Biomechanical Threshold Values for Identifying Clinically Significant Knee-Related Symptoms Six Months Following Anterior Cruciate Ligament Reconstruction.

CONTEXT: Slower habitual walking speed and aberrant gait biomechanics are linked to clinically significant knee-related symptoms and articular cartilage composition changes linked to posttraumatic osteoarthritis (PTOA) following anterior cruciate ligament reconstruction (ACLR). OBJECTIVE: To determine specific gait biomechanical variables that can accurately identify individuals with clinically significant knee-related symptoms post-ACLR, and the corresponding threshold values, sensitivity, specificity, and odds ratios for each biomechanical variable. DESIGN: Cross-sectional analysis. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Seventy-one individuals (n=38 female; age=21±4 years; height=1.76±0.11 m; mass=75.38±13.79 kg) who were 6 months post-primary unilateral ACLR (6.2±0.4 months). MAIN OUTCOME MEASURES: 3D motion capture of 5 overground walking trials was used to calculate discrete gait biomechanical variables of interest during stance phase (1st and 2nd peak vertical ground reaction force [vGRF]; midstance minimum vGRF; peak internal knee abduction and extension moments; and peak knee flexion angle), along with habitual walking speed. Knee Injury and Osteoarthritis Outcome Scores (KOOS) was used to dichotomize patients as symptomatic (n=51) or asymptomatic (n=20) using the Englund et al. 2003 KOOS guidelines for defining clinically significant knee-related symptoms. Separate receiver operating characteristic (ROC) curves and respective areas under the curve (AUC) were used to evaluate the capability of each biomechanical variable of interest for identifying individuals with clinically significant knee-related symptoms. RESULTS: Habitual walking speed (AUC=0.66), vGRF at midstance (AUC=0.69), and 2nd peak vGRF (AUC=0.76), demonstrated low-to-moderate accuracy for identifying individuals with clinically significant knee-related symptoms. Individuals who exhibited habitual walking speeds ≤1.27 m/s, midstance vGRF ≥0.82 BW, and 2nd peak vGRF ≤1.11 BW, demonstrated 3.13, 6.36, and 9.57 times higher odds of experiencing clinically significant knee-related symptoms, respectively. CONCLUSIONS: Critical thresholds for gait variables may be utilized to identify individuals with increased odds of clinically significant knee-related symptoms and potential targets for future interventions.

Age-, Sex-, and Graft-Specific Reference Values From 783 Adolescent Patients at 5 to 7 Months After ACL Reconstruction: IKDC, Pedi-IKDC, KOOS, ACL-RSI, Single-Leg Hop, and Thigh Strength.

OBJECTIVE: To describe age-, sex-, and graft source-specific reference values for patient-reported, physical function, and strength outcome measures in adolescents at 5 to 7 months after anterior cruciate ligament reconstruction. DESIGN: Cross-sectional study. METHODS: Data were collected at 3 universities and 2 children's hospitals. The participants completed at least one of the International Knee Documentation Committee (IKDC) Subjective Evaluation Form, Pediatric IKDC (Pedi-IKDC), Knee Injury and Osteoarthritis Outcomes Score (KOOS), and Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) Scale. Participants also completed single-leg hop tests and/or isokinetic quadriceps and hamstrings strength assessments (at 60°/s). Reference values were summarized using descriptive statistics and stratified for age, sex, and graft source. RESULTS: Reference values were reported for common patient-reported outcomes and measures of physical function and strength from 783 participants (56% females, age = 16. 4 ± 2.0 years) who were in early adolescence (12-14 years, N = 183, 52% females), middle adolescence (15-17 years, N = 456, 58% females), or late adolescence (18-20 years, N = 144, 55% females). Three hundred seventy-nine participants (48.4%) received a bone-patellar tendon-bone autograft, 292 participants (37.3%) received hamstring tendon autograft, and 112 participants (14.3%) received autograft or allograft from an alternative source. CONCLUSION: Reference values for common patient-reported outcomes and measures of physical function and strength differed depending on a patient's age, sex, and graft source. Using patient-specific reference values, in addition to previously described age-appropriate cutoff values, may help clinicians monitor and progress patients through rehabilitation and return to physical activity after anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther 2023;53(4):1-8. Epub: 23 January 2023. doi:10.2519/jospt.2023.11389.

A Comparison of Psychological Readiness and Patient-Reported Function Between Sexes After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Postoperative functional and return-to-sport outcomes after anterior cruciate ligament reconstruction (ACLR) differ by sex. However, whether sex disparities are observed in patient-reported outcome measures (PROMs) before return to sport after ACLR is unclear. OBJECTIVES: To compare common PROMs between young men and women who had not yet returned to sport after ACLR. DESIGN: Cross-sectional study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-five young men (age = 18.7 ± 2.7 years, time since surgery = 6.8 ± 1.4 months) and 45 women matched for age (±1 year) and time since surgery (±1 month; age = 18.8 ± 2.8 years, time since surgery = 6.9 ± 1.4 months) with ACLR participated. MAIN OUTCOME MEASURE(S): Participants completed the Tegner Activity Scale, ACL Return to Sport After Injury scale, Tampa Scale of Kinesiophobia, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Score, and Knee Injury and Osteoarthritis Outcome Score (KOOS). The PROMs were compared between men and women using Mann-Whitney U tests. Odds ratios were calculated to evaluate the odds of a male reporting a PROM value above the previously established normative value as compared with a female. RESULTS: Sex differences were present for the IKDC score (P = .01) and KOOS Pain score (P = .04) but not for the Tegner Activity Scale (P = .22), ACL Return to Sport After Injury scale score (P = .78), Tampa Scale of Kinesiophobia score (P = .64), or other KOOS subscales (P values = .40 to .52). The odds of reporting values above normative levels differed only for the IKDC score (odds ratio = 2.72, 95% confidence interval = 1.16, 6.38). CONCLUSIONS: After ACLR, young men and women reported similar levels of knee-related function, fear of movement, and readiness for return to sport and were equally likely to meet clinically meaningful normative values before return to sport. Overreliance on patient reports or objective functional outcomes in evaluating patient progress and readiness for return to sport after ACLR may limit clinicians in their ability to comprehensively evaluate and develop individualized interventional approaches that optimize patient outcomes.

Assessment of Free-Living Cadence Using ActiGraph Accelerometers Between Individuals With and Without Anterior Cruciate Ligament Reconstruction.

CONTEXT: Anterior cruciate ligament reconstruction (ACLR) and gait speed are risk factors for developing knee osteoarthritis (OA). Measuring minute-level cadence during free-living activities may aid in identifying individuals at elevated risk of developing slow habitual gait speed and, in the long term, OA. OBJECTIVE: To assess differences in peak 1-minute cadence and weekly time in different cadence intensities between individuals with and without ACLR. DESIGN: Cross-sectional study. SETTING: Short-term, free-living conditions. PATIENTS OR OTHER PARTICIPANTS: A total of 57 participants with ACLR (34 women, 23 men; age = 20.9 ± 3.2 years, time since surgery = 28.7 ± 17.7 months) and 42 healthy control participants (22 women, 20 men; age = 20.7 ± 1.7 years). MAIN OUTCOME MEASURE(S): Each participant wore a physical activity monitor for 7 days. Data were collected at 30 Hz, processed in 60-second epochs, and included in the analyses if the activity monitor was worn for at least 10 hours per day over 4 days. Mean daily steps, peak 1-minute cadence, and weekly minutes spent at 60 to 79 (slow walking), 80 to 99 (medium walking), 100 to 119 (brisk walking), ≥100 (moderate- to vigorous-intensity ambulation), and ≥130 (vigorous-intensity ambulation) steps per minute were calculated. One-way analyses of covariance were conducted to determine differences between groups, controlling for height and activity-monitor wear time. RESULTS: Those with ACLR took fewer daily steps (8422 ± 2663 versus 10 033 ± 3046 steps; P = .005) and spent fewer weekly minutes in moderate- to vigorous-intensity cadence (175.8 ± 116.5 minutes versus 218.5 ± 137.1 minutes; P = .048) than participants without ACLR. We observed no differences in minutes spent at slow (ACLR = 77.4 ± 40.5 minutes versus control = 83.9 ± 34.3 minutes; P = .88), medium (ACLR = 71.6 ± 40.2 minutes versus control = 82.9 ± 46.8 minutes; P = .56), brisk (ACLR = 115.3 ± 70.3 minutes versus control = 138.3 ± 73.3 minutes; P = .18), or vigorous-intensity (ACLR = 24.3 ± 36.5 minutes versus control = 38.1 ± 60.9 minutes; P = .10) cadences per week. CONCLUSIONS: Participants with ACLR walked approximately 40 fewer minutes per week in moderate- to vigorous-intensity cadence than participants without ACLR. Increasing the time spent at cadence ≥100 steps per minute and overall volume of physical activity may be useful as interventional targets to help reduce the risk of early development of OA after ACLR.