title: Healing Process of Osteonecrotic Lesions of the Femoral Head Following Transtrochanteric Rotational Osteotomy: A Computed Tomography-Based Study.
abstract: BACKGROUND
  Transtrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT).
  
  
  METHODS
  Among 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans.
  
  
  RESULTS
  Plain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p= 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p= 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area.
  
  
  CONCLUSIONS
  The majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Devendra
authors.initials: D
authors.lastname: Lakhotia
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Siva
authors.initials: S
authors.lastname: Swaminathan
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Won Yong
authors.initials: WY
authors.lastname: Shon
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Jong Keon
authors.initials: JK
authors.lastname: Oh
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Jun Gyu
authors.initials: JG
authors.lastname: Moon
authors.affiliation: Department of Orthopedic Surgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Chirayu
authors.initials: C
authors.lastname: Dwivedi
authors.affiliation: Department of Radiology, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Suk Joo
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D000293:Adolescent; D000328:Adult; D001861:Bone Regeneration; D005260:Female; D005270:Femur Head / Q000502:physiology*; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014945:Wound Healing; D055815:Young Adult
keywords: Computed tomography; Femur head necrosis; Osteotomy; Repair