Working Diagnosis:
Osteochondral Defect.

Treatment:
After initial evaluation, the patient was started on a rehabilitation routine with her Athletic Trainers (ATCs) for a presumed recurrent ACL tear. She had significant improvement in her pain and mobility in the 3 weeks prior to advanced imaging being obtained. She was re-evaluated the day following her MRI and was pain free with an essentially normal physical exam. After re-evaluation, rehabilitation was advanced.

Outcome:
At the time of this submission, the patient had begun light jogging/running without pain. She will continue to progress her activity back to full.

Author's Comments:
Lateral femoral notch sign (LFNS) is defined as a deep depression on the lateral femoral condyle near the tibial and patellar articular surfaces (the terminal sulcus). Patients with normal ACLs typically do not have a sulcus deeper than 1.2 mm. A sulcus deeper than 1.5 mm is indicative of an ACL tear. It is unclear if the LFNS noted on x-ray Case Photo #1 Case Photo #2 was from her original ACL injury or her new injury. MRI did show an osteochondral lesion Case Photo #5 . With the bone edema on MRI Case Photo #6 , it is unclear if this was a new injury or an exacerbation of a preexisting lesion. Osteochondral lesions can result from acute injury and can also be idiopathic, known as osteochondritis dissecans. Osteochondral lesions are more common in males but rates are increasing in women, most likely due to increased sports participation.

Editor's Comments:
This case underscores the importance of evaluating available prior data, such as imaging and operative reports, related to past injuries when assessing an athlete with a new injury to the same body region.

References:
1. Pao DG. The lateral femoral notch sign. Radiology. 2001 Jun;219(3):800-1. doi: 10.1148/radiology.219.3.r01jn12800. PMID: 11376273.
2. Cobby MJ, Schweitzer ME, Resnick D. The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament. Radiology. 1992 Sep;184(3):855-8. doi: 10.1148/radiology.184.3.1509079. PMID: 1509079.
3. Weiss JM, Shea KG, Jacobs JC Jr, Cannamela PC, Becker I, Portman M, Kessler JI. Incidence of Osteochondritis Dissecans in Adults. Am J Sports Med. 2018 Jun;46(7):1592-1595. doi: 10.1177/0363546518764676. Epub 2018 Apr 3. PMID: 29613834.
4. Williamson LR, Albright JP. Bilateral osteochondritis dissecans of the elbow in a female pitcher. J Fam Pract. 1996 Nov;43(5):489-93. PMID: 8917149.

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