A rare case of a ball and socket ankle joint
============================================

* Roland Fernandes

## Description

A 50-year-old otherwise well gentleman presented with mild pain and stiffness in his right ankle. Remarkably, radiographs revealed gross congenital deformities. The ankle mortice was semicircular and the subtalar joints fused (figure 1). There were only three metatarsals. The bases of the proximal phalanges of the first and second toes were fused and articulated with the head of the first metatarsal (figure 2). The ball and socket ankle joint was first described in English literature by Lamb in 1958.1 The aetiology of this abnormality is most often congenital but can be acquired due to poliomyelitis or postsubtalar arthrodesis.2 It is most often found in association with other congenital deformities which can result in leg length discrepancy, instability, pain and stiffness. However, the reports suggest although the aforementioned symptoms can occur, what is surprising is the lack of symptoms that can occur with this malformation. The patient had mild stiffness and pain which did not impact upon his lifestyle. On examination, he had a 2 cm leg length discrepancy, which the authors treated with an orthotic supplement. The possible future operative interventions include fusion of the ankle joint should his symptoms progress to be more debilitating.

![Figure 1](http://casereports.bmj.com/https://casereports.bmj.com/content/casereports/2011/bcr.10.2011.4919/F1.medium.gif)

[Figure 1](http://casereports.bmj.com/content/2011/bcr.10.2011.4919/F1)

Figure 1 
Radiograph of ankle joint.

![Figure 2](http://casereports.bmj.com/https://casereports.bmj.com/content/casereports/2011/bcr.10.2011.4919/F2.medium.gif)

[Figure 2](http://casereports.bmj.com/content/2011/bcr.10.2011.4919/F2)

Figure 2 
Radiograph of foot bones.

## Footnotes

*   Competing interests None.

*   Patient consent Obtained.

## References

1.  Lamb D. The ball and socket ankle joint; a congenital abnormality. J Bone Joint Surg Br 1958;40-B:240–3.
    
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2.  Pistoi F, Ozonoff MB, Wintz P. Ball-and-socket ankle joint. Skeletal radiol 1987;16:447–51.
    
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