Aims

Tobacco, in addition to being one of the greatest public health threats facing our world, is believed to have deleterious effects on bone metabolism and especially on bone healing. It has been described in the literature that patients who smoke are approximately twice as likely to develop a nonunion following a non-specific bone fracture. For clavicle fractures, this risk is unclear, as is the impact that such a complication might have on the initial management of these fractures.

Background. Wear particles are considered to be the major culprit for the aseptic loosening. Their characterization is thus crucial for the understanding of their bioreactivity and contribution to the development of aseptic loosening. Methods. Metal wear debris particles were analyzed directly in periprosthetic tissue resins by scanning electron microscopy (SEM) combined with back-scattered electron imaging (BSE) and energy dispersive X-ray spectroscopy (EDS). Four groups of tissue samples retrieved at revision operations of loosened hip implants with different bearing surfaces (metal-on-metal, ceramic-on-polyethylene and metal-on-polyethylene), and different material of the femoral stem (Ti alloy, CoCrMo and polymer combined with stainless steel) were investigated. Tissue samples were first analyzed histologicaly. Sections from the same paraffin blocks were then carbon coated and analyzed using SEM/BSE/EDS method. Results. Metal particles were detected in all samples. Their composition corresponded to the composition of the implant components. The gradation of metal particles ranged from +1 to +3. A considerable number of big metal particles were actually agglomerates of submicron particles visible only at higher magnification. The clustering of particles was observed primarily for CoCrMo and, to a lesser extent, for stainless steels particles. The median sizes of CoCrMo clusters in two groups of samples were 2.9 1.8 m (range, 0.5 to 7.6 m) and 3.2 1.0 m (range, 1.9 to 5.4 m). The effect of clustering was not observed for Ti particles. The median sizes of individual Ti particles determined in two groups of samples were 2.5 3.6 m (range, 0.4 to 17.3 m) and 4.3 2.8 m (range, 0.8 to 11.0 m). Conclusion. Scanning electron microscopy combined with back-scattered electron imaging is an appropriate and selective method to recognize metal particles in tissue sections, without being destructive to specimens. When the size of the particles is considered, however, it should be differed between the size of individual particles and size of clusters of particles. Besides its benefits, this study has some limitations: the detection of particles smaller than 0.4 m is difficult, and this method cannot be used to identify polyethylene particles

Introduction. The MITCH PCR is an anatomic, flexible, horse-shoe shaped acetabular component, with 2 polar fins. The rationale of the PCR cup design is to reproduce a near-physiological stress distribution in the bone adjacent to the prosthesis. The thin composite cup is designed to fuse and flex in harmony with the surrounding bony structure. Only the pathological acetabular cartilage and underlying subchondral bone of the horseshoe-shaped, load-bearing portion of the acetabular socket is replaced, thus preserving viable bone stock. The PCR is manufactured from injection moulded carbon fibre reinforced polyetheretherketone (PEEK), with a two layer outer surface comprising hydroxyapatite and plasma sprayed commercially pure titanium. It is implanted in conjunction with a large diameter low wear femoral head, producing a bearing that will generate minimal wear debris with relatively inert particles. Pre-clinical mechanical testing, finite element analysis and biocompatibility studies have been undertaken. FEA evaluation predicts preservation of host bone density in the load bearing segments. A pilot clinical study was completed on a proto-type version of the PCR cup (the “Cambridge” cup), achieving excellent 5 and 10 year results. Subjects and Methods. We report the three-year results from a two-centre, prospective clinical evaluation study of the MITCH PCR cup. Patient outcome has been assessed using standardised clinical and radiological examinations and validated questionnaires. The change in physical level of activity and quality of life has been assessed using the Oxford Hip Score, Harris Hip score and the EuroQol-5D score, at scheduled time-points. Serial radiographs have been analysed to monitor the fixation and stability of the components. Results and Conclusions. In total 25 PCR cups were implanted by 3 surgeons. There were 12 men and 13 women. The mean patient age at time of surgery was 67 years (range 57–74). An Accolade TMZF stem was used as the femoral component in 19 patients and an Exeter stem in 6. The mean Oxford Hip score improved from 19.8 pre-operatively to 45 at the latest follow-up. The mean Euroqol-5D score improved from 62.6 to 83.6 and the Harris Hip score improved from 49.9 to 90.6. Three adverse events were noted in 2 patients (2 chest infections and 1 deep vein thrombosis). One revision of the acetabular component was performed at 21 months for squeaking. This has been investigated and modification of the articular geometry has resolved the problem on in-vitro testing

Purpose. To analyse the early results of unconstrained pyrocarbon joint replacements in patients with osteo-arthritis of the metacarpo-phalangeal joints. Background. Silicone arthroplasty, as introduced by Swanson in 1962 has remained the most popular procedure to treat arthritis of the metacarpo-phalangeal (MCP) joints. However, despite providing good pain relief, they have shown to demonstrate breakage rates up to 82% at 5 years. This is of great concern in the osteoarthritis (OA) patient group, who tend to be younger and have higher functional demands compared to their rheumatoid counterparts. The newer unconstrained pyrolytic carbon MCP joint prostheses may therefore be more suitable in OA patients whose soft tissue constraints are intact and whose hand function is strong. This study is the first to analyse the results of this implant in a cohort of OA patients only, with prospective data. Methods. 19 primary pyrocarbon metacarpo-phalangeal joint replacements, in 11 patients (5 men and 6 women) were reviewed, with prospective data collection. The diagnosis was primary osteoarthritis in all patients. The mean age at operation was 66.4 years (range 55–82 years). 2 patients underwent concomitant trapiezectomy and one underwent DIPJ fusion. All patients were right hand dominant −75% underwent surgery in their dominant hand. Eleven of the nineteen joints were performed in the index finger, with the remainder in the middle finger. Mean follow up is 22.1 months (range 11–37). Results. At the 3 month post-operative hand therapy assessment, the arc of motion had improved from a mean of 32 degrees to 45 degrees and flexion had improved from a mean of 51 degrees to 66 degrees. Grip strength improved from a mean 20 to 27Kg. DASH scores significantly improved from a mean of 40 to 10 (p=0.01). All patients were satisfied with their outcomes and would have the surgery again. Pre-operative radiographs demonstrated joint narrowing in all patients but no evidence of heterotopic ossification, cystic change or erosions. Post-operatively, there has been no radiographic evidence of joint dislocation, resorption stress-shielding, loosening, migration or heterotopic ossification. There were three intra-operative complications of phalangeal fractures that were immediately treated with a cerclage wire. In one patient there has been a fracture of the proximal phalangeal implant at 14 months which was asymptomatic. One patient has required revision for mal-rotation of the implant leading to loss of index finger supination. Conclusion. Our results demonstrate excellent early results of pyrocarbon MCP joint arthroplasty in OA patients

Introduction. Primary malign tumors and solitary metastatic lesions of the thoracic and thoracolumbar spine are indications for radical en bloc resections. Extracompartimental tumor infiltration makes the achievement of adequate oncological resection more difficult and requires an extension of the resection margins. We present a retrospective clinical study of patients that underwent chest wall resection in combination with vertebrectomy due to sarcomas and solitary metastases for assessing the clinical outcome especially focusing on onco-surgical results. Method. From 01/2002 to 01/2009 20 patients (female/male: 8/12; mean age: 52 (range of age: 27–76yrs)) underwent a combined en bloc resection of chest wall and vertebrectomy for solitary primary spinal sarcoma and metastatic lesions. The median follow-up was 20,5 (3–80) months. Histological analysis revealed 17 primary tumors and 3 solitary metastatic lesions. In the group of primary tumors 10 sarcomas, 1 giant cell tumor, 2 PNET, 1 histiocytoma, 1 aggressiv fibrous dysplasia, 1 pancoast tumor and 1 plasmocytoma were histologically documented. We included 1 rectal carcinoma, 1 breast cancer metastases and 1 renal cell carcinoma. All patients underwent a chestwall resection en bloc with multilevel (1/2/3/4 segments: n=4/6/6/4) hemi (n=7) or total vertebrectomy (n=13) with subsequent defect reconstruction. Reconstruction of the spinal defect following total resections was accomplished by combined dorsal stabilization and carbon cage interposition. The chest wall defects were closed with a goretex ® -patch. One patient also received a musculocutaneus latissimus dorsi flap. Results. The surgical margins were R0 in 19 (wide in 14, marginal in 5) and one R1 resection. Marginal/R1 resections were due to extracompartimental sarcoma invasion (spinal canal) and dural involvement. In these patients postoperative radiotherapy was performed. Surgical complications requiring revision occurred in 1 patient due to injury of the ductus thoracicus and persisting chylothorax. Temporary subileus or mild pneumonia appeared in 3 patients. No superficial/deep infection or neurological deficits (except those related to oncologically required dissection of thoracic nerve roots) were observed. At follow up 2 patients died due to the disease after 7,5 months. Local recurrences were seen in 3 patients at median 24 months (13–43). Pulmonary metastases necessitating polychemotherapy were seen in 7 patients after median 17 months (7–44). Conclusion. Despite the only midterm follow up, the combined en bloc resection of chest wall and multilevel en bloc spondylectomy/hemivertebrectomy is a challenging but safe and effective technique in order to achieve adequate margins and local control in selected with spinal sarcomas extending to the dorsolateral chest wall

Introduction. Patients suffering from finger joint pain or dysfunction due to arthritis and traumatic injury may require arthroplasty and joint replacement. Single-part silicone-based implants remain the material of choice and most widely used option, although reports on their long-term clinical performance are variable. For trauma indications, patients have a high expectation of functionality necessitating the use of materials with high wear resistance and mechanical performance. A new proximal inter phalangeal (PIP) joint designed by Zrinski AG (Wurmlingen, Germany), comprising a self-mating carbon fibre reinforced polyetheretherketone (CFR-PEEK) coupling, may provide a suitable alternative. Here we describe the wear performance of the CFR-PEEK components in a PIP joint wear simulator and subsequent characterisation of the wear particles. Methods. Four proximal and distal PIP components were milled (Zrinski AG) from CFR-PEEK (Invibio Ltd, UK) and subjected to wear testing (Endo Lab ® GmbH, Germany). The test was conducted at 37°C over 5 million cycles in 25% bovine serum (refreshed every 0.5 million cycles). The load was a static force of 63N applied at a frequency of 1Hz with a flexion/extension angle of ±40°. Wear rate was determined by mass loss from each component. Pooled serum samples from the wear simulator were subjected to protein digest and the remaining particulate debris isolated by serial filtration through 10μm, 1μm and 0.1μm filters. Particle size and morphology was subsequently determined by scanning electron microscopy (SEM) (Continuum Blue, UK). Results. Both components exhibited high resistance to wear, with the proximal component resulting in a wear rate of 0.09mg/million cycles, whilst that of the distal component was 0.07mg/million cycles. Particle analysis revealed that the majority of debris generated during the wearing in phase (0.5 million cycles) was <0.5μm in diameter. During the steady state phase (0.5–3 million cycles) a large peak in particle size was observed in the 2μm diameter range, whilst in the latter stage (3–5 million cycles) peaks in particle size were seen at 0.4μm and 2μm. During each stage, both the particle count and aspect ratio remained relatively unchanged. Conclusion. Under these test conditions the CFR-PEEK coupling demonstrated a linear and consistently low wear rate over the 5 million cycle test period, with the majority of particles generated being <2μm in diameter. The low wear rate and biocompatibility demonstrated by CFR-PEEK suggests it is a suitable alternative to silicone in PIP joint prostheses. Acknowledgements. The authors would like to thank Zrinski AG, Christian Kaddick at EndoLab GmbH for the wear simulator work and Mark Yeoman at Continuum Blue Ltd. for particle analysis

Objectives

External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF).

Objectives

Bisphosphonates are widely used as first-line treatment for primary and secondary prevention of fragility fractures. Whilst they have proved effective in this role, there is growing concern over their long-term use, with much evidence linking bisphosphonate-related suppression of bone remodelling to an increased risk of atypical subtrochanteric fractures of the femur (AFFs). The objective of this article is to review this evidence, while presenting the current available strategies for the management of AFFs.

Between 2000 and 2006 we performed salvage tibiotalar arthrodesis in 17 diabetic patients (17 ankles) with grossly unstable ankles caused by bimalleolar fractures complicated by Charcot neuro-arthropathy. There were ten women and seven men with a mean age of 61.6 years (57 to 69). A crossed-screw technique was used. Two screws were used in eight patients and three screws in nine. Additional graft from the malleoli was used in all patients. The mean follow-up was 26 months (12 to 48) and the mean time to union was 5.8 months (4 to 8). A stable ankle was achieved in 14 patients (82.4%), nine of whom had bony fusion and five had a stiff fibrous union. The results were significantly better in underweight patients, in those in whom surgery had been performed three to six months after the onset of acute Charcot arthropathy, in those who had received anti-resorptive medication during the acute stage, in those without extensive peripheral neuropathy, and in those with adequate peripheral oxygen saturation (> 95%). The arthrodesis failed because of avascular necrosis of the talus in only three patients (17.6%), who developed grossly unstable, ulcerated hindfeet, and required below-knee amputation.