Functional outcomes comparing Triathlon versus Duracon total knee arthroplasty: does the Triathlon outperform its predecessor?

The Impact of Total Knee Replacement with a Customized Cruciate-Retaining Implant Design on Patient-Reported and Functional Outcomes

Purpose: To treat patients with tricompartimental knee osteoarthritis (OA), a customized cruciate-retaining total knee arthroplasty (CCR-TKA) system can be used, including both individualized instrumentation and implants. The objective of this monocentric cohort study was to analyze patient-reported and functional outcomes in a series of patients implanted with the second generation of this customized implant. Methods: At our arthroplasty center, we prospectively recruited a cohort of patients with tricompartmental gonarthrosis to be treated with total knee replacement (TKA) using a customized cruciate-retaining (CCR) implant design. Inclusion criteria for patients comprised the presence of intact posterior cruciate and collateral ligaments and a knee deformity that was restricted to <15° varus, valgus, or flexion contracture. Patients were assessed for their range of motion (ROM), Knee Society Score (KSS), Western Ontario and McMaster University osteoarthritis index (WOMAC), and short form (SF)-12 physical and mental scores, preoperatively, at 3 and 6 months, as well as at 1, 2, 3, and 5 years of follow-up (FU) postoperatively. Results: The average age of the patient population was 64 years (range: 40–81), the average BMI was 31 (range: 23–42), and in total, 28 female and 45 male patients were included. Implant survivorship was 97.5% (one septic loosening) at an average follow-up of 2.5 years. The KSS knee and function scores improved significantly (p < 0.001) from, respectively, 41 and 53 at the pre-operative visit, to 92 and 86, respectively, at the 5-year post-operative time point. The SF-12 Physical and Mental scores significantly (p < 0.001) improved from the pre-operative values of 28 and 50, to 50 and 53 at the 5-year FU, respectively. Patients experienced significant improvements in their overall knee range of motion, from 106° at the preoperative visit to 122°, on average, 5 years postoperatively. The total WOMAC score significantly (p < 0.001) improved from 49.1 preoperatively to 11.4 postoperatively at 5-year FU. Conclusions: Although there was no comparison to other implants within this study, patients reported high overall satisfaction and improvement in functional outcomes within the first year from surgery, which continued over the following years. These mid-term results are excellent compared with those reported in the current literature. Comparative long-term studies with this device are needed. Level of evidence 3b (individual case–control study).

Comparison between Mid-Term Results of Total Knee Arthroplasty with Single-Radius versus Multiple-Radii Posterior-Stabilized Prostheses

Single-radius (SR) prostheses and multiple-radii (MR) prostheses have different theoretical advantages; however, few comparative studies have been reported. The aim of the study was to compare mid-term clinical, radiological, and survival outcomes of SR and MR posterior-stabilized prostheses in total knee arthroplasty (TKA). Two hundred consecutive patients who underwent TKA between January 2012 and July 2013 were enrolled in the SR group (100 patients) and an MR group (100 patients), with a minimum follow-up of 5 years. Functional, radiological, satisfaction, and survival rates were evaluated. There was a significantly higher range of motion (ROM) in the SR group than in the MR group (flexion, 123.65 ± 10.12 degrees vs. 115.52 ± 10.03 degrees, p < 0.001). Quadriceps strength (3.05 ± 0.43 vs. 2.68 ± 0.58 kg, p = 0.025) and chair test results (80 [93.02%] vs. 69 [83.13%], p = 0.027) were better in the SR group than in the MR group. The SR group also had significantly less anterior knee pain (6 [6.98%] vs. 15 [18.07%], p < 0.05) and a better satisfaction rate than those in the MR group. No significant differences were observed in clinical scale scores such as Hospital for Special Surgery (HSS), Knee Society Score (KSS), and Short-Form 12 (SF-12), radiological results in terms of component position and radiolucent lines. The Kaplan-Meier survival curve estimates at 5 years were not significantly different (96.91% [95% confidence interval [CI]: 93.5-99.5%] vs. 94.86% [95% CI: 90.6-98.6%], p = 0.4696). The SR prosthesis design was better than that of the MR in terms of ROM, reduced anterior knee pain, contributions to better recovery of the extension mechanism, and higher satisfaction rates. The SR had similar results in clinical scales such as HSS, KSS, SF-12, radiological, or survival results to MR prostheses. More accurate measurements and longer-term follow-up are required.

Clinical Course of Pain and Function Following Total Knee Arthroplasty: A Systematic Review and Meta-Regression

BACKGROUND

Total knee arthroplasty (TKA) is widely considered a successful intervention for osteoarthritis and other degenerative knee diseases. This study addresses the need for a high-quality meta-analysis that outlines the clinical course of pain and function post-TKA.

METHODS

The review included prospective cohort studies assessing pain or function of patients undergoing primary TKA at baseline (preoperatively) and at least 2 additional time points including one at least 12 months postoperatively. Two reviewers independently screened references, extracted data, and assessed risk of bias using the Quality in Prognosis Studies tool. The time course of recovery of pain and function was modeled using fractional polynomial meta-regression.

RESULTS

In total, 191 studies with 59,667 patients were included, most with low risk of bias. The variance-weighted mean pain score (/100, 0 = no pain) was 64.0 (95% confidence interval [CI] 60.2-67.7) preoperatively, 24.1 (95% CI 20.3-27.9) at 3 months, 20.4 (95% CI 16.7-24.0) at 6 months, and 16.9 (95%CI 13.6-20.3) at 12 months, and remained low (10.1; 95% CI 4.8-15.4) at 10 years postoperatively. The variance-weighted mean function score (/100, 0 = worst function) was 47.1 (95% CI 45.7-48.4) preoperatively, 72.8 (95% CI 71.3-74.4) at 3 months, 76.3 (95% CI 74.7-77.8) at 6 months, and 78.1 (95%CI 76.4-79.7) at 12 months. Function scores were good (79.7; 95% CI 77.9-81.5) at 10 years postoperatively.

CONCLUSION

Patients undergoing primary TKA can expect a large and rapid but incomplete recovery of pain and function in the first postoperative year. At 10 years, the gains in pain scores may still remain while there is an improvement in function.

Patient-specific cruciate-retaining total knee replacement with individualized implants and instruments (iTotal™ CR G2)

OBJECTIVE

Treatment of tricompartimental osteoarthritis (OA) using customized instruments and implants for cruciate-retaining total knee arthroplasty. Use of patient-specific instruments and implants (ConforMIS iTotal^TM CR G2) together with a 3D-planning protocol (iView®). Retropatellar resurfacing is optional.

INDICATIONS

Symptomatic tricompartmental OA of the knee (Kellgren-Lawrence stage IV) with preserved posterior cruciate ligament (PCL) after unsuccessful conservative or joint-preserving surgical treatment.

CONTRAINDICATIONS

Knee ligament instabilities of the posterior cruciate or collateral ligaments. Infection. Relative contraindication: knee deformities >15° (varus, valgus, flexion); prior partial knee replacement.

SURGICAL TECHNIQUE

Midline or parapatellar medial skin incision, medial arthrotomy; distal femoral resection with patient-specific cutting block; tibial resection using either a cutting jig for the anatomic slope or a fixed 5° slope. Balancing the knee in extension and flexion gap using patient-specific spacer. The final tibial preparation achieved with gap-balanced placement of the femoral cutting jigs. Kinematic testing using anatomic trial components. Final implant components are cemented in extension. Wound layers are sutured. Drainage is optional.

POSTOPERATIVE MANAGEMENT

Sterile wound dressing; compressive bandage. No limitation of the active and passive range of motion. Optional partial weight bearing during the first 2 weeks, then transition to full weight bearing. Follow-up directly after surgery, at 12 and 52 weeks, then every 1-2 years.

RESULTS

Overall 60 patients with tricompartmental knee OA and preserved PCL were treated. Mean age was 66 (range 45-76) years. Minimum follow-up was 12 months. There was 1 septic revision after a low-grade infection, 1 reoperation to replace the patellar due to patellar osteoarthritis and 3 manipulations under anesthesia (MUAs) to increase range of motion. Radiographic analyses demonstrated an ideal implant fit with less than 2 mm subsidence or overhang. The WOMAC score improved from 154.8 points preoperatively to 83.5 points at 1 year and 59.3 points at 2 years postoperatively. The EuroQol-5D Score also improved from 11.1 points preoperatively to 7.7 points at 1 year postoperatively.

Better quadriceps and hamstring strength is achieved after Total knee Arthroplasty with single radius femoral prostheses: a retrospective study based on isokinetic and isometric data

Background

Strength deficits, muscle imbalances, and quadriceps inhibition are common after the total knee arthroplasty (TKA). It was suggested that theoretically single radius (SR) femoral protheses could provide longer extensor moment arm compared to the multiple radius (MR) design. However, quantitative evidence has not yet been reported. Thus, the aim of the study was to investigate the differences in isokinetic data and to compare the patient-reported outcome scores between TKA SR and MR design.

Method

The present retrospective study included 36 TKA involving 16 knees (9 patients) using SR design implant and 20 knees (11 patients) using MR design implant. The mean follow-up time was longer than 1 year. Isokinetic knee flexion and extension torques of the operated leg were evaluated at 60°/s and 180°/s. Quadriceps and hamstring torques and ratios, work and power were recorded. Angle-specific torques were also collected at different extension or flexion angles.

Results

Both groups showed improvement in knee society scores (KSS) and knee injury, and osteoarthritis outcome score (KOOS) after operation. Patients in SR group had significantly higher scores in KSS-knee, symptoms and activities of daily living KOOS sub-score than those in the MR group at the end of the follow-up. The peak knee flexion torque, peak knee extension torque and maximum knee flexion work were greater in SR group at 180°/s and 60°/s. At 60°/s, and SR group had higher average knee flexion power and average knee extension power than MR group. In the isometric contraction test, the knee extension torque was higher in SR group than in MR group. At 180°/s, SR group showed higher flexion torques at 30°, 40°, 50°, 60° compared with MR group. At 60°/s, SR group showed higher flexion torques at 30°, 40°, 50°, 60°, 80° when compared with MR group. Additionally, SR group also provided higher extension torques at 40°, 50°, 60° than the MR group. There were no differences in other isokinetic and isometric parameters between the two groups.

Conclusion

Femoral design exerted an influence on quadriceps and hamstring strength after TKA, and SR design shows advantages, in terms of higher extension and flexion strength, over MR design.

Comparison of functional outcomes between single-radius and multi-radius femoral components in primary total knee arthroplasty: a meta-analysis of randomized controlled trials

PURPOSE

Our purpose in the current meta-analysis was to compare the functional outcomes in patients who have received single-radius (SR) or multi-radius (MR) femoral components in randomized controlled trials (RCTs) for primary total knee arthroplasty (TKA). The hypothesis was that there would be no statistically significant difference between two groups in terms of functional outcomes.

MATERIALS AND METHODS

We searched the international electronic databases PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to February 2020 for RCTs that compared functional outcomes of SR and MR femoral component designs after primary TKA. We performed a meta-analysis of nine RCTs using the Knee Society Score for the knee (KSS-knee), KSS-function, Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), degree of knee flexion, extension, and complications, including postoperative infection and revision surgery.

RESULTS

The meta-analysis revealed no statistically significant differences in all the analyzed variables, including KSS-knee, KSS-function, KOOS, OKS, knee flexion, and knee extension. For postoperative complications, no statistically significant differences were detected for femoral component designs in postoperative infection or incidence of revision surgery between the two groups.

CONCLUSIONS

The current meta-analysis of RCTs did not show any statistically significant differences between SR and MR femoral component designs in terms of postoperative functional outcomes. Evaluated outcomes included functional outcome scores, degree of knee flexion, extension, and complications. However, because of the limited clinical evidence of this study owing to the heterogeneity between the included RCTs, a careful approach should be made in order not to arrive at definite conclusions.

Does Knee Prosthesis Survivorship Improve When Implant Designs Change? Findings from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

TKA generally has excellent long-term survivorship. When a new knee system supersedes a previous model, increased survivorship, improved functional performance, or both may be expected, because key areas of design modification are often targeted to address wear, stability, and the patellofemoral articulation. However, not all design changes are beneficial, and to our knowledge, knee arthroplasty has not been systematically evaluated in the context of design changes that occur during the development of new knee arthroplasty systems.

QUESTIONS/PURPOSES

Using the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) we performed multiple old-to-new comparisons of frequently used contemporary knee implants to ask: (1) does overall prosthesis survivorship free from revision increase when a new knee prosthesis system is introduced to replace a prior prosthesis system? (2) Has survivorship free from revision improved for the revision indications of wear, instability, and patellofemoral articulation issues, where development efforts have been concentrated?

METHODS

Data from the AOANJRR from September 1999 to December 2017 were used to compare the survivorship of prostheses free from revision at a maximum of 17 years in procedures where a new design model was introduced to replace a prior knee system from the same manufacturer. Only prosthesis systems used in a minimum of 2000 primary TKA procedures for osteoarthritis that had a minimum of 5 years of follow-up were included. Varus-valgus constrained and hinge TKA designs were excluded. Cruciate-retaining, posterior-stabilized, and medial pivot-design knees were considered separately. The new and old prosthesis systems were paired for analysis. Survivorship was calculated with Kaplan Meier estimates and comparisons were performed using the Cox proportional hazards method. Subanalyses according to the three main revision indications were performed, and where possible, analyses were performed based on polyethylene types (highly cross-linked polyethylene and ultra-high-molecular-weight polyethylene), combined and separated. Revision was defined as a reoperation of a previous knee arthroplasty in which one or more of the components was removed, replaced, or added. There were 323,955 TKA procedures and 11 new prosthesis system designs that were introduced to replace an earlier knee system from the same manufacturer. Of these prosthesis system pairs, six were cruciate-retaining prostheses, four were posterior-stabilized designs, and one was a medial pivot design.

RESULTS

Six of the 11 knee system pairs showed improved survivorship with the new design, three were no different, and in two, the newer prosthesis systems had a higher rate of revision than the old one did. When revision for wear was analyzed, five prosthesis systems showed improvement, five were no different, and one had a higher rate of revision than the previous system did. There was no improvement in the rate of revision for instability; seven new prosthesis systems showed no difference from the previous system and four new prosthesis systems had a higher rate of revision than the previous system did. A subanalysis of revision for patellofemoral complications showed improvement in two comparisons, no difference in six, and a higher revision rate in two; one could not be calculated because of an insufficient number of revisions for this reason.

CONCLUSIONS

It is difficult to predict whether a new system will demonstrate better survival than a previous one, and widespread uptake of a new design before a benefit is shown in robust clinical studies is unwise. Similarly, adoption of a new system for which there is no difference in survivorship from a previous model may be premature because a new device may have associated unknown and unintended consequences. Healthcare policy makers and therapeutic device regulators should similarly be guided by results and seek out peer-reviewed evidence before accepting change to established practice. Surgeons must be aware that implant changes may not translate into better survivorship and must seek compelling evidence of improvement in survival and/or function before changing systems.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Long-term results of total knee arthroplasty with single-radius versus multi-radius posterior-stabilized prostheses

Background

Single-radius (SR) prostheses and multi-radius (MR) prostheses have different theoretical advantages; however, there has been a paucity of evaluations comparing the two. This study was designed to compare the 10-year clinical, radiological, and survival outcomes of SR and MR posterior-stabilized prostheses in total knee arthroplasty (TKA).

Methods

In this retrospective cohort study, 220 consecutive patients undergoing TKA between October 2006 and October 2007 were divided into the SR group (106 patients, Stryker Scorpio NRG) and the MR group (114 patients, DePuy Sigma PFC), with a minimum follow-up of 10 years. Clinical, functional, and radiological outcomes, as well as satisfaction rates and survival results, were evaluated.

Results

Hospital for Special Surgery and Short Form-12 health survey scores were all significantly improved in both groups at the final follow-up (P < 0.05), but the groups did not differ. The SR group had significantly less anterior knee pain (AKP) and painless crepitation (P < 0.05). Radiological results in terms of radiolucent lines and component position angle showed no differences between groups. The Kaplan-Meier survival curve estimates at 10 years were not significantly different between the groups (P = 0.4172).

Conclusion

Both SR and MR posterior-stabilized prostheses can lead to satisfactory outcomes. The SR prosthesis design gave less anterior knee pain than did the MR prostheses. Two prostheses showed no differences in terms of clinical scales, radiological results, satisfaction rates, and survival results at a long-term follow-up. More accurate measurements are required.

Excellent 10-year patient-reported outcomes and survival in a single-radius, cruciate-retaining total knee arthroplasty

PURPOSE

Over 2 million Triathlon single-radius total knee arthroplasties (TKAs) have been implanted worldwide. This study reports the 10-year survival and patient-reported outcome of the Triathlon TKA in a single independent centre.

METHODS

From 2006 to 2007, 462 consecutive cruciate-retaining Triathlon TKAs were implanted in 426 patients (median age 69 (21-89), 289 (62.5%) female). Patellae were not routinely resurfaced. Patient-reported outcome measures (SF-12, Oxford Knee Scores (OKS), satisfaction) were assessed preoperatively and at 1, 5 and 10 years when radiographs were reviewed. Forgotten Joint Scores (FJS) were collected at 10 years. Kaplan-Meier survival analysis was performed.

RESULTS

At 10-11.6 years, 123 patients (128 TKAs) had died and 8 TKAs were lost to follow-up. There were four aseptic failures (two cases of tibial loosening, two cases of instability) and four septic failures requiring revision. Symptomatic aseptic radiographic loosening was present in three further cases at 11 years. Four (1%) patellae were secondarily resurfaced. OKS score improved by 17.7 ± 9.7 points at 1 year (p < 0.001), and was maintained at 34.7 ± 9.6 at 10 years with FJS 48.5 ± 31.4. Patient satisfaction was 88% at each timepoint. Ten-year survival was 97.9% (95% confidence interval 96.5-99.3) for revision for any reason, 98.9% (97.7-100) for mechanical failure, and 98.6% (97.4-99.8) for aseptic loosening (symptomatic radiographic or revised).

CONCLUSION

The Triathlon TKA continues to show excellent longer-term results with high implant survivorship, low rates of aseptic failure, consistently maintained PROMs and excellent patient satisfaction rates of 88% at 10 years.

LEVEL OF EVIDENCE

II, Prospective cohort study.

Prospective Randomized Comparison of Posterior-Stabilized Versus Condylar-Stabilized Total Knee Arthroplasty: Final Report of a Five-Year Study

BACKGROUND

This report presents the minimum 5-year results of a prospective, randomized, Level of Evidence I study that evaluated cruciate-sacrificing total knee arthroplasty using either a posterior-stabilized (PS) device or a condylar-stabilized (CS) device. We hypothesized that the clinical outcomes of both groups would be equivalent and that there would be differences in operative time and/or blood loss parameters.

METHODS

One-hundred eleven patients undergoing total knee arthroplasty were randomized to receive either a post-cam style tibial insert (PS, n = 56) or a more congruent anterior-lipped tibial insert (CS, n = 55). All posterior cruciate ligaments were sacrificed.

RESULTS

Comparison of the clinical scores and radiographic results between both groups were essentially equivalent with no statistically significant differences at the final 5-year evaluation, although the CS knee group had significantly fewer incidences of postoperative mechanical sensations (P = .01).

CONCLUSION

These results demonstrate that the CS knee provides excellent clinical, functional, and radiographic outcomes that are comparable to the results achieved with the PS knee, with a lower incidence of mechanical sensations, and support the use of a CS device as an alternative to the PS device.

Sagittal flexion arc evaluation for a modern generation single-radius femoral component design

Single-radius femoral total knee design aims to deliver improved kinematic behaviour when compared to the standard two-radii geometry. This study has evaluated the behaviour, through a functional range of motion in the sagittal plane, of a single-radius femoral component compared to a dual-radius standard knee construct. Particular focus was placed on how the flexion axes of the native and replaced knee approximated to the transepicondylar axis through a loaded navigated knee design. Significant differences in flexion arcs were noted between the native and total knee arthroplasty state. These arcs were not uniform in all knees and did not display single-radius behaviour. There were no significant differences in the location of flexion axes in the native and total knee arthroplasty knee. Both exhibited similar posterior and inferior transverse axes of motion with respect to the anatomical epicondylar axis. This work has cast doubt on the reliability under loaded conditions of the single-radius concept, but the close proximity of the flexion axes of each replaced knee in relation to the functional flexion axis of the native knee may be the true basis of this purported improved kinematic performance.

Better functional outcome after single-radius TKA compared with multi-radius TKA

PURPOSE

To determine whether the design of the femoral component influenced patient outcomes.

METHODS

Two hundred and thirty-seven patients were randomized to compare functional outcomes between single-radius TKA (SR, 118 patients) and multi-radius TKA (MR, 119 patients) with a minimum follow-up of 5 years. Prospective pre- and postoperative assessments were performed by the clinical and radiological criteria of the Knee Society Score (KSS), WOMAC and Short-Form 12 (SF12) questionnaires. The extension mechanism was assessed based on the quadriceps strength and chair test. Patient satisfaction was also assessed.

RESULTS

The median follow-up was 5.7 (range 5-7) years. At last follow-up, significant better KSSs (p = 0.001), range of motion (p = 0.001), extension lag (p = 0.020), quadriceps strength (p = 0.004), chair test (p = 0.032) and WOMAC pain (p = 0.002) were found in the SR group. Moreover, the improvements of these variables were early in the SR group (from 6 postoperative months). There were no significant differences in WOMAC function or SF12 physical and mental components. The revision rate and implant survival were similar in both groups. Satisfaction rate was significantly higher in SR group (p = 0.032).

CONCLUSION

This study shows better results with SR cruciate-retaining femoral component than MR component. The use of SR system is recommended because, although the clinically relevant differences were moderate, the functional improvement was earlier and the patient satisfaction higher with this design.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Performance Comparison of Single-Radius Versus Multiple-Curve Femoral Component in Total Knee Arthroplasty: A Prospective, Randomized Study Using the Lower Quarter Y-Balance Test

Midflexion stability after total knee arthroplasty (TKA) is dependent, in part, on implant design. Midflexion performance of a single-radius (SR) design and a multi-radius, or J-curve (JC), design were compared using the Lower Quarter Y-Balance Test (YBT-LQ). Patient-reported outcomes and measures of physical performance were also compared. The authors hypothesized that the SR design would provide superior midflexion stability and, therefore, a greater reach distance in the YBT-LQ when compared with the JC design. Patients undergoing primary, unilateral TKA were prospectively enrolled and block randomized to receive either the SR (n=30) or the JC (n=30) implant. Patients reported outcome measures (Knee Injury and Osteoarthritis Outcome Score, Knee Society Score, and University of California at Los Angeles Activity Score), performed the YBT-LQ, and completed physical performance measures (walking speed, timed up-and-go test, and sit-to-stand test) before surgery and 1 year postoperatively. One year postoperatively, 40 patients (20 SR, 20 JC) were available for analysis. There were no significant differences between the groups regarding age, sex, body mass index, American Society of Anesthesiologists score, YBT-LQ results, or any other variable of interest. In both groups, significant improvements were observed for all variables of interest when compared from preoperatively to 1 year postoperatively. Implant type did not affect patient-reported or physical performance outcomes following TKA; however, patients showed significant improvement in most outcome measures by 1 year postoperatively. The significant limitations in strength and balance in this cohort of patients likely outweigh any subtle differences in implant design. [Orthopedics. 2017; 40(6):e1074-e1080.].

Perioperative and Early Postoperative Comparison of a Modern Cemented and Cementless Total Knee Arthroplasty of the Same Design

BACKGROUND

Cementless total knee arthroplasty (TKA) designs that incorporate a highly porous, titanium surface have the potential to achieve biologic fixation and improve component survivorship. This study's purpose was to compare perioperative and early postoperative outcomes of a cemented vs cementless TKA of the same design.

METHODS

This was a retrospective review of a consecutive series of TKAs performed at a single institution using a cemented or cementless TKA of the same design (Triathlon, Stryker Inc, Mahwah, NJ). All patients with a minimum of 1-year clinical and radiographic follow-up were reviewed, with 1:1 matching performed for age, gender, body mass index, and preoperative Oxford Knee Score. Chi-square or independent student t tests were used for statistical analyses.

RESULTS

Overall, 62 cemented and 66 cementless TKAs were reviewed, with secondary analyses performed after 1:1 matching of 38 patients in each cohort. In both overall and secondary 1:1 matching analyses, there was no difference in baseline demographics (P = .6-.9). Total operative times were decreased in the cementless cohort (P = .03), but there was no difference in the estimated blood loss or change in hemoglobin levels (P = .2-.7). At a mean of 1.4 ± .5 years postoperatively, patients in both cohorts demonstrated similar improvements in Oxford Knee Scores and satisfaction scores (P = .2-.8), with no patients requiring a revision surgical procedure.

CONCLUSION

A recently introduced cementless TKA design demonstrates excellent perioperative and early postoperative results without failures. Continued surveillance is necessary to elucidate the survivorship and potential long-term benefits of this cementless design.

No differences in functional results and quality of life after single-radius or multiradius TKA

PURPOSE

The main objective of this study was to compare the functional results and the impact on quality of life after a single-radius or a multiradius TKA implantation. The secondary objectives were to compare range of motion, satisfaction and the ability to perform daily life activities with both types of implant. It was hypothesized that the single-radius TKA would lead to better functional results and better quality of life than the multiradius TKA.

METHODS

This is a prospective non-randomized study that included 250 cases of a single-radius TKA and 224 of a multiradius posterior-stabilized TKA implanted with the same surgical and rehabilitation protocol.

RESULTS

In the 1- and 5-year follow-up, we found similar knee KSS scores (89.7 ± 12.1 in the multiradius group and 90.3 ± 11.7 in the single-radius group) and functional KSS scores (78.6 ± 21.4 in the multiradius group and 75.8 ± 20.9 in the single-radius group). The pain and the Physical SF-36 scores were also similar. Range of motion (112° ± 12° in the multiradius group and 112 ± 12° in the single-radius group), patients' satisfaction and the ability to perform daily life activities were also similar in both groups.

CONCLUSION

The use of a single-radius or a multiradius posterior-stabilized knee prosthesis can improve the function of the knee and the patients' quality of life in a similar way at the short-term and midterm follow-up. Moreover, range of motion, patient satisfaction and the ability to perform daily life activities are similar with both types of prosthesis. As both types of prosthesis can improve the function and quality of life of the patients in a similar way, the sagittal radius of the femoral component should not be considered the main factor when choosing the model of TKA.

LEVEL OF EVIDENCE

Therapeutic study: Prospective comparative study, Level II.

Meta-Analysis of Outcomes of a Single-Radius Versus Multi-Radius Femoral Design in Total Knee Arthroplasty

BACKGROUND

Although the single-radius (SR) femoral design is known to have theoretical advantages in many aspects, studies of clinical outcomes that compare the SR with the multiple-radius (MR) femoral design are controversial. We performed a meta-analysis to address the hypothesis that a SR femoral design in primary total knee arthroplasty improves patient outcomes.

METHODS

The meta-analysis identified 15 articles reporting the clinical outcomes of 2212 knee replacements using the SR (n = 948) compared with the multiradius (MR; n = 1361) femoral design. Comparing SR with MR, we examined the Knee Society Score for the knee (KSS-knee), KSS-function, knee flexion, range of motion, complications, isometric peak torque of knee, and survival rate.

RESULTS

The range of motion of SR knees was lower than that of MR knees. No differences were found in the analyses of KSS-knee, KSS-function, knee flexion, complications, isometric peak torque of the knee, and survival rate.

CONCLUSION

Our meta-analysis does not provide clinical support for the previously reported theoretical advantages of the SR implant design.

Is Single-Radius Design Better for Quadriceps Recovery in Total Knee Arthroplasty?

Purpose

Although single-radius (SR) designs have a theoretical advantage in quadriceps recovery following total knee arthroplasty (TKA), there has been a paucity of objective evaluation studies.

Materials and Methods

One hundred and twenty minimally invasive TKAs were prospectively randomized by a single surgeon into 2 groups: SR design TKA group and multi-radius design TKA group. Quadriceps force and power were assessed using a dynamometer, and clinical data were investigated preoperatively and 6 weeks, 3 months, 6 months and 1 year postoperatively.

Results

There were no differences between two groups in quadriceps recovery and clinical results throughout the follow-up period. Furthermore, the proportion of patients whose postoperative quadriceps force and power reached preoperative level was similar in both groups.

Conclusions

Femoral component design itself would not significantly influence quadriceps recovery after TKA.

Long-Term Survivorship and Clinical Outcomes Following Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most successful commonly performed orthopedic procedures; as such, the purpose was to assess the long-term outcomes and survivorship of primary TKAs with a dual-radius prosthesis. We evaluated 125-patients (145-knees), with a mean age of 63 years (37-90 years) for a mean 11-year follow-up (10-13 years). Outcomes were assessed with KSS, UCLA, SF-36, satisfaction scores, and aseptic survivorship analysis. At 10-year follow-up, the UCLA (6-points), KSS objective (84-points) and functional (73-points), SF-36 physical (41-points) and mental (51-points), and patient satisfaction (14-points) scores were reported to be good to excellent. The 10-year Kaplan-Meier survivorship rate was 99%; one TKA demonstrated radiographic loosening. At a minimum 10-year follow-up, this device demonstrated satisfactory outcomes and outstanding aseptic-survivorship rates.