The incidence of infection remains 1–2% after primary total joint arthroplasty and even higher after revision procedures in spite of advances in prophylactic antibiotics and clean air operating theatre environment. Detection of low-grade infection in a prosthetic joint can often be very difficult. None of the investigations available so far have 100% sensitivity and specificity. This has huge implications on the subsequent treatment, cost and patient morbidity. Revision of an unrecognized infected arthroplasty may lead to less satisfactory results in a high proportion of cases. We utilized Polymerase Chain Reaction, a molecular biology technique to detect bacterial DNA from the synovial fluid of patients undergoing revision surgery. We prospectively assessed 70 patients undergoing revision arthroplasty (57 hips and 13 knees). Each patient was pre operatively assessed clinically and radiologically. ESR and CRP results were noted. During revision, synovial fluid and tissue cultures from capsule, bone and bone-cement interface were obtained. None of the patients received pre or intra operative antibiotics till the specimens were taken. Standard microbiology and histology study were done on tissue samples. In addition Polymerase Chain Reaction study was done on the synovial fluid. In this method, DNA is extracted from the bacterial cell, it is polymerized and finally visualized by gel electrophoresis. Post operatively patients were followed up at regular intervals. Diagnosis of infection included correlation between clinical, radiological and laboratory investigations along with intraoperative findings, tissue culture and histology results and a period of post operative follow up (12 months to 36 months). Six (8%) of the 70 cases that had revision arthroplasty were clinically infected. Polymerase chain reaction was positive in 25 cases, tissue cultures were positive in 5 cases and histology was positive in 5 cases for infection. PCR showed sensitivity and specificity of 83% and 69% respectively. Tissue culture showed sensitivity and specificity of 83% and 100% respectively. Histology showed sensitivity and specificity of 83% and 100% respectively. 20 out of 25 PCR positive cases did not show any clinical evidence of infection. It is unclear whether this represents contamination during surgery or in the PCR lab. Alternatively this may represent true positive PCR results in cases with low bacterial count that can be detected by ultrasonication of implant and immunofluorescence methods. PCR is more sensitive in detection of bacterial DNA. However it has low specificity and combination of tissue cultures and histology can still provide a reliable diagnosis of infection.
Frozen shoulder is a chronic fibrosing condition of the capsule of the joint. The predominant cells involved are fibroblasts and myofibroblasts which lay down a dense matrix of type-I and type-III collagen within the capsule. This subsequently contracts leading to the typical features of pain and stiffness. Cytokines and growth factors regulate the growth and function of the fibroblasts of connective tissue and remodelling of the matrix is controlled by the matrix metalloproteinases (MMPs) and their inhibitors. Our aim was to determine whether there was an abnormal expression or secretion of cytokines, growth factors and MMPs in tissue samples from 14 patients with frozen shoulder using the reverse transcription/polymerase chain reaction (RT/PCR) technique and to compare the findings with those in tissue from four normal control shoulders and from five patients with Dupuytren’s contracture. Tissue from frozen shoulders demonstrated the presence of mRNA for a large number of cytokines and growth factors although the frequency was only slightly higher than in the control tissue. The frequency for a positive signal for the proinflammatory cytokines Il-1β and TNF-α and TNF-β, was not as great as in the Dupuytren’s tissue. The presence of mRNA for fibrogenic growth factors was, however, more similar to that obtained in the control and Dupuytren’s tissue. This correlated with the histological findings which in most specimens showed a dense fibrous tissue response with few cells other than mature fibroblasts and with very little evidence of any active inflammatory cell process. Positive expressions of the mRNA for the MMPs were also increased, together with their natural inhibitor TIMP. The notable exception compared with control and Dupuytren’s tissue was the absence of MMP-14, which is known to be a membrane-type MMP required for the activation of MMP-2 (gelatinase A). Understanding the control mechanisms which play a part in the pathogenesis of frozen shoulder may lead to the development of new regimes of treatment for this common, protracted and painful chronic fibrosing condition.
The incidence of horizontal cleavage lesions of the menisci was studied in 100 random necropsy examinations. Sixty per cent of subjects had at least one such tear, the incidence being 29 per cent out of the 400 menisci. Eighty-five per cent of the subjects showed changes of osteoarthritis in the patello-femoral or tibio-femoral joint compartments. The coincidence of horizontal cleavage lesion and osteoarthritis was frequent. Horizontal cleavage lesions were commoner in medial or larger menisci and in males. Eighteen per cent of the menisci were calcified and this was twice as common in those menisci with a degenerate tear. Because the horizontal cleavage lesion was so common in the older knee, it must usually remain unrecognised clinically with other factors causing symptoms of night pain and tenderness.
1. Thirteen cases of occipito-cervical fusion performed in the past fifteen years at the London Hospital are described. 2. Seven of the patients had congenital anomalies in the region of the foramen magnum, six had spontaneous atlanto-axial dislocations, and in one case the operation was performed prophylactically to stabilise a severely disorganised cervical spine. 3. Nine of the patients had evidence of neurological involvement before operation due to pressure on the spinal cord or nerve roots. 4. Operative fusion was successful in all cases and there was no operative mortality. 5. The clinical results were good in eight cases and four patients were improved. The condition of one patient, in whom progressive disseminated sclerosis was also present, deteriorated. 6. The technique of operation is described, and it is recommended that it should always be performed as a combined orthopaedic and neurosurgical procedure.
1. Two cases of pseudogout are described with an onset acute enough to be mistaken for septic arthritis. 2. The radiological and laboratory investigations for diagnosis are described.
