Journal of Orthopaedic & Sports Physical Therapy - Charles B. Burns , MSPH, RT(R), DABR

Effect of Knee Angle and Ligament Insufficiency on Anterior Tibial Translation during Quadriceps Muscle Contraction: A Preliminary Report

Michael T. Gross, Alan D. Tyson, Charles B. Burns
Additional information is needed regarding the effects of exercise protocols on the injured or reconstructed anterior cruciate ligament (ACL). The purpose of this investigation was to assess the effects of knee flexion angle and ACL insufficiency on anterior tibial translation (ATT) and patellar ligament insertion angle as subjects performed maximal isometric quadriceps muscle contractions. The subjects were two females and two males between the ages of 18 and 24 who had sustained injuries that resulted in unilateral ACL insufficiency. Each subject performed maximum isometric quadriceps muscle contractions with each leg on a Cybex^® II dynamometer at each of three positions: 15, 45, and 75° knee flexion. A lateral knee roentgenogram was obtained as each subject maintained each isometric muscle contraction. A roentgenogram also was taken as subjects rested each knee in each of the three target positions. Anterior tibial translation for each isometric muscle contraction was assessed by measuring the anterior displacement of the tibial plateau on the isometric resisted roentgenogram relative to the resting roentgenogram. Patellar ligament insertion angle also was measured for each roentgenogram. Maximum ATT occurred at the 15° knee flexion target angle for two subjects and at the 45° target angle for the other two subjects. Patellar ligament insertion angle decreased as knee flexion angle increased. Appreciable stress may be imposed on the ACL as patients perform maximum quadriceps muscle contractions in positions of terminal knee extension and in midrange positions previously reported as being safe for maximal effort quadriceps exercise. Magnitude of stress imposed on the ACL is discussed as a function of the length-tension relationship of the quadriceps muscle-tendon unit and insertion angle of the patellar ligament. Suggestions are made for additional research regarding appropriate muscle strengthening protocols for patients who have undergone ACL reconstruction.

J Orthop Sports Phys Ther 1993;17(3):133-143.

Key Words: biomechanics, rehabilitation, roentgenogram

Changes in Pain and Disability Secondary to Shoe Lift Intervention in Subjects With Limb Length Inequality and Chronic Low Back Pain: A Preliminary Report

Yvonne M. Golightly, Jeremiah J. Tate, Charles B. Burns, Michael T. Gross

STUDY DESIGN: Preassessment and postassessment of treatment intervention. OBJECTIVE: To determine the changes in pain and disability secondary to shoe lift intervention for subjects with chronic low back pain (LBP) who have a limb length inequality (LLI). BACKGROUND: Previous reports have suggested that LLI may be a cause of LBP. Most prior studies of lift therapy for management of LLI in patients with LBP have lacked clear guidelines for clinicians regarding the implementation of shoe lift intervention. METHODS AND MEASURES: Twelve subjects (6 male, 6 female) between the ages of 19 and 62 years with LLI (6.4-22.2 mm) and chronic LBP (1-30 years) participated. Visual analog scale (VAS) pain ratings and disability questionnaire scores were acquired before and after lift intervention. Subjects determined their lift height based on resolution of LBP symptoms. RESULTS: Subjects experienced relief of general pain symptoms (P = .0006) and pain associated with standing (P = .002) following lift intervention, with minimally clinically important (MCID) reductions in general pain for 9 of 12 subjects and MCID reductions in standing pain for 8 of 10 subjects. Subjects also had less disability on the disability questionnaire (P = .001) following the intervention, with 9 of 12 subjects experiencing MCID reductions in disability. CONCLUSION: Shoe lifts may reduce LBP and improve function for patients who have chronic LBP and an LLI. Randomized controlled trials are needed to assess the efficacy of this intervention.

J Orthop Sports Phys Ther. 2007;37(7):380-388, published online 29 May 2007. doi:10.2519/jospt.2007.2429

KEY WORDS: leg length inequality, low back pain, rehabilitation

Reliability and Validity of Rigid Lift and Pelvic Leveling Device Method in Assessing Functional Leg Length Inequality

Michael T. Gross, Charles B. Burns, Shane W. Chapman, Christopher J. Hudson, Heather S. Curtis, James R. Lehmann, Jordan B. Renner

Clinicians commonly include an assessment of leg length inequality (LLI) as a component of a musculoskeletal examination. Little research is available, however, documenting reliability and validity of clinical methods for assessing LLI. The purpose of this study was to determine the reliability and validity of assessing functional LLI using a pelvic leveling device. Subjects were 19 women and 13 men between the ages of 18 and 55 who reported having a diagnosed or suspected LLI. Clinical determination of LLI was made by placing rigid lifts under the suspected shorter lower extremity until the leveling device indicated that the iliac crests were level. This measurement was made twice by one investigator and once by a second investigator. Standing radiographic measurements of LLI using rigid lifts were used to establish validity of the clinical method. Intraclass correlation coefficients [ICC(2, 1)] and absolute difference values were computed to assess reliability and validity. The mean absolute difference between the 2 clinical measurements of LLI by the same investigator was 0.29 cm (± 0.52), with an ICC = 0.84. The mean absolute difference between clinical measurements of LLI by the 2 investigators was 0.49 cm (± 0.46), with an ICC = 0.77. The ICC and mean absolute difference reflecting agreement between radiographic measurements and clinical measurements of LLI was 0.64 and 0.58 cm (± 0.58), respectively, for one investigator and 0.76 and 0.55 cm (± 0.37), respectively, for the second investigator. The intratester reliability, intertester reliability, and validity assessments included instances in which paired observations disagreed regarding which lower extremity was the shorter lower extremity. Factors that may be associated with the unacceptable reliability and validity of the clinical assessment method include asymmetric positioning of the ilia, body composition of the patient, and design of the clinical instrument. The authors discuss clinical implications related to assessment of LLI.

J Orthop Sports Phys Ther. 1998;27(4):285-294.

Key Words: method, lower extremity, leg length, measurement