Revision Total Ankle Replacement

Journal of Bone and Joint Surgery Essential Surgical Techniques January 2016,vol 4 Mayerson and Aiyer et al Institute of Foot and Ankle Reconst

Baltimore

Presenter : Dr Saumya Agarwal

Junior resident Dept of Orthopaedics J.N. Medical College and Dr. Prabhakar Kore Hospital and MRC, Belgaum

INTRODUCTION

• Failure rates of Total Ankle Replacement – 10% to 30% - over 10 yrs

• A recent meta-analysis – 317 TAR – failure rate of 12% @ 6 yrs

• Another meta-analysis - 852 patients – 24% had poor result

• 5year survivorship rate – 78%• 10 year survivorship rate – 77%

• Study describes approach – failed total ankle replacement – goal of best salvaging the joint with a revision arthroplasty

INDICATIONS

• Loosening and subsidence of talar component - main

• Gross dissolution of talus – previously considered a contra-indication

• Technique described here can manage

• Talar component subsides posteriorly – leads to angulation and deformation

• Patient must have good range of motion (radiographs in flexion and extension)

CONTRA-INDICATIONS

• Chronic pain

• Recent/ongoing infection

• Anterior soft tissue envelope is severely scarred

• Prior wound healing difficulty in anterior aspect of ankle

INCISION AND EXPOSURE

• Supine position

• Employ prior anterior midline incision

• Protect branch of superficial peroneal nerve

• Incise extensor retinaculum completely upto proximal aspect of talonavicular joint

• Enter between tibialis anterior and extensor hallucis longus tendon

• Expose tibia

• Incise ankle joint capsule

• Remove the heterotopic bone till prosthesis is visible

Removal of Talar Component

• Place curved osteotome under interface between talus and talar component

• Lift the talar component off

• Not to gouge the talus b’coz it may be helpful to insert threaded insertion guide into talus to facilitate removal

• Extract the polyethylene

Removal of Tibial Component

• Place osteotome at interface between tibial component and tibial osseous cortex

• Disengage the tibial component from osseous interface

• Technique preserves majority of anterior tibial cortical rim for support of revision prosthesis

Make Tibial Bone Cut

• Tibial cuts can be made proximal or distal to tibial osseous defects

• Distal tibial cuts limits joint elevation - facilitate bone preservation

• proximal tibial cuts leads to joint line elevation

• Insert 3.5mm guide pin into proximal tibial tubercle

• Attach tibial alignment guide

• Attach cutting guide to tibial alignment jig

• Cut should be perpendicular to mechanical axis

• Drill the proximal 2 holes on either side of tibial cutting jig

• Place pins in proximal 2 holes to protect malleoli from excursion of saw blade

• Make the tibial cut and remove the cutting guide

Make Talar Bone Cut

• Attach the talar cutting block to tibial alignment guide

Limited amount of bone should be resected from talus

Slide cutting block until it is flush with talar surface

• Place pins to lock talar cutting block into desired position

• Place a saw through distal slot of guide to perform talar cut

• Freehand technique to make the talar cut

• Place a lamina spreader into wound to distract the joint

• This aids with fluoroscopic visualization of joint to ensure that bone cuts and joint preparation are adequate

• Evaluate status of osseous surfaces to ascertain whether grafting or cementing is necessary to support the revision components

Managing Loosening & Cavitary Defects

If there is substantial bone loss around tibia after component removal, consider impaction bone grafting, as better bone quality makes it easier to obtain a press fit and allow immediate weight bearing.

Place Trial Components

• Insert tibial and talar trials and appropriately sized polyethlene at the same time

• Lock the talar trial with pins placed medially and laterally on anterior edge

• Check the fluoroscopic position of trial components and check complete range of motion to ascertain stability

• Drill holes for tibial component keel and then remove tibial trial

• Drill holes for talar component keel and then remove talar trial

• Thoroughly irrigate the wound

Cementing Technique

• In revision settings, manual cement insertion is important because there is no medullary canal to work around

Results

• 41 patients

• Mean time b/w TAR & revision TAR – 51 months

• Talar subsidence – most common (63%)

• Subtalar arthrodesis – 54%

• Arc of motion improved 5°, i.e., to 23° post-op

• 41 34 retained TAR 5 revision arthrodesis 2 amputation

Mean follow up time - 49 months

• AOFAS score 65 points

• VAS 4.4 points

• Revised foot function index score – 68% excellent results

• 73% return to their prior job

• only 44% able to return to previous activity level

Pitfalls & Challenges

• Many patients with previous TAR, have implants from syndesmotic arthrodesis or in the medial malleolus

• These screws should be left in place, to prevent #

• Implants that cross tibia should be removed to facilitate correct placement of tibial component

Take Home Message

Revision Total Ankle Replacement is better than Arthrodesis in failed Primary Total Ankle Replacement