Portable device for measuring isometric plantar-flexion force after open Achilles repair: Retrospective cohort of 30 recreational athletes with one-year minimum follow-up.

Background: Plantar flexion force in recreational athletes after repair of Achilles tendon tears has rarely been reported, due to the lack of a widely available and fast measurement method. Knowledge of this parameter would allow optimisation of muscular and sports recovery. The main objective of this study was to measure the isometric force of the triceps surae at least 1 year after unilateral Achilles-tendon repair, comparatively to the unaffected side, using a portable device. The secondary objectives were to compare Achilles tendon and calf-muscle trophicity, dorsiflexion, and the single-leg heel-rise test versus the normal side and to assess functional scores at last follow-up.
Hypotheses: (i) Plantar flexion force does not differ significantly between the operated and contralateral sides. (ii) Calf-muscle trophicity, dorsiflexion, and the single-leg heel-rise test do not differ significantly between the operated and contralateral sides.
Patients and Methods: This single-centre retrospective study included patients aged 18 to 65 years with a history of open repair of an acute unilateral Achilles tear at least 1 year earlier. Plantar flexion force, calf-muscle trophicity, dorsiflexion, and the heel-to-floor distance were measured on both sides and compared. The ATRS, VISA-A score, and EFAS score were determined. All complications were recorded.
Results: The study included 30 patients with a mean follow-up of 20.3 months (range, 12-28 months). The operated side had significantly lower values for isometric triceps surae force, calf circumference, and heel-to-floor distance compared to the contralateral side (p<0.0001). Tendon width was significantly greater on the operated side (p<0.0001). Dorsiflexion did not differ significantly between sides (p=0.106). Mean functional score values were 91.5±6 for the ATRS (maximum, 100), 85±12 for the VISA-A score (maximum, 100), and 19.5±4 for the EFAS score (maximum, 24).
Discussion: Isometric triceps-surae force measured using a portable device at least 1 year after open surgical Achilles-tendon repair was significantly decreased compared to the contralateral side. Calf circumference and heel-to-floor distance were also significantly lower. These data indicate a need for improved monitoring of triceps surae recovery to optimise rehabilitation and sports resumption.
Level of Evidence: IV, retrospective comparative cohort study.
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