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Useful imaging includes MRI which is particularly useful in describing bone bruising and other osteo-chondral pathology that may not show on x-ray. Injection of local anaesthetic is useful in confirming the diagnosis with atypi- cal cases. Injection of corticosteroid is useful in resistant cases and may be best done under CT guidance in order to be sure of getting right into the sinus. Differential diagnosis is covered in the preceding article, but particular thought needs to be given to the list in box 1.

©1999 Primal Pictures Ltd

Figure 2: Sagittal section of the right foot through the second toe from the lateral side

Sinus tarsi tunnel and enclosed ligaments

Proprioceptive retraining with early incorporation of sports specific activity is central to all exercise prescription.

Orthotics can be used, particularly for pronated foot types as an adjunct to rehabilitation. Supinated foot types may benefit from orthotic prescription but will almost definitely require shock absorbing insoles. These interventions will be deter- mined by the contribution of the foot

type to the presentation, the demands of the sport, and the abil- ity of the individual to achieve adequate control through neuro- muscular retraining.

Biomechanical assessment/repetitive loading Assessment of the biomechanical contribution to the presentation is particularly critical in insidious onset STS but is also relevant in post-traumatic presentation. The key is to recognise and describe hyper-mobility and hypo-mobility occurring on three levels. ● Intra-articular: hypo or hyper-mobility of the joint may exist either separately or in combination ● Inter-articular: stiffness or uncontrolled laxity of the talo- crural, inferior tibio-fibular or transverse tarsal joints will direct- ly compromise the function of the STJ. Hypo-mobility of adjacent joints will result in greater forces being transmitted through the sub-talar joint while uncontrolled hyper-mobility compromises the whole region ● Regional: poor core stability, hip control or hip/knee/foot alignment existing in isolation or combined with excessive prona- tion or supination can be a significant factor in presentation

Hypo-mobility is treated best by:

1. articular manual directed at restoring normal movement of the STJ and surrounding joints or indeed those with a therapy:

peripheral influence on the joint (eg. hip)

2. myofascial techniques:

3. self-stretching strategies:

which may include trigger point manipulation, specific soft tissue mobilisation, proprioceptive neuro- muscular facilitation techniques to improve range or recruitment, or friction massage to accessible tissue

of a developmental, mobilising or preparatory nature

Hyper-mobility is best dealt with by: 1. muscle stability

retraining:

This can be augmented with 2. proprioceptive

taping:

3. restrictive taping: traditional tape procedures used to restrict movement of the joint in particular directions 4. orthoses:

5. ankle bracing (eg. may be useful to improve proprioception and mechanical support Aircast brace):

These adjuncts may be required on a temporary or permanent basis Table 1: Resolution of hyper and hypo-mobility SportEX 17

used to improve the control of pronation or supination where excesses of these are identified and deemed to be significant factors in the presentation.

Other aspects A full assessment would include evaluation of the soft tissues around the area, somatic lumbar referral, adverse neural dynamics of the superior and inferior tibio-fibular joints and sports specific aspects of the presentation.

Conclusion Sinus tarsi syndrome is a complex and difficult clinical entity to treat but with careful multi-factorial assessment and a comprehen- sive rehabilitation programme, a good outcome can be achieved.

Dylan Morrissey, MSc, MMACP, MCSP, is a specialist physiothera- pist at Mile End Hospital and Queen Mary and Westfield Hospital’s academic department of sports medicine. He is chief physiotherapist to the London Leopards Basketball club and he lectures widely on sports physiotherapy.

the key to restabilisation is retraining of local eccentric muscle function within the context of optimal hip/

knee/foot alignment on a background of adequate core stability. The amount of work to be directed at each of these areas is determined by the relative contributions of each of these components to the presentation

used to influence the activation of the surrounding musculature in an inhibitory or excitatory fashion