A 5 year prospective study
C. Kinast, P. Bouliopoulos, J. Hamel

  • Introduction / Background: Scarf osteotomy of the first metatarsal in combination with Akin-osteotomy of the proximal phalanx of the big toe is a well known and accepted technique for the correction of hallux valgus deformity. So is the performance of an arthrodesis of the proximal interphalangeal joint of the lesser toes in case of hammer-toe deformity. Usually the fixation is done by metallic implants (screws or K-wires).
  • Aim / Purpose: In this prospective study exclusively bioabsorbable implants LactoSorb® (co-polymer of poly-lactic-acid and poly-glycolic-acid) were used for the internal fixation of scarf osteotomy, Akin osteotomy and PIP-arthrodesis. The aim was to observe these patients for any side effects or fixation failure.
  • Methods: We studied prospectively 59 feet in which scarf-osteotomy was performed. In 53 cases an Akin osteotomy was performed in addition. In all cases we performed a lateral release and medial tightening of the MP-I capsule, as well as a tenotomy of the adductor hallucis tendon. For the fixation of these osteotomies we used 2,5 mm bioabsorbable screws. In 35 hammertoes of these feet we performed a PIP-arthrodesis, which was fixated with a bioabsorbable 2,0 mm pin. Clinical and radiological examination was done preoperatively and postoperatively at 1st day, 2nd, 6th and 12th week, 6th and 12th month and after 5 years.
  • Results: The AOFAS forefoot score improved from 52 preoperatively to 92 points 5 years after surgery. The intermetatarsal angle improved from 14° to 7° and the hallux valgus angle from 28° to 8°. A fusion of the PIP joint occurred in 72% of the cases. No allergic reactions to the bioabsorbable implants were observed, neither failure of fixation. One heavy male patient showed proximal diaphyseal fracture without failure of bioabsorbable implant fixation. 5 years after operation the screw holes are not visible on the X-rays of the feet. 96% of the patients were subjectively overall satisfied and would have this kind of operation again.
  • Discussion / Conclusion: Bioabsorbable implants LactoSorb® are in forefoot surgery a good and secure alternative to the usually used metallic implants. There is no need of a second operation for the removal of these implants. Patients like their X-rays better, because bioabsorbable implants are not visible.