NordBord Reveals Persistent Knee Flexor Asymmetry Post-ACL Reconstruction

Study Information  

Högberg J, Piussi R, Simonsson R, Wernbom M, Samuelsson K, Thomeé R, & Senorski EH. The NordBord test reveals persistent knee flexor strength asymmetry when assessed two and five years after ACL reconstruction with hamstring tendon autograft. Physical Therapy in Sport. 2024; 66:53-60. 

https://doi.org/10.1016/j.ptsp.2024.01.008  

Purpose of the Study 

The primary aim of this study was to compare the knee flexor strength limb symmetry index (LSI) from a Nordic test performed on a NordBord with that from an isokinetic concentric test for knee flexors performed on a Biodex System. Additionally, the study aimed to determine the relationship between knee flexor strength and function in patients two and five years after anterior cruciate ligament reconstruction (ACL-R) with hamstring tendon autografts.

Methods and Key Findings  

This observational study analyzed cross-sectional data from 96 patients (45% male, 55% female) who participated in rehabilitation after ACL-R with hamstring tendon autografts. The primary outcomes measured were knee flexor strength symmetry using NordBord and Biodex at two and five years post-surgery.  

Additionally, the study investigated the relationship between knee flexor strength and perceived knee function, activity level and hop performance. Patient demographics, isokinetic concentric knee flexor strength (Biodex), eccentric knee flexor strength (NordBord), hop performance and patient-reported outcome measures (PROMs) were gathered.  

Statistical analyses included paired t-tests, Pearson’s and Spearman’s correlation coefficients and effect size calculations.  

Key results include:  

• At two years post-ACL-R, NordBord demonstrated greater knee flexor strength LSI deficits compared to Biodex (average LSI of 98.7% for Biodex compared to 86.2% for NordBord).  
• At five years post-ACL-R, this pattern held. NordBord continued to demonstrate greater knee flexor strength LSI deficits compared to Biodex (average LSI of 101.2% for Biodex, compared to 90.0% for NordBord).  
• At two years, 88% of patients achieved an LSI of ≥90% using Biodex compared to only 40% using NordBord. At five years, 88% achieved this threshold in Biodex versus 48% in NordBord.  
• No notable correlations were found between knee flexor strength LSI and perceived function, activity level or hop performance.  

VALD’s Solution  

When performed on a NordBord, the Nordic test may be more sensitive in identifying long-term inter-limb deficits in knee flexor strength after ACL-R compared to an isokinetic concentric test on a Biodex. Concentric tests may also be unable to detect persistent strength asymmetries in post-ACL-R populations.  

Clinicians should consider incorporating NordBord testing in post-ACL-R assessments to better detect persistent strength asymmetries that may not necessarily correlate with patient-perceived knee function or activity levels. 

If you would like to know more about how to integrate VALD’s human measurement technology into your organization for enhanced assessment and decision-making, please reach out here.