MRI preferable to diagnostic arthroscopy in knee joint injuries. A double-blind comparison of 47 patients

Treatment of Combined Injuries to the ACL and the MCL Complex: A Consensus Statement of the Ligament Injury Committee of the German Knee Society (DKG)

Background:

Different indications and treatment options for combined injuries to the anterior cruciate ligament (ACL) and medial collateral ligament complex (MCL) are not clearly defined.

Purpose:

To perform a modified Delphi process with the Committee for Ligament Injuries of the German Knee Society (DKG) in order to structure and optimize the process of treating a combined injury to the ACL and MCL.

Study Design:

Consensus statement.

Methods:

Scientific questions and answers were created based on a comprehensive literature review using the central registers for controlled studies of Medline, Scopus, and Cochrane including the terms medial collateral ligament, anterior cruciate ligament, MCL, ACL, and outcome used in various combinations. The obtained statements passed 3 cycles of a modified Delphi process during which each was readjusted and rated according to the available evidence (grades A-E) by the members of the DKG Ligament Injuries Committee and its registered guests.

Results:

The majority of answers, including several questions with >1 graded answer, were evaluated as grade E (n = 16) or C (n = 10), indicating that a low level of scientific evidence was available for most of the answers. Only 5 answers were graded better than C: 3 answers with a grade of A and 2 answers with a grade of B. Only 1 answer was evaluated as grade D. An agreement of >80% (range, 83%-100%) among committee members was achieved for all statements.

Conclusion:

The results of this modified Delphi process offer a guideline for standardized patient care in cases of combined injuries to the ACL and MCL.

Accuracy of MRI Diagnosis of Meniscal Tears of the Knee: A Meta-Analysis and Systematic Review

This study aimed to evaluate the overall diagnostic value of magnetic resonance imaging (MRI) in patients with suspected meniscal tears. PubMed, Cochrane, Embase database updated to November 2017 were searched by the index words to identify qualified studies, including prospective cohort studies and cross-sectional studies. Literature was also identified by tracking using reference lists. Heterogeneity of the included studies was reviewed to select proper effects model for pooled weighted sensitivity, specificity, and diagnostic odds ratio (DOR). Summary receiver operating characteristic (SROC) analyses were performed for meniscal tears. A total of 17 studies were involved in this meta-analysis to explore the diagnostic accuracy of MRI for meniscal tears. The global sensitivity and specificity of MRI of meniscal tears were 92.0% (95% confidence interval [CI]: 88.0-95.0%) and 90.0% (95% CI: 85.0-95.0%) in medial meniscal tears, and 80.0% (95% CI: 66.0-89.0%) and 95.0% (95% CI: 91.0-97.0%) in lateral meniscal tears, respectively. Moreover, the global positive and negative likelihood ratio of MRI of meniscal tears were 10.33 (95% CI: 6.04-17.67) and 0.09 (95% CI: 0.05-0.14) in medial meniscal tears; 16.48 (95% CI: 8.81-30.83) and 0.21 (95% CI: 0.12-0.37) in lateral meniscal tears, respectively. The global DOR was 81.69 (95% CI: 37.94-175.91) in medial meniscal tears and 56.59 (95% CI: 22.51-142.28) in lateral meniscal tears. The results of area under the SROC indicated high accuracy in medial meniscal tears (area under the curve [AUC] = 0.97, 95% CI: 0.95-0.98) and lateral meniscal tears (AUC = 0.96, 95% CI: 0.94-0.97). This review presents a systematic review and meta-analysis to evaluate the diagnostic accuracy of MRI of meniscal tears. Moderate-to-strong evidence suggests that MRI appears to be associated with higher diagnostic accuracy for detecting medial and lateral meniscal tears.

The accuracy of magnetic resonance imaging diagnosis of non-osseous knee injury at Steve Biko Academic Hospital

Background

Preoperative magnetic resonance imaging (MRI) has internationally been proven to reduce unnecessary knee arthroscopies and assist with surgical planning. This has the advantage of avoiding unnecessary surgery and the associated anaesthetic risk, as well as reducing costs. No data were found in the recently published literature assessing the accuracy of MRI interpretation of knee ligament injury in the public sector locally.

Objectives

This pilot study aimed to determine the accuracy of MRI in detecting non-osseous knee injury in a resource-limited tertiary-level academic hospital in Pretoria, South Africa, compared to the gold standard arthroscopy findings.

Method

This was an exploratory retrospective analysis of 39 patients who had MRI and arthroscopy at Steve Biko Academic Hospital (SBAH). True positive, true negative, false positive and false negative results were extrapolated from findings in both modalities and translated into sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each structure.

Results

Negative predictive values were recorded as 97%, 81%, 90% and 100% (anterior cruciate ligament [ACL], medial meniscus [MM], lateral meniscus [LM] and posterior cruciate ligament [PCL], respectively), which were comparative to recently published international literature. The PPV results were lower than those previously evaluated at 55%, 58%, 55% and not applicable. The sensitivities and specificities of the ligaments were 83%, 58%, 83% and not applicable; and 87%, 81%, 70% and not applicable, respectively.

Conclusion

Magnetic resonance imaging was found to be sensitive and specific, with a high NPV noted in all structures evaluated. Negative results can therefore be used to avoid unnecessary surgery to the benefit of the patient and state. The study reiterates that high accuracy can be obtained from MRI on a 1.5-tesla non-dedicated scanner, with interpretation by generalist radiologists.

Confirming the Presence of Unrecognized Meniscal Injuries on Magnetic Resonance Imaging in Pediatric and Adolescent Patients With Anterior Cruciate Ligament Tears

BACKGROUND

Prior research has shown decreased accuracy of meniscal injury detection using magnetic resonance imaging (MRI) for anterior cruciate ligament (ACL)-deficient adult patients as well as ACL-deficient pediatric and adolescent patients. The objectives of this study were the following: (1) assess the diagnostic ability of MRI in detecting meniscal injuries for pediatric and adolescent patients undergoing arthroscopic ACL reconstruction and (2) characterize the unrecognized meniscal injuries.

METHODS

The sensitivity, specificity, positive predictive value, and negative predictive value of meniscal tears (medial, lateral, or both) on MRI were calculated for the 107 patients in this cohort. Fisher exact tests were used to compare event frequencies between medial meniscal (MM) and lateral meniscal (LM) tears. One-way analysis of variance tests were performed to compare event rates between the location and type of unrecognized meniscal tears.

RESULTS

The median age of the cohort was 15 (range: 7 to 18). The sensitivity, specificity, positive predictive value, and negative predictive value of MRI in detecting meniscal tears (medial, lateral, or both) in ACL-deficient pediatric and adolescent patients was 62.3%, 68.4%, 78.2%, and 50.0%, respectively. There were 26 (24.3%) cases in which a meniscal injury was not detected on MRI, but was discovered arthroscopically (MM: 5 knees, LM: 20 knees, both: 1 knee). These unrecognized meniscal injuries were more commonly the LM than the MM (77.8%, P-value=0.100), a vertical/longitudinal tear type (77.8%, P-value <0.001), and located in the posterior horn (74.1%, P-value <0.001).

CONCLUSIONS

In this ACL-deficient pediatric and adolescent cohort, there were 26 (24.3%) patients with unrecognized meniscal injuries. A vertical tear in the posterior horn was the most commonly unrecognized meniscal injury, supporting the findings of prior research postulating that the location and configuration of a tear influence the accuracy of MRI in detecting these injuries. More research is needed to investigate strategies to improve the detection of meniscal tears in pediatric and adolescent patients preoperatively. These findings have implications with regard to patient counseling, operative planning, anticipatory guidance with regard to postoperative rehabilitation, recovery expectations, and surgical outcomes.

LEVEL OF EVIDENCE

Level IV.

Use of MRI by radiologists and orthopaedic surgeons to detect intra-articular injuries of the knee

OBJECTIVE

Magnetic resonance imaging (MRI) is paramount in the assessment of knee pathology, particularly when planning for a surgical procedure. This study compared the diagnostic accuracy in MRI reading of pathological knees by radiologists and orthopaedic surgeons.

MATERIALS AND METHODS

Cross-sectional study comprising 80 randomly selected patients previously submitted to arthroscopic surgery after clinical examination and MRI. A diagnosis by MRI interpretation was requested from the two teams, one of radiologists and another of orthopaedic surgeons. The conclusions of each team were later compared. Statistical significance was considered for p < 0.05.

RESULTS

The radiologists' findings achieved statistical significance regarding osteochondral injuries, ACL, and medial meniscus (p < 0.05), and orthopaedic surgeons regarding ACL injuries and menisci (p < 0.05). ACL injuries demonstrated a statistically significant association between teams (p < 0.001).

CONCLUSIONS

MRI appears to offer reliable readings of ACL injuries, regardless the specialty of the observer. The lateral compartment is scarcely well read.

A systematic review and meta-analysis of the diagnostic accuracy of MRI for suspected ACL and meniscal tears of the knee

PURPOSE

To determine the diagnostic accuracy of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of anterior cruciate ligament (ACL), medial meniscus and lateral meniscus tears in people with suspected ACL and/or meniscal tears.

METHODS

MEDLINE, Web of Science and the Cochrane library were searched from inception to March 2014. All prospective studies of the diagnostic accuracy of MRI or US against arthroscopy as the reference standard were included in the systematic review. Studies with a retrospective design and those with evidence of verification bias were excluded. Methodological quality of included studies was assessed using the QUADAS-2 tool. A meta-analysis of studies evaluating MRI to calculate the pooled sensitivity and specificity for each target condition was performed using a bivariate model with random effects. Sub-group and sensitivity analysis were used to examine the effect of methodological and other study variables.

RESULTS

There were 14 studies included in the meta-analysis of the accuracy of MRI for ACL tears, 19 studies included for medial meniscal tears and 19 studies for lateral meniscal tears. The summary estimates of sensitivity and specificity of MRI were 87 % (95 % CI 77-94 %) and 93 % (95 % CI 91-96 %), respectively, for ACL tears; 89 % (95 % CI 83-94 %) and 88 % (95 % CI 82-93 %), respectively, for medial meniscal tears; and 78 % (95 % CI 66-87 %) and 95 % (95 % CI 91-97 %), respectively, for lateral meniscal tears. Magnetic field strength had no significant effect on accuracy. Most studies had a high or unclear risk of bias. There were an insufficient number of studies that evaluated US to perform a meta-analysis.

CONCLUSION

This study provides a systematic review and meta-analysis of diagnostic accuracy studies of MRI and applies strict exclusion criteria in relation to the risk of verification bias. The risk of bias in most studies is high or unclear in relation to the reference standard. Concerns regarding the applicability of patient selection are also present in most studies.

LEVEL OF EVIDENCE

III.

Diagnosis of knee injuries: comparison of the physical examination and magnetic resonance imaging with the findings from arthroscopy

Objectives

To ascertain the sensitivity, specificity, accuracy and concordance of the physical examination (PE) and magnetic resonance imaging (MRI) in comparison with arthroscopy, in diagnosing knee injuries.

Methods

Prospective study on 72 patients, with evaluation and comparison of PE, MRI and arthroscopic findings, to determine the concordance, accuracy, sensitivity and specificity.

Results

PE showed sensitivity of 75.00%, specificity of 62.50% and accuracy of 69.44% for medial meniscal (MM) lesions, while it showed sensitivity of 47.82%, specificity of 93.87% and accuracy of 79.16% for lateral meniscal (LM) lesions. For anterior cruciate ligament (ACL) injuries, PE showed sensitivity of 88.67%, specificity of 94.73% and accuracy of 90.27%. For MM lesions, MRI showed sensitivity of 92.50%, specificity of 62.50% and accuracy of 69.44%, while for LM injuries, it showed sensitivity of 65.00%, specificity of 88.46% and accuracy of 81.94%. For ACL injuries, MRI showed sensitivity of 86.79%, specificity of 73.68% and accuracy of 83.33%. For ACL injuries, the best concordance was with PE, while for MM and LM lesions, it was with MRI (p < 0.001).

Conclusions

Meniscal and ligament injuries can be diagnosed through careful physical examination, while requests for MRI are reserved for complex or doubtful cases. PE and MRI used together have high sensitivity for ACL and MM lesions, while for LM lesions the specificity is higher.

Level of evidence II – Development of diagnostic criteria on consecutive patients (with universally applied reference “gold” standard).

Efficacy of magnetic resonance imaging evaluation for meniscal tear in acute anterior cruciate ligament injuries

PURPOSE

The objective of this study was to compare the preoperative magnetic resonance imaging (MRI) diagnostic rates of meniscal injuries combined with acute anterior cruciate ligament (ACL) injuries, as well as traumatic meniscal injuries without ACL injuries.

METHODS

From January 2005 through April 2013, 208 patients who underwent ACL reconstruction and 1,334 patients with traumatic meniscal tear injuries were examined by MRI and arthroscopy. Patients with chronic ACL injuries, revisions, fracture histories, or multiple-ligament injuries and patients with Outerbridge degenerative changes of grade 3 or greater were excluded, yielding 159 patients and 621 patients in the 2 groups, respectively. The medial meniscus (MM) and lateral meniscus (LM) examined by MRI and arthroscopy for findings of tears were compared in each group. The sensitivity, specificity, positive predictive value, and negative predictive value for MM and LM tears by MRI were compared and analyzed statistically.

RESULTS

The diagnostic sensitivity of MRI in the group with ACL injury was significantly lower than that in the ACL-intact group for the MM (P < .001) and LM (P = .040). The negative predictive value was also lower in the group with ACL injury for both the MM (P = .008) and LM (P < .001). There was no statistical difference in specificity and positive predictive value between the 2 groups.

CONCLUSIONS

This study showed that if a patient had an acute ACL tear, the sensitivity and negative predictive value of MRI for a meniscal tear were less than if there was no ACL tear, which led to the low diagnostic accuracy of MRI.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Unicompartmental knee prosthetization: Which key-points to consider?

Unicompartmental knee arthroplasty (UKA) has evolved into a suitable option for diseased knees that cannot be managed with arthroscopic treatment and at the same time are not good candidates for total knee replacement. Since meticulous execution of the surgical technique is essential to optimizing UKA outcome, some procedural key-points are mandatory. Templates (phantoms) are then used to size the required prosthetic component (using these radiographs. Arthritic varus (or valgus) knees with an asymptomatic patello-femoral joint are typically ideal for UKA. Metal-backed tibial components should be favourite instead of all-polyethylene tibial components to avoid polyethylene creep that may occur in fixed bearings. Moreover, a proper thickness of the polyethylene layer is mandatory, in order to avoid early failure.

Magnetic resonance imaging in the evaluation of meniscal tear

Background: Magnetic resonance imaging (MRI) has been recognized as the imaging method for non-invasive evaluation of knee pathology, particular meniscus and ligaments. Objective: Compare the sensitivity, specificity, and accuracy of MRI in the detection of meniscal tears with arthroscopy. Material and methods: Twenty-seven patients who were diagnosed as meniscal tear on arthroscopy with preoperative MRI were included in this study between January 2003 and June 2008. MRI was performed with a 1.5 Tesla Signa Horizon Echospeed MRI for eight patients between January 2003 and June 2005 and a 1.5 Tesla Signa Excited HD MRI for nineteen patients between July 2005 and June 2008. The location of meniscal tear was evaluated by studying three areas: anterior horn, body and posterior horn. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the anterior horn, body, posterior horn and overall meniscus were calculated. Results: The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn, and overall medial meniscus was 42.9%, 87.5%, 94.1%, and 81.3%, respectively. The specificity was 95.0%, 84.2%, 81.8%, and 88.0%, respectively. The accuracy was 81.5%, 85.2%, 89.3%, and 85.4%, respectively. The PPV was 75.0%, 70.0%, 88.9%, and 81.2%, respectively. The NPV was 82.6%, 94.1%, 90.0%, and 88.0%, respectively. The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn and overall lateral meniscus was 0%, 100%, 85.7%, and 80.0%, respectively. The specificity was 100%, 100%, 90.5% and 97.2%, respectively. The accuracy was 96.0%, 100%, 90.5%, and 97.2%, respectively. The PPV was 100%, 75% and 80%, respectively. The NPV was 96.3%, 100%, 95.0%, and 97.2%, respectively. Conclusion: MRI is a helpful technique to detect meniscal tear with different sensitivity and accuracy on the meniscal location.

Role of Sonographic Examination in Traumatic Knee Internal Derangement

OBJECTIVES

To define the accuracy (compared with magnetic resonance imaging [MRI]) of sonographic examination in detecting knee effusion and to determine whether the presence of knee effusions in patients with traumatic knee injury can predict knee internal derangement as assessed by MRI.

DESIGN

Prospective study.

SETTING

Hospital rehabilitation department.

PARTICIPANTS

Thirty patients (19 men, 11 women) with traumatic knee injury were recruited. Subjects received sonographic examination and MRI on the same day.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The presence or absence of knee effusion was assessed by sonographic examination. MRI was used as criterion standard to evaluate whether the presence of knee effusion and internal derangement, which included tear of anterior and posterior cruciate ligaments, as well as meniscus tear.

RESULTS

The sensitivity of sonographic examination for detecting knee effusion was 79.1%, and specificity was 50%. The positive-predictive value (PPV) was 86.3% and negative-predictive value (NPV) was 37.5%. The PPV of sonographic effusion to internal derangement was 90.9%, and the NPV was 37.5%.

CONCLUSIONS

Sonographic examination can accurately detect effusion of the knee. The detection of knee effusion in patients with traumatic knee injury by sonographic examination is highly indicative of internal knee derangement.

The diagnosis of meniscus tears: the role of MRI and clinical examination

Magnetic resonance imaging (MRI) and clinical examination are tools commonly used in the diagnosis of meniscus tears. It has been suggested routine MRI before therapeutic arthroscopy for clinically diagnosed meniscus tears will reduce the number and cost of unnecessary invasive procedures. We designed a systematic review of prospective cohort studies comparing MRI and clinical examination to arthroscopy to diagnosis meniscus tears. Thirty-two relevant studies were identified by a literature review. Careful evaluation by an experienced examiner identifies patients with surgically treatable meniscus lesions with equal or better reliability than MRI. MRI is superior when indications for arthroscopy are solely diagnostic. However, the methods by which such a clinician arrives at a conclusion have not been identified. To create an evidence-based algorithm for the diagnosis of a meniscus tear future investigations should prospectively assess the value of commonly used aspects of the patient history and meniscus tests. MRI is useful, but should be reserved for situations in which an experienced clinician requires further information before arriving at a diagnosis. Indications for arthroscopy should be therapeutic, not diagnostic in nature.

MR Imaging: Effectiveness and Costs at Triage of Patients with Nonacute Knee Symptoms

PURPOSE

To prospectively evaluate the cost and effectiveness of magnetic resonance (MR) imaging performed to exclude the need for arthroscopy in patients with nonacute knee symptoms who are highly suspected clinically of having intraarticular knee abnormality.

MATERIALS AND METHODS

The study was approved by the institutional review boards of three hospitals; informed patient consent was obtained. All 584 included patients (406 male, 178 female; mean age, 31.1 years+/-8.0 [standard deviation]) underwent MR imaging. Patients with an MR result positive for the diagnosis of intraarticular knee abnormality underwent arthroscopy (group A). Patients with a negative MR result were randomly assigned to undergo either conservative (group B) or arthroscopic (group C) treatment. Treatment was considered effective if the Noyes function score had increased 10% or more at 6 months. A cost analysis was performed from a societal perspective to compare the treatment strategy involving MR imaging with the strategy not involving MR imaging.

RESULTS

Of the 584 patients, 294 (50.3%) were assigned to group A; 149 (25.5%), to group B; and 141 (24.1%), to group C. At 6 months, the number of patients effectively treated in group B (conservative treatment) was a mean of 5.1%+/-10.0 larger than the number of patients effectively treated in group C (arthroscopy). Owing to savings in productivity costs, total societal costs were lower with use of the strategy involving MR imaging by a mean of $153+/-488 (P=.54).

CONCLUSION

MR imaging can be used without additional costs or disadvantageous effects on function to obviate arthroscopy in patients with nonacute knee symptoms who are highly suspected of having intraarticular knee abnormality.

MRI-negative bucket-handle tears of the lateral meniscus in athletes: a case series

Magnetic resonance imaging (MRI) is the most widely used non-invasive test for assessing intra-articular injuries of the knee. It has been suggested that a negative MRI can be useful in avoiding the need for diagnostic arthroscopy in cases where clinical examination is equivocal. However, the sensitivity and specificity of MRI is not 100%, particularly for tears of the lateral meniscus. Furthermore, a false negative MRI scan may result in premature return to play in athletes, resulting in increased risk of further damage to a torn meniscus. To illustrate this issue, we present a case series of eight elite athletes who all presented with mechanical knee symptoms and where MRI scans revealed no significant intra-articular pathology. Five of the athletes were allowed to return to sport on the basis of a negative MRI. All patients were subsequently found to have a bucket-handle tear of their lateral meniscus at arthroscopy. Two independent, experienced musculoskeletal radiologists were asked to review the MRI films without being given any clinical history of the cases. Although injuries to the popliteus tendon were noted in two of the athletes who had sustained a recent acute injury to their knee, no meniscal tears were identified. Thus arthroscopy remains the gold standard for the assessment and management of high-demand patients with a clinical suspicion of meniscal pathology.

Imaging evaluation of meniscal injury of the knee joint: a comparative MR imaging and arthroscopic study

To evaluate the efficacy of MR imaging in the diagnosis and classification of meniscal tear of the knee joint, we retrospectively characterized the MR features of 78 meniscal tears in 148 patients according to the Mesgarzadeh's criteria. The results showed that the sensitivity and specificity for meniscal tears were 92% and 87%, respectively. Type VI meniscal tear was the most common type, especially in displaced meniscal tear. MR is a reliable diagnostic tool for meniscal tears and associated cruciate ligament injury.

Magnetic resonance imaging of anterior cruciate ligament rupture

Background

Magnetic resonance (MR) imaging is a useful diagnostic tool for the assessment of knee joint injury. Anterior cruciate ligament repair is a commonly performed orthopaedic procedure. This paper examines the concordance between MR imaging and arthroscopic findings.

Methods

Between February, 1996 and February, 1998, 48 patients who underwent magnetic resonance (MR) imaging of the knee were reported to have complete tears of the anterior cruciate ligament (ACL). Of the 48 patients, 36 were male, and 12 female. The average age was 27 years (range: 15 to 45). Operative reconstruction using a patellar bone-tendon-bone autograft was arranged for each patient, and an arthroscopic examination was performed to confirm the diagnosis immediately prior to reconstructive surgery.

Results

In 16 of the 48 patients, reconstructive surgery was cancelled when incomplete lesions were noted during arthroscopy, making reconstructive surgery unnecessary. The remaining 32 patients were found to have complete tears of the ACL, and therefore underwent reconstructive surgery. Using arthroscopy as an independent, reliable reference standard for ACL tear diagnosis, the reliability of MR imaging was evaluated. The true positive rate for complete ACL tear diagnosis with MR imaging was 67%, making the possibility of a false-positive report of "complete ACL tear" inevitable with MR imaging.

Conclusions

Since conservative treatment is sufficient for incomplete ACL tears, the decision to undertake ACL reconstruction should not be based on MR findings alone.

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.

Acute traumatic hemarthrosis of the knee. Is routine arthroscopic examination necessary? A study of 320 consecutive patients

BACKGROUND AND AIMS

Distortions and contusions of the knee are common. Fairly often they will result in hemarthrosis. The purpose of this study was to evaluate the findings in patients with acute traumatic hemarthrosis of the knee and based on these findings estimate the necessity of acute arthroscopic examination.

MATERIAL AND METHODS

A total of 320 patients were examined arthroscopically between the years 1994 to 96 in the Turku University Hospital. Patients with other than chondral or osteochondral fractures were excluded.

RESULTS

The most common arthroscopic findings were rupture of the ACL (45%), dislocation of the patella (23%) and meniscal tear (21%). In only 113 (35%) cases an immediate therapeutic procedure was performed in addition to the arthroscopic examination.

CONCLUSIONS

Based on our findings we believe that routine arthroscopic examination is not necessary in patients with acute traumatic hemarthrosis of the knee. In our opinion the patient should be examined and followed by an orthopedic surgeon and if a lesion requiring operative treatment is diagnosed or suspected, an arthroscopic examination should be scheduled. The timing of the procedure should be such that all possible lesions encountered can be treated in the same operation.

MR imaging of the menisci and cruciate ligaments: a systematic review

PURPOSE

To systematically review and synthesize published data on the diagnostic performance of magnetic resonance (MR) imaging of the menisci and cruciate ligaments and to assess the effect of study design characteristics and magnetic field strength on diagnostic performance.

MATERIALS AND METHODS

Articles published between 1991 and 2000 were included if at least 30 patients were studied, arthroscopy was the reference standard, the magnetic field strength was reported, positivity criteria were defined, and the absolute numbers of true-positive, false-negative, true-negative, and false-positive results were available or derivable. Pooled weighted and summary receiver operating characteristic (ROC) analyses were performed for tears of both menisci and both cruciate ligaments separately and for the four lesions combined, by using random effects models. Differences were assessed according to lesion type.

RESULTS

Twenty-nine of 120 retrieved articles were included. Pooled weighted sensitivity was higher for medial meniscal tears than that for lateral meniscal tears. However, pooled weighted specificity for the medial meniscus was lower than that for the lateral meniscus. In summary ROC analyses performed per lesion, various study design characteristics were found to influence diagnostic performance. Higher magnetic field strength significantly improved discriminatory power only for anterior cruciate ligament tears. When all lesions were combined in one overall summary ROC analysis, magnetic field strength was a significant but modest predictor of diagnostic performance.

CONCLUSION

Diagnostic performance of MR imaging of the knee is different according to lesion type and is influenced by various study design characteristics. Higher magnetic field strength modestly improves diagnostic performance, but a significant effect was demonstrated only for anterior cruciate ligament tears.

Effectiveness of MR imaging in selection of patients for arthroscopy of the knee

PURPOSE

To determine the effectiveness of magnetic resonance (MR) imaging in the appropriate identification of those patients with a high clinical suspicion of internal derangements of the knee who require arthroscopic therapy.

MATERIALS AND METHODS

In a prospective multicenter study, MR imaging was performed at 0.5 T in 430 consecutive patients. The sensitivity and specificity of MR imaging in the patients who underwent arthroscopy and the corrected sensitivity and specificity of MR in all the study patients were calculated. For this correction, patients with negative MR and arthroscopic results were considered representative of the patients with negative MR results who were conservatively treated, and the number of the former was doubled. The standard errors of the corrected values were adjusted with the delta method.

RESULTS

At MR imaging, arthroscopy was indicated in 221 patients, 200 of whom underwent arthroscopy. Two hundred nine patients with negative MR imaging results were randomized for arthroscopic (105 patients) or for conservative treatment (104 patients). Of the 105 patients randomized for arthroscopy, 93 actually underwent arthroscopy. Arthroscopic treatment was necessary in 13 of 93 patients with a negative diagnosis at MR imaging. Arthroscopic treatment was necessary in 179 of 200 patients with a positive diagnosis at MR (sensitivity, 93.2%; specificity, 79.2%). Sensitivity and specificity corrected for randomization were 87.3% and 88.4%. Sensitivity and specificity corrected for randomization, respectively, were 84.1% and 94.2% for the diagnosis of medial meniscal tears and 69.5% and 94.5% for the diagnosis of lateral meniscal tears at MR.

CONCLUSION

MR imaging is an effective tool in the selection of patients for arthroscopy from among a general population.

Observation of anomalous insertion of the medial meniscus on the anterior cruciate ligament

We wanted to determine the frequency of occurrence and types of anomalous insertions of the medial meniscus to the anterior cruciate ligament (ACL) in Finnish patients. In 987 consecutive arthroscopies from January 1996 to August 1998, the meniscal pathology was mapped using videoprints and drawings. We found 11 anomalous medial meniscus insertions to the ACL. There were 4 female and 6 male patients in the series. In 1 woman, the anomaly was bilateral. The mean age of the patients was 30.6 years (range 14 to 63 years). The anomalous band was excised in all patients. The anomaly usually was not the finding that caused the need for arthroscopy. In 3 knees, the anomaly was the only pathologic finding. The frequency of this anomaly occurring was approximately 1.2%. The anomalous medial meniscus insertion to the ACL is a very rare clinical finding. Arthroscopic surgeons should be aware of its existence as well as of other anterior horn insertion variations of the medial meniscus.

A new computer-based triage tool for patients with knee disorders

The Birmingham Knee Interview (BKI) is a computer-based questionnaire that has been developed to triage patients with knee disorders in the 16-50 years age group. The BKI was developed as a triage tool by analysing the interview responses of 150 patients against their final diagnosis. The latter was determined by the findings at arthroscopy, clinical examination or special investigations (e.g. MRI). Based on the final diagnosis patients were divided into two groups. Group I contained those patients with pathologies that need assessment by a surgeon, while group II are those who do not. Twenty-five different questions showed statistical significance (P<0.05) in identifying a patient falling into one group or another. The weight of evidence of each chosen answer from these questions was calculated. The computer was then programmed to automatically sum these weights with a decision based on the score. A trial on a further 82 patients showed a correct decision of the computer software in 71 patients. In conclusion, the BKI provides an automated method for triaging patients with knee disorders that is 86.7% (S.E. 3.7%) accurate.

Technical pitfalls of meniscal surgery

Meniscal surgery is one of the most common orthopedic procedures performed today. Orthopedic surgeons must be familiar with the indications for meniscal excision versus repair and comfortable with the diverse instrumentation used for both techniques. Numerous pitfalls exist in diagnosis, indication, and technical aspects of surgery but can be minimized or avoided by careful preoperative planning and attention to detail during the surgical procedure.