Miniscrew implants (MSIs) are widely used to provide absolute anchorage for the orthodontic treatment. However, the application of MSIs is limited by the relatively high failure rate (22.86%). In this study, we wished to investigate the effects of amorphous and crystalline biomimetic calcium phosphate coating on the surfaces of MSIs with or without the incorporated BSA for the osteointegration process with an aim to facilitate the early loading of MSIs.

Amorphous and crystalline coatings were prepared on titanium mini-pin implants. Characterizations of coatings were examined by Scanning electron microscopy (SEM), Confocal laser-scanning dual-channel-fluorescence microscopy (CLSM) and Fourier-transform infrared spectroscopy (FTIR). The loading and release kinetics of bovine serum albumin (BSA) were evaluated by Enzyme linked immunosorbent assay (ELISA). Activity of alkaline phosphate (ALP) was measured by using the primary osteoblasts. In vivo, a model of metaphyseal tibial implantation in rats was used (n=6 rats per group). We had 6 different groups: no coating no BSA, no coating but with surface adsorption of BSA and incorporation of BSA in the biomimetic coating in the amorphous and crystalline coatings. Time points were 3 days, 1, 2 and 4 weeks. Histological and histomorphometric analysis were performed and the bone to implant contact (BIC) of each group was compared.

In vitro, the incorporation of BSA changed the crystalline coating from sharp plates into curly plates, and the crystalline coating showed slow-release profile. The incorporation of BSA in crystalline coating significantly decreased the activity of ALP in vitro. In vivo study, the earliest significant increase of BIC appeared in crystalline coating group at one week.

The crystalline coating can serve as a carrier and slow release system for the bioactive agent and accelerate osteoconductivity at early stage in vivo. The presence of BSA is not favorable for the early establishment of osteointegration.

Osteoporotic fracture has become a major problem in ageing population and often requires prolonged healing time. Low Intensity Pulsed Ultrasound (LIPUS) can significantly enhance fracture healing through alteration of osteocyte lacuno-canalicular network (LCN). DMP1 in osteocytes is responsible for maintaining LCN and mineralisation. This study aims to investigate osteocyte-specific DMP1's role in enhanced osteoporotic fracture healing in response to mechanical stimulation.

Bilateral ovariectomy was performed in 6-month-old female SD rats to induce osteoporosis. Metaphyseal fracture was created at left distal femur using oscillating micro-saw. Rats were randomised to groups: (1) DMP1 KD, (2) DMP1 KD + LIPUS, (3) Control, or (4) Control + LIPUS, where KD stands for knockdown by injection of shRNA into marrow cavity 2 weeks before surgery. Assessments included weekly radiography, microCT and immunohistochemistry on DMP1, E11, FGF23 and sclerostin.

DMP1 KD significantly impaired LIPUS-accelerated fracture healing when comparing KD + LIPUS group to Control + LIPUS group. The X-ray relative opacity showed less tissue growth at all timepoints (Week 1, 3 & 6; p=0.000, 0.001 and 0.003 respectively) and the bone volume fraction was decreased after DMP1 KD at Week 3 (p=0.006). DMP1 KD also significantly altered the expression levels of osteocyte-specific DMP1, E11, FGF23 and sclerostin during healing process.

The lower relative opacity and bone volume fraction in DMP1 KD groups indicated that knockdown of DMP1 was associated with poorer fracture healing process compared to non-knockdown groups. The similar results between knockdown group with and without LIPUS showed that blockage of DMP1 would negate LIPUS-induced enhancement on fracture healing.

Acknowledgment: General Research Fund (Ref: 14113018)

Aims

Degenerative cervical spondylosis (DCS) is a common musculoskeletal disease that encompasses a wide range of progressive degenerative changes and affects all components of the cervical spine. DCS imposes very large social and economic burdens. However, its genetic basis remains elusive.

Aims

We have previously reported cryoablation-assisted joint-sparing surgery for osteosarcoma with epiphyseal involvement. However, it is not clear whether this is a comparable alternative to conventional joint arthroplasty in terms of oncological and functional outcomes.

Aims

Restoration of proximal medial femoral support is the keystone in the treatment of intertrochanteric fractures. None of the available implants are effective in constructing the medial femoral support. Medial sustainable nail (MSN-II) is a novel cephalomedullary nail designed for this. In this study, biomechanical difference between MSN-II and proximal femoral nail anti-rotation (PFNA-II) was compared to determine whether or not MSN-II can effectively reconstruct the medial femoral support.

Aims

Currently, there is no single, comprehensive national guideline for analgesic strategies for total joint replacement. We compared inpatient and outpatient opioid requirements following total hip arthroplasty (THA) versus total knee arthroplasty (TKA) in order to determine risk factors for increased inpatient and outpatient opioid requirements following total hip or knee arthroplasty.

Aims

Currently, the US Center for Medicaid and Medicare Services (CMS) has been testing bundled payments for revision total joint arthroplasty (TJA) through the Bundled Payment for Care Improvement (BPCI) programme. Under the BPCI, bundled payments for revision TJAs are defined on the basis of diagnosis-related groups (DRGs). However, these DRG-based bundled payment models may not be adequate to account appropriately for the varying case-complexity seen in revision TJAs.

Aims

The aim of this study was to clarify the factors that predict the development of avascular necrosis (AVN) of the femoral head in children with a fracture of the femoral neck.

Aims

The aim of this study was to investigate the differences in 30-day outcomes between patients undergoing revision for an infected total hip arthroplasty (THA) compared with an aseptic revision THA.

Objectives

Many in vitro studies have investigated the mechanism by which mechanical signals are transduced into biological signals that regulate bone homeostasis via periodontal ligament fibroblasts during orthodontic treatment, but the results have not been systematically reviewed. This review aims to do this, considering the parameters of various in vitro mechanical loading approaches and their effects on osteogenic and osteoclastogenic properties of periodontal ligament fibroblasts.

Aging has been associated with decreases in muscle strength and bone quality. In elderly patients, paravertebral muscle atrophy is accompanied by vertebral osteoporosis. The purpose of this study was to use paravertebral injection of botulinum toxin-A (BTX) to investigate the effects of paravertebral muscle atrophy on lumbar vertebral bone quality. Forty 16-week-old female SD rats were randomly divided into four groups: (1) a control group (CNT); (2) a resection of erector spinae muscles group (RESM); (3) a botulinum toxin-A group (BTX) that was treated with local injection of 5U BTX into the paravertebral muscles bilaterally; and (4) a positive control group (OVX) that underwent bilateral ovariectomy. At 3 months post-surgery the lumbar vertebrae (L3 – L6) were collected. The BMDs of the RESM and BTX groups were significantly lower than that of the CNT group (P < 0.01). Micro-CT scans showed that rats in the three experimental groups had fewer trabeculae and trabecular connections than rats in the CNT group. The bone loss trend of the trabecular networks was most obvious in the OVX rats. Vertebral compression testing revealed that the three experimental groups had significantly lower maximum load, energy absorption, maximum stress, and elastic modulus values than the CNT group (P < 0.01), and these parameters were lowest in the OVX group (P < 0.05). Our results demonstrate that the new paravertebral muscle atrophy model using local BTX injection causes sufficient muscle atrophy and dysfunction to result in local lumbar vertebral bone loss and quality deterioration.

BACKGROUND

Diffuse noxious inhibitory control (DNIC) is impaired in people with chronic pain such as knee osteoarthritis (KOA), which may predict the risk of acute-to-chronic pain transition. Electroacupuncture (EA) is effective in relieving pain in patients with KOA. However, whether EA may inhibit acute-to-chronic pain transition of KOA has not been systematically examined.

Diffuse noxious inhibitory control (DNIC) works through the “pain-inhibits-pain” principle in which an additional painful (conditioned) stimulus can suppress the initial experienced pain through the descending and inhibiting pathways. Painful stimulation produced less pain inhibition in patients with knee osteoarthritis patients (KOA) than in controls, suggesting an impaired DNIC function and a loss of endogenous pain modulation. Electroacupuncture (EA) is widely used to treat acute pain associated with KOA, but the available evidence of its benefit on chronification of acute pain is scarce.

This is a single-arm clinical study aims to evaluate the effect of EA on the chronification of pain associated with KOA and provide a profile of various cytokines underlying the pathogenesis of KOA. Participants are recruited through hospital-based recruitment and advertisements, diagnosis was based upon the criteria formulated by the American College of Rheumatology. Each participant was administered with EA (2 mA < current < 5 mA) at the ipsilateral EX-LE5, ST35, ST34 and SP10 for two weeks (once a day, 30 minutes per session, in 5 sessions per week). Visual Analog Scale (VAS), DNIC function, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Numerical Rating Scale (NRS), Emotional Scale (ES) and Present Pain Intensity (PPI) are evaluated before treatment and after 5 to 10 sessions of treatment. Cytokines including GRO, TNF-α, VEGF, IP-10, IL-1β, IL-17, IL-8, MCP-1 and IL-10 levels in plasma were measured using a Human Cytokine/Chemokine Magnetic Bead Panel on MAGPIX instrument before and after two weeks of treatment.

A total of 39 patients with KOA were enrolled in our study (age: 63.46±9.89 years; height: 1.63±0.07 m; BMI: 22.83±2.89), all of them completed the trial. After 5 sessions of EA treatment, a significant decrease of VAS, WOMAC scores, NRS, ES and PPI was detected, but no significant difference in DNIC was observed. After two weeks' treatment, all clinical parameters (VAS, DNIC, WOMAC, NRS, ES, PPI) reduced significantly when compared with baseline; GRO, IL-17A, IL-1b, IL-8, MCP-1, TNF-a, VEGF levels in plasma reduced significantly while IL-10 and IP-10 concentrations were elevated.

This study appeared to provide evidence that EA was effective in improving chronic pain associated with KOA through repairing the impaired DNIC function and down-regulation of OA detrimental cytokines. A randomized controlled prospective study with large sample size is required to clarify the effect of EA in reversing the chronification of pain in KOA.

Objectives

To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention.

In a rabbit model we investigated the efficacy of a silk fibroin/hydroxyapatite (SF/HA) composite on the repair of a segmental bone defect. Four types of porous SF/HA composites (SF/HA-1, SF/HA-2, SF/HA-3, SF/HA-4) with different material ratios, pore sizes, porosity and additives were implanted subcutaneously into Sprague-Dawley rats to observe biodegradation. SF/HA-3, which had characteristics more suitable for a bone substitite based on strength and resorption was selected as a scaffold and co-cultured with rabbit bone-marrow stromal cells (BMSCs). A segmental bone defect was created in the rabbit radius. The animals were randomised into group 1 (SF/HA-3 combined with BMSCs implanted into the bone defect), group 2 (SF/HA implanted alone) and group 3 (nothing implanted). They were killed at four, eight and 12 weeks for visual, radiological and histological study.

The bone defects had complete union for group 1 and partial union in group 2, 12 weeks after operation. There was no formation of new bone in group 3. We conclude that SF/HA-3 combined with BMSCs supports bone healing and offers potential as a bone-graft substitute.

We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant.

The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken.

No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006).

Introduction An approximation of normal knee kinematics after knee replacement may improve knee function and implant fixation and reduce wear of the prosthesis. This study describes the knee joint kinematics after unicondylar knee arthroplasty (UKA) in general, and compares the Miller-Glante (MG, fixed bearing) and Oxford (mobile bearing) implants in particular.

Methods Twenty-two knees in 17 patients (11 males, six females, mean age of 69.7 yrars) were randomized into MG (11 knees) or Oxford (11 knees). No clinical complications or signs of loosening were observed. At the one year follow-up, RSA (Radiosterometry) x-rays were taken by using two x-ray tubes positioned at knee level and exposing the knee simultaneously from the side. Four pairs of weight bearing x-ray were obtained at zero degrees, 30°, 60°, 90° of knee flexion, with zero as reference position. Tibial rotation, rollback, translation of tibia-femur contact point, and the bearing movement were analyzed using UmRSA software.

Results With the MG implant, the tibia internally rotated 3.0°, 3.0°, and 4.2° respectively at 30°, 60°, and 90° of flexion, while with the Oxford implant, the tibia internally rotated 4.3°, 7.6°, and 9.5° respectively at 30°, 60°, and 90°. No significant difference was found between the two groups (P> 0.05, Repeated-measures ANOVA). The medial femoral condyle moved backward (1.8 and 1.5 mm respectively in MG and Oxford) from zero degrees to 30° of flexion. At 60°, it moved anteriorly in both knees, in MG to 0.9 mm anteriorly and in Oxford to 0.6 mm posteriorly to the reference position. At 90° the condyle moved 4.2 mm (MG) and 0.7 mm (Oxford) anteriorly to the reference position. No significant difference between the groups (P> 0.05). The femur-tibia contact point in MG moved anteriorly 2.8, 5.1, and 3.9 mm, respectively at 30°, 60°, and 90° of flexion, whereas the contact point in Oxford moved posteriorly 2.6, 1.8, 2.4 mm respectively at 30°, 60°, and 90°. A significant difference was found between the groups (P=0.003). The bearing in the Oxford implant moved backward of 2.2, 2.0, and 0.9 mm respectively at 30°, 60°, and 90° of knee flexion.

Conclusions The in-vivo weight bearing 3D knee kinematics after UKA with fixed or mobile bearing was described. In MG the medial femoral condyle moved forward with knee flexion, whereas in Oxford it moved backward together with the bearing, which is closer to normal knee kinematics.

Introduction Impaction grafting in revision hip arthroplasty has now been used with a number of cemented stem designs. Follow-up has been short/intermediate with variable results due to pronounced stem subsidence and incomplete cement mantles. This study investigated the performance of a cementless, HA-coated stem used with the impaction grafting technique.

Methods We performed revision hip arthroplasty on a series of 16 stems for mechanical loosening (majority type II) in 14 patients (mean age 64 years). An uncemented Anatomic® stem was inserted into a neomedullary canal of impacted fresh frozen allograft bone. Stem migration was assessed with RSA. Graft and host cortical bone remodeling were evaluated radiographically as was the quality of the impaction grafting and amount of radiographic bone ingrowth. Bone mineral density (BMD) was assessed with DEXA at two and 10 years. Harris Hip Score was recorded for clinical assessment.

Results At six months the stems had subsided 0.78 mm (−7.78 – 0.22). Thereafter, the majority stabilized (6 months vs. 12 years: p=0.3). The graft had a homogenous distribution proximally, but to a lesser extent distally. Remodeling of graft was frequently seen at two years, especially proximally. There were no signs of graft resorption and no change in BMD in any Gruen zone between two and 10 years (P=0.15 – 0.54). About one third of patients had evidence of cortical restitution. In most cases there were no radiolucencies at all between the HA-fiber mesh and the bone. Slight cortical erosion at the stem tip was observed in nine cases but none progressed after two years. These parameters (remodeling, ingrowth and radiolucencies) changed minimally between the two and 12 years. At two years, the Harris Hip (50 to 85) and pain scores (20 to 40) had increased (p = 0.001). Thereafter the scores remained stationary. One hip dislocated during the first year. Heterotopic ossification occurred in three cases. One case underwent two stage revision at 30 months for late infection. One fracture was detected post-operatively. This stem subsided 16.2 mm at two years requiring revision. One patient died due to unrelated causes. Early migration was seen. Radiographs suggest much of the graft was substituted with living bone with no deterioration between two and 12 years.

Conclusions Our findings are sufficiently encouraging to initiate trials of uncemented stems with extended HA coatings.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.

Introduction Wear particle induced osteolysis is regarded as the main reason for aseptic loosening of hip replacements. Crosslinked polyethylene show extremely low wear in lab studies and is routinely used today, though with very little clinical testing. We report wear, migration and function for uncemented cups with a crosslinked poly.

Methods Twelve hips in 12 patients with mean age of 70 years were operated with uncemented cups (Reflection), cemented stems and metal heads. Five Mrad cross linked liners annealed below melt temperature were used in all hips (XLPE, Smith & Nephew). Tantalum markers were inserted in liners and acetabular bone for RSA measurements and migration and wear measured over two years. The result was compared to matched controls from a study of 80 cups with the same implant and non cross linked poly, operated by the same surgeon. X-rays, WOMAC and Sf-36 were performed pre-operatively and at two years.

Results The mean proximal head penetration at two months was 0.09 mm. This was thought to be mainly due to the creep of the polyethylene and was equal to “normal” poly. At the one year follow-up the mean proximal wear had increased with 0.02 mm and at two years 0.03 mm. This compares with the 0.33 mm recorded for the old poly (p=0.001, Mann Whitney U test.). The cups migrated 0.2 mm proximally and showed a normal migration profile, comparable to the cups with non cross-linked poly. The accuracy of measuring proximal wear, in this study, was found to be 0.07 mm (95% CI). No differences in radiolucent lines or clinical scores were found.

Conclusions The first two years proximal wear was 0.03 mm compared to the 0.33 mm found for non crosslinked poly. This is a reduction with 90% which certainly looks promising.

Introduction Debonding at the cement-prosthesis interface leading to stem movement and abrasion, has been proposed as initiating events in aseptic loosening of cemented total hip arthroplasties. A polished tapered or an absolutely stable stem possibly minimises this risk. This study evaluated a cemented, precoated femoral stem for stable fixation.

Methods The study included 24 patients, mean age of 64 years (48 to 78) undergoing single total hip arthroplasty for osteoarthritis. All were treated with cemented Definition (Stryker) stems which are straight, chromium-cobalt, with an integrated proximal polymethylmethacrylate mantle. One surgeon using fourth generation cementation techniques performed all surgeries. UHMWPE cups and Zirconia heads were used. At the time of surgery, tantalum markers were inserted into the femur, cement and stem for Radiostereometric analysis (RSA) of migration. Measurements were performed at two, 12 and 24 months intervals. Standard radiographs and Harris Hip Scores were obtained post-operatively and at two years.

Results During the first two years post-operatively the stems were shown to be absolutely fixed within the cement mantle and the mantle itself stable with the femur. At two years the mean subsidence of the stem in relation to the femur was 0.00 mm (SD 0.1), while the cement mantle subsided 0.2 mm (SD 0.2) in relation to the femur. The femoral head mean rotation was 0.02 retroversion. Postoperative radiolucent lines of > 1 mm where present in a mean of 1.4% (0 to 5%) of the cement-bone interfaces. This remained unchanged at two years (0 to 3%). Stems were in average positioned 0.8 in varus (1.2 valgus to 4.0 varus). Harris Hip Scores improved from a mean of 46 (23 to 68) pre-operatively to 93 (57 to 100) at two years.

Conclusions This is the first stem where no migration could be detected during the first two years. These results so far indicate good long-term performance of this precoated stem.