Articular congruity is associated with short-term clinical outcomes of operatively treated SER IV ankle fractures.

BACKGROUND:
With regard to supination-external rotation type-IV (SER IV) ankle fractures, there is no consensus regarding which patient, injury, and treatment variables most strongly influence clinical outcome. The purpose of this investigation was to examine the impact of articular surface congruity on the functional outcomes of operatively treatment of SER IV ankle fractures.

METHODS:
A prospectively generated database consisting of operatively treated SER IV ankle fractures was reviewed. Postoperative computed tomography (CT) scans were used to assess ankle joint congruity. Ankles were considered incongruent in the presence of >2 mm of articular step-off, intra-articular loose bodies, or an articular surface gap of >2 mm (despite an otherwise anatomic reduction) due to joint impaction and comminution. Patients with at least one year of clinical follow-up were eligible for analysis. The primary and secondary outcome measures were the Foot and Ankle Outcome Score (FAOS) and ankle motion.

RESULTS:
One hundred and eight SER IV fractures met our inclusion criteria. The average duration of follow-up was twenty-one months. Seventy-two patients (67%) had a congruent ankle joint, and thirty-six (33%) had elements of articular surface incongruity on postoperative CT scanning. These two groups were similar with regard to comorbidities and injury and treatment variables. At the time of the final follow-up, the group with articular incongruity had a significantly worse FAOS with regard to symptoms (p = 0.012), pain (p = 0.004), and activities of daily living (p = 0.038). Those with articular incongruity had worse average scores in the FAOS sport domain as well. No significant differences in ankle motion were found between the two groups.

CONCLUSIONS:
In this population of patients with an operatively treated SER IV ankle fracture, the presence of postoperative articular incongruity correlated with inferior early clinical outcomes. Orthopaedic surgeons should scrutinize ankle fracture reductions and strive for perfection to allow for the best possible clinical outcome.

LEVEL OF EVIDENCE:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.