Early weight bearing with ultrasound monitoring is associated with accelerated functional recovery after open repair of acute achilles tendon rupture: a retrospective cohort study

Optimal rehabilitation after open repair of acute Achilles tendon rupture (AATR) remains controversial. Early weight-bearing may enhance recovery, but its clinical use is limited by lack of objective criteria. This study evaluated the safety and efficacy of an ultrasound-monitored early weight-bearing (USEWB) protocol. This retrospective cohort included 64 patients who underwent open AATR repair (March–September 2025), assigned to USEWB ( n = 31) or conventional rehabilitation (CR, n = 33) based on a scheduled institutional protocol change. Three analytical populations were defined: all-allocated, per-protocol, and as-treated. Achilles Tendon Total Rupture Score (ATRS), calf circumference difference (CCD), and Achilles tendon resting angle (ATRA) were assessed at 2, 4, 6, 8, 12, and 16 weeks postoperatively. The primary outcome was the Achilles Tendon Total Rupture Score at 12 weeks postoperatively. Linear mixed-effects models with group-by-time interaction were used. In the all-allocated analysis, the group-by-time interaction was significant for ATRS ( p < 0.001), with USEWB showing higher scores at 12 weeks (difference: 12.025, adjusted p < 0.001). The group-by-time interactions for CCD and ATRA were not significant (CCD p = 0.254; ATRA p = 0.163). Complication rates did not differ significantly between groups (all p > 0.05). Sensitivity analyses (per-protocol and as-treated) yielded consistent patterns. In this retrospective cohort, a USEWB protocol after open AATR repair was associated with accelerated early functional recovery.