Changes of Muscle Mechanics Associated With Anterior Cruciate Ligament Deficiency and Reconstruction

Abstract

Isometric and isokinetic knee strength deficits were examined on patients with anterior cruciate ligament (ACL) injury before and after ACL reconstruction. Muscle strengths of the uninjured and injured knees were measured from an ACL injured (n = 12) and a control (n = 15) group. Five isometric (10, 30, 50, 70, and 90° of knee flexion) and 5 isokinetic (50, 100, 150, 200, and 250°·s) strengths of quadriceps and hamstrings were measured prereconstruction and postreconstruction (3 and 6 months). Compared with the controls, the uninjured knee showed normal strength and patterns of length-tension and force-velocity relationships. Compared with the uninjured knee, the injured knees showed a generally 25-30% decrease in quadriceps and hamstrings strength with normal patterns of length-tension and force-velocity relationships. By 3 months of reconstruction, weakness of quadriceps of the injured knees was exacerbated, particularly at lengthened positions (∼ 40% of the uninjured knees at knee flexion 70 and 90°) and at slower velocities (∼35% of the uninjured knees at the 50 and 100°·s, p < 0.05), with flattened patterns of mechanical output. By 6 months of reconstruction, the quadriceps of the injured knees still showed significant weakness (∼50% of the uninjured knees) in both contraction types (isometric at knee flexion 90° and isokinetic at 50°·s, p < 0.05). The hamstrings of the injured knees had not shown significant changes after reconstruction. A strengthening program placing emphasis on greater knee flexion angles and slower movement speed with sufficient training duration post ACL reconstruction is recommended because of long-lasting and exacerbated weakness during 3 and 6 months postreconstruction.

Mapping current research trends on neuromuscular risk factors of non-contact ACL injury

“…ACL-D subjects showed a deficit of the peak quadriceps torque in both isometric testing in males (Urbach, et al, 2001) and isokinetic testing (Konishi, et al, 2011;Tsepis, et al, 2004) in males and females. Another study found quadriceps and hamstring deficits for isometric and isokinetic tests in male and females (Hsiao, et al, 2014). In contrast, one study found greater isokinetic hamstring strength in ACL-D females (Swanik, et al, 2004).…”

“…Two studies demonstrated weaknesses in quadriceps strength that were still present at both 1 and 3 months after injury in males and females during isometric and isokinetic contraction (Drechsler, et al, 2006;Hsiao, et al, 2014). Another study also found a decrement of isokinetic strength in the quadriceps in males (Xergia, et al, 2013).…”

“…Clear and often long-term reductions in muscular capacity were found for quadriceps muscles in ACL-D (Hsiao, et al, 2014;Konishi, et al, 2011;Tsepis, et al, 2004;Urbach, et al, 2001) and ACL-R (Drechsler, et al, 2006;Hsiao, et al, 2014;Xergia, et al, 2013) patients compared to healthy controls suggesting substantial consequences of post-injury inactivity, detrimental effects of kinesiofobia (Drechsler, et al, 2006), autograft repair (Hiemstra, Webber, MacDonald, & Kriellaars, 2004), and potentially lack of rehabilitation compliance. These considerable changes in muscular capacity and likely alterations in muscular activation patterns altogether suggest that risk of re-injury is based on very different factors than risk of primary injury.…”

“…Five case-control studies analyzed deficits in muscular capacity in ACL-D subjects compared to healthy controls (Hsiao, Chou, Hsu, & Lue, 2014;Konishi, et al, 2011;Swanik, Lephart, Swanik, Stone, & Fu, 2004;Tsepis, Vagenas, Giakas, & Georgoulis, 2004;Urbach, Nebelung, Becker, & Awiszus, 2001). ACL-D subjects showed a deficit of the peak quadriceps torque in both isometric testing in males (Urbach, et al, 2001) and isokinetic testing (Konishi, et al, 2011;Tsepis, et al, 2004) in males and females.…”

“…Five case-control studies investigated muscular capacity deficits of ACL-R compared to healthy controls (Drechsler, Cramp, & Scott, 2006;Holsgaard-Larsen, Jensen, Mortensen, & Aagaard, 2013;Hsiao, et al, 2014;Urbach, et al, 2001;Xergia, Pappas, Zampeli, Georgiou, & Georgoulis, 2013). Two studies demonstrated weaknesses in quadriceps strength that were still present at both 1 and 3 months after injury in males and females during isometric and isokinetic contraction (Drechsler, et al, 2006;Hsiao, et al, 2014).…”