ACL Bracing - Clinical Studies



ACL injuries per year occur in the U.S.3




ACL injuries per year occur in the U.S.3

Women Are



ACL Injury

Facts & Figures

Risk of ACL injury to contralateral knee is 2-3 times that of the reconstructed knee

Contributing Factors

  • Decreased knee flexion angle1
  • Anterior tibial shear forces2
  • Combined valgus and knee internal rotation moments2
  • Combined valgus and knee external rotatinon2


  • The re-injury rate for the ACL reconstructed knee is 1.8%-10.4%6
  • Risk of ACL injury to the contralateral knee is double that of the reconstructed knee6
  • Only 1/3 of reconstructed athletes attempt to play competitive sports at their pre-injury level within one year following reconstruction7
  • Fear of re-injury prevented competitive college and high school football players from returning to play8
  • Re-injury rate is 6x greater compared to previously uninjured patients9
  • Re-injury rate is 5x higher in females compared to healthy females9
  • Females are 2x more likely to have an injury to the contralateral knee compared to the previously affected knee9
  • For every month that return to sports was delayed until 9 months post ACL-reconstruction, the rate of knee re-injury was reduced by 51%10




  • Significantly increases knee flexion angle at peak posterior ground reaction force (PPGRF) by 9° vs. a standard braced knee and a non-braced knee18,20
  • Significantly decreases PPGRF during stop jump task landing and side-cutting activities18
  • No significant performance limitations were associated with the knee brace with FourcePoint hinge technology18



ACL strain values produced by anterior tibial loading.
Braces utilizing 4-Points-of-Leverage technology effectively reduce ACL strain which could be particularly important during rehabilitation while the graft is remodeling.12,13,14

Wearing a 4-Points-of-Leverage™ brace:

  • Decreases ACL strain by 50% for anteriorly directed loads during weight bearing and non-weight bearing activities12, 13
  • Significantly reduces tibial rotation vs. unbraced and sleeved groups16
  • May improve both proprioception and postural control17
  • Increases patient confidence after ACL reconstruction18




FourcePoint hinge increases flexion angles, reducing anterior shear forces and strain on the ACL and thus significantly decreasing the chance of injury.

FourcePoint hinge improves joint mechanics of both knees post ACL surgery.

The anterior shear force applied on the tibia was reduced by 9% for females & 13% for males.21

The decrease in anterior shear force on the tibia should substantially reduce the load on the ACL.19, 21

ACL Injury


Prophylactic bracing can significantly reduce the number of knee ligament injuries.


Reducing the risk of high impact knee ligament injuries

Prophylactic brace use


  • May be effective in reducing the risk of incurring an MCL sprain in football, and generally provide 20-30% greater MCL resistance to a lateral blow25
  • Reduces injury rates among college football players, linemen, linebackers and tight ends when worn in both practices and games vs. unbraced players24, 27
  • An internal analysis at a major Division I university football program, the number of days lost due to knee injury (and related associated healthcare costs) was reduced by 99% from year 1 to year 2 through the use of a custom fitted prophylactic knee brace in the 2nd year29

Off-road Motorcycling

  • Reduces ACL injury rates by 50% with a 7-fold decrease in MCL injury rates26


  • Reduces ACL reinjury by 3-times compared to non-braced28


Reducing the risk of injury to the contralateral knee

Wearing NO brace or a knee brace without FourcePoint™ hinge technology (results at 6-12 months post-op)

  • 30% deficit in joint mechanics30
  • Asymmetry of mechanics in both knees30


prescribe confidence

A brace equipped with 4-Points-of-Leverage plus FourcePoint is a clinically-proven combination to protect and prevent injury to the ACL.

Clinical Biomechanics Review

  • Training with FourcePoint™ hinge will encourage the knee to stay out of the “at risk” position (0⁰-30⁰ of flexion)
  • Training effect with FourcePoint hinge will be retained despite intermittent brace wear
  • Rehab training after ACL reconstruction without a FourcePoint hinged brace leads to abnormal joint mechanics of both knees
  • Rehab training after ACL reconstruction with a FourcePoint hinged brace improves joint mechanics in both knees
  1. Markolf KL, Gorek JF, Kabo JM, et al. Direct measurement of resultant forces in the anterior cruciate ligament. Journal of Bone & Joint Surgery, Am. 1990 72:557-567.
  2. Shimokochi Y, Shultz SJ. Mechanisms of Noncontact Anterior Cruciate Ligament Injury.
  3. Journal of Athletic Training. 2008 43:4. 396-408.
  4. Griffin LY, Albohm MJ, Arendt, EA, et al. Understanding and Preventing Noncontact Anterior Cruciate Ligament Injuries: A Review of the Hunt Valley II Meeting, January 2005. American Journal of Sports Medicine. 2006 34:9. 1512-1532.
  5. Arendt EA, Agel J, Dick R. Anterior cruciate ligament injury patterns among collegiate men and women. Journal of Athletic Trianing. 1999;34(2):86-92.
  6. Silvers HJ, Mandelbaum BR. Prevention of anterior cruciate ligament injury in the female athlete. Br J Sports Med. 2007; 41 (Suppl I):i52-i59.
  7. Wright RW, Magnussen RA, Dunn WR, Spindler KP. Ipsilateral Graft and Contralateral ACL Rupture at Five Years or More Following ACL Reconstruction. Journal of Bone and Joint Surgery, Am. 2011;93:1159-1165.
  8. Ardern CL, Webster KE, Taylor NF, Feller JA. Return to pre-injury level of competitive sports after anterior cruciate ligament reconstruction surgery: Two-thirds of patients have not returned by 12 months after surgery. Am J Sports Med 2011; 39(3):538-5438.
  9. Spindler KP et al. Return to high school and college level football following ACL reconstruction. 2012 ACL Study Group Meeting. Jackson Hole, WY.
  10. Paterno, MV, Rauh, MJ, Schmitt, LC, Ford, KR, Hewett, TE. Incidence of Second ACL Injuries 2 years after Primary ACL Reconstruction and Return to Sport. The American Journal of Sports Medicine, 2014 42:7 1567-1573
  11. Grindem H, et al. British Journal of Sports Medicine. 2016. 50:804-808
  12. Beynnon BD, Pope MH, Wertheimer CM, Johnson RJ, Fleming BC, Nichols CE, Howe JG.
  13. Journal of Bone & Joint Surgery, Am. 1992; 74:1298-1312.
  14. Beynnon BD, Johnson RJ, Fleming BC, Peura G, Renstrom PA, Nichols CE. American Journal of Sports Medicine. 1997; 25(3):353-360.
  15. Fleming BC, Renstrom PA, Beynnon BD, Engstrom B, Peura G. The Influence of Functional Knee Bracing on the Anterior Cruciate Ligament Strain Biomechanics in Weightbearing and Nonweightbearing Knees. American Journal of Sports Medicine. 2000; 28 (6): 815-824.
  16. Giotis D et al. Knee braces can decrease tibial rotation during pivoting that occurs in high demanding activities. Knee Surg Sports Traumatol Arthrosc. 2011 Aug;19(8): 1347-54 5.
  17. Palm HG, et al. Effects of Knee Bracing on Postural Control after ACL Ligament Rupture. 2011 Aug 24 []
  1. Risberg MA, Beynnon BD, Peura GD, Uh BS. Proprioception after anterior cruciate ligament reconstruction with and without bracing. Knee Surg Sports Traumatol Arthrosc. 1999;7(5):303-9
  2. Lin CH, Liu H, Garrett WE, Yu B. Effects of Knee Extension Constraint Brace on Selected Lower Extremity Motion Patterns During a Stop-Jump Task. Journal of Applied Biomechanics.2008;4:158-165.
  3. Markolf KL, Gorek JF, Kabo JM, et al. Direct measurement of resultant forces in the anterior cruciate ligament. Journal of Bone & Joint Surgery, Am. 1990; 72:557-567.
  4. Stanley C, Creighton R, Gross M, Garrett W, Yu B. Effects of a Knee Extension Constraint Brace on Lower Extremity Movements after ACL Reconstruction. Clinical Orthopaedics and Related Research. 2011; 469(6):1774-1780.
  5. Yu B, Herman D, Preston J, Lu W, Kirkendall DT, Garrett WE. Immediate Effects of a Knee Brace with a Constraint to Knee Extension on Knee Kinematics and Ground Reaction Forces in a Stop-Jump Task. American Journal of Sports Medicine. 2004;32:1136-1143. Nunley et al.
  6. 2003
  7. Nunley RM, Wright DW, Renner JB, Yu B, Garrett WE. Gender Comparison of Patella-Tendon Tibial Shift Angle with Weight-Bearing. Res Sports Med. 2003; 11:173-185.
  8. Albright JP et al. Medial Collateral Ligament Knee Sprains in College Football: Effectiveness of Preventive Braces. American Journal of Sports Medicine.1994 22:1. 12-18.
  9. Najibi S, Albright JP. The Use of Knee Braces, Part 1: Prophylactic Knee Braces in Contact Sports. American Journal of Sports Medicine. 2005 33:4:602-611.
  10. Sanders MS, Cates RA, Baker MD, Barber-Westin SD, Gladin WM, Levy MS. Knee Injuries and the Use of Prophylactic Knee Bracing in Off-road Motorcycling: Results of a Large-Scale Epidemiological Study. American Journal of Sports Medicine. 2011;39:1395-1400.
  11. Sitler M et al. The Efficacy of a Prophylactic Knee Brace to Reduce Knee Injuries in Football: A Prospective, Randomized Study at West Point. American Journal of Sports Medicine. 1990; 18(3):310-315.
  12. Sterett WI, Briggs KK, Farley T, Steadman JR. Effect of Functional Bracing on Knee Injury in Skiers with Anterior Cruciate Ligament Reconstruction: A Prospective Cohort Study. 2006; 34:1581-1585.
  13. Walters DR. Research Tackles Prophylactic Knee Bracing. Biomechanics. An internal analysis conducted at a major Division I university. December 2000; 7:12, 34-37.
  14. Queen R, Butler RJ, Dai B, Garrett WE. Effects of Knee Extension Constraint Bracing on Lower Extremity Motion Patterns in Post-ACL Reconstruction Patients. Interim report of six and twelve month data from the ongoing study, 2012.