SLR - August 2014 - Lan Li
Reference: Tinney A, Khot A, Eizenberg N, Wolfe R, Graham HK. Gastrocsoleus Recession Techniques: An Anatomical and Biomechanical Study in Human Cadavers. Bone Joint J 2014; 96-B: 778–82.
Scientific Literature Review
Reviewed By: Lan Li, DPM
Residency Program: Montefiore Medical Center, Bronx NY
Podiatric Relevance: Equinus is a condition commonly seen in podiatry. Surgical treatment of equinus deformity requires lengthening of the triceps surae using several techniques, including proximal or distal recession of the gastrocnemius, intramuscular lengthening of the gastroc and soleus, recession of the gastroc-soleus or lengthening of the Achilles tendon. The Vulpius procedure describes a lengthening of the conjoined tendon gastroc aponeurosis and soleus fascia by creating a division of the conjoined tendon in the shape of an inverted V. Transverse division has also been described. This article portrays an investigation of the biomechanical and anatomical characteristics of the Vulpius gastrocsoleus recession performed by a single transverse cut in the conjoined tendon.
Methods: Twenty-four legs in 12 human cadavers were studied. Length, proximal width and distal width of the conjoined tendon in Zone 2 were measured, where Zone 2 is the area from the termination of the medial gastrocnemius belly to the distal extent of the soleus fibers. The length of Zone 2 was divided into thirds. The conjoined tendon was then cut transversely at either the junction of the proximal and middle thirds or junction of the middle and distal thirds. Following transection, 40kg of dorsiflexory force was applied and the separation of the conjoined tendon was measured and the midline raphe of the solues identified and resected completely. A 40 kg force was reapplied and the lengthening gap re-measured.
Results: Transverse division of the conjoined tendon resulted in predictable, controlled lengthening of the gastrocsoleus muscle-tendon unit. Division at a proximal level resulted in a mean lengthening of 15.2 mm which increased to 17.1 mm after division of the midline raphé. Division at a distal level resulted in a mean lengthening of 21.0 mm, which increased to 26.4 mm after division of the raphé. These differences were significant (p < 0.001).
Conclusions: This study shows that simple transverse division can achieve controlled lengthening of the conjoined tendon and also demonstrated that the raphe is an important structural component of the soleus that resists lengthening after loading. Zone-2 lengthening was stable, with no ruptures observed following testing up to 40 kg. The amount of lengthening was dependent on the position of transection within Zone-2, with proximal division resulting in significantly less lengthening than distal division. The extent of both proximal and distal lengthening was increased by division of the midline raphe. Clinically, this study emphasized that the procedure can be performed through a very short postereo-medial incision with minimal risk to the lesser saphenous vein and sural nerve.