Working Diagnosis:
Non-displaced subchondral fracture of the posterior lateral non-weight bearing portion of the left femoral condyle with associated grade 2 MCL sprain and medial meniscal tear

Treatment:
The patient was initially recommended to get a hinged brace for stabilization and encouraged to maintain range of motion. After an informal consult and MRI review with orthopedic surgery, it was agreed that surgical intervention was not recommended, and the patient was advised to maintain weight-bearing as tolerated. She was sent to physical therapy for rehabilitation and eventually sports specific training.

Osteopathic Considerations:
Counterstrain and facilitated positional release for the knee joint was considered to alleviate tenderness along medial joint line and MCL. Myofascial/popliteal spread can be done as well to increase lymphatic drainage proximal to the joint.

Outcome:
During her four-week re-evaluation, she was doing well. There were no changes on repeat x-rays. At six weeks, she stopped therapy due to pain. At her 10-week re-evaluation, she was encouraged to continue therapy after developing knee stiffness and continued tenderness at the lateral femoral condyle. At 14 weeks post injury, the patient had made significant progress during physical therapy and was doing very well without medial meniscal symptoms. A MRI was repeated and it documented complete healing of both the fracture and MCL. Case Photo #4 The patient was released to her normal activity without any restrictions.

Author's Comments:
Subchondral fractures underlay the cortex and the subchondral bone plate, without cortical contour abnormality or disruption. They may be due to chronic low intensity stress. Osteochondral fractures involve cartilage and the subchondral bone plate and may demonstrate cortical disruption, cortical depression, and/or fragmentation. Both fractures may occur in the setting of acute trauma, often in a young athletic patient, with recognizable injury patterns, such as injury to the terminal sulcus of the lateral femoral condyle associated with ACL tears. Although subchondral fractures of the lateral femoral condyle are reported, there are few documented mechanisms of the injury.

Osteochondral fractures of the lateral femoral condyle as a result of a sudden twist or valgus strain are rarely reported in literature. We are not aware of any reports that illustrate subchondral fractures after a valgus stress injury mechanism. This report highlights a rare underdiagnosed fracture given the unique injury mechanism.

Editor's Comments:
Subchondral fractures typically present at articular regions of weight bearing joints (knee, hip, ankle). These can occur secondary to a singular high force injury, as in this case, or due to repetitive loading forces resulting in a subchondral insufficiency fracture. Subchondral fractures are more likely in those with lower bone mineral density. If left untreated, these injuries could progress to subchondral collapse, osteochondral fractures, or osteochondral defects.

References:
Burdett P. Subchondral Fractures. Radsource. https://radsource.us/subchondral-fractures/. Published 2019.

Depasquale R, Fotiadou A, Kumar DS, Lalam R, Tins B, Tyrrell PN, Singh J, Cassar-Pullicino VN. Subchondral impaction fractures of the non-weight-bearing portion of the lateral femoral condyle. Skeletal Radiol. 2013 Feb;42(2):177-85.

Datta, O.R., Burina, O.L., Romanelli, O.F., & Flaum, D.F. Knee Pain in Adults with an Osteopathic Component. Osteopathic Family Physician. 2017 Feb; 9 (1): 26-35.

Matthewson MH, Dandy DJ. Osteochondral fractures of the lateral femoral condyle: a result of indirect violence to the knee. J Bone Joint Surg Br. 1978 May;60-B(2):199-202.

Return To The Case Studies List.