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The lubrication mechanism of natural and artificial human joints was discussed in this paper. The history of joint lubrication research was reviewed briefly. Some key problems in joint lubrication were addressed. The clinical use of results obtained in studies of joint lubrication mechanism was also discussed in the paper.
Of 162 metacarpophalangeal silicone prostheses inserted from 1967 to 1973, fifteen fractured, two were associated with an infection, and there was one case of skin necrosis. A recurrence of ulnar drift occurred in four hands. Three prostheses had to be removed and in one such case additional significant foreign-body reaction was evident. Although the complication rate was over 10 per cent, the failure rate was fairly low.
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To understand the effects of load-bearing on cementless fixation of porous coated implant, we inserted Co-Cr-Mo alloy implants into the distal femur of rabbits. Specimens were studied by means of histology, anti-collagen type I and III immunohistochemical staining, colloidal gold labeled immunoelectron microscopy, and computerized graphic analysis. The results revealed that stimulations of load-bearing benefited bone ingrowth, but the newly formed bone in the pores was absorbed and replaced by fibrous tissues after 12 weeks without stimulations of load-bearing. The fibrous tissues in the pores of the implant were primarily type III collagen after one week and type I collagen after two weeks. After 6 weeks, the residual tissue between ingrowth bone and metal bound antibodies was type I collagen. Fibroblasts participated in and possessed the action of osteogenesis.
Experience in endoprosthesis of great joints in 408 patients in difficult clinical cases associated with defects and deformations of bones of posttraumatic, oncological, dysplastic and systemic character, and also in the cases of complications after primary endoprosthesis is analyzed. Special constructions of implants, instruments, surgical technique were used depending on anatomic and functional changes. Results of endoprosthesis of great joints were accessed as successful in 95% patients in maximal period of follow-up during 13 years.
The properties of the synovial fluid and the results of the electrophysical studies of the fluid by the thermoelectret method are briefly described. The interrelation between current peaks on the thermostimulated current spectra of thermostimulated currents of the synovial fluid and the liguid-crystalline state of its components was established. The results can be used for developing the methods of diagnostics of synovial joint diseases and design of artificial joints.
OBJECTIVE: To assess factors associated with permanent work disability (PWD) in Mexican subjects with rheumatoid arthritis (RA). METHODS: From a database of 300 salaried workers with RA, we evaluated 35 cases that developed PWD. These cases were compared with 70 controls randomly selected from the same database who were active workers. The assessment included the following variables: sociodemographic, education, employment, and clinical characteristics of the disease. Logistic regression analysis was performed to adjust variables associated with PWD. Odds ratios and their 95% confidence intervals (95% CI) were computed. RESULTS: Factors associated with PWD in the unadjusted analysis were: lower education level (OR 3.27, 95% CI 1.28-8.49, p = 0.006), >or= 2 year delay in prescription of a disease modifying antirheumatic drug (DMARD) (OR 4.29, 95% CI 1.49-12.73, p = 0.02), joint prosthesis (OR 8.93, 95% CI 2.02-45.04, p < 0.001), severe radiographic damage (OR 3.33, 95% CI 1.20-9.46, p = 0.01), comorbidity (OR 7.54, 95% CI 1.94-34.25, p < 0.001), and positive rheumatoid factor (RF) (OR 3.53, 95% CI 0.98-13.76, p = 0.03). In the multivariate model PWD was predicted by lower education (OR 3.3, 95% CI 1.1-9.7, p = 0.03), positive RF (OR 4.9, 95% CI 1.2-19.7, p = 0.03), and delay in the prescription of a DMARD (OR 3.3, 95% CI 1.1-10.1, p = 0.04). CONCLUSION: A low education level, positive RF, and delay in the use of DMARD are risk factors for PWD. Strategies to decrease rates of PWD should include an earlier treatment with DMARD.
Detection of focal infections aims at the identification and subsequent treatment of sources of odontogenic inflammation in order to prevent health threats in patients who are often medically compromised. Examination for dental foci often precedes medical treatment of patients with increased risks of endocarditis, patients with a joint prosthesis, patients scheduled for chemotherapy or head and neck radiotherapy or candidates for organ transplantations. Although examination for possible sources of dental inflammation is performed on a routine basis in many hospitals, the scientific basis for this policy apparently is very limited, and there is an evident need for well-designed randomized clinical trials in this field.
The concentration of 99mTc-pyrophosphate was determined in the lower extremities of rabbits (normal, abacterial and bacterial affected soft tissues), in osteoarthritis of the hip joint (capsule and muscle) as well as in knee joint effusions. Compared with the 85Sr-concentration, reflecting the calcification capacity, concentrations of 99mTc-pyrophosphate in soft tissues were found to be lower 2 hours p.i., but were up to elevenfold higher 24 hours p.i. These findings should be due to a fixation of 99mTc-pyrophosphate in collagen containing tissues as in the soft tissue tumors (myosarcoma, synvialioma, breast cancer) presented. A mechanism of delayed equilibration could explain augmented uptake in lymph-edema, ascites and effusions in florid osteoarthritis of the knee joint. The possible dependence of 99mTc-pyrophosphate concentration in bone and soft tissue on collagenous contents is discussed.
Between 1983 and 1988 revision arthroplasty was performed in 45 patients with broken femoral stems, an average of 11 years after primary total hip replacement. There were 25 men and 20 women, with an average age of 70 years at revision. The primary endoprostheses were all cemented and of the following types: Buchholz A1 (41) Charnley-Müller (2), Weber-Huggler (1), Charnley (1). In 8 cases the femoral stem only was changed, while in 37 both components had to be replaced. The posterior approach with the patient in the lateral position gave excellent exposure of both the acetabulum and the femur. This approach gave ready access to a dorsal window, through which the broken femoral stem could be removed with a punch. To achieve stability of the femur permitting immediate full weight-bearing, the femoral defect was always made good by a revision stem with at least twice the femoral diameter. In order to stabilize large acetabular defects a combination of homologous bone graft and an acetabular support ring was used. The implanted prostheses were of the revision type, cemented and individually selected in each case. It was possible to implant an adequate revision prosthesis in all cases. The following complications were noted during surgery: fracture of the femur (1) defects of the femur (5), and haemorrhages that were difficult to manage (2). It was necessary to reoperate in 2 patients, in 1 because of a stitched-up drain and in 1 because of postoperative haematoma. Postoperatively, 21 patients had cardiopulmonary complications, which were successfully treated in the intensive care unit in all cases but 1.(ABSTRACT TRUNCATED AT 250 WORDS)
In addition to hemodilution and preoperative blood donations, mechanical intraoperative autotransfusion (MAT) is an important method of preventing or minimizing the transfusion of homologous blood in operations with major blood loss. Using cell separators allows most of the problems of MAT to be solved, but the processed red cell concentrates of patients having hip joint replacement contain fat. Due to the high risk of fat embolism during bone surgery, as well as other circulatory problems, it is of interest whether the infusion of up to 15 ml of fat does not expose patients to an even higher risk. This study aimed to research the pathogenesis of fat embolism and possibly support one of the existing theories. METHODS. Semiquantitative oil measurement: in 45 cases with first insertion of hip joint prosthesis and 16 cases with change of prosthesis MAT was used intra- and postoperatively. For comparison, 10 patients with aortic aneurysm repair were checked for fat as well. In these cases MAT was only used intraoperatively. After the red cell concentrate was processed there was a time lag of 10 min to allow better sedimentation of fat. At the end of retransfusion 50 ml of blood were saved. They were then separated into 10-ml plastic tubes, centrifuged, and fat content was measured using a mm-scale. The results were transformed to ml by means of a previously determined calibration. Analogous to hematocrit values, it was thus possible to establish a lipocrit for these patients. In another 16 cases of hip surgery we carried out cholesterol/triglyceride investigations in red cell concentrates, and in 5 cases analysis of the fatty acids by gas chromatography was performed. RESULTS. The lack of an emulsifier causes biochemical analysis of cholesterol-triglyceride levels to be impossible. Therefore, triglycerides and cholesterol in MAT blood were below normal levels although a high quantity of fat could be seen in the blood. No oil was found in any of the patients in the vascular surgical group. There were 61 patients in the orthopedic group; no oil was found in 34.4%, we found 1-2 ml in 16.4%, and in 49.2% there was more than 2 ml of oil. With regard to age, sex, weight, height, and deviation from Broca index no significant difference in lipocrit could be seen. Differences in lipocrit were observed depending on the type of operation (i.e. new insertion/change of hip prosthesis), these were not significant possibly due to the small number of patients undergoing a change of prosthesis. The more MAT blood was transfused, the more significant were the rises in lipocrit level. The rinsing solution itself (1000 ml NaCl 0.9% with heparin 30,000 IU) does not influence the oil concentrations. Gas chromatography revealed that there was more than 40% oleic acid and 20% palmitic acid. Combined with linoleic acid, this comprised 4/5 of the total amount of oil (Table 3)...
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The utilization and effectiveness of a pre-operative autologous blood donation programme were analyzed at a small, 40-bed, general hospital with subspecialization in orthopaedic surgery. Over a period of 8 months, 13 patients who were all to undergo total knee or hip replacement were evaluated. Twelve patients were found suitable and they donated in mean 1.9 units of blood. At discharge the patients who had donated blood pre-operatively had the same mean hemoglobin value as a comparable group of patients who only received blood from the ordinary blood bank service in spite of the total transfusion demand being the same in the two groups. The pre-donated blood covered 54% of the total demand of the group evaluated. The method is found especially applicable at small hospitals, where the administrative problems concerned with the method are easy to manage.
Scintigraphy with indium-labeled white blood cells has been reported to be sensitive and specific in the diagnosis of low-grade sepsis of the musculoskeletal system. We reviewed the records of fifty patients who had suspected osteomyelitis or suspected infection about a total joint prosthesis and who underwent scintigraphy with technetium-99m methylene diphosphonate and scintigraphy with indium-111 oxine-labeled white blood cells before an open surgical procedure. Any patient who received preoperative antibiotics was not included in the study. For all of the patients, gram-stain examination of smears, evaluation of a culture of material from the operative site, and histological examination were done. The patients were divided into two groups. Group I was composed of twenty-four patients, each of whom had a prosthesis in place and complained of pain. Group II was composed of twenty-six patients for whom a diagnosis of chronic osteomyelitis had to be considered. With the indium scans alone, there was only one false-negative result (in Group II), but there were eighteen false-positive results (eight patients in Group II and ten patients in Group I). Although scintigraphy with indium-labeled white blood cells is quite sensitive, it is not specific in detecting chronic osteomyelitis; a negative scan should be considered highly suggestive that osteomyelitis is not present. Specificity can be increased by interpreting the indium scan in conjunction with the technetium scan.
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Looking ahead, one envisions an era of remarkable progress in the study of the healing of bone and cartilage. The physical, biochemical, and biomechanical factors governing bone and cartilage healing will be defined and manipulated to accelerate the healing process. Joint stiffness, the undesirable sequela of many simple fractures of the hand as a result of prolonged immobilization, will be obviated. For cases of limited joint damage, techniques for joint reconstruction will be refined. For non-salvageable bone and joint destruction, microvascular allogenic transplantation of skeletal units will become a reality. Silastic implants in the wrist will become historical oddities.
The following should be regarded as prerequisites for successful surgical treatment: careful assessment of the local problem and of the patient as a complete individual; a thorough understanding of the biomechanical implications of the disease and of the operations used in its management; a clear definition of the goals of surgery in both the patient's and the surgeon's minds; and very careful planning with regard to the timing and sequence of operations. Other factors of major importance, especially in multijoint reconstructive programmes, are careful patient selection, the early establishment of good doctor/patient rapport, the support of a highly skilled multidisciplinary team of health professionals, and impeccable supervision of the convalescence, especially at the particularly difficult period for the patient following discharge from hospital. Finally, the hospital team must be prepared to offer a permanent service as a readily available advice bureau for family doctors, patients, and their relatives.