hindfoot (rearfoot) varus compensation

hindfoot (rearfoot) varus compensation

increased subtalar joint (STJ) pronation in a foot with hindfoot varus, bringing the foot to a plantigrade position just after heel contact; excess STJ pronation (if available) increases range of available forefoot motion on the hindfoot at the midtarsal joint, and the medial side of the foot is loaded during propulsion; the foot remains supinated and non-shock-absorptive throughout gait, or may compensate by developing forefoot valgus if there is insufficient STJ pronation to compensate for hindfoot varus (see Table 1)
Table 1: Features of rearfoot (hindfoot) varus
PresentationCharacteristics
Rigid (non-compensated) rearfoot varusExcess lateral shoe wear and distortion of shoe upper
Compensatory plantarflexion of first metatarsal with triggering of hallux or plantarflexion of hallux at 1 MTPJ and hyperextension of hallux at interphalangeal joint Figure 1
Mobile (compensated) rearfoot varusExcess compensatory STJ pronation with abduction of the feet during stance, especially in an obese patient
Overload callosity of plantar skin overlying 1 and 2 MTPJs
Callosity along medial border of forefoot and heel
Other features of excessive STJ pronation, as in mobile forefoot valgus; see Table 2 Figure 2 (B)

MTPJ, metatarsophalangeal joint; STJ, subtalar joint.

Figure 1: Pes cavus. A, Forefoot valgus, plantarflexed first ray. B, hindfoot varus. C(i) and (ii), sites for the hyperkeratotic lesions. D(i) and D(ii), clinical padding to deflect pressure. E(i) and (ii), in-shoe or insole padding. F, buttressed heel on shoe. This article was published in Neale's Disorders of the Foot, Lorimer, French, O'Donnell, Burrow, Wall, Copyright Elsevier, (2006).
Table 2: Features of forefoot valgus
PresentationCharacteristics
Rigid forefoot valgusRearfoot relationship to lower leg normal
Non-adaptation of foot during loading, in relation to imposed ground reaction forces under forefoot
Forefoot loads from medial to lateral, i.e. 1 MTPJ to 5 MTPJ (not 5 MTPJ to 1 MTPJ, as in the normal foot)
Little or no available MTJ supination
Excessive supination at the STJ
Reduced contact period pronation
External rotation of the leg with resultant lateral instability of the knee, ankle and STJ
Signs and symptomsIncreased height of the medial longitudinal arch
Calcaneal inversion
Lateral 'rock' during gait due to early stance-phase STJ supination (supinatory rock)
Loss of shock absorption mechanisms in lower limb with induced lower-back, hip, knee and shin pathologies
Reduced MTJ mobility
Retraction or clawing of the lesser toes and triggering of the hallux, with local shoe trauma
Hyperkeratoses of the plantar skin overlying the 1 and 5 MTPJs
Posterolateral calcaneal irritation
Difficulties in obtaining shoes that accommodate the foot deformity
Excess wear on lateral side of sole of shoe
Mobile forefoot valgusRearfoot relationship to lower leg normal
Forefoot loads from medial to lateral, i.e. 1 MTPJ to 5 MTPJ (not 5 MTPJ to 1 MTPJ, as in the normal foot)
The foot is mobile and distorts (pronates excessively) under load, so that the first ray dorsiflexes and the MTJ supinates
The MTPJ unlocks when supinated, with resultant forefoot hypermobility
Signs and symptomsHallux abductovalgus and/or hyperextension of hallux at interphalangeal joint
Lesser-toe deformities, including hammered second toe
Hyperkeratoses of the plantar skin overlying the 2, 3 and 4 MTPJs
Adductovarus of the fifth toe with dorsal and lateral hyperkeratosis
Tailor's bunion
Plantar digital neuritis
Plantar fasciitis and foot strain
Medial sesamoiditis
First metatarsal - medial cuneiform osteoarthritis
Compensatory calcaneal (STJ) pronation leading to Haglund's deformity, medial knee, shin and lower-back pain

MTJ, midtarsal joint; MTPJ, metatarsophalangeal joint; STJ, subtalar joint.

Figure 2: Rearfoot varus. A, uncompensated rearfoot varus. B, compensated rearfoot varus. C, pattern of hyperkeratotic lesions in the compensated foot. D and E, orthotic and shoe modification to control compensation. This article was published in Neale's Disorders of the Foot, Lorimer, French, O'Donnell, Burrow, Wall, Copyright Elsevier, (2006).