Aims. Early evidence has emerged suggesting that ceramic-on-ceramic articulations induce a different tissue reaction to ceramic-on-polyethylene and metal-on-metal bearings. Therefore, the aim of this study was to investigate the tissue reaction and cellular response to ceramic total hip arthroplasty (THA) materials in vitro, as well as the tissue reaction in capsular tissue after revision surgery of ceramic-on-ceramic THAs. Patients and Methods. We investigated tissue collected at revision surgery from nine ceramic-on-ceramic articulations. we compared our findings with tissue obtained from five metal-on-metal THA revisions, four ceramic-on-polyethylene THAs, and four primary osteoarthritis synovial membranes. The latter were analyzed to assess the amount of tissue fibrosis that might have been present at the time of implantation to enable evaluation, in relation to implantation time, of any subsequent response in the tissues. Results. There was a significant increase in tissue fibrosis with implantation time for all implant types tested. Interestingly, the tissue fibrosis in ceramic-on-ceramic THAs was significantly increased compared with metal-on-metal and ceramic-on-polyethylene. Additionally, we found ceramic wear particles in the periprosthetic tissue of ceramic implants. Fibroblasts responded with expression of cytokines when cultured on alumina-toughened zirconia (ATZ) and zirconia-toughened alumina (ZTA) ceramic surfaces. This response was more pronounced on ATZ ceramics compared with ZTA ceramics. The same inflammatory response was observed with peripheral blood mononuclear cells (PBMCs) cultured on ZTA and ATZ. Conclusion. Our findings therefore, corroborate the previous findings that ceramic-on-ceramic periprosthetic revision tissue is fibrous and offer an explanation for this observation. We detected a long-term inflammatory response of PBMCs and an inflammatory response of fibroblasts to ATZ and ZTA ceramic. These findings partially explain the fibrotic tissue change in periprosthetic tissue of ceramic-on-ceramic bearings. Cite this article: Bone Joint J 2018;100-B:882–90

Dual Mobility (DM) Total Hip Replacements (THRs) were introduced to reduce dislocation risk, which is the most common cause of early revision. The in-vivo mechanics of these implants is not well understood, despite their increased use in both elective and trauma settings. Therefore, the aim of this study was to comprehensively assess retrieved DM polyethylene liners for signs of damage using visual inspection and semi-quantitative geometric assessment techniques. Retrieved DM liners (n=20) were visually inspected for the presence of seven established modes of polyethylene damage. If embedded debris was identified on the external surface, its material composition was characterised using energy-dispersive x-ray analysis (EDX). Additionally, each liner was geometrically assessed for signs of wear/deformation using a validated methodology. Visual inspection of the liners revealed that scratching and pitting were the most common damage modes on either surface. Burnishing was observed on 50% and 15% of the internal and external surfaces, respectively. In addition, embedded debris was identified on 25% of the internal and 65% of the external surfaces. EDX analysis of the debris identified several materials including iron, titanium, cobalt-chrome, and tantalum. Geometric analysis demonstrated highly variable damage patterns across the liners. The results of this study provide insight into the in-vivo mechanics of DM bearings. For example, the results suggest that the internal bearing (i.e., between the head and liner) acts as the primary articulation site for DM-THRs as evidenced by a higher incidence of burnishing and larger, more concentrated regions of penetration across the liners’ internal surfaces. Furthermore, circumferential, and crescent-shaped damage patterns were identified on the articulating surfaces of the liners thus providing evidence that these components can rotate within the acetabular shell with varying degrees of mobility. The mechanics of DM bearings are complex and may be influenced by several factors (e.g., soft tissue fibrosis, patient activities) and thus further investigation is warranted. Finally, the results of this study suggest that DM liners may be susceptible to ex-vivo surface damage and thus caution is advised when handling and/or assessing these types of components

Introduction. Patients with aseptic loosening, a cause of failure in uncemented total joint arthroplasty (TJA), often present with fibrous tissue at the bone-implant interface. 1. In this study, we characterize the presence of neutrophil extracellular traps (NETs) in the intramedullary fibrotic membrane of aseptic loosening patients. We further explore the role of NETs, mediated by peptidyl arginine deiminase (PAD4), in peri-implant fibrosis and osseointegration failure through a murine model of unstable tibial implantation. 2–4. Methods. Peri-implant membrane was retrieved from five patients during total hip revision surgery and analyzed for the presence of NETs (citH3+ with extracellular DNA) via immunofluorescence. A Ti-6Al-4V implant was inserted in an oversized drill-hole in the right proximal tibia of 8-week-old C57BL/6J and PAD4 knockout mice (n=3 per group). Fourteen days later, all mice were euthanized, and implanted tibias were dissected. Fibrosis and osseointegration at the bone-implant interface were assessed by micro-computed tomography (microCT) and hematoxylin and eosin (H&E) staining. H&E samples were scored blindly by the investigator and another observer for signs of poor (score=0) to excellent osseointegration (score=3) using a rubric established in our lab. Results. NETs were found in peri-implant membrane collected from aseptic loosening patients (Figure 1a) and at the bone-implant interface in a murine model (Figure 1b). Unstable implants in wild type mice failed to osseointegrate, indicated by presence of fibroblast-like cells (dashed arrow), immature bone matrix (Figure 1c), low bone volume fraction (BV/TV) and bone surface area (BS) (Figure 1e). Unstable implants in PAD4. −/−. mice showed signs of good osseointegration such as mature trabeculae (solid arrow) (Figure 1d), higher BV/TV (p<0.10) and BS (p<0.05) (Figure 1f). Histological osseointegration scoring indicated wildtype mice exhibited an average score of 0.83 and PAD4. −/−. exhibited an average score of 2.5 (p<0.05, weighted Cohen's kappa = 0.714) (Figure 1g). Conclusion. NETs were characterized in fibrotic tissue in both aseptic loosening patients and in a murine model of unstable tibial implantation. NET inhibition was able to successfully prevent peri-implant fibrosis and osseointegration failure, leading the way for a potential novel non-invasive therapeutic approach for the treatment of aseptic loosening. For any figures, tables, or references, please contact the authors directly

Aims

In order to release the contracture band completely without damaging normal tissues (such as the sciatic nerve) in the surgical treatment of gluteal muscle contracture (GMC), we tried to display the relationship between normal tissue and contracture bands by magnetic resonance neurography (MRN) images, and to predesign a minimally invasive surgery based on the MRN images in advance.

Aims

Our objective was describing an algorithm to identify and prevent vascular injury in patients with intrapelvic components.

Aims

A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach.

Aims

Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).

Aims

Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Pad4^-/- mice that display defects in peptidyl arginine deiminase 4 (PAD4), an essential protein required for NETs) or resolution (via DNase 1 treatment, an enzyme that degrades the cytotoxic DNA matrix) of NETs can prevent osseointegration failure and formation of peri-implant fibrotic tissue.

Aims

Developmental dysplasia of the hip (DDH) is a complex musculoskeletal disease that occurs mostly in children. This study aimed to investigate the molecular changes in the hip joint capsule of patients with DDH.

Aims

One-stage revision hip arthroplasty for periprosthetic joint infection (PJI) has several advantages; however, resection of the proximal femur might be necessary to achieve higher success rates. We investigated the risk factors for resection and re-revisions, and assessed complications and subsequent re-revisions.

Aims

Cardiac magnetic resonance (CMR) was used to assess whether cardiac function or tissue composition was affected in patients with well-functioning metal-on-metal hip resurfacing arthroplasties (MoMHRA) when compared with a group of controls, and to assess if metal ion levels correlated with any of the functional or structural parameters studied.

Objectives

The purpose of this study was to compare the thickness of the hip capsule in patients with surgical hip disease, either with cam-femoroacetabular impingement (FAI) or non-FAI hip pathology, with that of asymptomatic control hips.

Aims

We aimed to assess the influence of ethnicity on the incidence of heterotopic ossification (HO) after total hip arthroplasty (THA).

Arthroscopy of the native hip is an established diagnostic and therapeutic procedure. Its application in the symptomatic replaced hip is still being explored. We describe the use of arthroscopy of the hip in 24 symptomatic patients following total hip replacement, resurfacing arthroplasty of the hip and partial resurfacing (study group), and compared it with arthroscopy of the native hip in 24 patients (control group). A diagnosis was made or confirmed at arthroscopy in 23 of the study group and a therapeutic arthroscopic intervention resulted in relief of symptoms in ten of these. In a further seven patients it led to revision hip replacement. In contrast, arthroscopy in the control group was diagnostic in all 24 patients and the resulting arthroscopic therapeutic intervention provided symptomatic relief in 21.

The mean operative time in the study group (59.7 minutes (35 to 93)) was less than in the control group (71 minutes (40 to 100), p = 0.04) but the arthroscopic approach was more difficult in the arthroplasty group. We suggest that arthroscopy has a role in the management of patients with a symptomatic arthroplasty when other investigations have failed to provide a diagnosis.

Total hip replacement (THR) still is a rare intervention in many African countries. In Burkina Faso it is not performed on a regular basis. A visiting programme for THR was started in a district hospital with no previous relevant experience. In this paper we present an analysis of the surgical technical problems and peri-operative complications of 152 THRs in 136 patients and three bipolar hemiarthroplasties in three patients undertaken in this new programme with limited orthopaedic equipment. There were 86 male and 53 female patients with a mean age of 49 years (21 to 78). We identified 77 intra-operative technical problems in 51 operations. There were 24 peri-operative complications in 21 patients, 17 of which were bony in nature. So far, ten revision THRs have been performed in nine patients.

Regular analysis of the technical problems and complications was used to improve quality, and we identified patient selection adapted to the local circumstances as important to avoid complications. Our reflections on the problems encountered in initiating such a programme may be of help to other teams planning similar projects.

Cite this article: Bone Joint J 2014;96-B:177–80.

Symptomatic cobalt toxicity from a failed total hip replacement is a rare but devastating complication. It has been reported following revision of fractured ceramic components, as well as in patients with failed metal-on-metal articulations. Potential clinical findings include fatigue, weakness, hypothyroidism, cardiomyopathy, polycythaemia, visual and hearing impairment, cognitive dysfunction, and neuropathy. We report a case of an otherwise healthy 46-year-old patient, who developed progressively worsening symptoms of cobalt toxicity beginning approximately six months following synovectomy and revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. The whole blood cobalt levels peaked at 6521 µg/l. The patient died from cobalt-induced cardiomyopathy. Implant retrieval analysis confirmed a loss of 28.3 g mass of the cobalt–chromium femoral head as a result of severe abrasive wear by ceramic particles embedded in the revision polyethylene liner. Autopsy findings were consistent with heavy metal-induced cardiomyopathy.

We recommend using new ceramics at revision to minimise the risk of wear-related cobalt toxicity following breakage of ceramic components.

Cite this article: Bone Joint J 2013;95-B:31–7.

Four uncemented Symax hip stems were extracted at three weeks and nine, 13 and 32 months, respectively, for reasons other than loosening. The reasons for implant removal were infection in two cases, recurrent dislocation in one and acetabular fracture in one. They were analysed to assess the effect and behaviour of an electrochemically deposited, completely resorbable biomimetic BONIT-hydroxyapatite (HA) coating (proximal part) and a DOTIZE surface treatment (distal part) using qualitative histology, quantitative histomorphometry and scanning electron microscopy (SEM). Early and direct bone-implant bonding with signs of active remodelling of bone and the HA coating were demonstrated by histology and SEM. No loose BONIT-HA particles or delamination of the coating were observed, and there was no inflammation or fibrous interposition at the interface.

Histomorphometry showed bone-implant contact varying between 26.5% at three weeks and 83.5% at 13 months at the HA-coated implant surface. The bone density in the area of investigation was between 24.6% at three weeks and 41.1% at 32 months. The DOTIZE surface treatment of the distal part of the stem completely prevented tissue and bone apposition in all cases, thereby optimising proximal stress transfer.

The overall features of this implant, in terms of geometry and surface texture, suggest a mechanically stable design with a highly active biomimetic coating, resulting in rapid and extensive osseo-integration, exclusively in the metaphyseal part of the stem. Early remodelling of the HA coating does not seem to have a detrimental effect on short-term bone-implant coupling. There were no adverse effects identified from either the BONIT-HA coating or the DOTIZE surface treatment.

We sought to establish the incidence of joint failure secondary to adverse reaction to metal debris (ARMD) following metal-on-metal hip resurfacing in a large, three surgeon, multicentre study involving 4226 hips with a follow-up of 10 to 142 months. Three implants were studied: the Articular Surface Replacement; the Birmingham Hip Resurfacing; and the Conserve Plus. Retrieved implants underwent analysis using a co-ordinate measuring machine to determine volumetric wear. There were 58 failures associated with ARMD. The median chromium and cobalt concentrations in the failed group were significantly higher than in the control group (p < 0.001). Survival analysis showed a failure rate in the patients with Articular Surface Replacement of 9.8% at five years, compared with < 1% at five years for the Conserve Plus and 1.5% at ten years for the Birmingham Hip Resurfacing. Two ARMD patients had relatively low wear of the retrieved components. Increased wear from the metal-on-metal bearing surface was associated with an increased rate of failure secondary to ARMD. However, the extent of tissue destruction at revision surgery did not appear to be dose-related to the volumetric wear.

In patients with severe quadriplegic cerebral palsy and painful hip dislocation proximal femoral resection arthroplasty can reduce pain, but the risk of heterotopic ossification is significant. We present a surgical technique of autologous capping of the femoral stump in order to reduce this risk, using the resected femoral head as the graft.

A retrospective study of 31 patients (43 hips) who had undergone proximal femoral resection arthroplasty with (29 hips) and without autologous capping (14 hips) was undertaken. Heterotopic ossification was less frequent in patients with autologous capping, and a more predictable pattern of bony overgrowth was found.

For a selected group of non-ambulatory patients with long-standing painful dislocation of the hip, we recommend femoral resection arthroplasty over more complicated reconstructive operations. The risk of heterotopic ossification, which is a major disadvantage of this operation, is reduced by autologous capping.

Inflammatory pseudotumours occasionally occur after metal-on-metal hip resurfacing and often lead to revision. Our aim was to determine the severity of this complication by assessing the outcome of revision in these circumstances and by comparing this with the outcome of other metal-on-metal hip resurfacing revisions as well as that of matched primary total hip replacements.

We identified 53 hips which had undergone metal-on-metal hip resurfacing and required revision at a mean of 1.59 years (0.01 to 6.69) after operation. Of these, 16 were revised for pseudotumours, 21 for fracture and 16 for other reasons. These were matched by age, gender and diagnosis with 103 patients undergoing primary total hip replacement with the Exeter implant.

At a mean follow-up of three years (0.8 to 7.2) the outcome of metal-on-metal hip resurfacing revision for pseudotumour was poor with a mean Oxford hip score of 20.9 (sd 9.3) and was significantly worse (p < 0.001) than the outcome for fracture with a mean Oxford hip score of 40.2 (sd 9.2) or that for other causes with a mean Oxford hip score of 37.8 (sd 9.4). The clinical outcome of revision for pseudotumour was also significantly worse (p < 0.001) than the outcome of matched primary total hip replacements. By contrast, the outcome for fracture and other causes was not significantly different from that of matched primary total hip replacements (p = 0.065). After revision for pseudotumour there were three cases of recurrent dislocation, three of palsy of the femoral nerve, one of stenosis of the femoral artery and two of loosening of the component. Five hips required further revision. In three of these there was evidence of recurrent pseudotumour, and one is currently awaiting further revision. The incidence of major complications after revision for pseudotumour (50%) was significantly higher (p = 0.018) than that after revision for other causes (14%).

The outcome of revision for pseudotumour is poor and consideration should be given to early revision to limit the extent of the soft-tissue destruction. The outcome of resurfacing revision for other causes is good.