Ankle Function and Donor-Site Morbidity Following Peroneus Longus Graft Harvesting with or Without Tenodesis to Peroneus Brevis in Anterior Cruciate Ligament Reconstruction

Background/Objectives: The peroneus longus tendon (PLT) is increasingly used as an autograft for anterior cruciate ligament reconstruction (ACLR). However, during PLT harvest, the necessity of distal peroneus longus-to-peroneus brevis (PL-to-PB) tenodesis for the potential preservation of donor ankle function and medial longitudinal arch alignment remains unclear. This study compared ankle function, donor-site morbidity, complications, and weight-bearing radiographic foot alignment after PLT harvest with and without distal tenodesis. Methods: Between January 2020 and December 2024, 92 primary ACLR cases using an ipsilateral PLT autograft were retrospectively screened; 60 patients with available bilateral weight-bearing comparative foot radiographs were included and categorized into a tenodesis group (n = 30) or a non-tenodesis group (n = 30). Ankle outcomes included American Orthopedic Foot and Ankle Society (AOFAS) Ankle–Hindfoot and Foot and Ankle Disability Index (FADI) scores, ankle range of motion (ROM), and donor-site complications. Radiographic alignment was assessed using Meary’s angle and calcaneal pitch angle on bilateral weight-bearing lateral foot radiographs, including side-to-side differences. Results: Follow-up duration was comparable between groups (18.5 ± 4.4 vs. 16.8 ± 3.4 months, p = 0.113). No patient demonstrated clinically relevant loss of ankle range of motion or strength at final follow-up. AOFAS (97.3 ± 4.9 vs. 95.0 ± 5.5, p = 0.078) and FADI (96.8 ± 5.2 vs. 95.3 ± 5.5, p = 0.091) scores were similarly high in the tenodesis and non-tenodesis groups, respectively. Sural nerve sensory disturbance occurred in 6/30 (20.0%) versus 5/30 (16.7%) patients (p = 0.739), and no harvest-site infection was observed. On weight-bearing radiographs, Meary’s angle and calcaneal pitch angle did not differ significantly between groups on the operated side (Meary: 7.99 ± 6.76 vs. 4.76 ± 6.32°, p = 0.061; calcaneal pitch: 23.19 ± 5.94 vs. 21.41 ± 4.64°, p = 0.201) or intact side (Meary: 7.05 ± 6.89 vs. 5.36 ± 6.11°, p = 0.320; calcaneal pitch: 23.33 ± 5.43 vs. 22.00 ± 4.48°, p = 0.305). Side-to-side differences were small and comparable (Δ Meary: 0.94 ± 3.97 vs. −0.60 ± 3.58°, p = 0.120; Δ calcaneal pitch: −0.14 ± 3.35 vs. −0.59 ± 3.29°, p = 0.603). Conclusions: Distal PL-to-PB tenodesis did not appear to provide measurable advantages in donor-ankle patient-reported outcomes or weight-bearing radiographic foot alignment compared with no tenodesis after PLT harvest for ACLR.