Mid-term survivorship of Mini-keel™ versus Standard keel in total knee replacements: Differences in the rate of revision for aseptic loosening

Relationship between cement penetration and incidence of a radiolucent line around the tibia 2 years after total knee arthroplasty: A retrospective study

OBJECTIVES

Cement penetration (CP) plays a key role in implant stability for cemented total knee arthroplasty (TKA) and the radiolucent line (RLL) >2mm is a preliminary sign for loosening of components. However, the direct relationship between CP and the frequency of RLL >2 mm is unclear and the best cutoff value for CP to prevent RLL >2 mm also remain unclear. This study aimed to investigate this relationship between CP and RLL and to determine the clinical cutoff value for tibial CP in patients 2 years after TKA.

METHODS

This retrospective study investigated 157 knees from 123 patients with osteoarthritis who underwent cemented TKA. The CP and RLL immediately after TKA and the RLL 2 years after TKA were measured for the medial, lateral, anterior, and posterior tibial baseplate zones. Receiver operating characteristic (ROC) curves were constructed to determine the best cutoff values for CP.

RESULTS

RLL >2 mm was not observed just after TKA. RLL >2 mm was observed in any tibial baseplate zone in 22 knees from 20 patients (RLL+ group) and was not observed in the remaining (RLL- group) 2 years after TKA. Mean CP for all zones was significantly higher in the RLL- group (2.5 ± 1.1 mm) than in the RLL+ group (1.7 ± 0.6 mm; P<0.001). RLL >2 mm was seen in 21 knees in the medial zone, 9 knees in the lateral zone, 8 knees in the anterior zone, and 3 knees in the posterior zone. CP values with RLL >2 mm were significantly lower than those without the RLL at the medial, anterior, and posterior tibial baseplate zones. The best cutoff values from the ROC curve of CP in each zone were between 1.1 mm and 2.1 mm.

CONCLUSIONS

The depth of the CP directly affects the incidence of RLL >2 mm. The best cutoff value for tibial CP to prevent RLL >2 mm is 2.1 mm.

Tibial implant design in primary TKA: retrospective comparison of two designs for the occurrence of radiolucent lines and aseptic loosening

INTRODUCTION

The purpose of this retrospective study was to study the effect of tibial implant design on the occurrence of radiolucent lines (RLLs) and aseptic loosening (AL) by comparing two different total knee arthroplasty (TKA) designs.

MATERIALS AND METHODS

Two types of total knee arthroplasty, different for tibial shape, size and keel design were compared, 255 for the first and 774 for the second. The occurrence of RLLs and radiological signs of micro- and macro-mobility and aseptic loosening was analyzed. Demographic data were compared, as well as the type and rate of RLLs, occurrence of aseptic loosening and the presence of potential risk factors.

RESULTS

The first implant design is morphometric and has a squarer keel than the second implant TKA. The overall rate of RLLs was similar (21% vs 23%), despite of a significantly lower rates of radiological signs of macro-mobility of the tibial component with the first implant (2% vs 17%). Survivorship of both designs was overall comparable (99.6% vs 98.8 %) the first implant group had more potential risk factors for poor bone quality than the second group (p < 0.05).

CONCLUSION

A morphometric design is more anatomic and offers better bone coverage of the epiphyseal tibial surface. RLLs, as a sign of implant micro-mobility, were equally present in both designs. Radiological signs of macro-mobility at the metaphysis were less frequently observed in squared keel design. The morphometric implant did not show improved survivorship compared with a symmetric implant.

LEVEL OF EVIDENCE

III.

Stemmed Versus Nonstemmed Tibia in Primary Total Knee Arthroplasty: A Similar Pattern of Aseptic Tibial Loosening in Obese Patients with Moderate Varus. 5-Year Outcomes of a Randomized Controlled Trial

Obesity is linked to early tibial tray failure after primary total knee arthroplasty (TKA) for osteoarthritis (OA), especially in patients with preoperative varus. This study compared standard and stemmed tibiae TKAs in patients with class I and II obesity with varus deformity. Between April 2013 and June 2020, a prospective study was conducted including patients with end-stage OA, body mass index between 30 and 40 kg/m2, and varus <15 degrees. Patients were randomly assigned to TKAs with either standard or long-stemmed tibiae and evaluated 5 years after surgery using the Knee Society Scoring (KSS). The knee society and modified radiographic evaluation systems were used for radiological evaluation. In total, 264 TKAs were performed in 264 patients (134 in the standard group and 130 in the stemmed group). The mean preoperative hip-knee-ankle angles for the standard and stemmed groups were 8.2 ± 3.2 degrees/varus and 9 ± 2.9 degrees/varus, respectively (p = 0.2), which improved to 5.1 ± 3 degrees/valgus and 5 ± 3.5 degrees/valgus after surgery (p = 0.52). There was no statistically significant difference between the objective KSS (92 vs. 92.9; p = 0.84) and the functioning KSS (73.4 vs. 74.8; p = 0.28). There were no aseptic loosening cases or radiographic differences. In-group analysis revealed significant outcomes differences in both groups if preoperative varus was >10 degrees irrespective of the stem design (p < 0.0001). Complications occurred in two patients; one with a late infection and one had a stem-related tibial fracture. Standard tibia TKAs yielded comparable results in obese patients to long-stemmed tibias. No aseptic tibial loosening was observed regardless of stem type, and worse clinical outcomes were associated with greater varus. CLINICAL TRIAL REGISTRY::  registered at http://www.researchregistry.com (researchregistry5717).LEVEL OF EVIDENCE: II; a prospective randomized trial.

Pressurized carbon dioxide lavage reduces the incidence of a radiolucent line around the tibial component two years after total knee arthroplasty

Introduction

In cemented total knee arthroplasty (TKA), pressurized carbon dioxide (CO₂) lavage prior to cement fixation can eliminate debris at the bone-cement interface and is considered effective for increasing cement penetration and preventing aseptic loosening. Regarding the risk of a preliminary diagnosis of implant loosening, a radiolucent line (RLL) is a valuable sign. The purpose of this study was to compare the incidence of a tibial RLL at 2 years after TKA with and without pressurized CO₂ lavage.

Methods

This is a retrospective study. One hundred knees from 98 patients were enrolled in this study. TKA was performed without pressurized CO₂ lavage (CO₂− group) for the first 47 knees, and with pressurized CO₂ lavage (CO₂+ group) for the next 53 knees. The depth of cement penetration was measured just after surgery, and the incidence of tibial RLL > 2 mm at 2 years after TKA was determined.

Results

Significant differences between groups were not seen regarding pre- and postoperative clinical factors. The depth of cement penetration in each area was significantly higher in the CO₂+ group. The frequency of knees with RLL > 2 mm was significantly lower in the CO₂+ group than in the CO₂− group (p < 0.001).

Conclusions

Pressurized CO₂ lavage improved cement penetration and decreased the incidence of tibial RLL > 2 mm at 2 years after TKA.

High rate of tibial debonding and failure in a popular knee replacement

Aims

Total knee arthroplasty (TKA) is a common and safe orthopaedic procedure. Zimmer Biomet's NexGen is the second most popular brand of implant used in the UK. The primary cause of revision after the first year is aseptic loosening. We present our experience of using this implant, with significant concerns around its performance with regards early aseptic loosening of the tibial component.

Methods

A retrospective, single-surgeon review was carried out of all of the NexGen Legacy Posterior Stabilized (LPS) TKAs performed in this institute. The specific model used for the index procedures was the NexGen Complete Knee System (Legacy Knee-Posterior Stabilized LPS-Flex Articular Surface, LPS-Flex Femoral Component Option, and Stemmed Nonaugmentable Tibial Component Option).

Results

Between 2013 and 2016, 352 NexGen TKAs were carried out on 331 patients. A total of 62 TKAs have been revised to date, giving an all-cause revision rate of 17.6% at a minimum of five years. Three of these revisions were due to infection. Overall, 59 of the revisions were performed for aseptic loosening (16.7%) of the tibial component. The tibial component was removed intraoperatively without instrumentation due to significant tibial debonding between the implant-cement interface.

Conclusion

While overall, we believe that early aseptic loosening is multi-factorial in nature, the significantly high aseptic revision rate, as seen by an experienced fellowship-trained arthroplasty surgeon, has led us to believe that there is a fundamental issue with this NexGen implant design. Continued implant surveillance and rigorous review across all regions using this particular implant is warranted based on the concerning findings described here.

Cite this article: Bone Jt Open 2022;3(6):495–501.

Assistive technologies in knee arthroplasty: fashion or evolution? Rate of publications and national registries prove the Scott Parabola wrong

PURPOSE

Most opponents of assistive technologies in orthopedic surgery consider them as a marketing ruse or fashion. Our hypothesis was that many innovations in modern knee arthroplasty are not following the Scott Parabola. This parabola represents the visual curve of a procedure or therapy showing great promise at the beginning, becoming the standard treatment after reports of encouraging results, only to fall into disuse due to adverse outcome reports. This study aimed to assess the interest in these assistive technologies by (1) their number of publications/year and (2) their actual surgical use reported in the National Joint Registries.

METHODS

The search was performed through PubMed, EMBASE, and MEDLINE databases from 1997 to 2021 inclusive to identify all available literature that described the use and results of assistive technologies or new surgical techniques in knee arthroplasty. In the Australian and Norwegian registries, the number of cases performed with these techniques in knee arthroplasty has been quantified year by year.

RESULTS

Following the initial online search, a total of 4085 articles was found. After the assessment mentioned above, 2106 articles were included in the study. The orthopedic techniques assessed in this study are not following the "Scott's parabola" in the literature. Computer-assisted knee arthroplasty and patient-specific instrumentation have increased quickly to have reached a plateau, with a stable number of publications over the last 6 years. The number of publications concerning robotic surgery, accelerometers and sensors continue to rise. In the Australian registry, the proportion of primary TKA performed by computer-assisted systems increased from 2.4% in 2003 to 32% in 2019. In the Norwegian registry, the proportion of computer-assisted TKA remained between 8 and 12% of primary TKA since 2007.

CONCLUSION

Most of the innovations in modern knee arthroplasty are not following the Scott Parabola. After a fast rise, these techniques do not disappear but continue to evolve. Their evolution is synergistic, and techniques appeared to be linked to each other's. Despite persisting concerns about the cost-efficiency of assisting technologies in knee arthroplasties, the interest and use do not decrease and seems to be directly linked to an exponential increase in interest for a better understanding of alignment targets and improved functional recovery.

Cement debonding behaviors of the various tibial components of the ATTUNE knee system and its predecessors: Is a cement-in-cement revision an alternative?

BACKGROUND

Aseptic loosening remains one of the most common causes of revision of the tibial component for total knee arthroplasty. A stable bond between implant and cement is essential for appropriate long-term results. The aim of our in vitro study was to investigate the maximum failure load of tibial ATTUNE prosthesis design alternatives compared with a previous design. In addition, cement-in-cement revision was considered as a potential strategy after tibial component debonding.

METHODS

The experimental investigations of the maximum failure load of the implant-cement interface were performed under optimal conditions, without potential contamination. We compared the designs of the tibial components of the ATTUNE, ATTUNE S+ and P.F.C. Sigma. In addition, we investigated the cement-in-cement revision for the ATTUNE knee system replacing it with an ATTUNE S+.

RESULTS

The maximum failure load showed no significant difference between P.F.C. Sigma and ATTUNE groups (P = 0.087), but there was a significant difference between the P.F.C. Sigma and the ATTUNE S+ groups (P < 0.001). The analysis also showed a significant difference (P < 0.001) between the ATTUNE and the ATTUNE S+ groups for the maximum failure load. The ATTUNE S+ cement-in-cement revision group showed a significant higher failure load (P < 0.001) compared with the P.F.C. Sigma and ATTUNE groups. No significant differences (P = 1.000) were found between the ATTUNE S+ cement-in-cement and ATTUNE S+ group.

CONCLUSION

Based on these results, we found no design-specific evidence of increased debonding risk with the ATTUNE and ATTUNE S+ components compared with the P.F.C Sigma. Furthermore, the cement-in-cement revision seems to be an alternative for the revision surgery.

Outcomes of total knee replacement with the use of a NexGen MIS Tibial Component (Mini-keel) : a systematic review

NexGen MIS Tibial Component (Mini-keel) is a tibial component specially developed for minimally invasive surgery in total knee replacement (TKR), and the size limitations of its design and the modular system could affect tibial fixation strength, however, this has not been precisely evaluated thus far. This study aimed to systematically review the literature describing the outcome following TKR with the use of a Mini-keel. Electronic searches of databases were undertaken in July 2019 by two experienced orthopaedic surgeons according to the PRISMA guidelines for literature describing the outcomes of TKR with the use of a Mini-keel. Quality of studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. The initial search found a total of 623 studies from all the databases. Seven studies met all the inclusion criteria and were eligible for critical appraisal and quality assessment. In total, 2,198 cases were included in the systematic review. Thirty-five revision cases due to aseptic loosening were found from the systematic review. Two studies were negative about using a Mini-keel and three studies were positive about it, while the other two studies did not judge the quality of a Mini-keel. There have been conflicting conclusions among studies for the use of a Mini-keel. There remains a paucity of prospective cohort studies between TKRs with the use of a Mini-keel and those with the use of a conventional implant, which makes it difficult to determine the usefulness and reliability of this implant.

Early outcomes of a modern cemented total knee arthroplasty : is tibial loosening a concern?

AIMS

Recent total knee arthroplasty (TKA) designs have featured more anatomical morphologies and shorter tibial keels. However, several reports have raised concerns about the impact of these modifications on implant longevity. The aim of this study was to report the early performance of a modern, cemented TKA design.

METHODS

All patients who received a primary, cemented TKA between 2012 and 2017 with a minimum two-year follow-up were included. The implant investigated features an asymmetrical tibial baseplate and shortened keel. Patient demographic details, Knee Society Scores (KSS), component alignment, and the presence of radiolucent lines at final follow-up were recorded. Kaplan-Meier analyses were performed to estimate survivorship.

RESULTS

A total of 720 of 754 primary TKAs (95.5%) were included with a mean follow-up of 3.9 years (SD 1.3); 562 (78.1%) were cruciate-retaining and 158 (21.9%) were posterior-stabilized. A total of 11 (1.5%) required reoperation for periprosthetic joint infection and seven (1.0%) for aseptic tibial loosening (five cruciate-retaining, two posterior-stabilized). Loosening occurred at a mean of 3.3 years (0.9 to 6.5). There were no cases of loosening in the 33 patients who received a 14 mm × 30 mm tibial stem extension. All-cause survivorship was 96.6% at three years (95% confidence interval (CI) 95.3% to 98.0%) and 96.2% at five years (95% CI 94.8% to 97.7%). Survivorship with revision for aseptic loosening was 99.6% at three years (95% CI 99.1% to 100.0%) and 99.1% at five years (95% CI 98.4% to 99.9%). Tibial components were in significantly more varus in those with aseptic loosening (mean 3.4° (SD 3.7°) vs 1.3° (SD 2.0°); p = 0.015). There were no other differences in demographic, radiological, or surgical characteristics between revised and non-revised TKAs for aseptic loosening (p = 0.293 to 1.00). Mean KSS improved significantly from 57.3 (SD 9.5) preoperatively to 92.6 (SD 8.9) at the final follow-up (p < 0.001).

CONCLUSION

This is the largest series to date of this design of implant. At short-term follow-up, the rate of aseptic tibial loosening is not overly concerning. Further observation is required to determine if there will be an abnormal rate of loosening at mid- to long-term follow-up. Cite this article: Bone Joint J 2021;103-B(6 Supple A):51-58.

Aseptic Loosening at the Tibia in Total Knee Arthroplasty: A Function of Cement Mantle Quality?

BACKGROUND

Aseptic loosening remains one of the leading causes for failure of total knee arthroplasty (TKA). We sought to identify early radiographic measures that may associate with aseptic tibial component loosening, emphasizing systematic evaluation of the cement mantle.

METHODS

All TKA revisions from 2007 to 2015 with the primary indication of tibial aseptic loosening were identified using in an institutional implant retrieval database. After exclusion criteria, 61 TKAs comprised the study group. A matched control group of 59 TKAs that had not failed at a minimum of 3 years was identified for comparison. Radiographic analysis on all 6-week postoperative radiographs included angulation of components, cement penetration depth, and presence of radiolucency at the implant-cement and bone-cement interfaces. Groups were compared with Student's t-test, chi-squared test, and Mann-Whitney U-test. A final multivariable logistic regression model was formed for the outcome of aseptic loosening.

RESULTS

On multivariable analysis, failure was associated with a greater number of zones with cement penetration <2 mm (5.6 vs 3.4 zones, odds ratio [OR] 1.89, P < .001), increasing percent involvement of radiolucency at the implant-cement interface (8.7% vs 3.1%, OR = 1.15, P = .001), and increased varus alignment of the tibial component (1.5° vs 0°, OR = 1.35, P = .014). A greater number of zones with a radiolucent line at the bone-cement interface did not significantly associate (1.1 vs 0.3, P = .091).

CONCLUSION

Our results suggest that radiographic indicators of poor cement mantle quality associate with later aseptic loosening. This emphasizes the need for surgeons to perform careful cement technique in order to reduce the risk of TKA failure.

LEVEL OF EVIDENCE

III (Case-control).

High Incidence of Tibial Component Loosening After Total Knee Arthroplasty Using Ceramic Titanium-Nitride-Coated Mobile Bearing Prosthesis in Moderate to Severe Varus Deformity: A Matched-Pair Study Between Ceramic-Coated Mobile Bearing and Fixed Bearing Prostheses

BACKGROUND

We compared the incidence of aseptic component loosening and subsequent revision, and the survival rate between ceramic titanium-nitride-coated mobile bearing (MB) and fixed bearing total knee arthroplasties (TKAs) performed in patients with moderate to severe varus deformities.

METHODS

In total, 200 TKAs using advanced coated system posterior stabilized prostheses in varus deformity of mechanical axis >8° between 2012 and 2016 were retrospectively reviewed. One hundred MB (ceramic-m group) and 100 fixed bearing (ceramic-f group) prostheses were included. The matches were made according to preoperative demographics, range of motion, and severity of deformity. The mean follow-up period was not different (ceramic-m vs ceramic-f = 4.8 vs 5.1 years; P = .104). The incidence of revision TKA due to aseptic component loosening and the survival rate (failure: revision due to aseptic loosening) was investigated.

RESULTS

The incidence of revision TKA due to aseptic component loosening was 7 (7%) in the ceramic-m group and 1 (1%) in the ceramic-f group (P = .032). All cases of aseptic loosening occurred at the tibial component. The overall survival rate was 91.3% in the ceramic-m group and 98.9% in the ceramic-f group (P = .025).

CONCLUSION

Considering the higher revision incidence and lower survival rate due to tibial component loosening, caution should be taken in tibial component fixation when using advanced coated system MB prosthesis in moderate to severe varus deformity.

LEVEL OF EVIDENCE

III.

Comparison of mode of failure between primary and revision total knee arthroplasties

INTRODUCTION

Cognizance of common reasons for failure in primary and revision TKA, together with their time course, facilitates prevention. However, there have been few reports specifically comparing modes of failure for primary vs. revision TKA using a single prosthesis. The goal of the study was to compare the survival rates, modes of failure, and time periods associated with each mode of failure, of primary vs. revision TKA.

HYPOTHESIS

The survival rates, modes of failure, time period for each mode of failure, and risk factors would differ between primary and revision TKA.

MATERIAL AND METHODS

Data from a consecutive cohort comprising 1606 knees (1174 patients) of primary TKA patients, and 258 knees (224 patients) of revision TKA patients, in all of whom surgery involved a P.F.C^® prosthesis (Depuy, Johnson & Johnson, Warsaw, IN), was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 9.2 and 9.8 years, respectively.

RESULTS

The average 10- and 15-year survival rates for primary TKA were 96.7% (CI 95%,±0.7%) and 85.4% (CI 95%,±2.0%), and for revision TKA 91.4% (CI 95%,±2.5%) and 80.5% (CI 95%,±4.5%). Common modes of failure included polyethylene wear, loosening, and infection. The most common mode of failure was polyethylene wear in primary TKA, and infection in revision TKA. The mean periods (i.e., latencies) of polyethylene wear and loosening did not differ between primary and revision TKAs, but the mean period of infection was significantly longer for revision TKA (1.2 vs. 4.8 years, P=0.003).

DISCUSSION

Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision TKAs. Continuous efforts are required to prevent and detect the various modes of failure during long-term follow-up. Greater attention is necessary to detect late infection-induced failure following revision TKA.

LEVEL OF EVIDENCE

Case-control study, Level III.

Radiolucent lines are decreased at 3 years following total knee arthroplasty using trabecular metal tibial components

Objective To analyse location and frequency, and change over time, of radiolucent lines (RLLs) around trabecular metal tibial components in total knee arthroplasty (TKA). Methods Osteoarthritic knees in patients who had undergone TKA were retrospectively evaluated via analysis of RLLs on anteroposterior and lateral X-rays obtained at 2 and 6 months, and 1, 2 and 3 years following TKA. Results In 125 osteoarthritic knees from 90 patients (mean age, 75.0 ± 6.2; 21 male/69 female), frequency of RLLs around trabecular metal tibial components was generally highest at 2 and 6 months, and 1 year following TKA, then gradually decreased over the 3-year follow-up. Frequency of RLLs around trabecular metal tibial components was greater at the tip of the two pegs, particularly the medial peg, and around the pegs, versus other zones. No postoperative revisions were performed for loosening. Conclusions Over 3 years following TKA, RLLs were most frequently observed up to 1 year, then gradually decreased. RLLs were significantly more frequent in the medial peg zone and zones close to the medial peg than in other zones.

Mid-term survivorship of cruciate-retaining versus posterior-stabilized total knee arthroplasty using modular mini-keel tibial implants

Background

Reports of diverse outcomes in modular mini-keel tibial componentry for total knee arthroplasty (TKA) have raised concerns about early aseptic loosening. Cruciate-retaining (CR) prostheses, using mini-keel implants, have yet to be reported and compared to posterior-stabilizing (PS) designs.

Methods

A retrospective, case-matched study of 91 consecutive TKAs (n = 46 CR; n = 45 PS prostheses), using modular mini-keel tibial componentry with a 45-mm drop down stem extension, was conducted. The Knee Society Score functional survey, radiographic analysis including alignment and periprosthetic radiolucency, TKA prosthesis longevity, and surgical complications were reported and compared between CR and PS groups.

Results

The Knee Society Score at 5-year follow-up averaged 81.67 ± 11.97 and 80.12 ± 14.16 in the CR and PS groups, respectively (p = 0.29). The femorotibial angle averaged 5.85° ± 2.62° and 5.85° ± 3.27° valgus in the CR and PS groups, respectively (p = 0.60). The average tibial component angle was 0.46° ± 1.6° and 0.61° ± 1.3° varus in the CR and PS groups, respectively (p = 0.30); posterior inclination averaged 2.28° ± 2.36° and 1.93° ± 2.72° in the CR and PS groups, respectively (p = 0.51). Radiolucency was noted in 17 zones of the CR group and in 9 zones of the PS group (p = 0.24). Three TKAs required further surgery: one locking plate fixation for a periprosthetic tibial fracture (PS group) and two revision TKAs (one CR infection and one PS fracture).

Conclusion

Modular mini-keel tibial components showed good reliability and results with both CR and PS prostheses in minimally invasive surgery TKA.

Up to seven years' follow-up of short cemented stems in complex primary total knee arthroplasty: A prospective study

BACKGROUND

Although primary total knee arthroplasty (TKA) shows good clinical, functional and radiological results, it can be complicated by certain conditions or pathologies. The main objective of this study was to evaluate the global performance of short cemented metaphyseal stem components in patients undergoing complex primary TKA.

METHODS

This is a single-surgeon prospective case series of 91 patients who underwent complex primary TKA requiring short stem fixation between January 2009 and October 2014. Knee Society Scores, physical examinations, and radiological assessments were performed pre- and postoperatively at six weeks, three months, six months, 12months, and annually thereafter.

RESULTS

There were 40 females (46 TKAs) and 40 males (45 TKAs) in the study cohort. The left knee accounted for 52.7% of the surgeries. The average body-mass index (BMI) was 31.8kg/m². Knee Society Scores obtained at the latest follow-up showed 96.4% and 95.5% good-to-excellent results respectively for the Knee and Function sub-scores. Radiological assessment showed that all Knee Society roentgenographic scores were below 10, without any evidence of impending or possible failure. Only one revision was required in this cohort for a patient suffering a deep chronic infection. At seven years, the Kaplan-Meier survivorship analysis revealed a 100% survivorship for aseptic loosening and a 98.9% survivorship for infection and revision of the components for any reason.

CONCLUSION

This study demonstrated that TKA with short cemented stems resulted in good functional, clinical, and radiological outcomes for up to seven years for patients requiring complex TKA.

Low Rates of Aseptic Tibial Loosening in Obese Patients With Use of High-Viscosity Cement and Standard Tibial Tray: 2-Year Minimum Follow-Up

BACKGROUND

Total knee arthroplasty is overall a very successful surgery, but complications do occur. These complications include aseptic loosening of the tibial component, and obese patients are among the highest risk group. High-viscosity cement (HVC) has been implicated as a possible cause for aseptic loosening of the tibial component. The purpose of this study was to evaluate the incidence of aseptic loosening of the tibial component in obese patients with the use of HVC and standard tibial tray.

METHODS

We identified 1366 obese patients (1851 knees) with a body mass index >35 kg/m² and 2-year minimum follow-up who underwent primary total knee arthroplasty using HVC and a symmetrical, grit-blasted, cobalt-chrome tibial component with 40-mm stem. Preoperative and postoperative range of motion, Knee Society (KS) scores, complications, and reoperations were evaluated. Specifically, we assessed the rate of tibial aseptic loosening.

RESULTS

At a mean 5.4 years follow-up, only 1 in 1851 knees had aseptic loosening of the tibial component for an incidence of 0.054%. There was a mean increase of 3.3 degrees of knee range of motion. KS pain level decreased by 38.6 points (50 point scale). KS clinical scores improved by 52.2, Knee Society functional scores improved by 19.5, University of California, Los Angeles, activity score improved by 0.9, and Oxford Knee Score by 15.7. All these improvements were statistically significant with P < .001.

CONCLUSION

Standard tibial components and HVC can be used in most patients, including the high-risk obese group, with low rates of tibial aseptic loosening.