Comparison between magnetic resonance imaging and arthroscopy in the diagnosis of patellar cartilage lesions: a prospective study

Comparison of conventional socket attachment and bone-anchored prosthesis for persons living with transfemoral amputation - mobility and quality of life

BACKGROUND

For patients with transfemoral amputation experiencing issues with their sockets, bone-anchored prosthesis systems are an alternative and sometimes the only way to be mobile and independent. The present cross-sectional study aimed to investigate the gait performance and quality of life of a group of patients treated with bone-anchored systems compared to those of participants treated with a conventional socket-suspended prosthesis.

METHODS

A total of 17 participants with a socket-suspended and 20 with a bone-anchored prosthesis were included. Gait patterns were examined for symmetry, and performance was assessed using the six-minute walk test and the timed "Up & Go" test. Magnetic resonance imaging was performed to detect signs of osteoarthritis in both hips. Mobility in everyday life and quality of life were assessed using questionnaires.

FINDINGS

There were no differences between the groups regarding the quality of life, daily mobility, and gait performance. The step width was significantly higher for the patients using socket-suspended prosthesis. The socket-suspended group showed a significant asymmetry regarding the step length. In the socket-suspended group, the prosthetic leg showed significantly higher cartilage abrasion than the contralateral leg did.

INTERPRETATION

Large differences in the measured outcomes in both groups illustrate the very different capabilities of the individual participants, which is apparently not primarily determined by the type of treatment. For patients who are satisfied with the socket treatment and perform well, bone-anchored prosthesis systems may not necessarily improve their functional capabilities and perceived quality of life.

Magnetic resonance imaging is able to detect patellofemoral focal cartilage injuries: a systematic review with meta-analysis

PURPOSE

The purpose of this study was to analyze the diagnostic accuracy of magnetic resonance imaging (MRI) to detect and grade the severity of patellofemoral (PF) cartilage injuries.

METHODS

A systematic review was conducted on PubMed, EMBASE and Cochrane Library databases (up to July 1st 2022) to search for studies that reported the diagnostic accuracy of MRI to detect and grade PF cartilage injuries as compared to diagnostic arthroscopy. Risk of bias was judged using the QUADAS-2 tool. Quantitative syntheses were performed to calculate the diagnostic accuracy metric-sensitivity, specificity, positive likelihood (LR+) and negative likelihood (LR-) ratios, diagnostic odds ratio (DOR)-and presented as median with 25% and 75% percentiles. The summary receiver operating characteristic (SROC) curves were also calculated. Diagnostic accuracy metrics were calculated for all PF cartilage injuries and then sub-grouped by patellar and trochlear lesions. Diagnostic accuracy was also calculated according to the grading of cartilage injuries.

RESULTS

Forty-five studies were included for qualitative analyses and forty studies were included for quantitative synthesis. A total of 3534 participants with a weighted mean age of 38.1 years were included. Diagnostic accuracy was generally high: sensitivity (0.8, 0.6-1.0), specificity (0.9, 0.8-1.0), LR+ (6.4, 3.1-15.3), LR- (0.3, 0.2-0.4) and DOR (21.3, 9.9-121.1). The area under the curve (AUC) of the SROC was 0.9. The diagnostic accuracy was slightly higher for patellar (sensitivity 0.8, specificity 0.8, LR+ 5.3, LR- 0.2, DOR 28.8) than for trochlear lesions (sensitivity 0.7, specificity 0.9, LR+ 5.5, LR- 0.4, DOR 14.3). The sensitivity was generally higher when grading advanced (vs. early or intermediate) cartilage injuries of the patella.

CONCLUSION

The MRI is able to diagnose PF cartilage injuries with reasonably high diagnostic accuracy (as compared to arthroscopy). Clinicians can rely on MRI to reliably diagnose PF cartilage injuries (with some limitations) which will play an important role in deciding for surgical or non-operative treatment.

LEVEL OF EVIDENCE

Level III.

Knee Cartilage Imaging

Articular cartilage injury and degeneration represent common causes of knee pain, which can be evaluated accurately and noninvasively using MRI. This review describes the structure of cartilage focusing on its histologic appearance to emphasize that structure will dictate patterns of tissue failure as well as MR appearance. In addition to identifying cartilage loss, MRI can demonstrate signal changes that correspond to intrinsic structural abnormalities which place the cartilage at risk for subsequent more serious injury or premature degeneration, allowing for earlier intervention and treatment of important causes of pain and morbidity.

Diagnostic Accuracy of Magnetic Resonance Images and Weight-Bearing Radiographs in Patients With Arthroscopic-Proven Medial Osteoarthritis of the Knee

Aims:

The aim of this study is to analyze the diagnostic value of weight-bearing radiographs, magnetic resonance images (MRI), and the combination of both in osteoarthritic knees when using arthroscopic findings as the “gold standard” to compare with.

Methods:

A total of 59 patients were studied because of chronic pain in 1 of their knees. Radiographs were classified according to Kellgren-Lawrence scale. Magnetic resonance images were classified according to Vallotton, and arthroscopic findings according to Outerbridge criteria.

Results:

Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were, respectively, 75.0%, 60.0%, 56.2%, 77.8%, and 66.1% for weight-bearing radiographs, and 70.8%, 88.6%, 81.0%, 81.6%, and 81.4% for MRI. Logistic regression analysis showed that a weight-bearing radiograph added to MRI offered no additional diagnostic value compared with MRI alone (P < .001).

Conclusions:

Magnetic resonance images presented higher specificity, positive and negative predictive values, and accuracy than weight-bearing radiographs for knee osteoarthritis. The combination of radiographs and MRI did not improve the diagnostic accuracy, compared with MRI alone.

[Effects of knee pain on postural control excluding the musculature of the craniomandibular system]

BACKGROUND

Knee pain can influence postural control in addition to changes in the anatomical structure of the knee joints.

OBJECTIVE

Because the influence of imbalances in the craniomandibular system has been proven multiple times, it is the aim of the present work to investigate the influence of various knee diagnoses on postural control excluding occlusal information by means of symmetrical packing using cotton rolls.

MATERIALS AND METHODS

One hundred and fifteen patients (74 male/41 female) aged 18-75 years with an average BMI of 25.13 ± 3.66 kg/m² took part in the study, among them 34 patients (26 male/8 female) with cruciate ligament injury, 26 (16 male/10 female) with meniscal lesions, 24 (13 male/11 female) with arthrosis, 21 (11 male/10 female) with patellar pain, and 10 (8 male/2 female) with other painful knee complaints. Postural control was increased using a force platform, the degree of severity of the disorder was recorded using the "Knee Injury and Osteoarthritis Outcome" questionnaire, and the occlusion packed on both sides with cotton rolls in the premolar area.

RESULTS

With increasing age, patients with knee arthrosis are more likely to stand on the hindfoot. In those with patellar disorder, increased weight-bearing on the forefoot correlates with increasing BMI. An increase in weight-bearing on the forefoot on the side of the uninjured knee in people with patellar disorder results not only in a reduction in quality of life but also level of daily activity.

DISCUSSION

The percentage weight-bearing on the zones of the feet differs in unilateral knee injuries (in particular, comparison of the side with the knee injury and the uninjured side). Age, BMI or gender are influencing factors. Because various correlations and/or effects in the subgroups of knee injuries are generated, an injury-specific analysis should be carried out. These effects are also identifiable in the subjective assessment of quality of life.

[Osteoarthritis classifications : Modification proposal for the criteria of Kellgren and Vallotton]

BACKGROUND

In imaging diagnostics, classification schemes are very common. As far as osteoarthritis is concerned, the Kellgren classification is the most popular. However, the Kellgren classification, which has been used for more than 50 years, is based on nonspecific criteria; thus, high interobserver variability has been reported. In addition, the Kellgren classifications have not been coordinated with magnetic resonance imaging (MRI)-based classification schemes, e.g., Vallotton.

AIM

In this paper, we present some modifications concerning the criteria for both the Kellgren classification and its comparison with the MRI-based Vallotton classification.

METHODS

The current surgical and imaging classifications and the precision of the nomenclature are analyzed. X‑ray and MRI findings are compared.

RESULTS

Suggestions for both a modification of the Kellgren classification as far as the criteria are concerned and a hierarchy (ranking) of X‑ray and MRI findings to make clinical decisions more valuable are proposed.

CONCLUSION

These proposed modifications (Kellgren and ranking) would be helpful for routine reporting and allow for better interobserver reliability, in particular for special reports (e.g. consultations, expert opinions, advanced diagnostics).

Image-Guided Chondrocyte Harvesting for Autologous Chondrocyte Implantation: Initial Feasibility Study with Human Cadaver and Pilot Clinical Experience

Background:

Autologous chondrocyte implantation (ACI), a promising modality for repairing full-thickness cartilage defects, requires 2 consecutive arthroscopic procedures for chondrocyte harvesting and implantation. In the present study, we assessed the feasibility and efficacy of image-guided chondrocyte harvesting as an alternative to arthroscopic biopsy.

Methods:

We induced full-thickness cartilage defects in 10 human cadaveric knees. Computed tomographic arthrography (CTA) was performed following the intra-articular administration of Omnipaque 350 to measure the diameters of the induced cartilage defects. Subsequently, 2 independent operators conducted CTA-guided chondrocyte harvesting (from the medial and lateral trochlear ridges) in each knee. The time for chondrocyte harvesting, accuracy (distance between the predefined target on CTA and the final insertion site of the needle), and number of needle readjustments were recorded. In the institutional review board-approved clinical study, informed consent was obtained and chondrocyte harvesting was performed both with use of a conventional arthroscopic biopsy method and with use of a needle through an arthroscopy access site in 10 subjects for whom ACI was indicated. The samples were processed and cultured blindly, and the quantity and quality of the samples were determined.

Results:

CTA measurements of full-thickness cartilage defects showed high to perfect absolute agreement and consistency when compared with direct measurements (overall interclass correlation coefficient, 0.933 to 0.983; p < 0.05). For both operators, image-guided chondrocyte harvesting from the lateral ridge was more accurate (p = 0.007 and 0.040) and faster (p = 0.056 and 0.014) in comparison with harvesting from the medial ridge. In the clinical study, no significant difference was observed for the growth index of samples between the needle-harvest and conventional methods (p = 0.897).

Conclusions:

CTA can be used for precise measurement of full-thickness cartilage defects. Image-guided chondrocyte harvesting is a viable alternative to traditional arthroscopic biopsy for ACI.

Clinical Relevance:

We recognize the current pivotal role of arthroscopic biopsy, as a part of ACI, for chondrocyte harvesting as well as for delineating the nature of the lesion. However, on the basis of our results, image-guided chondrocyte retrieval may obviate the need for arthroscopic biopsy in some patients in the future.

Lesion Size Measured on MRI Does Not Accurately Reflect Arthroscopic Measurement in Talar Osteochondral Lesions

Background:

Lesion size is a major determinant of treatment strategy for osteochondral lesions of the talus (OLTs). Although magnetic resonance imaging (MRI) is commonly used in the preoperative evaluation of OLTs, the reliability of the MRI measurement compared with the arthroscopic measurement is unknown.

Purpose:

To compare preoperative lesion size measured on MRI versus intraoperative lesion size measured during arthroscopy.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

We retrospectively reviewed a consecutive series of patients treated with bone marrow stimulation for OLTs. The diameter of the lesion was measured at its widest point in 2 planes, and MRI measurements were compared with those made during arthroscopy using a custom-made graduated probe.

Results:

A total of 39 patients with 45 OLTs were analyzed. Mean ± SD area measurements on MRI were significantly greater than the equivalent arthroscopic measurements (42.2 ± 30.5 vs 28.6 ± 23.1 mm², respectively; P = .03). Compared with the arthroscopic measurement, MRI overestimated OLT size in 53.3% (24/45) of ankles and underestimated OLT size in 24.4% (11/45). The mean MRI diameter measurement was significantly greater than the arthroscopic measurement in the coronal plane (MRI diameter vs arthroscopic measurement coronal plane, 6.1 ± 2.6 vs 4.9 ± 2.3 mm, P = .03; sagittal plane, 8.0 ± 3.6 vs 6.3 ± 3.6 mm, P = .05). Further, MRI overestimated coronal diameter in 48.9% (22/45) of ankles and underestimated in 26.7% (12/45) compared with the arthroscopic measurement. Similarly, sagittal plane MRI diameter measurements overestimated lesion size in 46.7% (21/45) of ankles and underestimated lesion size in 28.9% (13/45) compared with the arthroscopic findings.

Conclusion:

In a majority of lesions, MRI overestimated OLT area and diameter compared with arthroscopy. Surgeons should be aware of the discrepancies that can exist between MRI and arthroscopic measurements, as these data are important in making treatment decisions and educating patients.

The frequency of cartilage lesions in non-injured knees with symptomatic meniscus tears: results from an arthroscopic and NIR- (near-infrared) spectroscopic investigation

INTRODUCTION

Are symptomatic tear injuries to the menisci of the knee frequently or always associated with cartilage damage to the corresponding articular surfaces and other joint surfaces, respectively?

METHODS

A total of 137 patients (medial n = 127; lateral n = 10) underwent a meniscus resection. These patients showed no signs of a clear radiographic arthrosis and no MRI-detectable cartilage lesions > grade II. Traumatic injury was ruled out with a thorough medical history. The indication for operation was made exclusively on the basis of distinct, clinically apparent meniscus signs. In addition to the ICRS classification, all articular surfaces were examined spectroscopically (NIRS, near-infrared spectroscopy).

RESULTS

In 76.6% (n = 105) of all knees examined, clear cartilage damage (ICRS-grade III/IV) was found. For 43.8%, these were in the area of the patella, while for 34.3% they were in the area of the medial femur, and for 17.5%, in the area of the medial tibial plateau. More rarely, this damage was localized to the area of the trochlea (8.8%) or the lateral joint compartment (femoral 2.2%, tibial 15.3%). There were no significant differences between patients with medial or lateral meniscus lesions with respect to the distribution pattern of the joint injuries. During spectroscopic examination, pathological values were demonstrated (objective evidence of cartilage degeneration) in at least one of the examined articular surfaces (media n = 6, range 1-6).

CONCLUSION

Through our investigations, a high, if not complete, concomitance of degenerative cartilage lesions and degenerative meniscus damage was demonstrated. From this it can be concluded that the entity of "isolated degenerative meniscus damage" clearly does not exist in practice. It is therefore highly probable that degenerative meniscus lesions, as a part of general joint degeneration, are to be interpreted in the context of the development of arthrosis. The practical consequences still are unclear. Patients after partial meniscectomy need a longer follow-up to detect potential cartilage lesions as well as an OA progression.

Lesion Size Is a Predictor of Clinical Outcomes After Bone Marrow Stimulation for Osteochondral Lesions of the Talus: A Systematic Review

BACKGROUND

The critical lesion size treated with bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLTs) has been 150 mm² in area or 15 mm in diameter. However, recent investigations have failed to detect a significant correlation between the lesion size and clinical outcomes after BMS for OLTs.

PURPOSE

To systematically review clinical studies reporting both the lesion size and clinical outcomes after BMS for OLTs.

STUDY DESIGN

Systematic review.

METHODS

A systematic search of the MEDLINE and EMBASE databases was performed in March 2015 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies were evaluated with regard to the level of evidence (LOE), quality of evidence (QOE), lesion size, and clinical outcomes.

RESULTS

Twenty-five studies with 1868 ankles were included; 88% were either LOE 3 or 4, and 96% did not have good QOE. The mean area was 103.8 ± 10.2 mm² in 20 studies, and the mean diameter was 10.0 ± 3.2 mm in 5 studies. The mean American Orthopaedic Foot and Ankle Society score improved from 62.4 ± 7.9 preoperatively to 83.9 ± 9.2 at a mean 54.1-month follow-up in 14 studies reporting both preoperative and postoperative scores with a mean follow-up of more than 2 years. A significant correlation was found in 3 studies, with a mean lesion area of 107.4 ± 10.4 mm², while none was reported in 8 studies, with a mean lesion area of 85.3 ± 9.2 mm². The lesion diameter significantly correlated with clinical outcomes in 2 studies (mean diameter, 10.2 ± 3.2 mm), whereas none was found in 2 studies (mean diameter, 8.8 ± 0.0 mm). However, the reported lesion size measurement method and evaluation method of clinical outcomes widely varied among the studies.

CONCLUSION

An assessment of the currently available data does suggest that BMS may best be reserved for OLT sizes less than 107.4 mm² in area and/or 10.2 mm in diameter. Future development in legitimate prognostic size guidelines based on high-quality evidence that correlate with outcomes will surely provide patients with the best potential for successful long-term outcomes.

Indications requiring preoperative magnetic resonance imaging before knee arthroscopy

INTRODUCTION

Knee arthroscopy knee is gold standard in diagnosis and simultaneous treatment of knee disorders. But most patients undergo magnetic resonance imaging (MRI) before arthroscopy, although MRI results are not always consistent with arthroscopic findings. This raises the question in which suspected diagnoses MRI really has influence on diagnosis and consecutive surgical therapy.

MATERIAL AND METHODS

Preoperative MRI of 330 patients with knee disorders were compared with arthroscopic findings. The MRI were performed by 23 radiologists without specialization in musculoskeletal diagnostics. Specificity, sensitivity, negative/positive predictive value and accuracy of MRI were calculated in comparison to arthroscopic findings.

RESULTS

We found sensitivity/specificity of 58%/93% for anterior horn, 94%/46% for posterior horn of medial meniscus and 71%/81% for anterior and 62%/82% for posterior horn of lateral meniscus. Related to anterior cruciate ligament injuries we showed sensitivity/specificity of 82%/91% for grade 0 + I and 72%/96% for grade II + III. For Cartilage damage sensitivity/specificity of 98%/7% for grade I-, 89%/29% for grade II-, 96%/38% for grade III- and 96%/69% for grade IV-lesions were revealed.

CONCLUSIONS

The MRI should not be used as routine diagnostic tool for knee pain. No relevant information for meniscal lesions and anterior cruciate ligament ruptures has been gained with MRI from non-specialized outside imaging centres. The MRI should not be used as routine diagnostic tool for knee pain. No relevant information for meniscal lesions and anterior cruciate ligament ruptures has been gained with MRI from non-specialized outside imaging centres.

Imaging of articular cartilage

We tried to review the role of magnetic resonance imaging (MRI) in understanding microscopic and morphologic structure of the articular cartilage. The optimal protocols and available spin-echo sequences in present day practice are reviewed in context of common pathologies of articular cartilage. The future trends of articular cartilage imaging have been discussed with their appropriateness. In diarthrodial joints of the body, articular cartilage is functionally very important. It is frequently exposed to trauma, degeneration, and repetitive wear and tear. MRI has played a vital role in evaluation of articular cartilage. With the availability of advanced repair surgeries for cartilage lesions, there has been an increased demand for improved cartilage imaging techniques. Recent advances in imaging strategies for native and postoperative articular cartilage open up an entirely new approach in management of cartilage-related pathologies.

Comparison of 1.5- and 3-T MR imaging for evaluating the articular cartilage of the knee

PURPOSE

The aim of this prospective study was to compare routine MRI scans of the knee at 1.5 and 3 T obtained in the same individuals in terms of their performance in the diagnosis of cartilage lesions.

METHODS

One hundred patients underwent MRI of the knee at 1.5 and 3 T and subsequent knee arthroscopy. All MR examinations consisted of multiplanar 2D turbo spin-echo sequences. Three radiologists independently graded all articular surfaces of the knee joint seen at MRI. With arthroscopy as the reference standard, the sensitivity, specificity, and accuracy of 1.5- and 3-T MRI for detecting cartilage lesions and the proportion of correctly graded cartilage lesions within the knee joint were determined and compared using resampling statistics.

RESULTS

For all readers and surfaces combined, the respective sensitivity, specificity, and accuracy for detecting all grades of cartilage lesions in the knee joint using MRI were 60, 96, and 87% at 1.5 T and 69, 96, and 90% at 3 T. There was a statistically significant improvement in sensitivity (p < 0.05), but not specificity or accuracy (n.s.) for the detection of cartilage lesions at 3 T. There was also a statistically significant (p < 0.05) improvement in the proportion of correctly graded cartilage lesions at 3 T as compared to 1.5 T.

CONCLUSION

A 3-T MR protocol significantly improves diagnostic performance for the purpose of detecting cartilage lesions within the knee joint, when compared with a similar protocol performed at 1.5 T.

LEVEL OF EVIDENCE

III.

Accuracy of magnetic resonance imaging, magnetic resonance arthrography and computed tomography for the detection of chondral lesions of the knee

PURPOSE

To assess the diagnostic test accuracy of magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA) and computed tomography arthrography (CTA) for the detection of chondral lesions of the patellofemoral and tibiofemoral joints.

METHODS

A review of published and unpublished literature sources was conducted on 22nd September 2011. All studies assessing the diagnostic test accuracy (sensitivity/specificity) of MRI or MRA or CTA for the assessment of adults with chondral (cartilage) lesions of the knee (tibiofemoral/patellofemoral joints) with surgical comparison (arthroscopic or open) as the reference test were included. Data were analysed through meta-analysis.

RESULTS

Twenty-seven studies assessing 2,592 knees from 2,509 patients were included. The findings indicated that whilst presenting a high specificity (0.95-0.99), the sensitivity of MRA, MRI and CTA ranged from 0.70 to 0.80. MRA was superior to MRI and CTA for the detection of patellofemoral joint chondral lesions and that higher field-strength MRI scanner and grade four lesions were more accurately detected compared with lower field-strength and grade one lesions. There appeared no substantial difference in diagnostic accuracy between the interpretation from musculoskeletal and general radiologists when undertaking an MRI review of tibiofemoral and patellofemoral chondral lesions.

CONCLUSIONS

Specialist radiological imaging is specific for cartilage disease in the knee but has poorer sensitivity to determine the therapeutic options in this population. Due to this limitation, there remains little indication to replace the 'gold-standard' arthroscopic investigation with MRI, MRA or CTA for the assessment of adults with chondral lesions of the knee.

LEVEL OF EVIDENCE

II.

MRI after unicondylar knee arthroplasty: the preserved compartments

PURPOSE

The aim of this study was to assess the reproducibility of using magnetic resonance imaging (MRI) to analyze the preserved anatomic knee compartments following unicondylar knee arthroplasty (UKA) with zirconium femoral components. It was hypothesized that evaluation of the cartilage, ligaments, meniscus, and tendons would result in a high rate of inter-observer reliability.

SCOPE

Ten patients underwent MRI of the knee tailored to reduce metallic artifact following medial UKA with zirconium femoral implants. Cartilage, external meniscus, collateral and cruciate ligaments, the quadriceps and patellar tendons, and the presence of joint effusion were evaluated by two independent investigators. The reviewers provided degrees of confidence with their evaluation of each parameter through the use of a five-point scale. Inter-observer agreement was calculated and inter-observer reliability was determined by use of Cohen's Kappa. Artifacts originating from the implants were rarely observed. There was excellent inter-observer reliability (i.e., high Cohen's Kappa) for all assessed structures, and a high level of observer confidence for the evaluation of the cartilage, meniscus, tendons, ligaments, and joint effusion.

CONCLUSION

In this study tailored MRI allows for reproducible analysis of the preserved knee joint compartment after UKA for zirconium implants. This technique might prove helpful in the assessment of painful knee joints after UKA with other metallic materials as new MRI software programs, which suppress metal artifacts, are developed.

Sensitivity of magnetic resonance imaging for detection of patellofemoral articular cartilage defects

PURPOSE

Chondral defects within the patellofemoral compartment are common and lack the ability to heal on their own. Early detection of these lesions with a noninvasive modality would be beneficial in delaying or preventing their possible progression to osteoarthritis. We hypothesized that magnetic resonance imaging (MRI) is a sensitive, specific, and accurate imaging modality for the detection of patellofemoral chondral defects with substantial interobserver reliability and that MRI has a higher sensitivity, specificity, and accuracy for detecting patellar defects than trochlear defects.

METHODS

A systematic review of multiple medical databases was performed by use of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol. Analysis of studies that reported diagnostic performance of MRI in the assessment of patellofemoral chondral defects (patella and trochlea), using arthroscopy as the reference gold standard, was performed. Sensitivity, specificity, accuracy, and interobserver reliability were reported. Significant heterogeneity across studies precluded meta-analysis.

RESULTS

MRI was more sensitive in detection of patellar (87%) versus trochlear (72%) defects. MRI was similarly specific for patellar (86%) and trochlear (89%) defects. MRI was similarly accurate for patellar (84%) and trochlear (83%) defects. Interobserver agreement was substantial to almost perfect for both patellar and trochlear defects.

CONCLUSIONS

MRI is a highly sensitive, specific, and accurate noninvasive diagnostic modality for the detection of chondral defects in the patellofemoral compartment of the knee, using arthroscopy as the reference gold standard. Although there was wide variability in the statistical parameters assessed, MRI was more sensitive for detection of patellar versus trochlear defects and similarly specific and accurate for patellar and trochlear defects. Interobserver reliability is substantial to near perfect in the assessment of these lesions, without a significant difference between patellar and trochlear defects.

CLINICAL RELEVANCE

Use of MRI may allow early detection of chondral defects within the patellofemoral compartment, enabling clinicians to adopt strategies to delay or prevent progression to osteoarthritis.

LEVEL OF EVIDENCE

Level III, systematic review of Level I, II, and III studies.

Correlation of preoperative MRI and MRA with arthroscopically proven articular cartilage lesions of the elbow

OBJECTIVE

The purpose of this study was to evaluate the usefulness of magnetic resonance imaging (MRI) in detecting elbow articular cartilage injuries through comparison of preoperative MRI and magnetic resonance arthrography (MRA) with arthroscopic findings.

DESIGN

Retrospective case analysis.

SETTING

Tertiary care orthopedic private practice.

PATIENTS

Consecutive series of 31 patients presenting with elbow pain and diagnosed at arthroscopy with articular cartilage defects of the elbow. All patients had a preoperative MRI or MRA using a 1.5 T magnet.

INTERVENTIONS

Each patient had a systematic elbow arthroscopy, with careful inspection and recording of chondral injuries in 4 anatomical regions: capitellum, radius, trochlea, and ulna. Each MRI/MRA was then independently reviewed by 2 radiologists blinded to the arthroscopic findings.

MAIN OUTCOME MEASURES

The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were calculated for MRI and MRI compared with arthroscopy as the gold standard, for each of the anatomical regions.

RESULTS

The accuracy of MRI was 45% for chondral injuries of the radius, 65% for the capitellum, 20% for the ulna, and 30% for the trochlea. The accuracy of MRA was 45% for chondral injuries of the radius, 64% for the capitellum, 18% for the ulna, and 27% for the trochlea.

CONCLUSION

We conclude that the ability of MRI and MRA using a 1.5 T magnet to detect articular cartilage lesions is limited. Neither MRI nor MRA demonstrates the intraarticular surface as accurately as direct visualization with the arthroscopy. This may be improved with the use of 3 T MRI.

CLINICAL RELEVANCE

This study demonstrates that MRI and MRA with a 1.5 T magnet, as used in community practice, have limited ability to detect cartilage lesions of the elbow.

Advanced MRI of articular cartilage

Musculoskeletal MRI is advancing rapidly, with innovative technology and significant potential for immediate clinical impact. In particular, cartilage imaging has become a topic of increasing interest as our aging population develops diseases such as osteoarthritis. Advances in MRI hardware and software have led to increased image quality and tissue contrast. Additional developments have allowed the assessment of cartilage macromolecular content, which may be crucial to the early detection of musculoskeletal diseases. This comprehensive article considers current morphological and physiological cartilage imaging techniques, their clinical applications, and their potential to contribute to future improvements in the imaging of cartilage.

The clinical utility and diagnostic performance of magnetic resonance imaging for identification of early and advanced knee osteoarthritis: a systematic review

BACKGROUND

Current diagnostic strategies for detection of structural articular cartilage abnormalities, the earliest structural signs of osteoarthritis, often do not capture the condition until it is too far advanced for the most potential benefit of noninvasive interventions.

PURPOSE

To systematically review the literature relative to the following questions: (1) Is magnetic resonance imaging (MRI) a valid, sensitive, specific, accurate, and reliable instrument to identify knee articular cartilage abnormalities compared with arthroscopy? (2) Is MRI a sensitive tool that can be utilized to identify early cartilage degeneration?

STUDY DESIGN

Systematic review.

METHODS

A systematic search was performed in November 2010 using PubMed MEDLINE (from 1966), CINAHL (from 1982), SPORTDiscus (from 1985), SCOPUS (from 1996), and EMBASE (from 1974) databases.

RESULTS

Fourteen level I and 13 level II studies were identified that met inclusion criteria and provided information related to diagnostic performance of MRI compared with arthroscopic evaluation. The diagnostic performance of MRI demonstrated a large range of sensitivities, specificities, and accuracies. The sensitivity for identifying articular cartilage abnormalities in the knee joint was reported between 26% and 96%. Specificity and accuracy were reported between 50% and 100% and between 49% and 94%, respectively. The sensitivity, specificity, and accuracy for identifying early osteoarthritis were reported between 0% and 86%, 48% and 95%, and 5% and 94%, respectively. As a result of inconsistencies between imaging techniques and methodological shortcomings of many of the studies, a meta-analysis was not performed, and it was difficult to fully synthesize the information to state firm conclusions about the diagnostic performance of MRI.

CONCLUSION

There is evidence in some MRI protocols that MRI is a relatively valid, sensitive, specific, accurate, and reliable clinical tool for identifying articular cartilage degeneration. Because of heterogeneity of MRI sequences, it is not possible to make definitive conclusions regarding its global clinical utility for guiding diagnosis and treatment strategies.

CLINICAL RELEVANCE

Traumatic sports injuries to the knee may be significant precursor events to early onset of posttraumatic osteoarthritis. Magnetic resonance imaging may aid in early identification of structural injuries to articular cartilage as evidenced by articular cartilage degeneration grading.

Articular cartilage in the knee: current MR imaging techniques and applications in clinical practice and research

Magnetic resonance (MR) imaging is the most important imaging modality for the evaluation of traumatic or degenerative cartilaginous lesions in the knee. It is a powerful noninvasive tool for detecting such lesions and monitoring the effects of pharmacologic and surgical therapy. The specific MR imaging techniques used for these purposes can be divided into two broad categories according to their usefulness for morphologic or compositional evaluation. To assess the structure of knee cartilage, standard spin-echo (SE) and gradient-recalled echo (GRE) sequences, fast SE sequences, and three-dimensional SE and GRE sequences are available. These techniques allow the detection of morphologic defects in the articular cartilage of the knee and are commonly used in research for semiquantitative and quantitative assessments of cartilage. To evaluate the collagen network and proteoglycan content in the knee cartilage matrix, compositional assessment techniques such as T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage (or dGEMRIC), T1ρ imaging, sodium imaging, and diffusion-weighted imaging are available. These techniques may be used in various combinations and at various magnetic field strengths in clinical and research settings to improve the characterization of changes in cartilage.

Four-year results from a randomized controlled study of knee chondroplasty with concomitant medial meniscectomy: mechanical debridement versus radiofrequency chondroplasty

PURPOSE

This randomized study was undertaken to compare the effectiveness of simple mechanical debridement and 50 degrees C controlled bipolar chondroplasty.

METHODS

A total of 60 patients who had a grade III articular cartilage defect of the medial femoral condyle were included. After randomization, 30 patients underwent simple debridement of articular cartilage defects, which was performed with a mechanical shaver (mechanical shaver debridement [MSD] group). The remaining patients underwent thermal chondroplasty, which was performed with a temperature-controlled bipolar device with a constant thermo-application of a maximum of 50 degrees C (radiofrequency-based chondroplasty [RFC] group). All patients underwent partial (n = 41) or subtotal (n = 19) meniscectomy. Follow-up was undertaken 4 years postoperatively.

RESULTS

No significant differences between the preoperative findings for the 2 groups were observed. One patient from the MSD group had died, and one female patient in the RFC group was lost to follow-up. A total of 18 patients had undergone revision operations for persistent knee problems: in the MSD group, there were 8 endoprostheses, 4 osteotomies, and 2 revision arthroscopies, whereas in the RFC group, there was 1 replacement, 2 osteotomies, and 1 revision arthroscopy with subtotal medial meniscectomy. The proportion of revisions was significantly higher in the MSD group (P = .006). These patients were excluded from the evaluation. The remaining 40 patients from both groups benefited from the operation. The preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) was 11.3 points in the MSD group and 15.5 points in the RFC group (P = .279). Patients from the MSD group had a KOOS of 53.2 points at the time of follow-up. In the RFC group the KOOS (71.8 points) was significantly higher (P < .001).

CONCLUSIONS

Compared with classical mechanical debridement, bipolar radiofrequency currently appears to be the superior method for achieving a good midterm result.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

How valid is the arthroscopic diagnosis of cartilage lesions? Results of an opinion survey among highly experienced arthroscopic surgeons

AIM

In general, arthroscopy is considered the "gold standard" for the evaluation of cartilage lesions. In this multicenter survey, we ascertained the general opinion of surgeons regarding arthroscopic cartilage diagnoses.

METHOD

A total of 301 highly experienced arthroscopists (instructors of the AGA, the German-speaking society of arthroscopy) were contacted in writing with a request to complete the survey.

RESULTS

The data from 105 respondents (34.8% of those contacted) were used for the investigation. In the grading of the cartilage lesions, the Outerbridge classification was most frequently used (n = 87), followed by the ICRS protocol (n = 8) and the Insall score (n = 3). The majority (61%) of the arthroscopic surgeons felt that differentiation between healthy cartilage and low-grade cartilage lesions was simple. For differentiation between grade I and grade II lesions, and for differentiation between grade II and grade III lesions, 41.9 and 51.4%, respectively, thought that there was a "need for improvement". In the case of grade IV lesions, 70.5% of the surgeons thought that the diagnosis was valid. The respondents also judged the utility of incorporating objective measurements (e.g., intraoperative biomechanical tests): 13.3% (n = 14) responded that such measurements would be "very useful" and 61.9% (n = 65) responded that they would be "somewhat useful".

CONCLUSIONS

Among surgeons, arthroscopy was not perceived to be as reliable as a "gold standard" for the diagnosis of cartilage lesions. The majority of experienced arthroscopists felt unsure of the results in general, or at least in some cases. A universal and definitive grading system for lesions appears to be needed. For questionable cases, measurement devices are needed for objective cartilage grading.

The accuracy of magnetic resonance imaging scanning and its influence on management decisions in knee surgery

PURPOSE

The purpose of our study was to evaluate the impact of preoperative magnetic resonance imaging (MRI) assessment of articular knee pathology on the clinical management of patients presenting with joint line pain.

METHODS

A preliminary study on 100 patients was performed to assess the accuracy of specific MRI sequences, using arthroscopy as a gold standard. Six hundred and eighteen consecutive patients with knee symptoms presenting to 2 specialist knee surgeons were then recruited. A clinical diagnosis of an arthroscopically treatable lesion was made in all cases. Clinical assessment data were correlated to subsequent MRI findings, recording any discrepancy and in particular whether or not MRI findings influenced management decisions.

RESULTS

In the preliminary study, MRI sequences had an overall sensitivity of 83.2% and a specificity of 94.3% for the detection of chondral lesions. However, when considering arthroscopic grade III and IV lesions, MRI sensitivity and specificity were improved to 84.5% and 97.1%. In the second phase of the study, 141 (22.8%) of the 618 patients presenting with knee symptoms had an altered clinical management subsequent to MRI. The presence of unexpected chondral lesions was found in 77 of these patients. Conversely, 22 patients with clinical symptoms suspicious for simple chondral degeneration had unstable meniscal tears.

CONCLUSIONS

We suggest that preoperative MRI scanning identifies a group of patients who have more advanced degenerative joint disease than the clinical assessment and the plain radiographs suggest. This would expedite definitive surgery in patients with advanced osteoarthritis on MRI scans.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied gold standard.

One screening magnetic resonance imaging sequence in evaluation of chondral and meniscal lesions of the knee - a pilot study

This prospective study aimed to evaluate if chondral and meniscal lesions in symptomatic knees of osteoarthritis patients can be reliably identified using only one sagittal dual-echo MRI (Magnetic Resonance Imaging) sequence. MRI was performed on 13 patients after knee arthroscopy due to knee pain and clinically suspected osteoarthritis using a 1.5-Tesla scanner with knee coil and a sagittal dual-echo turbo spin-echo PD (Proton Density)- and T2-weighted sequence. The MRI and arthroscopic findings were then compared. Of 65 articular surfaces, 47 were damaged. For articular cartilage lesions, the overall sensitivity of MRI was 46.8%, specificity 72.2%, and diagnostic accuracy 53.9%, and for meniscal ruptures 81.2%, 66.7%, and 73.1%, respectively. The present study showed that the reliability of screening MRI of knees using only one sagittal dual-echo sequence does not suffice for diagnosis of chondral or meniscal lesions, and should therefore not replace routine knee MRI or diagnostic arthroscopy.

[Evaluation of cartilage defects in the knee: validity of clinical, magnetic-resonance-imaging and radiological findings compared with arthroscopy]

BACKGROUND

The study was aimed to evaluate the validity of clinical, radiological and MRI examination for cartilage defects of the knee compared with arthroscopic finding.

METHODS

Seven-hundred seventy-two patients who were suffering from knee pain over more than 3 months were evaluated clinical (grinding-sign) and with radiography and magnetic resonance imaging (MRI) and subsequent arthroscopy.

RESULTS

The grinding sign had a sensitivity of 0.39. The association of a positive grinding test with high grade cartilage defects was significant (p<0.000). In 97.4% an intact chondral surface correlated with a normal radiological finding. Subchondral sclerosis, exophytes and a joint space narrowing was significantly associated with high grade cartilage defects (p<0.000). The accuracy of MRI was 59.5%. The MRI resulted in an overestimation in 36.6% and an underestimation in 3.9%. False-positive results were significant more often assessed in low-grade cartilage defects (p<0.000).

CONCLUSIONS

Clinical signs, x-ray imaging and MRI correlate with arthroscopic findings in cases of deep cartilage lesions. In intact or low-grade degenerated cartilage often results an overestimating of these findings.

Near-infrared (NIR) spectroscopy. A new method for arthroscopic evaluation of low grade degenerated cartilage lesions. Results of a pilot study

BACKGROUND

Arthroscopy is a highly sensitive method of evaluating high-grade cartilage lesions but the detection of low-grade lesions is often is unreliable. Objective measurements are required. A novel NIRS (near-infrared-spectroscopy) device for detection of low-grade cartilage defects was evaluated in a preliminary clinical study.

METHODS

In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol. With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy.

RESULTS

The mean ratio of 2 NIR absorption bands of intact cartilage 3.8 (range 2.3 to 8.7).was significantly lower than that of cartilage with grade 1 lesions (12.8, range 4.8 to 19.6) and grade 2 lesions (13.4, range 10.4 to 15.4).No differences were observed between grade 1 and grade 2 lesions.

CONCLUSION

NIRS can be used to distinguish between ICRS grade 1 lesions and healthy cartilage during arthroscopic surgeries. The results of this clinical study demonstrate the potential of NIRS to objectify classical arthroscopic grading systems.

Sensitivity of routine 1.0-Tesla magnetic resonance imaging versus arthroscopy as gold standard in fresh traumatic chondral lesions of the knee in young adults

PURPOSE

The purpose of this study was to evaluate the sensitivity, specificity, and accuracy of routine 1.0-Tesla magnetic resonance imaging (MRI) versus arthroscopy in detecting fresh traumatic chondral lesions of the knee.

METHODS

Over a period of 6 years, 578 consecutive military personnel underwent MRI before arthroscopy of the knee. Of these, 32 patients with arthroscopically proven fresh traumatic chondral lesions of the knee were chosen for further analysis. A supplementary condition was that arthroscopy was performed no later than 6 weeks after the onset of trauma. The original MRIs and hospital records were re-evaluated and the chondral lesions were graded and compared with arthroscopic findings. The arthroscopic results served as the gold standard when the sensitivity, specificity, and accuracy of MRI were calculated.

RESULTS

The age of the patients ranged from 19 to 21 years (mean, 19.6 years). MRI detected cartilage defects with a sensitivity of 36% (95% confidence interval [CI], 23% to 50%), specificity of 91% (95% CI, 85% to 95%), and diagnostic accuracy of 78% (95% CI, 72% to 83%). MRI results were affected by the grade of the chondral lesions.

CONCLUSIONS

This study shows that routine 1.0-T MRI is not sensitive but is specific and somewhat accurate in detecting fresh traumatic articular cartilage lesions. The hypothesis of this study was that 1.0-T MRI could replace diagnostic arthroscopy in the diagnosis of fresh traumatic chondral lesions. Our results fail to support this hypothesis because of the poor sensitivity obtained with MRI.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria.

3T MR Imaging of the Musculoskeletal System (Part II): Clinical Applications

The gain in SNR that is afforded by 3T MR imaging systems has tremendous clinical applications in the musculoskeletal system. The potential for demonstrating and enhancing the visibility of normal osseous, tendinous, cartilaginous, and ligamentous structures is exciting. Furthermore, harnessing this added signal to increase spatial resolution may improve our diagnostic abilities in various joints dramatically. Radiologists have enjoyed great success in assessing joint disease with current MR imaging field strengths; however, many intrinsic joint structures remain poorly evaluated, which leads to a golden opportunity for 3T MR imaging. The articular cartilage of the knee, the glenoid labrum of the shoulder, the intrinsic ligaments and TFC of the wrist, the collateral ligaments of the elbow, the labrum and articular cartilage of the hip, and the collateral ligaments of the ankle have been evaluated suboptimally on 1 .5T systems using routine nonarthrographic MR images. Because of the enhanced SNR, the higher spatial resolution, and the greater CNR of intrinsic joint structures at higher field strengths, 3T MR imaging has the potential to improve diagnostic abilities in the musculoskeletal system vastly, which translates into better patient care and management. The author's 2 years of clinical experience with musculoskeletal MR imaging on 3T systems has met and exceeded his expectations, and has bolstered the confidence of his orthopedic surgeons in his diagnoses. As coil technology advances and as the use of parallel imaging becomes more available in the extremities, the author expects to see even more dramatic improvements in image quality.

Cartilage MR imaging at 3.0 versus that at 1.5 T: preliminary results in a porcine model

PURPOSE

To compare 1.5- and 3.0-T magnetic resonance (MR) images of porcine knee specimens containing artificial cartilage lesions in terms of accuracy of lesion depiction, image quality, and signal-to-noise ratio (SNR).

MATERIALS AND METHODS

This Health Insurance Portability and Accountability Act-compliant study had institutional review board approval, and informed consent was obtained from the human volunteers. Two fat-saturated cartilage MR imaging sequences (an intermediate-weighted fast spin-echo [SE] sequence and a spoiled gradient-echo [GRE] sequence) were optimized for imaging at 3.0 T in two human volunteers and then used to image 10 porcine knees in which 29 artificial cartilage lesions had been created. Corresponding sequences were used at 1.5 T for all specimens. Images were assessed by two radiologists in consensus, and diagnostic performance in lesion depiction was determined by using macroscopic findings in specimen slices as a reference standard. SNRs were also calculated. For statistical analysis, the McNemar test of discordant pairs was used with a level of significance of P < .05.

RESULTS

The best diagnostic performance for both the intermediate-weighted fast SE and the spoiled GRE sequences was achieved at 3.0 T. With use of corresponding fat-saturated intermediate-weighted fast SE sequences with an identical acquisition time (9 minutes 44 seconds), 26 (90%) of 29 lesions were detected at 3.0 T, while 18 (62%) were detected at 1.5 T. With use of fat-saturated spoiled GRE sequences, 24 (83%) of 29 lesions were detected at 3.0 T (acquisition time, 8 minutes 48 seconds), and 23 (79%) lesions were detected at 1.5 T (acquisition time, 11 minutes 14 seconds). The rate of correct lesion grade assessment was 65% (17 of 26 lesions) at 3.0 T and 61% (11 of 18 lesions) at 1.5 T with the intermediate-weighted fast SE sequences and 83% (20 of 24 lesions) at 3.0 T and 70% (16 of 23 lesions) at 1.5 T with the spoiled GRE sequences. Both subjective evaluation of image quality and SNR values were significantly higher at 3.0 T (P < .05).

CONCLUSION

In this animal model, MR imaging at 3.0 T increased the accuracy of cartilage lesion assessment when compared with imaging at 1.5 T. Image quality and SNR were highest at 3.0 T.

[Imaging and preoperative planning of osteotomy of tibial head osteotomy]

Valgus-producing osteotomy of the proximal tibia is a well-established treatment for medial femorotibial osteoarthritis in the varus knee. The ideal patient is active, under 55 years of age, has a stable varus deformity of less than 10 degrees, a good bone stock, and an osteoarthritis stage that is restricted to the medial compartment of the knee. Coventry reported a failure rate in proximal tibial osteotomy to be significantly higher when the postoperative alignment was less than 8 degrees of anatomical valgus. Hernigou noted better clinical long-term results in cases with a precise correction of malalignment. There are different preoperative planning methods varying between simple estimates of correction angles and specific radiographic planning tools. The reproducibility of operative outcome with regard to a predictable anatomic alignment and functional recovery must have high priority. This chapter deals with different preoperative planning methods to improve the reliability of surgical results after tibial osteotomy.

Single photon emission computed tomography scanning in the diagnosis of knee pathology

PURPOSE

To evaluate the role of single photon emission computed tomography (SPECT) bone scan for the diagnosis of knee lesions in routine clinical practice.

METHODS

40 consecutive case records were examined in patients who underwent a SPECT scan prior to knee arthroscopy in routine clinical practice. The accuracy of clinical examination, SPECT scan results, and arthroscopic findings (as the gold standard) in diagnosing knee lesions were compared.

RESULTS

The sensitivity of SPECT scans in detecting medial meniscal, lateral meniscal, anterior cruciate ligament lesions, osteochondral defects, and chondromalacia patellae was 77%, 14%, 33%, 50%, and 74%, respectively. The specificities for the same structural lesions were high at 89%, 94%, 97%, 94%, and 69%, respectively.

CONCLUSION

SPECT bone scan appears to be useful in the diagnosis of knee pathology in routine practice and in selecting patients for arthroscopy, especially most useful for the diagnosis of medial meniscal tears.

What's new in cartilage?

Magnetic resonance (MR) imaging of articular cartilage is important in evaluation of new surgical and pharmacologic treatments for cartilage damage. Many techniques exist for MR imaging of articular cartilage. Standard techniques for morphologic imaging of cartilage include fast spin-echo and spoiled gradient-echo imaging. These methods provide high-resolution morphologic images of cartilage but are time-consuming in the clinical setting. New methods for faster or higher-resolution morphologic imaging include techniques based on steady-state free precession imaging. These fast techniques will allow detailed evaluation of cartilage in the routine clinical setting. There are also several MR imaging methods that may provide information about the structure and physiology of cartilage. Physiologic imaging may allow detailed evaluation of the glycosaminoglycan matrix or collagen network of articular cartilage and may be the most sensitive method for detection of early changes. With the development of new therapies for osteoarthritis and cartilage injury, MR imaging of articular cartilage is of increasing clinical importance. MR imaging will play an important role in evaluation of the effectiveness of these therapies.

Imaging in sports-medicine--knee

Since the last decade, the introduction of Magnetic Resonance Imaging has provided a powerful new tool for the clinician to diagnose sports-related knee injuries. The main objective of this paper is to familiarise the relevant specialists with the proven clinical indications and semiology of MRI of the knee. At the present time, the knee joint is the area in which the advantages of MRI are most spectacularly apparent. The MR appearances of meniscal tears in particular, are first discussed in detail, referring to recent literature and personal experience based on more than ten thousands MR examinations of traumatic knees. Also the mechanisms of injuries and the most commonly involved sports are described. The precise types of meniscal lesions, as visualised at arthroscopy, are abundantly illustrated on MR images: e.g., bucket-handle, radial and horizontal cleavage tears, meniscocapsular separations, discoid menisci and meniscal cysts. We discuss the numerous pitfalls due to neighbouring anatomical structures as well as non clinically or surgically significant intrameniscal hypersignals in athletes. Towards other imaging techniques, MRI is particularly suited for the diagnosis of ligamentous injuries, especially the cruciate ligaments. We develop the currently used direct and indirect signs of rupture, the diagnostic difficulties related to the age of trauma and the detection of associated lesions. Sport-induced tendinous and bursal pathology is another interesting indication of MRI, not only lesions of the more superficial extensor tendons but also the pes anserinus or hamstring tendons. We finally treat the recent developments of MRI in assessment of cartilage, subchondral and medullary bone disorders of traumatic or microtraumatic origin.

Current status of imaging procedures in the diagnosis, prognosis and monitoring of osteoarthritis

X-ray, magnetic resonance imaging (MRI) and arthroscopy are the methods most widely used to assess the status of osteoarthritic joints. How do these methods compare? As diagnostic tools, what is the relative sensitivity of X-ray versus MRI, arthroscopy versus MRI and arthroscopy versus X-ray? Which imaging modalities can be used for predicting progression? Scintigraphy and MRI can assess the degree of cellular activity in the tissues of a joint, which may help in prognosis. Are the methods proven and are they reliable? Recommendations for clinical trials in knee osteoarthritis, state it is essential that reproducible radiographs are obtained for reliable assessment of progression. Two radiographic views of the knee have been proposed; which provides the more reliable assessment, the knee in extension or semi-flexed? Compared with standard radiography, does microfocal radiography make a difference to patient numbers required for drug trials?