Abstract
Introduction
Computer hexapod assisted orthopaedic surgery (CHAOS) has previously been shown to provide a predictable and safe method for correcting multiplanar femoral deformity. We report the outcomes of tibial deformity correction using CHAOS, as well as a new cohort of femoral CHAOS procedures.
Materials and Methods
Retrospective review of medical records and radiographs for patients who underwent CHAOS for lower limb deformity at our tertiary centre between 2012–2020.
Results
There were 70 consecutive cases from 56 patients with no loss to follow-up. Mean age was 40 years (17 to 77); 59% male. There were 48 femoral and 22 tibial procedures. Method of fixation was intramedullary nailing in 47 cases and locking plates in 23.
Multiplanar correction was required in 43 cases. The largest correction of rotation was 40 degrees, and angulation was 28 degrees. Mean mechanical axis deviation reduction per procedure was 17.2 mm, maximum 89 mm. Deformity correction was mechanically satisfactory in all patients bar one who was under-corrected, requiring revision.
Complications from femoral surgery included one under-correction, two cases of non-union, and one pulmonary embolism. Complications from tibial surgery were one locking plate fatigue failure, one compartment syndrome, one pseudoaneurysm of the anterior tibial artery requiring stenting, and one transient neurapraxia of the common peroneal nerve. There were no deaths.
Conclusions
CHAOS can be used for reliable correction of complex deformities of both the femur and tibia. The risk profile appears to differ between femoral and tibial surgeries.
