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An experimental study of a sensor-controlled external knee locking system.
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Hazards of acrylic bone cement. A report of two cases.
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Stromelysin, gelatinase A and TIMP-1 in prosthetic interface tissue: a role for macrophages in tissue remodelling.
Aseptic loosening of prosthetic components is the most important long-term complication of total joint replacement. To investigate the underlying destructive mechanisms, periprosthetic tissues from both well-fixed and loosened sites from six patients, undergoing surgery for aseptic loosening of knee or hip prostheses, were analysed in detail by immunohistochemical methods for the presence of matrix metalloproteinases and tissue inhibitor of metalloproteinases-1 (TIMP-1). The tissues contained small numbers of cells positive for either collagenase, stromelysin, gelatinase A or TIMP-1; these were randomly distributed, neither specifically next to the bone interface nor to wear particles, and the number of positive cells did not correlate with macroscopic observations at operation. Gelatinase A was co-localized in cells with prolyl-4-hydroxylase, an enzyme involved in collagen synthesis. The predominant cell type in these tissues was shown to be the macrophage by the use of cell marker antibodies. Dual localization was not technically possible but the results strongly suggest that monocyte/macrophages were the primary source of gelatinase A and TIMP-1. Stromelysin was immunolocalized on connective tissue matrix in four patients, and gelatinase A in one patient, and were also observed in tissues in which there was no evidence of cellular synthesis of these enzymes. This suggests that secretion had taken place previously, resulting in enzyme bound to matrix for some time. Taken together, these data indicate that localized focal connective tissue remodelling occurs in periprosthetic tissues from both well fixed and loosened sites.
A scanning electron microscopic study of wear in the plastic components of prosthetic knee and hip joints.
The polyethylene surfaces of four metal on plastic prosthetic knee joints were compared with those of four hip joint replacements, by the use of scanning electron microscopy. The acetabular components of the hip joints showed concentric machining marks, but were generally smooth, and in some areas plastic deformation of the articular surface was evident after 24 months' use. In contrast, the tibial components of knee joints removed after 12 to 22 months showed deep scoring and pitting near the centre of their articular surfaces. This appeared to be due to abrasion by a third material, possibly fragments of cement, which sometimes became embedded in the joint surface. These results indicate that wear in prosthetic knee joints may be much more rapid than in hip joint replacements made from similar materials.
The performance of multiple joint procedures at one operation in a patient with haemophilia.
A haemophiliac patient with crippling degenerative joint disease is described in whom arthrodeses of the left knee and right ankle and total replacement of the left ankle were performed in the course of one operation. The reasons for this and for using a total ankle replacement are discussed.
Surgery in rheumatoid arthritis. A. Synovectomy. B. Joint replacement.
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Symposium on arthritis in older persons. Section IV. Surgery and rehabilitation. Total joint replacement: lower extremities (Summary of presentation).
In experience with total joint replacement in the lower extremity, to date, total hip arthroplasty has been the most successful. Total arthroplasty operations as applied to the knee and ankle are giving promising results. These methods offer new avenues for relief of pain and deformity and stabilization of arthritic joints in the lower extremity.
Current status of total joint replacement in the upper extremity.
The principles ot total joint arthroplasty recently have been expanded to the upper extremity, following the dramatic success with total hip and total knee replacement procedures. New problems have been encountered with the rebalancing of the soft tissues and the technical nature of joint mechanics in the upper extremities. Work on shoulder joint replacement is in the very early stages and of unknown success. Several prostheses are being used and tested. For elbow and wrist replacement, early and predictable success has been accomplished, enabling relief of pain and satisfactory motion. Total joint replacement in the fingers and thumb has provided excellent relief of pain but has been hindered by difficulties in rebalancing the soft tissues in patients with rheumatoid arthritis. It appears that total reconstruction of arthritic upper-extremity joints will be commonplace in the not-too-distant future. Clinical trials are being expanded, with increasing success.
Preclinical testing of femoral hip components: an experimental investigation with four prostheses.
Existing standards for the preclinical testing of femoral hip implants have been successful in the objective of guaranteeing the implant's fatigue strength. There is a need for an experimental test which could ensure prostheses were not susceptible to aseptic loosening. In this study we measure the relative movement between the prosthesis and the bone of four different cemented femoral component designs in in vitro tests. The aim is to determine if differences can be distinguished and whether the differences correlate with clinical performance. The four designs are the Charnley (DePuy International Ltd., UK), the Exeter (Stryker Osteonics Howmedica Corp., USA), the Lubinus SPII (Waldemar-Link GmbH, Germany), and the Miiller Curved (JRI Ltd, UK). Five tests were carried out for each femoral component type, giving a total of 20 tests, and their permanent relative displacement (termed migration) and recoverable (i.e., elastic) relative displacement (termed inducible displacement) monitored over one million loading cycles. Considerable variation occurred in the tests. Nonetheless, most femoral components migrated medially, posteriorly, and distally. Most also rotated into varus. Translations of the Charnley (64 microns) and Lubinus (67 microns) implants were less than the Müller (72 microns) and Exeter (94 microns) implants, but this difference is not statistically significant. Most of the femoral components had rapid early migration followed by slower steady-state migration. With regard to the steady state inducible displacements of the prostheses, those of the Charnley, Exeter, and Lubinus decreased or were stable with respect to time, whilst those of the Müller typically increased with respect to time. It is concluded that migration is not a suitable basis for in vitro comparison of prosthesis designs. However inducible displacement trends provide a clinically comparable performance ranking.
Editorial: Replacement of the knee joint.
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Early diagnosis and treatment of steroid induced avascular necrosis of bone.
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Letter: Services available for total joint replacement.
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Arthritis as an engineering problem: Leeds and London.
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Orthopedic spinal and hip prostheses: effects of magnetic susceptibility artifacts during MR arteriography and venography of abdomen and pelvis.
PURPOSE: To retrospectively determine if susceptibility artifacts from internal metallic spinal fixation devices and hip prostheses limit the depiction of vascular anatomy and pathologic abnormalities during magnetic resonance (MR) arteriography and venography. MATERIALS AND METHODS: This study was approved by the Committee on Human Research of the Institutional Review Board, which waived the requirement for informed consent and deemed the study to be HIPAA compliant. Forty-two contrast material-enhanced MR angiographic examinations were performed by using a 1.5-T imager in 41 patients (16 men, 25 women; mean age, 57 years; range, 36-79 years); 33 of these examinations included both MR arteriographic and MR venographic components. On the basis of resolution, images for which more than 3 mm of vessels were affected by susceptibility artifacts were considered uninterpretable. The odds of obtaining an uninterpretable image due to metallic artifacts were calculated, and a chi(2) analysis was employed to determine significance. RESULTS: Total hip prostheses and spinal hardware that terminated above the L5 level did not generate any appreciable artifacts at MR arteriography (P < .001) or MR venography (P = .002). In patients with hardware that extended to the sacrum, 88% of MR arteriograms were of diagnostic quality (P = .001), but only 21% of MR venograms were interpretable (P = .004). Artifacts limited the evaluation of the inferior vena cava and common iliac veins near the confluence. CONCLUSION: Diagnostic-quality MR arteriograms and MR venograms can be obtained in patients with artificial hip prostheses and spinal hardware terminating above the L5 level, but there is 79% likelihood of obtaining a nondiagnostic MR venogram in patients with internal spinal fixation devices that extend to the sacrum.
Effect of articular disease and total knee arthroplasty on knee joint-position sense.
Joint proprioception in the human knee has been studied using two previously described tests. Threshold of detection of slow, constant, passive motion and ability to reproduce angles to which the knee was passively placed were accurately measured. A group of postoperative total knee arthroplasty (TKA) patients were examined. All patients also had documented articular disease in the unoperated knee. Results were compared to age-matched controls. In addition, a young control group was studied for comparison to both groups. A significant difference was seen between the young control group and the older control group in both tests performed. Age-matched controls and the postoperative patients demonstrated an even greater difference. There was, however, no difference between the operated and unoperated knee among the TKA patients. It is concluded that joint proprioception declines to some degree with normal aging. A more marked decline is associated with degenerative joint disease. Total joint replacement, however, did not lead to a further decrease in sensation.
Essential design considerations for microporous implants: preliminary communication.
The introduction of microporous metallic implants into which bone can grow to stabilize the implant has necessitated considerable work prior to clinical studies. Ten years of bench and animal testing have resulted in a clinically available prosthesis with a multilayer porous coating with a pore size of 50-300 mu. Initial clinical trials with a 50-100 mu hip prosthesis indicated the necessity to increase the pore size to 300 mu and clinical studies of such prostheses are at present underway.