SLR - June 2013 - Evie Plummer
Reference: Berkes MB, Little MTM, Lazaro LE, Sculco PK, Cymerman RM, Daigl M, Helfet DL, Lorich DG. Malleolar Fractures and Their Ligamentous Injury Equivalents Have Similar Outcomes in Supination-external Rotation Type IV Fractures of the Ankle Treated by Anatomical Internal Fixation. J Bone Joint Surg Br 2012;94-B:1567–72.Scientific Literature Review
Reviewed By: Evie Plummer, DPM
Residency Program: North Colorado Medical Center Podiatric Medicine and Surgical Residency
Podiatric Relevance: Ankle fractures are a common injury treated by many podiatric physicians, and it is important to assess injury pattern and outcome among these fractures. There has been previous speculation within the literature suggesting that the presence of a malleolar fracture may be associated with a worse outcome than a corresponding ligamentous injury. Previous studies, however, have included heterogeneous groups of injury. The purpose of this study was to determine whether any specific pattern of bony and/or ligamentous injury among a series of surgically treated supination-external rotation type IV (SER IV) ankle fractures was associated with a worse prognosis.
Methods: A prospective, cohort study was performed assessing 108 SER IV ankle fractures treated operatively by a single surgeon between 2004 and 2010. Pre-operative radiographs and MRIs were undertaken on each patient to precisely characterize the injury pattern, and operative treatment consisted of fixation of all malleolar fractures. Patients were placed into one of four groups based on injury pattern: trimalleolar fracture, posterior malleolar fracture combined with deltoid tear (PM + deltoid), torn PITFL with a medial malleolar fracture (PITFL + MM), or pure SER IV equivalents with torn PITFL and deltoid ligaments. Postoperative CT was used to assess reduction, and minimum follow up to meet inclusion criteria was one year. The primary and secondary outcome measures were the Foot and Ankle Outcome Score (FAOS) and the range of movement of the ankle.
Results: 108 of 176 SER IV ankle fractures met the inclusion and exclusion criteria with complete FAOS data. A total of 50 (46 percent) of the injuries were trimalleolar fractures, 19 (18%) involved the PM+deltoid, 16 (15 percent) involved the PITFL+MM, and the remaining 23 (21 percent) injuries were pure SER IV equivalents (PITFL+deltoid tear). There were noted to be differences regarding injury type, gender, and age distribution: The PITFL+MM group was more often associated with an open fracture, and the trimalleolar group had a significantly higher proportion of women along with older mean age, whereas the SER IV equivalent group consisted of younger patients. Otherwise, there were no statistically significant differences between the four groups in regard to demographics, comorbidities, injury data, and post-operative complications or reduction.
Conclusions: When comparing the described injury patterns associated with SER IV ankle fractures, no injury pattern was associated with a significantly worse outcome according to the FAOS, and there was no difference in the percentage of patients with a normal final range of movement. These outcomes defeat the hypothesis that malleolar fractures have a worse outcome than ligamentous injuries. Although previous studies have shown that injury patterns which include a posterior or medial malleolar fracture have a worse prognosis, these studies have involved large heterogenous groups of fractures of the ankle without confirming the specific pattern of injury. A strength of this current study involves the pre-operative use of MRI on each patient to ensure an appropriate anatomical diagnosis, thereby creating a homogenous cohort. Other factors inherent to the injury and treatment, however, may play a more important role in predicting outcome than simply characterizing the fracture pattern, and this statement requires further investigation.