Adjuvant antibiotic calcium sulphate bio composites for implant related bone sepsis in foot and ankle - a single stage approach

H. Mohammad, T. Tabain, A. Pillai

Aim: We describe a case series using adjuvant calcium sulphate bio composites with antibiotics in treating infected metalwork in the foot and ankle.

Method: 11 patients aged 22-81 (9 males, 2 females) were treated with clinical evidence of infected limb metal work from previous orthopaedic surgery. Metal work removal with intra osseous application of either cerement in 8 cases (10-20ml including 175mg- 350mg gentamycin) or stimulan in 3 cases (5-12ml including 1g vancomycin) into the site was performed. Supplemental systemic antibiotic therapy (oral/intravenous) was instituted based on intraoperative tissue culture and sensitivity.

Results: 7 patients had infected ankle metalwork, 2 had infected foot metalwork and 2 had infected external fixators. Metal work was removed in all cases. Mean pre operative CRP was 25.4 mg/l (range 1-137mg/l). Mean postoperative CRP at 1 week was 15.4mg/l (range 2-36mg/l) and at 1 month was 16.1mg/l (range 2-63mg/l). Mean pre op WCC was 8.5x10⁹ (range 6.2-10.6x10⁹). Mean post op WCC at 1 week was 8.8x10⁹ (range 5.1-12.7 x10⁹) and 1 month was 7.1x10⁹ (range 3.7-10.4 x10⁹). Organisms cultured included enterobacter, staphylococcus species, stenotrophomonas, acinetobacter, group B streptococcus, enterococcus, escherichia coli, pseudomonas, morganella morganii and finegoldia magna. Infection eradication as a single stage procedure with primary would closure and healing was achieved in 10 out of 11 cases (90.9 %). No additional procedures were required in these cases.

Conclusions: Our results support the use of a calcium sulphate bio composite with antibiotic as an adjuvant for effective local infection control in cases with implant related bone sepsis. The technique is well tolerated with no systemic or local side effects. Our results show that a single stage implant removal, debridement and local antibiotic delivery can achieve over 90% success rates. We theorise that it could minimise the need for prolonged systemic antibiotic therapy in such cases.