Sven Putnis1, Thomas Neri2, Antonio Klasan2, Myles Coolican2. 1. Sydney Orthopaedic Research Institute, Level 1 The Gallery, 445 Victoria Avenue, Chatswood, NSW, 2067, Australia. svenputnis@gmail.com. 2. Sydney Orthopaedic Research Institute, Level 1 The Gallery, 445 Victoria Avenue, Chatswood, NSW, 2067, Australia.
Abstract
BACKGROUND: Our objective was to assess clinical and radiological findings following a medial opening wedge high tibial osteotomy using a biphasic calcium phosphate (BCP) synthetic bone substitute, designed as a wedge with two differing zones of density. The in-vivo behaviour of this type of bone substitute over time is currently unknown. HYPOTHESIS: Our hypothesis was that BCP synthetic bone would facilitate bone union and undergo replacement with host bone over the study period. PATIENTS AND METHODS: Fifteen sequential patients were followed prospectively for minimum 4-years post-operatively. All patients were evaluated clinically using patient reported outcome measures and radiologically to evaluate alignment with maintenance of the osteotomy correction, and bone union with expected BCP dissolution. RESULTS: All patients had good clinical scores with no reported complications at 4 years. In all cases there were radiographic findings of bone union with consolidation and no loss of correction. However the graft remained densely radiopaque at final follow-up. DISCUSSIONS: This study demonstrates that a BCP graft in combination with a locking plate for a medial opening wedge HTO allows early weight-bearing, maintains correction and provides good clinical outcomes. Whilst higher densities of BCP are strong, they do not resorb fully, remaining radiographically visible. This may have implications for the performance of a future knee arthroplasty and caution should therefore be taken.
BACKGROUND: Our objective was to assess clinical and radiological findings following a medial opening wedge high tibial osteotomy using a biphasic calcium phosphate (BCP) synthetic bone substitute, designed as a wedge with two differing zones of density. The in-vivo behaviour of this type of bone substitute over time is currently unknown. HYPOTHESIS: Our hypothesis was that BCP synthetic bone would facilitate bone union and undergo replacement with host bone over the study period. PATIENTS AND METHODS: Fifteen sequential patients were followed prospectively for minimum 4-years post-operatively. All patients were evaluated clinically using patient reported outcome measures and radiologically to evaluate alignment with maintenance of the osteotomy correction, and bone union with expected BCP dissolution. RESULTS: All patients had good clinical scores with no reported complications at 4 years. In all cases there were radiographic findings of bone union with consolidation and no loss of correction. However the graft remained densely radiopaque at final follow-up. DISCUSSIONS: This study demonstrates that a BCP graft in combination with a locking plate for a medial opening wedge HTO allows early weight-bearing, maintains correction and provides good clinical outcomes. Whilst higher densities of BCP are strong, they do not resorb fully, remaining radiographically visible. This may have implications for the performance of a future knee arthroplasty and caution should therefore be taken.