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Septic Arthritis After Arthroscopic Anterior Cruciate Ligament Reconstruction: A Retrospective Analysis of Incidence, Presentation, Treatment, and Cause

PURPOSE The purpose of this report is to summarize our experience in the diagnosis and management of septic arthritis after anterior cruciate ligament (ACL) reconstruction. METHODS A retrospective review was conducted of all the arthroscopic ACL reconstructions performed at our institution between 1997 and 2007. Postoperative septic arthritis occurred in 21 of 4,068 patients. The incidence, cause, presentation, laboratory results, and treatment of all infected patients were analyzed. RESULTS The incidence of septic arthritis after ACL reconstruction was 0.52%. The most common symptoms of the infected patients were fever, swelling, severe pain, tenderness, and restricted motion. The erythrocyte sedimentation rate, C-reactive protein level, and fibrinogen level were markedly elevated. Microbiology showed that coagulase-negative Staphylococcus was the most common bacterium. Both conservative and operative treatments were effective, and no patient had the ACL graft removed. However, the conservative group had a longer recovery time and duration of intravenous antibiotic therapy. CONCLUSIONS Septic arthritis after arthroscopic ACL reconstruction is a rare but potentially devastating complication. The correct diagnosis relies on clinical evaluation, laboratory tests, synovial fluid analysis, and bacterial culture. With early diagnosis and prompt treatment, the infection can be successfully eradicated. Our proposed treatment protocol is arthroscopic debridement and irrigation as quickly as possible, with retention of the ACL graft when it is still functional. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Analysis of different kinds of cyclops lesions with or without extension loss.

PURPOSE The purpose of this study was to retrospectively evaluate patients after anterior cruciate ligament (ACL) reconstruction in whom a cyclops lesion developed to seek the etiologic factors. METHODS From 1999 to 2005, we observed 48 cases of cyclops lesions in 311 cases arthroscopically while removing the internal fixation devices after ACL reconstruction. Before removing the hardware, the function of the knee was evaluated through symptoms, signs, radiography, and KT-2000 measurement (MEDmetric, San Diego, CA) in 311 cases. Histologic examination was performed on some of the resected lesions. RESULTS Of the 311 patients, 45 were found to have nodular formations in the anterior part of the knee; this caused extension loss in 6 patients. Extension loss occurred at 2 to 3 months after ACL reconstruction. Histologic results were available in 18 patients (6 complained of a loss of extension and 12 were asymptomatic). Microscopic examination of the resected fibrous nodules showed disorganized fibrous connective tissue. We found that 8 nodules (4 with extension loss and 4 without extension loss) contained chondroid tissues, but we did not find osseous tissue in the nodules. The histologic appearance was similar to hypertrophic, degenerative granulation tissue. CONCLUSIONS Among 311 second-look arthroscopies after ACL reconstruction, 45 cyclops lesions were found with a typical histology indicating an inflammatory proliferation with disorganized fibrous tissue, with some having chondroid tissue. Clinically, 10 patients had not returned to sporting activities: 6 of 6 who had extension loss and 4 of 39 who had full range of motion. All 6 patients with extension loss had full motion after resection of the cyclops lesion. LEVEL OF EVIDENCE Level IV, therapeutic case series.

The protective effect of tetramethylpyrazine on cartilage explants and chondrocytes

AIMS OF STUDY Ligusticum wallichi Franchat (chuanxiong) is a very common traditional Chinese herbal medicine in China. Tetramethylpyrazine (TMP) is a major active ingredient extracted from Ligusticum wallichi Franchat. We investigated the protective effect of TMP on interleukin-1β (IL-1β) induced proteoglycan (PG) degradation and apoptosis in rabbit articular cartilage and chondrocytes. MATERIALS AND METHODS Rabbit articular cartilage explants and chondrocytes were cultured with 10 ng/ml IL-1β for 72 h in the absence or presence of various concentrations of TMP (50, 100 or 200 μM). Cartilage and chondroprotective effects of TMP were determined by evaluating (1) the degree of PG degradation by measuring the amount of glycosaminoglycan (GAG) released into the culture media with 1,9-dimethylmethylene blue (DMMB) assay in cartilage explants; (2) gene expression of MMP-3 and TIMP-1 by real-time quantitative reverse transcription-polymerase chain reaction analysis in cartilage explants; (3) chondrocytes viability with MTT assay; (4) the production of intracellular reactive oxygen species (ROS) with laser scanning confocal microscopy (LSCM). Anti-apoptotic effects of TMP were determined by measuring (1) apoptosis with flow cytometric analysis; (2) mitochondrial membrane potential assay with LSCM; (3) caspase-3 activity with special assay kit. RESULTS IL-1β treatment increased the level of GAG released into the culture media, and induced the gene expression of MMP-3 and inhibited the gene expression of TIMP-1 in cartilage explants. Moreover, IL-1β treatment decreased the cell viability and mitochondrial membrane potential, and enhanced the level of intracellular ROS, apoptosis rate, and caspase-3 activity in chondrocytes. However, simultaneous treatment with TMP attenuated the IL-1β-induced cartilage and chondrocyte destruction in a dose-dependent manner. TMP showed the decrease of GAG degradation and MMP-3 mRNA production, and the enhancement of TIMP-1 mRNA production in cartilage explants. TMP also increased the cell viability in chondrocytes. Furthermore, TMP inhibited the chondrocytes apoptosis through suppression of ROS production, maintaining of mitochondrial membrane potential and downregulation of caspase-3 activity. CONCLUSION These results demonstrate that TMP has the cartilage and chondroprotective effect, which suggest that TMP could act as an agent for pharmacological intervention in the progress of OA.

Effect of repeated freezing–thawing on the Achilles tendon of rabbits

The increased use of allograft tissue in the reconstruction of anterior cruciate ligament has brought more focus to the effect of storage and treatment on allograft. The purpose of this study was to observe the effect of histology and biomechanics on Achilles tendon in rabbits through repeated freezing–thawing before allograft tendon transplantation. Rabbit Achilles tendons were harvested and processed according to the manufacture’s protocol of tissue bank, and freezing–thawing was repeated three times (group 1) and ten times (group 2). Those received only one cycle were used as controls. Then, tendons in each group were selected randomly to make for histological observations and biomechanics test. Histological observation showed that the following changes happened as the number of freezing–thawing increased: the arrangement of tendon bundles and collagen fibrils became disordered until ruptured, cells disrupted and apparent gaps appeared between tendon bundle because the formation of ice crystals. There were significant differences between the experimental and control groups in the values of maximum load, energy of maximum load and maximum stress, whereas no significant differences existed in other values such as stiffness, maximum strain, elastic modulus, and energy density. Therefore, repeated freezing–thawing had histological and biomechanical effect on Achilles tendon in rabbits before allograft tendon transplantation. This indicates that cautions should be taken in the repeated freezing–thawing preparation of allograft tendons in clinical application.