Antibiotic penetration into the infected knee. A rabbit experiment

Intra-articular Gentamicin-loaded PLA Microparticle Injection for the Treatment of Septic Arthritis in Rabbits

BACKGROUND

Because local delivery of drugs induces high concentrations, it could be helpful to apply these delivery systems to the treatment of septic arthritis by antibiotics. Thus, a gentamicin-loaded polymer was tested in a rabbit model of Staphylococcus aureus septic arthritis.

METHODS

Thirty New Zealand rabbits were split into five groups: A: infection only; B: infection and systemic gentamicin treatment; C: infection and unloaded polymer and systemic gentamicin treatment; D: infection and gentamicin-loaded polymer only; and E: no infection and unloaded polymer. After inducing nonlethal septic arthritis in the knee joint by injecting 10 colony-forming units (CFUs) of a strain of methicillin-sensitive S aureus in groups A, B, C, and D, rabbits were housed for 15 days, and then the joint capsules were removed and the remaining bacteria were counted. Bacterial load was expressed in CFUs per gram of synovial tissue. In group E, capsules were removed, and a pathologic examination was done.

RESULTS

At day 15, the bacterial load was 6 × 10, 2 × 10, 1.8 × 10, and 7 × 10 CFU/g of tissue for groups A, B, C, and D, respectively. Compared with the mean of groups A, B, and C, the bacterial load of group D was 4.94 units of log10 CFU/g lower than that of these groups. The bacterial load of group D was statistically significantly lower than that of the other three groups. Noticeably, two animals of group D had a nil bacterial count. In group E animals, a minimal foreign body reaction was observed around the polymer.

DISCUSSION

Gentamicin-containing microparticles were more efficient in reducing bacterial load than systemic injections of gentamicin and thus have an interesting role to play in the treatment of human arthritis. However, inserting microparticles in joints is not easy, and hydrogels might be a good alternative approach.

[Stage-dependent arthroscopic treatment of knee joint infections]

OBJECTIVE

The goal is early diagnostic arthroscopy with irrigation and, if needed, debridement of all 6 recesses of the infected knee joint to quickly gain control of the infection and a satisfactory functional outcome.

INDICATIONS

Arthroscopic irrigation without delay is indicated even if a knee joint infection is only suspected.

CONTRAINDICATIONS

No existing contraindications.

SURGICAL TECHNIQUE

Arthroscopic irrigation of the knee with stage-related debridement. Particularly irrigation and debridement of the two dorsal recesses. In stage IV according to Gächter, open synovectomy and radical debridement is recommended.

POSTOPERATIVE MANAGEMENT

In case of persistent infection, early revision. After removement of drainages mobilisation with continous passive motion. Antibiotic therapy is necessary even after the infection has been treated.

RESULTS

Arthroscopic irrigation with stage-related debridment of all 6 recesses in combination with antibiotic therapy is the standard procedure for knee joint infections when there is no arthroplasty. Open surgery with debridement of infected bone tissue is indicated in patients with stage IV according to Gächter. Decisive for good results is an early intervention.

Treatment of septic knee arthritis: comparison of arthroscopic debridement alone or combined with continuous closed irrigation-suction system

BACKGROUND

Arthroscopic debridement has been widely adapted as initial treatment for septic knee arthritis. Although isolated cases of arthroscopic debridement combined with irrigation-suction systems have been reported, a comparison of two techniques has not been performed, to our knowledge. The purpose of this study was to compare the two methods of treatment.

METHODS

From January 1996 to December 2008, 39 patients with 39 septic knee arthritis treated in our institution were retrospectively analyzed. Nineteen knees were initially treated with arthroscopic debridement alone (group I), and 20 knees were initially treated with arthroscopic debridement combined with continuous closed irrigation-suction system (group II). The clinical presentation, laboratory and microbiologic findings, hospital course, and clinical outcomes were compared between the two groups.

RESULTS

The mean delay between the onset of the symptoms and treatment had a significant effect on the clinical outcomes. When the comparison included all the patients in the series, no significant difference between the two groups was found with regard to the number of operation procedures required or the length of the hospital stay. However, when the comparison was separated from the initial stage of infection, it was found that in stage II infection, patients had fewer reoperations and in stages II and III infection, a shorter hospital stay in group II than in group I (p < 0.05). There was no significant difference in the functional results between the two groups.

CONCLUSIONS

The early diagnosis and aggressive initiation of treatment carried the success of therapy in septic knee arthritis. Arthroscopic debridement combined with continuous closed irrigation-suction system is an effective treatment for patients with septic knee arthritis; these patients had fewer operations and a shorter hospital stay than did patients who had received arthroscopic debridement alone.

Septic arthritis of the knee: presentation of a novel irrigation-suction system tested in a cadaver study

Background

The established treatment for bacterial arthritis of the knee joint is arthroscopic surgery with irrigation and debridement. The aim of this article is to summarize the relevant data in treating bacterial arthritis of the knee joint, and based on these findings to present a novel irrigation suction system, tested in a cadaver study, as an additional tool in the postoperative treatment phase of arthroscopic surgery for knee joint infections.

Method

The novel automated irrigation-suction system presented here was compared to conventional continuous suction irrigation in a total of six knee joints. All knee joints were filled with 80 ml methylene blue stain and rinsed by two different methods. Fluid specimens were taken after ten and twenty minutes to be compared by photometric extinction measurement at a wave length of 500 nm.

Results

After ten minutes, the average extinction was e_1C = 0.8 for the continuous suction irrigation and e_1N = 0.4 for the novel irrigation-suction system. After twenty minutes, we recorded an average extinction of e_2C = 0.3 for continuous suction irrigation and e_2N = 0.001 for the novel irrigation-suction system. The students t-test revealed superior results after ten and twenty minutes of washing out the knee joints with a p < 0.001 for the novel irrigation-suction system.

Conclusion

A novel irrigation-suction system may be an effective tool for postoperative knee joint irrigation in arthroscopic therapy for bacterial arthritis of the knee. Further animal studies are needed to verify the effects in vivo.

[Acute joint infection--diagnosis and treatment]

The acute joint infection is a rare condition; the delayed diagnosis may lead to significant joint destruction. Diagnostic tools are the c-reactive protein and joint aspiration. Today arthroscopic treatment options are suitable tools for the treatment of such conditions. Arthroscopic lavage and debridement with additional systemic antibiotic treatment proofed to be very effective in an infected joint. If there are continuous signs of infection even with antibiotic treatment, rearthroscopy within few days is indicated. The number of rearthroscopies is related to the initial stage of the infection. With a shaver thorough debridement of all necrotic tissue as well as resection of adhesions is performed without complete resection of the intact and noninfected synovial membrane. The use of intraarticular resorbable antibiotic fleece is possible, but not generally recommended. Suction irrigation systems are only rarely indicated. If there is bony involvement, open arthrotomy still is the golden standard.

Treatment of infectious arthritis and osteomyelitis

Infectious arthritis and osteomyelitis are commonly encountered diseases of the skeletal system that can result in premature loss of an affected animal from the herd. Selection of the best possible treatment approach for an individual animal requires a solid understanding of the pathophysiologic processes involved in the infection of bone or joint; recognition of the unique aspects of the anatomy, physiology, behavior, management, and economics of the species involved; and a broad grasp of the availability and role of various therapeutic options. By recognizing the importance of all three of these areas, a clinician not only will be able to make realistic and effective judgments about care of commonly encountered cases today but also will have a sufficient basis for rational variations in therapy as pharmacologic options expand and environmental or economic pressures change.

Antibiotic treatment insufficient for established septic arthritis. Staphylococcus aureus experiments in rabbits

We treated septic arthritis of the knee in 38 rabbits with cloxacillin i.m. once and twice daily combined with probenecid for 7 or 21 days, respectively, or with only cloxacillin i.m. thrice daily for 7 days. The animals were killed weekly in groups up to 5 weeks after inoculation. Aspirated cultures obtained after 4 days of treatment were always negative. Histologic specimens revealed progressive joint destruction, but at a slower rate after frequent treatment independent of the period. We concluded that antibiotic therapy alone could not prevent destruction of articular cartilage once bacterial arthritis was established.