Articular Congruity Is Associated with Short-Term Clinical Outcomes of Operatively Treated SER IV Ankle Fractures

SLR - August 2014 - An Nguyen

Reference: Berkes MB, Little MT, Lazaro LE, Pardee NC, Schottel PC, Helfet DL, Lorich DG.  J Bone Joint Surg Am. 2013 Oct 02;95(19):1769-1775. 

Scientific Literature Review

Reviewed By: An Nguyen, DPM
Residency Program: Hoboken University Medical Center

Podiatric Relevance: There are several specific studies that have supported the idea that an incongruent ankle joint after open reduction internal fixation is a strong indicator of poor clinical outcomes. This therapeutic level IV study aims to specifically focus on SER IV ankle fractures to substantiate previous studies that either an articular step-off, loose bodies within the ankle joint, and/or a gap in the articular surface will increase the patient’s likelihood of an unsatisfactory outcome.

Methods: This prospective study consisted of 108 patients who were treated from 2004 to 2010 by the same surgeon. Inclusion criteria consisted of an SER IV or SER IV-equivalent fracture which was evaluated utilizing computed tomography (CT), radiographs, and magnetic resonance imaging (MRI) which confirmed injury to posterior inferior tibiofibular and the deltoid ligament. In addition, patients had to have a clinical follow-up of more than one year and postoperative CT scans of the operatively treated ankle. The procedure was performed in the same manner for all patients, which included fixating the posterior malleolus regardless of the fragment size. A posterior splint was worn for two weeks and then progressive weight bearing with CAM walker to allow for early range of motion following a total of six weeks of non weight-bearing. Patients were evaluated as to whether they had a congruent or incongruent ankle joint if they met any of the following criteria: an articular step-off of >2mm, loose bodies in the joint, and a joint surface gap of >2mm from a day one post-operative CT scan image. The primary outcome measure was validated by using the Foot and Ankle Outcome Score (FAOS)

Results: A total of 108 patients (73 female, 35 male) with an average age of 51 years had an average follow-up of twenty-one months. Seventy-two patients (67 percent) had a congruent ankle joint and thirty-six (33 percent) met at least one of the criteria for articular incongruity. The results of the FAOS revealed that the group with an incongruent ankle joint had worse clinical outcomes in regard to symptoms, pain, and activities of daily living.  However, the percentages of patients with normal ankle range of motion were the same in both groups. 

Conclusions: This study concludes that of the 108 patients that were operated on for an SER IV ankle or SER IV-equivalent fracture, those with an incongruent joint based on CT imaging had poor clinical outcomes, which were supported with statistical analysis and clinical evaluation with a minimum of one year follow-up. Long-term studies may need to be performed to determine if articular incongruency may lead to ankle arthritis.