Subtrochanteric arthroplasty has shown promise as an adjunct in patients suffering from mild or severe posterior tibial tendinitis insufficiency. The biomechanical mechanisms underlying the implant are not fully understood, and therefore, there are still questions in determining the best clinical indications for this device. However, older literature suggests that inferior talofibular fusion is similarly helpful in the correction of hindfoot deformity and provides protection for medial soft tissue reconstruction.
In milder type II posterior tibial tendon insufficiency, subtalar arthrodesis may avoid osteotomy of the heel. In patients with severe type II PTTD, additional toe flexor displacement and internal heel osteotomy can be added to correct residual deformities that cannot be corrected by subtalar arthroplasty alone. Definitive studies of clinical constructs are difficult to perform for a variety of reasons, however, there is reason to believe that good function, less trauma, and potentially shorter recovery times can be obtained with arthrodesis.
In the coming years, further studies will determine the role of constructs in posterior tibial insufficiency deformities. This article reviews the limited previous literature and presents the authors’ laboratory study of subacromial arthroplasty using an implant for the treatment of flexible flatfoot in adults.
Perspective: The current arthroplasty is a surgical procedure that has been developed over approximately 50 years to correct flexible flatfoot by altering the alignment of the subtalar joint. In Grice’s study on correction of pediatric flatfoot an external fusion of the subtalar joint with bone grafting in the tarsal sinus was used, but the patient developed late deformity [1].Haraldsson [2] inserted homogeneous cortical bone made into a wedge shape into the tarsal sinus to limit subtalar joint valgus, but no arthrodesis was performed.
In the United Kingdom, the first report of subtalar joint braking using a free-floating implant was made in 1977 [3]. Currently, the material used to make the joint brake insert can be sihcone, polyethylene, titanium, stainless steel or absorbable polymer material. The profiles of the inserts are varied and there are no studies to determine which inserts are better.
Few clinical studies have shown good results in pediatric and adult populations.Vedantam and coworkers [5] reported a 96% satisfaction rate in 140 feet of 78 pediatric patients with flexible flatfoot caused by neuromuscular pathology who underwent arthroplasty.Grannini and coworkers [6] reported on 21 children with bilateral flexible flatfoot who were treated with absorbable subacromial arthroplasty with a built-in device and the results of a 4-year follow-up.
In selected cases, Grannini also performed an additional Achilles tendon lengthening and a modified Kidner procedure. Viladot and colleagues [7] reported on 21 adult patients with stage II posterior tibial tendon insufficiency who underwent subtalar arthroplasty with additional tendonectomy of the posterior tibial tendon or transposition of the long toe flexor tendon or percutaneous Achilles tendon lengthening.
Follow-up time averaged more than 2 years, with significant improvement in hindfoot or ankle AOFAS scores.Needleman [8] reported on the use of standard surgery and subtalar arthroplasty for flexible flatfoot, with a mean follow-up of 44 months after surgery, and found significant improvement in radiographic parameters in patients with higher satisfaction (excluding 11 patients who had the built-in removed due to tarsal sinus pain, for a total of 28 patients who underwent built-in The removal of the built-in device was not associated with this complication.
In this study, it was not possible to make an independent evaluation of the role of the implant. A recent review of subtalar arthroplasty suggests that it can be used as an adjunct to MCO and FDL in the treatment of stage II posterior tibial tendon insufficiency without substantially increasing the complications of the procedure or the incidence of postoperative adverse events.