Bony Defects of the Foot Lead to High Rates of Transfer Lesion Development: Soft Tissue Reconstruction is Not Enough in the Chronic Wound Population
Priya Bhardwaj, MS1, Elizabeth G. Zolper, BS2, Jenna C. Bekeny, BA2, Andrew I. Abadeer, MD, M. Eng2, Kenneth L. Fan, MD2, Karen K. Evans, MD2.
1Georgetown University School of Medicine, Washington, DC, USA, 2Department of Plastic and Reconstructive Surgery, MedStar Georgetown University Hospital, Washington, DC, USA.
BACKGROUND: Bony resection is often necessary prior to soft tissue reconstruction in chronic wound populations. While transmetatarsal amputation is argued to be the most functional approach when extensive bony resection is required, preservation of the first two rays may improve load-bearing. However, altering the metatarsal parabola risks transfer lesion development. The aim of this study was to investigate the risks of ulcer recurrence and transfer lesion development in microsurgical soft tissue reconstruction with underlying bony defects.
METHODS: A retrospective review of lower extremity free tissue transfer (FTT) for chronic wounds with underlying bony defects of the foot at our institution from 2011-2019 was performed. Data collected included demographics, comorbidities, wound locations, and FTT characteristics. Outcomes of interest were ulcer recurrence and transfer lesion development post-FTT. Multivariate logistic regression was used to produce adjusted odds ratios for transfer lesion development using a backwards model.
RESULTS: We identified 64 FTT procedures performed for lower extremity salvage with bony defects. Mean age was 55.9 years old (SD 11.8). Mean Charlson Comorbidity Index was 4.1 (SD 2.0). Common comorbidities included: diabetes (76.6%) and osteomyelitis (68.8%). The majority of bony defects involved the tripod of the foot (79.7%) with resection of a portion of the first metatarsal (46.9%), fifth metatarsal (51.6%) or calcaneus (21.9%). Wounds developed post-FTT in 70.3%. The original ulcer recurred in 39.1% while transfer lesions developed in 43.8%.
Median time to transfer lesion development was 3.7 months. On bivariate analysis, neither tripod(p=0.104), first metatarsal(p=0.053), nor fifth metatarsal(p=0.198) defects had significant relationships with increased odds of transfer lesion development. Calcaneal defects also did not exhibit a significant relationship with transfer lesion development(p=0.939). Diabetes(p=0.043) and plantar weightbearing defect(p=0.045) exhibited significant relationships with transfer lesion development. On multivariate analysis, first metatarsal (OR 7.2, 95% CI 1.6-31.8) and plantar weightbearing defects (OR 4.6, 95% CI 1.1-19.1) were independently associated with increased odds of transfer lesion development. Fasciocutaneous flap type was significant for decreased odds of transfer lesions (OR 0.15, 95% CI 0.03-0.66). Diabetes was no longer a significant predictor for transfer lesion development.
CONCLUSIONS: Defects of the load-bearing tripod, particularly the first and fifth metatarsal, significantly increase risk of transfer lesion development after FTT. While solely soft tissue reconstruction with FTT achieves success in the short-term, transfer lesions occur at high rates following initial healing. Use of composite osteocutaneous flaps may be valuable to decrease transfer lesion risk by achieving both bony and soft tissue reconstruction.
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