Introduction:
The foot is a vital part that aids in mobility. The intrinsic structural design of the foot is made in such a way as to offer stability and to withhold the body weight. Any form of abnormality or deformity concerning the foot is distressing and, at the same time, disabling. Certain foot abnormalities are precipitated by birth, while some are acquired later in life. A flatfoot deformity is an anomalous foot deformity where the foot loses its normal structural and anatomic features. Normal foot anatomy accommodates arching in the foot’s undersurface, and this arching contributes to the even distribution of the body weight to all the foot bones. Thus, arching leverages the transmission of muscular forces from the leg to the underlying surface or ground, making movement possible. In flatfoot, the undersurface of the foot appears to be flat without appreciable arching, unlike the normal anatomy.
What Is Adult Acquired Flatfoot Deformity?
Adult-acquired flatfoot deformity (AAFD) is a highly prevalent foot condition where the person gradually and progressively loses the normal foot arching. This gradual arch collapse makes the undersurface of the foot flatter, interrupting the load distribution within the foot bones. Flatfoot deformity can also develop by birth, which is the congenital form, where the person is born with conditions that predispose one to have a collapsed foot arch. While adult-acquired flat foot deformity, as the name suggests, is acquired later in life, particularly during adulthood. The intensity and degree of the deformity elicit gradual inflation with age. The extent of deformity and flatness determines the level of functional deterioration of the foot. With the flattening of the foot arch, the anatomical position and relation of certain foot bones will get altered, further potentiating the deformity.
What Leads to the Development of Adult Acquired Flatfoot Deformity?
Adult-acquired flat foot deformity is often precipitated by abnormalities in the ligamentous foot structures that keep the bones and associated soft tissues in the intended position. The posterior tibial tendon is identified to be the crucial structural element that is responsible for stabilizing the foot arch. The posterior tibial tendon is a thick tissue strap extending from the calf region to the midfoot bones, where its terminal fibers are inserted.
Disease, dysfunction, or trauma to the posterior tibial tendon can bring in flatfoot deformities. Posterior tibial tendon dysfunction (dysfunctioning of the posterior tibial tendon, destabilizing the foot arch) is therefore considered to be a contributing factor for adult-acquired flat foot deformity.
Over time, the posterior tibial tendon may wear down, making it prone to tears and dysfunctions. Similarly, the condition may develop due to compromised blood flow to the posterior tibial tendon due to its curved trajectory. Compromised blood supply to the tendon detains the process of healing following trauma or injury, which further contributes to adult-acquired flatfoot deformity development.
Certain disease conditions enhance the risk for adult-acquired flat foot deformity. Some of them include the following:
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Diabetes (raised blood sugar level).
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Arthritis (joint tenderness).
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Obesity (overweight).
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Disease involving nerves and muscles.
What Are the Manifestations Associated With Adult Acquired Foot Deformity?
Routinely encountered manifestations associated with adult-acquired flatfoot deformity include the following:
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Tenderness and puffiness, particularly in the rear portion of the foot and ankle region.
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Anatomical deformation of the foot where the heel region tends to deviate outward.
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Deformation of the ankle joint.
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Stiffened Achilles tendon (heel cord extending across the heel and calf region of the foot).
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Compromised range of movements in hindfoot joints.
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Atypical turning of the foot.
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Collapsed arching of the foot.
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Trouble standing or walking for extended periods.
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Distorted alignment of the ankle with the foot base.
How Is Adult Acquired Flatfoot Deformity Managed?
Adult-acquired flatfoot deformity entails an interdisciplinary approach by taking into account various influential factors, like the extent of deformity, stage of the condition, patient’s general health status, and level of functional impairment. The concerned doctors plan the treatment strategies. Routinely preferred treatment modalities for adult-acquired flatfoot deformity include the following:
1. Rest: The affected foot is immobilized, with limited movements and offloading, which allows the posterior tibial tendon to repair, thereby restoring stability and functions. Immobilization alone is advised for adult-acquired flatfoot deformity of recent origin without severe deformity of the joint and foot. Walking boots are often advised to immobilize the affected foot.
2. Orthotic Devices: These are custom-made external devices that can correct malalignment of the foot and ankle resulting from the AAFD. Furthermore, it also extends support for the foot and aids in restoring the functional status. Cast boot walkers, shoe inserts, ankle brace, and ankle foot orthoses are the generally employed orthotic devices for adult-acquired flatfoot deformity. Therapy using orthotic devices is generally referred to as orthotic therapy.
3. Anti-inflammatory Therapy: Orthotic therapy is often coupled with pharmacological therapy using anti-inflammatory medicines to curb associated inflammatory changes like tenderness. These medications alleviate the soreness and discomfort associated with it. Non-steroidal Anti-inflammatory Drugs (NSAIDs), particularly Ibuprofen, are advised to reduce discomfort and inflammation, thereby offering symptomatic recovery.
4. Physiotherapy: Physiotherapy is recommended to enhance and augment muscular strength. Physical therapy improves joint function and reinforces the range of movement. The duration and type of physiotherapy intervention needed may differ with the severity and degree of flatfoot deformity. It is often coupled with other treatment interventions for better treatment outcomes.
5. Surgical Therapy: Surgical interventions are more extensive and therefore advised for only indicated cases where nonsurgical techniques fail to achieve desired treatment outcomes. Different surgical approaches are currently in practice for dealing with adult-acquired flatfoot deformity. Debridement of the inflamed portion of the posterior tendon lining is one such surgical intervention. Surgical interventions are also undertaken to reshape and realign the deformed foot bones through osteotomy techniques to restore their functional status.
Arthrodesis is another effective surgical modality where irreversibly deformed bones in the foot joints are made to fuse. This procedure offers greater stability but remarkably compromises the joint's movements. Ligament repair, ligament lengthening, tendon transfer, and muscle lengthening are other surgical techniques that are proven to be effective for adult-acquired flatfoot deformity. Ankle replacement is the final resort, where the irreversibly deformed ankle joint is extracted and substituted with metal joints that mimic the normal joint in function. These metal joints are surgically implanted into the foot in the intended position.
Conclusion:
Being a progressive and disabling condition, adult-acquired flatfoot deformity necessitates timely attention and effective intervention to check the disease progression. The earlier the treatment is sought, the greater the chance for functional recovery. As the stage advances, the complexity of the treatment modalities also increases. However, in most instances, conservative approaches can obtain appreciable outcomes. Reports demonstrate that only 10 percent of the cases may demand surgical correction, while the remaining cases can be dealt with conservative strategies. Conservative approaches like orthotic therapy, pharmacological therapy, and physical therapy, when advised simultaneously, offer appreciable symptomatic recovery by around 90 percent.
