Per Riegels-Nielsen

Rabbit model of septic arthritis

Eighty-five rabbits were injected in one knee with Staphylococcus aureus in order to study the time-related changes in untreated septic arthritis up to 3 months. In the synovial membrane a severe release of lysosomal enzymes was observed. The activity was mainly located in and around lining cells and leucocytes in the pannus demonstrating increasing destructive characteristics. This resulted in marginal erosion and undermining of the cartilage border visible from Day 5 continuing gradually to total joint destruction after 5 weeks. The glycosaminoglycan depletion was observed at the surface of the cartilage at Day 2 and was total after 2 weeks. Our infection model should permit comparison of different therapeutic measures.

Osteochondritis dissecans of the femoral condyle treated with periosteal transplantation: Poor outcome in 14 patients followed for 6–9 years

We evaluated 14 consecutive periosteal transplantations to treat osteochondritis dissecans lesions of the femoral condyle. 1 year postoperatively, 9 knees were pain-free, but with 6-9 years follow-up, only 2 knees were pain-free. Formation of hyaline-like cartilage, assessed in 12 knees, was documented in 1 patients and assessed as possible in 1 more, but in 10 patients the tissue formed in the defects was not or probably not hyaline cartilage. 6 knees had developed arthrosis.

Fournier's gangrene: 5 patients treated with hyperbaric oxygen.

The classic syndrome of Fourniers gangrene was observed in 5 men with involvement of the external genitals and lower abdominal wall. Mixed flora of anaerobic and aerobic microorganisms were grown, and extensive necrosis of the skin and subcutaneous gas were present in all patients. Soon after hospitalization all 5 patients were treated by excision of all necrotic and undermined tissue, intravenous broad-spectrum antibiotics and hyperbaric oxygen administered at 3 atmospheres of pressure. One patient died of septic shock without any response to the therapy. The infection subsided shortly after the hyperbaric oxygen was instituted in the remaining 4 patients, who were cured. It is proposed that the treatment of Fourniers gangrene should be limited to centers capable of administering hyperbaric oxygen therapy. Our series does not prove that hyperbaric oxygenation is necessary for successful treatment but evidence suggests a beneficial effect of such therapy for nonclostridial gas gangrene.

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.

Boneloc® cemented total hip prostheses: Loosening in 28/43 cases after 3-38 months

We report our early results with 43 total hip prostheses (25 Charnley and 18 LMT) inserted during 1991 with Boneloc cement. The indication was primary arthrosis (38) and rheumatoid arthritis (5). After 18 (3-38) months, 28 stems were loose and 18 hips have been revised 1-4 years after primary surgery.

Collagen with gentamicin for prophylaxis of postoperative infection. Staphylococcus aureus osteomyelitis studied in rabbits.

In 34 rabbits, both tibiae were inoculated with Staphylococcus aureus. 14 legs received no treatment and served as controls. In 12 legs, the wound was treated with pure collagen and in 18 legs, collagen with gentamicin (Gentacoll) in a dose of 10 mg/kg body weight was applied to the wound before closure. Postoperatively 12 received 10 mg/kg body weight gentamicin intravenously and no local treatment. The animals were killed 7 days after inoculation and evaluated macroscopically and microbiologically for infection. 6 rabbits (12 legs) were used for pharmacokinetic studies only and they were killed after 2, 4, and 18 hours, respectively. 11/14 untreated legs developed a macroscopically acute osteomyelitis. No infection was found in the 18 legs treated with Gentacoll and 1/12 treated with gentamicin systemically had growth of the inoculated bacteria in tissue biopsies. The concentrations of gentamicin in the serum as well as locally reached peak values were well above the MIC value in all groups, with a maximum after 1-2 hours. No gentamicin could be detected after 18 hours, independently of the mode of administration.

Antibiotic penetration into the infected knee: A rabbit experiment

We investigated the diffusion of penicillin-G, cloxacillin, clindamycin, and netilmicin into synovial fluid and membrane in rabbits. Purulent arthritis was induced in the right knee of each rabbit by inoculation of Staphylococcus aureus phage type 3C, whereas sterile saline was injected into the left knee to serve as a control. Two days later, concentrations of antibiotics were determined in serum, synovial fluid, and membrane after an intramuscular single dose. All four drugs diffused readily into infected joints, whereas the corresponding concentrations in the normal joints were 2-3 times lower. Clindamycin showed the highest intraarticular penetration, cloxacillin the lowest. The lower penetration of cloxacillin corresponded to its higher protein binding in rabbit serum. Considering the sufficient local concentrations achieved, parenteral treatment obviates the need for local instillation of these antibiotics.

FIBRIN FIXATION OF OSTEOCHONDRAL TALAR FRACTURE

Six osteochondral talar fractures in 5 patients were fixed with fibrin sealant. All the lesions healed uneventfully. After 1 year, 3 of the 4 athletes in the study had resumed their sports activities at the same level as prior to the accident.

Synovectomy for septic arthritis: Early versus late synovectomy studied in the rabbit knee

Thirty rabbits with established unilateral septic arthritis of the knee after inoculation with Staphylococcus aureus received cloxacillin 50 mg/kg x 2 i.m. and probenecid 250 mg x 1 p.o. from Day 3 to 21. In 26 knees, synovectomy was performed 3, 5, and 7 days after the inoculation, and four knees were not operated on. Further, synovectomy was performed in eight noninfected knees. The rabbits were killed 3 or 7 weeks after the operation, and the specimens were examined macroscopically and microscopically. All the cultures taken postoperatively and at killing were negative. Infected knees synovectomized on Day 3 differed, although marginally, 3 weeks postoperatively from the operated on, uninfected group; a minor loss of cartilage cellularity and glycosaminoglycans was observed, but there were no changes indicating arthrosis. At 7 weeks postoperatively, this difference was more pronounced. If synovectomy was performed at a later stage, increased destruction was observed: after 7 days of infection, all the knees presented cloning and vascular crossing of the tidemark, indicating arthrosis, which did not differ from those knees treated with only antibiotics. We conclude that synovectomy performed early in the course of infection may stop the destructive influence of enzymes and of the synovial membrane leading to irreversible changes in the cartilage.

Septic arthritis of the knee: Five cases treated with synovectomy

Five cases of suppurative non-gonococcal arthritis of the knee were treated with synovectomy 1-2 weeks after the diagnoses were confirmed. Indications for operation were persistent fever and continuous effusion, in spite of adequate antibiotic treatment and serial needle aspirations. The infection subsided in all cases. At follow-up, 2 years after operation, one patient had died of other disease, and there had been no recurrences among the remaining four. One patient had disabling pain on weight-bearing and considerable restriction of knee motion with 2-3 mm radiographic narrowing of the joint space. Three knees were painless on normal motion, but in two case changes resembling osteochondritis were found radiographically.