Vibroarthrographic Signal Spectral Features in 5-Class Knee Joint Classification.

Vibroarthrography (VAG) is a non-invasive and potentially widely available method supporting the joint diagnosis process. This research was conducted using VAG signals classified to five different condition classes: three stages of chondromalacia patellae, osteoarthritis, and control group (healthy knee joint). Ten new spectral features were proposed, distinguishing not only neighboring classes, but every class combination. Additionally, Frequency Range Maps were proposed as the frequency feature extraction visualization method. The results were compared to state-of-the-art frequency features using the Bhattacharyya coefficient and the set of ten different classification algorithms. All methods evaluating proposed features indicated the superiority of the new features compared to the state-of-the-art. In terms of Bhattacharyya coefficient, newly proposed features proved to be over 25% better, and the classification accuracy was on average 9% better.

A novel clinical test for assessing patellar cartilage changes and its correlation with magnetic resonance imaging and arthroscopy.

Controversy still exists regarding the best clinical assessment test for chondromalacia patellae (CMP). Our study aims to evaluate the specificity and sensitivity of a novel clinical test for CMP, the "Patella Slide Test" (PST) against the findings of magnetic resonance imaging (MRI) and arthroscopy. We included 221 consecutive patients planned for elective knee arthroscopic surgery. An MRI scan of the symptomatic knee was performed prior to surgery. On the day of surgery, each patient was examined using the PST followed by a knee arthroscopy to assess the quality of the chondral surfaces of the patellofemoral joint. The MRI and PST results were compared against the arthroscopic findings that served as the gold standard. The PST (0.89) was statistically more sensitive than MRI (0.67) in diagnosing CMP. The PST (0.89) also had a greater negative predictive value (NPV) than MRI (0.74). However, MRI (0.94) was more specific than the PST (0.85). The differences in accuracy and positive predictive value of the PST versus MRI were not statically significant. In conclusion, the PST shows high sensitivity and has a greater NPV than MRI as a clinical test for diagnosing CMP.

Evaluating anterior knee pain.

Musculoskeletal complaints account for about 20% to 30% of all primary care office visits; of these visits, discomfort in the knee, shoulder, and back are the most prevalent musculoskeletal symptoms. Having pain or dysfunction in the front part of the knee is a common presentation and reason for a patient to see a health care provider. There are a number of pathophysiological etiologies to anterior knee pain. This article describes some of the common and less common causes, and includes sections on diagnosis and treatment for each condition as well as key points.

Prevalence and clinical significance of chondromalacia isolated to the anterior margin of the lateral femoral condyle as a component of patellofemoral disease: observations at MR imaging.

OBJECTIVE: To determine the prevalence of chondromalacia isolated to the anterior margin of the lateral femoral condyle as a component of patellofemoral disease in patients with anterior knee pain and to correlate it with patient demographics, patellar shape, and patellofemoral alignment. MATERIALS AND METHODS: Retrospective study over a 1-year period reviewing the MR knee examinations of all patients who were referred for assessment of anterior knee pain. Only patients with isolated lateral patellofemoral disease were included. Age, gender, distribution of lateral patellofemoral chondromalacia, and grade of cartilaginous defects were documented for each patient. Correlation between the distribution of lateral patellofemoral chondromalacia and patient demographics, patellar shape, and indices of patellar alignment (femoral sulcus angle and modified Q angle) was then ascertained. RESULTS: There were 50 patients (22 males, 28 females) with anterior knee pain and isolated patellofemoral disease. The majority of the patients (78 %) had co-existent disease with grade 1 chondromalacia. No significant correlation was found between patients with chondromalacia isolated to the anterior margin of the lateral femoral condyle and age, gender, patellar shape, or modified Q angle (p > 0.05). However, patients with chondromalacia isolated to the anterior margin of the lateral femoral condyle had a shallower femoral sulcus angle (mean 141.8°) compared to the patients with lateral patellar facet disease (mean 133.8°) (p = 0.002). CONCLUSIONS: A small percentage of patients with anterior knee pain have chondromalacia isolated to the anterior margin of the lateral femoral condyle. This was associated with a shallower femoral sulcus angle.

Clinically insignificant association between anterior knee pain and patellofemoral lesions which are found incidentally.

BACKGROUND: Patellofemoral chondral lesions are frequently identified incidentally during the arthroscopic treatment of other knee pathologies. A role has been described for arthroscopic debridement when symptoms are known to originate from pathology of the patellofemoral joint. However, it remains unclear how to manage lesions which are found incidentally whilst tackling other pathologies. The purpose of this study was to establish the strength of association between anterior knee pain and patellofemoral lesions identified incidentally in a typical arthroscopic population. METHODS: A consecutive series of patients undergoing arthroscopy for a range of standard indications formed the basis of this cross section study. We excluded those with patellofemoral conditions in order to identify patellofemoral lesions which were solely incidental. Pre-operative assessments were performed on 64 patients, where anterior knee pain was sought by three methods: an annotated photographic knee pain map (PKPM), patient indication with one finger and by palpated tenderness. A single blinded surgeon, performed standard arthroscopies and recorded patellofemoral lesions. Statistical correlations were performed to identify the association magnitude. RESULTS: Associations were identified between incidental patellofemoral lesions and tenderness palpated on the medial patella (P = 0.007, χ(2) = 0.32) and the quadriceps tendon (P = 0.029, χ(2) = 0.26), but these associations were at best fair, which could be interpreted as clinically insignificant. CONCLUSION: Incidental patellofemoral lesions are not necessarily associated with anterior knee pain, we suggest that they could be left alone. This recommendation is only applicable to patellofemoral lesions which are found incidentally whilst addressing other pathology.

Correlation between subcutaneous knee fat thickness and chondromalacia patellae on magnetic resonance imaging of the knee.

PURPOSE: Chondromalacia patellae is a common cause of anterior knee pain in young patients and can be detected noninvasively with magnetic resonance imaging (MRI). The purpose of our study was to evaluate the correlation between subcutaneous fat thickness around the knee joint on axial MRIs as a surrogate marker of obesity, with the presence or absence of chondromalacia patellae. METHODS: A retrospective review was conducted of knee MRIs in 170 patients who satisfied the inclusion criteria. Imaging was performed over a 12-month period on a 1.5T MRI system with a dedicated extremity coil. Two radiologists experienced in musculoskeletal imaging assessed each examination in consensus for the presence or absence of chondromalacia patellae and graded positive studies from 0 (absent) to 3 (full cartilage thickness defect). Measurement of subcutaneous knee fat thickness was obtained on the medial aspect of the knee. RESULTS: MRI findings of chondromalacia patellae were present in 33 patients (19.4%), of which, there were 11 grade 1 lesions (33.3%), 9 grade 2 lesions (27.3%), and 13 grade 3 lesions (39.4%). The mean subcutaneous knee fat thickness was significantly higher in the chondromalacia patellae group for all grades compared with the normal group (P < .001), and there was a significant correlation between subcutaneous knee fat thickness and grades of chondromalacia patellae (R = 0.48 [95% confidence interval, 0.38-0.68]; P < .001). Female patients had thicker subcutaneous knee fat and more severe grades of chondromalacia patellae. CONCLUSION: Subcutaneous knee fat thickness as a surrogate marker of obesity was positively associated with the presence and severity of chondromalacia patellae on MRI.

[Unsatisfactory long-term prognosis of conservative treatment of patellofemoral pain syndrome]. / Utilfredsstillende langtidsresultater efter konservativ behandling af patellofemoralt smertesyndrom.

This review overviews the long-term prognosis of conservatively treated patients with patellofemoral pain syndrome (PFPS). Median values of the 16 included studies show that 29% of soldiers, 27.8% of sports active and 24,7% of the general public will become pain free after they are diagnosed with PFPS. 21.5% of sports active and 23% of the general public diagnosed with PFPS will stop participating in sports because of knee pain. There is an indication that around one third diagnosed with PFPS will become pain free and one fourth will stop participating in sports because of knee pain.

Condromalácia patelar: análise de quatro testes clínicos / Chondromalacia patella: analysis of four clinical tests

Introdução: Condromalácia patelar (CP) é a perda da cartilagem de uma ou mais porções da patela, agravada por atividades que aumentam a compressão entre a patela e o fêmur. Objetivo: Analisar quatro testes clínicos para CP em indivíduos com e sem CP. Método: Foram avaliados 52 indivíduos: 28 com condromalácia e 24 sem. O diagnóstico foi determinado por raio-x (22), ressonância magnética (9) e ultrassom (4). Foi feita anamnese e exame físico, onde aplicaram-se os testes de Waldron (TW), apreensão patelar (AP), Sinal de Frund (SF) e Sinal de Clarke (SC). Resultados: SF e SC identificaram o maior número de sujeitos (12) com CP, seguido do TW (10) e o AP (7). Entretanto, os testes também evidenciaram resultados falso-positivos (SC ? 12; SF ? 4; TW ? 2 e AP -1) Conclusão: Os testes clínicos utilizados nesse estudo foram inconsistentes, evidenciando resultados falso-positivos, sugerindo cautela na sua utilização como indicadores da CP.

Introduction: chondromalacia patella (CP) is the loss of cartilage of one or more portions of the patella, aggravated by activities that increase the compression between the patella and femur. Objective: To assess four clinical trials for lung cancer for individuals with and without CP. Methods: We studied 52 subjects: 28 with and 24 without chondromalacia. The diagnosis was determined by X-ray (22), MRI (9) and ultrasound (4). Was made medical history and physical examination, where we applied tests Waldron (TW), patellar apprehension (AP) Signal Fründe (SF) and Signal Clarke (SC). Results: SF and SC identified the largest number of subjects (12) with CP, followed by TW (10) and AP (7). However, tests also showed false-positive results (SC - 12, SF - 4, TW - 2, AP -1) Conclusion: The clinical tests used in this study were inconsistent, showing false positive results, suggesting caution in its use as Indicators of CP.

Evaluation of the chondromalacia patella using a microscopy coil: comparison of the two-dimensional fast spin echo techniques and the three-dimensional fast field echo techniques.

OBJECTIVE: We wanted to compare the two-dimensional (2D) fast spin echo (FSE) techniques and the three-dimensional (3D) fast field echo techniques for the evaluation of the chondromalacia patella using a microscopy coil. MATERIALS AND METHODS: Twenty five patients who underwent total knee arthroplasty were included in this study. Preoperative MRI evaluation of the patella was performed using a microscopy coil (47 mm). The proton density-weighted fast spin echo images (PD), the fat-suppressed PD images (FS-PD), the intermediate weighted-fat suppressed fast spin echo images (iw-FS-FSE), the 3D balanced-fast field echo images (B-FFE), the 3D water selective cartilage scan (WATS-c) and the 3D water selective fluid scan (WATS-f) were obtained on a 1.5T MRI scanner. The patellar cartilage was evaluated in nine areas: the superior, middle and the inferior portions that were subdivided into the medial, central and lateral facets in a total of 215 areas. Employing the Noyes grading system, the MRI grade 0-I, II and III lesions were compared using the gross and microscopic findings. The sensitivity, specificity and accuracy were evaluated for each sequence. The significance of the differences for the individual sequences was calculated using the McNemar test. RESULTS: The gross and microscopic findings demonstrated 167 grade 0-I lesions, 40 grade II lesions and eight grade III lesions. Iw-FS-FSE had the highest accuracy (sensitivity/specificity/accuracy = 88%/98%/96%), followed by FS-PD (78%/98%/93%, respectively), PD (76%/98%/93%, respectively), B-FFE (71%/100%/93%, respectively), WATS-c (67%/100%/92%, respectively) and WATS-f (58%/99%/89%, respectively). There were statistically significant differences for the iw-FS-FSE and WATS-f and for the PD-FS and WATS-f (p < 0.01). CONCLUSION: The iw-FS-FSE images obtained with a microscopy coil show best diagnostic performance among the 2D and 3D GRE images for evaluating the chondromalacia patella.

Reliability of clinical findings and magnetic resonance imaging for the diagnosis of chondromalacia patellae.

BACKGROUND: This diagnostic study was performed to determine the correlation between anterior knee pain and chondromalacia patellae and to define the reliability of magnetic resonance imaging for the diagnosis of chondromalacia patellae. METHODS: Fifty-six young adults (median age, 19.5 years) with anterior knee pain had magnetic resonance imaging of the knee followed by arthroscopy. The patellar chondral lesions identified by magnetic resonance imaging were compared with the arthroscopic findings. RESULTS: Arthroscopy confirmed the presence of chondromalacia patellae in twenty-five (45%) of the fifty-six knees, a synovial plica in twenty-five knees, a meniscal tear in four knees, and a femorotibial chondral lesion in four knees; normal anatomy was seen in six knees. No association was found between the severity of the chondromalacia patellae seen at arthroscopy and the clinical symptoms of anterior knee pain syndrome (p = 0.83). The positive predictive value for the ability of 1.0-T magnetic resonance imaging to detect chondromalacia patellae was 75% (95% confidence interval, 53% to 89%), the negative predictive value was 72% (95% confidence interval, 56% to 84%), the sensitivity was 60% (95% confidence interval, 41% to 77%), the specificity was 84% (95% confidence interval, 67% to 93%), and the diagnostic accuracy was 73% (95% confidence interval, 60% to 83%). The sensitivity was 13% (95% confidence interval, 2% to 49%) for grade-I lesions and 83% (95% confidence interval, 59% to 94%) for grade-II, III, or IV lesions. CONCLUSIONS: Chondromalacia patellae cannot be diagnosed on the basis of symptoms or with current physical examination methods. The present study demonstrated no correlation between the severity of chondromalacia patellae and the clinical symptoms of anterior knee pain syndrome. Thus, symptoms of anterior knee pain syndrome should not be used as an indication for knee arthroscopy. The sensitivity of 1.0-T magnetic resonance imaging was low for grade-I lesions but considerably higher for more severe (grade-II, III, or IV) lesions. Magnetic resonance imaging may be considered an accurate diagnostic tool for identification of more severe cases of chondromalacia patellae.

[Imaging examinations of the patellofemoral joint]. / Bildgebende Untersuchungen des Patellofemoralgelenks.

Lesions in the patellofemoral region can be caused by trauma, chronic overloading, and especially regarding cartilage alterations by normal aging or pathologic processes. Very commonly these lesions lead to early arthrosis. An accurate clinical evaluation in all these patients is recommended. The combination of clinical information and radiological examinations should end up with an exact diagnosis.As part of the radiological evaluation of complaints of the patellofemoral region MR imaging is of special value since this method allows direct visualization of all intra- and extra-articular structures and their alterations, ultimately aiding in planning sufficient therapy. Moreover, is it possible to exclude pathology by MR imaging, which helps to prevent useless treatment and surgical procedures.

The diagnostic value of the Clarke sign in assessing chondromalacia patella.

CONTEXT: Various techniques have been described for assessing conditions that cause pain at the patellofemoral (PF) joint. The Clarke sign is one such test, but the diagnostic value of this test in assessing chondromalacia patella is unknown. OBJECTIVE: To (1) investigate the diagnostic value of the Clarke sign in assessing the presence of chondromalacia patella using arthroscopic examination of the PF joint as the "gold standard," and (2) provide a historical perspective of the Clarke sign as a clinical diagnostic test. DESIGN: Validation study. SETTING: All patients of one of the investigators who had knee pain or injuries unrelated to the patellofemoral joint and were scheduled for arthroscopic surgery were recruited for this study. PATIENTS OR OTHER PARTICIPANTS: A total of 106 otherwise healthy individuals with no history of patellofemoral pain or dysfunction volunteered. MAIN OUTCOME MEASURE(S): The Clarke sign was performed on the surgical knee by a single investigator in the clinic before surgery. A positive test was indicated by the presence of pain sufficient to prevent the patient from maintaining a quadriceps muscle contraction against manual resistance for longer than 2 seconds. The preoperative result was compared with visual evidence of chondromalacia patella during arthroscopy. RESULTS: Sensitivity was 0.39, specificity was 0.67, likelihood ratio for a positive test was 1.18, likelihood ratio for a negative test was 0.91, positive predictive value was 0.25, and negative predictive value was 0.80. CONCLUSIONS: Diagnostic validity values for the use of the Clarke sign in assessing chondromalacia patella were unsatisfactory, supporting suggestions that it has poor diagnostic value as a clinical examination technique. Additionally, an extensive search of the available literature for the Clarke sign reveals multiple problems with the test, causing significant confusion for clinicians. Therefore, the use of the Clarke sign as a routine part of a knee examination is not beneficial, and its use should be discontinued.

Arthroscopic findings in knees undergoing proximal tibial osteotomy.

This study determines the occurrence of significant, arthroscopically correctable intraarticular pathology at the time of valgus-producing high tibial osteotomy for symptomatic medial compartment arthrosis with varus malalignment. Thirty consecutive patients (32 knees) scheduled for the procedure underwent concomitant knee arthroscopy. In the lateral compartment, meniscal tears occurred in 16 knees (50%), unstable chondral flaps in 4 knees (13%), and loose bodies in 3 knees (9%). In the anterior compartment, unstable chondral flaps occurred in 10 knees (31%). In the medial compartment, meniscal tears occurred in 29 knees (91%). The 5 knees with mechanical symptoms did not demonstrate a higher occurrence of loose bodies, chondral flaps, or meniscal tears compared with knees without mechanical symptoms. There was a significant occurrence of correctable pathology in all three compartments in knees undergoing valgus-producing high tibial osteotomy for the treatment of symptomatic medial osteoarthritis with varus malalignment. Prior studies have not systematically documented these findings.

MRI quantitative morphologic analysis of patellofemoral region: lack of correlation with chondromalacia patellae at surgery.

OBJECTIVE: In numerous studies, the morphologic features of the patellofemoral joint have been analyzed on radiographs. The objective of this study was to assess patellofemoral measurements on MR images and to correlate the measurements with the presence or absence of chondromalacia patellae confirmed at surgery. MATERIALS AND METHODS: Axial and sagittal MR images of 98 knees (97 patients) were evaluated. Lateral and medial patellar facet lengths, lateral-to-medial facet length ratio, and interfacet angle were measured at three levels through the patella. Trochlear depth was measured on an axial slice. Patella and patellar tendon lengths, patellar tendon-to-patella ratio, and overlap of the patellar and trochlear articular cartilages were measured on sagittal slices. These measurements in knees with chondromalacia patellae were compared with those in knees without chondromalacia patellae. For assessment of reproducibility, axial measurements were repeated by a second observer. RESULTS: There was no statistically significant difference in any of the axial and sagittal slice measurements between knees with and those without chondromalacia patellae. Interobserver reliability was excellent for measurements of trochlear depth and measurements in the superior and middle aspects of the patella. Measurements through the inferior patella were slightly less reproducible. CONCLUSION: The results of our study with MRI confirmed many previous radiographic findings. Although we did not find correlation between the presence of chondromalacia patellae and the patellofemoral indexes we analyzed, it is possible that the results of further investigations incorporating different grades of chondromalacia and different locations along the patellar articular surface may lead to further insight regarding the morphologic risk factors for chondromalacia patellae.

Condromalácia de patela: comparação entre os achados em aparelhos de RM de alto e baixo campo magnético / Chondromalacia patellae: comparison of high-field strength versus low-field strength magnetic resonance imaging findings

OBJETIVO: Comparar os aparelhos de ressonância magnética de baixo campo e de alto campo para estudo da cartilagem articular da patela. MATERIAIS E MÉTODOS: Foi realizado estudo usando as seqüências GRE 2D, GRE 3D, FSE T2 e STIR (baixo campo) e TSE T2 SPIR. Cada seqüência foi analisada separadamente para o estudo da cartilagem, sem o conhecimento dos dados do paciente e do resultado das outras seqüências, sendo atribuído grau de lesão de 0 a 3 e descrita a sua localização. Os resultados de concordância e discordância foram analisados pelos testes de Kappa e McNemar. RESULTADOS: Na faceta medial houve baixas concordâncias e as discordâncias mostraram significativa superestimação. Na faceta lateral houve boas concordâncias e as discordâncias não foram significativas. No ápice houve boas concordâncias e as discordâncias mostraram significativa subestimação. CONCLUSÃO: A seqüência STIR teve a melhor concordância com a seqüência TSE T2 SPIR. Lesões de alto grau são mais bem caracterizadas pelas seqüências do aparelho de baixo campo. Areas de aumento de sinal dificultam o estudo da cartilagem da faceta medial da patela no aparelho de baixo campo.

OBJECTIVE: To compare the performance of low-field-strength and high-field-strength magnetic resonance imaging equipments for evaluation of the patella articular cartilage. MATERIALS AND METHODS: The study was developed using GRE 2D, GRE 3D, FSE T2, STIR sequences (low-field) and TSE T2 SPIR sequence. Each sequence has been separately analyzed for evaluation of the cartilage without knowledge of other sequences results or any patients data; the lesion was assigned a grade from 0 to 3 and had its location defined. Agreement and disagreement results were analyzed by Kappa and McNemar tests. RESULTS: Medial facet has presented low agreement index and disagreements showed to be significantly overestimated. Lateral facet has presented a reasonable agreement index and disagreement index was not significant. Medial ridge has presented a reasonable agreement index and disagreement index has showed to be underestimated. CONCLUSION: The STIR sequence versus TSE T2 SPIR sequence has presented the higher agreement index. High grade lesions are better characterized by low-field-strength magnetic resonance imaging equipment sequences. Areas of increased signal intensity make difficult the study of the patella medial facet cartilage in low-field-strength equipment.

Ressonância magnética no diagnóstico da condromalácia de patela: [revisão] / Use of magnetic resonance imaging in the diagnosis of chondromalacia patella: [revision]

As lesões da cartilagem articular da patela são bastante comuns, e em virtude da dissociação entre os sintomas e sinais e o estágio das lesões condrais o exame de escolha inicial é a ressonância magnética, sendo importante para o radiologista estar habituado às alterações condrais nesta doença para o correto diagnóstico.

Patellar articular cartilage lesions are very common and due to the dissociation between signs and symptoms and the stage of the chondral lesions the diagnostic method of choice is magnetic resonance imaging. Therefore, radiologists shold be familiar with chondral abnormalities in order to correctly diagnose this condition.