Arthrodesis

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