Economic Considerations for the Diagnosis and Therapy of Meniscal Lesions: Can Magnetic Resonance Imaging Help Reduce the Expense?

Abstract

With magnetic resonance imaging (MRI) the surgeon has such an effective diagnostic tool in the diagnosis of a meniscal lesion that the times of diagnostic arthroscopy should be in the past. A total of 823 patients with clinically diagnosed meniscal lesions were divided into two groups: group A, 143 patients underwent MRI and 75 of those arthroscopy; group B, 680 patients, 201 (30%) of whom were operated after being only clinically examined. MRI was done on a Siemens Medical System Magnetom 1.5 Tesla with a 256 x 256 matrix. Spinal echo and gradient echo images were performed with slices of 2 to 4 mm thickness. All meniscal tears were graded according to Reicher and Crues, respectively. Grades III and IV were judged to be positive for a meniscal lesion. Arthroscopy was carried out under general anesthesia and the usual technique. The MRI revealed the following results: Medial meniscus: accuracy 95%, positive predictive value (PPV) 92%, negative predictive value (NPV) 95%, sensitivity 98%, and specificity 82%, lateral meniscus: accuracy 97%, PPV 92%, NPV 98%, sensitivity 94%, and specificity 98%. The overall values for MRI of the medial and lateral menisci combined were: accuracy 96%, PPV 93%, NPV 98%, sensitivity 96%, and specificity 90%. The clinical examination often failed to diagnose a meniscal lesion: accuracy 64%, PPV 59%, NPV 89%, sensitivity 96%, and specificity 33% for the medial meniscus. For the lateral meniscus the accuracy was 91%, PPV 61%, NPV 98%, sensitivity 89%, and specificity 91%. The overall values for the clinical investigation of the medial and lateral menisci combined were: accuracy 78%, PPV 60%, NPV 94%, sensitivity 93%, and specificity 62%. Investigation of all 201 patients operated from group B with MRI would have cost $160,800. The cost of 30% fewer arthroscopies would have been $562,800--in total $723,600. The operation of all 201 patients cost $804,000. Hence about $80,000 could have been saved by scanning all 201 patients and therefore reduce the rate of diagnostic arthroscopies.

Accuracy of Magnetic Resonance in Identifying Traumatic Intraarticular Knee Lesions

“…Weinstabl et al, 48 studying the cost-benefit of knee magnetic resonance, evaluated 201patients with clinical signs of knee meniscal lesions who later had undergone arthroscopy. They report that 30% of the diagnoses were false-positives, and that 30% fewer arthroscopies would have resulted in an economy of US $723,600 dollars.…”

Costs and effectiveness of a brief MRI examination of patients with acute knee injury

“…The main purpose of MRI for knee trauma is to determine if therapeutic arthroscopy is indicated, usually in the case of persisting symptoms. This application of MRI has been studied extensively [1][2][3][4][5]. MRI is, however, rarely performed at initial presentation of a patient with an acute knee trauma, mainly because of the generally high costs, long examination duration, and limited availability in this clinical setting.…”

Protocolo de Investigación: Validación de Resonancia Magnética en Meniscopatías Comparado con Artroscopía. Pacientes de Traumatología del Hospital de Especialidades José Carrasco Arteaga. Cuenca - Ecuador. 2016-2017

“…En otro estudio se uso la RM con sensibilidad: 96 %, especificidad: 90 %, exactitud diagnóstica: 96 %, VPP 93 %, VPN 98 % para la detección de lesión en ambos meniscos [27].…”