Calcium sulphate (CaSO₄) is a recognised form of delivery of antibiotic for the treatment of bone infection. Complications inherent in the rapid reabsorption are well recognised (predominantly that of wound breakdown and leakage). There is little data on the frequency of these complications. The purpose of this study was to quantify the incidence of wound leakage from CaSO₄ and the service impact in orthopaedic surgery.

Infective limb reconstruction cases managed with gentamicin impregnated CaSO₄ between 2004–2012 were identified. Co-morbidities and factors influencing wound leakage were recorded. Medical and wound care notes were analysed. Episodes of delayed discharge and unscheduled clinic attendance due to wound leakage were recorded.

80 patients (18 female, 62 male), with a mean age of 45 years (18–80 years, median 46 years) underwent 84 procedures utilising CaSO₄. 47 were in the tibia, 14 in the femur, 10 in the humerus. A mean of 36 mL (4–150 mL, median 22 ml, unknown in 18 cases) was used.

31 cases (37%) had post-operative wound leakage, the majority from the tibia(55%) and femur(25%). 21 cases (25%) leaked within the first week. Each 10 ml rise in CaSO₄ volume lead to a 50% rise in leakage incidence. Leak duration ranged from 4 days–10 months. The majority leaked between 1–4 months before ceasing spontaneously and without specific treatment.

14 cases (17%) required a cumulative 32 unscheduled clinic appointments for leakage. Further surgery was required for infection in 7 cases (8.3%). Delayed discharge was not clearly attributable to CaSO₄. The mode of skin closure and cultured organism did not affect leakage.

CaSO₄ has unpredictable leakage, but is present in 1/3 of patients. Volume of CaSO₄ impacts on leakage. Leakage usually self-resolves and does not clearly impact on final outcomes. The cost impact of ongoing wound care and additional clinic appointments may be substantial.