Tibialis anterior rerouting combined with calcaneal lengthening osteotomy as a single-stage reconstruction of symptomatic flexible flatfoot in children and adolescents

Patients were evaluated preoperatively, both generally, locally, and radiologically. Generally, to assess body build, fitness for surgery, and associated neuromuscular disorders or syndromes. Locally, to evaluate the type of flatfoot, whether flexible or rigid using the Hubscher maneuver (Jack’s test) and the soft tissue condition of the foot.

Radiologically, standing anteroposterior (AP) and lateral foot X-rays were obtained to measure the preoperative parameters, including the standing talo-first metatarsal angle and talonavicular coverage angle in the AP view and talo-first metatarsal angle and calcaneal pitch angle in the lateral view.

In bilateral cases, we operated each side separately with a 4 to 6-month interval.

Surgeries were done with patients in the supine position under general anesthesia. Antibiotic prophylaxis, third generation cephalosporins, was used two hours before the time of anesthesia induction at a dose of 50 mg/kg. A pneumatic tourniquet was used in all patients.

A 5 to 6 cm lateral longitudinal incision was centered over the calcaneocuboid joint. The sural and superficial branches of the peroneal nerve were protected. Dissection took place between the extensor digitorum brevis dorsally and the peroneal muscles plantarly. The calcaneocuboid joint (CCJ) was determined without joint capsule opening. The CCJ was fixed using 1.5 mm K-wire inserted from distal to proximal and stopped before the planned osteotomy site to prevent subluxation of the CCJ while opening the osteotomy site. Z-lengthening of the peroneus brevis was performed. Localization of the osteotomy site was done by the insertion of a reference K-wire about 1–1.5 cm proximal to the calcaneocuboid joint and parallel to it. The osteotomy was done between the anterior and middle facet of the calcaneus using an oscillating saw just proximal to the reference wire and under C-arm control. The osteotomy site was then opened using a lamina spreader up to the maximum opening to determine the width of the graft needed. A tricortical trapezoidal-shaped bone graft was taken from the ipsilateral iliac crest. The width of the graft ranged from 8 to 12 mm at one edge and 4 to 6 mm on the opposite edge. The graft was inserted and well-fitted into the osteotomy site. Although the graft was inherently stable, additional stability was added using a single staple to prevent dislodgement of the graft, Fig. 1.

An 8 to 10 cm incision was made just medial to the tibialis anterior tendon from the first metatarsal base distally to the talonavicular joint proximally. The incision was deepened, and the tibialis anterior tendon was freed up along its route, keeping it attached to its insertion. A U-shaped osteoperiosteal flap was made on the medial side of foot, extending over the capsule and overlying the talonavicular joint, navicular bone, navicular-medial cuneiform joint and medial cuneiform bone keeping the flab attached at the planter side. A gutter was then created beneath the navicular tuberosity, and the tibialis anterior tendon was then pulled down into this gutter and stitched to soft tissues beneath the talar head. Two K-wires were inserted into the navicular as anchors to prevent slippage of the tendon back till soft tissue healing. The U-shaped osteoperiosteal flap was then sutured back into its place over the tibialis anterior tendon keeping the tendon in the gutter and preventing it from dislocating, Fig. 2.

After completion of calcaneal lengthening and tibialis anterior rerouting, testing for ankle dorsiflexion was done. The ankle should be dorsiflexed to 10–15 degrees. In cases with ankle contracture, the Silfverskiold test was used to evaluate the cause of the contracture, whether it was gastrocnemius muscle or the Achilles tendon. Patients with positive Silfverskiold test underwent fractional lengthening of the gastrocnemius muscle through a separate posterior approach, Fig. 3.

After completion of the surgical procedures, the tourniquet was deflated, and proper hemostasis was done before wound closure and application of a below well-padded knee cast.

Immediate postoperative foot X-rays were done to assess the degree of correction of the radiological parameters. Postoperative antibiotic prophylaxis was given for 3 days in the form of third generation cephalosporins with a dose of 50 mg/kg/day. Patients were discharged from the hospital on the second day postoperative. Follow-up was done in the outpatient clinic two weeks postoperatively for wound assessment, stitches removal, and application of a new below-knee cast. Six weeks later, the cast was removed, and new foot X-rays were done to assess the healing of the calcaneal osteotomy. Below-knee walking cast was then applied and partial weight bearing was allowed for 4 weeks. This was followed by cast removal and full weight-bearing. Regular follow-up visits were advised every 6 months.

The American Orthopaedic Foot and Ankle Society (AOFAS) score [22] was utilized to assess the functional results of patients. Results were excellent with a score of 85 or more, good with a score of 75–84, fair when the score was 60–74, and bad when the score was less than 60.

Data were analyzed using IBM SPSS software package version 20.0. (Armonk, NY: IBM Corp). Continuous variables were represented as mean ± SD. Qualitative data were represented as numbers and percentages. Wilcoxon signed-rank test was utilized to compare quantitative variables which were not normally distributed. Results were judged significant at a 5% level.

This study included 28 feet in 16 patients, with a mean age of 11.6 ± 2.1 (range, 9–14.5) years. Eight (50%) patients were males and eight (50%) were females. The affected side was bilateral in 12 (75%) patients, right in 3 (18.8%) patients, and left in 1 (6.2%) patient. The main complaint was pain in 13 (46.4%) feet, cosmetic issues in 3 (10.7%) feet, and pain and cosmetic issues in 12 (42.9%) feet.

The average preoperative AOFAS score was 51.6 ± 5.5 (range, 42–61).

In 25 (89.3%) feet, there was ankle contracture with a positive Silfverskiold test that necessitated fractional lengthening of the gastrocnemius muscle through a separate posterior approach. The remaining 3 (10.7%) feet had no ankle contracture, Table 1.

The talonavicular coverage angle decreased from 13.6 ± 4.4° (range, 5–25) preoperatively to 3.9 ± 3° (range, 0–10) postoperatively, P < 0.001. The AP talo-first metatarsal angle reduced from 16.9 ± 4.4° (range, 10–25) preoperatively to 4.5 ± 3.6° (range, 0–15) postoperatively, P < 0.001. The lateral talo-first metatarsal angle decreased from 19.2 ± 4.9° (range, 10–30) preoperatively to 4.6 ± 3.2° (range, 0–12) postoperatively, P < 0.001. The calcaneal pitch angle increased from 9.6 ± 1.9° (range, 5–13) preoperatively to 23.8 ± 4.8° (range, 12–30) postoperatively, P < 0.001, Table 2, Fig. 4.

No major complications developed. Three feet got superficial wound infection which was managed by dressing and antibiotics according to culture and sensitivity. Five feet developed hardware irritation from the medial K-wires that were removed after a sufficient period for complete soft tissue healing (4–6 months postoperatively).