Computer-assisted orthopaedic surgery (CAOS) improves mechanical alignment and the accuracy of surgical cuts in the context of total knee arthroplasty. A simplified, CAOS enhanced instrumentation system was assessed to determine if the same effects could be achieved through the use of a less intrusive system. Two cohorts of surgeons (experienced and trainees) performed a series of total knee arthroplasty resections in knee models with and without navigation-enhanced instrumentation. The percentage of resections that deviated from the planned cut by more than 2°or 2mm (outliers) was determined by post-resection advanced imaging for six unique outcome metrics. Within each experience level, the use of the CAOS enhanced system significantly reduced the total percentage of outliers as compared to conventional instrumentation (Figure 1). The experienced users improved from 35% to 4% outliers overall (p < .001) and the trainees from 34% to 10% outliers (p < .001). Comparing across experience levels, the experienced surgeons performed significantly better in only a single resection metric with conventional instrumentation (Figure 2A), varus/valgus tibial alignment, with 8.3% outliers compared to the trainee's 63% outliers (p = .004). The use of CAOS enhanced instrumentation eliminated any differences between the two user groups for all measured resections (Figure 2B). Comparing CAOS enhanced to conventional instrumentation specifically between anatomical deformity types revealed that there is significant improvement (p < .05) with the use of enhanced instrumentation for all three deformity types (Figure 3). These results suggest that non-intrusive CAOS enhanced instrumentation is a viable alternative to conventional instrumentation with possible benefits. This trial also demonstrates that additional experience may not correlate to improved surgical accuracy, and outliers may be less a result of individual surgeon ability or specific anatomic deformities, and more so related to limitations of the instrumentation used or other yet unidentified factors.

Introduction and Aims: In order to evaluate the hypothesis that ‘Botulinum A Toxin (BoNT-A) improves function and health-related quality of life in patients and their caregivers’, the experience of a single institution that performed over 7500 injections in 515 patients was evaluated to provide safety data, injection guidelines, and current indications.

Method: This retrospective review utilised a computerised database that contains information from open-label trials (n=6), double-blind randomised trials (n=4), and cumulative treatment experience in 1100 children and adults with cerebral palsy. Standardised data collected over the past 15 years was analysed with respect to indications, complications, dosage, function, health-related quality of life of patients and their caregivers, rehabilitation (WeeFIM), gross motor function classification (GMFCS), and response rates. Pharmacoeconomic analysis was performed by linking with state Medicaid data.

Results: BoNT-A is safe and well tolerated. There were no systemic side effects in dosages ranging from four to 25 units per kilogram body weight. Standardised injection techniques included dilution from 10 to 100 units per cc with a maximum dose of six units per kilogram in a single muscle and 25 units per kilogram in a single patient. The maximum dose was 600 units.

Short-term response rates were 65–70%; intermediate response rates 45–50%. The most frequent complications were soreness of the injection site (15%) and transient weakness (2%). Ninety-five percent of injections were performed in the office without conscious sedation. Five percent were performed under general anaesthesia or with conscious sedation.

Based on these data, current indications include dynamic tone interfering with caregiver function (e.g., equinus gait), painful spasticity, post-operative spasticity, and pain management. Contraindications are failure to respond to previous injections. Pharmacoeconomic analysis diminished cost and improved function and quality of life of patients and/or caregivers.

Conclusion: Botulinum A Toxin is a safe and cost-effective drug in patients with cerebral palsy. Response rate is 50–70%. Optimal results are obtained with appropriate intramuscular localisation and sufficient volume to saturate neuromuscular junctions.