Trendelenburg Gait in L4 Radiculopathy
Trendelenburg gait is NOT a typical finding in L4 radiculopathy and should prompt consideration of alternative diagnoses, particularly hip abductor pathology or superior gluteal nerve injury. 1
Clinical Presentation of L4 Radiculopathy
L4 radiculopathy presents with a characteristic pattern that does not include Trendelenburg gait:
- Pain distribution: Radicular pain follows the L4 dermatome, radiating from the lower back through the anterior and medial thigh to the medial aspect of the lower leg and foot 1
- Motor deficits: Diminished knee extension strength (quadriceps weakness) is the hallmark motor finding that helps localize the lesion to L4 1
- Reflex changes: Diminished or absent patellar (knee jerk) reflex is the primary reflex abnormality, as this reflex is mediated by the L3-L4 nerve roots 1
- Sensory findings: Sensory loss in the painful dermatome occurs in approximately 56% of cases 2
Why Trendelenburg Gait is Not Expected
Trendelenburg gait results from hip abductor weakness (gluteus medius and minimus), which are innervated by the superior gluteal nerve (L4-L5-S1 nerve roots), not the L4 nerve root alone. 3, 4
- The superior gluteal nerve arises from multiple nerve roots (L4, L5, and S1), making isolated L4 radiculopathy insufficient to cause significant hip abductor weakness 3
- Trendelenburg gait manifests as contralateral pelvic drop during single leg stance, which requires substantial hip abductor dysfunction 4
- Hip abductor pathology is more commonly associated with hip joint disease (acetabular dysplasia, femoroacetabular impingement), post-surgical complications after total hip arthroplasty, or direct gluteal tendon tears 3, 4
Differential Diagnosis When Trendelenburg Gait is Present
If a patient presents with both L4 radiculopathy symptoms and Trendelenburg gait, consider:
- Lumbosacral plexopathy rather than isolated radiculopathy, which can affect multiple nerve roots including the superior gluteal nerve 1
- Hip abductor tendon pathology: Gluteus medius or minimus tendon tears can coexist with lumbar pathology 3
- Superior gluteal nerve injury: Direct nerve injury affecting L4-L5-S1 contributions 3
- Multiple level radiculopathy: Involvement of L4, L5, and S1 nerve roots simultaneously 5
Diagnostic Approach
When clinical findings don't match the expected pattern for L4 radiculopathy:
- MRI lumbosacral plexus with and without IV contrast should be obtained to differentiate radiculopathy from plexopathy 1
- Electrodiagnostic studies (EMG/NCS) are essential to confirm the clinical diagnosis and differentiate radiculopathy from plexopathy or peripheral nerve lesions 1, 2
- Hip imaging (MRI or ultrasound) may be warranted to evaluate for gluteal tendon pathology if Trendelenburg sign is present 3
Management Implications
For true L4 radiculopathy without red flags:
- Conservative management for 4-6 weeks is appropriate, as the natural history shows improvement in the majority of patients 6
- MRI lumbar spine without IV contrast should only be obtained after 6 weeks of failed conservative management if the patient is a potential candidate for surgery or epidural steroid injection 6, 1
- Immediate imaging is indicated only with severe or progressive neurological deficits, suspected cauda equina syndrome, or suspicion of underlying serious conditions (infection, malignancy) 6
If Trendelenburg gait is present, the management algorithm changes significantly because this suggests pathology beyond simple L4 radiculopathy and requires evaluation of the hip abductors and lumbosacral plexus 3, 1.