As the calf muscles contract and a person rises up on tiptoes to bring the bodyweight over the heads of the metatarsals there is normally an inward deviation of the heel region. This inward deviation will not be present if there is a significant dysfunction of the tendon of the posterior tibial muscle and the patient may not be able to attain the position or can do so in part and with pain. The physio will move on to palpating the tendon insertion with the leg up on a plinth, searching for swelling, pain or tenderness. To test muscle power the physio will resist the inward and downward action of the foot.

Palpation of the length of the tendon during the muscle power testing is performed to check its integrity, followed by measuring the dorsiflexion of the ankle with a straight knee which is usually at least twenty degrees. Longer term flat foot can mean this is limited as the foot has been in a slight downward and outward position for long enough to develop a contracture, a tightening up of the soft tissues. The forefoot may also be subject to the development of an abnormal posture over time and should be reviewed. If the patient has pain, some deformity, problems with gait and managing footwear then treatment may be appropriate.

If the flat foot is painless and the person can walk well then normal shoes with or without insoles will suffice. Conservative management of posterior tibial tendon dysfunction involves resting, immobilisation, anti-inflammatories, physiotherapy and bracing or orthotics. This might be sufficient especially in elderly people as they do not put large forces through the area and may be less suitable for operative intervention. The initial stage of this condition presents primarily with pain, with acute inflammation of the tendon managed in plaster of Paris cast for a few weeks, which can be a weight bearing cast if walking is comfortable.

Settling down of the inflammatory and acute phase permits the use of in shoe orthotics to maintain foot posture and a referral to physiotherapy to increase joint ranges of movement and develop increased strength. The rear foot posture can be controlled more precisely if a flexible and painful dysfunction develops by using an ankle foot orthosis or AFO. The next stage of dysfunction, an increasingly rigid deformity, can be managed by more extensive and customised bracing which can extend to above the knee. Such conservative forms of management are the choice for individuals who demand less physically from their feet.

In the earlier stages of more acute dysfunction of the tendon surgical management entails the tendon sheath being opened to release it, a debridement (cleaning up) of the local area and repairs to the body of the tendon. After operation the patient is typically three weeks or so in a below knee cast, with this operation performed in the hope of stopping progression of the condition. More severe foot dysfunction forces the surgeon to choose from a very large number of operative options. There is no agreed surgical management of this phase and a good outcome is hard to ensure.

If the tendon is ruptured then the ends may be cleaned up and a repair done end to end, or if the tendon has detached from its insertion it can be reattached to the navicular bone. In more complex repairs the tendons of other nearby muscles can be detached and used to reinforce the function of the tibialis posterior muscle. An osteotomy, a corrective bony operation designed to realign the bony anatomy, can be performed on the heel bone or calcaneum to restore more normal alignment, decrease the stresses on the spring and plantar ligaments and allows any soft tissue operative changes to suffer decreased stresses.

Overall, surgery aims to achieve a painless foot which can adapt flat to the ground and which can wear shoes easily. Surgery can result either in an under correction of the deformity or an over correction and great care must be taken in aligning the many components of an appropriate foot posture. Initial surgery is to prevent the progression of the tendon inflammation to eventual rupture.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about physiotherapy, physiotherapy, physiotherapists in Birmingham, back pain, orthopaedic conditions, neck pain and injury management. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.

Tags: , ,