Systematic review and meta-analysis of the reliability and discriminative validity of cartilage compositional MRI in knee osteoarthritis.

OBJECTIVE: To assess reliability and discriminative validity of cartilage compositional magnetic resonance imaging (MRI) in knee osteoarthritis (OA). DESIGN: The study was carried out per PRISMA recommendations. We searched MEDLINE and EMBASE (1974 - present) for eligible studies. We performed qualitative synthesis of reliability data. Where data from at least two discrimination studies were available, we estimated pooled standardized mean difference (SMD) between subjects with and without OA. Discrimination analyses compared controls and subjects with mild OA (Kellgren-Lawrence (KL) grade 1-2), severe OA (KL grade 3-4) and OA not otherwise specified (NOS) where not possible to stratify. We assessed quality of the evidence using Quality Appraisal of Diagnostic Reliability (QAREL) and Quality Assessment of Diagnostic Accuracy (QUADAS-2) tools. RESULTS: Fifty-eight studies were included in the reliability analysis and 26 studies were included in the discrimination analysis, with data from a total of 2,007 knees. Intra-observer, inter-observer and test-retest reliability of compositional techniques were excellent with most intraclass correlation coefficients >0.8 and coefficients of variation <10%. T1rho and T2 relaxometry were significant discriminators between subjects with mild OA and controls, and between subjects with OA (NOS) and controls (P < 0.001). T1rho showed best discrimination for mild OA (SMD [95% CI] = 0.73 [0.40 to 1.06], P < 0.001) and OA (NOS) (0.60 [0.41 to 0.80], P < 0.001). Quality of evidence was moderate for both parts of the review. CONCLUSIONS: Cartilage compositional MRI techniques are reliable and, in the case of T1rho and T2 relaxometry, can discriminate between subjects with OA and controls.

No difference in patellar tracking between symmetrical and asymmetrical femoral component designs in TKA.

PURPOSE: Poor knee extension function after total knee arthroplasty (TKA) is associated with factors including articular geometry and alignment. Femoral trochlear geometry has evolved from symmetrical to become more prominent proximal-laterally, with the groove aligned proximal-lateral to distal-medial. This study in vitro tested the hypothesis that a modern asymmetrical prosthesis would restore patellar tracking and stability to more natural behaviour than an older symmetrical prosthesis. METHODS: Six knees had their patellar tracking measured optically during active knee extension. Medial-lateral force versus displacement stability was measured at fixed angles of knee flexion. The measurements were repeated after inserting each of the symmetrical and asymmetrical TKAs. RESULTS: Significant differences of patellar lateral displacement stability, compared to normal, were not found at any angle of knee flexion. The patella tracked medial-laterally within 2.5 mm of the natural path with both TKAs. However, for both TKAs near knee extension, the patella was tilted laterally by approximately 6° and was also flexed approximately 8° more than in the natural knee. CONCLUSION: The hypothesis was not supported: The more anatomical component design did not provide more anatomical patellar kinematics and stability.

Outcome following knee arthroplasty beyond 15 years.

There is a paucity of information detailing functional outcome following total knee arthroplasty for this length of follow-up. We collected data from 187 knees in 150 surviving patients, beyond 15 years from implantation. Survival of the implant was confirmed and a patient administered questionnaire including WOMAC, SF-36 and patient satisfaction was used, data was scrutinised for differences between primary and revision knee surgery. Seventy knees were revised at a mean of 10.8 years. The mean WOMAC Pain score was 72 indicating predominantly mild pain. The mean WOMAC Function scores were lower at 55 indicating moderate limitation of most activities. No significant differences were found between revised and un-revised patients. Long-term pain and satisfaction scores in this population were good illustrating the benefits of TKA in the long term even in patients who have undergone revision surgery.

Multi- and univariate analyses of the weekend effect for elective lower-limb joint replacements.

Introduction The weekend effect is a perceived difference in outcome between medical care provided at the weekend when compared to that of a weekday. Clearly multifactorial, this effect remains incompletely understood and variable in different clinical contexts. In this study we analyse factors relevant to the weekend effect in elective lower-limb joint replacement at a large NHS multispecialty academic healthcare centre. Materials and Methods We reviewed the electronic medical records of 352 consecutive patients who received an elective primary hip or knee arthroplasty. Patient, clinical and time-related variables were extracted from the records. The data were anonymised, then processed using a combination of uni- and multivariate statistics. Results There is a significant association between the selected weekend effect outcome measure (postoperative length of stay) and patient age, American Society of Anesthesiologists classification, time to first postoperative physiotherapy and time to postoperative radiography but not day of the week of operation. Discussion We were not able to demonstrate a weekend effect in elective lower-limb joint replacement at our institution nor identify a factor that would require additional weekend clinical medical staffing. Rather, resource priorities would seem to include measures to optimise at-risk patients preoperatively and measures to reduce time to physiotherapy and radiography postoperatively. Conclusions Our findings imply that postoperative length of stay could be minimised by strategies relating to patient selection and access to postoperative services. We have also identified a powerful statistical methodology that could be applied to other service evaluations in different clinical contexts.

Neuroarthropathy in diabetes: pathogenesis of Charcot arthropathy.

Charcot neuroarthropathy is a rare but serious complication of diabetes, causing progressive destruction of the bones and joints of the foot leading to deformity, altered biomechanics and an increased risk of ulceration. Management is complicated by a lack of consensus on diagnostic criteria and an incomplete understanding of the pathogenesis. In this review, we consider recent insights into the development of Charcot neuroarthropathy. It is likely to be dependent on several interrelated factors which may include a genetic pre-disposition in combination with diabetic neuropathy. This leads to decreased neuropeptides (nitric oxide and calcitonin gene-related peptide), which may affect the normal coupling of bone formation and resorption, and increased levels of Receptor activator of nuclear factor kappa-B ligand, potentiating osteoclastogenesis. Repetitive unrecognized trauma due to neuropathy increases levels of pro-inflammatory cytokines (interleukin-1ß, interleukin-6, tumour necrosis factor α) which could also contribute to increased bone resorption, in combination with a pre-inflammatory state, with increased autoimmune reactivity and a profile of monocytes primed to transform into osteoclasts - cluster of differentiation 14 (CD14). Increased blood glucose and loss of circulating Receptor for Advanced Glycation End-Products (AGLEPs), leading to increased non-enzymatic glycation of collagen and accumulation of AGLEPs in the tissues of the foot, may also contribute to the pathological process. An understanding of the relative contributions of each of these mechanisms and a final common pathway for the development of Charcot neuroarthropathy are still lacking. Cite this article: S. E. Johnson-Lynn, A. W. McCaskie, A. P. Coll, A. H. N. Robinson. Neuroarthropathy in diabetes: pathogenesis of Charcot arthropathy. Bone Joint Res 2018;7:373-378. DOI: 10.1302/2046-3758.75.BJR-2017-0334.R1.

Removal of acetabular bone in resurfacing arthroplasty of the hip: a comparison with hybrid total hip arthroplasty.

Resurfacing arthroplasty of the hip is being performed more frequently in the United Kingdom. The majority of these patients are younger than 55 years of age, and in this group the key benefits include conservation of femoral bone stock and the potential reduction in the rate of dislocation afforded by the larger resurfacing head. Early aseptic loosening is well recognised in patients younger than 55 years of age, and proponents of resurfacing believe that the improved wear characteristics of the metal-on-metal bearing may improve the long-term survival of this implant. There has been some concern, however, that resurfacing may not be conservative of acetabular bone. We compared a series of 33 consecutive patients who had a hybrid total hip arthroplasty with an uncemented acetabular component and a cemented femoral implant, with 35 patients undergoing a Birmingham hip resurfacing arthroplasty. We compared the diameter of the implanted acetabulum in both groups and, because they were not directly comparable, we corrected for patient size by measuring the diameter of the contralateral femoral head. The data were analysed using unpaired t-tests and analysis of covariance. There was a significantly larger acetabulum in the Birmingham arthroplasty group (mean diameter 56.6 mm vs 52.0 mm; p < 0.001). However, this group had a significantly larger femoral head diameter on the contralateral side (p = 0.03). Analysis of covariance revealed a significant difference between the mean size of the acetabular component implanted in the two operations. The greatest difference in the size of acetabulum was in those patients with a larger diameter of the femoral head. This study shows that more bone is removed from the acetabulum in hip resurfacing than during hybrid total hip arthroplasty, a difference which is most marked in larger patients.

Should we reconsider all-polyethylene tibial implants in total knee replacement?

The role of modular tibial implants in total knee replacement is not fully defined. We performed a prospective randomised controlled clinical trial using radiostereophotogrammetric analysis to compare the performance of an all-polyethylene tibia with a metal-backed cruciate-retaining condylar design, PFC-Sigma total knee replacement for up to 24 months. There were 51 patients who were randomised into two treatment groups. There were 10 subsequent withdrawals, leaving 21 all-polyethylene and 20 metal-backed tibial implants. No patient was lost to follow-up. There were no significant demographic differences between the groups. At two years one metal-backed implant showed migration > 1 mm, but no polyethylene implant reached this level. There was a significant increase in the SF-12 and Oxford knee scores after operation in both groups. In an uncomplicated primary total knee replacement the all-polyethylene PFC-Sigma tibial prosthesis showed no statistical difference in migration from that of the metal-backed counterpart. There was no difference in the clinical results as assessed by the SF-12, the Oxford knee score, alignment or range of movement at 24 months, although these assessment measures were not statistically powered in this study.

Comparison of offset in Birmingham hip resurfacing and hybrid total hip arthroplasty.

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA). We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurfacing arthroplasty (BHR). We measured the femoral offset, femoral length, acetabular offset and acetabular height with reference to the normal contralateral hip. The data were analysed by paired t-tests. There was a significant reduction in femoral offset (p = 0.0004) and increase in length (p = 0.001) in the BHR group. In the THA group, there was a significant reduction in acetabular offset (p = 0.0003), but femoral offset and overall hip length were restored accurately. We conclude that hip resurfacing does not restore hip mechanics as accurately as THA.

From needle to knife.

Trauma and Orthopaedic care has been through a rapid evolution over the past few decades. This Editorial discusses some of the advances.

The use of digital X-ray radiogrammetry and peripheral dual energy X-ray absorptiometry in patients attending fracture clinic after distal forearm fracture.

Despite the fact that 50% of postmenopausal women with Colles' fracture have evidence of osteoporosis, the vast majority of women with forearm fractures are neither investigated nor treated for osteoporosis. Digital X-ray radiogrammetry (DXR) provides an attractive option in patients with distal forearm fracture, as it requires no additional X-rays over and above those performed as part of clinical management. We have compared DXR analysis of nonstandardised plain films taken routinely in accident and emergency with peripheral dual energy X-ray absorptiometry (pDXA) in a group presenting with distal forearm fracture. Women presenting with a fracture of the distal forearm underwent pDXA measurements of the calcaneus. Plain X-rays performed at the time of presentation were taken to allow adequate fracture treatment. No additional radiographer training or standardisation of films was performed. The DXR technique relies upon visualisation of the metacarpal shafts and this was not visualised on 123 of 201 (61%) films. The AP plain film was thus assessed using DXR for BMD in the remaining 78 patients with a mean age of 70.6 years (SE = 1.3). Mean BMD for DXR was 0.46 g/cm2 (SE = 0.01) and for pDXA was 0.40 g/cm2 (SE = 0.01). The correlation between BMD measured using the two techniques was 0.55 (P < 0.001). Although DXR measurements could not be performed in all patients, this proportion could easily be increased by routinely including the metacarpal shaft region in X-rays obtained after suspected distal forearm fracture. The correlation between the pDXA and DXR results is comparable with those reported between DXA measurements at the forearm, spine and hip. Our study suggests that DXR may provide a feasible method for the assessment of future fracture risk. The potential advantage of DXR over calcaneal pDXA measurements is that standard forearm X-ray obtained as part of fracture management could be used.

The inadequacy of standard radiographs in detecting flaws in the cement mantle.

Radiological assessment of the cement mantle is used routinely to determine the outcome of total hip replacement. We performed a simulated replacement arthroplasty on cadaver femora and took standard postoperative radiographs. The femora were then sectioned into 7 mm slices starting at the calcar, and high-resolution faxitron radiographs were taken of these sections. Analysis of the faxitron images showed that defects in the cement mantle were observed up to 100 times more frequently than on the standard films. We therefore encourage the search for a better technique in assessing the cement mantle.

Pre-heating of components in cemented total hip arthroplasty.

Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of septic loosening of cemented femoral components. Heating of the component to 44 degrees C is known to reduce the porosity of the cement-prosthesis interface. The temperature of the cement-bone interface was recorded intra-operatively as 32.3 degrees C. A simulated femoral model was devised to study the effect of heating of the component on the implant-cement interface. Heating of the implant and vacuum mixing have a synergistic effect on the porosity of the implant-cement interface, and heating also reverses the gradients of microhardness in the mantle. Heating of the implant also reduces porosity at the interface depending on the temperature. A minimum difference in temperature between the implant and the bone of 3 degrees C was required to produce this effect. The optimal difference was 7 degrees C, representing a balance between maximal reduction of porosity and an increased risk of thermal injury. Using contemporary cementing techniques, heating the implant to 40 degrees C is recommended to produce an optimum effect.

Radiological features predictive of aseptic loosening in cemented Charnley femoral stems.

The radiological features of the cement mantle around total hip replacements (THRs) have been used to assess aseptic loosening. In this case-control study we investigated the risk of failure of THR as predictable by a range of such features using data from patients recruited to the Trent Regional Arthroplasty Study (TRAS). An independent radiological assessment was undertaken on Charnley THRs with aseptic loosening within five years of surgery and on a control group from the TRAS database. Chi-squared tests were used to test the probability of obtaining the observed data by chance, and odds ratios were calculated to estimate the strength of association for different features. Several features were associated with a clinically important increase (>twofold) in the risk of loosening, which was statistically significant for four features (p < 0.01). Inadequate cementation (Barrack C and D grades) was the most significant feature, with an estimated odds ratio of 9.5 (95% confidence interval 3.2 to 28.4, p < 0.0001) for failure.

Single-photon-emission computerised tomography compared with planar bone scan to assess femoral head vascularity.

We performed single-photon-emission CT (SPECT) and planar bone scans to assess femoral head vascularity in ten patients with displaced intracapsular hip fracture. The heads were labelled with tetracycline and after excision at hemiarthroplasty were assessed for tetracycline uptake distribution by fluorescence under UV light. The four which had the greatest tetracycline uptake were normal on SPECT and planar imaging. In two cases the planar bone scans were normal although SPECT suggested avascularity thus giving false-negative results. Surgeons should be aware of this; SPECT may prove to be a more accurate method of assessing vascularity of the femoral head in fractures of the femoral neck.

Cement pressurisation during hip replacement.

The newer techniques of cementing aim to improve interlock between cement and bone around a femoral stem by combining high pressure and reduced viscosity. This may produce increased embolisation of fat and marrow leading to hypotension, impaired pulmonary gas exchange and death. For this reason the use of high pressures has been questioned. We compared finger-packing with the use of a cement gun by measuring intramedullary pressures during the cementing of 31 total hip replacements and measuring physiological changes in 19 patients. We also measured pressure in more detail in a laboratory model. In the clinical series the higher pressures were produced by using a gun, but this caused less physiological disturbance than finger-packing. The laboratory studies showed more consistent results with the gun technique, but for both methods of cementing the highest pressures were generated during the insertion of the stem of the prosthesis.

Radiological evaluation of the interfaces after cemented total hip replacement. Interobserver and intraobserver agreement.

Three radiological methods are commonly used to assess the outcome of total hip replacement (THR). They aim to record the appearance of lucent areas and migration of the prosthesis in a reproducible manner. Two of them were designed to monitor the implant through time and one to grade the quality of cementing. We have measured the level of inter- and intraobserver agreement in all three systems. We randomised 30 patients to receive either finger packing or retrograde gun cementing during Charnley hip replacements. The postoperative departmental radiographs were evaluated in a blinded study by two orthopaedic trainees, two consultants and two experts in THR. The trainees and consultants repeated the exercise at least two weeks later. We used the unweighted kappa statistic to establish the levels of agreement. In general, intraobserver agreement was moderate but interobserver agreement was poor, with levels similar to or less than those expected by chance. Our results indicate that such systems cannot provide reliable data from centres in different parts of the world, with various levels of surgeon evaluating radiographs at differing time intervals. We discuss the problem and suggest some methods of improvement.

Randomised, prospective study comparing cemented and cementless total knee replacement: results of press-fit condylar total knee replacement at five years.

Early implants for total knee replacement were fixed to bone with cement. No firm scientific reason has been given for the introduction of cementless knee replacement and the long-term survivorship of such implants has not shown any advantage over cemented forms. In a randomised, prospective study we have compared cemented and uncemented total knee replacement and report the results of 139 prostheses at five years. Outcome was assessed both clinically by independent examination using the Nottingham knee score and radiologically using the Knee Society scoring system. Independent statistical analysis of the data showed no significant difference between cemented and cementless fixation for pain, mobility or movement. There was no difference in the radiological alignment at five years, but there was a notable disparity in the radiolucent line score. With cemented fixation there was a significantly greater number of radiolucent lines on anteroposterior radiographs of the tibia and lateral radiographs of the femur. At five years, our clinical results would not support the use of the more expensive cementless fixation whereas the radiological results are of unknown significance. Longer follow-up will determine any changes in the results and conclusions.

Opsonization of polyethylene wear particles regulates macrophage and osteoblast responses in vitro.

The cellular reaction to wear debris may result in the failure of an artificial joint's fixation to the skeleton. The influence of debris opsinization on cell activity has received little attention. This study seeks to establish whether different proteinaceous culture environments may invoke variant cellular responses to debris challenge. Consideration of the zeta potential of a low density polyethylene particle group and an ex vitro ultrahigh molecular weight polyethylene particle group revealed that the nature of the protein adsorbants is related to the concentration of the proteins in solution. Furthermore, the composition of the adsorbed layer was shown to vary with the spectra of proteins in solution. In standard cell culture conditions zeta potential approached zero, indicating the high probability of particle agglomeration. Cell challenge studies with U937 macrophages showed that BSA and FCS protein adsorption mediated increased cell adhesion, while bovine IgG showed little change over control values. No changes in behavior of osteoblastic cells were observed in similar experiments.

Human tissue retrieval at post-mortem for musculoskeletal research.

Laboratory experimentation must attempt to reduce animal involvement, and human cadaveric tissue can be a suitable alternative; however, this tissue is a potential biohazard, with the transmission of human immunodeficiency and hepatitis viruses presenting a very serious problem. In this paper we discuss how human tissue can be obtained at hospital post-mortem, and how it can then be stored and handled in a laboratory environment, focusing particularly on safety issues. We discuss the way in which the Department of Orthopaedic Surgery at Leicester University obtained human tissue for research into hip replacement. It is hoped that the article will serve as a 'blue-print' for other related research projects, where human tissue is required for experimentation.

Sectioning fresh human bone: the reduction of aerosol and physical hazards.

Musculoskeletal research demands an accurate model on which to work, and fresh frozen human bone is an ideal material. However, there is increasing concern over the biohazard that this represents. A method is reported that reduces the biohazard, and two research situations are described. Both use polymethylmethacrylate (PMMA) bone cement as an interface between the human tissue and the cutting device, which allows solid and suitable geometry for vice fixation. A method of bone cutting that enables remote operation is described; this method may reduce the risk of disease transmission by aerosol, and prove useful to all in this field of research.