title: Bovine xenograft locking Puddu plate versus tricalcium phosphate spacer non-locking Puddu plate in opening-wedge high tibial osteotomy: a prospective double-cohort study.
abstract: OBJECTIVE
  The aim of the study was to compare clinical and radiographic outcomes of opening-wedge high tibial osteotomy (HTO) augmented with either xenograft or tricalcium phosphate spacer for the management of medial compartment osteoarthritis (OA) with genu varum.
  
  
  METHODS
  Between 2004 and 2007, we prospectively enrolled 52 patients with medial compartment knee OA who underwent opening-wedge HTO fixed with locking Puddu plate and xenograft (n = 26) or non-locking Puddu plate and tricalcium phosphate spacer (n = 26). The alignment of the lower limb was assessed by measuring the hip-knee-ankle (HKA) angle. Clinical outcomes were assessed with the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, SF-36 and European Quality of Life-5 Dimensions scale. All patients were followed up at six weeks and at three, six, 12 and 24 months post-operatively. Clinical outcomes were assessed preoperatively and at 24 months post-operatively.
  
  
  RESULTS
  All clinical scores improved significantly in both groups after surgery, without any significant difference between the two groups. Immediately after surgery, the HKA angle went from 9.1 ± 5.2° in varus to 3.1 ± 4.8° in valgus (P = 0.01) in the xenograft group, and from 8.5 ± 5.9° in varus to 3.4 ± 4.2° in valgus (P = 0.01) in the tricalcium phosphate group. At the last follow-up, the tricalcium phosphate group showed a significant loss of correction (P = 0.03).
  
  
  CONCLUSIONS
  HTO performed with xenograft locking plate and tricalcium phosphate non-locking plate constructs showed good clinical outcomes. However, the xenograft locking plate construct is superior to the tricalcium phosphate spacer non-locking plate to prevent the loss of correction in the middle term.
authors: Centre for Sports and Exercise Medicine, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Mile End Hospital, 275 Bancroft Road, London, E1 4DG, UK. n.maffulli@qmul.ac.uk
authors: Nicola
authors: N
authors: Maffulli
authors: Mattia
authors: M
authors: Loppini
authors: Umile Giuseppe
authors: UG
authors: Longo
authors: Vincenzo
authors: V
authors: Denaro
authors: Francesco
authors: F
authors: Oliva
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001705:Bioprosthesis; D017760:Bone Malalignment; D001860:Bone Plates; D002130:Calcium Phosphates; D002417:Cattle; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery*; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods / Q000534:rehabilitation; D011183:Postoperative Complications; D011446:Prospective Studies; D011474:Prosthesis Design; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D002130:Calcium Phosphates; C018392:tricalcium phosphate