title: Open wedge high tibial osteotomies: Calcium-phosphate ceramic spacer versus autologous bonegraft.
abstract: BACKGROUND
  Valgus tibial osteotomy (VTO) is a well-known procedure for the treatment of medial compartment femoro-tibial osteoarthritis. Good and very good results have been reported with calcium phosphate wedges, which avoid the inconveniences of autologous grafts use. The hypothesis of this study is that with equivalent results in the treatment of osteoarthritis of the knee, the use of calcium phosphate wedges (BMCaPh) to fill the bone defect created by osteotomy would result in fewer specific complications and less pain associated with autologous grafts (AUTO) harvesting.
  
  
  METHODS
  This prospective, controlled, randomised study included one arm that received a macroporous, biphasic calcium phosphate wedge (BMCaPh group) and one arm that received an autologous tricortical graft (AUTO group) for filling. The same plate with locked screws was used for fixation in all cases. All patients underwent at least two years of clinical and radiographic post-operative follow-up.
  
  
  RESULTS
  Forty patients were included. Loss of correction occurred in six of the twenty-two patients in the BMCaPh group (27%), resulting in three early surgical revisions, compared to one loss of correction in the AUTO group. Lateral cortical hinge tears were a risk factor for loss of correction for the entire cohort and in the BMCaPh group. (relative risk 13.3 [1.9-92]. Moreover, union took significantly longer and pain lasted significantly longer in the BMCaPh group, although results were comparable at 6 months.
  
  
  CONCLUSIONS
  A significant number of undesirable events (loss of correction) occurred in this study, limiting the number of included patients. Nevertheless, the results show that although there was no difference in the two groups for overall complications, number of revisions all causes combined, or clinical results, filling with BMCaPh was less tolerated and increased the risk of loss of correction when local mechanical conditions of the knee were unfavourable (lateral cortical hinge tears). Moreover, although it is not possible to draw a conclusion because of methodology bias in this study, early weight-bearing resumption on the knee also seemed to favour these complications.
  
  
  METHODS
  Level II. Prospective randomized study.
authors.affiliation: Orthopaedic surgery and traumatology Clinic, Musculo-skeletal Department, Hôtel-Dieu Teaching Medical Center, 1, place A.-Ricordeau, 44093 Nantes cedex, France. fgouin@chu-nantes.fr
authors.forename: F
authors.initials: F
authors.lastname: Gouin
authors.forename: F
authors.initials: F
authors.lastname: Yaouanc
authors.forename: D
authors.initials: D
authors.lastname: Waast
authors.forename: B
authors.initials: B
authors.lastname: Melchior
authors.forename: J
authors.initials: J
authors.lastname: Delecrin
authors.forename: N
authors.initials: N
authors.lastname: Passuti
mesh_terms: D000328:Adult; D000368:Aged; D001672:Biocompatible Materials; D017760:Bone Malalignment / Q000601:surgery*; D018786:Bone Substitutes; D016025:Bone Transplantation; D002130:Calcium Phosphates; D002516:Ceramics; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D012307:Risk Factors; D013977:Tibia / Q000601:surgery*
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; C485829:calcium phosphate, dibasic, anhydrous