Clinical outcomes in relation to locations of bone marrow edema lesions in patients with a subchondral insufficiency fracture of the hip: a review of fifteen cases

Abstract

Objective: The prognosis of patients with a subchondral insufficiency fracture remains unclear. The purpose of this study was to investigate the correlation between locations of bone marrow edema (BME) lesions and clinical outcome in patients with a subchondral insufficiency fracture of the hip.

Methods: We retrospectively reviewed 15 consecutive hips in 14 patients who were diagnosed with subchondral insufficiency fracture of the hip at our institution between April 2013 and September 2014. This study included five males (six hips) and nine females (nine hips), ranging from 36 to 83 years of age (mean age: 66 years). The mean duration from the onset of hip pain to MRI examination was 1.8 months (range 0.5-5 months). Both clinical and imaging findings were investigated.

Results: Based on the findings of MR images, BME lesion in the femoral head alone was observed in six patients (six hips), BME lesion in the acetabulum alone was observed in one patient (two hips) and BME lesions in both the femoral head and acetabulum were observed in seven patients (seven hips). 3 of 15 hips resulted in rapidly destructive arthrosis and their BME lesions were observed in both the femoral head and acetabulum. 8 of 15 hips successfully healed by conservative treatment and BME lesions in 7 of these 8 hips were observed in only the femoral head or acetabulum.

Conclusion: The results of this study indicate that the locations of BME lesions (femoral side alone, acetabular side alone or both) may be related to the clinical outcome in patients with a subchondral insufficiency fracture of the hip.

Advances in knowledge: Patients with subchondral insufficiency fracture of the hip in whom BME lesions were observed in both the femoral head and acetabulum may have a higher risk to need to undergo total hip arthroplasty.

Figure 1.

An 83-year-old male (Patient no. 1 in Tables 1 and 2): (a) an anteroposterior (AP) radiograph of the right hip at the onset of pain. (b) On the coronal T₁ weighted image [repetition time (TR)/echo time (TE) = 474/14 ms], a low-intensity band is observed beneath the articular cartilage at the superolateral portion of the femoral head (arrows). (c) On the coronal T₂ fat-saturated image (TR/TE = 3500/87), bone marrow edema lesion is observed at the anterior portion of the acetabulum (arrow). (d) 3 months after onset, an AP radiograph is showing the progressive collapse of the femoral head and disappearance of the joint space. (e) A cut section of the resected femoral head is showing a reddish and whitish linear shaped area beneath the articular cartilage (arrows). (f) A photomicrograph obtained from the collapsed region [reddish and whitish linear shaped area in (e)]. Fracture callus (arrows), reactive cartilage and granulation tissue are observed. Granulomatous foci of fragmented bone and cartilage debris (arrowheads) are seen in the bone marrow space, indicating rapid joint destruction (haematoxylin and eosin X40).

Figure 2.

A 78-year-old male (Patient no. 10 in Tables 1 and 2): (a) an anteroposterior radiograph of the bilateral hip at the onset of pain. (b, c) MRI findings at the onset of pain. A coronal T₁ weighted image [repetition time (TR)/echo time (TE) = 430/14] (b) is demonstrating diffuse low signal intensity in the acetabulum and a corresponding high signal intensity on the fat-saturated T₂ image (TR/TE = 3800/90) (c). (c) A fracture line is observed beneath the articular cartilage at the left side of acetabulum (arrows). (d) 3 weeks after the onset of pain, patchy areas of osteosclerosis are seen in the acetabulum (arrows). (e, f) MRI findings 3 months after the onset of pain (T₁ weighted image, TR/TE = 550/10; fat-saturated T₂ image, TR/TE = 5000/82). Bone marrow edema lesions have decreased and the low-intensity band previously seen in (c) has disappeared (f).