Surgical Versus Conservative Treatment of Weber B1 Fracture: Functional Outcome Using Gait Analysis

The decision whether to operate an ankle fracture or not is often highly dependent on the surgeon's individual judgment. There is consensus that non-displaced Weber A-type fractures rarely require operative treatment, and that Weber C-type or grossly displaced fractures are unstable and therefore require surgery. The decision for appropriate treatment is less clear for minimally displaced Weber B-type ankle fractures, and especially Weber B1 fractures are treated either surgically or conservatively at our clinic.

Conservative management of ankle fractures generally comprises immobilisation in a below-knee VacoPed or cast for six weeks to stabilise the fracture and allow osseous and soft tissue healing. Surgical treatment involves the reduction (if displaced) of the fractured fragments and fixation using various devices such as metal plates, screws, or intramedullary rods. While patients show changes in plantar pressure distribution during gait 18 months after surgical treatment of ankle fractures, to date the functional outcome regarding ankle joint mechanics during daily activities are unknown. Understanding gait function is important because compromised function may not only limit a persons daily activities but also may lead to secondary conditions such as osteoarthritis at the ankle or at adjacent joints.

The primary objective is:

• To compare differences in hindfoot and forefoot kinematics between level and uphill treadmill walking in relation to passive range of motion

The secondary objectives are:

* To compare ankle biomechanics during overground walking and level and uphill treadmill walking between patients with Weber B1 fracture treated either surgically or conservatively and healthy control persons.
* To determine the relationship between passive ankle range of motion, lower leg muscle strength and dynamic ankle range of motion.
* To determine the relationship between lower leg muscle strength and balance.
* To determine the relationship between dynamic range of motion and the Foot and Ankle Outcome Score.

At the initial assessment, written informed consent will be obtained before participants will undergo a clinical exam (inspection and palpation of the foot, measurement of bilateral passive ankle range of motion). All participants will complete the Foot and Ankle Outcome score and the EQ-5D-5L health questionnaire to obtain pain and functional scores. Participants will be able to familiarize with treadmill walking at their preferred walking speed. Surface electrodes will be placed bilaterally over the tibialis anterior, gastrocnemius medialis and lateralis, soleus, and peroneus longus. Isokinetic muscle strength in ankle plantarflexion/ dorsiflexion will be tested using the Biodex system 4 Pro. Reflective surface markers will be placed bilaterally on anatomic landmarks according to the PlugIn Gait model9 and a specific foot model. These markers are seen by 8 Vicon cameras. Data for a standing reference trial will be collected, and participants will be asked to walk back and forth on a flat walkway until three valid left and right steps will be recorded (force plate hit centrally, approximately 10 minutes). Then, they will be asked to balance on one leg for 30 seconds per leg. Participants will be asked to stand on the treadmill (h/p cosmos, Zebris), and they will perform three single-limb heel rises with each leg while kinematic, electromyography (EMG), and pressure data will be measured. Participants will then walk barefoot for 2 minutes at 0% slope while kinematic, EMG, and pressure data will be recorded. Subsequently, the treadmill incline will be increased to 15%, and data for 2 minutes walking at this slope will be recorded.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years
* Surgical or conservative treatment after lateral malleolar fracture
* ≥12 months follow-up

Exclusion Criteria:

* Neuromuscular disorders affecting gait
* Additional pathologies that influence the mobility of the ankle joint
* Bilateral trauma at presentation
* Persistent use of walking aids
* Inability to provide informed consent