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PubMed1997

Application of numerical descriptors to the characterization of wear particles obtained from joint replacements.

The application of image analysis techniques to the characterization of wear particles from failed joint replacements has been described. Wear particles were extracted from periprosthetic tissues collected during revision surgery. Chemical digestive methods were used to separate the wear particles from the biological soft material. The particles isolated were examined by optical and scanning electron microscopy. Digitized particle images were analysed on a Macintosh computer by a specially developed software and by the image analysis program 'Prism'. The following numerical descriptors were used to characterize the particles: particle size, boundary fractal dimension and shape parameters such as form factor, roundness, convexity and aspect ratio. Elemental composition of the particles was determined by energy dispersive X-ray spectroscopy. Three selected types of wear particles were analysed and compared: titanium (Ti)-based and calcium (Ca)-based particles from a hip prosthesis and ultra-high molecular weight polyethylene (UHMWPE) particles from a knee prosthesis. The particles exhibited significantly different sizes and their shape numerical descriptors were also different. From the results obtained it appears that computer image analysis of wear particle morphology can be employed to determine the wear processes occurring in the joints. In some cases, the condition of the joint can also be assessed based on this analysis.

Fractals↗
PubMed1985

Energy cost during gait in osteosarcoma patients after resection and knee replacement and after above-the-knee amputation.

We determined the energy cost during gait by measuring the oxygen consumption of twenty-six patients after treatment for osteosarcoma about the knee. Fourteen had had an en bloc resection of the distal end of the femur and proximal end of the tibia followed by segmental replacement with a custom-made knee prosthesis and twelve had had an above-the-knee amputation followed by fitting with an artificial limb. Comparisons of free-walking velocity, oxygen consumption per meter traveled, and per cent of maximum aerobic capacity used during walking demonstrated that patients with resection and prosthetic knee replacement had a lower energy cost during gait.

Adolescent↗
PubMed2001

Knee reconstruction with prosthesis and muscle flap after total arthrectomy.

A massive prosthesis and medial gastrocnemius muscle transfer were used to reconstruct the knee after extracapsular en bloc excision for bone sarcoma. Magnetic resonance images showed intraarticular involvement. This technique was used in nine patients, six men and three women aged 18 to 51 years, with primary malignant bone tumors of the knee. Extraarticular resection of the knee, including the patella, was done in every case. A knee prosthesis was implanted, and the extensor mechanism was reconstructed by transfer of the medial gastrocnemius muscle and pes anserinus tendons. All resections had negative margins. There were no local recurrences, but metastases occurred in two patients. Infection was the only major complication and was seen in two patients. The mean postoperative Musculoskeletal Tumor Society score was 61% (range, 36%-100%). The mean postoperative range of flexion was 62 degrees (range, 30 degrees-90 degrees), and the mean extensor lag was 12 degrees (range, 0 degrees-40 degrees). Three patients required a crutch to walk. The functional outcome was poor in the two patients whose proximal tibia was removed with the joint, suggesting that arthrodesis may be best in this situation. In properly selected patients, prosthesis and muscle flap reconstruction provides acceptable function and a good cosmetic result.

Adolescent↗
PubMed1989

Porous-coated knee arthroplasty. A case report concerning bone ingrowth.

The area of bone-metal interaction in uncemented implants is regarded by many investigators as the key to the success or failure of the implant. The nature of the interaction is poorly understood because the zone is technically difficult to visualize and analyze. In order to test the power of modern imaging, analyzing, and metallurgical methods in this context, a well-functioning porous-coated knee prosthesis (tibial component) removed from the knee of a 65-year-old man was sectioned and examined by light microscopy, roentgenogram, scanning electron microscopy, and radiologic energy dispersive analysis. Independently, these methods demonstrated that the prosthesis was held in situ by collagenous tissue between and below the metal pellets of the prosthesis. Calcified bone did not appear to interact with the prosthesis and is probably not a major factor for prosthesis fixation. The various analytic methods described are suitable and sufficient for further exploration on a larger scale of the zone of bone-metal contact in cementless implants.

Aged↗
PubMed2001

Computer-assisted implantation of total knee prostheses: a case-control comparative study with classical instrumentation.

A navigation system should improve the quality of a total knee prosthesis implantation in comparison to that obtained with the classical, surgeon-controlled operative technique. The authors implanted 30 total knee prostheses with an infrared navigation system (Orthopilot, Aesculap, Tuttlingen, Germany). The quality of implantation was studied on postoperative long-leg coronal and lateral X-rays, and compared to a control group of 30 matched-paired total knee prostheses of the same type (Search prosthesis, Aesculap, Tuttlingen, Germany) implanted with a classical, surgeon-controlled technique. An optimal mechanical femorotibial angle (177 to 183 degrees) was obtained in 25 cases in the study group and 21 cases in the control group (p > 0.05). Similar differences were seen for the coronal and sagittal orientations of both tibial and femoral components. Globally, 23 cases in the study group and 8 cases in the control group were implanted in an optimal manner for all studied criteria (p < 0.001). The navigation system used allows a significant improvement in the quality of implantation of a total knee prosthesis in comparison to that obtained with a classical, surgeon-controlled instrumentation, and long-term outcome could consequently be improved.

Aged↗
PubMed2000

Survival of cementless and cemented porous-coated anatomic knee replacements: retrospective cohort study.

AIM: To evaluate the effect of cement use in porous-coated anatomic (PCA) total knee prosthesis on its survival. METHODS: The study was a retrospective analysis of 142 PCA total condylar arthroplasties performed in 124 patients from 1985 to 1991. Uncemented prostheses were used in 87 knees, the prostheses were cemented in 44 knees, and hybrid prosthesis components were used in 11 knees. The average follow-up time was 88 months (range 66-140). The survival of prosthesis was assessed using the Kaplan-Meier's method. The Baltimore score was evaluated as a measure of clinical performance in 115 replacements. RESULTS: The overall cumulative survival rate of a PCA total knee prosthesis was 77% over the average follow-up period of 88 months. No significant differences in survival rates among cementless, cemented, or hybrid fixations could be demonstrated. The survival rate of the prostheses in patients with rheumatoid arthritis (82.5%) was significantly higher than in patients with osteoarthritis (73.8%). Revision was necessary in 29 (20.4%) replacements. CONCLUSION: The survival of PCA endoprosthesis, regardless of the components used for implantation, is not satisfactory.

Adult↗
PubMed2002

Denham total knee arthroplasty: a 10-year follow-up study.

We reviewed 72 patients with 89 Denham total knee arthroplasties (Biomet, Warsaw, IN) (TKAs) 10 to 15 years after the operation. Of 8 TKAs that were considered as failures, 5 had been revised at the time of review for pain and aseptic loosening, and 3 others were considered to have failed because of breakage of the polyethylene tibial plateau, dislocation, and infection. Survival analysis suggested a 10-year survival rate of 92.7%. There were 36 patients with 45 TKAs alive at the time of follow-up. We reviewed 32 of the patients with 40 Denham TKAs that had not failed. Their average age was 81 years (range, 58-93 years). They were reviewed at an average of 11.8 years after TKA. Nine knees (6 patients) had some anterior knee pain from the unresurfaced patella. Restriction of function was mainly due to medical conditions and old age. Survival analysis performed with the living patients found the 10-year survival to be 91.1%. Long-term survival shows that the Denham knee prosthesis is effective despite its simplicity.

Adult↗
PubMed1984

[Phlebography after total prosthesis. Action of subcutaneous sodium heparin in the prevention of thromboembolism. Results of therapeutic research with subcutaneous sodium heparin using 2 protocols in 250 patients monitored with phlebography].

Two series of patients on which total hip or knee prostheses had been inserted were studied. In the first series (150 cases), the patients were treated with low molecular Dextran and subcutaneous sodium heparin at a constant dosage. The Howell test was done every 3 days. The rate of post-operative thrombosis was 14 p. 100. In the second series (100 cases), the patients were treated with low molecular Dextran and subcutaneous sodium heparin with a variable dose adapted to the type of patient. The rate of post-operative thrombosis was only 7 p. 100. The insertion of a knee prosthesis was much more thrombogenic than hip prostheses. In the second series the rate of thrombosis after hip surgery was only 2 p. 100. However a number of complications relating to anticoagulation were a limiting factor of the method.

Clinical Trials as Topic↗
PubMed1994

The excursion length of posterior cruciate ligament during range of motion in prosthetic knee.

Restriction of knee motion after total knee replacement was noted to be associated with lengthening of the posterior cruciate ligament during flexion of the knee which was replaced with a cruciate retaining knee prosthesis. The purpose of this study was to measure the excursion length of the PCL in the normal knee in four different cruciate-retaining knee prostheses, and in five cadaveric knees which were replaced with the Tricon prosthesis. For every knee, the tibial part was fixed on a stand and the femoral part was allowed to do flexion-extension motion upon the tibial plateau. The angle of the motion was monitored by the self-readout goniometer. A thin wire cord was attached to the proposed origin site of the PCL on the femur. The wire cord was passed through a tiny hook which was attached to the proposed insertion site of the PCL on the tibia and connected to a dial gauge. The excursion length of the PCL during 90 degrees flexion was measured. The same measurement was repeated five times in each cadaver knee and prosthetic knee studied, and in five knee specimens which were replaced with the Tricon prosthesis. The excursion length of the PCL during 0 degrees to 90 degrees of flexion in five cadaver knees averaged 0.08cm of lengthening. Three different origin sites of the ligament were designated to represent the anterior, middle and posterior part of the ligament.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed2002

Acute renal failure after local gentamicin treatment in an infected total knee arthroplasty.

Local gentamicin treatment in revision surgery for infected hip and knee prostheses is well established. It is a safe and effective method compared with the systemic use of aminoglycosides. Although nephrotoxic side effects are uncommon, we report a case of acute renal failure after 2-stage revision treatment of an infected knee prosthesis with gentamicin-impregnated beads and block spacers. The combined use of beads and a cement block spacer, both gentamicin impregnated, may have induced this severe complication. Use of this procedure in elderly patients warrants careful follow-up of renal function.

Acute Kidney Injury↗
PubMed1986

Roentgenographic evaluation of geometric total knee arthroplasty with a six-year average follow-up period.

The geometric total knee prosthesis was used in the reconstruction of 70 damaged knee joints in 56 patients from November 1973 through March 1979. The average follow-up period extended to six years and seven months. Eleven patients had died and four could not be located. Eighty-one percent of the remaining knees had little or no pain at the time of the review. Pain in the patellofemoral joints was an insignificant problem in this series. The femorotibial shaft angle ranged from 0 degrees to 10 degrees of valgus in 43 (82.7%) of 52 knees. Six knees showed varus deformity at the time of follow-up examination. Stress fracture of the medial condyle of the tibia was found in two of these six knees. The absence of a radiolucent zone at the tibial cement-bone interface was noted in only ten (19.2%) of the 52 knee roentgenograms. New formation or progression of a radiolucent zone from six to 12 months after the operation was found in 36.5%. Positional abnormality of the marker wires seen in serial roentgenograms existed in 51.9% of the knees. Nine knees (17.3%) disclosed a gap between the metallic articular surface and the tibial component and also showed the collision of the tibial intercondylar eminence against the femur in the standing position. The tibial component of the prosthesis was fractured in one knee.

Adult↗
PubMedDate not supplied

[Revision interventions in aseptic and infected loose knee endoprostheses].

From 1984 to 1988 20 revisions for aseptic or septic loosening of knee prosthesis were performed. In 12 case there was an aseptic- and in 8 cases a septic loosening of the prosthesis. Most revision surgery for loosening of knee replacement needs reconstruction of bone stock. In loosening of unconstrained knee prostheses (uni-, totalcondylar knees) it was possible to insert a total condylar knee for revision surgery. Partially gross deviations had to be corrected, but in all cases a good alignment and ligamentous stability were effected. In septic loosening we had good experience with the two stage procedure. We temporarily implanted a gentamycine-PMMA-Spacer to avoid soft tissue contracture and to inhibit fusion of the cancellous bone. Arthodesis after knee replacement is difficult to manage, because the sclerotic bone of the site the prosthesis doesn't easily fuse.

Anti-Bacterial Agents↗
PubMed2000

The Bisurface total knee replacement: a unique design for flexion. Four-to-nine-year follow-up study.

BACKGROUND: The Bisurface knee prosthesis was designed in 1989 to improve knee flexion without affecting the durability of the prosthesis. The prosthesis has a unique ball-and-socket joint in the midposterior portion of the femoral and tibial components, which functions as a posterior stabilizing cam mechanism and causes femoral rollback. The femoral component was made of alumina ceramic. The purpose of this study was to review the clinical results of the first 223 arthroplasties performed with this prosthesis in order to assess whether this new implant had achieved its design objectives. METHODS: From December 1989 to May 1994, all patients who were scheduled for primary total knee arthroplasty were enrolled in a prospective study of the Bisurface knee. The patients were evaluated clinically according to The Hospital for Special Surgery knee-rating system and with a self-administered questionnaire, and they were evaluated radiographically according to the system of the Knee Society. Kaplan-Meier survivorship analysis was performed with revision of the knee or recommendation for revision as the end point. RESULTS: One hundred and sixty-six patients treated with a total of 223 consecutive primary total knee arthroplasties were enrolled in the study, and 182 knees were followed for 3.9 to 9.0 years (mean, 5.8 years). Preoperatively, the mean Hospital for Special Surgery knee score was 44.5 points. At the time of latest follow-up, the mean knee score was 86.3 points. The mean preoperative and postoperative ranges of flexion were 119 and 124 degrees, respectively. The patients, even those with a good preoperative range of motion, rarely lost deep flexion of the knee after the procedure. A revision operation was performed in eight knees (because of infection in five, instability in two, and breakage of the peg of the patellar component in one). Two knees had recurrent medial-lateral subluxations of the femorotibial articulation, which were treated nonoperatively. No prosthesis had loosened aseptically and no alumina ceramic femoral component had broken by the time of latest follow-up. The rate of survival of the implant was 94 percent (95 percent confidence interval, 90 to 98 percent) at six years. According to the patient questionnaires, 20 percent of the knees sometimes felt loose in daily living activities, which prompted us to improve the intrinsic stability of the prosthesis by improving the congruity of the ball-and-socket joint. CONCLUSIONS: Total knee arthroplasty with the Bisurface prosthesis resulted in an excellent range of motion and a high level of satisfaction with the operation; the durability of the prosthesis is promising.

Aged↗
PubMed2005

Revision of the Sheehan total knee arthroplasty.

The use of the Sheehan knee prosthesis extended from 1971 to 2002. It incorporated a semi-constrained hinge with intra-medullary stems cemented into the femur and tibia. While some authors have reported excellent short-term results, others have reported revision rates of up to 31% at 5--10 years. The aim of this study was to review the senior author's experience in revising these arthroplasties. We review 54 Sheehan total knee replacements and discuss the difficulties encountered during first and subsequent revisions and the often-complex reconstruction techniques used to overcome these.

Adult↗
PubMed1995

Evolution of the quadriceps snip.

Between May 1990 and December 1992, the quadriceps snip was used to assist in the surgical exposure of the knee in 16 patients (4 women and 12 men) who underwent knee surgery at the average age of 65 years (range, 50-73 years). The original diagnoses included osteoarthritis (12 patients), traumatic arthritis (2 patients), rheumatoid arthritis (1 patient), and psoriatic arthritis (1 patient). The surgical exposure was done in the treatment of aseptic loosening of a total knee prosthesis in 8 patients, septic loosening in 2 patients, and primary knee arthroplasty in 6 patients with fibrous ankylosis. Using the Hospital for Special Surgery Scoring System, the authors rated the knees of 10 patients as excellent and those of 6 patients as good at postoperative evaluation. The range of motion was improved in all knees by an average of 30 degrees. Cybex testing revealed significant weakness of the knee in extension when compared with the contralateral normal side at test speeds of 60 degrees and 180 degrees per second but no difference compared with the opposite knee that had been replaced. In the authors' experience, the surgical technique of a quadriceps snip has been safe and simple, has not required special equipment, and postoperatively the patient's physical therapy has not had to be altered. Clinically, the quadriceps strength was very good, although weaker than that of a contralateral normal leg when measured by Cybex testing.

Aged↗
PubMed1986

The total condylar prosthesis.

Forty knees with total condylar prostheses have been followed for ten years or more. There were five failures, one due to infection and four directly related to either improper selection or technical reasons. Thirty-five knees (87.5%) have a satisfactorily functioning arthroplasty after ten years. There were no loose components and no complete radiolucent lines. Technique and correct alignment are most important and, provided that the operation is correctly performed, conventional polymethyl methacrylate cement fixation is completely adequate. The absence of progressive adverse radiologic changes suggests that knee arthroplasties have a considerable life expectancy.

Aged↗
PubMed1999

[Computer-assisted preoperative planning of knee replacement arthroplasty].

UNLABELLED: The general configuration of replaced knee is difficult to anticipate because of the large number of geometrical parameters related to morphology, prosthetic implants and pre-operative choices (such as ligament release). This article features the studies achieved in order to create a decision aiding computer tool dedicated to total knee prosthesis. METHOD AND MODEL: We have built a geometrical modelling of the physiological knee and prosthesis elements association. A numerical processing through biomechanical laws permitted to simulate the geometrical and mechanical behaviour of the whole for different flexing angle. RESULTS: A first validation of the model, comparing the numerical simulation results and the measuring of the 30 implanted knee X-rays, showed a valid matching (86 p.cent of the total cases) between model and real configuration. DISCUSSION: This tool allows to realise simulations and optimizations with regard to the following issues: decreased risks of the unsealing of the patellar component through contact centering with the trochlea, increased mechanical efficiency of the force transmission from the quadriceps to the tibia, increased maximum flexing angle considering the extension of the quadriceps. CONCLUSION: The orthopedic surgeon should be greatly assisted in the future preoperative planning by these initial findings.

Arthroplasty, Replacement, Knee↗