Single-leg hop distance normalized to body height is associated with the return to sports after anterior cruciate ligament reconstruction

Shunsuke Ohji,Kenji Hirohata,Sho Mitomo,Junya Aizawa,Tetsuya Jinno,Takehiro Ohmi,Kazuyoshi Yagishita,Hideyuki Koga

doi:10.1186/s40634-021-00344-z

Abstract

PurposeTo investigate the relationship between single-leg hop distance (SLHD), normalized body height, and return-to-sports (RTS) status after anterior cruciate ligament reconstruction (ACLR) and to identify the cut-off value for SLHD on the operated side.MethodsSeventy-three patients after primary ACLR (median 13.5 months) participated in this cross-sectional study. Participants were divided into ‘‘Yes-RTS’’ (YRTS) or ‘‘No-RTS’’ (NRTS) groups based on a self-reported questionnaire. SLHD was measured, and the limb symmetry index (LSI) and SLHD (%body height) were calculated. A minimum p-value approach was used to calculate the SLHD cut-off points (%body height) on the operated side that were strongly associated with the RTS status. Logistic regression analysis was used to analyse the association between RTS status and SLHD cut-off point (%body height). Isokinetic strength and Tampa scale for kinesiophobia (TSK) were measured as covariates.ResultsAmong 73 patients, 43 (59%) were assigned to the YRTS and 30 (41%) to the NRTS group. The 70% body height cut-off point for SLHD on the operated side was most strongly associated with RTS status. In a logistic regression analysis including other covariates, SLHD (%body height) < 70% and TSK were negatively associated with RTS status. Except for two participants, the LSI of the SLHD exceeded 90% and there was no significant association between the LSI of the SLHD and RTS status.ConclusionEven after improvement in the LSI of the SLHD, planning rehabilitation with the goal of achieving SLHD over 70% body height may be important for supporting RTS after ACLR.Level of evidenceCross-sectional study, Level IV

Highlights

Many athletes with anterior cruciate ligament (ACL) injury undergo ACL reconstruction (ACLR) with the expectation of a return to sport (RTS) at the same level of competition as before the injury [11]
When the single-leg hop distance (SLHD) cut-off point (%body height) on the operated side was set at 70%, the p-value was the SLHD on the operated YRTS NRTS P-value χ2 value side (% body height)
The main finding of this study was that despite a good limb symmetry index (LSI) improvement in SLHD, an SLHD % body height < 70% on the operative side was negatively associated with RTS status

Summary

Introduction

Many athletes with anterior cruciate ligament (ACL) injury undergo ACL reconstruction (ACLR) with the expectation of a return to sport (RTS) at the same level of competition as before the injury [11]. Several previous studies have shown that post-ACLR patients unable to RTS at the same level as before the injury had a smaller limb symmetry index (LSI) in the single-leg hop distance (SLHD) than those able to RTS [4, 16, 17, 34, 35]. It has been reported [21] that the LSI of the SLHD was not associated with RTS status; there is no consensus view. The LSI of the SLHD can be improved by a functional decline on the unoperated side [31, 36] For these reasons, it is necessary to focus on variables other than the LSI when assessing the SLHD

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