Which Hop Tests Can Best Identify Functional Limb Asymmetry in Patients 9-12 Months After Anterior Cruciate Ligament Reconstruction Employing a Hamstrings Tendon Autograft?

Abstract

Background Hop tests are commonly employed to evaluate functional limb symmetry after anterior cruciate ligament reconstruction (ACLR). Purpose To investigate the ability of eight hop tests to identify functional limb asymmetry in patients after ACLR. Study Design Prospective cohort. Methods Fifty patients were assessed 9-12 months following ACLR. Functional performance on both the operated and non-operated limb was assessed via eight hop tests, assessed in a randomised order. These included the: single (SHD), triple (THD) and triple crossover (TCHD) hop for distance, 6m timed hop (6MTH), single medial (MHD) and single lateral (LHD) hop for distance, single countermovement jump (SLCMJ) and timed speedy hop (TSHT). Differences in Limb Symmetry Indices (LSIs) across hop tests were compared, while Pearson’s correlations were undertaken to investigate the significance and strength of the association between hop test LSIs. Results Significant differences were observed across hop LSIs (p<0.0001). Mean LSIs for the SHD (95.0%), 6MTH (95.0%), THD (96.1%) and TCHD (95.3%) were ≥90% and significantly greater (p<0.05) than the MHD (87.3%), LHD (87.5%), SLCMJ (83.4%) and TSHT (86.5%), which were all <90%. The LSI for the SLCMJ was significantly lower (p<0.05) than all other hop tests. While significant correlations existed across the majority of hop LSIs, the strongest correlations existed between the SHD, THD and TCHD (r=0.70-0.80), and lowest correlations between the TSHT and the other hop tests (r=0.26-0.49). Conclusions The LHD, MHD and TSHT, as well as the SLCMJ in particular, were best able to demonstrate functional limb asymmetry in patients following ACLR. These hop measures should be incorporated into hop test batteries, if the purpose is to detect the presence of lingering functional deficits. Level of Evidence Level 3.

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“…The hop tests are suggested to be the most consistent predictor of subsequent RTS in patients after knee-joint anterior-cruciate-ligament reconstruction [ 40 ], and they present good reliability [ 32 ]. These tests’ frequent usage is partly due to their practical utility and ease of administration [ 4 , 41 ]. The administration of three or four hop tests as the functional component in RTS assessment is common [ 5 , 8 , 42 , 43 , 44 ].…”

“…In general, the distance-based and time-based hop tests are used to detect functional limb asymmetry with the between-limbs differences expressed by the Limb Symmetry Index (LSI). [ 4 ]. Single-leg hop tests are often used and reported in an examination context, for example, in return-to-sport decision-making for patients after anterior cruciate ligament (ACL) reconstruction [ 4 , 5 , 6 , 7 ].…”

“…[ 4 ]. Single-leg hop tests are often used and reported in an examination context, for example, in return-to-sport decision-making for patients after anterior cruciate ligament (ACL) reconstruction [ 4 , 5 , 6 , 7 ]. Nonetheless, some authors indicate that interpreting the LSI’s value alone is insufficient [ 8 , 9 , 10 ].…”

“…Single-leg hop tests are partially criticized for deficient functional performance evaluation of ACL-reconstructed patients [ 13 ]. Not all hop tests might equally be sensitive for detecting between-limbs differences in terms of functional performance [ 4 , 14 ]. Significant issues concerning hop tests are to be seen in terms of subquality criteria like the excellent economy and simplicity.…”

“…Only a few and cheap pieces of equipment are required; therefore, in-field testing can be performed easily. It is also essential that the single-leg hop tests provide some quantifiable measure that can be evaluated at consecutive points in time with broadly accepted parameters like the hop distance, the between-limbs symmetry, and the time of performing the test [ 4 ]. It was proven in many settings that single-leg hop tests provide good to excellent reliability levels in healthy individuals [ 15 , 16 ] and ACL-reconstructed patients [ 7 , 17 , 18 ].…”