Rate of force development as an adjunctive outcome measure for return-to-sport decisions after anterior cruciate ligament reconstruction.
METHODS
Descriptive, prospective, longitudinal single-cohort study.


OBJECTIVE
To investigate the rate of force development to 30% (RFD(30)), 50% (RFD(50)), and 90% (RFD(90)) 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, RFD(30), RFD(50), and RFD(90) 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 RFD(30), RFD(50), and RFD(90) 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 (RFD(30), P = .86; RFD(50), P = .51; RFD(90), P = .56).


CONCLUSIONS
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.
Arcamedica Institution, L’Aquila, Italy.
Massimo
M
Angelozzi
Marco
M
Madama
Cristiana
C
Corsica
Vittorio
V
Calvisi
Gianfranco
G
Properzi
Steven T
ST
McCaw
Angelo
A
Cacchio
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D015331:Cohort Studies; D003657:Decision Making; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011446:Prospective Studies; D062707:Return to Work; D012916:Soccer / Q000293:injuries; D055815:Young Adult