Adult acquired flatfoot

Last evidence check March 2011

The diagnosis of adult acquired flatfoot is made clinically. If there is no controversy about diagnosis or management we do not routinely obtain radiographs. However, in many patients there is a need to assess the joints and alignment for treatment planning, and in some there may be the possibility of inflammatory arthropathy or a tarsal coalition.

The standard plain films are:

On these views we assess the following parameters:

Younger (2005) studied the ability of radiographic measurements to distinguish between symptomatic flatfeet and controls. On the lateral radiograph, talo-first metatarsal angle, calcaneal pitch and medial cuneiform - fifth MT height were significantly different from controls. On the AP radiograph, talar head uncovering was the only measurement that was significantly different, and its inter- and intra-observer reliability was poor. The lateral talo-first metatarsal angle was the best discriminant between patients and controls, with an interobserver correlation of 0.83 and an intraobserver correlation of 0.75.

If we are planning surgery, or if there is any other need to assess the tendons and ligaments, we obtain an MR scan. Ultrasonography has also been described and is probably of equal accuracy to MRI, provided expertise and suitable equipment are available.

CT shows bony changes well, but does not show soft tissues clearly.

MR shows:

Conti et al (1992) classified the MR appearances:

Conti et al found that the MR appearances were a better guide to outcome than surgical findings. In particular tendon transfers were significantly more successful in type 1 tendons, but tendons graded type 1 by the surgeon were graded type 2 by MR in 10/17 patients - intra-operative assessment may lead to inappropriate choice of treatment.

Chhabra (2011) offers an extensive and well-illustrated review of MR findings and the realtionship to clinical staging.