Soleus subtendon elongation is reduced by individual suturing of Achilles subtendons after rupture

The primary aim was to evaluate if individual suturing of the gastrocnemius and soleus parts of the ruptured Achilles tendon could reestablish their length 1 week post-surgery compared to previously published results using a standard operative technique. We hypothesised that this new suturing technique would reduce the soleus subtendon length by 50% compared to the standard technique 1 week after surgery (primary endpoint). Secondary aims included soleus and gastrocnemius subtendon lengths at 26 weeks. The ambi-directional design included a retrospective part using a standard Kessler repair of the tendon as a single structure (n&#x2009;=&#x2009;24) and a prospective part using a novel surgery that sutured the soleus and gastrocnemius subtendons separately (n&#x2009;=&#x2009;23). One and 26 weeks after surgery, both groups underwent 3D MRI to determine the length of the soleus and gastrocnemius subtendons. For the soleus subtendon, the individual suturing technique yielded a smaller side-to-side (injured-uninjured) difference (1.9&#x2009;&#xb1;&#x2009;14.7&#x2009;mm) compared to the standard surgery (17.0&#x2009;&#xb1;&#x2009;11.5&#x2009;mm, p&#x2009;<&#x2009;0.0001) at week 1 and week 26 (individual 10.7&#x2009;&#xb1;&#x2009;14.9&#x2009;mm, standard 21.5&#x2009;&#xb1;&#x2009;12.7&#x2009;mm, p&#x2009;<&#x2009;0.0001), although there was an increase in the individual suturing from week 1 to week 26, (p&#x2009;<&#x2009;0.05). The side-to-side difference in gastrocnemius subtendon length was not significantly affected by suturing technique but increased with time for individual suturing from week 1 (-1.5&#x2009;&#xb1;&#x2009;10.6&#x2009;mm) to week 26 (9.2&#x2009;&#xb1;&#x2009;9.4&#x2009;mm, p&#x2009;<&#x2009;0.0001), and for standard suturing from week 1 (1.8&#x2009;&#xb1;&#x2009;11.1&#x2009;mm) to week 26 (8.4&#x2009;&#xb1;&#x2009;10.9&#x2009;mm, p&#x2009;<&#x2009;0.0001). Using an individual suturing approach, soleus and gastrocnemius subtendon lengths were nearly restored to normal values 1 week postoperatively. Subsequent elongation of the soleus subtendon over 6 months was also significantly less with individual suturing than standard surgical repair. Level III.