Objectives. Malalignment of the tibial component could influence the long-term survival of a total knee arthroplasty (TKA). The object of this study was to investigate the biomechanical effect of varus and valgus malalignment on the tibial component under stance-phase gait cycle loading conditions. Methods. Validated finite element models for varus and valgus malalignment by 3° and 5° were developed to evaluate the effect of malalignment on the tibial component in TKA. Maximum contact stress and contact area on a polyethylene insert, maximum contact stress on patellar button and the collateral ligament force were investigated. Results. There was greater total contact stress in the varus alignment than in the valgus, with more marked difference on the medial side. An increase in ligament force was clearly demonstrated, especially in the valgus alignment and force exerted on the medial collateral ligament also increased. Conclusion. These results highlight the importance of accurate surgical reconstruction of the coronal tibial alignment of the knee joint. Varus and valgus alignments will influence wear and ligament stability, respectively in TKA. Cite this article: D-S. Suh, K-T. Kang, J. Son, O-R. Kwon, C. Baek, Y-G. Koh. Computational study on the effect of malalignment of the tibial component on the biomechanics of total knee arthroplasty: A Finite Element Analysis. Bone Joint Res 2017;6:623–630. DOI: 10.1302/2046-3758.611.BJR-2016-0088.R2

Large bone defects remain a tremendous clinical challenge. There is growing evidence in support of treatment strategies that direct defect repair through an endochondral route, involving a cartilage intermediate. While culture-expanded stem/progenitor cells are being evaluated for this purpose, these cells would compete with endogenous repair cells for limited oxygen and nutrients within ischaemic defects. Alternatively, it may be possible to employ extracellular vesicles (EVs) secreted by culture-expanded cells for overcoming key bottlenecks to endochondral repair, such as defect vascularization, chondrogenesis, and osseous remodelling. While mesenchymal stromal/stem cells are a promising source of therapeutic EVs, other donor cells should also be considered. The efficacy of an EV-based therapeutic will likely depend on the design of companion scaffolds for controlled delivery to specific target cells. Ultimately, the knowledge gained from studies of EVs could one day inform the long-term development of synthetic, engineered nanovesicles. In the meantime, EVs harnessed from in vitro cell culture have near-term promise for use in bone regenerative medicine. This narrative review presents a rationale for using EVs to improve the repair of large bone defects, highlights promising cell sources and likely therapeutic targets for directing repair through an endochondral pathway, and discusses current barriers to clinical translation. Cite this article: E. Ferreira, R. M. Porter. Harnessing extracellular vesicles to direct endochondral repair of large bone defects. Bone Joint Res 2018;7:263–273. DOI: 10.1302/2046-3758.74.BJR-2018-0006

Aims

The aim of this meta-analysis is to assess the association between exchange of modular parts in debridement, antibiotics, and implant retention (DAIR) procedure and outcomes for hip and knee periprosthetic joint infection (PJI).

Aims

The current study aimed to compare robotic arm-assisted (RA-THA), computer-assisted (CA-THA), and manual (M-THA) total hip arthroplasty regarding in-hospital metrics including length of stay (LOS), discharge disposition, in-hospital complications, and cost of RA-THA versus M-THA and CA-THA versus M-THA, as well as trends in use and uptake over a ten-year period, and future projections of uptake and use of RA-THA and CA-THA.

Aims

This study investigates the effects of intra-articular injection of adipose-derived mesenchymal stem cells (AdMSCs) and platelet-rich plasma (PRP) on lameness, pain, and quality of life in osteoarthritic canine patients.

Stress shielding resulting in diminished bone density following total knee replacement (TKR) may increase the risk of migration and loosening of the prosthesis. This retrospective study was designed to quantify the effects of the method of fixation on peri-prosthetic tibial bone density beneath cemented and uncemented tibial components of similar design and with similar long-term survival rates. Standard radiographs taken between two months and 15 years post-operatively were digitised from a matched group of TKRs using cemented (n = 67) and uncemented (n = 67) AGC tibial prostheses. Digital radiograph densitometry was used to quantify changes in bone density over time. Age, length of follow-up, gender, body mass index and alignment each significantly influenced the long-term pattern of peri-prosthetic bone density. Similar long-term changes in density irrespective of the method of fixation correlated well with the high rate of survival of this TKR at 20 years, and suggest that cemented and uncemented fixation are both equally viable. Cite this article: Bone Joint J 2013;95-B:911–16

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The aim of this study is to provide a detailed description of cases combining bridging patch repair with artificial ligament “internal brace” reinforcement to treat irreparable massive rotator cuff tears, and report the preliminary results.

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The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?

In order to assess current opinions on the long-term outcome after primary total hip replacement, we performed a multicentre, cross-sectional survey in 22 centres from 12 European countries. Different patient characteristics were categorised into ‘decreases chances’, ‘does not affect chances’, and ‘increases chances’ of a favourable long-term outcome, by 304 orthopaedic surgeons and 314 referring practitioners. The latter were less likely to associate age older than 80 years and obesity with a favourable outcome than orthopaedic surgeons (p < 0.001 and p = 0.006, respectively) and more likely to associate age younger than 50 years with a favourable outcome (p = 0.006). Comorbidity, rheumatoid arthritis, and poor bone quality were thought to be associated with a decreased chance of a favourable outcome. We found important differences in the opinions regarding long-term outcome after total hip replacement within and between referring practitioners and orthopaedic surgeons. These are likely to affect access to and the provision of total hip replacement

Aims

A multicentre, randomized, clinician-led, pragmatic, parallel-group orthopaedic trial of two surgical procedures was set up to obtain high-quality evidence of effectiveness. However, the trial faced recruitment challenges and struggled to maintain recruitment rates over 30%, although this is not unusual for surgical trials. We conducted a qualitative study with the aim of gathering information about recruitment practices to identify barriers to patient consent and participation to an orthopaedic trial.

Objectives. The purpose of this study was to create a novel ex vivo organ culture model for evaluating the effects of static and dynamic load on cartilage. Methods. The metatarsophalangeal joints of 12 fresh cadaveric bovine feet were skinned and dissected aseptically, and cultured for up to four weeks. Dynamic movement was applied using a custom-made machine on six joints, with the others cultured under static conditions. Chondrocyte viability and matrix glycosaminoglycan (GAG) content were evaluated by the cell viability probes, 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI), and dimethylmethylene blue (DMMB) assay, respectively. Results. Chondrocyte viability in the static model decreased significantly from 89.9% (. sd. 2.5%) (Day 0) to 66.5% (. sd. 13.1%) (Day 28), 94.7% (. sd. 1.1%) to 80. 9% (. sd. 5.8%) and 80.1% (. sd. 3.0%) to 46.9% (. sd. 8.5%) in the superficial quarter, central half and deep quarter of cartilage, respectively (p < 0.001 in each zone; one-way analysis of variance). The GAG content decreased significantly from 6.01 μg/mg (. sd. 0.06) (Day 0) to 4.71 μg/mg (. sd. 0.06) (Day 28) (p < 0.001; one-way analysis of variance). However, with dynamic movement, chondrocyte viability and GAG content were maintained at the Day 0 level over the four-week period without a significant change (chondrocyte viability: 92.0% (. sd. 4.0%) (Day 0) to 89.9% (. sd. 0.2%) (Day 28), 93.1% (. sd. 1.5%) to 93.8% (. sd. 0.9%) and 85.6% (. sd. 0.8%) to 84.0% (. sd. 2.9%) in the three corresponding zones; GAG content: 6.18 μg/mg (. sd. 0.15) (Day 0) to 6.06 μg/mg (. sd. 0.09) (Day 28)). Conclusion. Dynamic joint movement maintained chondrocyte viability and cartilage GAG content. This long-term whole joint culture model could be of value in providing a more natural and controlled platform for investigating the influence of joint movement on articular cartilage, and for evaluating novel therapies for cartilage repair. Cite this article: Y-C. Lin, A. C. Hall, A. H. R. W. Simpson. A novel organ culture model of a joint for the evaluation of static and dynamic load on articular cartilage. Bone Joint Res 2018;7:205–212. DOI: 10.1302/2046-3758.73.BJR-2017-0320

Aims

Dual mobility (DM) implants have been shown to reduce the dislocation rate after total hip arthroplasty (THA), but there remain concerns about the use of cobalt chrome liners inserted into titanium shells. The aim of this study was to assess the clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) at mid-term follow-up in young, active patients receiving a modular DM THA.

Aims. Supracondylar fractures are the most frequently occurring paediatric fractures about the elbow and may be associated with a neurovascular injury. The British Orthopaedic Association Standards for Trauma 11 (BOAST 11) guidelines describe best practice for supracondylar fracture management. This study aimed to assess whether emergency departments in the United Kingdom adhere to BOAST 11 standard 1: a documented assessment, performed on presentation, must include the status of the radial pulse, digital capillary refill time, and the individual function of the radial, median (including the anterior interosseous), and ulnar nerves. . Materials and Methods. Stage 1: We conducted a multicentre, retrospective audit of adherence to BOAST 11 standard 1. Data were collected from eight hospitals in the United Kingdom. A total of 433 children with Gartland type 2 or 3 supracondylar fractures were eligible for inclusion. A centrally created data collection sheet was used to guide objective analysis of whether BOAST 11 standard 1 was adhered to. Stage 2: We created a quality improvement proforma for use in emergency departments. This was piloted in one of the hospitals used in the primary audit and was re-audited using equivalent methodology. In all, 102 patients presenting between January 2016 and July 2017 were eligible for inclusion in the re-audit. Results. Stage 1: Of 433 patient notes audited, adherence to BOAST 11 standard 1 was between 201 (46%) and 232 (54%) for the motor and sensory function of the individual nerves specified, 318 (73%) for radial pulse, and 247 (57%) for digital capillary refill time. Stage 2: Of 102 patient notes audited, adherence to BOAST 11 standard 1 improved to between 72 (71%) and 80 (78%) for motor and sensory function of the nerves, to 84 (82%) for radial pulse, and to 82 (80%) for digital capillary refill time. Of the 102 case notes reviewed in stage 2, only 44 (43%) used the quality improvement proforma; when the proforma was used, adherence improved to between 40 (91%) and 43 (98%) throughout. Conclusion. Adherence to BOAST 11 standard 1 is poor in hospitals across the country. This is concerning as neurovascular deficit may be an indication for emergent surgery, and missed neurovascular injury can cause long-term, or even permanent, functional impairment. We present a simple proforma that improves adherence to this standard, can easily be implemented into emergency departments, and may improve patient safety. Cite this article: Bone Joint J 2018;100-B:346–51