Cite this article: Bone Joint Res 2023;12(5):309–310.

Cite this article: Bone Joint Res 2023;12(5):306–308.

Articular cartilage (AC) and subchondral bone (SB) are intimately intertwined, forming a complex unit called the AC-SB interface. Our recent studies have shown that cartilage and bone marrow are connected by a three-dimensional network of microchannels (i.e. cartilage-bone marrow microchannel connector; CMMC), which differ microarchitecturally in number, size and morphology depending on the maturation stage of the bone and the region of the joint. However, the pathological significance of CMMC is largely unknown. Here, we quantitatively assessed how CMMC microarchitecture relates to cartilage condition and regional differences in early idiopathic osteoarthritis (OA). Two groups of cadaveric female human femoral heads (intact cartilage vs early cartilage lesions) were identified and biopsy-based high-resolution micro-CT imaging was used. Subchondral bone (SB) thickness, CMMC number, maximum and minimum CMMC size, and CMMC morphology were quantified and compared between the two groups. The effect of joint region and cartilage condition on each dependent variable was examined. The number and morphology of CMMCs were influenced by the region of the joint, but not by the cartilage condition. On the other hand, the minimum and maximum CMMC size was modified by both joint location and cartilage condition. The smallest CMMCs were consistently found in the load bearing region (LBR) of the joint. Compared to healthy subjects, the size of the microchannels was increased in early OA, most notably in the non-load bearing region (NLBR) and the peripheral rim (PR) of the femoral head. In addition, subchondral bone thinning was observed in early OA as a localized event associated with areas of partial chondral defect. Our data suggest an enlargement of the SB microchannel network and a collective structural deterioration of the SB in early idiopathic OA

Cartilage degeneration and loss are key events in the initiation and progression of osteoarthritis (OA). Changes to chondrocyte volume and morphology (in the form of cytoplasmic processes) and thus cell phenotype are implicated, as they lead to the production of a mechanically-weakened extracellular matrix. The chondrocyte cytoskeleton is intimately linked to cell volume and morphology and hence we have investigated alterations to levels and distribution of chondrocyte F-actin that occur during early OA. The femoral heads (FH) from hip joints (N=16) were obtained with ethical permission and patient consent following femoral neck fracture. Cartilage was assessed as grade 0 (non-degenerate) and grade 1 (superficial fibrillation) using OARSI criteria. In situ chondrocyte volume and F-actin distribution were assessed using the fluorescent indicators (5-chloromethyl fluorescein diacetate (CMFDA)) and phalloidin, and imaged and quantified by confocal microscopy, Imaris. TM. and ImageJ software. There were no differences between the volume or total F-actin levels of in situ chondrocytes within the superficial zone of grade 0 (n=164 cells) compared to grade 1 (n=145) cartilage (P>0.05). However, a more detailed analysis of phalloidin labelling was performed, which demonstrated significant increases in both intense punctuate (IP) or intense areas (IA) (P<0.0001; P=0.0175 respectively). A preliminary analysis of IP and IA F-actin labelling suggested that while the former did not appear to be associated with changes to chondrocyte morphology, most of the cytoplasmic processes were associated with the presence of IA at the starting point of the protrusion. These results demonstrate marked changes to F-actin distribution in chondrocytes in the very early stages of cartilage degeneration as occurs in OA. These subtle changes are probably an early indication of a change to the chondrocyte phenotype and thus worthy of further study as they may lead to deleterious alterations to matrix metabolism and ultimately cartilage weakening

Osteoarthritis (OA) is a progressive and degenerative joint disease resulting in changes to articular cartilage. In focal early OA defects, autologous chondrocyte implantation (ACI) has a 2-fold failure rate due to poor graft integration and presence of inflammatory factors (e.g. Interleukin-1β). Bone marrow derived mesenchymal stem cells (MSCs) are an alternative cell source for cell-based treatments due to their chondrogenic capacity, though in vivo implantation leads to bone formation. In vivo, chondrocytes reside under an oxygen tension between 2–7% oxygen or physioxia. Physioxia enhances MSC chondrogenesis with reduced hypertrophic marker (collagen X and MMP13) expression compared to hyperoxic conditions (20% oxygen). This study sought to understand whether implantation of physioxic preconditioned MSCs improves cartilage regeneration in an early OA defect model compared to hyperoxic MSCs. Bone marrow extracted from New Zealand white rabbits (male: 5–6 months old; n = 6) was split equally for expansion under 2% (physioxia) or 20% (hyperoxia) oxygen. Chondrogenic pellets (2 × 105 cells/pellet) formed at passage 1 were cultured in the presence of TGF-β1 under their expansion conditions and measured for their wet weight and GAG content after 21 days. During bone marrow extraction, a dental drill (2.5mm diameter) was applied to medial femoral condyle on both the right and left knee and left untreated for 6 weeks. Following this period, physioxia and hyperoxia preconditioned MSCs were seeded into a hyaluronic acid (TETEC) hydrogel. Fibrous tissue was scraped and then MSC-hydrogel was injected into the right (hyperoxic MSCs) and left (physioxia MSCs) knee. Additional control rabbits with drilled defects had fibrous tissue scrapped and then left untreated without MSC-hydrogel treatment for the duration of the experiment. Rabbits were sacrificed at 6 (n = 3) and 12 (n = 3) weeks post-treatment, condyles harvested, decalcified in 10% EDTA and sectioned using a cryostat. Region of interest was identified; sections stained with Safranin-O/Fast green and evaluated for cartilage regeneration using the Sellers scoring system by three blinded observers. Physioxic culture of rabbit MSCs showed significantly shorter doubling time and greater cell numbers compared to hyperoxic culture (∗p < 0.05). Furthermore, physioxia enhanced MSC chondrogenesis via significant increases in pellet wet weight and GAG content (∗p < 0.05). Implantation of physioxic preconditioned MSCs showed significantly improved cartilage regeneration (Mean Sellers score = 7 ± 3; ∗p < 0.05) compared to hyperoxic MSCs (Sellers score = 12 ± 2) and empty defects (Sellers score = 17 ± 3). Physioxia enhances in vitro rabbit MSC chondrogenesis. Subsequent in vivo implantation of physioxia preconditioned MSCs improved cartilage regeneration in an early OA defect model compared to hyperoxic MSCs. Future studies will investigate the mechanisms for enhanced in vivo regeneration using physioxia preconditioned MSCs

Osteoarthritis (OA) is one of the most prevalent joint diseases involving progressive and degenerative changes to cartilage resulting from a variety of etiologies including post-traumatic incident or aging. OA lesions can be treated at its early stages through cell-based tissue engineering therapies using Mesenchymal Stem Cells (MSCs). In vivo models for evaluating these strategies, have described both chondral (impaction) and osteochondral (biopsy punch) defects. The aim of the investigation was to develop a compact and reproducible defect inducing post-traumatic degenerative changes mimicking early OA. Additionally, a pilot study to evaluate the efficacy of MSC-hydrogel treatment was also assessed. Surgery was performed on New Zealand white rabbits (male, 5–8 months old) with defects created on medial femoral condyle. For developing an appropriate defect, three approaches were used for evaluation: a biopsy punch (n = three at six and twelve weeks), an impaction device1 (n = three at six and twelve weeks) and a dental drill model (n = six at six and twelve weeks). At stated time points, condyles were harvested and decalcified in 10% EDTA, then embedded in Tissue-Tek and sectioned using a cryostat. Upon identification of region of interest, sections were stained with Safranin-O/Fast green and scored using OARSI scoring system by two blinded observers2. For the pilot study, autologous bone marrow was harvested from rabbits and used to isolate and expand MSCs. The Dental drill model was applied to both knee condyles, left untreated for six weeks at which stage, PKH26 fluorescently labelled MSCs were seeded into a hyaluronic acid hydrogel (TETEC). Repair tissue was removed from both condyles and MSC-hydrogel was injected into the left knee, whilst right knee was left empty. Rabbits were sacrificed at one (n = 1), six (n = 3) and twelve (n = 3) weeks post-treatment, processed as previously described and cartilage regeneration evaluated using Sellers score3. Impacted condyles exhibited no observed changes histologically (Mean OARSI score = 1 + 1), whereas biopsy punched and dental drilled defects demonstrated equal signs of cartilage erosion (OARSI score = 3 + 1) at assessed time points. However, biopsy punched condyles formed a diffusive defect, whereas dental drilled condyles showed a more defined, compact and reproducible defect. In the pilot study, PKH-labelled MSCs were observed at one and six weeks post-implantation within the defect space where hydrogel was injected. Tissue regeneration assessment indicated no difference between empty (Mean Sellers score = 14 + 2) and MSC treated defects (Sellers score = 16 + 5) at six weeks post-injection. At twelve weeks, MSC treated defects showed improved tissue regeneration with substantial subchondral bone restoration and good integration of regenerative cartilage with surrounding intact tissue (Sellers score = 10 + 1), whereas untreated defects showed no change in regeneration compared to six weeks (Sellers score = 16 + 2). Dental drill model was found to be the appropriate strategy for investigating early OA progression and treatment. Application of MSCs in defects showed good cartilage regeneration after twelve weeks application, indicating their promise in the treatment of early OA defects

Aims. This study aimed, through bioinformatics analysis, to identify the potential diagnostic markers of osteoarthritis, and analyze the role of immune infiltration in synovial tissue. Methods. The gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were identified by R software. Functional enrichment analyses were performed and protein-protein interaction networks (PPI) were constructed. Then the hub genes were screened. Biomarkers with high value for the diagnosis of early osteoarthritis (OA) were validated by GEO datasets. Finally, the CIBERSORT algorithm was used to evaluate the immune infiltration between early-stage OA and end-stage OA, and the correlation between the diagnostic marker and infiltrating immune cells was analyzed. Results. A total of 88 DEGs were identified. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that DEGs were significantly enriched in leucocyte migration and interleukin (IL)-17 signalling pathways. Disease ontology (DO) indicated that DEGs were mostly enriched in rheumatoid arthritis. Six hub genes including FosB proto-oncogene, AP-1 transcription factor subunit (FOSB); C-X-C motif chemokine ligand 2 (CXCL2); CXCL8; IL-6; Jun proto-oncogene, AP-1 transcription factor subunit (JUN); and Activating transcription factor 3 (ATF3) were identified and verified by GEO datasets. ATF3 (area under the curve = 0.975) turned out to be a potential biomarker for the diagnosis of early OA. Several infiltrating immune cells varied significantly between early-stage OA and end-stage OA, such as resting NK cells (p = 0.016), resting dendritic cells (p = 0.043), and plasma cells (p = 0.043). Additionally, ATF3 was significantly correlated with resting NK cells (p = 0.034), resting dendritic cells (p = 0.026), and regulatory T cells (Tregs, p = 0.018). Conclusion. ATF3 may be a potential diagnostic marker for early diagnosis and treatment of OA, and immune cell infiltration provides new perspectives for understanding the mechanism during OA progression. Cite this article: Bone Joint Res 2022;11(9):679–689

Osteoarthritis is a degenerative disease mainly caused by aging, although in younger patients (aged 25 – 50) it can be a consequence of sports-related injuries or trauma. This results in early osteoarthritis with subsequent changes in cartilage extracellular matrix. Cell-based tissue engineering approaches using mesenchymal stem cells (MSCs) are an ideal cell type for the treatment of early osteoarthritc defects. Our group has demonstrated in a clinical study, that interleukin-1β (IL-1β) was expressed in cartilage plugs from patients with early osteoarthritis. In vitro studies have shown that IL-1β inhibits cartilage formation in chondrocytes or MSCs undergoing chondrogenesis. However, these studies show complete inhibition of tissue formation, whereas in the context of early osteoarthritis, cartilage extracellular matrix remains around the defect site. Thus, the present study sought to develop a model mimicking early osteoarthritis using MSCs. Method. Human MSCs (Male donors; aged 18–60 years, n = 6) were isolated from bone marrow and expanded in culture for one passage. 2 × 10. 5. MSCs were aliquoted into wells of a 96-well cell culture plate in the presence of 10ng/ml TGF-β. 1. or in combination with IL-1β administered at a range of concentrations (0.1, 0.5, 1 and 10ng/ml) and centrifuged to form pellets. Pellets were removed from culture on days 7, 14 and 21. Pellets were evaluated for wet weight, pellet area, histological (DMMB staining, collagen type I, II, MMP-13 and TGF-β receptor II) and collagen type II ELISA analysis. Results. Chondrogenic pellets in the presence of IL-1β demonstrated a dose-dependant inhibition in chondrogenesis. Concentrations equal or greater than 0.5ng/ml IL-1β showed significant reduction (p < 0.05) in pellet area and wet weight, with no positive staining for collagen type I, II (including ELISA analysis) and DMMB. However, at 0.1ng/ml IL-1β, despite a slight reduction in pellet area, positive staining for collagen type I, II and DMMB was observed. Furthermore, MMP-13 matrix staining was increased and TGF-b receptor II staining was decreased in pellets at IL-1β concentrations above 0.5ng/ml. Discussion. A dose dependant catabolic response in cartilage extracellular matrix formation was demonstrated for IL-1β treated MSCs undergoing chondrogenesis. At concentrations equal or greater than 0.5ng/ml IL-1β, MMP13 expression was observed in the matrix, indicative of osteoarthritis. Furthermore, there was reduced expression of TGF-β receptor II under these conditions that is required for TGF-b induced chondrogenesis. However, at 0.1ng/ml IL-1β, a reduced catabolic response in extracellular matrix components was observed, whilst showing a moderate expression in MMP-13 and the presence of cellular TGF-β receptor II expression. Therefore, this latter model may be used to develop pro-chondrogenic strategies for the treatment of early osteoarthritic defects

Anterior cruciate ligament (acl) reconstruction is one of the most commonly performed procedures in orthopedics for acl injury. While literature suggest short-term good-to-excellent functional results, a significant number of long-term studies report unexplained early oa development, regardless type of reconstruction. The present study reports the feasibility analysis and development of a clinical protocol, integrating different methodologies, able to determine which acl reconstruction technique could have the best chance to prevent oa. It gives also clinicians an effective tool to minimize the incidence of early oa. A prospective clinical trial was defined to evaluate clinical outcome, biochemical changes in cartilage, biomechanical parameters and possible development of oa. The most common reconstruction techniques were selected for this study, including hamstring single-bundle, single-bundle with extraarticular tenodesis and anatomical double-bundle. Power analysis was performed in terms of changes at cartilage level measurable by mri with t2 mapping. A sample size of 42 patients with isolated traumatic acl injury were therefore identified, considering a possible 10% to follow-up. Subjects presenting skeletal immaturity, degenerative tear of acl, other potential risk factors of oa and previous knee surgery were excluded. Included patients were randomized and underwent one of the 3 specified reconstruction techniques. The patients were evaluated pre-operatively, intra-operatively and post-operatively at 4 and 18 months of follow-up. Clinical evaluation were performed at each time using subjective scores (koos) and generic health status (sf-12). The activity level were documented (marx) as well as objective function (ikdc). Preliminary results allow to verify kinematic patterns during active tasks, including level walking, stair descending and squatting using dynamic roentgen sterephotogrammetric analysis (rsa) methodology before and after the injured ligament reconstruction. Intra-operative kinematics was also available by using a dedicated navigation system, thus to verify knee laxity at the time of surgery. Additionally, non-invasive assessment was possible both before the reconstruction and during the whole follow-up period by using inertial sensors. Integrating 3d models with kinematic data, estimation of contact areas of stress patterns on cartilage was also possible. The presented integrate protocol allowed to acquired different types of information concerning clinical assessment, biochemical changes in cartilage and biomechanical parameters to identify which acl reconstruction could present the most chondroprotective behavior. Preliminary data showed all the potential of the proposed workflow. The study is on-going and final results will be shortly provided

Background. It is still controversial whether “labral tear” in the pelvis or “pincer type's femoroacetabular impingement syndrome” should be considered a pathologic lesion, and whether they cause the early onset of osteoarthritis in the pelvis. Hypothesis. The disruption of chondrolabral junction causes degenerative change on hip joint, and the disruption of the vessel tissue to the labrum induces the rapidly progressive degeneration of outside in osteoarthritis changes. Methods. Femoral acetabulum has been escaped from the chondrolabral junction and expanded to the acetabulum inside or outward. Therefore we report the cases. Results. We found cases which has chondrolabral junction disruptive slippage, and disruption of the vessel tissue and inverted or everted labral pathologic lesion, which we named COLADIS, chondrolabral junction disruptive slippage. Conclusion. COLADIS (chondrolabral junction disruptive slippage) caused symptoms on patient's hip, and may be the pre-pathologic lesion of early osteoarthritis

Defects of the joint cartilage are of enormous medical and socio-economic impact. Meanwhile is widely acknowledged that untreated cartilage defects lead to an early onset of osteoarthritis. Intrinsic factors for the genesis of osteoarthritis are unknown. It is wellknown however that joint cartilage has only a limited capacity of regeneration. The conservative treatment of early osteoarthritis should focus on the following principles: Limit the pain. Various drugs are available for the symptomatic treatment of osteoarthritis (e.g. NSAIR, cortison, herbal preparations). Intrarticular injections with antiinflammatory agents (e.g. hyaluronan, cortison, IL-1 antagonists) have been proven to reduce pain and dysfunction. Orthetic devices are able to unload joint compartments destroyed by osteoarthritic cartilage lesions. Arthroscopic lavage and debridement eliminate inflammation mediating substances and balance the synovial environment. Maintain the function. Physiotherapy and massage fight the stiffness of the joint and enhance the periarticular circulation. Daily activity should be encouraged and supported e.g. by walking aids and custom-made shoewear. Reduce factors for progression. A successful dietary program can minimize overload of osteoarthritic joints. Surgical procedures to restore and maintain meniscal function, joint stability and physiological loading are beneficial to prevent further cartilage deterioration. Regeneration of cartilaginous surfaces e.g. by marrow stimulation techniques or autologous chondrocyte transplantation will ease joint function and inhibit enzymatic degradation of healthy cartilage. In the last 10 years modern biochemical and cell biological techniques opened new horizons for the treatment of cartilage defects and osteoarthritis Future will teach us the value of cartilage regeneration to treat osteoarthritis. The biologic approach of cell based therapies and the arthroscopic application of resorbable implants widen the indications for the conservative surgical treatment of osteoarthritis

Introduction. The management of early OA in young patients with joint preservation techniques utilizing cartilage repair remains challenging and a suitable treatment remains unclear. The management of bipolar chondral lesions in the patello-femoral (PF) and in the tibio-femoral (TF) compartment with cartilage repair is especially troublesome. The purpose of this study was to evaluate the clinical outcomes and survivorship after ACI for the treatment of bipolar chondral lesions in the PF and TF compartment. Methods. This was an IRB approved, prospectively collected case series, level 4 study. We evaluated 115 patients. 58 patients who had ACI for the treatment of symptomatic bipolar chondral lesions in the PF compartment and 57 in the TF compartment with a minimum 2-year follow up. A single surgeon performed all the surgeries between October 1995 and June 2014. In the PF group, all 58 patients (60 knees; mean age, 36.6 years) were included, and for the TF group one patient did not return for follow-up, 56 patients (58 knees) were included. For the PF group, an average size of the patella and trochlea lesions were 5.6 ± 2.7 cm2 and 4.2 ± 2.8 cm2, respectively. For the TF group, an average of 3.1 lesions per knee were treated, representing a total surface area of 16.1 cm2 (range, 3.2 – 44.5 cm2) per knee. Patients were evaluated with the modified Cincinnati Knee Rating Scale, Visual Analogue Scale, Western Ontario and McMaster Universities Osteoarthritis Index, and the Short Form 36. Patients also answered questions regarding self-rated knee function and satisfaction with the procedure. Standard radiographs were evaluated for progression of OA. Results. Patients did well for bipolar ACI in both compartments. In the PF compartment overall, the survival rate was 83% and 79% at 5 and 10 years, respectively. Of the 49 (82%) knees with retained grafts, all functional scores significantly improved postoperatively with a very high satisfaction rate (88%) at a mean of 8.8 years after ACI (range, 2 – 16 years). Outcomes for 11 patients were considered as failures at a mean of 2.9 years. In the TF group, the overall survival rate was 80% at 5 years and 76% at 10 years. Significantly better survival rate in patients with the use of collagen membrane than periosteum (97% vs. 61% at 5 years, P = 0.0014) was found. Of 46 knees with retained grafts, all functional scores significantly improved postoperatively with a very high satisfaction rate (85%) at a mean of 8.3 years after ACI (range, 2–20 years). Outcomes for 12 patients were considered as failures at a mean of 4.1 years. Of them, 9 patients were converted to a partial or total knee arthroplasty at a mean of 4.4 years. Two patients had revision ACI at 5 and 17 months. The other one patient did not require a revision surgery. At the most recent follow-up for both groups there was no radiographic progression to OA. Conclusions. Our study showed that ACI for the treatment of bipolar chondral lesions in the PF and TF compartments provided successful clinical outcomes in patients with retained grafts and could possibly prevent or delay OA progression. The best results in the PF joint are as primary repairs and not after failed osteotomy or cartilage repair with a 91% 10-year survival. Collagen membrane is more encouraging than periosteum for bipolar lesions in both the PF and TF compartments. ACI could be an adequate salvage procedure for bipolar chondral lesions in the TF compartment for the relatively young arthritic patient who wishes to avoid an arthroplasty

INTRODUCTION. There is no effective therapy available today that alters the pathobiologic course of osteoarthritis. Recent advances have shown Mesenchymal stem cells to be a potential disease modifying treatment. Considering the tissue differentiation property and vast paracrine effects of MSCs we proposed the present study to find out the safety and efficacy of Mesenchymal stem cells in osteoarthritis of knee joint. METHODS. 12 patients with grade 1and2 bilateral osteoarthritis knee (Ahlbacks radiological grading) were selected. 8–10 ml of bone marrow was aspirated under strict aseptic precautions from the iliac spine. After the stem cell culture and expansion for 4–6 weeks the MSC suspension in 10xPBS was injected directly into the 24 knees by lateral approach. The outcome was evaluated by modified VAS score, WOMAC score, KOOS and MRI measurement of knee articular cartilage integrity by the modified WORMS score. RESULTS. Statistically significant improvement in VAS score, total WOMAC score and total KOOS score was observed from pre injection to 1st follow up at 6 weeks, 2nd follow up at 6 months and final follow up of mean 26.7 months. There was also a significant improvement from 1st follow up to 2nd and final follow up. The modified WORMS score showed a statistically significant decrease of 1.49 %. CONCLUSION. Intra-articular injection of autologous bone marrow derived culture-expanded MSCs can be considered a potential treatment of early osteoarthritis knee which relieves pain, stiffness, improves physical functions, and improves the articular cartilage integrity

INTRODUCTION

The major loss of articular cartilage in medial osteoarthritis occurs in a central band on the distal femur, and in the center of the tibial plateau (Figure). This is consistent with varus deformity due to cartilage loss and meniscal degeneration, together with the sliding regions in walking. Treatment at an early stage such as KL grade 2 or 3, has the advantages of little bone deformity and cruciate preservation, and could be accomplished by resurfacing only the arthritic areas with Early Intervention (EI) components. Such components would need to be geometrically compatible with the surrounding bearing surfaces, to preserve continuity and stability. However because of the relatively small surface area covered, compared with total knees and even unicompartmentals, it is hypothesized that EI components will be an accurate fit on a population of knees with only a small number of sizes, and that accuracy can be maintained without requiring right-left components. We examined this hypothesis using unique design and methodology.

Summary Statement

This work proved by prospective clinical and radiological controlled study that the best regimen for treatment of early KOA is combination of NSAIDS, physiotherapy, vasoprotective and vasodilator drugs, and alendronate.

The clinical results of carbon matrix support prostheses for treatment of articular cartilage defects of the femoral condyle and patella were assessed in 97 patients (100 prostheses) between 1989–99. Patients were independently reviewed by subjective and objective criteria. Pre-operative and current visual analogue scores for pain (VAPS); Stanmore and modified Cincinnati functional rating scores were obtained. Forty-nine patients had lesions of the patella, forty-four patients of the medial femoral condyle and seven patients of the lateral femoral condyle.

Patella group – subjectively 49% reported they were improved, 8% unchanged and 43% worse. Stanmore score: 6 excellent and 17 good (47%), 5 fair and 21 were poor. The Cincinnati score increased from 26. 5 pre-operatively to 47. 5 currently (p< 0. 001). The mean VAPS decreased from 8. 1 to 5. 0 (p< 0. 001).

Medial femoral condyle group – subjectively 60% reported they were improved, 14% unchanged and 26% worse. Stanmore score: 8 excellent and 16 good (55%), 8 fair and 12 poor. The Cincinnati score increased from 22. 3 pre-operatively to 48. 5 currently (p< 0. 001). The mean VAPS decreased from 8. 6 to 5. 1 (p< 0. 001).

Lateral femoral condyle group – subjectively 42% reported they were improved, 29% unchanged and 29% worse.

Stanmore score: 2 excellent and 1 good (43%), 2 fair and 2 poor. The Cincinnati score increased from 35. 0 pre-operatively to 52. 0 currently (p< 0. 25). The mean VAPS decreased from 6. 5 to 4. 0 (p< 0. 25).

There were no statistical differences in outcome based upon gender, site, pre-operative functional rating score, diagnosis, or any correlation with age or length of follow up, or when comparing excellent/good with fair/ poor subgroups in patellae or femoral condyles in relation to these variables.

This study demonstrated that 49% improved in the patella group, 60% in the medial femoral condyle and 43% in the lateral femoral condyle groups. The use of these prostheses was effective on the medial femoral condyle for periods up to 10 years but the use in the patella and lateral femoral condyle was less successful.

Femoroacetabular impingement recently was recognized as cause for osteoarthritis of the hip. There are two mechanism of impingement: (1) cam impingement caused by a non-spherical head, and (2) pincer impingement due to acetabular overcover. We hypothesized that both mechanism result in different articular damage patterns. Of 302 analyzed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused anterosuperior acetabular cartilage damage with a separation between labrum and cartilage. During flexion the cartilage is sheared off the bone by the non-spherical part of the femoral head. In pincer impingement the cartilage damage was located circumferentially, invovolving only a narrow strip along the acetabular rim. During motion the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification of the labrum.

Cam and pincer impingement are two basic mechanism that lead to osteoarthrosis of the hip. The articular damage pattern differs substantially. Isolated cam or pincer impingement is rare, in most hips a combination is present. Labral damage indicates ongoing impingement and rarely occurs alone.

It is unclear whether patients with early radiographic osteoarthritis (OA) but severe hip symptoms benefit from total hip replacement (THR). We aimed to assess which factors were associated with successful THR in this patient group. From a consecutive series of 1,935 patients undergoing THR we identified 70 (3.6%) patients with early OA (Kellgren and Lawrence (KL) grades 0-2). These were compared with 200 patients with advanced OA (KL grades 3–4). Outcomes were Oxford Hip Scores (OHS), EQ5D and EQ-VAS scores; compared pre-operatively with one year post-operatively. We investigated which clinical and radiographic (plain x-ray, CT, MRI) features predicted successful THR in the early OA group. Success was defined as reaching a postoperative OHS≥42. The early OA group were significantly younger (61 vs 66 years; P=0.0035). There were no significant differences in body mass index, ASA grade or gender. After adjusting for confounders, the advanced OA group had a significantly greater percentage of possible change (PoPC) in OHS (75.8% versus 50.4%; P<0.0001) and improvement in EQ5D (0.151 versus 0.002; P<0.0001). There were no significant differences in complication, revision or readmission rates. In the early OA group, we identified 16/70 (22.9%) patients who had a ‘successful’ THR. Of those with early OA, 38 patients had pre-operative CT or MRI scans. Patients who had a ‘successful’ THR were significantly more likely to have subchondral cysts on CT/MRI (91.7% versus 57.7%; P=0.0362). The presence of cysts on CT/MRI was associated with a significantly greater PoPC in OHS (61.6% versus 38.2%; P=0.0353). The combination of cysts and joint space width (JSW) <1mm was associated with a PoPC of 68%. Plain radiographs were found to significantly underestimate the narrowest JSW compared to CT/MRI (2.4mm versus 1.0mm; P<0.0001). We advise caution in performing THRs in patients with early OA (KL grades 0-2) on plain radiographs. We advocate pre-operative cross-sectional imaging (CT or MRI) in these patients. In the absence of cysts on cross-sectional imaging, a THR seems unlikely to provide a satisfactory outcome

Partial meniscectomy patients have a greater likelihood for the development of early osteoarthritis (OA). To prevent the onset of early OA, patient-specific treatment algorithms need to be created that predict patient risk to early OA after meniscectomy. The aim of this work was to identify patient-specific risk factors in partial meniscectomy patients that could potentially lead to early OA. Partial meniscectomy patients operated between 01/2017 and 12/2019 were evaluated in the study (n=317). Exclusion criteria were other pathologies or surgeries for the evaluated knee and meniscus (n = 114). Following informed consent, an online questionnaire containing demographics and the “Knee Injury and Osteoarthritis Outcome Score” (KOOS) questionnaire was sent to the patient. Based on the KOOS pain score, patients were classified into “low” (> 75) and “high” (< 75) risk patients, indicating risk to symptomatic OA. The “high risk” patients also underwent a follow-up including an MRI scan to understand whether they have developed early OA. From 203 participants, 96 patients responded to the questionnaire (116 did not respond) with 61 patients considered “low-risk” and 35 “high-risk” patients. Groups that showed a significant increased risk for OA were patients aged > 40 years, females, overweight (BMI >25 kg/m2 ≤ 30 kg/m2), and smokers (*p < 0.05). The “high-risk”-follow-up revealed a progression of early osteoarthritic cartilage changes in seven patients, with the remaining nineteen patients showing no changes in cartilage status or pain since time of operation. Additionally, eighteen patients in the high-risk group showed a varus or valgus axis deviation. Patient-specific factors for worse postoperative outcomes after partial meniscectomy and indicators for an “early OA” development were identified, providing the basis for a patient-specific treatment approach. Further analysis in a multicentre study and computational analysis of MRI scans is ongoing to develop a patient-specific treatment algorithm for meniscectomy patients

Osteoarthritis (OA) is the most common degenerative joint disorder. Its multifactorial etiology includes age, sex, joint overloading, genetic or nervous influences. In particular, the autonomic nervous system is increasingly gaining in importance. Its two branches, the sympathetic (SNS) and parasympathetic nervous system, are well-balanced under healthy conditions. OA patients seem to be prone to an autonomic imbalance and therefore, we analyzed their autonomic status. More than 200 participants including patients with early and late stage knee OA (before and 1 year after knee replacement surgery) and healthy probands (age-matched) were analyzed. Heart rate variability was measured via electrocardiogram to assess long-term sympathetic (low-frequency=LF) and parasympathetic (high-frequency=HF, pRR50) activities or general variability (RMSSD, SDRR). Serum cortisol concentrations were measured by ELISA. Perceived chronic stress (PSQ) was assessed via questionnaire. Multivariant regression was performed for data analysis. LF/HF value of early OA was slightly increased compared to healthy controls but significantly higher compared to late OA patients before (p>0.05) and after TKR (p>0.01). HF in late OA patients before TKR was significantly decreased compared to patients after TKR (p>0.001) or healthy controls (p>0.05). Healthy probands exhibited the highest SDRR values, early OA patients had slightly lower levels and late OA patients before TKR displayed significantly reduced SDRR (p>0.001). The same differences were observed in pRR50 and RMSSD. Serum cortisol concentrations and PSQ scores increased in late OA patients before TKR. At the time point of TKR, women with beta blocker medication had significantly higher age (71 ± 9 years) than those without (63 ± 12 years)(p>0.01). An autonomic dysfunction with sympathetic dominance occurs in OA patients. The fact that beta blocker medication in women delayed the need of TKR indicates that SNS inhibition might counteract OA. Future therapeutic interventions for OA should consider a systemic approach with special regard on the ANS