Lower Extremity Muscle Strength After Anterior Cruciate Ligament Injury and Reconstruction

Abstract

Arbor. Dr Thomas is now with the Department of Kinesiology, University of Toledo, OH.Context: Quadriceps and hamstrings weakness occurs frequently after anterior cruciate ligament (ACL) injury and reconstruction. Evidence suggests that knee injury may precipitate hip and ankle muscle weakness, but few data support this contention after ACL injury and reconstruction.Objective: To determine if hip, knee, and ankle muscle weakness present after ACL injury and after rehabilitation for ACL reconstruction.Design: Case-control study. Setting: University research laboratory.Patients or Other Participants: Fifteen individuals with ACL injury (8 males, 7 females; age ¼ 20.27 6 5.38 years, height ¼ 1.75 6 0.10 m, mass ¼ 74.39 6 13.26 kg) and 15 control individuals (7 men, 8 women; age ¼ 24.73 6 3.37 years, height ¼ 1.75 6 0.09 m, mass ¼ 73.25 6 13.48 kg).Intervention(s): Bilateral concentric strength was assessed at 608/s on an isokinetic dynamometer. The participants with ACL injury were tested preoperatively and 6 months postoperatively. Control participants were tested on 1 occasion.Main Outcome Measures: Hip-flexor, -extensor, -abductor, and -adductor; knee-extensor and -flexor; and ankle-plantarflexor and -dorsiflexor strength (Nm/kg).Results: The ACL-injured participants demonstrated greater hip-extensor (percentage difference ¼ 19.7, F 1,14 ¼ 7.28, P ¼ .02) and -adductor (percentage difference ¼ 16.3, F 1,14 ¼ 6.15, P ¼ .03) weakness preoperatively than postoperatively, regardless of limb, and greater postoperative hip-adductor strength (percentage difference ¼ 29.0, F 1,28 ¼ 10.66, P ¼ .003) than control participants. Knee-extensor and -flexor strength were lower in the injured than in the uninjured limb preoperatively and postoperatively (extensor percentage difference ¼ 34.6 preoperatively and 32.6 postoperatively, t 14 range ¼À4.59 to À4.23, P .001; flexor percentage difference ¼ 30.6 preoperatively and 10.6 postoperatively, t 14 range ¼ À6.05 to À3.24, P , .05) with greater knee-flexor (percentage difference ¼ 25.3, t 14 ¼À4.65, P , .001) weakness preoperatively in the injured limb of ACLinjured participants. The ACL-injured participants had less injured limb knee-extensor (percentage difference ¼ 32.0, t 28 ¼ À2.84, P ¼ .008) and -flexor (percentage difference ¼ 24.0, t 28 ¼ À2.44, P ¼ .02) strength preoperatively but not postoperatively (extensor: t 28 ¼ À1.79, P ¼ .08; flexor: t 28 ¼ 0.57, P ¼ .58) than control participants. Ankle-plantar-flexor weakness was greater preoperatively than postoperatively in the ACL-injured limb (percentage difference ¼ 31.9, t 14 ¼ À3.20, P ¼ .006).Conclusions: The ACL-injured participants presented with hip-extensor, -adductor, and ankle-plantar-flexor weakness that appeared to be countered during postoperative rehabilitation. Our results confirmed previous findings suggesting greater knee-extensor and -flexor weakness postoperatively in the injured limb than the uninjured limb. The knee extensors and flexors are important dynamic stabilizers; weakness in these muscles could i...

What Can the First 2 Months Tell Us About Outcomes After Anterior Cruciate Ligament Reconstruction?

“…Gerber et al 42 noted that the quadriceps femoris muscle of the surgical limb could atrophy up to 30% just 3 weeks after ACLR, indicating the importance of resistive training immediately after surgery in an effort to mitigate atrophy and weakness. Other investigators 8,9 showed that at 6 months postoperatively, individuals can experience a loss of up to 50% of quadriceps strength relative to the contralateral limb and persistent limb weakness after returning to the previous activity level. Other evidence suggests that mitigating muscular atrophy may reduce the risk of rerupture, minimize patellofemoral pain, lessen mobility deficits, and return athletes to sport more quickly after ACLR.…”

“…Reconstruction of this ligament and postoperative rehabilitation have been shown to be effective in restoring functional stability of the knee, 4 minimizing the development of osteoarthritis (OA), 5,6 and returning patients to their previous level of function. 5,7 However, persistent lower extremity muscle weakness, 8,9 insufficient dynamic knee stability, 10 and increased risk of posttraumatic arthrosis 3 have also been reported. A considerable number of individuals are unable to return to competitive sports despite successful rehabilitation or ACLR with rehabilitation.…”

Persistent Neuromuscular and Corticomotor Quadriceps Asymmetry After Anterior Cruciate Ligament Reconstruction

“…Despite these reports, clinically assessing and detecting quadriceps dysfunction during the terminal phases of rehabilitation remains difficult due to the often subtle reductions in strength and activation. 10,15 The importance of quadriceps function after ACLR cannot be overstated because reduced quadriceps function consistently has been related to long-term quadriceps weakness 10,14 and physical performance 3,16,17 and has been hypothesized to increase the risk for knee-joint osteoarthritis. 7 Assessment and comparison of range of motion and strength are common clinical tools used to track progress throughout the rehabilitation process.…”

ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION & THE HAMSTRINGS Implications for injury prevention & rehabilitation

“…A number of observational studies (Konrath et al, 2016;Nomura et al, 2015;Takeda et al, 2006) have reported decrements in concentric (Tengman et al, 2014) and eccentric (Tengman et al, 2014;Thomas et al, 2013) knee flexor strength in the years following surgery as well as reduced muscle size (Nomura et al, 2015) and altered muscle architecture of the ST (Timmins et al, 2015). However, these studies are almost always constrained by small sample sizes, and several investigations have found conflicting results regarding the recovery of strength after rehabilitation (Aglietti et al, 1994;Ejerhed et al, 2003).…”