Aim

The aim of this study was to investigate the clinical relevance of an isolated positive sonication fluid culture (SFC) in patients who underwent revision surgery of a prosthetic joint. We hypothesized that cases with a positive SFC have a higher rate of infection and prosthesis failure during follow-up compared to controls with a negative SFC.

Aim

Patients with late acute periprosthetic joint infections (PJI) and treated with surgical debridement have a high failure rate. Previous studies have shown that rheumatoid arthritis (RA) is an independent risk factor for treatment failure. We conducted a case-control study to identify predictors for failure in late acute PJI treatment in RA patients. We hypothesize that patients with RA have a higher failure rate compared to controls due to the use of immunosuppressive drugs.

Aim

Late acute prosthetic joint infections (PJI) treated with surgical debridement and implant retention (DAIR) have a high failure rate. The aim of our study was to evaluate treatment outcome in late acute PJIs treated with DAIR versus implant removal.

Aim

Debridement, antibiotics and implant retention (DAIR) is the recommended treatment for all acute prosthetic joint infections (PJI). However, the efficacy of DAIR and identification of risk factors for failure in patients with late acute PJI, is not well described.

Electromechanical coupling (piezoelectricity) is present in all living beings and provides basis for sense, thoughts and mechanisms of tissue regeneration. Herein, we ventured to assess the influence of MMC in mesenchymal stem cell culture. In this study, we fabricated piezoelectric regenerative scaffolds to assess the role of electromechamical stimulation on tendon regeneration. Tendon cells were selectively stimulated in vitro by mechanical or electromechanical cues using non-piezoelectric or piezoelectric scaffolds and optimal mechanical loading (4% deformation at 0.5 Hz). This was followed up with an in vivo study to assess tendon regeneration in a rat Achilles tendon injury model. P(VDF-TrFE), scaffolds were observed to mimic the fibrous structure of tendon tissue (figure 1) and were capable of producing electrical charges up to 17 pC/N when mechanically loaded (figure 1. Genes associated with tendon specific markers (Col.I/Col III, Scx and Mkx) and mechanosensitive ion channels such as PIEZO1, TRAAK and TRPV1 were significantly upregulated (figure 2). The upregulated genes were validated with individual real time Q-PCR and bioinformatics revealed a possible regulated function. Those results were further validated in vivo. Protein expression of repaired tendons showed a correlation between increase in expression of tendon related proteins SCX, TNMD, Decorin and expression of ion channels KCNK2, TRAAK and TRPV1. Collectively, these data clearly illustrate that scaffolds made of PVDF-TrFE can produce electrical charges when mechanically loaded. Moreover, gene and protein analyses showed a positive regulation of tendon specific markers through activation mechanosensitive voltage-gated genes.

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Ceramic on ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry.

We analysed data on 111,681 primary CoC THA's and 182 linked revisions for bearing fracture recorded in the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man (NJR). We used implant codes to identify ceramic bearing composition and generated Kaplan-Meier estimates for implant survivorship. Logistic regression analyses were performed for implant size and patient specific variables to determine any associated risks for revision.

99.8% of bearings were CeramTec Biolox® products. Revisions for fracture were linked to 7 of 79,442 (0.009%) Biolox® Delta heads, 38 of 31,982 (0.119%) Biolox® Forte heads, 101 of 80,170 (0.126%) Biolox® Delta liners and 35 of 31,258 (0.112%) Biolox® Forte liners. Regression analysis of implant size revealed smaller heads had significantly higher odds of fracture (χ2=68.0, p<0.0001). The highest fracture risk were observed in the 28mm Biolox® Forte subgroup (0.382%). There were no fractures in the 40mm head group for either ceramic type. Liner thickness was not predictive of fracture (p=0.67). BMI was independently associated with revision for both head fractures (OR 1.09 per unit increase, p=0.031) and liner fractures (OR 1.06 per unit increase, p=0.006).

We report the largest registry study of CoC bearing fractures to date. Modern CoC bearing fractures are rare events. Fourth generation ceramic heads are around 10 times less likely to fracture than third generation heads, but liner fracture risk remains similar between these generations.

We sought to evaluate the impact of a dedicated weekly ortho-plastics operating list on our ability to provide definitive soft tissue cover of open lower limb fractures within 72 hours.

We reviewed all open lower limb fractures at our centre before and after the introduction of an ortho-plastics list to determine whether definitive soft tissue coverage was achieved within 72 hours.

There were 23 open lower limb fractures at our centre in 2012 before the introduction of the ortho-plastics operating list of which only 7 (30%) had definitive soft tissue coverage within 72 hours. We hypothesised that the main reason for this was not patient or injury related factors but rather the logistical difficulties of coordinating theatre time on a routine trauma list with senior orthopaedic and plastic surgeon availability. To test this hypothesis we re-audited our time to soft tissue cover six months after the introduction of the ortho-plastics list and 70% of cases achieved coverage within 72 hours.

Achieving definitive soft tissue coverage of open lower limb fractures within 72 hours of injury is a challenge. A dedicated weekly ortho-plastics operating list significantly improves our ability to deliver this service.

Urinary catheterization in the postoperative period is known to increase the risk of deep joint infection following arthroplasty. A number of studies have attempted to elucidate the individual patient factors and surgical procedural factors which predispose patients to postoperative urinary retention.

We conducted a retrospective observational study of three hundred patients to specifically determine the effect of the anaesthetic technique on the incidence of urinary retention following elective lower limb arthroplasty. One hundred consecutive patients were surveyed in each of three groups differing by the type of the anaesthetic technique and the drug administered; 1) general anaesthesia with femoral nerve block, 2) spinal anaesthesia with intrathecal fentanyl, and 3) spinal anaesthesia with intrathecal morphine.

The incidence of urinary retention requiring catheterisation in male patients receiving intrathecal morphine was 58% compared with 10% and 6% for those who had general anaesthesia with femoral nerve block and intrathecal fentanyl, respectively. This difference was statistically significant (p<0.01). The incidence of urinary retention in females across all groups was =2%. The average residual volume of urine following catheterisation was 750ml (460-1500ml).

Our findings show that the use of intrathecal morphine greatly increases the risk of postoperative urinary retention in male patients, whereas no significant increase was found amongst female patients. This risk should be carefully considered when choosing the type of intraoperative anaesthetic/analgesic combination employed in male patients and be rationalised against the intended benefits to the patient.

Purpose: To determine the incidence of anterior femoroacetabular impingement (AFAI) as a cause of idiopathic coxarthrosis in young adults.

Materials and methods: We carried out a retrospective study of 196 patients with total hip replacement (THR), selecting patients under 55 (51 cases, 26.02%). We recorded epidemiological, clinical and radiological data prior to the implantation of the THR. In all cases we used cementless stems and cups. The statistical analysis was done with SPSS software v10.0.

Results: The mean age was 50.7 (29–55). There was a predominance of men (31 cases, 61%) over women (20 cases, 39%). The mean BMI was 30.1 kg/m2 (20–42). The mean time with pain before hip arthroplasty was 8 years (2–20 years). Among the possible causes of the origin of coxarthrosis we found sequelae of acetabular fractures, hip growth dysplasias, rheumatoid arthritis, sequelae of Perthes disease and AFAI. 70.6% presented a “hump” in the head-neck junction on the axial projection, which appeared at the onset of symptoms; 10% presented frank deformity of the femoral head and 8% had protrusion of the head toward the acetabulum. The patients with AFAI presented less mean flexion (78.5°) and internal rotation (2.9°) (p< 0.05), and the predominant type of pain was inguinal irradiating to the thigh or greater trochanter (p< 0.05). The mean time from onset of symptoms to implantation of THR was less in this group (7.4 years) as compared to the rest (10.4 years) (p< 0.05).

Discussion: Murray (Br. J. Radiol 38:810–24, 1965) and Harris (CORR 213:20.23, 1986) had already mentioned AFAI as a predisposing factor in the degeneration of the coxofemoral joint. In recent years its importance has increased as the resection of the femoral hump in the initial degenerative stages has became more widespread (Tönnis 0 and I). This osteoplasty can be performed by hip arthroscopy (small humps), with dislocation of the femoral head (as described by R. Ganz) or by a very small anterior approach without dislocation of the femoral head as proposed by Ribas-Vilarubias (2004). Leunig (2005) speaks of an AFAI incidence of 15% in the general population and Tanzer (CORR 429:170-77, 2004) discovered “humps” in the femoral head-neck junction in 68–100% of patients with THR. Our study gives similar results, placing the incidence at 70.6% in patients under the age of 55 who have had a THR.

Conclusions: We think the incidence of femoroacetabular impingement is high and that this syndrome plays an important role in the onset of degeneration of the coxofemoral joint in young adults. These findings suggest the advisability of early surgery to attempt to delay the rapid progression toward primary arthroplasty at an early age.

Introduction. Tantalum is a pure metallic element and is attractive for use in orthopaedic implants because it is one of the most biocompatible metals available for implant fabrication. The potential advantages for the use of porous tantalum in total hip arthroplasty include: 1) excellent bone and tissue ingrowth observed histologically; 2) direct polyethylene intrusion into the metal substrate. This allows the elimination of any potential backside wear in the monoblock cup; 3) The two-piece design consist of a tantalum shell with screw holes for fixation into the dome of the ilium and posterior column. A polyethylene liner is cemented into the tantalum shell to eliminates backside motion. In addition, acetabular augments of porous tantalum have been developed for use in restoration of major bone deficiencies.

Prospective study on a case serie of 113 THA’s performed by two surgeons in a single institution.

Material & Methods. From 2000 to December 2003, 113 hips have undergone arthroplasty using porous tantalum implants consisting of 54 primary hip arthroplasties and 59 revision THA’s. The patients where evaluated clinical and radiographically every 3 month during the first year, and after yearly. Mean patient age was 64,2 years, (range 44–87); with 59% males and 41% females.

Results. No patients died or lost to follow-up. No further surgeries of the involved hip. No radiographic signs of loosening of the acetabular component according to the criteria of Hodgkinson et al. No problems specifically from the use of acetabular augments or extra screws has been noted. Of the revision series, a total of 16 cases have received acetabular augments.

Complications included 1 superficial infection, 2 dislocations. No vasculo-nervous complication; and in 2 cases technical difficulties to achieve good fixation due to ethiology of the THA (desarthrodesis).

The average Harris hip score improved from 48 to 89 following primary surgery.

Discussion and Conclusions Tantalum acetabular components for primary and revision hip surgery have performed well for up to 3 years, and have excellent stability.

The two-piece acetabular shell and augments permits the reconstruction of every acetabular bone defect.