There is still controversy whether transient
osteoporosis of the hip joint represents a distinct self-limiting disease, or reflects only an early, reversible subtype of non-traumatic
osteonecrosis (ON). Transient
osteoporosis has several synonyms:
algodystrophy of the hip; transient marrow oedema; or bone marrow oedema syndrome--BMOES. Clinical presentation of BMOES shows mechanical hip joint
pain, ON risk factors, and a diffuse bone marrow oedema in MR imaging. Histomorphological changes resemble early ON, but with diffuse sufficient repair in BMOES and focal and insufficient repair only at the border of the necrotic lesion in ON. Therefore the
clinical course and outcome are significant different, with restitution occurring in BMOES, while progressive destruction of the joint takes place in ON. So far, the preferred treatment strategies are protected weight bearing for BMOES, but operative treatment for ON. In a prospective study of patients with BMOES, the clinical, radiographic, and MRI course of 43 hip joints after core
decompression treatment were investigated. All patients showed immediate relief of
pain after surgery and the average duration of symptoms with
conservative treatment could be dramatically reduced by core
decompression from 6 months down to 2 months. There were no perioperative complications. Based on our experience with over 100 BMOES patients, we are convinced that this syndrome represents not a distinct disease but an early reversible subtype of non-traumatic ON. Due to the excellent clinical results of core
decompression, we recommend this operative therapeutical concept in patients with painful BMOES.