ICON 2020-International Scientific Tendinopathy Symposium Consensus: the development of a core outcome set for gluteal tendinopathy

Gluteal tendinopathy (GT) is common and can be debilitating and challenging to manage. A lack of condition specific and appropriate outcome measures compromise evidence synthesis for treatment and limits clinical guideline development. Our objective was to develop a core outcome measurement set for GT (COS-GT). Participants were patients with GT and expert health professionals (HPs). A scoping review identified measures used in GT research, which were mapped to the nine International Scientific Tendinopathy Symposium Consensus core domains, and included in two surveys of HPs. The first survey identified the feasible and true measures for each domain. The second survey refined the list which a patient focus group then considered. Meeting online, HPs reached consensus (agreement ≥70%) on the most appropriate COS-GT measures. 34 HPs and seven patients were recruited. 57 measures were mapped to the nine core domains. Six measures did not proceed past survey one. Of those that progressed, none had adequate clinimetric properties for a COS-GT. Thus, participants decided on interim measures: the global rating of change, pain at night, time to pain onset with single limb stance, pain with stair walking, pain self-efficacy and hip abduction strength. HP participants additionally recommended that pain over the last week, the European Quality of Life-5 dimensions-5 levels and the Victorian Institute of Sport Assessment-Gluteal be considered in clinical trials, as they currently provide best easures of the relevant tendinopathy domains. In conclusion this interim COS-GT should guide outcome measure selection in clinical practice and future research trials in patients with GT.

Sex-Specific Implant Fixation Can Reduce Revision Rates in Total Hip Arthroplasty: Evidence From the Swiss National Joint Registry

BACKGROUND

Patient's sex is considered a risk factor for revision following primary total hip arthroplasty (THA), but sex-specific treatment guidelines are lacking. The purpose was to assess sex-specificity of risk factors for periprosthetic femoral fractures (PFFs) and aseptic stem loosening (ASL) in a nationwide register study.

METHODS

All uncemented and hybrid THAs for hip osteoarthritis registered in the Swiss National Joint Registry were considered. 86,423 THAs were analyzed. Comparable THA subsets for both sexes were obtained through propensity score matching (1:1). A sex-specific analysis of risk factors for early PFF or ASL was performed using recursive partitioning analyses.

RESULTS

In women, PFFs were most significantly associated with uncemented THA fixation (P < .0001) and age (P < .01, threshold: 70.5 years). The ASLs were solely associated with patient age of <65 years (P = .023). In men, PFFs were associated exclusively with an American Society of Anesthesiologists (ASA) score >2 (P = .026). The ASLs were not correlated to any of the potential risk factors analyzed. A mathematical simulation indicated that avoiding uncemented THA fixation in women ≥70.5 years of age decreased the number of revisions within the observational period by 21% in this subset and by 4.9% in the entire patient population.

CONCLUSION

Uncemented THA should be avoided in women >70.5 years due to the increased risk of early PFF, while the mode of stem fixation did not influence revision risk in men. A sex-specific regimen for THA fixation has the potential to markedly reduce early THA revision rates.

ADP-ribosyltransferases, an update on function and nomenclature

ADP-ribosylation, a modification of proteins, nucleic acids, and metabolites, confers broad functions, including roles in stress responses elicited, for example, by DNA damage and viral infection and is involved in intra- and extracellular signaling, chromatin and transcriptional regulation, protein biosynthesis, and cell death. ADP-ribosylation is catalyzed by ADP-ribosyltransferases (ARTs), which transfer ADP-ribose from NAD+ onto substrates. The modification, which occurs as mono- or poly-ADP-ribosylation, is reversible due to the action of different ADP-ribosylhydrolases. Importantly, inhibitors of ARTs are approved or are being developed for clinical use. Moreover, ADP-ribosylhydrolases are being assessed as therapeutic targets, foremost as antiviral drugs and for oncological indications. Due to the development of novel reagents and major technological advances that allow the study of ADP-ribosylation in unprecedented detail, an increasing number of cellular processes and pathways are being identified that are regulated by ADP-ribosylation. In addition, characterization of biochemical and structural aspects of the ARTs and their catalytic activities have expanded our understanding of this protein family. This increased knowledge requires that a common nomenclature be used to describe the relevant enzymes. Therefore, in this viewpoint, we propose an updated and broadly supported nomenclature for mammalian ARTs that will facilitate future discussions when addressing the biochemistry and biology of ADP-ribosylation. This is combined with a brief description of the main functions of mammalian ARTs to illustrate the increasing diversity of mono- and poly-ADP-ribose mediated cellular processes.

Direct anterior approach improves in-hospital mobility following hemiarthroplasty for femoral neck fracture treatment

INTRODUCTION

In elderly patients, an established treatment for femoral neck fractures is hip hemiarthroplasty (HHA) using the anterolateral approach (ALA). Early postoperative mobilization is crucial to reduce perioperative complications. The direct anterior approach (DAA) has been reported to facilitate early recovery of ambulation and is increasingly popular in elective hip surgery but rarely used in femoral neck fractures. The aim was to compare the outcome of the DAA and the ALA in patients treated for femoral neck fracture.

MATERIALS AND METHODS

All HHAs with complete data sets were reviewed from a tertiary public healthcare institution (2013-2020). Propensity score matching was applied to compensate for possible confounders; outcome parameters were perioperative blood loss, postoperative mobility and pain. Secondary outcomes were duration of surgery, length of stay (LOS), complications, reoperation and mortality rates.

RESULTS

There were 237 patients (mean age 85.8 years) available for analysis. The DAA group mobilized earlier during hospitalization (outside patient room: 50.6 vs 38.6%, p = 0.01; walking on crutches/walker: 48.1 vs 36.1%, p < 0.01), had shorter surgeries (DAA vs ALA: 72.5 vs 89.5 min, p < 0.001) and a trend towards fewer complications (32.9% vs 44.9%, p = 0.076). Blood loss (286 vs 287 ml), LOS (10.4 vs 9.5 days), pain (cessation of opioid medication: 2.9 vs 3.3 days post-op), revision (2.5 vs 3.2%) or mortality (30-days: 7.6 vs 5.7%) did not differ between patient groups.

CONCLUSIONS

DAA for HHA led to earlier in-hospital mobility, shorter surgeries and a tendency towards fewer complications. No advantage was found regarding perioperative blood loss and pain.

Aseptic Revision of Total Hip Arthroplasty With a Single Modular Femoral Stem and a Modified Extended Trochanteric Osteotomy-Treatment Assessment With the Forgotten Joint Score-12

Background

Aseptic loosening is among the most common reasons for revision total hip arthroplasty (RTHA). Modular revision stems implanted through an extended trochanteric osteotomy (ETO) promise good results, but patient-reported outcome measures (PROMs) are rarely conveyed. This study used the Forgotten Joint Score-12 (FJS-12) to assess patient-reported outcome in patients who had undergone RTHA for aseptic stem loosening using a modified ETO approach with a tapered, fluted modular stem.

Material and methods

A single-center analysis of aseptic RTHA was performed (2007–2019). Clinical results (range of motion, walking ability, function), radiographic results (ETO healing, stem subsidence), and PROMs (FJS-12, Harris Hip Score, European Quality of Life 5D Score) were assessed. Minimum follow-up duration was 1 year. Complications including revisions were recorded.

Results

Primary outcome parameters were assessed on 72 patients (mean age 73.3 years, mean body mass index 27.6kg/m²). Additional PROMs were collected by phone interviews from 41 patients (mean follow-up 5.7 years). In 76%, leg length was restored, and a normal gait was achieved. After 1 year, the ETO was healed in 93%; subsidence occurred in 8.3% of cases. The mean FJS-12 at the final follow-up was 85.6 ± 23.6, and the respective Harris Hip Score and European Quality of Life 5D Score averaged 87 ± 17.8 and 72.9 ± 15.9. Complication and revision rates were 33.3% and 13.9%, respectively.

Conclusion

Aseptic RTHA as presented here resulted in excellent PROMs in the medium term. FJS-12 score averaged 85.6 with a mean follow-up of 5.7 years. Treatment using a modular implant and a modified ETO was associated with good clinical and radiographic outcomes. Complication and revision rates were 33.3% and 13.9%, respectively.

Mid-term outcomes following transfemoral revision of total hip arthroplasty for Vancouver B2/B3 periprosthetic fractures

INTRODUCTION

Periprosthetic femoral fractures (PFF) are often the reason for revising total hip arthroplasty (RTHA). Converting these fractures into modified extended trochanteric osteotomy (mETO) facilitates stem revision. Modular revision stems are a common choice with good results. We present mid-term outcomes in patients undergoing RTHA for Vancouver B2/B3 PFF using a tapered, fluted modular stem with an mETO approach.

MATERIALS AND METHODS

A single-center analysis of patients with RTHA for Vancouver B2/B3 PFF using a single modular implant with mETO was performed (2007 - 2019). Clinical outcome (mobility, range of motion, function), radiological outcome (fracture healing, stem subsidence) and patient reported outcome measures (FJS-12, HHS, EQ-5D) were assessed.

RESULTS

Ninety-seven patients (mean age 78.1 years, BMI 25.8 kg/m², 85.6% B2-fractures) were included; 80 patients had complete clinical and radiological follow-ups. Normal unaided gait without limping was achieved in 38/80 patients. After one year fracture / mETO healing occurred in 74/80 patients; 5.3 years after surgery, the respective FJS-12, HHS and EQ-5D (available in 34 patients) averaged 81.3 ± 30.2, 71.4 ± 18.7 and 0.8 ± 0.2. We documented 7 in-hospital deaths, 18.8% postoperative complications and 13.8% revisions with stem revisions being most commonly for subsequent PFF or subsidence.

CONCLUSION

Good clinical and radiological outcomes and rather low complication and revision rates (18.8% and 13.8%) were achieved. FJS-12 showed excellent results in patients undergoing RTHA for Vancouver B2/B3 PFF using a cementless, dual modular titanium revision stem and an mETO approach. Joint awareness was thereby similar to previously reported primary THA results at 5.3 years follow-up.

Different outcomes after proximal femoral replacement in oncologic and failed revision arthroplasty patients - a retrospective cohort study

Background

Proximal femoral replacement (PFR) is a technically demanding procedure commonly performed to restore extensive, oncological or non-oncological bone defects in a severely debilitated patient collective. Depending on different indications, a varying outcome has been reported. The aim of the study was to assess the functional outcomes and complication rates of PFR with the modular Munich-Luebeck (MML) femoral megaprosthesis (ESKA/Orthodynamics, Luebeck, Germany), and to highlight outcome differences in patients treated for failed revision total hip arthroplasty (THA) or malignant bone disease.

Methods

A retrospective review of patients treated with PFR for failed THA or malignant tumor disease between 2000 and 2012 was performed. Patient satisfaction, functional outcome (VAS, SF-12, MSTS, WOMAC, TESS), complications and failure types (Henderson’s failure classification) were assessed. A Kaplan-Meier analysis determined implant survival.

Results

Fifty-eight patients (age: 69.9 years, BMI: 26.7 kg/m², mean follow-up: 66 months) were included. The mean SF-12 (physical / mental) was 37.9 / 48.4. MSTS averaged 68% at final follow-up, while mean WOMAC and TESS scored 37.8 and 59.5. TESS and WOMAC scores demonstrated significantly worse outcomes in the revision group (RG) compared to the tumor group (TG). Overall complication rate was 43.1%, and dislocation was the most common complication (27.6%). Implant survival rates were 83% (RG) and 85% (TG; p = n.s.) at 5 years, while 10-year survival was 57% (RG) and 85% (TG, p < 0.05).

Conclusions

PFR is a salvage procedure for restoration of mechanical integrity and limb preservation after extensive bone loss. Complications rates are considerably high.

Functional outcomes and 10-year implant survival rate were worse in the RG compared to the TG. Strict indications and disease-specific patient education are essential in preoperative planning and prognosis.

Treatment of Gluteal Tendinopathy: A Systematic Review and Stage-Adjusted Treatment Recommendation

Background:

Gluteal tendinopathy is the most common lower limb tendinopathy. It presents with varying severity but may cause debilitating lateral hip pain.

Purpose:

To review the therapeutic options for different stages of gluteal tendinopathy, to highlight gaps within the existing evidence, and to provide guidelines for a stage-adjusted therapy for gluteal tendinopathy.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We screened Scopus, Embase, Web of Science, PubMed, PubMed Central, Ovid MEDLINE, CINAHL, UpToDate, and Google Scholar databases and databases for grey literature. Patient selection, diagnostic criteria, type and effect of a therapeutic intervention, details regarding aftercare, outcome assessments, complications of the treatment, follow-up, and conclusion of the authors were recorded. An assessment of study methodological quality (type of study, level of evidence) was also performed. Statistical analysis was descriptive. Data from multiple studies were combined if they were obtained from a single patient population. Weighted mean and range calculations were performed.

Results:

A total of 27 studies (6 randomized controlled trials) with 1103 patients (1106 hips) were included. The mean age was 53.7 years (range, 17-88 years), and the mean body mass index was 28.3. The ratio of female to male patients was 7:1. Radiological confirmation of the diagnosis was most commonly obtained using magnetic resonance imaging. Reported treatment methods were physical therapy/exercise; injections (corticosteroids, platelet-rich plasma, autologous tenocytes) with or without needle tenotomy/tendon fenestration; shockwave therapy; therapeutic ultrasound; and surgical procedures such as bursectomy, iliotibial band release, and endoscopic or open tendon repair (with or without tendon augmentation).

Conclusion:

There was good evidence for using platelet-rich plasma in grades 1 and 2 tendinopathy. Shockwave therapy, exercise, and corticosteroids showed good outcomes, but the effect of corticosteroids was short term. Bursectomy with or without iliotibial band release was a valuable treatment option in grades 1 and 2 tendinopathy. Insufficient evidence was available to provide guidelines for the treatment of partial-thickness tears. There was low-level evidence to support surgical repair for grades 3 (partial-thickness tears) and 4 (full-thickness tears) tendinopathy. Fatty degeneration, atrophy, and retraction can impair surgical repair, while their effect on patient outcomes remains controversial.

Higher body mass index is associated with larger postoperative improvement in patient-reported outcomes following total knee arthroplasty

BACKGROUND

Total knee arthroplasty is known to successfully alleviate pain and improve function in endstage knee osteoarthritis. However, there is some controversy with regard to the influence of obesity on clinical benefits after TKA. The aim of this study was to investigate the impact of body mass index (BMI) on improvement in pain, function and general health status following total knee arthroplasty (TKA).

METHODS

A single-centre retrospective analysis of primary TKAs performed between 2006 and 2016 was performed. Data were collected preoperatively and 12-month postoperatively using WOMAC score and EQ-5D. Longitudinal score change was compared across the BMI categories identified by the World Health Organization.

RESULTS

Data from 1565 patients [mean age 69.1, 62.2% women] were accessed. Weight distribution was: 21.2% BMI < 25.0 kg/m2, 36.9% BMI 25.0-29.9 kg/m2, 27.0% BMI 30.0-34.9 kg/m2, 10.2% BMI 35.0-39.9 kg/m2, and 4.6% BMI ≥ 40.0 kg/m2. All outcome measures improved between preoperative and 12-month follow-up (p < 0.001). In pairwise comparisons against normal weight patients, patients with class I-II obesity showed larger improvement on the WOMAC function and total score. For WOMAC pain improvements were larger for all three obesity classes.

CONCLUSIONS

Post-operative improvement in joint-specific outcomes was larger in obese patients compared to normal weight patients. These findings suggest that obese patients may have the greatest benefits from TKA with regard to function and pain relief one year post-op. Well balanced treatment decisions should fully account for both: Higher benefits in terms of pain relief and function as well as increased potential risks and complications. Trial registration This trial has been registered with the ethics committee of Eastern Switzerland (EKOS; Project-ID: EKOS 2020-00,879).

Radiostereometric Analysis Allows Assessment of the Stability and Inducible Displacement of Pelvic Ring Disruptions during Healing: A Case Series

There is currently no accurate data on fracture displacement during the rehabilitation of pelvic ring injuries. This study investigated the use of radiostereometric analysis (RSA) in assessing the stability of C1 pelvic ring injuries stabilised with a posterior plate and an anterior external fixator. Six patients, instructed to weight-bear as tolerated after surgery, were reviewed at 2, 4, 6, 12, 26, 52 and 104 weeks. The external fixators were removed at 6 weeks. Outcomes, including the Iowa Pelvic Score (IPS), and complications were recorded. Fracture stability was assessed using measurements on plain radiographs and RSA. All patients progressed to full weight-bearing without support within 6 weeks. At 104 weeks, the IPS was excellent in four patients, good in one patient and fair in one patient. Plain radiographs showed that all fractures were well reduced, and no loss of reduction occurred over time. By contrast, RSA measurements identified displacement in all cases. The maximum three-dimensional (3D) displacement at any time point in each patient ranged from 2 to 10 mm. Two patients with the largest displacement over time had the lowest IPS. RSA also demonstrated displacements above the currently defined normal threshold through the ‘un-injured’ sacroiliac joint in the same two patients, suggesting a subtle C2 injury, missed at initial assessment. This study demonstrates the limitations of plain radiographs in assessing pelvic fracture stability and displacement during healing, and the potential of RSA to monitor more accurately the effects of stabilisation and weight-bearing on fracture stability.

The impact of a hands-on arthrocentesis workshop in undergraduate medical education

BACKGROUND

To evaluate the impact of a training programme for arthrocentesis on procedural skills enhancement and self-confidence in medical students.

METHODS

Participants were provided a structured workshop on injection models. A self-confidence questionnaire and medical knowledge assessment were performed. Retention of knowledge and skills were assessed at a later time point during a formal OSCE examination and compared to participants who had not attended a lecture and clinical attachments only. P-values, 95% confidence intervals about the mean, standard error of the mean, and standard deviations of the differences were calculated.

RESULTS

All participants gained self-confidence, and improvement of their skills was significant. The mean self-confidence with performing an arthrocentesis procedure increased from 1.3 pre- to 5.9 points post-workshop (10-point Likert scale). The knee was the joint students felt most confident with (1.3 to 6.5 points). Knowledge on the selection of corticosteroid preparations (1.2 to 5.8 points) gained substantially, as well as confidence in providing post-injection advice (1.9 to 6.6 points). Upon the OSCE examination, attendance to the workshop resulted in a significant higher total score (16.2 vs 14.8 points, p < 0.05).

CONCLUSIONS

A workshop for arthrocentesis procedures, in conjunction with other learning activities, is well suited to increasing skills and self-confidence in fourth year medical students and allows for developing important baseline knowledge and practicing invasive techniques without risk to a patient.

TRIAL REGISTRATION

This trial has been approved by the human research ethics committee of the University of Adelaide (Ethics approval No H-2019-134).

The Forgotten Joint Score-12 as a valuable patient-reported outcome measure for patients after first-time patellar dislocation

BACKGROUND

The aim of this study is to assess joint awareness after first-time patellar dislocation using the Forgotten Joint Score-12 (FJS-12) and to compare performance of this measurement tool to acknowledged patient-reported outcome scores.

METHODS

A retrospective analysis of patients with confirmed first-time patellar dislocation was performed. Patients were assessed with the FJS-12, the Kujala and the WOMAC scores. Reference values for the FJS-12 were obtained from a matched healthy control group with no history of previous knee joint pathology. We calculated Cronbach's alpha, assessed the ceiling effect for all scores, and calculated the Spearman correlation coefficient between them RESULTS: Fifty-six patients (mean follow-up 8.2 years, range 1.6-14.1) with a mean age of 26.4 years were analysed. Compared with the age- and gender-matched control group, the patellar dislocation group showed significantly lower (worse) mean FJS-12 scores (88 vs. 71, P < 0.001). Inter-score correlation between the FJS-12 and the Kujala was high (r = 0.74) and significant (P < 0.001), as well as between FJS-12 and WOMAC (r = 0.81, P < 0.001). Cronbach's alpha of the FJS-12 was 0.92 (95% confidence interval 0.90-0.94). The FJS-12 showed less ceiling effect (16%) compared with the Kujala score (23%) and the WOMAC score (32%).

CONCLUSIONS

The concept of joint awareness has been successfully applied to a patient population after patellar dislocation. The FJS-12 showed less ceiling effect compared with the Kujala and the WOMAC scores, suggesting the score was able to capture subtle knee problems in patients after patellar dislocation.

Proximal Femoral Nail Unlocked versus Locked (ProFNUL): a protocol for a multicentre, parallel-armed randomised controlled trial for the effect of femoral nail mode of lag screw locking and screw configuration in the treatment of intertrochanteric femur fractures

INTRODUCTION

Intertrochanteric fractures are common fragility injuries in the elderly. Surgical fixation using intramedullary devices are one of the widely used management options. To date, evidence demonstrating the effects of lag screw configuration and the mode of lag screw locking in these devices is lacking. The purpose of this study is to investigate whether the lag screw configuration (single vs integrated dual interlocking screw) and the mode of lag screw locking (static vs dynamic) of a femoral nail device result in differences in clinical and functional outcomes.

METHODS AND ANALYSIS

A multicentre, pragmatic, single-blinded randomised controlled trial (RCT) with a three-arm parallel group design is proposed. Nine-hundred patients with intertrochanteric fractures (A1 and A2 AO/OTA) will be randomised to fracture treatment using a Gamma3 nail (Stryker; proximally dynamic) or a Trigen Intertan nail (Smith & Nephew) in a dynamic or static lag screw configuration. The primary outcome measure consists of radiological evidence of construct failure within 6 months following surgery, with failure being defined as breakage of the femoral nail or distal locking screw, a change in tip-apex distance of more than 10 mm or lag screw cut-out through the femoral head. Secondary outcomes include surgical data (operation time, fluoroscopy time), complications (surgical site infection, reoperation, patient death), return to mobility and home circumstances, functional independence, function and pain. Patients who are able to walk independently with or without a mobility aid and are able to answer simple questions and follow instructions will be asked to participate in three dimensional gait analysis at 6 weeks and 6 months to assess hip biomechanics from this cohort. Additional secondary measures of gait speed, hip range of motion, joint contact and muscle forces and gross activity monitoring patterns will be obtained in this subgroup.

ETHICS AND DISSEMINATION

The Central Adelaide Local Health Network Human Research Ethics Committee has approved the protocol for this RCT (HREC/17/RAH/433). The results will be disseminated via peer-reviewed publications and presentations at relevant conferences.

TRIAL REGISTRATION NUMBER

ACTRN12618001431213.

Decrease surgery time by using an alternative lateral parapatellar approach for tibia shaft fracture nailing

INTRODUCTION

Medial parapatellar or transpatellar ligament approaches are commonly used for nail osteosynthesis in tibia shaft fractures. The lower leg is normally in a hanging position to allow guide wire insertion and reaming of the tibia. However, this position complicates fracture reduction and retention, as well as image intensification throughout the procedure. A lateral parapatellar approach with the lower leg in a semi-extended, horizontal position has been previously described for proximal tibial fracture fixation. The purpose of the presented study was to share the lateral parapatellar approach technique used in our institution and to analyse its feasibility for tibia shaft fracture fixation when compared to a medial parapatellar and transpatellar incision technique.

MATERIALS AND METHODS

All patients with tibial shaft fractures treated at our institution between 2009 and 2012 by intramedullary nailing through either a transpatellar, a medial parapatellar or a lateral parapatellar approach were reviewed. Demographics, injury pattern and the operative procedure, especially operation and fluoroscopy time, were analysed.

RESULTS

73 patients were enrolled into the study. Twenty-six patients were treated by use of a lateral parapatellar approach, whilst a transpatellar or a medial parapatellar approach was chosen in 29 and 18 cases, respectively. Patients' characteristics were similar regarding gender and body mass index. When compared to the transpatellar (126 ± 30 min) or the medial parapatellar approach (105 ± 29 min), surgical time was significantly shorter in the lateral parapatellar approach group (96 ± 29 min). Likewise, shorter image intensifier time was documented when a lateral parapatellar approach was chosen (211 ± 189 s) compared to the transpatellar (347 ± 204 s) or the medial parapatellar approach (241 ± 222 s).

CONCLUSION

The extra-articular semi-extended tibial nailing technique using a lateral parapatellar approach was associated with a significant decrease in time of surgery, while fluoroscopy time was shorter but not significantly different between the three groups.

Femoral Bone Restoration Patterns in Revision Total Hip Arthroplasty Using Distally Fixed Modular Tapered Titanium Stems and an Extended Trochanteric Osteotomy Approach

BACKGROUND

Mechanical failure of modular revision stems is a serious complication in revision total hip arthroplasty. The lack of adequate osseous support to the proximal component, especially in cases of an extended trochanteric osteotomy approach, is considered a risk factor for stem failure. In this study, we analyze proximal bone regeneration patterns in patients undergoing revision total hip arthroplasty for aseptic stem loosening through an extended trochanteric osteotomy approach using an uncemented dual modular stem.

METHODS

Fifty-four patients treated for aseptic stem loosening were radiologically reviewed. The femur was divided according to the Gruen zones. Preoperative bone loss, formation of new cancellous bone, and presence of direct osseous contact to the stem were noted right away for each Gruen zone. The presence of osseous support at the modular junction and the proximal component were examined.

RESULTS

All patients showed restoration of proximal bone mass at final follow up. New bone formation was first seen in more distally located Gruen zones. Cases with longer proximal components had a trend toward earlier osseous support at the modular junction. Overall, 75% of patients showed osseous support at the modular junction 2 years after surgery.

CONCLUSION

Restoration of proximal bone occurs in a distal to proximal direction. Shorter proximal components require more time until osseous support to the modular junction is achieved, which may result in a higher risk of mechanical failure. Based on this study, bony support at the modular junction should not be expected in 25% of cases 2 years after surgery.

Modified Extended Trochanteric Osteotomy for the Treatment of Vancouver B2/B3 Periprosthetic Fractures of the Femur

BACKGROUND

Femoral component revision is the treatment of choice for Vancouver type B2/B3 periprosthetic femur fractures (PFFs). The purpose of this study was to report the clinical outcome of revision total hip arthroplasty with the use of a modified extended trochanteric osteotomy (ETO) in PFF treatment.

METHODS

A total of 43 cases between 2000 and 2014 were analyzed. Clinical and radiographic evaluation was performed with a mean follow-up of 40 months. Patient survival after revision surgery, complications, radiographic outcomes, and quality of life and hip function were assessed.

RESULTS

Merle d'Aubignè and Postel score averaged 15, and mean postoperative Harris hip score was 70. Radiographic evaluation revealed that the ETO and fractures healed in all but 1 patient within 9 months. Component stability and apparent osseointegration were not coincident with healing of the osteotomy and fracture sites proximal to the inserted stem. Six patients (15%) developed postoperative complications, which included the following: 1 nonunion with progressive subsidence, 2 hip dislocations, 2 deep infections, and 1 breakage of the modular junction of the revision stem.

CONCLUSION

The modified ETO with a lateral approach to the hip for the treatment of PFF is compatible with fracture healing, a low dislocation rate, and good clinical results. However, component stability and apparent osseointegration are coincident with fracture healing only in the distal aspect of the inserted stem. Absence of proximal osseointegration might lead to poor osseous support resulting in inadequate fatigue strength at the junction of the dual modular revision stem.

[Epileptic seizure-induced vertebral body fractures]

In the literature epilepsy is described as the most common cause of generalized seizures. Vertebral body fractures are a rare complication of epileptic convulsions, occurring with an incidence of 3%. We present the case of a 37-year-old healthy patient, who sustained contiguous fractures of the thoracic and lumbar spine during the first manifestation of epilepsy with primary localized and then secondary generalized epileptic seizures. A complication-free outcome was achieved with a combination of conservative and operative therapies.

Stress-induced PARP activation mediates recruitment of Drosophila Mi-2 to promote heat shock gene expression

Eukaryotic cells respond to genomic and environmental stresses, such as DNA damage and heat shock (HS), with the synthesis of poly-[ADP-ribose] (PAR) at specific chromatin regions, such as DNA breaks or HS genes, by PAR polymerases (PARP). Little is known about the role of this modification during cellular stress responses. We show here that the nucleosome remodeler dMi-2 is recruited to active HS genes in a PARP–dependent manner. dMi-2 binds PAR suggesting that this physical interaction is important for recruitment. Indeed, a dMi-2 mutant unable to bind PAR does not localise to active HS loci in vivo. We have identified several dMi-2 regions which bind PAR independently in vitro, including the chromodomains and regions near the N-terminus containing motifs rich in K and R residues. Moreover, upon HS gene activation, dMi-2 associates with nascent HS gene transcripts, and its catalytic activity is required for efficient transcription and co-transcriptional RNA processing. RNA and PAR compete for dMi-2 binding in vitro, suggesting a two step process for dMi-2 association with active HS genes: initial recruitment to the locus via PAR interaction, followed by binding to nascent RNA transcripts. We suggest that stress-induced chromatin PARylation serves to rapidly attract factors that are required for an efficient and timely transcriptional response.

Cells respond to elevated temperatures with the rapid activation of heat shock genes to ensure cellular survival. Heat shock gene activation involves the synthesis of poly-[ADP-ribose] (PAR) at heat shock loci, the opening of chromatin structure, and the coordinated recruitment of transcription factors and chromatin regulators RNA polymerase II and components of the RNA processing machinery. The molecular roles of PAR and and ATP-dependent chromatin remodelers in heat shock gene activation are not clear. We show here that the chromatin remodeler dMi-2 is recruited to Drosophila heat shock genes in a PAR–dependent manner. We provide evidence that recruitment involves direct binding of dMi-2 to PAR polymers and identify novel PAR sensing regions in the dMi-2 protein, including the chromodomains and a series of motifs rich in K and R residues. Upon HS gene activation, dMi-2 associates with nascent transcripts. In addition, we find that dMi-2 and its catalytic activity are important for heat shock gene activation and co-transcriptional RNA processing efficiency. Our study uncovers a novel role of PAR during heat shock gene activation and establishes an unanticipated link between chromatin remodeler activity and RNA processing.

A mitotic beacon reveals its nucleosome anchor

Mitosis, nuclear envelope formation, and nucleocytoplasmic transport require chromosomes to identify themselves by enriching Ran-GTP around the chromatin fiber. In a recent Nature report, Makde et al. (2010) describe the structure of the Ran activator RCC1 anchored onto nucleosomes.

SirT1 in muscle physiology and disease: lessons from mouse models

Sirtuin 1 (SirT1) is the largest of the seven members of the sirtuin family of class III nicotinamide adenine dinucleotide (NAD(+))-dependent protein deacetylases, whose activation is beneficial for metabolic, neurodegenerative, inflammatory and neoplastic diseases, and augments life span in model organisms (Finkel et al., 2009; Lavu et al., 2008). In vitro studies show that SirT1 protects genome integrity and is involved in circadian physiological rhythms (Asher et al., 2008; Nakahata et al., 2008; Oberdoerffer et al., 2008). In the last few years, a fundamental role for SirT1 in the metabolism and differentiation of skeletal muscle cells has been uncovered (Fulco et al., 2003), and the use of specific transgenic or knockout SirT1 mouse models implicates it in the protection of heart muscle from oxidative and hypertrophic stresses (Alcendor et al., 2007). In this Perspective, we review the recent exciting findings that have established a key role for the 'longevity' protein SirT1 in skeletal and heart muscle physiology and disease. Furthermore, given the multiple biological functions of SirT1, we discuss the unique opportunities that SirT1 mouse models can offer to improve our integrated understanding of the metabolism, as well as the regeneration and aging-associated changes in the circadian function, of skeletal and heart muscle.

N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex

Variant histone H2AZ-containing nucleosomes are involved in the regulation of gene expression. In Saccharomyces cerevisiae, chromatin deposition of histone H2AZ is mediated by the fourteen-subunit SWR1 complex, which catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2AZ. Previous work defined the role of seven SWR1 subunits (Swr1 ATPase, Swc2, Swc3, Arp6, Swc5, Yaf9, and Swc6) in maintaining complex integrity and H2AZ histone replacement activity. Here we examined the function of three additional SWR1 subunits, bromodomain containing Bdf1, actin-related protein Arp4 and Swc7, by analyzing affinity-purified mutant SWR1 complexes. We observed that depletion of Arp4 (arp4-td) substantially impaired the association of Bdf1, Yaf9, and Swc4. In contrast, loss of either Bdf1 or Swc7 had minimal effects on overall complex integrity. Furthermore, the basic H2AZ histone replacement activity of SWR1 in vitro required Arp4, but not Bdf1 or Swc7. Thus, three out of fourteen SWR1 subunits, Bdf1, Swc7, and previously noted Swc3, appear to have roles auxiliary to the basic histone replacement activity. The N-terminal region of the Swr1 ATPase subunit is necessary and sufficient to direct association of Bdf1 and Swc7, as well as Arp4, Act1, Yaf9 and Swc4. This same region contains an additional H2AZ-H2B specific binding site, distinct from the previously identified Swc2 subunit. These findings suggest that one SWR1 enzyme might be capable of binding two H2AZ-H2B dimers, and provide further insight on the hierarchy and interdependency of molecular interactions within the SWR1 complex.

High-density lipoprotein cholesterol, C-reactive protein, and prevalence and severity of coronary artery disease in 5641 consecutive patients undergoing coronary angiography

BACKGROUND

Although high-density lipoprotein cholesterol (HDL-C) and C-reactive protein (CRP) are well-established predictors for future cardiovascular events, little information is available regarding their correlation with the prevalence and severity of angiographically evaluated coronary artery disease (CAD).

MATERIAL AND METHODS

Five thousand six hundred forty-one consecutive patients undergoing coronary angiography for the evaluation of CAD were analysed. Cardiovascular risk factors were assessed by routine blood chemistry and questionnaire. CAD severity was graded by visual estimation of lumen diameter stenosis with significant stenoses defined as lumen diameter reduction of >or= 70%. Coronary angiograms were graded as one-, two- or three-vessel disease, as nonsignificant CAD (lumen irregularities < 70%) or non-CAD.

RESULTS

HDL-C (60.3 +/- 18.5 vs. 51.9 +/- 15.3 mg dL(-1); P < 0.001) was higher and CRP was lower (0.65 +/- 1.68 vs. 1.02 +/- 2.38 mg dL(-1); P < 0.001) in non-CAD (n = 1517) compared to overall CAD patients (n = 4124). CAD patients were older (65.2 +/- 10.5 years vs. 59.9 +/- 11.4 years), more often diabetics (19.2% vs. 10.6%) and hypertensives (79.2% vs. 66.0%) and included more smokers (18.8% vs. 16.5%) (all P < 0.005). Low-density lipoprotein cholesterol (124.5 +/- 38.3 vs. 126.0 +/- 36.3 mg dL(-1); P = NS) was similar in overall CAD and non-CAD patients with more statin users (43.4% vs. 27.9%; P < 0.001) among CAD patients. Comparing non-CAD with different CAD severities using analysis of variance, results did not change substantially. In a multivariate analysis, HDL-C and CRP remained independently associated with the prevalence of CAD. In addition, HDL-C is also a potent predictor for the severity of CAD.

CONCLUSIONS

In this large consecutive patient cohort, HDL-C and CRP are independently associated with the prevalence of CAD. In this analysis, HDL-C is an even stronger predictor for CAD than some other major classical risk factors.

Agonist potency at the cloned human beta-3 adrenoceptor depends on receptor expression level and nature of assay

The cloned human beta-3 adrenoceptor was expressed in Chinese hamster ovary cells at three different levels (130, 400 and 3000 fmol/mg). The potency and intrinsic activity of a range of agonists in functional assays with these cell lines rose as a function of increasing receptor density. Operational analysis of concentration-response data allowed calculation of functional affinity and efficacy of agonists at the human beta-3 adrenoceptor. The data highlighted the low efficacy of BRL 37344 ¿(RR,SS)-(+/-)-4-[(2-(2-(3-chlorophenyl)-2-hydroxyethyl)amino)-propyl] phenoxyacetate¿ for the human beta-3 adrenoceptor, which may explain its lower potency at the human receptor despite its higher affinity relative to isoprenaline. The potency of catecholamines at the human beta-3 adrenoceptor was found to be 1 to 2 orders of magnitude higher when determined in an intact cell cAMP accumulation assay compared with a membrane-based adenylyl cyclase activation assay. The reason for this enhanced sensitivity is not clear, but the result is that the potency of the natural agonist noradrenaline in the intact cell is considerably higher than predicted either from its ligand binding affinity, or from its potency in membrane-based assays. Much smaller enhancements in sensitivity were observed for compounds of the aryloxypropanolamine class such as CGP 12177 [(+/-)-4-(3-t-butylamino-2-hydroxypropoxy)benzimidazol-2-one], with the result that the rank order of potency of such agonists at the beta-3 adrenoceptor was altered. In particular, CGP 12177 exhibited high relative potency in the cyclase assay, but low relative potency in intact cell assays. These findings highlight the importance of selecting appropriate expression levels and appropriate assay methodology when cloned receptors are used to characterize agonists.