Abstract
Aim: To improve our technique of subtalar fusion for the correction of flexible abducto-valgus foot deformities during single event multilevel surgery in children with cerebral palsy, specifically, to decrease operating time, avoid donor site morbidity, improve fusion rates and prevent loss of correction.
Methods and Results: The modifications are:
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Preparation of the sinus tarsi using hemispherical reamers.
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Grafting the sinus with a press fit, cortico-cancellous iliac crest allograft, cut with a circular “cookie cutter”.
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Placing an 8mm titanium cannulated screw parallel to the talo-navicular and calcaneo-cuboid joints.
All patients had a preoperative instrumented gait analysis, video recordings of foot position, AP and lateral weight bearing radiographs.
Patients were encouraged to weight bear as tolerated in a cast at three weeks. Six weeks postoperatively the casts were replaced with ankle-foot orthoses. Gait laboratory reviews were conducted at 3, 6, 9, 12 and 24 months postoperatively with radiological evaluation of the subtalar fusion at 6, 12 and 24 months postoperatively.
Between January 2001 and December 2004, 58 children, mean age 9 years and 4 months underwent bilateral subtalar fusions with the modified technique during multilevel surgery. Fifty-eight patients were reviewed 12 months postoperatively and 54 at 24 months postoperatively.
Deformity correction was uniformly satisfactory. All patients had complete graft incorporation on plane radiographs. No patient required a revision procedure. Six patients subsequently had first metatarso-phalangeal joint fusions for symptomatic hallux valgus.
Conclusion: The reliability of extra-articular fusion of the subtalar joint improved dramatically using screw fixation and iliac crest graft as described by Dennyson and Fulford. This can be further improved by the use of hemispherical reamers to the sinus tarsi and cannulated screws for fixation of the talus to the os calcis. Allograft is a reliable substitute for autograft and is acceptable to most patients and families.
Correspondence should be addressed to: Mr J. B. Hunter, BSCOS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
