Midterm clinical and radiographic results with the genesis I total knee prosthesis

Genesis 1 posterior cruciate-retaining total knee arthroplasty with asymmetric tibial tray: An 18-to-26-year long-term clinical outcome study

BACKGROUND

To present the long-term clinical and radiological outcomes of the Genesis I posterior cruciate-retaining total knee arthroplasty (TKA) (Smith & Nephew Orthopaedics, Memphis, TN, USA) (one of the first designed with an asymmetric tibial tray).

METHODS

Prospectively collected data from 117 cemented TKAs performed on 95 patients were evaluated using this design, with a mean follow-up of 21.5 years (range, 18-26). Failures, complication rates, and clinical (both subjective and objective) and radiological outcomes were assessed for all patients.

RESULTS

Seven failures occurred (wear and structural failure of the polyethylene insert) and six revision surgeries were performed at a mean of 10 years (range, three to 14) from the index operation. No revision of either the femoral or tibial components for aseptic loosening was performed. Survivorship analysis showed a cumulative success rate of 93.53% (95% CI, 92.75-94.32%) at 20 and 25 years, with revision for any reason as an end point. All patients showed a statistically significant improvement (P = 0.001) in the Knee Society and Oxford knee rating scores.

CONCLUSIONS

This study demonstrated satisfactory long-term clinical outcomes for this TKA design, with revisions being related to polyethylene wear structural failure.

Safety and efficacy of a rotating-platform, high-flexion knee design three- to five-year follow-up

Our hypothesis was that a high-flexion rotating-platform posterior stabilized (RP-PS) design could maximize range of motion (ROM) and improve deep-flexion activities. Eighty-seven consecutive patients (109 knees) with high-flexion RP-PS design were prospectively followed up for a minimum of 3 years. Radiographic and clinical outcomes were analyzed using Knee Society Score criteria and Western Ontario and McMaster Universities Osteoarthritis Index. Good to excellent clinical scores were achieved in 96% of the knees. There were no cases of infection, malalignment, loosening, osteolysis, or spinout. The mean preoperative ROM improved from 110.7° to 124° postoperatively. High-flexion activities such as squatting and kneeling were achieved in 62% and 60% of patients, respectively. High-flexion knee implant is safe and improves ROM and deep-flexion activities. Persistent pain is an important cause of dissatisfaction after total knee arthroplasty.

Long-term results of posterior-cruciate-retaining Genesis I total knee arthroplasty

BACKGROUND

Long-term results of Genesis I modular total knee system are not well known.

METHODS

We analyzed data from 345 patients with 393 primary total knee arthroplasties (TKA) using the Genesis I prosthesis. In all cases, the posterior cruciate ligament (PCL) was retained, and the patella was not resurfaced. The minimum follow-up was 10 (range 10-16) years.

RESULTS

Preoperative range of motion improved from 89° preoperatively to 105° at the time of the most recent follow-up (p < 0.001). Mean preoperative Knee Society pain and function scores increased from 29 and 25 points to 91 and 85 points, respectively (p < 0.001). Tibiofemoral angle shifted from 2.40° of varus before to 4.8° of valgus after the operation (p < 0.001). Early postoperative complications occurred in 34 knees (8.6%). Manipulation under general anesthesia was done in six knees (1.5%). Nonprogressive radiolucent lines were seen around the femoral component in 16 knees (4%) and at the tibial bone-cement interface in 101 knees (25%). However, in only five cases (1.3%) was there significant progression leading to implant loosening and revision surgery. Eight more revisions were performed due to infection (three knees), stiffness (three knees), excessive wear and fracture of polyethylene liner (one knee), and instability (one knee). The overall survivorship of knee replacement reached 96.7%.

CONCLUSIONS

In the long term (up to 16 years), PCL-retaining Genesis I total knee prosthesis is associated with good functional outcomes and low failure rates.

The EUROP total knee prosthesis: a ten-year follow-up study of a posterior cruciate-retaining design

INTRODUCTION

The success of total knee arthroplasty is measured by pain relief, functional recovery, and implant survival duration. The aim of the present study was to evaluate the long-term clinical, functional and radiological results of the posterior cruciate ligament (PCL)-retaining fixed bearing EUROP implant.

HYPOTHESIS

The long-term results of EUROP implants are similar to those reported with comparable prostheses.

PATIENTS AND METHODS

We performed a prospective, monocentric study of a series of 121 cemented EUROP total knee arthroplasties, implanted between 1994 and 1996 in 117 patients mean age 73. A clinical and radiological evaluation was performed at 10 years of follow-up according to the International Knee Society (IKS) score. Twenty-three patients died, 14 were lost to follow-up, 43 underwent clinical and radiological evaluation and 37 were questioned by telephone.

RESULTS

The preoperative IKS knee score was 31 points (0-60) and increased to 88 points (30-98) at final follow-up, IKS function increased from 40 (0-90) to 80 points (25-100). Radiolucencies were observed in 56% of the condyles and 60% of tibial plates. Ninety-three percent of these radiolucent lines were less than 1mm wide. Three patients underwent revision TKA at 32 months, eight and 11 years respectively. Global implant survival was 99% at five years, 97.8% at 10 years and 95.8% at 12 years.

DISCUSSION

The clinical and radiological results of the cruciate-retaining fixed bearing EUROP total knee arthroplasties, with three cases of revision arthroplasty at 12 years of follow-up are satisfactory and comparable to similar implants.

High-flexion total knee replacement: functional outcome at one year

Implants designed for enhanced flexion offer the prospect of improved function after total knee replacement (TKR). Whereas most studies evaluating these implants have focused on the range of knee flexion achieved, this study investigated the quality of function in deep knee flexion. The influences of residual pain and maximum flexion angle on function in deep knee flexion were also examined. Eighty-three patients (100 knees) were prospectively followed for 1 year after TKR with a rotating-platform posterior-stabilized high-flexion prosthesis. Range of motion was measured and Knee Society scores were calculated. A questionnaire evaluated residual knee pain and function in high-flexion activities. Mean Knee Society score was 95, and mean knee flexion was 125°, yet 20% of patients could neither kneel, nor squat, nor sit on their heels. Fifty-seven percent were able to kneel without significant difficulty; 69% were able to squat without significant difficulty; and 46% were able to sit on their heels without significant difficulty. Function in deep flexion correlated with pain scores but did not correlate with knee flexion angles or Knee Society scores. Results 1 year after TKR with a rotating-platform posterior-stabilized high-flexion prosthesis are encouraging, but one in five patients remain significantly limited in high-flexion activities.

Ten-year results of an inset biconvex patella prosthesis in primary knee arthroplasty

The inset biconvex patella component is an alternative form of patella resurfacing in knee arthroplasty. We retrospectively reviewed 433 patients in whom 521 patella prostheses were implanted before April 1997 to determine survivorship, factors associated with failure of the implant, incidence of anterior knee pain, and factors that may be associated with the latter. We had clinical results for 204 surviving patients (242 knees) without failure of their implants with a minimum 10-year followup (mean, 11.4 years; range, 10-17 years). For the remaining 229 patients we used chart or radiographic review to determine if failure of their implant or other complications had occurred. At latest followup, 14 patella components had been revised for aseptic reasons or were radiographically loose. The 10-year Kaplan-Meier survivorship for the entire cohort for aseptic failure was 97.0%. Aseptic failure of the patella component was associated with the presence of osteonecrosis and the absence of a superior rim of bone radiographically. The incidence of anterior knee pain in surviving patients without failure of their implants was 7.8%. No factor examined was associated with anterior knee pain. Survivorship and clinical and radiographic results are equivalent, but not clearly superior, to those reported for other forms of patella resurfacing.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Comparative flexion after rotating-platform vs fixed-bearing total knee arthroplasty

A retrospective review of rotating-platform (n = 113) and fixed-bearing (n = 100) total knee arthroplasties at a minimum 2-year follow-up was performed. All patients in both groups in this study had osteoarthritis and underwent surgery by 1 of the 2 senior authors at 1 of 2 institutions. A cruciate-retaining total knee arthroplasty was implanted with patellar resurfacing in all cases. The only difference between the 2 groups was the design of the tibial bearing and its tibial tray. Through minimization of confounding variables relating to pathology, surgeon, institution, soft-tissue balancing, and type of prosthesis, this study isolates articular design as a variable. We could not demonstrate any significant difference in knee flexion after either fixed-bearing or rotating-platform cruciate-retaining total knee arthroplasty.

Primary total knee arthroplasty using the Genesis I total knee prosthesis: a 5- to 10-year follow-up study

This study analyzed the data from 82 primary total knee arthroplasties performed in 74 patients using the Genesis Total Knee Arthroplasty System. Ten men and 64 women with a mean age of 78 years were evaluated at a mean follow-up of 7 years. Seventy procedures used cemented femoral and tibial components, and 12 used cementless femoral and tibial components. The preoperative mean HSS score was 39. At the most recent follow-up, the mean HSS score increased to 92. The mean preoperative range of motion was 82 degrees and increased to 108 at the most recent follow-up. Clinically, there were 63 excellent (77%), 14 good (17%), 4 fair (5%), and 1 poor (1%) result.

Measuring flexion in knee arthroplasty patients

Flexion following total knee arthroplasty can be visually estimated, measured with a goniometer placed against the patient's leg, or measured from a lateral radiograph of the flexed knee. Three examiners, in a blinded fashion, estimated the degree of maximal knee flexion and measured the flexion with a goniometer for 27 knees in 16 patients. A lateral knee radiograph then was taken and the flexion angle was measured from the radiograph by 2 different methods. Although interobserver and intraobserver correlation coefficients were high (0.79 and 0.92), 45% of the visual estimates and 22% of the goniometer measurements differed by 5 degrees or greater from the radiographic measurements. These differences increased as the flexion angle increased. Body mass index did not affect the accuracy of the estimates or goniometer measurements.

Knee scores change with length of follow-up after total knee arthroplasty

Patients undergoing primary total knee arthroplasty (TKA) between 1989 and 1994 were evaluated preoperatively and postoperatively with the Knee Society scoring system at 3 time intervals: 1 to 2 years, 3 to 6 years, and more than 7 years. Knee prosthesis and functional scores improved statistically after TKA. At last follow-up evaluation, a statistically significant decline was found in functional knee scores that was related to an increase in numbers of patients in category C. Progression of arthritis at other sites, especially lumbar spine and hips, and cardiopulmonary problems were the most common cause of limited functional capacity. Women were found to have lower preoperative and postoperative functional scores. Patient weight, body mass index (BMI), and age at surgery showed no correlation with postoperative functional scores. The inclusion of functional categories would appear to be warranted when reporting long-term results of TKA.