SLR - September 2020 - Chase M. Tamashiro

Better Outcome for Suture Button Compared with Single Syndesmotic Screw for Syndesmosis Injury: Five-Year Results of A Randomized Controlled Trial

Reference: Raeder BW, Figved W, Madsen JE, Frihagen F, Jacobsen SB, Andersen MR. Better Outcome for Suture Button Compared with Single Syndesmotic Screw for Syndesmosis Injury: Five-Year Results of A Randomized Controlled Trial. Bone Joint J. 2020 Feb;102-B(2):212-219

Scientific Literature Review

Reviewed By: Chase M. Tamashiro, DPM
Residency Program: Hoboken University Medical Center – Hoboken, NJ

Podiatric Relevance: Syndesmotic instability is a common occurrence that needs to be addressed with ankle fractures. Ends stage osteoarthritis has been reported in 78 percent of cases following ankle trauma. Traditionally, syndesmotic stabilization has been achieved using syndesmotic screws, but recent studies have shown favorable outcomes while using suture buttons for syndesmotic stabilization. The aim of this study was to compare clinical and radiological outcomes of suture button vs. syndesmotic screws five years after surgery.

Methods: This study was performed at two hospitals as a RCT with five-year follow-up from January 2011 to March 2013. Patients aged 18-70 years old who suffered an acute syndesmotic injury, with or without an OTA/AO type 44 C ankle fracture were included in this study. Exclusion criteria included open fractures, polytrauma, prior ankle injury, neurological impairment, and inability to consent. 97 patients were randomly assigned to either suture button of syndesmotic screw fixation (48 suture button, 49 syndesmotic screw). Syndesmotic screw fixation was achieved with a fully-threaded, self-tapping 4.5 millimeter quadricortical screw. Syndesmotic fixation was performed by 39 different surgeons and fixation was placed 2-4 centimeters proximal to the ankle joint. Outcome measures included evaluation at six weeks, six months, one year, two years, and  years follow-up, assessed using AOFAS, OMS score, EQ-5D index, VAS, and ankle range-of-motion compared to un-injured limb. CT scans of both ankles were performed post-operatively at two weeks, one year, two years and five years. This allowed for assessment of osteoarthritis according to Kellgren-Lawrence, and tib-fib distance of axial CT scans.

Results: Five-year follow-up results in 81 patients were obtained, with CT scan follow-ups in 77 of those patients. At five years, suture button showed significantly higher AOFAS and OMA scores compared to syndesmotic screw fixation. No difference in VAS, EQ-5D VAS, or EQ-5D index were found at 5 years. Ankle dorsiflexion was better in suture button but not clinically relevant. Talar osteophytes were 3.4 times more common and there was a higher prevalence of radiological osteoarthritis in the syndesmotic screw group. The difference between mean anterior tib-fib distance of contralateral limbs was significantly less in suture button group. The malreduction rate after five years was similar between both groups.

Conclusions: Their results show that patients treated with suture button had a higher mean AOFAS, OMA scores, better dorsiflexion, and lower rate of OA compared to syndesmotic screw group. Limitations include imbalance of fracture patterns due to randomization, where the suture button group had more medial and posterior malleolar fractures. Also, the follow-up exams were non-blinded. Strengths include the bilateral serial CT post-operative scans with a long follow-up period of five years. The suture button behaves like a dynamic implant, allowing the fibula to self-adjust in the incisura, making the implant more forgiving to perioperative malreduction. These long-term results favor the use of suture button for acute syndesmotic injuries.

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