Revision of Infected Total Knee Arthroplasty: Two-Stage Reimplantation Using an Antibiotic-Impregnated Static Spacer

BACKGROUND: A two-stage revision remains as the "gold standard" treatment for chronically infected total knee arthroplasties. METHODS: Forty-five septic knee prostheses were revised with a minimum follow-up of 5 years. Static antibiotic-impregnated cement spacers were used in all cases. Intravenous antibiotics according to sensitivity test of the culture were applied during patients' hospital stay. Oral antibiotics were given for another 5 weeks. Second-stage surgery was undertaken after control of infection with normal erythrocyte sedimentation rate and C-reactive protein values. Extensile techniques were used if needed and metallic augments were employed for bone loss in 32 femoral and 29 tibial revisions. RESULTS: The average interval between the first-stage resection and reimplantation was 4.4 months. Significant improvement was obtained with respect to visual analog scale pain and clinical and functional scores, and infection was eradicated in 95.6% of cases following a two-stage revision total knee arthroplasty. Radiographic evaluation showed suitable alignment without signs of mechanical loosening. CONCLUSIONS: This technique is a reasonable procedure to eradicate chronic infection in knee arthroplasty and provides proper functional and clinical results. However, it sometimes requires extensile surgical approaches that could imply arduous surgeries. Metallic augments with cementless stems available in most of the knee revision systems are a suitable alternative to handle bone deficiencies, avoiding the use of bone allografts with its complications.

Efeito da estreptoquinase e alopurinol em um modelo de reimplante de membro após isquemia quente: Estudo experimental em ratos / Streptoquinase and allopurinol effect in a limb replantation model after warm ischemia: experimental study in mice

A isquemia prolongada leva a alterações na microcirculação tecidual e à liberação de radicais livres do oxigênio, conhecidos como fenômeno de não reperfusão. Foi testado o efeito da administração de alupurinol e de estreptoquinase, em um modelo experimental, de reimplante de membro após isquemia quente em ratos. Foi realizada a amputação, com preservação de vasos e nervos do membro posterior direito, em 110 ratos. Os grupos GM1, GM2, GM3, GM4 e GM5 foram submetidos a isquemia quente de 0, 2, 4, 6 e 8 horas. As taxas de viabilidade dos membros isquêmicos, após 7 dias de avaliação, foram 100, 80, 63,6, 50 e 20, respectivamente. Os grupos GE1, GE2 e GE3 foram tratados com estreptoquinase, alopurinol e com estreptoquinase e alopurinol combinados, após isquemia de 6 horas. As taxas de viabilidade foram 66,7, 70 e 70, respectivamente. Os resultados foram analisados estatisticamente, pelo teste do Qui-quadrado, e considerados significantes quando p< 0,05. Os grupos GM1, GM2, GM3, GM4 e GM5 foram diferentes entre si, exceto os grupos GM3 e GM4. GE1, GE2 e GE3 resultaram em uma viabilidade de mem bros maior que GM4, mas não em relação ao GM3. Os resultados sugerem um aumento da viabilidade de membros isquêmicos, após 6 horas e utilização do alopurinol e estreptoquinase. A utilização do alopurinol combinado com estreptoquinase não apre- sentou efeito sinérgico.

Prolonged ischemia leads to alterations in the microcirculation and oxygen free radicals production, event called no reflow phenomenon. It was tested the effectiveness of estreptoquinase and allopurinol in a new limb replantation model after warm ischemia. Amputation with preservation of vessels and nerves of the right hind limb was proceeded in 110 rats. The model groups MG1, MG2, MG3, MG4 and MG5 were submitted to 0, 2, 4, 6 and 8 hours of warm ischemia. The viability limb rates in each model group after 7 days of evaluation were 100, 80, 63, 6, 50, 20. The experimental groups EG1, EG2 and EG3 were treated with streptoquinase, allopurinol and both drugs after 6 hours of ischemia. Limb viability rates were 66.7, 70 and 70. Results were submitted to Q-square statistical analysis and p<0.05 was considered statistically significant. MG1, MG2, MG3, MG4 and MG5 were statistically different except for MG3 and MG4. EG1 had a better limb viability rate than MG4, but not than MG3. EG2 had a better result than MG4, but not than MG2 and MG3. EG3 had a better limb viability rate than MG4, but not than MG2 and MG3. The results suggest that the administration of allopurinol and streptoquinase after 6 hours of warm ischemia may be helpful to improve limb salvage. Administration of streptoquinase and allopurinol combined did not result a synergic effect.