CMT Pes Cavus: Quantification of muscle strength and imbalance in neurogenic pes

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Foot Ankle Int. 2005 Jul;26(7):540-4.

Quantification of muscle strength and imbalance in neurogenic pes

cavus, compared to health controls, using hand-held dynamometry.

Burns J, Redmond A, Ouvrier R, Crosbie J.

School of Physiotherapy, The University of Sydney, East Street

Lidcombe, NSW 2141, Australia.

BACKGROUND: Pes cavus foot deformity in neuromuscular disease is

thought to be related to an imbalance of musculature around the foot

and ankle. The most common cause of neurogenic pes cavus is Charcot-

Marie-Tooth (CMT) disease. The aim of this investigation was to

objectively quantify muscle strength and imbalance using hand-held

dynamometry in patients diagnosed with CMT and pes cavus, compared to

healthy controls.

METHODS: Muscles responsible for inversion, eversion, plantarflexion,

and dorsiflexion of the foot and ankle were measured in 55 subjects

(11 CMT patients with a frank pes cavus, and 44 healthy controls with

normal feet) using the hand-held dynamometer (HHD). Test-

retest reliability of the HHD procedure also was determined for each

of the four muscle groups in the healthy controls.

RESULTS: Test-retest reliability of the HHD procedure was excellent

(ICC(3,1) = 0.88 to 0.95) and the measurement error was low (SEM =

0.3 to 0.7 kg). Patients with CMT were significantly weaker than

normal for all foot and ankle muscle groups tested (p < 0.001).

Strength ratios of inversion-to-eversion and plantarflexion-to-

dorsiflexion were significantly higher in the patients with CMT and

pes cavus compared to individuals with normal foot types (p > 0.01).

CONCLUSIONS: Hand-held dynamometry is an objective and reliable

instrument to measure muscle strength and imbalance in patients with

CMT and a pes cavus foot deformity.