Foot and Ankle Trauma Flashcards
Examples of foot and ankle trauma
-Ankle fractures
-5th metatarsal fracture
General principles of foot and ankle injury
-Correct F&A biomechanics are very important, since the whole bodyweight passes through a small surface area with each step (~9.5cm2).
=For reference, the ~S.A. of the adult knee is 120cm2
-Therefore, even small anatomical changes can lead to profound consequences, which emerge rapidly.
-Furthermore, due to the anatomical complexity, pathology in one area typically results in further pathological changes elsewhere in the foot and ankle
What anatomical parts may ankle fractures involve?
-Lateral malleolus
-Medial malleolus
-Posterior malleolus
-There is also ligamentous injury, which is not appreciated on the XR:
=Deltoid ligament (medially)
=Lateral ligament complex
=Distal tibiofibular syndesmosis and interosseous membrane
-Typically due to torsion (but also abduction /adduction)
What is stability determined by?
-Talar shift: if the talus has displaced, the fracture is unstable
-Weber classification.
=A – Stable (distal to syndesmosis connecting tibia to fibula)
=B – Potentially stable (at level of syndesmosis)
=C - Unstable (above level)
-Management determined by the predicted stability of the fracture
Describe Talar shift on XR
-On a Mortise X-ray view (foot in 15degof internal rotation)
=All spaces should be equal in depth
=This can be very subtle, but any degree of displacement indicates instability, so the radiograph should be carefully scrutinised
-Dime sign (red circle): Indicates correct fibular length
Describe a Maisonneuve fracture
-A Weber C variant
=Proximal fibula #
=Disruption of the deltoid ligament medially
-Unstable
-Anyone with a proximal fibula # -> you must examine the medial ankle for tenderness
Management of ankle fractures
-Stable
=Moonboot + FWB (fully weight bear)
=XR in 6/52
-Potentially stable
=Moonboot + FWB
=XR in 1/52
-Unstable
=ORIF (open reduction internal fixation)
Ottawa ankle rules?
Describe ankle sprains
-Stretching of the ankle ligaments. This may result in:
=Inflammation -> swelling +++
=Rupture of the vessels within the ligaments -> bleeding (ecchymosis)
+/- Tearing of the ligaments -> laxity -> abnormal joint position
==Instability
==Chondral injury
-Typically due to inversion of the ankle
-In the ankle, this can be divided into high ankle sprains involving the syndesmosis and low ankle sprains involving the lateral collateral ligaments
Presentation of ankle sprains
-Pain, tenderness
-Swelling
-Bruising
+/- instability
Usually able to weight bear unless severe
-Swelling and ecchymosis
-Exquisite tenderness over the affected ligaments (usually ATFL or CFL)
-Complete, but painful to move
-Inversion injury most common mechanism
Investigation of ankle sprain
-Radiographs should be done according to the Ottawa ankle rules as 15% of sprains are associated with a fracture.
-MRI if persistent pain and useful for evaluating perineal tendons.
-Ottawa ankle rules
=Ankle X ray if pain in malleolar zone and bone tenderness at posterior edge or tip of lateral malleolus/ medial/ inability to bear weight both immediately and in emergency department
=Foot X ray if pain in midfoot zone and bone tenderness at base of 5th metatarsal/ navicular/ inability to bear weight both immediately and in emergency department
-MRI if symptoms do not settle after 6-8/52
=?Osteochondral injury ?Peroneal tendon injury
Management of ankle sprain
-Acute:
=Rest, ice, compression, elevation (RICE) in almost all
==Very severe injuries may need casting and NWB for ~10/7
-Occasionally a removable orthosis, cast and/or crutches may be required for short-term symptom relief.
If symptoms fail to settle or there is significant joint instability then an MRI and surgical intervention may be contemplated, but this is rare.
=Early mobilisation and PT is beneficial
-If ongoing instability:
=Modified Brostrom repair
Overview of 5th metatarsal fractures
-Most common
-Proximal avulsion fractures (pseudo-Jones fractures): most common type. Occurs at the proximal tuberosity. Usually associated with a lateral ankle sprain and often follow inversion injuries of the ankle.
-Jones fractures: much less common. This is a transverse fracture at the metaphyseal-diaphyseal junction.
-Features;
=Pain and bony tenderness
=Swelling
=Antalgic gait
-Investigations
=X-rays: distinguishes between displaced and non-displaced fractures. This differentiation guides subsequent management options. Although stress fractures may appear normal on X-ray, sometimes there is a periosteal reaction seen on 2-3 weeks later.
=Isotope scan or MRI: in the case of stress fractures, X-rays are often normal and may remain normal in up to half of all cases. An isotope bone scan or MRI may help to establish the presence of a stress fracture.
Ottawa Rules for ankle x-rays
-An ankle x-ray is required only if there is any pain in the malleolar zone and any one of the following findings:
=bony tenderness at the lateral malleolar zone (from the tip of the lateral malleolus to include the lower 6 cm of posterior border of the fibular)
=bony tenderness at the medial malleolar zone (from the tip of the medial malleolus to the lower 6 cm of the posterior border of the tibia)
=inability to walk four weight bearing steps immediately after the injury and in the emergency department
Achilles tendon rupture overview
-Audible pop in ankle whilst playing sport or running/ sudden onset significant pain in calf or ankle/ inability to walk or continue sport
-Simmond’s triad, to help exclude Achilles tendon rupture. This can be performed by asking the patient to lie prone with their feet over the edge of the bed. The examiner should look for an abnormal angle of declination; Achilles tendon rupture may lead to greater dorsiflexion of the injured foot compared to the uninjured limb. They should also feel for a gap in the tendon and gently squeeze the calf muscles if there is an acute rupture of the Achilles tendon the injured foot will stay in the neutral position when the calf is squeezed.
-Ultrasound is the initial imaging modality of choice for suspected Achilles tendon rupture
-An acute referral should be made to an orthopaedic specialist following a suspected rupture.
Classification of ankle sprains
-Grade 1 (mild)
=Stretch or micro tear
=Minimal swelling
=Normal weight bear
-2 (mod)
=Partial tear
=Moderate swelling
=Minimal pain on weight bear
-3(severe)
=Complete tear
=Severe swelling
=Severe pain on WB
