Potentially impaired dynamic ankle control despite increased eversion and first-ray plantarflexion strength after peroneus longus tendon harvest for anterior cruciate ligament reconstruction: an observational study.

backgroundThe peroneus longus tendon (PLT) has emerged as a promising graft option for anterior cruciate ligament reconstruction (ACLR), with acceptable outcomes; however, concerns have been raised about potential donor-site morbidity, particularly affecting ankle and foot function.

aimTo evaluate ankle dynamic stability, eversion, and first-ray plantarflexion strength after harvesting PLT for ACLR, besides reporting the effect on foot and ankle functional outcomes and radiological foot parameters.

methodsForty-two patients having a mean age of 31.7 ± 9.95 years who underwent ACLR using a full-thickness PLT autograft with peroneus brevis tenodesis were evaluated preoperatively and at three and six months of follow up. Functional and clinical outcomes were assessed using the AOFAS score, ankle range of motion (ROM), and muscle strength; ankle dynamic stability was evaluated using the Eccentric-Concentric Bodyweight Power Test (ECBPT). In contrast, radiological outcomes included evaluating the Talonavicular Coverage Angle (TNCA), the Calcaneal Pitch angle (CPA), the lateral Talo-first metatarsal angle (lateral Meary's angle), and the Hindfoot Alignment Angle (HFAA).

resultsThe Ankle plantarflexion increased significantly over time (p = 0.014). Eversion ROM demonstrated a small but statistically significant decline over time (p < 0.001). Ankle dorsiflexion and inversion remained stable throughout follow-up (p = 0.55 and 0.65, respectively). Strength of the first ray plantarflexion improved significantly over time (p < 0.001). Eversion power improved but did not reach statistical significance (p = 0.125). ECBPT decreased significantly over time (p < 0.001). Median values decreased from median 9.5 (IQR 6.0-12.0) preoperatively to 7.0 (IQR 4.2-9.8) at three months and 6.5 (IQR 4.2-9.0) at six months (p < 0.001). AOFAS scores were at the ceiling at all time points (median 100 [IQR 100-100] preoperatively, at 3 months, and at 6 months) with a statistically significant, yet clinically meaningless decline over time p < 0.001), which was noticed comparing preoperative to three and six months of follow up, p = 0.005 and 0.008, respectively, and no difference between three and six months, p = 0.157. The CPA showed a slight but statistically significant decline over time (p < 0.001). No changes were noted in TNCA (p = 0.297), lateral Meary's angle (p = 0.913), and HFAA (p = 0.629).

conclusionOverall foot and ankle function, strength, and range of motion did not show clinically relevant deterioration after PLT harvesting; however, we observed potential alteration in dynamic ankle stability and possible decline in the foot longitudinal arch. Further investigation focused mainly on evaluating the PL muscle's primary functions, and longer follow up studies are warranted to reach conclusive evidence regarding the safety and efficacy of PLT for ACLR.