Functional Outcomes and MRI Results Following Knotless Repair of Acute Achilles Tendon Ruptures

Abstract

Category: Ankle; Sports Introduction/Purpose: The surgical techniques for primary repair of acute Achilles tendon ruptures have evolved from large open incisions to mini-open and percutaneous techniques. Studies have demonstrated that lesser invasive surgical techniques may reduce the risk of post-operative wound complications. Knotless surgical repair of acute Achilles tendon ruptures can be performed through a mini-incision, but still permits a robust re-approximation of the tendon stumps and decreases suture burden through distal anchor fixation in the calcaneus. However, stress shielding and subsequent tendinosis of the distal tendon stump is a theoretical concern with this surgical technique. We hypothesize that our surgical technique allows for a durable repair through a minimally invasive approach, permitting a safe and accelerated rehabilitation protocol, excellent functional outcomes, and absence of distal stump tendinosis. Methods: A multicenter retrospective chart review was performed to identify all patients that underwent primary Achilles tendon repair using a knotless surgical technique with a minimum of one-year follow-up from three orthopedic foot and ankle surgeons’ practices. Exclusion criteria included: age 4 weeks), insertional Achilles tendon ruptures, revision Achilles surgery, peripheral neuropathy, and systemic inflammatory disease. All patients were contacted by phone and asked to return to the office for an MRI, clinical examination, and completion of functional outcome questionnaires. The primary outcome measure was the validated Achilles Tendon Total Rupture Score (ATRS). Secondary outcomes included the Visual Analog Score (VAS), postoperative complications, ankle range of motion, calf circumference, and single-heel rise. MRI was used to assess tendon continuity and healing, tendinosis, muscle atrophy, and bone marrow edema/stress fracture associated with anchor fixation in the calcaneus. MRI interpretation was performed by a single, blinded musculoskeletal radiologist. Results: Forty-three patients were identified with acute Achilles tendon ruptures. There were 36 patients (36/43, 84%) who underwent knotless Achilles tendon repair and agreed to participate in the study. The average time to clinical follow-up was 23.5 months (SD±16.3). The mean postoperative ATRS was 84.6 (SD±19.7). There was no significant difference in calf circumference (p=0.22), dorsiflexion (p=0.07), and plantarflexion (p=0.11) between the unaffected and surgical extremity at latest follow-up. One patient (1/36, 2.8%) experienced a re-rupture. There were no wound complications or neuritis. MRI was obtained in 26 patients (26/36, 72.2%) at an average of 17.5 months (SD±10.1). There were no MRI findings of distal stump tendinosis or calcaneal stress fractures. Thirty-two patients (32/36, 88.8%) returned to the same athletic activities one-year after surgery. Conclusion: There is paucity in the literature on functional outcomes following knotless Achilles tendon repair. In this multicenter study, we found that validated functional outcome scores and return to activity were similar to historical controls, with a low rate of surgical complications. MRI obtained in twenty-six patients (72.2%) at 17.5 months demonstrated an intact tendon without distal tendon stump stress shielding or calcaneal stress fracture. The knotless Achilles tendon repair is a unique surgical technique, minimizing suture burden and postoperative complications, while offering excellent functional outcomes and return to activity at two-year follow-up. The excellent clinical outcomes are corroborated by MRI.