Disclosures: Scott E. Klass, MD, MS, ATC, CSCS: No financial relationships or conflicts of interest

Case Description: Patient presented with 2 months of insidious right medial knee pain, referred for a pes anserine (PA) bursitis injection. The pain was described as sharp and non-radiating. No exacerbating or alleviating factors were identified and he denied swelling. The physical examination yielded tenderness medial to the PA and a severe antalgic gait with negative special testing.

Setting: Tertiary Outpatient Clinic

Patient: 66-year-old obese male Assessment/

Results: Right knee x-rays revealed mild tricompartmental narrowing. Ultrasound yielded an absence of significant effusion surrounding the PA with cortical discontinuity at the medial tibia plateau (MTP), suggesting a possible stress fracture. A follow-up MRI did not reveal fracture line, though showed subchondral signal intensity and reactive edema, highly suggestive of an insufficiency fracture. The patient was made non-weight bearing and referred to endocrinology. He was followed-up in clinic and became weight bearing as tolerated 4 weeks after initial diagnosis.

Discussion: Insufficiency fractures arise when abnormal bone is subjected to normal or excessive loads and presents as acute localized pain. The most common risk factor is osteoporosis, often located in the tibia. Early diagnosis helps prevent remodeling, non-union fractures and loss of function. Unfortunately, x-rays can miss up to 85%, as they are frequently normal until 3 weeks to 3 months when bone callus forms. MRI is both sensitive and specific but can be expensive and inaccessible. Therefore, ultrasonography has utility by providing low cost and high sensitivity imaging to detect stress fractures, especially with superficial bones like the tibia. The hallmark findings on ultrasound include hyperechogenicity of the surrounding soft tissue, thickening of the periosteum, cortical irregularity and increased periosteal color Doppler flow.

Conclusion: This case highlights the importance of a full pre-procedural clinical exam, especially for outside referrals, to avoid unnecessary interventions. In future situations, when clinical suspicion of a fracture exists, ultrasound can be a useful diagnostic aid.

Level of Evidence: Level V

« Back to AAPM&R Annual Assembly 2020

PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/tibial-insufficiency-fracture-diagnosed-with-ultrasound-a-case-report/