Evaluating inter- and intraobserver reliability in radiographic determination of wrist alignment following scaphoid excision and four-corner arthrodesis

Background: Four-corner arthrodesis is commonly performed for advanced collapse patterns of wrist arthritis. Reduction of the capitolunate (CL) angle during four-corner fusion is crucial to allow for the greatest radiocarpal joint arc of motion. Previous studies demonstrate variable inter- and intraobserver reliability of measuring the CL angle. However, in a four-corner fusion, hardware implementation and scaphoid excision can complicate carpal alignment measurements. The purpose of this study is to investigate inter- and intraobserver reliability of measuring carpal alignment parameters following scaphoid excision and four-corner arthrodesis. Methods: Three fellowship-trained orthopaedic hand surgeons evaluated 30 posteroanterior and lateral radiographs of wrists after scaphoid excision and four-corner fusion. Radiographic evaluation included analysis of the radiolunate angle (RL), CL angle, lunate posture, carpal height, carpal height ratio, hardware impingement, and arthrodesis technique. Intraclass correlation coefficients (ICCs) and kappa values were used to evaluate reliability of radiographic measurements. Results: RL and CL angles demonstrated very good inter- (ICCs: 0.657 and 0.693, respectively) and intraobserver agreement (ICCs: 0.576 to 0.924 and 0.596 to 0.811, respectively). Hardware impingement metrics by dorsal prominence and radiocarpal prominence had excellent interobserver reliability of 0.821 and 0.803, respectively. ICC values for arthrodesis technique were equal to 1.00. The inter- and intraobserver ICC values for the number of screws/staples used were in excellent agreement ranging from 0.910 to 1.000. Conclusions: Our study demonstrated favorable intra- and interobserver reliability at assessing carpal alignment following scaphoid excision and four-corner arthrodesis and these metrics potentially could be used in future research to evaluate long-term surgical outcomes.