The Radiographic Union Score for Hip (RUSH) Identifies Radiographic Nonunion of XXXX .

@entity1 @entity2249 @entity174
BACKGROUND: The Radiographic Union Score for Hip (RUSH) is a previously validated outcome instrument designed to improve intra- and interobserver reliability when describing the radiographic healing of @entity2249 . The ability to identify @entity174 that have not healed is important for defining nonunion in clinical trials and predicting @entity1 who will likely require additional surgery to promote @entity174 healing. We sought to investigate the utility of the RUSH score to define @entity2249 nonunion. QUESTIONS/PURPOSES: (1) What RUSH score threshold yields at least 98% specificity to diagnose nonunion at 6 months postinjury? (2) Using the threshold identified, are @entity1 below this threshold at greater risk of reoperation for nonunion and for other indications? METHODS: A representative sample of 250 out of a cohort of 725 @entity1 with adequate 6-month hip radiographs was analyzed from a multinational elderly hip @entity174 trial (FAITH). All @entity1 had a @entity2249 and were treated with either multiple cancellous screws or a sliding hip screw. Two reviewers independently determined the RUSH score based on the 6-month postinjury radiographs and interrater reliability was assessed with the interclass correlation coefficient (ICC). There was substantial reliability between the reviewers assigning the RUSH scores (ICC, 0.81; 95% confidence interval [CI], 0.76-0.85). The RUSH score is a checklist-based system that quantifies four measures of healing: cortical bridging, cortical @entity174 disappearance, trabecular consolidation, and trabecular @entity174 disappearance.. @entity174 healing was determined by two independent methods: (1) concurrently by the treating surgeon using both clinical and radiographic assessments as per routine clinical care; and (2) retrospectively by a Central Adjudication Committee using complete obliteration of the @entity174 line on radiographs alone. Receiver operating characteristic tables were used to define a RUSH threshold score that was > 98% specific for @entity174 nonunion. RESULTS: A threshold score of < 18 was associated with a 100% specificity (95% CI, 97%-100%) and a positive predictive value of 100% (95% CI, 73%-100%) for radiographic nonunion. In contrast, using the @entity174 healing assessments of the treating surgeons failed to identify a useful discriminatory nonunion threshold and the highest positive predictive value was 43%. With respect to complications, @entity1 with RUSH scores below 18 had greater risk of undergoing reoperation for nonunion (reoperation when < 18: six of 13 [46%]; reoperation when >=  18: 11 of 237 [54%]; relative risk [RR], 9.9 [95% CI, 4.4-22.7]; p < 0.001) and for all indications (reoperation when < 18: eight of 13 [62%]; reoperation when >=  18: 54 of 237 [38%]; RR, 2.7 [95% CI, 1.7-4.4]; p = 0.004). CONCLUSIONS: The 6-month RUSH score is a reliable method for assessing radiographic healing. Our results highlight the discordance between radiographic determinations and clinician assessments of @entity174 healing and stress the need for clinical data to be incorporated in research studies evaluating @entity174 healing. LEVEL OF EVIDENCE: Level III, diagnostic study.
