Modified Bunnell suture repair versus bundle-to-bundle suture repair for acute Achilles tendon rupture: a prospective comparative study of patients aged <45 years

BACKGROUND: This study aimed to compare the operative outcome of percutaneous repair (modified Bunnell suture technique) versus open repair (bundle-to-bundle suture technique) of acute Achilles tendon rupture. METHODS: Seventy-two consecutive patients who underwent surgical treatment of Achilles tendon rupture were evaluated in this prospective study. Thirty-six patients were treated using the bundle-to-bundle suture technique (group A), and 36 patients were treated using the modified Bunnell suture technique (group B). All patients underwent functional examination comprising measurement of the calf muscle circumference and performance of the single-leg heel-rise test. The length and diameter of the Achilles tendon were compared between the injured and uninjured sides on magnetic resonance imaging. The number of single-leg heel rises (height > 5 cm) performed within 15 s was compared between the injured and uninjured sides. The ankle range of motion was also recorded. The Achilles tendon total rupture score (ATRS), American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale score, and visual analog scale (VAS) pain score were used to evaluate the clinical outcome at 12 months postoperatively. RESULTS: A total of 61 patients were followed up. The mean follow-up duration did not significantly differ between group A (23.73 ± 2.81 months) and group B (22.61 ± 3.96 months). However, there were significant differences between groups in the heel-rise test (group A, 1.74 ± 0.96; group B, 2.37 ± 1.42) and length of the Achilles tendon (group A, 11.98 ± 1.64 cm; group B, 11.11 ± 1.74 cm). The calf circumference of the injured side was significantly larger in group A than in group B (p = 0.043). The cross-sectional diameter of the Achilles tendon was significantly smaller in group A than group B. At final follow-up, there were no significant differences between the two groups in the ATRS, AOFAS score, or VAS score. One patient in group A had delayed wound healing, which resolved in 40 days. CONCLUSIONS: Patients with acute Achilles tendon rupture treated with open repair (bundle-to-bundle suture technique) achieved a better clinical outcome regarding the heel-rise test and calf circumference compared with those treated with percutaneous repair (modified Bunnell suture technique). TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000035229, 8/4/2020, Retrospectively registered.