Bacterial Septic Arthritis of the Adult Native Knee Joint

Abstract

» Acute bacterial septic arthritis of the knee is an orthopaedic emergency and, if left untreated, can result in substantial joint degradation.» Important risk factors for development of septic arthritis include age of >60 years, recent bacteremia, diabetes, cancer, cirrhosis, renal disease, drug or alcohol abuse, a history of corticosteroid injection, a recent injury or surgical procedure, a prosthetic joint, and a history of rheumatoid arthritis.» The diagnosis is primarily based on history and clinical presentation of a red, warm, swollen, and painful joint with limited range of motion. Laboratory values and inflammatory markers from serum and joint fluid may serve as adjuncts when there is clinical suspicion of septic arthritis.» The initial and general antibiotic regimen should cover methicillin-resistant Staphylococcus aureus and gram-negative and gram-positive organisms. The antibiotic regimen should be specified following the culture results of the infected joint.» Operative management involves either arthrotomy or arthroscopy of the knee with thorough irrigation and debridement of all infected tissue. The Gächter classification is useful in establishing a prognosis or in determining the need for an extensive debridement.

Articulating vs Static Spacers for Native Knee Infection in the Setting of Degenerative Joint Disease

“…Treatment of advanced knee arthritis in the setting of infection is a clinical challenge. The mainstays of treatment for infection in the nonarthritic knee (surgical debridement, lavage, and intravenous antibiotics) do not sufficiently address any resulting cartilage damage or deformity [ [22] , [23] , [24] ]. Although this situation is rare compared to the frequency of PJI, it is important to optimize treatment for these patients, as patients with a history of infection about the knee are often more likely to develop PJI after primary TKA, especially if infectious treatment history information is limited [ [7] , [8] , [9] , 25 , 26 ].…”

Novel therapeutic interventions towards improved management of septic arthritis

“…The synovial membrane has a complex architecture with dense vascularity but the vessels of the synovial intima do not have a limiting basement membrane. This allows passage of large molecules such as hyaluronic acid across the basement membrane essential to lubricate this articular cartilage [ 9 , 13 , 14 , 45 ]. But, this also enables the constant contact with blood or lymph which facilitates hematogenous entry of bacteria or phagocytes carrying bacteria to enter the synovium.…”

“…This inflammatory reaction mounted by the host is protective and along with antibiotic therapy may help to contain the spread of infection further. But, if in case the infection is not cleared, there continues an ongoing battle of the host mounted an immune response against bacteria and the immune system exacerbates rather than ameliorates the outcome of septic arthritis [ 2 , 13 , 21 , 77 ]. Soon, the T-cells also start to enter the joint cavity and get activated upon antigen presentation supported by host antigen-presenting cells (APC’s).…”

“…As the intra-articular pressure rises, the synovial vasculature may get compressed with thrombosis and further permanent damage to the articular cartilage impeding the blood and oxygen supply as well. This may extend to the articulating bone resulting in serious damage to bone growth, especially in children, and causing permanent cartilage erosion [ 13 , 43 , 80 ]. A schematic illustration of the pathophysiology and damage involved is presented in Fig.…”

“…However, it may present itself as poly-articular as well (~22% of cases) [ 8 – 10 ]. Old age, diabetes mellitus, cirrhosis, renal disease, rheumatoid arthritis, osteomyelitis, prosthetic joint, recent joint surgery, concurrent skin infection, intravenous drug use are the possible risk factors [ 9 , 11 – 13 ]. Looking at the incidence rates, SA exhibits an annual incidence of six to ten cases per 100,000 patients per year and an associated mortality rate as high as 10-15% [ 4 , 14 – 19 ].…”