title: Conversion of hip fusion to total hip arthroplasty: clinical, radiological outcomes and complications in 40 hips.
abstract: OBJECTIVE
  The purpose of this retrospective study is to report the clinical and radiological outcome of total hip arthroplasty in patients with previous hip arthrodesis.
  
  
  METHODS
  We retrospectively reviewed 28 (40 hips) prospectively followed patients in whom ankylosed hips were converted to total hip arthroplasty (THA) between 2010 and 2014 in our institution. The average age at the time of the conversion operation was 40.8 ± 9.8 years (range 24-62). The ankylosis had lasted 20.4 ± 13.0 years (range 3-56) before conversion surgery. The etiology of the ankylosis was septic arthritis in 10 (25%), post-traumatic hip osteoarthritis in 8 (20%), developmental hip dysplasia in 6 (15%), rheumatoid arthritis in 6 (15%), primary osteoarthritis in 5 (12.5%) and ankylosing spondylitis in 5 (12.5%) hips. The indications for arthroplasty were intractable low back pain in 14 (50%), hip pain in 24 (85.7%), and ipsilateral knee pain in 19 (67.8%) patients. Harris Hip Score (HHS) was used to rate the clinical results before and after the surgery. Radiographic evaluations included component malposition and loosening. All complications during the study period were recorded.
  
  
  RESULTS
  The mean follow-up period was 39.9 ± 10.6 months (range 24-60). The mean preoperative HHS was 33.3 ± 8.6 (range 18-50) and the mean HHS at the final follow-up was 74.9 ± 8.6 (range 52-97). There was a statistically significant increase in HHS (p = 0.0001). HHS was excellent in 1, good in 6, fair in 14 and poor in 7 patients. Increase in HHS was lower than 20 points in one patient (18 points), and one patient required two-staged exchange procedure due to deep infection. Thus, according to our success criteria (increase in HHS more than 20 points, radiographically stable implant, and no further surgical reconstruction), 92.8% (26/28) of patients had benefit from the surgery. Trendelenburg sign was positive in 12 hips. There was limb length inequality in 11 patients (mean 0.5 cm, range 1-3 cm). No patients had heterotopic ossification, sciatic nerve palsy or dislocation. There were five intra-operative fractures of the greater trochanter that were treated with cable wiring. One patient had trochanteric avulsion injury and was treated with trochanteric grip and cables. One patient (2.5%) had deep infection one year after the conversion THA and was treated with two-staged exchange procedure.
  
  
  CONCLUSIONS
  Conversion hip arthroplasty is an effective treatment method which provides functional recovery and patient satisfaction. However, a proper surgical technique and planning is necessary to minimize the complications.
authors.affiliation: Orthopedics and Traumatology Clinic, Ortopedia Private Hospital, Adana, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Celiktas
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Soguksu Mah. Kazım Karabekir cd. Muratpaşa, Antalya, Turkey. drozkankose@hotmail.com.
authors.forename: Ozkan
authors.identifier: http://orcid.org/0000-0002-7679-9635
authors.initials: O
authors.lastname: Kose
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Soguksu Mah. Kazım Karabekir cd. Muratpaşa, Antalya, Turkey.
authors.forename: Adil
authors.initials: A
authors.lastname: Turan
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Soguksu Mah. Kazım Karabekir cd. Muratpaşa, Antalya, Turkey.
authors.forename: Ferhat
authors.initials: F
authors.lastname: Guler
authors.affiliation: Orthopedics and Traumatology Clinic, Ortopedia Private Hospital, Adana, Turkey.
authors.forename: Cagri
authors.initials: C
authors.lastname: Ors
authors.affiliation: Orthopedics and Traumatology Clinic, Ortopedia Private Hospital, Adana, Turkey.
authors.forename: Emre
authors.initials: E
authors.lastname: Togrul
mesh_terms: D000328:Adult; D000844:Ankylosis / Q000150:complications / Q000209:etiology / Q000601:surgery*; D018771:Arthralgia / Q000209:etiology / Q000601:surgery; D001174:Arthrodesis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007717:Knee / Q000503:physiopathology; D017116:Low Back Pain / Q000209:etiology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011859:Radiography; D020127:Recovery of Function; D016896:Treatment Outcome
keywords: Conversion hip arthroplasty; Hip arthrodesis; Hip fusion; Total hip arthroplasty