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431 - Femoral Neuropathy after Total Knee Arthroplasty: A Case Report

Thursday, February 27, 2025

5:00 PM - 6:30 PM MST

Presenting Author(s)

HA

Haris Arshad, DO

Resident Physician
Marianjoy Rehabilitation Hospital
Chicago, Illinois, United States

Co-Author(s)

SA

Sung Ahn, DO

Attending Physician
Edward Hines Jr. Veterans Administration Hospital
Hines, Illinois, United States

Case Diagnosis: A 46-year-old obese female presented with left leg weakness and paresthesia after a left total knee arthroplasty (TKA), without bowel or bladder incontinence. An electrophysiologic study revealed a subacute, incomplete left femoral neuropathy.

Case Description: A patient developed persistent left leg weakness, paresthesia, and restricted knee range of motion following a left total knee arthroplasty (TKA). Despite comprehensive rehabilitative therapy, she required knee manipulation three months postoperatively due to limited progress. Her surgery included a 93-minute tourniquet application at 250 mmHg. Exam findings revealed 2/5 strength in left hip flexion, 1/5 in knee extension, and diminished sensation along the left anterior medial leg. Initial nerve conduction studies showed low amplitude and prolonged latency in the left femoral motor response, while needle examination identified fibrillation potentials in the vastus medialis and lateralis, with minimal voluntary motor activity. These findings suggested a subacute, incomplete, left femoral neuropathy. A follow-up electrophysiologic study one year later indicated improved left femoral motor compound muscle action potential amplitude and distal latency, reflecting recovery in the femoral neuropathy.

Discussions: Tourniquet-induced femoral neuropathy, though rare after TKA, has been associated with prolonged tourniquet times and pressure. Literature suggests an increased risk of a nerve injury in these situations, emphasizing the need for cautious monitoring and early intervention. Given the incomplete nature of the nerve injury, further symptom improvement and recovery remain possible. The electrophysiologic study provided a pivotal role in both diagnostic and prognostic value.

Conclusions:

This case highlights a femoral neuropathy as a potential complication of TKA, particularly in cases involving extended tourniquet use and high pressure. Recognition of these risks can lead to earlier diagnosis and management, thereby improving outcomes and aiding in long-term recovery.