Definition
Rockerbottom foot / Persian Slipper Foot
Epidemiology
Uncommon
50% bilateral
Doesn't delay walking
- may present in toddler with callus under talus head
Associations
Congenital anomalies
- CNS disorders
- spina bifida & diastematomyelia ~10%
- arthrogryposis
- neurofibromatosis
- CDH
- Trisomy 15-18
Pathogenesis
Uncertain
- result of muscle imbalance
- arrested foot development
Theories
- contracture of T Achilles posteriorly pulling calcaneus into equinus
- contracture EDL anteriorly pulling navicular dorsally
- absence of plantar intrinsics
Pathology
Bony
Calcaneus
- in equinus / valgus / laterally displaced
- sustentaculum tali hypoplastic & doesn't support head
Talus
- hypoplastic & in plantar flexion
- only posterior 1/3 articulating with tibia
Navicular
- displaced dorsally onto talus neck
- wedge shaped
Forefoot abducted
Tendons
Posterior
- triceps contracted
Anterior
- T anterior, long extensors & peronei are contracted
T posterior & peronei subluxed anteriorly / become dorsiflexors
Joints
STJ facets abnormal
CCJ abnormal
Ligaments
Dorsal ligaments contracted
Interosseous Talocalcaneal Ligaments / Dorsal TN
- thickened and contracted
Attenuated spring ligament
Clinical Features
Plantar aspect of foot convex
- rocker-bottom appearance
Hindfoot
- heel in fixed equinus
- key differential positional calcaneovalgus
Forefoot
- dorsiflexed
- abducted
Head of talus prominent
- palpable medially in sole
Plus
- medial column long & convex
- lateral column abducted
- tight tendoachilles
Xray
Lateral
- talus vertical
- calcaneum equinus
- increased talo-calcaneal angle / near 90o
- TNJ dislocated
Maximum Dorsiflexion view
- fixed equinus, talus still vertical
Maximum Plantarflexion view
- irreducibility of midfoot onto hindfoot
- relationship of talus to navicular fixed & rigid
DDx
1. Severe positional calcaneovalgus
2. Severe idiopathic flatfoot (with oblique talus)
- can reduce the TNJ with DF
3. Valgus everted foot of CP
4. Overcorrection of CTEV with broken midfoot
Management
Non-operative
Casting
Reverse Ponseti technique
- some good results reported
- stretches tissue preoperatively
Operative
Aims
Correct hindfoot equinus
Correct forefoot dorsiflexion
Reduce dislocated TNJ
Issues
One or two stage / usually one stage
Timing
Between 12 and 18 months
Surgery
Cincinnati incision
- patient prone
- from medial cuneiform to lateral malleolus
Release hindfoot equinus
- T Achilles lengthening
- posterior capsulotomy AJ & STJ
- release interosseous talo-calcaneal ligament
- release CFL / PTFL
Reduce TNJ
- capsulotomy TNJ & locate head
- K wire
Release forefoot dorsiflexion
- lengthening of EDL, EHL & T Ant
- ± calcaneocuboid capsulotomies
Stabilise
- calcaneum fixed to tibia via wire through heel
- 2nd wire across TNJ in PF
- ± Wire across CCJ
Tibialis Anterior usually transferred to neck talus
Late Presenting
Age 2-6
- subtalar fusion if painful
- Grice arthrodesis
Adolescent
- triple arthrodesis