Observational and retrospective comparison of incidence or prevalence of all risk factors described in the literature. These factors have been classified according to the period of risk in: epidemiologic; pre, intra and postoperative; and distant infections.
Pearson was used for comparison of qualitative variables and ANOVA for quantitative ones.
Epidemiologic characteristics: female gender, post-traumatic osteoarthritis (17% vs 3%). On the contrary, primary osteoarthritis is a “protective” factor. Preoperative conditions: previous surgery in the same hip (60% vs 6%), obesity (BMI>
30) (9% vs 1%), chronic therapy with glucocorticoids (13% vs 0%), immunosuppressive treatments, chronic liver diseases (20% vs 2%), alcohol addiction (13% vs 0%) and intravenous drug abuse. Patients in this case-control did not present a significant difference in the prevalence of diabetes (a recognised risk factor for spine and knee surgery) or rheumatoid arthritis. Intraoperative facts: a prolonged surgical time is the only significant risk factor (133 min vs 98 min), but differences were not found in the amount of bleeding, need for transfusion or intraoperative fractures. Postoperative events: secretion of the wound longer than 10 days (46% vs 8%), palpable deep haematoma (27% vs 1%), dislocation of the prosthesis (40% vs 6%), and need for new surgery in the hip (21% vs 1%). Distant infections (risk for haematogenous seeding): deep cutaneous (30% vs 8%), upper and lower urinary tract (36% vs 2%), pneumonias and bronchopneumonias (23% vs 5%), and diverse abdominal focus (14% vs 3%). On the contrary, significant differences were not found in the prevalence of severe oral or dental infections.
to control and minimize these risk factors when present when this is not possible not possible, to implement additional prophylactic measures.
Cultures were polymicrobial in 22 cases and by Gram-positive in 55 (80.9%). Highly-resistant organisms: methicillin-resistant Staphylococcus (36 patients) and ESBL-producing Enterobacteriaceae (2 patients). “Problematic-treatment”: Enterococcus (6 patients), Pseudomonas (3 patients), non-fermenting Gram-negative (2), moulds (1). Oral antibiotic selection: according to bacterial sensitivity, biofilm and intracellular effectiveness. Protocolized surgery: two-stage exchange. Average follow-up: 4.7+/−2.7 years (1–11). Healing of infection is diagnosed if absence of clinical, serological and radiological signs of infection during the whole follow-up. Orthopaedic outcome is evaluated by HHS for hips and by KSCRS for knees.
Healing of infection: 59/68 patients (86.8%), 32/37 hips (86.5%) and 27/31 knees (87.1%). Infection not healed: 7/68 cases (10.3%) (4/37 hips, 3/31 knees) (5 by highly-resistant and 1 by “problematic-treatment” bacteria). There are no differences between hips and knees (p=0.55).
Statistically significant differences are not found when comparing subgroups according to Gram stain (p=0.43), multiple vs single bacteria (p=0.47 infective, p=0.71 orthopaedic), highly-resistant bacteria (p=0.2 infective, p=0.1/0.5 orthopaedic), or “problematic-treatment” (p=0.68).
A strong statistical correlation appears between infective and orthopedic results after late arthroplasty infections. With the number of cases presented significant differences in infective or in orthopaedic results are not found when comparing single vs. polymicrobial, gram-negative vs. gram-positive, high vs. low antimicrobial resistance and “problematic-treatment” infections.
