Association Between Lunate Morphology And Carpal Instability Patterns And Scaphoid Fracture Location In Scaphoid Nonunions And Treatment

Purpose:Dorsal intercalated segment instability(DISI) is the most common type of the carpal instability in scaphoid nonunions.DISI is determined by the pose of lunate to the distal of the radal.Type I lunates have a single distal facet for articulation with the capitate; typeⅡlunates have an additional (medial) hamate facet on the distal articular surface. We retrospectively reviewed a series of patients with scaphoid nonunions to determine if there was an assoc-iation between lunate morphology and the degree of carpal instability observed. Association between lunate morphology and the location of the scaphoid fracture (proximal or waist) was also investigated.At the same time,we also have reviewed the treatment of these patients,to evaluate the result of different bone graft of scaphoid nonunion associated with or not DISI, investigate the efficient treatment methods of scaphoid nonunion associated with or not DISI.Methods:We collected patients with established scaphoid nonunions and operated in Tianjin Hospital from March,2007 to January.2010 acoreding to study needing.To get their standard postanterier and lateral radiographs from Tianjin Hospital Rdiograph Interact Plat.there were 30 men,24 right wrist,6 left wrist,a mean age of 27 years.1 patient was 23 years old woman,her right wrist was involved. Were evaluated for Lunate morphology according to Viegas and Burgess,scaphoid fracture location according to Russe, and radiolunate angle were determined. Statistical analysis was applied chi square test,there was statistical significance if P<0.05.To those who did not associated DISI and humpback deformation treated by Russe bone grafting and Kirschner wire or Bolt screw fixation,to those who associated DISI and humpback deformation treated by wedge bone grafting and Kirschner wire or Bolt screw fixation.palmar approach was applied for middle 1/3 fracture,proximal pole facture was applied dorsal approach.Once the sutures have been removed,applied short arm orthoplast splint to protect the repair till to healing.Remveal of the splint and active mobiliz-ing exercises are encouraged.Rexaming per a month,capered with uninjured side and recored the follow-up results.To evaluate the wrist function by Coony Score. Results:TypeⅠlunates were present in 22 patients(70.9% of all). Of these,15 were found to have a dorsal intercalated segment instability pattern (radiolunate angle greater than 15 degrees).By contrast, only 2 of the patients with typeⅡlunates exhibited this pattern of instability.χ2 Test is applied,χ2=8.358,P<0.05,which has statistically significant.3 patients had type I lunates with a fracture line in the middle one third,one patient had type II lunates with a fracture line in the proximal one third. No significant association was found b--etween lunate morphology and the scaphoid fracture location.12 of patients sca-phoid nonunion with Type I were applied Russe bone grafting,10 of patients were applied wedge bone grafting.7 of patients with typeⅡlunates were applied Russe bone grafting,2 of patients were applied wedge bone grafting. Of these,15 patients fixed by 1 or 2 Kirschner wire,16 patients fixed by Bolt screw.Only 1 patient with proximal pole facture failed,others successfully healed.The healing rate reached 96.8%.Average healing period is 17.6 weeks after operati-on.Average healing period of patient fixed by Kirschner wire are 19.3 weeks,fixed by Bolt scew are 16.1 weeks.Evaluated by Coony Score, We obtained exc-ellent results in 20 patients,good results in 7.Of 17 patients with DISI,deformation have been corrected except 1.Conclusions:TypeⅡlunate morphology is associated with significantly de-creased incidence of dorsal intercalated segment instability (DISI) deformity in cases of established scaphoid nonunion (p<0.05).Lunate morphology, however, was not significantly associated with the location of the scaphoid fracture in t-hese cases (p >0.1).Russe technique is an effective and safe method of treatment for scaphoid nonunion;The result of wedge bone graft and inernal fixing is satisfied for these are associated with DISI but no proximal pole ischemia nerosis.