To restore congruency of posterior facet of subtalar joint
To restore height of calcaneum (and hence, Bohler’s angle)
To reduce width of calcaneum
To decompress sub-fibular space for peroneal tendons & prevent impingement
To realign tuberosity into valgus
To reduce calcaneocuboid joint, if involved
Alternatives include compression dressing & early mobilisation of ankle, GAMP, manipulation with Steinmann pin (go lateral to tendo Achilles for reduction of tongue type fractures), & Ex-Fix
Indications
Displaced intra-articular fracture (Sanders II or III), in a (young) healthy, non-smoker with normal ambulatory function & a sensate limb, with swelling reduced (wrinkle sign), & no fracture blisters (ie. usually 10-14 days post injury)
Sanders IV fractures usually treated closed or with ORIF & primary arthrodesis
Open fractures should be treated with initial debridement, especially of medial spike, & then delay 2-3 weeks for wound to stabilise.
Contraindications
Undisplaced or severely comminuted fracture, insensate limb (DM, other neuropathy, trauma), PVD, smoker, limited ambulation, inexperienced surgeon.
Preop
Xray- Lateral foot, AP/obl foot to assess anterior process & calc-cuboid joint, axial (Harris) view to assess varus alignment & heel width, Broden view to assess posterior facet congruency
CT in axial plane & semicoronal plane (perpendicular to posterior facet of calcaneum)
Consent including
contract to stop smoking, wound / deep infection, subtalar arthritis, calcaneo-cuboid arthritis, sural nerve / peroneal tendon injury
Technique
Tubigrip, elevation, analgesia, ice, CT, monitor for compartment syndrome. Discharge when comfortable & review skin for blisters (bad) & wrinkles (good) at 2 weeks. More difficult, but possible up to 5 weeks
GA / regional, lateral, IV anti’s, tourniquet, prep & drape leg free
L shaped incision with apex at heel tip & horizontal limb along junction of plantar skin & lateral heel skin, vertical limb midway between tendo Achilles & lateral malleolus. Straight down to bone, taking care to dissect out sural nerve at proximal & distal ends
Gently retract flap & perform subperiosteal dissection along lateral wall
Hold flap out of the way with K wires in talus, lateral malleolus & cuboid. Expose entire lateral wall, posterior facet & calcaneo-cuboid joint
Reflect lateral wall with osteotomy to expose posterior facet & medial side from within bone. Using a Steinmann pin in tuberosity fragment, distract it inferiorly, then lever into valgus, & then translate it medially
Use K wires to temporarily fix fragments, building onto medial wall & sustentacular fragment
Elevate the depressed posterior facet & pack the cavity with autologous BG or cement or bone substitute. Check reduction with II before replacing lateral wall
Then fix with low profile plate, 3.5 mm cortical screws, & extra screws if needed, directed into sustentaculum & buttressing posterior facet up
Most posterior screw into thickened bone at posterior aspect of calcaneum & most anterior screw into calcaneo-cuboid subchondral bone. Check with II that posterior facet reduced & heel not in varus
Close over drain. BKPoP slab.
If Sanders IV, carry out ORIF as above. May need to use tricortical iliac crest BG for large defects. Then use a burr to remove cartilage & subchondral bone from posterior facets of calcaneum & talus. Fill defect with autologous BG, & fuse with 6.5 mm cancellous screw from tip of heel up into talar neck. BKPoP NWB until union (10-12 weeks)
Postop
Remove drain at 24 – 48 hours. Check wound healing at 5 – 7 days, remove splint & allow active ROM ankle & subtalar joints. Leave sutures in for 3 weeks. NWB for 12 weeks. Use CAM walker in between physio sessions
? R/O metal after 12 months.
Results
Sanders
Type II 86% anatomical reduction, 73% good or excellent clinically
Type III 60% anatomical reduction, 70% good or excellent clinically
Type IV 73% failure
Complications
General systemic
General local – wound necrosis, dehiscence & infection, DVT
Specific – loss of position (early WB), malreduction, sural nerve & peroneal tendon injury
