Internal Fixation of Ankle Fractures 6-10 1

Objectives Review ankle anatomy Identify the indications & treatment goals for ORIF of ankle fractures Summarize the implant options

Anatomy Ankle Bones Formed by medial malleolus of tibia, and lateral malleolus (fibula) Talus sits in “mortise” (as in “mortise & tenon”) Fibula Tibia Talus

Anatomy Ankle Soft Tissues Ligaments connect ankle on medial & lateral sides Important for stability

Anatomy Ankle Soft Tissues Fibula connected to tibia by fibrous band of tissue called syndesmosis Also important for stability

Ankle Fractures 1

Ankle Fractures History Physical examination Twisting injury Immediate pain – lateral and/or medial Difficulty weight-bearing Physical examination Malleolar pain (posterior & anterior) Swelling Neurovascular involvement

Ankle Fractures Radiographs Ankle Series: AP, mortise, lateral “Rule out” other injuries: Osteochondral injuries Lateral process fracture Anterior calcaneus fracture Base of 5th MT fracture AP Mortise Lateral

Ankle Fractures Classification Weber / AO Classification based on level of fibula fracture A – Below syndesmosis B – At syndesmosis C – Above syndesmosis

Simple Classification: Stable & Unstable Stable fractures Most commonly involve medial or lateral side only Talus remains anatomic relative to tibia

Simple Classification: Stable & Unstable Unstable fractures Disruption of 2 or more aspects of the mortise -- bone and/or ligament Talus may sublux or be dislocated from tibia

Stable Examples

Unstable Examples

Indications for Surgery Ankle Fractures Inability to obtain or maintain an anatomic mortise (unstable fracture pattern) Open fractures

Basic Set-Up Ankle Fractures Supine position most common Occasionally prone for direct approach to posterior malleolus Bump beneath ipsilateral buttocks (allows easier approach to fibula) Tourniquet Prep / drape to above knee Pre-op antibiotics Fluoroscopy or X-ray

General Considerations Small size of ankle bones = dictates implant sizes Multiple complex 3-D articulations Weight bearing structure subject to high stresses (2 – 5x body weight)

General Considerations Limited soft tissue coverage

Instrumentation Ankle Fractures Small fragment set Cannulated screws K-wires Cerclage wire Power Have mini-frag available

Ankle Fracture Surgical Tx Type One malleolus Bimalleolar Tri-malleolar Treatment Fix fibula with screw / TB wire / plate Plate fibula, lag screw tibia (medial malleolus) Plate fibula, lag screw tibia, fix posterior if >20 - 25% articular surface involved

Implant Considerations Lateral Malleolus One-third tubular plate & 3.5 mm cortex screws Lateral Posterior 3.5mm compression plate for unstable fractures

Implant Considerations Lateral Malleolus Locking plates -- lateral or posterolateral Osteoporotic bone Unstable fractures Distal fractures

Implant Considerations Lateral Malleolus Hook Plate Used to obtain purchase in very distal fibula fractures

Implant Considerations Posterior Malleolus Posterior to anterior Anterior to posterior

Implant Considerations Medial Malleolus Two partially threaded 4.0 mm cancellous screws K-wires Cerclage wire for tension band technique

Syndesmosis Fixation Indications Syndesmotic instability after fixation of malleolus Consider if fibula fracture > 4 cm above joint line & Maisonneuve’s fracture Have bone hook on back table to check stability Have large frag screws & instruments available

Implant Considerations Syndesmosis Surgeons choice of large or small fragment fully threaded screws, one or two Not inserted as lag screw, but as a positioning screw (threads engage all cortices) Secures position of fibula next to tibia allowing torn syndesmotic tissues to heal May be removed in 6 - 12 weeks

Implant Considerations Syndesmosis Have pelvic forceps on back table May need longer plates than in small frag set: 1/3 tubular, compression or specialty fibula plate Bioresorbable screws

Case #1 Age: 81 Gender: Female Cause of Injury: Fall Fixation: 3.5mm LCP Lateral Distal Fibula Plate

Case #2 Age: 64 Gender: Female Cause of Injury: Fall Fixation: 3.5mm LCP Lateral Distal Fibula Plate

Summary Reviewed ankle anatomy Identified the indications & treatment goals for ORIF of ankle fractures Summarized the implant options

Thank You