Surgical Treatment of Hyperpronation Using an Extra-Osseous TaloTarsal Stabilization Device

What is it about?

The purpose of this study was to determine radiographic correction of angular relationships between the hindfoot and forefoot osseous structures following an extraosseous talotarsal stabilization procedure with HyProCure® in patients diagnosed with reducible/partial dislocation of the talus on the tarsal mechanism (RTTD).

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Why is it important?

Recurrent/reducible talotarsal dislocation (partial) is a dynamic deformity where the talus displaces on one or more of the articular facets of the tarsal mechanism. Radiographic evidence of this pathology includes an abnormally high talar second metatarsal angle (transverse plane) on weightbearing AP/DP radiographs and a higher than normal talar declination angle, obliterated sinus tarsi and navicular drop (sagittal plane) in lateral weightbearing radiographs. Therefore, treatment methods for RTTD should show restoration of the angular measurements to within accepted normals in order to prove their efficacy in correcting the pathology. Patients & Methods 70 patients (95 feet) who were diagnosed with RTTD in at least one plane and underwent an EOTTS procedure with HyProCure® as a stand-alone procedure.  All 95 feet demonstrated a transverse plane deformity, while only 65 of the 95 feet showed evidence of the deformity in the sagittal plane.  Mean age at the time of surgery was 58 (range 22 – 85 years).  Angular correction was determined through a comparison of pre- and postoperative weightbearing radiographs.  Postoperative radiographs were taken at an average follow-up period of 17 days. Results Normalization of the talar second metatarsal angle on the AP view.  Normalization of the talar declination angle on the sagittal view.  No effect on the calcaneal inclination angle.  Shows both transverse and sagittal plane correction/stabilization of the talotarsal mechanism and therefore also frontal plane correction.  Findings: Talar 2nd Metatarsal Angle AP radiograph o Average pre-op T2M angle: 24.8 degrees o Average post-op T2M angle: 5.8 degrees o Mean decrease = 19 degrees (77%)  Findings: Talar Declination Angle Lateral radiograph o Average pre-op TD angle: 25.1 degrees o Average post-op: 19.4 degrees o Mean decrease: 5.7 degrees (23%)  No overcorrection was shown for feet with preoperative normal radiographic measurements in the sagittal plane.

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