SLR - May 2023 - Michelle K. Yoakim, DPM
Title: Early Tensile Loading in Nonsurgically Treated Achilles Tendon Ruptures Leads to a Larger Tendon Callus and a Lower Elastic Modulus: A Randomized Controlled TrialReference: Rendek Z, Bon Beckman L, Schepull T, et al. Early Tensile Loading in Nonsurgically Treated Achilles Tendon Ruptures Leads to a Larger Tendon Callus and a Lower Elastic Modulus: A Randomized Controlled Trial. Am J Sports Med. 2022;50(12):3286-3298. Published 2022 October. doi:10.1177/036354652211117780
Level of Evidence: Level II, Randomized Controlled Trial
Scientific Literature Review
Reviewed By: Michelle K. Yoakim, DPM
Residency Program: North Colorado Podiatric Medicine & Surgery Residency - Greeley, CO
Podiatric Relevance: Achilles tendon (AT) ruptures are increasingly prevalent. While there is no consensus on whether surgical or nonsurgical treatment is better, the rehabilitation process has shifted towards early loading and motion. The authors of this article aimed to test the effect of early tensile loading rehabilitation on nonsurgically-treated AT ruptures as this has been shown to lead to high tensile strength in surgically treated ruptures. They hypothesized that the shift towards early loading and motion would decrease the overall re-rupture rate with higher elastic modulus, decrease muscle atrophy, and increase patient satisfaction.
Methods: This was a single center study between October 2015 and November 2018 and included 40 nonsurgically treated patients. The patients’ ages ranged from 18-60-years-old patients with an acute complete midsubstance rupture and a positive Thompson test. Nonsurgical treatment began within 2 days of injury and consisted of a cast or removable ankle orthosis (3 wedges; removed at weeks 4, 5, and 6) with the ankle in plantarflexion. At 14 days, ultrasound examinations were done, tantalum beads were percutaneously inserted in the proximal and distal AT aspects to assess material properties and gap elongation (tendon strain), and patients were randomized into parallel groups. At 3 weeks, both groups began unloaded ankle motion exercises; the loaded group also began active rehab using an exercise pedal to create a tensile load increase. At 7 weeks, both groups had the ankle orthosis removed and began crutch walking followed by regular rehab. Clinical follow-up and outcomes were measured at weeks 7, 19, and 52 using roentgen stereophotogrammetric analysis and CT imaging. Measured outcomes included elastic modulus, cross-sectional area, gap elongation, creep, and AT rupture scores (ATRS) for patient-reported outcomes (heel-rise, ankle and calf circumference, and VAS). Statistical analysis included student t test and spearman correlation test.
Results: The primary outcome was tendon elastic modulus at 19 weeks with a mean standard deviation of 95.6 +/- 38.2 MPa for the loaded group and 108 +/- 45.2 MPa for the control; increased over time, but remained lower in the loaded group. Mean tendon cross-sectional area at 19 and 52 weeks was 388 +/- 142 mm2 and 302 +/- 62.4 mm2 in the loaded group and 335 +/- 87.2 mm2 and 252 +/- 49.2 mm2 in the control; increased over time and larger in the loaded group. Mean creep at 7 weeks and gap elongation between 2-7 weeks were higher in the loaded group. ATRS increased for both groups with an interaction between group and time.
Conclusions: The authors concluded that their original hypothesis was incorrect and that early tensile loading actually reduced the elastic modulus but resulted in a thicker, weaker AT. Overall, this article’s results are a welcomed addition to the literature as consensus AT rupture treatment remains elusive. While treatment decisions are largely based on the patient’s specific needs, the results of this article will impact the type of rehabilitation protocol I would recommend for my nonsurgically-treated AT ruptures.