CAN CARPAL MALALIGNMENT PREDICT EARLY AND LATE INSTABILITY IN NONOPERATIVELY MANAGED FRACTURES OF DISTAL RADIUS?

Abstract

Various studies report a correlation between the severity of the primary displacement, carpal malalignment & an expectant loss of reduction over a given time period when treating distal radius fractures with cast immobilization. Recently, studies have attempted to classify carpal malalignments associated with displaced distal radial fractures based on Effective radio-lunate flexion (ERLF) into: midcarpal with ERLF < 250 and radiocarpal malalignment with ERLF > 250. The aim of this study was to assess the frequency of carpal instability as a concomitant lesion to fractures of the distal radius, delineate further various factors including associated carpal malalignment based on ERLF that are predictive of instability based on a timeline of early (one week) and late failure (six weeks) in an attempt to predict the final radiological outcome accurately

Radiographic alignment parameters were compared before and after reduction using paired t-tests and then also analysed in a multiple logistic regression analysis.

Early failure group: Regression analysis showed high correlation between the severity of axial shortening before reduction and at one week. Age, gender, presence of dorsal comminution, ulnar styloid fracture, initial dorsal angulation and flattening of radial angle were unreliable in predicting early failure at one week. Late failure group: We found radial shortening, dorsal tilt, presence of dorsal comminution & ERLF > 25 to be significant predictors of adverse radiological outcome at six weeks. Age, Gender, flattening of radial angle, ulnar styloid fracture as factors for secondary displacement when analyzed independently or in combination were not found to be significant predictors of late failure. The incidence of failure was significantly correlated to radiocarpal malalignment pattern in post reduction radiographs (ERLF> 25) and both at one and six weeks when analysed independently or in combination (p< 0.01)

Our study reaffirms the need to attention to initial fracture characteristics and highlights the importance of radiocarpal instability pattern on post reduction radiographs as a predictor of late instability. This would allow the surgeon to inform the patient of chance of success with closed treatment and alternative treatment options.