INTRODUCTION. Tamura et al. proposed a new friction test to measure the maturity of surface gel-hydration-like lubrication using MPC-polymer (2-Methacryloyloxyethyl phos -phorylcholine polymer) grafted surface as aãζζcounter surface. They suggested that the MPC-polymer grafted surface makes it possible to mimic in-vivo-like condition. Therefore, we can evaluate a lubricating ability of cartilage surface except for the possible effects of deformation resistance. By the way, reduction of lubricating ability of articular cartilage surface has much to do with pathogenesis of primary osteoarthritis. On the other hand, intraarticular injections of hyaluronic acid (HA) has been reported to have some clinical effect, however, it has not been clearly supported that HA restores a lubricating ability of injured cartilage surface. In the present study, the short-term effect of HA on injured cartilage surface's frictional performance was examined by the friction test using MPC-polymer grafted surface. METHODS. Articular cartilage specimens were taken from porcine femoral condyle and cut into 5 mm diameter plugs. Their surfaces were wiped with particular papers soaked in saline solution. Thereafter, these specimens were preserved with 1 mL volume of HA and saline solution for 0, 3, 6, 9 hours. The concentration of HA was 1% (w/v) in saline solution (MW=9×10. 5. Daltons; Seikagaku corp., Tokyo, Japan). Friction test was carried out in saline solution under a constant pressure of 1.5 Mpa and a relative sliding velocity of 0.8 mm/s, with MPC-polymer grafted glass as counter surface. Besides, superficial layer of cartilage tissue was histologically observed by two kinds of staining method: Toluidine blue (pH7.0) staining and Toluidine blue (pH2.5) staining Then, the Toluidine blue (pH7.0) staining intensity on superficial tissue was quantitatively analyzed. As follows, images of the stained cartilage specimens were analyzed by ImageJ. Measure RGB program was used to average out luminance values of blue in 2.7 μm square area of superficial layer and middle layer. The ration of the mean value in superficial layer and it in middle layer was defined as Toluidine blue (pH7.0) Index. RESULTS & DISCUSSION. Results of the friction test showed that the friction coefficients were inclined to decline with preservation time in both of the preservative solutions, and that the inclination was more remarkable in the HA-preserved case (Fig. 1). It suggests that the preservation with HA solution accelerate the recovery of friction coefficient in the short term. Superficial layer of cartilage tissues was positively stained with both Toluidine blue (pH7.0) and (pH2.5) staining, and only the (pH7.0) staining was changed with preservation time. As hyaluronan, mucoitin sulfate and chondroitin sulfate were stained by the toluidine blue (pH7.0), and hyaluronan was not stained by the toluidine blue (pH2.5), the toluidine blue (pH7.0) Index is thought to be rough indication for amount of surface hyaluronan concentration. As sown in Fig. 2, the toluidine blue (pH7.0) Index was inclined to increase with preservation time in both of the preservative solutions. This suggested that the decline of friction coefficient in HA-preserved specimen was not caused by histological repair but by adsorption of exogenous hyluronan

Osteochondral (OC) defects of the knee are associated with pain and significant limitation of activity. Studies have demonstrated the therapeutic efficacy of mesenchymal stem cell (MSC) therapies in treating osteochondral defects. There is increasing evidence that the efficacy of MSC therapies may be a result of the paracrine secretion, particularly exosomes. Here, we examine the effects of MSC exosomes in combination with Hyaluronic Acid (HA) as an injectable therapy on functional osteochondral regeneration in a rabbit osteochondral defect model. Exosomes were purified from human MSC conditioned medium by size fractionation. A circular osteochondral defect of 4.5 mm diameter and 2.5 mm depth was surgically created in the trochlear grooves of 16 rabbit knees. Thereafter, eight knees received three weekly injections of 200 µg of exosomes in one ml of 3% HA, and the remaining eight knees received three weekly injections of one ml of 3% HA only. The rabbits were sacrificed at six weeks. Analyses were performed by macroscopic and histological assessments, and functional competence was analysed via Young Modulus calculation at five different points (central, superior, inferior, medial and lateral) of the repaired osteochondral defect site. MSC exosomes displayed a modal size of 100 nm and expressed exosome markers (CD81, TSG101 and ALIX). When compared to HA alone, MSC exosomes in combination with HA showed significantly better repair histologically and biomechanically. The Young Modulus was higher in 4 out of the 5 points. In the central region, the Young Modulus of MSC exosome and HA combination therapy was significantly higher: 5.42 MPa [SD=1.19, 95% CI: 3.93–6.90] when compared to HA alone: 2.87 MPa [SD=2.10, 95% CI: 0.26–5.49], p < 0 .05. The overall mean peripheral region was also significantly higher in the MSC exosome and HA combination therapy group: 5.87 MPa [SD=1.19, 95% CI: 4.40–7.35] when compared to HA alone: 2.70 MPa [SD=1.62, 95% CI: 0.79–4.71], p < 0 .05. The inferior region showed a significantly higher Young Modulus in the combination therapy: 7.34 MPa [SD=2.14, 95% CI: 4.68–10] compared to HA alone: 2.92 MPa [SD=0.98, 95% CI: 0.21–5.63], p < 0.05. The superior region showed a significantly higher Young Modulus in the combination therapy: 7.31 MPa [SD=3.29, 95% CI: 3.22–11.39] compared to HA alone: 3.59 MPa [SD=2.55, 95% CI: 0.42–6.76], p < 0.05. The lateral region showed a significantly higher Young Modulus in the combination therapy: 8.05 MPa [SD=2.06, 95% CI: 5.49–10.61] compared to HA alone: 3.56 MPa [SD=2.01, 95% CI: 1.06–6.06], p < 0.05. The medial region showed a higher Young Modulus in the combination therapy: 6.68 MPa [SD=1.48, 95% CI: 4.85–8.51] compared to HA alone: 3.45 MPa [SD=3.01, 95% CI: −0.29–7.19], but was not statistically significant. No adverse tissue reaction was observed in all the immunocompetent animals treated with MSC exosomes. Three weekly injections of MSC exosomes in combination with HA therapy results in a more functional osteochondral regeneration as compared to HA alone

Subchondral drillings for articular cartilage defects usually result in fibrocartilage repair, which is inferior biomechanically compared to hyaline cartilage. We postulate that intra-articular injections with autologous marrow-derived stem cells (MSC) and hyaluronic acid (HA) can improve the quality of repair cartilage. We tested this hypothesis in a goat model by creating an articular cartilage defect in the stifle joint and conducted subchondral drillings. The animals were divided into three groups: Group A (control) no injections, Group B (HA) weekly injection of 1 ml sodium hyaluronate for three weeks, Group C (HA+MSC) similar to Group B but with 2 mls autologous MSC in addition to HA. MSC were obtained by bone marrow aspiration, centrifuged, and divided into aliquots, which were cryopreserved. Fifteen animals were equally divided between the groups and sacrificed at 24 weeks after surgery where the joint was harvested and examined macroscopically and histologically. Of the 15 animals, two had died in Group A and one was excluded from Group C due to an infection. In Group A, repair constituted mainly of scar tissue, while in Group B, there was less scar tissue, with small amounts of proteoglycan and collagen II at the osteochondral junction. In contrast, repair cartilage from Group C animals demonstrated almost complete coverage of the defect with evidence of hyaline cartilage regeneration. Histology as assessed by Gill scoring was significantly better in Group C with one-way ANOVA giving an F-statistic of 10.611 with a p-value of 0.004, which was highly significant. Post-operative intra-articular injections of autologous MSC in combination with HA following subchondral drillings into chondral defects resulted in better cartilage repair

Subchondral drillings for articular cartilage repair give functional improvement that peaks at 24 months after surgery. We postulate that intra-articular injections with autologous peripheral blood stem cells (PBSC) and hyaluronic acid (HA) following subchondral drillings can improve the repair process. Thirty-four patients with full thickness chondral defects of the knee joint underwent subchondral drillings. The operated knees were then placed on continuous passive motion for a period of two hours per day for four weeks, with partial weight-bearing for the first six weeks. PBSC were harvested by apheresis and divided into aliquots which were cryopreserved. One week after surgery, weekly intra-articular injections of 2.5 mLs PBSC mixed with 2 mLs of sodium hyaluronate were given for five weeks after surgery. Patients were followed up for an average of 11 months (range 6–20) and assessed using serial MRI scans. Second look arthroscopy and chondral biopsies were obtained in five patients. International Knee Documentation Committee (IKDC) scores were compared with previous microfractures results from the Mithoefer cohort study using linear interpolation to generate time-based predicted values. The difference was compared using a two-tailed, one-sample T-test against a value of zero. Serial MRI scans showed healing of subchondral bone and evidence of cartilage regeneration that was confirmed on arthroscopy with good integration into surrounding cartilage with no delamination. Biopsy specimens showed attributes typical of hyaline cartilage with good cellular morphology, abundant proteoglycans and Type II collagen. No oedema or degenerative changes were seen. The IKDC data was on average 12.8 points (95% CI 6.5-19.1) higher than the Mithoefer group with p=0.0002. Intra-articular injections of PBSC and HA following subchondral drillings resulted in good repair tissue based on MRI, arthroscopic, and histological criteria, with IKDC scores superior to standard microfracture surgery

There are a number of different non-operative management options for patients with a painful knee secondary to osteoarthritis (OA). In 2013 the American Academy of Orthopaedic Surgeons developed an evidence-based clinical practice guideline addressing treatment of osteoarthritis of the knee. Strength of recommendations were designated as strong, moderate and inconclusive. Strong recommendations included: self-management program, NSAIDs or tramadol and no acupuncture, no glucosamine and chondroitin sulfate and no hyaluronic acid. The “No” recommendations for hyaluronic acid and glucosamine and chondroitin sulfate were quite controversial because orthopaedic surgeons argued that some of their patients benefited from these treatments. Moderate strength recommendations included weight loss, lateral wedge insoles and needle lavage. The evidence-based data was inconclusive with respect to valgus force unloading brace, manual physical therapy, acetaminophen, opioids and pain patches. The effectiveness of corticosteroid and platelet rich plasma (PRP) injections were also inconclusive. Unloader braces are available to decrease pressure on the involved compartment. There is data showing that these braces can be effective for some patients. However, there are concerns with patient compliance because of poor fit and discomfort. These braces seemed to be tolerated best when used for sports activities in patients with medial compartment arthritis. Oral anti-inflammatory agents are effective in relieving pain and are a good first line agent for patients with OA. There is significant interest in the use of PRP injections for management of patients with knee OA particularly when patients have already received a steroid and/or a hyaluronic acid injection. To date there are no appropriately powered multi-centered randomised trials demonstrating that PRP is effective in decreasing pain and function in knee OA. However, there are some studies that suggest PRP can be helpful for patients with OA. Further studies to determine the indications for PRP injections are necessary. PRP injections are not covered by insurance in the United States. In summary, the management of patients with painful OA of the knee needs to be individualised based on patient symptoms and expectations. Non-operative management can be effective in limiting pain and enhancing function

Traditionally, arthritis is a disease which generally affects the elderly population. However, the incidence in young patients is well described and is increasing with the ever-growing obese population. Currently, the non-surgical treatment of osteoarthritis consists of corticosteroid injections, hyaluronic acid injections, weight loss, physical therapy, bracing, orthotics, narcotics, and non-steroidal anti-inflammatory drugs (NSAIDS). Oral medications (NSAIDS, tramadol, and opioids) can provide effective pain relief. Improvement with NSAIDs has been reported to be 20% relative to baseline, with better improvements seen with selective cox-2 inhibitors, which also have reduced gastrointestinal and renal toxicity. Additionally, the recent AAOS guidelines strongly recommend using NSAIDs or tramadol for pain relief. Although narcotics are effective analgesics, their use in young arthritic patients can potentially predispose individuals to future opioid dependency, and thus should be used sparingly. The primary purpose of physical therapy is to improve range of motion, strengthen muscles, and improve proprioception. Currently, the AAOS strongly recommends that patients undergo self-management programs, strengthening, low-impact aerobic exercises, and neuromuscular education. Similarly, they moderately recommended that patients with a BMI ≥ 25 undergo weight loss for symptomatic arthritis. Bracing options consist of the following: off-loader braces and transcutaneous nerve stimulation braces. These work to either off-load pressure in the knee or to scramble small nerve pain sensation, respectively. Corticosteroid injections are used to minimise pain and reduce inflammation in the joint associated with arthritis. However, their long-term repetitive use in young patients is not recommended, and current AAOS guidelines are inconclusive on their effectiveness. Additionally, the AAOS guidelines strongly recommend against the use of acupuncture, glucosamine/chondroitin, and hyaluronic acid injections

In joint prostheses where ultra-high molecular weight polyethylene (UHMWPE) is used as bearing material, efficacious treatments such as crosslinking, addition of vitamin E and the grafting of phospholipid polymer are known to improve wear resistance. Under severe conditions of various daily activities, however, friction and wear problems in such prostheses have not yet been completely solved. In contrast, extremely low friction and minimum wear have been maintained for a lifetime in healthy natural synovial joints containing articular cartilage with superior lubricity. Accordingly, joint prostheses containing artificial hydrogel cartilage with properties similar to those of articular cartilage are expected to show superior tribological functions. In establishing the function of artificial hydrogel cartilage as a novel material for joint prostheses, the tribological properties of hydrogel materials used and synergistic performance with synovia constituents are both important. In this study, the influence of synovia constituents on friction and wear in artificial hydrogels was examined in reciprocating test and compared with that for articular cartilage. As biocompatible artificial hydrogel cartilage materials, three poly(vinyl alcohol) (PVA) hydrogels were prepared using the repeated freeze-thawing (FT) method, the cast-drying (CD) method and hybrid method for CD on FT, which are physically crosslinked with hydrogen bonding but differ in terms of structure and mechanical properties. First the frictional behavior of the PVA hydrogels and articular cartilage as ellipsoidal specimens was examined in reciprocating tests against a glass plate with a sliding speed of 20 mm/s under constant continuous loading. As shown in Fig.1, the three hydrogels exhibited different frictional behaviors in a saline solution. It is noteworthy that the hybrid gel maintained very low friction until the end of test. The CD gel showed slightly higher friction and a gradual increase. Meanwhile, the FT gel showed initial medium friction and a gradual increase echoing the time-dependent behavior of natural articular cartilage. Based on these observations, focus was placed on FT gel and articular cartilage to examine how synovia constituents influence friction and wear in these hydrogel materials. In human body, lubricating constituents in synovial fluids such as hyaluronic acid, proteins, glycoproteins and phospholipids are considered to reduce the coefficient of friction in solid-to-solid interaction. Here, the effects of hyaluronic acid (HA, molecular weight: 9.2×10. 5. ), serum proteins and phospholipid were examined. Dipalmitoylphosphatidylcholine (DPPC) was used as a typical phospholipid. As indicated in Fig.2 for repeated reciprocating tests, addition of HA alone was effective particularly for PVA-FT hydrogel. The combination of HA and DPPC was more effective in reduction of friction. The simulated synovial fluid (composed of HA 0.5 wt%, DPPC 0.01 wt%, albumin(Alb) 1.4 wt% and gamma-globulin (g-glob) 0.7 wt%) exhibited both low friction and minimum wear. The rubbing surfaces of articular cartilage and FT gel after tests are shown in Fig.3. On the articular cartilage surface, gel-like surface layer existed. On the FT gel surface, the original texture was observed without damage. These results indicate the importance of synovia constituents for the clinical application of artificial hydrogel cartilage in joint prostheses

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

Arthrosis of the hip joint can be a significant source of pain and dysfunction. While hip replacement surgery has emerged as the gold standard for the treatment of end stage coxarthrosis, there are several non-arthroplasty management options that can help patients with mild and moderate hip arthritis. Therefore, the purpose of this paper is to review early prophylactic interventions that may help defer or avoid hip arthroplasty. Nonoperative management for the symptomatic hip involves minimizing joint inflammation and maximizing joint mobility through intra-articular joint injections and exercise therapy. While weight loss, activity modifications, and low impact exercises is generally recommended for patients with arthritis, the effects of these modalities on joint strength and mobility are highly variable. Intra-articular steroid injections tended to offer reliable short-term pain relief (3–4 weeks) but provided unreliable long-term efficacy. Additionally, injections of hyaluronic acid do not appear to provide improved pain relief compared to other modalities. Finally, platelet rich plasma injections do not perform better than HA injections for patients with moderate hip joint arthrosis. Primary hip joint arthrosis is rare, and therefore treatment such as peri-acetabular osteotomies, surgical dislocations, and hip arthroscopy and related procedures are aimed to minimise symptoms but potentially aim to alter the natural history of hip diseases. The state of the articular cartilage at the time of surgery is critical to the success or failure of any joint preservation procedures. Lech et al. reported in a series of dysplastic patients undergoing periacetabular osteotomies that one third of hips survived 30 years without progression of arthritis or conversion to THA. Similarly, surgical dislocation of the hip, while effective for treatment of femoroacetabular impingement, carries a high re-operation rate at 7 years follow up. Finally, as the prevalence of hip arthroscopic procedures continues to rise, it is important to recognise that failure to address the underlying structural pathologies can lead to failure and rapid joint destruction. In summary, several treatment modalities are available for the management of hip pain and dysfunction in patients with a preserved joint space. While joint preservation procedures can help improve pain and function, they rarely alter the natural history of hip disease. The status of the articular cartilage at the time of surgery is the most important predictor of treatment success or failure

Background. Kohnodai Hospital merged with the National Center of Neurology and Psychiatry in Japan in 1987. Accordingly, we treat more patients with mental disorders than other hospitals. I treated two patients with schizophrenia for TKA. Case 1. A 44 year-old female with schizophrenia and malignant rheumatoid arthritis presented with bilateral knee pain and difficulty walking. Her range of motion (ROM) was: right knee; extension −95°, flexion 120°, left knee; extension −95°, flexion 120°. Her Knee Society Bilateral Score was 19 points, X-ray grade: Larsen 5, Steinbrocker grade: Stage 3, class 4. Pre-TKA, corrective casts improved her ROM (extension; right −75°, left −70°). She received right TKA in September, 2013, and left TKA in December 2015. Post-operation bilateral ROM: extension −15° and flexion 120°. After operation, she wore corrective casts. Post TKA, she received manipulation for bilateral knee contractions in 2015, and she began in-patient rehabilitation. Her progress was normal, and became able to stand easily with a walker. However, after discharge, she discontinued treatment for schizophrenia and refused outpatient rehabilitation, possibly due to her schizophrenia. Thereafter, she lost her ability to stand up easily. Her ROM worsened, right: extension −95°, flexion 115°, left: extension −75°, flexion 115°Knee Society Score; Bilateral 13 points. Case 2. A 69 year-old male with schizophrenia presented with right knee pain and received hyaluronic acid injections in his knee. He had diabetes and reflux esophagitis at first visit. His ROM was: extension −10° flexion120°, and his Knee Society Score was 34 points. He received TKA in November 2015. He began to walk with full weight bearing the following day after, while continuing his treatment for schizophrenia. In 2018, his ROM was: extension −15° and flexion 105°, Her Knee Society Score was 71 points, and he could ascend stairs normally. After discharge, he had continued rehabilitation together with satisfactory control of his schizophrenia, and his normal prognosis was achieved. Discussion. Schizophrenia affects about only about 1% of the population, and TKA with schizophrenia is rare. Refusing rehabilitation due to schizophrenia may adversely influence prognosis. Proper control of schizophrenia may be important to avoid patients' refusing rehabilitation. Conclusion. Refusing rehabilitation due to schizophrenia may adversely influence prognosis in schizophrenia patients receiving TKA, and working in tandem with a psychiatrist should be considered for such patients

Optimal treatment for symptomatic talus Osteochondral Lesions (OCLs) where primary surgical techniques have failed has not been established. Recent advances have focussed on biological repair such as Autologous Chondrocyte Implantation (ACI) however funding for this treatment is limited. Stem cell therapy in the ankle has not been assessed. The purpose of this pilot study was to evaluate the safety and efficacy of stem cell therapy in the treatment of ankle OCLs. The study was approved by the new procedures committee. Between January 2015 and December 2016, 26 patients, mean age of 36 years (range 16–58 years) with persisting disabling symptoms underwent Complete Cartilage Regeneration (CCR) using stem cells for failed primary treatment for ankle OCLs. Treatment involved iliac crest bone marrow aspiration, centrifugation to obtain bone marrow concentrate (BMC), and then injection of the BMC combined with hyaluronic acid into the OCL. Any necessary additional procedures, e.g. bone grafting or lateral ligament reconstruction were also undertaken. In 18 patients the lesion was on the medial talar dome, in 5 the lateral talar dome, 2 multiple, 1 tibial plafond. The Manchester-Oxford Foot Questionnaire (MOXFQ) was utilised to assess outcome. Average pre-operative MOXFQ scores were Walking dimension −78, Pain dimension − 65, and Social dimension − 64.2. Average 3 month post-operative MOXFQ scores were Walking − 54.8, Pain − 35.4, Social − 38.9. Average 6 month post-operative MOXFQ scores were Walking − 34.4, Pain − 35.4, Social − 28. Two patients from the beginning of the series had AOFAS scores only which improved from an average of 55 pre-operatively to 76 post-operatively. No early complications were noted. We conclude that CCR treatment is a safe treatment for talus OCLs in patients who have failed primary treatment. The procedure avoids two-stage surgery of ACI in some patients without large cysts. The early clinical outcome is favourable with no complications noted. Longer term follow-up is required

Chondral defects of the knee are common and often seen in young and active individuals. A novel single stage arthroscopic technique for the treatment of articular cartilage defects in the knee is described. This involves microfracture and application of concentrated bone marrow aspirate cells (BMAC) with fibrin and Hyaluronic Acid as a gel. After a representative preclinical study, the 5 year results of a prospective clinical study are presented. The pre-clinical study involved two groups of rabbits with standardised lesions treated with microfracture alone and microfracture combined with fibrin/HA/BMAC application. New cartilage from both groups was subjected to staining with H&E for tissue morphology, toluidine blue (collagen) and safranin O (GAG), immunohistochemistry with antibodies for collagen type I and II, and scanning and transmission electron microscopy to analyse the microstructural morphologies. The fibrin/HA/BMAC group scored better than the microfracture group on all tests. A subsequent prospective clinical study patients (n=60) with symptomatic ICRS grade III/IV chondral defects (lesion size 2–8cm2). The surgical procedure involved debridement of the lesion, micro-fracture and application of fibrin/HA/BMAC gel under CO2 insufflation. Patients underwent morphological evaluation with MRI (T2*-mapping and d-GEMRIC scans). Clinical assessment employed the Lysholm, IKDC and KOOS scores while radiological assessment was performed with MOCART score. At 5 years, Lysholm score was 78, compared to 51 pre-operatively (p<0.05). KOOS (symptomatic) improved to 90 from 66 (p<0.05). IKDC (subjective) went to 80 from 39 (p<0.05). The mean T2* relaxation-times for the repair tissue and native cartilage were 26 and 29.9 respectively. Average MOCART score for all lesions was 70. This technique shows encouraging clinical results at 5 year follow-up. The morphological MRI shows good cartilage defect filling and the biochemical MRI suggests hyaline like repair tissue

Introduction. Intra-articular (IA) injections of corticosteroids and hyaluronic acid (HA) products are used to treat patients with knee osteoarthritis pain that has not responded to more conservative treatment. Corticosteroids are a standard of care despite only suggestive clinical evidence of 12 or more weeks of pain relief. However the duration of pain relief with this treatment appears to be short and not a long term solution. Methods. A double-blinded, randomised, active controlled, multicentre non-inferiority trial with 442 subjects provided a pragmatic comparison of HA to methylprednisolone. These patients were collected prospectively and with excellent long term follow-up. Results. The HA responder rates were good at 12 weeks and better at the later time points (6 to 9 months) while the methylprednisolone rate decreased significantly by 26 weeks. Conclusion. HA appears to be a reasonable mid to long term solution for patients with Kellgren grade 1 and 2 arthritis. It lasts longer than steroids and has what appears to be a cost-effective advantage

(Case) 79-year-old woman. Past history, in 1989, right femur valgus osteotomy. in 1991, THA at left side. Follow-up thereafter. Hyaluronic acid injection for both knee osteoarthritis. (Clinical course)Her right hip pain getting worse and crawling indoors from the beginning of July 2013. We did right hybrid THA at August 2013(posterior approach, TridentHA cup, Exeter stem, Biolox Forte femoral head 28mm). But immediately, she dislocated twice than the third day after surgery because she became a delirium. It has been left by nurse for about 6 hours because of the midnight after the second dislocation. Next morning, check the dislocation limb position, closed reduction wasdone under intravenous anesthesia. As a result of waking up from the anesthesia, and complained of paralysis and violent pain in the right leg backward. A right lower extremity nerve findings, there is pain in the lower leg after surface about the calf, there was no apparent perception analgesia. Toe movement is weak, but the G-toe planter anddorsiflexion possible about M2, and neurological symptoms to relieved by flexion(above 70 degrees) of the right hip joint. Therefore, we thought that she suffered anterior dislocation of the sciatic nerve by the stem neck (retraction), judged to closed reduction was impossible, open reduction surgery was performed after waitingat hip flex position. But paralysis is gradually worsened during waiting surgery, toes movement had become impossible to operating room admission. Sciatic nerve is caught in front of the stem neck as expected, operative findings were able to finally reduction after removing the femoral head after dislocation. Anteversion of the cup was changed to 25 degrees from 15 degrees, and changed to 32mm diameter metal head and polyethylene liner. And we needed Intensive Care Unit(ICU) management after surgery for prevent recurrence of dislocation. Fitted with a hip brace for her, has not been re-dislocation. The sciatic nerve palsy improved in three months after the operation, the patient became able to walk without a cane. (Summary) We experienced a rare case suffered anterior dislocation of the sciatic nerve by the stem neck, and she had a good result after open reduction surgery

Cartilage repair strategies have been applied successfully to the knee, but only recently and with limited experience to the hip. The indications for these strategies have been well defined for the knee and are defined by the diameter and depth of the defects that are mainly post traumatic and degenerative. Viscosupplementation is an intra-articular therapy that theoretically restores the protective effects of hyaluronic acid. This therapy has been widely used for osteoarthritis of the knee with some early preliminary promising results for osteoarthritis of the hip. Microfracture can be performed arthroscopically or as part of an open procedure. This procedure is indicated for smaller lesions less than 3cm in diameter and 1cm in depth. Widely used in the knee, the results in the hip are limited but promising. The repair tissue is however fibrocartilage. Autologous chondrocyte transplantation can yield hyaline like repair cartilage with good mid- to long-term results in the knee. The indications are chondral defects greater than 3cm in diameter or osteochondral defects less than 1cm in depth. Its use in the hip has been limited with only a few published papers. The procedure requires two stages. The first stage which involves harvesting the cartilage can be done arthroscopically, and the second stage which involves transplantation of the cultured chondrocytes can be done arthroscopically or open. Larger lesions greater than 3cm in diameter and 1cm in depth, can be managed by osteochondral allografts. The published mid- to long-term results for the knee have been encouraging. The results for the hip are early. To date we have performed this procedure on 16 patients. Surgical dislocation of the hip is carried out via a trochanteric osteotomy and the defect defined and trephined out. A press-fit fresh osteochondral allograft is inserted using the trephine technique. We have published our early results on a series of 8 patients with 5 good to excellent results, 1 fair results and 2 failures

Poly (vinyl alcohol) (PVA) hydrogel with high water content is one of the potential materials for artificial cartilage. In the previous study, the wear behavior of PVA hydrogel prepared by freeze-thawing (FT) method (PVA-FT gel) showed the excellent friction and wear property in simulated biological environment. However, the improvement of mechanical strength and wear resistance would be also needed for clinical application of PVA hydrogel as artificial cartilage. The different kind of physically-crosslinked PVA hydrogels prepared by cast-drying (CD) method (PVA-CD gel) and hybrid method of FT and CD (PVA-CD on FT hybrid gel) were also developed, and these two hydrogels have different mechanical properties and showed low friction compared with PVA-FT gel in saline. In this study, PVA hydrogel prepared by CD and hybrid methods were newly developed and friction and wear behavior of PVA-CD gel and PVA-CD on FT hybrid gel were evaluated in simulated biological environment. A sliding pair of an ellipsoidal reciprocating upper specimen of hydrogel and a flat stationary lower specimen of hydrogel was tested in reciprocating friction test. The thicknesses of PVA-CD gel and PVA-CD on FT hybrid gel were 2.0mm and 1.7mm, respectively. The applied load was 2.94 N. The sliding velocity was 20 mm/s and the total sliding distance was 1.5 km. In this study, solutions that contain hyaluronic acid, phospholipid and proteins were prepared as simulated synovial fluid and used as a lubricant for friction test. Molecular weight of sodium hyaluronate was 9.2×10. 5. L-alpha dipalmitoylphosphatidylcholine (DPPC) was selected as phospholipid constituent and was dispersed in saline as liposome. This liposomal solution was used as a base lubricant. Albumin and gamma-globulin, which are main protein constituents in natural synovial fluid, were used as additives as protein constituents. As shown in Fig.1, PVA-CD gel showed low friction such as below 0.02 at initial state of friction test. However, friction coefficient of PVA-CD gel rapidly increased and reached to about 0.5. In contrast, PVA-CD on FT hybrid gel kept low friction within the friction test. After friction test, many deep scratches were observed on the worn surface of PVA-CD gel (Figs. 2(a)-(c)). In contrast, the original surface structure of PVA-CD on FT hybrid gel almost remained while some scratches were observed (Figs. 2(d)-(f)). These results indicated that PVA-CD gel could show low friction but low wear resistance. The hybridization of FT and CD improved the wear resistance of PVA-CD gel. Therefore, the hybridization of FT and CD method is one of the prospective preparation methods of artificial cartilage with low friction and low wear. It is important to elucidate the mechanism of excellent lubricating property of PVA-CD on FT hybrid gel and develop the highly-functioned artificial hydrogel cartilage with low friction and high wear resistance

Total hip and knee joint prostheses composed of ultra-high molecular weight polyethylene (UHMWPE) and metal or ceramics have been widely applied. Efficacious treatments such as crosslinking, addition of vitamin E and phospholipid coating to UHMWPE have reduced wear and extended the life of joint prostheses. However, wear problems have not yet been completely solved for cases involving severe conditions, where direct contact can occur in mixed or boundary lubrication. In contrast, extremely low friction and minimum wear are maintained for a lifetime in healthy natural synovial joints containing articular cartilage with superior lubricity. Accordingly, joint prostheses containing artificial hydrogel cartilage with properties similar to those of articular cartilage are expected to show superior tribological functions. In establishing the function of artificial hydrogel cartilage as a novel material for joint prostheses, the tribological properties of hydrogel materials used and synergistic performance with synovia constituents are both important. In this study, the lubrication ability and wear resistance properties of poly(vinyl alcohol) (PVA) hydrogels were evaluated by differences in friction and wear properties in reciprocating tests lubricated with saline and simulated synovial fluid. Biphasic finite element (FE) analysis was applied to elucidate the role of biphasic lubrication mechanism in hydrogels. As biocompatible artificial hydrogel cartilage materials, three PVA hydrogels were prepared using the repeated freeze-thawing (FT) method, the cast-drying (CD) method and the hybrid method for laminated gel of FT on CD, which are physically crosslinked with hydrogen bonding but differ in terms of structure and mechanical properties. First the frictional behavior of the ellipsoidal PVA hydrogel specimens was examined in reciprocating tests against a glass plate, which corresponds to simplified knee prosthesis model (Fig.1), with a sliding speed of 20 mm/s under constant continuous loading. As shown in Fig.1, the three hydrogels exhibited different frictional behaviors in a saline solution. It is noteworthy that the hybrid gel maintained very low friction until the end of test. The CD gel showed slightly higher friction and a gradual increase. Meanwhile, the FT gel showed initial medium friction and a gradual increase. Time-dependent frictional behavior was clarified with biphasic lubrication mechanism via biphasic FE analysis. Contact surface observation showed minimal wear without scratches for hybrid gel in saline. Next, simulated synovial fluid composed of 0.5 wt% hyaluronic acid (HA, molecular weight: 920,000 Da), 1.4 wt% albumin, 0.7 wt% gamma-globulin and 0.01 wt% L-alpha dipalmitoylphosphatidylcholine (DPPC), was used to evaluate tribological performance of these gels in physiological condition. As shown in Fig.2, PVA hydrogels in simulated synovial fluid exhibited very low friction, with hybrid gel showing an extremely low friction coefficient of 0.003 in the test. These friction differences were sustained by biphasic FE analysis. Hybrid gel further showed very little wear (Fig.3), which is favorable in terms of hydrogel durability. These results indicate the importance of superior lubricity and wear resistance of PVA hybrid gel for the clinical application of artificial hydrogel cartilage in joint prostheses

Introduction. Some patients complain ingrown pain or discomfort after implanting Co-Cr conventional endprosthesis of the hip. Some of this complaint may be attributable for effect on cartilage metabolism. It have been reported that ceramic is bioinert for biological tissue. On the other hand, metal including cobalt-chrome (Co-Cr) have some detrimental effect on biological tissue. However, there is no report concerning acetabular cartilage metabolism after hip endprosthesis implantation. In the present study, we hypothesized that ceramic head have small detrimental effect on cartilage cell metabolism. Specific aim of the study is to compare the protein level of inflammation related cytokines, amount of hyaluronic acid (HA) in culture media, and cartilage mRNA expression in organ culture model of hip end prosthesis implanted using ceramic head and Co-Cr head. Materials and Methods. Six acetabulum of 3 matured crossbred pig (average weight: 36 +/− 3.6kg) was retrieved. Animal experiment was performed under the rules of ethical committee of animal experiment. Average diameter of pig acetabulum was 26.3 +/− 0.6 mm. Just after sacrifice, mechanical loading using Instron testing machine with 26mm diameter of Co-Cr in right hip and Ceramic heads in left hip was performed in culture media. Ten thousand cycles of cyclic compression and rotation load (1.5kN to 0.15kN of compression and 12 degrees of rotation) to cartilage was applied at 1Hz (Figure 1). Culture media was analyzed for protein levels of inflammation related cytokines and amount of HA. Relative quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) from acetabular cartilage was performed as previously reported using specific primer sets for type II collagen, aggrecan, TNF-alpha, Interleukine-1 and 6, and MMP-1, 3, 13. Results. IL-1 beta protein level from culture media was significantly higher in Co-Cr than that in Ceramic (155+/−25.2 pg/ml vs. 86.3+/−9.6 pg/ml respectively). MMP-3 protein level had tendency to be higher in culture media from Co-Cr than that from Ceramic (16.3+/−10.6 ng/ml vs. 10.0+/−0.1 ng/ml respectively, p<0.05), however there was no significant difference. There were no significant differences of protein levels from culture media in MMP-1, IL-1a, and TNF between two groups. Amount of HA from culture media of Co-Cr group was significantly higher than that from Ceramic group (337+/−38.4 mg/ml versus 257+/−11.1 mg/ml respectively, p<0.05). Type II collagen mRNA expression was 3 times higher in Ceramic group than that in Co-Cr group. IL-1 beta mRNA expression was 4 times higher in Co-Cr group than that in Ceramic group. Other gene expression had no significant differences. Discussion. The present study showed that Co-Cr affects cartilage metabolism than Ceramic. Co-Cr group had higher protein level and mRNA expression of inflammation related cytokine, IL-1 beta, and higher HA. Concerning the mRNA expression from cartilage, type II collagen was significantly higher in Ceramic group. It has been reported that HA level is high in osteoarthritic joint. These report and our results showed that ceramic head have small detrimental effect on cartilage cell metabolism. There are limitations of the present study. Firstly, the sample size is small. Secondly, we did not evaluate synovial membrane metabolism

In joint prostheses using ultra-high molecular weight polyethylene (UHMWPE) as bearing material, wear problems are not yet completely solved under severe conditions in various daily activities, although efficacious treatments such as crosslinking, addition of vitamin E and the grafting of phospholipid polymer improved the wear properties. In contrast, in healthy natural synovial joints possessing articular cartilage as biphasic bearing material lubricated with synovial fluid, minimal wear with extremely low friction has been maintained for a whole life. Therefore, the joint prosthesis with artificial hydrogel cartilage with similar properties to articular cartilage is expected to show superior tribological functions with very low friction and infinitesimal wear if the appropriate lubrication mechanism is actualized. In this study, the effectiveness of biphasic lubrication mechanism in hydrogel through significant load support by fluid phase is evaluated in finite element (FE) analysis for reciprocating motion. As biocompatible artificial hydrogel cartilage materials, two kinds of poly (vinyl alcohol) (PVA) hydrogels were prepared by the repeated freezing-thawing method and the cast-drying method, which are physically crosslinked with hydrogen bonding but different in structure and mechanical properties. To evaluate these time dependent behaviors of load-support ratio of fluid/solid phases and friction, two-dimensional biphasic FE analysis for cylindrical PVA hydrogel cartilage as 1.5 mm thick soft layer and radius of 5 mm was conducted under continuous loading of 0.2 N/mm by impermeable rigid plate in reciprocating motion in Fig. 1. The sliding speed is 4 mm/s for stroke of 8 mm at period of 4 s. A commercial package ABAQUS (6.8–4), which was appropriately evaluated for the biphasic FE analyses, was used in this study. The biphasic tissue was modeled by CPE4RP (four-node bilinear displacement and pore pressure, reduced integration with hour glass control) elements. The mechanical properties such as permeability, Young's modulus and Poisson ratio were estimated by curve fitting to stress relaxation behaviors in compression test. As indicated in Fig. 2, it is worth noting that the cast-drying PVA shows significant interstitial fluid pressurization compared with a repeated freezing-thawing PVA hydrogel at 292 s after start-up, where coefficient of friction for solid-to-solid was assumed as 0.2. Changes in friction for PVA hydrogels in reciprocating motion were estimated as shown in Fig. 3. In spite of high friction (0.2) for solid-to-solid, cast-drying PVA brought the gradual decreasing in friction, probably due to rising of load-support ratio by fluid phase from initial 74% to 80%. In human body, lubricating constituents in synovial fluids such as hyaluronic acid, proteins, glycoproteins and phospholipids can reduce the coefficient of friction for solid-to-solid. As suggested for low coefficient of friction for solid-to-solid as 0.01 in Fig. 3, rubbing friction is expected to be reduced to significantly low level. As described above, the effective biphasic lubrication can sustain low friction level and minimal wear in synergistic action with soft-elastohydrodynamic lubrication, hydration lubrication and boundary lubrication as a similar mechanism to natural cartilage in various daily activities. These results indicate the usefulness of artificial hydrogel cartilage for longer durability in joint prostheses for clinical application

The number of arthroplasties being undertaken is expected to grow year on year, and periprosthetic joint infections will be an increasing socioeconomic burden. The challenge to prevent and eradicate these infections has resulted in the emergence of several new strategies, which are discussed in this review.

Cite this article: Bone Joint J 2015;97-B:1162–9.