2015 ISAKOS Biennial Congress ePoster #1323
Are There Limb-To-Limb Differences in Knee and Hip Kinematics Between Collision, Contact, and Non-Contact Sport Athletes One Year After ACLR?
Amelia J. H. Arundale, PT, DPT, SCS, Newark, DE UNITED STATES
Lynn Snyder-Mackler, PT, ScD, FAPTA, Newark, DE UNITED STATES
University of Delaware, Newark, Delaware, USA
FDA Status Not Applicable
Summary: Limited contact sport athletes have greater limb-to-limb differences in hip abduction angle at initial contact, but athletes of all sports have hip and knee flexion moment limb-to-limb differences larger than the MCID.
Anterior cruciate ligament (ACL) injuries are common in cutting/pivoting sports. Collision sports, American football in particular, have a high risk of ACL injury, subsequent ACL injury, and higher rates of early onset-osteoarthritis. The rate of return to sport in football is similar to that of other sports, however return to sport in itself is a risk factor for secondary ACL injury. Research has indicated that asymmetries still exist at one and two years after ACL reconstruction (ACLR), however no one has examined if there are particular differences between athletes in different sports. Thus, the purpose of this study was to examine limb-to-limb differences in collision (COL), contact (CON), and non-contact (NCON) sport athletes who have returned to their prior level of activity at one year after ACL reconstruction.
35 athletes (25 male, 10 female) who had returned to their prior level of activity were tested one year after ACLR. Subjects were classified as COL, CON, LCON, and NCON, based on their sport of injury. Motion analysis was performed examining hip and knee angles and moments in the sagittal and frontal planes at initial contact. Limb-to-limb differences were calculated by subtracting the involved limb angle or moment from the uninvolved limb. A MANOVA with pairwise comparisons was used to assess differences between groups in kinematic variables. Group means in the sagittal plane were also compared to the minimal clinically important difference for knee and hip angle (knee and hip =3°) and moment (knee =0.04 Nm/Kgm, hip =0.06Nm/kgm). Significance was set a priori p=0.05.
Significant differences were found in hip abduction angle (p=0.03), with the LCON group (mean 6.75±1.15) having significantly greater limb-to-limb difference than the CON (mean 2.55±0.67, p=0.004) and the NCON (mean 2.63±1.62, p=0.05). The COL and LCON groups had hip (mean COL =4.17±0.99, LCON =3.87±1.14) and knee flexion (mean COL =3.87±1.02, LCON =4.70±1.19) angle limb-to-limb differences larger than the minimal clinically important differences. All groups had hip (mean COL=0.166±0.09, CON =0.26±0.06, LCON =0.17±0.11, NCON =0.27±0.15) and knee (mean COL =0.06±0.03, CON =0.10±0.03, LCON =0.12± 0.03, NCON =0.12±0.04) moment limb-to-limb differences larger than the minimal clinically important differences.
Discussion:Although all of the athletes had returned to their pre-injury level of activity all groups had sagittal plane knee and hip moment limb-to-limb differences larger that the previously published MCIDs. Further, the COL and LCON groups had sagittal plane hip and knee flexion angle limb-to-limb difference larger than the MCID. While it is unclear why the LCON group had significantly larger limb-to-limb differences in hip abduction angle, any limb asymmetry may place an athlete at increased risk for secondary ACL injury (ipsi-/contralateral side).
These findings indicate that limb-to-limb gait differences exist in athletes of all sports at one year after ACLR, and that sport categorization may not be appropriate for identifying athletes with larger limb-to-limb differences.