M Peiffer1, C Belvedere2, S Clockaerts3, T Leenders4, A Leardini2, E Audenaert5, J Victor5, A Burssens6. 1. Department of Orthopaedic Surgery, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium. Electronic address: Matthias.Peiffer@ugent.be. 2. Movement Analysis Laboratory and Functional-Clinical Evaluation of Prosthesis, IRCCS Istituto Ortopedico Rizzoli, via di Barbiano, 1/10, 40136 Bologna, Italy. 3. Department of Orthopaedic Surgery, AZ Groeninge, President Kennedylaan 4, 8500 Kortrijk, Belgium. 4. Department of Orthopaedic Surgery, AZ Monica, Florent Pauwelslei 21, 2100 Deurne, Belgium. 5. Department of Orthopaedic Surgery, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium. 6. Department of Orthopaedic Surgery, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium; University Orthopaedic Center, University of Utah, 590 Wakara Way Salt Lake City, UT 84108, USA.
Abstract
BACKGROUND: A medializing calcaneal osteotomy is frequently performed to correct adult-acquired flatfoot deformities, but there is lack of data on the associated three-dimensional variables defining the final correction. The aim of this study was to assess the correlation between the pre-operative hindfoot valgus deformity and calcaneal osteotomy angles and the post-operative calcaneal displacement. METHODS: Weight-bearing CT scans obtained pre- and post-operatively were retrospectively analyzed for sixteen patients. Corresponding three-dimensional bone models were used to measure valgus deformity pre- and post-operatively, inclination of the osteotomy and displacement of the calcaneus. Linear regression was conducted to assess the relationship between these measurements. RESULTS: On average, the hindfoot valgus changed from 13.1° (±4.6) pre-operatively to 5.7° (±4.3) post-operatively. A mean inferior displacement of 3.2mm (±1.3) was observed along the osteotomy with a mean inclination of 54.6° (±5.6), 80.5° (±10.7), -13.7° (±15.7) in the axial, sagittal and coronal planes, respectively. A statistically significant positive relationship (p<.05, R2=0.6) was found between the pre-operative valgus, the axial osteotomy inclination, and the inferior displacement. CONCLUSIONS: This study shows that the degree of pre-operative hindfoot valgus and the axial osteotomy angle are predictive factors for the amount of post-operative inferior displacement of the calcaneus. These findings demonstrate the added value of a computer-based pre-operative planning in clinical practice. Level of evidence II Prospective comparative study.
BACKGROUND: A medializing calcaneal osteotomy is frequently performed to correct adult-acquired flatfoot deformities, but there is lack of data on the associated three-dimensional variables defining the final correction. The aim of this study was to assess the correlation between the pre-operative hindfoot valgus deformity and calcaneal osteotomy angles and the post-operative calcaneal displacement. METHODS: Weight-bearing CT scans obtained pre- and post-operatively were retrospectively analyzed for sixteen patients. Corresponding three-dimensional bone models were used to measure valgus deformity pre- and post-operatively, inclination of the osteotomy and displacement of the calcaneus. Linear regression was conducted to assess the relationship between these measurements. RESULTS: On average, the hindfoot valgus changed from 13.1° (±4.6) pre-operatively to 5.7° (±4.3) post-operatively. A mean inferior displacement of 3.2mm (±1.3) was observed along the osteotomy with a mean inclination of 54.6° (±5.6), 80.5° (±10.7), -13.7° (±15.7) in the axial, sagittal and coronal planes, respectively. A statistically significant positive relationship (p<.05, R2=0.6) was found between the pre-operative valgus, the axial osteotomy inclination, and the inferior displacement. CONCLUSIONS: This study shows that the degree of pre-operative hindfoot valgus and the axial osteotomy angle are predictive factors for the amount of post-operative inferior displacement of the calcaneus. These findings demonstrate the added value of a computer-based pre-operative planning in clinical practice. Level of evidence II Prospective comparative study.