Synovial Plica Syndrome of the Knee: A Commonly Overlooked Cause of Anterior Knee Pain.
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ABSTRACT: Synovial plica syndrome (SPS) occurs in the knee, when an otherwise normal structure becomes a source of pain due to injury or overuse. Patients may present to general practitioners, physiotherapists, or surgeons with anterior knee pain with or without mechanical symptoms, and the diagnosis can sometimes be difficult. Several studies have examined the epidemiology, diagnosis, and treatment of SPS. We review these resources to provide an evidence-based guide to the diagnosis and treatment of SPS of the knee.
Project description:IntroductionAnterior knee pain (AKP) may persist after total knee arthroplasty (TKA), even if well aligned and stable, and is reported in up to 30% of patients, leading to patient dissatisfaction. The gender-specific knee prostheses have been designed to reduce femoral component overhanging in females and improve patient satisfaction. The purpose of this study was to determine AKP between gender-specific knee prosthesis and unisex knee prosthesis following minimally invasive surgery (MIS) TKA with patellar resurfacing.MethodsThis study was a randomized trial comparing a gender-specific vs. unisex knee prosthesis in females with knee osteoarthritis. Follow-up occurred at 6 weeks, 3 months, 6 months, 1 year, and 2 years. Pre- and postoperative AKP were measured at each follow-up. Intraoperative lateral overhanging of the femoral component and patellar tracking were also measured and compared between the two groups.ResultsSixty females were recruited; 30 underwent gender-specific knee prosthesis (Gp1) and 30 underwent unisex knee prosthesis (Gp2). No patients were lost to follow-up. The incidence rates of AKP and visual analog scale AKP pain scores at 2 years were 7 vs. 7% (p = 1.00) and 0.95 ± 0.31 (0-1) points vs. 1.10 ± 0.28 (0-1) points (p = 0.68) for gender and unisex prostheses, respectively. Patellar tilt and patellar shift were similar between the two groups. Patellar tilt and patellar shift were 2.56° ± 2.03 (0-8) vs. 2.67° ± 2.35 (0-9) (p = 0.46) and 1.25 ± 1.09 (0-3.2) mm vs. 1.15 ± 0.97 (0-2.9) mm (p = 0.34) for Gp1 and Gp2, respectively. Mean lateral femoral overhanging was 0.23 ± 0.63 mm (range: 1-2 mm, Gp1) vs. 1.57 ± 1.36 mm (range: 1-3 mm, Gp2) (p ≤ 0.001).ConclusionBoth types of prostheses had similar incidence rates of AKP, VAS scores for AKP. Lateral femoral overhanging of ≤ 3 mm was not the cause of AKP.
Project description:Background: Synovial inflammation is associated with pain severity in patients with knee osteoarthritis (OA). The aim here was to determine in a population with knee OA, whether synovial tissue from areas associated with pain exhibited different synovial fibroblast transcriptomes, compared to synovial tissue from sites not associated with pain. A further aim was to compare differences between early and end-stage disease synovial fibroblasts. Methods: Patients with early knee OA (n=29) and end-stage knee OA (n=22) were recruited. Patient reported pain was recorded by questionnaire and using an anatomical knee pain map. Proton density fat suppressed MRI axial and sagittal sequences were analysed and scored for synovitis. Synovial tissue was obtained from the medial and lateral parapatellar and suprapatellar sites. RNA sequencing was performed using Illumina’s NextSeq 500 and analysed with Galaxy web platform, usegalaxy.org, and Qlucore software. Transcriptomes were functionally characterised using Ingenuity Pathway Analysis. Findings: Parapatellar synovitis was significantly associated with increased OA pain perception. Functional pathway analysis revealed that early OA painful sites mediate immune cell recruitment and promote the formation and development of neurites. Conclusion: OA disease progression and the presence of pain in early OA is associated with different synovial pathotypes. Further interrogation of these pathotypes will increase our understanding of the role of synovitis in OA joint pain and provide a rationale for the therapeutic targeting to alleviate pain in patients.
Project description:PurposeThe purpose of this study was to develop a multidisciplinary guideline for patellofemoral pain (PFP) and patellar tendinopathy (PT) to facilitate clinical decision-making in primary and secondary care.MethodsA multidisciplinary expert panel identified questions in clinical decision-making. Based on a systematic literature search, the strength of the scientific evidence was determined according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method and the weight assigned to the considerations by the expert panel together determined the strength of the recommendations.ResultsAfter confirming PFP or PT as a clinical diagnosis, patients should start with exercise therapy. Additional conservative treatments are indicated only when exercise therapy does not result in clinically relevant changes after six (PFP) or 12 (PT) weeks. Pain medications should be reserved for cases of severe pain. The additional value of imaging assessments for PT is limited. Open surgery is reserved for very specific cases of nonresponders to exercise therapy and those requiring additional conservative treatments. Although the certainty of evidence regarding exercise therapy for PFP and PT had to be downgraded ('very low GRADE' and 'low GRADE'), the expert panel advocates its use as the primary treatment strategy. The panel further formulated weaker recommendations regarding additional conservative treatments, pain medications, imaging assessments and open surgery ('very low GRADE' to 'low GRADE' assessment or absence of scientific evidence).ConclusionThis guideline recommends starting with exercise therapy for PFP and PT. The recommendations facilitate clinical decision-making, and thereby optimizing treatment and preventing unnecessary burdens, risks and costs to patients and society.Level of evidenceLevel V, clinical practice guideline.
Project description:ContextCauses of anterior knee pain (AKP) in jumping athletes include patellofemoral pain and patellar tendinopathy. The differential diagnosis of AKP is challenging, with variations in clinical presentations. No previous research has used pain location to describe AKP in basketball players.ObjectiveTo (1) describe the prevalence and pain distribution of AKP in collegiate basketball players and (2) report the prevalence of focal inferior pole pain using 2 outcome measures.DesignCross-sectional study.SettingUniversity and collegiate basketball facilities in Alberta, Canada.Patients or other participantsA total of 242 collegiate basketball athletes (138 women, 104 men).Main outcome measure(s)The single-legged decline squat test (SLDS) was used to capture pain location via pain mapping (dichotomized as focal or diffuse) and pain severity (numeric rating scale). The Oslo Sports Trauma Research Centre Knee questionnaire (OSTRC-Knee) and adapted version for patellar tendinopathy (OSTRC-Patellar Tendinopathy Questionnaire [OSTRC-P]) were used to report the prevalence of AKP and patellar tendinopathy, respectively. Focal inferior pole pain during the SLDS was used to classify patellar tendinopathy.ResultsOf the 242 players, 146 (60%) reported pain with the SLDS (unilateral = 64 [26%]; bilateral = 82 [34%]). A total of 101 (43%) described knee pain using the OSTRC-Knee. Pain mapping captured the variability in pain locations. Diffuse pain was more prevalent (left, 70%; right, 72%) than focal pain (left, 30%; right, 28%). Low prevalence of patellar tendinopathy was noted using the OSTRC-P (n = 21, 8.7%) and inferior pole pain during the SLDS (n = 25, 10.3%).ConclusionsDiffuse AKP was common in Canadian basketball players; however, pain mapped to the inferior pole of the patella was not common. Few players reported tendinopathy using the OSTRC-P, suggesting that patellar tendinopathy was not a primary knee pain presentation in this jumping cohort. Pain location, rather than the presence or severity of pain alone, may better describe the clinical presentation of AKP in jumping athletes.
Project description:BackgroundAnterior knee pain (AKP) commonly affects both physically active and sedentary individuals and the aetiology is unknown. Altered joint position sense (JPS) impacts accurate motor action and knee joint stability. It is unclear whether people with AKP have altered JPS.ObjectiveThe aim of our study was to investigate JPS in the knees of individuals with AKP.MethodA descriptive cross-sectional study measured JPS in 25 participants with unilateral or bilateral AKP. JPS was measured using active JPS testing during single leg squat (SLS) and active knee extension (AKE) in sitting. Target angles (TA) were self-determined based on each participant's capabilities. The absolute error (AE) was the main outcome measure. Impaired JPS was classified as an AE equal to or greater than five degrees.ResultsThere were no significant differences in JPS when comparing the affected and unaffected knees in participants with AKP (p > 0.05). However, a subgroup of participants with altered knee JPS was identified. There was a tendency towards greater knee flexion in the TAs of knees without AKP.ConclusionOur results showed that JPS is not significantly more impaired in knees with AKP compared with knees without AKP in a group of individuals with AKP. A subgroup with altered JPS in knees with and without AKP was identified. This finding could be because of compensatory gait patterns and the precision of the Vicon 3D motion analysis system.Clinical implicationsJoint position sense should be assessed bilaterally in individuals with AKP.
Project description:BackgroundPain from osteoarthritis (OA) is one of the top causes of disability worldwide, but effective treatment is lacking. Nociceptive factors are released by activated synovial macrophages in OA, but depletion of synovial macrophages paradoxically worsens inflammation and tissue damage in previous studies. Rather than depleting macrophages, we hypothesized that inhibiting macrophage activation may improve pain without increasing tissue damage. We aimed to identify key mechanisms mediating synovial macrophage activation and test the role of STAT signaling in macrophages on pain outcomes in experimental knee OA.MethodsWe induced experimental knee OA in rats via knee destabilization surgery, and performed RNA sequencing analysis on sorted synovial tissue macrophages to identify macrophage activation mechanisms. Liposomes laden with STAT1 or STAT6 inhibitors, vehicle (control), or clodronate (depletion control) were delivered selectively to synovial macrophages via serial intra-articular injections up to 12 weeks after OA induction. Treatment effects on knee and hindpaw mechanical pain sensitivity were measured during OA development, along with synovitis, cartilage damage, and synovial macrophage infiltration using histopathology and immunofluorescence. Lastly, crosstalk between drug-treated synovial tissue and articular chondrocytes was assessed in co-culture.ResultsThe majority of pathways identified by transcriptomic analyses in OA synovial macrophages involve STAT signaling. As expected, macrophage depletion reduced pain, but increased synovial tissue fibrosis and vascularization. In contrast, STAT6 inhibition in macrophages led to marked, sustained improvements in mechanical pain sensitivity and synovial inflammation without worsening synovial or cartilage pathology. During co-culture, STAT6 inhibitor-treated synovial tissue had minimal effects on healthy chondrocyte gene expression, whereas STAT1 inhibitor-treated synovium induced changes in numerous cartilage turnover-related genes.ConclusionThese results suggest that STAT signaling is a major mediator of synovial macrophage activation in experimental knee OA. STAT6 may be a key mechanism mediating the release of nociceptive factors from macrophages and the development of mechanical pain sensitivity. Whereas therapeutic depletion of macrophages paradoxically increases inflammation and fibrosis, blocking STAT6-mediated synovial macrophage activation may be a novel strategy for OA-pain management without accelerating tissue damage.
Project description:Background: Anterior knee pain is a common complaint amongst adolescents, which can both be persistent, and in some cases, disabling. This study investigated a series of potential risk factors potentially linked to the onset of anterior knee pain. Methods: Questionnaires were distributed amongst 367 10-15 years-olds enrolled in the local school board. These surveys included questions on sex, age, sport participation, and history of anterior knee pain verified by a physician. Bivariate correlations and a binomial logistic regression were conducted. Overall rate of AKP in the population studied was 7.4%. The results indicated that past history of knee pain, age, and increased sports participation significantly correlated with increased risk of AKP. AKP was significantly more common in females than males. While sex, height, age, overall sport participation, participation in specific sports, and history of knee injury all contributed to the binomial model.
Project description:BackgroundInflammatory mediators in the synovial fluid (SF) play critical roles in the initiation and development of pain in knee osteoarthritis (KOA). However, data for inflammatory marker expression are conflicting, and the role of SF inflammatory mediators in neuropathic pain is not clear. Therefore, the aim of this study was to identify SF inflammatory mediators associated with nociceptive and neuropathic pain in KOA.MethodsLevels of IL-1β, IL-6, TNF-α, macrophage colony-stimulating factor, MMP-3, MMP-13, metalloproteinase with thrombospondin motifs 5, calcitonin gene-related peptide, neuropeptide Y, substance P and bradykinin were measured using enzyme-linked immunosorbent assays in 86 patients. Nociceptive pain was assessed using the numeric rating scale (NRS), visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score. Neuropathic pain was determined using the PainDETECT questionnaire. Moreover, knee function was evaluated by the WOMAC score and range of motion (ROM) assessments. Radiological grade was defined using the Kellgren-Lawrence (K-L) grading scale.ResultsPain scores measured using different methods correlated highly with each other. A worse K-L grade and knee function were associated with worse pain. Expression of IL-1β and IL-6 was increased in the early stage compared with the late stage. The NRS score correlated positively with age, K-L grade, and the WOMAC score and negatively with ROM and TNF-α expression. The VAS correlated positively with age, K-L grade, and the WOMAC score but negatively with ROM and levels of IL-1β, IL-6 and TNF-α. The WOMAC pain score did not correlate with any of the inflammatory mediators measured; it correlated only with ROM. The PainDETECT score correlated only with the WOMAC score. Expression of other inflammatory mediators did not correlate with any of the pain scores.ConclusionsIL-1β, IL-6 and TNF-α play critical roles in pain in the early stage of KOA and correlate with pain. The catabolic enzymes and neuropeptides measured do not correlate with nociceptive and neuropathic pain. New biomarkers related to pain in the late stage need to be further investigated.
Project description:PurposeTo identify the best internal structure of the Brazilian version of the Anterior Knee Pain Scale (AKPS), comparing different instrument structures (structural validity) and correlating the scores of the versions (criterion validity).MethodsWe included Brazilian volunteers, aged ≥ 18 years, with patellofemoral pain (PFP) for at least 3 months. We used the confirmatory factor analysis and considered the following fit indices: chi-square/degrees of freedom (DF), comparative fit index (CFI), Tucker-Lewis index (TLI), root mean square error of approximation (RMSEA). We considered the structure with the lowest values of the Akaike information criterion (AIC), sample size adjusted Bayesian information criterion (SABIC), and assessed criterion validity using Pearson correlation coefficient (r) to correlate the long and short versions.ResultsThe study included 101 participants, mostly women (65.3%), young adults (~ 31 years old), overweight (BMI > 25 kg/m2), incomplete higher education (37.6%), and physically active (64.4%). The original 1-domain, 13-item structure showed adequate fit indices (chi-square/GL < 3.00, TLI and CFI > 0.90, and RMSEA < 0, 08). However, items 11 and 12 had a factorial load of less than 0.23. Therefore, we excluded items 11 and 12 and found adequate fit indices (chi-square/GL < 3.00, TLI and CFI > 0.90, and RMSEA < 0, 08) and lower AIC and SABIC values. We observed a correlation coefficient above the acceptable cutoff of 0.70 (r = 0.966, p-value < 0.001) between the versions.ConclusionThe 11-item AKPS (without items 11 and 12) is the version with the most adequate internal structure and correlates satisfactorily with the long version of the instrument.