X-rays and scans can fail to differentiate hip pathology from lumbar spinal stenosis: Two case reports

Abstract

Background: Occasionally, hip pathologies may present alone or combined with lumbar spine pathology, especially lumbar stenosis. Although the history and clinical examination may help differentiate between the two, hip X-rays alone without accompanying magnetic resonance imaging (MRI) studies may prove unreliable.

Case descriptions: Case 1 - A 72-year-old male presented with the sudden onset of severe back and left posterior thigh pain. Straight leg raising test was positive at 70° (right) and 60° (left), and he had left lower extremity numbness and weakness. The lumbar MRI showed L5-S1 spinal stenosis. Although X-rays of both hips were negative, the MRI showed bilateral femoral neck fractures. He underwent screw fixation of the hip fractures and later underwent endoscopic decompression of the spinal stenosis. Case 2 - A 35-year-old male presented with low backache and right hip pain of 1 month's duration. The neurological examination was normal, except for positive straight leg raising bilaterally at 60°. The spine MRI was normal. However, despite negative X-ray of both hips, the hip MRI revealed avascular necrosis (AVN) of both femoral heads requiring subsequent orthopedic management.

Conclusion: Hip pathology may mimic lumbar spinal stenosis. In the two cases presented, plain X-rays failed to document hip fractures (case 1) and AVN (case 2), respectively, both of which were later diagnosed on MRI studies.

Keywords: Avascular necrosis; Backache; Femoral head; Fracture; Hip; Neck of femur; Spinal stenosis; Spine.

Figure 1:

(Case 1) Preoperative anteroposterior X-ray of pelvis with both hips showing normal hip joint and femoral necks.

Figure 2:

(Case 1) Magnetic resonance imaging showing fracture of the neck of both femurs (a) magnetic resonance imaging and (b) computed tomography.

Figure 3:

(Case 1) Postoperative anteroposterior X-ray of both hip joints showing cannulated cancellous screw fixation of both the femoral necks.

Figure 4:

(Case 2) Initial anteroposterior X-ray showing normal hip joints.

Figure 5:

(Case 2) Magnetic resonance imaging of both hips showing avascular necrosis of both femoral heads (a) T1 coronal and (b) T2 coronal.