MINIMALLY INVASIVE AND OPEN POSTERIOR CALCANEAL DISPLACEMENT OSTEOTOMY IN PAEDIATRIC HINDFOOT DEFORMITY CORRECTION: COMPARISON OF CLINICAL, RADIOLOGICAL, AND PATIENT-REPORTED OUTCOMES

The posterior calcaneal displacement osteotomy (PDCO) is a surgical procedure to correct hindfoot valgus or varus deformities by translating the calcaneal tuberosity medially or laterally, respectively. Traditionally PDCO is performed through an open lateral approach. Minimally invasive techniques are evolving and becoming more popular with reported decreases in wound complications, nerve injuries, and swelling in adult patients. The aim of this study is to report clinical and patient reported outcomes comparing PDCO through an open (O-PDCO) versus a minimally invasive approach (MI-PDCO). A consecutive series of PCDO performed by a single paediatric foot and ankle surgeon was reviewed. All calcaneal osteotomies were part of a complex foot and ankle reconstructive procedure including clubfoot, flatfoot, cavovarus and neurological deformities. Radiographic and clinical outcome data including neurovascular injury and wound complications was collected. The O-PDCO was performed through an oblique incision over the lateral calcaneal tuberosity and performed with an oscillating saw and osteotomes. The percutaneous osteotomy for the MI-PDCO was done through a 5mm incision and using a narrow, low-speed, high torque, cortical self-irrigating burr under fluoroscopic guidance. Bony fixation was achieved with K-wires or screws. (Figure 1) Post-operatively, patients were immobilized in a non-weight bearing cast for 6 weeks. Twenty-nine calcaneal osteotomies in 23 patients aged 8 to 18 years (mean 12.9) were included. Pre-operative deformities included 11 hindfoot varus for clubfoot, 9 flatfoot, 7 cavovarus and 2 hindfoot valgus for overcorrected clubfoot. Eleven osteotomies were performed open (O-PDCO) and 18 minimally invasive (MI-PDCO). Mean overall follow-up time was 17.9 months (range 4.6–35.5). Mean displacement of the calcaneal tuberosity was 8.6mm (range 7.4–13.0) in the O-PDCO group and 7.3mm (range 5.5–10.0) in the MI-PDCO group based on intra-operative Harris views, respectively. No delayed union, non-union, or growth disturbance was observed. There were 2 minor wound healing issues in the O-PDCO (18.1%) and none in the MI-PDCO (0%) group. Six feet had nerve paresthesias: two (1 sural and 1 tibial nerve) were in the O-PDCO (18.1%) and four sural nerve irritations were in the MI-PDCO (22.2%) group. All of them improved or resolved during follow-up. No vascular injuries occured, and no revision surgeries were required in either group. The Child version Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) resulted in improved scores in all 3 domains in both groups, especially in the domains school/play there was an increase of 0.25 in the O-PDCO and 0.15 in the MI-PDCO group. Minimally invasive posterior calcaneal displacement osteotomy is a safe technique to correct paediatric hindfoot deformities. Deformity correction power was effective in O-PDCO and MI-PDCO. There were fewer wound healing complications in the minimally invasive group, but temporary post-operative paresthesias are common in both techniques. This is the first clinical data on the use of minimally invasive calcaneal osteotomy in a paediatric patient population for complex deformity corrections. MI-PDCO could become the gold standard procedure in paediatric hindfoot reconstructions. It has great potential in complex deformity corrections with multiple concurrent osteotomies to reduce wound complications. For any figures or tables, please contact the authors directly.