Dysfunction of the tibialis posterior tendon is a common condition and a common cause of acquired flatfoot deformity in adults. Women older than 40 are most at risk. Patients present with pain and swelling of the medial hindfoot. Patients may also report a change in the shape of the foot or flattening of the foot. The foot develops a valgus heel (the heel rotates laterally when observed from behind), a flattened longitudinal arch, and an abducted forefoot. Conservative treatment includes non-steroidal anti-inflammatory drugs, rest, and immobilisation for acute inflammation; and orthoses to control the more chronic symptoms. Surgical treatment in the early stages is hindfoot osteotomy combined with tendon transfer. Arthrodesis of the hindfoot, and occasionally the ankle, is required in the surgical treatment of the later stages of tibialis posterior dysfunction.
As the name suggests, adult-acquired flatfoot occurs once musculoskeletal maturity is reached, and it can present for a number of reasons, though one stands out among the others. While fractures, dislocations, tendon lacerations, and other such traumatic events do contribute to adult-acquired flatfoot as a significant lower extremity disorder, as mentioned above, damage to the posterior tibial tendon is most often at the heart of adult-acquired flatfoot. One study further elaborates on the matter by concluding that ?60% of patients [presenting with posterior tibial tendon damage and adult-acquired flatfoot] were obese or had diabetes mellitus, hypertension, previous surgery or trauma to the medial foot, or treatment with steroids?.
The first stage represents inflammation and symptoms originating from an irritated posterior tibial tendon, which is still functional. Stage two is characterized by a change in the alignment of the foot noted on observation while standing (see above photos). The deformity is supple meaning the foot is freely movable and a ?normal? position can be restored by the examiner. Stage two is also associated with the inability to perform a single-leg heel rise. The third stage is dysfunction of the posterior tibial tendon is a flatfoot deformity that becomes stiff because of arthritis. Prolonged deformity causes irritation to the involved joints resulting in arthritis. The fourth phase is a flatfoot deformity either supple (stage two) or stiff (stage 3) with involvement of the ankle joint. This occurs when the deltoid ligament, the major supporting structure on the inside of the ankle, fails to provide support. The ankle becomes unstable and will demonstrate a tilted appearance on X-ray. Failure of the deltoid ligament results from an inward displacement of the weight bearing forces. When prolonged, this change can lead to ankle arthritis. The vast majority of patients with acquired adult flatfoot deformity are stage 2 by the time they seek treatment from a physician.
Perform a structural assessment of the foot and ankle. Check the ankle for alignment and position. When it comes to patients with severe PTTD, the deltoid has failed, causing an instability of the ankle and possible valgus of the ankle. This is a rare and difficult problem to address. However, if one misses it, it can lead to dire consequences and potential surgical failure. Check the heel alignment and position of the heel both loaded and during varus/valgus stress. Compare range of motion of the heel to the normal contralateral limb. Check alignment of the midtarsal joint for collapse and lateral deviation. Noting the level of lateral deviation in comparison to the contralateral limb is critical for surgical planning. Check midfoot alignment of the naviculocuneiform joints and metatarsocuneiform joints both for sag and hypermobility.
Non surgical Treatment
Nonoperative treatment of stage 1 and 2 acquired adult flatfoot deformity can be successful. General components of the treatment include the use of comfort shoes. Activity modification to avoid exacerbating activities. Weight loss if indicated. Specific components of treatment that over time can lead to marked improvement in symptoms include a high repetition, low resistance strengthening program. Appropriate bracing or a medial longitudinal arch support. If the posterior tibial tendon is intact, a series of exercises aimed at strengthening the elongated and dysfunctional tendon complex can be successful. In stage 2 deformities, this is combined with an ankle brace for a period of 2-3 months until the symptoms resolve. At this point, the patient is transitioned to an orthotic insert which may help to support the arch. In patients with stage 1 deformity it may be possible to use an arch support immediately.
If cast immobilization fails, surgery is the next alternative. Treatment goals include eliminating pain, halting deformity progression and improving mobility. Subtalar Arthroereisis, 15 minute outpatient procedure, may correct flexible flatfoot deformity (hyperpronation). The procedure involves placing an implant under the ankle joint (sinus tarsi) to prevent abnormal motion. Very little recovery time is required and it is completely reversible if necessary. Ask your Dallas foot doctor for more information about this exciting treatment possibility.