Abstract
Aim
A number of orthopaedic strategies have been described for limb salvage following periprosethic joint infection (PJI). However, this is often only possible with concomitant soft tissue reconstruction in the form of flap coverage. The purpose of this study was to determine the long-term clinical outcome of patients who underwent pedicled gastrocnemius flap coverage as part of their treatment for knee PJI.
Method
We performed a retrospective review of all patients undergoing gastrocnemius muscle transfer with split thickness skin grafting as part of their treatment for knee PJI at a tertiary referral centre between 1994 and 2015. Data recorded included patient characteristics, orthopaedic procedure, microbiology result and antimicrobial management. Outcome measures included flap failure, infection recurrence, amputation, functional outcome (Oxford knee score; OKS) and mortality.
Results
In total, 115 consecutive patients (39% female) with a mean age of 74.4 years (range 44–100) were followed up for an average of 5.5 years (range 119 days – 19.7 years). There were no reported cases of flap failure. Gastrocnemius flaps were most commonly performed at the time of the first stage of a two-stage revision (41%), or during debridement and implant retention (DAIR) (27%). 10% were performed at the second stage of a two-stage procedure and 4% were performed during a single stage revision. Of 96 positive deep specimen cultures, 43 (45%) showed mixed growth and 47 (49%) grew coagulase-negative staphylococcus (with or without other microorganisms). The infection recurrence rate was 32%. Limb salvage was achieved in 88% of cases. 12% of patients required life-long suppressive antibiotic therapy. 55 knees were followed up for five years or more, with a survival (not deceased, not amputated) of 64%. 37 knees were followed up for 10 years or more, with a survival of 32%. In living patients who did not have an amputation, the mean OKS was 25.8 (n=36; range 7–47).
Conclusion
This study represents the largest series to date of infected knee prostheses treated with gastrocnemius flap coverage. A multidisciplinary approach to complex PJI surgery is recommended, involving infectious disease physicians and the orthoplastic team. We also recommend a low threshold for requesting plastic surgery input. In our experience, this technique is safe, with no flap failure, and has enabled limb salvage for the majority (88%) of patients with infected knee prostheses and insufficient soft tissue envelope.
