How Is Scaphoid Malunion Defined: A Systematic Review.

Background: Abnormal scaphoid alignment after fracture is used as an indication for fixation. Acceptable alignment after reduction and fixation of scaphoid fractures is not well defined. We systematically reviewed the literature to identify how scaphoid malunion is currently defined and by what parameters.

Methods: A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Multiple databases were searched for studies published in the English language that reported on outcomes after scaphoid malunion and included measurements to define malunions. Radiographic scaphoid measurement parameters were collected. Clinical outcome measures recorded included grip strength, wrist range of motion, and patient-reported outcome measures. Study quality was analyzed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Descriptive summaries of the studies are presented.

Results: The initial search yielded 1600 articles. Ten articles (161 participants, 93% males, mean age = 28.3 + 6.3 years, mean MINORS score = 10.2 + 1.6) were included and analyzed. Scaphoid malunion was defined if the lateral intrascaphoid angle (LISA) was >45° (3 articles), LISA >35° (1 article), and height to length ratio >0.6 (3 articles). Four out of 5 studies found no significant associations between patient outcomes and degree of scaphoid malunion measured on imaging.

Conclusions: There is a lack of consensus for defining scaphoid malunion on imaging and absence of correlation between findings on imaging and patient outcomes. Future studies defining scaphoid malunion should be appropriately powered, incorporate measures of intrarater and interrater reliabilities for all reported imaging measurements, and utilize validated patient-reported outcome measures to reflect that malunion is associated with inferior outcomes meaningful to patients.