Radiographic Criteria for Undergoing an Ulnar Shortening Osteotomy in Madelung Deformity: A Long-term Experience From a Single Institution.

BACKGROUND There are no established guidelines on the age or the severity of deformity for which an ulna shortening osteotomy or ulna epiphysiodesis should be performed in children and adolescents with Madelung deformity. The purpose of this study was to identify radiographic criteria associated with the eventual performance for an ulna shortening procedure in this patient population. METHODS We retrospectively identified 41 wrists in 31 Madelung patients (mean±SD age 13.8±3.2 y) subjected to surgical correction of their deformity between 1999 and 2013. We assessed established radiographic criteria (ulnar tilt, lunate subsidence, palmar carpal displacement, ulnar variance) at preoperative and postoperative visits. Univariate and multivariate analyses were carried out to determine which radiographic criteria were associated with the performance of an "ulnar shortening procedure" at the first (index) surgical procedure. RESULTS Eleven wrists were subjected to an ulna shortening osteotomy at the index and 5 at subsequent procedures; 10 cases received an ulnar epiphysiodesis (mean age 13.4±1.5 y). Ulnar shortening at the index procedure was associated with significantly higher preoperative lunate subsidence, ulnar variance, and palmar carpal displacement. Ulnar variance of >5 mm and lunate subsidence >4 mm resulted in a respective 67% and a 53% likelihood of undergoing ulnar shortening osteotomy; palmar carpal displacement over 22 mm resulted in a 50% likelihood for ulnar shortening. Patients who required a subsequent procedure (n=8) showed a significant increase in palmar displacement between surgeries. None of the 10 cases with a primary ulnar epiphysiodesis received a subsequent ulnar shortening; none of those undergoing late ulnar shortenings had an ulna epiphysiodesis at their index procedure (at 10.3±4.3 y). CONCLUSIONS Lunate subsidence, ulnar variance, and palmar carpal displacement were significant radiographic criteria for undergoing an ulnar shortening osteotomy at our institution. A shortening osteotomy may be prevented by early ulna epiphysiodesis in skeletally immature children older than 10 years of age. LEVEL OF EVIDENCE Therapeutic level IV-case series.