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At least 631 records · Page 35Linked to original sources
PubMed2003

Early results of posterior-stabilised NexGen Legacy total knee arthroplasty.

OBJECTIVE: To retrospectively assess the early results of the NexGen Legacy posterior-stabilised total knee prosthesis, which is a newer version of the Insall-Burstein II posterior-stabilised implant. METHODS: 48 consecutive elderly patients had 60 NexGen Legacy posterior-stabilised total knees. The mean follow-up duration was 21 months. Clinical evaluation was performed according to the Knee Society scores and a scoring system for patellofemoral articulation; radiographic assessment followed the guidelines of the Knee Society. Special emphasis was given to any patellofemoral complications, such as patellar clunk syndrome, patellar maltracking, and other disorders of the extensor mechanism. RESULTS: Only one patient had mild patellofemoral anterior knee pain at the latest follow-up; 2 patients had patellofemoral crepitus but no pain. No patellar clunk or any other complication of the patellofemoral articulation, such as patellar fracture or subluxation was found. The mean preoperative and postoperative Knee Society scores were 60 and 85 respectively. The mean postoperative knee flexion was 115 degrees. CONCLUSION: The overall early results from using the new implant were good, probably because of changes in design of the intercondylar box and its associated cam-and-post mechanism, and a more anatomic trochlea surface, so that the trochlea accommodates the natural patella.

Aged↗
PubMed1980

Loosening of the total knee arthroplasty: detection by radionuclide bone scanning.

Pain after total knee arthroplasty is a common clinical problem in orthopedics, and prosthetic loosening, often requiring surgical revision, is usually the etiology. Since standard clinical and radiographic diagnostic measures have not proven totally satisfactory, a study of the utility of bone scintigraphy to assess stability of the knee prosthesis was done. Thirty-five patients with 39 prostheses were studied. Seventeen patients with 21 total knee arthroplasties served as controls and were asymptomatic, were stable at surgery, or improved with conservative management. Eighteen knees in 18 symptomatic patients composed the experimental group. Of these, 11 knees were loose at surgery and seven have had surgery recommended. Scintigrams of the knees were obtained using 99mTc-MDP, and ranked 0-3 corresponding to increasingly abnormal localization by three observers. Highly significant differences were observed between the abnormal and control groups (p less than 0.001). Reciprocal changes in sensitivity and specificity with increasingly stringent criteria were shown. While it is apparent that the bone scan cannot be used as the sole diagnostic method for evaluation of prosthetic stability, it does seem to be useful adjunct along with clinical criteria and radiographic studies.

Evaluation Studies as Topic↗
PubMed1997

The clinical and radiological outcome of the rotating hinged knee prostheses in the long-term.

BACKGROUND AND AIMS: Opinions about hinged knee prostheses vary a lot in different studies. We wanted to examine our series in order to gain long-term information about this kind of knee prosthesis. MATERIAL AND METHODS: Forty-eight (18 Kinematic Hinge and 30 Link Endo Model) rotating hinged knee prostheses were implanted in the Hospital of Invalid Foundation. All knees were retrospectively followed up for an average of 66.3 months and examined for clinical or radiological factors indicating the overall outcome. RESULTS: In the latest review there were 10 patients (20.8%) regarded as having unsatisfactory and 35 patients (79.2%) satisfactory results. Eighty-four per cent of the patients were subjectively satisfied with the operation, mostly because of the painless result. CONCLUSIONS: Taking into account the very poor initial status of these patients, we recommend the rotating hinged prostheses still to be used in severely instable knees awaiting revision.

Adolescent↗
PubMed1987

Unicompartmental knee arthroplasty following patellectomy.

Patients with total knee arthroplasty following patellectomy have been reported to experience pain and instability. The results of ten patients with 11 knee arthroplasties using the Marmor knee were excellent in seven patients and good in three with an average follow-up period of nine years. It is extremely important to preserve the cruciate ligaments or to use a total knee prosthesis that has inherent anteroposterior stability.

Adult↗
PubMed1993

The Oxford knee. Survival analysis of joint replacement.

To evaluate the success of a knee prosthesis, long-term follow-up studies are needed. The best means for this is survival analysis. It would be desirable for a contribution towards the costs of these essential follow-up studies to be included in the sale price of the prosthesis.

Aged↗
PubMedDate not supplied

ICLH replacement of the knee: 1977 and 1978.

Investigations which began in 1968 have culminated in a knee arthroplasty which can now be confidently used to treat most patients with arthritic knee deformities. Our earlier studies showed that a prosthetic knee arthroplasty must be reliably aligned and stabilized in extension, that patellar pain and polyethelene wear were significant potential problems and that loosening and sinkage of the tibial component must be avoided. Our present knee prosthesis and instrumentation if properly used should avoid these pitfalls. Beginning in January 1977 we performed 84 knee arthroplasties utilizing the present design. A series of 79 knees has been available for our computer-assisted review; 46 patients had a diagnosis of inflammatory arthritis and 29 had primary osteoarthrosis: 22 knees had been previously operated upon. Although all femoral components were fixed with polymethylmethacrylate, the tibial components were completely cemented in 21 knees, partially cemented in 20, and no cement was used in 38 cases. In these latter knees special pegs provided a mechanical interlock with the tibia for fixation. Thirty-six patellae were replaced, of which 11 were fixed with a similar interlocking peg. The arthroplasties failed in 8 patients. Of the remainder, 90% of knees had acceptable pain relief and all but 4 patients were able to walk outdoors. Flexion to 90 degrees or more was achieved in 85% of the knees. Only 2 patients had unacceptable alignment. To date we feel that with the use of this improved prosthesis, in conjunction with the instruments which allow proper placement of the prosthesis, the majority of arthritic knees can be successfully corrected. However, further careful long-term follow-up studies must continue.

Arthritis↗
PubMed1998

Effect of the posterior cruciate ligament in knee-joint proprioception in total knee arthroplasty.

The primary purpose of the study was to examine the role of the posterior cruciate ligament (PCL) in knee-joint proprioception after total knee arthroplasty (TKA). Knee-joint proprioception was measured in 10 patients with nonsacrificed PCL TKAs and 10 with sacrificed PCL TKAs. Knee-joint proprioception was evaluated through reproduction of static knee angles using a Penny and Giles electrogoniometer. The primary variable was absolute angular error (AAE). AAE was defined as the absolute value of the difference between the test angle and the patient's perceived version of the test angle. Proprioception deficit was compared to the WOMAC questionnaire which evaluates pain, stiffness, and physical function of the lower extremity. No significant difference was found between the nonsacrificed PCL TKA (4.33 degrees +/- 1.52 degrees) and sacrificed PCL TKA (4.38 degrees +/- 1.39 degrees) AAE values (P > .4). Furthermore, no significant differences were observed in the WOMAC questionnaire scores for all three parameters between the two types of knee prosthesis (P > .35). The current findings suggest that the preservation of the PCL in TKA may not improve knee-joint proprioception and subsequently may not improve TKA functional performance.

Aged↗
PubMed1992

Posterior stabilized prosthesis. Results after follow-up of nine to twelve years.

We reviewed, nine to twelve years postoperatively, the records on an original cohort of 289 arthroplasties (218 patients) in which a posterior stabilized knee prosthesis with an all-polyethylene tibial component had been inserted at The Hospital for Special Surgery. One hundred and eighty intact prostheses in 139 patients were available for this analysis. Fourteen knees in fourteen patients had had a revision procedure. Five of these fourteen patients had had a bilateral arthroplasty, but only one knee of each of the five patients had been revised. Forty-eight of the patients (sixty-six knees) had died less than nine years after the operation. Twenty-nine other knees (twenty-two patients) had been lost to follow-up before a nine-year evaluation could be performed. Considering all 194 knees (including the fourteen that had been revised), the result with the system of The Hospital for Special Surgery was excellent for 117 knees (61 per cent), good for fifty-one (26 per cent), fair for twelve (6 per cent), and poor for the fourteen knees (7 per cent) that had been revised. The 180 knees in which the prosthesis was intact were also rated with the new scoring system of The Knee Society: the average postoperative knee score was 92 points (range, 35 to 100 points), and the average score for function was 66 points (range, 0 to 100 points). Survivorship analysis showed that the average annual rate of failure was 0.4 per cent and that the over-all rate of success at thirteen years was 94 per cent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

Influence of minimally invasive surgery on implant positioning and the functional outcome for medial unicompartmental knee arthroplasty.

We describe postoperative functional outcome and accuracy of implant position in 38 cases after unicompartmental knee arthroplasty with the Oxford knee prosthesis with a standard open approach compared with 30 cases with a minimally invasive approach. Patients with the minimally invasive approach had significantly better functional results, with an average Hospital for Special Surgery scores of 92 (range, 81-98) compared with 78 (range, 24-99). Range of motion 1 year postoperatively was better in the minimally invasive group (113 degrees vs 107 degrees ), but the results were not statistically significant. The number of patients with extension lag was significantly higher after the open approach. The minimal invasive approach had no negative effect on positioning of the prosthesis. In our opinion, minimally invasive implantation is the method of choice for the treatment of anteromedial osteoarthritis by unicompartmental knee arthroplasty.

Aged↗
PubMed1998

Fixation of the tibial component of total knee arthroplasty after high tibial osteotomy: a matched radiostereometric study.

To assess migration of the tibial component we used roentgen stereophotogrammetric analysis in 40 patients who had had a total knee arthroplasty after failure of a closing wedge osteotomy and compared them with 40 matched patients after primary total knee arthroplasty. We found no difference in migration over time or in the tendency for continuous migration between the two groups. There were no differences in alignment or position of the knee prosthesis or in the clinical outcome. Our findings show that revision of a failed high tibial osteotomy to a total knee arthroplasty is effective.

Aged↗
PubMed2004

Cemented posterior stabilized total knee arthroplasty.

In the development of modern cemented total knee arthroplasty, the posterior stabilized knee prosthesis was designed to substitute for the function of the posterior cruciate ligament. Implant designs include the Insall Burstein posterior stabilized knee and the Legacy posterior stabilized knee. The primary feature of these prostheses is the femoral cam and tibial spine mechanism, which prevents posterior tibial subluxation and enhances knee kinematics. Another important feature is the relatively conforming round on round articular geometry that mitigates edge loading and reduces polyethylene damage. In concert, these features have produced a lineage of implants with unsurpassed clinical results, predictable kinematics and durability, which have been reproducible and well documented.

Arthroplasty, Replacement, Knee↗
PubMed1992

[The intact, injured and repaired knee: in-vitro experimental biomechanics and level walking].

In vitro simulation of knee joint movement during walking on flat ground was developed in this experimental study. Such movements are of interest for surgical and rehabilitation medicine in order to improve knowledge in the field of dynamic behavior of the knee joint during the entire range of motion: spatial kinematics and strains and stresses on the different components, in the case of intact knee, as well as of the operated one. As internal strains and stresses could not be measured directly, the aim of this experimental study was also to simulate such factors in a model using experimental input data. A simulator of joint flexion was built: it was composed of a hydraulic universal testing machine which allowed the main flexion-extension of the knee joint and an additional hydraulic device to impose the quadriceps extension force which represented the muscular action, synchronized with the imposed flexion-extension. The anatomical automatic passive rotation and valgus-varus motion were freely allowed, and these were measured during joint motion. In addition the lateral ligaments were fitted with strain sensors in order to measure their time-dependent behavior. The imposed flexion motion and quadriceps force were also measured to verify that they were accurately synchronized. The time-dependent values of force and flexion were taken from the literature. The analysis gave the mean result of eight reliable knee joint determinations: first of all intact, then after removing the anteroexternal cruciate ligaments, and finally after joint replacement by total knee prosthesis. One main conclusion was the comparison between automatic rotations, which decreased significantly after prosthesis surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed2001

Patella resurfacing in total knee replacement: functional evaluation and complications.

Three different knee replacements, with three trochlear designs, were prospectively evaluated clinically and radiographically for patellar function and presence of patellar complications. They included the Insall-Burstein (IB) I and the IB-II (posterior cruciate ligament substituting) and the Meniscal Bearing Knee (MBK; posterior cruciate ligament recession). The trochlea of the IB-I was short and shallow with an anterior sharp edge of the intercondylar box (later modified to a smoother edge) and the femoral component had a prominent "shoulder." In the IB-II the trochlea was deeper to allow for soft tissue clearance. In the MBK the trochlea was more prolonged, with R and L components and the "shoulder" was less prominent. In all the cases the patella was resurfaced with an all polyethylene dome prosthesis. Knees with tibiofemoral problems were excluded. From the data of the present study the following conclusions can be drawn: (a) The most frequent problem was impingement (clunks) with the early version of the IB-I. Smoothening of the anterior edge significantly reduced the incidence of clunks to 5% in the modified IB I. (b) With the IB-II deepening the trochlea for soft tissue clearance improved the degree, not the incidence of clunks (4.5%), compared to the modified IB I. (c) With the MBK clunks were very rare and patellar function improved. (d) Throughout the three series patellar stress fractures and instability were rare and loosening or wear not evident. (e) Normal function (including stairs ascending and descending) can be expected in over 80% of category A patients. (f) Of the various radiological parameters only patella baja was correlated with symptoms in the IB prostheses. (g) We still prefer the dome design because is more tolerant and with cold flow may better conform to the trochlea increasing contact area.

Adult↗
PubMed2004

[The minimally invasive unicompartmental knee system "Preservation"First clinical results and analysis of complications].

The Preservation uni knee system is a minimally invasive procedure for implantation of a unicompartmental knee prosthesis. The early results show that the rehabilitation process is quick; the postoperative pain and blood loss is less than after conventional knee arthroplasty. Still there are some pitfalls. The implantation of the tibial mobile-bearing component requires a sound operative technique; otherwise complications will occur. The combination of the available navigation system with the Preservation uni will improve operative accuracy.

Aged↗
PubMed2003

Long-term results of low contact stress mobile-bearing total knee replacements.

Five hundred ninety-eight consecutive primary low contact stress total knee replacements were done in 502 patients between 1985 and 1990. Clinical review was available for 495 knees (406 patients), 228 knees with meniscal-bearing prostheses and 267 knees with rotating-platform prostheses. The average followup was 12 years (range, 10-15 years). The average postoperative knee and functional scores were 87 points and 75 points, respectively. The average postoperative range of motion was 110 degrees. Fifty-six knees (11%) required revision for excessive wear of the tibial insert (41), dislocation (10), patellar polyethylene breakage (one), component loosening (one patellar, one tibial), and infection (two). During revision, osteolysis (20 knees), patellar polyethylene failure (33), and femoral component fracture (one) were seen. The overall survivorship was 88.1% at 15 years using Kaplan-Meier analysis. The survival rate was 83% for the meniscal-bearing prostheses and 92.1% for the rotating-platform prostheses. The Low Contact Stress mobile-bearing knee prosthesis has no superiority over that of fixed-bearing knees, especially for the meniscal-bearing design in prevention of polyethylene failure or revision. Based on the results of this study, the use of the LCS meniscal-bearing prosthesis does not appear to be justified.

Adult↗
PubMed2003

Reliability of templating in estimating the size of uni-condylar knee arthroplasty.

The use of template systems has aided the preoperative selection of correct prosthetic size during routine arthroplasty. A similar system exists for unicondylar knee arthroplasty. Our goal is to assess the reliability of these templates for preoperatively predicting the correct prosthetic size in unicompartmental knee systems. Ten observers estimated the size of the unicondylar knee prosthesis required for 30 randomly selected patients with osteoarthritis. Estimation of the size was gauged using templates and instructions provided by the manufacturer. The observers worked independently and repeated their measurements 2 weeks later. Intraobserver and interobserver agreement was evaluated using the weighted kappa coefficient, and this revealed poor agreement regardless of the surgeon's experience. This shows that the present system lacks reliability and raises concerns about the place for preoperative radiological templating in unicompartmental knee arthroplasty.

Femur↗
PubMed2003

The Hospital Infection Standardised Surveillance (HISS) programme: analysis of a two-year pilot.

In 1998 the New South Wales (NSW) Health Department funded the development and implementation of the State's first standardized methodology for the surveillance of healthcare-associated infection for public hospitals. Fifteen pilot hospitals targeted inpatient groups considered to represent their core patient groups to act as sentinel measurements of patient safety. The aggregated rates of surgical site infection for coronary artery bypass graft (CABG) (chest & leg) surgery was 1.7% (95%CI: 1.1-2.5), CABG (chest only) 2.1% (95%CI: 1.0-3.7), vascular 7.1% (95%CI: 4.6-10.3), hip prosthesis 1.3% (95%CI: 0.5-2.7), knee prosthesis 6.1% (95%CI: 2.8-11.2) and colorectal 12.5% (95%CI: 9.5-16.1). The development of a bloodstream infection (BSI) associated with a central venous catheter (CVC) was not significantly (P=0.6) different when examined by duration of exposure with 3.7 BSI per 1000 line-days for CVC in situ six or more days compared with 4.0 BSI per 1000 line-days for CVC in situ for five or less days. A significantly (P<0.0001) greater proportion of patients whose CVC was in situ six or more days (6.8 per 100 patients, 95%CI: 4.2-10.2) developed a BSI compared with the proportion of patients whose CVC was in situ for five or fewer days (0.6 per 100 patients, 95%CI: 0.3-1.3). Significantly (P<0.0001) different rates of patients acquiring a new methicillin-resistant Staphylococcus aureus infection were found when hospital type was examined with rates ranging from 0.2 to 5.0 per 10000 occupied acute-care bed-days. The pilot highlighted that the collection of data for aggregation of some procedures and intravascular catheters may take many years before a reliable benchmark can be identified and many hospitals may not achieve reliable local rates annually. For surveillance to provide timely measures of patient safety we should consider surveillance methods for many small to medium sized hospitals that includes active surveillance only for infections with concurrent passive surveillance of the relevant denominators.

Catheterization↗
PubMed2002

Supracondylar fractures of the femur above total knee arthroplasties with cortical allograft struts.

Ten supracondylar fractures of the femur above a total knee arthroplasty were treated with open reduction and internal fixation using a metal plate and cortical allograft struts. Failure with nonunion of previous operative treatments was seen in 5 patients. The other 5 patients had either severe osteopenia or comminution of the fracture above the knee prosthesis. At an average of 38 months' follow-up, all the fractures healed with an average union time of 17.6 weeks. The postoperative knee alignment averaged 5.1 degrees valgus. Infection occurred in 1 patient, which resulted in a poor outcome. The remaining 9 patients were functioning well at the most recent follow-up examination. The use of cortical allograft struts combined with a compression plate provided satisfactory results for supracondylar fractures above knee prostheses with severe osteopenia or loss of bone stock after initial failure of internal fixation.

Aged↗