Addressing Biomechanics Matters in Treating Diabetic Foot Ulcers

Tiruveedhula et al ⁹ described a relatively simple 2-stage approach to treat forefoot diabetic forefoot ulcers and callus. A consecutive series of 112 patients (146 feet) with nonischemic forefoot ulcers were treated with percutaneous Achilles tendon lengthening and a short leg walking cast. Ninety-six percent of the ulcers healed within 10 weeks, and only 10% of ulcers recurred or did not heal. Subsequently, these 10% underwent proximal metatarsal osteotomy and all healed without recurrences and were ulcer free for 12 months.

The current initial standard of care for treating diabetic foot ulcers includes offloading, debridement of devitalized tissue, and moist wound care. Wounds that do not reduce in size by 50% by 4 weeks with standard of care are unlikely to heal. ⁸ As a result, other options for advanced wound care are recommended if standard of care is not working. In this current era of regenerative medicine, many studies promote the use of bioengineered products to heal diabetic foot ulcers that have not reduced in size by 50% at four weeks. Many of these studies are randomized prospective studies; however, the inclusion criteria often exclude the types of patients seen by “real world” providers. Tiruveedhula et al ⁹ report that 90% of the patients in this series were definitively treated with an in-office lengthening of the Achilles tendon and application of a walking cast. Although the authors did not discuss the costs of these procedure, one can only speculate that the costs to treat these patients were substantially less than patients who receive advanced wound care products such as adipose-derived stem cells, negative-pressure wound therapy, platelet-rich plasma, acellular and cellular skin substitutes, and amniotic membrane products.

The authors should be congratulated on recognizing and discussing the importance of altered biomechanics in the pathophysiology of forefoot diabetic foot ulcers. Typically, the etiology of diabetic foot ulcers is thought to be neuropathic, neuroischemic, or ischemic, but this fails to consider the importance of abnormal forefoot pressure that occurs during normal ambulation. As the authors astutely report, forefoot pressures are increased by ankle equinus, claw toes, and tendon imbalance. The authors also wisely point out the importance of the peroneus longus in causing plantar flexion of the first ray (forefoot valgus) and contracture of the posterior tibial tendon causing lateral column overload and sub–fifth metatarsal head pressure. A contracted anterior tibial tendon can also contribute to lateral column overload by potentiating a supination deformity. ³

The authors also highlight a silver lining of the COVID-19 pandemic. Access to the operating theatre was limited, so percutaneous Achilles tendon lengthening was done in the clinic. From a personal experience during the pandemic, I also learned that many of the procedures that routinely were admitted after surgery could be safely done as outpatients without increased risks in this complex patient cohort.

The treatment of patients with diabetic foot disease is extremely gratifying; however, complications are not uncommon. The authors should be commended for their excellent work, very low complication rate and their awareness of the importance of biomechanics. If you do not correct the biomechanical cause of the ulcer, recurrence is extremely high, and these rates vary widely throughout the world with a pooled recurrence rate estimate 22.1% per person-year. Recurrence rates of diabetic foot ulcers before 2002, between 2002 and 2008, and after 2008 were 22.2%, 21.9%, and 21.8%, respectively, and consequently have not changed substantially. ²

Despite excellent technique and experience, providers who treat this high-risk patient population experience adverse events. The Latin phrase caveat emptor (“let the buyer beware”) is a useful mindset to maintain. Healthy respect for comorbidities in these patients is paramount, because diabetic foot ulcers can lead to soft tissue and osseous infection, and infection can lead to both minor and major amputation. Eighty-five percent of diabetes-related amputations begin with a foot wound, and 99% of diabetic foot infections are preceded by a foot wound. Expeditious diabetic foot ulcer healing is key to preventing infection and amputation.

One of the challenges in interpreting and comparing published research on diabetic foot ulcers is that conclusions are often based on percentage of wound size reduction rather than complete healing. Tiruveedhula reported a 96% complete healing within 10 weeks. Although this was not a comparative study, the healing rates of this 2-stage approach are quite favorable when comparing this study with randomized controlled studies addressing such things as adipose-derived stem cells, negative-pressure wound therapy, platelet-rich plasma, acellular and cellular skin substitutes, and amniotic membrane products. Table 1 highlights the outcomes of recent systematic reviews reporting on the outcomes from comparative studies using advanced wound care.

Table 1.

Outcomes of Recent Systematic Reviews Reporting on the Outcomes from Comparative Studies Using Advanced Wound Care.

		Healing Rate
Author (Year)	Systematic Review	Study Group, %	Control Group, %
Elsharkawi et al 1 (2023)	Adipose-derived stem cells	84	52
Peng et al 6 (2023)	Platelet-rich plasma	76	47
Liu et al 4 (2017)	Negative-pressure wound therapy	53	36
Mohammed et al 5 (2022)	Amniotic membrane	67	30
Santema et al 7 (2016)	Skin substitutes (acellular and cellular)	41	27
Tiruveedhula et al 9 (2023)	Achilles tendon lengthening and casting	96	N/A

The importance of offloading and addressing biomechanics cannot be overemphasized in healing diabetic foot ulcers, but also in preventing recurrence. In many parts of the world, diabetic foot ulcers are treated by nonsurgeons, and surgery is not considered as part of care for these patients. Tiruveedhula et al ⁹ have made an important contribution to this field, because the technique of percutaneous Achilles tendon lengthening and casting is something that can be shared globally. As surgeons, it is our duty and responsibility to teach providers from developing countries how to do this. Healing forefoot ulcers in a timely fashion reduces amputations, no matter where in the world you practice. Some impoverished countries do not have plaster or fiberglass, and providers have created innovative ways of offloading diabetic foot ulcers that can be used with techniques as described by the authors. The authors are applauded for emphasizing the important contribution of surgery in treating diabetic foot ulcers.

Supplemental Material

sj-pdf-1-fai-10.1177_10711007231204365 – Supplemental material for Addressing Biomechanics Matters in Treating Diabetic Foot Ulcers

Supplemental material, sj-pdf-1-fai-10.1177_10711007231204365 for Addressing Biomechanics Matters in Treating Diabetic Foot Ulcers by Dane K. Wukich in Foot & Ankle International

Dane K. Wukich, MD