title: Outcomes of Bone Grafting of Bone Cysts After Total Ankle Arthroplasty.
abstract: BACKGROUND
  The operative treatment of bone cysts after total ankle replacements (TAR) is not well described. Bone cysts may cause component migration, implant failure, and pain. Surgery is performed on cysts with the goals of reducing pain and preventing component failure.
  
  
  METHODS
  We retrospectively evaluated a consecutive series of 726 primary TARs performed between January 1998 and May 2013 and identified those who had a subsequent bone cyst grafting procedure. We identified cyst location and method of treatment. Clinical outcomes including secondary procedures, infection rate, complications, and failure rate were recorded. Thirty-one patients were treated with a total of 33 operative procedures for bone cysts after TAR. Of these patients, 22 (71.0%) were males with an average age of 62.2 and median follow-up 65.9 months.
  
  
  RESULTS
  Intraoperatively, 22 tibial cysts (71.0%), 20 talar cysts (64.5%), 5 fibular cysts (16.1%), and 13 multiple cysts (41.9%) were treated. Allograft was used in 25 procedures (75.8%), calcium phosphate in 4 (12.1%), cement in 3 (9.1%), and autograft in 1 (3.0%). These procedures were supplemented by calcaneus autograft, allograft mixed with mesenchymal stem cells, platelet-rich plasma, recombinant human bone morphogenic protein-2, and demineralized bone matrix. There were no infections or wound complications. Of the 27 subjects with a successful second surgery, the success rate for bone grafting of cysts was 90.9% (95% CI: 50.8, 98.7%) at 24 months and 60.6% (95% CI: 25.1%, 83.4%) at 48 months. One patient needed a repeat bone grafting. The 4 failures observed postprocedure resulted in 3 tibial and talar component revisions, and 1 tibiotalocalcaneal (TTC) fusion.
  
  
  CONCLUSIONS
  Grafting bone cysts without revision of TAR was in general an effective and safe means for treating patients with peri-prosthetic bone cysts. Treatment with grafting and supplemental materials may improve implant survivorship and might improve the structural support surrounding the implant. Further exploration of the etiology of bone cysts may aid in the prevention and treatment of cystic formation in the TAR.
  
  
  METHODS
  Level IV, case series.
authors.affiliation: Medical University of South Carolina, Charleston, SC, USA cgross144@gmail.com.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Gross
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Jeannie
authors.initials: J
authors.lastname: Huh
authors.affiliation: Department of Biostatistics, Duke University, Durham, NC, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Green
authors.affiliation: Department of Radiology, Musculoskeletal Radiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Samit
authors.initials: S
authors.lastname: Shah
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: James K
authors.initials: JK
authors.lastname: DeOrio
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Easley
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Nunley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D064591:Allografts; D058737:Arthroplasty, Replacement, Ankle; D064592:Autografts; D001843:Bone Cements / Q000627:therapeutic use; D001845:Bone Cysts / Q000601:surgery*; D001857:Bone Matrix / Q000637:transplantation; D055396:Bone Morphogenetic Protein 2 / Q000627:therapeutic use; D002111:Calcaneus / Q000637:transplantation; D002130:Calcium Phosphates; D005260:Female; D006801:Humans; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D008875:Middle Aged; D053657:Platelet-Rich Plasma; D012189:Retrospective Studies
chemical_list: D001843:Bone Cements; D055396:Bone Morphogenetic Protein 2; D002130:Calcium Phosphates; C020243:calcium phosphate
keywords: bone cyst; osteolysis; total ankle arthroplasty