Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles.

Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure. Bone Joint Res 2016;5:162–168. DOI: 10.1302/2046-3758.55.BJR-2016-0086.

Aims

The purpose of this study was to develop a prognostic model for predicting survival of patients undergoing surgery owing to metastatic bone disease (MBD) in the appendicular skeleton.

The August 2015 Oncology Roundup³⁶⁰ looks at: Glasgow prognostic score in soft-tissue sarcoma; Denosumab in giant cell tumour; Timing, complications and radiotherapy; Pigmented villonodular synovitis and arthroscopy; PATHFx: estimating survival in pathological cancer; Prosthetic lengthening of short stumps; Chondrosarcoma and pathological fracture

The October 2014 Hip & Pelvis Roundup³⁶⁰ looks at: functional acetabular orientation; predicting re-admission following THR; metal ions and resurfacing; lipped liners increase stability; all anaesthetics equal in hip fracture surgery; revision hip surgery in very young patients; and uncemented hips.

We have investigated in vitro the release kinetics and bioactivity of fibroblast growth factor-2 (FGF-2) released from a carrier of fibrin sealant. In order to evaluate the effects of the FGF-2 delivery mechanism on the repair of articular cartilage, full-thickness cylindrical defects, 5 mm in diameter and 4 mm in depth, which were too large to undergo spontaneous repair, were created in the femoral trochlea of rabbit knees. These defects were then filled with the sealant.

Approximately 50% of the FGF-2 was released from the sealant within 24 hours while its original bioactivity was maintained. The implantation of the fibrin sealant incorporating FGF-2 successfully induced healing of the surface with hyaline cartilage and concomitant repair of the subchondral bone at eight weeks after the creation of the defect.

Our findings suggest that this delivery method for FGF-2 may be useful for promoting regenerative repair of full-thickness defects of articular cartilage in humans.

We report the five year outcomes of a two-stage approach for infected total hip replacement. This is a single-surgeon experience at a tertiary centre where the more straightforward cases are treated using single-stage exchange. This study highlights the vital role of the multidisciplinary team in managing these cases.

A total of 125 patients (51 male, 74 female) with a mean age of 68 years (42 to 78) were reviewed prospectively. Functional status was assessed using the Harris hip score (HHS). The mean HHS improved from 38 (6 to 78.5) pre-operatively to 81.2 (33 to 98) post-operatively. Staphylococcus species were isolated in 85 patients (68%).

The rate of control of infection was 96% at five years. In all, 19 patients died during the period of the study. This represented a one year mortality of 0.8% and an overall mortality of 15.2% at five years. No patients were lost to follow-up.

We report excellent control of infection in a series of complex patients and infections using a two-stage revision protocol supported by a multidisciplinary approach. The reason for the high rate of mortality in these patients is not known.

Cite this article: Bone Joint J 2014;96-B:1312–18

Objectives

The aim of this study was to examine whether asymmetric loading influences macrophage elastase (MMP12) expression in different parts of a rat tail intervertebral disc and growth plate and if MMP12 expression is correlated with the severity of the deformity.

Systemic capillary leak syndrome, or the Clarkson syndrome, is an extremely rare condition in which increased capillary permeability results in a massive shift of fluid into the extravascular space. This is followed rapidly by hypotensive shock, haemoconcentration, and, potentially, substantial oedema of the limbs resulting in an acute compartment syndrome. It is important for orthopaedic surgeons to be aware of this syndrome as our medical colleagues, who initially care for these patients, are less familiar with the diagnosis and the need for emergency management of the associated compartment syndrome should it develop. There have been fewer than 100 cases of this entity reported.

This case report is the first to describe the subsequent development of a compartment syndrome in all four limbs. Clinical vigilance and continuous monitoring of intracompartmental pressure is necessary in these patients in order to help reduce limb-threatening complications.

Anthrax is extremely rare in the western world but is endemic to areas of south and central Asia. In early 2010 an outbreak was identified in heroin-injecting intravenous drug users in the United Kingdom and Europe. Afghanistan is currently the principal source of heroin which reaches the United Kingdom. When anthrax occurs, cutaneous disease accounts for over 95% of cases. At least 47 cases with 13 deaths have been confirmed so far. We present three cases presenting during this time with marked swelling, one resulting in compartment syndrome but all with an absence of the expected cutaneous appearances.

We suggest that rather than cutaneous anthrax, these patients represent a new subcutaneous presentation of anthrax.

A silver-containing hydroxyapatite (Ag-HA) coating has been developed using thermal spraying technology. We evaluated the osteoconductivity of this coating on titanium (Ti) implants in rat tibiae in relation to bacterial infection in joint replacement.

At 12 weeks, the mean affinity indices of bone formation of a Ti, an HA, a 3%Ag-HA and a 50%Ag-HA coating were 97.3%, 84.9%, 81.0% and 40.5%, respectively. The mean affinity indices of bone contact of these four coatings were 18.8%, 83.7%, 77.2% and 40.5%, respectively. The indices of bone formation and bone contact around the implant of the 3%Ag-HA coating were similar to those of the HA coating, and no significant differences were found between them (bone formation, p = 0.99; bone contact, p = 0.957). However, inhibition of bone formation was observed with the 50%Ag-HA coating.

These results indicate that the 3%Ag-HA coating has low toxicity and good osteoconductivity, and that the effect of silver toxicity on osteoconductivity depends on the dose.

Satisfactory primary wound healing following total joint replacement is essential. Wound healing problems can have devastating consequences for patients. Assessment of their healing capacity is useful in predicting complications. Local factors that influence wound healing include multiple previous incisions, extensive scarring, lymphoedema, and poor vascular perfusion. Systemic factors include diabetes mellitus, inflammatory arthropathy, renal or liver disease, immune compromise, corticosteroid therapy, smoking, and poor nutrition. Modifications in the surgical technique are necessary in selected cases to minimise potential wound complications. Prompt and systematic intervention is necessary to address any wound healing problems to reduce the risks of infection and other potential complications.

Cite this article: Bone Joint J 2013;95-B, Supple A:144–7.

We report the incidence of and risk factors for complications after scoliosis surgery in patients with Duchenne muscular dystrophy (DMD) and compare them with those of other neuromuscular conditions.

We identified 110 (64 males, 46 females) consecutive patients with a neuromuscular disorder who underwent correction of the scoliosis at a mean age of 14 years (7 to 19) and had a minimum two-year follow-up. We recorded demographic and peri-operative data, including complications and re-operations.

There were 60 patients with cerebral palsy (54.5%) and 26 with DMD (23.6%). The overall complication rate was 22% (24 patients), the most common of which were deep wound infection (9, 8.1%), gastrointestinal complications (5, 4.5%) and hepatotoxicity (4, 3.6%). The complication rate was higher in patients with DMD (10/26, 38.5%) than in those with other neuromuscular conditions (14/84, 16.7% (p = 0.019). All hepatotoxicity occurred in patients with DMD (p = 0.003), who also had an increased rate of deep wound infection (19% vs 5%) (p = 0.033). In the DMD group, no peri-operative factors were significantly associated with the rate of overall complications or deep wound infection. Increased intra-operative blood loss was associated with hepatotoxicity (p = 0.036).

In our series, correction of a neuromuscular scoliosis had an acceptable rate of complications: patients with DMD had an increased overall rate compared with those with other neuromuscular conditions. These included deep wound infection and hepatotoxicity. Hepatotoxicity was unique to DMD patients, and we recommend peri-operative vigilance after correction of a scoliosis in this group.

Cite this article: Bone Joint J 2014; 96-B:943–9.

Objectives

In order to ensure safety of the cell-based therapy for bone regeneration, we examined in vivo biodistribution of locally or systemically transplanted osteoblast-like cells generated from bone marrow (BM) derived mononuclear cells.

Objective

To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro.

We studied 51 patients with osteo-articular tuberculosis who were divided into two groups. Group I comprised 31 newly-diagnosed patients who were given first-line antituberculous treatment consisting of isoniazid, rifampicin, ethambutol and pyrazinamide. Group II (non-responders) consisted of 20 patients with a history of clinical non-responsiveness to supervised uninterrupted antituberculous treatment for a minimum of three months or a recurrence of a previous lesion which on clinical observation had healed. No patient in either group was HIV-positive. Group II were treated with an immunomodulation regime of intradermal BCG, oral levamisole and intramuscular diphtheria and tetanus vaccines as an adjunct for eight weeks in addition to antituberculous treatment. We gave antituberculous treatment for a total of 12 to 18 months in both groups and they were followed up for a mean of 30.2 months (24 to 49). A series of 20 healthy blood donors served as a control group.

Twenty-nine (93.6%) of the 31 patients in group I and 14 of the 20 (70%) in group II had a clinicoradiological healing response to treatment by five months.

The CD4 cell count in both groups was depressed at the time of enrolment, with a greater degree of depression in the group-II patients (686 cells/mm³ (sd 261) and 545 cells/mm³ (sd 137), respectively; p < 0.05). After treatment for three months both groups showed significant elevation of the CD4 cell count, reaching a level comparable with the control group. However, the mean CD4 cell count of group II (945 cells/mm³ (sd 343)) still remained lower than that of group I (1071 cells/mm³ (sd 290)), but the difference was not significant. Our study has shown encouraging results after immunomodulation and antituberculous treatment in non-responsive patients. The pattern of change in the CD4 cell count in response to treatment may be a reliable clinical indicator.

The outcome after total hip replacement has improved with the development of surgical techniques, better pain management and the introduction of enhanced recovery pathways. These pathways require a multidisciplinary team to manage pre-operative education, multimodal pain control and accelerated rehabilitation. The current economic climate and restricted budgets favour brief hospitalisation while minimising costs. This has put considerable pressure on hospitals to combine excellent results, early functional recovery and shorter admissions.

In this review we present an evidence-based summary of some common interventions and methods, including pre-operative patient education, pre-emptive analgesia, local infiltration analgesia, pre-operative nutrition, the use of pulsed electromagnetic fields, peri-operative rehabilitation, wound dressings, different surgical techniques, minimally invasive surgery and fast-track joint replacement units.

Cite this article: Bone Joint J 2013;95-B:1587–94.

Most problems encountered in complex revision total knee arthroplasty can be managed with the wide range of implant systems currently available. Modular metaphyseal sleeves, metallic augments and cones provide stability even with significant bone loss. Hinged designs substitute for significant ligamentous deficiencies. Catastrophic failure that precludes successful reconstruction can be encountered. The alternatives to arthroplasty in such drastic situations include knee arthrodesis, resection arthroplasty and amputation. The relative indications for the selection of these alternatives are recurrent deep infection, immunocompromised host, and extensive non-reconstructible bone or soft-tissue defects.

Periprosthetic joint infection (PJI) is a devastating complication which can follow a total joint arthroplasty (TJA). Although rare, this ongoing threat undermines the success of TJA, a historically reputable procedure. It has haunted the orthopedic community for decades and several ongoing studies have provided insights and new approaches to effectively battle this multilayered problem.

This paper reviews the current literature concerning the main clinical factors which can impair the healing of fractures and makes recommendations on avoiding or minimising these in order to optimise the outcome for patients. The clinical implications are described.