Atraumatic Knee Marrow Edema-Like Signal Preceding a Low-Energy Bicondylar Tibial Plateau Fracture in a Patient with Crohn Disease: A Case Report

Summary

A 44-year-old man with Crohn disease developed atraumatic knee marrow edema-like signal and, eight weeks later, a low-energy bicondylar tibial plateau fracture. After fixation and rehabilitation, he was pain-free, walked normally, and had full, painless knee motion at three months.

Abstract

​Bone marrow edema-like signal is a nonspecific magnetic resonance imaging finding whose clinical significance depends on its cause, distribution, associated structural abnormalities, symptoms, and skeletal risk. A 44-year-old construction engineer with Crohn disease and previous systemic corticosteroid exposure developed several weeks of atraumatic, load-related right-knee pain. Available prefracture radiographs showed no visible acute fracture. Noncontrast MRI on 28 July 2025 was reported as showing a medial femoral condyle marrow contusion without a fracture line or subchondral collapse; however, the limited coronal screenshots appeared discordant with the reported localization and were insufficient to establish the precise osseous epicenter without the complete DICOM study. Noncontrast computed tomography on 28 August showed maintained alignment without a visible fracture. Symptoms subsequently worsened during loading. On 22 September, a minor twisting movement while walking was followed by severe pain and inability to bear weight. Radiography and computed tomography demonstrated a comminuted bicondylar tibial plateau fracture, which the source narrative recorded as having been treated with open reduction and internal fixation. At approximately three months postoperatively, he reported no knee pain and had resumed normal walking and usual function; knee range of motion was full and painless. Dual-energy X-ray absorptiometry on 5 February 2026 showed bone mineral density below the expected range for age, with a lowest Z-score of −2.8 at the right total hip. Metabolic laboratory findings were largely within the displayed reference ranges, except for low vitamin B12. The case establishes a temporal sequence but cannot demonstrate direct anatomical progression or causality. Atraumatic marrow edema-like signal accompanied by worsening load-related pain in a patient with systemic skeletal risk factors may warrant diagnostic reassessment, reconsideration of loading, and an individualized bone-health evaluation.

Introduction

Bone marrow edema-like signal is an imaging descriptor rather than a diagnosis. At the knee, it may accompany trauma, stress, or insufficiency injury, osteoarthritis, inflammatory disease, transient bone marrow edema syndrome, osteonecrosis, infection, or neoplasia. The same fluid-sensitive signal pattern can therefore require different management depending on the clinical setting¹. Subchondral insufficiency fracture of the knee is diagnosed by integrating the clinical presentation with MRI findings, particularly a subchondral low-signal fracture line, the distribution of surrounding edema-like signal, and the presence or absence of osteochondr....

Protocol

The following framework is intended for education and clinical reflection. It is not a validated protocol, and each decision should be individualized based on symptoms, imaging, comorbidities, fracture risk, and specialist judgment. This report describes the routine clinical care of a single patient and did not involve a prospective research intervention or experimental human-subject research protocol. Accordingly, formal ethics committee approval was not required for this single-patient case report. Written informed consent was obtained from the patient for publication of this case and the accompanying de-identified imaging. All the materials used in this study are l....

Results

The source narrative recorded open reduction and internal fixation. Available postoperative radiographs (Figure 5A and Figure 5B) confirmed plate-and-screw fixation with maintained reduction, but their metadata did not establish a reliable examination date, and they were not used to claim radiographic union. The source narrative described six weeks of non-weight-bearing, followed by graded rehabilitation; the underlying protocol documentation wa.......

Discussion

This case illustrates why atraumatic marrow edema-like signal should remain a descriptive finding when its cause is uncertain. No trauma preceded symptom onset, yet the MRI report used the etiologic term “contusion.” Conversely, no subchondral fracture line or collapse was reported, so the study cannot be retrospectively reclassified as a proven subchondral insufficiency fracture. When pain worsens during loading and systemic skeletal risk factors are present, the combination may warrant proportionate load mo.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Aquilion Start computed tomography system	Canon Medical Systems; supplied film bears legacy Toshiba Medical Systems branding	Unit-specific catalog number not available https://global.medical.canon/products/computed-tomography/aquilion-start/	Used for the fracture-episode CT after the low-energy bicondylar tibial plateau fracture. The supplied film identifies an Aquilion Start system; other acquisition parameters were not reliably legible.
cobas e 801 immunoassay analyzer	Roche Diagnostics	08454345001 https://diagnostics.roche.com/global/en/products/instruments/cobas-e-801-ins-2202.html	Used for the 25-hydroxyvitamin D electrochemiluminescence immunoassay reported on 8 January 2026. The specific assay reagent/kit catalog number was not available in the supplied record.
Computed tomography system (prefracture right-knee CT)	Not retrievable from retrospective source record	Not retrievable	Noncontrast right-knee CT acquired 28 August 2025. Displayed reconstruction thickness was 2.00 mm. Manufacturer/model were not recoverable. The Aquilion Start fracture-CT system must not be assigned to this earlier examination.
Lunar Prodigy Advance DXA system	GE Healthcare	Unit-specific catalog number not available https://www.gehealthcare.com/en-us/products/bone-and-metabolic-health/prodigy	DXA performed 5 February 2026. Used to report areal BMD, T-scores, and Z-scores at L1-L4 and the bilateral proximal femur/total hip regions. The source record identified the Lunar Prodigy Advance system; a unit-specific catalog number was not available.
Magnetic resonance imaging system (prefracture right-knee MRI)	Not retrievable from retrospective source record	Not retrievable	Outside noncontrast multiplanar, multisequence right-knee MRI acquired 28 July 2025. The full DICOM study was unavailable. The only retrievable PACS series label was Tra_PD_SPIR (24 images), but it could not be assigned to the published coronal panels. Scanner manufacturer/model, field strength, coil, exact sequence, and acquisition parameters were not recoverable.
Orthopedic fixation system (tibial plateau ORIF)	Not retrievable from retrospective source record	Not retrievable	The source narrative recorded open reduction and internal fixation. Postoperative radiographs show two plate constructs with multiple proximal subchondral rafting screws. The operative note and implant identifiers were unavailable; manufacturer/system and precise plate position were not inferred from radiographic appearance.