Time, graft, sex, geographic location, and isokinetic speed influence the degree of quadriceps weakness after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Abstract

PurposeAlthough quadriceps weakness after ACL reconstruction (ACLR) is well documented, the magnitude of reported weakness varies considerably. Such variation raises the possibility that certain patients may be more susceptible to quadriceps weakness after ACLR. This meta‐analysis identified factors explaining between‐study variability in quadriceps weakness post‐ACLR. MethodsStudies between 2010 and 2020 were screened for the following criteria: human subjects, unilateral ACLR, and strength reported both for the ACLR leg and the uninjured or healthy‐control leg. 122 studies met the criteria, resulting in 303 and 152 Cohen’s d effect sizes (ESs) comparing ACLR legs to uninjured legs (a total of 4135 ACLR subjects) and to healthy controls (a total of 1,507 ACLR subjects vs. 1‐193 healthy controls), respectively. Factors (time, graft, sex, activity, mass/height, geographic area, concomitant injury, and type of strength testing) that may affect study ES were examined. ResultsMeta‐regressions indicated an association between time post‐ACLR and study ESs (P < 0.001) and predicted full recovery (ES = 0) to occur at 54–59 months post‐ACLR. When compared to uninjured legs, patients with patellar tendon autografts had greater deficits than studies using hamstring tendon autografts (P = 0.023). When compared to uninjured legs, studies including only males reported greater deficits than studies combining males and females (P = 0.045); whereas when compared to healthy controls, studies combining males and females reported greater deficits than studies with males (P = 0.013). When compared to controls, studies from USA reported greater deficits than studies from Europe (P = 0.003). Increased isokinetic‐testing speed was associated with smaller deficits (P ≤ 0.025). Less than 25% of patients achieved a between‐limb symmetry in quadriceps strength > 90% between 6 and 12 months post‐ACLR. ConclusionTime post‐surgery, graft, sex, geographic location, and isokinetic speed influenced the magnitude of post‐ACLR quadriceps weakness. Patients with patellar tendon autografts demonstrated greater between‐limb asymmetry in quadriceps strength, while female strength deficits were underestimated to a greater extent. A slower isokinetic speed provided a more sensitive assessment of quadriceps strength post‐ACLR. The overwhelming majority of patients were returning to sport with significantly impaired quadriceps strength. Level of evidenceIII.

Comparison of Patient-Reported Outcomes, Strength, and Functional Performance in Primary Versus Revision Anterior Cruciate Ligament Reconstruction

“…Our study is limited by heterogeneity in patient population by sex and graft type, given that postoperative patientreported outcomes and strength assessments may differ by these patient-specific characteristics. 25,28 However, multifactorial ANOVAs between primary and revision ACLR groups revealed no 3-way interactions between revision status, graft type, and sex. Another limitation is that differences in resources for rehabilitation may have existed between patients in the primary and revision ACLR groups who persisted, even when controlled by a single-center RTP protocol.…”

Interlimb Asymmetry in Knee Extension Moment During Double-Leg Squatting Is Associated With Persistent Quadriceps Weakness After ACL Reconstruction

“…This result indicates that a certain number of patients have persistent quadriceps weakness >1 year after ACLR, as shown in previous systematic reviews. 1,22,33 We were not able to reveal the cause-and-effect relationship between quadriceps strength and altered motor control during double-leg squatting because of the cross-sectional design of this study. However, the study results suggest that the asymmetry in knee extension moment during double-leg squatting may be caused by changes in motor control and not simply by insufficiency of quadriceps strength, suggesting that quadriceps weakness and altered motor control may interact.…”

The Associations Between Quadriceps Tendon Graft Thickness and Isokinetic Performance

“…Additionally, a number of systematic reviews and meta-analyses have used isokinetic dynamometry to assess differences in leg extension strength due to graft type 11,14,17,38 and other factors affecting quadriceps weakness. 38…”

“…Similarly, Yapali and Kurklu 41 conducted isokinetic knee extension testing at 60 and 180 degÁs 21 to compare the results of 20 patients with BPTB grafts and 20 patients with HT grafts at 1 year after ACLR. Additionally, a number of systematic reviews and meta-analyses have used isokinetic dynamometry to assess differences in leg extension strength due to graft type 11,14,17,38 and other factors affecting quadriceps weakness. 38 QT harvest for ACLR can be performed using either PT-Q or FT-Q grafts.…”

“…Additionally, a number of systematic reviews and meta-analyses have used isokinetic dynamometry to assess differences in leg extension strength due to graft type 11,14,17,38 and other factors affecting quadriceps weakness. 38 QT harvest for ACLR can be performed using either PT-Q or FT-Q grafts. Xerogeanes et al 40 studied the morphological variations of the QT based on anthropometric data and demonstrated a correlation between patient height and tendon size, supporting the decision to harvest FT-Q grafts in patients with smaller diameter tendons.…”