The tibialis posterior is a muscle that originates from the posterior and medial side of the tibia (shin) and travels via its tendon behind the medial malleolus (inside ankle bone) before attaching to a bone on the inside of the foot called the navicular. The tibialis posterior acts primarily to roll the foot out, and also controls the rate at which the foot rolls in when it contacts the ground.
Injuries of this muscle and tendon complex generally occur in and around the tibialis posterior tendon rather than the muscle itself. The tendon of tibialis posterior is progressively loaded as the foot makes contact with the ground and the foot rolls in. In those people who have very poorly functioning feet resulting in large amounts of arch collapse, the tendon may actually be compressed (squashed) between the ground/shoe and the navicular. Running sports in particular place increased strain and compression on the tendon, which increase the risk of injury.
Many contributing factors have been identified as playing a role in tibialis posterior tendon injury. These factors include:
- Malalignment (poor foot posture)
- Hypermobility (increased joint movement),
- Ligamentous Laxity (overly elastic ligaments)
- Local trauma
- Changes in training technique and intensity
- Changes in playing surfaces
- Systemic illnesses such as Diabetes
- Increased BMI and
- Poor Footwear.
All of these factors may contribute to acute inflammation in the tibialis posterior tendon.
If left untreated, the acute inflammation of the tibialis posterior tendon can develop into chronic inflammation. This may result in degeneration of the tendon leading to tendinosis (a breaking down of the collagen within the tendon). In some instances we may see tears occurring within the tendon itself. These are generally referred to as intrasubstance tears.
The onset of symptoms of tibialis posterior tenosynovitis is usually gradual, and generally affects those between 30 and 40 years of age. The pain is typically not debilitating initially, but rapidly worsens with prolonged walking or standing. In the athletic cohort it can ultimately affect push off and drive.
In the clinic pain may be reproduced on palpation over the tendon as it courses behind the medial malleolus. Swelling is often present, being most pronounced in the part of the tendon around its insertion on the navicular. Pain on toe standing or heel walking is generally positive for a tibialis posterior injury.
The management of tibialis posterior tendinopathy includes the following:
- Reduce activity
- Non-steroidal anti-inflammatory drugs
- Careful attention to training modification. Stretching and warm up are critical in the acute phase of the injury
- Strengthening exercises
- Functional foot orthotic devices are also important to help improve function and influence the collapse of the foot – in effect reducing the load on the tendon
- Footwear changes to more supportive options
Ultimately tibialis posterior tendinopathy can result in significant disability and long term loss of function, especially if it is left untreated and associated issues arise such as the rupture of the spring ligament. If unsure, please make contact with us and let one of our podiatrists assess your foot.
