The Hemi-Castaing ligamentoplasty for chronic lateral ankle instability does not modify proprioceptive, muscular and posturographic parameters

The Hemi-Castaing ligamentoplasty uses a powerful dynamic stabilizer of the ankle which is the peroneus brevis tendon. To our knowledge, there is no study available evaluating the effects of this type of surgery on proprioceptive, muscular and posturographic parameters. This case-control study included 39 subjects divided into two groups: the operated (n = 24) and the control group (n = 15). All subjects underwent a clinical, proprioceptive and isokinetic assessment using a CON-TREXA (R) dynamometer, and a postural evaluation using the Win-Posturo(A (R)) force platform. At a mean period of 23 (SD 5.4) post-operative months, the Karlsson ankle functional score was 84.2 (SD 23.8) and the AOFAS score was 88.1 (SD 16.2). The mean ankle joint position error for operated ankles was from 1.9A degrees (SD 0.9) at 10A degrees of inversion range of motion to 2.5A degrees (SD 1.7) at 20A degrees. It was similar to that achieved in the control group ranging from 2.2A degrees (SD 1) at 10A degrees to 2.3A degrees (SD 1.3) at 20A degrees. No significant loss of ankle eversion strength could be observed after ligamentoplasty. Ankle eversion/inversion ratio when tested under all velocities and contraction modes failed to reveal any statistical difference between the operated and healthy ankles in the patient group, neither between the patient and control groups. This surgical technique achieved excellent functional outcomes. It did not impair the agonist/antagonist balance of ankle muscles, and use of half the peroneus brevis tendon did not lessen the eversion strength. Case-control study, Level III.