Disclosures: Daniel Giangrasso, DO: No financial relationships or conflicts of interest

Case Description: Acute pain and foot drop began after crossing right leg over left leg for ninety minutes. Physical examination notable for tenderness on the lateral joint line and posterolateral corner of the knee, and complete absence of dorsiflexion and toe extension strength with associated right steppage gait. MRI of right knee notable for popliteus tendon insertional tendinosis with longitudinal split tear and edema/active inflammation, and a ruptured baker’s cyst. Aspiration of baker’s cyst did not provide immediate relief of pain or improvement in foot drop. 5 cc of blood was aspirated. EMG positive for isolated acute denervation of TA and EHL consistent with isolated deep fibular nerve injury. Ultrasound and fluoroscopy-guided injection of peritendinous PRP was performed at the insertion of right popliteus muscle. Patient was given E-STIM unit which was pre-programmed for foot drop. Post-injection protocol included physical therapy and avoidance of anti-inflammatory medications.

Setting: Multispecialty private practice

Patient: 40 year old male with right knee pain and acute right foot drop. Assessment/

Results: At 2 weeks post-PRP injection plus physical therapy, the patient reported improvement in pain but still had weakness with ankle dorsiflexion and great toe extension. At 8 weeks, the patient’s pain and dorsiflexion and toe extension weakness completely resolved. Patient was able to compete in his athletic competition.

Discussion: This is the first reported case, to our knowledge, of popliteus tendon tear contributing to acute fibular nerve palsy. A ruptured popliteus tendon with ruptured baker’s cyst may have caused fibular nerve compression by a hematoma in the popliteal fossa. Direct compression of fibular nerve while crossing his legs likely contributed to acute drop also.

Conclusion: Acute right foot drop can be multifactorial. Aspiration of hematoma, and soft tissue repair with PRP led to complete resolution of symptoms. A review of the literature regarding posterolateral knee structures causing acute nerve palsy will be discussed.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/platelet-rich-plasma-injection-to-popliteus-tendon-tear-in-young-male-with-acute-fibular-nerve-palsy-a-case-report-and-review-of-the-literature/