Aims

Cementless acetabular components rely on press-fit fixation for initial stability. In certain cases, initial stability is more difficult to obtain (such as during revision). No current study evaluates how a surgeon’s impaction technique (mallet mass, mallet velocity, and number of strikes) may affect component fixation. This study seeks to answer the following research questions: 1) how does impaction technique affect a) bone strain generation and deterioration (and hence implant stability) and b) seating in different density bones?; and 2) can an impaction technique be recommended to minimize risk of implant loosening while ensuring seating of the acetabular component?

The tissues surrounding 65 cemented and 36 cementless total joint replacements undergoing revision were characterised for cell types by immunohistochemistry and for cytokine expression by in situ hybridisation. We identified three distinct groups of revised implants: loose implants with ballooning radiological osteolysis, loose implants without osteolysis, and well-fixed implants. In the cemented series, osteolysis was associated with increased numbers of macrophages (p = 0.0006), T-lymphocyte subgroups (p = 0.03) and IL-1 (p = 0.02) and IL-6 (p = 0.0001) expression, and in the cementless series with increased numbers of T-lymphocyte subgroups (p = 0.005) and increased TNFα expression (p = 0.04). For cemented implants, the histological, histochemical and cytokine profiles of the interface correlated with the clinical and radiological grade of loosening and osteolysis. Our findings suggest that there are different biological mechanisms of loosening and osteolysis for cemented and cementless implants. T-lymphocyte modulation of macrophage function may be an important interaction at prosthetic interfaces

The coronavirus disease 2019 (COVID-19) pandemic has led to unprecedented challenges to healthcare systems worldwide. Orthopaedic departments have adopted business continuity models and guidelines for essential and non-essential surgeries to preserve hospital resources as well as protect patients and staff. These guidelines broadly encompass reduction of ambulatory care with a move towards telemedicine, redeployment of orthopaedic surgeons/residents to the frontline battle against COVID-19, continuation of education and research through web-based means, and cancellation of non-essential elective procedures. However, if containment of COVID-19 community spread is achieved, resumption of elective orthopaedic procedures and transition plans to return to normalcy must be considered for orthopaedic departments. The COVID-19 pandemic also presents a moral dilemma to the orthopaedic surgeon considering elective procedures. What is the best treatment for our patients and how does the fear of COVID-19 influence the risk-benefit discussion during a pandemic? Surgeons must deliberate the fine balance between elective surgery for a patient’s wellbeing versus risks to the operating team and utilization of precious hospital resources. Attrition of healthcare workers or Orthopaedic surgeons from restarting elective procedures prematurely or in an unsafe manner may render us ill-equipped to handle the second wave of infections. This highlights the need to develop effective screening protocols or preoperative COVID-19 testing before elective procedures in high-risk, elderly individuals with comorbidities. Alternatively, high-risk individuals should be postponed until the risk of nosocomial COVID-19 infection is minimal. In addition, given the higher mortality and perioperative morbidity of patients with COVID-19 undergoing surgery, the decision to operate must be carefully deliberated. As we ramp-up elective services and get “back to business” as orthopaedic surgeons, we have to be constantly mindful to proceed in a cautious and calibrated fashion, delivering the best care, while maintaining utmost vigilance to prevent the resurgence of COVID-19 during this critical transition period.

Cite this article: Bone Joint Open 2020;1-6:222–228.

We collected 16 samples of the membrane which surrounds loose hip prostheses from patients undergoing revision operations for aseptic loosening. To serve as the control group, samples of the synovial tissue and the fibrous capsular tissue were collected from 11 patients undergoing primary hip arthroplasties. Analyses of the expression levels of inducible nitric oxide synthase (iNOS), tumour necrosis factor-α (TNF-α), and cytosolic phospholipase A. 2. (cPLA. 2. ) mRNAs were performed by a reverse transcription polymerase chain reaction, and the content of nitrite was measured by the Griess reaction using sodium nitrite as the standard. The expression levels of iNOS, TNF-α, and cPLA. 2. mRNAs in the membranes were significantly higher than those in the control samples (p < 0.05). The expression levels of iNOS mRNA and the nitrite content in the membranes significantly correlated with those of TNF-α and cPLA. 2. mRNAs, respectively. In addition, the expression levels of iNOS, TNF-α, and cPLA. 2. mRNAs were significantly higher in membranes from cementless than in those from cemented implants (p < 0.05). Our results suggest that the expression levels of iNOS, TNF-α, and cPLA. 2. mRNAs in the membranes are regulated by closely-related mechanisms and that these have a significant role in aseptic loosening

Aims

Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasty (TKA). However, if the diaphysis has been previously violated, the resultant sclerotic canal can impair cemented stem fixation, which is vital for bone ingrowth into the cone, and long-term fixation. We report the outcomes of our solution to this problem, in which impaction grafting and a cemented stem in the diaphysis is combined with an uncemented metaphyseal cone, for revision TKA in patients with severely compromised bone.

Aims

To investigate the effect of polyethylene manufacturing characteristics and irradiation dose on the survival of cemented and reverse hybrid total hip arthroplasties (THAs).

We compared the radiological appearances and survival of four methods of fixation of a femoral stem in 538 hips after follow-up for five or ten years. The fixation groups were: 1) press-fit shot-blasted smooth Ti-Al-V stem; 2) press-fit shot-blasted proximally ridged stem; 3) proximal hydroxyapatite (HA) coating; and 4) cementing. Survival analysis at five to ten years showed better results in the HA-coated (100% at five to six years) and cemented stems (100% at 5 to 6 years) than in the two press-fit groups. There was a higher mean rate of migration in the smooth and ridged Ti-Al-V shot-blasted press-fit groups (0.8 mm/year and 0.6 mm/year, respectively) when compared with the HA-coated and cemented prostheses (both 0.3 mm/year). More radiolucent lines and osteolytic lesions were seen in the press-fit groups than in either the HA-coated or cemented implants, with a trend for a lower incidence of both in the HA compared with the cemented group. Proximal osteopenia increased in the press-fit and cemented prostheses with time, but did not do so in the HA group. There was a higher incidence of resorption of the femoral neck with time in the cemented group than in the other three. We conclude that the HA and the cemented interfaces both provide secure fixation with a trend in favour of HA. The cemented prosthesis meets the suggested National Institutes of Health definition of ‘efficacious’ at ten years

A heavy infiltrate of foreign-body macrophages is commonly seen in the fibrous membrane which surrounds an aseptically loose cemented implant. This is in response to particles of polymethylmethacrylate (PMMA) bone cement and other biomaterials. We have previously shown that monocytes and macrophages responding to particles of bone cement are capable of differentiating into osteoclastic cells which resorb bone. To determine whether the radio-opaque additives barium sulphate (BaSO. 4. ) and zirconium dioxide (ZrO. 2. ) influence this process, particles of PMMA with and without these agents were added to mouse monocytes and cocultured with osteoblast-like cells on bone slices. Osteoclast differentiation, as shown by the presence of the osteoclast-associated enzyme tartrate-resistant acid phosphatase (TRAP) and lacunar bone resorption, was observed in all cocultures. The addition of PMMA alone to these cocultures caused no increase in TRAP expression or bone resorption relative to control cocultures. Adding PMMA particles containing BaSO. 4. or ZrO. 2. , however, caused an increase in TRAP expression and a highly significant increase in bone resorption. Particles containing BaSO. 4. were associated with 50% more bone resorption than those containing ZrO. 2. . Our results suggest that radio-opaque agents in bone cement may contribute to the bone resorption of aseptic loosening by enhancing macrophage-osteoclast differentiation, and that PMMA containing is BaSO. 4. likely to be associated with more osteolysis than that containing ZrO. 2.

Proponents of the biological theory of aseptic loosening have in recent years tended to concentrate on the production and distribution of particulate ultra-high-molecular-weight polyethylene (UHMWPE) debris around the potential joint space. However, mechanical loading of cemented implants with the differing elastic moduli of metal stems, polymethylmethacrylate (PMMA) cement and bone can result in relative micromotion, implying the potential for production of metal and PMMA particles from the stem-cement interface by fretting wear. In order to investigate the production and biological reactivity of debris from this interface, PMMA and metal particulate debris was produced by sliding wear of PMMA pins containing barium sulphate and zirconium dioxide against a Vaquasheened stainless steel counterface. This debris was characterised by SEM, energy-dispersive analysis by X-ray (EDAX) and image analysis, then added to cell cultures of a human monocytic cell line, U937, and stimulation of pro-osteolytic cytokines measured by ELISA. Large quantities of PMMA cement debris were generated by the sliding wear of PMMA pins against Vaquasheened stainless steel plates in the method developed for this study. Both cements stimulated the release of pro-osteolytic TNFα from the U937 monocytic cell line, in a dose-dependent fashion. There was a trend towards greater TNFα release with Palacos cement than CMW cement at the same dose. Palacos particles also caused significant release of IL-6, another pro-osteolytic cytokine, while CMW did not. The particulate cement debris produced did not stimulate the release of GM-CSF or IL1β from the U937 cells. These results may explain the cytokine pathway responsible for bone resorption caused by particulate PMMA debris. Radio-opaque additives are of value in surgical practice and clinical studies to quantify the relevance of these in vitro findings are required before the use of cement containing radio-opacifier is constrained

An analysis of the cement mantle obtained with the Exeter impaction allografting system at one centre showed that it was either deficient or absent in almost 47% of Gruen zones. We therefore examined the mantle obtained using this system at another hospital and compared the results with those from the CPT and Harris Precoat Systems at other centres. The surgical indications for the procedure and the patient details were broadly similar in all four hospitals. There was some variation in the frequency of use of cortical strut allografts, cerclage wires and wire mesh to supplement the impaction allograft. Analysis of the cement mantles showed that when uncertain Gruen zones were excluded, the incidence of zones with areas of absence or deficiency of the cement was 47% and 50%, respectively, for the two centres using the Exeter system, 21% for the CPT system and 18% for the Harris Precoat system. We measured the difference in size between the proximal allograft impactors and the definitive prosthesis for each system. The Exeter system impactors are shorter than the definitive prosthesis and taper sharply so that the cavity created is inadequate, especially distally. The CPT proximal impactors are considerably longer than the definitive prosthesis and are designed to give a mantle of approximately 2 mm medially and laterally and 1.5 mm anteriorly and posteriorly. The Harris Precoat proximal impactors allow for a mantle with a circumference of 0.75 mm in the smaller sizes and 1 mm in the larger. Many reports link the longevity of a cemented implant to the adequacy of the cement mantle. For this reason, femoral impaction systems require careful design to achieve a cement mantle which is uninterrupted in its length and adequate in its thickness. Our results suggest that some current systems require modification

Aims

Our objective is to describe our early and mid-term results with the use of a new simple primary knee prosthesis as an articulating spacer in planned two-stage management for infected knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a complete two-stage revision.

Aims

While patients with psychological distress have poorer short-term outcomes after total knee arthroplasty (TKA), their longer-term function is unknown. We aimed to 1) assess the influence of preoperative mental health status on long-term functional outcomes, quality of life, and patient satisfaction; and 2) analyze the change in mental health after TKA, in a cohort of patients with no history of mental health disorder, with a minimum of ten years’ follow-up.

Aims

We compared implant and patient survival following intraoperative periprosthetic femoral fractures (IOPFFs) during primary total hip arthroplasty (THA) with matched controls.

We evaluated the impact of pre-coating the tibial component with polymethylmethacrylate (PMMA) on implant survival in a cohort of 16 548 primary NexGen total knee replacements (TKRs) in 14 113 patients. In 13 835 TKRs a pre-coated tray was used while in 2713 TKRs the non-pre-coated version of the same tray was used. All the TKRs were performed between 2001 and 2009 and were cemented. TKRs implanted with a pre-coated tibial component had a lower cumulative survival than those with a non-pre-coated tibial component (p = 0.01). After adjusting for diagnosis, age, gender, body mass index, American Society of Anesthesiologists grade, femoral coupling design, surgeon volume and hospital volume, pre-coating was an independent risk factor for all-cause aseptic revision (hazard ratio 2.75, p = 0.006). Revision for aseptic loosening was uncommon for both pre-coated and non-pre-coated trays (rates of 0.12% and 0%, respectively). Pre-coating with PMMA does not appear to be protective of revision for this tibial tray design at short-term follow-up. Cite this article: Bone Joint J 2013;95-B:367–70

Aims

Radiostereometric analysis (RSA) studies of vitamin E-doped, highly crosslinked polyethylene (VEPE) liners show low head penetration rates in cementless acetabular components. There is, however, currently no data on cemented VEPE acetabular components in total hip arthroplasty (THA). The aim of this study was to evaluate the safety of a new cemented VEPE component, compared with a conventional polyethylene (PE) component regarding migration, head penetration, and clinical results.

Aims

Early implant migration measured with radiostereometric analysis (RSA) has been proposed as a useful predictor of long-term fixation of tibial components in total knee arthroplasty. Evaluation of actual long-term fixation is of interest for cemented components, as well as for cementless fixation, which may offer long-term advantages once osseointegration has occurred. The objective of this study was to compare the long-term migration with one- and two-year migration to evaluate the predictive ability of short-term migration data and to compare migration and inducible displacement between cemented and cementless (porous metal monoblock) components at least ten years postoperatively.

Aims

Antifibrinolytic agents, including tranexamic acid (TXA) and epsilon-aminocaproic acid (EACA), have been shown to be safe and effective for decreasing perioperative blood loss and transfusion following total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, there are few prospective studies that directly compare these agents. The purpose of this study was to compare the benefits of intraoperative intravenous TXA with EACA.

Aims

The aim of this study was to investigate mortality and risk of intraoperative medical complications depending on delay to hip fracture surgery by using data from the Norwegian Hip Fracture Register (NHFR) and the Norwegian Patient Registry (NPR).