Comparison of the 10-year outcomes of cemented and cementless unicompartmental knee replacements: data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

Background and purpose — Unicompartmental knee replacement (UKR) offers advantages over total replacement but has higher revision rates, particularly for aseptic loosening. The cementless Oxford UKR was introduced to address this. We undertook a registry-based matched comparison of cementless and cemented UKRs. Patients and methods — From 40,552 Oxford UKRs identified by the National Joint Registry for England, Wales, Northern Ireland and Isle of Man (NJR) we propensity score matched, based on patient, surgical, and implant factors, 7,407 cemented and 7,407 cementless UKRs (total = 14,814). Results — The 10-year cumulative implant survival rates for cementless and cemented UKRs was 93% (95% CI 90–96) and 90% (CI 88–92) respectively, with this difference being significant (HR 0.76; p = 0.002). The risk of revision for aseptic loosening was less than half (p < 0.001) in the cementless (0.42%) compared with the cemented group (1.00%), and the risk of revision also decreased for unexplained pain (to 0.46% from 0.74%; p = 0.03) and lysis (to 0.04% from 0.15%; p = 0.03). However, the risk of revision for periprosthetic fracture increased significantly (p = 0.01) in the cementless (0.26%) compared with the cemented group (0.09%). 10-year patient survival rates were similar (HR 1.2; p = 0.1). Interpretation — The cementless UKR has improved 10-year implant survival compared with the cemented UKR, independent of patient, implant, and surgical factors. This improved survival in the cementless group was primarily the result of lower revision rate for aseptic loosening, unexplained pain, and lysis, suggesting the fixation of the cementless was superior. However, there was a small increased risk of revision for periprosthetic fracture with the cementless implant

The effect of smoking on outcomes following primary total hip and knee arthroplasty: a population-based cohort study of 117,024 patients

Background and purpose — Smoking is a modifiable risk factor that may adversely affect postoperative outcomes. Healthcare providers are increasingly denying smokers access to total hip and knee arthroplasty (THA and TKA) until they stop smoking. Evidence supporting this is unclear. We assessed the effect of smoking on outcomes following arthroplasty. Patients and methods — We identified THAs and TKAs from the Clinical Practice Research Datalink, which were linked with datasets from Hospital Episode Statistics and the Office for National Statistics to identify outcomes. The effect of smoking on postoperative outcomes (complications, medications, revision, mortality, patient-reported outcome measures [PROMs]) was assessed using adjusted regression models. Results — We studied 60,812 THAs and 56,212 TKAs (11% smokers, 33% ex-smokers, 57% non-smokers). Following THA, smokers had an increased risk of lower respiratory tract infection (LRTI) and myocardial infarction compared with non-smokers and ex-smokers. Following TKA, smokers had an increased risk of LRTI compared with non-smokers. Compared with non-smokers (THA relative risk ratio [RRR] = 0.65; 95% CI = 0.61–0.69; TKA RRR = 0.82; CI = 0.78–0.86) and ex-smokers (THR RRR = 0.90; CI = 0.84–0.95), smokers had increased opioid usage 1-year postoperatively. Similar patterns were observed for weak opioids, paracetamol, and gabapentinoids. 1-year mortality rates were higher in smokers compared with non-smokers (THA hazard ratio [HR] = 0.37, CI = 0.29–0.49; TKA HR = 0.52, CI = 0.34–0.81) and ex-smokers (THA HR = 0.53, CI = 0.40–0.70). Long-term revision rates were not increased in smokers. Smokers had improvement in PROMs compared with preoperatively, with no clinically important difference in postoperative PROMs between smokers, non-smokers, and ex-smokers. Interpretation — Smoking is associated with more medical complications, higher analgesia usage, and increased mortality following arthroplasty. Most adverse outcomes were reduced in ex-smokers, therefore smoking cessation should be encouraged before arthroplasty

Quantifying the natural history of post-radical prostatectomy incontinence using objective pad test data

BACKGROUND: Urinary incontinence (UI) following radical prostatectomy is a well-recognized risk of the surgery. In most patients post-operative UI improves over time. To date, there is limited objective, quantitative data on the natural history of the resolution of post-prostatectomy UI. The purpose of this study was to define the natural history of post radical prostatectomy incontinence using an objective quantitative tool, the 1-hour standard pad test. METHODS: 203 consecutive patients underwent radical prostatectomy by a single surgeon between 03/98 & 08/03. A standardized 1-hour pad test was administered at subsequent postoperative clinic visits. The gram weight of urine loss was recorded and subdivided into four groups defined according to the grams of urine loss: minimal (<1 g), mild (>1, <10 g), moderate (10–50 g) and severe (>50 g). Patients were evaluated: at 2 weeks (catheter removal), 6 weeks, 18 weeks, 30 weeks, 42 weeks and 54 weeks. The data set was analyzed for average urine loss as well as grams of urine loss at each time point, the percentage of patients and the distribution of patients in each category. RESULTS: Mean follow up was 118 weeks. The majority of patients experienced incontinence immediately after catheter removal at 2 weeks that gradually improved with time. While continued improvement was noted to 1 year, most patients who achieved continence did so by 18 weeks post-op. CONCLUSION: While the majority of patients experience mild to severe UI immediately following catheter removal, there is a rapid decrease in leaked weight during the first 18 weeks following RRP. Patients continue to improve out to 1 year with greater than 90% having minimal leakage by International Continence Society criteria

Activation of synovial fibroblasts from patients at revision of their metal-on-metal total hip arthroplasty

BACKGROUND: The toxicity of released metallic particles generated in metal-on-metal (MoM) total hip arthroplasty (THA) using cobalt chromium (CoCr) has raised concerns regarding their safety amongst both surgeons and the public. Soft tissue changes such as pseudotumours and metallosis have been widely observed following the use of these implants, which release metallic by-products due to both wear and corrosion. Although activated fibroblasts, the dominant cell type in soft tissues, have been linked to many diseases, the role of synovial fibroblasts in the adverse reactions caused by CoCr implants remains unknown. To investigate the influence of implants manufactured from CoCr, the periprosthetic synovial tissues and synovial fibroblasts from patients with failed MoM THA, undergoing a revision operation, were analysed and compared with samples from patients undergoing a primary hip replacement, in order to elucidate histological and cellular changes. RESULTS: Periprosthetic tissue from patients with MoM implants was characterized by marked fibrotic changes, notably an increase in collagen content from less than 20% to 45-55%, an increase in α-smooth muscle actin positive cells from 4 to 9% as well as immune cells infiltration. Primary cell culture results demonstrated that MoM synovial fibroblasts have a decreased apoptosis rate from 14 to 6% compared to control synovial fibroblasts. In addition, synovial fibroblasts from MoM patients retained higher contractility and increased responsiveness to chemotaxis in matrix contraction. Their mechanical properties at a single cell level increased as observed by a 60% increase in contraction force and higher cell stiffness (3.3 kPa in MoM vs 2.18 kPa in control), as measured by traction force microscopy and atomic force microscopy. Further, fibroblasts from MoM patients promoted immune cell invasion by secreting monocyte chemoattractant protein 1 (MCP-1, CCL2) and induced monocyte differentiation, which could also be associated with excess accumulation of synovial macrophages. CONCLUSION: Synovial fibroblasts exposed in vivo to MoM THA implants that release CoCr wear debris displayed dramatic phenotypic alteration and functional changes. These findings unravelled an unexpected effect of the CoCr alloy and demonstrated an important role of synovial fibroblasts in the undesired tissue reactions caused by MoM THAs

Diagnostic guidelines for the histological particle algorithm in the periprosthetic neo-synovial tissue

Background The identification of implant wear particles and non-implant related particles and the characterization of the inflammatory responses in the periprosthetic neo-synovial membrane, bone, and the synovial-like interface membrane (SLIM) play an important role for the evaluation of clinical outcome, correlation with radiological and implant retrieval studies, and understanding of the biological pathways contributing to implant failures in joint arthroplasty. The purpose of this study is to present a comprehensive histological particle algorithm (HPA) as a practical guide to particle identification at routine light microscopy examination. Methods The cases used for particle analysis were selected retrospectively from the archives of two institutions and were representative of the implant wear and non-implant related particle spectrum. All particle categories were described according to their size, shape, colour and properties observed at light microscopy, under polarized light, and after histochemical stains when necessary. A unified range of particle size, defined as a measure of length only, is proposed for the wear particles with five classes for polyethylene (PE) particles and four classes for conventional and corrosion metallic particles and ceramic particles. Results All implant wear and non-implant related particles were described and illustrated in detail by category. A particle scoring system for the periprosthetic tissue/SLIM is proposed as follows: 1) Wear particle identification at light microscopy with a two-step analysis at low (× 25, × 40, and × 100) and high magnification (× 200 and × 400); 2) Identification of the predominant wear particle type with size determination; 3) The presence of non-implant related endogenous and/or foreign particles. A guide for a comprehensive pathology report is also provided with sections for macroscopic and microscopic description, and diagnosis. Conclusions The HPA should be considered a standard for the histological analysis of periprosthetic neo-synovial membrane, bone, and SLIM. It provides a basic, standardized tool for the identification of implant wear and non-implant related particles at routine light microscopy examination and aims at reducing intra-observer and inter-observer variability to provide a common platform for multicentric implant retrieval/radiological/histological studies and valuable data for the risk assessment of implant performance for regional and national implant registries and government agencies

Deep vein thrombosis following hip fracture surgery

Patients undergoing hip fracture surgery are at increased risk of deep vein thrombosis. There are limited studies of good quality assessing thromboprophylactic therapies in this patient population. Mechanical pumping devices may have a role in hip fracture patients, especially around the perioperative period, though compliance with these devices is a significant problem. Fondaparinux is the most effective pharmacological thromboprophylactic therapy following hip fracture surgery and can be used for extended prophylaxis after hospital discharge. A number of the recently published recommendations from the National Institute for Health and Clinical Excellence do not take into account the best available evidence specifically in patients undergoing hip fracture surgery, with findings from elective arthroplasty patients being extrapolated. Well-designed randomised trials are needed to determine the role of combined thromboprophylaxis, graduated compression stockings and newer oral anticoagulants so that appropriate recommendations can be made in patients undergoing hip fracture surgery. </jats:p