In a 62‑year‑old woman with left lateral hip pain radiating down the leg to the foot and left foot numbness and tingling, what is the most likely diagnosis and appropriate initial management?

L3 Radiculopathy: Most Likely Diagnosis

This 62-year-old woman most likely has L3 radiculopathy, and the appropriate initial management is lumbar spine MRI without contrast followed by conservative therapy with NSAIDs, activity modification, and physical therapy for 6-12 weeks unless red flags develop. 1, 2

Clinical Reasoning for L3 Radiculopathy

The presentation is classic for L3 nerve root compression rather than primary hip pathology:

• Dermatomal sensory loss along the medial lower leg (numbness and tingling in the left foot) is the defining feature of L3 radiculopathy and distinguishes it from intra-articular hip disease 1, 2

• The pain distribution—lateral hip radiating down to the foot—follows the L3 dermatome pattern, which includes buttock, lateral hip, anterior-lateral thigh, and extends to the medial lower leg 2, 3, 4

• L3 radiculopathy characteristically presents with thigh pain and hip/knee pain in elderly patients, with sensory disturbance being more common than motor weakness 4

• Research shows that L3 radiculopathy patients report symptoms at the upper buttock, ventral surface of thighs, knees, and upper ventral surface of legs, matching this patient's presentation 3

Key Diagnostic Steps

Immediate Clinical Assessment

• Perform hip-specific maneuvers (FABER and FADIR tests)—negative results effectively exclude intra-articular hip pathology as the primary source 1, 2

• Document the exact dermatomal pattern of sensory loss, particularly along the medial lower leg, which is pathognomonic for L3 2, 3

• Assess for motor weakness in hip flexion and knee extension (L3 myotome), though motor deficits are less common than sensory changes in L3 radiculopathy 4

• Note that the straight-leg-raise test is insensitive for upper lumbar (L3) radiculopathy—a negative test does not exclude the diagnosis 1, 2

First-Line Imaging

Lumbar spine MRI without contrast is the mandatory first-line imaging study to evaluate for disc herniation, foraminal stenosis, or other compressive pathology at the L3 nerve root level 1, 2

• MRI provides superior visualization of nerve root compression compared to all other modalities 2, 5

• Plain radiographs of the lumbar spine may be obtained first if structural abnormalities are suspected, but MRI is superior for identifying nerve compression 2

Initial Management Algorithm

Conservative Treatment (First 6-12 Weeks)

Begin with conservative management unless progressive neurologic deficits or red flags are present: 2, 5

• NSAIDs for pain control—naproxen 375-500 mg twice daily is effective for radicular pain 2, 6

• Activity modification—avoid positions or activities that exacerbate radicular symptoms 2

• Physical therapy—though evidence for effectiveness is controversial, it remains a standard component of conservative care 5

• Monitor for 6-12 weeks for spontaneous resolution, which occurs in more than 50% of cases 7

Escalation Criteria

Proceed to interventional or surgical management if: 2, 5

• Progressive neurologic deficit develops (increasing motor weakness or sensory loss) 2

• Failure of conservative management after 6-12 weeks of appropriate treatment 2

• Severe refractory pain that significantly impairs function 5, 7

Interventional Options

• Epidural steroid injection under fluoroscopic or CT guidance at the L3 level may provide both diagnostic confirmation and therapeutic benefit if conservative measures fail 2, 5

• Transforaminal epidural steroid injection can achieve significant and lasting pain relief in subacute lumbosacral radicular pain 5, 7

• Selective nerve root injection was completely effective in 10 of 17 patients with L3 radiculopathy in one case series 4

Surgical Referral

Neurosurgical or spine surgery consultation is indicated for: 2, 5

• Progressive neurological deficits despite conservative care 2
• Severe pain refractory to conservative and interventional management 5
• Documented nerve root compression on MRI with concordant clinical findings 5

Critical Diagnostic Pitfalls

Common Misdiagnoses in L3 Radiculopathy

Four of 17 patients with L3 radiculopathy in one series were initially misdiagnosed and received inappropriate conservative treatment for hip and/or knee joint diseases 4. This highlights the importance of:

• Always considering L3 radiculopathy in elderly patients with lower limb pain who do not respond to treatment for hip or knee joint diseases 4

• Recognizing that L3 radiculopathy can present with various lower limb pain patterns, not just classic dermatomal distribution 4

• Understanding that hip arthritis typically causes lateral hip/thigh aching without dermatomal sensory loss, which differs from L3 radiculopathy 1

Age-Related Considerations

• The average age of L3 radiculopathy patients is 76 years, making this diagnosis particularly relevant in older adults 4

• Associated spinal diseases include lumbar canal stenosis, extraforaminal stenosis, and disc herniation—all common in this age group 4

• Four patients in one series were nonambulatory because of severe L3 radicular pain, emphasizing the potential severity 4

Why Not Primary Hip Pathology?

While hip pathology must be considered in any patient with lateral hip pain, several features argue against it as the primary diagnosis:

• The presence of dermatomal sensory loss (foot numbness/tingling) is not explained by hip pathology 1, 2

• Radiation to the foot is atypical for primary hip disease, which usually causes anterior hip/groin pain or lateral hip/thigh aching 8, 1

• If hip-specific tests (FABER, FADIR) are negative, intra-articular hip disease is effectively excluded 1, 2

That said, if clinical suspicion for hip pathology remains high or if lumbar spine imaging is unrevealing, obtain AP pelvis and frog-leg lateral hip radiographs as a screening tool 8, 1. If radiographs are negative and hip pathology is still suspected, MRI of the hip without contrast can detect occult fractures, osteonecrosis, or soft tissue pathology 8, 1.