Minimally invasive (ring forceps) versus open Achilles tendon repair: A retrospective comparison of ultrasonographic and functional outcomes

Objective: While surgical repair is standard for acute Achilles tendon ruptures, the optimal technique remains debated. This study com pares clinical, functional, and ultrasonographic outcomes between minimally invasive and open surgical approaches, with particular focus on: (1) patient-reported recovery, (2) tendon healing dynamics, and (3) the utility of ultrasound in postoperative monitoring. Methods: This retrospective study analyzed 108 consecutive patients undergoing surgical repair for acute Achilles tendon ruptures between 2015-2023, comparing minimally invasive (n = 58; ring forceps technique) and open approaches (n = 50; Krackow technique). Functional outcomes were assessed using American Orthopaedic Foot and Ankle Society (AOFAS), Patient-Reported Outcomes Measurement Information System (PROMIS), and Madrid Sonographic Enthesitis Index (MASEI) scores at standardized 6-, 12-, and 24-month follow-ups, while ultrasonographic evaluations quantified tendon thickness at rupture and insertion sites relative to contralat eral tendons. Complication rates and demographic variables were systematically reviewed, with all patients receiving identical postoper ative rehabilitation protocols. Results: A total of 108 patients were included in the study, with a mean age of 41.56 ± 13.98 years (range, 18-68). Minimally invasive sur gery was performed in 58 patients (53.7%), while the remaining 50 patients (46.3%) underwent open surgical repair. The mean follow-up duration was 2.4 years (minimum of 2 years of follow-up). Patients in the minimally invasive group reported significantly higher PROMIS scores compared to those in the open surgery group (P < .001). However, no significant differences were observed in AOFAS or MASEI scores between the groups (P > .05). Ultrasonographic evaluation revealed that the mean tendon thickness at the rupture site was signifi cantly greater in the minimally invasive group (1.04 cm; range, 0.93-1.15) than in the open surgery group (0.87 cm; range, 0.77-0.93) (P < .001). Furthermore, the operated-to-intact tendon thickness ratio was 2.13 in the minimally invasive group and 1.78 in the open surgery group, which was also statistically significantly different (P = .006). Conclusion: Minimally invasive achilles tendon repair was associated with potential advantages compared to open techniques, includ ing more favorable patient-reported outcomes (median PROMIS score 80 vs. 76, P < .001), increased tendon thickness (19% greater, P < .001), a potential indicator of differential healing patterns, and lower wound complication rates, while importantly achieving equivalent high-level function as measured by the AOFAS and MASEI scores. The main limitations of this study include its retrospective design and the potential for unmeasured confounding. Ultrasound serves as a critical postoperative tool, objectively quantifying healing progression and informing return-to-sports decisions. These findings suggest potential advantages of minimally invasive approaches and support their consideration as a viable alternative to open repair in selected patients; however, the choice of technique should be individualized based on surgeon experience and patient-specific factors. However, these associative findings require validation in randomized trials.   Cite this article as: Yigit O, Erdogan MK, Canbaz SB, et al. Minimally invasive (ring forceps) versus open achilles tendon repair: A retrospective comparison of ultrasonographic and functional outcomes. Acta Orthop Traumatol Turc., 2025;59(6):394-404.