Biomechanical Measures During Landing and Postural Stability Predict Second Anterior Cruciate Ligament Injury After Anterior Cruciate Ligament Reconstruction and Return to Sport

1. Mark V. Paterno, PT, MS, SCS, ATC*†‡§‖¶,
2. Laura C. Schmitt, PT, PhD†‡§#,
3. Kevin R. Ford, PhD, FACSM†‡‖,
4. Mitchell J. Rauh, PT, PhD, MPH, FACSM¶,
5. Gregory D. Myer, MS, CSCS†‡,a,
6. Bin Huang, PhD†,b and
7. Timothy E. Hewett, PhD, FACSM†‡‖,c

+Author Affiliations

1. ^†Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
2. ^‡Sports Medicine Biodynamics Center and Human Performance Laboratory, Cincinnati, Ohio
3. ^§Division of Occupational Therapy and Physical Therapy, Cincinnati, Ohio
4. ^‖Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio
5. ^¶Graduate Program in Orthopaedic and Sports Sciences, Rocky Mountain University of Health Professions, Provo, Utah
6. ^#Department of Physical Therapy, Ohio State University, Columbus, Ohio
7. ^aGraduate Program in Athletic Training, Rocky Mountain University of Health Professions, Provo, Utah
8. ^bDepartment of Epidemiology and Biostatistics, Cincinnati, Ohio
9. ^cDepartments of Orthopaedic Surgery, College of Medicine and the Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio and The Ohio State University

1. *Mark V. Paterno, PT, MS, SCS, ATC, Cincinnati Children’s Hospital, 3333 Burnet Avenue, MLC 10001, Cincinnati, OH 45229 (e-mail: mark.paterno@cchmc.org).

Abstract

Background: Athletes who return to sport participation after anterior cruciate ligament reconstruction (ACLR) have a higher risk of a second anterior cruciate ligament injury (either reinjury or contralateral injury) compared with non–anterior cruciate ligament–injured athletes.

Hypotheses: Prospective measures of neuromuscular control and postural stability after ACLR will predict relative increased risk for a second anterior cruciate ligament injury.

Study Design: Cohort study (prognosis); Level of evidence, 2.

Methods: Fifty-six athletes underwent a prospective biomechanical screening after ACLR using 3-dimensional motion analysis during a drop vertical jump maneuver and postural stability assessment before return to pivoting and cutting sports. After the initial test session, each subject was followed for 12 months for occurrence of a second anterior cruciate ligament injury. Lower extremity joint kinematics, kinetics, and postural stability were assessed and analyzed. Analysis of variance and logistic regression were used to identify predictors of a second anterior cruciate ligament injury.

Results: Thirteen athletes suffered a subsequent second anterior cruciate ligament injury. Transverse plane hip kinetics and frontal plane knee kinematics during landing, sagittal plane knee moments at landing, and deficits in postural stability predicted a second injury in this population (C statistic = 0.94) with excellent sensitivity (0.92) and specificity (0.88). Specific predictive parameters included an increase in total frontal plane (valgus) movement, greater asymmetry in internal knee extensor moment at initial contact, and a deficit in single-leg postural stability of the involved limb, as measured by the Biodex stability system. Hip rotation moment independently predicted second anterior cruciate ligament injury (C = 0.81) with high sensitivity (0.77) and specificity (0.81).

Conclusion: Altered neuromuscular control of the hip and knee during a dynamic landing task and postural stability deficits after ACLR are predictors of a second anterior cruciate ligament injury after an athlete is released to return to sport.

For further information: http://ajs.sagepub.com/content/38/10/1968.abstract

Predictors of Activity Level 2 Years After Anterior Cruciate Ligament Reconstruction (ACLR)

A Multicenter Orthopaedic Outcomes Network (MOON) ACLR Cohort Study

1. Warren R. Dunn, MD, MPH,
2. Kurt P. Spindler, MD*† and
3. the MOON Consortium‡

+Author Affiliations

1. ^*Vanderbilt University Medical School, Nashville, Tennessee

1. †Kurt P. Spindler, MD, Vanderbilt Sports Medicine, 1215 21st Avenue South, Nashville, TN 37232-8774 (e-mail: kurt.spindler@vanderbilt.edu).

1. Presented at the 33rd annual meeting of the AOSSM, Calgary, Alberta, Canada, July 2007.

1. Annunziato Amendola, MD; Brian R. Wolf, MD, MS; Jack T. Andrish, MD; John A. Bergfeld, MD; Morgan H. Jones, MD; Richard D. Parker MD; David C. Flanigan, MD; Christopher C. Kaeding, MD; Robert G. Marx, MD, MS; Matthew J. Matava, MD; Rick W. Wright, MD; Eric C. McCarty, MD; Michelle Wolcott, MD; Armando Vidal, MD; Frank E. Harrell Jr, PhD; Robert S. Dittus, MD, MPH.

Abstract

Objective: The study was conducted to quantify activity level 2 years after anterior cruciate ligament reconstruction and identify explanatory variables measured at baseline (demographics, concomitant meniscal/articular cartilage injuries and their treatment) associated with activity level at short-term follow-up (2 years).

Study Design: Cohort study; Level of evidence, 2.

Methods: In 2002, the Multicenter Orthopaedic Outcomes Network (MOON) consortium began enrolling patients undergoing anterior cruciate ligament reconstruction at 6 recruitment sites. The current study reports 2-year follow-up of patients enrolled in 2002. Participants completed a series of validated, patient-oriented questionnaires that included activity level assessment. Measurement of intra-articular pathology, techniques of anterior cruciate ligament reconstruction, and secondary procedures were recorded at baseline by participating surgeons. Multivariable proportional odds ordinal logistic regression was used to assess predictors of activity level after adjusting for baseline patient characteristics. Interquartile range (IQR) odds ratios (ORs) are given for continuous variables. The fitted model that used ORs to specify predicted probabilities of exceeding any activity level was translated into predicted mean activity level.

Results: Of the 446 patients who underwent unilateral anterior cruciate ligament reconstruction, follow-up was obtained on 393 (88%). Male patients comprise 56% of the cohort, with a median age of 23 years. The median and IQR International Knee Documentation Committee subjective score was 53 (range, 40-65) preoperatively and increased to 84 (range, 74-92) 2 years postoperatively. Median and IQR activity level was 12 (range, 8-16) at baseline, and declined to 9 (range, 3-13) at follow-up. The proportion of participants returning to the same or higher level of activity 2 years after anterior cruciate ligament reconstruction was 45%. After controlling for other baseline factors such as age, marital and student status, contralateral knee status, sport and competition level, and articular cartilage/meniscal injuries, factors associated with higher activity levels at 2 years were higher baseline activity (IQROR = 3.84; 95% confidence interval [CI], 1.98-7.43; P < .0001) and lower baseline body mass index (IQROR = 1.37; 95% CI, 1.04-1.82; P = .027). The following baseline factors were associated with lower activity: female sex (OR = 0.60; 95% CI, 0.39-0.91; P = .015), smoking within 6 months prior to surgery (OR = 0.55; 95% CI, 0.33-0.92; P = 0.023), and revision anterior cruciate ligament reconstruction (OR = 0.41; 95% CI, 0.20-0.83; P = .014). Factors presumably related to functional status of the knee such as the condition of the articular cartilage and menisci, as well as normalcy of the contralateral knee, were not predictive of activity level at 2 years.

Conclusion: (1) Evaluation of posttreatment activity levels should control for patients’ preoperative activity because this is a strong predictor of future activity. (2) Assuming physical activity is an important component of a healthy person, investigation of potential interventions to improve future activity could target modifiable exposures such as weight. (3) Further evaluation is needed to explore the association of sex and revision surgery on activity level following anterior cruciate ligament reconstruction.

For further information: http://ajs.sagepub.com/content/38/10/2040.abstract