Working Diagnosis:
Isolated high-grade partial patellar tendon tear at the inferior pole of the patella

Treatment:
The patient was immediately placed in knee immobilizer and instructed to remain non-weight-bearing with crutches for first four days post injury. He then underwent an ultrasound-guided injection of 5 mL of leukocyte-poor platelet-rich plasma into the damaged portion of the patellar tendon. Following the procedure, he completed a four-week rehabilitation program supervised by the athletic training staff. Rehabilitation initially emphasized protected weight-bearing and blood-flow-restriction training before progressing to sport-specific activities.

Outcome:
At four weeks following initiation of rehabilitation, the patient was cleared for full practice participation. At six weeks following injury, he was cleared for game participation. He subsequently participated in remaining eight games of season without limitations.

Author's Comments:
This case demonstrated a unique presentation of an isolated partial patellar tendon tear. The injury mechanism and initial clinical presentation suggested potentially more significant ligamentous or meniscal pathology. Stress placed on the patellar tendon during several knee examination maneuvers may have contributed to the misleading examination findings and complicated the initial diagnostic assessment. <br> <br>This case also highlights the utility of point-of-care ultrasound in the evaluation of superficial knee structures and the rapid diagnosis of patellar tendon injuries.1 Additionally, the successful outcome following platelet-rich plasma treatment and structured rehabilitation adds to the limited literature regarding nonoperative management of high-grade partial patellar tendon tears (2).

Editor's Comments:
This case serves as a reminder to avoid diagnostic anchoring in acute knee injuries, particularly when examination findings and injury mechanism appear to support more common ligamentous or meniscal pathology. Targeted imaging may help identify less common extensor mechanism injuries. While leukocyte-poor platelet-rich plasma was used successfully in this case, ultrasound-guided percutaneous needle tenotomy may represent an alternative or adjunctive minimally invasive treatment option for selected high-grade partial patellar tendon tears (3).

References:
1) Karlsson J, Kälebo P, Goksör LA, Thomée R, Swärd L: Partial rupture of the patellar ligament. Am J Sports Med 1992;20:390-395 <br> <br>2) Golman M, Wright ML, Wong TT, et al. : Rethinking patellar tendinopathy and partial patellar tendon tears: A novel classification system. Am J Sports Med 2020;48:359-369 <br> <br>3) Housner JA, Jacobson JA, Misko R. Sonographically guided percutaneous needle tenotomy for the treatment of chronic tendinosis. J Ultrasound Med. 2009 Sep;28(9):1187-92.

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