Decreased evertor strength following peroneus longus tendon harvest for anterior cruciate ligament reconstruction

Aims There are conflicting results in the literature regarding the safety of the peroneus longus tendon (PLT) as a potential graft for anterior cruciate ligament (ACL) reconstruction, and no long-term studies with objective assessment exist. Therefore, we assessed the donor ankle following PLT harvest for ACL reconstruction using isokinetic muscle strength testing (IMST) of the evertors and invertors of both feet. Methods The study included 31 patients with a mean age of 32.61 years (SD 10.60) and a mean follow-up period of 18.34 months (SD 6.25). IMST of evertors and invertors of both feet was conducted. Subjective outcomes were assessed using the Foot and Ankle Ability Measure (FAAM) score and the Foot and Ankle Outcome Score (FAOS). To compare the different parameters between timepoints, repeated measures of analysis of variance/Friedman test were used. Results The mean length and diameter of the PLT graft were 29.32 cm (SD 2.26) and 9.32 mm (SD 0.92), respectively. A statistically significant decrease in peak torque at 60°/second was observed at six months for both evertors (p < 0.001) and invertors (p = 0.010). No statistically significant difference in peak torque was observed at one year at 60°/second (evertors: p = 0.386; invertors: p = 0.685) or 120°/second (evertors: p = 0.071; invertors: p = 0.156). The difference in FAAM (p = 0.621) and FAOS (p = 0.456) scores was not statistically significant. Conclusion PLT harvest for ACL reconstruction can initially cause weakness in evertors and invertors. However, ankle-specific rehabilitation may restore strength over time. While overall ankle function remains intact, stronger evidence is needed to support PLT as a primary graft. It may be suitable for select cases, such as multiligament injuries or revisions, with appropriate ankle rehabilitation. Cite this article: Bone Joint J 2026;108-B(6):766–772.