 mg/10 mL ABC prepared from peripheral blood) or placebo (10 mL ABC containing excipients) was administered into the tibial wedge defects. Patients were followed for 0 to 24 months by clinical examination (safety) and computed tomography (CT) and serial radiographic analyses (efficacy). The results show that there were no detectable anti-rhBMP6 antibodies in the blood of any of the 20 patients at 14 weeks after implantation. During the 24 months of follow-up, there were no serious adverse reactions recorded. The CT scans from defects of patients treated with rhBMP6/ABC showed an accelerated bone healing compared with placebo at 9 weeks (47.8 ± 24.1 versus 22.2 ± 12.3 mg/cm3 ; p = 0.008) and at 14 weeks (89.7 ± 29.1 versus 53.6 ± 21.9 mg/cm3 ; p = 0.006) follow-up. Radiographic analyses at weeks 6 and 24 and months 12 and 24 suggested the advanced bone formation and remodeling in rhBMP6/ABC-treated patients. In conclusion, we show that rhBMP6/ABC at a dose of 100 µg/mL accelerated bone healing in patients undergoing HTO without serious adverse events and with a good tolerability compared with placebo alone. Overall, for the first time, a BMP-based osteogenic implant was examined against a placebo for bone healing efficacy in the trabecular bone surface, using an objective bone mineral density measurement system. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Radiographic Sagittal Tibio-Talar Offset in Ankle Arthrodesis-Accuracy and Reliability of Measurements.

Radiographic outcome assessment of ankle arthrodesis (AA) requires accurate measurement techniques. This study aimed to identify the most reliable methods for sagittal tibio-talar alignment measurements with regard to the tibio-talar offset after AA. Lateral weight-bearing radiographs of 38 fused ankles were selected for retrospective review. The sagittal tibio-talar angle (STTA), the modified tibio-talar ratio (mT-T ratio) and the sagittal tibio-talar offset (tibCOR, procLAT) were measured by three independent observers. Intra- and interobserver correlation coefficients (ICC) and mean measurement differences were calculated to assess measurement reliability and accuracy. By defining the talar longitudinal axis as a line from the inferior aspect of the posterior tubercle of the talus to the most inferior aspect of the talar neck, STTA showed excellent (ICC 0.924; CI 95% 0.862-0.959) and mTT-ratio provided high (ICC 0.836; CI 95% 0.721-0.909) interobserver reliability, respectively. For tibio-talar offset measurement the tibCOR method showed superior reliability and better interobserver agreement compared to the procLAT technique. The STTA and a modified T-T ratio are recommended for future scientific radiographic measurements in AA.

Sports activity after soft tissue sarcoma of the lower extremity.

Introduction: The aim of this case series was to assess sports activity levels in long-term survivors of soft-tissue sarcomas after multimodal treatment including limb salvaging surgical resection and radio-chemotherapy.Methods: Thirty-two patients (17 f/15 m) with a mean age of 29 (range 10-44) years at the time of diagnosis and a mean follow-up time of 9 (range 3-21) years following sarcoma were included. Ten patients had been diagnosed with liposarcoma, seven with synovial sarcoma, four with fibrosarcoma, three with undifferentiated pleomorphic sarcomas and the remaining eight patients with different soft-tissue sarcoma entities. Sarcoma location of twenty-four (75%) patients was in the thigh, eight (25%) in the lower leg. Eleven (34%) tumors were located epifascial, 21 (66%) in deeper tissue layers. Sports activity was measured by the University of California, Los Angeles (UCLA) Activity Score.Results: One year before treatment 30 patients (94%) and >3 years post-treatment 29 patients (91%)had been pursuing athletic activity regularly. They were performing 5.5 h/week prior and 4.2 h/week >3 years post surgery. The mean UCLA score in case of subfascial sarcomas was 8.0 and thereby lower (p < 0.05) than those of epifascial sarcomas, which were 9.3. Furthermore, the mean UCLA score after subfascial sarcoma resection 3 years postoperative was still below preoperative UCLA levels (p < 0.05), whereas patients after epifascial tumor resection showed no loss of sports activity. No relation between complications and postoperative sports activity level was found.Conclusions: Healthy long-term survivors can achieve high levels of sports activity following limb salvage after soft-tissue sarcomas. The concerned muscle groups may influence the functional and sports outcome and draw attention to this topic in future rehabilitation. This knowledge may be of high value for patients counseling, physicians and orthopedists treating patients, as well as for patients inquiring information regarding post-treatment activity levels.Implication for rehabilitationSport is possible after soft tissue sarcoma treatment and longer-term rehabilitation which is usually three yearsRehabilitation is best undertaken in specialized centersIt is important to maintain contact with surgeons in order to optimize mobilizationHigh impact sports may be affected by deep muscle resections.

Evaluation of Aerosol Electrospray Analysis of Metal-on-Metal Wear Particles from Simulated Total Joint Replacement.

Wear is a common cause for aseptic loosening in artificial joints. The purpose of this study was to develop an automated diagnostical method for identification of the number and size distribution of wear debris. For this purpose, metal debris samples were extracted from a hip simulator and then analyzed by the electrospray method combined with a differential mobility analyzer, allowing particle detection ranging from several nanometers up to 1 µm. Wear particles were identified with a characteristic peak at 15 nm. The electrospray setup was successfully used and validated for the first time to characterize wear debris from simulated total joint replacement. The advantages of this diagnostic method are its time- and financial efficiency and its suitability for testing of different materials.

Analysis and quantification of bone healing after open wedge high tibial osteotomy.

BACKGROUND: The aim of this study was to analyze radiographic imaging techniques and to quantify bone ossification in the osteotomy gap after high tibial osteotomy. MATERIAL AND METHODS: Study phase 1: high tibial osteotomy was performed on six lower extremities of human body donors and experimental X­rays and computed tomography (CT) scans were applied. Different techniques were evaluated by three specialists for best representation of the osteotomy gap. Study phase 2: optimized radiological techniques were used for follow-up on 12 patients. The radiographs were examined by 3 specialists measuring 10 different parameters. The CT scans were analyzed with semiautomatic computer software for quantification of bone ossification. RESULTS: The osteotomy gap was best represented in 30° of flexion in the knee and 20° internal rotation of the leg. There were significant changes of the medial width over time (p < 0.019) as well as of the length of fused osteotomy, the Schröter score, sclerosis, trabecular structure and zone area measurements. Sclerosis, medial width of the osteotomy and area measurements were detected as reproducible parameters. Bone mineral density was calculated using CT scans, showing a significantly higher value 12 weeks postoperatively (112.5 mg/cm3) than at baseline (54.6 mg/cm3). The ossification of the gap was visualized by color coding. CONCLUSION: Sclerosis and medial width of the osteotomy gap as well as area measurements were determined as reproducible parameters for evaluation of bone healing. Quantification of bone ossification can be calculated with CT scans using a semiautomatic computer program and should be used for research in bone healing.

The role of the subchondral layer in osteonecrosis of the femoral head: analysis based on HR-QCT in comparison to MRI findings.

BACKGROUND: Non-traumatic avascular osteonecrosis of the femoral head (ONFH) is a severe disease causing destruction of the hip joint, often necessitating total hip arthroplasty (THA) even in young patients. Magnetic resonance imaging (MRI) is commonly used for diagnosis of ONFH, but provides limited insight into the subchondral bone microstructure. PURPOSE: To analyze routine MRI findings in comparison to high-resolution quantitative computed tomography (HR-QCT) with a special focus on the subchondral layer and to estimate the importance of differences determining the indication for THA. MATERIAL AND METHODS: Twelve patients with ONFH were included before THA. Preoperative MRI and HR-QCT of the retrieved femoral heads were aligned using a registration algorithm. Pathological findings and trabecular bone parameters in matched areas were analyzed by two readers. McNemar, marginal homogeneity test, and Pearson's correlation coefficient were used for comparison. RESULTS: Subchondral delamination was found in nine cases on HR-QCT, but missed or underestimated in all but one case on MRI ( P = 0.016). Chondral discontinuity was found in all cases on HR-QCT and in two cases on MRI ( P = 0.016). Areas of complete bone resorption on HR-QCT were linked to high signal intensity on 3D gradient-echo MRI sequences with water-selective excitation, while there was no correlation between trabecular bone parameters and MRI signal intensities in other areas ( P = 0.304). CONCLUSION: Subchondral delamination, subchondral resorption, and chondral discontinuity are found frequently in advanced stages of ONFH. These lesions tend to be underestimated on conventional MRI. Our results support the importance of CT imaging in the evaluation of ONFH.

Distal femoral varus osteotomy: results of the lateral open-wedge technique without bone grafting.

BACKGROUND: The lateral opening wedge distal femoral osteotomy (LOWDFO) to reconstruct knee alignment in patients with genu valgum originating in the distal femur has gained importance within the last years. PURPOSE: To analyze clinical and radiographic outcome of patients treated with LOWDFO with respect to bone healing without grafting and patient age. MATERIAL AND METHODS: Twenty-two consecutive patients with genu valgum corrected with 23 LOWDFOs using a Tomofix-locking plate were retrospectively analyzed (mean age 23.7 years). Clinical evaluation was based on pre- and post-operative KOOS scores. A pre- and post-operative radiographic assessment, including MAD, mLDFA, LLD, bone healing, and patella parameters, was performed. Differences between subgroups (age, bone grafting) were analyzed. RESULTS: The restoration of MAD and mLDFA resulted in significantly improved post-operative KOOS5 scores in younger and older patients (p = 0.001). Bone healing without bone grafting was reliable in all patients. The leg length was significantly increased post-operatively (p = 0.001). The Blackburne-Peel ratio was significantly reduced to more normal values post-operatively (p < 0.001). CONCLUSION: LOWDFO without bone grafting is a reliable procedure representing a promising treatment option particularly in young patients with genu valgum. Besides correction of the MAD, a significant leg length increase and additional patella stability can be expected.