Sparta Science Force Plate Assessment of Recovery Following Anterior Cruciate Ligament Reconstruction

Objectives: The Sparta Science force plate is a recent technology which provides kinetic information derived from movements such as vertical jump and balance tests. Until now this has been utilised to assess fitness amongst athletic and military populations. The outputs from this system may be useful in the assessment of return to sport (RTS) readiness following anterior cruciate ligament (ACL) reconstruction. The aim of this study was to determine the reliability of the Sparta Science metrics in ACL reconstruction patients and to compare these results with the healthy population norms provided by the machine learning platform. Methods: Patients undergoing primary ACL reconstruction were recruited prospectively to undergo biomechanical testing at 9 months postoperatively. Exclusions included previous significant knee injuries and multiligament injuries requiring surgery. Testing included knee laxity assessment, hop tests, isokinetic strength testing, and kinetic measures using the Sparta Science force plate. The force plate tests included double and single leg vertical jump tests and balance tasks. Each test was repeated after a 5-minute rest period. Metrics such as jump height, and the Sparta derived kinetic profiles including load, explode and drive were recorded and analysed. These metrics represent the ability to create, transfer and apply force efficiently during the jump. Intra-class correlation coefficients (ICCs) were calculated to determine relative reliability and the smallest detectable change (SDC) was reported for each variable. Results: A total of 74 patients were recruited, 44 (60%) males and the mean age was 25 (±9) years. Hamstring autograft was used in 55 (74%) patients and quadriceps tendon in 19 (26%). The mean pre-injury Marx scale was 13.1 (±3.4) with 54% of participants playing high-level competitive sport. The mean follow-up time to testing was 9.9 (±1.7) months postoperatively. The Sparta Science derived metrics showed moderate to excellent reliability for double leg (ICC 0.75-0.97) and single leg vertical jumps (ICC 0.81-0.95), as well as balance assessments (ICC 0.71-0.81). The ACL reconstruction cohort exhibited lower kinetic t-scores compared to the healthy population for double and single leg vertical jump tests. Conversely, t-scores were greater than the population mean for the balance tests. Jump height and explode scores were significantly lower for operated knees compared to the uninjured side (p<0.001) in the single leg jump test, while no difference was observed for load and drive scores. In both jump tasks, jump height, explode and drive scores were found to correlate with performance in hop tests and quadriceps and hamstring strength. Conclusion: The Sparta Science force plate platform is reliable when used to assess patients recovering from ACL reconstruction with ICCs showing moderate to excellent reliability for test-retest repeatability at the same timepoint. We identified kinetic deficiencies in the vertical jump test performance of patients following ACL reconstruction, and also showed that these results correlate with other traditional methods of assessment for RTS testing. The results demonstrate the Sparta system's potential as a reliable, accessible and cost-effective alternative to traditional testing methods. Identifying and addressing kinetic deficiencies before RTS could reduce the risk of future injury following ACL reconstruction.