The Clinical Effectiveness of the Modified Single-Screw Scarf Osteotomy in Comparison to the Traditional Two-Screw Osteotomy: An Observational Study

Background/Objectives: A short scarf osteotomy involves the conventional “Z”-shaped osteotomy which is shorter in length with promising results. Fixation can be performed with a single screw or two screws. This observational study evaluated the clinical effectiveness of single-screw versus traditional two-screw scarf osteotomies for the correction of hallux valgus deformities. Methods: Forty-eight hallux valgus cases treated between 2019 and 2024 were reviewed. Data collected included patient demographics, operative details, radiological outcomes, and patient-reported outcome measures (PROMs). PROMs were assessed using the Manchester Oxford Foot Questionnaire (MOxFQ) and the visual analogue scale (VAS). A cost analysis was also performed. Results: Fourteen patients (29.2%) underwent traditional two-screw scarf osteotomies. In this group, the hallux valgus angle (HVA) improved from 37.4° to 19.6° (p < 0.001), and the intermetatarsal angle (IMA) improved from 16.5° to 8.9° (p = 0.004). MOxFQ scores decreased from 37.8 to 27.4 (p = 0.139), and VAS scores improved from 7.4 to 3.3 (p = 0.012). Complications were limited to two superficial infections (14.3%). The remaining 34 patients (70.8%) underwent modified single-screw scarf osteotomies. This group demonstrated an HVA improvement from 34.7° to 12.6° (p < 0.001) and an IMA improvement from 15.5° to 7.8° (p < 0.001). MOxFQ scores improved from 39.4 to 10.4 (p < 0.001), and VAS scores decreased from 6.6 to 2.5 (p = 0.002). Complications included three superficial infections (8.8%), two intraoperative fractures (5.9%), and two cases of complex regional pain syndrome (5.9%). Conclusions: The modified single-screw scarf osteotomy appears clinically non-inferior to the traditional two-screw technique. Although wider validation is required, these findings suggest that the single-screw technique may offer an alternative that maintains clinical outcomes while supporting more sustainable healthcare resource use.