Introduction Instrumented movement analysis at the time of return to sport after Anterior Cruciate Ligament (ACL) rupture allows the investigation of potential impairments. Among the biomechanical parameters associated with ACL injury risk, high knee adduction and low knee flexion angles have been widely investigated [1]. Some studies analyzed these angles at landing (initial contact, IC), whereas others considered the knee joint range of motion (RoM) within a short time window immediately after landing (risk time window: RTW) [2]. However, it is unclear if these two parameters provide comparable information and can be used indiscriminately. Thus, the aim of this study is to analyze the relationship between knee angles (both ab/adduction and flex/extension) obtained at IC and their RoM during RTW in patients with ACL reconstruction and in healthy controls during a single leg hop test. Methods Fifteen healthy (HC: 25.0±4.5 years, 72.9±6.2 kg, 1.79±0.6 m) and five soccer players with ACL reconstruction (ACLR: 28.0±9.0 years, 83.7±7.6 kg, 1.83±0.4 m) participated in this study. ACLRs were evaluated within a postoperative time window of 8-12 months. All participants had a Tegner Scale score >6. After a 5 min warm-up, 3 single leg hop tests were performed for each limb, landing on a force plate (AMTI, USA, 1000 Hz). The 3D trajectories of 52 markers were measured by an optoelectronic system (Vicon, UK, 200 Hz) [3]. Kinematics parameters related to ACL injury risk were extracted: knee adduction/abduction and flexion /extension angles at IC (KaddIC, KaddRoM) and their RoM during RTW (KflexIC, KflexRoM). RTW corresponded to the first 100 ms after foot landing (vertical ground reaction force >20 N) [4,5]. To investigate the relationship between knee angles at IC and RoMs, Pearson’s correlation coefficient was calculated for both the safe/dominant and injured/non-dominant limbs for all participants and each group (HC and ACLR) after checking for the normality of data distribution. Results Table 1 Knee adduction and flexion angles at IC and RoMs and Pearson’s correlation coefficients between them. Bold values indicate statistically significant results (p<.05). Discussions Knee joint angles at IC correlated with RoMs during the early phase of landing in the frontal plane (especially in the injured limb of ACLR), but not in the sagittal plane. This indicates that the higher the knee adduction at IC, the higher the RoM after landing, exposing the athlete to ALC injury risk. Conversely, the absence of a relationship between the knee flexion angle at IC and its RoM suggests that these two parameters do not necessarily provide the same information. Caution should be taken in their interpretation when detecting athletes at risk. It can be speculated that, in the tested population, knee flex/extensor muscles are able to better absorb the impact load with respect to the ab/adductor ones. Further research should include the analysis of muscle activity to address this hypothesis.
Anterior cruciate ligament injury risk parameters during landing: are knee angles at ground contact correlated with ranges of motion after landing?
L. Rum;
2023-01-01
Abstract
Introduction Instrumented movement analysis at the time of return to sport after Anterior Cruciate Ligament (ACL) rupture allows the investigation of potential impairments. Among the biomechanical parameters associated with ACL injury risk, high knee adduction and low knee flexion angles have been widely investigated [1]. Some studies analyzed these angles at landing (initial contact, IC), whereas others considered the knee joint range of motion (RoM) within a short time window immediately after landing (risk time window: RTW) [2]. However, it is unclear if these two parameters provide comparable information and can be used indiscriminately. Thus, the aim of this study is to analyze the relationship between knee angles (both ab/adduction and flex/extension) obtained at IC and their RoM during RTW in patients with ACL reconstruction and in healthy controls during a single leg hop test. Methods Fifteen healthy (HC: 25.0±4.5 years, 72.9±6.2 kg, 1.79±0.6 m) and five soccer players with ACL reconstruction (ACLR: 28.0±9.0 years, 83.7±7.6 kg, 1.83±0.4 m) participated in this study. ACLRs were evaluated within a postoperative time window of 8-12 months. All participants had a Tegner Scale score >6. After a 5 min warm-up, 3 single leg hop tests were performed for each limb, landing on a force plate (AMTI, USA, 1000 Hz). The 3D trajectories of 52 markers were measured by an optoelectronic system (Vicon, UK, 200 Hz) [3]. Kinematics parameters related to ACL injury risk were extracted: knee adduction/abduction and flexion /extension angles at IC (KaddIC, KaddRoM) and their RoM during RTW (KflexIC, KflexRoM). RTW corresponded to the first 100 ms after foot landing (vertical ground reaction force >20 N) [4,5]. To investigate the relationship between knee angles at IC and RoMs, Pearson’s correlation coefficient was calculated for both the safe/dominant and injured/non-dominant limbs for all participants and each group (HC and ACLR) after checking for the normality of data distribution. Results Table 1 Knee adduction and flexion angles at IC and RoMs and Pearson’s correlation coefficients between them. Bold values indicate statistically significant results (p<.05). Discussions Knee joint angles at IC correlated with RoMs during the early phase of landing in the frontal plane (especially in the injured limb of ACLR), but not in the sagittal plane. This indicates that the higher the knee adduction at IC, the higher the RoM after landing, exposing the athlete to ALC injury risk. Conversely, the absence of a relationship between the knee flexion angle at IC and its RoM suggests that these two parameters do not necessarily provide the same information. Caution should be taken in their interpretation when detecting athletes at risk. It can be speculated that, in the tested population, knee flex/extensor muscles are able to better absorb the impact load with respect to the ab/adductor ones. Further research should include the analysis of muscle activity to address this hypothesis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
