To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015-2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 12,156 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Aims

Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.

Aims

Socioeconomic and racial disparities have been recognized as impacting the care of patients with cancer, however there are a lack of data examining the impact of these disparities on patients with bone sarcoma. The purpose of this study was to examine socioeconomic and racial disparities that impact the oncological outcomes of patients with bone sarcoma.

Aims

The study aimed to determine whether the microRNA miR21-5p (MiR21) mediates temporomandibular joint osteoarthritis (TMJ-OA) by targeting growth differentiation factor 5 (Gdf5).

The superficial zone (SFZ) of articular cartilage has unique structural and biomechanical features, and is important for joint long-term function. Previous studies have shown that TGF-β/Alk5 signaling upregulating PRG4 expression maintains articular cartilage homeostasis. However, the exact role and molecular mechanism of TGF-β signaling in SFZ of articular cartilage homeostasis are still lacking. In this study, a combination of in vitro and in vivo approaches were used to elucidate the role of Alk5 signaling in maintaining the SFZ of articular cartilage and preventing osteoarthritis initiation.

Mice with inducible cartilage SFZ-specific deletion of Alk5 were generated to assess the role of Alk5 in OA development. Alterations in cartilage structure were evaluated histologically. The chondrocyte apoptosis and cell cycle were detected by TUNEL and Edu staining, respectively. Isolation, culture and treatment of SFZ cells, the expressions of genes associated with articular cartilage homeostasis and TGF-β signaling were analyzed by qRT-PCR. The effects of TGF-β/Alk5 signaling on proliferation and differentiation of SFZ cells were explored by cells count and alcian blue staining. In addition, SFZ cells isolated from C57 mice were cultured in presence of TGF-β1 or SB505124 for 7 days and transplanted subcutaneously in athymic mice.

Postnatal cartilage SFZ-specific deletion of Alk5 induced an OA-like phenotype with degradation of articular cartilage, synovial hyperplasia as well as enhanced chondrocyte apoptosis, overproduction of catabolic factors, and decreased expressions of anabolic factors in chondrocytes. qRT-PCR and IHC results confirmed that Alk5 gene was effectively deleted in articular cartilage SFZ cells. Next, the PRG4-positive cells in articular cartilage SFZ were significantly decreased in Alk5 cKO mice compared with those in Cre-negative control mice. The mRNA expression of Aggrecan and Col2 were decreased, meanwhile, expression of Mmp13 and Adamts5 were significantly increased in articular cartilage SFZ cells of Alk5 cKO mice. In addition, Edu and TUNEL staining results revealed that slow-cell cycle cell number and increase the apoptosis positive cell in articular cartilage SFZ of Alk5 cKO mice compared with Cre-negative mice, respectively. Furthermore, all groups of SFZ cells formed ectopic solid tissue masses 1 week after transplantation. Histological examination revealed that the TGF-β1-pretreated tissues was composed of small and round cells and was positive for alcian blue staining, while the SB505124-pretreated tissue contained more hypertrophic cells though it did stain with alcian blue.

TGF-β/alk5 signaling is an essential regulator of the superficial layer of articular cartilage by maintaining chondrocyte number, its differentiation properties, and lubrication function. Furthermore, it plays a critical role in protecting cartilage from OA initiation.

Aims

This study aimed to uncover the hub long non-coding RNAs (lncRNAs) differentially expressed in osteoarthritis (OA) cartilage using an integrated analysis of the competing endogenous RNA (ceRNA) network and co-expression network.

Osteoarthritis (OA) is traditionally believed to affect the osteochondral unit by wear-and-tear from the superficial zone to the deep zone of cartilage and extended to subchondral plate. Obesity is commonly considered as a risk of OA development and hence total knee replacement (TKR), but the mechanism remains unclear. We hypothesized that obesity accelerated OA development by deteriorating tidemarks and increasing bone remodelling. 616,495 cases of TKR for OA from Australia and British joint replacement registries were collected, and data indicated that patients with higher BMI had TKR at earlier age. Specifically, patients with BMI ≤25kg/m² showed 8 years younger than patients with BMI ≥40kg/m² (P<0.0001) when they received TKR. We next examined tibia plateaus of 88 knee OA patients by micro-CT and histomorphometry. Linear regression showed that less cartilage degradation was associated with increased BMI in the load-bear compartment (p<0.05), while 58.3% of patients with BMI≥40kg/m² demonstrated a clear anatomical separation close to tidemarks filled with fibrosis, erythrocytes and bone fragments (compared to BMI ≤25kg/m² group: 7.7%, p<0.01). In subchondral bone, elevated bone formation was associated with increased BMI, as higher thickness of osteoid (p<0.01), percent osteoid volume (p<0.01), percent osteoid surface (p<0.01) were found in obese patients. However, no alteration of bone resorption and microstructural parameters was found to be associated with BMI. We suspected that the abnormal loading in knee joint due to high BMI led to the direct deterioration of binding site of osteochondral unit, which might be the mechanism of the rapid progression in obesity-related OA.

Bone ingrowth is desired with uncemented hip implants. Infection is clearly undesirable. We have worked on developing a nanofiber coating for implants that would enhance bone formation while inhibiting infection. Few studies have focused on developing an implant surface nanofiber (NF) coating to prevent infection and enhance osseointegration by local drug release. In this study, coaxial doxycycline (Doxy)-doped polycaprolactone/polyvinyl alcohol (PCL/PVA) Nanofibers were directly deposited on the titanium (Ti) implant surface during electrospinning.

The interaction of loaded Doxy with both PVA and PCL NFs was characterized by Raman spectroscopy. The bonding strength of Doxy-doped NF coating on Ti implants was confirmed by a stand single-pass scratch test. The improved implant osseointegration by PCL/PVA NF coatings in vivo was confirmed by scanning electron microscopy, histomorphometry and micro computed tomography at 2, 4 and 8 weeks after implantation. The bone contact surface (%) changes of NF coating group (80%) is significantly higher than that of no NF group (< 5%, p<0.05). Finally, we demonstrated that Doxy-doped NF coating effectively inhibited bacterial infection and enhanced osseointegration in an infected (Staphylococcus aureus) tibia implantation rat model. Doxy released from NF coating inhibited bacterial growth up to 8 weeks in vivo. The maximal push-in force of Doxy-NF coating (38 N) is much higher than that of NF coating group (6.5 N) 8 weeks after implantation (p<0.05), which was further confirmed by quantitative histological analysis and micro computed tomography.

These findings indicate that coaxial PCL/PVA NF coating doped with Doxy and/or other drugs have great potential in enhancing implant osseointegration and preventing infection.

Summary

Collagen scaffolds loaded with mesenchymal stem cells accelerate neurological recovery in rat spinal hemisection.

Objective

The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing.

The purpose of this study was to analyze the long-term effect of arterial perfusion of drugs and bone marrow stromal cells (bMSCs) on osteonecrosis of femoral head (ONFH). From Jan 1997 to Mar 2004, one hundred and seventeen patients with ONFH were consecutively enrolled to receive a digital subtraction angiography (DSA) in arteriae circumflexa femoris medialis and arteriae circumflexa femoris lateralis. In DSA, a dosage of drugs (urokinase, salvia injection, and tetramethylpyrazine) and autologous bMSCs or only the drugs were perfused into the arteries. The morphological changes of the arteries in DSA after perfusion were recorded. Symptoms radiographs, and the Harris hip-rating score were determined preoperatively and at each follow-up examination at one month, six months, one year, 2 years and 5 years after the treatment. 83 patients were followed up for more than five years. The median follow-up period was 7.9 years.

After the drugs had been perfuse, the arteries became thicker, and more than 2 branches appeared in DSA. Five years after the operation, the Harris hip score of 32 patients (38 hips) treated by arterial perfusion of simplex drugs (group A) increased from 59.24±5.28 to 71.80±6.37 (p< 0.01), and the excellent and good rate of centesimal evaluation was 57.9%. The Harris hip score of 51 patients (59 hips) treated by arterial perfusion of drugs and autologous bMSCs (group B) increased from 59.52±4.85 to 78.29±6.05 (p< 0.01), and the excellent and good rate was 78.0% which was significantly higher than that of group A (p=0.035). Since two years after operation, the Harris hip score of group A was significantly higher than that of group B (p< 0.01).

Among the patients in group B, the rate of excellent and good in early stages (˜,˜ a and ˜ b according to Ficat classifying, 50 hips) was 84.0%, which was better than the rate in the terminal stage (Ficat III, 9 hips, the excellent and good rate was 44.4%)(p = 0.028), and the rate of excellent and good in low age group (< 40 years, 33 hips) was also better than that in high age group (≥ 40 years, 26 hips)(p=0.038).

We conclude that arterial perfusion of drugs and autologous bMSCs treating osteonecrosis of femoral head is safe and effective. The long-term therapeutic effect is more satisfactory than that of simplex arterial perfusion of drugs.

Synthetic biodegradable polymers have been utilized increasingly in pharmaceutical, medical and biomedical engineering. Control of the interaction of living cells and biomaterials surfaces is one of the major goals in the design and development of new polymeric biomaterials in tissue engineering.

In this study, a novel amphiphilic tri-block copolymer, methoxy-terminated poly (ethylene glycol) (MPEG) – polyL-lactide (PLLA) – polylysine (PLL) was synthesized. Various molecular compositions of tri-block copolymers were prepared via optimising the parameters and characterized through Nuclear Magnetic Resonance and Gel Permeation Chromatography. The tri-block copolymer was then mixed with high molecular weight PLLA to form a flat film. The surface properties measured by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy demonstrated high content of the PLL on the surface of PLLA film, which indicated self-segregation of MPEG-b-PLLA-b-PLL on PLLA surface. No cytotoxicity was detected in triblock copolymers, and compared to pure PLLA and diblock copolymers, the triblock copolymers were much more effective for cell adhesion and proliferation. It was noted that the hydrophilic chain of PEG and PLL stretched out and formed an outer layer, especially under the aqueous environment, which resulted in enhanced cell attachment and proliferation. The self-segregation behaviour of MPEG-b-PLLA-b-PLL triblock copolymer shows a potential application in scaffold preparation of tissue engineering.

Interactions between cells and polymers are mediated by proteins, which are either secreted by cells and immobilized on the biomaterial surface, or absorbed from the medium. Poly (lactic acid) (PLA) is widely used in tissue engineering as a scaffold material, however anchorage-dependent cells such as osteoblasts do not attach, grow, and differentiate well on a hydrophobic surface. In this study, a hydrophilic polymer-poly (ethylene glycol) (PEG) was used to develop diblock polymers, Methoxy-terminated poly (ethylene glycol)-Poly (lactic acid) (MPEG-PLA) to investigate cell-biomaterial interactions. Osteoblasts were cultured on different composition of PEG-PLA films in serum free or serum condition. Lactate dehydrogense (LDH) assay was used to assess the cytotoxicity of the copolymers and cell attachment and proliferation on the polymer surfaces; furthermore cell morphology was visualized by Crystal Violet stain.

The results showed that MPEG-PLA films induced early osteoblast attachment in serum free condition and the higher content of PEG in the MPEG-PLA films the more cell attachment was noticed. No significant difference of cell attachment was observed on MPEG-PLA films between serum free and 10% serum culture condition. Crystal Violet stain demonstrated the same trend in the cell-spreading characteristics on the polymer surface.

In conclusion MPEG-PLA copolymer can enhance osteoblast attachment under serum-free condition, which implies a potential application in cell delivery therapy due to the restriction in animal products for human therapeutically goods.

Introduction Anterior column reconstruction and fusion remains the gold standard of treatment for a number of spinal pathologies. One of the challenges of interbody fusions cages is the footprint of the cage reducing the surface area of endplate available for fusion. Biodegradable polymer implants will over time present a greater area for fusion and may help to reduce problems such as stress shielding, particulate debris and retained foreign body response. Resorbable cages have been have been prepared from a number of different materials, including inorganic composites (eg hydroxyapatite / tricalcium phosphate) and polymers (Poly L-lactide-co-D,L-lactide (PDLLA)). However all of the current options for interbody fusion have reported deficiencies or complications. The synthesis, mechanical properties, and degradation behaviour of two novel biopolymers are presented and the applicability for use as materials in interbody fusion devices is discussed.

Methods Methacrylated adipic anhydride (MAA) and methacrylated sebacic anhydride (MSA) pre-polymers were synthesized by melt condensation. Conversion of the acid to the anhydride was confirmed using 1H nuclear magnetic resonance (NMR) (Bruker, Alexandria, NSW) and FT- Infrared spectroscopy (Nicolet, Waltham MA). These pre-polymers were subsequently co-polymerized with methyl methacrylate (MMA) and 0.25 wt% benzoyl peroxide at 65oC for 16hrs and post-cured at 120oC under vacuum for 2 hrs to form biodegradable networks. The co-polymerization behaviour was monitored by FT-Raman spectroscopy. The compressive mechanical properties of the polymer were determined using an Instron 5567 (Bayswater Vic.). The polymer networks were degraded in phosphate buffered saline (PBS) with various amounts of MAA and MSA.

Results The formation of the pre-polymer was confirmed with the observation of NMR peaks at 5.8 and 6.2 ppm and FT-IR peaks at 1637cm-1. Copolymerization was followed with consecutive FT-IR acquisitions with 100% conversion achieved between 10 and 30 hrs depending on the ratio of MMA to MSA or MAA. Increasing the fraction of methacrylated anhydride slowed the reaction rate.

The compressive strength of the MAA and MSA based copolymers was measured as a function of anhydride concentration. Compressive strength for MMA increased (90±9 to 140±10 Mpa) in an approximately linear manner for MAA concentrations from 10 to 40 wt.% but decreased markedly for MAA concentration of 45% (62±14 Mpa). The compressive strength of MSA decreased exponentially for concentrations ranging from 10 to 45 wt.% (140±18 to 39±1 Mpa).

Discussion The use of poly-L-lactic acid in lumbar interbody cages has been shown to be mechanically feasible with the mechanical strength of the cage material reported to be 93 Mpa (1). The material described here has controlled mechanical properties in the required range as well as a degradation behaviour that lends itself better to spinal applications than current materials

Introduction and Aims: While successful long-term results have been shown for ligament reconstruction–tendon interposition arthroplasty for treatment of thumb basal joint osteoarthritis, the need for invasive ligament reconstruction has not been established. In this study we describe long-term results utilising the technique of tendon interposition arthroplasty with dynamic tendon transfer and capsulorrhaphy.

Method: Twenty-four thumbs (21 patients) were evaluated at an average of 7.1 years (1.8–19.5 years) post-procedure. Capsulorrhaphy was performed utilising APL tendon slips where tissue was insufficient. The APB origin was advanced via tendon transfer (FCR to APB), providing a stabilising abductor moment. Subjective assessment was performed using Visual Analogue Scores (VAS), Disabilities of Arm, Shoulder, Hand (DASH) scores, and patient satisfaction scales. Objective assessment included post-operative range of motion (ROM), grip/pinch strength, and radiographs for interposition arthroplasty height.

Results: Twenty of 21 patients (95%) were satisfied and described results as either good or excellent. Twenty of 21 patients (95%) would undergo surgery again. Mean VAS was 8.7 at rest and 10.2 with activity (0, no pain; 100, maximum pain). Mean DASH score was 16.9 (range from 0, no difficulty performing daily tasks to 100, unable to perform daily tasks). ROM, grip, lateral and tip pinch strengths were comparable with those of the contralateral thumb. AP radiographs showed preservation in 12 of 12 patients (100%). Fourteen of 21 patients received the procedure on their dominant hand.

Conclusion: Treatment of basal joint osteoarthritis with our technique provided stable and functional reconstructions, resulting in excellent pain relief. Results were comparable to, or better than, those previously cited in the literature for alternative procedures. These results suggest that dogma requiring static ligament reconstruction or suspension may need to be re-evaluated.

Introduction and Aims: The volar carpal ganglion (VCG) is a common benign tumor of the hand complicated by multiple recurrences with conventional treatment. Despite being a common condition, we know of no report describing post-operative functional outcome. We evaluated functional outcome, pain, scarring, and recurrence after VCG excision in the last 15 years.

Method: Twenty-eight patients were considered for inclusion in this study. All patients had been surgically treated for volar carpal ganglia in the last 15 years. Of these, 16 were available for follow-up after exclusion of patients who had since deceased, moved, or were otherwise lost to follow-up. Mean follow-up period was 55 months (nine–135 months). Functional outcome of the upper extremity was evaluated using the standard DASH questionnaire. DASH scores can range from zero (no difficulty in performing daily tasks) to 100 (unable to perform daily tasks). Pain, scarring, and recurrence were also assessed.

Results: Sixteen patients who underwent surgical excision of their recurrent volar carpal ganglions were available for follow-up at the time of the study. They included six men and 10 women, with a mean age of 47 (range 11–70 years). The duration of symptoms prior to excision ranged from two to 50 months. Pain was the main reason for surgery while one patient reported that surgery was performed for cosmetic reasons. There were eight patients in the nine-month to three-year follow-up period and the average DASH score was 7.6. The four patients in the three to five-year follow-up period had an average DASH of 8.1. The four patients in the five plus years of follow-up had an average DASH of 1.7. The improvement in functional outcome correlated with time since surgery, however these differences were not statistically significant. Two of the 16 patients had recurrences within six months after excision. Increased pain was reported in these patients only. No patients complained of significant scarring post-operatively.

Conclusion: Multiple treatment modalities including aspiration and surgery are discussed in the literature with great outcome variability. Our series is the first long-term functional assessment after VCG excision. Thus, surgery is an option for treatment of this common condition as evidenced by low recurrence and DASH scores and high patient satisfaction.

Injection of PMMA bone cement into fractured vertebral bodies has been used clinically and proved to be effective. However, there are concerns about thermal injury to the cord and interferece of bone remodling .The purpose of this study is to use the biodegradable bone substitute as an alternative for augumentation of fractured vertebral bodies .

Material and Methods: From April 1998 to January 2000, 10 patients(Nine females and one male, age from 55 to 74 years) with osteoporotic compression fractures were retrospectively reviewed. The level of compression fracture mostly occurred at T12-L1 (Nine of ten cases). Eight of the ten cases were osteonecrosis of vertebral body with vaccum phenomenon. While other two cases had gross kyphotic deformity. Surgical indications for these ten patients include back pain, progressive kyphosis and failure of conservative medical treatment. (No neurological deficits were noted in all ten cases.) All ten cases underwent posterior instrumentation with vertebroplasty (Bipedicle impaction of osteoset and iliac bone autograft). The anterior body height and the kyphotic angle were measured preoperatively and postoperatively. The fusion mass was observed and followed up with T-L spine AP and Lateral X-ray regularly.

Result: The anterior body height increased over 50% in all cases in this series. The average correction of kyphosis angle is 10 degree. Stable arthrodesis with obvious fusion mass occurred in all patients under X-ray image. Postoperative pain relief were noted in all ten patients. No major complications were related to this procedure.

Conclusion: This preliminary study shows that vertebroplasty using osteoconductive biodegradable bone substitute and osteoinductive iliac bone autograft in osteoporotic compression fracture with osteonecrosis is feasable and effective. The technique might also provide an alternative for treatment of osteoporotic compression fractures instead of PMMA bone cement.

Background Data: Postoperative spondylothesis had been noted for many years, first reported by White in 1977. Biomechanic effect of the facetectomy was reported by Abumi in 1992. There were few reports about the results of surgical treatment for postoperative spondylolisthesis.

Purpose: To assess the outcome of surgical treatment for postoperastive spondylolisthesis and examine the factors that might correlate with postoperative spondylolisthesis.

Materials and Methods: This study retrospectively reviewed twenty seven patients (eleven male and sixteen female), from 1979 to 1996, who received pedicle screws instrumentation and posterolateral fusion for postoperative spondylolisthesis. Average age was 57.3 years old (from 36.6 to 79.5 years old). Average follow-up time was 40.0 months (from 24 months to 72 months). The grade of fcetectomy, percentage of vertebral slipping, and disc narrowing was checked by plain X-ray. End results were assessed using the modified Stauffer-Coventry’s evaluation criteria.

Results: The mean period of postoperative instability was 49.3 months (from 6 months to 141 months) in whole group, 43.7 months (from 6 months to 129 months) in laminectomy group, 43.4 months (from 17months to 82 months) in laminectomy and disectomy groups, and 74.6 months (13 months to 141 months) in disectomy group. After an average follow-up period of 40 months, 29.6 % of patients had excellent results, 44.5% had good results, and 25.9 % had fair result. No complication was found in this study.

Conclusions: Pedicle screw instrumentation with posterolateral fusion can get satisfactory result for postoperative spondylolisthesis.