The purpose of this study is to investigate the three-dimensional (3D) kinematics of normal knees in deep knee-bending motions like squatting and kneeling. Material & Methods: We investigated the in vivo kinematics of 4 Japanese healthy male volunteers (8 normal knees in squatting, 7 normal knees in kneeling). Each sequential motion was performed under fluoroscopic surveillance in the sagittal plane. Femorotibial motion was analyzed using 2D/3D registration technique, which uses computer-assisted design (CAD) models to reproduce the spatial position of the femur and tibia from single-view fluoroscopic images. We evaluated the femoral rotation relative to the tibia and anteroposterior (AP) translation of the femoral sulcus and lateral epicondyle on the plane perpendicular to the tibial mechanical axis. Student's t test was used to analyze differences in the absolute value of axial rotation and AP translation of the femoral sulcus and lateral epicondyle during squatting and kneeling. Values of P < 0.05 were considered statistically significant. During squatting, knees were gradually flexed from −2.8 ± 1.3° to 145.5 ± 5.1° on average. Knees were gradually flexed from 100.8 ± 3.9° to 155.6 ± 3.2° on average during kneeling. Femurs during squatting displayed sharp external rotation relative to the tibia from 0° to 30° of flexion and it reached 12.5 ± 3.3° on average. From 30° to 130° of flexion, the femoral external rotation showed gradually, and it reached 19.1 ± 7.3° on average. From 130° to 140° of flexion, it was observed additionally, and reached 22.4 ± 6.1° on average. All kneeling knees displayed femoral external rotation relative to the tibia sharply from 100° to 150° of flexion, and it reached 20.7 ± 7.5° on average. From 100° to 120° of flexion, the femoral external rotation during squatting was larger than that during kneeling significantly. From 120° to 140° of flexion, there was no significant difference between squatting and kneeling. The sulcus during squatting moved 4.1 ± 4.8 mm anterior from 0° to 60° of flexion. From 60° of flexion it moved 13.6 ± 13.4 mm posterior. The sulcus during kneeling was not indicated significant movement with the knee flexion. The lateral epicondyle during squatting moved 39.4 ± 7.7 mm posterior from 0° to 140° of flexion. The lateral epicondyle during kneeling moved 22.0 ± 5.4 mm posterior movement from 100° to 150° of flexion. In AP translation of the sulcus from 100° to 140° of flexion, there was no significant difference between squatting and kneeling. However in that of the lateral epicondyle, squatting groups moved posterior significantly. Even if they were same deep knee-bending, the kinematics were different because of the differences of daily motions. The results in this study demonstrated that in vivo kinematics of deep knee-bending were different between squatting and kneeling

Summary Statement. Increased Dkk-1 signaling is associated with OA occurrence and joint microenvironment damage. Interruption of Dkk1 action is beneficial to improve OA knees. Introduction. Osteoarthritis (OA) is a leading cause of disability and healthcare financial burden for total knee arthroplasty, rehabilitation, and disability. Inappropriate mechanical stress, immunological, or biochemical regulation reportedly disturbs homeostasis among cartilage, synovium and subchondral bone microstructure that contributes to OA pathogenesis. Control of joint-deleterious factor action is an emerging strategy to ameliorate OA-induced joint deterioration. Dickkopf-1 (Dkk-1) is a potent inhibitor for Wnt/β-catenin signaling regulation of tissue development and remodeling in physiological or pathological contexts. Dkk-1 also acts as a master deleterious factor that represses osteoblast differentiation capacity and bone repair. Associations among Dkk-1 expression, chondrocyte fate, synovial fibroblast behavior or OA incidence are merit of characterization. Patients & Methods. Cartilage, synovial tissue and fluid were harvested from informed consent OA patients underwent arthroplasty and patient with knee injuries without OA changes as controls. Primary chondrocyte cultures and synovial fibroblasts were treated with inflammatory cytokines or Dkk-1 antisense oligonucleotide or monoclonal antibodies. Knees in experimental animals were subjected to anterior cruciate ligament transection- or intra-articular collagenase injection to induce OA. Joint inflammation, integrity and subchondral bone microstructure in knees as well gait profiles were quantified using 2-deoxyglucose-probed near-infrared in vivo image, µCT, catwalk and histomorphometric analyses. Results. In clinical vignettes, patients with end-stage OA knee had higher abundances of Dkk-1 in cartilage, synovial tissue, and synovial fluid compared to control patients. Disruption of DKk-1 signaling ameliorated the promoting effects of inflammatory cytokines on the survival and cartilage matrix synthesis in primary cartilage chondrocyte cultures. Of interest, Dkk-1 neutralization attenuated the excessive angiogenic activities and matrix metalloproteinase secretion in primary synovial fibroblasts of OA knees. Dkk-1 modulation of survival or metabolic activities in chondrocytes and synovial fibroblasts were through β-catenin-dependent and -independent signaling pathways. Moreover, increased Dkk-1 expression in lesion sites and sera was associated with the incidence of femoral head osteonecrosis. Loss of Dkk-1 action alleviated bone cell apoptosis in osteonecrotic bone microenvironments. In experimental OA knee models, knockdown of Dkk-1 alleviated articular cartilage damage as evidenced by improved Mankin score in OA knees. Dkk-1 disruption also alleviated the adverse effects of OA on subchondral bone exposure and loss of trabecular bone volume and mineral acquisition in injured joints. Loss of Dkk-1 function reduced joint inflammation, vessel number, leukocyte infiltration in synovium compartment of OA joint and improved gait profiles of affected limbs. Conclusion. Dkk-1 signaling is associated with the OA knee occurrence and accelerates apoptosis, matrix degradation and angiogenic activities in chondrocytes and synovial fibroblasts of OA joint. Dkk-1 interference alleviates the promoting effects of OA on cartilage, synovial and subchondral bone remodeling. Blocking the deleterious actions of Dkk-1 in joint microenvironment will be a prospective molecular regime beneficial for retarding excessive joint deterioration in OA knees

Abstract

Robotic assistance in knee arthroplasty has become increasingly popular due to improved accuracy of prosthetic implantation. However, literature on the mid-term outcomes is limited especially that of hand-held robotic-assisted devices. We present one of the longest follow-up series to date using this novel technology and discuss the learning curve for introducing robotic technology into our practice.

The purpose of this single-surgeon study is to evaluate the survival, patient-reported outcomes and learning curve for handheld boundary-controlled robotic-assisted unicompartmental knee arthroplasties (HBRUKAs) at our hospital.

This retrospective study evaluates 100 cases (94 Medial, 6 Lateral) performed by a single surgeon between October 2012 and July 2018. 52% were males, mean age was 64.5y (range 47.3y-85.2y) and mean BMI was 31.3 (range 21.8–43). Both inlay (40%) and onlay (60%) designs were implanted. Patients were followed up routinely at 1 and 5 years with Oxford Knee Scores (OKS) recorded. The learning curve was determined by tourniquet times.

At a mean follow-up of 4.3 years (range 1.6y–7.3y), survivorship was 97%. There were three revisions: One case of aseptic loosening (1.5y), one case of deep-infection (3.8y) and one case of contralateral compartment osteoarthritis progression (5y). Mean 5-year OKS was 39.8. A 14.3% reduction in mean tourniquet times between the first 25 cases (105.5minutes) and subsequent cases (90.4minutes) was seen.

This single-surgeon study showed good survivorship and patient-reported outcomes for HBRUKAs at our hospital. A learning curve of approximately 25 cases was shown, with significant decreases in tourniquet times with respect to increased surgeon experience.

INTRODUCTION

Osteoarthritis (OA) is a growing societal burden, due to the ageing population. Less invasive, less damaging, and cheaper methods for diagnosis are needed, and sound technology is an emerging tool in this field.

Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA.

We analysed the shape of 114 arthritic knees at the time of primary TKA using the pre- operative CT scans. The aspect ratio and trapezoidicity ratio were quantified, and the post- operative prosthetic overhang was calculated. We compared the morphological characteristics with those of 12 TKA models.

There was significant variation in both the aspect ratio and trapezoidicity ratio between individuals. Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. Overhang was correlated with the aspect ratio (with a greater chance of overhang in narrow femurs), trapezoidicity ratio (with a greater chance in trapezoidal femurs), and the tibio- femoral angle (with a greater chance in valgus knees).

This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/ rectangular shape of the native femur.

There are few studies that have compared between continuous flexion activities and extension activities of normal knees. The purpose of this study is to compare in vivo kinematic comparison of normal knees between flexion activities and extension activities. Total of 8 normal male knees were investigated. We evaluated in vivo three-dimensional kinematics using 2D/3D registration technique. We compared femoral rotation angle relative to tibia, anterior/posterior (AP) translation of medial femoral sulcus (medial side) and lateral femoral epicondyle (lateral side) onto tibial plane perpendicular to tibial functional axis between flexion activities (F groups) and extension activities (E groups). Femoral external rotation was observed with the knee bending during both groups. The external rotation angle of F group was larger than that of E group significantly from 20 to 30 degrees with flexion (p < 0.05). Regarding medial side, anterior translation was observed up to 40 degrees in F group. From 40 to 140 degrees, posterior translation was observed. In E group, anterior translation was observed from 140 to 40 degrees with extension. From 40 degrees, posterior translation was observed. From 30 to 40 degrees, F group located anterior than E group (p < 0.05). Regarding lateral side, posterior translation was observed with flexion in F group. On the other hand, anterior translation was observed with extension in E group. Regarding AP location with flexion angle, there was no significant difference between two groups. In conclusion, there were different kinematics between flexion activities and extension activities.

Background

Surgical wound closure is not the surgeon”s favorite part of the total knee arthroplasty (TKA) surgery however it has vital rule in the success of surgery. Knee arthoplasty wounds are known to be more prone to infection, breakdown or delayed healing compared to hip arthroplasty wounds, and this might be explained by the increased tensile force applied on the wound with knee movement. This effect is magnified by the enhanced recovery protocols which aim to obtain high early range of movement. Most of the literature concluded that there is no difference between different closure methods

Purpose

Injuries of the meniscal attachments can lead to meniscal extrusion. We hypothesized that the extent of lateral meniscal extrusion (LME) was associated with the severity of the lateral meniscus posterior root tear (LMPRT). This study aimed to evaluate the relationship between preoperative LME and arthroscopic findings of LMPRT in knees with anterior cruciate ligament (ACL) injury.

There are many factors which contribute to function after TKA. In this study we focus on the effect of varus-valgus (VV) balancing measured externally. A loose knee can show instability (Sharkey 2014) while too tight, flexion can be limited. Equal lateral-medial balancing at surgery leads to a better result (Unitt 2008; Gustke 2014), which is generally the surgical goal. Indeed similar varus and valgus laxity angles have been found in most studies in vitro (Markolf 2015; Boguszewski 2015) and in vivo (Schultz 2007; Clarke 2016; Heesterbeek 2008). The angular ranges have been 3–5 degrees at 10–15 Nm of knee moment, females having the higher angles. The goal of this study was to measure the varus and valgus laxity, as well as the functional outcome scores, of two cohorts; well-functioning total knees after at least one year follow-up, and subjects with healthy knees in a similar age group to the TKR's. Our hypothesis was that the results will be equal in the two groups.

50 normal subjects average age 66 (27 male, 23 female) and 50 TKA at 1 year follow-up minimum average age 68 years (16 male, 34 female) were recruited in this IRB study. The TKA's were performed by one surgeon (PAM) of one TKA design, balancing by gap equalization. Subjects completed a KSS evaluation form to determine functional, objective, and satisfaction scores. Varus and valgus measurements were made using the Smart Knee Fixture (Borukhov 2016) at 20 deg flexion with a moment of 10 Nm.

The statistical results demonstrated that there was no significant difference in either varus or valgus laxity between the two groups (p= 0.9, 0.3 respectively). Pearson's correlation coefficient between varus and valgus laxity of the healthy group was 0.42, while for the TKA group was 0.55. In both cohorts varus laxity was significant higher than valgus laxity (p= 0.001^e−5 for healthy subjects and p=0.0001 for TKA). The healthy group had higher functional and objective KSS scores (p= 0.005^e−4, and p=0.004^e−5 respectively), but the same satisfaction scores as the TKA (p=0.3). No correlation was found between the total laxity of the TKA group and the KSS scores (functional, objective and satisfaction). Total laxity in females was significantly higher than in males in the healthy group, but no differences was found in the TKA group.

The hypothesis of equal varus and valgus angles in the 2 groups was supported. The larger varus angle implied a less stiff lateral collateral compared with the medial collateral. If the TKA's were balanced equally at surgery, it is possible there was ligament remodeling over time. However the functional scores were inferior for the TKA compared with normal. This finding has not been highlighted in the literature so far. The causes could include weak musculature (Yoshida 2013), non-physiologic kinematics due to the TKA design, or the use of rigid materials in the TKA. The result presents a challenge to improve outcomes after TKA.

Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with OA. In spite of extensive research into the consequences of malalignment, there is a lack of data regarding the potential variation between supine and standing (functional) conditions. The purpose of this study was to explore this relationship in asymptomatic, osteoarthritic and prosthetic knees. Our hypothesis was that the change in alignment of these three groups would be different.

Infrared position capture was used to assess knee alignment for 30 asymptomatic controls and 31 patients with OA, before and after TKA. Coronal and sagittal mechanical femorotibial (MFT) angles in extension (negative values varus/hyperextension) were measured supine and in bi-pedal stance and changes analysed using a paired t-test. To quantify this change in 3D, vector plots of ankle centre displacement relative to the knee centre were produced.

Alignment in both planes changed significantly from supine to standing for all three groups, most frequently towards relative varus and extension. In the coronal plane, the mean±SD(°) of the supine/standing MFT angles was 0.1±2.5/−1.1±3.7 for asymptomatic (p=0.001), −2.5±5.7/−3.6±6.0 for osteoarthritic (p=0.009) and −0.7±1.4/ −2.5±2.0 for prosthetic knees (p<0.001). In the sagittal plane, the mean±SD(°) of the supine/standing MFT angles was −1.7±3.3/−5.5±4.9 for asymptomatic (p<0.001), 7.7±7.1/1.8±7.7 for osteoarthritic (p<0.001) and 6.8±5.1/1.4±7.6 for prosthetic knees (p<0.001). The vector plots showed that the trend of relative varus and extension in stance was similar in overall magnitude and direction between the groups.

The similarities between each group did not support our hypothesis. The consistent kinematic pattern for different knee types suggests that soft tissue restraints rather than underlying joint deformity may be more influential in dynamic control of alignment from lying to standing. This potential change should be considered when positioning TKA components on supine limbs as post-operative functional alignment may be different.

Subchondral bone deterioration and osteophyte formation attributable to excessive mineralization are prominent features in the progression of end-stage knee osteoarthritis (OA). The cellular events underlying subchondral bone integrity diminishment remained elusive. This study was undertaken to characterize behavior and intracellular signaling of subchondral mesenchymal stem cells (SMSCs) and bone-marrow MSCs (BMMSCs) in OA knees isolated from patients with end-stage knee OA underwent total knee arthroplasty. The SMSCs isolated from subchondral bone explants expressed remarkable surface antigens CD73, CD105, CD90, CD166, CD44, CD29, instead of MHC II, CD45, and CD31. The cell cultures exhibited high proliferation capacity concomitant with low population doubling time compared to those of BMMSCs. Incubation in differentiation media, the SMSCs showed high osteogenic and chondrogenic lineage commitment and low adipogenic differentiation potential. They also exhibited high expression of embryonic stem cell marker OCT3/4, osteogenic factors Wnt3a, β-catenin and microRNA-29a (miR-29a) in conjunction with low expression of joint-deleterious factors HDAC4, TGF-β1, IL-1β, TNFα, and MMP3. Loss of miR-29a function lowered HDAC4 level, mineralized matrix accumulation and osteogenic marker expression of SMSCs. miR-29a reduced HDAC4 translation through targeting the 3”-untranslated region of HDAC4, which concomitantly sustained Wnt3a and β-catenin signaling. Collectively, high osteogenic lineage commitment existed in the SMSCs in OA knee microenvironment. miR-29a modulation of HDAC4 and Wnt3a signaling contributed to the increases in osteogenesis. This study shines a light no the biological role of MSCs in subchondral compartment in the end-stage OA development and highlights a new source of MSCs for joint tissue repair.

For degenerative osteoarthritis of the knees, a variety of non-surgical management options have been tried from time to time. Medical management, chondroprotective agents, disease modifying drugs, viscosupplimentation etc. to name a few. Arthroscopic knee lavage with saline also has shown good results, with the effect of cleaning the debries from the joint.

Growth Factors Rich Plasma (GFRP) or Platelet Rich Plasma (PRP) is an emerging treatment therapy called “ Orthobiologics”. Alfa granules in platelets contain numerous growth factors which enhance tissue recovery dramatically by catalyzing the body's natural healing response. PRP also attracts Mesenchymal Stem Cells, which differentiate into variety of cell types during tissue repair processes & induce the production of new collagen by the fibroblasts, osteoblasts and chondrocytes as per the need of the parent tissue.

Knee lavage is done under local anesthesia using single antero-lateral portal. Four liters of saline is used to lavage the knee and at the end of procedure 80 mg. methyl prednisolone is injected. For GFRP injection, 100 cc of patient's blood is double centrifuged in the refrigerated blood component separator centrifuge in the blood bank giving about 15 cc of buffy layer having GFRP.

Since Feb. 2010, more than 1000 knees of different grades of osteoarthritis have been injected with GFRP and the results compared with other different treatment options. Results of few different combination therapies are presented in this study. 1. Knee Lavage Vs Autologous GFRP Injection (100+100 cases) 2. Knee Lavage + Autologous GFRP Injection in 1 knee Vs GFRP Injection only in other knee (200+200 Knees) 3. Visco-supplimentation Vs Autologous GFRP Injection. (10+10cases)

Results were analyzed up to 1 year as per VAS scale. Knee Lavage clears the joint of the microscopic and macroscopic debris of the cartilage and synovium which are causing chemical and mechanical irritation resulting in the inflammatory cascade. GFRP injection tries to repair the cartilage by the efficacy of the Growth factors contained therein. It has been observed that Knee Lavage and GFRP Injection have almost similar efficacy at 1 year, though knee lavage starts showing its effects early. GFRP therapy has shown better results compared to visco supplimentation at 1 year. Combination of knee lavage with GFRP injection showed much better results than GFRP injection alone and the results are inversely related to the grade of the osteoarthritis. Viscosupplimentation has very short lived efficacy.

It's concluded that Knee Lavage followed by GFRP injection gives the best long term results and this pilot project initiated, hopefully will go a long way in future to change the course of the management for osteoarthritis knees at a minimal cost and may obviate the need for Knee arthroplasty if started in early stages of Osteoartrhritis.