Weight-bearing Radiographs to Evaluate Stability in Ankles With Isolated Weber Type B Fractures.

It is widely accepted that fractures in stable ankles can be treated non-operatively and fractures in unstable ankles needs internal fixation surgery (Michelson, Magid \& McHale, 2007, Gougoulias, Khanna, Seellariou, Maffulli, 2010). Clinical decision-making is thus based on ankle stability evaluation. The integrity of medial structures, mainly the deep deltoid ligament, is considered the most important determinant for stability of the ankle mortise (Michelson, Magid \& McHale, 2007, Gougoulias, Khanna, Seellariou, Maffulli, 2010). Weber B fractures, with no obvious sign of medial side injury on initial plain radiographs, have to be considered of uncertain stability until adequate stress testing is performed.

Currently there is no definite consensus on what test(s) best determines stability in ankles with undisplaced, isolated lateral malleolar fractures. Much used methods comprises manual stress radiographs and gravity stress radiographs (McConnel, Creevy \& Tornetta, 2004). However recent studies have shown that such methods overestimate the need for surgical fixation indicating the need for a different method to make up the basis for surgical indication (Dawe, Shafafy, Quayle, Gougoulias, Wee \& Sakellariou, 2015, Hastie, Akhtar, Butt, Baumann \& Barrie, 2015, Holmes, Acker, Murphy, McKinney, Kadakia \& Irwin, 2016, Hoshino, Nomoto, Norheim \& Harris, 2012, Koval, Egol, Cheung, Goodwin \& Spratt (2007), Seidel et al., 2017, Weber, Burmeister, Flueckiger \& Krause, 2010). Authors of recent studies have proposed weightbearing radiographs as an alternative method to distinguish stable and unstable fractures, significantly reducing the need for operative treatment (Dawe et al., 2015, Hastie et al., 2015, Hoshino et al, 2012, Holmes et al., 2016, Seidel et al., 2017, Weber et al. 2010).

To evaluate weight-bearing radiographs ability to determine stability our primary focus is to evaluate if conservative treatment for "gravity unstable/weightbearing stable" ankles produces different outcomes than conservative treatment for "gravity stable/weightbearing stable" ankles.

Participants will be assigned to non-operative or surgical treatment based on ankle stability evaluation using results from weightbearing radiographs consistently. Stable ankles will be treated non-operatively with a functional brace (AirCast) for 6 weeks. Participants will be instructed to bear weight as tolerated and to actively do standardized range-of-motion exercises. Standard operative treatment is open reduction and internal fixation of the fracture using plate and screws.

Ankles that are considered stable using weight-bearing radiographs AND gravity stress test will be assigned to conservative treatment

Other: Conservative treatment

Ankles that are considered stable using weight-bearing radiographs but unstable using gravity stress test will be assigned to conservative treatment

Other: Conservative treatment

Ankles that are considered unstable using weight-bearing radiographs AND gravity stress test will be assigned to open reduction internal fixation (ORIF)

Procedure: Open reduction internal fixation (ORIF)

Ankles that are considered unstable using weight-bearing radiographs but stable using gravity stress test will be assigned to open reduction internal fixation (ORIF)

Procedure: Open reduction internal fixation (ORIF)

Open fracture reduction followed by internal fixation using a plate and screws. The goal is an osteosynthesis that allow for early range-of-motion exercises, but weightbearing is usually not tolerated until 6 weeks postoperatively.

Conservative treatment involves ankle protection with a functional brace (AirCast) for 6 weeks. Participants will be instructed to bear weight as tolerated and to actively do standardized range-of-motion exercises.

Time frame: 10 years

Ankle/foot specific patient-reported outcome measure

Time frame: 10 years

Ankle/foot specific patient-reported outcome measure. Maximum score (100) = best. Minimum score = 0 (worst). Poor = 0-30, Fair = 31-60, Good = 61-90, Excellent = 91-100. Presented as total score (0-100).

Time frame: 24 months

Ankle/foot specific patient-reported outcome measure

Time frame: 24 months

Visual analogue pain scale - patient reported. Scale 0-10. 10 = worst possible pain, 0 = no pain

Time frame: 24 months

Genereic health related quality of life patient reported outcome measure

Time frame: 10 years

Radiographic result

Time frame: 24 months

Yes/No for malalignment, deep vein trobosis, nerve injury, wound infection, delayed wound healing and crossover to surgery (including reason for crossover).

Time frame: 24 months

Measured in degrees with a goniometer ad modum Lindsjö.

Time frame: 24 months

Calf circumference in centimeters measured 10 cm distal to the tibial tubercle Calf circumference in centimeters measured 10 cm distal to the tibial tubercle using measuring tape

Weight-bearing Radiographs to Evaluate Stability in Ankles With Isolated Trans-syndesmotic Lateral Malleolar (Weber Type B) Fractures.