Rate of Force Development as an Adjunctive Outcome Measure for Return-to-Sport Decisions After Anterior Cruciate Ligament Reconstruction

Abstract

Study Design Descriptive, prospective, longitudinal single-cohort study. Objective To investigate the rate of force development to 30% (RFD30), 50% (RFD50), and 90% (RFD90) of maximal voluntary isometric contraction (MVIC) as an adjunct outcome measure for determining readiness for return to sport following an anterior cruciate ligament (ACL) reconstruction. Background One criterion of full recovery following an ACL reconstruction is the ability to achieve 85% or 90% of the maximal strength of the contralateral limb. However, the time required to develop muscular strength in many types of daily and sports activities is considerably shorter than that required to achieve maximal strength. Therefore, in addition to maximal strength, neuromuscular functions such as RFD should also be considered in the definition of recovery. Methods Forty-five male professional soccer players who underwent an ACL reconstruction were recruited. Assessment with the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Tegner score, and KT1000 instrumented arthrometer was performed postinjury/prereconstruction and at 6 and 12 months after ACL reconstruction. MVIC, RFD30, RFD50, and RFD90 testing was performed preinjury, as part of standard preseason assessment, and at 6 and 12 months post-ACL reconstruction. Results The average MVIC value 6 months postreconstruction was 97% of the preinjury average value. In contrast, at 6 months, the RFD30, RFD50, and RFD90 values were 80% (P = .04), 77% (P = .03), and 63% (P = .007), respectively, of the preinjury values. The mean RFD values for the reconstructed knee attained or exceeded 90% of the preinjury mean values only at the 12-month post-ACL reconstruction assessment (RFD30, P = .86; RFD50, P = .51; RFD90, P = .56). Conclusion Despite the near recovery of MVIC strength to preinjury levels, there were still significant deficits in RFD at 6 months post-ACL reconstruction. An RFD similar to the preinjury RFD was achieved at 12 months post-ACL reconstruction, following a rehabilitation program focusing on muscle power. These results suggest that, following an ACL reconstruction, RFD criteria may be a useful adjunct outcome measure for the decision to return athletes to sports. J Orthop Sports Phys Ther 2012;42(9):772–780, Epub 19 July 2012. doi:10.2519/jospt.2012.3780

Quadriceps Function and Hamstrings Co-Activation After Anterior Cruciate Ligament Reconstruction

“…19 The ability to produce quick or explosive movements is often more important than muscle strength 19 in sporting activities, and speed rather than magnitude is associated with self-reported physical function in individuals with ACLR. 20 Therefore, the rate of torque development (RTD) is an important indicator of quadriceps function in individuals with ACLR 21 and is associated with greater ground reaction forces and loading rates during walking gait.…”

“…Injured individuals had undergone unilateral ACLR and were cleared by a physician for participation in physical activity. Uninjured participants were matched to individuals with ACLR on sex, age (61 year), body mass index (61 kg/m 2 ), and Tegner Activity Scale score 21 (61). The university's institutional review board approved the study, and all participants provided written informed consent before data collection.…”

Which Outcome Measures Should Be Used to Determine Readiness to Play After ACL Reconstruction?

“…10 Mean RFD for the reconstructed knees did not reach 90% of preinjury values until 12 months after surgery. 10 ACL injury may limit an athlete's ability to RTP at a high level even after surgical reconstruction and diligent rehabilitation. Survey data indicated that 35% to 57% of recreational athletes were unable to return to their previous sport activities after ACLR.…”

“…The ability to generate force quickly during athletics may be important for successful performance and for protection against injury. In a prospective analysis, Angelozzi et al 10 reported that RFD values were only 63% to 80% of preseason/ preinjury values 6 months post-ACLR. 10 Mean RFD for the reconstructed knees did not reach 90% of preinjury values until 12 months after surgery.…”

“…In a prospective analysis, Angelozzi et al 10 reported that RFD values were only 63% to 80% of preseason/ preinjury values 6 months post-ACLR. 10 Mean RFD for the reconstructed knees did not reach 90% of preinjury values until 12 months after surgery. 10 ACL injury may limit an athlete's ability to RTP at a high level even after surgical reconstruction and diligent rehabilitation.…”