Hayden Dennis, Alyssa Evans-Pickett, Garritt Page, Brian G Pietrosimone, J Troy Blackburn, Matthew K Seeley
Continuous vGRF and KFA were able to cluster patients post-ACLR into distinct groups that exhibited differing symptom status and biomechanics. These results offer new insight regarding relationships between walking biomechanics and post-ACLR symptoms and can guide future research designed to manipulate walking biomechanics to improve post-ACLR outcomes.
CONTEXT: Relationships between continuous measures of walking biomechanics and post anterior cruciate ligament reconstruction (ACLR) outcomes are unclear. The purposes of this study were to: (1) determine whether continuous measures of walking vertical ground reaction force (vGRF) and knee-flexion angle (KFA) can be used to cluster patients post-ACLR and (2) compare symptom status and discrete measures of walking biomechanics between resulting clusters.
DESIGN: Cross-sectional.
METHODS: A Bayesian hierarchical model was used to cluster 196 patients post-ACLR (118 females; age = 21 ± 4 y; height = 1.71 ± 0.10 cm; mass = 73 ± 15 kg; time post-ACLR = 25 ± 26 mo) on involved-leg vGRF and KFA waveforms during walking. Symptom status (asymptomatic or symptomatic) was derived from Knee injury and Osteoarthritis Outcome Scores. Symptom status and discrete walking vGRF and KFA characteristics were compared between resulting patient clusters.
RESULTS: Five distinct patient clusters resulted and exhibited different representative vGRF and KFA waveforms. Clusters 1 to 4 consisted of mostly asymptomatic patients (63%, n = 47; 53%, n = 49; 58%, n = 24; 74%, n = 31) and were combined to form an aggregate group. Cluster 5 consisted of mostly symptomatic patients (58%; n = 45). The aggregate group exhibited 5% greater impact peak vGRF, 42% greater excursion between impact peak and midstance vGRF minimum, greater average (18%) and instantaneous (15%) vGRF rates during early stance, and 62% greater KFA excursion between peak KFA in early stance and subsequent peak knee extension than Cluster 5.
CONCLUSION: Continuous vGRF and KFA were able to cluster patients post-ACLR into distinct groups that exhibited differing symptom status and biomechanics. These results offer new insight regarding relationships between walking biomechanics and post-ACLR symptoms and can guide future research designed to manipulate walking biomechanics to improve post-ACLR outcomes.