Cruciate-retaining total knee arthroplasty at 5 to 7 years followup

Long-term Results of Partial Release Versus Nonrelease of the Posterior Cruciate Ligament at Cruciate-Retaining Total Knee Arthroplasty: Minimum 15-Year Follow-up

The goal of this study was to compare the clinical and radiologic results of posterior cruciate ligament (PCL) partial release and PCL nonrelease in performing cruciate-retaining total knee arthroplasty (CR-TKA) for a long-term follow-up period of greater than 15 years. A total of 224 patients underwent CR-TKA in our hospital from June 1996 to April 2002 with greater than 15 years of follow-up. We divided the subjects into 2 groups based on release of the PCL. Group 1 was the PCL partial release group (88 cases), and group 2 was the PCL nonrelease group (136 cases). The mean follow-up period was 16.8 years (range, 15.5-19.5 years). We compared the clinical results by measuring the Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score preoperatively and at the last follow-up. For radiologic results, the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System was used and stress radiographs were obtained at the last follow-up to evaluate PCL function. There was no statistically meaningful difference in radiologic and clinical results between the 2 groups. Radiolucent lines were found for 13 patients radiologically (6 in group 1 and 7 in group 2). No instability as a result of PCL insufficiency required revision surgery on stress radiography at the last follow-up. If an appropriate procedure is performed according to PCL function intraoperatively, CR-TKA can produce a satisfactory result on long-term follow-up. [Orthopedics. 2022;45(4):233-238.].

Clinical, Functional, and Midterm Survival Analysis on Sigma Curved Plus Ultracongruent Polyethylene Insert in Primary Total Knee Arthroplasty: A Retrospective Study

BACKGROUND

Posterior-stabilized (PS) total knee arthroplasty (TKA) poses problems such as the need for intercondylar notch bone resection as well as cam and post wear and patella clunk. Owing to its heightened anterior profile, an ultracongruent polyethylene insert prevents the excessive posterior translation of tibia in the case of a deficient or scarified posterior cruciate ligament (PCL). This study aimed to determine whether an ultracongruent insert provides satisfactory clinical and functional outcomes and midterm survival benefits.

METHODS

Based on the reviewed medical records of 200 patients, 240 primary TKA cases involving the use of Sigma Curved Plus (DePuy International, Ltd., Leeds, UK) ultracongruent insert were retrospectively enrolled in this study. Follow-up data were used to evaluate the clinical and radiological outcomes and to conduct a Kaplan-Meier survival analysis.

RESULTS

The mean follow-up duration for 224 knees was 5.8 years (range 5-6.5 years). A revision was made due to infection in two patients and due to periprosthetic fractures in two other patients. The mean knee flexion improved from 101.97° ± 9.43° (range 85°-125°) to 125.75° ± 9.58° (range 100°-140°) at the final follow-up. The mean Knee Society score improved from 43.1 ± 9.76 to 88.3 ± 3.2, and the function score improved from 44.95 ± 7.26 to 90.16 ± 3.71. None of the patients showed radiographic loosening of either insert component, but 22 (5%) patients showed radiolucent lines (<2 mm). The Kaplan-Meier analysis showed that the five-year survival of the insert with an endpoint of revision for any reason was 98.1% (confidence interval, CI, 95.7-99.6%).

CONCLUSION

The Sigma Curved Plus insert showed a low failure rate with good clinical, functional, and midterm survival outcomes in comparison to standard outcomes reported in earlier studies. Further follow-up studies are warranted to determine whether the insert's performance is maintained in the long term.

Clinical and radiological results of cruciate-retaining total knee arthroplasty with the NexGen®-CR system: comparison of patellar resurfacing versus retention with more than 14 years of follow-up

BACKGROUND

The purpose of this study is to analyze clinical and radiological outcomes of patients (with a minimum of 14 years of follow-up) who underwent cruciate-retaining (CR) total knee arthroplasty (TKA) using a NexGen®-CR, comparing a patellar resurfacing group with a patellar retention group.

METHODS

From June 1996 to April 2002, 116 cases of TKA using a NexGen®-CR who had at least 14 years of follow-up were enrolled in this study. Among them, 68 cases had patellar resurfacing and 48 had patellar retention. The average follow-up period was 14.8 years (14.1-18.7). Clinical scores and range of motion (ROM) were evaluated preoperatively and at the last follow-up in all patients. The Hospital for Special Surgery (HSS) score, Knee Society Score (KSS), Western Ontario and MacMaster Universities Osteoarthritis (WOMAC) score, and a new patellar score were assessed. Radiological evaluations are done by analyzing the tibiofemoral angle, loosening, and a radiolucent line on the radiograph by American Knee Society Roentgen Graphic Evaluation.

RESULTS

The average HSS score of both the patellar resurfacing group and retention group increased from 42.3 and 41.2 preoperatively to 90.2 and 90.8 at the last follow-up, respectively. The KSS, WOMAC score, patellar score, and knee joint ROM also improved significantly in both groups. However, there were no significant differences in clinical results between the two groups. On the radiological evaluation, the tibiofemoral angle in both groups had improved from varus 7.8° and 7.2° preoperative to valgus 4.9° and 4.8°, respectively. The average angles of α, β, γ, and δ were 94.1°, 90.4°, 3.2°, and 87.8° in the patellar resurfacing group and 94.4°, 89.8°, 3.3°, and 88.1° in the patellar retention group, respectively. A radiolucent line shown on radiograph was noted in a total of seven cases, three in the patellar resurfacing group and four in the patellar retention group. In the patellar resurfacing group, among the seven zones on the tibia radiograph, all cases were located at the medial side of tibia and two cases were in zone 1 and one case in zone 2, and in the patellar retention group, three cases were in zone 1 and 1 case was in zone 2, also located on the same side.

CONCLUSIONS

We achieved satisfactory clinical and radiological outcomes on long-term follow-up when performing TKAs with a NexGen®-CR. There was no significant difference in clinical or radiological results between the patellar resurfacing and retention groups in our study.

Does cruciate-retaining total knee arthroplasty enhance knee flexion in Western and East Asian patient populations? A meta-analysis

INTRODUCTION

This study analyzed the published data to examine if CR TKAs can enhance the flexion and functional outcomes of the knee in the Western and East Asian populations using a meta-analysis approach.

MATERIALS AND METHODS

A systematic review of literature published through Medline and EMBASE was conducted. The inclusion criteria were: primary TKA, follow up duration greater than one year, a fixed bearing CR prosthesis, and data for maximum pre- and post-operative flexion along with standard deviations or errors. We estimated the weighted mean differences between pre- and post-operative flexion, extension and knee scores (KSS and HSS) via a random effect model.

RESULTS

Seventeen articles were selected and reviewed among 1229 studies that included 1090 knees of the Western and 516 knees of the East Asian. No significant difference was noted in maximal knee flexion pre- and post-operatively, when all the studies were pooled together (-0.17°, p=0.93, post-operative<pre-operative). The mean difference in flexion was -1.87° (p=0.2) and 2.03° (p=0.17), respectively in the both populations. However, the extension angle was significantly improved by -5.49° and -13.05° (p<0.05), respectively. KSS scores were significantly improved by 46.39 and 51.63, and HSS scores by 36.65 and 30.67 (p<0.05), respectively in the both populations.

CONCLUSION

The meta-analysis indicated that contemporary CR TKAs have not been shown to enhance post-operative flexion capability in the Western and East Asian. The extension angles of the knee and the knee scores were significantly improved in both populations.

High-flexion prosthesis improves function of TKA in Asian patients without decreasing early survivorship

BACKGROUND

Two previous studies recently raised the possibility of a high risk of early femoral components loosening with high-flexion (HF) prostheses in Asian populations and suggested that the high failure rate of HF TKAs was associated with HF ability. However, these findings are controversial given other studies reporting a low incidence of aseptic failures in HF prostheses.

QUESTIONS/PURPOSES

We therefore determined (1) the rate of achieving postoperative HF after HF TKA; (2) whether the aseptic loosening rate of HF prostheses is high; and (3) whether the survivorship was worsened in patients who achieved postoperative deep knee flexion in our cohort of Korean patients.

METHODS

We retrospectively reviewed 488 patients who had 698 primary TKAs using the NexGen(®) Legacy Posterior-Stabilized Flex system implanted from 2003 to 2010. There were 40 men and 448 women with a mean age of 68 years. We obtained Hospital for Special Surgery scores, maximal flexion, and radiographs. The minimum followup for functional and radiographic evaluations was 2 years (median, 4.8 years; range, 2-8.7 years). We performed a survival analysis on all patients for aseptic loosening.

RESULTS

Three hundred sixty knees (52%) could achieve ≥ 135° maximum flexion. Six of the 698 knees (0.9%) developed aseptic loosening (three femoral and three tibial). The survival at 5 years for aseptic loosening was 99.1%. The overall survival for aseptic failure did not differ between knees that achieved HF and those that did not.

CONCLUSIONS

We observed a low incidence of early aseptic loosening of HF designs in this series. Our findings suggest HF TKAs have high survival in Asian patients at 5 years although half of the patients attained maximum flexion more than 135° postoperatively.

Results of Total Knee Arthroplasty with NexGen LPS-flex Implant Using Navigation System (Brain Lab): Results with a 5-year Follow-up

Purpose

To evaluate the clinical and radiological results of patients that underwent total knee arthroplasty (TKA) with a NexGen LPS-Flex implant using a Navigation system (Brain Lab).

Materials and Methods

Between January 2001 and December 2005, 55 knees in 46 patients which used the NexGen LPS-Flex implant with a Navigation system (Brain Lab) for primary TKA were clinically and radiologically evaluated after a minimum follow-up of 5 years. Evaluation included preoperative and postoperative range of motion (ROM), Knee Society Score (KSS), tibio-femoral angle and postoperative complications.

Results

Knee ROM was increased from 118.9° preoperatively to 126.9° at the last follow up. In addition, the preoperative flexion contracture improved from 6.5° to 1.8° postoperatively. The mean KSS and functional score were improved from 59.8 and 51.2 to postoperative scores of 86.4 and 85.2 respectively. The rate of appearance of radiolucency in X-ray was 21.8%. One case of superficial skin infection and one case of aseptic loosening were noted as complications but, did not require a revision surgery.

Conclusions

TKA with NexGen LPS-Flex implant using Navigation system (Brain Lab) showed satisfactory improvement in pain and function, but more long term follow up will be needed to complete verification.

Outcomes of the different types of total knee arthroplasty with the identical femoral geometry

Purpose

There are controversies around the role of the posterior cruciate ligament and the effect of design modifications for high flexion in total knee arthroplasty (TKA). So, we compared the clinical outcomes of the cruciate retaining (CR), posterior stabilized (PS), and high flexion posterior stabilized (F-PS) designs in TKA with identical femoral geometry.

Materials and Methods

One hundred seventy nine knees with 3 different types of prostheses after a minimum 5-year follow-up were enrolled in this retrospective study: 45 with CR, 40 with PS and 94 with F-PS. The mean ages of these groups were 65.7, 67.2, and 67.5, and the mean durations of follow-up were 8.1, 8.0, and 6.8 years, respectively. We compared the range of motion, functional outcomes, and radiographic measurements at the 2-year follow-up and last follow-up.

Results

The maximal flexion angle was significantly lower in the CR group than the F-PS group at the 2-year follow-up. However, there was no significant difference at the last follow-up. Functional outcomes and survival rate of the three groups were similar at the last follow-up.

Conclusions

Three different types of TKAs (CR, PS and F-PS) with identical femoral geometry showed similar mid-term outcomes with regard to the range of motion, functional outcomes and survival rate.

Early aseptic loosening with a precoated low-profile tibial component: a case series

Between March 2007 and December 2008, we performed 529 consecutive total knee arthroplasties in 460 patients with the Zimmer (Warsaw, IN) NexGen MIS Tibial Component using a minimally invasive approach. Eight knees in 8 patients (1.5%) were revised for early aseptic loosening of the tibial component despite normal initial postoperative radiographs. Several additional patients have concerning radiographic signs of pending failure. The mean time to revision was 17 months (range, 9-31 months). Intraoperatively, in all cases, more than 50% of the tibial tray was devoid of cement and factory-applied polymethylmethacrylate. Our experience with early aseptic loosening of this tibial component has led us to discontinue its use until the etiology of the high early failure rate is able to be determined.

Knee arthroplasty with a medially conforming ball-and-socket tibiofemoral articulation provides better function

BACKGROUND

A knee design with a ball-and-socket articulation of the medial compartment has a femoral rollback profile similar to the native knee. Compared to a conventional, posterior-stabilized knee design, it provides AP stability throughout the entire ROM. However, it is unclear whether this design difference translates to clinical and functional improvement.

QUESTIONS/PURPOSES

We asked whether the medially conforming ball-and-socket design differences would be associated with (1) improved ROM; and (2) improved American Knee Society, WOMAC, Oxford Knee, SF-36, and Total Knee Function Questionnaire scores compared to a conventional, fixed-bearing posterior-stabilized TKA.

PATIENTS AND METHODS

We enrolled 82 patients in a single-center, single-blinded, randomized, controlled trial comparing the medially conforming ball-and-socket design knee prosthesis to a posterior-stabilized total knee prosthesis. Our primary end point was ROM. Our secondary end points were American Knee Society, WOMAC, Oxford Knee, SF-36, and Total Knee Function Questionnaire scores. All patients were followed at 1 and 2 years.

RESULTS

The mean ROM was 100.1° and 114.9° in the posterior-stabilized and medially conforming ball-and-socket groups, respectively. The physical component scores of SF-36 and Total Knee Function Questionnaire were better in the medially conforming ball-and-socket group. We found no difference in American Knee Society, WOMAC, and Oxford Knee scores.

CONCLUSIONS

Both implant designs similarly relieved pain and improved function. The medially conforming ball-and-socket articulation provided better high-end function as reflected by the Total Knee Function Questionnaire.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Mid-Term Results for Three Contemporary Total Knee Replacement Designs — A Comparative Study of 104 Patients with Primary Osteoarthritis

Aims:

The purpose of this study was to compare retrospectively the mid-term clinical and radiological results of three contemporary knee designs in cohorts operated on in the same hospital during the same time period.

Materials and Methods:

We evaluated mid-term clinical and radiographic outcome of three contemporary total knee designs (the AGC V2, the Duracon and the Nexgen) in 104 consecutive patients (129 knees) operate on for primary knee osteoarthritis at our hospital. The mean indexed age at the time of the operation was 69.2 years (range, 49.3 to 81.1 years). The mean follow-up time was 6.0 years (range, 0.2 to 7.9). All patients were followed for at least three years or until the first revision. In the survival analyses, the end point was defined as, revision for any reason.

Results:

The Kaplan-Meier survival analysis showed a 98% (95% CI 94–100) survival rate for the NexGen, a 98% (95% CI 93–100) for the AGC and a 90% (95% CI 81–99) for the Duracon design at six years. Both the mean KSS for pain, KSS for function and the mean clinical knee score improved significantly in all three groups. There was no difference between the three designs in mid-term survivorship.

Conclusions:

Most of the revisions could be directly linked to perioperative surgical errors. In conclusion, the most recently introduced knee replacements of the present study (Duracon and Nexgen) did not show any clinically significant benefit over the older design (AGC) in the mid-term.

Osteolysis in well-functioning fixed- and mobile-bearing TKAs in younger patients

BACKGROUND

Periprosthetic osteolysis is an increasingly prevalent complication of TKA. To reduce the polyethylene wear and periprosthetic osteolysis, particularly in young patients, the design of the contemporary fixed-bearing TKAs has been modified and mobile-bearing TKAs have been introduced.

QUESTIONS/PURPOSES

We asked whether the prevalence of osteolysis would be less in well-functioning mobile-bearing TKAs than in well-functioning contemporary fixed-bearing TKAs in young patients.

PATIENTS AND METHODS

We compared 488 patients (894 knees) who received fixed-bearing knee prostheses with 445 patients (816 knees) who received mobile-bearing knee prostheses. There were 187 men and 301 women (mean age, 58.6 years; range, 33-65 years) in the fixed-bearing group and 167 men and 278 women (mean age, 55.7 years; range, 33-65 years) in the mobile-bearing group. The mean followup was 12.6 years (range, 10-17 years) in the fixed-bearing group and 12.9 years (range, 10-17 years) in the mobile-bearing group.

RESULTS

The incidence of osteolysis was 1.6% (14 of 894 knees) in the fixed-bearing group and 2.2% (18 of 816 knees) in the mobile-bearing group at the final review. The mean postoperative Knee Society knee and function scores were 92.9 points and 83.5 points, respectively, in the fixed-bearing group and 90.7 points and 83.8 points, respectively, in the mobile-bearing group. The revision rates were 3.7% (33 of 894 knees) in the fixed-bearing group and 2.7% (22 of 816 knees) in the mobile-bearing group.

CONCLUSIONS

We found the incidence of osteolysis, rate of revision, and implant survivorship were similar between fixed-bearing and mobile-bearing TKAs in younger patients.

In vivo flexion and kinematics of the knee after TKA: comparison of a conventional and a high flexion cruciate-retaining TKA design

This study investigated the in vivo 6DOF knee kinematics and tibiofemoral contact location after total knee arthroplasty using a conventional and a high flexion cruciate retaining component (15 NexGen CR, 11 NexGen CR-Flex). Each patient performed a single-leg lunge while being imaged by a dual fluoroscopic imaging system. Data were analyzed at hyperextension, 0 degrees to 90 degrees in 15 degrees intervals, and at maximum flexion. The average maximum weight-bearing flexion for all the CR patients was 110.1 degrees +/- 13.4 degrees , and for all the CR-Flex patients was 108.2 degrees +/- 13.2 degrees . No difference was seen in the maximum flexion achieved by the patients, and the kinematics demonstrated by the groups was similar. However, at high flexion, the tibiofemoral articulating surfaces were more conforming in the CR-Flex design than the CR design, suggesting that the use of the high flexion component improved the tibiofemoral contact environment at high flexion in patients who could achieve high flexion.

Midterm survival of a contemporary modular total knee replacement

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1).

The PFC Sigma knee system appears to provide excellent results in the medium term.

Midterm results with the PFC Sigma total knee arthroplasty system

We prospectively studied 207 consecutive patients (284 knees) undergoing total knee arthroplasty (June 1996 to December 1997) with a cemented tricompartmental Sigma PFC (DePuy Orthopaedics, Warsaw, Ind) total knee arthroplasty via a standard procedure (median follow-up, 87 months). Cruciate-retaining (272 knees, 96%) and cruciate-substituting (12, 4%) implants were used. There was one revision secondary to a ligament disruption after a fall. No implants were radiographically loose or at risk for loosening. Radiolucencies (none>2 mm or progressive) were shown on anteroposterior (7% of medial tibias) and lateral (17% of posterior femora) radiographs. Knee Society pain scores improved significantly (preoperative median, 20 points; postoperative median, 50 points [P<.001]). The PFC Sigma Knee system has excellent midterm durability.

Tibial component fixation in total knee arthroplasty: a comparison of pegged and stemmed designs

This study compares midterm radiographic, functional, and quality-of-life outcomes in patients receiving a cemented tibial component that has either a short intramedullary stem or one that has a pegged tibial component. A cohort of 181 patients received 225 NexGen cruciate-retaining implants (84 stemmed, 141 pegged) during total knee arthroplasty, with annual follow-up examinations for up to 7 years. Both types of tibial components were associated with excellent radiographic and clinical results with no radiographic evidence of implant loosening or osteolysis. Clinical outcomes included improvement in joint function and patient function, as well as quality of life. Survival analysis showed 98% survival at 7 years with both implants. Pegged tibial components offered comparable midterm radiographic, functional, and quality-of-life results to stemmed components.

Factors affecting the impingement angle of fixed- and mobile-bearing total knee replacements: a laboratory study

Maximum flexion-or impingement angle-is defined as the angle of flexion when the posterior femoral cortex impacts the posterior edge of the tibial insert. We examined the effects of femoral component placement on the femur, the slope angle of the tibial component, the location of the femoral-tibial contact point, and the amount of internal or external rotation. Posterior and proximal femoral placement, a more posterior femoral-tibial contact point, and a more tibial slope all increased maximum flexion, whereas rotation reduced it. A mobile-bearing knee gave results similar to those of the fixed-bearing knee, but there was no loss of flexion in internal or external rotation if the mobile bearing moved with the femur. In the absence of negative factors, a flexion angle of 150 degrees can be reached before impingement.

Custom total knee replacement in a dog with femoral condylar bone loss

OBJECTIVE

To report surgical planning, technique, and outcome of custom total knee replacement (TKR) performed to manage a medial femoral condylar nonunion in a dog.

STUDY DESIGN

Clinical case report.

ANIMAL

A 3-year-old, 20 kg Karelian Bear Hound.

METHODS

Computed tomographic scan of the left pelvic limb was used to build a stereolithography model of the distal portion of the femur. The model was used to create a custom augment to replace the missing medial femoral condyle and a custom stem for intramedullary condylar cemented fixation. The augment and stem were adapted to femoral and tibial components already available. The model was used to rehearse the surgery and then the custom prosthesis was implanted.

RESULTS

Weight bearing returned 8 hours after surgery and improved thereafter. Joint alignment was normal and prosthetic joint motion was 60-165 degrees postoperatively. The dog resumed moose hunting 3 months after surgery. Peak vertical force and impulse of the operated limb measured 17 months after surgery were 65% and 47% of the normal, contralateral limb.

CONCLUSION

Based on short-term follow-up, cemented canine TKR was successfully achieved for management of a severely abnormal stifle joint.

CLINICAL RELEVANCE

With further refinement and development of commercially available prostheses, TKR should be possible for canine patients.