Gene Expression Signatures of Synovial Fluid Multipotent Stromal Cells in Advanced Knee Osteoarthritis and Following Knee Joint Distraction

Mechanical loading and orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA): a comprehensive review

The importance of mechanical loading and its relationship to orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA) is beginning to receive attention. This review explores the current efficacy of orthobiologic interventions, notably platelet-rich plasma (PRP), bone marrow aspirate (BMA), and mesenchymal stem/stromal cells (MSCs), in combating PTOA drawing from a comprehensive review of both preclinical animal models and human clinical studies. This review suggests why mechanical joint loading, such as running, might improve outcomes in PTOA management in conjunction with orthiobiologic administration. Accumulating evidence underscores the influence of mechanical loading on chondrocyte behavior and its pivotal role in PTOA pathogenesis. Dynamic loading has been identified as a key factor for optimal articular cartilage (AC) health and function, offering the potential to slow down or even reverse PTOA progression. We hypothesize that integrating the activation of mechanotransduction pathways with orthobiologic treatment strategies may hold a key to mitigating or even preventing PTOA development. Specific loading patterns incorporating exercise and physical activity for optimal joint health remain to be defined, particularly in the clinical setting following joint trauma.

In Vitro Osteogenesis Study of Shell Nacre Cement with Older and Young Donor Bone Marrow Mesenchymal Stem/Stromal Cells

Bone void-filling cements are one of the preferred materials for managing irregular bone voids, particularly in the geriatric population who undergo many orthopedic surgeries. However, bone marrow mesenchymal stem/stromal cells (BM-MSCs) of older-age donors often exhibit reduced osteogenic capacity. Hence, it is crucial to evaluate candidate bone substitute materials with BM-MSCs from the geriatric population to determine the true osteogenic potential, thus simulating the clinical situation. With this concept, we investigated the osteogenic potential of shell nacre cement (SNC), a bone void-filling cement based on shell nacre powder and ladder-structured siloxane methacrylate, using older donor BM-MSCs (age > 55 years) and young donor BM-MSCs (age < 30 years). Direct and indirect cytotoxicity studies conducted with human BM-MSCs confirmed the non-cytotoxic nature of SNC. The standard colony-forming unit-fibroblast (CFU-F) assay and population doubling (PD) time assays revealed a significant reduction in the proliferation potential (p < 0.0001, p < 0.05) in older donor BM-MSCs compared to young donor BM-MSCs. Correspondingly, older donor BM-MSCs contained higher proportions of senescent, β-galactosidase (SA-β gal)-positive cells (nearly 2-fold, p < 0.001). In contrast, the proliferation capacity of older donor BM-MSCs, measured as the area density of CellTrackerTM green positive cells, was similar to that of young donor BM-MSCs following a 7-day culture on SNC. Furthermore, after 14 days of osteoinduction on SNC, scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) showed that the amount of calcium and phosphorus deposited by young and older donor BM-MSCs on SNC was comparable. A similar trend was observed in the expression of the osteogenesis-related genes BMP2, RUNX2, ALP, COL1A1, OMD and SPARC. Overall, the results of this study indicated that SNC would be a promising candidate for managing bone voids in all age groups.

Harnessing joint distraction for the treatment of osteoarthritis: a bibliometric and visualized analysis

Osteoarthritis (OA) stands as a prevalent degenerative joint ailment, demanding immediate attention towards the development of efficacious therapeutic interventions. Presently, a definitive cure for OA remains elusive, and when conservative treatment modalities prove ineffective, resorting to a joint prosthesis becomes imperative. Temporary distraction emerges as a pivotal joint-preserving intervention in human OA patients, conferring both clinical amelioration and structural enhancements. Although extant clinical investigations exist, they are characterized by relatively modest sample sizes. Nonetheless, these studies furnish compelling evidence affirming that joint distraction engenders sustained clinical amelioration and structural refinement. Despite substantial strides in the last decade, a bibliometric analysis of joint distraction within the realm of osteoarthritis treatment research has been conspicuously absent. In this context, we have undertaken a comparative investigation utilizing bibliometric methodologies to scrutinize the landscape of joint distraction within osteoarthritis treatment. Our comprehensive analysis encompassed 469 scholarly articles. Our findings evince a consistent escalation in global research interest and publication output pertaining to this subject. The United States emerged as the frontrunner in international collaboration, publication count, and citation frequency, underscoring its preeminence in this domain. The journal "Osteoarthritis and Cartilage" emerged as the principal platform for disseminating research output on this subject. Notably, Mastbergen SC emerged as the most prolific contributor in terms of authorship. The identified keywords predominantly revolved around non-surgical interventions and joint arthroscopy procedures. This bibliometric analysis, augmented by visual representations, furnishes invaluable insights into the evolutionary trajectory of joint distraction as an osteoarthritis treatment modality spanning from 2003 to 2023. These insights will serve as a compass for the scientific community, facilitating further exploration in this promising domain.

Mesenchymal stem cells in synovial fluid increase in number in response to synovitis and display more tissue-reparative phenotypes in osteoarthritis

BACKGROUND

Synovial fluid mesenchymal stem cells (SF-MSCs) originate in the synovium and contribute to the endogenous repair of damaged intra-articular tissues. Here, we clarified the relationship between their numbers and joint structural changes during osteoarthritis (OA) progression and investigated whether SF-MSCs had phenotypes favorable for tissue repair, even in an OA environment.

METHODS

Partial medial meniscectomy (pMx) and sham surgery were performed on both knees of rats. SF and knee joints were collected from intact rats and from rats at 2, 4, and 6 weeks after surgery. SF was cultured for 1 week to calculate the numbers of colony-forming cells and colony areas. Joint structural changes were evaluated histologically to investigate their correlation with the numbers and areas of colonies. RNA sequencing was performed for SF-MSCs from intact knees and knees 4 weeks after the pMx and sham surgery.

RESULTS

Colony-forming cell numbers and colony areas were greater in the pMx group than in the intact and sham groups and peaked at 2 and 4 weeks, respectively. Synovitis scores showed the strongest correlation with colony numbers (R = 0.583) and areas (R = 0.456). RNA sequencing revealed higher expression of genes related to extracellular matrix binding, TGF-β signaling, and superoxide dismutase activity in SF-MSCs in the pMx group than in the sham group.

CONCLUSION

The number of SF-MSCs was most closely correlated with the severity of synovitis in this rat OA model. Tissue-reparative gene expression patterns were observed in SF-MSCs from OA knees, but not from knees without intra-articular tissue damage.

Gremlin-1 promotes IL-1β-stimulated chondrocyte inflammation and extracellular matrix degradation via activation of the MAPK signaling pathway

The role and mechanism of Gremlin-1 in osteoarthritis (OA) were expected to be probed in this study. Firstly, an in vitro OA model was constructed by stimulating human chondrocyte cell line CHON-001 with IL-1β. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were utilized for assessing the effect of IL-1β with different concentrations (5, 10, and 20 ng/mL) on the activity and Gremlin-1 messenger RNA of CHON-001 cells, respectively. Besides, the influence of knocking down/over-expressing Gremlin-1 on the inflammatory factors (IL-6, TNF-α, IL-18 and PGE2), oxidative stress-related substances (malondialdehyde [MDA]; superoxide dismutase [SOD]; lactate dehydrogenase [LDH]), extracellular matrix (ECM) degradation-related proteins, and mitogen-activated protein kinase (MAPK) pathway proteins in IL-1β-stimulated CHON-001 cells were tested by enzyme-linked immunosorbent assay, related kits, qRT-PCR, and western blot, respectively. IL-1β inhibited CHON-001 cell proliferation and upregulated Gremlin-1 expression in a concentration-dependent manner. Overexpression of Gremlin-1 increased the IL-6, TNF-α, IL-18, PGE2, and MDA levels, enhanced the LDH activity, and decreased the SOD activity in IL-1β-induced CHON-001 cells; while the effect of Gremlin-1 knockdown on the above factors was in contrast with that of the overexpression. Furthermore, overexpression of Gremlin-1 upregulated protein expression of matrix metalloproteinase (MMP)-3, MMP-13, and ADAMTS4 while downregulated protein expression of collagen III, aggrecan, and SOX-9 in IL-1β-stimulated CHON-001 cells. Besides, overexpression of Gremlin-1 increased the p-p38/p38 value while decreased the p-JNK/JNK value in L-1β-stimulated CHON-001 cells; however, knockdown of Gremlin-1 reversed the above results. Gremlin-1 may promote IL-1β-stimulated CHON-001 cell inflammation and ECM degradation by activating the MAPK signaling pathway.

Effect of Combined Intraosseous and Intraarticular Infiltrations of Autologous Platelet-Rich Plasma on Subchondral Bone Marrow Mesenchymal Stromal Cells from Patients with Hip Osteoarthritis

Osteoarthritis (OA) is a debilitating condition that significantly impacts its patients and is closely associated with advancing age and senescence. Treatment with autologous platelet rich plasma (PRP) is a novel approach that is increasingly being researched for its effects. Subchondral bone mesenchymal stromal cells (MSCs) are key progenitors that form bone and cartilage lineages that are affected in OA. This study investigated the changes in subchondral bone MSCs before and after combined intraosseous (IO) and intraarticular (IA) PRP infiltration. Patient bone marrow aspirates were collected from 12 patients (four male, eight female) aged 40–86 years old (median 59.5). MSCs were expanded in standard media containing human serum to passage 1 and analysed for their colony-forming potential, senescence status, and gene expression. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) at baseline and 6 months post second infiltration were used to assess the clinical outcomes; seven patients were considered responders and five non-responders. The number of colony-forming MSCs did not increase in the post treatment group, however, they demonstrated significantly higher colony areas (14.5% higher compared to Pre) indicative of enhanced proliferative capacity, especially in older donors (28.2% higher). Senescence assays also suggest that older patients and responders had a higher resistance to senescent cell accumulation. Responder and non-responder MSCs tended to differ in the expression of genes associated with bone formation and cartilage turnover including osteoblast markers, matrix metalloproteinases, and their inhibitors. Taken together, our data show that in hip OA patients, combined IO and IA PRP infiltrations enhanced subchondral MSC proliferative and stress-resistance capacities, particularly in older patients. Future investigation of the potential anti-ageing effect of PRP infiltrations and the use of next-generation sequencing would contribute towards better understanding of the molecular mechanisms associated with OA in MSCs.

Subchondral bone changes after joint distraction treatment for end stage knee osteoarthritis

OBJECTIVE

Increased subchondral cortical bone plate thickness and trabecular bone density are characteristic of knee osteoarthritis (OA). Knee joint distraction (KJD) is a joint-preserving knee OA treatment where the joint is temporarily unloaded. It has previously shown clinical improvement and cartilage regeneration, indicating reversal of OA-related changes. The purpose of this research was to explore 3D subchondral bone changes after KJD treatment using CT imaging.

DESIGN

Twenty patients were treated with KJD and included to undergo knee CT imaging before, one, and two years after treatment. Tibia and femur segmentation and registration to canonical surfaces were performed semi-automatically. Cortical bone thickness and trabecular bone density were determined using an automated algorithm. Statistical parametric mapping (SPM) with two-tailed F-tests was used to analyze whole-joint changes.

RESULTS

Data was available of 16 patients. Subchondral cortical bone plate thickness and trabecular bone density were higher in the weight-bearing region of the most affected compartment (MAC; mostly medial). Especially the MAC showed a decrease in thickness and density in the first year after treatment, which was sustained towards the second year.

CONCLUSIONS

KJD treatment results in bone changes that include thinning of the subchondral cortical bone plate and decrease of subchondral trabecular bone density in the first two years after treatment, potentially indicating a partial normalization of subchondral bone.

Attenuation of osteoarthritis progression through intra-articular injection of a combination of synovial membrane-derived MSCs (SMMSCs), platelet-rich plasma (PRP) and conditioned medium (secretome)

PURPOSE

Osteoarthritis (OA) as a progressive destructive disease of articular cartilage is the most common joint disease characterized by reduction of joint cartilage thickness, demolition of cartilage surface and new bone formation. To overcome these problems, the purpose of the current research was to evaluate and compare the in vivo effects of synovial membrane-derived mesenchymal stem cell (SMMSCs), platelet-rich plasma (PRP) and conditioned medium (secretome) on collagenase II-induced rat knee osteoarthritis (KOA) remedy.

METHODS

For the first step, SMMSCs were isolated and characterized. Also, secretome was collected from SMMSCs culture. Furthermore, PRP was collect from the rat heart venous blood. Second, two injection of collagenase II with an interval of 3 days was performed in the knee intra-articular space to induce osteoarthritis. Two weeks later, animals were randomly divided into 6 groups. Control group without treatment, positive group: taken an intra-articular sodium hyaluronate injection (0.1 ml), treatment groups taken an intra-articular injection of; treatment 1: SMMSCs (5 × 10⁶), treatment 2: SMMSCs (5 × 10⁶)/secretome (50 µl), treatment 3: SMMSCs (5 × 10⁶)/PRP (50 µl), and treatment 4: SMMSCs (5 × 10⁶)/ secretome (50 µl)/ PRP (50 µl). Three months later, rats were killed and the following assessments were executed: radiography, histopathology, and immunohistochemistry.

RESULTS

Our findings represented that a combination of the SMMSCs/secretome/PRP had a considerable effect on glycosaminoglycans (GAGs) and collagen II contents, articular cartilage preservation, compared with other groups. In addition, combination of the SMMSCs with PRP and secretome showed the lowest expression of mmp3, while SOX9 had the highest expression in comparison with other groups. Also, SMMSCs-injected groups demonstrated better results compared with positive and control groups.

CONCLUSIONS

Injecting a combination of the SMMSCs/secretome/PRP resulted in better efficacy in terms of joint space width, articular cartilage surface continuity and integrity, sub-chondral bone and ECM constituents such as collagen II. Indeed, transplantation of this combination could be considered as a preliminary therapy for clinical trial study in the future.

Joint distraction for osteoarthritis: clinical evidence and molecular mechanisms

Joint distraction, the prolonged mechanical separation of the bones at a joint, has emerged as a joint-preserving treatment for end-stage osteoarthritis, with the gradually growing promise of implementation in regular clinical practice. Joint distraction of the knee has been most extensively studied, with these studies showing prolonged symptomatic improvement in combination with repair of cartilage tissue in degenerated knee joints, supporting the concept that cartilage repair can translate into real clinical benefit. The reversal of tissue degeneration observed with joint distraction could be the result of one or a combination of various proposed mechanisms, including partial unloading, synovial fluid pressure oscillation, mechanical and biochemical changes in subchondral bone, adhesion and chondrogenic commitment of joint-derived mesenchymal stem cells or a change in the molecular milieu of the joint. The overall picture that emerges from the combined evidence is relevant for future research and treatment-related improvements of joint distraction and for translation of the insights gained about tissue repair to other joint-preserving techniques. It remains to be elucidated whether optimizing the biomechanical conditions during joint distraction can actually cure osteoarthritis rather than only providing temporary symptomatic relief, but even temporary relief might be relevant for society and patients, as it will delay joint replacement with a prosthesis at an early age and thereby avert revision surgery later in life. Most importantly, improved insights into the underlying mechanisms of joint repair might provide new leads for more targeted treatment options.

Device-Based Enrichment of Knee Joint Synovial Cells to Drive MSC Chondrogenesis Without Prior Culture Expansion In Vitro: A Step Closer to 1-Stage Orthopaedic Procedures

BACKGROUND

Synovial fluid (SF) mesenchymal stem cells (MSCs) are derived from the synovial membrane and have cartilage repair potential. Their current use in clinical practice is largely exploratory. As their numbers tend to be small, therapeutic procedures using MSCs typically require culture expansion. Previous reports indicate that the stem cell-mobilizing device (STEM device) intraoperatively increases SF-MSCs.

PURPOSE

This study evaluated the chondrogenic potential of non-culture expanded synovium-mobilized MSCs and SF-microfragments obtained after enrichment using the STEM device and ascertained if device-mediated synovial membrane manipulation facilitated ongoing MSC release.

STUDY DESIGN

Controlled laboratory study.

METHODS

Two samples of aspiration fluid were collected intraoperatively before and after STEM device utilization from patients (n = 16) undergoing diagnostic or therapeutic knee arthroscopy. Human knee synovium (n = 5) was collected during total knee replacement, and a suspended culture was performed to assess the effect of the STEM device on ongoing MSC release. Colony forming unit-fibroblastic assays were used to determine the number of MSCs. Additionally, cytometric characterization of stromal and immune cells and chondrogenesis differentiation assay were performed without culture expansion. Filtered platelet concentrates were prepared using the HemaTrate system.

RESULTS

After STEM device use, a significant increase was evident in SF-MSCs (P = .03) and synovial fluid-resident synovial tissue microfragments (P = .03). In vitro-suspended synovium released significantly more MSCs following STEM device use than nonstimulated synovium (P = .01). The STEM device-released total cellular fraction produced greater in vitro chondrogenesis with significantly more glycosaminoglycans (GAGs; P < .0001) when compared with non-STEM device synovial fluid material. Nonexpanded SF-MSCs and SF-microfragments combined with autologous filtered platelet concentrate produced significantly more GAGs than the complete chondrogenic media (P < .0001). The STEM device-mobilized cells contained more M2 macrophage cells and fewer M1 cells.

CONCLUSION

Non-culture expanded SF-MSCs and SF-microfragments had the potential to undergo chondrogenesis without culture expansion, which can be augmented using the STEM device with increased MSC release from manipulated synovium for several days. Although preliminary, these findings offer proof of concept toward manipulation of the knee joint environment to facilitate endogenous repair responses.

CLINICAL RELEVANCE

Although numbers were small, this study highlights 3 factors relevant to 1-stage joint repair using the STEM device: increased SF-MSCs and SF-microfragments and prolonged synovial release of MSCs. Joint repair strategies involving endogenous MSCs for cartilage repair without the need for culture expansion in a 1-stage procedure may be possible.

Evaluation of Human Bone Marrow Mesenchymal Stromal Cell (MSC) Functions on a Biomorphic Rattan-Wood-Derived Scaffold: A Comparison between Cultured and Uncultured MSCs

The reconstruction of large bone defects requires the use of biocompatible osteoconductive scaffolds. These scaffolds are often loaded with the patient’s own bone marrow (BM) cells to facilitate osteoinductivity and biological potency. Scaffolds that are naturally sourced and fabricated through biomorphic transitions of rattan wood (B-HA scaffolds) offer a unique advantage of higher mechanical strength and bioactivity. In this study, we investigated the ability of a biomorphic B-HA scaffold (B-HA) to support the attachment, survival and gene expression profile of human uncultured BM-derived mesenchymal stromal cells (BMSCs, n = 6) and culture expanded MSCs (cMSCs, n = 7) in comparison to a sintered, porous HA scaffold (S-HA). B-HA scaffolds supported BMSC attachment (average 98%) and their survival up to 4 weeks in culture. Flow cytometry confirmed the phenotype of cMSCs on the scaffolds. Gene expression indicated clear segregation between cMSCs and BMSCs with MSC osteogenesis- and adipogenesis-related genes including RUNX2, PPARγ, ALP and FABP4 being higher expressed in BMSCs. These data indicated a unique transcriptional signature of BMSCs that was distinct from that of cMSCs regardless of the type of scaffold or time in culture. There was no statistical difference in the expression of osteogenic genes in BMSCs or cMSCs in B-HA compared to S-HA. VEGF release from cMSCs co-cultured with human endothelial cells (n = 4) on B-HA scaffolds suggested significantly higher supernatant concentration with endothelial cells on day 14. This indicated a potential mechanism for providing vasculature to the repair area when such scaffolds are used for treating large bone defects.

Enhanced Extracellular Matrix Breakdown Characterizes the Early Distraction Phase of Canine Knee Joint Distraction

OBJECTIVE

Joint distraction triggers intrinsic cartilage repair in animal models of osteoarthritis (OA), corroborating observations in human OA patients treated with joint distraction. The present study explores the still largely elusive mechanism initiating this repair process.

DESIGN

Unilateral OA was induced in the knee joint of 8 dogs using the groove model; the contralateral joint served as a control. After 10 weeks, 4 animals received joint distraction, the other 4 serving as OA controls. Halfway the distraction period (after 4 weeks of a standard 8-week distraction treatment), all animals were euthanized, and joint tissues were collected. A targeted quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis was performed of commonly involved processes including matrix catabolism/anabolism, inflammation, and known signaling pathways in OA. In addition, cartilage changes were determined on tissue sections using the canine OARSI (Osteoarthritis Research Society International) histopathology score and collagen type II (COL2A1) immunostaining.

RESULTS

Midway distraction, the distracted OA joint showed an upregulation of proteolytic genes, for example, ADAMTS5, MMP9, MMP13, compared to OA alone and the healthy joints, which correlated with an increased OARSI score. Additionally, genes of the transforming growth factor (TGF)-β and Notch pathway, and markers associated with progenitor cells were increased.

CONCLUSIONS

Joint distraction initiates both catabolic and anabolic transcriptional responses. The enhanced turnover, and thereby renewal of the matrix, could be the key to the cartilage repair observed in the months after joint distraction.

Prediction of the Effect of the Osteoarthritic Joint Microenvironment on Cartilage Repair

Osteoarthritis (OA) is characterized by progressive articular cartilage loss. Human mesenchymal stromal cells (MSCs) can be used for cartilage repair therapies based on their potential to differentiate into chondrocytes. However, the joint microenvironment is a major determinant of the success of MSC-based cartilage formation. Currently, there is no tool that is able to predict the effect of a patient's OA joint microenvironment on MSC-based cartilage formation. Our goal was to develop a molecular tool that can predict this effect before the start of cartilage repair therapies. Six different promoter reporters (hIL6, hIL8, hADAMTS5, hWISP1, hMMP13, and hADAM28) were generated and evaluated in an immortalized human articular chondrocyte for their responsiveness to an osteoarthritic microenvironment by stimulation with OA synovium-conditioned medium (OAs-cm) obtained from 32 different knee OA patients. To study the effect of this OA microenvironment on MSC-based cartilage formation, MSCs were cultured in a three-dimensional pellet culture model, while stimulated with OAs-cm. Cartilage formation was assessed histologically and by quantifying sulfated glycosaminoglycan (sGAG) production. We confirmed that OAs-cm of different patients had significantly different effects on sGAG production. In addition, significant correlations were obtained between the effect of the OAs-cm on cartilage formation and promoter reporter outcome. Furthermore, we validated the predictive value of measuring two promoter reporters with an independent cohort of OAs-cm and the effect of 87.5% of the OAs-cm on MSC-based cartilage formation could be predicted. Together, we developed a novel tool to predict the effect of the OA joint microenvironment on MSC-based cartilage formation. This is an important first step toward personalized cartilage repair strategies for OA patients.

Age-related alterations and senescence of mesenchymal stromal cells: Implications for regenerative treatments of bones and joints

The most common clinical manifestations of age-related musculoskeletal degeneration are osteoarthritis and osteoporosis, and these represent an enormous burden on modern society. Mesenchymal stromal cells (MSCs) have pivotal roles in musculoskeletal tissue development. In adult organisms, MSCs retain their ability to regenerate tissues following bone fractures, articular cartilage injuries, and other traumatic injuries of connective tissue. However, their remarkable regenerative ability appears to be impaired through aging, and in particular in age-related diseases of bones and joints. Here, we review age-related alterations of MSCs in musculoskeletal tissues, and address the underlying mechanisms of aging and senescence of MSCs. Furthermore, we focus on the properties of MSCs in osteoarthritis and osteoporosis, and how their changes contribute to onset and progression of these disorders. Finally, we consider current treatments that exploit the enormous potential of MSCs for tissue regeneration, as well as for innovative cell-free extracellular-vesicle-based and anti-aging treatment approaches.

Knee joint distraction results in MRI cartilage thickness increase up to ten years after treatment

Objectives

Knee joint distraction (KJD) has been shown to result in long-term clinical improvement and short-term cartilage restoration in young OA patients. The objective of the current study was to evaluate MRI cartilage thickness up to 10 years after KJD treatment, using a 3D surface-based approach.

Methods

Twenty end-stage knee OA patients were treated with KJD. MRI scans (1.5 T) were performed before and at 1, 2, 5, 7, and 10 years after treatment. Tibia and femur cartilage segmentation and registration to a canonical surface were performed semi-automatically. Statistical parametric mapping with linear mixed models was used to analyse whole-joint changes. The influence of baseline patient characteristics was analysed with statistical parametric mapping using linear regression. Relevant weight-bearing parts of the femur were selected to obtain the average cartilage thickness in the femur and tibia of the most- (MAC) and least-affected compartment. These compartmental changes over time were analysed using repeated measures ANOVA; missing data was imputed. In all cases, P <0.05 was considered statistically significant.

Results

One and 2 years post-treatment, cartilage in the MAC weight-bearing region was significantly thicker than pre-treatment, gradually thinning after 5 years, but still increased at 10 years post-treatment. Long-term results showed that areas in the least-affected compartment were significantly thicker than pre-treatment. Male sex and more severe OA at baseline somewhat predicted shorter-term benefit (P >0.05). Compartmental analyses showed significant short- and long-term thickness increase in the tibia and femur MAC (all P <0.05).

Conclusion

KJD results in significant short- and long-term cartilage regeneration, up to 10 years post-treatment.

Trial registration

Netherlands Trial Register, https://www.trialregister.nl, NL419.