The Compound Defects Of Achilles Tendon: The Etiology, The Reconstructive Surgery Designs, And The Applied Anatomy

Background and ObjectiveThe compound injuries of Achilles tendon usually involves the broken, defective and contaminated Achilles tendon, a fractured or defective calcaneus, and defective surrounding soft-tissues. The main cause is spoke injuries. It has been already over 60 years since the first report whereas the incidence of this injury remains high in clinic. The understanding of the injury mechanism is not only imperative, but also necessary for the classifications and surgery protocols. The combined defects of Achilles tendon with its overlying skin requires the reconstruction of both tissues. Traditionally a flap comes first for the wound coverage, and Achilles tendon is reconstructed in the second stage. Bi-pedicled gastrocnemius musculocutaneous flap is an ideal solution for the defects for that it reconstructs both tissues in one stage. This surgery, however, requires the coronal dissection of the distal Achilles tendon for the sliding. Half of the tendon bulk is therefore sacrificed after the coronal separation of the soleus part of the tendon. Hence the plantarflexion strength of Achilles tendon after the surgery drops. It is necessary, therefore, to quantify the sliding distance of the flap via the anatomy study to lessen the donor site morbidity, and to increase the plantarflexion strength of the reconstructed Achilles tendon. In recent years, free perforator flaps, which develops from traditional free flap, grows in popularity. The free perforator flaps theoretically has a larger size than pedicled flaps and a less donor site morbidity than traditional free flap. Combined with tendon grafts, the free perforator flap may accomplish a huge size coverage of the combined defects of Achilles tendon and surrounding soft tissues in one stage. This premise also requires anatomical exploration and clinical study.Materials and Methods:Part I: The etiology and classifications of spoke injuries One hundred and eighty-nine cases of spoke injuries of the heel (bicycle and motorcycle) were studied. The classification of spoke injures was made according to the wound situation and surgery outcomes. The injury mechanism was recorded, and the origin spot of the injury were studied. The surgical protocols were put forward based on the classifications.Part II: The compound defects of Achilles tendon: the anatomy and clinic application of the modified bi-pedicled gastrocnemius musculocutanous flapThirty lower extremities of adult cadavers were used in this study. The proximal origins of the soleus were separated and the bi-pedicled gastrocnemius musculocutaneous flap was pushed distally with intact distal Achilles tendon. The sliding distance in different knee flexion degrees were measured. Clinically this modified method were used for three cases for primary evaluations.Part III: Free perforator flaps for large soft tissue defects over Achilles tendon: the anatomy and clinic studyFifteen adult cadavers were used in this study. The dissection and measurement included the diameter of the anterior and posterior tibial artery, the diameter and length of the subscapular artery, circumflex scapular artery, thoracodorsal artery, deep inferior epigastric artery, descending branch of the lateral circumflex femoral artery. The parameters were analyzed and compared. Clinically the free transfer of thoracodorsal perforator flap and anterolateral thigh perforator flap were used for 3 cases respectively. The outcomes of the two flaps were compared primarily.Results:Part I: The etiology and classifications of spoke injuriesSpoke injuries of Achilles tendon could be classified into 4 types. The outcomes are exacerbated from type I to type IV . The surgical principles are different according to the types. The main mechanism of bicycle spoke injuries involves the unscientific design of the spoke guard or no spoke guard and the trapped heel in the rear spokes. The main mechanism of motorcycle injuries involves the unscientific design of the rear spoke guard or no spoke guard, the wrong posture of the lower extremities of the backseat passenger, and the trapped heel in the spokes of an overturned motorcycle.Part II: The compound defects of Achilles tendon: the anatomy and clinic application of the modified bi-pedicled gastrocnemius musculocutaneous flapAfter resection of the proximal origins of the soleus and preservation of the intactness of the distal Achilles tendon, the sliding distance of the bi-pedicled gastrocnemius musculocutaneous flap reached (13.83±5.31)mm,(25.00±2.83)mm,(32.67±4.41)mm,and(39.50±4.85)mm respectively while the knee was flexed 0°, 30°, 60°, and 90°. A primary application of this method in 3 cases produced satisfactory outcomes.Part III: Free perforator flaps for large soft tissue defects surrounding Achilles tendon: the anatomy and clinic studyThe diameters of the major arteries of the three commonly used perforator flaps (thoracdorsal artery perforator flap, anterolateral thigh perforator flap, deep inferior epigastric artery perforator flap ) matched well with those of the anterior and posterior tibial arteries. The lengths of the major arteries were sufficient for anastomosis. They are 88.4mm , 92.7mm, 75.8mm respectively for the three flaps. Clinically the free thoracdorsal artery perforator flap (3 cases) and anterolateral thigh perforator flap (3 cases) were used for the coverage of Achilles tendon which were contaminated and exposed. The flaps finished reliable coverage with the advantages of large size, biological blood supply, and minor donor site morbidity.Conclusions:1. Spoke injuries of the heel have unique injury mechanism. The advocating of scientific spokes guards of bicycles and motorcycles probably will lower the occurrence of these injuries. The surgical protocols based on the classification could standardize the treatment and lessen the amputation rate.2. The modified bi-pedicled gastrocnemius musculocutaneous flap is anatomically feasible. This procedure is suitable for the compound Achilles tendon defects within 40 mm of adults.3. Combined with tendon reconstruction, the free thoracodorsal perforator flap and anterolateral thigh perforator flap have a good prospect for the reconstruction of large size compound defects of Achilles tendon in one stage.