(Kiosk 2) Leg Extension Weakness After Electrical Injury: A Case Report

Case Diagnosis: Right knee ligament, tendon, and cartilage injury.

Case Description or Program Description: Patient is a 34-year-old male who presents for initial evaluation of right knee buckling and pain after electrical injury while intoxicated with subsequent loss of consciousness, superficial partial thickness to the volar hands, rhabdomyolysis, and acute kidney injury. Two months later, the patient has returned to work full-time as a waiter, however, he reports frequent falls from leg weakness.

Setting: Outpatient

Assessment/Results: Physical examination significant for hip flexion and knee extension weakness on the right. Complete knee extension possible with gravity eliminated. Sensation is intact. Right patella reflex could not be elicited. MRI significant for multiple tendinous and cartilaginous injury of the right leg including high-grade partial thickness tear of the patellar tendon, tendinosis of distal quadriceps tendon, high-grade partial thickness tear of the ACL, medial and lateral meniscal tear, and right paralabral cyst suggestive of labral tear.

Discussion (relevance): Electric current flows through the pathway of least resistance and is therefore easily transmitted in tissues such as nerves, blood vessels, and muscles. Tissues with higher resistance, such as tendons, fat, and bones, generate more heat due to its impediment of electric flow and are therefore more susceptible to thermal injury. In this patient, pathophysiology is likely thermal due to the lower cross-sectional area and increased tissue resistance at the knee joint. We also theorize that the patient may have sustained electricity-induced muscle tetany leading to forceful concentric quadriceps activation and subsequent diffuse tissue injury at the knee extensor mechanism.

Conclusions: Musculoskeletal injuries due to electricity are rare and are more likely to involve the upper extremities due to the natural conduction of current through the body. To our knowledge, this is the first case report documenting extensive lower extremity musculoskeletal injuries as a result of electrical injury. Prompt, accurate diagnosis is valuable for initiation of rehabilitation measures and reduce long-term morbidity.