Screw home motion after total knee replacement

The objective of this study was to evaluate the effect of muscle force and the posterior cruciate ligament on screw home motion in patients with total knee replacement in a posterior cruciate ligament retaining prosthesis (10 knees) and a posterior cruciate ligament substituting prosthesis (10 knees). Screw home motion was examined with only active extension and with two types of externally loaded active extension (2 kg and body weight). Screw home motion was measured with a 6 degrees of freedom electrogoniometer (instrumented spatial linkage). Retaining the posterior cruciate ligament maintained screw home motion, with and without external load to muscles, whereas substituting the posterior cruciate ligament maintained screw home motion only under the full external load of body weight. This was not seen with a 2-kg external load. As for the normal knee, it appears that screw home motion of a prosthetic knee is influenced, not only by the presence of ligamentous structures, but also by the activity of the muscles. The activity of the muscles may have a much greater effect on screw home motion with currently used prosthetic designs than does the presence of ligamentous structures.     

Cell salvage auto transfusion in total knee replacement surgery

We present the case of a 51 year-old-white male with a giant right renal arteriovenous fistula secondary to a carcinoma. Neither the aorta nor the kidneys were visualized after the injection of 60 mL of contrast media into the abdominal aorta. Moreover, the right kidney could not be visualized after 30 mL of contrast media were injected selectively into the right renal artery. This was due to a great arteriovenous shunt through the right kidney. The right renal angiogram was obtained through digital imaging, after injecting contrast media into the right renal artery, previously occluded by a balloon-catheter. The image of an hypervascularized nephroma was obtained, depicting an important arteriovenous shunt of the contrast material toward the inferior vena cava from a fistula located in the right inferior renal pole. The occlusion of the right renal artery was partially achieved by injecting 40 mL of boiling contrast media, followed by small fragments of Gelfoam suspended in the contrast substance. The balloon-catheter remained inflated in the right renal artery until a nephrectomy was performed. As far as we know, a case in which the aorta and renal circulation are unable to be seen by means of conventional angiography, because of the presence of a renal arteriovenous shunt to the fistula, has not been described.     

Uni-compartment total knee replacement

Twelve patients with uni-compartment total knee replacement were followed for a period of 12 to 30 months with an average follow-up of 19 months. Results in 11 out of 12 patients suggest that this operation is an alternative to high tibial osteotomy or hemiarthroplasty in selected patients. Long term end result studies are necessary to evaluate uni-compartment total knee replacement as a durable procedure for the management of knee arthritis.     

Patient-controlled analgesia versus patient-controlled analgesia plus continuous infusion after hip replacement surgery

OBJECTIVE: To compare the efficacy and adverse effect profile of patient-controlled analgesia (PCA) versus PCA plus continuous infusion (PCACI) after hip replacement surgery. DESIGN: Prospective, randomized, open pilot study. SETTING: Large teaching institution. PARTICIPANTS: Thirty-four patients undergoing hip replacement or revision of hip replacement surgery. INTERVENTIONS: Patients were randomized to receive PCA morphine: 1 mg with 6-minute lockout, or PCACI, using the same dose, with a 0.5-1 mg/h continuous infusion. Pain intensity, sedation, narcotic use, injection/attempt ratio (I/A), and adverse effects were assessed. RESULTS: No significant differences in pain intensity were identified. Morphine use was not different between groups: PCA 61.8 +/- 35.0 and PCACI 74.2 +/- 54.9 mg (p =0.394). A trend toward an increased 12-hour I/A ratio was evident in the PCACI group: PCA 0.73 +/- 0.18 and PCACI 0.86 +/- 0.17 (p =0.073). Patient-reported adverse effects, sedation, and inability to sleep secondary to pain occurred similarly. Eight of 18 PCACI patients required discontinuation of either the continuous infusion mode or of PCA therapy entirely secondary to adverse effects. CONCLUSIONS: When compared with PCA therapy, PCACI was not associated with improved pain control and more patients receiving PCACI required discontinuation of therapy secondary to adverse effects.     

Venous haemodynamics in both legs after total knee replacement

We studied the effect of total knee replacement on venous flow in 110 patients. Resting venous blood flow was measured using strain-gauge plethysmography before operation, after surgery and after discharge from hospital. There was a significant reduction in mean venous capacitance (p < 0.001) and mean venous outflow (p < 0.004) affecting only the operated leg. Both improved significantly after mobilisation in the early postoperative period, returning to preoperative levels by six days after surgery and before discharge from hospital. Our findings showed that venous stasis may contribute to deep-vein thrombosis only in the first few days after total knee replacement. This would be the most important period for the use of flow-enhancing prophylactic devices. Comparison with changes in blood flow after total hip replacement identified different patterns of altered haemodynamics suggesting that there are different mechanisms of venous stasis and thrombogenesis in hip and knee arthritis and during surgery for these conditions.     

Complications following total knee replacement

Forty-two months follow-up examinations on 30 total knee arthroplasties revealed the following significant complications: phlebothrombosis, 13 knees (46%); pulmonary embolism 3 patients (11%); asymptomatic loosening, 8 knees (11.4%); symptomatic loosening, 3 knees (4.8%); superficial infections, 4 knees (5.4%); deep infections, 4 knees (5.4%); peroneal palsy, 3 patients (4.3%). Early detection of thrombophlebitis by 125I fibrinogen scan and possible aspirin prophylaxis were evaluated. In view of the limited number of encouraging results, e.g. excellent 58.6 per cent; good 28.5 per cent; fair 5.4 per cent and poor 7.1 per cent, caution is advocated until extensive time elapses for more clinical experience with total knee arthroplasty.     

Renal dysfunction after total knee replacement is not aggravated by bone cement

BACKGROUND: Total knee replacement (TKR) has been associated with postoperative renal dysfunction. The use of monomeric methylmethacrylate (MMA) bone cement causes hypotension by several mechanisms. METHODS: In 30 patients undergoing TKR with (n = 16), or without (n = 14) bone cement, serum levels of creatinine, cystatin C and creatine kinase (CK) and urinary levels of creatinine and markers for glomerular (albumin, IgG) and tubular (protein HC) function were recorded preoperatively and on days 1, 2, 4 and 8 postoperatively. RESULTS: There were no changes in serum creatinine. Both groups had a transient, 5-fold rise in CK and a continuous increase in cystatin C. The urinary concentration of proteins increased postoperatively with a peak in the glomerular markers on day 1 and in the tubular marker on day 2. There were no significant differences in proteinuria between the groups. The 95% CIs for the difference in the means of the AUCs of the logarithmically transformed values for the proteins were never more than 19%. On day 8 all proteins had returned to their preoperative levels. CONCLUSION: Postoperatively, there was a transient increased leakage of proteins, indicating glomerular and tubular dysfunction. This was not influenced by the use of MMA bone cement.     

Joint load considerations in total knee replacement

We have characterized the mutations in 1050 carriers of the beta-thalassemia gene and analyzed their regional distribution in India. The majority of beta-thalassemia carriers were migrants from Pakistan and their pattern of mutations differed from the rest. The frequency of the 619-bp deletion was 33.3% among the migrants from Pakistan, 8-17% in the northern states, and less than 5% in the other states. Among non-migrant subjects, the predominant mutation was IVS-I-5 (G-->C), varying from 85% in the southern states and 66-70% in the eastern states to 47-60% in the northern states. The mutation IVS-I-1 (G-->T) was observed at high frequency among the migrants from Pakistan (26.2%), but with very low/zero frequency in the other states. Mutations at codons 8/9 (+G) and codons 41/42 (-CTTT) were distributed in all regions of India with a frequency varying from 3% to 15%. Only eight of 12 published rare mutations were observed in subjects from different parts of India. Mutations of codon 5 (-CT) and codons 47/48 (+ATCT) were found exclusively in migrants from Pakistan, and mutation -88 (C-->T) was detected only in subjects from Punjab, Haryana, and Uttar Pradesh. Using the amplification refractory mutation system technique, mutations were successfully identified in 98.2% of subjects. Overall, 91.8% of the subjects had one of the five commonest mutations [IVS-I-5 (G-->C), 34.1%; 619-bp deletion, 21.0%; IVS-I-1 (G-->T) 15.8%; codons 8/9 (+G), 12.1%, and codons 41/42 (-CTTT), 8.7%], 5.9% of the subjects had a less common mutation, while 1.8% of the carriers remained uncharacterized. The application of this knowledge has helped to successfully establish a program of genetic counselling and prenatal diagnosis of beta-thalassemia in order to reduce the burden of this disease in India.     

Regional nerve block for total knee arthroplasty

Femoral and sciatic nerve blocks have been used occasionally for unilateral total knee arthroplasty (TKA). In order to evaluate the effectiveness of this technique, combined femoral 3-in-1 and sciatic nerve blocks were performed in 20 cases of TKA, by the same surgeon. This surgeon also performed unilateral TKA under spinal anesthesia in another 20 cases. The anesthetic effectiveness of the two types of anesthesia was compared in terms of the time needed to complete the surgery, amount of intraoperative blood loss, and time interval until the first dose of analgesic. The results showed that the two types of anesthesia had comparable anesthetic effects. Ten of the 20 patients who had spinal anesthesia complained of postoperative urinary retention, while none of those who had nerve block had this complaint. Neither group experienced postpunctural headache, neurovascular damage, or drug-over-dose toxicity. We conclude that combined femoral 3-in-1 and sciatic nerve block is an effective anesthetic alternative for unilateral TKA.     

2-stage reimplantation for infected total knee replacement

Between 1977 and 1983, 64 infected total knee replacements in 60 patients were treated with a 2-stage protocol for reimplantation. The clinical results and survivorship were determined at an average followup of 7.5 years (range, 2-17 years). Surgical protocol included removal of the prosthesis and all cement with thorough debridement of bone and soft tissues. This was followed by 6 weeks of parenteral antibiotics and then reimplantation of a new prosthesis. At followup, 6 knees (9%) had become reinfected, but only 2 with the same organism. Four knees had been revised: 3 for aseptic loosening and 1 for a periprosthetic femur fracture. Two other knees were impending failures due to aseptic loosening. The average Hospital for Special Surgery knee score was 78 points with 18 excellent, 28 good, 13 fair, and 5 poor results. Seventy-eight percent of patients were satisfied with the overall result of their reimplanted prosthesis and 95% think that they made the right decision in undergoing total knee arthroplasty. The 10-year predicted survivorship of 2-stage reimplantation is 77.4%. Two-stage reimplantation with a 6-week course of parenteral antibiotics is an effective means to eradicate deep infection and to provide a functional knee. The long term functional results and overall survivorship are comparable with the results of revision of aseptic failed total knee arthroplasty.     

Thromboembolic disease in patients undergoing total knee replacement

In a prospective study fo the incidence of deep-vein thrombosis in thirty patients undergoing total knee replacement, all patients had clinical examinations and 125I fibrinogen scanning, while those suspected of having deep venous thrombosis also had confirmatory venography. Sixteen (53 per cent) of the thirty patients had thromboembolic disease; nine had thrombi only in the limb operated on; four had bilateral deep venous thrombi; and three had pulmonary embolism. In nine patients who took aspirin regularly the incidence of thromboembolism was 11 per cent, while in the eight who did not take aspirin or any other antiplatelet drug the incidence was 88 per cent, a difference which was highly significant (p = 0.003).     

Minimise outcome measures after knee replacement

In a previous study the "performance variability" of 15 different assessment systems after knee replacement was analysed. The notion that different knee evaluation systems measure different underlying factors was suggested. Three systems that seemed to have different underlying factors were selected, and a factor analysis was carried out to reduce the number of items in each group. The number of items could be reduced by 70%-82% with a minor loss of discriminating capacity. All instruments could be separated into items of pain, strength, mobility or stability. Pain measured on a visual analogue scale and self-selected walking speed were recommended for longitudinal monitoring of the treatment effect after knee replacement.     

Randomised, prospective study comparing cemented and cementless total knee replacement: results of press-fit condylar total knee replacement at five years

OBJECTIVE: The objective of this study was to examine the effect of family and neighborhood income on health care use of young children born prematurely and of low birth weight (N = 619). DESIGN: A birth cohort was enrolled in a clinical randomized trial of early childhood educational and family services. SETTINGS/PARTICIPANTS: Infant Health and Development Program provided a sample of low birth weight premature infants stratified by clinical site, birth weight, and treatment group. Maternal reports of health care use, family income, and heath insurance were obtained at 12, 24, and 36 months of corrected age. Neighborhood income was based on census tract residence at birth. MAIN OUTCOME MEASURES: Maternal reports of hospitalizations, doctor visits, and emergency department visits were used; data were averaged over the child's first 3 years of life. RESULTS: Children from poorer families were more likely to be hospitalized and to have more emergency department visits than were children from more affluent families. Residence in poor and middle-income neighborhoods was associated with more emergency department visits than residence in affluent neighborhoods. Families in middle-income neighborhoods reported more doctor visits than families in poor or affluent neighborhoods. CONCLUSION: Neighborhood residence influences health care use by poor and nonpoor families and by insured and uninsured families. The use of the emergency department for low birth weight premature children in middle-income and poor neighborhoods is discussed.     

人工膝关节置换术后护理研究进展

综述了人工膝关节置换术后护理,包括术后进行正确的护理,严密观察病情,积极预防并发症,制订整体的康复计划、促进患者早期功能锻炼,同时加强心理护理等.认为完善的术后护理可以减轻患者痛苦、防止并发症的发生、促进膝关节功能的恢复,减少住院时间和经济费用,提高患者生活质量.     

Hope, self-efficacy, and functional recovery after knee and hip replacement surgery.

Objective: To test hypothesized relations between hope and self-efficacy for rehabilitation to depression and functional ability reported by individuals receiving joint replacement surgery. Study Design: Community-dwelling older adults (N = 100) from an orthopaedic clinic were administered measures of hope, self-efficacy for rehabilitation, pain, depression, body mass index (BDI), and mental status 1 month prior to their joint replacement surgery. These measures were completed by 62 participants 6 weeks after surgery. Demographic, health information, and functional outcome measures were obtained by medical personnel pre- and postsurgery. Main Outcome Measures: Functional outcome measures (Harris Hip and Knee Society Scores) and depressive symptomatology. Results: Hope was significantly predictive of presurgery depression, but it was not predictive of depression or functional ability after surgery. Higher levels of self-efficacy were predictive of lower postsurgery depression scores. Conclusions: Results imply that social-cognitive constructs may have utility in the prediction of emotional adjustment before and after joint surgery, but they may have limited value in anticipating functional abilities following these surgeries. Theoretical and clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)