Non-operative Treatment of the Medial Malleolus in Bi- and Trimalleolar Ankle Fractures: A Randomized Controlled Trial

SLR - September 2013 - Amanda Quisno

Reference: Hoelsbrekken SE, Kaul-Jensen K, Morch T, Wikia H, Clemetsen T, Paulsrud O, Gunnar P, Stiris M, Stromsoe K.  Journal of Orthopedic Trauma, 2013 Feb 28 [Epub ahead of print]

Scientific Literature Review

Reviewed by: Amanda Quisno, DPM
Residency Program: Grant Medical Center

Podiatric Relevance: Ankle fractures are a very common traumatic injury treated by foot and ankle surgeons, with open reduction and internal fixation (ORIF) being indicated for the treatment of displaced and unstable fractures. The medial complex consisting of the medial malleolus and deltoid ligament is one of the structures which provides stability to the ankle joint, and was once thought to be the key to anatomical reduction and joint stability. This idea was later challenged with most surgeons now agreeing that anatomical alignment of the fibula and lateral structures is key to re-establishing ankle joint congruity, and that the medial malleolus tends to reduce with ORIF of the lateral component. Knowing this, the authors sought to establish whether or not it is necessary to treat medial malleolar fractures with ORIF if they are non-displaced following adequate ORIF of the lateral component.    

Methods: Patients with bi- or trimalleolar OTA/AO type 44 ankle fractures with displacement of the medial malleolus of less than two millimeters following ORIF of the lateral component were randomized to either internal fixation or non-operative treatment of the medial malleolus. There were a total of 37 patients in the fixation group and 45 patients in the no fixation group. Age, gender, body mass index (BMI), ASA classification, and co-morbidities were recorded prior to surgery. All patients followed the same postoperative protocol regardless of treatment. Outcome measures included the Olerud Molander Ankle score (OMA) and the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score. The same radiologist also examined postoperative radiographs for the presence of post-traumatic arthritis which was evaluated as Stage I-IV according to the criteria of Magnusson. A persistent radiolucent fracture line defined non-union. 

Results: There was a median follow-up of 39 months. BMI, ASA score and presence of diabetes were similar across treatment groups, although the group treated with ORIF had a higher percentage of obese patients and ASA score of III. The mean duration of surgery was significantly longer in the fixation group (102 minutes vs. 75 minutes), however the number of post-op infections was similar. There were no significant differences with respect to OMA or AOFAS or VAS scores or the development of osteoarthritis. Four patients treated non-operatively developed nonunion of the medial malleolus, although these patients reported no functional disabilities and actually had higher than average OMA and AOFAS scores.  

Conclusions: Non-operative treatment of non-displaced medial malleolar fractures leads to acceptable outcomes which are functionally comparable to ankle fractures treated with ORIF of both malleoli. A potential disadvantage is a higher rate of non-union of the medial malleolar fracture. Longer term follow-up studies are needed ascertain the progression of post-traumatic arthritis with non-operative treatment of the medial malleolus, and given this uncertainty the authors recommend reserving non-operative treatment only for those situations when the soft tissue envelope medially does not permit surgery.