title: Finite element analysis, mechanical assessment and material comparison of two volar slab constructs.
abstract: BACKGROUND
  In order to help prevent joint stiffness, the injured or postoperative hand is splinted in the intrinsic-plus position. We aimed to determine the strongest type of volar slab construct that would be appropriate in this treatment.
  
  
  METHODS
  Two constructs were compared, a double-ridged and a non-ridged slab. Two materials were used, plaster of Paris (POP) and resin. We performed finite element analysis (FEA) and mechanical assessment to establish which combination of construct and material resulted in the strongest volar slab. We were unable to form ridges on the resin slab, and therefore this construct was not tested.
  
  
  RESULTS
  Finite element analysis showed that most stress occurred at the wrist region, where all the slabs failed. The double-ridged POP slab was found to be 5.3 times stronger than the non-ridged POP slab and 1.4 times stronger than the non-ridged resin slab (p<0.001).
  
  
  CONCLUSIONS
  To improve strength of the conventional POP volar slab, we suggest forming two anterior ridges in the plaster.
authors.affiliation: Department of Orthopaedic Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB25 2ZN, UK. steven.w.hamilton@googlemail.com
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hamilton
authors.forename: Hussain
authors.initials: H
authors.lastname: Aboud
mesh_terms: D002370:Casts, Surgical; D004868:Equipment Failure; D020342:Finite Element Analysis; D006225:Hand / Q000601:surgery*; D006230:Hand Injuries / Q000601:surgery*; D006801:Humans; D008422:Materials Testing / Q000379:methods; D011182:Postoperative Care / Q000295:instrumentation; D013314:Stress, Mechanical