ACL reconstruction

Effects of an 8-week cadence gait training program on knee loading in individuals following ACL reconstruction

While normalization of gait is a primary goal of early rehabilitation, between limb asymmetries in knee extensor moment can persist 6-24 months later and previous literature assessing gait interventions is limited. The purpose of this study was to assess the influence of subject-specific cadence gait training program on knee loading mechanics following ACLr. Nine individuals completed an 8-week cadence training program (20min, 3x/week; Table1) and nine sex- and surgery-matched individuals served as controls. All eighteen participants received standard physical therapy and were tested at 1 and 3 months post-op. Kinematic and kinetic data were collected during walking at a self-selected speed. Repeated measures ANOVAs were used for comparisons; significance α≤0.05. Main effects of limb and time were observed: knee ROM (kROM;p<0.001;p=0.044;Fig.1) and knee extensor moment (kEXT;p=0.003;p=0.002) in the cadence and control groups, respectively. No main effects of group for kROM (p=0.136) or kEXT (p=0.229) were found. A trend toward a significant group x time x limb interaction was observed in kEXT (p=0.092), but not kROM (p=0.412). Post-hoc analyses of kEXT (Fig.2) revealed a significant time x limb interaction for the cadence group (p=0.053) but not the control group (p=0.884). In the cadence group, the time x limb interaction was driven by a 131% increase in kEXT in the surgical limb versus a 42% increase in the non-surgical limb between T1 and T2. Consistent with previous findings, these pilot data show promising results as the cadence intervention resulted in improvements in sagittal plane knee loading compared to controls.

Listed In: Biomechanics, Gait, Orthopedic Research, Physical Therapy, Sports Science

Movement and Loading Symmetry Changes when Wearing a Functional Knee Brace Following ACL Reconstruction

Asymmetries in discrete measures following anterior cruciate ligament reconstruction (ACL-R) during landing have been reported to be risk factors for secondary ACL injuries. Our purpose was to examine the impact of functional brace wear on kinematic and kinetic inter-limb movement symmetry during landing in ACL-R patients. 20 adolescent athletes (15.8 ± 1.2 years) (7 male, 13 female) 6 months following ACL reconstruction performed 5 trials of a stop-jump task in both a braced (B) and non-braced (NB) condition, with the first landing being analyzed. A custom fit functional knee brace (DJO, Vista, CA) was worn on the ACL reconstructed limb (AL) during the B trials. Mean curves were created for each limb (AL and unaffected limb (UL)) for the vertical (vGRF) and anterior-posterior ground reaction forces (apGRF) and frontal and sagittal knee angles and moments. Coefficients of multiple determination (CMD) between the AL and UL curves were compared between B and NB conditions with students’ t-tests (p≤0.05). No significant differences existed for movement and loading symmetry between B and NB conditions among all subjects. Secondary analysis revealed significant differences in apGRF (p=0.014), vGRF (p=0.011) and sagittal knee angles (p=0.003) in subjects with improved sagittal knee angle symmetry in the B condition. The data show that brace wear improves loading symmetry in adolescent patients that also exhibit improved sagittal knee angle symmetry while braced 6 months following ACL-R. Identifying factors that affect inter-limb movement and loading response to brace wear could assist in determining each patient’s need for a brace.

Listed In: Biomechanics, Sports Science

Biochemical markers of type II collagen degradation and synthesis are not associated with biomechanical variables in patients following ACL reconstruction.

This study investigated the association of serum C-propeptide (sCPII), urinary CTX-II (uCTX-II), and uCTX-II:sCPII with peak vertical ground reaction force (PVGRF) and quadriceps strength during jump-landing in patients with ACL reconstruction (ACLR). METHODS: twenty two patients with ACLR (Male=14, age=19.6 ± 4 yr) were tested 20 weeks after the surgery. Blood and urine samples were collected. sCPII and uCTX-II, biomarkers of articular degradation and synthesis respectively, were analyze using commercial ELISAs. Subjects performed 3 trials of a forward drop land and a drop vertical jump. Subjects started on a 20 cm step and landed on a force platform (AMTI). PVGRF was analyzed on the surgical side. Quadriceps strength (PKET) was assessed with an isokinetic dynamometer (60°/s). PVGRF and PKET were normalized to body weight (BW). Pearson’s correlation, with and without adjustment for age, was used to analyze associations among variables. RESULTS: Mean (± SD) log concentrations were 2.88 ± 0.19 and 3.32 ± 0.49 ng/mmol for sCPII and uCTX-II respectively; and for uCTXII:CPII was 1.16 ± 0.18. PVGRF was 3.2 BW ± 0.3 and 1.4 BW ± 0.3 for the forward drop land and drop vertical jump tasks, respectively; PKET was 0.92 BW ± 0.2. There were no significant correlations among variables (p≥0.2), except for a trend towards a positive correlation between PKET and uCTXII:sCPII (r = 406, p = .076). CONCLUSSIONS: Biomarkers of type II collagen metabolism were not associated with jump-landing forces. However, higher quadriceps strength may be associated with a shift in articular cartilage metabolism towards degradation.

Listed In: Biomechanics, Orthopedic Research, Physical Therapy, Sports Science