MINI BONE BLOCK DISTRACTION SUBTALAR ARTHRODESIS IN THE MANAGEMENT OF ACQUIRED ADULT FLAT FOOT WITH SUBTALAR ARTHRITIS: EVALUATION OF THE RESULTS AT A MINIMUM 5 YEARS FOLLOW-UP

Abstract

Introduction: In situ subtalar arthrodesis cannot restore anatomical shape of the hindfoot in severe flat foot deformities. Purpose of this paper is to evaluate the result of 250 feet consecutively operated by subtalar arthrodesis with distraction and insertion of a mini structural bone block (SAMBB).

Material and Methods: 178 patients (250 feet), mean age 55+/−11 years affected by acquired adult flat foot with subtalar arthritis were evaluated clinically and radiographically and selected to receive SAMBB.

Arthrodesis was performed through a 2.5 cm incision, with partial cartilage removal and insertion of a structural corticocancellous block (2 × 1cm), harvested from the proximal ipsilateral tibia, vertically positioned into the sinus tarsi. Associate procedures were Achilles tendon lengthening (124), SERI procedure (61), hind-foot deformity correction (32). Postoperatively plaster-cast without weight-bearing for 4 weeks followed by walking boot was advised. All patients were reviewed at a minimum follow-up of 5 years.

Results: Before surgery the mean AOFAS score was 42+/−15, while it was 90+/−8 at follow-up (p< 0.005). Mean heel valgus deviation at rest was 15°+/−8° preoperatively and 6°+/−5° at follow-up (p< 0.005). Mean angulation of Meary’s line at talonavicular joint level was 160°+/−11° preoperatively and 174°+/−8 at follow-up. No complications were found. No or minimal arthritis progression was observed in the ipsilateral foot joints at follow up.

Conclusions: SAMBB resulted in an adequate correction of the deformity, with restoration of the anatomical shape of the hind foot and correction of the relationship with the midtarsal joint with no need of hardware. Consequent reduced arthritis progression and excellent clinical result were obtained.