Use of Native Collagen Matrix with PHMB Graft and Novel Free Micro-Granulation Tissue Grafting to Manage Dehiscence of Total Knee Arthroplasty and Patellar Tendon Rupture

Introduction: The patient is a 69 year old male who underwent multiple right total knee arthroplasties for a traumatic knee injury secondary to a fall 13 years ago. Following the most recent surgery, the patient suffered multiple infections leading to dehiscence of the incision and patellar tendon rupture. The patient presented to plastic surgery with an open wound of the knee involving exposed patellar tendon repair. Preferred management for this type of wound is a medial gastrocnemius flap. Given the patient’s history of multiple surgeries the team agreed the best option to manage the wound would be secondary closure. The team accepted that the patient would have significant loss of range of motion, though it was felt the morbidity and mortality of an AKA justified the decision.

Methods: The patient in this single case study was managed weekly with debridement and subsequent staged free micro-granulation tissue transfer to cover exposed tendon. The transferred granulation was protected by followed application of a five-layer native collagen matrix with polyhexamethylene biguanide (PHMB) antimicrobial barrier (PCMP-XT)(a) followed by application of negative pressure therapy (NPWT).

Results: The patient underwent a total of 3 micro-granulation tissue transfers to cover exposed tendon followed by application of PCMP-XT and NPWT. Weekly evaluation revealed 100% take of the granulation tissue grafted to each area of exposed tendon to achieve complete granulation of the wound.

Discussion: A single case series is found in the literature demonstrating the use of pedicle granulation flaps, to our knowledge this is the first reported case of free micro-granulation tissue grafting.1 Inosculation and subsequent successful take of the micro-granulation tissue graft is two-fold. It is dependent upon the collagen matrix to manage bioburden, create a scaffold to support the tissue transfer, and facilitate proliferation of the granulation tissue. NPWT was used to bolster the collagen matrix and tissue graft while drawing wound fluid to oxygenate the grafts.