Does location of patellofemoral chondral lesion influence outcome after Oxford medial compartmental knee arthroplasty?

AIMS: Medial unicompartmental knee arthroplasty (UKA) is associated with successful outcomes in carefully selected patient cohorts. We hypothesised that severity and location of patellofemoral cartilage lesions significantly influences functional outcome after Oxford medial compartmental knee arthroplasty. PATIENTS AND METHODS: We reviewed 100 consecutive UKAs at minimum eight-year follow-up (96 to 132). A single surgeon performed all procedures. Patients were selected based on clinical and plain radiographic assessment. All patients had end-stage medial compartment osteoarthritis (OA) with sparing of the lateral compartment and intact anterior cruciate ligaments. None of the patients had end-stage patellofemoral OA, but patients with anterior knee pain or partial thickness chondral loss were not excluded. There were 57 male and 43 female patients. The mean age at surgery was 69 years (41 to 82). At surgery the joint was carefully inspected for patellofemoral chondral loss and this was documented based on severity of cartilage loss (0 to 4 Outerbridge grading) and topographic location (medial, lateral, central, and superior or inferior). Functional scores collected included Oxford Knee Score (OKS), patient satisfaction scale and University College Hospital (UCH) knee score. Intraclass correlation was used to compare chondral damage to outcomes. RESULTS: All patients documented significant improvement in pain and improved functional scores at mid-term follow-up. There were four revisions (mean 2.9 years, 2 to 4; standard deviation (sd) 0.9) in this cohort, three for tibial loosening and one for femoral loosening. There was one infection that was treated with debridement and insert exchange. The mean OKS improved from 23.2 (sd 7.1) to 39.1 (sd 6.9); p < 0.001. The cohort with central and lateral grade 3 patellofemoral OA documented lower mean satisfaction with pain (90, sd 11.8) and function (87.5, sd 10.3) on the patient satisfaction scale. On the UCH scale, patients reported significantly decreased mean overall scores (7.3, sd 1.2 vs 9, sd 2.3) as well as stair climb task (3.5, sd 0.3 vs 5, sd 0.1) when cartilage lesions were located centrally or laterally on the PFJ. Patients with medial chondral PFJ lesions behave similar to patients with no chondral lesions. CONCLUSION: Topographical location and severity of cartilage damage of the patella can significantly influence function after successful Oxford medial UKA. Surgeons should factor this in when making their operative decision, and undertake to counsel patients appropriately. Cite this article: Bone Joint J 2016;98-B(10 Suppl B):11-15

The Postoperative Morbidity Survey was validated and used to describe morbidity after major surgery.

OBJECTIVES: To describe the reliability and validity of the Postoperative Morbidity Survey (POMS). To describe the level and pattern of short-term postoperative morbidity after major elective surgery using the POMS. STUDY DESIGN AND SETTING: This was a prospective cohort study of 439 adults undergoing major elective surgery in a UK teaching hospital. The POMS, an 18-item survey that address nine domains of postoperative morbidity, was recorded on postoperative days 3, 5, 8, and 15. RESULTS: Inter-rater reliability was perfect for 11/18 items (Kappa=1.0), with Kappa=0.94 for 6/18 items. A priori hypotheses that the POMS would discriminate between patients with known measures of morbidity risk, and predict length of stay were generally supported through observation of data trends, and there was statistically significant evidence of construct validity for all but the wound and neurological domains. POMS-defined morbidity was present in 325 of 433 patients (75.1%) remaining in hospital on postoperative day 3 after surgery, 231 of 407 patients (56.8%) on day 5, 138 of 299 patients (46.2%) on day 8, and 70 of 111 patients (63.1%) on day 15. Gastrointestinal (47.4%), infectious (46.5%), pain-related (40.3%), pulmonary (39.4%), and renal problems (33.3%) were the most common forms of morbidity. CONCLUSION: The POMS is a reliable and valid survey of short-term postoperative morbidity in major elective surgery. Many patients remain in hospital without any morbidity as recorded by the POMS

Does cemented or cementless single-stage exchange arthroplasty of chronic periprosthetic hip infections provide similar infection rates to a two-stage? A systematic review

BACKGROUND: The best surgical modality for treating chronic periprosthetic hip infections remains controversial, with a lack of randomised controlled studies. The aim of this systematic review is to compare the infection recurrence rate after a single-stage versus a two-stage exchange arthroplasty, and the rate of cemented versus cementless single-stage exchange arthroplasty for chronic periprosthetic hip infections. METHODS: We searched for eligible studies published up to December 2015. Full text or abstract in English were reviewed. We included studies reporting the infection recurrence rate as the outcome of interest following single- or two-stage exchange arthroplasty, or both, with a minimum follow-up of 12 months. Two reviewers independently abstracted data and appraised quality assessment. RESULTS: After study selection, 90 observational studies were included. The majority of studies were focused on a two-stage hip exchange arthroplasty (65 %), 18 % on a single-stage exchange, and only a 17 % were comparative studies. There was no statistically significant difference between a single-stage versus a two-stage exchange in terms of recurrence of infection in controlled studies (pooled odds ratio of 1.37 [95 % CI = 0.68-2.74, I(2) = 45.5 %]). Similarly, the recurrence infection rate in cementless versus cemented single-stage hip exchanges failed to demonstrate a significant difference, due to the substantial heterogeneity among the studies. CONCLUSION: Despite the methodological limitations and the heterogeneity between single cohorts studies, if we considered only the available controlled studies no superiority was demonstrated between a single- and two-stage exchange at a minimum of 12 months follow-up. The overalapping of confidence intervals related to single-stage cementless and cemented hip exchanges, showed no superiority of either technique

Clinical and Biomechanical Assessment of the Treatment of Type B Periprosthetic Fractures of the Femur

Total hip arthroplasty is a well established treatment modality for the diseased hip. The number implanted rises annually on a global scale which is mirrored by increasing indications. After aseptic loosening and infection, periprosthetic fracture remains one of the commonest complications of this otherwise successful surgery. Management is geared towards restoring function through fixation of the fracture. The general aim of this thesis is to validate the classification of periprosthetic fractures of the femur around total hip arthroplasty, provide evidence towards the outcomes of methods of fixation of these fractures, and present supplementary biomechanical data regarding fixation and implant stress. It is hypothesised that the Vancouver classification will be a reliable and reproducible system to use, that strut grafts, cables and long-stemmed implants will improve function and outcome when used to manage these injuries, and that biomechanical models will provide evidence on why the use of the implants is successful. Study I The purpose of this study was to ensure that the Vancouver Classification of periprosthetic fractures which is most widely used classification system of periprosthetic fractures is repeatable. It was hypothesised that the system would be reliable amongst for all grades of clinician. The inter-rater agreement ranged from 0.61-0.74 and the intra-rater agreement ranged from 0.59-0.67. Validity analysis was scored at 77% (κ = 0.67). The Vancouver Classification was shown to be reliable and reproducible. Study II The purpose of this study was to evaluate the clinical and radiographic outcomes of 40 periprosthetic femoral fractures around stable hip implants treated with cortical onlay strut allografts without revision of the stem. It was hypothesised that this treatment would improve function and result in bony union. At a mean follow-up of 28 months, 98% of patients had radiological evidence of union with all but one of the surviving patients returned to their preoperative functional level within one year. Study III The purpose of this biomechanical cadaveric study was to determine the effect of allograft cortical strut length, configuration, cable number, cable tension and the use of wire or cable on the fixation of periprosthetic femoral fractures. It was hypothesised that an increasing number of struts and the use of cable would improve fracture stability. Fracture stability was found to increase with the use of two rather than one strut, and by using cables rather than wires. Study IV The purpose of this study was to evaluate the clinical and radiological outcomes of using cementless femoral stems in conjunction with cortical struts, cable plating systems, bone allograft and demineralised bone matrix in 26 patients with Vancouver B2 or B3 fractures. It was hypothesised that this treatment would improve function and lead to radiological union. It was found that all fractures were healed clinically and radiologically, and all patients were reported to be satisfied with the outcome. Study V The purpose of this biomechanical study was to determine the strain exerted by an uncemented femoral implant upon a synthetic, composite femur modelling various clinical scenarios. It was hypothesised that strain would be reduced when using a grip, strut or cables. It was found that these devices did reduce the strain exerted upon the femur and may be useful in preventing femoral stem fractures. Study VI The purpose of this study was to evaluate the clinical and radiographic outcomes of treating periprosthetic femoral fractures around unstable hip implants treated with revision to an uncoated locked Kent Hip prosthesis. It was hypothesised that this method of treatment would improve clinical and radiological outcome in the 36 patients included in the study group. Harris Hip Scores improved and fracture union was seen in all but one patient; there were three patients in whom the implant was subsequently revised. Study VII The purpose of this study was to clinically evaluate interlocking long stem femoral prostheses as either temporary functional spacers or as definitive implants in cases of infected periprosthetic femoral fractures. It was hypothesised that these devices would improve the clinical and radiological outcomes of these patients. The Cannulok uncoated stem was used in twelve cases and the Kent Hip Prosthesis in five cases. Patients were asked post-operatively they were satisfied with the outcome achieved. All patients were satisfied and in eleven cases, revision to a definitive stem was undertaken after successful control of the infection and fracture union. Conclusions The management of periprosthetic fractures is a complex issue. There are numerous ways to manage this injury and treatment must be tailored to the patient and to the specific injury sustained. The results of this work demonstrate that classifying periprosthetic fractures using the Vancouver system is valid. Furthermore cortical struts are an effective adjunct with proven biomechanical advantages in non-infected cases around stable implants, whilst long cementless stems lead to excellent outcomes in the presence of a loose implant irrespective of infection

Is single-stage revision according to a strict protocol effective in treatment of chronic knee arthroplasty infections?

The increasing number of patients experiencing periprosthetic total knee arthroplasty (TKA) infections and the cost of treating them suggest that we seek alternatives to two-stage revision. Single-stage revision is a potential alternative to the standard two-stage procedure because it involves only one surgical procedure, so if it is comparably effective, it would be associated with less patient morbidity and lower cost

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

A systematic review of the evidence for single stage and two stage revision of infected knee replacement

BACKGROUND: Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates. METHODS: A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded. RESULTS: 63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies. CONCLUSIONS: Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV