Walter L. Jenkins

Anterior cruciate ligament injury in female and male athletes: the relationship between foot structure and injury.

BACKGROUND It has been shown that anterior cruciate ligament (ACL) injuries are more prevalent in female athletes than in male athletes. Soccer and basketball are considered high-risk sports for ACL injury in female athletes. Several studies have reported a relationship between ACL injury and measures of foot structure. This study was conducted to investigate the relationship between foot structure and ACL injury rates in female and male soccer and basketball players. METHODS One hundred five soccer and basketball players (53 women and 52 men) were recruited and divided into an ACL-normal group (n=89) and an ACL-injured group (n=16). Two measures of foot structure (subtalar joint neutral position and navicular drop test values) were recorded for each subject. An independent t test and a paired t test were used to analyze differences in ACL status, foot structure, and sex. A chi2 analysis determined whether the prevalence of ACL injury was independent of sport. RESULTS No statistically significant differences were found in the foot structure measures between women and men. Female soccer and basketball players had an ACL injury rate seven times that of male players. CONCLUSIONS Values derived from subtalar joint neutral position measurement and the navicular drop test were not associated with ACL injury in collegiate female and male soccer and basketball players.

The Relationship Between the Use of Foot Orthoses and Knee Ligament Injury in Female Collegiate Basketball Players

BACKGROUND Anterior cruciate ligament injuries are more prevalent in female athletes than in male athletes. Basketball is a high-risk sport for anterior cruciate ligament injury in female athletes. This study was conducted to observe the effect of a foot orthosis on the knee ligament injury rate in female basketball players at one US university. METHODS One hundred fifty-five players on the womens basketball team were observed for knee ligament injury from 1992 to 2005. Athletes in the 1992-1993 to 1995-1996 school years (July-June) did not receive a foot orthosis and served as the control group; the treatment group comprised the athletes during the 1996-1997 to 2004-2005 school years (July-June). Athletes in the treatment group received a foot orthosis before participating in basketball. Data analysis included knee ligament injury rates and a comparison of injury rates with an incidence density ratio. RESULTS Athletes in the control group had three collateral ligament injuries and three anterior cruciate ligament injuries, for an injury rate of 0.50 for both the anterior cruciate ligament and collateral ligaments. Athletes in the treatment group had four collateral ligament injuries and one anterior cruciate ligament injury, for an injury rate of 0.29 for the collateral ligaments and 0.07 for the anterior cruciate ligament. Athletes in the control group were 1.72 times more likely to sustain a collateral ligament injury and 7.14 times more likely to sustain an anterior cruciate ligament injury than the treatment group. CONCLUSIONS Foot orthoses may contribute to a decreased knee ligament injury rate in female collegiate basketball players.

MEASURES OF LIMB SYMMETRY USED FOR INJURY RISK IDENTIFICATION: WHAT IS NORMAL?

Background Limb asymmetries have been identified as a significant predictor of injury risk. However, the natural boundaries of variation in a non-injured population using clinically relevant and reliable measures has not been determined. Objective To assess clinical measures of limb symmetry and determine the natural boundaries of symmetry present in a non-injured population. Design Prospective cohort study. Setting Controlled laboratory research. Participants 39 non-injured participants, 12 male, 27 female (23.2±2.9 years, 170.2±9.1 cm, 68.4±15.6 kg). Assessment of Risk Factors Knee PROM, effusion, endfeel, knee extension, flexion, and hip abduction strength, dynamic balance, single leg hop, and IKDC Subjective rating were measured. Main Outcome Measurements In measures demonstrating excellent reliability (ICC≥0.75, Kappa≥0.81), limb symmetry index (LSI) and variability scores were calculated. Results All clinical measures, except hip abduction strength, demonstrated excellent reliability. Knee extension PROM was 6.0±5.0°, flexion PROM was 154.0±5.0°. 100% of participants had normal knee extension endfeel, and no knee effusion. 95% had normal flexion endfeel. LSI scores for each measure ranged between 96.6–100.0%. Using minimal detectable change (MDC) scores for each measure, boundaries of limb symmetry were calculated for knee extension PROM (100±1.0°), knee flexion PROM (100±4°), knee extension strength (100±21.0%), knee flexion strength (100±24.0%), dynamic balance (100±6.0%), single leg hop (100±9.1%), and IKDC Subjective rating (100±3.3%). Conclusions Most measures of limb symmetry used in the study demonstrated appropriate reliability for clinical use. Although strength measures had high degrees of limb symmetry, there was significant variability present in non-injured participants. Conversely, high levels of limb symmetry with very little variation were observed in knee PROM, dynamic balance, single leg hop, and IKDC Subjective measures. Strength may not be the best measure of limb symmetry while PROM, dynamic balance, single leg hop, and the IKDC Subjective form appear to have more utility to identify limb asymmetries.