Time to Stabilization of Anterior Cruciate Ligament–Reconstructed Versus Healthy Knees in National Collegiate Athletic Association Division I Female Athletes

Abstract

Jump landing is a common activity in collegiate activities, such as women's basketball, volleyball, and soccer, and is a common mechanism for anterior cruciate ligament (ACL) injury. It is important to better understand how athletes returning to competition after ACL reconstruction are able to maintain dynamic postural control during a jump landing. To use time to stabilization (TTS) to measure differences in dynamic postural control during jump landing in ACL-reconstructed (ACLR) knees compared with healthy knees among National Collegiate Athletic Association Division I female athletes. Case-control study. University athletic training research laboratory. Twenty-four Division I female basketball, volleyball, and soccer players volunteered and were assigned to the healthy control group (n = 12) or the ACLR knee group (n = 12). Participants with ACLR knees were matched to participants with healthy knees by sport and by similar age, height, and mass. At 1 session, participants performed a single-leg landing task for both limbs. They were instructed to stabilize as quickly as possible in a single-limb stance and remain as motionless as possible for 10 seconds. The anterior-posterior TTS and medial-lateral TTS ground reaction force data were used to calculate resultant vector of the TTS (RVTTS) during a jump landing. A 1-way analysis of variance was used to determine group differences on RVTTS. The means and SDs from the participants' 10 trials in each leg were used for the analyses. The ACLR group (2.01 ± 0.15 seconds, 95% confidence interval [CI] = 1.91, 2.10) took longer to stabilize than the control group (1.90 ± 0.07 seconds, 95% CI = 1.86, 1.95) (F(1,22) = 4.28, P = .05). This result was associated with a large effect size and a 95% CI that did not cross zero (Cohen d = 1.0, 95% CI = 0.91, 1.09). Although they were Division I female athletes at an average of 2.5 years after ACL reconstruction, participants with ACLR knees demonstrated dynamic postural-control deficits as evidenced by their difficulty in controlling ground reaction forces. This increased TTS measurement might contribute to the established literature reflecting differences in single-limb dynamic control. Clinicians might need to focus rehabilitation efforts on stabilization after jump landing. Further research is needed to determine if TTS is a contributing factor in future injury.