Hip Abductor Strengthening Improves Dynamic Postural Control Deficits In Patients With Patellofemoral Pain Syndrome Molly Schaber, SPT School of Physical Therapy, Regis University, Denver, CO SEBT Measurement of Affected Limb at Baseline and Discharge. RESULTS PURPOSE BACKGROUND METHODSDISCUSSION CLINICAL RELEVANCE The information realized in this study is important for clinicians seeking a cost- effective and easy-to-administer outcome tool for measuring improvements in dynamic postural control in individuals with PFPS. Using a test which allows for a comparison of affected limb to unaffected limb is important and relevant for identifying baseline differences as well as for re-assessing the effects of interventions and identifying if the individual has achieved symmetrical levels of dynamic balance. This may be especially important in an active population for minimizing risk of future re-injury. SubjectAgeGenderHip Abductor Strength (MMT) Physical Therapy Diagnosis 113F4-PFPS 216F3+PFPS 359F3+PFPS 434F4PFPS 512F4-PFPS Subjects Procedures Strength Assessment: Hip abductor strength was measured during the initial evaluation using manual muscle testing (MMT) in side- lying position. Bilateral hip abduction strength was assessed in all subjects throughout the course of treatment as well as at the final discharge visit. Dynamic Postural Control Assessment: Dynamic postural control was assessed using a modified version of the SEBT during the initial evaluation to identify a baseline for all subjects. Although the standard SEBT incorporates 8 reaching directions, in order to improve efficiency and avoid redundancy this study tested individuals in the anterior, posterior and lateral directions. Subjects were instructed to perform a single-limb squat while the non-stance limb maximally reached in each direction (anterior, posterior and lateral), and the reach distance was measured. Tape was used on the gym floor to create intersecting lines, ensuring that subjects were using the same starting point each time. Reach distance was measured in centimeters (cm). A modified SEBT was conducted for each subject bilaterally, at initial evaluation and discharge. All subjects presented to the same outpatient orthopedic clinic in Bothell, WA with primary complaints of unilateral anterior knee pain. Subject 5 did not complete treatment. Females with patellofemoral pain syndrome (PFPS) often present with impairments in posterior hip muscle performance, and demonstrate weakness of hip abductor and external rotator muscles when compared to healthy controls. 1 In addition, females with PFPS demonstrate deficits in hip kinematics, including a pattern of hip adduction and internal rotation, when performing dynamic functional activities such as squatting, running and landing from a jump. 1, 2 Previous research also indicates that hip abductor muscle performance plays an important role in maintaining medial-lateral postural stability, therefore increasing strength may help improve dynamic postural control deficits. 2 Several research findings have proven the Star Excursion Balance Test (SEBT) to be reliable and valid for identifying dynamic balance deficits in individuals with a variety of lower extremity conditions, such as PFPS. 3 In addition, the SEBT has been shown to be responsive to training programs for individuals with lower extremity injuries and can be used as an outcome measure for identifying improvements in dynamic stability following exercise intervention. 3 However, research focusing specifically on the use of a modified version of the SEBT to measure improvements in active females with PFPS following posterior hip muscle strengthening interventions is limited. This study hypothesizes that individuals with PFPS have difficulty maintaining frontal plane knee alignment during dynamic single limb stance activities as a result of hip abductor muscle weakness. Therefore, the purpose of this study is to determine whether an intervention program which focuses on strengthening of hip abductor muscles will result in improvements in dynamic postural control deficits, as measured by a modified SEBT. Procedures, cont. Hip Abductor Strength at Baseline and Discharge All subjects improved hip abductor strength from baseline to discharge. Overall, subjects demonstrated an average increase in hip abductor strength of 25%. Subject 3 had the most significant strength gains, demonstrating a 43% increase. All subjects demonstrated improvements in reach distance with the affected limb when comparing baseline to discharge SEBT measurements. Subjects had the greatest improvements, on average, in the lateral direction. Subjects 1, 3 and 4 all improved the most in the lateral direction, increasing reach by 16%, 15%, and 19% respectively. Subject 2 demonstrated improvements in the lateral direction as well, but greater improvements in the posterior direction, increasing distance reached by 8% when comparing baseline values to discharge values. REFERENCES 1. Lee S, Souza R, Powers C. The influence of hip abductor muscle performance on dynamic postural stability in females with patellofemoral pain. Gait & Posture. July 2012;36(3): Meira E, Brumitt J. Influence of the hip on patients with patellofemoral pain syndrome: a systematic review. S Health: Mult Appr. Sep 2011;3(5): Kinzey SJ, Armstrong CW. The reliability of the Star-Excursion test in assessing dynamic balance. J Orthop Sports Phys Ther. 1998;27(5): Rehabilitation Intervention: All subjects performed the following exercises as part of their strengthening program during treatment sessions: Side-lying clamshells with progression* Side-lying straight leg raise* Bilateral mini-squats, progressing to unilateral mini-squats* Monster walks – yellow or green resistance band Single leg dead lifts Single leg stance with progression Triple threats with physioball *Indicates exercises prescribed for home (3-4x/week, 10 reps x 3) Females with PFPS demonstrated improvements in strength following a specific exercise program intervention focused on hip abductors. All subjects performed the same program, but progression was determined by an individual’s ability to maintain proper hip and knee alignment while performing each exercise, indicating alignment improved as well. Following completion of this exercise program, subjects also demonstrated improvements in single-limb reach distance, as measured by a modified version of the SEBT. The outcomes of this study support the hypothesis that hip abductor strengthening improves dynamic postural control deficits in females with PFPS.