Evaluation of Trendelenburg Gait in the Context of L4 Radiculopathy

Anatomical Considerations

The superior gluteal nerve originates from the L4, L5, and S1 nerve roots, so isolated L4 radiculopathy alone cannot produce the degree of hip‑abductor weakness required for a Trendelenburg gait. 1

Hip‑abductor weakness is most often associated with hip joint disease (e.g., acetabular dysplasia, femoroacetabular impingement), postoperative complications after total hip arthroplasty, or direct gluteal tendon tears rather than with isolated L4 radiculopathy. 1

Coexisting gluteus medius or minimus tendon tears (hip‑abductor tendon pathology) should be considered as a cause of Trendelenburg gait in patients who also exhibit L4 radiculopathy symptoms. 1
Direct injury to the superior gluteal nerve, involving its L4‑L5‑S1 contributions, is another plausible explanation for a Trendelenburg gait accompanying L4 radiculopathy findings. 1

If a Trendelenburg sign is present, magnetic resonance imaging or ultrasound of the hip should be obtained to evaluate for gluteal tendon pathology. 1

The detection of a Trendelenburg gait modifies the management algorithm for presumed L4 radiculopathy, requiring assessment of both the hip abductors and the lumbosacral plexus to determine appropriate therapeutic strategies. 1

Radicular pain follows the L4 dermatome, typically radiating from the lower back through the anterior and medial thigh to the medial aspect of the lower leg and foot, according to the American College of Physicians 2
The pain has a neuropathic character with dysesthesia, burning, or electric sensations that distinguish it from mechanical back pain, as noted by the American College of Radiology 3

Diminished knee strength on examination is characteristic and helps localize the lesion to L4, as reported by the American College of Physicians 4
Diminished or absent patellar (knee jerk) reflex is the primary reflex abnormality, as this reflex is mediated by the L3-L4 nerve roots, according to the American College of Physicians 4

Imaging findings do not always correlate with symptoms, as disc abnormalities are common in asymptomatic patients, as noted by the American College of Radiology 5, 6
MRI is the preferred imaging modality for confirming nerve root compression when patients fail conservative management or are surgical candidates, according to the American College of Radiology 5, 6
Electrodiagnostic studies should be used to confirm the clinical diagnosis and differentiate radiculopathy from plexopathy or peripheral nerve lesions, as recommended by the American College of Radiology 3

Pain radiating from the lower back to the lateral thigh and anterolateral leg is most commonly caused by L4 nerve root compression. 7

Diminished quadriceps (knee‑extension) strength is the hallmark motor deficit that localizes the lesion to the L4 root. 7
Diminished or absent patellar (knee‑jerk) reflex is the primary reflex abnormality, reflecting involvement of the L3‑L4 nerve roots. 7

The straight‑leg‑raise test demonstrates a sensitivity of 91 % but a specificity of only 26 % for detecting a herniated disc that produces radiculopathy. 7

Over 90 % of symptomatic lumbar disc herniations occur at the L4/L5 and L5/S1 intervertebral levels, making L4 nerve‑root compression a frequent cause of the described symptom pattern. 7