High-flex Knee Research Articles

IN FEMALE PRIMARY OSTEOARTHRITIC PATIENTS, UNDERGOING TOTAL KNEE ARTHROPLASTY, IS GENDER-SPECIFIC CRUCIATE RETAINING HIGH-FLEXION KNEE, SUPERIOR TO STANDARD CRUCIATE RETAINING FLEXION KNEE, FROM THE VIEW OF CLINICO-FUNCTIONAL OUTCOMES.

Anthropometric measurements of the human knee, have differences in the women's and the men's knee. Total Knee Arthroplasty (TKA), aim is to relieve pain in an osteoarthritic knee, to improve the functional range of movements, and thereby improve the quality of life, of the patient. In this study, which was specically done for women patients with primary tri-compartmental osteoarthritis of the knee, the implant design for total knee arthroplasty was either “Standard CR Flex Knee” or “Gender-Specic CR High-Flex Knee”. This prospective study had a recruitment period of 2 years and a minimum follow-up period of 1 year and was done between March 2018 to February 2021. 23 female subjects aged between 51 to 80 years, were recruited in the “Standard CR Flex Knee” group and 25 female subjects aged between 51 to 80 years, were recruited in the “GenderSpecic CR High-Flex Knee” group. 60.42% (n=29) had a right sided involvement and remaining 39.58% (n=19) had a left sided involvement. Post-operative Knee Society Clinical Rating System (KSS), mean clinical outcome for “Standard CR Flex” and “Gender-Specic CR High-Flex Knee” were scored as 87.5 and 92.0 points respectively. With regard to the mean functional outcome, as per KSS both the groups averaged 85.0 points. Thus, this study could not establish any potential additional benets, by opting for the “Gender-Specic CR High-ex knee prosthesis”. Both the “Standard CR Flex Knee” and the “Gender-Specic CR High-Flex Knee” TKA yielded nearly similar clinico-functional outcomes.

The High Flex Total Knee Arthroplasty\u2014Higher Incidence of Aseptic Loosening and No Benefit in Comparison to Conventional Total Knee Arthroplasty: Minimum 16-Years Follow-Up Results

PurposeThis prospective randomized study compares the clinical and radiographic long-term results at least 16 years after total knee arthroplasty (TKA) between a mobile-bearing high flex and a fixed-bearing posterior-stabilized knee.MethodsIn 2000, we included 60 patients who underwent a TKA. Patients were divided into two groups. At the time of the follow-up after a minimum of 16 years (16.5 years ± 0.6), 16 patients had died for causes unrelated to the operation, 15 were lost to the follow-up. Five patients of the high flex group had a revision. The final evaluation included the hospital for special surgery score (HSS) and radiographs. Using the X-rays and the Knee Society Roentgenographic Evaluation and Scoring System, radiolucent lines and the maximal knee flexion were determined.ResultsNo significant differences between the two groups were found. The mean HSS score of LPS group patients was 87.9 (± 10.6) points and that of the high flex group was 93.1 (± 7.4) points. Five patients of the high flex group had undergone a reoperation. One knee was revised for painful mid-flexion instability and the others for symptomatic aseptic loosening of the components.ConclusionThe long-term follow-up does not show any clear benefits and even a higher incidence of implant loosening using the mobile-bearing high-flex knee.

Increasing posterior condyle cut for high-flex knee prosthesis may injure popliteus tendon origin: A comparison between real clinical setting and cadaveric study

BackgroundHigh-flex total knee prosthesis designs were proposed to improve flexion in total knee replacement (TKA). One of high-flex features is increasing posterior condyle cut which put popliteal tendon in higher risk of injury and may result in gap changes. MethodsPrevalence of popliteus footprint injuries were compared between conventional and high-flex TKA in real clinical setting. Thirty-six popliteal origin sites from eighteen fresh cadavers were measured distances between the posterior rim of popliteal tendon origin and posterior border of the lateral femoral condyle (distance A) using digital “Vernier caliper”. The mean distances were compared to posterior condyle thickness of different prosthesis designs. ResultsThe prevalence of posterior popliteus footprint injury was significantly higher in high-flex TKA compared to the conventional design TKA (17.8% vs 3.5%, p =0.005). The mean of distance A on the right knee was 9.59 mm (6.03-12.70) while the mean of distance A on the left knee was 9.13 mm (5.80-11.07). Posterior condyle thickness of the femoral prostheses varies upon their design and size from 7.4 to 10 mm for conventional model and from 8.2 to 12.5 mm for high-flex design. Possibilities of popliteal tendon injury during posterior condyle bone cut was at least 16.7% for conventional model and 27.8% for the high-flex design. ConclusionHigh-flex TKA prosthesis with thicker posterior condyle relates to higher possibility of popliteal tendon origin injury compared to standard one.

Functional outcome of single stage bilateral total knee replacement measured using oxford knee score

Arthritis of the knee joint is one of the most common cause of knee pain in middle age and elderly population. Among all, osteoarthritis remains the most common cause, followed by rheumatoid arthritis and other types of inflammatory arthritis. Though medical management remains the most common modality of treatment, patient with severe arthritis see total knee replacement as the definitive way to improve their quality of life. Bilateral total knee replacement in one stage has an advantage of single hospital admission, shorter rehabilitation and is less expensive. But till recently single stage bilateral total knee replacement was in limited vogue due to fear of the perioperative complications. This study was done to evaluate the functional outcome of this surgery. AimTo study the clinical and functional outcome in a series of 101 patients who were operated for single stage bilateral total knee replacement using oxford knee score. Materials and methodsThe study is a prospective 1 year pilot study involving a series of 101 consecutive patients who were operated for single stage bilateral total knee replacement using Optetrak posterior stabilised high flex knee system (Exatech). Inclusion criteria were patients with bilateral osteoarthritis who underwent single stage bilateral total knee replacement. All patients underwent a pre and postoperative evaluation using oxford knee score at 3rd and 12th month. ResultThe mean age of our study population was 65.06 ± 7.53, 73.3% were female. The mean duration of hospital stay was 7.02 ± 0.346. The mean preoperative oxford knee score improved from 11.47 preoperatively to 35.57 three months postoperative. At one year the mean oxford knee society score was 46.31. The mean change in oxford knee score from preoperative to 3 month postoperative and from 3 month postoperative to 1 year postoperative was statistically significant. DiscussionSingle stage bilateral total knee arthoplasty improves the quality of life in patients with severe osteoarthritis as reflected in oxford knee score.

Gender comparison of clinical outcomes post high-flex total knee arthroplasty

Background: Although it is normally perceived that knee morphometry contrasts exist amongst the female as well as male populations, the literature normally disproves the need for gender specific totalknee prosthesis clinically. It was noted that standard/unisex knee performs alike or better in female than male. As of late, high flex knees became accessible, that mechanically accommodate raised flexion but not many studies have contrasted these devices’ results in male and female to find out if there is any gender based contrast. Methods and Results: We aimed to compare midterm functional outcomes as well as survivorship of large cohorts of male and female acquiring Cruciate Retaining (CR) high flex knee in 744 females (994 knees) and 469 males (641 knees). Kaplan Meier survival analysis was similar in genders, i.e., 97.5 % (95% CI: 96.7-98.9%) at 5.8 y for males and 97.5% (95% CI: 95.9-99.2%) at 5.9 y for females. Mean improvement in Knee Society score (KSS) Knee and KSS Function for male and female (51.2 vs. 45.3; 26.7 vs. 22.8) and Short Form Health Survey (SF12) Mental as well as Physical scores (0.3 vs. 2.3; 14.2 vs. 13.2) were identical with contrasts irrelevant clinically. Conclusion: During stratification of motion results by preoperative values, we discovered nearly similar differences between preop and postop Range of Motion (ROM) as well as Peak Flexion (PF) values for both male and female. This demonstrates that a specific high flex knee configuration had similar clinical efficacy in both genders.

The new method of adjusting the gap for UKA

In unicompartmental knee arthroplasty (UKA), extension gap commonly decreases after inserting the trial components. As most of UKA technique incorporates the fixture of implants using bone cement, it is likely that the gap decreases further when inserting the actual implants. We performed a new additional procedure that enables a precise adjustment of the extension gap. Thirty-two patients who had undergone UKA (ZIMMER Unicompartmental High-Flex Knee System, Zimmer®, Warsaw) using the spacer block technique at our hospital in 2013 were reviewed. Ten cases had difficulties in achieving full extension after the trial implants were inserted, and hence, a new procedure of longitudinal incision between the medial collateral ligament and the posterior capsule was performed. This additional method created a mean increase of 3mm of the extension gap, and facilitated the knee to extend completely. There were no cases that had an increase in the flexion gap. Previously, a tibial osteotomy was added in such cases, but this had a risk of increasing not just the extension gap but also the flexion gap. This method is a valid technique for precise adjustments, and could also be applied to patients with severe flexion contracture to treat by UKA.

Retrospective comparison of functional and radiological outcome, between two contemporary high flexion knee designs

Introduction: Patient satisfaction after total knee replacement (TKR) depends on the amount of pain relief and the functional activities achieved. An important criterion of good functional outcome is the amount of flexion achieved and whether the patient can manage high flexion activities. In order to increase the amount of safe flexion, various implant designs have been developed. This study aims to compare the outcome after TKR using two contemporary high flexion knee designs: Sigma CR150 High Flex Knee prosthesis (Depuy, Warsaw, Indiana) and NexGen High Flex Knee prosthesis (Zimmer, Warsaw, Indiana). Material: A retrospective study was conducted with 100 cases of each design and their functional and radiological outcome was assessed after two years of follow-up. Results: The two groups had comparable results in terms of subjective satisfaction, range of motion achieved and radiological outcome. Depuy group fared better than Zimmer in terms of functional outcome (modified Oxford knee score). Conclusion: Depuy group was found to have fared better than Zimmer in terms of functional outcome. However, it is very difficult to rate one design above the other based on our small sample size and short duration of follow-up.

Clinical Results of Lateral Unicompartmental Knee Arthroplasty: Minimum 2-Year Follow-up.

BackgroundWe investigated the clinical results and early complications after lateral unicompartmental knee arthroplasty (UKA) using the Zimmer unicompartmental high-flex knee (ZUK) prosthesis with a minimum follow-up of 2 years.MethodsTwenty-seven patients (30 cases) who underwent lateral UKA with the ZUK prosthesis between January 2011 and February 2014 were selected for this study. The mean age of the patients was 63.3 years at the time of surgery, and the mean followup was 3 years and 2 months (range, 24 to 48 months). A retrospective investigation method was used to evaluate the clinical and radiographic results with use of the Knee Society (KS) clinical rating system and plain radiography.ResultsThe mean KS pain score was improved from 17.9 points (range, 10 to 30 points) preoperatively to 40.5 points (range, 30 to 45 points) at the final follow-up (p < 0.001). The mean KS knee score and function score significantly increased from 63.2 points (range, 48 to 70 points) and 68.6 points (range, 35 to 80 points), respectively, preoperatively to 86.0 points (range, 74 to 95 points) and 92.4 points (range, 60 to 100 points), respectively, at the final follow-up (p < 0.001). The mean range of motion of the knee was recovered from 127.1° (range, 110° to 135°) preoperatively to 131.6° (range, 120° to 135°) at the final follow-up. The mean tibiofemoral angle changed from 6.2° of valgus (range, 0.1° to 11.4° of valgus) preoperatively to 3.4°of valgus (range, 0.2° to 9.5° of valgus) at the final follow-up. The overall results classified based on the KS knee score were "excellent" in 21 cases and "good" in 8 cases. Revision total knee arthroplasty was required in one case because of consistent pain on the medial side of the knee after surgery.ConclusionsThe early clinical results of lateral UKA using the ZUK prosthesis were satisfactory for improvement of pain, knee score, function score, and recovery of knee motion. Therefore, the lateral UKA could be a useful method in the treatment of osteoarthritis in the lateral compartment of the knee. Long-term survivorship remains to be confirmed through ongoing follow-up.

Factors affecting the achievement of Japanese-style deep knee flexion after total knee arthroplasty using posterior-stabilized prosthesis with high-flex knee design

BackgroundAchievement of very deep knee flexion after total knee arthroplasty (TKA) can play a critical role in the satisfaction of patients who demand a floor-sitting lifestyle and engage in high-flexion daily activities (e.g., seiza-sitting). Seiza-sitting is characterized by the knees flexed >145º and feet turned sole upwards underneath the buttocks with the tibia internally rotated. The present study investigated factors affecting the achievement of seiza-sitting after TKA using posterior-stabilized total knee prosthesis with high-flex knee design. MethodsSubjects comprised 32 patients who underwent TKA with high-flex knee prosthesis and achieved seiza-sitting (knee flexion >145º) postoperatively. Another 32 patients served as controls who were capable of knee flexion >145º preoperatively, but failed to achieve seiza-sitting postoperatively. Accuracy of femoral and tibial component positions was assessed in terms of deviation from the ideal position using a two-dimensional to three-dimensional matching technique. Accuracies of the component position, posterior condylar offset ratio and intraoperative gap length were compared between the two groups. ResultsThe proportion of patients with >3º internally rotated tibial component was significantly higher in patients who failed at seiza-sitting (41%) than among patients who achieved it (13%, p=0.021). Comparison of intraoperative gap length between patient groups revealed that gap length at 135º flexion was significantly larger in patients who achieved seiza-sitting (4.2±0.4mm) than in patients who failed at it (2.7±0.4mm, p=0.007). Conversely, no significant differences in gap inclination were seen between the groups. ConclusionsFrom the perspective of surgical factors, accurate implant positioning, particularly rotational alignment of the tibial component, and maintenance of a sufficient joint gap at 135º flexion appear to represent critical factors for achieving >145º of deep knee flexion after TKA.

Clinical outcomes after high-flex versus conventional total knee arthroplasty.

To compare clinical outcomes after high-flex versus conventional total knee arthroplasty (TKA). A systematic review and meta-regression were performed to compare post-operative outcomes between the two types of prostheses. Relevant randomized controlled trials were identified from MEDLINE and Scopus up to November, 2014. Fourteen of 369 studies were eligible; 14, 7, 6, 5, 3, 12 and 7 studies were included in the pooling of maximum knee flexion, Knee Society Knee Score (KS), Knee Society Function Score (FS), Hospital for Special Surgery score (HSS), short-form (SF) physical activity score, post-operative complications (DVT, fractures, infection) and revision TKA, respectively. The high-flex TKA had 1.97° [95% confidence interval (CI) 0.37, 3.57], -0.86 (95% CI -1.65, 0.07) and -1.34 (-2.57, -0.11) higher mean maximum knee flexion, KS and FS when compared to conventional TKA. However, there were non-significant differences in HSS, SF-36 (physical), complications and revision TKA. This study suggests that there are improvements in post-operative knee range of motion and knee scores in high-flex TKA implants when compared to conventional TKA implants; however, the difference was very small and therefore might not have any clinical impact. Therefore, conventional TKA can be used as a substitute. However, cost-effective analysis should be performed to make appropriate selections in the future. There are no statistically significant differences in terms of HSS, quality of life, complications and revisions between the groups. I.

Clinical Outcomes in Men and Women following Total Knee Arthroplasty with a High-Flex Knee: No Clinical Effect of Gender.

While it is generally recognized that anatomical differences exist between the male and female knee, the literature generally refutes the clinical need for gender-specific total knee prostheses. It has been found that standard, unisex knees perform as well, or better, in women than men. Recently, high-flex knees have become available that mechanically accommodate increased flexion yet no studies have directly compared the outcomes of these devices in men and women to see if gender-based differences exist. We retrospectively compared the performance of the high-flex Vanguard knee (Biomet, Warsaw, IN) in 716 male and 1,069 female knees. Kaplan-Meier survivorship was 98.5% at 5.6–5.7 years for both genders. After 2 years, mean improvements in Knee Society Knee and Function scores for men and women (50.9 versus 46.3; 26.5 versus 23.1) and corresponding SF-12 Mental and Physical scores (0.2 versus 2.2; 13.7 versus 12.2) were similar with differences not clinically relevant. Postoperative motion gains as a function of preoperative motion level were virtually identical in men and women. This further confirms the suitability of unisex total knee prostheses for both men and women.

Joint gap assessment with a tensor is useful for the selection of insert thickness in unicompartmental knee arthroplasty

BackgroundThe success of unicompartmental knee arthroplasty relies on a lot of factors such as correct osteotomy and proper soft-tissue tensioning. A selection of insert thickness depends solely on the surgeon's subjective feeling. Recently, a tensor that is designed to assess soft tissue balance during unicompartmental knee arthroplasty has been developed. The purpose of this study was to compare the component gap throughout the range of motion among different distraction forces and examine the correlation between the component gap and the insert thickness. Methods30 cases of 29 patients were included. All the patients received a conventional medial Zimmer Unicompartmental High Flex Knee System. Using a tensor under 10, 20, 30, and 40lb distraction forces, after femoral component placement, the component gaps were assessed throughout the range of motion. The correlations between the component gap and the insert thickness selected were examined. FindingsThe component gap showed the same kinematic pattern among the different distraction forces and the value increased in proportion to the increase of the distraction force in unicompartmental knee arthroplasty. The insert thickness in unicompartmental knee arthroplasty was found to have a strong positive correlation with the component gap from 10 to 45° of knee flexion with a distraction force of more than 20lb InterpretationWith the use of the tensor, surgeons can quantify the component gap and objectify their insert thickness decision compared with the use of tension gauge.

VANGUARDTM RP High-Flex人工膝関節の術後短期成績とその手技の有用性

VANGUARDTM RP High-Flex人工膝関節の術後短期成績とその手技の有用性

Comparable short-term results seen with standard and high-flexion knee arthroplasty designs in European patients

PurposeIn a prospective study we evaluated outcomes of total knee arthroplasty (TKA) procedures in 62 patients with a follow up of 12 months to test our hypothesis that high-flexion CR (cruciate retaining) TKA provides a better range of motion and better outcome than standard CR design in Central European patients with their special problems and demands. MethodsPatients were randomly divided into two groups (high flex vs. standard). The outcome was determined by measuring maximum knee flexion and using the KS-score and the SF-36 score. ResultsAfter 12 months ability to flex the knee significantly improved in both groups to 115° (SD 11) in the high flex group versus 119° (SD 12) in the standard group. There was no difference between the designs regarding maximum flexion (p = 0.78). Overall clinical rating scores significantly improved in both groups, but there was no difference between groups at one year after surgery (p (KSS) = 0.7 and p (SF-36) = 0.63). KS-score values improved from 25 points to 89 points for standard TKAs and from 20 points to 90 points for high flex TKAs. SF-36-score “Physical Functioning” values improved from 33 points to 66 points for standard TKAs and from 27 points to 63 points for high flex TKAs. ConclusionOur results confirm known good results of the procedure and suggest that the benefit of high flex knee designs is similar to standard knee designs one year after index surgery. Further studies are required to evaluate long-term results of both designs.

Factors affecting range of motion in total knee arthroplasty using high flexion prosthesis: A prospective study

Background:High flexion implants have been reported to provide better range of motion (ROM). The few studies analyzing the factors affecting the ROM are scarce. This study aims to find the factors that affect ROM when using a high flex knee design (INDUS knee).Materials and Methods:Two hundred and fifty three consecutive patients of total knee arthroplasty (TKA) done by using INDUS knee prosthesis between Sept 2008 and Sept 2009 were included in the study. The cases with osteoarthritis (OA) and Rheumatoid arthritis (RA) were included in study. 5 patients were lost to followup and 248 patients (267 knees, 19 bilateral, 221 OA, and 46 RA) were analyzed for the following factors – sex, age, body mass index (BMI), preoperative ROM, flexion deformity, preoperative total knee score and functional score, time of tourniquet release and patella resurfacing. Subgroup classification using above factors was performed and statistical analysis of effect of all the above factors on final knee ROM was done. Assessment was done preoperatively and at 3 months, 6 months and 1 year postoperatively. The final outcome evaluation was done at one year followup.Results:The mean age was 68.2 years (range 40-89 years) with 79 males and 189 females. The mean knee range improved from 97.62 ± 11° to 132 ± 8°. Factors that positively affect ROM of INDUS knee prosthesis at the end of 1 year were preoperative ROM, total knee score and functional score, and diagnosis of osteoarthritis, whereas BMI, preoperative flexion deformity has a negative influence on final flexion at the end of 1 year. Age and gender of the patients, patella resurfacing, and use of two different tourniquet protocols did not affect the final outcome.Conclusion:Preoperative ROM and preoperative functional status are the most important factors affecting final range. Patients should be counseled accordingly and made to understand these factors.

Does the new generation of high-flex knee prostheses improve the post-operative range of movement?

A new generation of knee prostheses has been introduced with the intention of improving post-operative knee flexion. In order to evaluate whether this goal has been achieved we performed a systematic review and meta-analysis. Systematic literature searches were conducted on MEDLINE and EMBASE from their inception to December 2007, and proceedings of scientific meetings were also searched. Only randomised, clinical trials were included in the meta-analysis. The mean difference in the maximum post-operative flexion between the 'high-flex' and conventional types of prosthesis was defined as the primary outcome measure. A total of five relevant articles was identified. Analysis of these trials suggested that no clinically relevant or statistically significant improvement was obtained in flexion with the 'high-flex' prostheses. The weighted mean difference was 2.1° (95% confidence interval -0.2 to +4.3; p = 0.07).

The Relationship between Pre- and Postoperative Range of Motion Utilizing Three Cruciate-Retaining Total Knee Prostheses

We prospectively examined the relationship between pre- and postoperative range of motion utilizing three cruciate retaining knees with various mechanical flexion potentials, i.e., two at about 130°–135° (one with posterior lip and the other without) and the third at about 140°–145°. All groups demonstrated mean flexion and range of motion of 116°–122° at one year. Combining data from the three cohorts, patients with the following preoperative flexion values achieved the indicated mean changes (increases) in flexion at one year: < 90° flexion (Δ 23.6°), 91°–105°flexion (Δ 19.3°), and > 105° flexion (Δ 1.8°)). Postoperative improvement was inversely related to preoperative flexion. The high flex knee yielded the best improvement in range of motion (9.7°increase) in the highest flex preoperative group compared to that of the other knees (−7.4° to 2.9°). Hence, a high flex knee design seems to be important in high preoperative range of motion patients obtaining an increase in the postoperative range of motion rather than possible regression.

In Vivo Determination of Kinematics for Subjects Having a Zimmer Unicompartmental High Flex Knee System

The objective of this study was to determine the in vivo kinematics during weight-bearing and non–weight-bearing activities for subjects with a unicompartmental knee arthroplasty (UKA) designed for high flexion and implanted with minimally invasive techniques. A total of 30 UKAs implanted in 18 patients were analyzed. All patients were implanted with a medial Zimmer Unicompartmental High Flex Knee System (Zimmer Inc, Warsaw, Ind). Under fluoroscopic surveillance, each patient performed weight-bearing deep knee bend, normal gait, and passive flexion. The kinematics of the medial UKA was determined using a 3-dimensional model registration technique. On average, the implant experienced posterior femoral rollback and normal axial rotation during flexion. However, the kinematic patterns for each patient were not consistent, and the variability was high during flexion and stance phase of gait.

Minimally Invasive Quadriceps-Sparing Posterior Stabilized Total Knee Arthroplasty

Quadriceps-sparing total knee arthroplasty is a minimally invasive surgery for total knee replacement. The first procedures were performed by the senior author and by Thomas M. Coon, MD, in February 2002. The instruments and the surgical technique have gradually improved, and there is now a minimally invasive tibial implant (MIS Tibia, Zimmer Orthopaedics, Warsaw, IN) that facilitates insertion of the prosthesis. This article will outline the procedure as performed for a posterior stabilized total knee design (Legacy High Flex Knee, Zimmer Orthopaedics). The results show less blood loss, less pain, a shorter hospital stay, faster recovery of range of motion, and faster return to normal activity.

High Flex Knee Arthroplasty and Range of Motion

Purpose: The aim of this prospective study was to determine which factors are predictive of the post operative range of motion and to evaluate the short-term clinical results after total knee arthroplasty using The Nexgen Legacy Knee LPS-Flex fixed bearing knee system replacement. Materials and Methods: A total of 67 patients (101 knees) were enrolled in this study. 101 knees were operated on using the LPS-Flex fixed bearing knee system replacement. The same surgeon performed the surgery between December 2001 and March 2002. The patients’ages ranged from 52 to 77 years, with an average of 68.4 years. Preoperatively the factors considered were the age of the patient, gender, the body mass index, the flexion contracture and further flexion possible. The factors considered postoperatively were patellar tilting and displacement, the postoperative knee and functional score, and a varus deformity. The patients were followed up once every 3 month for up to 2 years. Results: At the latest follow-up, the average flexion in this series was (range, -). Thirty knees could attain more than flexion. Twenty patients could comfortably kneel down. The 53 patients could sit cross-legged. The eleven knees could attain less than of flexion at the final follow-up. There was a significant improvement in flexion at each successive review 12 months after surgery. The most important factor that influenced the range of motion after an arthroplasty was the preoperative range of flexion. The average Knee Society knee score was 90 points (range, 80-100), and the function score was 91 points (range, 45-100). Conclusion: A total knee arthroplasty with LPS-flex showed an excellent range of motion and satisfactory early clinical results. The most important factor that influences the range of motion after an arthroplasty is the preoperative range of flexion.