The Role of Hip Arthroscopy in the Evaluation of Avascular Necrosis

Abstract

This prospective study evaluated the correlation between plain radiographs, magnetic resonance imaging (MRI), and diagnostic arthroscopy in the staging of avascular necrosis of the femoral head. Fifty-two hips in 46 patients were prospectively staged using radiographic and MRI staging systems. Patients subsequently underwent hip arthroscopy to visualize the articular surface prior to considering salvage of the femoral head and debride delaminated osteochondral fragments. Weighted Kappa analysis revealed only moderate correlation between MRI and plain radiographs (κ=.11), MRI and arthroscopy (κ=.21), and plain radiographs and arthroscopy (κ=.19). Six (46%) of 13 patients with a radiographically apparent subchondral fracture demonstrated collapse of the articular surface at arthroscopy. Four (24%) of 17 hips with >2 mm of collapse of the femoral head on plain radiographs demonstrated fragmentation of the osteochondral surface of the femoral head at arthroscopy. In 5 patients with flattening of the femoral head, 3 patients had delamination of both the femoral and acetabular surfaces. In regard to labral pathology, 5 of 22 post-collapse hips also had large bucket handle tears of the labrum. Arthroscopy of the hip revealed osteochondral degeneration that was not detected by plain radiographs or MRI in 36% of post-collapse femoral heads.

Evolutionary course of the femoral head osteonecrosis: Histopathological - radiologic characteristics and clinical staging systems

“…Ruch et al. presented poor correlation between radiographic and arthroscopic assessment of femoral head cartilage in patients with early post-collapse osteonecrosis, as arthroscopic evaluation revealed osteochondral lesions that had not been noted on radiograph or MR [ 56 , 57 ]. Mukisi-Mukaza et al.…”

Relationship between the degree of subchondral collapse and articular surface irregularities in osteonecrosis of the femoral head

“…Furthermore, the time from pain onset to surgery was longer in femoral heads with articular surface irregularities than in those without such irregularities. Previous studies involving hip arthroscopy also showed articular cartilage degeneration in postcollapse ONFH that was not detectable on plain radiographs or MRI 10,11,42 . Therefore, earlier joint‐preserving surgery could be desirable because it can lead to satisfactory results, such as effectively preserving hip joints and preventing progression of subchondral collapse 43,44 …”

“…Severe subchondral collapse causes severe articular surface irregularities 8,9 . However, some necrotic femoral heads with radiological evidence of subchondral collapse have no gross abnormalities of the articular surface 10,11 . The degree of articular surface irregularities is expected to be related to the degree of subchondral collapse; however, there have been no reports evaluating this relationship.…”

“…8,9 However, some necrotic femoral heads with radiological evidence of subchondral collapse have no gross abnormalities of the articular surface. 10,11 The degree of articular surface irregularities is expected to be related to the degree of subchondral collapse; however, there have been no reports evaluating this relationship. Since articular surface irregularities are not easily captured on clinical images, a meaningful cutoff value for how the degree of subchondral collapse relates to articular surface irregularities would be useful when considering the indications for joint-preserving surgery.…”

Arthroscopy of the hip in children and adolescents

“…Ruch et al [46] reported on the use of arthroscopy of the hip in avascular necrosis and developed a staging classification for the feasibility of performing a revascularization procedure. Kloen [47] noted anterosuperior flattening of the femoral heads which reduced the head neck ratio leading to cam impingement.…”