Knee range of motion during the first two years after use of posterior cruciate-stabilizing or posterior cruciate-retaining total knee prostheses. A randomized clinical trial

Anterior cortical line of femur and tibia is more accurate than mid-shaft line to determine knee extension angle relative to sagittal mechanical axis during total knee arthroplasty

BACKGROUND

Accurate assessment of knee extension angle relative to sagittal mechanical axis (SMA) during TKA is usually obtained by computer navigation. Whether the lines along anterior cortex of distal femur and proximal tibia in short-knee imaging are accurate in determining knee extension angle has not been investigated.

METHODS

A prospective study was conducted on 106 patients (116 knees) who underwent primary TKA. After complete anesthetization, the leg was elevated 30° and short-knee lateral fluoroscopy was performed. The angles between the anterior cortical line (ACL), and between the mid-shaft line (MSL) of the femur and tibia, were measured. After surgical exposure and bony registration into OrthoPilot navigation system, the leg was elevated again and degree of knee extension was recorded. The angles determined using three methods were compared.

RESULTS

The mean extension angle observed by OrthoPilot (5.0° ± 6.8°, range -8°-25°) was not different from ACL method (5.3° ± 7.0°, range -8.1°-24.3°) (p = 0.811), but higher than MSL method (1.7° ± 7.1°, range -13.2°-18.1°) (p < 0.001). The mean absolute difference of ACL method from OrthoPilot was 0.2° ± 1.8° (range 0.0°-5.0°; 95%CI 0.0°-2.0°), and MSL method from OrthoPilot was 3.2° ± 2.6° (range 0.1°-8.2°; 95%CI 2.7°-3.7°). Measurement differences within 2° were found in 83.6% (97/116) and 37.9% (44/116) in the ACL and MSL method respectively (p < 0.001).

CONCLUSION

ACL of femur and tibia in a short-knee imaging is more accurate than MSL for determining knee extension angle relative to SMA. ACL can be assessed intraoperatively as the anterior cutting surface of distal femur after bone cut during TKA and the palpable anterior tibial crest. This ACL measurement in a pre- or postoperative radiograph provides the minimal detectable change of 3.5° and helpful in clinical research that requires high precision measurement.

Management of fixed flexion contracture in primary total knee arthroplasty: recent systematic review

INTRODUCTION

This study aimed to systematically review the literature and identify the surgical management strategy for fixed flexion contracture in primary total knee arthroplasty (TKA) surgery, pre-, intra-, and post-operatively. Secondary endpoints were etiologies and factors favoring flexion contracture.

MATERIALS AND METHODS

Searches were carried out in November 2023 in several databases (Pubmed, Scopus, Cochrane, and Google Scholar) using the following keywords: "flexion contracture AND TKA", "fixed flexion deformity AND TKA", "posterior capsular release AND TKA", "posterior capsulotomy in TKA", "distal femoral resection AND TKA". Study quality was assessed using the STROBE checklist and the Downs and Black score. Data concerning factors or strategies leading to the development or prevention of flexion contracture after TKA were extracted from the text, figures, and tables of the included references. The effect of each predictive factor on flexion contracture after TKA was recorded.

RESULTS

Thirty-one studies were identified to meet the inclusion and exclusion criteria. These studies described a variety of preoperative and intraoperative factors that contribute to the development or correction of postoperative flexion contracture. The only clearly identified predictor of postoperative flexion contracture was preoperative flexion contracture. Intraoperative steps described to correct flexion contracture were: soft-tissue balancing (in posterior and medial compartments), distal femoral resection, flexion of the femoral component, and posterior condylar resection. However, no study has investigated these factors in a global model.

DISCUSSION

This review identified various pre-, intra-, and post-operative factors predictive of post-operative flexion contracture. In practice, these factors are likely to interact, and it is therefore crucial to further investigate them in a comprehensive model to develop an algorithm for the management of flexion contracture.

LEVEL OF EVIDENCE

IV.

The effectiveness of cruciate-retaining versus posterior-stabilized designs on extensor mechanism function and knee function in patients after simultaneous bilateral total knee arthroplasty: A two-year retrospective follow-up study

INTRODUCTION

The importance of the posterior-cruciate ligament in knee functionality is known; however, the effect of preserving the posterior-cruciate ligament in total knee arthroplasty (TKA) on extensor mechanism function and knee function is not clear. We aimed to compare extensor mechanism function and knee function between patients operated with the cruciate-retaining and posterior-stabilized designs for simultaneous bilateral TKA.

HYPOTHESIS

Patients operated with the cruciate-retaining design would produce better outcomes than those operated with the posterior-stabilized design.

MATERIALS AND METHODS

A total of 104 patients were divided into two groups as the cruciate-retaining (n=52) and posterior-stabilized (n=52) groups. The groups were compared for extensor mechanism function (chair-rise test) and knee function (Hospital for Special Surgery [HSS] knee score). The follow-up points were six weeks, three months, six months, one year and two years.

RESULTS

No statistically significant effect on chair-rise performance of the group-by-time interaction (χ2 [5, n=104]=5.32, p=.37) or of group (χ2 [1, n=104]=1.69, p=.19). In the HSS knee score, the group-by-time interaction was statistically significant (F [5.510]=6.24, p<.001). A statistically significant difference of 7.4 points in favor of the posterior-stabilized group was found at six weeks (p=.002). No statistically significant differences were found between the groups at the other follow-up points.

DISCUSSION

The cruciate-retaining and posterior-stabilized designs have similar outcomes with regard to extensor mechanism function and knee function in the long-term period in patients who underwent simultaneous bilateral TKA. In the short-term period, the posterior-stabilized design shows better knee function than the cruciate-retaining design.

LEVEL OF EVIDENCE

III; a retrospective study.

The Early Clinical Outcomes Following Unrestricted Caliper Verified Kinematic Alignment Using a Medial Stabilized Design Total Knee Arthroplasty With a Cruciate Retaining Insert

Background

Although various total knee arthroplasty (TKA) implant designs are widely used, the ideal TKA design is yet to be agreed upon. Although the benefits of cruciate-retaining (CR) TKA and medial stabilized (MS) TKA have been reported in literature, the early clinical outcomes of an MS TKA with CR inserts have not been reported. This study aims to report on the patient-reported clinical and radiological outcomes of MS-TKA combined with a CR insert.

Methods

A prospective single-surgeon series evaluated the clinical- and patient-reported outcomes of 115 patients implanted with GMK Sphere CR. Patient outcomes were assessed with the Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Scores (KOOS), Forgotten Joint Score, and Visual Analogue Scale for Satisfaction. Radiological assessment for alignment along with active flexion and extension were also assessed.

Results

Improvement in all scores was observed between the preoperative and 1-year follow-up timepoints, with statistical significance seen for Oxford Knee Score as well as KOOS Symptoms, Pain, Sport, quality of life, and activities of daily living subscales. The mean active flexion between the preoperative and both postoperative timepoints at 6 months and 1 year was also statistically significant (P = .021 and P = .001).

Conclusions

MS-TKA with a CR insert can facilitate symptom relief and improve overall function of the knee after surgery. Both the patient and clinical outcomes were comparable to 1-year outcomes utilizing other MS-TKA designs and were superior to those at 1-year follow-up following implantation of CR-TKA. Most notability, the KOOS symptoms and sports score were higher for the MS-TKA with a CR insert than for an MS-TKA design.

The biomechanical and functional outcomes of autologous chondrocyte implantation for articular cartilage defects of the knee: A systematic review

PURPOSE

Autologous chondrocyte implantation (ACI) is primarily performed in active, young patients to treat knee pain and functional limitations resulting from articular cartilage injury. Nevertheless, the functional outcomes of ACI remain poorly understood. This systematic review aimed to evaluate the biomechanical and functional outcomes of ACI.

METHODS

Ovid MEDLINE, Embase, and Web of Science were systematically searched using the terms 'Knee OR Knee joint AND Autologous chondrocyte implantation OR ACI'. Inclusion and exclusion criteria were used to screen publications by title, abstract, and full text. Study quality and bias were assessed by two reviewers. Means and standard deviations of all collected variables were calculated and presented in the review.

PROSPERO ID

CRD42021238768.

RESULTS

Nineteen articles including 20 ACI cohorts were included. In general, the average range of motion (ROM) improved with clinical (>5°) and statistical significance (p < 0.05) postoperatively: 130.5 ± 14.8° to 136.1 ± 10.2°. Knee strength significantly improved within the first two postoperative years but remained poorer than control groups at final follow-up. No statistical differences were found between ACI and control groups in their ability to perform functional activities like the 6-minute walk test.

CONCLUSION

Knee range of motion generally improved following ACI. Although, some studies reported that knee strengths remained significantly poorer than healthy controls, particularly >2-years postoperatively, implying that longer-term strength training may benefit patients.However, the volume of research and current level of evidence remain low, thus further research is required to better understand the impact of ACI on knee function and guide future rehabilitative protocols.

Comparison of clinical outcomes among total knee arthroplasties using posterior-stabilized, cruciate-retaining, bi-cruciate substituting, bi-cruciate retaining designs: a systematic review and network meta-analysis

BACKGROUND

Despite the advent of innovative knee prosthesis design, a consistent first-option knee implant design in total knee arthroplasty (TKA) remained unsettled. This study aimed to compare the clinical effects among posterior-stabilized (PS), cruciate-retaining (CR), bi-cruciate substituting (BCS), and bi-cruciate retaining designs for primary TKA.

METHODS

Electronic databases were systematically searched to identify eligible randomized controlled trials (RCTs) and cohort studies from inception up to July 30, 2021. The primary outcomes were the range of knee motion (ROM), and the secondary outcomes were the patient-reported outcome measures (PROMs) and complication and revision rates. Confidence in evidence was assessed using Confidence in Network Meta-Analysis. The Bayesian network meta-analysis was performed for synthesis.

RESULTS

A total of 15 RCTs and 18 cohort studies involving 3520 knees were included. The heterogeneity and inconsistency were acceptable. There was a significant difference in ROM at the early follow-up when PS was compared with CR (mean difference [MD] = 3.17, 95% confidence interval [CI] 0.07, 7.18) and BCS was compared with CR (MD = 9.69, 95% CI 2.18, 17.51). But at the long-term follow-up, there was no significant difference in ROM in any one knee implant compared with the others. No significant increase was found in the PROMs and complication and revision rates at the final follow-up time.

CONCLUSIONS

At early follow-up after TKA, PS and BCS knee implants significantly outperform the CR knee implant in ROM. But in the long run, the available evidence suggests different knee prostheses could make no difference in clinical outcomes after TKA with extended follow-up.

Cruciate-Retaining Total Knee Arthroplasty: Current Concepts Review

Posterior cruciate-retaining (CR) total knee arthroplasty for osteoarthritis of the knee is a popular implant choice. At present, there is no consensus on whether sacrifice or retention of the posterior cruciate ligament (PCL) offers superior outcomes. This review explores the current literature available on CR total knee arthroplasty (TKA). PubMed was searched by keyword to find relevant articles for inclusion. Additional sources came from article references and joint registry reports. CR design knees have distinct kinematic gait patterns from posterior-stabilizing (PS) knees and exhibit paradoxical anterior femoral movement with less femoral rollback. While CR implants offer less flexion than PS designs, the difference is not clinically detectable as clinical scores are similar in the short and long term. CR implants have better long-term survival compared to PS knees, likely due to lower risk of aseptic loosening. CR total knee arthroplasties also have shorter operating times and lower risk of peri-prosthetic fractures. Because the CR implant is unconstrained, there may be an increased risk of instability compared to PS designs, but the literature is mixed. Overall, the current literature supports the continued use of CR TKAs due to their lower risk of complications, durability, and demonstrated equivalence in function to posterior-substituting models.

Polyethylene Components in Primary Total Knee Arthroplasty: A Comprehensive Overview of Fixed Bearing Design Options

The articular design of a polyethylene insert influences the kinematics and overall function of a total knee arthroplasty (TKA). Standard symmetric posterior-stabilized and cruciate-retaining polyethylene designs have a long track record of high patient satisfaction and longevity in TKA. However, the number and variety of polyethylene inserts and articulations have continued to evolve in an attempt to better replicate native knee kinematics or provide additional constraint. Ultracongruent polyethylene designs have been touted as increasing stability while maintaining the benefits of cruciate-retaining knees. Medial pivot and lateral/dual pivot polyethylene designs were introduced to mimic more normal knee kinematics with regard to femoral rollback. Further, with increasing recognition of knee instability as a cause for persistent symptoms and revision TKA, the utilization of midlevel constraint polyethylene inserts has been increasing, with multiple implant companies offering an insert design with increased constraint for use with a primary femoral component. In this rapidly evolving arena in with a myriad of options available, surgeons should be knowledgeable about the design concepts and their applicable uses for specific patient scenarios. Future research is needed to better understand whether a particular type or design of polyethylene insert and articulation leads to improved patient reported outcomes, improved replication of knee kinematics, and long-term durable implant survivorship.

Comparison of Single-Radius with Multiple-Radius Femur in Total Knee Arthroplasty: A Meta-Analysis of Prospective Randomized Controlled Trials

BACKGROUND

Whether there was clinical superiority for the single-radius prosthesis over the multi-radius prothesis in total knee arthroplasty (TKA) still remains to be clarified. We updated a meta-analysis including prospective randomized controlled trials (RCTs) to compare the clinical prognosis of patients receiving single-radius TKA (SR-TKA) or multi-radius TKA (MR-TKA).

METHODS

We searched the databases of PubMed, Web of Science, EMBASE, Cochrane Library, MEDLINE for eligible RCTs. Two reviewers evaluated the study quality according to the Risk of Bias tool of the Cochrane Library and extracted the data in studies individually. The extracted data included the baseline data and clinical outcome. The baseline data include the author's name, country, and year of included studies, the name of knee prosthesis used in studies, sample size, follow-up time, and BMI of patients. The clinical data comprised primary indicators including postoperative knee range of motion (ROM), sit-to-stand rest, severe postoperative scorings, such as visual analog scale (VAS), American Knee Society knee score (AKS), Oxford knee scoring (OKS), and SF-36 Quality of Life Scale, as well as various secondary indicators of complications including anterior knee pain, postoperative infection, aseptic prosthesis loosening, and prosthesis revision. The data analysis was performed using Review Manager 5.3 software and STATA 12.0. The sensitivity analysis was performed using STATA 12.0.

RESULTS

A total of 13 RCTs, along with 1720 patients and 1726 knees, were finally included in our present meta-analysis. We found that patients in SR-TKA group performed better in the sit-to-stand test (OR = 1.89, 95% CI: 1.05-3.41, p = 0.03) and satisfaction evaluation (OR = 3.27, 95% CI: 1.42-7.53, p = 0.005), which were only evaluated in two included RCTs. While no significant difference was found between SR-TKA and MR-TKA groups in terms of postoperative ROM, VAS scoring, AKS scoring, SF-36 scoring, OKS scoring, and various complications including anterior knee pain, postoperative infection, aseptic prosthesis loosening, and prosthesis revision.

CONCLUSION

In conclusion, our present meta-analysis indicated that SR implants were noninferior to MR implants in TKA, and SR implants could be an alternative choice over MR implants, since patients after SR-TKA felt more satisfied and performed better in the sit-to-stand test, with no significant difference in complications between SR-TKA and MR-TKA groups. While more relevant clinical trials with long-term follow-up time and specific tests evaluating the function of knee extension mechanism should be carried out to further investigate the clinical performance of SR implants.

No Benefit to Sensor-guided Balancing Compared With Freehand Balancing in TKA: A Randomized Controlled Trial

BACKGROUND

Soft tissue balancing in TKA has traditionally relied on surgeons' subjective tactile feedback. Although sensor-guided balancing devices have been proposed to provide more objective feedback, it is unclear whether their use improves patient outcomes.

QUESTIONS/PURPOSES

We conducted a randomized controlled trial (RCT) comparing freehand balancing with the use of a sensor-guided balancing device and evaluated (1) knee ROM, (2) patient-reported outcome measures (PROMs) (SF-12, WOMAC, and Knee Society Functional Scores [KSFS]), and (3) various surgical and hospital parameters (such as operative time, length of stay [LOS], and surgical complications) at a minimum of 2 years of follow-up.

METHODS

A total of 152 patients scheduled for primary TKA were recruited and provided informed consent to participate in this this study. Of these, 22 patients were excluded preoperatively, intraoperatively, or postoperatively due to patient request, surgery cancellation, anatomical exclusion criteria determined during surgery, technical issues with the sensor device, or loss to follow-up. After the minimum 2-year follow-up was accounted for, there were 63 sensor-guided and 67 freehand patients, for a total of 130 patients undergoing primary TKA for osteoarthritis. The procedures were performed by one of three fellowship-trained arthroplasty surgeons (RPS, HJC, JAG) and were randomized to either soft tissue balancing via a freehand technique or with a sensor-guided balancing device at one institution from December 2017 to December 2018. There was no difference in the mean age (72 ± 8 years versus 70 ± 9 years, mean difference 2; p = 0.11), BMI (30 ± 6 kg/m 2 versus 29 ± 6 kg/m 2 , mean difference 1; p = 0.83), gender (79% women versus 70% women; p = 0.22), and American Society of Anesthesiology score (2 ± 1 versus 2 ± 1, mean difference 0; p = 0.92) between the sensor-guided and freehand groups, respectively. For both groups, soft tissue balancing was performed after all bony cuts were completed and trial components inserted, with the primary difference in technique being the ability to quantify the intercompartmental balance using the trial tibial insert embedded with a wireless sensor in the sensor-guided cohort. Implant manufacturers were not standardized. Primary outcomes were knee ROM and PROMs at 3 months, 1 year, and 2 years. Secondary outcomes included pain level evaluated by the VAS, opioid consumption, inpatient physical therapy performance, LOS, discharge disposition, surgical complications, and reoperations.

RESULTS

There was no difference in the mean knee ROM at 3 months, 1 year, and 2 years postoperatively between the sensor-guided cohort (113° ± 11°, 119° ± 13°, and 116° ± 12°, respectively) and the freehand cohort (116° ± 13° [p = 0.36], 117° ± 13° [p = 0.41], and 117° ± 12° [p = 0.87], respectively). There was no difference in SF-12 physical, SF-12 mental, WOMAC pain, WOMAC stiffness, WOMAC function, and KSFS scores between the cohorts at 3 months, 1 year, and 2 years postoperatively. The mean operative time in the sensor-guided cohort was longer than that in the freehand cohort (107 ± 0.02 versus 84 ± 0.04 minutes, mean difference = 23 minutes; p = 0.008), but there were no differences in LOS, physical therapy performance, VAS pain scores, opioid consumption, discharge disposition, surgical complications, or percentages of patients in each group who underwent reoperation.

CONCLUSION

This RCT demonstrated that at 2 years postoperatively, the use of a sensor-balancing device for soft tissue balancing in TKA did not confer any additional benefit in terms of knee ROM, PROMs, and clinical outcomes. Given the significantly increased operative time and costs associated with the use of a sensor-balancing device, we recommend against its routine use in clinical practice by experienced surgeons.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Comparative Analysis of Contemporary Fixed Tibial Inserts: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

Background

Multiple options are available for the tibial insert in total knee arthroplasty (TKA). A systematic review (SR) and network meta-analysis (NMA) to compare available randomized controlled trials (RCTs) could assist with decision making. We aim to show that designs with increased conformity may improve function and satisfaction without an increase in complications though posterior stabilized (PS) inserts will likely have more flexion.

Methods

A search of MEDLINE, EMBASE, and the Cochrane Library was performed. Studies were limited to RCTs evaluating cruciate retaining (CR), PS, anterior stabilized (AS), medial pivot (MP), bicruciate retaining (BR), and bicruciate stabilizing (BCS) inserts. Mean differences (MD) were used for patient reported outcome measures (PROMs) and odds ratios (OR) for reoperation rates and MUA. A systematic review was performed for satisfaction.

Results

27 trials were identified. The NMA showed no difference from a statistical or clinical standpoint for PROMs evaluated. There was a statistical difference for increased flexion for PS knees (3 degrees p 0.04). There were no differences in the MUA or reoperation rates. There was insufficient information to determine if a specific insert improved satisfaction.

Discussion

The results of this NMA show no statistical or clinical difference in PROMs. There was higher flexion for PS knees though the amount was not clinically significant. There was insufficient data for conclusions on patient satisfaction. Therefore, the surgeon should evaluate the clinical situation to determine the best insert rather than choose and insert based on functional scores, patient satisfaction, or complication rates.

Biomechanics and Outcomes of Modern Tibial Polyethylene Inserts

PURPOSE OF REVIEW

There have been many attempts to use variations in tibial polyethylene design to better recreate normal knee kinematics in the total knee arthroplasty. The goal of this review is to provide an overview of the various types of tibial inserts that exist and review the theoretical mechanics versus what was demonstrated in vivo.

RECENT FINDINGS

Many polyethylene inserts have been attempted to re-create normal knee kinematics, but none have been able to successfully do so. Previously the only two types of inserts were posterior stabilized (PS) and cruciate retaining (CR) polyethylene inserts. Both of these have shown excellent long-term survival but neither has demonstrated native kinematics. Initially, it was thought that retention of the posterior cruciate ligament (PCL) would allow for more native kinematics, but fluoroscopic evidence has shown that the PCL alone cannot accomplish this. Newer inserts try to restore femoral roll back and the screw home mechanism. The bicruciate retaining total knee inserts are having the most "normal" kinematics, suggesting the importance of both the ACL and PCL in knee biomechanics. Modern polyethylene inserts show favorable short-term data with bicruciate retaining inserts having the best kinematics; however, long-term studies are still needed to determine if survivorship and patient outcomes remain favorable.

Incidence and effectiveness of manipulation under anaesthesia for stiffness following primary total knee arthroplasty

Background

There are various modalities of cor- rection of stiffness following total knee arthro-plasty. Manipulation under anaesthesia (MUA) is generally indicated for people who fail to achieve their pre operative range of motion at 12 weeks. The purpose of this study was to determine: (1) the effect of MUA on Flexion arc (2) the influence of timing of MUA from index procedure and of diabetes mellitus on final flexion achieved.

Methods

We retrospectively evaluated patients who underwent manipulation following total knee arthroplasty at our institution between January 2016 to December 2018. For the purpose of analysis, we have divided the patients into two groups. Those who underwent manipulation within 12 weeks and later than 12 weeks. We have also compared the effect of MUA between diabetic and non-diabetic patients. All were operated with posterior stabilised (PS) prosthesis by a single senior arthroplasty surgeon. The final flexion achieved during their last clinical follow-up were recorded and compared with the pre MUA flexion.

Results

The incidence of MUA after TKA at our institute during this period is about 1.14 %. There was a significant statistical difference between the pre and post manipulation flexion, with p value <0.01. There was no significant statistical difference between those who were manipulated before 12 weeks and after 12 weeks in improving the Flexion of the operated knees. We have found that both the diabetic and non diabetic group had comparable flexion after the manipulation in our study.

Conclusion

Manipulation after anaesthesia is a safe first intervention to improve post operative stiffness and gain additional range of motion following TKA in patients who develop stiffness. It can be done even after 12 weeks of surgery with reasonably good gain in range of motion.

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 of Cruciate-Sacrificing vs Posterior-Stabilized Total Knee Replacement Using a Contemporary Total Knee System

BACKGROUND

The use of highly conforming polyethylene tibial inserts in cruciate-retaining total knee arthroplasty (TKA) often requires posterior cruciate ligament (PCL) release/sacrifice for balancing (CS TKA). The CS TKA relies on the posterior capsule, collateral ligaments, and articular conformity without a cam or post to achieve stability. Using prospectively collected data we compared clinical outcomes of CS TKA to posterior-stabilized (PS) TKA utilizing a contemporary TKA system.

METHODS

Sixty-nine consecutive CS TKAs were compared to 45 consecutive PS TKAs at 2-year minimum follow-up. CS knees were balanced with the PCL released. Preoperative/postoperative range of motion (ROM), Knee Society Scores (KSS), stair function, and squatting ROM were analyzed.

RESULTS

At minimum 2-year follow up, CS and PS TKA demonstrated significant improvement in ROM (P < .001), KSS (Pain, P < .001; Function, P < .001), and KSS stair function (P < .001), with no revisions. There was no difference in preoperative to postoperative improvements for passive knee ROM (10° (0°-20°) vs 13° (5°-25°); P = .16), KSS Pain (34 (21-42) vs 38 (24-46); P = .22), KSS Function (35 (30-50) vs 35 (18-50); P = .34), and KSS stair function (10 (10-20) vs 10 (0-20); P = .37) for CS and PS TKA, respectively. CS TKA had higher squatting ROM (P = .02) at minimum 2-year follow-up compared to PS TKA.

CONCLUSION

Both PS and CS TKA provided significant improvement in clinical outcomes, with no differences in passive ROM, KSS, or stair function postoperatively. Our data support that with proper articular conformity and balancing, cruciate-retaining TKA in a PCL-deficient knee (CS TKA) is appropriate. This may be design specific and further prospective randomized studies are needed to corroborate these findings.

Is high flexion total knee arthroplasty a rewarding procedure? An updated meta-analysis of prospective randomized controlled trials

INTRODUCTION

The aim of this study is to provide an updated meta-analysis comparing the benefits and clinical outcomes between high flexion (HF)-TKA and standard (S)-TKA.

MATERIALS AND METHODS

A detailed database analysis was carried out using Web of Science, PubMed, EMBASE, Cochrane Library, MEDLINE and Clinicaltrial.gov, to identify eligible studies. The meta-analysis and sensitivity analysis were performed using Review Manager 5.3 software and STATA 12.0.

RESULTS

Twenty-two randomized control trials (RCTs), including 2841 patients and 4268 knees, were eligible for the meta-analysis. The pooled results of subgroup analysis reveal that there was significant difference between HF-TKA and S-TKA in each subgroup in terms of postoperative ROM, with a higher degree of knee flexion for HF-TKA than S-TKA. However, no statistical difference was identified between HF-TKA and S-TKA in other clinical outcomes including various functional scores and complications.

CONCLUSIONS

On the basis of this meta-analysis, we can recommended HF-TKA as an alternative choice to S-TKA for patients requiring higher knee flexion in their daily activities.

No Difference in Recovery of Patient-Reported Outcome and Range of Motion between Cruciate Retaining and Posterior Stabilized Total Knee Arthroplasty: A Double-Blind Randomized Controlled Trial

Both from the perspective of the individual and from a socioeconomic point of view (e.g., return to work), it is important to have an insight into the potential differences in recovery between posterior cruciate ligament retaining (PCR) and posterior stabilized (PS) total knee arthroplasty (TKA) implants. The primary aim of this study was to compare the speed of recovery of patient-reported outcome between patients with a PCR and PS TKA during the first postoperative year. The secondary aim was to compare the effect on range of motion (ROM). In a randomized, double-blind, controlled, single-center trial, 120 adults diagnosed with osteoarthritis of the knee were randomized into either the PCR or PS group. Primary outcome was speed of recovery of patient-reported pain and function, measured with the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), with a follow-up of 1 year. Main secondary outcome measure was ROM. A generalized estimating equations (GEE) analysis was used to assess whether there was a difference over time between groups ("p-value for interaction"). Between 2008 and 2011, 59 participants received a PCR TKA (mean age, 70.3 years [SD = 7.7]; mean body mass index [BMI], 30.5 kg/m² [SD = 5.4]) and 55 participants a PS TKA (mean age, 73.5 years [SD = 7.0]; mean BMI, 29.2 kg/m² [SD = 4.4]). Six patients (two PCR and four PS) were excluded because of early drop-out, so 114 patients (95%) were available for analysis. In between group difference for total WOMAC score was -1.3 (95% confidence interval [CI]: -5.6 to 3.1); p-value for interaction was 0.698. For ROM, in between group difference was 1.1 (95% CI: -2.6 to 4.7); p-value for interaction was 0.379. These results demonstrated that there are no differences in speed of recovery of WOMAC or ROM during the first postoperative year after PCR or PS TKA.

An Assessment of Randomized Controlled Trial Quality in The Journal of Bone & Joint Surgery: Update from 2001 to 2013

BACKGROUND

The quality of reporting of randomized controlled trials (RCTs) published in The Journal of Bone & Joint Surgery (JBJS) from 1988 to 2000 was previously analyzed. The purpose of this current study was to analyze the quality of reporting of RCTs published in JBJS from 2001 to 2013 to identify trends over time and potential areas of improvement for future clinical trials.

METHODS

A manual search of the JBJS database identified RCTs published between January 2001 and December 2013. Quality assessments, using the Detsky quality-of-reporting index (Detsky score), a modified Cochrane risk-of-bias tool, and abstraction of relevant data identifying predictors of quality, were conducted.

RESULTS

A total of 5,780 publications were identified in JBJS from 2001 to 2013, with 285 RCTs (4.9%), representing an increase from the prior 13-year period. The overall mean transformed Detsky score (and standard error) increased significantly (p < 0.001) from 68.1% ± 1.67% to 76.24% ± 0.72%. The percentage of multicenter RCTs decreased from 67% to 31%. The percentage of positive trials also decreased from 80% to 50.5%, as did the mean sample size (212 to 166). Regression analysis indicated that trials with an epidemiologist as the first author and nonsurgical trials were significantly associated (p = 0.001) with a higher overall trial quality score. The categories of the lowest mean methodology scores were randomization and concealment, eligibility criteria, and reasons for patient exclusion, as identified with the Detsky score, and patient and assessor blinding, as identified with the risk-of-bias assessment.

CONCLUSIONS

The quantity and quality of published RCTs in JBJS have increased in the 2001 to 2013 time period compared with the previous time period. Although these improvements are encouraging, trends to smaller, single-center trials were also observed. To efficiently determine the efficacy of orthopaedic treatments and limit bias, high-quality randomized trials of appropriate sample size and rigorous design are needed.

J-curve design total knee arthroplasty: the posterior stabilized shows wider medial pivot compared to the cruciate retaining during chair raising

PURPOSE

Which total knee arthroplasty (TKA) design represents the better solution to restore a correct knee biomechanics is still debated. The aim of this study was to compare posterior stabilized (PS) and cruciate retaining (CR) version of the same TKA design (femoral component with an anatomic sagittal radius-J-curve design) by the use of dynamic Roentgen stereophotogrammetric analysis (RSA). The hypothesis was that the two models influence differently in vivo knee kinematic.

METHODS

A cohort of 16 randomly selected patients was evaluated 9 months after surgery: Zimmer PERSONA® was implanted, eight with CR design and eight with PS design. The kinematic evaluations were performed using a Dynamic RSA (BI-STAND DRX 2) developed in our Institute, during the execution of the sit-to-stand motor task. The motion parameters were obtained using the Grood and Suntay decomposition and the low-point kinematics methods.

RESULTS

PS TKA lateral femoral compartment had a wider anterior translation (17 ± 2 mm) than the medial one (11 ± 2 mm), while the two compartments of CR TKA showed a similar anterior translation (medial: 9 ± 2 mm/lateral: 11 ± 2 mm). T test for comparison between CR and PS TKA of antero-posterior translation showed a statistically significant difference (p < 0.05) in the flexion range between 15° and 40°. The CR prosthesis did not anteriorly translate during flexion. The PS design translated anteriorly showing a roll-forward mechanism during extension from 80° to 18° of flexion and a posterior translation from 18° to 0°. The same significant differences (p < 0.05) between the PS and CR groups were found comparing the low-point positions of the femoral condyles in the range of flexion between 25° and 40° for the medial compartment and between 15° and 25° for the lateral compartment.

CONCLUSIONS

Dynamic RSA was able to investigate for the first time in vivo the kinematic behaviour of PS and CR version of the same TKA J-curve design. PS type showed a medial pivot during sit-to-stand motion task, while the CR type showed a cylindrical movement. Further studies are needed to evaluate the impact of different TKA designs on clinical results.

LEVEL OF EVIDENCE

IV.

Risk factors for manipulation under anaesthesia after total knee arthroplasty

Aims

Postoperative range of movement (ROM) is an important measure of successful and satisfying total knee arthroplasty (TKA). Reduced postoperative ROM may be evident in up to 20% of all TKAs and negatively affects satisfaction. To improve ROM, manipulation under anaesthesia (MUA) may be performed. Historically, a limited ROM preoperatively was used as the key harbinger of the postoperative ROM. However, comorbidities may also be useful in predicting postoperative stiffness. The goal was to assess preoperative comorbidities in patients undergoing TKA relative to incidence of postoperative MUA. The hope is to forecast those who may be at increased risk and determine if MUA is an effective form of treatment.

Methods

Prospectively collected data of TKAs performed at our institution’s two hospitals from August 2014 to August 2018 were evaluated for incidence of MUA. Comorbid conditions, risk factors, implant component design and fixation method (cemented vs cementless), and discharge disposition were analyzed. Overall, 3,556 TKAs met the inclusion criteria. Of those, 164 underwent MUA.

Results

Patients with increased age and body mass index (BMI) had decreased likelihood of MUA. For every one-year increase in age, the likelihood of MUA decreased by 4%. Similarly, for every one-unit increase in BMI the likelihood of MUA decreased by 6%. There were no differences in incidence of MUA between component type/design or fixation method. Current or former smokers were more likely to have no MUA. Surprisingly, patients discharged to home health service or skilled nursing facility were approximately 40% and 70% less likely than those discharged home with outpatient therapy to be in the MUA group. MUA was effective, with a mean increased ROM of 32.81° (SD 19.85°; -15° to 90°).

Conclusion

Younger, thinner patients had highest incidence of MUA. Effect of discharge disposition on rate of MUA was an important finding and may influence surgeons’ decisions. Interestingly, use of cement and component design (constraint) did not impact incidence of MUA. Level of Evidence II: Prospective cohort study. Cite this article: Bone Joint J 2020;102-B(6 Supple A):66–72.

Differences in outcome after cruciate retaining and posterior stabilized total knee arthroplasty

BACKGROUND

Both cruciate retaining (CR) and posterior stabilized (PS) implants are commonly used for primary total knee arthroplasty. There is evidence to support improved range of motion in PS knee replacements, but there is no evidence showing functional superiority. The aim of this study was to compare functional outcomes between CR and PS knee replacements.

PATIENT AND METHODS

Prospectively collected regional joint registry data were used to compare preoperative and postoperative one, 5- and 10-year Oxford and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in 1287 primary total knee replacements. Differences in functional scores between CR and PS knees were calculated.

RESULTS

The PS group had better functional scores than the CR group at baseline (mean Oxford score 15.59 vs. 14.52 ( p = 0.026) and mean WOMAC score 59.51 vs. 62.35 ( p = 0.012)), at 1 year postoperatively (mean Oxford score 37.94 vs. 36.63 ( p = 0.015) and mean WOMAC score 16.20 vs. 19.73 ( p = 0.001)) with a similar trend at 5 years postoperatively (mean Oxford score 39.66 vs. 38.50 ( p = 0.054) and mean WOMAC score 16.89 vs. 18.83 ( p = 0.131)). There was no difference in the overall functional improvement between the PS and CR groups at 1, 5, or 10 years. WOMAC subcomponent scores showed greater improvement in stiffness; 3.76 versus 3.36 ( p = 0.012) in PS knees at 1 year postoperatively. No significant differences were observed at 5 or 10 years.

CONCLUSIONS

PS knee replacements showed greater improvement in stiffness at 1 year postoperatively. There was no difference observed at 5 or 10 years postoperatively. PS knees had better functional outcomes at 1 year with a similar trend at 5 years postoperatively.

LEVEL OF EVIDENCE

III.

Comparison of Posterior Cruciate-Retaining and High-Flexion Cruciate-Retaining Total Knee Arthroplasty Design

BACKGROUND

High-flexion prostheses have been developed to achieve deep flexion after total knee arthroplasty. The purpose of this study is to compare standard NexGen (CR, cruciate-retaining) and high-flexion NexGen (CR-flex) total knee prostheses in terms of range of motion, clinical and radiologic outcomes, rates of complications, and survivorship in long-term follow-up.

METHODS

From January 2000 to December 2008, 423 consecutive knees underwent total knee arthroplasty using standard CR or CR-flex prostheses. Fifty-three patients were lost to follow-up or declined to participate and 54 died, leaving 290 knees. The minimum duration of follow-up was 8 years (mean 10.1 years). Physical examination and knee scoring of patients were assessed preoperatively, at 6 months and 1 year after surgery, and annually thereafter. Supine anteroposterior and lateral radiographs and standing anteroposterior hip-to-ankle radiographs were obtained preoperatively and at each follow-up.

RESULTS

Mean postoperative range of motions in the standard CR group and the CR-flex group were similar, showing no significant difference between the 2 groups (P = .853). At the time of the final follow-up, mean total Hospital for Special Surgery scores were similar between the 2 groups (P = .118). Mean Knee Society pain (P = .325) and function scores (P = .659) were also comparable between the 2 groups. Western Ontario and McMaster Universities Osteoarthritis Index score showed no intergroup difference either (P = .586). The mean hip-knee-ankle angle at the final follow-up was approximately the same (P = .940). Mean coronal angles of femoral and tibial component at final follow-up were also similar (P = .211 and P = .764, respectively). The prevalence of the radiolucent line was 0.6% in the standard CR group and 0.9% in the CR-flex group. Estimated survival rate according to Kaplan-Meier survival analysis was 97.2% in the standard CR group and 95.6% in the CR-flex group at mean follow-up of 10.1 years.

CONCLUSION

This study suggests that excellent clinical and radiographic outcomes could be achieved with both standard and high-flexion CR total knee designs. High-flexion CR prosthesis did not show any advantages over the standard design.

Total Knee Arthroplasty Kinematics

Knee kinematics is an analysis of motion pattern that is utilized to assess a comparative, biomechanical performance of healthy nonimplanted knees, injured nonimplanted knees, and various prosthetic knee designs. Unfortunately, a consensus between implanted knee kinematics and outcomes has not been reached. One might hypothesize that the kinematic variances between the nonimplanted and implanted knee might play a role in patient dissatisfaction following TKA. There is a wide range of TKA designs available today. With such variety, it is important for surgeons and engineers to understand the various geometries and kinematic profiles of available prostheses. The purpose of this review is to provide readers with the pertinent information related to TKA kinematics.

Comparison of Anterior-Stabilized and Posterior-Stabilized Total Knee Arthroplasty in the Same Patients: A Prospective Randomized Study

BACKGROUND

A highly conforming, anterior-stabilized (AS) insert is designed to provide anteroposterior (AP) stability of the posterior-stabilized (PS) insert without a post. The purpose of this study was to compare the static and dynamic stability and function of AS and PS total knee arthroplasty (TKA) in the same patients.

METHODS

A prospective, randomized controlled trial was performed in 45 patients scheduled to undergo same-day bilateral TKA. One knee was randomly assigned to receive an AS TKA, and the other knee was scheduled for a PS TKA from the same knee system. At 2 years postoperatively, the static AP stability was compared using anterior and posterior drawer stress radiographs at 90° knee flexion. Dynamic AP stability was evaluated using one-leg standing lateral fluoroscopic images throughout the range of motion. Knee function was compared using the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index score.

RESULTS

At 2 years postoperatively, there was a significant difference in knee AP laxity at 90° of flexion between the two groups (7.6 ± 3.9 mm in the AS group vs 2.2 ± 2.3 in the PS group, P < .001). However, there were no differences in dynamic AP stability under one-leg standing fluoroscopic lateral images at 30°, 60°, and 90° knee flexion (P = .732, P = .764, and P = .679, respectively). The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index scores were not significantly different between the two groups (P = .641 and P = .582, respectively).

CONCLUSION

Despite the fact that the AS TKA group showed significantly more static posterior displacement than the PS TKA group at 90° of knee flexion, both the AS and PS TKA groups showed similar dynamic stability under weight-bearing conditions and knee function at 2 years postoperatively.

Mediolateral coronal laxity does not correlate with knee range of motion after total knee arthroplasty

INTRODUCTION

It remains controversial whether coronal laxity after total knee arthroplasty (TKA) is a critical factor in determining clinical outcomes such as knee range of motion (ROM). The purpose of this study was to evaluate the correlation between postoperative ROM and coronal laxity, which was defined as the angular motion from the neutral, unloaded position to the loaded position, in patients with medial knee osteoarthritis undergoing TKA.

MATERIALS AND METHODS

Preoperative and 1-year postoperative coronal laxity were assessed using radiographs by applying a force of 150 N with an arthrometer. A consecutive series of 204 knees was examined. A knee was defined as clinically "balanced" when the difference between medial and lateral laxity was 3° or less. Active ROM was measured using a goniometer. Values were expressed as median values.

RESULTS

The ROM was 105° preoperatively and 110° postoperatively, with the correlation being weak (r = 0.372, p < 0.001) between the periods. The total laxity also revealed a weak correlation (r = 0.270, p < 0.001) between the periods. Preoperative laxity was significantly larger (4° vs. 3°) on the medial side (p < 0.001) and postoperative laxity was larger (4° vs. 3°) laterally (p = 0.001). There was no significant correlation between postoperative ROM and laxity pre- and postoperatively. Additionally, there were no differences in ROM between the balanced and unbalanced groups in the pre- and postoperative periods.

CONCLUSIONS

This study indicated that mediolateral coronal laxity in patients with an osteoarthritic knee did not correlate with knee ROM after TKA when 3°-4° of laxity in the medial and lateral orientations was maintained.

Posterior-stabilized versus cruciate-retained implants for total knee arthroplasty: a meta-analysis of clinical trials

AIM

A meta-analysis comparing the outcomes of patients undergoing cruciate retaining (CR) versus posterior stabilized (PS) in primary total knee arthroplasty was performed. The outcomes of interest were the Knee Society Rating System, clinical (KSCS) and functional (KSFS) subscales, joint range of motion (ROM), surgical duration and further complications (anterior knee pain, instability and revision rate).

MATERIALS AND METHODS

The search was conducted in July 2018, accessing the following databases: Cochrane Systematic Reviews, Scopus, PubMed, EMBASE, CINAHL, AMED and Google Scholar. We included only clinical trials level of evidence I and II. During the statistical analysis, we excluded all the studies that affect negatively the I² test, in order to achieve more reliable results. For the methodological quality assessment we referred to the PEDro score. The risk of publication's bias was evaluated by the funnel plots across all the comparisons.

RESULTS

The PEDro score reported a good methodological quality assessment. The funnel plot detected a very low risk of publication's bias. We included in this study 36 articles, counting a total of 4052 patients and 4884 procedures. The mean follow-up term for both groups was 3.39 years. The ROM resulted in an overall estimate effect of 2.18° in favor of the PS group. The overall WOMAC showed a result in favor of the PS group. The overall estimate effect of the KSCS was 0.02% higher in the CR group. The KSFS showed an overall estimate effect of 2.09% in favor of the PS group. Concerning the surgical duration, the estimate effect resulted in 6.87 min shorter in the CR group. No differences were reported across the two groups regarding anterior knee pain, knee joint instability or revision rate.

CONCLUSION

Both the prosthetic implants provided to be a safety and feasible solution to treat end-stage knee joint degeneration. The PS implants reported improvements in the knee range of motion and a prolongation of the surgical time. No clinically relevant dissimilarities concerning the analyzed scores were evidenced. No statistically significant relevant differences in complications were detected.

Cruciate-Retaining vs Posterior-Stabilized Primary Total Arthroplasty. Clinical Outcome Comparison With a Minimum Follow-Up of 10 Years

BACKGROUND

Controversy continues regarding whether the posterior cruciate ligament should be retained or removed during total knee arthroplasty (TKA) procedure. The objective was to compare the clinical outcomes with a minimum follow-up of 10 years between patients who received contemporary cruciate-retaining or posterior-stabilized primary TKA.

METHODS

Case-control study of 268 patients who underwent cruciate-retaining TKA vs 211 to posterior-stabilized design, with the same arthroplasty system, and a minimum follow-up of 10 years. Clinical assessment was performed by Knee Society scores, Western Ontario and MacMasters Universities and Short-Form 12 questionnaires, range of motion, and patient satisfaction.

RESULTS

Successful outcomes were found for both designs. No significant differences in functional scores, range of motion, patient-related scores, or patient satisfaction. Between the 5-year and last postoperative follow-up, there were a significant decrease of all clinical scores in both groups. In addition, complication rate and implant survival were similar between groups.

CONCLUSION

The superiority of one design over the other was not found. Both designs can be used expecting long-term successful outcomes and high survival. The choice of the design depended on the status of the posterior cruciate ligament and surgeon preference.

Factors affecting the incidence and management of fixed flexion deformity in total knee arthroplasty: A systematic review

PURPOSE

This study aimed to systematically review the literature and identify factors which would contribute to the intraoperative correction of FFD to frame a potential surgical algorithm or predictive model to guide intraoperative decision-making.

METHODS

Electronic searches of six databases were undertaken in April 2016 according to the PRISMA guidelines, and the reference lists of studies searched. Quality of studies was assessed using the STROBE checklist, and the Downs and Black Scores.

RESULTS

Twenty-five studies investigating 10, 679 knees were found to satisfy the inclusion and exclusion criteria. These studies described a variety of pre-operative and intra-operative factors which contribute to the development or correction of post-operative FFD. The only patient predictor of post-operative FFD was pre-operative FFD. The intra-operative steps described to correct FFD were: distal femoral resection, soft-tissue balancing (in the posterior and medial compartments), sagittal component flexion and posterior condylar offset. However, no studies investigated these in an integrated model.

CONCLUSION

This review has identified various pre-, intra- and post-operative factors predictive of post-operative FFD. In practice, these factors are likely to interact, and therefore further investigation in an integrated model is crucial to developing a statistically sound and reliable intraoperative algorithm for surgeons to follow when correcting fixed flexion deformity.

A functional comparison of medial pivot and condylar knee designs based on patient outcomes and parameters of gait

Aims

The outcome of total knee arthroplasty (TKA) is not always satisfactory. The purpose of this study was to identify satisfaction and biomechanical features characterising the gait of patients who had undergone TKA with either an anatomical single radius design or a medial pivot design. We hypothesised that the latter would provide superior function.

Patients and Methods

This is a study of a subset of patients recruited into a prospective randomised study of a single radius design versus a medial pivot design, with a minimum follow-up of one year. Outcome measurements included clinical scores (Knee Society Score (KSS) and Oxford Knee Score (OKS)) and gait analysis using an instrumented treadmill.

Results

There was no statistically significant difference between the two groups for both the KSS and OKS. There was also no statistical significance in cadence, walking speed, stride length and stance time, peak stride, mid support and push-off forces.

Conclusion

This study corroborates a previous study by the same authors that showed equally good results in clinical outcome and gait between the conventional single radius and medial pivot designs under stringent testing conditions.

Cite this article: Bone Joint J 2018;(1 Supple A)100-B:76–82.

Efficacy and safety of home-based exercises versus individualized supervised outpatient physical therapy programs after total knee arthroplasty: a systematic review and meta-analysis

PURPOSE

The aim of the present study was to evaluate the efficacy and safety of non-supervised home-based exercise versus individualized and supervised programs delivered in clinic-based settings for the functional recovery immediately after discharge from a primary TKA.

METHODS

Medline, Embase, Cochrane, and PEDro databases were screened, from inception to April 2015, in search for randomized clinical trials (RCT) of home-based exercise interventions versus individualized and supervised outpatient physical therapy after primary TKA. Target outcomes were: knee range of motion (ROM), patient-reported pain and function, functional performance, and safety. Risk of bias was assessed with the PEDro scale. After assessing homogeneity, data were combined using random effects meta-analysis and reported as standardized mean differences or mean differences. We set a non-inferiority margin of four points in mean differences.

RESULTS

The search and selection process identified 11 RCT of moderate quality and small sample sizes. ROM active extension data suitable for meta-analysis was available from seven studies with 707 patients, and ROM active flexion from nine studies with 983 patients. Most studies showed no difference between groups. Pooled differences were within the non-inferiority margin. Most meta-analyses showed significant statistical heterogeneity.

CONCLUSION

Short-term improvements in physical function and knee ROM do not clearly differ between outpatient physiotherapy and home-based exercise regimes in patients after primary TKA; however, this conclusion is based on a meta-analysis with high heterogeneity.

LEVEL OF EVIDENCE

I.

Cruciate Retaining compared with Posterior Stabilised Nexgen total knee arthroplasty: results at 10 years in a matched cohort

INTRODUCTION Debate has persisted for many years about whether to sacrifice or replace the posterior cruciate ligament when performing total knee arthroplasty. A paucity of long-term follow-up studies comparing outcomes between cruciate-retaining and posterior-stabilised knees exist. We aimed to compare results at ten-year follow-up. METHODS A matched paired study comparing a cohort of 107 Zimmer Nexgen® Cruciate Retaining (CR) patients with a cohort of 107 Nexgen Posterior-Stabilised (PS) knees matched for age, sex, body mass index and preoperative American Knee Society score was undertaken. All patients underwent independent clinical assessment and knee society scoring preoperatively and at 1, 3, 5, 7 and 10 years postoperatively. RESULTS Fifty-three patients (49.5%) in the CR group and 44 patients (41.1%) in the PS group were alive at 10-year follow-up. There were no significant differences between the CR and PS groups with regards to functional assessment (P = 0.95), overall range of movement (P = 0.46) or patient satisfaction (P = 1.0) at 10 years. However, there was a significantly better score improvement in range of movement in PS knees compared with CR knees (P = 0.027). There were six revisions (5.6%) in the PS group and 1 (0.93%) in the CR group (P = 0.12). Both CR and PS knees showed excellent survivorship with no significant difference at 10 years (P = 0.068). CONCLUSIONS There were no significant differences in functional score, overall range of motion or patient satisfaction between the Nexgen cruciate retaining and posterior stabilised total knee arthroplasty at 10-year follow-up. However, PS knees had a greater score improvement in range of motion compared with CR knees.

Preemptive analgesia by using celecoxib combined with tramadol/APAP alleviates post-operative pain of patients undergoing total knee arthroplasty

OBJECTIVE

This study was aimed to evaluate the efficacy of preemptive analgesia (PA) by using celecoxib combined with low-dose tramadol/acetaminophen (tramadol/APAP) in treating post-operative pain of patients undergoing unilateral total knee arthroplasty (TKA).

METHODS

A total of 132 patients scheduled for TKA were included in this study. Three-day pre-operative medication was administrated in PA group with subsequent effective intra- and post-operative multimodal analgesia, while control patients received multimodal analgesia without PA. Visual analog scale (VAS) was utilized to assess the pain intensity at rest and during movement. VAS scores of participants were recorded 3 days before surgery, 1 day, 3 days, 1 week, 3 weeks, 6 weeks, 3 months, 6 months, and 12 months postoperatively. Moreover, the length of hospital stay, expense of hospitalization, C-reactive protein (CRP) values during hospitalization, and complications during medication were also recorded.

RESULTS

PA showed superiority over control at 3 weeks (P = 0.013) and 6 weeks (P = 0.046) in resting pain, and 1 week (P = 0.015), 3 weeks (P = 0.003), 6 weeks (P = 0.003) and 3 months (P = 0.012) postoperatively in movement pain. There was no statistically significant difference in the length of hospital stay, total expense, CRP values, as well as complications.

CONCLUSIONS

Based on satisfactory intra- and post-operative analgesia, PA by 3-day administration of celecoxib and low-dose tramadol/APAP might be an effective and safe therapy regarding patients undergoing TKA in terms of alleviating post-operative pain.

Do outcomes reported in randomised controlled trials of joint replacement surgery fulfil the OMERACT 2.0 Filter? A review of the 2008 and 2013 literature

BACKGROUND

It is not known, whether outcome reporting in trials of total joint arthroplasty in the recent years is adequate or not. Our objective was to assess whether outcomes reported in total joint replacement (TJR) trials fulfil the Outcome Measures in Rheumatology (OMERACT) Filter 2.0.

METHODS

We systematically reviewed all TJR trials in adults, published in English in 2008 or 2013. Searches were conducted in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Two authors independently applied the inclusion criteria for the studies, and any disagreement was resolved with a third review author. All outcome measures were abstracted using a pre-piloted standardised data extraction form and assessed for whether they mapped to one of the three OMERACT Filter 2.0 core areas: pathophysiological, life impact, and death.

RESULTS

From 1635 trials identified, we included 70 trials (30 in 2008 and 40 in 2013) meeting the eligibility criteria. Twenty-two (31%) trials reported the three essential OMERACT core areas. Among the 27 hip replacement surgery trials and 39 knee replacement surgery trials included, 11 hip (41%) and nine knee (23%) trials reported all three essential OMERACT core areas. The most common outcome domains/measures were pain (20/27, 74%) and function (23/27, 85%) in hip trials and pain (26/39, 67%) and function (27/39, 69%) in knee trials. Results were similar for shoulder and hand joint replacement trials.

CONCLUSIONS

We identified significant gaps in the measurement of OMERACT core outcome areas in TJR trials, despite the majority reporting outcome domains of pain and function. An international consensus of key stakeholders is needed to develop a core domain set for reporting of TJR trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014009216.

Outcome Measures Used in Arthroplasty Trials: Systematic Review of the 2008 and 2013 Literature

OBJECTIVE

Previously published literature assessing the reporting of outcome measures used in joint replacement randomized controlled trials (RCT) has revealed disappointing results. It remains unknown whether international initiatives have led to any improvement in the quality of reporting and/or a reduction in the heterogeneity of outcome measures used. Our objective was to systematically assess and compare primary outcome measures and the risk of bias in joint replacement RCT published in 2008 and 2013.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL for RCT investigating adult patients undergoing joint replacement surgery. Two authors independently identified eligible trials, extracted data, and assessed risk of bias using the Cochrane tool.

RESULTS

Seventy RCT (30 in 2008, 40 in 2013) met the eligibility criteria. There was no significant difference in the number of trials judged to be at low overall risk of bias (n = 6, 20%) in 2008 compared with 2013 [6 (15%); chi-square = 0.302, p = 0.75]. Significantly more trials published in 2008 did not specify a primary outcome measure (n = 25, 83%) compared with 18 trials (45%) in 2013 (chi-square = 10.6316, p = 0.001). When specified, there was significant heterogeneity in the measures used to assess primary outcomes.

CONCLUSION

While less than a quarter of trials published in both 2008 and 2013 were judged to be at low overall risk of bias, significantly more trials published in 2013 specified a primary outcome. Although this might represent a temporal trend toward improvement, the overall frequency of primary outcome reporting and the wide heterogeneity in primary outcomes reported remain suboptimal.

Will Total Knee Replacement Ever Provide Normal Knee Function?

Knee osteoarthritis or gonarthrosis is considered the most common joint disease, affecting more than 70% of subjects aged over 65 years. Its occurrence is increasing with age and is more problematic with the current rise in the incidence of obesity. In severe and advanced cases, total knee arthroplasty is recommended as a gold standard therapy for pain relief, restoration of normal knee function, and quality of life improvement. There are numerous controversies whether total knee arthroplasty is able to reach and provide end-point outcomes and restore previous function of the knee joint. Studies suggest that the surgeons’ experience, type of prosthesis used, associated pathology, underlying pathologies, risk factors, continuous passive movement, and patient expectations about the surgery may influence the outcomes to a great extent. “Normal knee function” is a statement that is hardly defined in the current literature, as authors usually refer to subjective results when analyzing outcomes. Objective results may be more straightforward, but they do not always symbolize the actual state that the patient is reporting or the actual quality of life. Our objective was to analyze and present summaries of the current literature regarding normal knee function restoration after total knee replacement surgery. Our literature review results confirm the hypothesis that subjective and objective results are difficult to interpret and unravel. Complex future trials may bring supplementary and clearer conclusions regarding knee function and kinematics, clinical improvement, patient satisfaction, and quality of life.

A Randomized Clinical Trial Comparing Posterior Cruciate-Stabilizing vs Posterior Cruciate-Retaining Prostheses in Primary Total Knee Arthroplasty: 10-Year Follow-Up

BACKGROUND

This 10-year follow-up compares health-related quality of life (HRQL) and reoperations in 100 subjects who were randomized to receive posterior cruciate ligament substituting (PS) or posterior cruciate ligament retaining (CR) total knee arthroplasty. We previously reported 2-year results.

METHODS

Subjects were enrolled preoperatively and randomized at surgery. Subjects completed HRQL questionnaires at all evaluation points. Subjects were re-evaluated at 2 and 10 years with reoperations determined through regional medical record review and patient report.

RESULTS

Over 10 years, 25 (25%) subjects died, 2 subjects were revised and withdrew, and 11 (11%) subjects were lost to follow-up. Of survivors, 62 of 75 (83%) were evaluated at 10 years. Twenty-eight (37%) subjects provided HRQL, radiographic, and reoperation status, 28 (37%) subjects completed HRQL evaluations and reoperation status only, and 6 (8%) subjects provided radiographic and reoperation follow-up. Both groups retained good HRQL between 2 and 10 years with no group differences noted (P > .35). One revision (CR subject), secondary to deep joint infection, occurred within 2 years with 1 further revision (PS subject) occurring at 3 years postoperatively. One subject (PS subject) required manipulation under anesthesia within 3 months of surgery. Four subjects required late patellar resurfacing (1 CR subject, 3 PS subjects) but were retained in the 10-year evaluation. Overall, reoperations were not significantly different between groups (P = .26).

CONCLUSION

Over 10 years postoperatively, both the PS and CR total knee arthroplasty performed well with subjects reporting acceptable levels of HRQL up to 10 years postoperatively; low levels of revision or reoperation were reported in both groups.

Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty for osteoarthritis with severe varus deformity

Objective

The aim of this study was to compare the radiological and functional results of posterior cruciate ligament (PCL) – retaining and posterior-stabilized total knee arthroplasties in patients with severe varus gonarthrosis.

Methods

Medical records of 112 knees of 96 patients who underwent total knee arthroplasty for severe varus (≥15°) were reviewed. PCL-retaining and PCL-stabilizing groups consisted of 58 and 54 knees, respectively. Mean follow-up time was 56.6 months (range: 24–112 months). Knee Society (KS) clinical rating system was used in clinical evaluation. Range of motion, degree of flexion contracture, postoperative alignment, and complication rates were compared between the groups.

Results

Mean preoperative mechanical tibiofemoral angle was 20.1° in varus alignment, and was restored to 4.6° in valgus postoperatively. No statistically significant differences were found between PCL-stabilizing and PCL-retaining groups when KS knee scores, function scores, and flexion arc were evaluated. Two patients in PCL-retaining group underwent revision surgery due to aseptic loosening of tibial component. One patient in PCL-stabilizing group needed arthrotomy due to patellar clunk syndrome.

Conclusion

There were no notable differences between the 2 groups and PCL-retaining design had outcomes as good as PCL-stabilizing total knee implant in osteoarthritic knees with severe varus deformity.

Level of evidence

Level III, Therapeutic study.

Intra- and Inter-Examiner Reliability in Angular Measurements of the Knee with a Smartphone Application

Goniometric smartphone applications to measure joint angles offer greater practicality and accessibility, which makes them potential alternatives to a conventional goniometer. The aim of the present study was to evaluate the intra- and inter-examiner reliability in measuring the angles of the range of motion of the knee with the use of the ROM© goniometric smartphone application.

The total of 34 young healthy women with an at least 20° limitation in knee extension range of motion participated in the study. Angular measurements of knee flexion in the dominant leg were performed with the aid of the smartphone application by three trained examiners for the evaluation of the inter-examiner reliability. The second evaluation was carried out after a 48-hour period for the determination of the intra-examiner reliability.

The proposed method demonstrated excellent intra-examiner (intra-class correlation coefficient [ICC] > 0.80) and inter-examiner (ICC > 0.90) reliability, with good intra-examiner (

The findings reveal that the ROM© goniometric smartphone application can be considered a useful tool for the evaluation of the knee range of motion in healthy women.

Effect of different postoperative limb positions on blood loss and range of motion in total knee arthroplasty: An updated meta-analysis of randomized controlled trials

BACKGROUND

Postoperative limb positioning has been reported to be an efficient and simple way to reduce blood loss and improve range of motion following total knee arthroplasty (TKA). This meta-analysis was designed to compare the effectiveness of two different limb positions in primary TKA.

MATERIALS AND METHODS

A meta-analysis of the PubMed, CENTRAL, Web of Science, EMBASE and Google Search Engine electronic databases was performed. In this meta-analysis, two postoperative limb positions were considered: mild-flexion (flexion less than 60°) and high-flexion (flexion at 60° or more). The subgroups were analysed using RevMan 5.3.

RESULTS

Nine RCTs were included with a total sample size of 913 patients. The mild- and high-flexion positions significantly reduced postoperative total blood loss (P = 0.04 and P = 0.01; respectively). Subgroup analysis indicated that knee flexion significantly reduced hidden blood loss when the knee was fixed in mild-flexion (P = 0.0004) and significantly reduced transfusion requirements (P = 0.03) and improved range of motion (ROM) (P < 0.00001) when the knee was fixed in high-flexion. However, the rates of wound-related infection, deep venous thrombosis (DVT) and pulmonary embolism (PE) did not significantly differ between the two flexion groups.

CONCLUSION

This meta-analysis suggests that mild- and high-flexion positions have similar efficacy in reducing total blood loss. In addition, subgroup analysis indicates that the mild-flexion position is superior in decreasing hidden blood loss compared with high-flexion; the high-flexion position is superior to mild-flexion in reducing transfusion requirements and improving postoperative ROM. Thus, the use of the high-flexion position is a viable option to reduce blood loss in patients following primary TKA without increasing the risk of wound-related infection, DVT or PE.

Effects of Group-Based Exercise on Range of Motion, Muscle Strength, Functional Ability, and Pain During the Acute Phase After Total Knee Arthroplasty: A Controlled Clinical Trial

Study Design Prospective observational study including a historical control group. Background The extent to which group-based exercise (G-EXE) improves knee range of motion (ROM), quadriceps strength, and gait ability is similar to that of individualized exercise (I-EXE) at 6 weeks and 8 months after total knee arthroplasty (TKA). However, the benefits of G-EXE for patients during the acute recovery phase after TKA remain unclear. Objective To determine the effects of G-EXE during the acute recovery phase after TKA on knee ROM, quadriceps strength, functional ability, and knee pain. Methods Two hundred thirty-one patients participated in G-EXE in addition to regular ambulation and activities-of-daily-living exercises twice daily during the hospital stay. Outcomes were compared to those of a retrospectively identified, historical control group (I-EXE group [n = 206]) that included patients who performed exercises identical to those performed by the G-EXE group. The outcomes included knee ROM, quadriceps strength, pain intensity, and timed up-and-go test score at 1 month before surgery and at discharge. Analyses were adjusted for age, body mass index, sex, length of hospital stay, and preoperative values. Results Changes in ROM of knee flexion and extension (P<.001) and quadriceps strength (P<.001) were significantly better in the G-EXE group than those in the I-EXE group at discharge. The pain intensity improved more in the G-EXE group than in the I-EXE group at discharge (P<.001). However, the changes in the timed up-and-go scores were not significantly different. Conclusion Patients performing G-EXE in addition to regular ambulation and activities-of-daily-living exercises demonstrated greater changes in knee ROM, quadriceps strength, and knee pain than those performing I-EXE in addition to regular ambulation and activities-of-daily-living exercises. The nonrandomized, asynchronous design decreases certainty of these findings. Level of Evidence Therapy, level 2b. J Orthop Sports Phys Ther 2016;46(9):742-748. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6409.

Posterior cruciate-substituting total knee replacement recovers the flexion arc faster in the early postoperative period in knees with high varus deformity: a prospective randomized study

INTRODUCTION

Posterior cruciate retention (CR) and substitution (PS) has been controversial in knee replacement surgery. Satisfactory medium and long-term results have been reported in knees with and without deformity but there are limited studies about early functional comparison in terms of recovery of flexion arc, stair activity, walking ability and straight leg raising, especially, in early postoperative period in knees with deformity. Therefore, we aimed to compare the flexion arc in CR and PS knees in postoperative first year including early postoperative days prospectively.

METHODS

Consecutive patients with a deformity of >10° were included and allocated to CR and PS groups randomly. KSS and Feller-patella scores were recorded both preoperatively and postoperatively (1st, 2nd, 3rd and 12th months). Flexion and extension were measured both preoperatively and postoperatively (1st, 2nd, 3rd day and discharge day as well as 1st, 2nd, 3rd and 12th months). Visual analog scale (VAS) was recorded postoperatively at the 1st, 2nd, 3rd and discharge day and at 1st, 2nd, 3rd and 12th months. The walking ability, stair activity and straight leg raising were recorded. Patients were also examined at the last visit with minimum 7-year follow-up with KSS, Feller-patella and VAS scores. Their mean flexion arcs were measured and recorded.

RESULTS

There were 61 TKR evaluated. KSS knee and function scores at the 3rd month and KSS Knee Score at 1st year were superior in PS knees (p = 0.029, p = 0.046, p = 0.026). Flexion arc was found larger on day 1, 2, 3 and discharge day, and at 1st, 2nd, 3rd and 12th month in PS group (p = 0.048, p = 0.002, p = 0.027, p = 0.043, p = 0.014, p = 0.003, p = 0.002, p = 0.018). Walking and stair activity showed no difference but straight leg raising was better in CR knees (p = 0.02). Mean flexion arc was larger in PS knees at the last visit after 7 years (119.0° ± 7.5° in PS and 113.8° ± 8.7° in CR, p = 0.02). There was no revision required in that time interval. The other parameters were similar between groups.

CONCLUSIONS

PS knees gained active flexion arc faster and larger. But straight leg raising activity recovered early in CR knees. Both types of prosthesis produced satisfactory outcome. PS and CR TKRs can be performed with the same performance in osteoarthritic knees even with high varus deformity.

LEVEL OF EVIDENCE

Prospective Randomized Controlled Trial, Level II.

Full-thickness cartilage-based posterior femoral condylar offset. Influence on knee flexion after posterior-stabilized total knee arthroplasty

BACKGROUND

The association between posterior condylar offset (PCO) and maximal knee flexion remains controversial. The measured PCO in the previous studies is usually determined on the plain radiographs without taking into account the cartilage thickness.

HYPOTHESIS

Full-thickness cartilage-based PCO is a valid criterion to compare preoperative and postoperative offset, and has a significant influence on postoperative knee flexion after total knee arthroplasty.

MATERIALS AND METHODS

Ninety-five patients (107 knees) who underwent posterior-stabilized total knee arthroplasty were enrolled in a prospective study. Intra-operative measurement of cartilage thickness of the posterior femoral condyle was documented in all patients. Preoperative and postoperative radiographic PCO was measured respectively on the true lateral view of the knee. True PCO was adjusted by adding cartilage thickness of the posterior femoral condyle. The relationship between the change in knee flexion and PCO difference was assessed using Pearson correlation analysis.

RESULTS

The postoperative radiographic PCO difference (2.01±2.05mm) was significantly greater than the true PCO difference (0.09±2.12mm). The mean postoperative change in maximum knee flexion angle was 5.4°±9.9°. No significant correlation was found between PCO difference and the change in knee flexion, regardless of radiographic (P=0.232) or cartilage-based measurements (P=0.693).

CONCLUSIONS

Full-thickness cartilage-based PCO is an optimal criterion to estimate the change in PCO before and after total knee arthroplasty. However in this study, neither cartilage-based nor radiographic PCO appeared to have a significant influence on postoperative knee flexion after posterior-stabilized total knee arthroplasty.

LEVEL OF EVIDENCE

Level 4 Cohort Study.

Changes in the three-dimensional load-bearing axis after mobile-bearing total knee arthroplasty

BACKGROUND

The purpose of this study was to assess changes in the three-dimensional (3D) load-bearing mechanical axis (LBMA) preoperatively and at 3 weeks and more than 1-year follow-up after total knee arthroplasty (TKA), and effects of the degree of constraint in the anteroposterior (AP) direction because of the retention of the posterior cruciate ligament (PCL) and the implant design on the changes in LBMA.

METHODS

We evaluated 157 knees from 131 patients, including 79 knees that received meniscal-bearing-type (PCL-retaining) and 78 knees that received rotating-platform-type (PCL-substituting) prostheses. Quantitative 3D computed tomography was used to assess changes in the location of the pre- and postoperative LBMA at the tibial plateau level.

RESULTS

Changes in the 3D axis were mainly found from medial to lateral and posterior to anterior in both implant designs with no significant differences. Change in the mediolateral (ML) direction was improved soon after TKA, but change in the AP direction improved more gradually over time. The different constraints in the AP direction because of the retention of the PCL and different implant designs did not affect the changes in the LBMA.

CONCLUSIONS

The LBMA in the AP direction more than 1 year postoperatively, as well as the LBMA in the ML direction at 3 weeks, appears to shift toward the location found in normal knees after TKA, regardless of the type of prosthetic constraint. These changes may be an important factor that influences the periarticular knee bone mineral density which load bearing may be related to.

LEVEL OF EVIDENCE

Level II, Prognostic study.

Posterior Cruciate Ligament Retention versus Posterior Stabilization for Total Knee Arthroplasty: A Meta-Analysis

Introduction

Although being debated for many years, the superiority of posterior cruciate-retaining (CR) total knee arthroplasty (TKA) and posterior-stabilized (PS) TKA remains controversial. We compare the knee scores, post-operative knee range of motion (ROM), radiological outcomes about knee kinematic and complications between CR TKA and PS TKA.

Methods

Literature published up to August 2015 was searched in PubMed, Embase and Cochrane databases, and meta-analysis was performed using the software, Review Manager version 5.3.

Results

Totally 14 random control trials (RCTs) on this topic were included for the analysis, which showed that PS and CR TKA had no significant difference in Knee Society knee Score (KSS), pain score (KSPS), Hospital for Special Surgery score (HSS), kinematic characteristics including postoperative component alignment, tibial posterior slope and joint line, and complication rate. However, PS TKA is superior to CR TKA regarding post-operative knee range of motion (ROM) [Random Effect model (RE), Mean Difference (MD) = -7.07, 95% Confidential Interval (CI) -10.50 to -3.65, p<0.0001], improvement of ROM (Fixed Effect model (FE), MD = -5.66, 95% CI -10.79 to -0.53, p = 0.03) and femoral-tibial angle [FE, MD = 0.85, 95% CI 0.46 to 1.25, p<0.0001].

Conclusions

There are no clinically relevant differences between CR and PS TKA in terms of clinical, functional, radiological outcome, and complications, while PS TKA is superior to CR TKA in respects of ROM, while whether this superiority matters or not in clinical practice still needs further investigation and longer follow-up.

Preservation of the PCL when performing cruciate-retaining TKA: Is the tibial tuberosity a reliable predictor of the PCL footprint location?

PURPOSE

Reconstruction of the joint line is crucial in total knee arthroplasty (TKA). A routine height of tibial cut to maintain the natural joint line may compromise the preservation of the PCL. Since the PCL footprint is not accessible prior to tibial osteotomy, it seems beneficial to identify a reliable extraarticular anatomic landmark for predicting the PCL footprint and being visible within standard TKA approach. The fibula head predicts reliably the location of PCL footprint; however, it is not accessible during TKA. The aim of this study now was to analyze whether the tibial tuberosity can serve as a reliable referencing landmark to estimate the PCL footprint height prior to tibial cut.

METHODS

The first consecutive case series included 216 CR TKA. Standing postoperative lateral view radiographs were utilized to measure the vertical distance between tibial tuberosity and tibial osteotomy plane. In the second case series, 223 knee MRIs were consecutively analyzed to measure the vertical distance between tibial tuberosity and PCL footprint. The probability of partial or total PCL removal was calculated for different vertical distances between tibial tuberosity and tibial cutting surface.

RESULTS

The vertical distance between the tibial tuberosity and tibial cut averaged 24.7 ± 4 mm. The average vertical distance from tibial tuberosity to proximal and to distal PCL footprint was found to be 22 ± 4.4 and 16 ± 4.4 mm, respectively. Five knees were considered at 50% risk of an entire PCL removal after CR TKA.

CONCLUSIONS

Current surgical techniques of tibial preparation may result in partial or total PCL damage. Tibial tuberosity is a useful anatomical landmark to locate the PCL footprint and to predict the probability of its detachment pre-, intra-, and postoperatively. This knowledge might be useful to predict and avoid instability, consecutive pain, and dissatisfaction after TKA related to PCL insufficiency.

LEVEL OF EVIDENCE

III.

Comparison of High-Flexion and Conventional Implants in Total Knee Arthroplasty: A Meta-Analysis

Background

The purpose of this study was to evaluate whether high-flexion prostheses are superior to conventional prostheses after total knee arthroplasty (TKA).

Material/Methods

We searched the PubMed and Embase databases for randomized trials and cohort studies comparing high-flexion with conventional knee implants. The heterogeneity across studies was examined by I² and Cochran’s Q-tests. Then the overall weighted mean differences of range of motion (ROM) and knee functional scores were evaluated.

Results

A total of 16 trials involving 2643 knees met our inclusion criteria. The results revealed that high-flexion implants were superior to conventional implants in the improvement of range of motion (weighted mean difference, 2.92; 95% CI, 1.63–4.22; p<0.0001). The clear advantage of high-flex PS (posterior stabilized) as well as high-flex CR (cruciate retaining) implants was found in ROM when compared to PS implants (2.73; 95% CI, 1.27–4.20; p=0.0003) and CR implants (3.24; 95% CI, 0.28–6.20; p=0.003), respectively. However, there was no difference in Knee Society Scores (0.42; 95% CI, −0.60–1.43; p=0.42), Knee Society function (0.37; 95% CI, −1.48–2.22; p=0.70) and Hospital for Special Surgery scores (0.26; 95% CI, −0.47–1.00; p=0.48) between high-flexion and conventional groups.

Conclusions

The current meta-analysis revealed that high-flexion implants were superior to conventional implants in the improvement of ROM but not in functional outcome scores.

Patients achieved greater range of movement when using high-flexion implants

PURPOSE

NexGen Legacy Posterior Stabilized high-flexion prostheses (LPS-Flex) have been popularized as an alternative to NexGen standard prostheses (LPS) in total knee arthroplasty (TKA). Advocates of this new generation prosthesis suggest improved postoperative knee flexion. The purpose of this study was to summarize the best evidence for comparing the range of motion (ROM) and functional outcomes of LPS-Flex prostheses and LPS in TKA.

METHODS

Electronic databases were systematically searched to identify relevant randomized controlled trials (RCTs). The last date for our research was July 2014. Our search strategy was followed the requirements of the Cochrane Library Handbook. The methodological quality was assessed, and the data were extracted independently by two authors.

RESULTS

Nine studies that included 978 knees met our inclusion criteria for review. The results showed that there was larger postoperative ROM (1.62, 95% CI 0.52-2.72) in the LPS-Flex group than in the LPS group. There was not a statistically significant difference in the clinical functional scores and complications between the LPS-Flex group and the LPS group in TKA. The pooled mean differences were as follows: total KSS, -0.64 (95% CI -1.41 to 0.13); functional KSS, -0.53 (95% CI -1.51 to 0.45); HSS, 0.23 (95% CI -0.87 to 1.33); complications, 0.49 (95% CI 0.20-1.24); and radiolucent lines, 1.56 (95% CI 0.68-3.55).

CONCLUSIONS

The preliminary results indicate that the NexGen LPS-Flex prosthesis provides an alternative to the NexGen LPS prosthesis, with greater range of motion and without severe complications or radiographic outcomes. The clinical advantages were not shown in the KSS or the HSS. Thus, the selection of a high-flexion prosthesis should depend on the characteristics of the patient, particularly high motivation and poor preoperative ROM. The potential benefits in the medium- and long-term outcomes require confirmation by larger, multicenter and well-conducted RCTs.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Condylar-stabilizing tibial inserts do not restore anteroposterior stability after total knee arthroplasty

The Triathlon condylar-stabilizing (CS) lipped insert is designed to provide anteroposterior (AP) stability of the posterior-stabilized (PS) insert, without a post. The purpose of this study was to compare the AP stability of the knee in patients with Triathlon CS and PS total knee arthroplasty (TKA) with midterm follow-up. Thirty-one patients received a Triathlon PS TKA in one knee and a Triathlon CS TKA in the contralateral knee, and 28 patients were followed up with a minimum duration of 5years. Although there was no difference in functional outcomes, the posterior displacement was significantly greater in the CS TKA group than in the PS TKA group (P<0.001). The Triathlon CS lipped insert could not restore posterior stability with PCL sacrifice.