Anteroposterior Knee Radiographs Research Articles

Prevalence and distribution of the fabella: a radiographic study in Turkish subjects.

The purpose of this study is to examine the plain knee radiographs in Turkish subjects in order to determine the prevalence of the fabella and analyse the differences between age, gender, laterality and its symmetry pattern. Bilateral antero-posterior and lateral knee radiographs of 500 patients (250 male and 250 female subjects, 1000 knee radiographs) were randomly selected from the clinical database and retrospectively evaluated. Data on patient age, gender, and knee laterality (right-left) were evaluated from hospital records. The differences between the sesamoid bones at a particular location and the side, sex and age groups were analysed. The overall prevalence of the fabella (unilateral or bilateral) was 22.8% (114 subjects). The fabella was present unilaterally in 38 (7.6%) subjects, while it was present bilaterally in 76 (15.2%) subjects. The prevalence of the fabella was similar between the body sides. The prevalence of the fabella was also similar between genders (unilateral or bilateral cases) and age groups. We examined the prevalence, symmetry pattern, age and gender differences in Turkish population. It is the first study performed on Turkish population with the largest sample in current literature. Prevalence of fabella is found to be 22.8% which is quite similar with other Caucasian ethnic populations.

Radiographic Findings in Patients With Catastrophic Varus Collapse After Total Knee Arthroplasty

BackgroundCatastrophic varus collapse is an uncommon mechanism of failure in primary total knee arthroplasty (TKA). Varus collapse has been associated with obesity and smaller implant sizes. However, to our knowledge, preoperative radiographic characterization of this cohort has not been performed. Therefore, the following study evaluated preoperative alignment and how this correlates with the degree of eventual varus collapse identified in this patient population prior to revision. MethodsUtilizing our institutional database, 1106 revision TKAs were performed from 2004 to 2017. Of these, 35 patients were revised secondary to tibial varus collapse. Twenty-seven patients had their primary TKA performed at our institution. Coronal alignment of the knee was recorded from anteroposterior knee radiographs. Medial tibial bone loss was recorded at final follow-up. ResultsThe average body mass index was 38 kg/m2. Twenty-six of 27 patients had a preoperative varus deformity (4.2° varus) and all were corrected to a valgus coronal alignment immediately postoperatively (5.2° valgus, P = .0001). Twenty-four of 27 patients' coronal alignment after varus collapse was within 2° of their preoperative alignment (5.8° varus). Twenty-five of 27 patients had radiographic medial tibial bone loss prior to varus collapse. ConclusionTibial varus collapse in an uncommon cause of failure after primary TKA. Preoperative varus deformity, postoperative medial tibial bone loss, and obesity were common findings in this series of patients. Therefore, increased tibial stem lengths should be considered in patients with a preoperative varus deformity, small tibial implant size, and a body mass index ≥35 kg/m2 undergoing primary TKA.

Serum levels of the bone turnover markers dickkopf-1, osteoprotegerin, and TNF-α in knee osteoarthritis patients.

Knee osteoarthritis (KOA) is a common degenerative joint disease causing pain, stiffness, reduced motion, swelling, crepitus, and disability. Several inflammatory markers and cartilage degradation products can be used as biomarkers in OA. The key factors of bone metabolism in normal joint bone, dickkopf-1 (DKK1) and osteoprotegerin (OPG), interact with Wnt signaling pathway, balancing between bone absorption and bone reconstruction. TNF-α is a key inducer of DKK-1, which belongs to the family of proteins involved in joint remodeling. The present study compared the serum levels of DKK1, TNF-α, and OPG in patients with KOA and healthy controls to analyze the interrelationship and the severity of joint destruction. One hundred forty-eight patients with KOA and 101 healthy controls were enrolled in this study. Anteroposterior knee radiographs determined the severity of the disease in the affected knee. The radiographic grading of KOA was performed by the Kellgren-Lawrence criteria. Serum levels of DKK-1, TNF-α, and OPG were estimated using the multiplex particle-based flow cytometry. Higher serum levels of OPG and TNF-α were observed in KOA than the controls; KOA patients showed a lower serum level of DKK-1, whereas the serum levels of DKK1 correlated with the progression of KOA. The serum levels of TNF-α, OPG, and DKK-1 correlated with incident KOA. In the ROC curve analysis, DKK1 levels showed 78.6% sensitivity and 40% specificity, TNF-α levels showed 74.1% sensitivity and 76.0% specificity, and OPG showed 88.1% sensitivity and 81% specificity in predicting severe KOA. In the univariate and multivariate analyses, TNF-α and OPG emerged as independent predictors of severe KOA. This study, for the first time, combined TNF-α, DKK1, and OPG as valuable biological markers in predicting the severity of KOA radiographically in the clinic. This study also supported the inflammation-induced DKK1 and OPG in OA pathogenesis.

Associations between obesity and the radiographic phenotype in knee osteoarthritis.

Investigation of the association between obesity and the distinction of radiographic patterns in knee osteoarthritis. Seven hundred and thirty-four women underwent weight-bearing antero-posterior knee radiography. Osteophytes and joint space narrowing (JSN) were graded according to the OARSI atlas. Each subject was assigned to one of the following groups with respect to the maximum score: osteophyte-dominant, indeterminate, JSN-dominant, and radiographically normal. Obese patients had a significantly more frequent osteophyte-dominant pattern compared to nonobese subjects (74.5% and 38%, respectively, P < 0.001). Logistic regression analysis demonstrated that obesity had a stronger association with an osteophyte-dominant pattern compared to a JSN-dominant pattern (OR and 95% CI = 7.16 (3.15-16.26) and 1.63 (0.96-2.78), respectively). Age had a very weak effect on the distinction to an osteophyte-dominant pattern and no effect on JSN dominance (OR and 95% CI = 1.1 (1.06-1.15) and 1.02 (0.99-1.05), respectively). There might be an association between obesity and the radiographic phenotype in patients with knee osteoarthritis. The findings suggest that the association between obesity and the osteophyte formation is stronger than that of JSN.

Expression of hypoxia-inducible factor-1α in synovial fluid and articular cartilage is associated with disease severity in knee osteoarthritis.

The aim of the present study was to examine hypoxia-inducible factor 1α (HIF-1α) levels in the synovial fluid and articular cartilage of patients with primary knee osteoarthritis (OA) and to investigate their association with the severity of disease. A total of 36 patients with knee OA and ten healthy controls were enrolled. Anteroposterior knee radiographs and/or Mankin scores were assessed to determine the disease severity of the affected knee. Radiographic grading of OA in the knee was performed according to Kellgren-Lawrence criteria. HIF-1α levels in synovial fluid were measured using enzyme-linked immunosorbent assay, whereas HIF-1α levels in articular cartilage were assessed with immunohistochemical methods. Compared with healthy controls, OA patients exhibited an increased HIF-1α concentration in synovial fluid (218.17±25.12 vs. 156.66±7.74 pg/ml; P<0.001) and articular cartilage (P<0.05). Furthermore, synovial fluid HIF-1α levels demonstrated a positive correlation with articular cartilage HIF-1α levels (Pearson's P=0.815; P<0.001). Subsequent analysis showed that synovial fluid HIF-1α levels were significantly correlated with the severity of disease (Spearman's ρ=0.933; P<0.001). Furthermore, articular cartilage levels of HIF-1α also correlated with disease severity (Spearman's ρ=−0.967; P<0.001). The findings of the present study suggested that HIF-1α in synovial fluid and articular cartilage is associated with progressive joint damage and is likely to be a useful biomarker for determining disease severity and progression in knee OA.

Objective Metric of Energy Absorbed in Tibial Plateau Fractures Corresponds Well to Clinician Assessment of Fracture Severity.

Determine the agreement between subjective assessments of fracture severity and an objective computed tomography (CT)-based metric of fracture energy in tibial plateau fractures. Six fellowship-trained orthopaedic trauma surgeons independently rank-ordered 20 tibial plateau fractures in terms of severity based on anteroposterior and lateral knee radiographs. A CT-based image analysis methodology was used to quantify the fracture energy, and agreement between the surgeons' severity rankings and the fracture energy metric was tested by computing their concordance, a statistical measure that estimates the probability that any 2 cases would be ranked with the same ordering by 2 different raters or methods. Concordance between the 6 orthopaedic surgeons ranged from 82% to 93%, and concordance between surgeon severity rankings and the computed fracture energy ranged from 73% to 78%. There is a high level of agreement between experienced surgeons in their assessments of tibial plateau fracture severity, and a slightly lower agreement between the surgeon assessments and an objective CT-based metric of fracture energy. Taken together, these results suggest that experienced surgeons share a similar understanding of what makes a tibial plateau fracture more or less severe, and an objective CT-based metric of fracture energy captures much but not all of that information. Further research is ongoing to characterize the relationship between surgeon assessments of severity, fracture energy, and the eventual clinical outcomes for patients with fractures of the tibial plateau.

Can the frontal tibiofemoral alignment be assessed on anteroposterior knee radiographs?

BackgroundThe aim of total knee arthroplasty is, amongst others, the reconstruction of a physiological axis of the leg with a tibiofemoral angle in the frontal plane of an average of 6°. The aim of this study is to clarify how much of the bone length on the femur and tibia has to be reproduced on anteroposterior (AP) knee radiographs in order to determine the leg’s alignment after a total knee arthroplasty.Materials and methodsWe analyzed the postoperative hip-to-ankle (HTA) radiographs of 100 patients who had undergone a total knee arthroplasty at our institution.ResultsThere were strong correlations between the measured values on HTA and 20 cm bone length [lateral distal femur angle (LDFA) r = 0.887, medial proximal tibial angle (MPTA) r = 0.874, tibiofemoral angle (TFA) r = 0.888], but not between the measurements on HTA and 10 cm (LDFA r = 0.267, MPTA r = 0.102, TFA r = 0.161). There were significant differences between all measurements both on HTA and 20 cm and on HTA and 10 cm, with the exception of the LDFA between HTA and 10 cm (p = 0.085) and of the MPTA between HTA and 20 cm (p = 0.227). The intra- and inter-observer correlations were both high.ConclusionIf preoperatively crude axis deviations are excluded, the tibiofemoral angle on AP knee radiographs can be determined with an accuracy of ±2.6° if at least 20 cm length of bone is reproduced (measured from the femoral and tibial joint line). Due to the high 95 % confidence intervals and bearing in mind that deviations greater than 3° may lead to inferior clinical results, however, it appears inappropriate to determine lower limb alignment with anteroposterior radiographs.Level of evidenceLevel 2.

The influence of graft placement on clinical outcome in anterior cruciate ligament reconstruction.

the aim of the present study was to investigate the influence of graft tunnel position on both clinical outcome and instrumental knee stability in patients submitted to arthroscopic ACL reconstruction using a bone-patellar tendon-bone (BPTB) graft. thirty patients (24 men and 6 women) who underwent ACL reconstruction performed using an autologous bone-patellar tendon-bone graft were studied at a mean follow-up of 18 months. Clinical outcome was assessed on the basis of the Lysholm score, Tegner activity level, International Knee Documentation Committee (IKDC) subjective form and the Short Form-36. Clinical outcomes were correlated with both femoral and tibial tunnel placement measured on standard anteroposterior and lateral knee radiographs, in accordance with established guidelines. tibial tunnel position on the lateral view correlated significantly with both the IKDC subjective form (r = -0.72; p<0.05) and the Lysholm score (r=-0.73; p<0.05). Tibial tunnel position on the lateral view also correlated with stability measured using a KT-1000 arthrometer at 30N of force (r=0.57; p<0.05). No correlation was found between α angle and anteroposterior (AP) laxity measured by KT-1000 arthrometer. No significant correlation was found between femoral tunnel position (on either view) and Lysholm score, IKDC score and Tegner activity level. Similarly, no correlation was found between AP laxity measured by KT-1000 arthrometer and femoral tunnel position. these results suggest that the more anterior the placement of the tibial tunnel, the better the clinical outcome will be. On the basis of literature data and our findings, we discuss the hypothesis that there exists a "correct area" for tunnel placement, making it possible to obtain the best results. Level IV, case series.

Risk factors for noncontact anterior cruciate ligament injury: Analysis of parameters in proximal tibia using anteroposterior radiography.

ObjectiveTo investigate the relationship between the proximal tibial parameters of tibia width (TW), eminence width (EW), and eminence width index (EWI), and noncontact anterior cruciate ligament (ACL) injury, in a Chinese population.MethodsA retrospective case–control study was conducted of all ACL reconstructions (ACL group) and meniscal surgeries (control group) undertaken at two Chinese hospitals. Patients in the ACL group were age- and sex-matched with controls. Anteroposterior knee radiographs were used to measure the TW, EW and EWI.ResultsA total of 73 pairs of patients who were verified by knee arthroscopy, magnetic resonance imaging and physical examination were included in the study. There was no significant difference between the ACL group and the control group in terms of TW in the total population and in the two sex subgroups. The ACL group had a significantly smaller EW and EWI compared with the control group in the total population and in the two sex subgroups.ConclusionDecreased EW and EWI are associated with increased risk of noncontact ACL injury in a Chinese population.

Plasma and Synovial Fluid CXCL12 Levels Are Correlated With Disease Severity in Patients With Knee Osteoarthritis

BackgroundThe aim is to determine whether CXC chemokine ligand–12 (CXCL12) levels in plasma and synovial fluid (SF) of patients with knee osteoarthritis (OA) are correlated with the disease severity. In addition, we set out to investigate whether a peripheral blood test can avoid aspirating patients to determine CXCL12 levels. MethodsThis study consisted of 244 patients with knee OA and 244 age- and gender-matched healthy controls. Osteoarthritis progression was classified based on Kellgren-Lawrence (KL) by evaluating radiographic changes observed in anteroposterior knee radiography. The CXCL12 levels in the plasma and SF were measured by a quantitative sandwich enzyme-linked immunosorbent assay. ResultsPlasma CXCL12 levels were higher in OA patients as compared with controls (P < .0001). There was a positive correlation between levels of CXCL12 and grade (P < .0001). Base on the receiver operating characteristic curve, the optimal cutoff value of plasma CXCL12 levels as an indicator for screening of OA was estimated to be 5.5 ng/mL, which yielded a sensitivity of 78.4% and a specificity of 80.2%, with the area under the curve at 0.850 (95% confidence interval [CI], 0.816-0.889; P < .0001). In multivariate analysis, there was an increased risk of active OA associated with plasma CXCL12 levels ≥10.5 ng/mL (odds ratio, 6.76; 95% CI, 3.88–12.53; P < .0001) after adjusting for possible confounders. Similarly, there was an increased risk of active OA associated with SF CXCL12 levels ≥15.0 ng/mL (odds ratio, 8.45; 95% CI, 3.23-18.22; P < .0001) after adjusting for possible confounders. ConclusionThe CXCL12 levels in the plasma and SF may serve as effective biomarkers for the severity of OA.

Are Standard Post-Operative Anteroposterior and Lateral Knee Radiographs Predictive of Anatomic Femoral Tunnel Placement in ACL Reconstruction?

Are Standard Post-Operative Anteroposterior and Lateral Knee Radiographs Predictive of Anatomic Femoral Tunnel Placement in ACL Reconstruction?

Correlation of bone morphogenetic protein-2 levels in serum and synovial fluid with disease severity of knee osteoarthritis.

BackgroundThis study aimed to investigate the bone morphogenetic protein-2 (BMP-2) levels in serum and synovial fluid (SF) of patients with primary knee osteoarthritis (OA) and to exam its correlation with radiographic and symptomatic severity of the disease.Material/MethodsA total of 37 knee OA patients and 20 healthy controls were enrolled in this study. Knee OA radiographic grading was performed according to the Kellgren-Lawrence (KL) grading system by evaluating X-ray changes observed in anteroposterior knee radiography. Symptomatic severity of the disease was evaluated according to the Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores. BMP-2 levels in serum and SF were determined using enzyme-linked immunosorbent assay.ResultsSerum BMP-2 level in patients with knee OA was higher than that in healthy controls. Knee OA patients with KL grade 4 showed significantly elevated BMP-2 levels in the serum and SF compared with those with KL grade 2 and 3. Knee OA patients with KL grade 3 had significant higher SF levels of BMP-2 than those with KL grade 2. BMP-2 levels in the serum and SF of knee OA patients were both positively correlated with KL grades and WOMAC scores.ConclusionsBMP2 levels in serum and SF were closely related to the radiographic and symptomatic severity of knee OA and may serve as an alternative biochemical parameter to determine disease severity of primary knee OA.

Hip–Knee–Ankle Radiographs Are More Appropriate for Assessment of Post-Operative Mechanical Alignment of Total Knee Arthroplasties than Standard AP Knee Radiographs

Weight-bearing hip–knee–ankle (HKA) radiographs are the gold standard for measuring lower limb alignment after total knee arthroplasty (TKA), however the majority of UK units use standardised anteroposterior (AP) knee radiographs. This study aimed to determine whether standardised AP knee radiographs adequately assess lower limb alignment after TKA. HKA radiographs from 50 post-operative TKAs were cropped to the size of a standardised AP knee radiograph allowing comparison of mechanical and anatomical alignment measurements between the two views. Repeatability of alignment measurements was significantly better for HKA radiographs, however, there was poor agreement of the mechanical alignment measured between the two views. Standardised AP knee radiographs are insufficient to assess the mechanical alignment of post-operative TKA and we recommend routinely using HKA radiographs.

Transphyseal Anterior Cruciate Ligament Reconstruction in Patients With Open Physes

Background: The treatment of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial. Current evidence supports the view that surgical techniques restore knee stability and prevent progressive articular damage. However, most of the studies on this topic are small case series or they have short- or medium-term follow-up times. Purpose: To determine the long-term functional outcomes and secondary complications of transphyseal intra-articular ACL reconstruction with hamstring graft in skeletally immature patients. Study Design: Case series; Level of evidence, 4. Methods: Transphyseal ACL reconstruction with autograft hamstrings was performed in 27 skeletally immature patients. The average age at surgery was 13 years (range, 12-16 years), and the average follow-up time was 10.6 years (range, 10-13 years). Clinical outcomes were assessed with preoperative and final follow-up Tegner, International Knee Documentation Committee (IKDC) subjective, and Lysholm scores. Surgery details, return to sports, and ACL reconstruction failures were collected. The anteroposterior knee laxity was assessed by arthrometry, and the presence of deformities and lower limb length discrepancies were evaluated by radiographs. The presence of degenerative signs on anteroposterior and lateral knee radiographs at final follow-up was also evaluated. Results: Transphyseal ACL reconstruction was performed with vertically oriented tunnels, 7 to 10 mm in diameter, using semitendinosus-gracilis autograft. The average preoperative Tegner, IKDC, and Lysholm scores were 7, 55, and 40, respectively. Significant differences in these scores were observed at the time of the final assessment (Tegner, 6 [P = .026]; IKDC, 94 [P < .001]; Lysholm, 92 [P < .001]). Two patients reported instability during sports activity. Three patients had a rupture of the ACL graft. No leg length discrepancy, axis malalignment, or degenerative changes were observed. Conclusion: The transphyseal ACL reconstruction in skeletally immature patients is a safe option, with high functional and satisfaction results, without significant growth plate damage in this series of patients.

Radiographic evaluation of factors affecting bearing dislocation in the domed lateral Oxford unicompartmental knee replacement.

The rate of bearing dislocation with the domed lateral Oxford Unicompartmental Knee Replacement (OUKR) in different series varies from 1% to 6% suggesting that dislocation is influenced by surgical technique. The aim of this study was to identify surgical factors associated with dislocation. Aligned post-operative antero-posterior knee radiographs of seven knees that had dislocated and 87 control knees were compared. Component alignment and position and the alignment of the knee were assessed. All bearing dislocations occurred medially over the tibial wall. Knees that dislocated tended to be overcorrected: Compared with those that did not dislocate, they were in 2° less valgus (p=0.019) and the tibial components were positioned 2 mm more proximal (p<0.01). Although the relative position of the centre of the femoral component and the tibial component was the same (p=0.8), in the dislocating group the gap between the edge of the femoral component and the top of the wall in flexion was 3mm greater (p=0.019) suggesting that the components were internally rotated. To minimise the risk of dislocation it is recommended that the knee should not be overstuffed. This is best achieved by selecting the bearing thickness that just tightens the ligaments in full extension, and re-cutting the tibia if necessary. In addition to minimise the gap between the femoral and tibial components through which the bearing dislocates, the femoral component should be implanted in neutral rotation and should not be internally rotated. Level IV.

Ultrasonographic Examination of Patella

A 52-year-old female patient presented to the emergency department (ED) complaining of knee pain after falling. Upon admission to the ED, vital signs of the patient were normal. Physical examination revealed mild swelling and tenderness on the right patella, limitation of motion of the knee, and difficulty walking. Neurovascular examination was within normal limits. Bedside ultrasonographic examination (Mindray® M5, Color Diagnostic Ultrasound System, China) was performed before X-rays (Figure 1). Figure 1 Cortical disruption (arrow) and hematoma (asterisk) of patella with longitudinal ultrasonography view. DIAGNOSIS: Fracture of Patella Patellar fractures account for 1% of all skeletal fractures and is most common between the ages of 20–50.[1] The most observed fracture pattern is transverse. It generally occurs as a result of the implementation of direct force, fall on a flexed knee, or strong contraction of the quadriceps. The anteroposterior x-ray helps assess the fracture pattern and the direction of displacement, while the lateral and Merchant views assist in understanding the amount and location of comminution. In case of failure of direct radiography, other techniques can be used including computed tomography, magnetic resonance imaging or scintigraphy. Bedside ultrasonography in the diagnosis of fractures is frequently used by emergency medicine physicians. 2, 3 It may be guiding in the diagnosis of fractures especially in unstable patients. In addition, it has a major advantage in that it can be used if radiation exposure is a concern in certain situations such as children and pregnancy. Also, it can be applied in a short time and at bedside. Therefore, ultrasonography can provide rapid diagnosis in busy emergency departments. Interestingly, there was a case report demonstrating the use of ultrasonography to identify the transverse fracture of the patella.[4] Currently, standard radiographs are being used as a first imaging modality in patients with a suspected fracture. To our knowledge, there has been no clinical study that has diagnosed patella fractures with a bedside ultrasound. The case report presented here underscores the impact of ultrasonography on the diagnosis of patella fractures as well as bone injuries. In our case, standard anteroposterior and lateral knee radiographs were obtained after ultrasonographic examination (Figure 2). The patient who underwent consultation at the orthopedic clinic was prescribed a conservative treatment consisting of rest, ice, immobilization with a cylinder cast from the groin to the ankle, keeping the knee in extension, and non-steroidal anti-inflammatory drugs. Figure 2 (a) Anteroposterior knee radiography. (b) Lateral knee radiograph shows transverse fracture of the patella.

The relationship between radiological severity and functional status in patients with knee osteoarthritis

In this study, we aimed to explore the relationship between radiological findings and functional status in patients with knee osteoarthritis (OA). In this study, 117 female patients diagnosed with knee osteoarthritis according to the ACR criteria were included. Antero-posterior knee radiographs of the patients were graded according to Kellgren-Lawrence, and functional capacity was evaluated with WOMAC and Lequesne indexes. Quadriceps and hamstring muscle strengths were also concentrically measured using an isokinetic dynamometer, five repetitions at 90°/s and 20 repetitions at 180°/s. In this study, a significant relationship was determined between the age, weight, praying period, and pain period of the patients with the radiological findings. No significant relationship was determined between the functional capacity of knee and muscle strength and the radiological findings. However, left hamstring functioning capacity was found as lower in the group with the radiological findings. The radiological findings in knee OA are not associated with decrease in knee muscle strength and functional capacity. Clinical symptoms such as pain, decrease in range of motion, etc. in knee OA may be responsible for decrease in knee muscle strength and functional capacity.

Involvement of BDNF in knee osteoarthritis: the relationship with inflammation and clinical parameters

The aim of this study was to analyze the levels of brain-derived neurotrophic factor (BDNF) in both the plasma and synovial fluid of patients with primary knee osteoarthritis compared with control individuals and to investigate the relationship between BDNF levels and self-reported pain. Twenty-seven patients with knee osteoarthritis (OA) and 19 healthy subjects were enrolled in the study. Anteroposterior knee radiographs were taken to determine the disease severity of the affected knee. Radiographic grading of OA in the knee was performed using the Kellgren-Lawrence criteria. The BDNF levels in the plasma and synovial fluid were measured by enzyme-linked immunosorbent assay. The mean plasma BDNF levels of the knee OA patients were significantly higher than that of the healthy controls (2,378 ± 1,067.2 vs. 1,756 ± 804.3 pg/mL, p < 0.05). BDNF levels in the synovial fluid of OA patients (358.9 ± 178.4 pg/mL) were sixfold lower than in corresponding blood samples (p < 0.0001) and fourfold lower than in the plasma of healthy controls (p < 0.0001). Subsequent analyses showed that the plasma BDNF levels significantly correlated with self-reported pain (Western Ontario and McMaster Universities Osteoarthritis Index) (r s = 0.39, p = 0.04). Furthermore, no correlation was found between the plasma and synovial fluid BDNF concentrations and knee OA severity. The findings of this study suggest that systemic BDNF levels are most likely associated with the mechanism of joint pain in knee OA in the acute stage of joint inflammatory process. Further studies are necessary to address the functional role of BDNF in the modulation of pain to establish new therapeutic implications.

Association between hypoxia-inducible factor-1a levels in serum and synovial fluid with the radiographic severity of knee osteoarthritis.

Osteoarthritis (OA) is primarily characterized by articular cartilage degradation. Hypoxia-inducible factor-1a (HIF-1a), a subunit of the basic helix-loop-helix-containing PER-ARNT-SIM (PAS) domain transcription factors, plays a vital role in the survival of articular chondrocytes to the hostile hypoxic microenvironment and complicates the progression of OA. In this study, we examined whether HIF-1a levels in the serum and synovial fluid (SF) of patients with knee OA were increased and whether the increase was correlated with the radiographic severity of the disease. A total of 278 knee OA patients and 203 healthy controls were enrolled in this study. Knee OA radiographic grading was performed according to Kellgren-Lawrence (KL) grading system by evaluating X-ray changes observed on anteroposterior knee radiography. HIF-1a levels in the serum and SF were determined using an enzyme-linked immunosorbent assay. Serum HIF-1a levels in patients with knee OA were higher than those in healthy controls. Knee OA patients with KL grade 4 showed significantly elevated HIF-1a levels in the serum and SF compared with those with KL grades 2 and 3. Knee OA patients with KL grade 3 showed significantly higher SF levels of HIF-1a than those with KL grade 2. HIF-1a levels in the serum and SF of knee OA patients were significantly correlated with disease severity according to KL grading criteria. HIF-1a levels in the serum and SF were closely related to the radiographic severity of OA and may serve as an alternative biomarker for the progression and prognosis of knee OA.

Ultrasonographic assessment of the femoral cartilage in osteoarthritis patients with and without osteoporosis

The relationship between osteoporosis (OP) and osteoarthritis (OA) is yet unclear. To evaluate the possible effect of OP on the femoral cartilage thickness in female patients with knee OA. Eighty patients with a diagnosis of knee OA were enrolled. Forty subjects who also had OP comprised Group I and the remaining 40 OA subjects comprised Group II. Antero-posterior knee radiographs were obtained in standing position and they were evaluated according to Kelgren-Lawrence (K-L) grading scale. Femoral cartilage evaluations were performed using a linear array US probe (7-12 MHz). In addition, ultrasonographic femoral cartilage grading was also performed for each knee. Left knee scores pertaining to both gradings were found to be lower (p = 0.02, p = 0.04, respectively) in Group I when compared with those of Group II. The two grading scores were positively correlated for both knees-statistically significant only for the right side (r = 0.727, p = 0.01). No significant difference was found between the groups in terms of femoral cartilage thicknesses (all p > 0.05). Ultrasonographic and roentgenographic gradings were consistent and patients with OP had lower scores for both gradings. On the other hand, the presence of OP did not seem to have any effect on cartilage thickness measurements. To the best knowledge of the authors, this study is the first to have explored the impact of OP on OA using US in the literature.