Tendo-Achilles Lengthening: Friend Or Foe In The Diabetic Foot?
It is important to recall the previous discussion about the soft tissue changes that occur in the diabetic Achilles tendon. The Achilles tendon is already compromised and surgery further compromises this tendon. Researchers have demonstrated that the Achilles tendon in the patient with diabetes has an altered healing cascade.42 Indeed, we are surgically incising the Achilles tendon in an already unstable environment.
Also bear in mind that it may be necessary to perform a TAL repeatedly in the future. Recurrence of an equinus deformity should not be a surprise considering that a TAL does not change the intrinsic properties of a diseased Achilles tendon. Repeated surgeries would certainly have an additive deleterious effect on an already damaged Achilles tendon, further compromising this area.
Let us revisit the prospective, randomized paper published by Mueller, et al.40 They report no difference in the number of healed ulcerations or time to healing between the TAL plus TCC group versus the TCC alone group. However, they do report a lower recurrence rate with the TAL group at seven months (15 percent) and at 2.1 years (38 percent) versus the TCC alone group at seven months (59 percent) and at 2.1 years (81 percent). Additionally, the recurrence of an ulcer happened sooner in the TCC alone group.
Interestingly, the authors report that the peak plantar pressures and the peak torque returned to baseline levels at seven months in the TAL group despite the fact that the increase in ankle joint dorsiflexion remained at the immediate postoperative levels. This appears contradictory. Why do the recurrence rates remain relatively low at seven months and 2.1 years in the TAL group despite the fact that the peak plantar pressures reverted to baseline levels? The implication is that an increase in dorsiflexion available at the ankle joint provided by the TAL is not the pivotal predictor of ulcer recurrence.
An equinus deformity certainly plays a role in the development and chronicity of diabetic wounds. However, the exact mechanism of how this occurs remains unclear at this time. The TAL continues to be a popular adjunctive procedure in the treatment of equinus. There is ample evidence to support its use in this capacity. However, a TAL is not a panacea. Podiatric surgeons may be able to improve overall outcomes as long as they employ this procedure judiciously with careful consideration for the needs of the patient.