Patella-patellar tendon angle and lateral patella-tilt angle decrease patients with chondromalacia patella.

PURPOSE: The aim of the present study was to evaluate the effect of patellofemoral joint morphology and patellar alignment (lateral patellar tilt and sagittal patellar tilt) on the presence and stage of CP, and identify the differences between sexes. METHODS: MRI of 243 patients [146 men (60.1%)] were evaluated retrospectively. Patients were grouped as normal group without chondromalacia, group with mild chondromalacia (grades 1-2) and group with severe chondromalacia (grades 3-4). Sagittal patellofemoral alignment was assessed by the angle between the patella and patellar tendon (P-PTA), and the angle between the quadriceps tendon and patella (Q-PA). Patellar tilt was assessed by lateral patellar tilt angle (LPTA). In addition, patellofemoral joint morphology was evaluated by measuring trochlear depth (TD), trochlear sulcus angle (TSA) and patella angle (PA). RESULTS: P-PTA, Q-PA, LPTA and TD values were significantly lower in patients with severe chondromalacia than in patients with both normal and mild chondromalacia (P < 0.001). TSA values were significantly higher in patients with severe chondromalacia than those with both normal and mild chondromalacia (P < 0.001). TSA was higher and TD was lower in women compared to men (P < 0.001). LPTA and P-PTA were lower in women compared to men, and the difference was significant. There was no difference in PA between the two sexes. CONCLUSIONS: Patellar cartilage degeneration increases with trochlear dysplasia. There is a strong correlation between patellar malalignment (lateral patellar tilt and sagittal patellar tilt) and chondromalacia patella. Women are more prone to developing CP than men.

Analysis and multiclass classification of pathological knee joints using vibroarthrographic signals.

BACKGROUND AND OBJECTIVE: Vibroarthrography (VAG) is a method developed for sensitive and objective assessment of articular function. Although the VAG method is still in development, it shows high accuracy, sensitivity and specificity when comparing results obtained from controls and the non-specific, knee-related disorder group. However, the multiclass classification remains practically unknown. Therefore the aim of this study was to extend the VAG method classification to 5 classes, according to different disorders of the patellofemoral joint. METHODS: We assessed 121 knees of patients (95 knees with grade I-III chondromalacia patellae, 26 with osteoarthritis) and 66 knees from 33 healthy controls. The vibroarthrographic signals were collected during knee flexion/extension motion using an acceleration sensor. The genetic search algorithm was chosen to select the most relevant features of the VAG signal for classification. Four different algorithms were used for classification of selected features: logistic regression with automatic attribute selection (SimpleLogistic in Weka), multilayer perceptron with sigmoid activation function (MultilayerPerceptron), John Platt's sequential minimal optimization algorithm implementation of support vector classifier (SMO) and random forest tree (RandomForest). The generalization error of classification algorithms was evaluated by stratified 10-fold cross-validation. RESULTS: We obtained levels of accuracy and AUC metrics over 90%, more than 93% sensitivity and more than 84% specificity for the logistic regression-based method (SimpleLogistic) for a 2-class classification. For the 5-class method, we obtained 69% and 90% accuracy and AUC respectively, and sensitivity and specificity over 91% and 69%. CONCLUSIONS: The results of this study confirm the high usefulness of quantitative analysis of VAG signals based on classification techniques into normal and pathological knees and as a promising tool in classifying signals of various knee joint disorders and their stages.

Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella.

PURPOSE: The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis. METHODS: Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis. RESULTS: The mean age of all participants was 52.9 ± 8.2 years. The mean P-PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p < 0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models. CONCLUSION: This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities. LEVEL OF EVIDENCE: IV.

T2 mapping in patellar chondromalacia.

OBJECTIVE: To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia. METHODS: This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16-45 years). MRI of 97 knees were performed in these patients at 1.5T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet-proximal-lateral (EPL), external facet-proximal-central (EPC), internal facet-proximal-central (IPC), internal facet-proximal-medial (IPM), 4 in the middle section (external facet-middle-lateral (EML), external facet-middle-central (EMC), internal facet-middle-central (IMC), internal facet-middle-medial (IMM) and 4 distal (external facet-distal-lateral (EDL), external facet-distal-central (EDC), internal facet-distal-central (IDC), internal facet-distal-medial (IDM). RESULTS: T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (p<0.05), except in the internal distal facet (IDC and IDM), EPC, EDL, and IMM. Severe chondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (p<0.05). CONCLUSIONS: Steepest increase in T2 values of patellar cartilage occurs in early stages of patellar cartilage degeneration. Progression of morphologic changes of chondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the central area of the middle section, where T2 values remain increased.

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.

Sensitivity of MRI for articular cartilage lesions of the patellae.

BACKGROUND AND AIMS: Reliable diagnosis of articular cartilage lesions of the patellae is often based on arthroscopy. However, unnecessary arthroscopies should be avoided. The aim of this study was to assess the sensitivity and applicability of MRI to diagnosing articular cartilage lesions of the patellae. MATERIALS AND METHODS: We identified 74 consecutive males (mean age 21 years, range 18-28) from the medical records of our institute with the sole diagnosis of articular cartilage lesions of the patellae based on arthroscopy. Magnetic resonance imaging was performed with 1.0 Tesla scanner a mean of 4 weeks before arthroscopy. Sensitivity of symptoms, and MRI for the diagnosis was calculated. RESULTS: Based on arthroscopy, 20 (27%) cases of cartilage lesions of the patellae were grade-I, 32 (43%) were grade-II, and 22 (30%) were grade-III. MRI revealed cartilage lesions of the patellae in 49 knees (66%), indicating that the sensitivity of MRI was 66% (95% CI: 53%-74%). MRI sensitivity increased with the severity of chondral lesions: all grade III to IV lesions were detected (sensitivity 100%, 95% CI: 85%-100%) by MRI. Grade of articular cartilage lesions of the patellae based on arthroscopy was not associated with clinical symptoms (p=0.61). CONCLUSIONS: The sensitivity of 1.0 Tesla MRI for detecting grade-I lesions was low and could not be used to confirm the diagnosis of articular cartilage lesions of the patellae. For the detection of more severe grade-II to III lesions, the MRI sensitivity was markedly higher. MRI may thus be considered an accurate diagnostic tool for identifying more severe cases of articular cartilage lesions of the patellae.

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.

Evaluation of magnetic resonance signal modification induced by hyaluronic acid therapy in chondromalacia patellae: a preliminary study.

Hyaluronic Acid (HA) is an alternative method for the treatment of osteoarthritis (OA), which acts on pain through a double action: anti-inflammatory and synovial fluid (SF) visco-supplementation. Magnetic Resonance Imaging (MRI), utilizing specific sequences, is a valid method for studying the initial phase of chondral damage. The analysis of the data, obtained through the intensity of values taken by positioning Region of Interest (ROIs) within the lesion, determining the differences before and after treatment with HA injected into the knee. The results obtained after six months and one year from the injection were statistically different in respect to those taken before, immediately and after three months of treatment. MRI represents a valid tool to evaluate the grade of chondromalacia patellae and also to follow the cartilage modification induced by HA therapy.

Comparación de hallazgos quirúrgicos de lesiones meniscales con hallazgos imagenológicos de RMN tratados a través de cirugía artroscopica: en IVSS Hospital Dr. Juan Montezuma Ginnari durante el período 2003-2006 / Comparison of surgical findings of meniscal injuries with RMN imaging findings of treated through arthroscopic surgery: in IVSS Hospital Dr. Juan Montezuma Ginnari during the period 2003-2006

Los meniscos son estructuras indispensables para la función normal de la rodilla, su afectación puede ser degenerativa o traumática. Se realizó un estudio retrospectivo, descriptivo y analítico que reunió 69 pacientes con meniscopatía, tratados a trevés de la cirugía Atroscópica. Se encontró relación entre hallazgos imagenológicos y quirúrgicos en cuanto a la frecuencia de lesiones del lado derecho del menisco, siendo mayormente afectado el menisco medial con 61,40 por ciento por hallazgos quirúrgicos en comparación al 51,51 por ciento de frecuencia del menisco lateral según la Resonancia magnética.

MR pharmacokinetic modeling of the patellar cartilage differentiates normal from pathological conditions.

PURPOSE: To study the pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of the patellar cartilage under normal and pathological conditions. MATERIALS AND METHODS: DCE-MRI was obtained in 22 cases. There were 17 patients with degenerative patellar conditions (eight with chondromalacia and nine with osteoarthritis) and five normal subjects. The cartilage pharmacokinetic parameters of K(trans) (vascular permeability), k(ep) (extraction ratio), upsilon(e) (extravascular extracellular space [EES] volume fraction), and upsilon(p) (intravascular space volume fraction) were extracted. RESULTS: Statistically significant differences were observed between the different groups (normal cartilage, chondromalacia and osteoarthritis) for K(trans) and upsilon(e). K(trans) values were (mean +/- SD) 1.06 +/- 0.62, 11.97 +/- 8.91, and 21.21 +/- 16.03 mL x minute(-1) x 100 mL(-1) (P < 0.02), respectively; and upsilon(e) values were 0.71 +/- 0.69, 3.59 +/- 2.21, and 10.51 +/- 8.20% (P < 0.002). Reproducibility of the pharmacokinetic calculations was assessed with a second set of analyses of 10 random cases one week after the first analysis, showing a test-retest root mean square (RMS) coefficient of variation of 9.78% for K(trans) and 14.72% for upsilon(e). CONCLUSION: The vascular permeability and EES fraction of cartilage increases with the severity of the degeneration. Pharmacokinetic models allow to study the vascular properties of the cartilage and may have applications as a surrogate index in longitudinal studies to quantify the evolution of drug trials.

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.

Retropatellar chondromalacia associated with medial osteoarthritis after meniscus injury. One year of observations in sheep.

BACKGROUND/AIMS: In an ovine meniscal repair model, the patellofemoral (PF) osteoarthritis due to a non-sutured tear or failed repair was investigated. METHODS: A radial meniscus tear was either sutured with polydioxanone (PDS), with a slow degrading polylactide long-term suture(LTS) or left without treatment. Knee joint cartilage in the PF and medial compartment was evaluated compared to normal knees (healthy controls). RESULTS: Retropatellar osteoarthritis in the non-sutured and sutured animals was intense in contrast to the control knees after 6 months in all groups (p < 0.001), and after 12 months in the PDS group (p < 0.001), LTS group and non-sutured animals (p < 0.05). CONCLUSION: Non-sutured meniscus tears and failed repair lead fast to intense PF osteoarthritis corresponding with tibial damage of the injured compartment.

In vivo study on the short-term effect of radiofrequency energy on chondromalacic patellar cartilage and its correlation with calcified cartilage pathology in an equine model.

Chondromalacia can cause joint pain and synovial effusion with the potential for developing into osteoarthritis. Thermal chondroplasty using radiofrequency energy (RFE) has been reported to be superior to mechanical debridement for treating chondromalacia. We compared short-term changes in biomechanical properties of articular cartilage after treatment with monopolar (mRFE) or bipolar RFE (bRFE) or mechanical debridement (MD) on experimentally created grade II chondromalacia patellae. Chondromalacia patellae was created arthroscopically in both patellae of 15 ponies. Ten months after surgery, each patella was randomly assigned to one of four experimental groups: sham operated, untreated control; MD; bRFE; and mRFE. Animals were euthanized 6 months after treatment and fresh osteochondral sections were collected from the treated area, the border of the chondromalacic and nonchondromalacic area, and from two untreated areas for analysis of mechanical properties. The same areas were harvested from an additional six untreated ponies. The aggregate modulus (H(A)), Poisson's ratio (nu(s)), and permeability (k) were determined for each area under creep indentation, and cartilage thickness was measured with a needle probe. The relation between zone of calcified cartilage (ZCC) and mechanical properties of hyaline cartilage (HC) was assessed histomorphometrically. Treated areas of all four groups had inferior mechanical properties compared at the same location. The treated and border areas had significantly lower H(A) values than the untreated areas. Permeability values showed significant differences between bRFE and other treated groups. Chondromalacic areas showed thinning of cartilage compared to nonchondromalacic areas. Biomechanical properties of the injured cartilage were inferior to nonchondromalacic cartilage regardless of the treatment type. mRFE had the highest stiffness value compared to other treatments and significantly higher values than MD. A significant correlation was observed between the mechanical properties of HC and ZCC thickness.

Second-look arthroscopy of cartilage changes of the patellofemoral joint, especially the patella, following acute and recurrent patellar dislocation.

OBJECTIVE: The purpose of this study was to clarify some pathogenesis of the cartilage changes of the patellofemoral joint in patellar dislocation knees. METHODS: A first arthroscopy was performed in a total of 60 knees, including 30 knees of acute patellar dislocation (APD) and 30 knees of recurrent patellar dislocation (RPD). At the time of the first arthroscopy, 58 knees sustained open medial patellofemoral ligament repair/reconstruction, and 2 knees had only arthroscopy examination. In APD knees, the second-look arthroscopy was performed 16.7 months after the first arthroscopy, and in RPD knees, 25.2 months after the first arthroscopy. RESULTS: In most APD knees, cracking primarily on the central dome of the patella did not have a remarkable change but in several knees that had a high number of cracking or interlaced cracking, cracking became worse with fibrillation. Osteochondral defect site primarily on the medial facet showed fibrillation and/or ulceration (erosion). In most RPD knees, fissuring primarily on the central dome did not have a remarkable change, and fibrillation and/or erosion mainly on the medial facet also did not have a remarkable change. However, in four knees with the continuation of patellar dislocation, the patellar cartilage changes had definitely worsened. On the other hand, in the first and second-look arthroscopy, most APD and RPD knees had no remarkable cartilage lesions or cartilage changes of the femoro-trochlear aspect. CONCLUSIONS: One of the pathogenesis of fissuring in RPD knees seems to be cracking occurring at the time of APD. Two of the pathogenesis of fibrillation may result from the reparative reaction of the cartilage in osteochondral defect site and the cartilage change due to a high degree of cracking damage mainly on the central dome in APD injury. The continuation of patellar dislocation definitely makes the patellar cartilage lesions worse.

[What factors influence the results of ACT when the indication limits are exceeded?]. / Welche Faktoren beeinflussen das Ergebnis der ACT bei Uberschreiten der Indikationsgrenzen?

AIM: The present study evaluates the results of ACT at the knee joint with transgression of the usual spectrum of indications and points out the possible limits of the method. METHODS: In 20 of a total of 71 patients the indication limits of ACT were exceeded. The clinical follow-up over two years was related to the localisation, size, adjacent cartilage, previous and additional operations and the quality of the transplanted chondrocytes. RESULTS: The average patient age at time of operation was 41.1 years (24 to 55 years). The average defect size was 7.9 cm (2) (3.75 to 14 cm (2)). In the analysed group outside of the indication limits of ACT half of the patients showed good or excellent results at clinical follow-up after 2 years. 10 patients, however, assessed the clinical situation as fair or poor. Within this group 5 patients showed a minimum of two lesions. In 6 patients the treated defect was not completely surrounded by an adjacent cartilage shoulder. In 7 cases the meniscus at the site of the lesion had been partially removed in a previous operation and osteoarthrosis or kissing lesions were detected in 4 cases. The persistent good cell quality had no negative influence on the postoperative results. CONCLUSION: The results after ACT are influenced by the adjacent cartilage shoulder, kissing lesions, previous meniscectomy and osteoarthrosis. This may limit the indications of the method.

Evaluation of patellar chondromalacia with MR: comparison between T2-weighted FSE SPIR and GE MTC.

PURPOSE: To compare two different MR sequences to tissue signal suppression in the study of patellar cartilage abnormalities. MATERIALS AND METHODS: We examined 26 patients with magnetic resonance (MR) imaging: sequences included spectral presaturation with inversion recovery (SPIR), with fat suppression and T2-weighted images, magnetization transfer contrast (MTC) sequences, T1-weighted and T2-weighted spin-echo sequences. All patients underwent conventional knee arthroscopy and in all patients a hyaline cartilage lesion was assessed in three articular zones: the patellar medial facet, the lateral facet and the patellar crista. Was assessed 78 articular facets. The lesions were classified using a standard arthroscopic grading system adapted to MR imaging: normal cartilage that corresponds to the grade 0 according to the Noyes grading system, low grade lesions that correspond to the grade I e IIa and high grade lesions that correspond to grades IIb and III. The arthroscopic results were compared with MR images. We assessed the MR diagnostic accuracy, sensitivity, specificity and MR positive predictive value and negative predictive value of the two sequences taking into consideration total lesions, and high-grade and low grade lesions separately. RESULTS: Twenty-four low grade lesions (16 grade I e 8 grade IIa) and 18 high grade lesions (10 grade IIb e 8 grade III) were diagnosed by arthroscopy. Regarding low grade and high-grade lesions together, the accuracy was 77% for MTC sequences and 90% for SPIR sequences. In identifying low-grade lesions, the sensitivity was 88% for SPIR sequence and 42% for MTC sequences. Specificity for the detection of all lesions was 89% for the SPIR sequences and 94% for the MTC sequences. The SPIR sequence visualised water content abnormalities in degenerating cartilage, which are representative of low-grade lesions. The sensitivity of the sequence enabled us to obtain improved contrast for detecting cartilage surface irregularities. The MTC sequences allowed us to grade high-grade lesions susceptible to surgery and small cartilage defects in the presence of joint fluid. The MTC sequences were insufficient in the diagnosis of early stages of chondromalacia because the suppression of the signal of bonded water reduced the contrast among areas of articular cartilage with different water content. For this reason cartilage oedema and early superficial fibrillation were not identified. CONCLUSIONS: In our experience the SPIR sequence proved superior to the MTC sequence in the identification of low grade lesions of the patellar cartilage. The overall value of such sequences in the study of articular pathology also needs to be assessed in the others sites where the articular cartilage is thinner and surfaces more curvilinear.