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At least 55 records · Page 3Linked to original sources
PubMed2000

Ten- to 12-year followup of the Insall-Burstein I total knee prosthesis.

The Insall-Burstein Posterior Stabilized knee prosthesis (Insall-Burstein I), developed at The Hospital for Special Surgery in 1978, has a metal-backed nonmodular tibial component. The polyethylene articular surface was directly molded. The purpose of the current study was to evaluate long-term wear with this design. The first 100 total knee arthroplasties (86 patients) performed by the senior author were followed prospectively. The average age of the patients at the time of surgery was 69.7 years (range, 45-89 years). The primary diagnoses were osteoarthritis in 77 knees (66 patients), inflammatory arthritis in 17 knees (14 patients), and posttraumatic arthritis in the remaining six knees (six patients). Thirty-eight knees (35 patients) had varus angulation, 14 knees (13 patients) had valgus angulation, and 48 knees (40 patients) had a 0 degrees to 10 degrees tibiofemoral angle preoperatively. All patients were evaluated at 10 to 12 years followup. Knee Society scores and radiographs were obtained. Thirty-six knees were in 30 patients who had died and two knees were in two patients who were infirm. Telephone evaluation only was available for eight knees (seven patients), leaving 54 knees (47 patients) for direct clinical and radiographic evaluation. No patients were lost to followup. The average Knee Society clinical score at latest followup was 91.6 points. The average function score was 69 points. One knee arthroplasty failed because of tibial loosening, one failed because of patella wear and fracture, two failed because of sepsis, and two failed because of nonspecific pain. There were seven patella fractures (7%) in the 100 knees. One of the fractures resulted in a total knee revision (noted above), two resulted in patellar component revision, and another resulted in patellar component removal. The remaining three patella fractures were discovered incidentally and were asymptomatic. There were no patellar dislocations. At long-term radiographic analysis, valgus alignment averaged 6 degrees (range, 0 degrees-11 degrees). Polyethylene wear averaged 0.40 mm. There was no catastrophic wear of tibial polyethylene. Thirty-two knees in 32 patients (65%) had radiolucencies in at least one zone; no lucency filled a zone, and none was wider than 2 mm. The absence of clinically significant tibial polyethylene wear at long-term followup is of particular interest. The performance of the molded, nonmodular polyethylene articulation is encouraging and needs to be analyzed critically against the more widely used machined, modular components used today.

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PubMed1997

Reduction of polyethylene in a congruent meniscal knee prosthesis. Experimental and clinical studies.

Polyethylene wear was assessed in the Rotaglide congruent meniscal bearing total knee prosthesis and a partial congruent total knee prosthesis with fixed bearing polyethylene tibial platform and a posterior stabilizer mechanism. A special wear test rig was used to test the 2 prostheses under compression load of 2960 N/mm2 (about 4 times the average body weight) and continuous 0 degree-70 degrees flexion-extension motion at the rate of 1 cycle per second. The most remarkable finding was the lack of measurable wear on the Rotaglide meniscal bearing up to 3.5 million cycles, while the other prosthesis began to show wear from the first million cycles and progressed to 0.38 mm at about 3.5 million cycles. At 11 million cycles (about 20 years of life), the Rotaglide showed penetration wear of 0.35 mm compared to 2.1 mm in the other prosthesis. In 7 meniscal bearings, retrieved either at postmortem (2) or at reoperation (5), no measurable penetration wear was observed after 3 years of implantation. Only 1 prosthesis obtained 5 years after implantation showed 0.23 mm penetration wear or about 0.05 mm per year. These findings strongly suggest that the use of congruent meniscal bearing prosthesis can reduce the polyethylene wear in total knee replacement.

Arthroplasty, Replacement, Knee↗
PubMedDate not supplied

e-Knee: the electronic knee prosthesis.

Tibiofemoral forces determine polyethylene wear and affect the longevity of total knee prostheses. Previously, investigators relied on theoretic data from mathematical models to predict mechanical forces in the knee. Predictions of tibiofemoral forces are highly variable because of the complex interplay of the muscles involved in activities. Ideally, knee forces should be directly measured. An electronic total knee prosthesis (e-Knee) was developed to directly measure tibiofemoral compressive and tensile forces in vivo. After 13 years of research and development, the e-Knee was implanted into a patient in 2004. Tibiofemoral force data were collected intraoperatively and throughout the postoperative period during activities of daily living and during exercise. Direct measurement of knee forces can lead to a better understanding of the stresses seen following total knee arthroplasty. Information generated by the e-Knee will aid in the improvement of implant design and patient care.

Activities of Daily Living↗
PubMed1983

Biomechanics of the through-knee prosthesis.

The biomechanics of the through-knee prosthesis is considered in detail and comparisons made with the above-knee case. Socket shape and suspension are discussed and comment offered on knee function in both stance and swing phases.

Amputation Stumps↗
PubMed1991

Analysis of a new polycentric above-knee prosthesis with a pneumatic swing phase control.

The four-bar linkage mechanism used by many designers for the knee joint of an above-knee prosthesis can provide knee rotation suitable for walking only. In Afro-Asian countries people are habituated to the squatting posture in their daily activities. A six-bar linkage knee-ankle mechanism above-knee prosthesis with a pneumatic swing phase control is developed and its analysis shows its suitability for producing a motion closely resembling that of a normal subject during walking and squatting.

Ankle Joint↗
PubMed1991

A long-term follow-up study of unicompartmental replacement with a Marmor knee prosthesis and the introduction of a new ceramic prosthesis.

Unicompartmental replacement with a Marmor knee prosthesis was performed in 53 patients with unicompartmental osteoarthritis (OA). A five year or longer follow-up study of 15 joints in 13 of these patients was possible, three of which are now more than 10 years post-operative. All 13 patients reported absence of pain on weight-bearing and were able to flex the replaced knee more than 105 degrees. However, the postoperative femorotibial angle (FTA) appeared to be worsening with time, especially in those cases with an immediate postoperative FTA of more than 180 degrees. Since the needed size of the Marmor prosthesis is no longer available, we began using a ceramic prosthesis recently which we are introducing in this article.

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PubMed1995

An above-knee prosthesis with a system of energy recovery: a technical note.

Knee flexion to 24 degrees during early stance transforms kinetic energy into potential energy of a total center of mass (TCM) position. Flexion is controlled by the musculoligamentous apparatus. Reproduction of such flexion in a new single-axis prosthesis knee unit has minimized the metabolic energy cost to the patient by a more favorable use of gravity acting upon the prosthetic segments and the body as well as of inertia. Potential energy is stored in the spring shock absorber of the knee unit. The coefficient of energy recovery increased by 30% in comparison with a conventional above-knee prosthesis. Energy costs to the patient decrease an average of 35% during gait with the new prosthesis. The same amount of unloading during walking is typical of an intact limb. The knee unit mechanism has a link set on the axle, thus providing two joints with a common axis: a) the main joint for knee flexion to 70 degrees during swing phase and flexion to 135 degrees during sitting; b) the second joint for bending at the beginning of stance phase. Compared with conventional units, gait with the new unit displays several functional advantages: 1) normal knee kinematics with movement of a TCM along a trajectory that contributes to an easy rollover of the foot and smooth and continuous translation of the body; 2) shock absorption during early stance prevents impact from the anterior brim of the socket; 3) at mid-stance, the increase of the TCM position accumulates potential energy that results in a significant increase of the push-off force; 4) during rapid gait, the unit provides adequate resistance to knee flexion; 5) location of the joint axis in front of the line of gravity loads the prosthesis in standing, making possible unimpeded carrying of the prosthesis over the support, the lengths of the prosthetic and the intact limb being equal; in addition, it facilitates flexion before the beginning of the swing phase. Production of the units began in 1992.

Amputation Stumps↗
PubMed1975

Performance analysis of an ex vivo geometric total knee prosthesis.

Studies were made of a well functioning geometric total knee prosthesis, removed at autopsy from a sixty-one-year-old man, which had been used for eight months. The components were firmly embedded in bone with no evidence of loosening. There was significant deformation of the polyethylene tibial component, but no significant wear on the metallic component. Thin layers of fibrous tissue were found in some areas of the bone-cement interfaces.

Acrylates↗
PubMedDate not supplied

[Single compartment Oxford knee prosthesis].

From 1988 to 1992, we implanted 30 Oxford single compartment prostheses. Follow-up was sufficient for study in 27 cases. The Oxford single compartment prosthesis is original because the height of the meniscal component varies with mobility during flexion-extension. This single compartment prosthesis requires a rigorous technique on the basis of well respected fundamental principles. The opposite femorotibial compartment must be untouched, otherwise a slight deviation of the axis may occur. Mobility must be satisfactory and the anterior cruciate ligament must not be injured. In our series, we obtained the same results as published in the literature, particularly those reported by Goodfellow who advocates its use. Results were satisfactory in 89% of the patients. There was an extraordinary improvement in pain symptomatology. There was little improvement in mobility. Overcorrection must be absolutely avoided because of the risk of destroying the opposite compartment. Besides the classical complications which include thrombophlebitis and retarded scar formation, we noted 3 luxations of the meniscus, 2 involving the medial meniscus and 1 the lateral meniscus. In 2 cases we had to change the meniscus (once under general anaesthesia) and in 1 cases had to reoperate to install a total prosthesis. The Oxford single compartment knee prosthesis is an important implant which has its place between osteotomy and a total prosthesis, when used according to rigorous technique. There is nevertheless the risk of meniscal luxation with this type of prosthesis.

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