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.     

Pathologic supracondylar fracture due to osteolytic pseudotumor of knee following cementless total knee replacement

Kimura's Disease, a rare chronic inflammatory disorder with a benign course affecting the lymphoid tissue is reported hare in an 18 year old South Indian male who presented with bilateral solitary swelling over the mastoid region. Its fine needle aspiration cytology characterised by the Warthin-Finkeldey type giant cells against a background of a bimodal population of lymphocytes and eosinophils prompted the diagnosis of Kimura's disease at cytology itself. This was confirmed at histology. This is the third cytological report of its kind being reported in English literature. Literature with regard to the cytological appearances of Kimura's disease has been reviewed and the various differential diagnoses discussed.     

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.     

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.     

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).     

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.     

Dislocation following primary posterior-stabilized total knee arthroplasty

From 1981 through 1991, 3,032 primary total knee arthroplasties were performed using the Insall-Burstein Posterior Stabilized Condylar Prosthesis (IB-I, IB-II, and IB-II modified) (Zimmer, Warsaw, IN). Fifteen posterior dislocations occurred: 4 with the IB-I system occurring 2 or more years after surgery, 10 with the IB-II system (8 occurring 6 months after surgery and 2 occurring 2-3 years after surgery), and 1 with the IB-II modified system occurring 9 months after surgery. Statistically significant differences for the rate of dislocation between both the IB-I and IB-II modified arthroplasties versus the IB-II arthroplasties were found (P < .001). In an attempt to identify a cause for these dislocations, the authors retrospectively assessed the 15 dislocated cases with respect to sex, age, weight, height, preoperative and postoperative Hospital for Special Surgery scores, preoperative and postoperative alignment, preoperative versus postoperative reconstruction dimensions, patellar thickness and height, and postoperative flexion and compared the results with those patients who did not experience dislocation. Possible etiologies and mechanisms of dislocation were sought. There were no significant differences between the control and study groups for any variable assessed, with the exception of postoperative flexion, which averaged 118 degrees for the study group and 105 degrees for the control group (P < .001). Conservative management was successful in 11 cases. In September 1988 the IB-II system was introduced; modification of the tibial insert was made in January 1990.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

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.     

Statistics of total knee replacement: partial and total knee replacement, design St. Georg: a review of a 4-year observation

Since 1969, we have used 2 different types of knee prostheses to reconstruct arthritic knees. The surface replacement prosthesis (sledge) is indicated where ligamentous stability is present and angular deformity is not severe. In addition, the sledge prosthesis may be implanted with good results in selected acute comminuted tibial plateau fractures. The total hinged prosthesis of metal design is recommended in knees which are severely deformed, and unstable, and therefore not suitable for the sledge prosthesis. Marked relief of pain was the most significant result in our patients. Residual knee pain was most frequently due to patello-femoral pain and, when severe, this was satisfactorily controlled by performing a patellectomy. Motion was usually maintained at the preoperative range or improved, mainly by reducing or eliminating the knee flexion contracture. In a high percentage, the unicompartmental sledge prosthesis has given excellent results. However, we tend to insert a bi-compartmental sledge prosthesis because experience has shown that even slight damage of the articular surfaces of the opposite side is likely to further deteriorate rapidly. Although a significant number of complications occurred, these have been minimized by further conservative and operative treatment. We anticipate a further reduction in complications based on our initial experience, and prosthetic revisions.     

Peripheral nerve blocks improve analgesia after total knee replacement surgery

Using an in vitro cell system and Cs+ NMR techniques we were able to show that porcine aortic endothelial cells (PAEC) reduce their Na(+)-K(+)-ATPase activity upon an increase in intracellular cAMP. Reduction in the pump rate was due to phosphorylation of the alpha-subunit of the ATPase as shown by immunoprecipitation. Apart from a pump inhibiton using 8-Br-cAMP and IBMX, we were also able to show that changes in the Na(+)-K(+)-ATPase activity could be mediated by the adenosine-A2 and prostaglandin receptor agonists 5'-N-Ethylcarboxamidoadenosine and Iloprost, respectively. Parallel to a decrease in pump activity we also observed a decrease in intracellular Cs+, indicating opening of K+ channels.     

Heterotopic ossification following total knee arthroplasty requiring surgical excision

We present a case of progressive heterotopic ossification (HO) after cementless total knee arthroplasty causing painful stiffness that was treated with surgical excision. The patient had few risk factors associated with HO, including minimal anterior notching and dissection of the distal femoral cortex. The patient did undergo manipulation; however, this occurred after the diagnosis of HO was made. This report documents a rare case of HO following total knee arthroplasty that required surgical excision.     

Shift and tilt of the bony patella in total knee replacement

Resurfacing the patella or not in total knee arthroplasty is generally still a quite controversial topic. In that context we felt a necessity to get more informations about the natural history of a non resurfaced patella in the prosthetic surrounding than only in comparison with a replaced patella. By the fact that we haven't been replacing patellae apart from special cases since up to five years, we have available a patient selection on which this question can be studied. Thirty primary total knee replacements with documented 2 year's follow up have been investigated by calculation of the radiological patellar shift and tilt relative to the natural groove on preoperative X-rays and to the prosthetic groove in the postoperative evolution. These results were matched with the range of motion obtained after two years and with persisting pain. Only mobile polyethylene inlays had been used. With regard to the patella no difference was found for one single complete tibial tray or two separately implanted unicompartimental tibial trays. As a rule an adaptation of the bony patellar contour to the prosthetic groove was observed with an increased density of the bony contact area with or without a fibrous interstitial layer. Based on their clinical follow up examination seven patients had to be adjointed to a "residual problem group", as they presented persisting pain (3) or a poor range of motion of 90/0/0 degree of flexion/extension or less. Only in this group we found cases with a postoperative shift over 5 mm (2) and a postoperative tilt over 15 degrees (3). Inside this group, also with a significant difference from the group without residual problems, there was furthermore a correlation between persisting pain and an important preoperative tilt and between a diminished range of motion and a considerable preoperative shift. It has to be pointed out that even the cases without long severe malposition before the arthroplasty but with unsatisfactory realignement referring to the patellar tilt (7 degrees-15 degrees) have been found pain free at the last follow up. One patient with a severe secondary increase of disalignment (16 mm/139 degrees) due to an aseptic tibial loosening represents a particular case. After corrective revision of the tibial implants this patient also got again a complete pain relief and a good range of motion without any surgical measure to the patella and inspite of an evident residual tilt. Thus we have to conclude that it is justified to take important pains with the realignment to obtain a residual patellar shift of less than 5 mm. Apart from usual operative steps during the implantation to favour a good patellar tracking, e.g. a high quadriceps release or a medially transposed refixation of the detached tibial tubercle can get necessary. On the other hand a residual tilt up to 15 degrees is well tolerated, as the unresurfaced patella presents an astonishing ability of adaptation to the prosthetic groove by remodelling of the bony contour and structure. Nevertheless in the included cases of severe preoperative malposition, in which we didn't replace the patella because of a good intraoperative bone quality, we had to put up with an increased incidence of late problems even with normalized patellar tracking. In such cases an extended indication to a patellar resurfacing may be considered.     

Effect of component positioning on patellar problems in total knee replacement

The alignment and size of the components of a knee-prosthesis is most important for a successful and durable total knee arthroplasty. The effect of positioning the components on the patellafemoral joint is described in detail.     

Radiographic pseudochondrocalcinosis in early failure of a cemented total knee replacement

We observed a case of early-onset osteolysis in a cemented total knee arthroplasty. Preoperative radiographs suggested numerous radiopaque particles covering the polyethylene insert. Findings at the time of revision confirmed the presence of small radiopaque polymethylmethacrylate particles on the bearing surface of the tibial insert, presumably leading to early failure of the knee arthroplasty.