Contralateral limb deficit seven months after ACL-reconstruction: An analysis of single-leg hop tests

• We analyze jumping performance, kinematic and kinetic parameters.
• Our results highlight lower jumping distance and height after ACL-reconstruction.
• We observe impaired kinematic and kinetic strategies in the non-injured leg.
• Some deficits are specific to the non-injured leg.
• Implement a pre-surgical assessment and specific exercises for the non-injured leg

BackgroundFollowing ACL-reconstruction, the non-injured leg (NIL) is used as a reference to assess injured leg (IL) recovery. However, deficits have been reported in the NIL questioning its use as a reference. The aim of this study is to assess whether NIL deficits are present while jumping after ACL-reconstruction.MethodsThirteen males who had undergone ACL-reconstruction and 16 healthy subjects took part in the experiment. Jumping performance was assessed during a single and a triple hop for distance. Jumping performance, kinematic and kinetic data were recorded during single leg squat jumps. Values for both the NIL and the IL were compared to those of a control group (CG).ResultsJumping performance for single and triple hop for distance and single leg squat jump was lower in the NIL than in the CG (p = 0.004, p = 0.002, and p = 0.016, respectively). During the squat jump, the knee joint was more extended and the ankle plantar-flexion was greater at take-off while the peak total moment was 15% lower in the NIL than in the CG (p = 0.002, p = 0.002, and p = 0.009, respectively). We found consistent evolutions in the NIL and the IL compared to the CG for jumping performance, initial joint angles, and peak total moment during the squat jump, but the opposite was found for the ankle and knee joint angles at squat jump take-off.ConclusionsJumping strategies are impaired in the NIL after ACL-R during jump tasks with some deficits matching those observed in the IL and some specific to the NIL.Level of evidenceIII, Case control study