Residual knee pain and functional outcome following total knee arthroplasty in osteoarthritic patients

Optimal Implant Positioning Following Total Knee Arthroplasty Using Predictive Dynamic Simulation

In this paper, a novel method is proposed for the determination of the optimal subject-specific placement of knee implants based on predictive dynamic simulations of human movement following total knee arthroplasty (TKA). Two knee implant models are introduced. The first model is a comprehensive 12-degree-of-freedom (DoF) representation that incorporates volumetric contact between femoral and tibial implants, as well as patellofemoral contact. The second model employs a single-degree-of-freedom equivalent kinematic (SEK) approach for the knee joint. A cosimulation framework is proposed to leverage both knee models in our simulations. The knee model is calibrated and validated using patient-specific data, including knee kinematics and ground reaction forces. Additionally, quantitative indices are introduced to evaluate the optimality of implant positioning based on three criteria: balancing medial and lateral load distributions, ligament balancing, and varus/valgus alignment. The knee implant placement is optimized by minimizing the deviation of the indices from their user-defined desired values during predicted sit-to-stand motion. The method presented in this paper has the potential to enhance the results of knee arthroplasty and serve as a valuable instrument for surgeons when planning and performing this procedure.

Safety and efficacy of an allogeneic adipose-derived mesenchymal stem cell preparation in the treatment of knee osteoarthritis: A Phase I/IIa randomised controlled trial

Objectives

To assess the safety and efficacy of an allogeneic adipose-derived mesenchymal stem cell preparation (MAG200) in the treatment of knee osteoarthritis over 12 months.

Design

A single-centre, double-blind, ascending dose, randomised controlled trial. 40 participants with moderate knee osteoarthritis were randomised to receive a single intra-articular injection of MAG200 (dose cohorts:10, 20, 50, 100 ​× ​106 ​cells) or placebo. Primary objectives were safety and efficacy according to a compound responder analysis of minimal clinically important difference in pain (numerical pain rating scale [NPRS]) and function (Knee Injury and Osteoarthritis Outcome Score - Function in Daily Living subscale [KOOSADL]) at month 12. Secondary efficacy outcomes included changes from baseline in patient reported outcome measures and evaluation of disease-modification using quantitative MRI.

Results

Treatment was well tolerated with no treatment-related serious adverse events. MAG200 cohorts reported a greater proportion of responders than placebo and demonstrated clinical and statistically significant improvement in pain and clinically relevant improvement in all KOOS subscales. MAG200 demonstrated a reproducible treatment effect over placebo, which was clinically relevant for pain in the 10 ​× ​106 dose cohort (mean difference NPRS:-2.25[95%CI:-4.47,-0.03, p ​= ​0.0468]) and for function in the 20 ​× ​106 and 100 ​× ​106 dose cohorts (mean difference KOOSADL:10.12[95%CI:-1.51,21.76, p ​= ​0.0863] and 10.81[95%CI:-1.42,23.04, p ​= ​0.0810] respectively). A trend in disease-modification was observed with improvement in total knee cartilage volume in MAG200 10, 20, and 100 ​× ​106 dose cohorts, with progression of osteoarthritis in placebo, though this was not statistically significant. No clear dose response was observed.

Conclusion

This early-phase study provides supportive safety and efficacy evidence to progress MAG200 to later-stage trial development.

Trial registration

ACTRN12617001095358/ACTRN12621000622808.

Low-Degree Tibial Slope Angle Prevents Component Overhang by Enlarging the Lateral Plateau Surface Area in Total Knee Arthroplasty

This study aimed to investigate whether overhang or underhang around the tibial component that occurs during the placement of tibial baseplates was affected by different slope angles of the tibial plateau and determine the changes in the lateral and medial plateau diameters while changing the slope angle in total knee arthroplasty. Three-dimensional tibia models were reconstructed using the computed tomography scans of 120 tibial dry bones. Tibial plateau slope cuts were performed with 9, 7, 5, 3, and 0 degrees of slope angles 2-mm below the subchondral bone in the deepest point of the medial plateau. Total, lateral, and medial tibial plateau areas and overhang/underhang rates were measured at each cut level. Digital implantations of the asymmetric and symmetric tibial baseplates were made on the tibial plateau with each slope angles. Following the implantations, the slope angle that prevents overhang or underhang at the bone border and the slope angle that has more surface area was identified. A significant increase was noted in the total tibial surface area, lateral plateau surface area, and lateral anteroposterior distance, whereas the slope cut angles were changed from 9 to 0 degrees in both gender groups. It was found that the amount of posteromedial underhang and posterolateral overhang increased in both the asymmetric and symmetric tibial baseplates when the slope angle was changed from 0 to 9 degrees. Although the mediolateral diameter did not change after the proximal tibia cuts at different slope angles, the surface area and anteroposterior diameter of the lateral plateau could change, leading to increased lateral plateau area. Although prosthesis designs are highly compatible with the tibial surface area, it should be noted that the component overhangs, especially beyond the posterolateral edge, it can be prevented by changing the slope cut angle in males and females.

The Role of Stability and Alignment in Improving Patient Outcomes After Total Knee Arthroplasty

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Total knee arthroplasty (TKA) is an effective treatment option for many patients, but a small group of patients are dissatisfied following TKA.

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Alignment, in combination with balance, stability, and knee kinematics, is an important modifiable surgical factor that can affect patient outcomes.

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Driven by the subset of dissatisfied patients after TKA, new techniques have evolved in the search for a more anatomic reconstruction of individual knee morphology and a more accurate approximation of the individual lower-extremity alignment.

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There is a need to optimize 3 aspects of TKA to improve patient outcomes-mechanical tooling processes, implants that resurface the epiphysis, and techniques that respect the variable anatomy of patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Knee Ablation Approaches

Genicular nerve radiofrequency ablation has quickly become one of the most promising interventions for chronic knee pain secondary to osteoarthritis, with consistent improvements in pain and function. Although there are multiple techniques using slightly variable lesion locations, cannulas, lesion types, and imaging modalities, the clinical effectiveness targeting the anterior branches of the superior medial, superolateral, and inferior medial has reproducibly demonstrated clinically and statistically significant improvements up to 24 months after the procedure with minimal adverse events. This article summarizes the current knowledge of the sensory innervation of the knee joint, the principles of radiofrequency ablation, and the current literature on clinical outcomes.

Personalized alignment in total knee arthroplasty: current concepts

Traditionally in total knee arthroplasty (TKA), a post-operative neutral alignment was the gold standard. This principle has been contested as functional outcomes were found to be inconsistent. Analysis of limb alignment in the non-osteoarthritic population reveals variations from neutral alignment and consideration of a personalized or patient-specific alignment in TKA is challenging previous concepts. The aim of this review was to clarify the variations of current personalized alignments and to report their results. Current personalized approaches of alignment reported are: kinematic, inverse kinematic, restricted kinematic, and functional. The principle of “kinematic alignment” is knee resurfacing with restitution of pre-arthritic anatomy. The aim is to resurface the femur maintaining the native femoral joint line obliquity. The flexion and extension gaps are balanced with the tibial resection. The principle of the “inverse kinematic alignment” is to resurface the tibia with similar medial and lateral bone resections in order to keep the native tibial joint line obliquity. Gap balancing is performed by adjusting the femoral resections. To avoid reproducing extreme anatomical alignments there is “restricted kinematic alignment” which is a compromise between mechanical alignment and true kinematic alignment with a defined safe zone of alignment. Finally, there is the concept of “functional alignment” which is an evolution of kinematic alignment as enabling technology has progressed. This is obtained by manipulating alignment, bone resections, soft tissue releases, and/or implant positioning with a robotic-assisted system to optimize TKA function for a patient’s specific alignment, bone morphology, and soft tissue envelope. The aim of personalizing alignment is to restore native knee kinematics and improve functional outcomes after TKA. A long-term follow-up remains crucial to assess both outcomes and implant survivorship of these current concepts.

Current state of total knee arthroplasty

Total knee arthroplasty (TKA) is a successful and cost-effective treatment for end-stage degenerative arthritis. The aging of society and an increase in the prevalence of obesity has led to increases in the prevalence of arthritis and the incidence of TKA. Currently, the total number of procedures in Korea per year has reached 90,000. With the rapid growth, we need to know about the current state of TKA. The purpose of this review is to summarize the recent literature regarding TKA. The main indication for TKA is end-stage arthritis with severe pain, reduced function, and no response to conservative management. Metal on the polyethylene-bearing surface and cobalt alloy are used in most TKAs. Despite good clinical outcomes and long-term survival rates after TKA in many papers, 20% of patients are dissatisfied with the outcome of surgery. To improve the patient’s satisfaction, surgeons should understand factors affecting patient’s satisfaction, including patient’s expectations, age, and preoperative mental state. Navigation-assisted surgery and robotic surgery have been introduced in knee arthroplasty to achieve more precise and accurate alignment. There is some evidence to suggest that computer-assisted surgery reduces revision rates. However, clinical efficacy is also controversial, and a long-term follow-up study is required. The common complications of TKA include infection, polyethylene wear, loosening, stiffness, periprosthetic fracture, and thromboembolism. An understanding of the potential complications and pitfalls of TKA is essential for prevention.

[Adjusted mechanical alignment: operative technique-Tips and tricks]

INTRODUCTION

Mechanical alignment (MA) is a standardized procedure that aims to achieve a neutrally aligned leg axis. An alignment of the prosthesis closer to the patient's anatomy can be an approach for better clinical outcomes. The surgical technique of adjusted mechanical alignment (aMA) presented here is a modified extension-gap-first technique that takes into account the natural ligamentous tension of the knee joint so that ligamentous releases can be avoided as far as possible.

INDICATION

The aMA technique can be used for primary and secondary varus gonarthrosis of up to 20° of varus.

SURGICAL TECHNIQUE

The aim of the operation is to achieve a balanced ligament tension through a femoral osseous correction rather than ligament releases. TEA and the sulcus line are marked to control the ligament-based femoral rotation. The osteophytes are removed to ensure a reliable ligament tension. A quantitative ligament tensioner is stretched with great care, and gap width as well as medial and lateral ligament tension are read off. In order to correct an extension gap asymmetry, instead of the typical medial soft tissue release, the asymmetry is compensated by a special femoral cutting block. Now, the flexion gap is assessed, whereby the transverse femoral rotation follows the soft tissue tension. The tensioner adjusts a rectangular flexion gap with balanced ligament tension. After a final balancing of the gaps, the femoral preparation is completed and the trial components are inserted. Here, the rotation of the tibial component is set by repeated flexion-extension cycles.

DISCUSSION AND CONCLUSION

The technique presented combines a measured-resection technique with individual ligament tension. The maximum deviation of the femoral alignment in the coronal plane from the neutral alignment is 2.5°. In order to avoid problems, it is recommended, as with the described technique, to achieve a component alignment based on the patient anatomy by adjusting the femoral component. The measured-resection technique carries the risk of flexion instability. With the gap-balancing technique symmetrical ligament tension can be achieved, assuming precise proximal tibial cuts. When aligning the femoral component rotation, flexion gap stability and patella tracking should be considered. Long-term studies of high case numbers are necessary to evaluate the good short-term results of the presented surgical technique.

Unicompartmental Knee Arthroplasty: US and Global Perspectives

Unicompartmental knee arthroplasty (UKA) is a treatment option for anteromedial osteoarthritis. Compared with total knee arthroplasty (TKA), UKA offers improved knee range of motion, functional recovery and decreased medical complications. Revision rates continue to be higher with UKA compared with TKA. With current UKA implants, there is no significant difference in mobile bearing or fixed bearing, or between cemented and cementless implants. Enabling technology, such as robotic-assisted surgery, has demonstrated improvements in component positioning, but no long-term difference in survival compared with traditional manual instruments.

Influence of Narrow Femoral Implants on Intraoperative Soft Tissue Balance in Posterior-Stabilized Total Knee Arthroplasty

BACKGROUND

Narrow femoral implants were developed to improve fit and prevent overhang in primary total knee arthroplasty (TKA). We compared intraoperative soft tissue balance between standard and narrow implants in posterior-stabilized (PS) TKA.

METHODS

We enrolled 30 consecutive patients with varus osteoarthritis undergoing PS TKA using an image-free navigation system. Standard and narrow femoral trial implants were inserted, and their soft tissue balance was measured. Subgroup analysis, based on the actual implanted femoral implant, was performed to assess the influence of narrow implants on soft tissue balance.

RESULTS

Narrow trial group had significantly larger joint component gaps than standard trial group at all measured flexion angles, except at 60° (P < .05). For the standard implant cohort, narrow trial group had significantly larger joint component gaps than standard trial group at 30°, 120°, and 135° flexion (P < .05). For the narrow implant cohort, narrow trial group had significantly larger joint component gaps than standard trial group at all measured flexion angles, except at 0° and 60° (P < .05). Narrow trial group had significantly larger varus ligament balance than standard trial group at 45° and 60° flexion (P < .05). The varus angles for standard implants were comparable between groups; however, narrow trial group had significantly larger varus angles for narrow implants than standard trial group at 45°, 60°, and 120° flexion (P < .05).

CONCLUSION

The medial-lateral dimension and volume of the femoral component may influence intraoperative soft tissue balance in PS TKA. The effects may be greater when narrow implants are selected to avoid component overhang.

Improved walking distance and range of motion predict patient satisfaction after TKA

PURPOSES

The focus in the evaluation of total knee arthroplasty has shifted from objective measures of implant position and knee function, to patient-reported outcome measures (PROMs). The relation between these two measures was investigated and the possibility of prediction of the patient satisfaction level was evaluated by defining thresholds for improvement of (1) range of motion (ROM), (2) 6-min walk test (6MWT), (3) sit-to-stand test (STS) and (4) quadriceps force after TKA?

METHODS

Fifty-seven patients were prospectively tested at preoperative and 6 months postoperative intervals. The ROM, 6MWT, STS-test and quadriceps force were evaluated. Two clusters were created based on the postoperative KOOS, OKS and the satisfaction subscore of the new KSS, cluster 1 consisted of patients with good to excellent PROMs, cluster 2 of patients with poorer PROMs. Patients in each cluster were more similar to each other than to those in the other cluster. Receiver operating characteristic (ROC)-curve analysis was used to identify thresholds for the functional outcomes that established cluster allocation. Multiple logistic regression was used to define a model to predict cluster allocation.

RESULTS

Patients with high postoperative PROMs (cluster 1 allocation) showed higher postoperative functional outcomes (p < 0.05). Thresholds for the improvement of ROM (≥ 5°, OR 6.3, 95% CI 1.23-31.84), 6MWT (≥ 50 m, OR 8.2, 95% CI 1.61-42.18) STS (≥ 1.05 s, OR 3, 95% CI 0.56-16.07) and normalized Q4 force (≥ 1.5 N/BMI, OR 2.5, 95% CI 0.49-12.89) were found to be predictors of cluster allocation. A model to predict the cluster allocation contained gender, ROM improvement and 6MWT improvement (sensitivity 91.1%, specificity 75%).

CONCLUSIONS

Thresholds for improvement of functional parameters can predict the patient satisfaction cluster. Patients, who are male, improve on the 6-min walk test with 50 m or more and have an increased range of motion of 5° or more, compared to the preoperative situation, are 6-8 times more likely of being satisfied after TKA. These tests are easy to use in clinical practice and can predict the level of patient satisfaction after TKA.

LEVEL OF EVIDENCE

Level II, prognostic study.

The effect of intensive exercise program and kinesiotaping following total knee arthroplasty on functional recovery of patients

Background

Total knee arthroplasty (TKA) is a gold standard for terminal term gonarthrosis patients in order to diminish pain, correct deformities, and regain stability. Postoperative functional recovery of patients depends on the current postoperative rehabilitation program to an important extent. The purpose of our study is to compare midterm functional level of gonarthrosis patients who were included in physiotherapy rehabilitation program following TKA with people in similar ages without any surgical indication nor intervention. We have aimed also to compare functionality of people who had additional kinesiotaping (KT) treatment with people who had conservative treatment only after knee arthroplasty.

Methods

Functional level and knee functionality of people in study were evaluated at the end of postoperative first month by 6-min walk test and Lysholm knee score respectively.

Results

There was no statistical difference between groups with and without TKA in terms of height, weight, body mass index, Lysholm score, and 6-min walk test score (p > 0.05). In patient group with TKA, people with postoperative KT treatment had greater 6-min walk test score for postoperative first month (p = 0.005).

Conclusion

TKA is considered a gold standard procedure in order to increase the quality of life and improve functionality of terminal term gonarthrosis patients. It is necessary to immediately control pain and edema of knee and apply intensive rehabilitation program aimed at muscle strengthening around hip and knee in order to increase the success of operation.

Evaluation of a nurse-led intervention to improve adherence to recommended guidelines for prevention of venous thromboembolism for hip and knee arthroplasty patients: A quasi-experimental study

AIMS AND OBJECTIVES

To measure adherence to a nurse-led evidence-based venous thromboembolism prevention programme (intervention) compared to usual care in hip and knee arthroplasty patients and associated clinical outcomes.

BACKGROUND

Venous thromboembolism morbidity and mortality of hospitalised patients is a major concern for health professionals. Venous thromboembolism prevention guidelines have been developed; however, adherence to guidelines is variable.

PARTICIPANTS

There were 410 potential participants who were adult patients that were booked for elective hip or knee arthroplasty at the two study sites during a 2-year period (2011-2013). Of these, 27 did not meet the inclusion criteria, and the remainder were eligible for inclusion in the study (intervention site n = 196 and control site n = 187, total population n = 383).

METHODS

This study adopted a quasi-experimental design, using an intervention and control study site, conducted in two private hospitals in a regional area in Australia.

RESULTS

The intervention group had a mean compliance score of 11.09, higher than the control group score of 7.19. This is equivalent to a compliance rate of 85% and 55%, respectively, and indicates that adherence at the study site was significantly higher. Patient adherence and outcomes in the postdischarge period were not significantly different between the study sites.

CONCLUSION

This study demonstrated a nurse-led intervention achieved high adherence with translating evidence-based guidelines into routine patient care for hip and knee arthroplasty patients. Nurses can be critical to implementing clinical practice guidelines and adopting preventive programmes in acute care to improve patient outcomes and reduce postoperative venous thromboembolism in arthroplasty patients.

RELEVANCE TO CLINICAL PRACTICE

This research demonstrates the capacity of nurses to lead the translation of evidence-based practice guidelines for prevention of venous thromboembolism into routine patient care.

The Effect of Age, Sex, Area Deprivation, and Living Arrangements on Total Knee Replacement Outcomes: A Study Involving the United Kingdom National Joint Registry Dataset

Background:

Total knee replacement (TKR) is a common procedure for the treatment of osteoarthritis that provides a substantial reduction of knee pain and improved function in most patients. We investigated whether sociodemographic factors could explain variations in the benefit resulting from TKR.

Methods:

Data were collected from 3 sources: the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man; National Health Service (NHS) England Patient Reported Outcome Measures; and Hospital Episode Statistics. These 3 sources were linked for analysis. Pain and function of the knee were measured with use of the Oxford Knee Score (OKS). The risk factors of interest were age group, sex, deprivation, and social support. The outcomes of interest were sociodemographic differences in preoperative scores, 6-month postoperative scores, and change in scores.

Results:

Ninety-one thousand nine hundred and thirty-six adults underwent primary TKR for the treatment of osteoarthritis in an NHS England unit from 2009 to 2012. Sixty-six thousand seven hundred and sixty-nine of those patients had complete knee score data and were included in the analyses for the present study. The preoperative knee scores were worst in female patients, younger patients, and patients from deprived areas. At 6 months postoperatively, the mean knee score had improved by 15.2 points. There were small sociodemographic differences in the benefit of surgery, with greater area deprivation (−0.71 per quintile of increase in deprivation; 95% confidence interval [CI], −0.76 to −0.66; p < 0.001) and younger age group (−3.51 for ≤50 years compared with 66 to 75 years; 95% CI, −4.00 to −3.02; p < 0.001) associated with less benefit. Cumulatively, sociodemographic factors explained <1% of the total variability in improvement.

Conclusions:

Sociodemographic factors have a small influence on the benefit resulting from TKR. However, as they are associated with the clinical threshold at which the procedure is performed, they do affect the eventual outcomes of TKR.

Level of Evidence:

Prognostic Level IV. See Instructions for Authors for a complete description of evidence.

Good results with minimally invasive unicompartmental knee resurfacing after 10-year follow-up

The current study was designed to determine (1) 10-year implant survival and (2) patient's self-reported functional outcome in a single surgeon's consecutive cohort of patients who had undergone minimally invasive unicondylar resurfacing with a modified cementation technique utilizing a cobalt-chromium femur/inlaid all-PE tibia, fixed-bearing unicompartmental prosthesis. We included 344 consecutive patients (361 knees) who had received the study device between January 2002 and December 2005 in this retrospective study. After 10 years, 78 patients (78 knees) had died, 59 (59 knees) were lost to follow-up and four (four knees) did not participate. Thirteen knees (11 patients) were revised after a mean of 5.8 ± 1.9 years. Hence, the study population at follow-up comprised 192 patients (207 knees). Ten-year implant survival was 94.6% (95% confidence interval, 90.9-96.8%). The Forgotten Joint Score and Oxford Knee Score were 68.9 ± 28.9 and 39 ± 9.1, respectively. Excellent survivorship and clinical outcomes were obtained with UKA with an inlaid all-PE tibia with a modified cementation technique.

Patient Satisfaction After Total Knee Arthroplasty: A Realistic or Imaginary Goal?

This article summarizes the current literature regarding patient satisfaction after total knee arthroplasty. In 10% to 15% of cases, the operation has not met the patients' expectations. The causes of this dissatisfaction are multifactorial, and include patient-related factors, details related to the surgical procedure and prosthesis chosen, perioperative factors, and factors associated with nursing and general medical care. However, surgeons must bear the brunt of patients' dissatisfaction. This dissatisfaction erodes the doctor-patient relationship, and may have implications in an emerging health care economy in which doctors and hospitals are reimbursed based on both clinical outcome and patient satisfaction.

Chondrogenesis of human bone marrow mesenchymal stem cells in 3-dimensional, photocrosslinked hydrogel constructs: Effect of cell seeding density and material stiffness

Three-dimensional hydrogel constructs incorporated with live stem cells that support chondrogenic differentiation and maintenance offer a promising regenerative route towards addressing the limited self-repair capabilities of articular cartilage. In particular, hydrogel scaffolds that augment chondrogenesis and recapitulate the native physical properties of cartilage, such as compressive strength, can potentially be applied in point-of-care procedures. We report here the synthesis of two new materials, [poly-l-lactic acid/polyethylene glycol/poly-l-lactic acid] (PLLA-PEG 1000) and [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid] (PDLLA-PEG 1000), that are biodegradable, biocompatible (>80% viability post fabrication), and possess high, physiologically relevant mechanical strength (∼1500 to 1800kPa). This study examined the effects of physiologically relevant cell densities (4, 8, 20, and 50×10⁶/mL) and hydrogel stiffnesses (∼150kPa to∼1500kPa Young's moduli) on chondrogenesis of human bone marrow stem cells incorporated in hydrogel constructs fabricated with these materials and a previously characterized PDLLA-PEG 4000. Results showed that 20×10⁶cells/mL, under a static culture condition, was the most efficient cell seeding density for extracellular matrix (ECM) production on the basis of hydroxyproline and glycosaminoglycan content. Interestingly, material stiffness did not significantly affect chondrogenesis, but rather material concentration was correlated to chondrogenesis with increasing levels at lower concentrations based on ECM production, chondrogenic gene expression, and histological analysis. These findings establish optimal cell densities for chondrogenesis within three-dimensional cell-incorporated hydrogels, inform hydrogel material development for cartilage tissue engineering, and demonstrate the efficacy and potential utility of PDLLA-PEG 1000 for point-of-care treatment of cartilage defects.

STATEMENT OF SIGNIFICANCE

Engineering cartilage with physiologically relevant mechanical properties for point-of-care applications represents a major challenge in orthopedics, given the generally low mechanical strengths of traditional hydrogels used in cartilage tissue engineering. In this study, we characterized a new material that possesses high mechanical strength similar to native cartilage, and determined the optimal cell density and scaffold stiffness to achieve the most efficient chondrogenic response from seeded human bone marrow stem cells. Results show robust chondrogenesis and strongly suggest the potential of this material to be applied clinically for point-of-care repair of cartilage defects.

Correlations between inflammatory cytokines, muscle damage markers and acute postoperative pain following primary total knee arthroplasty

BACKGROUND

Despite the success of total knee arthroplasty (TKA) in reducing knee pain and improving functional disability, the management of acute postoperative pain is still unsatisfactory. This study was aimed to quantitatively analyze the possible correlations between inflammatory cytokines, muscle damage markers and acute postoperative pain following primary TKA.

METHODS

Patients scheduled for unilateral primary TKA were consecutively included, the serial changes of the numerical rating scale (NRS) at rest (NRSR) and at walking (NRSW), serum inflammatory cytokines and muscle damage markers were assessed before surgery (T0) and at postoperative day 1, 2, 3 and 5 (T1-T4, respectively); while pain disability questionnaire (PDQ) and synovial fluid inflammatory cytokines were evaluated at T0. The correlations between inflammatory cytokines, muscle damage markers and pain scores were examined, and Bonferroni correction was applied for multiple comparisons.

RESULTS

Ninety six patients were included for serum markers and pain evaluations at T0-T4, while 54 (56.25%) for synovial fluid cytokines at T0. The NRSR at T1 and T2 were positively correlated with preoperative NRSW, while the NRSW at T1 to T4 were positively correlated with preoperative NRSR, NRSW and PDQ (all p < 0.05). The NRSR was positively correlated with serum PGE2, IL-6, and CK at T1; the NRSW was positively correlated with serum CRP at T1, with PGE2 and IL-6 at T1 to T3, with CK at T2 and T4, and with Mb and LDH at T1 to T4 (all p < 0.003). Meanwhile, positive correlations were observed between preoperative NRSW and synovial fluid PGE2, IL-6, IL-8, or TNF-α, as well as between PDQ and PGE2 (all p < 0.003), but no associations between postoperative pain scores and preoperative synovial fluid cytokines was found (all p ≥ 0.003). Additionally, the NRSR at T1 and T2, and NRSW at T1 to T4 were positively correlated with body mass index (all p < 0.05).

CONCLUSIONS

Serum inflammatory cytokines and muscle damage markers are positively correlated with acute postoperative pain following primary TKA, and the key cytokines (CRP, PGE2, and IL-6) and markers (Mb, CK and LDH) may serve as the targets for developing novel analgesic strategies.

Good Early Results Obtained with a Guided-Motion Implant for Total Knee Arthroplasty: A Consecutive Case Series

Background:

Previous studies have shown a high incidence of complications with a bi-cruciate stabilized (BCS) guided-motion total knee arthroplasty (TKA) design, which led to recent modifications of the design by the manufacturer.

Objective:

The current study was undertaken to assess whether the use of this TKA system with an extension-first surgical technique is associated with a similar rate of short-term adverse outcome as reported in literature.

Material and Methods:

This retrospective study enrolled 257 consecutive patients (257 knees) undergoing TKA for osteoarthritis of the knee, with the first 153 receiving cemented Journey BCS I implants and the remaining 104 receiving cemented Journey BCS II implants when these became available.

Results:

Mean follow-up time for the cohort was 24.5 ± 7.8 months (range, 12 - 36 months). There were no cases of stiffness. Incidence of iliotibial friction syndrome was considered low: three (2.0%) knees in the BCS I group and two (1.9%) in the BCS II group (p = 0.676). Five (2.5%) knees presented with mild instability in midflexion, three (2.0%) in the BCS I group and two (1.9%) in the BCS II group (p = 0.676). One patient with a BCS I implant required reoperation for aseptic loosening 23 months postoperatively. At one-year follow-up, there were no clinically relevant differences in any of the clinical outcomes.

Conclusion:

When used in combination with an extension-first surgical technique, good early functional results with an acceptable rate of complications were obtained with both the original and the updated Journey BCS knee implant.

Patients' expectations about total knee arthroplasty outcomes

OBJECTIVE

The aim of this study was to ascertain Patients' pre-operative expectations of total knee arthroplasty (TKA) recovery.

METHODS

Two hundred and thirty-six patients with knee osteoarthritis (OA) who underwent TKA completed self-administered questionnaires before their surgery. Patients' expectations of time to functional recovery were measured using an ordinal time-response scale to indicate expected time to recovery for each of 10 functional activities. Expected time to recovery was dichotomized into short- and long-term expectations for recovery of each activity using median responses. Knee pain and function were ascertained using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Other measures included the SF-36, the Depression, Anxiety and Stress Scale (DASS) and the Medical Outcomes Study Social Support Survey (MOS-SSS). Multivariate logistic regression was used to identify pre-operative characteristics associated with short- vs. long-term expectations.

RESULTS

Sixty-five percent of the patients were females and 70% Whites; mean age was 65 years. Patients were optimistic about their time to functional recovery: over 65% of patients expected functional recovery within 3 months. Over 80% of the patients expected to perform 8 of the 10 activities within 3 months. Patients who expected to be able to perform the functional activities in <6 weeks were more likely to be younger, male, and have lower self-reported pain and better general health before surgery compared to those who expected to be able to perform the activities 3 months post-surgery or later.

CONCLUSION

Pre-operative patient characteristics may be important to evaluate when considering individual Patients' expectations of post-operative outcomes.

Decreased Range of Motion After Total Knee Arthroplasty Is Predicted by the Tampa Scale of Kinesiophobia

BACKGROUND

Range of motion (ROM) is important for functional outcome after total knee arthroplasty (TKA); however, some patients hesitate to maximize their ROM postoperatively. The Tampa Scale of Kinesiophobia (TSK) measures patients' fear of movement. The primary purpose of this investigation was to determine whether TSK scores correlated with decreased ROM after primary TKA. A secondary purpose was to determine whether biofeedback could increase ROM after TKA.

METHODS

Patients were recruited from the senior author's practice between June 2011 and March 2013. A clinical photograph was taken of each patient's knee in maximum passive flexion in the operating room immediately following closure. Patients were randomized to the control or photograph group before incision. A linear mixed model was implemented to determine whether the TSK score and viewing the photo correlated to ROM.

RESULTS

Seventy-nine patients were analyzed for correlation between the TSK score and the knee ROM. Sixty patients were analyzed for correlation between viewing the clinical photograph and the knee ROM. The linear mixed model demonstrated a significant negative correlation between the TSK score and both active (β = -0.47, P < .01) and passive (β = -0.66, P < .001) knee flexions. There was a trend toward decreased knee flexion among patients shown their clinical photograph.

CONCLUSION

The TSK was developed as a tool to identify patients at risk for maladaptive responses to painful stimuli. Our data suggest that the TSK may help arthroplasty surgeons identify patients at risk for decreased ROM after TKA. Showing patients a clinical photograph failed to increase ROM after TKA.

Patients' perceptions of physical activity before and after joint replacement: a systematic review with meta-ethnographic analysis

BACKGROUND

It has been perceived that people following total hip arthroplasty (THA) or total knee arthroplasty (TKA) have the capability, with reduced pain, to increase their levels of physical activity.

OBJECTIVES

To determine the attitudes and perceptions of people awaiting or having undergone THA or TKA to physical activity post-arthroplasty and to identify potential facilitators or barriers to engage in active living and physical activity pursuits.

METHODS

Systematic review of published and unpublished databases was undertaken from their inception to November 2014. Studies exploring the attitudes and perceptions of people awaiting or having undergone THA or TKA to physical activity post-arthroplasty were included. Data were analysed through a meta-ethnography approach.

RESULTS

From 528 citations, 13 papers were eligible, sampling 282 people post-THA or TKA. The literature was judged moderate to high quality. Following THA and TKA, people either wished to return to their pre-pathology level of physical activity or simply be able to engage in less physically demanding activities that are meaningful to them and their lifestyles. Barriers to engaging in higher levels of physical activity were largely related to limited information, which culminated in fear surrounding 'doing the right thing' both for individual's recovery and the longevity of the joint replacement.

CONCLUSIONS

While many people post-THA or TKA wish to return to pre-pathological physical activity status, there is limited interest in actually undertaking greater levels of physical activity post-arthroplasty either for pleasure or health gains. Improvement in education and awareness of this may be key drivers to improve habitualisation of physical activity post-arthroplasty.

TRIAL REGISTRATION NUMBER

CRD42014014995.

Projection Stereolithographic Fabrication of Human Adipose Stem Cell-Incorporated Biodegradable Scaffolds for Cartilage Tissue Engineering

The poor self-healing ability of cartilage necessitates the development of methods for cartilage regeneration. Scaffold construction with live stem cell incorporation and subsequent differentiation presents a promising route. Projection stereolithography (PSL) offers high resolution and processing speed as well as the ability to fabricate scaffolds that precisely fit the anatomy of cartilage defects using medical imaging as the design template. We report here the use of a visible-light-based PSL (VL-PSL) system to encapsulate human adipose-derived stem cells (hASCs) into a biodegradable polymer [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid (PDLLA-PEG)]/hyaluronic acid (HA) matrix to produce live cell constructs with customized architectures. After fabrication, hASCs showed high viability (84%) and were uniformly distributed throughout the constructs, which possessed high mechanical properties with a compressive modulus of 780 kPa. The hASC-seeded constructs were then cultured in control or TGF-β3-containing chondrogenic medium for up to 28 days. In chondrogenic medium-treated group (TGF-β3 group), hASCs maintained 77% viability and expressed chondrogenic genes Sox9, collagen type II, and aggrecan at 11, 232, and 2.29 × 10(5) fold increases, respectively compared to levels at day 0 in non-chondrogenic medium. The TGF-β3 group also produced a collagen type II and glycosaminoglycan-rich extracellular matrix, detected by immunohistochemistry, Alcian blue staining, and Safranin O staining suggesting robust chondrogenesis within the scaffold. Without chondroinductive addition (Control group), cell viability decreased with time (65% at 28 days) and showed poor cartilage matrix deposition. After 28 days, mechanical strength of the TGF-β3 group remained high at 240 kPa. Thus, the PSL and PDLLA-PEG/HA-based fabrication method using adult stem cells is a promising approach in producing mechanically competent engineered cartilage for joint cartilage resurfacing.

Cost-effectiveness of unicondylar versus total knee arthroplasty: a Markov model analysis

BACKGROUND

Unicondylar knee arthroplasty (UKA) is believed to lead to less morbidity and enhanced functional outcomes when compared with total knee arthroplasty (TKA). Conversely, UKA is also associated with a higher revision risk than TKA. In order to further clarify the key differences between these separate procedures, the current study assessing the cost-effectiveness of UKA versus TKA was undertaken.

METHODS

A state-transition Markov model was developed to compare the cost-effectiveness of UKA versus TKA for unicondylar osteoarthritis using a Belgian payer's perspective. The model was designed to include the possibility of two revision procedures. Model estimates were obtained through literature review and revision rates were based on registry data. Threshold analysis and probabilistic sensitivity analysis were performed to assess the model's robustness.

RESULTS

UKA was associated with a cost reduction of €2,807 and a utility gain of 0.04 quality-adjusted life years in comparison with TKA. Analysis determined that the model is sensitive to clinical effectiveness, and that a marginal reduction in the clinical performance of UKA would lead to TKA being the more cost-effective solution.

CONCLUSION

UKA yields clear advantages in terms of costs and marginal advantages in terms of health effects, in comparison with TKA.