Exposed Tendon & Hardware After 1st MTP Fusion: Healing a Chronic Dorsal Foot Ulcer with a Borate-Based Bioactive Glass Fiber Matrix

TL;DR

A 69-year-old woman developed a chronic dorsal foot ulcer with exposed tendon and hardware following 1st MTP fusion. After hardware removal and three serial borate-based bioactive glass fiber matrix (BBGFM) applications, the wound achieved 88.9 % percent-area reduction and closure by week 18 (Podiatry Institute 1st MPJ fusion complications; Review on exposed bone/tendon coverage & NPWT).

(Dorsal foot ulcer with exposed tendon, initial visit)

Clinical problem: when dehiscence meets hardware

Post-fusion wounds with exposed tendon or hardware are notoriously difficult to salvage—motion, infection, and poor soft-tissue coverage keep them in inflammatory stasis, even with NPWT or cellular matrices (Orthopaedic review of fusion complications; NPWT overview in exposed structures).

Prior care & inflection point

Initial care with bovine and amniotic matrices plus VAC/NPWT yielded only temporary gains. Hardware removal on 1/31/25 was followed by BBGFM placement on 2/12/25 (Hardware removal rationale; WoundSource Mirragen® overview).

(Six days post BBGFM placement)

Why it may work

Borate-based glass matrices release therapeutic ions (boron, calcium, phosphate) that drive angiogenesis, fibroblast proliferation, and M1→M2 macrophage modulation, producing a regenerative micro-environment even over exposed structures (ACS Applied Bio Materials 2024 review; PMC 9012145 mechanism summary).

Outcomes

After three applications over ~9 weeks:

• Baseline volume: 9.0 cm³ → ~1.0 cm³ (88.9 % PAR) at week 18

• Serial photos confirmed granulation → epithelialization → closure by 4/14/25
  Percent-area reduction (PAR) ≥ 50 % by 4 weeks is predictive of 12-week healing (Sheehan et al., Wound Repair Regen 2003; Wounds 2020 validation study).

  

  (Full closure of dorsal foot ulcer on 4/14/25)

Interpretation

Even after multiple failed modalities, introducing BBGFM post-hardware removal aligned with a favorable healing inflection—consistent with RCT data showing improved closure using the same matrix in chronic wounds (Mirragen RCT, PMC 7348761).

Mechanism snapshot

Borate glass fibers influence the wound microenvironment by promoting neovascularization and fibroblast proliferation, helping transition chronic wounds from stasis to healing—especially valuable when tendon or hardware exposure prevents typical granulation (Comprehensive biomaterials review, Elsevier 2022).

Practical pearls for exposed-hardware wounds

1. Reset the bed first: treat infection, debride, and remove mechanical barriers (AAOS guidelines on chronic wound bed prep).

2. Plan on serial applications: repeated matrix use over weeks correlates with improved closure (BBGFM case series 2025).

3. Measure trajectory: track PAR + photo documentation (Wound measurement methods review).

4. Keep it multimodal: combine with compression/offloading—matrix is adjunctive, not a replacement (International consensus on adjuncts, 2023).

Limitations

Single-patient evidence; confounded by hardware removal and concurrent care. Nonetheless, the temporal association between BBGFM initiation and rapid granulation/closure supports further controlled study (Case-series discussion, Wounds 2024).

Bottom line:
When traditional therapies—including NPWT, amniotic membranes, and bovine matrices—fail to restore coverage over exposed tendon or hardware, borate-based bioactive glass fiber matrix (BBGFM) can serve as a regenerative bridge to closure. By releasing therapeutic ions that drive angiogenesis, fibroblast activation, and antimicrobial balance, BBGFM helps convert non-granulating, high-risk wounds into actively healing ones—even in the challenging post-fusion setting. Although this is a single-patient case, the marked 88.9 % area reduction and documented closure following hardware removal highlight the matrix’s potential as a valuable adjunct—not replacement—for meticulous debridement, infection control, and offloading in exposed-structure wound care.

References & Supporting Citations

1. Podiatry Institute. 1st Metatarsophalangeal Joint Fusion: Complications and Management. https://www.podiatryinstitute.com/pdfs/Update_2018/Chapter_07.pdf
   – Comprehensive review of 1st MPJ fusion outcomes, including dehiscence and hardware-related wound issues.

2. Lee, M. et al. (2021). Negative Pressure Wound Therapy for Exposed Bone and Tendon. Journal of Wound Care, 30(3). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7951392/
   – Discusses NPWT in managing complex wounds with exposed tendon or bone.

3. Caravaggi, C. et al. (2013). Complications Following First Metatarsophalangeal Arthrodesis. Foot & Ankle International. https://journals.sagepub.com/doi/10.1177/1071100713519772
   – Details common post-fusion wound complications and salvage strategies.

4. Pitt, A. et al. (2019). Negative Pressure Wound Therapy: Mechanisms and Applications. PubMed. https://pubmed.ncbi.nlm.nih.gov/31408036/
   – Summarizes mechanisms and clinical benefits of NPWT in chronic wounds.

5. StatPearls. Orthopedic Hardware Removal. https://www.ncbi.nlm.nih.gov/books/NBK553096/
   – Clinical rationale and technique considerations for hardware removal in non-healing postoperative wounds.

6. WoundSource. Mirragen® Advanced Wound Matrix Product Overview. https://www.woundsource.com/product/mirragen-advanced-wound-matrix
   – Manufacturer overview and clinical indications of borate-based bioactive glass fiber matrices.

7. ACS Applied Bio Materials (2024). Therapeutic Ion Release from Bioactive Glasses and Their Regenerative Role. https://pubs.acs.org/doi/full/10.1021/acsabm.4c01059
   – Mechanistic analysis of borate and silicate bioactive glasses in wound healing.

8. Li, H. et al. (2022). Bioactive Glasses in Tissue Repair and Regeneration. Elsevier: Progress in Biomaterials. https://www.sciencedirect.com/science/article/pii/S0928493122003288
   – Comprehensive review of ionic signaling and tissue regeneration mechanisms.

9. Davis, S. et al. (2020). Predictive Value of 4-Week Percent Area Reduction for Wound Healing. Wounds Journal. https://pubmed.ncbi.nlm.nih.gov/33075354/
   – Validates 4-week PAR as a predictor for wound closure.

10. Sheehan, P. et al. (2003). Percent Change in Wound Area of Diabetic Foot Ulcers Predicts Healing in a Prospective Study. Wound Repair and Regeneration. https://pubmed.ncbi.nlm.nih.gov/12631283/
    – Foundational study defining PAR as a metric for early healing response.

11. Baer, D. et al. (2020). Randomized Controlled Trial of a Resorbable Glass Fiber Matrix in Chronic Wounds (Mirragen®). PubMed Central. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7348761/
    – Clinical evidence showing higher closure rates with BBGFM compared to standard care.

12. CenterWatch Clinical Trials. Mirragen Glass Fiber Matrix for Chronic Wounds. https://www.centerwatch.com/clinical-trials/listings/274210/
    – Current and ongoing BBGFM clinical trials.

13. Leaper, D. et al. (2018). Consensus Guidelines for Debridement of Chronic Wounds. Plastic and Reconstructive Surgery. https://journals.lww.com/plasreconsurg/Fulltext/2018/06000/Consensus_Guidelines_for_Debridement_of_Chronic.13.aspx
    – Consensus guidance on debridement prior to biologic/advanced matrix use.

14. Rajbhandari, S. et al. (2021). Quantitative Wound Measurement: Tools and Techniques. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878672/
    – Describes image-based wound measurement methods including PAR.

15. Wounds International (2023). International Consensus: Wound-Healing Adjuncts and Their Integration with SOC. https://www.woundsinternational.com/resources/details/international-consensus-wound-healing-adjuncts/
    – Guidance for integrating adjunctive products like BBGFM within SOC.

16. Cambridge Media (2024). Bioactive Glass Wound Matrix: Early Healing Signals in Chronic Wounds. Wound Practice & Research. https://journals.cambridgemedia.com.au/wpr/volume-32-number-3/bioactive-glass-wound-matrix-early-healing-signals-chronic-wounds
    – Case-series support for bioactive glass matrices as effective adjuncts in complex wounds.