Types
1. Grice
2. Lambrinudi
3. Dunn
Grice
Definition
Extra-articular STJ fusion
- lateral bony block in sinus tarsi
- prevents valgus deformity
- allows undisturbed foot growth
Indication
Flexible valgus hindfoot in children 4 - 12
Polio
Contra-indications
Fixed hindfoot
CP - high failure rate
Varus - high failure rate
Technique
Ollier's incision
- oblique lateral incision
- tip of fibula to base 4th MT
Superficial dissection
- between peroneal brevis and tertius
- elevate EDB
- expose sinus tarsi
- remove all ST from talus and calcaneus
- grooves in calcaneum and talus
- no articular surface is exposed
Bone graft
- reduce hindfoot
- cancellous iliac (no structural)
- tibial wedge (structural)
- may supplement with metalwork / K wires
Post operative
- cast for 6/52
Dennyson and Fulford Modification of Grice
Cannulated screw
- across talus and bone block and into calcaneum
Complications
Pseudoarthrosis
Graft slippage / residual deformity
Overcorrection into varus
Lambrinudi
Concept
Plantar flexion of the talus
- is eventually limited by abutment of the posterior process of the talus
- against the lower end of the tibia
Plantigrade forefoot is fused to the maximally flexed talus
Indications
Isolated fixed equinus deformity in patient older than 10
- tight triceps surae / weak dorsiflexors
- polio most common cause in past
Argument exists that the procedure is not suitable for flail footdrop
- recurrence of deformity due to stretching of the dorsal and anterior soft tissues
- need strong dorsal capsule +/- dorsal tendon transfers
Contraindications
Ankle joint instability - will be worsened by the procedure as narrow posterior part of talus is in the mortise
Painful pre-existing tibiotalar osteoarthritis
Severe knee or hip instability such that a brace must be worn
Age < 11 years
Operative Technique
Preoperative planning is essential
- lateral X-Ray taken with foot in extreme equinus
- tracing made and sectioned along lines of subtalar and midtarsal joints and size of wedges calculated
- wedges calculated so that forefoot is plantigrade or up to 10o of equinus in relation to the tibia
- hindfoot in neutral or up to 5o valgus
- greater equinus if need to compensate for short limb
Ollier incision
- expose sinus tarsi by elevate EDB
- Z sectioning of peroneal tendons
- CFL divided
Talar osteotomy done parallel to transverse axis of ankle joint with talus in extreme equinus
- microsagittal saw
- correct any hindfoot deformity by resecting appropriate calcaneal wedge
V shaped trough fashioned in lower part of proximal navicular
- denude calcaneocuboid joint of cartilage
- sharp distal margin of remaining talus wedged into trough in navicular
K wire CCJ and TNJ
- talus is locked in complete equinus such that no more plantar flexion can occur
N.B. talonavicular pseudarthrosis is a common cause of failure
- ensure talus well medial in trough
- adequate width and depth of trough to allow sufficient bone contact
Postoperative management
- long leg POP 6 weeks (NWB)
- short leg POP 6 weeks (NWB)
- if united (attention to talonavicular joint) then remove cast and weight bear
- if not united then walking cast until united
Complications
Instability
Deformity
- positioning of talus medially in navicular trough crucial
- loss of correction of up to 20o in 10-20% of cases
- post-operative supination deformity
Painful ankle OA - will develop with instability or talar AVN / often asymptomatic
Talar AVN - avoided by leaving anterior ankle capsule intact
Pseudarthrosis
- vast majority talonavicular
- risk factors: early weight bearing, no K-wire fixation
Dunn Arthrodesis
Concept
Variant of triple arthrodesis
- adapted to improve muscle balance in paralytic conditions with a predominant weakness of the triceps surae (calcaneus)
Technique
Navicular and variable portion of talar head and neck resected
- foot is displaced posteriorly on remaining talus
- lever arm of triceps surae improved
- talus fused to cuneiforms