Progressive Collapsing Foot Deformity
Progressive Collapsing Foot Deformity, also know as Pes Planus, Flatfoot, or Adult Acquired Flatfoot Deformity, is a very common problem seen by orthopaedic surgeons. A flatfoot is one in which the arch is a bit flatter than population norms. This can be seen in people of all ages but is not always problematic. However in some people, flatfoot can become a painful problem, and this can occur at any age including childhood. The cause is multifactorial and has been linked to, diabetes, obesity, tendonitis, injuries, and many other contributing factors. Many people are born with a naturally flatter arch simply based on the shape of their bones and joints from genetic predisposition. Posterior tibial tendonitis a common cause of flatfoot deformity. The posterior tibial tendon normally functions to maintain the arch of the foot. With posterior tibial tendon dysfunction, the arch may collapse or a normal arch may become flat and painful. Sometimes a foot is flat from birth and eventually because the foot is so flat it starts to wear out the the tendons (posterior tibial tendon) and ligaments (deltoid and spring ligaments). Early in the disease process, conservative treatment modalities may help relieve pain and slow disease progression. However, once a deformity begins to progress, surgery may be beneficial to realign the foot and stop collapse. Several mitigating abnormalities lead to the development of this multiplanar misshapen foot with biomechanical dysfunction. Most commonly, a description of the planes of deformity includes forefoot varus, midfoot abductus, hindfoot valgus, and ankle valgus. These terms are used by surgeons to universally characterize changes in the shape of both the foot and the ankle. Usually, multiple incisions and procedures are needed to separately address each of these areas.
Conservative Treatment
Regardless of the stage of progressive flattening foot deformity, conservative treatment can sometimes be beneficial. Early on, pain relief may be obtained by resting the tendons and ligaments to resolve inflammation. This may be enhanced with physical therapy to strengthen the tendons and to improve postural control. Activity modification and resting the tendon with casting, booting, bracing, or an arch support may sometimes be beneficial. Oral and or topical anti-inflammatory medications, cryotherapy, and sometimes a steroid injection may be beneficial.
After Surgery
The recovery process from flatfoot correction varies depending on which procedures are necessary to correct the deformity. The first week after surgery is spent resting and elevating the foot to decrease swelling. Most patients prefer to go home although sometimes a one night stay in the hospital may be beneficial. Patients are discharged home in a splint, which is later converted to a cast in the office. Stitches are generally removed around 2-3 weeks. Usually, 6 weeks of non-weight bearing after surgery is followed by transition into a walking boot and for another six weeks. Mobilization while non-weight bearing may be assisted with crutches, a walker, or a rolling knee scooter. Patients are generally transitioned into a standard shoe around 12 weeks post-operatively. Physical therapy may be beneficial to regain strength, motion, and improve walking.
Historically, there were four stages of flatfoot deformity to help guide surgical decision-making:
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Stage I- Tendon Pain and Dysfunction Without Deformity
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Stage II- Flexible Foot Deformity
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Stage III- Rigid Foot Deformity
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Stage IV- Both Foot and Ankle Deformity
Surgical Intervention
When conservative treatment fails, operative intervention may be beneficial. There can be significant overlap between the stages outlined above, but staging can sometimes be helpful in determining the surgical techniques necessary to correct the problem.
A painful posterior tibial tendon (PTT) that is still functional may be seen early on. The tendon may or may not be salvageable. This can often be treated with repair of the PTT or transfer of the flexor digitorum longus tendon ('FDL tendon transfer') to replace the diseased PTT. The heel may be shifted towards the midline ('medial slide calcaneal osteotomy') to take tension off of the posterior tibial tendon and to realign the hind foot. Additionally, a 'lateral column lengthening' osteotomy of the calcaneus is sometimes performed. This osteotomy is done to push the foot back around in line with the knee and ankle in patients with a foot that points to the outside of the midline because it's so flat. It is necessary to perform these simultaneous balancing osteotomies to the foot to protect the transferred FDL tendon, which is weaker than the original PTT tendon. These additional procedures are tailored to each patient. Most of the time a 'gastrocnemius recession' is performed. The gastrocnemius muscle is almost always severely contracted with flatfoot conditions. This 'recession' or release is done through a small incision in the calf area to relax the tight contracted musculature. This is done in order to take tension off of the repair, to stop progression of the deformity, to decrease pain, and to help with ankle motion.
A 'Cotton osteotomy' of the medial cuneiform bone, or selective fusions of midfoot joints may be done to bring the 'medial column' or big toe are back down to the floor once the ankle and hind foot are corrected.
In a stiff or severe flatfoot deformity that has arthritis, it is often necessary to fuse arthritic joints in the foot to restore the alignment of the foot and to eliminate painful arthritis. These fusions may be done in combination with additional procedures used in earlier stages of the deformity to further improve alignment. The rebalancing will help eliminate pain in the foot, but also may serve as long term protection to the surrounding healthy joints including the ankle.
Once the foot is realigned through osteotomies and/or fusions, in addition to the 'FDL transfer', it may be beneficial to repair the ankle and foot ligaments on the medial side of the arch. This is often referred to as a 'deltoid or spring ligament repair'. This involves suture repair of the tissues and sometimes augmentation with implants to strengthen or replace diseased ligamentous tissue.
Later stages of progressive flattening foot deformity are characterized by the same problems as earlier stages, but unfortunately, the ankle joint may be involved in addition to the foot. This is a much bigger issue because this is now both a foot problem and an ankle problem. It can become more difficult to predictably correct both. With a chronic flatfoot, there may be an imbalance of forces at the ankle joint, which can progress to degenerative arthritis and malalignment of the ankle. The foot is treated similarly with fusions and balancing procedures. However, the ankle joint will need to be addressed as well. Typically, the ankle joint is treated with a fusion or an ankle replacement. Often times, with a long-standing deformity, one operation to address and realign the foot may be followed by a second operation to perform an ankle replacement in a staged manner.
80 year-old male: gastrocnemius recession, tibia bone graft harvest, subtalar fusion, PTT resection and FDL tendon transfer, deltoid lIgament repair, midfoot fusion
80 year-old male: gastrocnemius recession, tibia bone graft harvest, subtalar fusion, PTT resection and FDL tendon transfer, deltoid lIgament repair, midfoot fusion