[Short-term outcomes of all-inside endoscopic running locked stitch technique for acute achilles tendon ruptures]

Objective: To evaluate the short-term outcomes of all-inside endoscopic running locked stitch technique for acute Achilles tendon ruptures. Methods: This is a retrospective case series study. Forty-eight cases with acute Achilles tendon rupture were treated with the all-inside endoscopic running locked stitch technique from April 2020 to March 2022 at Department of Orthopaedics, General Hospital of Central Theater Command. There were 44 males and 4 females, aged (34.8±7.4) years (range: 24 to 50 years). Body mass index was (21.2±2.4)kg/m² (range: 18 to 26 kg/m²); There were 29 cases (60.4%) on the left side and 19 cases (39.6%) on the right side. Under endoscopic control, the proximal tendon stumps were stitched with the running locked method using a semi-automatic flexible suture passer. The threads of the high-strength suture were grasped through the paratenon sub-space and then fixed into calcaneal insertion with a knotless anchor. MRI of Achilles tendon was performed to observe the regeneration of Achilles tendon during follow-up. Surgical time and complications were assessed. Achilles tendon total rupture score (ATRS), Achilles tendon resting angle, and heel rise height were utilized to evaluate final clinical outcomes. The differences of bilateral limbs were compared using the paired sample t test. Results: The follow-up time was (24.1±3.5)months (range:18 to 32 months). Appropriate tendon regeneration was observed on MRI at 12 months after operation. The median ATRS score (M(IQR)) was 95.0 (4.7) points. Furthermore, there was no significant difference between the injured and contralateral side in the Achilles tendon resting angle ((17.1±2.4)° vs. (17.4±2.6)°, t=1.92,P=0.062) and heel rise height ((14.2±1.7)cm vs. (14.4±1.5)cm, t=1.71,P=0.094). No nerve injury, infection, deep vein thrombosis and re-rupture was encountered. Sports activity resumed six months postoperative in 46 patients. One patient had a slight anchor cut-out, due to an addition injury, which was removed after 5 months. Conclusions: All-inside endoscopic running locked stitch technique for acute Achilles tendon ruptures shows promising results. It provides stable connection of the tendon stumps with a low risk of complications.