Adult Acquired Flatfoot

Posterior tibialis tendon dysfunction is the most common cause of adult acquired flatfoot and is described in 4 stages ⁽⁴⁾.

• Stage 1- the tendon is intact and, to some degree, functioning (it can be inflamed).
• Stage 2- the tendon has become dysfunctional and the foot has developed an acquired flatfoot deformity, but the deformity is passively correctable.
• Stage 3- the foot deformity has become fixed and degenerative changes are seen in the subtalar joint.
• Stage 4- occurs when degenerative changes are also present in the ankle joint as well as the subtalar joint.

The main function of the posterior tibialis muscle is to provide dynamic stabilisation of the inner arch of the foot. This initial dysfunction can lead to a cascade of worsening pathological events, therefore early diagnosis may be important in delaying or preventing worsening symptoms associated with this condition.

The dysfunction of the posterior tibial tendon is a multifactorial process and can be difficult to attribute to a single cause. In many patients, there is a pre-existing flatfoot and many patients are also overweight, leading to increased stress on the tendon ⁽¹⁾.

Episodes of previous trauma, corticosteroid injections, arthritis, neuromuscular conditions and diabetes all increase the risk of the development of the condition ⁽¹⁾.

Adult acquired flatfoot is more common in middle-aged adults, particularly females with an elevated BMI, and has a reported prevalence in the UK between 3%-10% ⁽³⁾.

Your physiotherapist will ask for a history of your symptoms, proceeded by carrying out a clinical examination so that a precise and timely diagnosis can be given to ensure the most effective treatment can be put in place immediately. Your physiotherapist will work closely with you to set individualised treatment goals and will regularly reassess you to measure your progress and make any necessary modifications in your treatment.

Upon receiving your diagnosis, your clinician will educate you on the condition so that you can understand how you can help manage your symptoms. The physiotherapist will suggest activity modification strategies that will allow you to remain functional without causing symptom exacerbation. Additionally, your physiotherapist can suggest ways to help reduce pain and recommendations on pharmaceuticals that can make you more comfortable, collaborating with your GP where needed.

For patients wanting to achieve a high level of function or return to sport, we would encourage a consultation with a physiotherapist as you will likely require further progression beyond the advanced rehabilitation stage. Before returning to your sport, a rehabilitation programme should incorporate plyometric-based exercises; this might include things like jumping and running exercises ^{(5, 7)}.

As part of a comprehensive treatment approach, your musculoskeletal physiotherapist may also use a variety of other pain-relieving treatments to support symptom relief and recovery. Whilst recovering, you might benefit from a further assessment to ensure you are making progress and to establish an appropriate progression of treatment. Ongoing support and advice will allow you to self-manage and prevent future reoccurrence.

The most common intervention with this condition is the use of orthotics. These can be off the shelf insoles that are used to create support for the arch of the foot or custom insoles that are made specifically for your feet. It is advised to use these in conjunction with a tailored exercise programme.